JP2001041067A - Vehicle - Google Patents

Abstract

PROBLEM TO BE SOLVED: To depart a vehicle smartly when a mechanical pump driven by an engine and an electric pump driven by the electric power from a battery are provided. SOLUTION: In a vehicle, a controller 44 having such function 45 that an engine 41 is automatically stopped after a prescribed delay term when a prescribed running condition is realized and the engine 41 is restarted when another prescribed running condition is realized, a mechanical pump 46 driven by the engine 41, an electric pump 47 driven by the electric power from a battery and the means 48 for supplying an oil pressure produced by these pumps 46, 47 to an automatic transmission 43 are provided. The controller 44 is provided with the function 49 for starting the operation of the electric pump 47 in the delay time.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a vehicle for automatically stopping and restarting an engine.

[0002]

2. Description of the Related Art When a vehicle temporarily stops at a traffic light or the like while driving, the engine is automatically stopped, and when the vehicle is started, the engine is automatically restarted to thereby improve fuel efficiency. There is a vehicle having an engine automatic stop / restart function designed to improve the engine speed.
No. 25).

[0003]

By the way, in the case where the operating hydraulic pressure is supplied to the automatic transmission by the mechanical pump driven by the engine, when the engine is stopped by the automatic stop of the engine, the hydraulic pressure is supplied to the automatic transmission. In addition to the mechanical pump, an electric pump driven by a battery is provided in addition to the mechanical pump, and when the engine is stopped and a start / start operation such as depressing an accelerator pedal is performed, the electric pump is activated to raise the hydraulic pressure. There is a vehicle in which the forward clutch is shifted to a starting shift state, and then the engine is automatically restarted to start the engine (Japanese Patent Laid-Open No. Hei 8-
No. 14076).

However, even if the electric pump is operated, the oil pressure does not rise immediately, so that if the operation of the electric pump is performed at the same time as the start / start operation, the hydraulic pump is directly affected by a delay in the rise of the oil pressure of the electric pump. That is, if the engine is started and the vehicle is started after the hydraulic pressure of the electric pump has risen, the vehicle cannot be started quickly. On the other hand, if the engine is started without waiting for the hydraulic pressure to rise, the engine will blow up greatly due to insufficient engagement of the forward clutch, and a torque shock will occur when the clutch is subsequently engaged.

[0005] Therefore, the present invention is to start the operation of the electric pump and hold the oil pressure in a rising state within a delay period from when the condition for automatically stopping the engine is satisfied to when the engine is actually stopped. Therefore, it is an object of the present invention to enable an agile vehicle to start.

[0006]

According to a first aspect of the present invention, as shown in FIG. 10, an engine 41, an electric motor 42 rotating in synchronization with the engine 41, and outputs of the engine 41 and the electric motor 42 are applied to driving wheels. A controller having an automatic transmission 43 for transmitting a signal and a function 45 for automatically stopping the engine 41 after a predetermined delay period DLY when a predetermined operating condition is satisfied and restarting the engine 41 when another predetermined operating condition is satisfied. 44 (the drawing does not show the connection state of the engine, electric motor, and transmission), the mechanical pump 4 driven by the engine 41
6 and an electric pump 47 driven by electric power from a battery
And means 48 for supplying the hydraulic pressure generated by these pumps 46 and 47 to the automatic transmission 43. The controller 44 has a function 49 for starting the operation of the electric pump 47 within the delay time DLY. .

In a second aspect of the present invention, in the first aspect, a means for detecting a hydraulic pressure generated by the electric pump is provided, and when the detected hydraulic pressure is not equal to or more than a predetermined value Pt0 at the end of the delay period, the engine is started. Prohibit suspension.

According to a third aspect of the present invention, in the first aspect, the target hydraulic pressure value of the electric pump is individually set during the delay period and during the subsequent engine stop, and the target hydraulic pressure value Pt1 during the delay period is set thereafter. The pressure is set lower than the target oil pressure value Pt2 when the engine is stopped.

According to a fourth aspect of the present invention, in the third aspect, the hydraulic pressure target value Pt1 during the delay period is set within a range that does not cause a large delay in following the hydraulic pressure when the engine shifts to the subsequent engine stop state during the delay period. I do.

In a fifth aspect based on the third aspect, the target hydraulic pressure values Pt1 and Pt2 of the electric pump during the delay period and during the subsequent engine stop are changed according to the oil temperature.

According to a sixth aspect, in the first aspect, the waiting period Tp until the operation of the electric pump is started is changed according to the oil temperature.

According to a seventh aspect of the present invention, in any one of the first to sixth aspects, the supply destination of the hydraulic pressure from the hydraulic pressure supply means to the automatic transmission is an element required for starting the vehicle in the automatic transmission. (For example, the hydraulic chamber of the forward / reverse clutch and the pulley hydraulic chamber when the automatic transmission is a CVT).

[0013]

According to the first aspect of the present invention, the operation of the electric pump is started during the delay period, so that the hydraulic pressure of the electric pump rises before the engine is stopped.
That is, even if the engine and the mechanical pump are stopped due to the end of the delay period, the hydraulic pressure of the electric pump rises, so that the hydraulic pressure of the transmission is continuously maintained. Therefore, even if a start / start operation such as depressing the accelerator pedal is performed immediately after shifting to the engine stopped state, it is possible to start the engine immediately, connect the forward clutch and start the vehicle promptly, and delay the clutch engagement. No engine blow-up or torque shock occurs.

According to the second aspect, at the end of the delay period, it is possible to prevent a situation in which the engine and the mechanical pump are stopped without raising the hydraulic pressure of the electric pump and the hydraulic pressure of the transmission is reduced. Thus, even if the start-start operation is performed immediately after the end of the delay period, the engine can be started and the clutch can be immediately engaged.

According to the third aspect, the drive load of the electric pump is reduced due to the decrease in the target hydraulic pressure during the delay period, so that the power consumption can be reduced accordingly.

According to the fourth aspect of the present invention, the target hydraulic pressure can be immediately secured when shifting to the engine stopped state, so that the vehicle can be started immediately after shifting to the engine stopped state.

Since it is considered that the higher the oil temperature, the faster the hydraulic pressure of the electric pump rises, according to the fifth aspect, the target hydraulic pressure of the electric pump can be set as low as possible in accordance with the state of the oil temperature. Power consumption as a result.

According to the sixth aspect of the invention, when the temperature is relatively high and the hydraulic pressure rises quickly, the operation start timing of the electric pump can be delayed, so that the operation period of the electric pump is shortened and power consumption is reduced. Can save.

According to the seventh aspect, the flow rate of oil leakage while the engine is stopped can be minimized. As a result, the load on the electric pump can be reduced, and the power consumption can be reduced.

[0020]

DESCRIPTION OF THE PREFERRED EMBODIMENTS In FIG.
Denotes a continuously variable automatic transmission, between which a motor generator (electric motor) 2 is disposed. The rotation of engine 1 or motor generator 2 is transmitted from continuously variable automatic transmission 3 to drive wheels (not shown) via drive shaft 7.

The engine 1 may be a gasoline engine or a diesel engine.
Further, a stepped automatic transmission with a torque converter or a start clutch can be used instead of the continuously variable automatic transmission 3.

The continuously variable automatic transmission 3 includes a torque converter 4
, A forward / backward switching mechanism 5, and a metal belt 6 looped between variable pulleys 6a, 6b.
By changing the pulley ratio of 6b, the speed ratio transmitted through the metal belt 6 changes. In order to drive the variable pulleys 6a and 6b such that the target speed ratio of the continuously variable automatic transmission 3 is set in accordance with the operation state and matches the actual speed ratio which is the ratio of the input speed to the output speed. Primary hydraulic pressure and secondary hydraulic pressure are controlled.

The forward / reverse switching mechanism 5 reverses the direction of output rotation between forward and reverse travels. The torque converter 4 transmits input rotational torque to the output side via fluid force, and the input side pole Stoppage of rotation on the output side such as during low-speed rotation can be tolerated.

The motor generator 2 is connected directly to the crankshaft of the engine 1 or connected via a belt or a chain, and rotates in synchronization with the engine 1. The motor generator 2 functions as a motor or a generator, and the power control unit 12 controls the function, the number of revolutions, the amount of power generation, and the like.

When the motor generator 2 functions as a motor supplementing the output of the engine 1 or as a motor for starting the engine 1, the current from the battery 13 is supplied via the power control unit 12 and the vehicle When the battery 13 functions as a generator in order to recover the traveling energy of the vehicle, the battery 13 is charged by the current generated through the power control unit 12.

When the vehicle is temporarily stopped or the like, the engine is automatically stopped, and when the vehicle is started thereafter, the engine 1 is stopped.
An automatic stop / restart controller 10 is provided for automatically restarting the engine 1 when the vehicle stops and the engine 1 is stopped by the motor generator 2 when the vehicle starts moving.

Therefore, the automatic stop / restart controller 1
0 indicates the engine speed sensor 9 and the brake sensor 1
1. Signals from the accelerator sensor 15, the shift position sensor 17 of the continuously variable automatic transmission 3, the vehicle speed sensor 18, and the like are input, and the automatic stop and start are controlled based on these signals.

The vehicle is provided with a mechanical pump driven by an engine and an electric pump driven by a battery in order to supply working hydraulic pressure to the continuously variable automatic transmission 3.

Referring to FIG. 2, a mechanical pump 21 is connected to the torque converter 2, and when the engine is operating, the hydraulic pressure generated by the mechanical pump 21 is applied to the line pressure control valve. The pressure is adjusted by 22, and the adjusted oil pressure is supplied to a hydraulic chamber 24 of the forward / reverse clutch via a hydraulic supply passage 23.

Further, a shutoff valve 27 is interposed in a hydraulic supply passage 25 which connects the mechanical pump 21 and a pulley hydraulic chamber 26 of the continuously variable automatic transmission, and the shutoff valve 27 is opened during operation of the engine. The regulated hydraulic pressure is also supplied to the pulley hydraulic chamber 26 of the continuously variable automatic transmission. In this case, the check valve 28 can prevent the hydraulic pressure from the mechanical pump 21 from being transmitted to the electric pump 14.

On the other hand, the electric pump 14 is
And supplies the required hydraulic pressure to the hydraulic chamber 24 of the forward / reverse clutch and the pulley hydraulic chamber 26 of the continuously variable automatic transmission regardless of the operation of the engine. In this case, by shutting off the shutoff valve 27, it is possible to prevent the hydraulic pressure from the electric pump 14 from being transmitted to the mechanical pump 21.

Reference numeral 31 denotes a relief valve which opens when the discharge pressure of the electric pump 14 exceeds a specified value and returns oil to the electric pump 14. A manual valve 32 has a function of releasing the hydraulic pressure of the forward clutch.

The above-mentioned electric pump 14 is also controlled by the automatic stop / restart controller 10. When a start / start operation such as depressing an accelerator pedal while the engine is stopped is performed, the forward clutch is immediately engaged to start the vehicle. In order to allow the engine to start, the operation of the electric pump 14 is started within a delay period from when the condition for automatically stopping the engine is satisfied to when the engine is stopped, and the hydraulic pressure is maintained in a rising state.

This will be described with reference to FIG. 3. If the vehicle is stopped at the timing of t0 in the idling state, a condition for automatically stopping the engine is established at the timing of the stop of the vehicle at t0, and the delay period DLY is started from this t0.
The engine is actually stopped at t2, which is the timing when has elapsed. Therefore, until the timing of t2, a sufficient transmission oil pressure (line pressure of the transmission) is maintained by the operation of the mechanical pump, but the oil pressure of the mechanical pump decreases to zero from the timing of t2.

In this case, the automatic stop / restart controller 10 starts the operation of the electric pump at the timing t1 when the waiting period Tp has elapsed from the start t0 of the delay period DLY. At this time, during the delay period, the target hydraulic pressure value of the electric pump is set to a lower value Pt1, and the delay period D
After LY has passed, the target hydraulic pressure is set to a value P larger than Pt1.
Increase to t2. Then, from the timing t3 when the start-start operation is performed thereafter, the hydraulic pressure target value is increased to a value Pt3 that is larger than Pt2.

If the hydraulic pressure generated by the electric pump becomes higher due to a decrease in the hydraulic pressure of the mechanical pump from the engine stop timing t2, the oil flows backward from the electric pump to the mechanical pump. In order to prevent this, shut-off valve 27
Close.

On the other hand, when the engine is restarted by the start-start operation, the hydraulic pressure rises due to the operation of the mechanical pump. Therefore, it is determined that the hydraulic pressure by the mechanical pump is sufficient t4.
The operation of the electric pump is stopped at the timing of
Open the shutoff valve.

Next, the contents of the control executed by the controller 10 will be described with reference to the following flowchart.

First, FIG. 4 is for performing the process of automatically stopping and restarting the engine, and is performed at regular intervals (for example, every 10 ms).
ec).

In step 1, it is determined whether or not the condition for permitting idle stop (automatic stop) is satisfied. Here, the idle stop permission condition includes, for example, the following.

The state of charge (SOC) of the battery is within a predetermined range.

The cooling water temperature of the engine is within an appropriate range (for example, after completion of warm-up).

When all of the above two conditions are satisfied, it is determined that the idle stop permission condition is satisfied, and the process proceeds to steps 2, 3, 4, 5, and 6, and the vehicle speed sensor 1
8, the state of the brake pedal detected by the brake sensor 11, the state of the accelerator pedal detected by the accelerator sensor 15, the automatic stop prohibition flag, and the engine speed. Vehicle speed = 0 km / h, brake pedal depressed, accelerator pedal not depressed, automatic stop prohibition flag =
If the condition of 0 is satisfied, but is not in the idling rotation range (for example, 800 rpm or less), the current process is terminated as it is. The setting of the automatic stop prohibition flag will be described later with reference to FIG.

When all of the above conditions (i.e., idling speed range) are satisfied,
Proceeding to step 7, it is determined whether or not all of the above conditions are satisfied for the first time by the flag FCOND (0
Judge from the initial setting).

When FCOND = 0 (when the condition is satisfied for the first time), step 8 is executed to start the engine stop processing.
To set the flag FCOND = 1 and a delay period (for example, the delay time D
LY) is set. As the delay time DLY, for example, about 2 seconds is set.

In step 9, it is determined whether the engine is stopped. If the engine is stopped, the current process is terminated. When the engine is not stopped, the process proceeds from step 9 to step 10 where the counter Td for measuring the elapsed time after setting the delay time DLY is compared with the delay time DLY.
If Y is exceeded, an engine stop process is executed in step S12. In this process, for example, the generated torque of motor generator 2 is set to zero, and fuel injection of engine 1 is stopped. As the counter Td, for example, a timer built in the controller 10 may be used.

On the other hand, when any of the above conditions is deviated, that is, when the brake pedal is released, the accelerator pedal is depressed, or the vehicle speed is not zero, In step 13, the flag FCOND is set to "0". Then, it is determined whether or not the engine is stopped in step S14. If the engine is stopped, the process proceeds to step S15 to perform processing for restarting the engine.

The value of the flag FCOND is RA
Save it in M.

FIG. 5 is for executing the prohibition determination of the automatic engine stop, and is performed at regular time intervals (for example, every 10 msec).
Every).

When the idle stop permission condition is satisfied in step 21, the delay counter Td used in FIG. 4 is read in step 22, and this is compared with the above-mentioned delay time DLY in step 23.

When the counter Td exceeds the delay time DLY, the process proceeds to step 24, where the sensor 33 (FIG. 2)
) Is read, and the actual oil pressure generated by the electric pump 14 is read and compared with a predetermined value Pt0 in step 25. Here, the predetermined value Pt0 is a determination value for determining whether to prohibit the automatic stop of the engine.
If t0 or less, the automatic stop prohibition flag is set to 1 in step 26 to prohibit the automatic stop of the engine. Because of this flag = 1, it is not possible to proceed to step 6 and subsequent steps in FIG. 4, so that the automatic stop of the engine is prohibited.

This is because when the rise of the hydraulic pressure of the electric pump 14 has not reached the predetermined value Pt0 or more at the end of the delay period, the engine is prohibited from being stopped. This is to avoid a situation where the hydraulic pump 21 stops and the hydraulic pressure of the transmission decreases. As a result, even if the start operation is performed immediately after the end of the delay period, the clutch can be immediately engaged and the vehicle can be started immediately, which may cause an engine blow-up or a torque shock due to the clutch engagement delay. Absent.

On the other hand, when the actual oil pressure exceeds the predetermined value Pt0, there is no need to prohibit the automatic stop of the engine, so the routine proceeds to step 27, where the automatic stop prohibition flag is set to "0".

FIGS. 6 and 7 are for controlling the electric pump 14, which is also performed at regular intervals (for example, 10 msec.).
Every).

In FIG. 6, in step 41, the flag FCOND stored in the RAM is checked. FCOND =
If it is 1, the routine proceeds to step 42, where it is determined whether or not the engine is stopped. If the engine is not stopped (that is, either during the delay period or when the automatic stop prohibition flag is set to 1), the process proceeds to step 43, and the operation state of the electric pump 14 is checked.

When the electric pump 14 is not operating,
The delay counter Td used in FIG.
, And compares it with a predetermined value Tp in step 45. Here, the predetermined value Tp determines the operation standby time of the electric pump 14. For this reason, when Td is equal to or less than Tp, the process proceeds to step 46 to hold the electric pump in a non-operation state, and when Td exceeds Tp, it is determined that the operation timing of the electric pump has come, and the process proceeds to steps 47 and 48, The predetermined value Pt1 (Pt1> Pt0) is set as the target hydraulic pressure value Pt of the electric pump, and the operation of the electric pump is started. From the next time, the process proceeds from step 43 to steps 47 and 48 until the engine is stopped.
As a result, the hydraulic pressure generated by the electric pump becomes a predetermined value Pt1.
Is controlled to

Here, the predetermined value Pt1, which is the target oil pressure during the delay period, is set to be lower than a predetermined value Pt2, which is the target oil pressure during the subsequent stop of the engine (to be described later). If the target hydraulic pressure is set lower, the driving load of the electric pump is reduced, so that the power consumption can be reduced accordingly. Further, by determining the value of Pt1 within a range in which the target oil pressure can be immediately secured at the time of transition to the engine stop state, vehicle startability immediately after the transition to the engine stop state can also be secured.

The shutoff valve 27 is kept open until the end of the delay period (steps 42 and 49).

Thereafter, when the engine is stopped, the process proceeds from step 42 to step 50, where a predetermined value Pt2 (Pt2
After setting 2> Pt1) as the target hydraulic pressure value Pt of the electric pump, the process of step 51 is executed. Steps 50 and 51 are repeated until the start / start operation is performed from the next time, whereby the hydraulic pressure generated by the electric pump is increased to the predetermined value Pt2.

At this time, the shutoff valve 27 is closed (steps 42 and 52). This is to prevent the hydraulic pressure of the mechanical pump from decreasing due to the stop of the engine, and to prevent the oil from flowing backward from the electric pump toward the mechanical pump due to the decrease in the hydraulic pressure of the mechanical pump.

On the other hand, when the flag FCOND becomes 0, the process proceeds from step 41 in FIG. 6 to step 53 in FIG. When the vehicle is starting and starting, at step 54, a predetermined value Pt3 (Pt3> Pt2) is set as the hydraulic pressure target value Pt of the electric pump.
6 is executed. Here, the predetermined value Pt3 is a hydraulic pressure target value at the time of starting and starting. Steps 54, 55, and 56 will be repeated until the start / start operation is completed from the next time, whereby the hydraulic pressure generated by the electric pump is further increased to the predetermined value Pt3.

On the other hand, when the start / start operation is not being performed, such as when the start / start operation is completed, the process proceeds from step 53 to steps 57 and 58, in which the electric pump is deactivated and the shut-off valve 27 is opened.

The above-mentioned operation standby time Tp and each predetermined value Pt
Although 0, Pt1, Pt2, and Pt3 may be constant values, they are determined here by searching a table containing FIGS. 8 and 9 from the transmission oil temperature at that time.
The reason why the value is set lower as the oil temperature rises is that the oil pressure of the electric pump rises faster as the oil temperature rises.

Here, the operation and effect of this embodiment will be described with reference to FIG. 3 again.

In this embodiment, the operation of the electric pump 14 is started at t1 during a delay period until the engine is stopped. During the delay period, the required hydraulic pressure is obtained by the mechanical pump 21, and therefore the hydraulic pressure by the electric pump 14 is not originally necessary. Therefore, the oil pressure of the electric pump 14 during the delay period is controlled to a smaller value Pt1 so that the oil pressure of the electric pump 14 can quickly rise while the engine is stopped after the end of the delay period. As a result, the driving load of the electric pump 14 is reduced, so that the power consumption can be reduced accordingly.

Further, since the predetermined value Pt1 is determined within a range that does not cause a large delay in following the hydraulic pressure when shifting to the engine stop state after the delay period, the target oil pressure is immediately secured when shifting to the engine stop state. As a result, vehicle startability immediately after the shift to the engine stopped state can be ensured.

When the engine is stopped at the end of the delay period, the hydraulic pressure of the electric pump 14 rises responsively to the predetermined value Pt2, so that even if the operation of the mechanical pump is stopped due to the stop of the engine, the hydraulic pressure of the transmission is reduced. Calms down at a certain value without drastically decreasing.

When the start-start operation is performed in this state, the hydraulic pressure of the electric pump rises responsively to Pt3, which is higher than the predetermined value Pt2. At this time, the hydraulic pressure of the transmission exceeds the required hydraulic pressure (the minimum hydraulic pressure required to transmit the engine torque to the transmission without causing the engine to blow up) and quickly recovers to the value before the engine was stopped. (That is, the hydraulic pressure of the transmission required at the time of restart is restarted instantaneously), so that the engine can be started and the vehicle can be restarted with the clutch engaged quickly and smoothly.

As described above, according to the present embodiment, the hydraulic pressure of the electric pump is increased in advance during the delay period before shifting to the engine stop state, so that the hydraulic pressure of the transmission greatly decreases while the engine is stopped. Since the starting and restarting state is always maintained without starting, the starting and restarting can be performed quickly and smoothly.

[Brief description of the drawings]

FIG. 1 is a schematic configuration diagram showing a configuration of an embodiment of the present invention.

FIG. 2 is a schematic hydraulic supply circuit diagram of the automatic transmission.

FIG. 3 is a waveform chart for explaining the operation of the embodiment.

FIG. 4 is a flowchart illustrating a process of automatically stopping and restarting the engine.

FIG. 5 is a flowchart for explaining a prohibition determination of an automatic engine stop.

FIG. 6 is a flowchart illustrating control of the electric hydraulic pump.

FIG. 7 is a flowchart illustrating control of the electric hydraulic pump.

FIG. 8 is a characteristic diagram of an operation standby time Tp.

FIG. 9 is a graph showing characteristics of predetermined values Pt0, Pt1, Pt2, and Pt3.

FIG. 10 is a diagram corresponding to claims of the first invention.

[Explanation of symbols]

 Reference Signs List 1 engine 2 motor generator 3 stepless automatic transmission 10 automatic stop / restart controller 14 electric pump 21 mechanical pump 27 shut-off valve

──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. ⁷ Identification symbol FI Theme coat ゛ (Reference) F02D 29/00 F02D 29/00 H 3J052 41/04 330 41/04 330H F16H 61/00 F16H 61/00 / / B60K 6/02 B60K 9/00 C F16H 59:72 63:06 F term (reference) 3D037 FA13 FB00 FB05 3D039 AA01 AA02 AA04 AB27 AC01 AC34 AC36 AC45 AD06 AD43 AD44 AD53 3D041 AA30 AA53 AA68 AB00 AC01 AC02 AD20 AC20 AD10 AD31 AD41 AD51 AE02 AE08 AE31 AE39 AF00 3G093 AA05 AA06 AA07 AA11 AB01 BA03 BA19 BA21 BA22 CA01 CA02 CA04 CB05 DA01 DA04 DA06 DB05 DB10 DB11 DB15 DB19 DB23 EA05 EB03 EB05 FA11 FB04 3G301 HA04 KA04 JA02 NC08 NE21 PE01Z PE08Z PF01Z PF03Z PF05Z PF06Z PF08Z PG01Z 3J052 AA04 AA11 AA20 CA31 CB01 CB16 EA03 EA06 FA01 FB25 FB31 GC04 GC1 3 GC23 GC44 GC46 GC64 GC73 HA01 HA11 KA01 LA01

Claims (7)

[Claims] An engine, an electric motor rotating in synchronization with the engine, an automatic transmission for transmitting the output of the engine and the electric motor to drive wheels, and an engine after a predetermined delay period when predetermined operating conditions are satisfied. A vehicle equipped with a controller having a function of automatically stopping and restarting an engine when another predetermined operating condition is satisfied, a mechanical pump driven by the engine, and an electric pump driven by electric power from a battery And means for supplying the hydraulic pressure generated by these pumps to the automatic transmission,
A vehicle, wherein the controller has a function of starting operation of the electric pump within the delay time. 2. The system according to claim 1, further comprising means for detecting a hydraulic pressure generated by said electric pump, and prohibiting the engine from being stopped when the detected hydraulic pressure does not exceed a predetermined value at the end of the delay period. Item 4. The vehicle according to Item 1. 3. An oil pressure target value of the electric pump is set individually during the delay period and during the subsequent engine stop,
2. The hydraulic pressure target value during a delay period is set lower than a hydraulic pressure target value during a subsequent engine stop.
The vehicle described in the above. 4. The hydraulic pressure target value during the delay period is set within a range that does not cause a significant delay in following the hydraulic pressure when the engine is stopped during the delay period. The vehicle described. 5. The vehicle according to claim 3, wherein a target oil pressure value of the electric pump is changed according to an oil temperature during the delay period and during the subsequent stop of the engine. 6. The vehicle according to claim 1, wherein a standby period until the operation of the electric pump is started is changed according to an oil temperature. 7. The automatic transmission according to claim 1, wherein a supply destination of the hydraulic pressure from the hydraulic pressure supply means to the automatic transmission is limited to an element necessary for starting the vehicle in the automatic transmission. Vehicle described in one.