Vehicle control device

Abstract

To suppress deterioration in warming-up performance of a catalyst during selection of a non-running range.SOLUTION: A vehicle comprises an internal combustion engine having a crank shaft, a motor generator, an automatic transmission and a catalyst. The automatic transmission can be switched between a running range and a non-running range. The catalyst is used for purifying exhaust air. The vehicle further comprises a water temperature sensor, an airflow meter and a control device. The control device can execute a catalyst warming-up process for prompting warming-up of the catalyst. The catalyst warming-up process is a process for increasing loads of the internal combustion engine by increasing a specific amount, with respect to electric power generated by the motor generator at the time when the catalyst warming-up process is not executed. The specific amount is calculated based on an amount of air and a temperature of cooling water. The specific amount calculated when the automatic transmission is in the non-running range is larger in comparison with the specific amount calculated when the transmission is in the running range.SELECTED DRAWING: Figure 3

Description

Technical Field

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

Background Art

[0002] The vehicle described in Patent Document 1 includes an internal combustion engine and a motor generator. The motor generator can apply positive torque to the output shaft of the internal combustion engine. Further, the motor generator also functions as a generator. When the motor generator functions as a generator, the motor generator applies negative torque to the output shaft of the internal combustion engine.

[0003] The vehicle described in Patent Document 1 includes an automatic transmission, a catalyst, and a control device. The catalyst is located in the middle of the exhaust passage of the internal combustion engine. The transmission is connected to the output shaft of the internal combustion engine. The control device controls the internal combustion engine and the motor generator. The control device can execute a catalyst warm-up process for promoting the warm-up of the catalyst. In the catalyst warm-up process, the control device increases the load of the internal combustion engine by increasing the power generation amount of the motor generator to promote the warm-up of the catalyst.

Prior Art Documents

Patent Documents

[0004]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0005] In the vehicle described in Patent Document 1, the transmission can switch between a driving range capable of transmitting torque to the drive wheels of the vehicle and a non-driving range that does not transmit torque to the drive wheels. In the non-driving range, the load on the internal combustion engine is smaller than in the driving range. Therefore, in the catalyst warm-up process, if the power generation amount of the motor generator is set to be constant regardless of whether it is in the driving range or the non-driving range, there is a risk that the catalyst may not be sufficiently warmed up in the non-driving range.

Means for Solving the Problems

[0006] To solve the above problems, the present invention provides a control device applied to a vehicle including an internal combustion engine having a crankshaft, a motor generator capable of applying torque to the crankshaft, a transmission connected to the crankshaft and capable of switching between a driving range capable of transmitting torque to the drive wheels and a non-driving range that does not transmit torque to the drive wheels, a catalyst located in the middle of the exhaust passage of the internal combustion engine for purifying exhaust gas, a water temperature sensor for detecting the cooling water temperature of the internal combustion engine, and an air flow meter located in the middle of the intake passage of the internal combustion engine for detecting the amount of air flowing into the internal combustion engine. The control device is capable of executing a catalyst warm-up process for promoting the warm-up of the catalyst. The catalyst warm-up process is a process of increasing the load of the internal combustion engine by increasing a specified amount calculated based on the amount of air and the cooling water temperature with respect to the power generation amount of the motor generator when the catalyst warm-up process is not being executed. The specified amount calculated in the non-driving range is larger than the specified amount calculated in the driving range.

[0007] According to the above configuration, the power generation amount of the motor generator can be set larger during non-driving range selection than during driving range selection. Thereby, the difference between the load on the internal combustion engine during non-driving range selection and the load on the internal combustion engine during driving range selection can be reduced. That is, according to the above configuration, even during non-driving range selection, sufficient catalyst warm-up performance similar to that during driving range selection can be obtained.

Brief Description of the Drawings

[0008]

Figure 1

Figure 2

Figure 3

Embodiments for Carrying Out the Invention

[0009] Hereinafter, an embodiment of a control device for a vehicle will be described with reference to the drawings. <Configuration of the Vehicle's Drive System> As shown in FIG. 1, the vehicle 500 includes an internal combustion engine 10, a transmission unit 20, left and right drive wheels 30, and a differential 40. The internal combustion engine 10 is a drive source for traveling. The internal combustion engine 10 has a crankshaft 11 as an output shaft. The detailed configuration of the internal combustion engine 10 will be described later.

[0010] The transmission unit 20 is on the power transmission path from the internal combustion engine 10 to each drive wheel 30. The transmission unit 20 includes a motor generator 21, a clutch 22, a torque converter 23, an automatic transmission 24, an oil pump 25, and a hydraulic unit 26.

[0011] The motor generator 21 is a so-called three-phase AC motor. The motor generator 21 has a rotating shaft 21A. The rotating shaft 21A is connected to the crankshaft 11 via the clutch 22. The motor generator 21 is connected to a battery 21C of the vehicle 500 via an inverter 21B of the vehicle 500. The motor generator 21 functions as an electric motor and a generator. When the motor generator 21 functions as an electric motor, it can apply positive torque to the crankshaft 11 with the power from the battery 21C. Also, when the motor generator 21 functions as a generator, the motor generator 21 can apply negative torque to the crankshaft 11 of the internal combustion engine 10. The motor generator 21 supplies power to the battery 21C when functioning as a generator.

[0012] The clutch 22 can be switched between an engaged state and a released state by hydraulic pressure. When the clutch 22 is in the engaged state, the above-described torque transmission is possible between the internal combustion engine 10 and the motor generator 21.

[0013] The torque converter 23 has a lock-up clutch 23A, an input shaft 23B, and an output shaft 23C. The input shaft 23B is connected to the opposite side of the clutch 22 on the rotating shaft 21A. The lock-up clutch 23A is interposed between the input shaft 23B and the output shaft 23C. The lock-up clutch 23A can be switched between an engaged state and a released state by hydraulic pressure. When the lock-up clutch 23A is in the engaged state, the input shaft 23B and the output shaft 23C rotate integrally. When the lock-up clutch 23A is in the engaged state, the torque converter 23 shifts the torque input to the input shaft 23B and outputs it from the output shaft 23C.

[0014] The automatic transmission 24 is connected to the output shaft 23C of the torque converter 23. That is, the automatic transmission 24 is connected to the crankshaft 11 via the torque converter 23. The automatic transmission 24 has a plurality of gear mechanisms and a plurality of engaging elements, although not shown in the figure. The engaging elements of the automatic transmission 24 are, for example, clutch mechanisms and brake mechanisms. The engaging state and the released state of each engaging element of the automatic transmission 24 can be switched by hydraulic pressure. By switching the engaging state and the released state of each engaging element, the automatic transmission 24 can form a gear stage corresponding to any one of four preset shift ranges. The four shift ranges are the parking range, the neutral range, the drive range, and the reverse range. The parking range and the neutral range are shift ranges that form non-driving gear stages of the vehicle 500. That is, the parking range and the neutral range are non-driving ranges that do not transmit torque to each drive wheel 30. The drive range and the reverse range are shift ranges that form driving gear stages of the vehicle 500. That is, the drive range and the reverse range are driving ranges that can transmit torque to each drive wheel 30. Note that "not transmitting torque to each drive wheel 30" includes not only the case where the torque transmitted to the drive wheel 30 is zero, but also the case where a slight torque that prevents the vehicle 500 from moving is transmitted to the drive wheel 30.

[0015] The oil pump 25 is an electric pump. The hydraulic pressure generated by the oil pump 25 is supplied to the transmission unit 20. Specifically, the hydraulic pressure generated from the oil pump 25 is supplied to the clutch 22, the torque converter 23, the lock-up clutch 23A, and the automatic transmission 24.

[0016] The hydraulic unit 26 has the hydraulic circuits of the clutch 22, the torque converter 23, the lock-up clutch 23A, and the automatic transmission 24, and various hydraulic control valves for controlling their operating hydraulic pressures. By controlling the hydraulic unit 26, for example, the engaged state and released state of each engaging element in the automatic transmission 24 are switched. Thereby, the gear stage in the automatic transmission 24 is changed, and a non-driving range or a driving range is selected. In FIG. 1, the illustration of the hydraulic circuit and the hydraulic control valve of the hydraulic unit 26 is omitted.

[0017] The differential 40 is connected to the automatic transmission 24 and each driving wheel 30. That is, the differential 40 is interposed between the transmission unit 20 and each driving wheel 30. The differential 40 distributes the torque output from the transmission unit 20 to the left and right driving wheels 30. The differential 40 allows a difference in rotational speed to occur between the left and right driving wheels 30.

[0018] <Configuration of Internal Combustion Engine> As shown in FIG. 2, the internal combustion engine 10 includes an intake passage 101, a throttle valve 102, and an exhaust passage 106. The intake passage 101 is a passage for the flow of intake air. The throttle valve 102 is located in the middle of the intake passage 101. The throttle valve 102 is a so-called butterfly valve. The throttle valve 102 adjusts the amount of intake air flowing through the intake passage 101. The exhaust passage 106 is a passage for the flow of exhaust gas.

[0019] The internal combustion engine 10 includes a crankshaft 11, a combustion chamber 12, a fuel injection valve 13, a piston 14, and a connecting rod 15. The combustion chamber 12 is a cylindrical space partitioned inside the internal combustion engine 10. The combustion chamber 12 is connected to an intake passage 101 and an exhaust passage 106. In FIG. 2, only one combustion chamber 12 is shown, but the internal combustion engine 10 includes a plurality of, for example, four combustion chambers 12. The fuel injection valve 13 is located near the combustion chamber 12. The fuel injection valve 13 injects fuel toward the combustion chamber 12. The piston 14 is located inside the combustion chamber 12. The piston 14 has a substantially cylindrical shape corresponding to the shape of the combustion chamber 12. The piston 14 is reciprocally movable inside the combustion chamber 12. The connecting rod 15 is connected to the piston 14. The crankshaft 11 is connected to the piston 14 via the connecting rod 15. The crankshaft 11 rotates in conjunction with the reciprocating movement of the piston 14.

[0020] Further, the internal combustion engine 10 includes an intake valve 16, an exhaust valve 17, and a spark plug 18. The intake valve 16 is located at the connection point between the combustion chamber 12 and the intake passage 101. When the intake valve 16 operates, the opening on the combustion chamber 12 side in the intake passage 101 is opened and closed. The exhaust valve 17 is located at the connection point between the combustion chamber 12 and the exhaust passage 106. When the exhaust valve 17 operates, the opening on the combustion chamber 12 side in the exhaust passage 106 is opened and closed. The spark plug 18 is located inside the combustion chamber 12. The spark plug 18 burns the air-fuel mixture that has flowed into the combustion chamber 12 by generating a spark discharge.

[0021] The vehicle 500 includes a catalyst 50. The catalyst 50 is a so-called three-way catalyst. The catalyst 50 is located in the middle of the exhaust passage 106. The catalyst 50 purifies the exhaust gas. As shown in FIG. 1, the vehicle 500 includes an air flow meter 61, a water temperature sensor 62, and a catalyst temperature sensor 63. As shown in FIG. 2, the air flow meter 61 is located in the middle of the intake passage 101. Specifically, the air flow meter 61 is located upstream of the throttle valve 102 in the intake passage 101 when viewed from the throttle valve 102. The air flow meter 61 detects the amount of air GA flowing into the internal combustion engine 10. The water temperature sensor 62 is located at the outlet of the water jacket partitioned inside the internal combustion engine 10. In FIG. 2, the illustration of the water jacket is omitted. The water temperature sensor 62 detects the cooling water temperature TW flowing through the water jacket. That is, the water temperature sensor 62 detects the cooling water temperature TW of the internal combustion engine 10. The catalyst temperature sensor 63 is located in the middle of the exhaust passage 106. Specifically, the catalyst temperature sensor 63 is located downstream of the catalyst 50 in the exhaust passage 106 when viewed from the catalyst 50. The catalyst temperature sensor 63 detects the temperature TMP of the exhaust flowing out of the catalyst 50 as the temperature TMP of the catalyst 50. The air flow meter 61, the water temperature sensor 62, and the catalyst temperature sensor 63 output signals according to the information they each detect.

[0022] As shown in FIG. 1, the vehicle 500 includes a control device 100. The control device 100 receives a signal regarding the amount of air GA detected by the air flow meter 61. The control device 100 receives a signal regarding the cooling water temperature TW detected by the water temperature sensor 62. The control device 100 receives a signal regarding the temperature TMP detected by the catalyst temperature sensor 63. Further, the control device 100 can calculate an integrated air amount GAS, which is an integrated value of the air amount GA since the internal combustion engine 10 is started.

[0023] The control device 100 controls the hydraulic unit 26 and the inverter 21B. As described above, the control device 100 changes the engaged state / released state of each engaging element in the automatic transmission 24 by controlling the hydraulic unit 26. Thereby, the gear stage in the automatic transmission 24 is changed, and either the non - driving range or the driving range is selected.

[0024] The control device 100 controls the inverter 21B to change the power generation amount of the motor generator 21. When the power generation amount of the motor generator 21 is increased, the negative torque acting on the crankshaft 11 increases. That is, when the power generation amount of the motor generator 21 is increased, the load on the internal combustion engine 10 increases.

[0025] The control device 100 is capable of executing a catalyst warm-up process that promotes the warm-up of the catalyst 50. The catalyst warm-up process is a process that increases the load on the internal combustion engine 10. Specifically, the control device 100 increases the load on the internal combustion engine 10 by increasing the power generation amount of the motor generator 21 by a specified amount with respect to the power generation amount of the motor generator 21 when the catalyst warm-up process is not being executed. As a result, the temperature of the exhaust gas passing through the exhaust passage 106 rises, and the warm-up of the catalyst 50 is promoted.

[0026] The control device 100 includes a first map and a second map as arithmetic maps for calculating the above-mentioned specified amount. The control device 100 stores a specified amount corresponding to the parameter in the first map. The parameters are the coolant temperature TW and the integrated air amount GAS. The control device 100 inputs the coolant temperature TW and the integrated air amount GAS into the first map to calculate the specified amount.

[0027] The control device 100 also stores a specified amount corresponding to the parameter in the second map in the same manner as in the first map. When the same parameters are input to the first map and the second map, the specified amount calculated from the second map is a larger value than the specified amount calculated from the first map.

[0028] The control device 100 can be configured as a circuitry including one or more processors that execute various processes according to a computer program (software). Note that the control device 100 may be configured as a circuitry including one or more dedicated hardware circuits such as an application specific integrated circuit (ASIC) that execute at least a part of the various processes, or a combination thereof. The processor includes a CPU and memories such as a RAM and a ROM. The memory stores program codes or instructions configured to cause the CPU to execute processes. The memory, that is, the computer-readable medium includes any available medium accessible by a general-purpose or dedicated computer.

[0029] <Regarding the load increase control executed by the control device> Hereinafter, the load increase control executed by the control device 100 will be described. The control device 100 executes the load increase control only once when the internal combustion engine 10 is started.

[0030] As shown in FIG. 3, when executing the load increase control, the control device 100 first executes the process of step S11. In step S11, the control device 100 receives a signal regarding the coolant temperature TW from the coolant temperature sensor 62. The control device 100 determines whether the coolant temperature TW is equal to or lower than a predetermined threshold value. This threshold value is predetermined by experiments and simulations as the coolant temperature TW when the amount of NOx or the like discharged from the exhaust passage 106 at the start of the internal combustion engine 10 becomes an acceptable upper limit value. If the coolant temperature TW is higher than the threshold value (S11: NO), the control device 100 determines that the catalyst warm-up process is unnecessary. Then, the control device 100 ends the load increase control. On the other hand, if the coolant temperature TW is equal to or lower than the threshold value (S11: YES), the control device 100 executes the catalyst warm-up process. Then, the process of the control device 100 proceeds to step S12.

[0031] In step S12, the control device 100 checks whether the driving range is being selected. That is, the control device 100 checks whether the vehicle 500 is in the drive range or the reverse range. Note that the shift range of the vehicle 500 can be confirmed by the control mode of the hydraulic pressure unit 26 of the control device 100. If it is in the driving range (S12: YES), the process of the control device 100 proceeds to step S13.

[0032] In step S13, the control device 100 selects the first map. Then, the control device 100 acquires the coolant temperature TW and the integrated air quantity GAS. The control device 100 applies the coolant temperature TW and the integrated air quantity GAS to the first map to calculate a specified quantity. After that, the process of the control device 100 proceeds to step S14.

[0033] In step S14, the control device 100 controls the inverter 21B to increase the power generation amount by the specified quantity. That is, the control device 100 increases the negative torque applied from the motor generator 21 to the crankshaft 11. After that, the process of the control device 100 proceeds to step S17.

[0034] On the other hand, if a negative determination is made in step S12 (S12: NO), the control device 100 determines that the non-driving range is being selected and proceeds to the process of step S15. In step S15, the control device 100 selects the second map. Then, the control device 100 acquires the coolant temperature TW and the integrated air quantity GAS. The control device 100 applies the coolant temperature TW and the integrated air quantity GAS to the second map to calculate a specified quantity. After that, the process of the control device 100 proceeds to step S16.

[0035] In step S16, the control device 100 controls the inverter 21B to increase the power generation amount by the specified quantity. That is, the control device 100 increases the negative torque applied from the motor generator 21 to the crankshaft 11. After that, the process of the control device 100 proceeds to step S17.

[0036] In step S17, the control device 100 first receives a signal regarding the temperature TMP from the catalyst temperature sensor 63. The control device 100 determines whether the temperature TMP is equal to or higher than a predetermined specified temperature. The specified temperature is set, for example, to the lower limit value of the temperature range in which the catalyst 50 is activated, or a temperature slightly higher than the lower limit value. If the temperature TMP is lower than the specified temperature (S17: NO), the process of the control device 100 proceeds to step S12. That is, in the case of a negative determination in step S17, the control device 100 re-executes the determination as to whether the driving range is being selected. On the other hand, if the temperature TMP is equal to or higher than the specified temperature (S17: YES), the control device 100 determines that the warm-up of the catalyst 50 is complete. Then, the control device 100 ends the series of load increase controls.

[0037] <Operation of this embodiment> In the vehicle 500, generally, the load on the internal combustion engine 10 is smaller during non-driving range selection than during driving range selection. Therefore, during non-driving range selection, it is more difficult to promote the warm-up of the catalyst 50 than during driving range selection.

[0038] On the other hand, when the control device 100 executes the load increase control, it calculates a specified amount that is the amount of power generation to be added. When the same parameters are input to the first map and the second map, the specified amount calculated from the second map becomes a larger value. That is, during non-driving range selection, the amount of power generation in the catalyst warm-up process becomes larger than during driving range selection.

[0039] <Effect of this embodiment> (1) In the above embodiment, during non-driving range selection, the amount of power generation of the motor generator 21 can be set larger than during driving range selection. Thereby, the difference between the load on the internal combustion engine 10 during non-driving range selection and the load on the internal combustion engine 10 during driving range selection can be reduced. That is, according to the above embodiment, even during non-driving range selection, sufficient warm-up performance of the catalyst 50 similar to that during driving range selection can be obtained.

[0040] (2) In the above embodiment, when the control device 100 determines that the warm-up of the catalyst 50 has not been completed during the load increase control, it executes the determination again as to whether or not the driving range is being selected. Therefore, even when the driving range and the non-driving range are switched before the warm-up of the catalyst 50 is completed, the control device 100 can calculate the specified amount suitable for each shift range.

[0041] <Modified Example> The above embodiments can be implemented with the following modifications. The above embodiments and the following modified examples can be implemented in combination within a technically non-conflicting range.

[0042] · In the load increase control, the control device 100 can omit the process of step S11. That is, when the internal combustion engine 10 starts, the control device 100 may always execute the load increase control. Also, the condition for determining whether or not to execute the catalyst warm-up process in step S11 is not limited to the example of the above embodiment.

[0043] · In step S17, the control device 100 may determine whether or not the warm-up of the catalyst 50 is completed using another condition. For example, the control device 100 may store in advance the correspondence between the integrated air amount GAS and the completion of the warm-up of the catalyst 50, and determine the completion of the warm-up of the catalyst 50 according to the value of the integrated air amount GAS. Also, for example, the control device 100 may determine that the warm-up of the catalyst 50 is completed on the condition that a specified time has elapsed since the start of the load increase control.

[0044] ·In calculating the specified amount, it is not always necessary to use the first map and the second map. For example, the control device 100 stores an arithmetic expression that outputs the specified amount with a value based on the coolant temperature TW and the air amount GA as input values, and the specified amount may be calculated using this arithmetic expression. However, in any method of calculating the specified amount, it is necessary to satisfy the relationship that if the input values are the same, the specified amount calculated during non-driving range selection is larger than that calculated during driving range selection. Also, the specified amount during non-driving range selection may be calculated by multiplying the specified amount calculated during driving range selection by a coefficient greater than 1 or adding a positive value.

[0045] ·The configuration of the automatic transmission 24 is not limited to the example of the above embodiment. The automatic transmission 24 only needs to be able to switch between a driving range and a non-driving range. ·The overall configuration of the vehicle 500 is not limited to the example of the above embodiment. The vehicle 500 only needs to include an internal combustion engine 10, a motor generator 21, an automatic transmission 24, a catalyst 50, an air flow meter 61, and a water temperature sensor 62.

Explanation of Signs

[0046] GAS…Integrated air amount TW…Coolant temperature 10…Internal combustion engine 11…Crankshaft 20…Transmission unit 21…Motor generator 24…Automatic transmission 50…Catalyst 61…Air flow meter 62…Water temperature sensor 100…Control device 500…Vehicle

Claims

【Claim 1】 An internal combustion engine having a crankshaft, a motor generator capable of applying torque to the crankshaft, a transmission connected to the crankshaft and capable of switching between a driving range in which torque can be transmitted to drive wheels and a non-driving range in which torque is not transmitted to the drive wheels, a catalyst located in the middle of the exhaust passage of the internal combustion engine for purifying exhaust gas, a water temperature sensor for detecting the cooling water temperature of the internal combustion engine, an air flow meter located in the middle of the intake passage of the internal combustion engine for detecting the amount of air flowing into the internal combustion engine, A control device applied to a vehicle comprising: Capable of executing a catalyst warming-up process for promoting warming-up of the catalyst, The catalyst warming-up process is a process of increasing the load of the internal combustion engine by increasing a specified amount calculated based on the air amount and the cooling water temperature with respect to the power generation amount of the motor generator when the catalyst warming-up process is not being executed, The specified amount calculated in the non-driving range is larger than the specified amount calculated in the driving range A control device for a vehicle.

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