JP2020118058A - Control device of internal combustion engine - Google Patents

Abstract

To further enhance drivability by properly suppressing a shock to a vehicle body, or a hiccup phenomenon.SOLUTION: On necessary condition that an accelerator pedal is pedaled in from a state that an accelerator opening is zero, or equal to or lower than a threshold near zero, a length of a time at which a state that the accelerator opening is zero, or exceeds the threshold, and an engine load rate is not in a low load is continued, and also on necessary condition that an increase amount of the engine load rate per unit time exceeds a prescribed value, a control device of an internal combustion engine performs first correction control for retardation-correcting ignition timing, and even if the length of the time at which the state that the accelerator opening is zero, or exceeds the threshold, and the engine load rate is not in the low load is continued exceeds the prescribed value without performing the first correction control, the control device performs second correction control for retardation-correcting the ignition timing on necessary condition that the engine load rate exceeds the prescribed value, and the increase of the unit time of the engine load rate is continued.SELECTED DRAWING: Figure 6

Description

The present invention relates to a control device that controls operation of an internal combustion engine mounted on a vehicle.

When the driver is not stepping on the accelerator pedal and intends to rapidly accelerate the vehicle by depressing the accelerator pedal strongly, the engine torque output from the internal combustion engine, which is the power source, suddenly increases and shocks the vehicle body, or There is a risk of causing hiccups (a phenomenon in which the vehicle body swings back and forth).

Therefore, conventionally, when the accelerator opening rapidly increases from 0 or less than a threshold value close to 0, correction control is performed to temporarily retard the ignition timing of the air-fuel mixture in the cylinders of the internal combustion engine, and the engine torque The rise is moderated to avoid a shock or a hiccup phenomenon on the vehicle body (see, for example, the following patent document).

JP, 2015-121189, A

In the existing system, the correction control for temporarily retarding the ignition timing is executed only when the driver strongly depresses the accelerator pedal from a state where the accelerator pedal is not depressed.

However, in reality, it is possible that the driver depresses the accelerator pedal lightly to start the vehicle and run to some extent, and thereafter, depresses the accelerator pedal strongly to accelerate the vehicle. In this case, since the correction control for retarding the ignition timing is not executed, a shock or hiccup may occur in the vehicle body.

The present invention was made in view of the above problems for the first time, and an object of the present invention is to appropriately suppress a shock or a hiccup phenomenon to a vehicle body to further enhance drivability.

In order to solve the above-mentioned problem, in the present invention, the accelerator pedal is depressed from a state in which the accelerator opening is 0 or a threshold value close to 0, the accelerator opening degree exceeds 0 or a threshold value close to 0, and the engine load factor is As long as the length of time for which a low load condition similar to idle operation is continued is within a predetermined value, and the increase amount of the engine load factor per unit time exceeds a predetermined value, the cylinder The first correction control for retarding the ignition timing of the air-fuel mixture filled in is performed, and the accelerator opening is greater than 0 or a threshold value close to 0 without performing the first correction control. Even if the length of time that the engine load factor continues to be in a low load state close to idle operation exceeds the predetermined value, the engine load factor exceeds the predetermined value and the engine load factor continues to increase. As a necessary condition, the control device of the internal combustion engine is configured to perform the second correction control for retarding the ignition timing of the air-fuel mixture charged in the cylinder.

With such a configuration, even if the driver depresses the accelerator pedal lightly to start the vehicle and travels to some extent and then strongly depresses the accelerator pedal, the second correction control suppresses a sharp increase in engine torque. It is possible to effectively suppress a shock or a hiccup phenomenon to the vehicle body.

More specifically, the first correction control is carried out on the condition that the engine load factor exceeds a first predetermined value, and the engine load factor exceeds a second predetermined value. It is preferable that the second correction control is performed under the above condition as a necessary condition, and the second predetermined value is set to a value higher than the first predetermined value. As a result, when the accelerator pedal is strongly depressed from the state where the accelerator opening is equal to or less than the threshold value close to 0, the first correction control can be promptly performed to suppress the occurrence of shock or hiccup of the vehicle body. When the accelerator pedal is strongly depressed from a state where the accelerator opening has already been opened to some extent, the second correction control can be performed at appropriate times to suppress the occurrence of shock or hiccup of the vehicle body.

According to the present invention, the drivability can be further enhanced by appropriately suppressing the shock or the hiccup phenomenon on the vehicle body.

The figure showing the schematic structure of the internal-combustion engine and the control device in one embodiment of the present invention. The flowchart which shows the example of a procedure of the process which the control apparatus of the same embodiment performs according to a program. The flowchart which shows the example of a procedure of the process which the control apparatus of the same embodiment performs according to a program. The flowchart which shows the example of a procedure of the process which the control apparatus of the same embodiment performs according to a program. FIG. 3 is a timing diagram illustrating the content of control performed by the control device of the same embodiment. FIG. 3 is a timing diagram illustrating the content of control performed by the control device of the same embodiment.

An embodiment of the present invention will be described with reference to the drawings. FIG. 1 shows an outline of a vehicle internal combustion engine in this embodiment. The internal combustion engine in the present embodiment is a spark ignition type four-stroke gasoline engine, and includes a plurality of cylinders 1 (one of which is shown in FIG. 1). An injector 11 for injecting fuel toward the intake port is provided upstream of the intake valve of each cylinder 1 and near the intake port connected to each cylinder 1. An ignition plug 12 is attached to the ceiling of the combustion chamber of each cylinder 1. The spark plug 12 receives an induction voltage generated by the ignition coil and causes a spark discharge between the center electrode and the ground electrode. The ignition coil is integrally built in the coil case together with an igniter which is a semiconductor switching element.

The intake passage 3 for supplying intake air takes in air from the outside and guides it to the intake port of each cylinder 1. An air cleaner 31, an electronic throttle valve 32, a surge tank 33, and an intake manifold 34 are arranged on the intake passage 3 in this order from the upstream side.

The exhaust passage 4 for discharging the exhaust guides the exhaust generated by burning the fuel in the cylinder 1 to the outside from the exhaust port of each cylinder 1. An exhaust manifold 42 and an exhaust purification three-way catalyst 41 are disposed on the exhaust passage 4.

The exhaust gas recirculation device 2 realizes a so-called high-pressure loop EGR, and an external EGR that connects the upstream side of the catalyst 41 in the exhaust passage 4 and the downstream side of the throttle valve 32 in the intake passage 3 to each other. A passage 21, an EGR cooler 22 provided on the EGR passage 21, and an EGR valve 23 that opens and closes the EGR passage 21 to control the flow rate of the EGR gas flowing through the EGR passage 21 are elements. The inlet of the EGR passage 21 is connected to the exhaust manifold 42 in the exhaust passage 4 or a predetermined position downstream thereof. The outlet of the EGR passage 21 is connected to a predetermined location in the intake passage 3 downstream of the throttle valve 32, specifically, to a surge tank 33.

An ECU (Electronic Control Unit) 0, which is a control device for an internal combustion engine of the present embodiment, is a microcomputer system having a processor, a memory, an input interface, an output interface, and the like. The ECU 0 may be composed of a plurality of ECUs or controllers communicatively connected to each other via an electric communication line such as CAN (Controller Area Network).

A vehicle speed signal a output from a vehicle speed sensor that detects the actual vehicle speed of the vehicle, a rotation angle of a crankshaft that is an output shaft of the internal combustion engine, and a crank angle sensor that detects an engine speed are output to an input interface of the ECU 0. The crank angle signal b, the amount of depression of the accelerator pedal, or the opening of the throttle valve 32 is detected as a sensor that detects the accelerator opening (so-called required engine load factor), the accelerator opening signal c, the intake passage 3 (particularly , An intake air temperature/intake pressure signal d output from a temperature/pressure sensor for detecting intake air temperature and intake pressure in the surge tank 33), a sensor for detecting the amount of depression of the brake pedal, or a brake hydraulic fluid discharged from a master cylinder. Brake pedal signal e output from the sensor that detects the master cylinder pressure, which is the pressure of the engine, cooling water temperature signal f output from the water temperature sensor that detects the cooling water temperature that indicates the temperature of the internal combustion engine, intake camshaft or exhaust cam A cam angle signal g output from the cam angle sensor at a plurality of cam angles of the shaft, a tilt angle output from a tilt angle sensor (or an acceleration sensor) that detects a slope of a road surface on which the vehicle is located (or, An acceleration signal h or the like is input.

From the output interface, the ignition signal i for the igniter of the spark plug 12, the fuel injection signal j for the injector 11, the opening operation signal k for the throttle valve 32, and the opening operation signal l for the EGR valve 23. Etc. are output.

The processor of the ECU 0 interprets and executes a program stored in advance in the memory, calculates operating parameters, and controls the operation of the internal combustion engine. The ECU 0 obtains various kinds of information a, b, c, d, e, f, g, h necessary for controlling the operation of the internal combustion engine via an input interface, and determines the amount of intake air (fresh air) taken into the cylinder 1. Operation parameters such as a required fuel injection amount, a fuel injection timing (including the number of fuel injections for one combustion), a fuel injection pressure, an ignition timing, a required EGR gas amount (or an EGR rate), and the like are determined. The ECU 0 applies various control signals i, j, k, l corresponding to the operating parameters via the output interface.

Further, the ECU 0 executes an idle stop for stopping the idle rotation of the internal combustion engine when a predetermined idle stop condition is satisfied. The ECU 0 determines that the brake pedal depression amount or the master cylinder pressure is equal to or higher than a predetermined value (the brake pedal is depressed), the cooling water temperature of the internal combustion engine is higher than a predetermined value, and the vehicle battery charge amount or the terminal voltage is equal to or higher than a predetermined value. High, the shift range is the driving range, the absolute value of the gradient of the road surface on which the vehicle is located is less than a predetermined value, the negative pressure stored by the brake booster is more than the predetermined value, and the previous idle Since the vehicle has been accelerated to a certain vehicle speed (for example, 10 km/h) or more from the end of the stop, and the current vehicle speed is less than or equal to a certain vehicle speed (for example, 9 km/h), the idle conditions are generally satisfied. Judge that the stop condition is met.

After the idle stop condition is satisfied, when the predetermined idle stop end condition is satisfied, the internal combustion engine is restarted. In the ECU 0, the brake pedal depression amount or the master cylinder pressure becomes 0 or less than the minimum value close to 0 (the brake pedal is no longer depressed), and conversely, the brake pedal depression amount or the master cylinder pressure further increases ( The brake pedal is pressed harder, the accelerator opening is increased (the accelerator pedal is pressed), the negative pressure stored in the brake booster drops below a predetermined value, and the idle stop state continues for a predetermined time. It is determined that the idle stop end condition is satisfied based on any one of (e.g., 3 minutes) has elapsed.

When starting the stopped internal combustion engine (including not only a return from idling stop but also a cold start), the ECU 0 inputs a control signal o to an electric motor (starter or ISG (Integrated Starter Generator), not shown). Then, cranking is performed in which fuel injection from the injector 11 and spark ignition by the spark plug 12 are performed while the crankshaft is rotationally driven by the electric motor. The cranking is considered to have completed the explosion when the internal combustion engine has gone from the initial explosion to the continuous explosion and the engine speed exceeds the complete explosion determination value and ends. The complete explosion determination value, which is the condition for ending cranking, can be increased or decreased according to the temperature of the internal combustion engine or the like. Specifically, the lower the cooling water temperature of the internal combustion engine, the higher the complete explosion determination value is set.

Therefore, the ECU 0 of the present embodiment causes a hiccup phenomenon in which the vehicle body is shocked when the driver of the vehicle depresses the accelerator pedal to accelerate the vehicle, or the vehicle body swings back and forth. In order to appropriately prevent the above, the ignition timing of the air-fuel mixture in the cylinder 1 of the internal combustion engine is set to the operating range of the internal combustion engine [engine speed, accelerator opening (or engine load factor, intake pressure in the surge tank 33). , Intake amount or fuel injection amount filled in the cylinder 1)] and the like, and correction control is performed to delay the base timing from the base timing, thereby gently increasing the rise of the engine torque.

Hereinafter, the correction control executed by the ECU 0 will be described in detail. 2 to 4 show a procedure example of processing executed by the ECU 0 of the present embodiment. FIG. 2 shows a process for two counter values I and II that the ECU 0 constantly keeps counting. In both the counter I and the counter II, the current accelerator opening is 0 or above a threshold value close to 0, and the current engine load factor is equal to the first predetermined value corresponding to idle operation or low load operation close to this. As long as the precondition that it exceeds is satisfied (step S1), the amount is increased by a predetermined amount per unit time (steps S2 and S4). As described above, the current accelerator opening is the depression amount of the accelerator pedal or the opening of the throttle valve 32. The current engine load factor can be estimated from the current engine speed, the intake pressure in the surge tank 33, the accelerator opening, and the like. The memory of the ECU 0 stores in advance map data or a functional expression that defines the relationship between the engine speed, the intake pressure, the accelerator opening, and the like and the engine load factor. The ECU 0 obtains the current engine load factor by searching the map with the current engine speed, intake pressure, accelerator opening, etc. as keys, or by substituting these into the functional expression for calculation.

If the above precondition is not satisfied, both the counter I and the counter II are reset to the minimum value (in particular, 0) (steps S5 and S6). In addition, the ECU 0 indicates that the current value of the counter II has increased to a predetermined value or more (in other words, the counter II has not been reset for a predetermined time (for example, 1.3 seconds. Specified that the current engine load factor exceeds the second predetermined value and the increase amount of the engine load factor per unit time exceeds the predetermined value for more than a predetermined time. When the condition is satisfied (step S3), only the counter II is reset to the minimum value (step S6). The second predetermined value in step S3 corresponds to an operation in which the load is already high to some extent and is higher than the first predetermined value in step S1.

Note that the ECU 0 executes the correction control for temporarily retarding the ignition timing and ends the correction control, and thereafter, when the precondition is not satisfied and is still satisfied (step S7), the counter I And the counter II are both set to the maximum value (step S8).

FIG. 3 is a process of determining whether or not the ECU 0 should execute the correction control for temporarily retarding the ignition timing. The ECU 0 determines that the current engine load factor exceeds a predetermined value (the same value as the first predetermined value or a value higher than the first predetermined value) (step S9), and the amount of increase in the accelerator opening per unit time exceeds a predetermined value ( In step S10), when the increase amount of the engine load factor per unit time exceeds a predetermined value (step S11) and the vehicle is about to accelerate suddenly, other required conditions (for example, the current engine speed is idle). The vehicle speed is higher than the rotational speed during operation, the current vehicle speed is higher than a predetermined value (5 km/h), the vehicle is running, the cooling water temperature of the internal combustion engine is higher than the predetermined value, and so on. S12), the current value of the counter I is less than or equal to the current value of the counter II (step S13), and the current value of the counter I is still less than or equal to the predetermined value (in other words, the counter I is not reset and continues to increase). When the length of time that it is present is a predetermined time (for example, 0.2 seconds) or less (step S14), correction control for temporarily retarding the ignition timing of the air-fuel mixture is performed (step S15).

The first correction control in step S15 is intended to mitigate a sharp rise in engine torque when the driver of the vehicle depresses the accelerator pedal abruptly and strongly. The execution of the correction control in step S15 is permitted because the condition that the current value of the counter I is equal to or less than the predetermined value is satisfied in step S14, that is, the accelerator opening degree that is 0 or less than a threshold value close to 0. Is exceeded and the engine load factor is above the first predetermined value only immediately thereafter.

Further, the ECU 0 determines that the current value of the counter II is lower than the current value of the counter I (step S13), and the current value of the counter II is still less than or equal to the predetermined value (in other words, the counter II is not reset and is increased). Even when the length of the continued time is a predetermined time (for example, 0.2 seconds) or less (step S16), the correction control for temporarily retarding the ignition timing of the air-fuel mixture is performed (step S16). S17).

The second correction control of step S17 is to control the engine torque when the driver of the vehicle depresses the accelerator pedal lightly to start the vehicle from a state in which the accelerator pedal is not depressed and the accelerator pedal is strongly depressed after traveling for a while. The purpose is to suppress a sudden increase. The specific condition that the current value of the counter II has increased above a predetermined value, the current engine load factor exceeds the second predetermined value, and the increase amount of the engine load factor per unit time exceeds the predetermined value is satisfied. Then, the counter II is once reset to the minimum value, and as a result, the current value of the counter II falls below the current value of the counter I. If the condition that the current value of the counter II is less than or equal to the predetermined value is satisfied in step S16 even if the condition of step S14 that the current value of the counter I is less than or equal to the predetermined value is not satisfied in step S16, Execution of correction control is permitted.

FIG. 4 is a process in which the ECU 0 determines whether to end the correction control for temporarily retarding the ignition timing. The ECU 0 starts executing the correction control in step S15 or S17, and a predetermined time has passed (step S18). When the increase amount of the engine speed per unit time is less than or equal to a predetermined value (step S19), the engine load factor When at least one of the deceleration state in which the amount of decrease per unit time is equal to or greater than the predetermined value (step S20) is satisfied, the correction control ends (step S21).

FIG. 5 and FIG. 6 show patterns of correction control executed by the ECU 0 of this embodiment. In the figure, “idle” is ON during idle operation in which the accelerator opening is 0 or less than a threshold value close to 0, and is OFF in non-idle operation in which the accelerator opening degree is 0 or exceeds a threshold value close to 0. The "load" is turned on when the engine load factor exceeds the first predetermined value, and is turned off when the engine load factor is equal to or less than the first predetermined value. “Idle” and “load” correspond to the preconditions referred to in step S1. The “high load during acceleration” is ON when the engine load factor exceeds the second predetermined value and the increase amount of the engine load factor per unit time exceeds the predetermined value, and is OFF when it is not. “High load during acceleration” corresponds to the specific condition referred to in step S3. A time point t ₀ is a time point when the engine speed and the vehicle speed start remarkable acceleration, a time point t ₁ is a time point when the correction control for retarding the ignition timing is started, a time point t ₂ is a time point when the correction control is ended, and a time point t ₃ Is the point in time when the engine speed and the vehicle speed decrease.

FIG. 5 shows a case where the driver suddenly and strongly depresses the accelerator pedal from a state in which the accelerator pedal is not depressed, and is a case where the first correction control of step S15 is performed. On the other hand, FIG. 6 shows a case where the driver depresses the accelerator pedal lightly to start the vehicle from a state in which the accelerator pedal is not depressed, and the accelerator pedal is strongly depressed after traveling to some extent. This is a case where correction control is performed. In the latter case, execution of the correction control is started at the time point t ₁ when the specific condition is satisfied and the counter II is reset to the minimum value. The time point t ₁ is later than the time point when the precondition that the accelerator opening is not 0 and the engine load factor is larger than that during idling is satisfied.

After the time t ₃ when the condition for ending the correction control is satisfied, the retarded ignition timing is gradually advanced toward the base timing corresponding to the operating region of the internal combustion engine.

In the present embodiment, the accelerator pedal is depressed from a state in which the accelerator opening is 0 or a threshold value close to 0, the accelerator opening is 0 or a threshold value close to 0, and the engine load factor is not low load close to idle operation. The air-fuel mixture filled in the cylinder 1 is required on condition that the length of time for which the state is continued is within a predetermined value, and that the increase amount of the engine load factor per unit time exceeds a predetermined value. A first correction control for retarding the ignition timing of the engine is executed, and the accelerator opening exceeds a threshold value of 0 or a value close to 0 without executing the first correction control and the engine load factor is in an idle operation. Even if the length of time that the engine is not in a low load state exceeds the prescribed value, the engine load factor exceeds the prescribed value, and the increase amount of the engine load factor per unit time exceeds the prescribed value. The control device 0 of the internal combustion engine is configured to execute the second correction control for retarding the ignition timing of the air-fuel mixture charged in the cylinder 1 on the condition that the operation is continued.

According to this embodiment, even when the driver depresses the accelerator pedal lightly to start the vehicle and travels to some extent and then strongly depresses the accelerator pedal, it is possible to carry out the second correction control in a timely manner. With this second correction control, it is possible to suppress a sudden increase in engine torque and effectively suppress a shock or a hiccup phenomenon to the vehicle body.

The counter II that triggers the execution of the second correction control is set to the minimum value unless the specific condition that the current value of the counter II has increased above a predetermined value and the engine load factor continues to increase. Not reset. While the driver repeatedly presses or does not step on the accelerator pedal, the specific condition is not satisfied, the counter II is not reset, and the second correction control is not executed. Therefore, it is possible to avoid unnecessarily continuing the ignition timing retard correction while the vehicle is traveling. Also, when the driver of the running vehicle is depressing the accelerator pedal to overtake the preceding vehicle, it is already in the medium to high load operating range and the engine load factor saturates and does not continue to increase. After all, the second correction control is not executed. In general, the response to the driver's acceleration request can be secured.

In addition, in the present embodiment, the first correction control is performed on the condition that the engine load factor exceeds the first predetermined value, and the engine load factor exceeds the second predetermined value. The second correction control is performed under the above condition as a necessary condition, and the second predetermined value is set to a value higher than the first predetermined value. As a result, when the accelerator pedal is strongly depressed from the state where the accelerator opening is equal to or less than the threshold value close to 0, the first correction control can be promptly performed to suppress the occurrence of shock or hiccup of the vehicle body. When the accelerator pedal is strongly depressed from a state in which the accelerator opening has already been opened to some extent, the second correction control can be executed to suppress the occurrence of shock or hiccup of the vehicle body.

The present invention is not limited to the embodiments described in detail above. The specific configuration of each unit, the procedure of processing, and the like can be variously modified without departing from the spirit of the present invention.

The present invention can be applied to control of an internal combustion engine mounted on a vehicle.

0... Control unit (ECU)
1... Cylinder 12... Ignition plug 3... Intake passage 32... Throttle valve a... Vehicle speed signal b... Crank angle signal c... Accelerator opening signal i... Ignition signal

Claims (2)

The accelerator pedal is stepped on from a state in which the accelerator opening is 0 or less than a threshold value close to 0, and the accelerator opening exceeds 0 or a threshold value close to 0 and the engine load factor continues to be in a low load state close to idle operation. The ignition timing for the air-fuel mixture filled in the cylinders is delayed on the condition that the length of time that the engine is operating is within a predetermined value and that the amount of increase in the engine load factor per unit time exceeds a predetermined value. Perform the first correction control to correct the angle,
In addition, the length of time during which the accelerator opening degree is 0 or a threshold value close to 0 and the engine load factor is not in a low load close to idle operation without performing the first correction control is a predetermined value. If the engine load factor exceeds the predetermined value and the engine load factor continues to increase, the ignition timing of the air-fuel mixture charged in the cylinder is retarded. A control device for an internal combustion engine that performs the correction control of the above. The first correction control is carried out on the condition that the engine load factor exceeds a first predetermined value, and the first correction control is executed on the condition that the engine load factor exceeds a second predetermined value. To perform the second correction control,
The control device for an internal combustion engine according to claim 1, wherein the second predetermined value is a value higher than the first predetermined value.

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