JP4191131B2 - Control device for hybrid vehicle - Google Patents

Description

  The present invention is applied to a hybrid vehicle having an engine, a motor, and a stepped automatic transmission, and relates to a control device for a hybrid vehicle that controls the engine, the motor, and the stepped automatic transmission.

  In recent years, using an engine and a motor / generator as a power source, part of the running energy of the vehicle is converted into electric energy by the motor / generator and stored in a power storage device (so-called regenerative processing) to improve fuel efficiency. There is something. As this type of hybrid vehicle, a torque converter having a lock-up clutch is provided between a power source and a drive wheel, and the power transmission efficiency between the power source and the drive wheel is adjusted by the lock-up clutch. is there.

For example, in Patent Document 1, the charging state and temperature of a battery are detected, the charging power upper limit value is determined by referring to a table that associates the charging state and temperature of the battery with the charging power upper limit value, and instantaneous charging of the battery is performed. Techniques have been proposed in which the regenerative braking force by the motor is controlled or the braking energy is recovered in the battery so that the electric power does not exceed the charging power upper limit.
JP 2003-125502 A

However, the conventional techniques have the following problems.
That is, when the regeneration process is performed by the motor / generator, the axle and the motor / generator are connected by fastening a lock-up clutch provided in the transmission. Thereby, the kinetic energy which a vehicle body has is transmitted to a motor generator. However, the maximum capacity torque of the lockup clutch decreases when the hydraulic fluid of the transmission becomes hot. If the regenerative torque exceeds the maximum capacity torque of the lockup clutch, the lockup clutch may slip. In this case, there is a problem in that loss occurs when the kinetic energy on the vehicle side is transmitted to the motor / generator, and the regenerative energy cannot be sufficiently recovered, which may hinder improvement in fuel consumption.

  Also, if slippage occurs in the lockup clutch when the transmission fluid becomes hot and exceeds the maximum capacity torque of the lockup clutch, excessive engagement will occur at the lockup clutch engagement point (where the slippage occurred). There is a problem that the load is applied and wears, and the life of the lock-up clutch is reduced.

  Therefore, the present invention prevents slippage of the lockup clutch, sufficiently recovers regenerative energy, improves fuel consumption, and suppresses wear of the lockup clutch, regardless of the temperature state of the transmission. An object of the present invention is to provide a control device for a hybrid vehicle that can be extended.

In the invention according to claim 1, the engine and the motor / generator are connected to a transmission (for example, the multi-stage transmission 6 in the embodiment) via a lock-up clutch, and the lock-up clutch is supplied to the transmission. In a control apparatus for a hybrid vehicle configured to be operated using hydraulic oil, an oil temperature detecting means (for example, an oil temperature sensor 39 in the embodiment) for detecting an oil temperature supplied to the transmission; Based on the motor regeneration torque determining means (for example, the ECU 8 in the embodiment) that determines the motor regeneration torque from the vehicle state, and the oil temperature allowable regeneration torque that is the torque that can continue the engagement state of the lockup clutch based on the oil temperature. oil temperature allowable regenerative torque calculating means for calculating a (e.g., ECU 8 in the embodiment) and a, the oil temperature allowable regenerative DOO Click is set so as to decrease with the oil temperature becomes higher, when the oil temperature allowable regenerative torque is smaller than the motor regenerative torque, that by the oil temperature allowable regenerative torque performs regenerative control of the motor-generator Features.

  According to this invention, based on the oil temperature detected by the oil temperature detecting means, the oil temperature allowable regenerative torque calculating means calculates the oil temperature allowable regenerative torque so as not to exceed the maximum capacity torque of the lockup clutch. When the oil temperature allowable regenerative torque is smaller than the motor regenerative torque, regenerative control of the motor / generator is performed using the oil temperature allowable regenerative torque. As a result, it is possible to prevent the regenerative torque from exceeding the maximum capacity torque of the lockup clutch and causing the slippage in the lockup clutch. . Therefore, the regenerative energy can be recovered sufficiently and the fuel consumption can be improved. Further, since the occurrence of slippage due to the hydraulic oil of the lockup clutch can be prevented as described above, the occurrence of wear of the lockup clutch can be prevented, and the life of the lockup clutch can be extended.

According to a second aspect of the present invention, in the first aspect, the oil temperature detecting means detects an oil temperature of an oil pan that supplies hydraulic pressure to the transmission.
According to the present invention, the detection accuracy of the temperature of the hydraulic oil can be increased by detecting the oil temperature of the oil pan that is less affected by the flow of the hydraulic oil, and therefore more finely-tuned. Control can be achieved, further improving fuel consumption and extending the life of the lock-up clutch.

The invention according to claim 3 is the invention according to claim 1 or 2, wherein the oil temperature allowable regenerative torque calculating means sets the oil temperature at a normal temperature when the oil temperature detecting means fails. Based on this, the oil temperature allowable regenerative torque is calculated.
According to the present invention, by calculating the oil temperature allowable regenerative torque based on the oil temperature at normal temperature, it is possible to control the slip-up due to the oil temperature in the lockup clutch so that a certain amount of regenerative energy is obtained. Can be secured, and the lock-up clutch can be protected.

According to the first aspect of the present invention, regardless of the temperature state of the transmission, the lockup clutch can be prevented from slipping, the regenerative energy can be sufficiently recovered, fuel efficiency can be improved, and wear of the lockup clutch can be suppressed. Life can be extended.
According to the invention which concerns on Claim 2, finer control is attained, and the further improvement in fuel consumption and the lifetime improvement of a lockup clutch can be aimed at.
According to the invention which concerns on Claim 3, while being able to ensure a fixed amount of regenerative energy, a lockup clutch can be protected.

A hybrid vehicle control device according to an embodiment of the present invention will be described below with reference to the drawings. FIG. 1 is a block diagram showing a control apparatus for a hybrid vehicle in an embodiment of the present invention.
In this hybrid vehicle 1, an engine 2 and a motor (hereinafter referred to as “motor / generator”) 3 that can generate power are directly connected, and at least one of the power of the engine 2 and the motor / generator 3 is torque provided with a lock-up clutch 4. The power is transmitted to the output shaft 6a via the converter 5 and the multi-stage automatic transmission 6, and is transmitted from the output shaft 6a to the drive wheels W of the vehicle via a differential mechanism (not shown).

The engine 2 is a multi-cylinder reciprocating engine, and has a fuel injection / ignition control device 7 that performs fuel injection control and injection fuel ignition control for each cylinder.
In this embodiment, an electronically controlled throttle system (so-called drive-by-wire system, abbreviated as DBW system) is employed, and the operation of the throttle valve (not shown) of the engine 2 is performed by the accelerator pedal. Electronic control is performed by the ECU 8 based on the depression amount.

  The operation of the fuel injection / ignition control device 7 is controlled by the ECU 8, and automatic stop / start control (so-called idle stop control) of the engine 2 is performed under a predetermined condition. Therefore, the ECU 8 includes an accelerator pedal sensor 40 that detects the amount of depression of the accelerator pedal, a brake pedal sensor 41 that detects whether or not the brake pedal is depressed, a shift position sensor 42 that detects the shift position of the transmission 6, and an engine. From an engine speed sensor 43 for detecting the rotational speed Ne of the second rotational shaft, a transmission input shaft speed sensor 44 for detecting the vehicle speed for detecting the rotational speed Ns of the input shaft of the transmission 6, a vehicle speed sensor 45, etc. An output signal is input.

  The torque converter 5 transmits torque between the output shaft of the motor / generator 3 and the input shaft of the transmission 6 through a fluid in a state in which the lock-up clutch 4 is released. When engaged, the output shaft of the motor / generator 3 and the input shaft of the transmission 6 are substantially directly connected, and torque is transmitted directly between the output shaft and the input shaft regardless of the fluid. Done. Engagement / release of the lockup clutch 4 and shifting of the transmission 6 are performed by hydraulic control in the hydraulic control circuit 20 in accordance with the driving state of the vehicle.

When the driving force is transmitted from the driving wheel W side to the motor / generator 3 side when the hybrid vehicle 1 is decelerated, the motor / generator 3 functions as a generator to generate a so-called regenerative braking force, thereby reducing the kinetic energy of the vehicle body. It collects as electric energy and charges the battery 10 via a power drive unit (PDU) 9. The regenerative output at this time is controlled by the ECU 8 via the PDU 9.
The motor / generator 3 is driven while consuming electric energy charged in the battery 10 and is controlled by the ECU 8 via the PDU 9. A capacitor may be used instead of the battery 10.

  The hybrid vehicle 1 includes a mechanical oil pump 11 and an electric oil pump 12 having a smaller capacity than the mechanical oil pump 11 as a hydraulic pressure supply source to the hydraulic control circuit 20. The mechanical oil pump 11 is connected to the output shaft of the engine 2 and is operated by the driving force of the engine 2 or the motor / generator 3.

  On the other hand, the electric oil pump 12 is operated by an electric motor (drive motor) 13, and the pump driver 14 supplies the electric motor 13 with the electric power of the 12-volt battery 15. The electric oil pump 12 is controlled to operate when the engine 2 and the motor / generator 3 are stopped and the mechanical oil pump 11 cannot be operated.

  Next, a hydraulic circuit (hydraulic supply unit) 30 that supplies hydraulic pressure to the transmission 6 will be described with reference to FIG. The suction port 11 a of the mechanical oil pump 11 is connected to a strainer 32 disposed in the oil pan 31 by a suction pipe 33, and the discharge port 11 b of the mechanical oil pump 11 is connected to the hydraulic control circuit 20 by a discharge pipe 34. Yes. The oil pan 31 is provided with a temperature sensor 38 that detects the temperature of the hydraulic oil.

  The suction port 12 a of the electric oil pump 12 is connected to the suction pipe 33 by the suction pipe 35, and the discharge port 12 b of the electric oil pump 12 is connected to the discharge pipe 34 by the discharge pipe 36. The discharge pipe 36 is provided with a check valve 37 that permits the flow of hydraulic oil from the discharge port 12b of the electric oil pump 12 toward the discharge pipe 34 and prevents the flow of hydraulic oil from the discharge pipe 34 toward the discharge port 12b. It has been.

  As is well known, the hydraulic control circuit 20 is operated in conjunction with a shift lever in the driver's seat and is operated by a manual valve (not shown) that switches hydraulic oil supplied from the discharge pipe 34 to basic oil paths for forward, neutral and reverse. 2), a plurality of shift valves (not shown) for controlling the oil passage and hydraulic pressure of the hydraulic oil supplied from the discharge pipe 34, a plurality of solenoid valves 21 for controlling the pilot pressure of the shift valve, and the like. The operation of the clutch and brake (not shown) of the transmission 6 is controlled by controlling the oil passage and hydraulic pressure with a shift valve according to the driving state of the vehicle, and the gear position of the transmission 6 is adjusted. It enables automatic optimal control automatically.

  FIG. 3 is a flowchart showing the processing contents for determining the regenerative torque based on the oil temperature of the transmission. As shown in the figure, when the lockup clutch is engaged during deceleration, control is performed according to the following flow. First, in step S10, based on the hydraulic oil temperature of the transmission 6 detected by the oil temperature sensor 39, the oil temperature allowable regenerative torque is determined by table search. This table is shown in FIG. The oil temperature allowable regenerative torque shown in the figure is set to a torque that allows the lockup clutch 4 to remain engaged.

  In step S12, it is determined whether the oil temperature allowable regenerative torque is equal to or less than the target regenerative torque. The target regenerative torque is a regenerative torque that is calculated depending on the state of the vehicle such as the gear position (GP) of the transmission 6, the number of revolutions of the engine 2, whether or not the brake is operated, the remaining capacity of the battery 10, and whether or not the air conditioner is operating. is there. If this determination is YES, the process proceeds to step S14. In step S14, the oil temperature allowable regenerative torque is substituted for the target regenerative torque, and the process of this flowchart is terminated. Moreover, when the determination result of step S12 is NO, the process of this flowchart is complete | finished as it is, without changing target regeneration torque.

As a result, it is possible to prevent the regenerative torque from exceeding the maximum capacity torque of the lock-up clutch 4 and causing the slip-up in the lock-up clutch 4, so that loss occurs when the vehicle-side kinetic energy is transmitted to the motor / generator 3. Can be prevented. Therefore, the regenerative energy can be recovered sufficiently and the fuel consumption can be improved.
Moreover, since the occurrence of slippage due to the hydraulic oil of the lockup clutch 4 can be prevented as described above, the occurrence of wear of the lockup clutch 4 can be prevented and the life of the lockup clutch 4 can be extended.

  Further, by providing the oil temperature sensor 39 in the oil pan 31 that is less affected by the flow of the hydraulic oil and detecting the oil temperature, the detection accuracy of the temperature of the hydraulic oil can be increased. Therefore, finer control is possible, and further improvement in fuel consumption and longer life of the lockup clutch 4 can be achieved.

  Of course, the contents of the present invention are not limited to the above-described embodiments. For example, the transmission may be a continuously variable transmission as well as a multi-stage (stepped) transmission. Further, if the oil temperature allowable regeneration torque is calculated based on the oil temperature at the normal temperature when the oil temperature sensor 39 fails, the lockup clutch 4 is controlled so as not to slip due to the oil temperature. Can do. This is preferable in that a certain amount of regenerative energy can be secured and the lock-up clutch can be protected, but the present invention can also be applied when such control is not performed. In addition, if the oil temperature allowable regenerative torque is set to the same value as the maximum capacity torque of the lockup clutch, it is preferable in that the maximum regenerative energy can be stored while preventing the lockup clutch from slipping. Any value that does not exceed the capacity torque may be used.

It is a block diagram which shows the control apparatus of the hybrid vehicle in embodiment of this invention. A hydraulic circuit for supplying hydraulic pressure to the transmission will be described. It is a flowchart which shows the processing content which performs the regeneration torque determination based on the oil temperature of a transmission. It is a figure which shows the table of oil temperature allowable regeneration torque and oil temperature.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 ... Hybrid vehicle 2 ... Engine 3 ... Motor generator 4 ... Lock-up clutch 6 ... Multistage automatic transmission (transmission)
8 ... ECU (motor regeneration torque determining means, oil temperature allowable regeneration torque calculating means)
31 ... Oil pan 39 ... Oil temperature sensor (oil temperature detecting means)

Claims (3)

In the hybrid vehicle control apparatus, wherein the engine and the motor / generator are connected to the transmission via a lock-up clutch, and the lock-up clutch is operated using hydraulic oil supplied to the transmission.
Oil temperature detecting means for detecting the oil temperature supplied to the transmission;
Motor regeneration torque determining means for determining the motor regeneration torque from the vehicle state;
Oil temperature allowable regenerative torque calculating means for calculating an oil temperature allowable regenerative torque that is a torque capable of continuing the engagement state of the lockup clutch based on the oil temperature;
The oil temperature allowable regenerative torque is set to decrease as the oil temperature increases,
When the oil temperature allowable regenerative torque is smaller than the motor regenerative torque, regenerative control of the motor / generator is performed by the oil temperature allowable regenerative torque. 2. The control apparatus for a hybrid vehicle according to claim 1, wherein the oil temperature detecting means detects an oil temperature of an oil pan that supplies hydraulic pressure to the transmission. The oil temperature allowable regenerative torque calculating means calculates the oil temperature allowable regenerative torque based on an oil temperature at a normal temperature when the oil temperature detecting means fails. The control apparatus of the hybrid vehicle described in 2.

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