Hybrid vehicles

Abstract

We provide hybrid vehicles that have a sufficient driving range for emergency exit maneuvers. [Solution] The system includes an engine and a motor which are the driving power source, first and second fuel pumps provided in a fuel tank which pressurize fuel and supply it to the engine, and a control device which drives the first fuel pump and stops the second fuel pump when the requested output of the engine that is being driven is below a threshold, and drives both the first and second fuel pumps when the requested output is greater than the threshold, the control device includes an acquisition unit which acquires the results of abnormality diagnosis of the first and second fuel pumps while the engine is being driven, a pump control unit which drives the other of the first and second fuel pumps while stopping the other when one of the first and second fuel pumps is diagnosed as abnormal, an engine control unit which limits the output of the engine to below the threshold when one of the pumps is diagnosed as abnormal, and a notification control unit which notifies the results of the abnormality diagnosis.

Description

Technical Field

[0001] The present invention relates to a hybrid vehicle.

Background Art

[0002] There are two fuel pumps provided in a fuel tank of a vehicle, which pressurize fuel in the fuel tank and supply it to an engine (see, for example, Patent Document 1).

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] Abnormal diagnosis may be performed on two fuel pumps. For example, when one of the two fuel pumps is diagnosed as abnormal, in a hybrid vehicle, it may be considered to stop the engine and perform retreat running by a motor. However, depending on the charge amount of the battery, there is a risk that the running distance of the retreat running cannot be ensured.

[0005] Therefore, an object of the present invention is to provide a hybrid vehicle in which the running distance of retreat running is ensured.

Means for Solving the Problems

[0006] The above objective can be achieved by a hybrid vehicle comprising: an engine and a motor as a driving power source; first and second fuel pumps provided in a fuel tank for pressurizing the fuel in the fuel tank and supplying it to the engine; a control device that drives the first fuel pump and stops the second fuel pump when the requested output of the engine being driven is below a threshold, and drives both the first and second fuel pumps when the requested output is greater than the threshold, wherein the control device includes an acquisition unit for acquiring the results of abnormality diagnosis of the first and second fuel pumps while the engine is running; a pump control unit that drives the other of the first and second fuel pumps while stopping the first when one of the first and second fuel pumps is diagnosed as abnormal; an engine control unit that limits the output of the engine to below the threshold when one of the pumps is diagnosed as abnormal; and a notification control unit for notifying the results of the abnormality diagnosis.

[0007] The engine control unit may, if it diagnoses that one of the above is abnormal, limit the output of the engine to below the threshold by controlling the amount of intake air from the engine.

[0008] The pump control unit may, if it diagnoses that one of the pumps is abnormal, provide feedback control to the fuel discharge flow rate of the other pump based on the difference between the target fuel pressure and the actual fuel pressure of the fuel supplied to the engine.

[0009] The control device may include a driving control unit that, when both the first and second fuel pumps are diagnosed as malfunctioning, stops the engine and drives the hybrid vehicle using the motor.

[0010] The engine may also include a third fuel pump that further pressurizes the fuel pressurized by the first and second fuel pumps, and the engine may have port injection valves and in-cylinder injection valves, with the first and second fuel pumps supplying fuel to the port injection valves and the third fuel pump supplying fuel to the in-cylinder injection valves. [Effects of the Invention]

[0011] According to the present invention, it is possible to provide a hybrid vehicle that ensures a sufficient distance for emergency exit driving. [Brief explanation of the drawing]

[0012] [Figure 1] This is a schematic diagram of a hybrid vehicle. [Figure 2] This is a schematic diagram of the fuel supply system. [Figure 3] This is a flowchart illustrating abnormal driving control. [Modes for carrying out the invention]

[0013] [Overall configuration of a hybrid vehicle] Figure 1 is a schematic diagram of the hybrid vehicle 1. The hybrid vehicle 1 is equipped with an engine 10 and a motor 15 as the power source for driving. The engine 10 is an inline 4-cylinder gasoline engine, but is not limited to 4 cylinders; it may be a V-type engine or a diesel engine. A transmission unit 11 is provided in the power transmission path from the engine 10 to the drive wheels 13. The transmission unit 11 and the left and right drive wheels 13 are driven together via a differential gear 12.

[0014] The transmission unit 11 is equipped with a K0 clutch 14 and a motor 15. The motor 15 is located on the power transmission path from the engine 10 to the drive wheels 13.

[0015] The K0 clutch 14 is located between the engine 10 and the motor 15 in the power transmission path. The K0 clutch 14 engages when hydraulic pressure is supplied, connecting the power transmission between the engine 10 and the motor 15. The K0 clutch 14 disengages when the hydraulic pressure supply is stopped, interrupting the power transmission between the engine 10 and the motor 15. The K0 clutch 14 also slips from the start of torque transmission until it is fully engaged.

[0016] The motor 15 is connected to the battery 16 via an inverter 17. The battery 16 is a rechargeable secondary battery such as a nickel-metal hydride battery or a lithium-ion battery. The motor 15 functions as a motor that generates driving force for the vehicle in response to power supplied from the battery 16. Furthermore, the motor 15 also functions as a generator that generates electricity to charge the battery 16 in response to power transmission from the engine 10 and the drive wheels 13. The power exchanged between the motor 15 and the battery 16 is regulated by the inverter 17.

[0017] The transmission unit 11 is equipped with a torque converter 18 and an automatic transmission 19. The torque converter 18 is a fluid coupling with a torque amplification function. The automatic transmission 19 is a multi-stage transmission that switches the gear ratio in multiple stages. The torque converter 18 is installed between the motor 15 and the drive wheels 13 on the power transmission path. The automatic transmission 19 is installed between the torque converter 18 and the drive wheels 13 on the power transmission path. The torque converter 18 is equipped with a lock-up clutch (hereinafter referred to as LU clutch) 20 that receives hydraulic pressure, engages with it to directly connect the motor 15 and the automatic transmission 19.

[0018] The LU clutch 20 engages when hydraulic pressure is supplied, connecting the power transmission between the motor 15 and the drive wheels 13. The LU clutch 20 disengages when the hydraulic pressure supply is stopped. The LU clutch 20 also slips from disengagement until it engages again.

[0019] The transmission unit 11 is further equipped with an oil pump 21 and a hydraulic control mechanism 22. The hydraulic pressure generated by the oil pump 21 is supplied to the K0 clutch 14, torque converter 18, automatic transmission 19, and LU clutch 20 via the hydraulic control mechanism 22. The hydraulic control mechanism 22 is equipped with hydraulic circuits for the K0 clutch 14, torque converter 18, automatic transmission 19, and LU clutch 20, as well as various hydraulic control valves for controlling their operating hydraulic pressures.

[0020] The hybrid vehicle 1 is provided with an ECU (Electronic Control Unit) 100 as a control device for the hybrid vehicle. The ECU 100 is an electronic control unit including an arithmetic processing circuit that performs various arithmetic processes related to the running control of the vehicle, and a memory that stores control programs and data. The ECU 100 is an example of a control device, and specifically, functionally realizes an acquisition unit, a pump control unit, an engine control unit, a notification control unit, and a running control unit, which will be described later in detail.

[0021] An ignition switch 61, a crank angle sensor 62, an air flow meter 63, and a display 65 are connected to the ECU 100. The ignition switch ills 61 detects the on / off state of the ignition. The crank angle sensor 62 detects the rotational speed of the crankshaft of the engine 10. The air flow meter 63 detects the amount of intake air introduced into the engine 10. The display 65 is provided, for example, on the instrument panel of the hybrid vehicle 1.

[0022] The ECU 100 controls the driving of the engine 10 and the motor 15. Specifically, the ECU 100 controls the inverter 17 to adjust the amount of power transfer between the motor 15 and the battery 16, thereby performing torque control of the motor 15. The ECU 100 controls the driving of the K0 clutch 14, the LU clutch

[0023] 20, and the automatic transmission 19 through the control of the hydraulic control mechanism 22.

[0023] The ECU 100 runs the hybrid vehicle 1 in either the motor running mode or the hybrid running mode. In the motor running mode, the ECU 100 disengages the K0 clutch 14 and rotates the drive wheels 13 with the power of the motor 15. In the hybrid running mode, the ECU 100 engages the K0 clutch 14 and rotates the drive wheels 13 with the power of at least one of the engine 10 and the motor 15. For example, when the required driving force for the hybrid vehicle 1 becomes greater than or equal to the driving force threshold value, the mode is switched from the motor running mode to the hybrid running mode. Also, when the charge amount of the battery 16 becomes less than or equal to the power threshold value, the mode is switched from the motor running mode to the hybrid running mode.

[0024] [Outline configuration of the fuel supply system] Figure 2 is a schematic diagram of the fuel supply system A. The fuel supply system A includes an engine 10, a fuel tank 23, a main fuel pump 24a, a sub-fuel pump 24b, a low-pressure pipe 25, a low-pressure delivery pipe 26, a high-pressure delivery pipe 36, fuel pressure sensors 28 and 38, and a high-pressure pump 40, etc.

[0025] Engine 10 is a spark-ignition type four-cylinder gasoline engine equipped with in-cylinder injection valves 37 that inject fuel into each cylinder and port injection valves 27 that inject fuel into each intake port. Engine 10 also includes a camshaft CPS that drives the intake valve or exhaust valve in conjunction with a crankshaft which is linked to a plurality of pistons.

[0026] The fuel tank 23 stores gasoline, which is the fuel. The main fuel pump 24a and the sub-fuel pump 24b are located inside the fuel tank 23. The main fuel pump 24a and the sub-fuel pump 24b are pumps with the same performance, such as head, but are not limited to these. The main fuel pump 24a pressurizes the fuel and discharges it to the low-pressure pipe 25 via the branch pipe 24ap. The sub-fuel pump 24b pressurizes the fuel and discharges it to the low-pressure pipe 25 via the branch pipe 24bp. The base ends of the branch pipes 24ap and 24bp are connected to the main fuel pump 24a and the sub-fuel pump 24b, respectively. The ends of the branch pipes 24ap and 24bp are connected to the low-pressure pipe 25. The fuel discharged into the low-pressure pipe 25 is supplied to the port injection valve 27 via the low-pressure delivery pipe 26, and also to the high-pressure pump 40 via the branch pipe 25a that branches off from the low-pressure pipe 25.

[0027] The high-pressure pump 40 pressurizes the fuel supplied from the branch pipe 25a and discharges it into the high-pressure delivery pipe 36. The fuel pressurized by the high-pressure pump 40 is supplied to the in-cylinder injection valve 37 via the high-pressure delivery pipe 36.

[0028] The fuel pressure sensors 28 and 38 detect the fuel pressure in the low-pressure delivery pipe 26 and the high-pressure delivery pipe 36, respectively. The ECU 100 acquires the detected values ​​from the fuel pressure sensors 28 and 38.

[0029] Furthermore, the ECU 100 changes the in-cylinder injection ratio, which is the ratio of the amount of fuel injected from the in-cylinder injection valve 37 to the total amount of fuel injected, according to the operating range of the engine 10. For example, when the engine 10 is operating in a low-load range, the in-cylinder injection ratio is 0%, in a high-load range it is 100%, and in a medium-load range it is set to an intermediate value.

[0030] The high-pressure pump 40 is equipped with a cylinder 41, a plunger 42, a pressurizing chamber 43, an intake passage 45, a discharge passage 47, a relief passage 49, an intake valve 50, a discharge valve 60, and a relief valve 70. The plunger 42 is biased by a spring toward the cam CP, which rotates together with the cam shaft CPS, and reciprocates within the cylinder 41 as the cam CP rotates. The pressurizing chamber 43 is defined by the cylinder 41 and the plunger 42. The volume of the pressurizing chamber 43 decreases as the plunger 42 rises. The volume of the pressurizing chamber 43 increases as the plunger 42 descends.

[0031] The intake passage 45 connects the branch pipe 25a, which branches off from the low-pressure pipe 25, to the pressurizing chamber 43. The intake passage 45 is provided with a pulsation damper 44 to suppress fuel pressure pulsation. The relief passage 49 connects the pressurizing chamber 43 to the high-pressure delivery pipe 36. The discharge passage 47 connects the relief passage 49 on the pressurizing chamber 43 side of the discharge valve 60 to the relief passage 49 on the high-pressure delivery pipe 36 side of the discharge valve 60.

[0032] The intake valve 50 is located on the fuel inlet side of the pressurizing chamber 43 and switches the communication state between the intake passage 45 and the pressurizing chamber 43. The intake valve 50 has a valve body 51, a coil 55 that drives the valve body 51, and a spring 53 that always biases the valve body 51 in the open direction. When the coil 55 is energized, the valve body 51 blocks the intake passage 45 and the pressurizing chamber 43 against the biasing force of the spring 53. When the coil 55 is not energized, the valve body 51 is maintained in the open state by the biasing force of the spring 53. The discharge valve 60 is located on the discharge passage 47 and is a check valve that allows the flow of fuel from the pressurizing chamber 43 side to the high-pressure delivery pipe 36 side but restricts the flow in the reverse direction.

[0033] During the intake stroke of the high-pressure pump 40, the intake valve 50 opens and the plunger 42 descends, filling the pressurizing chamber 43 from the branch pipe 25a through the intake passage 45. During the pressurizing stroke, the intake valve 50 closes and the volume of the pressurizing chamber 43 decreases as the plunger 42 rises, pressurizing the fuel in the pressurizing chamber 43. During the discharge stroke, the discharge valve 60 opens when the fuel pressure acting on the discharge valve 60 from the pressurizing chamber 43 side becomes greater due to the fuel pressure acting on the discharge valve 60 from the high-pressure delivery pipe 36 side and the biasing force of the discharge valve 60's spring. As a result, the pressurized fuel is supplied to the high-pressure delivery pipe 36.

[0034] The relief valve 70 is located on the relief passage 49 and allows fuel to flow from the high-pressure delivery pipe 36 to the pressurizing chamber 43, but restricts flow in the reverse direction. The relief valve 70 opens when the fuel pressure in the high-pressure delivery pipe 36 rises excessively, to the point where it could cause abnormalities in the high-pressure delivery pipe 36 or the in-cylinder injection valve 37.

[0035] The ECU 100 drives only the main fuel pump 24a when the requested output to the engine 10 is below a threshold. If the requested output to the engine 10 is greater than the threshold, the ECU 100 drives both the main fuel pump 24a and the sub-fuel pump 24b. By driving both the two main fuel pumps 24a and the sub-fuel pump 24b, the amount of fuel supplied to the port injection valves 27 of the engine 10 can be ensured. The main fuel pump 24a and the sub-fuel pump 24b are examples of the first and second fuel pumps, respectively. The high-pressure pump 40 is an example of the third fuel pump.

[0036] For example, when only the main fuel pump 24a is driven, the target discharge flow rate of the main fuel pump 24a is calculated according to the requested output of the engine 10, and the discharge flow rate of the main fuel pump 24a is feedback controlled based on the deviation between the target fuel pressure, which is the target value of the fuel pressure supplied to the port injection valve 27, and the actual fuel pressure. The actual fuel pressure supplied to the port injection valve 27 is obtained based on the fuel pressure sensor 28. When both the main fuel pump 24a and the sub-fuel pump 24b are driven, the target discharge flow rates of the main fuel pump 24a and the sub-fuel pump 24b are calculated according to the requested output of the engine 10, the discharge flow rate of the main fuel pump 24a is controlled to a predetermined fixed value, and only the discharge flow rate of the sub-fuel pump 24b is feedback controlled based on the deviation described above.

[0037] The ECU 100 performs abnormality diagnosis of the main fuel pump 24a and sub-fuel pump 24b when abnormality diagnosis conditions are met while driving in hybrid driving mode. The abnormality diagnosis of the main fuel pump 24a is based on whether the voltage and current values ​​applied to the main fuel pump 24a while it is running are within the normal range. For example, if at least one of the voltage and current values ​​applied to the main fuel pump 24a is outside the normal range, the main fuel pump 24a is diagnosed as abnormal. Similarly, the abnormality diagnosis of the sub-fuel pump 24b is based on whether the voltage and current values ​​applied to the sub-fuel pump 24b while it is running are within the normal range. Abnormality diagnosis conditions include, for example, that the operating state of the engine 10 is not transient or that the engine 10 has finished warming up.

[0038] [Abnormal Driving Control] Figure 3 is a flowchart illustrating abnormal driving control. The ECU 100 determines whether or not it is in hybrid driving mode (step S1). In other words, the ECU 100 determines whether or not it is running on engine 10. If the answer in step S1 is No, this control is terminated. If the answer in step S1 is Yes, the ECU 100 obtains the results of the abnormality diagnosis of the main fuel pump 24a and the sub-fuel pump 24b (step S2). Step S2 is an example of the processing performed by the acquisition unit.

[0039] Based on the results of the abnormality diagnosis, the ECU 100 determines whether both the main fuel pump 24a and the sub-fuel pump 24b have been diagnosed as abnormal (step S3). If the answer in step S3 is Yes, the ECU 100 switches to motor driving mode (step S4). As a result, the engine 10 stops, the driving of the main fuel pump 24a and the sub-fuel pump 24b also stops, and the vehicle switches to driving using the motor 15. Step S4 is an example of the process performed by the driving control unit. Next, the ECU 100 notifies the driver of the diagnosis result that both the main fuel pump 24a and the sub-fuel pump 24b are abnormal (step S5). The ECU 100 may notify the driver by displaying the diagnosis result on the display 65, for example, or by using a speaker. This allows the driver to drive the hybrid vehicle 1 in motor driving mode to avoid accidents.

[0040] If the answer in step S3 is No, the ECU 100 determines, based on the abnormality diagnosis result, whether only one of the main fuel pump 24a or the sub-fuel pump 24b was diagnosed as abnormal (step S6). If the answer in step S6 is No, both the main fuel pump 24a and the sub-fuel pump 24b are normal and this control is terminated.

[0041] If the answer in step S6 is Yes, the ECU 100 stops one of the main fuel pumps 24a and sub-fuel pumps 24b that was diagnosed as abnormal, and drives the other of the main fuel pumps 24a and sub-fuel pumps 24b that were not diagnosed as abnormal (step S7). Furthermore, the discharge flow rate of the other of the main fuel pumps 24a and sub-fuel pumps 24b that were not diagnosed as abnormal is also controlled by feedback based on the deviation between the target fuel pressure, which is the target value of the fuel pressure supplied to the port injection valve 27, and the actual fuel pressure, as described above. This allows the discharge flow rate of the other of the main fuel pumps 24a and sub-fuel pumps 24b that were not diagnosed as abnormal to be accurately converged to a target discharge flow rate corresponding to the engine 10's required output. Step S7 is an example of the processing performed by the pump control unit.

[0042] Furthermore, the ECU 100 limits the output of the engine 10 to below the threshold described above (step S8). The threshold is, as described above, the threshold used to switch between a state in which only the main fuel pump 24a is driven and a state in which both the main fuel pump 24a and the sub-fuel pump 24b are driven. By limiting the output of the engine 10 to below the threshold, the output of the engine 10 can be controlled to suit the operation of only the other of the main fuel pump 24a and the sub-fuel pump 24b that has not been diagnosed as abnormal. The limiting of the output of the engine 10 is achieved by limiting the intake air volume of the engine 10 to below the amount of air corresponding to the threshold described above. In this way, the output of the engine 10 can be limited by a simple method. Step S8 is an example of the processing performed by the engine control unit. Next, the ECU 100 notifies the driver of the diagnosis that only one of the main fuel pump 24a and the sub-fuel pump 24b is abnormal via the display 65 or speaker (step S5).

[0043] As described above, if only one of the main fuel pump 24a or the sub-fuel pump 24b is diagnosed as malfunctioning, the engine 10 continues to run, and the driver is able to move to safety. For example, if the vehicle were to switch to motor-driven mode in such a case, there is a risk that the distance for moving to safety may not be secured depending on the charge level of the battery 16. In this embodiment, the engine 10 continues to run by driving the other of the main fuel pump 24a and the sub-fuel pump 24b that has not been diagnosed as malfunctioning, and the distance for moving to safety is secured.

[0044] Although embodiments of the present invention have been described in detail above, the present invention is not limited to these specific embodiments, and various modifications and changes are possible within the scope of the gist of the present invention as described in the claims. [Explanation of Symbols]

[0045] 1. Hybrid vehicle 10 Engines 15 Motor 24a Main fuel pump (1st fuel pump) 24b Sub-fuel pump (second fuel pump) 27-port injection valve 37 In-cylinder injection valve 40. High-pressure pump (third fuel pump) 100 ECUs (Control Unit, Acquisition Unit, Pump Control Unit, Engine Control Unit, Notification Control Unit, Driving Control Unit)

Claims

1. The engine and motor are the power sources for propulsion, First and second fuel pumps are provided in the fuel tank and pressurize the fuel in the fuel tank to supply it to the engine. The system includes a control device that drives the first fuel pump and stops the second fuel pump when the requested output of the engine, which is currently running, is below a threshold, and drives both the first and second fuel pumps when the requested output is greater than the threshold, The control device is An acquisition unit that acquires the results of abnormality diagnosis of the first and second fuel pumps while the engine is running, A pump control unit that, when one of the first and second fuel pumps is diagnosed as malfunctioning, stops the first one while driving the other of the first and second fuel pumps, If one of the above is diagnosed as abnormal, an engine control unit limits the output of the engine to below the threshold, Includes a notification control unit that notifies the result of the abnormality diagnosis, Hybrid vehicle.

2. The hybrid vehicle according to claim 1, wherein the engine control unit, when it is determined that one of the above is abnormal, controls the amount of intake air from the engine to limit the output of the engine to below the threshold.

3. The hybrid vehicle according to claim 2, wherein the pump control unit, when it is determined that one of the pumps is abnormal, provides feedback control to the fuel discharge flow rate of the other pump based on the difference between the target fuel pressure and the actual fuel pressure of the fuel supplied to the engine.

4. The hybrid vehicle according to claim 3, wherein the control device includes a driving control unit that stops the engine and drives the hybrid vehicle using the motor when both the first and second fuel pumps are diagnosed as abnormal.

5. The system includes a third fuel pump that further pressurizes the fuel pressurized by the first and second fuel pumps, The engine has port injection valves and in-cylinder injection valves, The first and second fuel pumps supply fuel to the port injection valves, The hybrid vehicle according to claim 4, wherein the third fuel pump supplies fuel to the in-cylinder injection valve.

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