JP2000213389A - Idle stop vehicle - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prevent racing of an engine from being generated in restarting of the engine, in an idle stop vehicle. SOLUTION: A hydraulic control circuit 100 of an idle stop vehicle is provided with a transmission oil pressure holding/supplying circuit 9 capable of holding oil pressure from a hydraulic pump 14 and also capable of supplying the oil pressure to a transmission 17. When an engine 1 is restarted during idle stop, oil pressure is supplied from the transmission oil pressure holding/supplying circuit 9 to the transmission 17, and the engine speed of the engine 1 is increased after the specified time passes after from the time when the oil pressure is supplied to the transmission 17. Therefore, sufficient oil pressure is supplied to the continuously variable transmission 17 at the time when the engine speed of the engine 1 is raised, disengagement of a power transmission element caused by oil pressure response delay can be prevented, and racing of the engine can be prevented.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an idle stop vehicle for automatically stopping an engine when the vehicle stops.

[0002]

2. Description of the Related Art There is known an idling stop vehicle which suppresses fuel consumption and reduces exhaust gas by automatically stopping and restarting an engine at a traffic light or the like at an intersection.

[0003] In such an idle stop vehicle, when the engine stops, the oil pump driven by the engine also stops, and the oil pressure is not supplied to the transmission. Therefore, the oil pump operates when the engine is restarted. However, the increase in the hydraulic pressure of the transmission was delayed, and there was a possibility that the engine would run idle due to the delay in clutch engagement.

To prevent this, Japanese Patent Application Laid-Open No. 8-14076 discloses an accumulator or an electric hydraulic pump provided as a transmission hydraulic pressure holding / supplying means. The hydraulic pressure is continuously supplied to the automatic transmission even when the engine is stopped. There is disclosed a technique for preventing engine idling due to a delay in clutch engagement.

[0005]

[Problems to be solved by the invention]
In this conventional technique, although the engine can be prevented from idling, the hydraulic pressure is continuously supplied to the shift clutch and the valve group of the automatic transmission even when the engine is stopped. Considering the pressure drop due to leakage from the clutches and valve groups, it was inevitable to increase the size of the device.

Further, when an electric hydraulic pump is used as the transmission hydraulic pressure holding / supplying means, it is more expensive than an accumulator, and furthermore, electric power is consumed, so that the original effect of suppressing fuel consumption may be reduced.

SUMMARY OF THE INVENTION The present invention has been made in consideration of the above-described problems of the prior art, and has as its object to improve the mountability of the apparatus in an idle-stopped vehicle while preventing the engine from idling when the engine is restarted. And

[0008]

A first aspect of the present invention is a hydraulic pressure source driven by an engine, and a transmission hydraulic pressure holding / supply that can hold the hydraulic pressure from the hydraulic source and supply the hydraulic pressure to the transmission. Means for supplying a hydraulic pressure held by the transmission hydraulic pressure holding / supplying means to the transmission when the engine is restarted, in an idle stop vehicle which automatically stops and restarts the engine under predetermined operating conditions, the transmission comprising: Means for starting the rotation of the engine after a lapse of a predetermined time from the start of the supply of the hydraulic pressure from the hydraulic pressure holding and supplying means.

In a second aspect based on the first aspect, there is provided means for detecting a hydraulic pressure and an oil temperature of the transmission hydraulic pressure holding / supplying means. It is characterized in that it is set based on the temperature.

A third aspect of the present invention includes a hydraulic pressure source driven by an engine, and a transmission hydraulic pressure holding / supplying means capable of holding the hydraulic pressure from the hydraulic pressure source and supplying the hydraulic pressure to the transmission. Automatic stop of the engine under operating conditions,
In an idle-stop vehicle that performs automatic restart, a means for detecting the hydraulic pressure of the transmission, a means for supplying the hydraulic pressure held in the transmission hydraulic pressure holding / supplying means to the transmission when the engine is restarted, and a detected hydraulic pressure of the transmission And means for starting the rotation of the engine after the value has become equal to or more than a predetermined value.

A fourth aspect of the present invention includes a hydraulic pressure source driven by the engine, and a transmission hydraulic pressure holding / supplying means capable of holding the hydraulic pressure from the hydraulic pressure source and supplying the hydraulic pressure to the transmission. Automatic stop of the engine under operating conditions,
Means for detecting the oil pressure of the transmission oil pressure holding and supplying means in an idle stop vehicle performing automatic restart, and means for inhibiting automatic stop of the engine when the detected oil pressure of the transmission oil pressure holding and supplying means is equal to or lower than a predetermined pressure. And characterized in that:

According to a fifth aspect of the present invention, as the predetermined pressure in the fourth aspect, a pressure drop due to leakage from the transmission hydraulic pressure holding / supplying means is added to a hydraulic pressure value capable of transmitting a torque input to the transmission when the engine is restarted. It is characterized in that a set value is set.

In a sixth aspect based on the fifth aspect, there is provided means for detecting the oil pressure and the oil temperature of the transmission hydraulic pressure holding / supplying means, and a pressure drop due to leakage from the transmission hydraulic pressure holding / supplying means is detected. The calculation is performed based on the oil pressure and the oil temperature of the oil pressure holding / supplying means.

A seventh aspect of the present invention includes a hydraulic pressure source driven by an engine, and a transmission hydraulic pressure holding / supplying means capable of holding the hydraulic pressure from the hydraulic pressure source and supplying the hydraulic pressure to the transmission. Automatic stop of the engine under operating conditions,
In an idle stop vehicle that performs an automatic restart, a means for detecting the hydraulic pressure of the transmission hydraulic pressure holding / supplying means, and an engine when the detected hydraulic pressure of the transmission hydraulic pressure holding / supplying means drops below a predetermined pressure during automatic stop of the engine. Automatically restarting the device.

An eighth aspect of the present invention is characterized in that, as the predetermined pressure in the seventh aspect, a hydraulic pressure value capable of transmitting a torque input to the transmission when the engine is restarted is set.

A ninth invention is characterized in that in the first to eighth inventions, the supply destination of the hydraulic pressure from the transmission hydraulic pressure holding / supplying means is limited to elements required for starting the vehicle in the transmission. I do.

[0017]

According to the first aspect of the present invention, when the driver automatically releases the engine by releasing the brake pedal while the engine is idling, first, the transmission hydraulic pressure holding / supplying means changes the speed. Supply of hydraulic pressure to the machine starts. Then, after a lapse of a predetermined time from the start of supply of hydraulic pressure to the transmission, engine rotation is started.

Therefore, when the engine speed rises, the hydraulic pressure has already spread to the transmission, and there is no possibility that the power transmission element will not be poorly engaged due to a delay in raising the hydraulic pressure.
It is possible to prevent a sense of incongruity at the time of re-starting such as engine idling.
Further, unlike the related art, it is not necessary to continuously supply the hydraulic pressure to the transmission even when the engine is stopped, so that the device can be downsized and the mountability to the vehicle is not impaired.

The time from the start of supply of hydraulic pressure to the transmission to the transmission of hydraulic pressure to the power transmission element of the transmission varies depending on the hydraulic pressure and oil temperature of the transmission hydraulic pressure holding and supply means.
According to the second aspect, the time until the engine speed rises is set based on the oil pressure and the oil temperature of the transmission oil pressure holding / supplying means, so that the engine speed can be started at an appropriate time.

According to the third aspect of the invention, when the engine is restarted from the idle stop state, first, the hydraulic pressure is supplied to the transmission from the transmission hydraulic pressure holding / supplying means, and the hydraulic pressure of the transmission becomes a predetermined value or more. After that, the engine rotation is started. This can also reliably prevent poor engagement of the power transmission element.

According to the fourth and fifth aspects of the present invention, even when the vehicle is stopped due to a signal or the like, the hydraulic pressure of the transmission hydraulic pressure holding / supplying means is input to the transmission below a predetermined pressure, for example, when the engine is restarted. Automatic stop of the engine is prohibited if the pressure is equal to or less than a value obtained by adding a pressure drop due to leakage from the transmission hydraulic pressure holding means to a hydraulic pressure value capable of transmitting torque. Thus, it is possible to avoid a situation in which the engine is automatically stopped in a state where sufficient hydraulic pressure is not stored in the transmission hydraulic pressure holding / supplying means, and a sufficient hydraulic pressure is not supplied to the transmission when the engine is restarted.

The pressure drop due to leakage from the transmission hydraulic pressure holding / supplying means changes depending on the hydraulic pressure and oil temperature.
According to the sixth aspect, the pressure drop due to the leakage is set based on the oil pressure and the oil temperature of the transmission oil pressure holding / supplying means, so that the oil pressure required at the time of restart can be accurately obtained.

According to the seventh and eighth aspects of the present invention, the hydraulic pressure of the transmission hydraulic pressure holding / supplying means is equal to or less than a predetermined pressure even during idle stop, for example, the input to the transmission based on the target engine speed at startup. When the oil pressure becomes equal to or less than the hydraulic pressure value at which torque can be transmitted, the engine is automatically started. As a result, it is possible to prevent the oil pressure stored in the transmission oil pressure holding / supplying means from dropping below the oil pressure required to engage the power transmission element at the time of restart.

According to the ninth aspect of the present invention, the supply destination of the hydraulic pressure from the transmission hydraulic pressure holding / supplying means is limited to the elements necessary for restarting the engine and starting the vehicle in the transmission. Can be minimized. This allows
The transmission hydraulic pressure holding / supplying means can be reduced, and the mountability on the vehicle is improved.

[0025]

Embodiments of the present invention will be described below with reference to the accompanying drawings.

First, the configuration of an idle stop vehicle to which the present invention is applied and the hydraulic control circuit thereof will be described with reference to FIGS. 1 to 4, and thereafter, in the idle stop vehicle with reference to FIGS. The details of the engine automatic stop / start control that is performed will be described.

FIG. 1 shows a schematic configuration of an idle stop vehicle to which the present invention is applied, and FIGS. 2 and 3 show a continuously variable transmission 17 thereof.
1 shows a schematic configuration of a hydraulic control circuit 101 of FIG.

This idle-stop vehicle includes the engine 1 and the continuously variable transmission 17, and the controller 7 controls these based on signals from various sensors (not shown). In particular, when a predetermined condition is satisfied when the vehicle is stopped such as at a traffic light, the controller 7 automatically stops and restarts the engine 1.

A torque converter 10 and a forward / reverse switching mechanism 11 are interposed between the engine 1 and the continuously variable transmission 17. A hydraulic pump 14 is connected to the input shaft of the torque converter 10 as a hydraulic pressure source, and the hydraulic pressure generated by the hydraulic pump 14 is supplied to a hydraulic control circuit 101.
The forward / reverse switching mechanism 11 mainly includes a planetary gear mechanism 19, and switches the rotation direction of the input shaft 15 by selectively engaging the forward clutch 12 and the reverse clutch 13 driven by the hydraulic control circuit 101. Can be.

Here, the continuously variable transmission 17 is a so-called V-belt type continuously variable transmission composed of a primary pulley 16, a secondary pulley 26, and a V-belt 24 wound around them.

As shown in FIG. 2, the primary pulley 16
Is a fixed conical plate 18 which rotates integrally with the input shaft 15.
And a movable conical plate 22 which is disposed opposite to the V-shaped pulley groove and is displaceable in the axial direction of the input shaft 15 by hydraulic pressure acting on the primary pulley cylinder chamber 20. Similarly, the secondary pulley 26
Is a fixed conical plate 30 that rotates integrally with the driven shaft 28.
And a movable conical plate 34 which is disposed opposite to the V-shaped pulley groove and is displaceable in the axial direction of the driven shaft 28 according to the hydraulic pressure acting on the secondary pulley cylinder chamber 32.

Returning to FIG. 1, a drive gear 46 meshing with the idler gear 48 is fixed to the driven shaft 28.
The pinion gear 54 provided on the idler shaft 52 of No. 8 meshes with the final gear 55. The final gear 55 drives the drive shaft 57 via the differential device 56.

At the time of driving force transmission as described above, the hydraulic pressure in the primary pulley cylinder chamber 20 and the secondary pulley cylinder chamber 32 is controlled so that the movable conical plate 22 of the primary pulley 16 and the movable conical plate 34 of the secondary pulley 26 are pivoted. By changing the contact radius of the continuously variable transmission 17 by changing the contact radius with the V-belt 24, the speed ratio of the continuously variable transmission 17 can be changed.

For example, if the width of the pulley groove of the primary pulley 16 is increased, the contact radius of the V-belt 24 on the secondary pulley 26 side becomes relatively large, and a large speed ratio (Low side) can be obtained. Conversely, the primary pulley 16
If the width of the pulley groove is reduced, a small gear ratio (Hi side) can be obtained.

The control of the pulley groove widths of the primary pulley 16 and the secondary pulley 26 is performed by controlling the primary pulley cylinder chamber 20 and the secondary pulley cylinder chamber 3.
This is done by controlling the oil pressure to 2. Specifically, the control is performed by the controller 7 controlling the step motor 64 of the hydraulic control circuit 101 shown in FIG.
3 is controlled to adjust the hydraulic pressure supplied to the cylinder chamber 20 of the primary pulley 16 and the cylinder chamber 32 of the secondary pulley 26, thereby controlling the speed ratio of the continuously variable transmission 17.

The duty ratio of the line pressure solenoid 74 is controlled by the controller 7, and the pilot valve 61,
The line pressure control valve 60 is driven via the pressure modifier valve 62. The hydraulic pressure from the hydraulic pump 14 driven by the engine 1 is set to a predetermined line pressure and supplied to the line pressure circuit 40.
A predetermined oil pressure is supplied to the 0 clutch pressure circuit 41. The cylinder chamber 32 of the secondary pulley 26 communicates with the line pressure circuit 40.

Further, the clutch pressure circuit 41 connected downstream of the line pressure control valve 60 has a port 107b of a manual valve 107 responsive to the shift lever 81 via a check valve 108, as shown in FIG. Port 10 according to the position of the spool 107s of the manual valve 107
The hydraulic pressure is supplied to the forward clutch 12 or the reverse clutch 13 via the port 7a or the port 107b.

That is, when the shift lever 81 is in the forward position such as the D range, the ports 107b and 107a communicate with each other, and the hydraulic pressure of the clutch pressure circuit 41 is supplied to the forward clutch 12 to be engaged, while the port 107c is connected to the drain port. The reverse clutch 13 is released in communication with 107d.
If the shift lever 81 is in the reverse position of the R range, the port 107b and the port 107c communicate with each other, the hydraulic pressure of the clutch pressure circuit 41 is supplied to the reverse clutch 13 and the port 107a is connected to the drain side (in the drawing). Upper ×
And the forward clutch is released.

The above configuration is disclosed in Japanese Patent Application Laid-Open No.
This is almost the same as the hydraulic control circuit disclosed in Japanese Patent No. 2855, but in the present embodiment, the hydraulic pressure from the hydraulic pump 14 is further maintained, and the hydraulic pressure held in response to the hydraulic pressure supply command from the controller 7 is continuously variable. A transmission hydraulic pressure holding / supply circuit 9 that can supply power to the power transmission element (forward clutch 12 or reverse clutch 13) of the transmission 17 is provided. The check valve 108 of the clutch pressure circuit 41
A hydraulic supply circuit 42 for guiding the hydraulic pressure from the transmission hydraulic pressure holding and supply circuit 9 is provided between the check valve 1 and the manual valve 107.
09.

The check valve 108 regulates the flow of the hydraulic pressure from the hydraulic pressure supply circuit 42 to the line pressure control valve 60 side, and controls the hydraulic pressure from the transmission hydraulic pressure holding / supply circuit 9 to the manual valve 107.
The check valve 109 restricts the hydraulic pressure from the line pressure control valve 60 from flowing into the transmission hydraulic pressure holding / supplying circuit 9 during the operation of the engine 1.

The configuration of the transmission hydraulic pressure holding / supplying circuit 9 will be described in detail with reference to FIG.

As shown in FIG. 4, the line pressure circuit 40 of the hydraulic control circuit 101 includes a secondary pulley cylinder chamber 3
A shutoff valve 120 is interposed between the hydraulic pump 2 and the hydraulic pump 14, and a hydraulic pressure supply circuit 42 is disposed between the shutoff valve 120 and the secondary pulley cylinder chamber 32 via a check valve 121.

As described above, the continuously variable transmission 17 transmits power by the contact friction force between the primary pulley 16, the secondary pulley 26 and the V-belt 24. Therefore, when the engine 1 is stopped and no line pressure is generated, the If the hydraulic pressure in the cylinder chamber 32 is released, the driving force cannot be transmitted until the hydraulic pressure in the secondary pulley cylinder chamber 32 increases when the engine is restarted.

Therefore, when the line pressure becomes equal to or lower than a predetermined value, the shut-off valve 120 shuts off the secondary pulley hydraulic chamber 32 and the hydraulic pump 14, and when the hydraulic pressure in the secondary pulley cylinder chamber 32 becomes lower than the set pressure of the pressure reducing valve 117. The check valve 121 is opened, and hydraulic pressure is supplied from the transmission hydraulic pressure holding / supplying circuit 9 to the secondary pulley cylinder chamber 32.

The transmission hydraulic pressure holding / supplying circuit 9 is connected to an accumulator 115 via a pressure accumulation control valve 112 and a check valve 114.
Is provided, and the hydraulic pressure held by the hydraulic pump is supplied to the pressure reducing valve 117.
The downstream of the pressure reducing valve 117 communicates with the hydraulic pressure supply circuit 42.

The pressure-accumulation adjusting valve 112 communicates with the hydraulic pressure (line pressure) from the hydraulic pump 14 at a predetermined value, for example, below the accumulator maximum pressure, and supplies the hydraulic pressure to the accumulator 115 via the check valve 114, When the pressure exceeds a predetermined value, the oil pressure from the hydraulic pump to the accumulator 115 is shut off to minimize energy loss for accumulating pressure.

The pressure reducing valve 117 supplies the hydraulic pressure supplied to the hydraulic pressure supply circuit 42 to the forward clutch 12 or the reverse clutch 1.
3 is immediately before the engagement (for example, about 0.3 mm).
The pressure is reduced to 2 MPa).

A relief valve 113, a hydraulic pressure sensor 116 and an oil temperature sensor 111 are provided between the check valve 114 and the pressure reducing valve 117. The relief valve 113 is the check valve 11
It operates so that the oil pressure between the pressure reducing valve 4 and the pressure reducing valve 117 does not exceed a predetermined value, for example, the accumulator maximum pressure. The pressure sensor 116 and the oil temperature sensor 111 are an accumulator 115
And is used for engine automatic stop / start control described later.

Further, in this embodiment, when the engine is restarted, the hydraulic pressure of the power transmission element of the continuously variable transmission 17 is raised between the check valve 114 and the pressure reducing valve 117 so as to rise before the engine rotation starts. A pilot pressure circuit 119 communicating with the spring chamber side of the pressure reducing valve 117 is provided, and a three-way solenoid valve 118 controlled by the controller 7 is interposed in the pilot pressure circuit 119.

The three-way solenoid valve 118 is connected to the controller 7
Switching between supplying the hydraulic pressure downstream of the check valve 114 to the spring chamber side of the pressure reducing valve 117 and the drain state in accordance with a command from the control valve, and changing the hydraulic pressure downstream of the check valve 114 to the spring chamber side. The check valve 117 becomes a simple switching valve, and the set pressure of the relief valve 113 or the hydraulic pressure of the accumulator 115 is supplied to the power transmission element (such as the forward clutch 12) via the hydraulic supply circuit 42. In addition,
When the spring chamber is in the drain state, the hydraulic pressure reduced according to the set pressure of the spring is applied to the hydraulic supply circuit 42.
Supplied to

Subsequently, referring to FIGS. 5 to 12,
The content of the engine automatic stop start control performed in the idle stop vehicle having the above configuration, the processing at the time of engine restart,
The process for determining whether to stop the engine and the process for determining whether to restart the engine will be described separately.

First, the processing performed when the engine is restarted, that is, when the engine is restarted from the idle stop state, will be described.

FIG. 5 shows the contents of the processing at that time. First, at step S11, it is determined whether or not an automatic engine start command has been issued. Here, the engine automatic start command is a command issued when a predetermined condition (eg, brake pedal ON → OFF) is satisfied during idle stop. When it is determined that the engine automatic start command has been issued, the process proceeds to step S12, and otherwise, the process remains at step S11. At this time, only the engine automatic start command has been issued, and the engine 1 has not started yet.

In step S12, the pressure sensor 116,
Based on the output from the oil temperature sensor 111, the check valve 114 and the pressure reducing valve 117 of the transmission
During this time, the hydraulic pressure and oil temperature of the hydraulic circuit are detected.

In step S13, based on the oil pressure and oil temperature of the supply source detected in step S12, a standby time until the rotation of the engine 1 is started is set with reference to map data as shown in FIG. It is considered that the higher the oil pressure and the oil temperature, the more quickly the oil pressure reaches the supply destination. Therefore, the standby time is set shorter as the oil pressure is higher and the oil temperature is higher.

In step S14, a hydraulic pressure supply command is issued to the transmission hydraulic pressure holding / supplying circuit 9, and the supply of hydraulic pressure to the power transmission element (such as the forward clutch 12) of the automatic transmission 17 is started. Specifically, the three-way solenoid valve 118 is driven,
Set pressure of relief valve 113 or accumulator 115
Is supplied to the hydraulic pressure supply circuit 42.

In step S15, the measurement of the elapsed time t from the issuance of the hydraulic pressure supply command is started.
At 16, it is determined whether or not the elapsed time t has become equal to or longer than the standby time set in step S13. When the standby time has elapsed, the process proceeds to step S17, and otherwise, the process remains at step S16.

In step S17, an engine rotation start command is issued. Specifically, power is supplied to an engine starting motor, for example, a starter motor, and the engine 1 is started.

Therefore, by processing the above flow, if the driver issues an automatic engine start command by releasing the brake pedal or the like during idling stop, the transmission hydraulic pressure holding supply circuit 9 The hydraulic pressure supply to the step transmission 17 is started. Then, after a lapse of a predetermined time from the start of the supply of the hydraulic pressure, a rotation start command of the engine 1 is issued. Thus, the continuously variable transmission 1
Since the hydraulic pressure of the engine 7 is started in advance, when the rotation start command of the engine 1 is issued, sufficient hydraulic pressure has already been supplied to the power transmission elements (such as the forward clutch 12) necessary for starting. Thus, there is no possibility that the engine 1 will be idlely blown due to the clutch engagement failure.

Unlike the prior art, the hydraulic pressure is not continuously supplied to the transmission even when the engine 1 is stopped, and the hydraulic pressure is supplied only to the forward clutch 12 and the like necessary for starting the vehicle. Leak flow during shutdown can be minimized. Thereby, the pressure accumulating element such as the accumulator 115 can be reduced in size, and the mountability on the vehicle is improved.

Further, the response time of the hydraulic pressure supply varies depending on the hydraulic pressure and the oil temperature of the supply source. In the present embodiment, since the standby time is set using these parameters as parameters, the minimum standby time until the engine rotation starts is minimized. Time can be set. As a result, the start-up delay of the engine rotation is minimized, and the starting feeling can be improved.

FIG. 7 shows how the supply hydraulic pressure and the engine speed change when the engine is restarted. As described above, the engine rotation start command is issued after a predetermined time has elapsed after the start of the supply of the hydraulic pressure, so that the idling of the engine due to the poor clutch engagement is reliably prevented.

Here, the engine rotation start command is issued after a lapse of a predetermined time from the issuance of the hydraulic pressure supply command. However, as shown in FIG. 8, the hydraulic pressure of the supply destination is detected (step S23), and this is detected. The engine rotation start command may be issued after the oil pressure becomes equal to or more than a predetermined oil pressure, for example, oil pressure at which torque input to the automatic transmission 17 can be transmitted without restarting the clutch when the engine is restarted (step S2).
4, S25).

FIG. 9 shows how the supply hydraulic pressure and the engine speed change when the engine is restarted in this case. By issuing the engine rotation start command after the oil pressure of the supply destination actually rises to the predetermined value in this way, it is possible to reliably prevent the engine rotation from starting in a state of clutch engagement failure.

Next, a description will be given of an engine stop permission determining process, that is, a process of determining whether to permit an idle stop when the vehicle is stopped at a traffic light or the like.

FIG. 10 shows the content of the process for determining whether to stop the engine. First, in step S31, it is determined whether or not the engine is rotating (during normal operation). If it is determined that the engine is running, step S32
Otherwise, the process remains in step S31.

In step S32, the condition for stopping the engine is
For example, it is determined whether conditions such as zero vehicle speed and brake pedal ON are satisfied. If the condition is satisfied, the process proceeds to step S33; otherwise, the process proceeds to step S32.
Stay in.

In step S33, the hydraulic pressure and oil temperature of the hydraulic circuit section between the check valve 114 and the pressure reducing valve 117 of the transmission hydraulic pressure holding / supplying circuit 9, which is the supply source, are detected. In step S34, the detection is performed in step S33. The amount of pressure drop due to leakage is calculated based on the oil pressure and oil temperature. Here, the pressure drop due to leakage is calculated by referring to map data as shown in FIG. 11, and a larger value is calculated as the pressure of the supply source is higher and the oil temperature of the supply source is higher.

In step S35, the oil pressure of the supply source exceeds a predetermined pressure, for example, a value obtained by adding the pressure drop due to the leak to the oil pressure required to transmit the torque input to the continuously variable transmission 17 when the engine is restarted. It is determined whether or not the engine has stopped, and if not, the process proceeds to step S36, and the automatic stop of the engine is prohibited.

Therefore, by processing this flow, even if the vehicle is stopped due to a signal or the like, the automatic stop of the engine is prohibited if the hydraulic pressure required for restarting is not secured. Become. In addition, in order to perform restart without causing clutch engagement failure, the above-mentioned required oil pressure is set in consideration of a decrease in oil pressure due to leakage occurring during the stop period. Is set to a large value. Thus, it is possible to prevent the stop of the engine from stopping in a state in which sufficient hydraulic pressure is not stored in the transmission hydraulic pressure holding / supplying circuit 9, which is a supply source, and to engage the power transmission element due to insufficient hydraulic pressure when the engine is restarted. Failure can be prevented.

Further, the pressure drop due to the leak varies depending on the oil pressure and the oil temperature of the supply source. Since the pressure drop due to the leak is calculated by referring to the map data using the oil pressure and the oil temperature of the supply source as parameters, the oil temperature The optimal judgment can be made even when the value changes.

In this case, the required oil pressure at the time of restart is set to a value obtained by adding the pressure drop due to leakage to the oil pressure required to transmit the torque input to the continuously variable transmission 17 at the time of engine restart. However, a similar effect can be obtained by simplifying this and setting the maximum pressure of the accumulator.

Next, a description will be given of an engine restart determination process, that is, a process of determining whether or not to restart the engine when idling is stopped.

FIG. 12 is a flowchart showing the contents of the engine restart determination processing. First, in step S41, it is determined whether or not the engine is stopped. If the engine is stopped, step S42 is performed. Proceed to.

In step S42, it is determined whether or not conditions for restarting the engine, for example, conditions such as brake pedal ON → OFF, are satisfied. If the conditions are satisfied, the flow advances to step S44 to issue an engine automatic start command. Is issued, and if the condition is not satisfied, the process proceeds to step S43.

In step S43, the hydraulic pressure in the hydraulic circuit between the check valve 114 and the pressure reducing valve 117, which is the supply source, is less than a predetermined pressure, for example, the torque input to the transmission according to the target engine speed at startup is transmitted. It is determined whether the oil pressure is equal to or less than a possible oil pressure value. If the oil pressure is equal to or less than the predetermined pressure, the process proceeds to step S44 to issue an engine automatic start command. Note that the median of the maximum pressure and the minimum pressure of the accumulator may be set as the predetermined pressure.

Therefore, by processing this flow, if the hydraulic pressure of the transmission hydraulic pressure holding / supplying circuit 9 drops to near the required hydraulic pressure at the time of restart due to leakage or the like while the engine is stopped, other restart conditions Is not satisfied, an engine automatic start command is issued. As a result, poor engagement of the power transmission element at the time of restarting the engine due to insufficient supply pressure can be prevented, and the reliability of the idle stopped vehicle can be improved.

When the engine 1 is automatically started due to a decrease in oil pressure, the engine 1 is started regardless of the driver's intention to start. Good.

Although the embodiments of the present invention have been described above, the scope of application of the present invention is not limited to this, and it can be widely applied to any idling stop vehicle provided with transmission hydraulic pressure holding / supplying means. Things.

[Brief description of the drawings]

FIG. 1 is a schematic configuration diagram of an idle stop vehicle to which the present invention is applied.

FIG. 2 is a schematic configuration diagram of a hydraulic control circuit of the continuously variable transmission.

FIG. 3 is a schematic configuration diagram of a hydraulic control circuit of the continuously variable transmission.

FIG. 4 is a schematic configuration diagram of a transmission hydraulic pressure holding supply circuit.

FIG. 5 is a flowchart for explaining a process when the engine is restarted.

FIG. 6 is a map for setting a standby time until the engine speed is increased based on the oil pressure and the oil temperature of the supply source.

FIG. 7 is a timing chart showing how supply hydraulic pressure and engine speed change when the engine is restarted.

FIG. 8 is a flowchart for explaining another example of the process at the time of restarting the engine.

FIG. 9 is a timing chart showing changes in supply hydraulic pressure and engine speed when the engine is restarted in that case.

FIG. 10 is a flowchart illustrating a process of determining whether to stop the engine.

FIG. 11 is a map for calculating a pressure drop due to leakage based on the oil pressure and the oil temperature of the supply source.

FIG. 12 is a flowchart illustrating a process of engine restart determination.

[Explanation of symbols]

 1 Engine 7 Controller 9 Transmission Hydraulic Holding Supply Circuit 12 Forward Clutch 13 Reverse Clutch 17 Continuously Variable Transmission 42 Hydraulic Supply Circuit 101 Hydraulic Control Circuit 107 Manual Valve 111 Oil Temperature Sensor 116 Pressure Sensor 115 Accumulator

 ──────────────────────────────────────────────────続 き Continued on the front page F term (reference) 3G092 AC03 BA03 CA01 DF04 DG05 EA01 EA09 EA16 EA17 FA32 FA50 GA01 GA04 GA10 HE01Z HF11Z HF19Z HF20Z 3G093 AA05 AB00 BA21 BA22 BA28 CA00 CA01 CA02 CA04 DB07 FB03 EB03 FB03

Claims (9)

[Claims] An oil pressure source driven by an engine; and a transmission oil pressure holding / supplying means capable of holding the oil pressure from the oil pressure source and supplying the oil pressure to the transmission.
Means for supplying a hydraulic pressure held by the transmission hydraulic pressure holding / supplying means to the transmission when the engine is restarted, in an idle stop vehicle that automatically stops and restarts the engine under predetermined operating conditions; Means for starting rotation of the engine after a lapse of a predetermined time from the start of supply of hydraulic pressure from the means. 2. The apparatus according to claim 1, further comprising means for detecting a hydraulic pressure and an oil temperature of the transmission hydraulic pressure holding / supplying means, wherein the predetermined time is set based on the detected hydraulic pressure and oil temperature of the transmission hydraulic pressure holding / supplying means. The idle-stop vehicle according to claim 1, wherein: 3. A hydraulic pressure source driven by an engine, and a transmission hydraulic pressure holding / supplying means capable of holding a hydraulic pressure from the hydraulic pressure source and supplying the hydraulic pressure to the transmission,
In an idle stop vehicle that automatically stops and restarts an engine under predetermined operating conditions, a means for detecting the hydraulic pressure of the transmission, and a hydraulic pressure held by the transmission hydraulic pressure holding / supplying means when the engine is restarted is transmitted to the transmission. An idle stop vehicle comprising: a supplying unit; and a unit configured to start rotation of the engine after a detected hydraulic pressure of the transmission becomes equal to or more than a predetermined value. 4. A hydraulic pressure source driven by an engine, and a transmission hydraulic pressure holding / supplying means capable of holding a hydraulic pressure from the hydraulic pressure source and supplying the hydraulic pressure to the transmission.
An idle stop vehicle that automatically stops and restarts the engine under predetermined operating conditions; Means for prohibiting automatic stop of the engine in the case of (i). 5. The control device according to claim 1, wherein the predetermined pressure is set to a value obtained by adding a pressure drop by a leak from the transmission hydraulic pressure holding / supplying means to a hydraulic pressure value capable of transmitting a torque input to the transmission when the engine is restarted. The idle stop vehicle according to claim 4, wherein the vehicle is stopped. 6. A transmission hydraulic pressure holding / supplying means for detecting a hydraulic pressure and an oil temperature of the transmission hydraulic pressure holding / supplying means. The idle stop vehicle according to claim 5, wherein the calculation is performed based on the oil temperature. 7. A hydraulic pressure source driven by an engine, and a transmission hydraulic pressure holding / supplying means capable of holding a hydraulic pressure from the hydraulic pressure source and supplying the hydraulic pressure to the transmission.
In an idle stop vehicle that automatically stops and automatically restarts an engine under predetermined operating conditions, a means for detecting a hydraulic pressure of the transmission hydraulic pressure holding / supplying means, and a transmission hydraulic pressure holding / supplying means detected while the engine is automatically stopped. Means for automatically restarting the engine when the oil pressure drops below a predetermined pressure. 8. The idle stop vehicle according to claim 7, wherein the predetermined pressure is set to a hydraulic pressure value capable of transmitting a torque input to the transmission when the engine is restarted. 9. The transmission according to claim 1, wherein a supply destination of the hydraulic pressure from the transmission hydraulic pressure holding / supplying means is limited to an element required for starting the vehicle in the transmission. The idle stop vehicle according to one of the above.