JP2022075046A - Control device of hybrid vehicle - Google Patents

Abstract

To provide a control device of a hybrid vehicle which can drive a mechanical oil pump provided on an input shaft of a transmission mechanism in the neutral state and suppress sudden change of the driving force in the failure.SOLUTION: A control device of a hybrid vehicle is configured such that a transmission mechanism is turned into the neutral state when setting a series travel model, and a transmission torque capacity of a friction clutch is set to be a torque capacity that is determined so that torque transmitted to an input shaft via the friction clutch becomes equal to or greater than torque that can drive a mechanical oil pump and the torque transmitted to drive wheels becomes equal to or less than prescribed torque when the transmission mechanism transmits the torque (step S3).SELECTED DRAWING: Figure 2

Description

The present invention is a series of running in a parallel running mode in which the engine and the motor are powered to run, and a series in which the engine power is converted into electric power by a generator and the converted power is output from the motor to which the power is supplied. It relates to a control device for a hybrid vehicle that can set a driving mode.

Patent Document 1 describes a parallel traveling mode in which the engine is transmitted by transmitting the output torque of the engine to the rear wheels and the output torque of the motor is transmitted to the front wheels, and the power of the engine is converted into electric power by a generator and the conversion thereof. A control device for a hybrid vehicle that can be set to a series driving mode in which the motor is driven by supplying the generated electric power to the motor is described. A generator is connected to the output shaft of this engine, and a transmission mechanism capable of setting a plurality of shift stages including neutral is connected to the downstream side of the generator via a clutch mechanism. Then, when the series running mode is set, this control device releases the clutch mechanism and sets the speed change mechanism to neutral in order to reduce the drag torque of the rotating member constituting the speed change mechanism. It is configured in. When there is a high possibility of shifting from the series driving mode to the parallel driving mode, such as when the vehicle speed is high or when the required driving force is large, the speed change mechanism changes to a predetermined speed while maintaining the clutch mechanism released. It is configured to set the stage.

In Patent Document 2, similarly to the hybrid vehicle described in Patent Document 1, the output torque of the engine is transmitted to the rear wheels via the generator, the clutch mechanism, and the transmission mechanism, and the output torque of the motor is transmitted to the front wheels. A hybrid vehicle configured to be transmitted to is described. The hybrid vehicle described in Patent Document 2 further includes a first case for accommodating a speed change mechanism and a second case for accommodating a motor and a deceleration mechanism capable of increasing the output torque of the motor. By providing an electric oil pump inside the first case, oil can be supplied to the first case and the second case and the hydraulic pressure of the clutch mechanism can be supplied during EV running that runs only with the power of the motor. It is configured to be able to generate. A mechanical oil pump is connected to the engine via a transmission member such as a chain or a belt, and oil can be supplied from the mechanical oil pump into the first case or the second case when the engine is driven. It is configured as follows.

Patent Document 3 describes a hybrid vehicle in which each device is arranged in the order of an engine, a clutch mechanism, a motor, and a speed change mechanism. In addition, this hybrid vehicle is equipped with a mechanical oil pump driven by the power of the engine and motor on the input shaft of the transmission mechanism, and the engine and motor are stopped, and the hydraulic pressure is increased while the vehicle is stopped. Is provided with an electric oil pump that can generate.

Japanese Unexamined Patent Publication No. 2019-142365 Japanese Unexamined Patent Publication No. 2019-123387 Japanese Unexamined Patent Publication No. 2013-06313

In the hybrid vehicle described in Patent Document 1, in order to reduce the resistance force during traveling in the series traveling mode, the clutch mechanism is released and the shifting mechanism is set to neutral. By setting the clutch mechanism and the speed change mechanism in a state in which torque is cut off in this way, even if one of them is unintentionally engaged, the other is in a state in which torque transmission is cut off. As a result, it functions as a so-called fail-safe and can suppress sudden changes in the driving force.

On the other hand, a mechanical oil pump for discharging oil for lubricating or cooling the speed change mechanism or for cooling a motor or a generator may be provided on the input shaft of the speed change mechanism. In order to drive the mechanical oil pump provided on the input shaft during driving in the series driving mode, the clutch mechanism is engaged to transmit torque from the engine to the mechanical oil pump, or the transmission mechanism is operated. The torque is set so that the torque can be transmitted, and the torque is transmitted from the drive wheels to the mechanical oil pump. Therefore, if the clutch mechanism or transmission mechanism that blocks the transmission of torque is unintentionally engaged, the driving engine and the drive wheels are connected so that torque can be transmitted, and the driving force may change suddenly. There is. That is, there is room for technical improvement in order to both drive the mechanical oil pump provided on the input shaft and suppress sudden changes in the driving force at the time of failure.

The present invention has been made by paying attention to the above technical problems, and suppresses sudden changes in the driving force at the time of fail while driving the mechanical oil pump provided on the input shaft of the transmission mechanism in the neutral state. It is an object of the present invention to provide a control device for a hybrid vehicle capable of achieving both.

In order to achieve the above object, the present invention comprises an engine, a generator connected to the output shaft of the engine to convert the power of the engine into electric power, and a torque capacity for transmitting the output torque of the engine to the drive wheels. A friction clutch that can be changed, a torque transmission state in which torque is transmitted from the engine via the friction clutch, and the magnitude of the transmitted torque is changed to be output to the drive wheels, and transmission of the torque. A speed change mechanism that can selectively set the neutral state in which the engine is cut off, a mechanical oil pump that is driven by transmitting power from the input shaft of the speed change mechanism, and a torque transferable connection to the drive wheel or another drive wheel. It also includes a motor that can be driven by being supplied with the power generated by the generator, and the engine transmits torque to the drive wheels, and the motor transmits torque to the drive wheels or other drive wheels. The parallel travel mode in which the engine travels and the transmission of torque between the engine and the drive wheels are cut off, the power of the engine is converted into electric power by the generator, and the converted power is supplied to the motor. In a control device for a hybrid vehicle configured to be able to set at least two driving modes with a series driving mode, the friction clutch and a controller for controlling the speed change mechanism are provided, and the controller is the controller. When the series running mode is set, the speed change mechanism is set to the neutral state, the transmission torque capacity of the friction clutch is set, and the torque transmitted to the input shaft via the friction clutch is the mechanical oil pump. The torque capacity is set so that the torque transmitted from the engine to the drive wheels is equal to or less than a predetermined torque when the torque is equal to or higher than the torque that can be driven and the transmission mechanism transmits the torque. It is characterized by being done.

According to the present invention, the series running mode can be set by setting the speed change mechanism to the neutral state and blocking the transmission of torque between the engine and the drive wheels. In addition, by setting the transmission torque capacity of the friction clutch to be greater than the torque that can drive the mechanical oil pump, power can be transmitted from the engine to the mechanical oil pump via the friction clutch, resulting in series running. The mechanical oil pump can be driven while maintaining the mode. Therefore, since oil can be supplied from the mechanical oil pump to other devices such as a motor, the traveling period in the series traveling mode can be extended. Furthermore, even when the speed change mechanism is switched to the torque transmission state due to a failure of the actuator that controls the speed change mechanism, the friction clutch functions as a torque fuse, so that excessive torque is transmitted from the engine to the drive wheels. It can be suppressed. That is, it is possible to prevent the driver from feeling uncomfortable due to a sudden change in the driving force.

It is a schematic diagram for demonstrating an example of the hybrid vehicle in embodiment of this invention. It is a flowchart for demonstrating an example which controls a rear shift mechanism and a friction clutch according to a set driving mode.

An example of the hybrid vehicle Ve in the embodiment of the present invention will be described with reference to FIG. The vehicle Ve shown in FIG. 1 drives the rear wheels 3 by the power of the engine (Eng) 1 and the rear motor (Rr-MG) 2, and drives the front wheels 5 by the power of the front motor (Fr-MG) 4. It is a four-wheel drive hybrid vehicle configured in. Instead of the front motor 4, another motor capable of transmitting torque to the rear wheels 3 may be provided.

The engine 1 can adopt various engines such as a conventionally known gasoline engine and a diesel engine, and is configured to be able to control the output torque by controlling the intake air amount, the fuel injection amount, and the like. There is.

The rear motor 2 and the front motor 4 can be configured in the same manner as a motor provided as a driving force source for a conventionally known electric vehicle or hybrid vehicle, and output driving torque according to the energized power. In addition, it has a function as a generator that converts a part of the power of the rotating shaft into electric power by outputting torque so as to reduce the number of rotations. These motors 2 and 4 can be configured by, for example, a permanent magnet type synchronous motor having a permanent magnet in the rotor. The rear motor 2 corresponds to the "generator" in the embodiment of the present invention, and the front motor 4 corresponds to the "motor" in the embodiment of the present invention.

A rear motor 2 is connected to the output shaft 6 of the engine 1, and a rear speed change mechanism (Rr-T / M) 9 is connected to the output shaft 7 via a friction clutch 8. The friction clutch 8 is configured to be able to control the torque capacity transmitted by a hydraulic actuator or an electromagnetic actuator. That is, the friction clutch 8 disconnects the engaged state in which the output shaft 7 of the rear motor 2 and the input shaft 10 of the rear speed change mechanism 9 are connected, and the output shaft 7 of the rear motor 2 and the input shaft 10 of the rear speed change mechanism 9. The released state and the slip state in which the rotating shafts 7 and 10 can rotate relative to each other while transmitting a predetermined torque between the output shaft 7 of the rear motor 2 and the input shaft 10 of the rear transmission mechanism 9 are set. It is configured to be able to.

Further, the rear shift mechanism 9 shown here is a stepped shift mechanism capable of setting a neutral state and a plurality of shift stages. That is, when any of the gears is set, the magnitude of the torque transmitted from the engine 1 via the friction clutch 8 is changed to the magnitude corresponding to the gear ratio of the gear, and the rear wheels 3 are changed. It is configured to output to. The rear shift mechanism 9 is provided with a plurality of clutch mechanisms (not shown) for setting each shift stage. The clutch mechanism provided in the rear speed change mechanism 9 can adopt a friction type clutch mechanism or a meshing type clutch mechanism, and releases all of these clutch mechanisms or at least one of the selected clutch mechanisms. By doing so, the rear speed change mechanism 9 is configured to be in the neutral state. In the following description, an example in which a meshing type clutch mechanism (hereinafter referred to as a dog clutch) is adopted as the clutch mechanism provided in the rear speed change mechanism 9 will be described. A pair of rear wheels 3 are connected to the output shaft 11 of the rear transmission mechanism 9 via the rear differential gear unit 12. The state in which the rear speed change mechanism 9 sets one of the shift stages and transmits torque corresponds to the "torque transmission state" in the embodiment of the present invention.

Further, the input shaft 10 of the rear speed change mechanism 9 is provided with a mechanical oil pump 13 driven by the power of the input shaft 10. The mechanical oil pump 13 pumps oil for lubrication and cooling of the rotating members constituting the rear transmission mechanism 9 and the front transmission mechanism 14 described later, or cooling of the motors 2 and 4 from an oil pan (not shown). The oil is discharged, and the oil is supplied to the rear speed change mechanism 9, the front speed change mechanism 14, which will be described later, or the rear motor 2 and the front motor 4 via an oil passage (not shown).

A front speed change mechanism 14 for changing the operating point of the front motor 4 is connected to the front motor 4 described above. The front transmission mechanism 14 has a stepped transmission mechanism capable of setting two transmission stages, a directly connected stage having a gear ratio of "1" and a reduction gear having a gear ratio larger than "1". Adopt various speed change mechanisms such as a stepped speed change mechanism that can set three or more speed change stages (including speed increase stages) or a stepless speed change mechanism that can continuously change the gear ratio. Can be done. A pair of front wheels 5 are connected to the output shaft 15 of the front transmission mechanism 14 via the front differential gear unit 16.

It is provided with an electronic control device (hereinafter referred to as an ECU) 17 for controlling the engine 1, the motors 2 and 4, the transmission mechanisms 9 and 14, and the friction clutch 8 described above. The ECU 17 corresponds to the "controller" in the embodiment of the present invention, and is mainly composed of a microcomputer and is stored in advance with input data, like a conventionally known electronic control device. Calculations are performed based on data and the like, and signals corresponding to the calculation results are output to the engine 1, the motors 2 and 4, the transmission mechanisms 9 and 14, and the friction clutch 8.

The ECU 17 has, for example, a sensor for detecting the operation amount of the accelerator pedal, a sensor for detecting the vehicle speed, a sensor for detecting the engine rotation speed, a sensor for detecting the rotation speed of each of the motors 2 and 4, and an input rotation of the rear speed change mechanism 9. A sensor for detecting the number, a sensor for detecting the temperature of each of the motors 2 and 4, and the like are electrically connected.

Further, the ECU 17 has, for example, a map for determining the fuel injection amount and the intake air amount to the engine 1 based on the operation amount of the accelerator pedal and the vehicle speed, and for determining the electric power to be energized to the motors 2 and 4. A map or a map for determining the shift stage (gear ratio) of each of the shift mechanisms 9 and 14 is stored.

The hybrid vehicle Ve configured as described above has a parallel traveling mode in which the power of the engine 1 is transmitted to the rear wheels 3 and the power of the front motor 4 is transmitted to the front wheels 5 to travel, and the power of the engine 1 is transmitted to the rear motor. A series driving mode in which the vehicle is converted into electric power by 2, supplies the converted electric power or the electric power charged in a battery (not shown) to the front motor 4, and transmits the power of the front motor 4 to the front wheels 5. At least two driving modes can be set.

FIG. 2 shows a flowchart for explaining an example of controlling the rear speed change mechanism 9 and the friction clutch 8 according to the set traveling mode. In the control example shown in FIG. 2, first, in order to determine the current traveling mode, it is determined whether or not the traveling mode is the parallel traveling mode (step S1). This step S1 can be determined based on the traveling region with the required driving force and the vehicle speed as parameters, the temperature limiting conditions of the motors 2 and 4, and the like.

If it is positively determined in step S1 due to the parallel traveling mode, it is determined based on the required driving force, the vehicle speed, and the map for determining the shift stage of the rear transmission mechanism 9 stored in the ECU 17. The dog clutch for setting the shift stage is engaged, and the friction clutch 8 is set in the engaged state (step S2), and this routine is temporarily terminated. That is, the friction clutch 8 and the rear speed change mechanism 9 are set in a state in which torque can be transmitted so that the output torque of the engine 1 can be transmitted to the rear wheels 3.

On the contrary, when it is negatively determined in step S2 because it is not in the parallel traveling mode, that is, when the series traveling mode is set, the rear transmission mechanism 9 is set to the neutral state and the friction clutch 8 is transmitted. The torque capacity is set to a predetermined torque (step S3), and this routine is temporarily terminated.

The predetermined torque in step S3 is determined so that the torque transmitted from the engine 1 to the input shaft 10 via the friction clutch 8 is equal to or greater than the torque that can drive the mechanical oil pump 13. Specifically, when the rear transmission mechanism 9 is in the neutral state, the inertia torque and friction torque of the member that rotates integrally with the input shaft 10 and the load torque for driving the mechanical oil pump 13 are added up. Set the predetermined torque so that it exceeds the torque. That is, the predetermined torque is determined with the torque that can drive the mechanical oil pump 13 as the lower limit value.

Further, when the rear transmission mechanism 9 unintentionally switches to a state in which torque can be transmitted and torque is transmitted from the engine 1 to the rear wheels 3, the change in the driving force based on the transmitted torque is the operation. The predetermined torque is set so that the change does not make the person feel uncomfortable. That is, a predetermined torque is set so that the friction clutch 8 functions as a torque fuse. In other words, the torque value required to function as a torque fuse is set as the upper limit value of the predetermined torque. It is preferable to set an upper limit value of a predetermined torque so that the dog clutch can function as a torque fuse when the dog clutch for setting the shift stage having the smallest gear ratio that can be set by the rear transmission mechanism 9 is engaged.

Further, when the transmission torque capacity of the friction clutch 8 is sharply reduced when switching from the parallel running mode to the series running mode, the running load is lowered and the engine speed is sharply increased. Therefore, the control device according to the embodiment of the present invention is configured to reduce the transmission torque capacity of the friction clutch 8 at a rate of change that does not cause a sudden change in the engine speed when switching from the parallel traveling mode to the series traveling mode. Has been done. It should be noted that the rate of change in the engine speed that the driver feels uncomfortable is obtained in advance by experiments or the like, and friction is obtained based on the obtained rate of change in the engine speed, the inner clutch of the engine 1, and the output torque of the engine 1. The rate of change in the transmission torque capacity of the clutch 8 can be determined.

As described above, the series traveling mode can be set by setting the rear speed change mechanism 9 to the neutral state and blocking the transmission of torque between the engine 1 and the rear wheels 3. Further, by setting the transmission torque capacity of the friction clutch 8 to a transmission torque capacity sufficient to drive the mechanical oil pump 13, power is transmitted from the engine 1 to the mechanical oil pump 13 via the friction clutch 8. As a result, the mechanical oil pump 13 can be driven while maintaining the series running mode. Therefore, since oil can be supplied from the mechanical oil pump 13 to the front transmission mechanism 14 and the motors 2 and 4, the traveling period in the series traveling mode can be lengthened.

Further, even when any of the shift stages of the rear shift mechanism 9 is set due to a failure of the actuator that controls the rear shift mechanism 9, the friction clutch 8 functions as a torque fuse, so that the engine 1 is rearward. It is possible to suppress the transmission of excessive torque to the wheel 3. That is, it is possible to prevent the driver from feeling uncomfortable due to a sudden change in the driving force.

The control device according to the embodiment of the present invention is not limited to the one in which the transmission torque capacity of the friction clutch 8 is always set to the predetermined torque described above while the series traveling mode is set, and the motors 2 and 4 and the like. If there is no request to supply oil to the front speed change mechanism 14, the friction clutch 8 may be released.

1 Engine 2 Rear motor 3 Rear wheel 4 Front motor 5 Front wheel 8 Friction clutch 9 Rear speed change mechanism 10 Input shaft 13 Mechanical oil pump 14 Front speed change mechanism 17 Electronic control device (ECU)
Ve vehicle

Claims (1)

Through the engine, a generator connected to the output shaft of the engine and converting the power of the engine into electric power, a friction clutch capable of changing the torque capacity for transmitting the output torque of the engine to the drive wheels, and the friction clutch. A speed change that can selectively set a torque transmission state in which torque is transmitted from the engine and the magnitude of the transmitted torque is changed to be output to the drive wheels and a neutral state in which the transmission of the torque is cut off. The mechanism, the mechanical oil pump driven by transmitting power from the input shaft of the speed change mechanism, and the power that is connected to the drive wheels or other drive wheels so that torque can be transmitted and generated by the generator are supplied. Equipped with a motor that can be driven
A parallel travel mode in which torque is transmitted from the engine to the drive wheels and torque is transmitted from the motor to the drive wheels or the other drive wheels to travel, and torque transmission between the engine and the drive wheels is performed. At least two driving modes, that is, a series driving mode in which the power of the engine is converted into electric power by the generator and the converted electric power is supplied to the motor to drive the motor, can be set. In the control device of the configured hybrid vehicle
A controller for controlling the friction clutch and the speed change mechanism is provided.
The controller
When the series running mode is set, the speed change mechanism is set to the neutral state, and the transmission torque capacity of the friction clutch and the torque transmitted to the input shaft via the friction clutch are the mechanical oil pump. The torque capacity is set so that the torque transmitted from the engine to the drive wheels is equal to or less than a predetermined torque when the torque is equal to or higher than the torque capable of driving the clutch and the transmission mechanism transmits the torque. A control device for a hybrid vehicle, characterized in that it is configured.

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