Control device

Abstract

To accurately determine an engine stall.SOLUTION: This control device is used for a hybrid vehicle capable of traveling by power from an engine and a motor, and determines abnormality of the engine, and determines whether or not the engine stall is caused based on engine speed when a stop request of fuel injection of the engine is made. As a result, the engine stall can be accurately determined.SELECTED DRAWING: Figure 3

Description

[Technical Field]

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

[0002] Conventionally, one proposed control device of this type is used in a hybrid vehicle that can run on power from an engine and a motor, and determines whether an engine abnormality has occurred (see, for example, Patent Document 1). This device determines whether the engine speed has fallen below a predetermined stall speed, and determines that an engine stall has occurred when the number of times the engine speed has fallen below the stall speed exceeds a threshold value. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Publication No. 2023-133998 Summary of the Invention [Problem to be solved by the invention]

[0004] When the above-mentioned control device is used in a hybrid vehicle that stops the engine when the engine speed exceeds a value of 0 when the engine is stopped, it is not possible to distinguish whether the engine stop is due to normal processing, such as when the accelerator pedal is released, or whether it is due to an engine stall, and it is not possible to accurately determine whether the engine stall has occurred.

[0005] The control device of the present disclosure has a primary object to accurately determine engine stall. [Means for solving the problem]

[0006] The control device of the present disclosure employs the following means to achieve the above-mentioned main object.

[0007] The control device of the present disclosure includes: A control device used in a hybrid vehicle that can run on power from an engine and a motor, the control device stopping the engine when the rotation speed of the engine exceeds a value of 0, Whether or not an engine stall has occurred is determined based on the engine speed when a request to stop fuel injection of the engine is made. The gist of this is as follows.

[0008] The control device disclosed herein determines whether an engine stall has occurred based on the engine speed when a request to stop engine fuel injection is made. The engine speed when a request to stop engine fuel injection is made differs between when the engine stall is caused by normal processing and when the engine stall is made. Therefore, by determining whether an engine stall has occurred based on the engine speed when a request to stop engine fuel injection is made, it is possible to accurately determine whether an engine stall has occurred.

[0009] In the control device of the present disclosure, when the stop request is made and the engine speed is equal to or lower than a predetermined speed, it may be determined that an engine stall has occurred. When the engine is stopped due to an engine stall, the engine speed is often equal to or lower than the predetermined speed. Therefore, by determining that an engine stall has occurred when the engine speed is lower than the predetermined speed when a request to stop engine fuel injection is made, an engine stall can be determined more accurately. The "predetermined speed" may be a speed lower than the lower limit of the speed at which it can be determined that the engine is completely combusting. [Brief explanation of the drawings]

[0010] [Figure 1] 1 is a diagram showing an outline of the configuration of a hybrid vehicle 20 equipped with a control device according to the present embodiment. [Figure 2] 4 is a flowchart showing an example of a determination routine executed by the engine ECU 24. [Figure 3]10 is a timing chart for explaining the relationship between the rotation speed Nstop and the timing of a request to stop fuel injection when the engine 22 is normal. [Figure 4] 10 is a timing chart for explaining the relationship between the rotation speed Nstop and the timing of a request to stop fuel injection when an engine stall occurs. DETAILED DESCRIPTION OF THE INVENTION

[0011] An embodiment of the present disclosure will be described with reference to the drawings. Fig. 1 is a schematic diagram showing the configuration of a hybrid vehicle 20 equipped with a control device of the present embodiment. As shown in Fig. 1, the hybrid vehicle 20 of the present embodiment includes an engine 22, an engine electronic control unit (hereinafter referred to as "engine ECU") 24, a planetary gear 30, motors MG1 and MG2 (first and second motors), a motor electronic control unit (hereinafter referred to as "motor ECU") 40, inverters 41 and 42, a battery 50 as an electricity storage device, and a hybrid electronic control unit (hereinafter referred to as HVECU) 70. Here, the engine ECU 24 corresponds to the control device.

[0012] The engine 22 is configured as a four-cylinder internal combustion engine that uses fuel such as gasoline or diesel oil and outputs power through four strokes: intake, compression, expansion (explosive combustion), and exhaust. The operation of the engine 22 is controlled by an engine ECU 24.

[0013] Although not shown, the engine ECU 24 is configured as a microprocessor centered on a CPU. In addition to the CPU, the engine ECU 24 includes a ROM for storing processing programs, a RAM for temporarily storing data, a flash memory for storing and retaining data, input / output ports, and a communication port. Signals from various sensors required for controlling the operation of the engine 22 are input to the engine ECU 24 via an input port. Examples of signals input to the engine ECU 24 include a crank angle θcr from a crank position sensor that detects the rotational position of the crankshaft 23 of the engine 22. Various control signals for controlling the operation of the engine 22 are output from the engine ECU 24 via an output port. Examples of signals output from the engine ECU 24 include a control signal for a throttle valve and a control signal for a fuel injection valve 126. The engine ECU 24 is connected to the HVECU 70 via a communication port. The engine ECU 24 calculates the engine speed Ne of the engine 22 based on the crank angle θcr of the engine 22 from the crank position sensor 140.

[0014] The planetary gear 30 is configured as a single-pinion type planetary gear mechanism. A rotor of a motor MG1 is connected to a sun gear of the planetary gear 30. A drive shaft 36, which is coupled to drive wheels 39a, 39b via a differential gear 38, is connected to a ring gear of the planetary gear 30. A crankshaft 23 of the engine 22 is connected to a carrier of the planetary gear 30 via a damper 28.

[0015] The motor MG1 is configured as, for example, a synchronous generator motor, and as described above, its rotor is connected to the sun gear of the planetary gear 30. The motor MG2 is configured as, for example, a synchronous generator motor, and its rotor is connected to the drive shaft 36. The inverters 41 and 42 are used to drive the motors MG1 and MG2, and are connected to the battery 50 via a power line 54. The motors MG1 and MG2 are rotationally driven by the motor ECU 40 controlling the switching of a plurality of switching elements (not shown) of the inverters 41 and 42.

[0016] The motor ECU 40 is configured as a microprocessor centered around a CPU (not shown). In addition to the CPU, the motor ECU 40 includes a ROM for storing processing programs, a RAM for temporarily storing data, a flash memory for storing and retaining data, input / output ports, and a communication port. Signals from various sensors required for driving and controlling the motors MG1 and MG2 are input to the motor ECU 40 via the input port. Examples of signals input to the motor ECU 40 include the rotational positions θm1 and θm2 of the rotors of the motors MG1 and MG2 from rotational position sensors (not shown) that detect the rotational positions of the rotors of the motors MG1 and MG2, and the phase currents Iu1, Iv1, Iu2, and Iv2 of the motors MG1 and MG2 from current sensors (not shown) that detect the phase currents flowing through the phases of the motors MG1 and MG2. The motor ECU 40 outputs switching control signals and other signals to multiple switching elements (not shown) of the inverters 41 and 42 via the output port. The motor ECU 40 is connected to the HVECU 70 via the communication port. The motor ECU 40 calculates the electrical angles θe1, θe2 and rotation speeds Nm1, Nm2 of the motors MG1, MG2 based on the rotational positions θm1, θm2 of the rotors of the motors MG1, MG2 from the rotational position sensors.

[0017] Battery 50 is configured as, for example, a lithium ion secondary battery or a nickel-metal hydride secondary battery, and as described above, is connected to inverters 41, 42 via power line 54. Battery 50 is managed by a battery electronic control unit (hereinafter referred to as "battery ECU") 52.

[0018] Although not shown, the battery ECU 52 is configured as a microprocessor centered on a CPU. In addition to the CPU, the battery ECU 52 includes a ROM for storing processing programs, a RAM for temporarily storing data, a flash memory for storing and retaining data, an input / output port, and a communication port. Signals from various sensors required for managing the battery 50 are input to the battery ECU 52 via the input port. Examples of signals input to the battery ECU 52 include the voltage Vb of the battery 50 from a voltage sensor (not shown) attached between the terminals of the battery 50, the current Ib of the battery 50 from a current sensor (not shown) attached to the output terminals of the battery 50, and the temperature Tb of the battery 50 from a temperature sensor (not shown) attached to the battery 50. The battery ECU 52 is connected to the HVECU 70 via the communication port. The battery ECU 52 calculates the state of charge (SOC) of the battery 50 based on the integrated value of the current Ib of the battery 50 from the current sensor. The state of charge (SOC) is the ratio of the amount of power that can be discharged from the battery 50 to the total capacity of the battery 50.

[0019] Although not shown, the HVECU 70 is configured as a microprocessor centered around a CPU. In addition to the CPU, the HVECU 70 includes a ROM for storing processing programs, a RAM for temporarily storing data, a flash memory for storing and retaining data, input / output ports, and communication ports. Signals from various sensors are input to the HVECU 70 via the input ports. Examples of signals input to the HVECU 70 include an ignition signal from an ignition switch 80 and a shift position SP from a shift position sensor 82 that detects the operating position of a shift lever 81. Other examples of signals input to the HVECU 70 include an accelerator opening Acc from an accelerator pedal position sensor 84 that detects the amount of depression of an accelerator pedal 83, a brake pedal position BP from a brake pedal position sensor 86 that detects the amount of depression of a brake pedal 85, and a vehicle speed V from a vehicle speed sensor 88. As described above, the HVECU 70 is connected to the engine ECU 24, the motor ECU 40, and the battery ECU 52 via the communication ports.

[0020] In the hybrid vehicle 20 of this embodiment configured as described above, the engine 22, motors MG1 and MG2, and step-up / step-down converter 46 are controlled by cooperative control between the HVECU 70, engine ECU 24, and motor ECU 40 so that the vehicle runs in a hybrid driving (HV driving) mode with the engine 22 running, or in an electric driving (EV driving) mode with the engine 22 stopped.

[0021] In the HV driving mode, the HVECU 70 first sets the driving torque Tr* required of the drive shaft 36 based on the accelerator opening Acc and the vehicle speed V, and then multiplies the driving torque Tr* by the rotation speed Nd of the drive shaft 36 (the rotation speed Nm2 of the motor MG2) to set the driving power Pr* required of the drive shaft 36. Next, the HVECU 70 subtracts the charging / discharging power requirement Pb* (which is a positive value when the battery 50 is discharging) based on the power storage percentage SOC of the battery 50 from the driving power Pr* to set the driving power requirement Pe* required of the engine 22. The engine ECU 24 then sets a target rotation speed Ne* and target torque Te* for the engine 22 and torque commands Tm1* and Tm2* for the motors MG1 and MG2 so that the engine 22 outputs a required power Pe* and a running torque Tr* to the drive shaft 36. The engine ECU 24 transmits the target rotation speed Ne* and target torque Te* for the engine 22 to the engine ECU 24, and transmits the torque commands Tm1* and Tm2* for the motors MG1 and MG2 to the motor ECU 40. The engine ECU 24 performs operation control (intake air amount control, fuel injection control, ignition control, etc.) for the engine 22 so that the engine 22 operates based on the target rotation speed Ne* and target torque Te*. The motor ECU 40 performs switching control of multiple switching elements of the inverters 41 and 42 so that the motors MG1 and MG2 are driven by the torque commands Tm1* and Tm2*.

[0022] In the EV driving mode, the HVECU 70 sets the driving torque Tr* in the same manner as in the HV driving mode, sets the torque command Tm1* of the motor MG1 to the value 0, and sets the torque command Tm2* of the motor MG2 so that the driving torque Tr* is output to the drive shaft 36. The torque commands Tm1* and Tm2* of the motors MG1 and MG2 are sent to the motor ECU 40. The control of the inverters 41 and 42 by the motor ECU 40 has been described above.

[0023] Furthermore, in the hybrid vehicle 20 of this embodiment, when the required power Pe* is set to a value of 0 while the vehicle is traveling in the HV traveling mode, engine stop control is executed to stop the operation of the engine 22. In the engine stop control, the HVECU 70 transmits a request to stop the engine 22 to the engine ECU 24 and controls the motor MG1 so that the rotation speed Ne of the engine 22 decreases toward the value of 0. Upon receiving the stop request, the engine ECU 24 determines that a request to stop fuel injection, ignition, and the like of the engine 22 has been made, and stops fuel injection of the engine 22 and stops other controls for operating the engine 22, such as ignition control.

[0024] Furthermore, in the hybrid vehicle 20 of this embodiment, if any abnormality occurs in the engine 22 while the vehicle is running in the HV running mode, the above-described engine stop control is executed.

[0025] Next, the operation of the hybrid vehicle 20 equipped with the control device of this embodiment, particularly the operation when determining whether or not an engine stall has occurred, will be described. Figure 2 is a flowchart showing an example of a determination routine executed by the engine ECU 24. This routine is executed when the engine ECU 24 receives a request to stop the engine 22 from the HVECU 70.

[0026] When this routine is executed, the CPU of the engine ECU 24 executes a process (S100) to set the rotation speed Nstop of the engine 22 when a request to stop fuel injection of the engine 22 is made. The rotation speed Nstop is set to the rotation speed Ne of the engine 22 when the request to stop the engine 22 is received.

[0027] Then, it is determined whether the rotation speed Nstop is equal to or less than a predetermined rotation speed Neref (S110). The predetermined rotation speed Neref can be set to a rotation speed (e.g., 300 rpm) lower than the lower limit value Nmin (e.g., 800 rpm) of the rotation speed at which it can be determined that the engine 22 is in a complete combustion state.

[0028] When the rotation speed Ne of the engine 22 exceeds a predetermined rotation speed Neref, the engine 22 is determined to be normal (S120), and when the rotation speed Ne of the engine 22 is equal to or less than the predetermined rotation speed Neref, the engine 22 is determined to have stalled (S130), and this routine is terminated.

[0029] FIG. 3 is a timing chart illustrating the relationship between the rotation speed Nstop and the timing of a request to stop fuel injection when the engine 22 is normal. FIG. 4 is a timing chart illustrating the relationship between the rotation speed Nstop and the timing of a request to stop fuel injection when an engine stall occurs. When the engine 22 is normal, as shown in FIG. 3, an engine stop request, i.e., a request to stop fuel injection, is made within the range of rotation speeds at which the engine 22 operates normally (time t1; therefore, the rotation speed Nstop is equal to or higher than the lower limit value Nmin). When an engine stall occurs, as shown in FIG. 4, an engine stop request, i.e., a request to stop fuel injection, is made when the rotation speed Ne of the engine 22 drops due to engine stall (time t2). Therefore, the rotation speed Nstop is a low rotation speed. Therefore, an engine stall can be accurately determined by determining whether the rotation speed Ne of the engine 22 is equal to or lower than a predetermined rotation speed Neref.

[0030] According to the hybrid vehicle 20 equipped with the control device of the present embodiment described above, when a request to stop fuel injection of the engine 22 is made and the rotation speed Ne of the engine 22 is equal to or lower than a predetermined rotation speed Neref, it is determined that an engine stall has occurred, thereby making it possible to accurately determine whether an engine stall has occurred.

[0031] In the above-described embodiment, the determination routine illustrated in Fig. 2 is executed by the engine ECU 24. However, at least a part of the determination routine may be executed by an ECU (e.g., the HVECU 70) other than the engine ECU 24. Furthermore, this routine may be executed by an external device that can be connected to the hybrid vehicle 20 via communication.

[0032] In the embodiment described above, the control device of this embodiment is applied to a hybrid vehicle 20 of a type that includes an engine 22, a planetary gear 30, and motors MG1 and MG2. However, the control device of this embodiment may also be applied to a hybrid vehicle 20 of a type that does not include a motor MG1 or a planetary gear 30, and in which the engine 22 and the motor MG2 are connected via a clutch.

[0033] The correspondence between the main elements of the embodiment and the main elements of the invention described in the "Means for Solving the Problem" section will be described below. In the embodiment, the engine 22 corresponds to the "engine," the motor MG2 corresponds to the "motor," the hybrid vehicle 20 corresponds to the "hybrid vehicle," and the engine ECU 24 corresponds to the "controller."

[0034] The correspondence between the main elements of the embodiments and the main elements of the invention described in the "Means for Solving the Problem" section does not limit the elements of the invention described in the "Means for Solving the Problem" section, since the embodiments are examples for specifically explaining the mode for implementing the invention described in the "Means for Solving the Problem" section. In other words, the interpretation of the invention described in the "Means for Solving the Problem" section should be based on the description in that section, and the embodiments are merely specific examples of the invention described in the "Means for Solving the Problem" section.

[0035] The above describes the forms for implementing the present disclosure using embodiments, but the present disclosure is not limited to these embodiments in any way, and it goes without saying that the present disclosure can be implemented in various forms within the scope that does not deviate from the gist of the present disclosure. [Industrial Applicability]

[0036] The present disclosure is applicable to the control device manufacturing industry and the like. [Explanation of symbols]

[0037] 20 hybrid vehicle, 22 engine, 23 crankshaft, 24 engine electronic control unit (engine ECU), 28 damper, 30 planetary gear, 36 drive shaft, 38 differential gear, 39a drive wheel, 39b drive wheel, 40 motor electronic control unit (motor ECU), 41 inverter, 42 inverter, 50 battery, 52 battery electronic control unit (battery ECU), 54 power line, 80 ignition switch, 81 shift lever, 82 shift position sensor, 83 accelerator pedal, 84 accelerator pedal position sensor, 85 brake pedal, 86 brake pedal position sensor, 88 vehicle speed sensor.

Claims

1. A control device used in a hybrid vehicle that can run on power from an engine and a motor, the control device stopping the engine when a rotation speed of the engine exceeds a value of 0, Whether or not an engine stall has occurred is determined based on the engine speed when a request to stop fuel injection of the engine is made. Control device.

2. The control device according to claim 1, When the stop request is made and the engine speed is equal to or lower than a predetermined speed, it is determined that the engine stall has occurred. Control device.

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