JP5565556B2 - Control device for hybrid electric vehicle - Google Patents

Description

  The present invention relates to a control device for a hybrid electric vehicle including an engine and an electric motor.

  In recent years, an engine and an electric motor that can generate electricity are connected to a power transmission mechanism that is connected to a drive wheel of a vehicle, and drive assistance is performed by the motor as necessary when the vehicle is traveling, and power input from the drive wheel during deceleration A hybrid electric vehicle has been developed in which the electric power is transmitted to the electric motor, the regenerative operation is performed by the electric motor, the deceleration energy is converted into the regenerative energy, and the power storage device is charged as electric energy.

  When such a hybrid electric vehicle employs a hydraulically operated automatic transmission, the operating oil pressure of the transmission mechanism in the automatic transmission is ensured by a mechanical oil pump driven by an engine. If the engine is stopped when the vehicle is stopped, the mechanical oil pump is also stopped along with this, so that the hydraulic pressure of the transmission mechanism cannot be ensured.

  Therefore, a hydraulic control device for an automatic engine stop vehicle having an electric oil pump separately from a mechanical oil pump driven by the engine is disclosed so that the hydraulic pressure of the transmission mechanism can be secured even when the engine is stopped. (For example, refer to Patent Document 1).

JP-A-11-132321

However, in the above-described conventional device, the hydraulic oil temperature exceeds the normal use temperature (eg, 100 ° C.) and becomes extremely high (eg, 150 ° C.) depending on the driving condition of the vehicle, and the kinematic viscosity of the hydraulic oil is significantly reduced. There is no special consideration.
Specifically, when the kinematic viscosity decreases as the temperature of the hydraulic oil rises, the amount of internal leakage of the hydraulic oil from the mechanical oil pump, clutch control linear solenoid valve, hydraulic adjustment relief valve, etc. that constitute the hydraulic circuit increases. . Due to the increase in the internal leak amount, there is a possibility that the required hydraulic pressure cannot be secured even if the electric oil pump is operated while the engine is stopped.

Here, when a hydraulically operated clutch that is operated with the above-described hydraulic pressure is employed in the hybrid electric vehicle, if the hydraulic pressure is insufficient due to an increase in the internal leak amount, an operation required for fastening the clutch when the engine is restarted. Since the hydraulic pressure is insufficient and the electric motor and the engine cannot be completely connected, there is a risk of starting failure of the engine due to the driving force of the electric motor.
Therefore, when the above-described internal leak of hydraulic oil is assumed, an electric oil pump having a high flow rate and high output that is higher than the internal leak is required to ensure the hydraulic pressure. Further, the extreme temperature rise of the hydraulic oil described above occurs only immediately after driving the vehicle with a high load in summer. Therefore, it is inevitably inferior to adopt a high-output electric oil pump, assuming a very low occurrence frequency, costing the electric oil pump, and increasing its size, weight, etc. .

In addition, when the hydraulic oil is hot, the pump's thermal deterioration occurs due to the flow of hot hydraulic oil in the pump, or the electric oil pump is operated unnecessarily for a long time due to engine start failure. There is also a risk that the service life will be significantly reduced.
Furthermore, there is a problem that operating the high-power electric oil pump for a long time increases the amount of electric power used in the vehicle, which in turn degrades the fuel consumption of the vehicle.

  The present invention has been made on the basis of the above-mentioned circumstances, and its object is to improve the reliability and durability of a hydraulic circuit that connects and disconnects a hydraulically operated clutch provided between an engine and an electric motor, and consequently An object of the present invention is to provide a control device for a hybrid electric vehicle capable of effectively preventing engine start failure by an electric motor via a clutch while realizing further downsizing, power saving, and fuel efficiency reduction of the vehicle.

  In order to achieve the above object, according to the control apparatus for a hybrid electric vehicle of the present invention, hydraulic oil is supplied by an engine that can be started by a driving force of a starter motor and a mechanical oil pump driven by the engine. A control apparatus for a hybrid electric vehicle, comprising: a hydraulic clutch; and an electric motor connected to the engine via the clutch, wherein the driving force of the engine and the driving force of the electric motor can be transmitted to driving wheels of a vehicle. The engine automatic start means for automatically starting the automatically stopped engine, the electric oil pump that is started by the engine automatic start means, pressurizes the hydraulic oil and supplies the clutch to the clutch, and the temperature of the hydraulic oil supplied to the clutch. Hydraulic oil temperature detecting means for detecting, and the engine automatic start means is detected by the hydraulic oil temperature detecting means When the hydraulic oil temperature is lower than the predetermined temperature, the electric oil pump is started, the clutch is connected by the hydraulic pressure of the hydraulic oil pressurized by the electric oil pump, the electric motor is started, and the engine is started by the driving force of the electric motor. On the other hand, when the hydraulic oil temperature detected by the hydraulic oil temperature detecting means is equal to or higher than a predetermined temperature, the starter motor is started and the engine is started by the driving force of the starter motor (claim 1).

Preferably, the engine automatic start means stops the electric oil pump after the engine is started when the hydraulic oil temperature detected by the hydraulic oil temperature detection means is lower than a predetermined temperature, and is pressurized by the mechanical oil pump. The clutch is connected / disconnected by the hydraulic pressure of the hydraulic oil.
Specifically, it includes a first oil passage that supplies hydraulic oil from the mechanical oil pump to the clutch, and a second oil passage that supplies hydraulic oil from the electric oil pump to the first oil passage.

  The second oil passage is provided with a check valve for preventing the backflow of hydraulic oil from the first oil passage to the electric oil pump.

  According to the control apparatus for a hybrid electric vehicle according to claim 1, when the hydraulic oil temperature detected by the hydraulic oil temperature detecting means is lower than a predetermined temperature, the engine automatic starting means starts the electric oil pump to The clutch is connected by the hydraulic pressure of the hydraulic oil pressurized by the pump, the electric motor is started and the engine is started by the driving force of the electric motor. On the other hand, the hydraulic oil temperature detected by the hydraulic oil temperature detecting means is not less than a predetermined temperature. When the starter motor is started, the engine is started by the driving force of the starter motor. As a result, when the hydraulic oil temperature is high, the automatically stopped engine can be automatically started with the driving force of the starter motor in the same manner as the normal manual engine start. Therefore, the internal leakage from the mechanical oil pump increases due to the decrease in the dynamic viscosity of the hydraulic oil, and as a result, the hydraulic pressure is insufficient and the clutch cannot be connected. Can be prevented.

In addition, since it is not necessary to assume an increase in internal leakage at the time of hydraulic oil high temperature when selecting an electric oil pump, the electric oil pump can be of a low output type that is assumed to be used only at the normal operating temperature of hydraulic oil. . Therefore, the cost, size, weight, etc. of the electric oil pump can be minimized.
Further, since the electric oil pump is not used when the hydraulic oil is hot, the electric oil pump is thermally deteriorated due to high temperature hydraulic oil flowing through the electric oil pump, and the electric oil pump is wasted for a long time due to engine start failure. Through proper use, it is possible to prevent the life of the electric oil pump from being significantly reduced.

Furthermore, by operating the electric oil pump unnecessarily for a long time or using the electric oil pump continuously at a high output, the amount of electric power used in the vehicle increases, and the fuel consumption of the vehicle deteriorates. Can be prevented.
As described above, the low-power electric oil pump can be operated efficiently, and the electric oil pump and the hydraulic circuit can be improved in reliability and durability at a low cost, and the vehicle can be further reduced in size and power consumption. Thus, it is possible to provide a control device for a hybrid electric vehicle that can realize low fuel consumption.

  According to the second aspect of the present invention, the engine automatic starting means stops the electric oil pump after starting the engine when the hydraulic oil temperature detected by the hydraulic oil temperature detecting means is lower than a predetermined temperature, The clutch is connected / disconnected by the hydraulic pressure of the hydraulic oil pressurized by the oil pump. This prevents the electric oil pump from being used unnecessarily for a long time because the use of the electric oil pump is limited only at the start of the engine, thereby further improving the durability of the electric oil pump and thus further updating the vehicle. Power saving and low fuel consumption can be realized.

  According to a third aspect of the present invention, the first oil passage for supplying the hydraulic oil from the mechanical oil pump to the clutch and the second oil passage for supplying the hydraulic oil from the electric oil pump to the first oil passage are included. As a result, a part of the oil passage for supplying hydraulic oil from the mechanical and electric oil pumps to the clutch can be shared to form the same hydraulic system, and the configuration of the hydraulic circuit is simplified. The leakage of hydraulic oil can be prevented as much as possible.

In addition, when an electric oil pump is added to the basic hydraulic circuit equipped with a mechanical oil pump later, it is not necessary to change the configuration of the basic hydraulic circuit, so that the manufacturing cost of the hydraulic circuit can be significantly reduced. Therefore, the reliability of the hydraulic circuit can be increased in a simple and low cost manner.
According to invention of Claim 4, the non-return valve which prevents the backflow of the hydraulic fluid from a 1st oil path to an electric oil pump is interposed by the 2nd oil path. As a result, it is possible to reliably prevent the backflow of hydraulic oil from the mechanical oil pump side to the electric oil pump side without changing the configuration of the basic hydraulic circuit. Reliability can be increased.

It is the block diagram which showed roughly the principal part longitudinal cross-section of the power transmission system of the hybrid electric vehicle to which this invention is applied. 2 is a flowchart showing an outline of engine automatic start control executed by the ECU of FIG. 1.

Hereinafter, embodiments of the present invention will be described with reference to the drawings.
FIG. 1 is a configuration diagram schematically showing a longitudinal section of a main part of a power transmission system of a hybrid electric vehicle 1 to which the present invention is applied. The hybrid electric vehicle 1 includes a clutch 6 that transmits the driving force of the engine 2 and the driving force of the electric motor 4 to the driving wheels of the vehicle and connects and disconnects the engine 2 and the electric motor 4.

  The output shaft of the engine 2 is connected to the input shaft of the clutch 6, and the output shaft of the clutch 6 is connected to the input shaft of the automatic transmission (hereinafter referred to as “transmission”) 8 through the rotating shaft of the electric motor 4. The output shaft of the transmission 8 is connected to the left and right drive wheels via a propeller shaft, a differential device and a drive shaft, although not shown in the figure. Therefore, when the clutch 6 is connected, both the output shaft of the engine 2 and the rotating shaft of the electric motor 4 are mechanically connected to the drive wheels, and when the clutch 6 is disconnected, only the rotating shaft of the electric motor 4 is connected. It will be in the state connected mechanically with the drive wheel.

  The electric motor 4 is a permanent magnet type synchronous motor, and although not shown in the drawings, the DC power stored in the battery is converted into AC power by an inverter and supplied as an electric motor. Is transmitted to the drive wheels after being shifted to an appropriate speed by the transmission 8. Further, when the vehicle is decelerated, the electric motor 4 operates as a generator, and kinetic energy generated by the rotation of the drive wheels is transmitted to the electric motor 4 through the transmission 8 and converted into AC power, thereby generating a regenerative braking force. Then, this AC power is converted into DC power by an inverter, and then charged to the battery, and the kinetic energy due to the rotation of the drive wheels is recovered as electric energy.

  On the other hand, the engine 2 can be started by the driving force of the starter motor 10 that is energized when an ignition key (not shown) is turned. The driving force of the engine 2 is the rotation of the electric motor 4 when the clutch 6 is connected. It is transmitted to the transmission 8 via the shaft, and is transmitted to the drive wheels after being shifted to an appropriate speed. Therefore, when the electric motor 4 operates as a motor when the driving force of the engine 2 is transmitted to the driving wheels, the driving force of the engine 2 and the driving force of the electric motor 4 are transmitted to the driving wheels, respectively. Become. That is, a part of the driving torque to be transmitted to the driving wheels for driving the vehicle is supplied from the engine 2, and the rest of the driving torque is supplied from the electric motor 4.

  The clutch 6 is a hydraulically operated wet type clutch, and connects and disconnects the engine 2 and the electric motor 4 with the hydraulic pressure of the hydraulic oil flowing through the hydraulic circuit 12. The hydraulic circuit 12 is a mechanical oil pump 14 driven by the engine 2 or the electric motor 4, a hydraulic pressure adjusting relief valve 13 that adjusts the hydraulic pressure of the hydraulic oil flowing through the hydraulic circuit 12 to a predetermined pressure, and a clutch 6 connection / disconnection control. A linear solenoid valve 15 for clutch control, an electric oil pump 16 that is started by a command from an ECU 42 described later, and a hydraulic oil temperature sensor that detects the temperature of hydraulic oil supplied to the clutch 6 (hydraulic oil temperature detection) Means) 18, and the hydraulic oil is pressurized by the mechanical oil pump 14 or the electric oil pump 16 and supplied to the clutch 6.

  A first suction pipe (first oil passage) 20 is connected to the suction port 14a of the mechanical oil pump 14, and the first suction pipe 20 extends to an oil pan 22 in which hydraulic oil is stored. A first discharge pipe (first oil passage) 24 is connected to the discharge port 14 b of the mechanical oil pump 14, and the first discharge pipe 24 extends to the clutch 6. The hydraulic oil sucked from the oil pan 22 by the mechanical oil pump 14 is pressurized by the mechanical oil pump 14 after passing through the first suction pipe 20 as indicated by an arrow in FIG. When passing through the pipe 24, the pressure is adjusted to a predetermined pressure by the hydraulic pressure adjusting relief valve 13 and supplied to the clutch 6 via the clutch control linear solenoid valve 15.

When the hydraulic pressure of the hydraulic oil pressurized by the mechanical oil pump 14 is higher than a predetermined pressure, a part of the hydraulic oil is transferred from the hydraulic pressure adjusting relief valve 13 to the oil pan 22 through the discharge pipe 23. Discharged. Further, a second suction pipe 30 that connects the first suction pipe 20 and the suction port 16 a of the electric oil pump 16 is connected to the first suction pipe 20.
On the other hand, a second discharge pipe (second oil passage) 34 is connected to the discharge port 16 b of the electric oil pump 16, and the other end of the second discharge pipe 34 is connected to the first discharge pipe 24.

Further, a check valve 36 is interposed in the second discharge pipe 34, and the check valve 36 sequentially passes through the second discharge pipe 34 from the first discharge pipe 24 to the hydraulic oil pump 16 side. Prevents backflow.
The hydraulic oil sucked from the oil pan 22 by the electric oil pump 16 is pressurized by the electric oil pump 16 after passing through the second suction pipe 30 as indicated by an arrow in FIG. The check valve 36 and a part of the first discharge pipe 24 are sequentially supplied to the clutch 6. That is, the oil passage from the electric oil pump 16 to the clutch 6 is formed by sharing a part of the first discharge pipe 24.

  Here, the engine 2 has a fuel injection / ignition control device 40 that performs fuel injection control and injection fuel ignition control for each cylinder 38. The operation of the fuel injection / ignition control device 40 is controlled by an ECU 42 that comprehensively controls the vehicle. The ECU 42 operates a so-called ISS (idling stop and start) system when a predetermined condition is satisfied, and the engine 2 is automatically stopped and started. Execute control.

  Specifically, the ECU 42 includes a vehicle speed sensor 44 that detects the vehicle speed, an engine water temperature sensor 46 that detects the temperature of cooling water that cools the engine 2, a brake switch 48 that detects whether or not the brake pedal has been depressed, A shift position sensor 50 that detects the shift position of the machine 8, an engine speed sensor that detects the speed of the engine 2, an accelerator pedal sensor that detects the amount of depression of the accelerator pedal, and a remaining capacity that detects the remaining capacity of the battery An output signal from a sensor (none of which is shown) is input.

  The ECU 42 turns on an ISS switch (not shown) for operating the ISS system, for example, the vehicle speed detected by the vehicle speed sensor 44 is zero, and the cooling detected by the engine water temperature sensor 46 is performed. When the water temperature is 60 ° C or higher, the brake switch 48 is on, and the shift position detected by the shift position sensor 50 satisfies the D (drive) or N (neutral) conditions, the engine 2 idling is automatically stopped. To do.

  Thereafter, the ECU 42 has an automatic start request for the engine 2 when, for example, the brake switch 48 is turned off when the shift position is D, or when the shift position is D when the shift position is N. The engine 2 is automatically restarted. Thus, the engine automatic stop / start control is executed by operating the fuel injection / ignition control device 40.

  Here, when executing the engine automatic stop / start control, the ECU 42 controls the drive of the electric oil pump 16 according to the operating oil temperature during the automatic start of the engine 2, so that the electric motor 4 serves as an automatic start means for the engine 2. Alternatively, the engine automatic start control capable of selecting any one of the starter motors 10 is executed (engine automatic start means). That is, the ECU 42, the fuel injection / ignition control device 40, and the hydraulic circuit 12 constitute a control device 52 for engine automatic starting means.

The engine automatic start control will be described below with reference to the flowchart of FIG.
First, when this control is started, it is determined in step S1 whether or not the engine 2 has been automatically stopped due to the establishment of the predetermined condition described above during operation of the ISS system with the ISS switch turned on. If it is determined by ISS that the engine 2 has been automatically stopped (Yes), the process proceeds to step S2, and if it is determined by ISS that the engine 2 has not been automatically stopped (No), the process returns to step S1 again.

Next, in step S2, it is determined whether or not there is an automatic start request for the engine 2 when the predetermined condition described above is satisfied. When it is determined that there is an automatic start request for the engine 2 (Yes), the process proceeds to step S3, and when it is determined that there is no request for automatic start of the engine 2 (No), the process returns to step S2.
Next, the hydraulic oil temperature is detected by the hydraulic oil temperature sensor 18 (step S3), and whether or not the hydraulic oil temperature T detected by the hydraulic oil temperature sensor 18 is lower than a predetermined temperature Tα (T <Tα). Determine (step S4). When it is determined that the hydraulic oil temperature T is lower than the predetermined temperature Tα (Yes), the process proceeds to Step S5, and when it is determined that the hydraulic oil temperature T is equal to or higher than the predetermined temperature Tα (No), Step S9 is performed. Migrate to The predetermined temperature Tα is higher than the normal operating temperature (eg, 100 ° C.) of the hydraulic oil, and the increase in internal leakage due to the decrease in kinematic viscosity does not exceed the pump performance of the electric oil pump 16 required for engaging the clutch 6. Is set to a temperature range (for example, about 110 ° C. to 120 ° C.).

Next, in step S5, the electric oil pump 16 is started, the clutch 6 is connected by the hydraulic oil pressure pressurized by the electric oil pump 16 (step S6), the electric motor 4 is started (step S7), and the electric motor 4 The engine 2 is started by the driving force (step S8), and the process proceeds to step S10.
On the other hand, if it is determined in step S4 that the hydraulic oil temperature T is equal to or higher than the predetermined temperature Tα (No), the starter motor 10 is started (step S9), and the engine 2 is started by the driving force of the starter motor 10. (Step S8), the process proceeds to Step S10.

Finally, in step S10, when the electric oil pump 16 is operating through step S5, the electric oil pump 16 is stopped and this control is ended.
As described above, in the present embodiment, by executing the engine automatic start control described above, the automatic stop of the engine 2 that has been automatically stopped is performed in the same way as the normal manual start of the engine 2 at the time when the hydraulic oil temperature is high. This can be done with the driving force of the starter motor 10. Accordingly, the internal oil leakage from the mechanical oil pump 14, the hydraulic pressure adjusting relief valve 13, the clutch control linear solenoid valve 15 and the like constituting the hydraulic circuit 12 is increased due to a decrease in the dynamic viscosity of the hydraulic oil, and the hydraulic pressure is insufficient. Thus, the clutch 6 cannot be connected, and as a result, it is possible to effectively prevent the engine 2 from failing to start.

In addition, since it is not necessary to assume an increase in internal leakage when the hydraulic oil is hot when selecting the electric oil pump 16, the electric oil pump 16 should be of a low output type that is assumed to be used only at the normal operating temperature of the hydraulic oil. Can do. Therefore, the cost, size, weight, etc. of the electric oil pump 16 can be minimized.
In addition, since the electric oil pump 16 is not used when the hydraulic oil is hot, the electric oil pump 16 is caused by thermal deterioration due to high-temperature hydraulic oil flowing through the electric oil pump 16 or the start failure of the engine 2. It is possible to prevent the life of the electric oil pump 16 from being significantly reduced by uselessly for a long time.

Furthermore, by operating the electric oil pump 16 unnecessarily for a long time or by continuously using the electric oil pump 16 at a high output, the amount of electric power used in the vehicle increases, and the fuel consumption of the vehicle deteriorates. Can be prevented.
Further, by performing the engine automatic start control described above, the electric oil pump 16 is stopped after the engine 2 is started when the hydraulic oil temperature T detected by the hydraulic oil temperature sensor 18 is lower than the predetermined temperature Tα. (Step S10). That is, after the engine 2 is automatically started, the clutch 6 is connected / disconnected by the hydraulic pressure of the hydraulic oil pressurized by the mechanical oil pump 14. As a result, the use of the electric oil pump 16 is limited only when the engine 2 is started, so that it is possible to prevent the electric oil pump 16 from being used unnecessarily for a long time, thereby improving the durability of the electric oil pump 16 and thus. Further power saving and fuel efficiency reduction of the vehicle can be realized.

Furthermore, the second discharge pipe 34 is connected to the first discharge pipe 24, so that a part of the oil passage for supplying the hydraulic oil to the clutch 6 from the mechanical and electric oil pumps 14, 16 is shared. Since the hydraulic system can be provided and the configuration of the hydraulic circuit 12 is simplified, leakage of hydraulic oil from the hydraulic circuit 12 can be prevented as much as possible.
In addition, when the electric oil pump 16 is added later to the basic hydraulic circuit provided with the mechanical oil pump 14 and disposed in the case 28, the additional circuit other than the basic hydraulic circuit is connected to the electric oil pump 16 and the second hydraulic oil circuit. It can be added by simply connecting the second suction pipe 30 to the first suction pipe 20. Accordingly, since it is not necessary to change the configuration of the basic hydraulic circuit significantly, the manufacturing cost of the hydraulic circuit 12 can be greatly reduced.

Specifically, when a large change occurs in the arrangement of the basic hydraulic circuit and the pipes constituting the basic hydraulic circuit in the case 28, the breakdown voltage and heat resistance of each device arranged in the case 28 including the basic hydraulic circuit are increased. Forced to change the design. However, in the present embodiment, since the configuration of the basic hydraulic circuit does not need to be significantly changed, the reliability of the hydraulic circuit 12 can be improved easily and at low cost.
In addition, since the check valve 36 is interposed in the second discharge pipe 34, the hydraulic oil can flow back from the mechanical oil pump 14 side to the electric oil pump 16 side without changing the configuration of the basic hydraulic circuit. This can be reliably prevented, and the reliability of the hydraulic circuit 12 can be increased with simplicity and low cost.

  As described above, the low-power electric oil pump 16 is efficiently operated in order to connect and disconnect the clutch 6 provided between the engine 2 and the electric motor 4, and the electric oil pump 16 and thus the hydraulic pressure are simplified and low-cost. It effectively prevents the engine 2 from failing to start by the motor 4 via the clutch 6 while improving the reliability and durability of the circuit 12 and thus further reducing the size, power consumption and fuel consumption of the vehicle. A control device of the possible hybrid electric vehicle 1 can be provided.

The present invention is not limited to the above-described embodiment, and various modifications can be made.
For example, the predetermined temperature Tα is higher than the normal operating temperature (eg, 100 ° C.) of the hydraulic oil, and the increase in internal leakage due to the decrease in kinematic viscosity does not exceed the pump performance of the electric oil pump 16 required for engaging the clutch 6. The temperature range of the hydraulic oil is set to, for example, about 110 ° C. to 120 ° C., but this temperature range naturally varies depending on the type of hydraulic oil used.

DESCRIPTION OF SYMBOLS 1 Hybrid electric vehicle 2 Engine 4 Electric motor 6 Clutch 10 Starter motor 14 Mechanical oil pump 16 Electric oil pump 18 Hydraulic oil temperature sensor (hydraulic oil temperature detection means)
20 First suction pipe (first oil passage)
24 First discharge pipe (first oil passage)
30 Second suction pipe (second oil passage)
34 Second discharge pipe (second oil passage)
36 Check valve 42 ECU (automatic engine starting means)
52 Control device

Claims (4)

An engine that can be started by a driving force of a starter motor; a hydraulic clutch that is supplied with hydraulic oil by a mechanical oil pump that is driven by the engine; and an electric motor that is connected to the engine via the clutch. A control device for a hybrid electric vehicle capable of transmitting the driving force of the engine and the driving force of the electric motor to driving wheels of a vehicle,
An engine automatic starting means for automatically starting the engine that has been automatically stopped;
An electric oil pump that is started by the engine automatic starting means, pressurizes the hydraulic oil, and supplies the hydraulic oil to the clutch;
Hydraulic oil temperature detecting means for detecting the temperature of the hydraulic oil supplied to the clutch,
The engine automatic start means starts the electric oil pump when the hydraulic oil temperature detected by the hydraulic oil temperature detection means is lower than a predetermined temperature, and uses the hydraulic pressure of the hydraulic oil pressurized by the electric oil pump. The starter motor is connected when the clutch is connected, the electric motor is started and the engine is started by the driving force of the electric motor, and when the hydraulic oil temperature detected by the hydraulic oil temperature detecting means is equal to or higher than the predetermined temperature. And start the engine by the driving force of the starter motor ,
The predetermined temperature is set in a temperature range that is higher than the normal use temperature of the hydraulic oil, and an increase in internal leak due to a decrease in kinematic viscosity does not exceed the pump performance of the electric oil pump required for engaging the clutch. Control device for hybrid electric vehicle.   The engine automatic start means stops the electric oil pump after the engine is started when the hydraulic oil temperature detected by the hydraulic oil temperature detection means is lower than a predetermined temperature, and applies the mechanical oil pump. 2. The control apparatus for a hybrid electric vehicle according to claim 1, wherein the clutch is connected / disconnected by the hydraulic pressure of the pressurized hydraulic oil.   A first oil passage for supplying hydraulic oil from the mechanical oil pump to the clutch, and a second oil passage for supplying hydraulic oil from the electric oil pump to the first oil passage are included. 2. A control apparatus for a hybrid electric vehicle according to 2.   The control of a hybrid electric vehicle according to claim 3, wherein a check valve for preventing a backflow of hydraulic oil from the first oil passage to the electric oil pump is interposed in the second oil passage. apparatus.

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