JP2023116004A - Internal combustion engine control system - Google Patents

Abstract

An object of the present invention is to provide an internal combustion engine control system that can efficiently operate an internal combustion engine by combining control of a waste gate valve and control of a rotating electrical machine according to the state of a vehicle. A control system for an internal combustion engine includes: a turbine through which exhaust gas from an internal combustion engine mounted on a vehicle flows; a compressor disposed coaxially with the turbine and supercharging intake air of the internal combustion engine; It includes a rotating electrical machine that rotates a compressor, a wastegate valve that adjusts the amount of exhaust gas flowing into the turbine, and a control device that controls the rotating electrical machine and the wastegate valve. The control device generates power with the rotating electrical machine while controlling either the rotating electrical machine or the waste gate valve with priority, depending on the state of the vehicle. [Selection diagram] Figure 1

Description

The present disclosure relates to control systems for internal combustion engines.

BACKGROUND ART Conventionally, an electric supercharger is known in which a motor (rotary electric machine) is attached to a supercharger having a turbine and a compressor (see, for example, Patent Documents 1 and 2). Such an electric supercharger assists the rotation of the turbine with a rotating electrical machine to control the rotation speed of the turbine.

Patent Literature 1 discloses a control system for an internal combustion engine that regenerates and controls a rotating electrical machine using exhaust energy recovered by a turbine in an internal combustion engine that uses such an electric supercharger. Patent Literature 2 discloses a control system for an internal combustion engine that increases the output of the internal combustion engine when electric power is generated by a rotating electrical machine.

JP-A-2005-83222 JP-A-2004-169673

In such an electric supercharger, it is preferable to control a combination of a waste gate valve that adjusts the exhaust energy flowing to the turbine and regeneration or power running of the motor. Patent Document 1 and Patent Document 2 do not disclose this point.

An object of the present disclosure is to provide an internal combustion engine control system capable of efficiently operating the internal combustion engine by combining control of the wastegate valve and control of the rotating electric machine according to the state of the vehicle.

A control system for an internal combustion engine according to the present disclosure includes a turbine through which exhaust gas from an internal combustion engine mounted in a vehicle flows, a compressor arranged coaxially with the turbine for supercharging intake air of the internal combustion engine, the turbine, and A rotating electrical machine that rotates a compressor, a wastegate valve that adjusts the amount of exhaust gas flowing to the turbine, and a control device that controls the rotating electrical machine and the wastegate valve. The control device preferentially controls one of the rotating electric machine and the waste gate valve according to the state of the vehicle, and generates electric power with the rotating electric machine.

According to this internal combustion engine control system, one of the rotating electric machine and the waste gate valve is preferentially controlled according to the state of the vehicle. As a result, the control system of the internal combustion engine controls the number of revolutions of the turbine according to the state of the vehicle, and generates electric power using the rotating electric machine. As a result, the internal combustion engine can operate efficiently.

According to the present disclosure, it is possible to provide an internal combustion engine control system capable of efficiently operating the internal combustion engine by combining the control of the wastegate valve and the control of the rotating electric machine according to the state of the vehicle.

1 is a system diagram of an internal combustion engine control system according to an embodiment of the present disclosure; FIG. 4 is a flow chart showing a control procedure of the control device according to the embodiment of the present disclosure; FIG. 2 is a diagram showing a regeneration region and a power generation region in a graph showing output (torque) and rotation speed of an internal combustion engine according to an embodiment of the present disclosure; 4 is a timing chart showing the turbine speed, the opening of the wastegate valve, and the operating state of the motor generator when the vehicle accelerates and decelerates according to the embodiment of the present disclosure;

Hereinafter, embodiments of the present disclosure will be described with reference to the drawings.

As shown in FIG. 1, an internal combustion engine control system 1 includes an engine (an example of an internal combustion engine) 2, a turbine 4, a compressor 6, a motor generator (an example of a rotating electrical machine) 8, a waste gate valve 10, A power storage device 12 , a throttle valve 14 , an accelerator position sensor 16 , a catalyst device 18 , and a control device 20 are provided.

The internal combustion engine 2 of this embodiment is mounted on a vehicle such as an automobile, and includes a cylinder 2a, a piston 2b that slides in the cylinder 2a, an injector 2c that injects fuel, and a spark plug 2d that ignites the air-fuel mixture. It is a reciprocating gasoline internal combustion engine. In this embodiment, the internal combustion engine 2 is a serial internal combustion engine 2 in which the cylinders 2a are arranged in a row. Further, the internal combustion engine 2 of this embodiment is a direct injection internal combustion engine that directly injects fuel into the cylinder 2a.

The exhaust gas discharged from the cylinder 2 a of the internal combustion engine 2 flows through the turbine 4 . The turbine 4 is covered by a turbine housing 4a and is rotated by exhaust energy flowing into the turbine housing 4a.

Compressor 6 is arranged on rotating shaft 4 b connected to turbine 4 . The compressor 6 is covered with a compressor housing 6a and supercharges the intake air of the internal combustion engine 2 supplied from the air cleaner 22 to the compressor housing 6a. A downstream side of the compressor 6 is connected to an intake passage 24 that is connected to an intake port of the internal combustion engine 2 . An intercooler 26 is arranged on the intake passage 24 to cool the supercharged intake air. A throttle valve 14 is arranged downstream of the intercooler 26 in the intake passage 24 . The throttle valve 14 is electrically connected to the control device 20 and controls the amount of intake air supplied to the internal combustion engine 2 .

The motor generator 8 has an output shaft coupled to the rotating shaft 4b of the turbine 4, and rotates the turbine 4 and the compressor 6 by power running. In this embodiment, the rotating shaft 4b is the output shaft of the motor generator 8. As shown in FIG. The motor generator 8 has a regeneration circuit, and can be regenerated by applying a load to the regeneration circuit. The motor generator 8 can reduce the rotational speeds of the turbine 4 and the compressor 6 by regenerating, which is called regenerative charge control. Furthermore, the motor-generator 8 can also generate power without lowering the rotational speed of the turbine 4 while the rotating shaft 4b is being driven by the turbine 4, which is called power generation charge control. In other words, the motor generator 8 can also recover exhaust energy by the turbine 4 and generate electric power. In this specification, regeneration (regenerative charge control) refers to regeneration for the purpose of reducing the turbine speed. Also, the case of regenerating for the purpose of charging the power storage device 12 is referred to as power generation (power generation charge control).

Motor generator 8 is electrically connected to power storage device 12 . Power storage device 12 discharges electric power and supplies electric power to motor generator 8 when motor generator 8 is powered. On the other hand, power storage device 12 receives and stores electric power when motor generator 8 regenerates and generates electric power. In this embodiment, the power storage device 12 is composed of a lithium-ion battery, a Ni-Cd battery, or the like. However, the power storage device 12 may be any device as long as it can store and discharge electric power, and may be a capacitor or the like, for example.

The wastegate valve 10 is a device that adjusts the amount of exhaust gas flowing to the turbine 4 . Specifically, a wastegate passage 10a is provided that bypasses the turbine 4 from the turbine housing 4a and is connected to the exhaust passage 28, and the wastegate valve 10 is a valve that opens and closes the wastegate passage 10a. The wastegate valve 10 is used to increase or decrease the turbine rotation speed Tr of the turbine 4 by adjusting the amount of exhaust gas flowing through the turbine 4 . When the turbine rotation speed Tr of the turbine 4 changes, the supercharging pressure Pr rises and falls. Therefore, by controlling the opening W of the waste gate valve 10, the supercharging pressure Pr can be controlled. The wastegate valve 10 of this embodiment is an electromagnetic valve that is operated to open and close by an electric actuator. Further, the wastegate valve 10 of the present embodiment is a normally open type wastegate valve 10 that opens the wastegate passage 10a in an uncontrolled state.

The control device 20 is a device that preferentially controls either the motor generator 8 or the waste gate valve 10 according to the state of the vehicle, and controls the turbine rotation speed Tr of the turbine 4 . In this embodiment, the control device 20 detects the accelerator opening Th from an accelerator position sensor 16 attached to an accelerator pedal 16a, and controls the injector 2c, the motor generator 8, the waste gate valve 10, etc. according to the accelerator opening Th. Control of each device of the control system of the internal combustion engine 2 is executed. The control device 20 is actually an ECU (Electronic Control Unit) configured by a microcomputer including an arithmetic device, a memory, an input/output buffer, and the like. The control device 20 controls each device based on the map and program stored in the memory so that the internal combustion engine 2 is in a desired operating state. Various controls are not limited to processing by software, and can be processed by dedicated hardware (electronic circuits).

More specifically, the control device 20 of the present embodiment acquires the accelerator opening Th, determines a required output (torque) ETq required of the internal combustion engine 2, and calculates a target output (torque) ETq corresponding to the required output (torque) ETq. Determine boost pressure Pt. The controller 20 acquires the actual boost pressure Pr from the atmospheric pressure sensor 32 attached to the air cleaner 22 and the pressure sensor 34 attached to the intake passage 24, and adjusts the boost pressure Pr to the target boost pressure Pt. , control of power running and regeneration of the motor generator 8 and control of the opening W of the waste gate valve 10 are executed. The control device 20 controls the turbine rotation speed Tr of the turbine 4 by controlling the motor generator 8 and the wastegate valve 10 in this manner.

Note that the accelerator opening Th is an example of the state of the vehicle. The state of the vehicle may also be the acceleration/deceleration state of the vehicle acquired from an acceleration sensor (not shown).

Next, the control procedure executed by the control device 20 will be described with reference to the flow chart of FIG. 2 and FIGS. 3 and 4 . The control device 20 starts a control procedure when an ignition switch (not shown) is turned on.

Steps S1 to S3 will be described as an example of the state of the vehicle that is accelerated near the maximum output of the internal combustion engine 2 as indicated by arrow A in FIG. In step S1, the control device 20 detects the accelerator opening Th. The control device 20 determines the target supercharging pressure Pt according to the accelerator opening Th. In this embodiment, the target supercharging pressure Pt is determined as the maximum supercharging pressure. The maximum supercharging pressure is a value determined by the size of the turbine 4 and the supercharging capacity of the compressor 6 . Therefore, the maximum supercharging pressure is a value that can be appropriately changed according to the turbine 4 and compressor 6 .

The control device 20 closes the waste gate valve 10 and executes control to power-run the motor generator 8 so that the boost pressure Pr becomes the target boost pressure Pt. When the controller 20 controls in this manner, the turbine rotation speed Tr increases as shown from time t0 to time t1 in FIG. 4, and finally the supercharging pressure Pr reaches near the target supercharging pressure Pt.

When the controller 20 determines that the supercharging pressure Pr has reached the vicinity of the target supercharging pressure Pt (step S2), it controls the motor generator 8 with priority over the waste gate valve 10 (step S3). Specifically, the control device 20 determines the turbine rotation speed Tr at which the target supercharging pressure Pt is reached as the target turbine rotation speed Trt. The control device 20 regenerates the motor generator 8 so that the turbine rotation speed Tr becomes the target turbine rotation speed Trt, and feedback-controls the rotation speed Mr of the motor generator 8 .

As indicated by the solid line in the turbine rotation speed Tr from time t1 to time t2 in FIG. The supercharging pressure Pr hunts, and the followability of the turbine speed Tr is poor. Therefore, the control device 20 gives priority to the control of the rotation speed Mr of the motor generator 8 to the control of the opening W of the waste gate valve 10 . As indicated by the dashed line in FIG. 4, the turbine rotation speed Tr from time t1 to time t2, the turbine rotation speed Tr is maintained at the target turbine rotation speed Trt, and fluctuations in the turbine rotation speed Tr are suppressed. As a result, the control device 20 can efficiently operate the internal combustion engine 2, and the power performance of the vehicle is also improved.

Next, steps S4 to S8 will be described. Steps S4 to S8 are controls in the regeneration region in FIG.

In step S4, the control device 20 acquires the supercharging pressure Pr and determines whether or not the supercharging pressure Pr is equal to or higher than a predetermined value Prt. The predetermined value Prt may be set according to the value of the supercharging pressure Pr in the low-to-middle load range. On the other hand, in the present embodiment, the supercharging pressure Pr equal to or higher than the predetermined value Prt is the value of the supercharging pressure Pr when the internal combustion engine 2 is operating in the regeneration region shown in FIG. 3, for example. In this manner, supercharging is necessary for the operation of the internal combustion engine 2 in the medium-rotation/high-load to high-rotation/high-load range.

When the supercharging pressure Pr is equal to or higher than the predetermined value Prt (step S4 YES), the control device 20 determines whether or not the target supercharging pressure Pt is increasing (step S5). The target supercharging pressure Pt is rising, for example, as indicated by arrow B in FIG. This is a state in which the engine is reaccelerated near the maximum output of the internal combustion engine 2 from a state in which it has once decreased. When the target supercharging pressure Pt has increased (step S5 YES), the control device 20 controls the waste gate valve 10 to be closed with priority over the motor generator 8 (step S6). In such a vehicle state, the controller 20 causes the motor generator 8 to regenerate, as shown in FIG. The opening W of the valve 10 does not change. Therefore, when the wastegate valve 10 is controlled to close again, the wastegate valve 10 is quickly closed (for example, fully closed in this embodiment). Furthermore, since the opening degree W of the waste gate valve 10 is kept small, the amount of oxygen adsorbed by the catalyst device 18 due to the exhaust gas is small, and control for purging the adsorbed oxygen is suppressed. As a result, according to this control system 1 for the internal combustion engine 2, fuel consumption is also suppressed.

As indicated by the turbine rotation speed Tr from time t3 to time t5 in FIG. 4, the turbine 4 of the present embodiment rotates at a rotation speed of, for example, 150,000 to 200,000 rpm in the regeneration region. Therefore, power consumption is large when the motor generator 8 is powered in the regeneration region. Therefore, in the regeneration region, preferentially closing the wastegate valve 10 allows the supercharging pressure Pr to approach the target supercharging pressure Pt more quickly and reduces power consumption. In the present embodiment, the opening W of the wastegate valve 10 is fully closed as indicated by the opening W of the wastegate valve 10 from time t4 to time t5 in FIG. As a result, the control device 20 uses all the exhaust energy to raise the turbine speed Tr. As a result, the supercharging pressure Pr rises quickly, and the control device 20 can operate the internal combustion engine 2 efficiently.

If the target supercharging pressure Pt has not increased (step S5 NO), the control device 20 determines the target turbine speed Trt according to the target supercharging pressure Pt (step S7). The control device 20 may store the target turbine speed Trt in correspondence with the target supercharging pressure Pt in advance, or may calculate it using a coefficient or the like. After determining the target turbine rotation speed Trt, the control device 20 causes the motor generator 8 to regenerate, and feedback-controls the rotation speed Mr of the motor generator 8 so that the turbine rotation speed Tr becomes the target turbine rotation speed Trt (step S8). . In this manner, the control device 20 gives priority to regeneration of the motor generator 8 over the waste gate valve 10 in the regeneration region, and causes the boost pressure Pr to follow the target boost pressure Pt. As a result, the control device 20 can suppress fluctuations in the supercharging pressure Pr, thereby suppressing wasteful supercharging and fuel consumption that accompanies it. As a result, the control device 20 can operate the internal combustion engine 2 efficiently.

In step S7, the control device 20 uses the required output (torque) ETq, which is the target value of the output (torque) of the internal combustion engine 2, instead of the target turbine rotation speed Trt, to set the rotation speed Mr of the motor generator 8. may be controlled. For example, the control device 20 can feedback-control the rotation speed Mr of the motor generator 8 by pre-storing the target rotation speed Mrt of the motor generator 8 corresponding to the output target value or the torque target value. can.

After executing the process of step S6 or step S8, the control device 20 advances the process to step S1.

Next, steps S9 to S12 will be described. Steps S4 to S8 are controls in the power generation region of FIG.

When the supercharging pressure Pr is less than the predetermined value Prt (step S4 NO), the control device 20 determines whether or not there is a power generation request (step S9). Control device 20 may determine that there is a power generation request when the state of charge SOC of power storage device 12 is low. Alternatively, it may be determined that there is a power generation request based on a request from a vehicle-mounted device that uses electric power. In this embodiment, the value less than the predetermined value Prt is the value of the supercharging pressure Pr when the internal combustion engine 2 is operating in the power generation region, as indicated by arrow C in FIG. 3, for example.

When determining that there is a power generation request (step S9 YES), the control device 20 determines a target generated current value Bp (step S10). After determining the target generated current value Bp, the control device 20 determines a target generated torque Eet, which is the torque of the internal combustion engine 2 required for the motor generator 8 to generate the target generated current value Bp (step S11). The control device 20 adds the target power generation torque Eet to the required output ETq based on the accelerator opening Th to operate the internal combustion engine 2, and at the same time, feedback-controls the rotation speed Mr of the motor generator 8 to obtain the target power generation current value. The motor generator 8 is caused to generate power so as to reach Bp (step S12).

In this manner, the control device 20 preferentially controls the motor generator 8 when the supercharging pressure Pr is less than the predetermined value Prt and the motor generator 8 is caused to generate electric power by the rotation of the turbine 4 . This allows control device 20 to recover the exhaust energy and charge power storage device 12 . As a result, the control device 20 can operate the internal combustion engine 2 efficiently. Further, in this embodiment, the target value of the power generation amount is determined by the target power generation current value Bp of the motor generator 8 . Thereby, the control device 20 suppresses fluctuations in the target power generation torque Eet due to fluctuations in the power generation amount.

After executing the process of step S12, the control device 20 advances the process to step S1. Also, when there is no power generation request (step S9 NO), the control device 20 advances the process to step S1. The control device 20 repeatedly executes such processing at predetermined intervals.

As described above, according to the control system 1 of the internal combustion engine 2 of the present disclosure, one of the motor generator 8 and the waste gate valve 10 is preferentially controlled according to the state of the vehicle. As a result, the control system 1 of the internal combustion engine 2 generates power by the motor generator 8 while controlling the rotation speed Tr of the turbine according to the state of the vehicle. As a result, the control device 20 can operate the internal combustion engine 2 efficiently.

<Other embodiments>
Although the embodiments of the present disclosure have been described above, the present disclosure is not limited to the above embodiments, and various modifications can be made without departing from the scope of the invention. In particular, multiple modifications described herein can be arbitrarily combined as required.

(a) Although the control device 20 controls all the devices in the above embodiment, the present disclosure is not limited to this. A device for controlling motor generator 8 and a device for controlling other devices may be provided separately.

(b) In the above embodiment, the internal combustion engine 2 has been described as an example of a reciprocating gasoline internal combustion engine, but the present disclosure is not limited to this. The internal combustion engine 2 may be a rotary internal combustion engine or a diesel internal combustion engine. In the present embodiment, the internal combustion engine 2 has been described as an in-line internal combustion engine 2, but the internal combustion engine 2 may be an in-line internal combustion engine, a V-type internal combustion engine, or a horizontally opposed internal combustion engine. Further, the internal combustion engine 2 of the present embodiment has been described as an example of a direct injection type internal combustion engine, but the internal combustion engine 2 may be a direct injection type, a multi-port type in which an injector 2c is arranged in the intake passage of each cylinder, a direct injection type, or a direct injection type. The internal combustion engine 2 may be a combined injection type and multi-port type, or a semi-direct injection type internal combustion engine 2 .

1: Control system 2: Internal combustion engine 4: Turbine 6: Compressor 10: Waste gate valve 20: Control device Bp: Target generated current value Mr: Rotational speed Pr: Boost pressure Prt: Predetermined value Tr: Turbine rotational speed

Claims (6)

a turbine through which exhaust gas from an internal combustion engine mounted on a vehicle flows;
a compressor arranged coaxially with the turbine for supercharging the intake air of the internal combustion engine;
a rotating electrical machine that rotates the turbine and the compressor;
a wastegate valve that adjusts the amount of exhaust gas flowing to the turbine;
a control device that controls the rotating electric machine and the waste gate valve;
with
The control device preferentially controls either one of the rotating electric machine and the waste gate valve according to the state of the vehicle, and controls the rotation speed of the turbine while generating electric power with the rotating electric machine.
Control system for internal combustion engines. When boost pressure by the compressor is equal to or higher than a predetermined value and the rotation speed of the turbine is increased, the control device controls the wastegate valve with priority over the rotating electric machine.
A control system for an internal combustion engine according to claim 1. When boost pressure by the compressor is equal to or higher than a predetermined value and the rotation speed of the turbine is decreased, the control device controls the rotating electric machine with priority over the waste gate valve.
3. A control system for an internal combustion engine according to claim 1 or 2. The control device determines a target value of at least one of the output of the internal combustion engine, the torque of the internal combustion engine, and the rotation speed of the turbine when decreasing the rotation speed, and sets the desired value so that the target value is achieved. regenerating the rotating electric machine to
A control system for an internal combustion engine according to claim 3. The control device controls the rotating electrical machine with priority over the waste gate valve when the supercharging pressure by the compressor is less than a predetermined value and the rotating electrical machine is caused to generate power by the rotation of the turbine.
A control system for an internal combustion engine according to any one of claims 1 to 4. When causing the rotating electric machine to generate power, the control device calculates a target generated current value to be generated by the rotating electric machine, and controls the internal combustion engine based on the target generated current value.
A control system for an internal combustion engine according to claim 5.