Vehicle control device

Abstract

To provide a control device of a vehicle for suppressing the occurrence of knocking during execution of upshift processing in a supercharging operation state.SOLUTION: A control device for a vehicle including an engine having a supercharger and an automatic transmission, the control device comprising: a torque control unit configured to execute torque-down processing for reducing an opening degree of a throttle valve of the engine while maintaining the supercharging operation state during execution of upshift processing of the automatic transmission in a supercharging operation state of the engine; and a determination unit configured to determine whether knocking is likely to occur due to execution of the torque-down processing based on at least one of a property of fuel, an intake air temperature, a temperature of the engine, and a knock learning value before the torque-down processing is executed. An ignition control section configured to retard an ignition timing of the engine during execution of the torque down process in a case where the determination section makes an affirmative determination as compared to a case where the determination section makes a negative determination.SELECTED DRAWING: Figure 2

Description

[Technical Field]

[0001] The present invention relates to a vehicle control device. [Background technology]

[0002] When an automatic transmission is performing an upshift process while the engine is in a supercharged operating state, a torque reduction process may be performed to reduce the opening of the engine throttle valve while maintaining the supercharged operating state (see, for example, Patent Document 1). [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Laid-Open No. 2013-238195 Summary of the Invention [Problem to be solved by the invention]

[0004] When the throttle valve opening decreases during supercharging, the engine back pressure increases, which can increase the internal EGR amount and raise the in-cylinder temperature, potentially causing knocking.

[0005] SUMMARY OF THE INVENTION It is therefore an object of the present invention to provide a vehicle control device that suppresses the occurrence of knocking during an upshift process in a supercharged operating state. [Means for solving the problem]

[0006] The above object can be achieved by a control device for a vehicle equipped with an engine having a supercharger and an automatic transmission, the control device comprising: a torque control unit that, when the engine is in a supercharged operating state and an upshift process of the automatic transmission is being performed, executes a torque down process that reduces the opening of a throttle valve of the engine while maintaining the supercharged operating state; a determination unit that, before the torque down process is performed, determines whether or not there is a possibility of knocking due to the execution of the torque down process based on at least one of fuel properties, intake air temperature, the temperature of the engine, and a knock learning value; and an ignition control unit that, when a positive determination is made by the determination unit, retards the ignition timing of the engine during the execution of the torque down process more than when a negative determination is made by the determination unit.

[0007] When the determination unit makes a positive determination, the ignition control unit may maintain the ignition timing constant during the execution of the torque reduction process.

[0008] The torque control unit may execute a torque recovery process after completion of the torque down process, while maintaining the supercharging operation state, to increase the opening of the throttle valve more than during execution of the torque down process, and when a positive determination is made by the determination unit, the ignition control unit may retard the ignition timing during execution of the torque recovery process more than when a negative determination is made by the determination unit, and may maintain the ignition timing constant during execution of the torque recovery process, and then gradually advance the ignition timing toward the ignition timing that would be controlled in the case of a negative determination by the determination unit.

[0009] When a positive determination is made by the determination unit, the ignition control unit may maintain the ignition timing during execution of the torque recovery process constant and more retarded than the ignition timing during execution of the torque down process, and then advance the ignition timing.

[0010] The determination unit may make a positive determination when the intake air temperature is equal to or higher than a predetermined value, the engine temperature is equal to or higher than a predetermined value, and the knock learning value is equal to or lower than a predetermined value. [Effects of the Invention]

[0011] According to the present invention, it is possible to provide a vehicle control device that suppresses the occurrence of knocking during an upshift process in a supercharged operating state. [Brief explanation of the drawings]

[0012] [Figure 1] FIG. 1 is a schematic configuration diagram of a vehicle. [Figure 2] 4 is a flowchart illustrating an example of upshift control in a supercharged operating state. [Figure 3] 4 is a timing chart illustrating an example of upshift control in a supercharged operating state. DETAILED DESCRIPTION OF THE INVENTION

[0013] [Vehicle outline] FIG. 1 is a schematic diagram of a vehicle 100. The vehicle 100 includes an engine 1, an intake passage 3, an exhaust passage 4, a turbocharger 5, an intercooler 6, a catalyst 7a, a filter 7b, a bypass passage 8, a wastegate valve (hereinafter referred to as WGV) 9, an automatic transmission 21, a differential gear 23, wheels 25, and an ECU (Electronic Control Unit) 30. The engine 1 is a gasoline engine. The driving force of the engine 1 is transmitted to the wheels 25 via the automatic transmission 21 and the differential gear 23. The vehicle 100 is an engine vehicle equipped with the engine 1 as a driving source. However, the vehicle 100 may be a hybrid vehicle equipped with a motor in addition to the engine 1 as a driving source.

[0014] The engine 1 has four cylinders 2, but the number of cylinders is not limited to this. Each cylinder 2 is provided with a fuel injection valve 2a and a spark plug 2b. An intake passage 3 and an exhaust passage 4 are connected to the engine 1. A compressor 5b of a supercharger 5 is disposed in the intake passage 3. A turbine 5a of the supercharger 5 is disposed in the exhaust passage 4. The turbine 5a and compressor 5b are coaxially connected by a shaft. The supercharger 5 supercharges the intake air to the engine 1.

[0015] A bypass passage 8 that bypasses the turbine 5a and a WGV 9 that opens and closes the bypass passage 8 are provided in the exhaust passage 4. The opening of the WGV 9 is adjusted by an electric actuator 9a that drives the WGV 9. The opening of the WGV 9 is feedback-controlled by the ECU 30 so that the boost pressure becomes a target boost pressure that is determined according to the operating state of the engine 1. The ECU 30 outputs a command value to the electric actuator 9a to control the opening of the WGV 9. The WGV 9 is a normally closed type that is fully closed when the electric actuator 9a is not energized.

[0016] An intercooler 6 that cools the intake air is arranged downstream of the compressor 5b in the intake passage 3. A throttle valve 3a that adjusts the amount of intake air of the engine 1 is arranged downstream of the intercooler 6 in the intake passage 3.

[0017] A catalyst 7a for purifying exhaust gas and a filter 7b for collecting exhaust particulates are provided downstream of the turbine 5a in the exhaust passage 4. The filter 7b is provided downstream of the catalyst 7a. The catalyst 7a contains catalytic metals such as platinum (Pt), palladium (Pd), and rhodium (Rh), has oxygen storage capacity, and purifies NOx, HC, and CO. The filter 7b is a porous ceramic structure.

[0018] The ECU 30 includes a CPU (Central Processing Unit), a ROM (Read Only Memory), and a RAM (Random Access Memory). The ECU 30 controls the engine 1 based on information from sensors and information previously stored in the ROM in accordance with a control program previously stored in the ROM. The ECU 30 is an example of a vehicle control device.

[0019] The ECU 30 controls the operating state of the engine 1 based on detection signals from various sensors, such as a crank angle sensor 11, an air flow meter 12, an air-fuel ratio sensor 13, an accelerator opening sensor 14, a knock sensor 15, a water temperature sensor 16, a fuel property sensor 17, and an intake air temperature sensor 18. The crank angle sensor 11 detects the rotation angle of the crankshaft of the engine 1. The air flow meter 12 detects the amount of intake air taken into the intake passage 3. The air-fuel ratio sensor 13 detects the air-fuel ratio of the exhaust gas discharged from the engine 1. The accelerator opening sensor 14 detects the accelerator opening, which is the amount of operation of the accelerator pedal. The knock sensor 15 detects knocking of the engine 1. The water temperature sensor 16 detects the temperature of the coolant for the engine 1. The fuel property sensor 17 detects the property of the fuel, specifically the octane number. The intake air temperature sensor 18 detects the temperature of the intake air taken into the intake passage 3.

[0020] The ECU 30 grasps the rotation speed and load of the engine 1 based on output signals from various sensors. The ECU 30 outputs command signals to various drive circuits connected to output ports according to the operating state grasped in this way. The controls performed by the ECU 30 in this way include throttle control for adjusting the opening of the throttle valve 3a, fuel injection control for adjusting the injection amount of the fuel injection valve 2a, and ignition timing control for adjusting the ignition timing of the spark plug 2b.

[0021] [Upshift control during supercharged operation] 2 is a flowchart illustrating upshift control in a supercharged operating state. The ECU 30 determines whether or not there is a request to upshift the automatic transmission 21 while the engine 1 is in a supercharged operating state (step S1). For example, if the opening instruction value for the WGV 9 is a value other than fully open, the engine 1 is considered to be in a supercharged operating state. An upshift request is a request to change the gear ratio of the automatic transmission 21 to a relatively smaller gear ratio (higher gear ratio). If the answer is No in step S1, this control ends.

[0022] If the answer is Yes in step S1, the ECU 30 determines whether or not knocking is likely to occur in the engine 1 due to a torque down process executed together with an upshift process, which will be described later (step S2). Whether or not knocking is likely to occur is determined based on the fuel properties, the intake air temperature, the temperature of the engine 1, and the knock learning value. Specifically, it is determined that knocking is likely to occur when (1) the octane number of the fuel is less than a predetermined value, (2) the intake air temperature is equal to or higher than a predetermined temperature, (3) the temperature of the engine 1 is equal to or higher than a predetermined temperature, and (4) the knock learning value is equal to or lower than a predetermined value. In this embodiment, if all of the above conditions (1) to (4) are satisfied, the answer is Yes in step S2. If any one of the above conditions (1) to (4) is not satisfied, the answer is No in step S2.

[0023] Regarding the above condition (1), the predetermined value is, for example, less than 96, i.e., when the fuel is regular, not premium, gasoline. The octane number of the fuel may be obtained by the ECU 30 based on the detection value of the fuel property sensor 17, or may be estimated by other known methods.

[0024] Regarding condition (2), the higher the intake air temperature, the higher the in-cylinder temperature, making knocking more likely to occur. The intake air temperature is acquired by ECU 30 based on the intake air temperature sensor 18. Regarding condition (3), the temperature of the engine 1 is the temperature of the coolant, but the temperature of the lubricating oil that lubricates the engine 1 may also be used. The higher these temperatures are, the higher the in-cylinder temperature of the engine 1 becomes, making knocking more likely to occur. The coolant temperature is acquired by ECU 30 based on the detection value of water temperature sensor 16.

[0025] Regarding condition (4), the knock learning value is the amount by which the ignition timing is advanced by knock control. The smaller the knock learning value, the more likely knocking occurs, i.e., the more the ignition timing is set to the retarded side. Knock control is a control that updates the value of the knock control amount, which is the advance correction amount of the ignition timing for knock control, as the knock learning value depending on whether knocking is detected by knock sensor 15.

[0026] If the answer is No in step S2, the ECU 30 executes an upshift process (step S3). During the upshift process, the engine 1 is maintained in a supercharged operating state. That is, the opening of the WGV 9 when the answer is Yes in step S1 is maintained. This ensures acceleration performance after the upshift process is completed. Next, during the upshift process, the ECU 30 executes a torque reduction process by reducing the opening of the throttle valve 3a (step S4). Because the torque reduction process reduces the torque of the engine 1, the occurrence of shock in the inertia phase during the upshift process is suppressed. Furthermore, during the upshift process and after the torque reduction process is completed, the ECU 30 executes a torque recovery process by returning the opening of the throttle valve 3a to the original opening (step S5). This ensures the torque of the vehicle 100 after the upshift process is completed.

[0027] If the answer is Yes in step S2, the ECU 30 executes an upshift process (step S6). Even in this case, the engine 1 is maintained in a supercharged operating state while the upshift process is being executed. Next, while the upshift process is being executed, the ECU 30 executes a torque reduction process and an ignition retard process similar to those in step S4 (step S7). As described above, the torque reduction process suppresses the occurrence of shock during the inertia phase. The ignition retard process is a process for retarding the ignition timing from the ignition timing in step S4. This suppresses the occurrence of knocking while the upshift process is being executed.

[0028] After the torque reduction process is completed, the ECU 30 executes the torque restoration process and the ignition timing retard process similar to those of step S5 (step S8). The ignition timing retard process here retards the ignition timing from the ignition timing in step S5. This suppresses the occurrence of knocking during the upshift process after the torque reduction process is completed.

[0029] Fig. 3 is a timing chart illustrating upshift control in a supercharged operating state. Fig. 3 shows the execution state of the upshift process, the torque of the engine 1, and the transition of the ignition timing. Regarding the ignition timing, the dotted line indicates the normal ignition timing when the determination in step S2 is No, and the solid line indicates the retarded ignition timing when the determination in step S2 is Yes. The case where the ignition retard process is executed will be described below.

[0030] When the upshift process starts (t1), the throttle valve 3a is opened less, the torque reduction process is executed (t2), and the ignition timing retard process is executed (t3). The retarded ignition timing is maintained constant during the torque reduction process, which stabilizes the combustion state.

[0031] When the torque reduction process is completed, a torque restoration process is executed (t4) to increase the throttle valve 3a opening back to its original opening, and an ignition retard process is executed (t5). The retarded ignition timing during the torque restoration process is maintained more retarded than the retarded ignition timing during the torque reduction process. This prevents knocking caused by a sudden increase in intake air volume due to the increased throttle valve 3a opening caused by the torque restoration process. Furthermore, in this case, the retarded ignition timing is maintained constant for a predetermined period, stabilizing the combustion state.

[0032] The retarded ignition timing is then gradually returned to the advance side (t6), and the upshift process ends when the retarded ignition timing becomes the normal ignition timing (t7). By gradually returning the retarded ignition timing to the advance side in this way, the combustion state is stabilized while the torque of the engine 1 is increased, and acceleration performance after the upshift process is ensured.

[0033] In step S2, it is determined that knocking may occur when all of conditions (1) to (4) are satisfied, but this is not limiting. For example, it may be determined that knocking may occur when any one of conditions (1) to (4) is satisfied. Also, for example, the retard amount in steps S4 and S5 may be increased as more of conditions (1) to (4) are satisfied. This is because the more of conditions (1) to (4) are satisfied, the more likely knocking is to occur as a result of the execution of the torque reduction process.

[0034] In step S2, the possibility of knocking may be determined by setting priorities for the conditions. For example, the priorities may be set in the order of decreasing priority: condition (1), condition (4), condition (3), and condition (2). In this case, for example, if condition (1) is satisfied, step S2 may be determined as "Yes" regardless of whether the other conditions are satisfied. Alternatively, if condition (1) is not satisfied but all of the other conditions are satisfied, it may be determined that there is a possibility of knocking occurring.

[0035] In addition, in a vehicle that is not provided with the above-described fuel property sensor 17, the possibility of knocking may be determined in step S2 based on conditions (2) to (4).

[0036] The ignition timing retard processes in steps S7 and S8 are processes for retarding the ignition timing compared with the ignition timing in steps S4 and S5, respectively, and are therefore not intended to set the ignition timing in steps S4 and S5 to the MBT (Minimum Advance for the Best Torque) ignition timing.

[0037] Although the embodiments of the present invention have been described in detail above, the present invention is not limited to such specific embodiments, and various modifications and variations are possible within the scope of the gist of the present invention as defined in the claims. [Explanation of symbols]

[0038] 1 engine 2b spark plug 3a Throttle valve 5. Turbocharger 5a Turbine 8 Bypass Passage 9 Wastegate valve 14 Accelerator opening sensor 30 ECU (control unit, torque control unit, judgment unit, ignition control unit) 100 vehicles

Claims

1. A control device for a vehicle equipped with an engine having a supercharger and an automatic transmission, a torque control unit that, while the engine is in a supercharged operating state and an upshift process of the automatic transmission is being performed, executes a torque down process to reduce an opening degree of a throttle valve of the engine while maintaining the supercharged operating state; a determination unit that determines, before the torque reduction process is executed, whether or not there is a possibility that knocking will occur due to the execution of the torque reduction process, based on at least one of a fuel property, an intake air temperature, a temperature of the engine, and a knock learning value; an ignition control unit that, when a positive determination is made by the determination unit, retards the ignition timing of the engine during execution of the torque down processing more than when a negative determination is made by the determination unit.

2. 2. The vehicle control device according to claim 1, wherein the ignition control unit maintains the ignition timing constant during the execution of the torque reduction process when the determination unit makes a positive determination.

3. the torque control unit executes a torque recovery process after the torque down process has ended, in which the opening degree of the throttle valve is increased compared to when the torque down process was being executed while maintaining the supercharging operation state, 3. The vehicle control device of claim 2, wherein when a positive determination is made by the determination unit, the ignition control unit retards the ignition timing during execution of the torque recovery process compared to when a negative determination is made by the determination unit, and after maintaining the ignition timing constant during execution of the torque recovery process, gradually advances the ignition timing toward the ignition timing that is controlled when a negative determination is made by the determination unit.

4. 4. The vehicle control device according to claim 3, wherein, when a positive determination is made by the determination unit, the ignition control unit maintains the ignition timing during execution of the torque recovery process constant and more retarded than the ignition timing during execution of the torque down process, and then advances the ignition timing.

5. 5. The vehicle control device according to claim 4, wherein the determination unit makes a positive determination when the intake air temperature is equal to or higher than a predetermined value, the engine temperature is equal to or higher than a predetermined value, and the knock learning value is equal to or lower than a predetermined value.

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