JP7708025B2 - Hybrid vehicle control device - Google Patents

Description

The present invention relates to a control device for a hybrid vehicle.

Conventionally, as a control device for this type of hybrid vehicle, one has been proposed that controls the engine and the first and second motors of a hybrid vehicle that includes a multiple cylinder engine, an exhaust gas purification device with a catalyst that purifies exhaust gas from the engine, and first and second motors (see, for example, Patent Document 1). In this device, during execution of partial cylinder fuel cut (partial cylinder FC) control that stops the supply of fuel to at least one of the multiple cylinders, the engine speed is increased compared to when partial cylinder FC control is not being executed. This suppresses deterioration of drivability during partial cylinder FC control.

JP 2021-127709 A

In the hybrid vehicle control device described above, when partial cylinder FC control is being performed, the engine speed is increased compared to when partial cylinder FC control is not being performed, regardless of the driving state of the hybrid vehicle, which can cause the driver to feel uncomfortable depending on the driving state of the hybrid vehicle.

The hybrid vehicle control device of the present invention aims to prevent the driver from feeling uncomfortable when partial cylinder fuel cut control is being performed.

The hybrid vehicle control device of the present invention employs the following means to achieve the above-mentioned main objective.

The control device for a hybrid vehicle of the present invention comprises:
A control device for a hybrid vehicle includes a multiple cylinder engine, an exhaust gas purification device having a catalyst for purifying exhaust gas from the engine, a first motor, a planetary gear having three rotating elements connected to three shafts including the engine, the first motor, and a drive shaft connected to drive wheels, and a second motor connected to the drive shaft, the control device controlling the engine and the first and second motors,
executing a partial cylinder fuel cut control to stop fuel supply to at least one of the plurality of cylinders;
The gist of the invention is that while the partial cylinder fuel cut control is being executed, the engine speed is increased based on the driving state of the hybrid vehicle compared to when the partial cylinder fuel cut control is not being executed under the same driving state.

1 is a diagram showing an outline of the configuration of a hybrid vehicle 20. FIG. 4 is a flowchart showing an example of a control routine. FIG. 2 is an explanatory diagram showing an example of a shift line map.

Next, we will explain how to implement the present invention using examples.

1 is a schematic diagram showing the configuration of a hybrid vehicle 20 equipped with a control device according to an embodiment of the present invention. As shown in the figure, the hybrid vehicle 20 includes an engine 22, an exhaust gas purification device (purification device) 24, a planetary gear 30, motors MG1 and MG2 (first and second motors), inverters 41 and 42, a battery 50, a transmission (transmission device) 60, and an electronic control unit (hereinafter referred to as "ECU") 70. The engine 22 is configured as an internal combustion engine, and is controlled by the ECU 70. The exhaust gas purification device 24 includes a catalyst that purifies exhaust gas containing carbon monoxide (CO) and hydrocarbons (HC) and an oxygen storage catalyst that stores oxygen in the exhaust gas. The planetary gear 30 is configured as a single-pinion type planetary gear mechanism, with a rotor of the motor MG1 connected to the sun gear, an input shaft 33 of the transmission 60 connected to the ring gear, and a crankshaft 23 of the engine 22 connected to the carrier. The motors MG1 and MG2 are configured as, for example, synchronous generator motors, with the motor MG2 connected to the input shaft 33. The inverters 41 and 42 are used to drive the motors MG1 and MG2 and are connected to a battery 50 via a power line 54. The motors MG1 and MG2 are rotationally driven by the ECU 70 controlling the switching of a plurality of switching elements (not shown) of the inverters 41 and 42. The battery 50 is configured as a secondary battery and is managed by the ECU 70. The transmission 60 is configured as a stepped transmission with, for example, 10 speeds, and is connected to the input shaft 33 and the drive shaft 36 connected to the drive wheels 39a, 39b via a differential gear 38, and is controlled by an ECU 70. The ECU 70 includes a microcomputer having a CPU, ROM, RAM, flash memory, input/output ports, and communication ports (not shown). Signals from various sensors are input to the ECU 70 via the input ports. Examples of signals input to the ECU 70 include signals from various sensors necessary for controlling the operation of the engine 22, rotational positions θm1, θm2 from rotational position sensors (not shown) that detect the rotational positions of the rotors of the motors MG1, MG2, detection values from sensors that detect the running state of the vehicle (for example, accelerator opening Acc from a sensor that detects the opening of the accelerator pedal and vehicle speed V from a vehicle speed sensor that detects the vehicle speed), and other signals from various sensors necessary for controlling the operation of the motors MG1, MG2, signals from various sensors necessary for managing the battery 50, and switch signals from a switch SW that is turned on when there is a request for partial cylinder fuel cut (partial cylinder FC) control (partial cylinder FC request) described later. From the ECU 70, various control signals for controlling the operation of the engine 22, switching control signals to multiple switching elements (not shown) of the inverters 41, 42, and shift control signals to the transmission 60 are output via the output port.

In the hybrid vehicle 20 of the embodiment thus configured, the vehicle runs in a hybrid driving (HV driving) mode in which the engine 22 is operated, or in an electric driving (EV driving) mode in which the engine 22 is stopped, under the control of the ECU 70. For example, in the HV driving mode, the ECU 70 basically executes a first control that controls the drive of the engine 22 and the motors MG1, MG2 so that the engine 22 is efficiently operated at a speed equal to or higher than the lower limit speed Nemin. In the first control, the lower limit speed Nemin is set to a predetermined speed as the lower limit of the speed at which the engine 22 does not misfire. In controlling the transmission 60, the ECU 70 sets a target gear M* of the transmission 60 based on the accelerator opening Acc, the vehicle speed V, and the shift diagram, and when the current gear M of the transmission 60 matches the target gear M*, the ECU 70 controls the transmission 60 so that the gear M is maintained, and when the gear M and the target gear M* differ, the ECU 70 executes shift control (upshift or downshift) to control the transmission 60 so that the gear M matches the target gear M*. The shift diagram will be described later. When a request to increase the temperature of the exhaust gas purification device 24 is made during the load operation of the engine 22, the ECU 70 displays the request on a display (not shown) near the driver's seat. When the switch SW is turned on, the ECU 70 executes a partial cylinder fuel cut (partial cylinder FC) control to stop the fuel supply to at least one of the multiple cylinders. By implementing this partial cylinder FC control, more air is supplied to the exhaust gas purification device 24 in a low-temperature environment, causing the temperature to rise.

Next, the operation of the hybrid vehicle 20 thus configured, particularly the operation while the vehicle is traveling in HV driving mode, will be described. FIG. 2 is a flowchart showing an example of a control routine executed by the ECU 70. This routine is executed at predetermined time intervals (e.g., every few msec) while the vehicle is traveling in HV driving mode and the engine 22 is operating under load.

When this routine is executed, the ECU 70 determines whether the switch SW is on or not, i.e., whether there is a request for partial cylinder FC (step S100). When the switch SW is off, the ECU 70 determines that there is no request for partial cylinder FC and executes normal control (step S110), and when the switch SW is on, it determines that there is a request for partial cylinder FC and executes partial cylinder FC control (step S120), and ends this routine. In the normal control of step S110, the engine 22 and motors MG1 and MG2 are subjected to the first control described above, and the transmission 60 is controlled using the solid and dashed shift lines in the shift line diagram shown in FIG. 3.

In the partial cylinder FC control of step S120, the transmission 60 is controlled using the dashed and dotted shift lines in the shift diagram shown in FIG. 3. The dashed and dotted shift lines are set so that a lower gear can be selected at the same vehicle speed V and accelerator opening Acc than the solid and dashed shift lines. Note that FIG. 3 only shows the shift lines for 1st to 4th gears, but the shift lines for 5th to 10th gears are also set so that a lower gear can be selected at the same vehicle speed V and accelerator opening Acc than the solid and dashed shift lines.

In the control during partial cylinder FC in step S120, the second control is executed for the engine 22 and the motors MG1 and MG2 instead of the first control. In the second control, first, the temporary target rotation speed Netmp of the engine 22 is set using the vehicle speed V, the target gear M*, and the second control rotation speed setting map. In the second control rotation speed setting map, the temporary target rotation speed Netmp is set so that it increases linearly as the vehicle speed V increases at each gear, and the slope with respect to the vehicle speed V decreases as the gear increases. As a result, when the engine 22 is operated at the temporary target rotation speed Netmp, the rotation speed Ne of the engine 22 increases as the vehicle speed V increases at each gear of the transmission 60, and when the gear is upshifted, the rotation speed Ne of the engine 22 decreases, and when the gear is downshifted, the rotation speed Ne of the engine 22 increases. This allows the behavior of the engine speed Ne of the engine 22 to be closer to the behavior of an engine mounted on an automobile equipped with an engine and a stepped transmission, thereby suppressing the driver's discomfort. By setting the temporary target speed Netmp in this manner, the temporary target speed Netmp becomes higher than when the solid and dashed lines in the shift diagram shown in Figure 3 are used. As a result, when the engine 22 is operated at the temporary target speed Netmp, there are more opportunities to make the period of torque fluctuation of the engine 22 higher than the resonance frequency band of the drivetrain, thereby suppressing vehicle vibration and suppressing the driver's discomfort. When the ECU 70 sets the tentative target speed Netmp of the engine 22, it sets the lower limit speed Nemin of the engine 22 higher than that in the first control, and higher when the accelerator opening Acc is high compared to when it is low, and higher when the vehicle speed V is high compared to when it is low. It sets the larger of the tentative target speed Netmp and the lower limit speed Nemin as the target speed Ne* of the engine 22, sets a target power Pe* of the engine 22 so that the vehicle runs with running power based on the accelerator opening Acc and the vehicle speed V, and drives and controls the engine 22 and the motors MG1, MG2 so that the engine 22 is operated with a target torque Te* obtained by dividing the target power Pe* by the target speed Ne* and the target speed Ne*, and runs with a running torque Td*. In this way, by setting the lower limit rotation speed Nemin higher when the accelerator opening Acc is high compared to when it is low, and higher when the vehicle speed V is high compared to when it is low, the behavior of the rotation speed Ne of the engine 22 can be made closer to the behavior of an engine installed in an automobile equipped with an engine and a stepped transmission, and discomfort felt by the driver can be suppressed.

According to the hybrid vehicle 20 equipped with the control device of the embodiment described above, partial cylinder FC control is executed to stop fuel supply to at least one of the multiple cylinders, and during execution of partial cylinder FC control, the accelerator opening Acc, vehicle speed V, and the dashed dotted shift line of the shift diagram shown in FIG. 3 are used to increase the engine 22 speed Ne compared to the first control in which partial cylinder FC control is not executed at the same accelerator opening Acc and vehicle speed V, thereby suppressing the driver from feeling uncomfortable during execution of partial cylinder FC control.

In the hybrid vehicle 20 equipped with the control device of the embodiment, in the second control during partial cylinder FC control, the engine 22 rotation speed Ne is made higher than when the first control is executed at the same accelerator opening Acc and vehicle speed V by using the dashed-dotted shift line in the shift diagram shown in FIG. 3 or by making the lower limit rotation speed Nemin higher. In addition to using the dashed-dotted shift line and the lower limit rotation speed Nemin in the shift diagram shown in FIG. 3, or by replacing at least one of the dashed-dotted shift line and the lower limit rotation speed Nemin in the shift diagram shown in FIG. 3, the engine 22 rotation speed Ne may be made higher than when the first control is executed at the same accelerator opening Acc and vehicle speed V by increasing the slope of the tentative target rotation speed Netmp with respect to the vehicle speed V in the second control rotation speed setting map or by prohibiting shifting to a higher gear for each vehicle speed.

The above describes the form for carrying out the present invention using examples, but the present invention is not limited to these examples in any way, and it goes without saying that the present invention can be carried out in various forms without departing from the scope of the invention.

The present invention can be used in the hybrid vehicle manufacturing industry, etc.

20 hybrid vehicles, 70 electronic control units (ECUs).

Claims (1)

A hybrid vehicle control device includes an engine having multiple cylinders, an exhaust gas purification device having a catalyst for purifying exhaust gas from the engine, a first motor, a planetary gear having three rotating elements connected to three shafts, the engine, the first motor, and an input shaft , a second motor connected to the input shaft, and a stepped transmission connected to the input shaft and a drive shaft connected to drive wheels, the hybrid vehicle control device controlling the engine, the first and second motors, and the stepped transmission ,
executing a partial cylinder fuel cut control to stop fuel supply to at least one of the plurality of cylinders;
When the partial cylinder fuel cut control is being executed, the stepped transmission is controlled to be in a lower gear than when the partial cylinder fuel cut control is not being executed at the same vehicle speed and accelerator opening, the engine and the first and second motors are set to a provisional target rotation speed that increases linearly as the vehicle speed increases and that the gradient with respect to the vehicle speed decreases as the gear stage of the stepped transmission increases, a lower limit rotation speed is set that is higher than a lower limit value of the rotation speed at which the engine does not misfire and is higher when the accelerator opening is high compared to when it is low and is higher when the vehicle speed is high compared to when it is low, the larger of the provisional target rotation speed and the lower limit rotation speed is set to a target rotation speed for the engine, a target power for the engine is set so that the hybrid vehicle runs with a running power based on the accelerator opening and the vehicle speed, and the engine is controlled so that the engine is operated at a target torque obtained by dividing the target power by the target rotation speed and the target rotation speed, and the hybrid vehicle runs with a running torque.
Hybrid vehicle control device.