JP2016130521A - Internal combustion engine control device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To suppress a fluctuation of an acceleration profile after acceleration is started if a rotating state of a turbine at a time of starting the acceleration fluctuates due to various factors.SOLUTION: A control device of an internal combustion engine provided with a wastegate valve which is configured to be able to control a power received by a turbine from exhaust gas by detouring part of the exhaust gas from an upstream section of the turbine to a downstream section thereof, comprises: an opening-degree control unit that controls an opening degree of the wastegate valve in response to a demanded torque in a supercharged area of the internal combustion engine; and an opening-degree correction unit that corrects the opening degree of the wastegate valve controlled by the opening-degree control unit so that the opening degree becomes higher if a rotating speed of the turbine is on the decrease at a time of starting acceleration when the internal combustion engine is accelerated.SELECTED DRAWING: Figure 7

Description

  The present invention relates to a control device for an internal combustion engine.

  2. Description of the Related Art Conventionally, there is known a control technology for an internal combustion engine with a supercharger that is operated by appropriately switching between a waste gate valve opening control mode for uniformly opening a waste gate valve and a normal supercharging pressure control mode ( For example, Patent Document 1).

JP 2003-343273 A

  However, when the rotational state of the turbine at the start of acceleration varies due to various factors, there is a problem that the acceleration profile after the acceleration starts varies significantly.

The control apparatus for an internal combustion engine according to claim 1 includes a wastegate valve configured to control a work rate that the turbine receives from the exhaust gas by diverting a part of the exhaust gas from the upstream portion to the downstream portion of the turbine. A control device for an internal combustion engine, wherein an opening degree control unit that controls an opening degree of a waste gate valve according to a required torque in a supercharging region of the internal combustion engine, and rotation of a turbine at the start of acceleration when the internal combustion engine is accelerated When the speed is in a decreasing state, an opening correction unit that corrects the opening of the waste gate valve controlled by the opening control unit to the open side is provided.
The control apparatus for an internal combustion engine according to claim 7 includes a waste gate valve configured to control a work rate that the turbine receives from the exhaust gas by diverting a part of the exhaust gas from the upstream portion to the downstream portion of the turbine. A control device for an internal combustion engine, wherein when the acceleration by the same accelerator operation amount from the same rotational speed and the same load of the internal combustion engine is accelerated, the larger the opening of the waste gate valve at the start of acceleration, the more the waste gate valve during the acceleration period An opening degree control unit that controls the opening degree closer to the closing side is provided.

  According to the present invention, when the rotational speed of the turbine at the start of acceleration is in a reduced state during acceleration of the internal combustion engine, the opening degree of the waste gate valve is corrected to the open side. A uniform acceleration profile can be realized under the same acceleration pedal depression conditions.

1 is a schematic configuration diagram of an entire system of an engine control apparatus according to an embodiment of the present invention. The figure explaining the influence on the fully open acceleration behavior of the internal combustion engine when the state of the waste gate valve at the start of acceleration differs The block diagram explaining the function of ECU by 1st Embodiment The figure which shows an example of a target throttle valve opening degree map and a target wastegate valve opening degree map The figure which shows the relationship between the time variation | change_quantity of the turbine rotational speed at the time of an acceleration start, and the corrected amount of the opening degree of the waste gate valve during an acceleration period Timing chart explaining acceleration control according to the present embodiment Timing chart showing acceleration control when the vehicle is accelerated by the driver during deceleration according to the first and second embodiments Timing chart showing acceleration control when the vehicle is further accelerated by the driver during acceleration according to the first and second embodiments Flowchart for explaining the operation according to the first and second embodiments Timing chart explaining acceleration control according to comparative example The block diagram explaining the function of ECU by 2nd Embodiment The figure which shows the relationship between the difference of the turbine rotational speed at the time of an acceleration start, and a reference turbine rotational speed, and the correction amount of the opening degree of the waste gate valve during an acceleration period The figure explaining switching control of the operation mode of an internal-combustion engine by cooperative control of a throttle valve and a wastegate valve in a 3rd embodiment. The block diagram explaining the function of ECU by 3rd Embodiment Timing chart showing acceleration control in the third embodiment Flowchart for explaining the operation according to the third embodiment The figure which shows an example of the two-dimensional map of the rotational speed and charging efficiency of an internal combustion engine provided with the Cooled-EGR system in 4th Embodiment. Diagram showing the relationship between the waste gate valve opening, the throttle valve downstream pressure, and the turbine rotation speed, and the charging efficiency by introducing the Cooled-EGR system The block diagram explaining the function of ECU by 4th Embodiment Timing chart showing acceleration control in the fourth embodiment Flowchart for explaining the operation according to the fourth embodiment

-First embodiment-
An internal combustion engine control apparatus according to a first embodiment of the present invention will be described with reference to the drawings.
FIG. 1 is a schematic configuration diagram of the entire system of the engine control apparatus 100. The engine control device 100 includes an internal combustion engine 1, an intake air temperature sensor 2, a turbocharger 3, an air bypass valve 4, an intercooler 5, a supercharging temperature sensor 6, a throttle valve 7, an intake manifold 8, a supercharging pressure sensor 9, Flow enhancement valve 10, intake valve 11, exhaust valve 13, fuel injection valve 15, spark plug 16, knock sensor 17, crank angle sensor 18, waste gate valve 19, air-fuel ratio sensor 20, exhaust purification catalyst 21, EGR (Exhausted Gas) Recirculation) tube 22, EGR cooler 23, EGR valve 24, temperature sensor 25, differential pressure sensor 26 and ECU (Electronic Con
trol unit) 27.

  The internal combustion engine 1 communicates with an intake passage and an exhaust passage. An air flow sensor and an intake air temperature sensor 2 built in the air flow sensor are assembled in the intake passage. The turbocharger 3 includes a compressor 3a and a turbine 3b. The compressor 3a is connected to the intake passage, and the turbine 3b is connected to the exhaust passage. The turbine 3b of the turbocharger 3 converts the energy of the exhaust gas from the internal combustion engine 1 into the rotational energy of the turbine blades. The compressor 3a of the turbocharger 3 compresses the intake air flowing in from the intake passage by the rotation of the compressor blade connected to the turbine blade.

  The intercooler 5 is provided downstream of the compressor 3a of the turbocharger 3, and cools the intake air temperature of the intake air that has been adiabatically compressed by the compressor 3a and has risen. The supercharging temperature sensor 6 is assembled downstream of the intercooler 5 and measures the temperature of the intake air (supercharging temperature) cooled by the intercooler 5. The throttle valve 7 is provided downstream of the supercharging temperature sensor 6, restricts the intake flow path, and controls the amount of intake air flowing into the cylinder of the internal combustion engine 1. The throttle valve 7 is constituted by an electronically controlled butterfly valve capable of controlling the valve opening independently of the amount of accelerator pedal depression by the driver. Downstream of the throttle valve 7, an intake manifold 8 with a supercharging pressure sensor 9 is communicated.

  The intake manifold 8 provided downstream of the throttle valve 7 and the intercooler 5 may be integrated. In this case, since the volume from the downstream of the compressor 3a to the cylinder can be reduced, the acceleration / deceleration response can be improved.

  The flow enhancement valve 10 is arranged downstream of the intake manifold 8 and enhances the turbulence in the flow of the cylinder by causing a drift in the intake air. The internal combustion engine 1 includes an intake valve 11 and an exhaust valve 13. The intake valve 11 and the exhaust valve 13 each have a variable valve mechanism for making the valve opening / closing phase continuously variable. Sensors 12 and 14 for detecting the opening / closing phase of the valves are respectively assembled to the variable valve mechanisms of the intake valve 11 and the exhaust valve 13. The cylinder liner portion of the internal combustion engine 1 is provided with a direct fuel injection valve 15 that directly injects fuel into the cylinder. The fuel injection valve 15 may be a port injection system that injects fuel into the intake port.

  An ignition plug 16 is attached to the cylinder head portion of the internal combustion engine 1 to expose an electrode portion in the cylinder and ignite a combustible air-fuel mixture by spark. The knock sensor 17 is provided in the cylinder block and detects the presence or absence of knock occurring in the combustion chamber. The crank angle sensor 18 is assembled to the crankshaft and outputs a signal corresponding to the rotation angle of the crankshaft to the ECU 27 described later as a signal indicating the rotation speed of the crankshaft for each combustion cycle.

  The air-fuel ratio sensor 20 is provided downstream of the turbine 3 b of the turbocharger 3 and outputs a signal indicating the detected oxygen concentration, that is, the air-fuel ratio, to the ECU 27. The exhaust purification catalyst 21 is provided downstream of the air-fuel ratio sensor 20, and purifies harmful exhaust gas components such as carbon monoxide, nitrogen compounds and unburned hydrocarbons in the exhaust gas by catalytic reaction.

  The turbocharger 3 is provided with an air bypass valve 4 and a waste gate valve 19. The air bypass valve 4 is disposed on a bypass flow path connecting the upstream and downstream of the compressor 3a in order to prevent the pressure from the downstream of the compressor 3a to the upstream of the throttle valve 7 from rising excessively. When the throttle valve 7 is suddenly closed in a supercharged state, the air bypass valve 4 is opened according to the control of the ECU 27, so that the compressed intake air downstream of the compressor 3a passes through the bypass flow path to the compressor. It flows back to the upstream part of 3a. As a result, the supercharging pressure can be reduced.

  The waste gate valve 19 is disposed on a bypass flow path that connects the upstream side and the downstream side of the turbine 3b. The waste gate valve 19 is an electric valve whose valve opening can be freely controlled with respect to the boost pressure under the control of the ECU 27. When the opening degree of the waste gate valve 19 is adjusted by the ECU 27 based on the supercharging pressure detected by the supercharging pressure sensor 9, a part of the exhaust gas passes through the bypass flow path, so that the exhaust gas is given to the turbine 3b. You can reduce your work. As a result, the supercharging pressure can be maintained at the target pressure. The details of the opening control of the waste gate valve 19 will be described later.

  The EGR pipe 22 communicates the exhaust flow path downstream of the exhaust purification catalyst 21 and the intake flow path upstream of the compressor 3a, and diverts the exhaust gas from the downstream of the exhaust purification catalyst 21, so that the upstream part of the compressor 3a. To reflux. The EGR cooler 23 provided in the EGR pipe 22 cools the exhaust gas. The EGR valve 24 is provided downstream of the EGR cooler 23 and controls the flow rate of the exhaust gas. The EGR pipe 22 is provided with a temperature sensor 25 that detects the temperature of the exhaust gas upstream of the EGR valve 24 and a differential pressure sensor 26 that detects the differential pressure between the upstream and downstream of the EGR valve 24.

  The ECU 27 includes a CPU, a ROM, a RAM, and the like, and is an arithmetic circuit that controls each component of the engine control device 100 and executes various data processes. The ECU 27 is connected to the above-described various sensors and various actuators. The ECU 27 controls the operation of actuators such as the throttle valve 7, the fuel injection valve 11, the intake / exhaust valves 12 and 14 with a variable valve mechanism, and the EGR valve 24. Further, the ECU 27 detects the operating state of the internal combustion engine 1 based on signals input from various sensors, and ignites the spark plug 16 at a timing determined according to the operating state.

Hereinafter, the influence of the opening degree of the waste gate valve 19 provided in the turbocharger 3 on the acceleration behavior of the internal combustion engine 1 will be described.
FIG. 2 explains the influence on the acceleration behavior of the internal combustion engine 1 when the wastegate valve 19 is provided in the turbocharger 3 and the state of the wastegate valve 19 at the start of acceleration, that is, when the opening degree is different. It is a figure to do. 2A shows the relationship between the accelerator pedal depression amount and time, and FIG. 2B shows the relationship between the opening degree of the throttle valve 7 and time. FIG. 2 (c) shows the relationship between the waste gate valve 19 and time, and FIG. 2 (d) shows the relationship between the target charging efficiency and time. FIG. 2E shows the relationship between the turbine rotational speed and time, and FIG. 2F shows the relationship between the differential pressure across the throttle valve 7 and time. 2 (b) to 2 (f), the case where the waste gate valve 19 is closed before the start of acceleration is indicated by a solid line as Condition 1, and the case where the waste gate valve 19 is opened before the start of acceleration is shown as Condition 2. As shown by a broken line.

  FIG. 2A shows a case where the accelerator pedal depression amount is increased step-up by the driver between time t1 and time t2. As shown in FIG. 2B, before the acceleration is started at time t1, the throttle valve 7 in the condition 1 is set to the closed side as compared with the condition 2. Then, after the acceleration is started at time t1, when it is determined that the required torque is in the supercharging region, the throttle valve 7 is set to be fully opened.

  As shown in FIG. 2 (c), when acceleration is started at time t1, the waste gate valve 19 is set to be fully closed regardless of the condition 1 or the condition 2. Is done. By setting the waste gate valve 19 to be fully closed after the start of acceleration, as shown in FIG. 2D, the charging efficiency increases after the vehicle is in an accelerated state. In this case, as shown in FIG. 2E, the rotational speed of the turbine 3b is higher in the condition 1 than in the condition 2. This is because the difference in rotational speed of the turbine 3b before the time t1 does not immediately decrease even when the vehicle is accelerated after the time t1, so that the waste gate valve 19 is fully opened before the time t1 as in condition 2. If so, the increase in supercharged work is delayed. Since the difference in the rotational speed of the turbine 3b does not decrease, as shown in FIG. 2D, the target charging efficiency is reached at time t3 in the case of condition 1, but at time t4 that is later than time t3 in the case of condition 2. To reach the target filling efficiency. Therefore, in the case of the condition 2, since the increase in the charging efficiency is delayed as compared with the case of the condition 1, it takes time to reach the target charging efficiency, that is, the target required torque. In other words, in the case of condition 2, the acceleration performance is deteriorated.

  As shown in FIG. 2 (f), in the case of condition 1, the differential pressure across the throttle valve 7 before acceleration is started at time t1 is larger than in the case of condition 2. Such a differential pressure across the throttle valve 7 causes energy loss during intake / exhaust to the internal combustion engine 1, that is, pump loss, and also affects an increase in the rotational speed of the turbine 3b.

  The engine control apparatus 100 according to the present embodiment controls the opening degree of the waste gate valve 19 during acceleration in order to prevent the above-described deterioration in acceleration performance, pump loss, and the like. In this case, the engine control device 100 is accelerated by the same accelerator pedal depression amount from the same rotational speed and load condition of the internal combustion engine 1 with respect to the internal combustion engine 1 that performs torque control in the supercharging region by the wastegate valve 19. Even if it is, it will achieve a uniform acceleration profile. That is, the ECU 27 of the engine control device 100 takes into account the amount of change in the state of the turbocharger 3 caused by the transient of the internal combustion engine 1 based on the amount of change in the rotational speed of the turbine 3b over time, and the throttle valve 7 and waste gate valve 19 are controlled. Hereinafter, processing by the ECU 27 will be described in detail.

  FIG. 3 is a functional block diagram schematically illustrating functions of the ECU 27. As shown in FIG. 3, the ECU 27 includes a required torque calculation unit 701, a target charging efficiency calculation unit 702, a target throttle valve opening calculation unit 703, an exhaust gas total energy calculation unit 704, a target W / G ratio calculation unit 705, a target turbine. The work calculation unit 706, the target compressor work calculation unit 707, the turbine rotational speed transient behavior calculation unit 708, the target W / G opening calculation unit 709, the target steady supercharging pressure calculation unit 710, and the PID steady correction amount calculation unit 711 are functional. Prepare for.

  Based on the rotational speed of the internal combustion engine 1 and the accelerator pedal depression amount by the driver, the required torque calculation unit 701 calculates torque required for the internal combustion engine 1 (hereinafter referred to as required torque) by map search and interpolation. . The required torque of the internal combustion engine 1 obtained in advance by adaptation is represented on a two-dimensional map with the rotation speed of the internal combustion engine 1 and the accelerator pedal depression amount as axes, and this map is recorded in a predetermined recording area in advance. Has been.

  The target charging efficiency calculation unit 702 calculates the target charging efficiency of the internal combustion engine 1 by map search and interpolation interpolation based on the rotation speed of the internal combustion engine 1 and the required torque calculated by the required torque calculation unit 701. Note that the target charging efficiency of the internal combustion engine 1 obtained by adaptation in advance is represented on a two-dimensional map with the rotational speed of the internal combustion engine 1 and the required torque as axes, and this map is recorded in a predetermined recording area in advance. ing.

  A target throttle valve opening calculation unit 703 opens a target throttle valve 7 by map search and interpolation interpolation based on the rotational speed of the internal combustion engine 1 and the target charging efficiency calculated by the target charging efficiency calculation unit 702. Degree (hereinafter referred to as a target throttle valve opening). The target throttle valve opening calculator 703 outputs an instruction signal (throttle valve opening command value) so that the opening of the throttle valve 7 becomes the calculated target throttle valve opening. Note that the target throttle valve opening obtained by adaptation in advance is represented on a two-dimensional map with the rotational speed of the internal combustion engine 1 and the target charging efficiency as axes, and this map is recorded in a predetermined recording area in advance. Yes.

  FIG. 4 (a) schematically shows a map for setting the target throttle valve opening. On the throttle valve target opening contour shown by the broken line in FIG. 4A, the opening of the throttle valve 7 determined by the rotational speed of the internal combustion engine 1 and the charging efficiency is equal. In the non-supercharging range, that is, when the internal combustion engine 1 is at atmospheric pressure or lower, the opening of the throttle valve 7 increases as the rotational speed of the internal combustion engine 1 increases and the charging efficiency increases. Set to In the supercharging region, that is, when the internal combustion engine 1 exceeds atmospheric pressure, the throttle valve 7 is set to be fully open.

The exhaust gas total energy calculation unit 704 shown in FIG. 3 calculates the total energy of the exhaust gas discharged from the cylinder based on the rotation speed of the internal combustion engine 1 and the target charging efficiency calculated by the target charging efficiency calculation unit 702. . In this case, first, the exhaust gas total energy calculation unit 704 calculates the mass flow rate of the exhaust gas discharged from the cylinder using the rotation speed of the internal combustion engine 1, the calculated target charging efficiency, and the target air-fuel ratio. Next, the exhaust gas total energy calculation unit 704 calculates the exhaust gas temperature by map search and interpolation interpolation based on the rotation speed of the internal combustion engine 1 and the calculated target charging efficiency. Then, the exhaust gas total energy calculation unit 704 calculates the total energy of the exhaust gas using the following equation (1), using the calculated mass flow rate of the exhaust gas, the exhaust gas temperature, and the specific heat of the exhaust gas as parameters. The temperature of the exhaust gas discharged from the cylinder determined in advance is represented on a two-dimensional map with the rotational speed of the internal combustion engine 1 and the target charging efficiency as axes, and this map is recorded in a predetermined recording area in advance. Has been.
Exhaust gas total energy = specific heat x exhaust gas temperature x exhaust gas mass flow rate (1)

  A target W / G ratio calculation unit 705 is based on the rotation speed of the internal combustion engine 1 and the target charging efficiency calculated by the target charging efficiency calculation unit 702, and a target waste gate ratio (target target) by map search and interpolation. Wastegate ratio) is calculated. The waste gate ratio is a mass ratio of gas that bypasses the bypass passage provided with the waste gate valve 19 without passing through the turbine 3b in the exhaust gas discharged from the cylinder, and is represented by a value of 0 to 1. The When the internal combustion engine 1 is at the same rotational speed in the supercharging region, the target W / G ratio calculation unit 705 sets a value so that the waste gate ratio decreases as the target charging efficiency increases. On the other hand, the target W / G ratio calculation unit 705 sets the waste gate ratio to 1 which is the maximum value regardless of the target charging efficiency in the non-supercharging region, and causes the waste gate valve 19 to be fully opened. Note that the target wastegate ratio obtained by adaptation in advance is represented on a two-dimensional map with the rotational speed of the internal combustion engine 1 and the target charging efficiency as axes, and this map is recorded in a predetermined recording area in advance.

The target turbine work calculation unit 706 is based on the exhaust gas total energy calculated by the exhaust gas total energy calculation unit 704 and the target wastegate ratio calculated by the target W / G ratio calculation unit 705, using the following equation (2). Is used to calculate the target turbine work.
Target turbine work = target wastegate ratio x total exhaust gas energy (2)

  Based on the target turbine work calculated by the target turbine work calculation unit 706, the target compressor work calculation unit 707 calculates the target compressor work by map search and interpolation. It should be noted that the target compressor work obtained by adaptation in advance is represented by a table with the target turbine work as an axis, and this map is recorded in a predetermined recording area in advance.

The turbine rotational speed transient behavior calculation unit 708 uses the following formula (3) based on the inertia moment of the turbine blade, the turbine rotational friction work, the calculated target turbine work, and the calculated target compressor work. Then, the time change rate of the rotational speed of the turbine 3b is calculated. Then, the turbine rotational speed transient behavior calculation unit 708 calculates the transient behavior of the rotational speed of the turbine 3b by time-integrating the calculated temporal change rate of the rotational speed of the turbine 3b.
Time change rate of turbine rotation speed = (target turbine work−target compressor work−turbine rotation friction work) / moment of inertia (3)

  The target W / G opening degree calculation unit 709 is based on the rotation speed of the internal combustion engine 1 and the target turbine work calculated by the target turbine work calculation unit 706 and performs a map search and interpolation target interpolation for the waste gate valve 19 target reference. An opening (hereinafter referred to as a target wastegate valve reference opening) is calculated. The target wastegate valve reference opening determined in advance by adaptation is represented by a table with the rotational speed of the internal combustion engine 1 and the target turbine work as axes, and this map is recorded in a predetermined recording area in advance. .

  FIG. 4B schematically shows a map for setting the target wastegate valve reference opening. On the waste gate valve target opening contour indicated by a broken line in FIG. 4B, the opening of the waste gate valve 19 determined by the rotation speed of the internal combustion engine 1 and the charging efficiency is equal. When the exhaust flow rate is equal to or lower than the flow rate indicated by the equal flow line, the waste gate valve 19 is set to be fully opened. When the exhaust flow rate exceeds the flow rate indicated by the equal flow line, the waste gate valve 19 is set to the closed side as the rotational speed of the internal combustion engine 1 decreases and the charging efficiency increases.

  Further, the target W / G opening degree calculation unit 709 in FIG. 3 opens the target waste gate valve based on the temporal change rate of the rotation speed of the turbine 3b during the transient behavior calculated by the turbine rotation speed transient behavior calculation unit 708. Calculate the measure. In this case, the target W / G opening degree calculation unit 709 sets the target wastegate valve reference opening degree to the closed side when the time change rate of the rotational speed of the turbine 3b in the transient behavior at the start of acceleration is a positive value. It correct | amends and calculates a target wastegate valve-opening amount. On the other hand, the target W / G opening calculation unit 709 corrects the target wastegate valve reference opening to the open side when the time change rate of the rotational speed of the turbine 3b in the transient behavior at the start of acceleration is a negative value. Then, the target wastegate valve opening amount is calculated.

  FIG. 5 is a diagram showing the relationship between the time change rate of the rotational speed of the turbine 3b at the start of acceleration and the correction amount of the opening degree of the waste gate valve 19 during the acceleration period. When the time change rate of the turbine rotation speed at the start of acceleration is a positive value, it indicates that the rotation of the turbine 3b is in a state of insufficient rotation. Therefore, the waste gate valve 19 is corrected to the closed side in order to increase the rotational speed of the turbine 3b. On the other hand, when the time change rate of the rotational speed of the turbine 3b at the start of acceleration is a negative value, it indicates that the turbine 3b is rotating excessively. Accordingly, the waste gate valve 19 is corrected to the open side in order to reduce the rotational speed of the turbine 3b.

  The target steady supercharging pressure calculation unit 710 in FIG. 3 is based on the rotation speed of the internal combustion engine 1 and the target charging efficiency calculated by the target charging efficiency calculation unit 702, and performs a map search and interpolation interpolation to obtain the target steady supercharging pressure. Is calculated. Note that the target steady supercharging pressure obtained by adaptation in advance is represented by a table with the rotational speed of the internal combustion engine 1 and the target charging efficiency as axes, and this map is recorded in a predetermined recording area in advance.

  The PID steady correction amount calculation unit 711 calculates the feedback control amount based on the PID control based on the difference between the current supercharging pressure and the target steady supercharging pressure, thereby calculating the target W / G opening calculation unit 709. The target wastegate valve opening amount is steadily corrected. Then, the PID steady correction amount calculation unit 711 outputs the steady corrected target waste gate valve opening amount as a W / G valve opening command value to the waste gate valve 19 to control the opening of the waste gate valve 19. As a result, the torque profile corresponding to the acceleration request by the driver is realized by controlling the opening degree of the waste gate valve 19 by suppressing the fluctuation of the acceleration profile due to insufficient rotation or excessive rotation of the turbine rotation speed at the start of acceleration. The

  The exhaust gas total energy calculation unit 704, the target W / G ratio calculation unit 705, the target turbine work calculation unit 706, the target compressor work calculation unit 707, and the turbine rotation speed transient behavior calculation unit 708 calculate the rotation speed of the turbine 3b. It is not limited to. That is, the same can be obtained by providing a turbine rotation speed sensor and directly detecting the rotation speed of the turbine 3b.

  FIG. 6 shows acceleration control executed by the ECU 27 performing the above-described processing. FIG. 6A shows the relationship between the accelerator pedal depression amount and time under three different conditions, and FIG. 6B shows the relationship between the opening degree of the throttle valve 7 and the time according to the accelerator pedal depression amount. FIG. 6C shows the relationship between the opening degree of the waste gate valve 19 according to the accelerator pedal depression amount and time, and FIG. 6D shows the opening of the throttle valve 7 and the waste gate valve 19 according to the accelerator pedal depression amount. The relationship between filling efficiency and time by controlling the degree is shown. In FIG. 6, the case where the accelerator pedal depression amount is the maximum among the three conditions is indicated by a solid line as Condition 1, the case where the accelerator pedal depression amount is intermediate is indicated by a broken line as Condition 2, and the case where the accelerator pedal depression amount is the minimum Condition 3 is indicated by a one-dot chain line.

  FIG. 6A shows that the accelerator pedal depression amount increased, that is, accelerated between times t1 and t2. As the accelerator pedal depression amount increases, the throttle valve 7 is fully opened as shown in FIG. 6 (b). On the other hand, as shown in FIG. 6C, when the accelerator pedal depression amount is in the maximum condition 1, the opening degree of the waste gate valve 19 is set to the most closed side among the three conditions. In the case of the condition 3 where the accelerator pedal depression amount is the minimum, the opening degree of the waste gate valve 19 is set to the most open side among the three conditions. When the accelerator pedal depression amount is an intermediate condition 2, the opening degree of the waste gate valve 19 is set to an intermediate opening degree among the three conditions. That is, as the accelerator pedal depression amount is larger, the opening degree of the waste gate valve 19 at the end of acceleration (time t2) is set to be closer.

  When the throttle valve 7 and the waste gate valve 19 are controlled as described above, the charging efficiency increases and reaches the target charging efficiency determined based on the accelerator pedal stroke. As shown in FIG. 6D, the target charging efficiency is reached at time t3 in condition 1, at time t4 in condition 2, and at time t5 in condition 3. That is, the longer the accelerator pedal depression amount, in other words, the shorter the opening degree of the waste gate valve 19 is set to the closed side, the shorter the time until the target charging efficiency is reached. When the target charging efficiency is reached, the opening degree of the waste gate valve 19 is controlled so that the charging efficiency is maintained in the target state. As shown in FIG. 6C, the opening degree of the waste gate valve 19 is set to the open side at time t3 in the case of condition 1, at time t4 in condition 2, and at time t5 in condition 3. As a result, in the steady state, unnecessary work of the turbocharger 3 is eliminated to reduce fuel consumption, and in the accelerated state, a torque profile according to the acceleration request from the driver is realized.

  FIG. 7 shows the throttle valve 7 and the waste gate valve in consideration of the increase fluctuation of the turbocharger 3 caused by the transition of the internal combustion engine 1, that is, the case where the vehicle is accelerated by the driver during deceleration. It is a timing chart which shows the acceleration control at the time of controlling the opening degree of 19. FIG. 7A shows the relationship between the accelerator pedal depression amount and time, and FIG. 7B shows the relationship between the opening degree of the throttle valve 7 and the time according to the accelerator pedal depression amount. FIG. 7C shows the relationship between the opening degree of the waste gate valve 19 corresponding to the accelerator pedal depression amount and time, and FIG. 7D shows the relationship between the turbine rotation speed and time. FIG. 7 (e) shows the relationship between the downstream pressure of the throttle valve 7 and time, and FIG. 7 (f) shows that the opening degree of the throttle valve 7 and the waste gate valve 19 is controlled in accordance with the accelerator pedal depression amount. The relationship between filling efficiency and time is shown. 7C to 7F, the reference acceleration condition among the three conditions is indicated by a solid line as condition 1, and the case where no transient correction is performed on the waste gate valve 19 is indicated by a broken line as condition 2, A case where transient correction is performed on the valve 19 is indicated by a one-dot chain line as Condition 3.

  FIG. 7A shows that the accelerator pedal depression amount is increased, that is, accelerated between times t1 and t2. If it is determined that the required torque is in the supercharging region, as shown in FIG. 7B, the throttle valve 7 is fully opened as the accelerator pedal depression amount increases. As shown in FIG. 7C, in the case of condition 1 and condition 2, the waste gate valve 19 at the end of acceleration (time t2) is closed so that the opening is substantially the same. Is set. On the other hand, in the case of condition 3, the opening degree of the waste gate valve 19 at time t2 is set to be more open than in the case of condition 1 and condition 2. For this reason, as shown in FIG. 7 (d), the increase profile of the turbine rotational speed in the condition 2 where the transient correction is not performed is the increase profile of the rotational speed of the turbine 3b in the condition 1 which is the reference acceleration condition. Compared to the previous year, it will increase significantly. Further, as shown in FIG. 7E, in the case of condition 2, the downstream pressure of the throttle valve 7 changes significantly on the increase side as compared with the increase profile of the downstream pressure of the throttle valve 7 in the case of condition 1. To do. As a result, as shown in FIG. 7 (f), the charging efficiency in the case of condition 2 changes on the increase side as compared with the increase profile of the charging efficiency in the case of condition 1, and becomes the target charging efficiency in condition 1. The target charging efficiency is reached at time t3 earlier than time t4.

  As shown in FIG. 7D, the rotational speed of the turbine 3b in the case of the condition 3 with the transient correction compared with the case without the transient correction as described above (condition 2) is as shown in FIG. It becomes a profile close to the increase profile of the rotational speed of the turbine 3b in the case of a certain condition 1. Further, as shown in FIG. 7E, in the case of condition 3, the downstream pressure of the throttle valve 7 substantially matches the increase profile of the downstream pressure of the throttle valve 7 in the case of condition 1. As a result, as shown in FIG. 7 (f), the filling efficiency in the case of the condition 3 substantially matches the increase profile of the filling efficiency in the case of the condition 1, and therefore the target filling at the time t4 in the conditions 1 and 3 Reach efficiency.

  FIG. 8 shows the throttle valve 7 and the waste gate in consideration of the reduction fluctuation of the turbocharger 3 caused by the transient of the internal combustion engine 1, that is, the case where the vehicle is further accelerated by the driver during acceleration. It is a timing chart which shows the acceleration control at the time of controlling the opening degree of the valve 19. 8A shows the relationship between the accelerator pedal depression amount and time, and FIG. 8B shows the relationship between the opening degree of the throttle valve 7 and the time according to the accelerator pedal depression amount. FIG. 8C shows the relationship between the opening degree of the waste gate valve 19 corresponding to the accelerator pedal depression amount and time, and FIG. 8D shows the relationship between the turbine rotation speed and time. FIG. 8 (e) shows the relationship between the downstream pressure of the throttle valve 7 and time, and FIG. 8 (f) shows that the opening degree of the throttle valve 7 and the waste gate valve 19 is controlled according to the amount of accelerator pedal depression. The relationship between filling efficiency and time is shown. 8C to 8F, the reference acceleration condition among the three conditions is indicated by a solid line as condition 1, and the case where transient correction is not performed on the waste gate valve 19 is indicated by a broken line as condition 2. A case where transient correction is performed on the waste gate valve 19 is indicated by a one-dot chain line as Condition 3.

  FIG. 8A shows that the accelerator pedal depression amount is increased, that is, accelerated between times t1 and t2. When the current torque and the required torque are in the supercharging region, as shown in FIG. 8B, the throttle valve 7 is kept fully open even after the accelerator pedal depression amount is increased. As shown in FIG. 8 (c), in the case of condition 1 and condition 2, the waste gate valve 19 at the end of acceleration (time t2) is closed so that the opening is substantially the same. Is set. On the other hand, in the case of condition 3, the opening degree of the waste gate valve 19 at the time t2 is set closer to the closing side than in the case of condition 1 and condition 2. For this reason, as shown in FIG. 8D, the increase profile of the rotational speed of the turbine 3b in the condition 2 where transient correction is not performed is the rotational speed of the turbine 3b in the condition 1 that is the reference acceleration condition. Compared to the increase profile, the trend is on the decrease side. Further, as shown in FIG. 8E, in the case of condition 2, the downstream pressure of the throttle valve 7 changes significantly on the decrease side as compared with the increase profile of the downstream pressure of the throttle valve 7 in the case of condition 1. To do. As a result, as shown in FIG. 8 (f), the charging efficiency in the case of condition 2 changes on the decrease side compared to the increase profile of the charging efficiency in the case of condition 1, and reaches the target charging efficiency in condition 1. The target charging efficiency is reached at time t4 later than time t3.

  As shown in FIG. 8D, the rotational speed of the turbine 3b in the case of the condition 3 with the transient correction compared with the case without the transient correction as described above (condition 2) is as shown in FIG. It becomes a profile close to the increase profile of the rotational speed of the turbine 3b in the case of a certain condition 1. Further, as shown in FIG. 8E, in the case of condition 3, the downstream pressure of the throttle valve 7 becomes a profile close to the increase profile of the downstream pressure of the throttle valve 7 in the case of condition 1. As a result, as shown in FIG. 8 (f), the filling efficiency in the case of the condition 3 becomes a profile close to the increase profile of the filling efficiency in the case of the condition 1, and therefore the target at the time t3 in the conditions 1 and 3 Reach filling efficiency.

  Therefore, whether the vehicle is accelerating during deceleration of the vehicle shown in FIG. 7 or is further accelerated during acceleration of the vehicle shown in FIG. 8, excessive rotation of the rotational speed of the turbine 3b at the start of acceleration. The fluctuation of the acceleration profile due to can be suppressed. As a result, by controlling the opening degree of the waste gate valve 19, a torque profile corresponding to the driver's acceleration request can be realized.

  The acceleration control process by the ECU 27 according to the first embodiment will be described using the flowchart of FIG. Each process shown in the flowchart of FIG. 9 is performed by the ECU 27 executing a program. This program is stored in a memory (not shown), and is started and executed by the ECU 27 when the ignition switch is turned on.

  In step S601, the required torque is calculated based on the accelerator pedal depression amount by the driver and the rotational speed of the internal combustion engine 1, and the process proceeds to step S602. In step S602, acceleration determination is performed based on the time change rate of the required torque. If the required torque increases with time, that is, if the vehicle is accelerating, an affirmative decision is made in step S602 and the operation proceeds to step S603. If the required torque decreases with time, i.e., if acceleration is not being performed, a negative determination is made in step S602, and the process ends.

  In step S603, it is determined whether the calculated required torque is within the supercharging region. If the requested torque is within the supercharging region, an affirmative determination is made in step S603 and the process proceeds to step S604. If the requested torque is not within the supercharging region, a negative determination is made in step S603 and the process ends. In step S604, the opening degree of the throttle valve 7 is fully opened, and the process proceeds to step S605. In step S605, the target wastegate valve reference opening is calculated as described above, and the process proceeds to step S606. In step S606, the rotational speed of the turbine 3b is detected, and the process proceeds to step S607.

  In step S607, the turbine rotational speed steady convergence value determined by the current rotational speed and torque of the internal combustion engine 1 is calculated as a reference value, and the rotational speed of the turbine 3b at the start of acceleration is compared with the reference value to accelerate. It is determined whether the rotational speed of the turbine 3b at the start is insufficient. If the rotational speed of the turbine 3b is insufficient, that is, if the rotational speed of the turbine 3b at the start of acceleration is less than the reference value, an affirmative determination is made in step S607 and the process proceeds to step S608. In step S608, the target wastegate valve opening amount is calculated by correcting the closing side of the target wastegate valve reference opening amount calculated in step S605, and the processing is terminated.

  If the rotation speed of the turbine 3b is not insufficient, that is, if the turbine rotation speed at the start of acceleration is equal to or higher than the reference value, a negative determination is made in step S607 and the process proceeds to step S609. In step S609, it is determined whether the rotation speed of the turbine 3b is excessive. If the rotational speed of the turbine 3b is excessive, that is, if the rotational speed of the turbine 3b at the start of acceleration exceeds the reference value, an affirmative determination is made in step S609 and the process proceeds to step S610. In step S610, the target wastegate valve opening amount is corrected by performing open-side correction with respect to the target wastegate valve reference opening amount calculated in step S605, and the process ends. When the rotational speed of the turbine 3b is not excessive, that is, when the rotational speed of the turbine 3b at the start of acceleration is equal to the reference value, a negative determination is made in step S609, and the target wastegate valve reference opening calculated in step S605 is determined. The process is terminated without correcting the degree.

According to the engine control apparatus 100 according to the first embodiment described above, the following operational effects are obtained.
(1) The engine control apparatus 100 includes an internal combustion engine having a waste gate valve 19 configured to control a work rate that the turbine receives from the exhaust gas by diverting a part of the exhaust gas from the upstream portion to the downstream portion of the turbine. The engine 1 is controlled. The ECU 27 of the engine control device 100 determines that the waste during the acceleration period increases as the opening degree of the waste gate valve 19 at the start of acceleration increases when the internal combustion engine 1 is accelerated by the same accelerator pedal operation amount from the same rotational speed and the same load. The opening degree of the gate valve 19 is controlled closer to the closing side.

  Furthermore, when the opening degree of the waste gate valve 19 at the start of acceleration is the same when the ECU 27 is accelerated from the same rotational speed and the same load of the internal combustion engine 1 by the same accelerator pedal operation amount, the rotational speed is increased in the supercharging region. The opening degree of the waste gate valve 19 during the acceleration period is controlled closer to the closed side as the engine speed increases and the load decreases, and the rotation speed increases and the load increases in the non-supercharging range. More specifically, the ECU 27 accelerates when the internal combustion engine 1 is accelerated, and a PID steady correction amount calculation unit 711 that controls the opening degree of the waste gate valve 19 according to the required torque in the supercharging region of the internal combustion engine 1. When the rotational speed of the turbine 3b at the start is in a decreasing state, a target W / G opening degree calculation unit 709 that corrects the opening degree of the waste gate valve 19 to the open side is functionally provided. As a result, it is possible to prevent excessive acceleration that occurs when the turbine 3b is accelerated in an excessively rotated state. Therefore, by controlling the opening degree of the waste gate valve 19 under the condition that the internal combustion engine 1 is accelerated by the same accelerator pedal amount from the same rotational speed and the same load, a uniform acceleration profile can be obtained with respect to the charging efficiency. realizable.

  In the prior art, in the supercharging region, the throttle valve is fully opened and the waste gate valve is fully closed as the amount of accelerator pedal depression by the driver increases. FIG. 10 shows acceleration control when a conventional technique is used as a comparative example. FIG. 10A shows the relationship between the accelerator pedal depression amount and time under three different conditions, and FIG. 10B shows the relationship between the opening degree of the throttle valve 7 and the time according to the accelerator pedal depression amount. FIG. 10C shows the relationship between the opening degree of the waste gate valve 19 according to the accelerator pedal depression amount and time, and FIG. 10D shows the opening of the throttle valve 7 and the waste gate valve 19 according to the accelerator pedal depression amount. The relationship between filling efficiency and time by controlling the degree is shown. In FIG. 10, among the three conditions, the case where the accelerator pedal depression amount is the maximum is indicated by a solid line as condition 1, the case where the accelerator pedal depression amount is intermediate is indicated by a broken line as the condition 2, and the accelerator pedal depression amount is the minimum. The case is indicated by a one-dot chain line as Condition 3.

  As shown in FIG. 10 (a), when the accelerator pedal depression amount increases, that is, is accelerated between times t1 and t2, as shown in FIG. 10 (b), as the accelerator pedal depression amount increases, The throttle valve 7 is fully opened. On the other hand, as shown in FIG. 10C, in the case of all the conditions 1 to 3, the opening of the waste gate valve 19 is set to substantially the same opening, that is, the fully closed state at time t2. .

  When the throttle valve 7 and the waste gate valve 19 are controlled as described above, the charging efficiency increases and reaches the target charging efficiency determined based on the accelerator pedal stroke. As shown in FIG. 10D, the target charging efficiency is reached at time t3 in condition 1, at time t4 in condition 2, and at time t5 in condition 3. Then, the opening degree of the waste gate valve 19 is controlled so as to be maintained in the target state at the time when the target charging efficiency is reached, that is, at time t3 in condition 1, at time t4 in condition 2, and at time t5 in condition 3. . In this case, wasteful work due to the turbocharger can be eliminated in the steady state, and the maximum responsiveness of the turbocharger is extracted in the accelerated state. However, as shown in FIG. 10 (d), the period until reaching the target charging efficiency is the same profile even if all the conditions 1 to 3, that is, when the accelerator pedal depression amount is different. It will go through. For this reason, the torque adjustment according to the accelerator pedal depression amount cannot be performed until the target charging efficiency is reached, so that the driver feels uncomfortable with respect to the acceleration performance.

  In contrast to the above comparative example, in the engine control apparatus 100 of the present embodiment, the waste gate valve 19 during the acceleration period is considered in consideration of fluctuations in the acceleration profile due to the difference in opening of the waste gate valve 19 at the start of acceleration. Since the opening degree is controlled, the filling efficiency passes through profiles as shown in FIGS. 7 (f) and 8 (f). As a result, as shown in FIG. 5, it is possible to eliminate the waste work of the turbocharger 3 in the steady state and realize the torque profile according to the accelerator pedal depression amount by the driver during acceleration.

(2) When the internal combustion engine 1 is accelerated, the target W / G opening calculation unit 709 sets the opening of the waste gate valve 19 to the closed side when the rotational speed of the turbine 3b at the start of acceleration is in an increasing state. I corrected it. As a result, it is possible to prevent the shortage of acceleration that occurs when the turbine 3b is accelerated in a state of insufficient rotation. Therefore, by controlling the opening degree of the waste gate valve 19 under the condition that the internal combustion engine 1 is accelerated by the same accelerator pedal amount from the same rotational speed and the same load, a uniform acceleration profile can be obtained with respect to the charging efficiency. realizable.

(3) The ECU 27 functionally includes a turbine rotational speed transient behavior calculating unit 708 that calculates the rotational speed of the turbine 3b at the start of acceleration. Then, the target W / G opening degree calculation unit 709 opens the waste gate valve 19 when the turbine rotation acceleration transient behavior calculation unit 708 estimates that the rotation speed of the turbine 3b at the start of acceleration is in a decreasing state. The degree was corrected to the open side. As a result, it is possible to prevent excessive acceleration that occurs when the turbine 3b is accelerated with excessive rotation. Therefore, by controlling the opening degree of the waste gate valve 19 under the condition that the internal combustion engine 1 is accelerated by the same accelerator pedal amount from the same rotational speed and the same load, a uniform acceleration profile can be obtained with respect to the charging efficiency. realizable.

-Second Embodiment-
An engine control apparatus according to a second embodiment will be described with reference to the drawings. In the following description, the same components as those in the first embodiment are denoted by the same reference numerals, and different points will be mainly described. Points that are not particularly described are the same as those in the first embodiment. In the present embodiment, an increase variation or a decrease variation in the turbocharger state caused by the transient of the internal combustion engine is detected based on a comparison between the turbine rotation speed at the start of acceleration and the steady turbine rotation speed. This is different from the first embodiment.

  FIG. 11 is a functional block diagram schematically illustrating functions of the ECU 27 included in the engine control apparatus 100 according to the second embodiment. The ECU 27 in FIG. 11 functionally includes a steady turbine rotation speed calculation unit 801 and a target turbine rotation profile calculation unit 802 in addition to the functions of the ECU 27 of the first embodiment.

  The steady turbine rotation speed calculation unit 801 calculates the steady turbine rotation speed by map search and interpolation interpolation based on the rotation speed of the internal combustion engine 1 and the target charging efficiency calculation unit 702. It should be noted that the steady turbine rotational speed obtained by adaptation in advance is represented by a two-dimensional map with the rotational speed of the internal combustion engine 1 and the target charging efficiency as axes, and this map is recorded in a predetermined recording area in advance. Yes. When the target turbine rotation profile calculator 802 receives the target turbine rotation speed calculated by the steady turbine rotation speed calculator 801, the target turbine rotation profile calculator 802 calculates a target turbine rotation profile based on the first-order lag transfer function.

  The target W / G opening calculator 709 calculates the target wastegate valve reference opening in the same manner as in the first embodiment. Further, the target W / G opening calculation unit 709 compares the turbine rotation speed with the target turbine rotation profile to calculate the target waste gate valve opening amount. In this case, the target W / G opening calculation unit 709 corrects the target wastegate valve reference opening to the open side when the rotational speed of the turbine 3b at the start of acceleration is larger than the value of the target turbine rotation profile. Then, the target wastegate valve opening amount is calculated. On the other hand, when the rotational speed of the turbine 3b at the start of acceleration is smaller than the value of the target turbine rotation profile, the target W / G opening calculation unit 709 corrects the target wastegate valve reference opening to the closing side. Then, the target wastegate valve opening amount is calculated.

  FIG. 12 shows the relationship between the difference between the rotational speed of the turbine 3b at the start of acceleration and the reference turbine rotational speed, and the correction amount of the opening degree of the waste gate valve 19 during the acceleration period. When the difference between the rotation speed of the turbine 3b at the start of acceleration and the reference turbine rotation speed is a positive value, the rotation of the turbine 3b is in an excessively high state, so that the waste gate valve is used to reduce the rotation speed of the turbine. The opening of 19 is corrected to the open side. When the difference between the rotation speed of the turbine 3b at the start of acceleration and the reference turbine rotation speed is a negative value, the rotation of the turbine 3b is insufficient, that is, the rotation of the turbine 3b is in a transient state. Therefore, the waste gate valve 19 is corrected to the closed side in order to increase the rotational speed of the turbine 3b.

  In the second embodiment, the exhaust gas total energy calculation unit 704, the target turbine work calculation unit 706, the target compressor work calculation unit 707, the turbine rotational speed transient behavior calculation unit 708, and the target W / G ratio calculation unit 709 are also provided. It is not limited to what calculates the rotational speed of the turbine 3b. That is, the same can be obtained by providing a turbine rotation speed sensor and directly detecting the rotation speed of the turbine 3b.

  Also in the second embodiment, the ECU 27 having the above-described configuration performs the process shown in the flowchart of FIG. 9 described in the first embodiment, so that the turbine 3b is insufficiently rotated or excessively rotated at the start of acceleration. The waste gate valve 19 can realize a torque profile according to the driver's acceleration request. As a result, the engine control apparatus 100 according to the second embodiment realizes the acceleration control shown in the timing charts of FIGS. 8 and 9 in the same manner as the engine control apparatus 100 of the first embodiment.

According to the engine control apparatus 100 according to the second embodiment described above, the following functions and effects can be obtained in addition to the functions and effects obtained by the first embodiment.
The ECU 27 functionally includes a steady turbine rotational speed calculation unit 801 that calculates a reference turbine rotational speed based on the rotational speed and load of the internal combustion engine 1. Then, the target W / G opening degree calculation unit 709 controls the opening degree of the waste gate valve 19 to be more open as the rotation speed of the turbine 3b at the start of acceleration is larger than the calculated reference turbine rotation speed. I made it. As a result, it is possible to suppress fluctuations in the acceleration profile due to insufficient rotation or excessive rotation of the turbine 3b at the start of acceleration, and to realize a torque profile according to the driver's acceleration request. Furthermore, it is possible to adjust the acceleration with respect to the accelerator pedal stroke by using the turbine rotation profile as a design parameter.

-Third embodiment-
An engine control apparatus according to a third embodiment will be described with reference to FIGS. In the following description, the same components as those in the second embodiment are denoted by the same reference numerals, and different points will be mainly described. Points that are not particularly described are the same as those in the first and second embodiments. In the present embodiment, the operation mode of the internal combustion engine can be switched between the acceleration priority mode and the fuel efficiency priority mode by cooperative control of the throttle valve and the waste gate valve. The first and second implementations are such that the opening degree of the throttle valve and the waste gate valve is controlled in consideration of the change in the state of the turbocharger at the start of acceleration caused by the switching control. The form is different.

  First, switching control between the acceleration priority mode and the fuel efficiency priority mode by cooperative control of the throttle valve 7 and the waste gate valve 19 will be described with reference to FIG. FIG. 13A is a diagram illustrating a trade-off relationship between fuel efficiency performance and acceleration performance. As shown in FIG. 13A, in the acceleration-oriented mode, the acceleration performance is improved, but the fuel efficiency is deteriorated, that is, the rotational speed of the turbine 3b and the pump loss are increased. Further, in the fuel efficiency mode, the fuel efficiency is improved, but the acceleration performance is deteriorated, that is, the rotational speed of the turbine 3b and the pump loss are reduced. When switching between the acceleration priority mode and the fuel efficiency priority mode having the trade-off relationship as described above, the throttle valve 7 and the waste gate valve 19 are opened under the same rotation speed and load conditions of the internal combustion engine 1. Change the combination of degrees. As a result, the acceleration performance and the fuel consumption performance can be changed along the line indicated by the broken line in FIG.

FIG. 13B is a diagram showing the relationship of the target throttle valve opening degree with respect to the acceleration priority mode and the fuel efficiency priority mode. As shown in FIG. 13B, the opening degree of the throttle valve 7 is set to the open side as the fuel efficiency is emphasized. As the acceleration performance is more important, the opening degree of the throttle valve 7 is set to the close side. FIG. 13C is a diagram showing the relationship of the target wastegate valve opening amount with respect to the acceleration priority mode and the fuel efficiency priority mode. As shown in FIG. 13C, the opening degree of the waste gate valve 19 is set to the open side as the fuel efficiency is more important. As the acceleration performance is more important, the opening degree of the waste gate valve 19 is set to the close side. In the present embodiment, by considering the relationship shown in FIGS. 13B and 13C and the relationship shown in the target throttle valve opening map and the target wastegate valve opening map shown in FIG. The operation mode of the internal combustion engine 1 is switched between the acceleration priority mode and the fuel efficiency priority mode. Details will be described below.

  FIG. 14 is a block diagram schematically illustrating functions of the ECU 27 according to the third embodiment. The ECU 27 of FIG. 14 functionally includes a fuel efficiency-oriented / acceleration-oriented operation mode switching unit 901 in addition to the functions of the ECU 27 of the second embodiment.

  The fuel-consumption-oriented / acceleration-oriented operation mode switching unit 901 is based on the fuel economy-oriented mode and acceleration-oriented based on the rotational speed of the internal combustion engine 1, the requested torque calculated by the requested torque calculating unit 701, and the transmission setting state. The operation mode of the internal combustion engine 1 is switched between the modes. The fuel economy-oriented / acceleration-oriented operation mode switching unit 901 uses, for example, the transient frequency of the internal combustion engine 1 as the operation mode selection criterion when switching the operation mode. The fuel consumption-oriented / acceleration-oriented driving mode switching unit 901 switches the driving mode to the fuel efficiency-oriented mode when it is determined that the transient frequency is small, and when it is determined that the transient frequency is large, the driving mode is changed to the acceleration-oriented mode. Switch.

  The target throttle valve opening calculator 703 calculates the target throttle valve opening in the same manner as in the first and second embodiments. Then, the target throttle valve opening calculation unit 703 corrects the calculated target throttle valve opening in accordance with the operation mode switched by the fuel efficiency-oriented / acceleration-oriented operation mode switching unit 901. In this case, the target throttle valve opening calculation unit 703 corrects the calculated target throttle valve opening based on FIG. Then, the target throttle valve opening calculator 703 outputs the corrected target throttle valve opening as a throttle valve opening command value.

  The target W / G ratio calculation unit 705 calculates the target waste gate ratio in the same manner as in the first and second embodiments. Then, the target W / G ratio calculation unit 705 corrects the calculated target waste gate ratio in accordance with the operation mode switched by the fuel efficiency-oriented / acceleration-oriented operation mode switching unit 901. In other words, the target W / G ratio calculation unit 705 corrects the calculated target waste gate ratio based on FIG. Then, the target W / G ratio calculation unit 705 outputs the corrected target waste gate ratio to the target turbine work calculation unit 706.

  The steady turbine rotational speed calculation unit 801 calculates the steady turbine rotational speed in the same manner as in the second embodiment. Then, the steady turbine rotation speed calculation unit 801 corrects the calculated steady turbine rotation speed in accordance with the operation mode switched by the fuel efficiency-oriented / acceleration-oriented operation mode switching unit 901, and then proceeds to the target turbine rotation profile calculation unit 802. Output. The target turbine rotation profile calculator 802 calculates the target turbine rotation profile in the same manner as in the second embodiment. Then, the target turbine rotation profile calculation unit 802 corrects the calculated target turbine rotation profile according to the operation mode switched by the fuel efficiency-oriented / acceleration-oriented operation mode switching unit 901. In this case, the target turbine rotation profile calculation unit 802 sets the time constant to a smaller side as the acceleration is more important in the first-order lag transfer function used when calculating the target turbine rotation profile. The target steady supercharging pressure calculation unit 710 calculates the target steady supercharging pressure in the same manner as in the first and second embodiments, and the operation switched by the fuel efficiency-oriented / acceleration-oriented operation mode switching unit 901. The calculated target steady supercharging pressure is corrected according to the mode.

  FIG. 15 shows the change in the state of the turbocharger 3 at the start of acceleration caused by the ECU 27 switching control of the operation mode of the internal combustion engine 1 by cooperative control according to the third embodiment. 7 is a timing chart showing acceleration control when the opening degree of the throttle valve 7 and the waste gate valve 19 is controlled. FIG. 15A shows the relationship between the accelerator pedal depression amount and time, and FIG. 15B shows the relationship between the opening degree of the throttle valve 7 and the time according to the accelerator pedal depression amount. FIG. 15C shows the relationship between the opening degree of the waste gate valve 19 corresponding to the accelerator pedal depression amount and time, and FIG. 15D shows the relationship between the turbine rotation speed and time. FIG. 15 (e) shows the relationship between the downstream pressure of the throttle valve 7 and time, and FIG. 15 (f) shows the filling due to the opening degree of the throttle valve 7 and the waste gate valve 19 being controlled in accordance with the accelerator pedal stroke. It shows the relationship between efficiency and time. 15 (c) to 15 (f), the reference acceleration condition among the three conditions is indicated by a solid line as condition 1, and the case where transient correction is not performed on the waste gate valve 19 is indicated by a broken line as condition 2. A case where transient correction is performed on the waste gate valve 19 is indicated by a one-dot chain line as Condition 3.

  FIG. 15A shows that the accelerator pedal depression amount is increased, that is, accelerated during the period from time t1 to time t2. When it is determined that the required torque is in the supercharging region, as shown in FIG. 15B, the throttle valve 7 is fully opened according to the amount of depression of the accelerator pedal. As shown in FIG. 15C, in the case of Condition 1 and Condition 2, the waste gate valve 19 at the end of acceleration (time t2) is closed so that the opening is substantially the same. Is set. On the other hand, in the case of condition 3, the opening degree of the waste gate valve 19 at time t2 is set to be more open than in the case of condition 1 and condition 2. For this reason, as shown in FIG. 15 (d), the increase profile of the turbine rotation speed in the condition 2 where the transient correction is not performed is compared with the increase profile of the turbine rotation speed in the condition 1 which is the reference acceleration condition. Therefore, it will increase remarkably. Further, as shown in FIG. 15E, in the case of condition 2, the downstream pressure increase profile of the throttle valve 7 is remarkably compared with the increase profile of the downstream pressure of the throttle valve 7 in the case of condition 1. It will increase on the increase side. As a result, as shown in FIG. 15 (f), the charging efficiency in the case of the condition 2 changes on the increase side as compared with the increase profile of the charging efficiency in the case of the condition 1, and becomes the target charging efficiency in the condition 1. The target charging efficiency is reached at time t3 earlier than time t4.

  Compared with the case where the transient correction is not performed as described above (condition 2), the turbine rotation speed in the case of condition 3 where the transient correction is performed is the condition that is the reference acceleration condition as shown in FIG. It becomes a profile close to the increase profile of the turbine rotational speed in the case of 1. Further, as shown in FIG. 15E, in the case of condition 3, the downstream pressure of the throttle valve 7 substantially matches the increase profile of the downstream pressure of the throttle valve 7 in the case of condition 1. As a result, as shown in FIG. 15 (f), the filling efficiency in the case of the condition 3 substantially matches the increase profile of the filling efficiency in the case of the condition 1, and therefore the target filling at the time t4 in the conditions 1 and 3 Reach efficiency.

  The acceleration control process by the ECU 27 of the third embodiment will be described using the flowchart of FIG. Each process shown in the flowchart of FIG. 16 is performed by the ECU 27 executing a program. This program is stored in a memory (not shown), and is activated and executed by the ECU 17.

  Step S801 (required torque calculation) is the same process as step S601 (required torque calculation) in FIG. In step S802, the operation mode of the internal combustion engine 1 is switched between the fuel efficiency priority mode and the acceleration priority mode based on information such as the time change history of the required torque and the state of the transmission, and the process proceeds to step S803. Each process from step S803 (acceleration determination) to step S811 (waste gate valve opening side correction) is the same as each process from step S602 (acceleration determination) to step S610 (waste gate valve opening side correction) in FIG. is there.

According to the engine control apparatus 100 according to the above-described third embodiment, the following functions and effects can be obtained in addition to the functions and effects obtained by the first and second embodiments.
The ECU 72 switches the operation mode of the internal combustion engine 1 between a mode that emphasizes acceleration and a mode that emphasizes fuel efficiency by a combination of the opening of the throttle valve 7 and the opening of the waste gate valve 19. Emphasis / acceleration emphasis operation mode switching unit 901 is functionally provided. Then, the target W / G opening calculation unit 709 corrects the target waste gate valve opening amount of the waste gate valve 19 based on the operation mode switched by the fuel consumption-oriented / acceleration-oriented operation mode switching unit 901. . As a result, when realizing a uniform acceleration profile under the intermediate acceleration condition with the same accelerator pedal depression amount from the same rotational speed and the same load condition of the internal combustion engine 1, it is possible to set the intermediate acceleration profile according to the operation mode. it can.

The engine control apparatus 100 according to the third embodiment described above can be modified as follows.
The switching of the operation mode of the internal combustion engine 1 by the fuel consumption priority / acceleration priority operation mode switching unit 901 is not limited to that based on the rotational speed of the internal combustion engine 1, the required torque, and the transmission setting state. For example, the fuel consumption-oriented / acceleration-oriented operation mode switching unit 901 may switch the operation mode of the internal combustion engine 1 in accordance with a switch operation by the driver. When the vehicle has a lower bound recognition system such as a camera, the fuel efficiency / acceleration focus operation mode switching unit 901 estimates the necessity of the transient frequency of the internal combustion engine 1 based on the output from the lower bound recognition system, The operation mode of the internal combustion engine 1 may be switched according to the estimation result. That is, as described above, the fuel efficiency-oriented / acceleration-oriented operation mode switching unit 901 may set the fuel efficiency-oriented mode when it is estimated that the transient frequency is small, and may set the acceleration-oriented mode when it is estimated that the transient frequency is large. . Furthermore, when the vehicle includes a navigation device, the fuel efficiency-oriented / acceleration-oriented driving mode switching unit 901 uses the map information of the navigation device to estimate the necessity of transient frequency, and according to the estimation result, The operation mode of the internal combustion engine 1 may be switched.

-Fourth embodiment-
An engine control apparatus according to a fourth embodiment will be described with reference to FIGS. In the following description, the same components as those in the second embodiment are denoted by the same reference numerals, and different points will be mainly described. Points that are not particularly described are the same as those in the first and second embodiments. In the present embodiment, the internal combustion engine has a Cooled-EGR system, and the throttle valve and the waste gate valve are considered in consideration of fluctuations in the state of the turbocharger at the start of acceleration caused by the difference in the Cooled-EGR amount. This is different from the first and second embodiments in that it controls the opening degree.

  The operation region in which the internal combustion engine 1 having the Cooled-EGR system introduces the Cooled-EGR will be described with reference to FIG. FIG. 17 is a two-dimensional map of the rotation speed and charging efficiency of the internal combustion engine 1. In the present embodiment, in the region surrounded by the broken line in FIG. 17, that is, in the relatively high load region of the supercharged region and the non-supercharged region, instead of the rich control conventionally performed in this region, Cooled- Perform stoichiometric combustion while introducing EGR. As a result, damage to the turbine 3b due to knock reduction and exhaust temperature control is prevented while eliminating wasteful fuel consumption.

FIG. 18 is a diagram showing the relationship between the charging efficiency and the opening degree of the waste gate valve 19, the downstream pressure of the throttle valve 7, and the rotational speed of the turbine 3b by introducing the Cooled-EGR system as described above. It is. FIG. 18 (a) shows the relationship between the opening degree of the waste gate valve 19 and the charging efficiency when Cooled-EGR is introduced when the rotational speed and load of the internal combustion engine 1 are fixed. In FIG. 18A, the case where Cooled-EGR is introduced is indicated by a solid line, and the case where Cooled-EGR is not introduced is indicated by a broken line. As shown in FIG. 18A, the waste gate valve 19 needs to be corrected to the close side as the introduction ratio of Cooled-EGR is increased.

  FIG. 18B shows the relationship between the downstream pressure of the throttle valve 7 and the charging efficiency when Cooled-EGR is introduced when the rotational speed and load of the internal combustion engine 1 are fixed. In FIG. 18B, the case where Cooled-EGR is introduced is indicated by a solid line, and the case where Cooled-EGR is not introduced is indicated by a broken line. As shown in FIG. 18B, the downstream pressure of the throttle valve 7 increases as the introduction ratio of Cooled-EGR increases. FIG. 18C shows the relationship between the rotational speed of the turbine 3b and the charging efficiency when Cooled-EGR is introduced when the rotational speed and load of the internal combustion engine 1 are fixed. In FIG. 18C, the case where Cooled-EGR is introduced is indicated by a solid line, and the case where Cooled-EGR is not introduced is indicated by a broken line. As shown in FIG. 18C, the rotational speed of the turbine 3b increases as the introduction ratio of Cooled-EGR increases. In the present embodiment, the relationship shown in the steady target map shown in FIG. 4 and the influence of the introduction of the Cooled-EGR system as shown in FIG. 18 are taken into consideration, thereby supporting the Cooled-EGR system. .

  FIG. 19 is a block diagram schematically illustrating functions of the ECU 27 according to the fourth embodiment. The ECU 27 in FIG. 19 functionally includes a target EGR rate calculation unit 1001 and a target EGR valve opening calculation unit 1002 in addition to the functions of the ECU 27 of the second embodiment. The target EGR rate calculation unit 1001 calculates a target EGR rate by map search and interpolation interpolation based on the rotation speed of the internal combustion engine 1 and the target charging efficiency calculated by the target charging efficiency calculation unit 702. Then, the target EGR rate calculation unit 1001 corrects the calculated target EGR rate based on the state determination result determined by the cooling water temperature of the internal combustion engine 1. Note that the target EGR rate obtained by adaptation in advance is represented on a two-dimensional map with the rotational speed of the internal combustion engine 1 and the target charging efficiency as axes, and this map is recorded in a predetermined recording area in advance.

The target EGR valve opening calculation unit 1002 calculates the target EGR valve opening by map search and interpolation interpolation based on the rotational speed of the internal combustion engine 1 and the calculated target charging efficiency. Then, the target EGR valve opening calculation unit 1002 corrects the calculated target EGR valve opening based on the target EGR rate calculated by the target EGR rate calculation unit 1001. The target EGR valve opening calculator 1002 outputs the corrected target EGR valve opening as an EGR valve opening command value to the EGR valve 24 to control the opening of the EGR valve 24. Note that the target EGR valve opening determined by adaptation in advance is represented on a two-dimensional map with the rotational speed of the internal combustion engine 1 and the target charging efficiency as axes, and this map is recorded in a predetermined recording area in advance. Yes.

  The target throttle valve opening calculator 703 calculates the target throttle valve opening in the same manner as in the first and second embodiments. Then, the target throttle valve opening calculation unit 703 corrects the calculated target throttle valve opening based on the target EGR rate calculated by the target EGR rate calculation unit 1001, and uses the throttle valve opening command value as a throttle valve opening command value. 7 is output. The exhaust gas total energy calculation unit 704 corrects the total energy of the exhaust gas calculated in the same manner as in the first and second embodiments based on the target EGR rate calculated by the target EGR rate calculation unit 1001. .

  The target W / G ratio calculation unit 705 corrects the target waste gate ratio calculated in the same manner as in the first and second embodiments based on the target EGR rate calculated by the target EGR rate calculation unit 1001. To do. The steady turbine rotation speed calculation unit 801 corrects the steady turbine rotation speed calculated in the same manner as in the second embodiment based on the target EGR rate calculated by the target EGR rate calculation unit 1001. The target steady supercharging pressure calculation unit 710 corrects the target steady supercharging pressure calculated in the same manner as in the second embodiment based on the target EGR rate calculated by the target EGR rate calculation unit 1001.

  FIG. 20 shows the throttle valve 7 and the waste gate valve 19 in consideration of fluctuations in the state of the turbocharger 3 at the start of acceleration caused by the ECU 27 according to the fourth embodiment due to the difference in the Cooled-EGR amount. It is a timing chart which shows the acceleration control at the time of controlling the opening degree. 20A shows the relationship between the accelerator pedal depression amount and time, and FIG. 20B shows the relationship between the opening degree of the throttle valve 7 and the EGR valve 24 corresponding to the accelerator pedal depression amount and time. FIG. 20C shows the relationship between the opening degree of the waste gate valve 19 corresponding to the accelerator pedal depression amount and time, and FIG. 20D shows the relationship between the turbine rotation speed and time. FIG. 20 (e) shows the relationship between the downstream pressure of the throttle valve 7 and time, and FIG. 20 (f) shows the filling due to the opening degree of the throttle valve 7 and the waste gate valve 19 being controlled according to the amount of accelerator pedal depression. It shows the relationship between efficiency and time. FIG. 20G shows the relationship between the change in the EGR rate according to the opening degree of the EGR valve 24 and time. 20 (b) to (f), the reference acceleration condition among the three conditions is indicated by a solid line as condition 1, and the case where no transient correction is performed on the waste gate valve 19 is indicated by a broken line as condition 2. A case where transient correction is performed on the waste gate valve 19 is indicated by a one-dot chain line as Condition 3.

  FIG. 20A shows that the accelerator pedal depression amount is increased, that is, accelerated during the period from time t1 to time t2. When it is determined that the required torque is in the supercharging region, as shown in FIG. 20B, the throttle valve 7 is fully opened according to the amount of depression of the accelerator pedal. Further, the EGR valve 24 is fully closed so that the introduction of EGR is stopped under the acceleration condition. As a result, as shown in FIG. 20 (g), the EGR rate becomes the target EGR rate at time t2. As shown in FIG. 20 (c), in the case of condition 1 and condition 2, the waste gate valve 19 at the end of acceleration (time t2) is closed so that the opening is substantially the same. Is set. On the other hand, in the case of condition 3, the opening degree of the waste gate valve 19 at time t2 is set to be more open than in the case of condition 1 and condition 2. For this reason, as shown in FIG. 20 (d), the increase profile of the turbine rotation speed in the condition 2 where the transient correction is not performed is compared with the increase profile of the turbine rotation speed in the condition 1 which is the reference acceleration condition. Therefore, it will increase remarkably. Furthermore, as shown in FIG. 20 (e), in the case of condition 2, the increase profile of the downstream pressure of the throttle valve 7 is remarkably compared with the increase profile of the downstream pressure of the throttle valve 7 in the case of condition 1. It will increase on the increase side. As a result, as shown in FIG. 20 (f), the charging efficiency in the case of the condition 2 changes on the increase side as compared with the increase profile of the charging efficiency in the case of the condition 1, and becomes the target charging efficiency in the condition 1. The target charging efficiency is reached at time t3 earlier than time t4.

  Compared with the case where the transient correction is not performed as described above (condition 2), the turbine rotational speed in the condition 3 where the transient correction is performed is the condition that is the reference acceleration condition as shown in FIG. It becomes a profile close to the increase profile of the turbine rotational speed in the case of 1. Further, as shown in FIG. 20E, in the case of condition 3, the downstream pressure of the throttle valve 7 substantially matches the increase profile of the downstream pressure of the throttle valve 7 in the case of condition 1. As a result, as shown in FIG. 20 (f), the filling efficiency in the case of the condition 3 substantially coincides with the increase profile of the filling efficiency in the case of the condition 1. Therefore, in the conditions 1 and 3, the target filling is performed at the time t4. Reach efficiency.

  The acceleration control process by the ECU 27 of the third embodiment will be described using the flowchart of FIG. Each process shown in the flowchart of FIG. 21 is performed by executing a program by the ECU 27. This program is stored in a memory (not shown), and is activated and executed by the ECU 17.

  Step S901 (required torque calculation) is the same process as step S601 (required torque calculation) in FIG. In step S902, the state of the internal combustion engine 1 is determined based on information such as the coolant temperature of the internal combustion engine 1, and the process proceeds to step S903. Each processing from step S903 (acceleration determination) to step S905 (setting of throttle fully open) is the same as each processing from step S602 (acceleration determination) to step S604 (setting of throttle full open) in FIG.

  In step S906, the opening degree of the EGR valve 24 is controlled so that the EGR rate is set according to the rotation speed and required torque of the internal combustion engine 1, and the process proceeds to step S907. Each processing from Step S907 (Wastegate valve reference opening calculation) to Step S912 (Wastegate valve opening side correction) is performed from Step S605 (Wastegate valve reference opening calculation) to Step S610 (Wastegate valve opening) in FIG. (Side correction).

According to the engine control apparatus according to the fourth embodiment described above, the following functions and effects are obtained in addition to the functions and effects obtained by the first and second embodiments.
The ECU 27 switches the operation mode of the internal combustion engine 1 between a mode for introducing EGR and a mode for prohibiting the introduction of EGR. The target W / G opening degree calculation unit 709 corrects the opening degree of the waste gate valve 19 based on whether or not EGR is introduced. As a result, fluctuations in the acceleration profile due to excessive rotation of the rotation speed of the turbine 3b at the start of acceleration due to the introduction of EGR can be suppressed, and the torque profile corresponding to the driver's acceleration request can be realized by the waste gate valve 19.

  As long as the characteristics of the present invention are not impaired, the present invention is not limited to the above-described embodiments, and other forms conceivable within the scope of the technical idea of the present invention are also included in the scope of the present invention. .

1 internal combustion engine, 2 intake air temperature sensor,
3 turbocharger, 3a compressor,
3b turbine, 4 air bypass valve,
5 Intercooler, 6 Temperature sensor,
7 throttle valve, 8 intake manifold,
9 Pressure sensor, 10 Flow enhancement valve,
11 intake variable valve mechanism, 12 intake variable valve position sensor,
13 Exhaust variable valve mechanism, 14 Exhaust variable valve position sensor,
15 fuel injection valve, 16 spark plug,
17 Knock sensor, 18 Crank angle sensor,
19 waste gate valve, 20 air-fuel ratio sensor,
21 exhaust purification catalyst, 22 EGR pipe,
23 EGR cooler, 24 EGR valve,
25 temperature sensor, 26 differential pressure sensor,
27 ECU, 100 engine control device,
701 required torque calculation unit, 702 target filling efficiency calculation unit,
703 target throttle valve opening calculation unit, 704 exhaust gas total energy calculation unit,
705 target W / G ratio calculation unit, 706 target turbine work calculation unit,
707 Target compressor work calculation unit, 708 Turbine rotational speed transient behavior calculation unit,
709 Target W / G opening calculation unit, 710 Target steady supercharging pressure calculation unit,
711 PID steady correction amount calculation unit, 801 steady turbine rotational speed calculation unit,
802 Target turbine rotation profile calculation unit,
901 Fuel consumption priority / acceleration priority driving mode switching unit,
1001 Target EGR rate calculation unit 1002 Target EGR valve opening calculation unit

Claims (2)

A control device for an internal combustion engine comprising a wastegate valve configured to be able to control the power that the turbine receives from the exhaust gas by diverting a part of the exhaust gas from the upstream portion to the downstream portion of the turbine,
When accelerating at the same rotational speed and the same accelerator operation amount from the same load of the internal combustion engine, the larger the opening degree of the waste gate valve at the start of acceleration, the closer the opening degree of the waste gate valve during the acceleration period to the closed side. A control device for an internal combustion engine, comprising an opening degree control unit for controlling. A control device for an internal combustion engine comprising a wastegate valve configured to be able to control the power that the turbine receives from the exhaust gas by diverting a part of the exhaust gas from the upstream portion to the downstream portion of the turbine,
When the internal combustion engine is accelerated by the same accelerator operation amount from the same rotational speed and the same load, when the opening degree of the waste gate valve at the start of acceleration is the same, the higher the rotational speed and the smaller the load in the supercharging region. An internal combustion engine control device comprising: an opening degree control unit that controls the opening degree of the waste gate valve during the acceleration period closer to a closed side as the rotational speed is larger and the load is larger in the non-supercharging region .

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