Control device for a vehicle

Abstract

The present application improves the responsiveness of a fuel supplement process that increases engine speed when downshifting. A control device for a vehicle that has an engine connected to a manual transmission is configured to perform a delay process that delays operation of a throttle valve to an opening degree corresponding to a required load factor for a delay time, a fuel supplement process that increases the required load factor when the manual transmission is downshifted, and a delay prohibition process that prohibits the delay process from being performed when the fuel supplement process is performed.

Description

Technical Field

[0001] This invention relates to a vehicle control device. Background Technology

[0002] As a control device for a vehicle equipped with an engine connected to a transmission, the device described in Patent Document 1 is known. This vehicle control device performs a rev-matching process to increase the engine speed to the speed required for the shift when the transmission downshifts.

[0003] Patent Document 1: Japanese Patent Application Publication No. 2011-225050 Summary of the Invention

[0004] There is still room for improvement in shortening the time required for engine speed to rise through the aforementioned fuel replenishment process.

[0005] The vehicle control device for solving the above-mentioned problem is a vehicle control device having an engine connected to a transmission, wherein the vehicle control device is configured to perform the following processes: delay processing, delaying the operation of the throttle opening corresponding to the required load rate until the delay time has elapsed; rev-matching processing, increasing the required load rate when the transmission downshifts; and delay prohibition processing, prohibiting the delay processing from being performed during the rev-matching processing.

[0006] Invention Effects

[0007] The control device of the aforementioned vehicle has the effect of improving the responsiveness of the rev-matching process that increases engine speed during downshifting. Attached Figure Description

[0008] Figure 1 This is a diagram schematically illustrating the structure of a vehicle to which a control device is applied.

[0009] Figure 2 It is a schematic representation of what is applicable. Figure 1 A diagram showing the structure of the vehicle's control device.

[0010] Figure 3 yes Figure 2 Timing diagram of the engine control unit performing engine control without implementing delay processing. Figure 3 (A) indicates the shift in throttle opening. Figure 3 (B) indicates the shift in load factor. Figure 3 (C) indicates the shift of fuel injection.

[0011] Figure 4 yes Figure 2 The diagram shows the situation where the control device performs delayed processing to control the engine. Figure 4 (A) indicates the shift in throttle opening. Figure 4 (B) indicates the shift in load factor. Figure 4 (C) indicates the shift of fuel injection.

[0012] Figure 5 yes Figure 2 The flowchart shows the delay prohibition process executed by the control device. Detailed Implementation

[0013] The following is for reference. Figures 1-5 One embodiment of the vehicle control device will be described in detail.

[0014] <Structure of Vehicle Control Devices>

[0015] exist Figure 1 The diagram shows the drive system of a vehicle 10 to which the control device of this embodiment is applied. An engine 11 is mounted in the vehicle 10. The engine 11 is connected to the drive wheels 15 of the vehicle 10 via a manual transmission 13 and a differential 14. A clutch 12 is provided between the engine 11 and the manual transmission 13. The engine 11 has one or more combustion chambers 16 for combustion of the air-fuel mixture. For example, in Figure 1 In this configuration, the engine 11 has four combustion chambers 16. Furthermore, the engine 11 has an intake passage 17 that serves as a path for introducing air into each combustion chamber 16 and an exhaust passage 18 that serves as a path for discharging exhaust gas into each combustion chamber 16. A throttle valve 19 is provided in the intake passage 17. Additionally, the engine 11 has a separate fuel injector 20 and ignition device 21 for each combustion chamber 16.

[0016] exist Figure 2The structure of the electronic control unit 30 constituting the control device of this embodiment is shown. The electronic control unit 30 includes an arithmetic processing unit 31, a storage unit 32, an input circuit 33, and an output circuit 34. The storage unit 32 stores engine control programs and data. The electronic control unit 30 is configured such that the arithmetic processing unit 31 executes the program read from the storage unit 32, thereby performing various processes for engine control. Various sensors for detecting the operating status of the engine 11 or the operating status of the driver of the vehicle 10 are connected to the input circuit 33. Examples of sensors connected to the input circuit 33 include an air flow meter 35, a crankshaft angle sensor 36, a coolant temperature sensor 37, an accelerator pedal sensor 38, and a shift position sensor 39. The air flow meter 35 is a sensor that detects the flow rate of air flowing in the intake passage 17, i.e., the intake air volume GA. The crankshaft angle sensor 36 is a sensor that detects the crankshaft angle CNK, which is the rotation angle of the crankshaft, the output shaft of the engine 11. The coolant temperature sensor 37 is a sensor that detects the engine coolant temperature THW, which is the temperature of the coolant in the engine 11. Accelerator pedal sensor 38 is a sensor that detects the amount of accelerator pedal operation (ACC) performed by the driver of vehicle 10. Shift position sensor 39 is a sensor that detects the shift position (SFT) performed by the driver of vehicle 10 on the shift lever. Furthermore, drive circuits for various actuators of engine 11, such as throttle valve 19, fuel injector 20, and ignition device 21, are connected to the output circuit 34.

[0017] Furthermore, the electronic control unit 30 calculates the engine speed NE, which is the crankshaft rotational speed, based on the detection result of the crankshaft angle CNK. Also, the electronic control unit 30 calculates the engine load rate KL based on the engine speed NE, the throttle opening (which is the opening ratio of the throttle valve 19), and other parameters. The engine load rate KL represents the intake air charging efficiency η of the combustion chamber 16.

[0018] The electronic control unit 30, configured in this way, calculates the operating parameters of the actuators of the engine 11 based on the detection results of each sensor input to the input circuit 33. Examples of operating parameters calculated by the electronic control unit 30 include throttle opening (throttle valve opening rate of throttle valve 19), fuel injection quantity and timing of injector 20, and ignition timing of the air-fuel mixture based on ignition device 21. Then, the electronic control unit 30 outputs command signals corresponding to the calculated operating parameters to the drive circuits of each actuator via output circuit 34, thereby controlling the engine.

[0019] <Replenishing Treatment>

[0020] As part of engine control, the electronic control unit 30 performs rev-matching to increase engine speed NE during downshifting of the manual transmission 13. The electronic control unit 30 initiates rev-matching when it detects the shift position shift (SFT) and confirms the driver's downshift operation. During rev-matching, the electronic control unit 30 predicts the next gear in the manual transmission 13 based on the SFT detection. Then, the electronic control unit 30 calculates the target increase in engine speed NE required to shift to that gear. Finally, the electronic control unit 30 increases engine torque by widening the throttle opening, raising the engine speed NE to the target level.

[0021] <Delay processing>

[0022] When controlling the throttle valve 19, the electronic control unit 30 performs a delay process, which delays the operation of the throttle opening corresponding to the required load rate until the delay time has elapsed.

[0023] Figure 3 This illustrates an example of a control method where the throttle valve 19 is controlled without delay processing. Figure 3 (A) shows the required opening degree, the commanded opening value, and the shift in the actual opening degree of the throttle valve 19. Figure 3 (B) shows the shifts in required load factor, estimated load factor, and actual load factor. Figure 3 (C) shows the period of fuel injection.

[0024] The electronic control unit 30 calculates the required load rate, which is the required value of the engine load rate KL, based on the accelerator pedal operation amount ACC. Then, based on the required load rate, the electronic control unit 30 calculates the required opening degree of the throttle valve 19 to obtain an engine load rate KL equal to the required load rate, as the required opening degree value. Then, without delay processing, the electronic control unit 30 directly sets the required opening degree value as the opening command value for issuing a command to the drive circuit of the throttle valve 19. Figure 3 In this case, starting from time t0, the load rate is required to increase, and the opening command value also increases. Then, from time t0 onwards, the actual opening of the throttle valve 19, which has a delay relative to the opening command value, increases. Then, the actual engine load rate KL, which has a further delay relative to the actual opening, increases.

[0025] The electronic control unit 30 determines the fuel injection quantity based on the intake air charging efficiency η of the combustion chamber 16 during combustion, i.e., the engine load rate KL during combustion. Figure 3Time t2 represents the intake valve closing time IVC, and the subsequent time t3 represents the ignition time. After the intake valve closing time IVC, the intake charging efficiency η of the combustion chamber 16 does not change. Therefore, the engine load rate KL during combustion is determined at time t2, which is the intake valve closing time IVC. On the other hand, in Figure 3 In this case, fuel injection begins at a time t1, earlier than the closing time of the intake valve IVC. Therefore, the electronic control unit 30 determines the fuel injection quantity when the engine load rate KL during combustion is not determined.

[0026] In contrast, the electronic control unit 30 calculates an estimated load rate, which is a presumed value of the engine load rate KL during combustion, based on the rate of change of the actual throttle opening at the start of fuel injection. Then, the electronic control unit 30 determines the fuel injection quantity based on this calculated load rate. In this case, the change in throttle opening after time t1, which is the start time of fuel injection, cannot be reflected in the fuel injection quantity. Therefore, the engine load rate KL (estimated load rate) used to calculate the fuel injection quantity sometimes deviates from the actual engine load rate KL during combustion. For example, in… Figure 3 In this case, at time t1, which is the start of fuel injection, the actual opening rate of the valve changes rapidly. Therefore, at time t1, the electronic control unit 30 calculates a value greater than the actual load rate at time t2, which is the closing time of the intake valve (IVC), and uses this value as the estimated load rate. Therefore, at this time, the electronic control unit 30 issues a command to inject more fuel than originally required.

[0027] Furthermore, even if the rate of change of throttle opening, i.e., the operating speed of throttle valve 19, is the same, the change in engine load rate KL generated during the period from the start of fuel injection to the closing of the intake valve is greater at lower engine speeds NE than at higher engine speeds NE. Therefore, the deviation in fuel injection quantity when controlling throttle valve 19 without delay processing tends to be greater at lower engine speeds NE than at higher engine speeds NE.

[0028] Figure 4 This illustrates an example of a control method where throttle valve 19 is controlled by performing delayed processing. Figure 4 (A) shows the required opening degree, pre-read opening degree, opening command value, and actual opening degree shift of throttle valve 19. Figure 4 (B) shows the shifts in required load factor, estimated load factor, and actual load factor. Figure 4 (C) shows the period of fuel injection.

[0029] In this case, the electronic control unit 30 calculates a value that changes relative to the specified delay time required to delay the opening, and uses this value as the opening command value. Figure 4 In the case of [unclear context], the throttle opening is required to increase starting from time t10. Then, the throttle opening is required to increase again starting from time t11, after a delay time from time t10. Furthermore, the electronic control unit 30 calculates a predicted value for the throttle opening based on the required opening, assuming the required opening is set to the opening command value and the throttle valve 19 is operated. The predicted opening is the actual opening value after the predicted delay time. Moreover, the electronic control unit 30 similarly calculates the engine load rate KL as the estimated load rate value, assuming the actual opening changes. Then, the electronic control unit 30 calculates the fuel injection quantity based on the estimated load rate value at the start of fuel injection. Figure 4 In this case, the electronic control unit 30 calculates the fuel injection quantity based on the estimated load rate at time t12, which is the start time of fuel injection. In this case, the change in throttle opening during the period from the start of fuel injection to the elapsed delay time can be reflected in the fuel injection quantity. Therefore, by performing delay processing, the estimation error of the engine load rate KL (estimated load rate) used to calculate the fuel injection quantity can be reduced.

[0030] Furthermore, in this situation, even if the driver reduces the accelerator pedal input (ACC) after calculating the fuel injection quantity, this is reflected in the actual opening of the throttle valve 19 only after a delay. Moreover, it takes time for the change in throttle opening to be reflected in the engine load rate (KL). Therefore, in this situation, it is difficult to issue a command to inject more fuel than originally required. For example, in... Figure 4 In this case, the estimated load rate at time t11, which is the start time of fuel injection, is slightly smaller than the actual load rate at time t13, which is the engine load rate KL during combustion and the intake valve closing time IVC. Therefore, in this case, the electronic control unit 30 issues a command to inject fuel in a slightly smaller amount than originally required. In this case, by performing compensatory injection during the period from time t13, where the engine load rate KL during combustion is determined, to time t14, which is the ignition time, the insufficient fuel injection amount can be compensated.

[0031] <Delay Prohibition Handling>

[0032] As described above, by performing a delay processing when controlling the throttle valve 19, it is possible to suppress excess or insufficient fuel injection relative to the engine load rate KL. This, in turn, improves the control accuracy of the air-fuel ratio. On the other hand, in the aforementioned fuel replenishment process, it is required that the engine speed NE rise rapidly to the speed required for downshifting. However, even if a delay processing is implemented during the fuel replenishment process, it inevitably leads to a delay in the rise of the engine speed NE. In contrast, in this embodiment, the electronic control unit 30 performs a delay prohibition processing that prevents delay processing during fuel replenishment.

[0033] Figure 5 The flowchart shows the processing sequence of the electronic control unit 30 for delay prohibition processing. The electronic control unit 30 begins processing when the engine 11 has finished starting. Figure 5 The processing. Additionally, the "S" preceding the symbols in the diagram indicates "step".

[0034] exist Figure 5 In the process, the electronic control unit 30 waits for the start of the oil replenishment process (S100: Yes) and proceeds to step 102. In step 102, the electronic control unit 30 determines whether the engine coolant temperature THW exceeds the specified cold start determination value. The cold start determination value is set with the highest value of the range of engine coolant temperature THW when the engine 11 is in a cold start state. Therefore, an engine coolant temperature THW below the cold start determination value indicates that the engine 11 is operating in a cold start state. If it is determined that the engine coolant temperature THW is below the cold start determination value (No), the electronic control unit 30 returns the process to step 100. In this case, the electronic control unit 30 repeats the determination process of step 100 until the next oil replenishment process begins. In contrast, if it is determined that the engine coolant temperature THW exceeds the cold start determination value (Yes), the electronic control unit 30 proceeds to step 104.

[0035] In step 104, the electronic control unit 30 calculates a low-speed determination value based on the shift position SFT. The increase in engine speed NE required for the rev-matching process is calculated from the shift position SFT during downshifting. When the increase in engine speed NE is large, the electronic control unit 30 calculates a value larger than the value when the increase is small as the low-speed determination value.

[0036] Next, in step 106, the electronic control unit 30 determines whether the current engine speed NE exceeds the low speed determination value. Then, if it is determined that the current engine speed NE is below the low speed determination value (No), the electronic control unit 30 returns the process to step 100. On the other hand, if it is determined that the current engine speed NE exceeds the low speed determination value (Yes), the process proceeds to step 108.

[0037] In step 108, the electronic control unit 30 disables the delayed processing. Then, the electronic control unit 30 waits for the completion of the oil replenishment process (S110: Yes) and restarts the delayed processing. Then, after the delayed processing restarts, the electronic control unit 30 returns the processing to step 100.

[0038] <The Role of the Implementation Method>

[0039] The electronic control unit 30 disables delayed processing during rev-matching. If delayed processing is disabled, the increase in load rate required for rev-matching is immediately reflected in the throttle opening. Therefore, the decrease in the response speed of engine speed NE during rev-matching can be suppressed.

[0040] However, during fuel replenishment, the electronic control unit 30 does not prohibit delayed processing in the following two situations: When the engine coolant temperature THW is below the cold start determination value for the engine 11 (S102: Yes) and when the engine speed NE is below the low speed determination value (S106: Yes). Furthermore, the electronic control unit 30 can variably set the low speed determination value based on the shift position SFT (S104).

[0041] <Effects of the Implementation Method>

[0042] The control device for the vehicle 10 in this embodiment has the following effects.

[0043] (1) The electronic control unit 30 is configured as a control device for a vehicle 10 equipped with an engine 11 connected to a manual transmission 13. The electronic control unit 30 performs the following processes: a delay process, which delays the operation of the throttle opening corresponding to the required load rate until the delay time has elapsed; and a rev-matching process, which increases the required load rate when the manual transmission 13 downshifts. Furthermore, the electronic control unit 30 performs a delay prohibition process that prohibits the delay process during the rev-matching process. In such a control device for the vehicle 10, the responsiveness of the rev-matching process, which increases the engine speed NE during downshifting, is improved.

[0044] (2) When the engine speed NE is below the low speed determination value, the electronic control unit 30 prohibits the delay prohibition process. If the throttle valve 19 is controlled without delay processing at the low speed of the engine 11, the estimation accuracy of the engine load rate KL used to calculate the fuel injection quantity will deteriorate. Therefore, at low speed, even during fuel replenishment processing, the delay processing is implemented, thereby suppressing the deterioration of emissions caused by the deterioration of the air-fuel ratio control accuracy.

[0045] (3) The electronic control unit 30 variably sets the low speed determination value according to the shift position SFT. The increase in engine speed NE required for rev-matching varies according to the shift position SFT. Therefore, by performing the above variable setting, the deterioration of prohibited emissions accompanying delayed rev-matching can be suppressed within the range that allows for a decrease in the responsiveness of rev-matching.

[0046] (4) When the engine is cold, the exhaust purification device of the engine 11 is not fully activated, so the reduction in the control accuracy of the air-fuel ratio can easily lead to the deterioration of emissions. In contrast, the electronic control unit 30 prohibits delayed processing when the engine 11 is cold. In this way, when the engine is cold, by prioritizing the responsiveness of emissions rather than fuel replenishment processing, the responsiveness of fuel replenishment processing can be improved within an acceptable range for the deterioration of emissions.

[0047] (Other implementation methods)

[0048] This embodiment can be modified as follows. This embodiment and the following modifications can be combined with each other within the scope of technical inconsistency.

[0049] • You can also use parameters other than engine coolant temperature (THW) for testing. Figure 5 The determination of cold engine operation in step 102. The determination of cold engine operation can also be based on, for example, the external temperature or the engine coolant temperature (THW) at engine start and the cumulative intake air volume or elapsed time after engine start.

[0050] • Delayed processing during oil replenishment can also be prohibited even when the machine is running cold.

[0051] • Alternatively, the low-speed judgment value can be set to a fixed value that does not depend on the shift position SFT.

[0052] • Delayed processing during oil replenishment can also be prohibited at low speeds.

[0053] • In cases where delayed processing is prohibited, delayed processing can be restarted at a time other than the completion time of the refueling process.

[0054] The control device described in the above embodiments can also be adapted to... Figure 1 Vehicles with different drive system structures. For example, the control device described above can also be applied to vehicles equipped with automatic transmissions. In the case of vehicles equipped with automatic transmissions, downshifting can be performed even without increasing the engine speed NE, but sometimes a process of increasing the engine speed NE is performed as a rev-matching process. Even in vehicles where a rev-matching process is performed as a process, by providing the control device described above, the responsiveness of the rev-matching process can be improved.

[0055] (Additional Notes)

[0056] [Note 1] The vehicle control device according to any one of claims 1 to 3, wherein the delay prohibition process is prohibited when the engine is running cold.

[0057] Symbol Explanation

[0058] 10-Vehicle, 11-Engine, 12-Clutch, 13-Manual transmission, 14-Differential, 15-Wheel, 16-Combustion chamber, 17-Intake passage, 18-Exhaust passage, 19-Throttle valve, 20-Injector, 21-Ignition device, 30-Electronic control unit, 31-Processing unit, 32-Storage device, 33-Input circuit, 34-Output circuit, 35-Air flow meter, 36-Crankshaft angle sensor, 37-Water temperature sensor, 38-Accelerator pedal sensor, 39-Shift position sensor.

Claims

1. A control device for a vehicle, the vehicle having an engine connected to a transmission, the control device being characterized in that it performs the following processing: The delay processing will postpone the operation of the throttle opening corresponding to the required load rate until the delay time has elapsed; The oil replenishment process increases the required load rate when the transmission downshifts. and Delayed processing is prohibited, meaning that the delayed processing is prohibited during the oil replenishment process.

2. The vehicle control device according to claim 1, characterized in that, When the engine speed is below the low speed determination value, the delay prohibition process is disabled.

3. The vehicle control device according to claim 2, characterized in that, The low speed determination value can be variably set according to the shift position.

4. The vehicle control device according to claim 1, characterized in that, The delay suppression process is disabled when the engine is cold-running.

Images