JPH0814076A - Automatic engine stop/starting device - Google Patents

Abstract

PURPOSE:To prevent the generation of a shock during engagement of the clutch of a hydraulic automatic transmission during the starting of an automatic stop starting type engine. CONSTITUTION:Even when an engine is stopped through automatic stop processing at a cross and the feed of an oil pressure by an oil pump 51 is brought into a stop, the oil pressure of an AT hydraulic unit 53 is maintained by a check valve 63 and an accumulator 65. Thus, before the restarting of the engine, an automatic transmission 9 is brought into a shift for starting. Since, as noted above, the clutch of the automatic transmission 9 is engaged in a shift state for a start before the starting of the engine, when the engine is restarted, the generation of a shock when the clutch of the automatic transmission 9 is engaged is prevented from occurring.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an automatic stop and start device for saving fuel and improving exhaust emission by executing automatic stop and automatic start of an engine at an intersection or the like, and more particularly to a hydraulic automatic shift. TECHNICAL FIELD The present invention relates to an engine automatic stop and start device used in a vehicle equipped with a machine.

[0002]

2. Description of the Related Art Conventionally, when an automobile stops at an intersection or the like while driving in an urban area, the engine is automatically stopped under a predetermined stop condition, and then the engine is restarted under a predetermined start condition so that the fuel is saved. Automatic stop and start devices are known to save and improve exhaust emissions. As such a device, for example, JP-A-60-125738.
No. In order to prevent the vehicle from starting to move due to a creep phenomenon when the automatic transmission is used together with the automatic stop / start device, the high speed gear is selected as the automatic transmission when the engine is stopped. Therefore, the engine is started in the high-speed gear state, the creep phenomenon can be prevented, and thereafter, the low-speed gear is switched to enable the vehicle to start.

[0003]

However, when the automatic transmission is a hydraulic automatic transmission, the oil pump (hydraulic pump) that generates hydraulic pressure by the driving force of the engine also stops when the engine is stopped. As a result, the hydraulic pressure for operating the automatic transmission naturally drops. Therefore, the engagement state of the clutch that switches the shift state of the automatic transmission by hydraulic pressure is also released.

When the engine start condition is satisfied by depressing the accelerator pedal in this state, the engine starts and starts to rotate, and the discharge pressure of the oil pump of the automatic transmission gradually rises. When a sufficient hydraulic pressure is obtained, the clutch is reengaged and the vehicle enters the first speed, for example. However, at this time, the engine was running at a high speed, so a shock was generated when the clutch was engaged, resulting in discomfort to the driver.

An object of the present invention is to prevent the above-mentioned shock of the hydraulic automatic transmission at the time of starting the engine.

[0006]

According to the first aspect of the present invention,
An automatic engine stop / start device for use in a vehicle equipped with a hydraulic automatic transmission capable of switching to various shifts using hydraulic pressure from a hydraulic source that generates hydraulic pressure as a result of driving the engine. When the oil pressure maintaining means that maintains the engine even when the engine is stopped, the sensor group that detects the states of the engine and each part of the vehicle, and the engine stop condition that does not depend on the operation of the ignition key are satisfied based on the detection signals from the sensor group. The engine stopping means for stopping the engine, the engine restarting means for restarting the engine when the engine starting condition is satisfied based on the detection signal from the sensor group without operating the ignition key, and the engine stopping means. After stopping the engine and before restarting the engine by the engine restarting means, the hydraulic A stop process unit that the dynamic transmission to the starting shift, an engine automatic stop and start device characterized by comprising a.

The invention according to claim 2 is the engine automatic stop / start device according to claim 1, wherein the hydraulic pressure maintaining means is means for maintaining the operating hydraulic pressure of the clutch hydraulic unit of the hydraulic automatic transmission. According to a third aspect of the present invention, the hydraulic pressure maintaining means does not depend on the driving force of the engine by the check valve for preventing the reverse flow of oil from the clutch hydraulic unit to the hydraulic power source side. 3. The automatic engine stop and start device according to claim 2, further comprising a hydraulic pressure supply unit that supplies hydraulic pressure to the.

According to a fourth aspect of the invention, there is provided the engine automatic stop / start device according to the third aspect, wherein the hydraulic pressure supply means is an accumulator. The invention according to claim 5 is the automatic engine stop and start device according to claim 3, wherein the hydraulic pressure supply means is an electric hydraulic pump that uses a battery as a power source.

According to a sixth aspect of the present invention, based on an on-off valve capable of releasing the working hydraulic pressure when opened, and a detection signal from the sensor group, an engine starting operation is performed by operating an ignition key under a predetermined condition. The automatic engine stop starter according to any one of claims 1 to 5, further comprising: residual pressure discharge means for temporarily opening the on-off valve when the above-mentioned operation is performed.

According to a seventh aspect of the invention, the sensor group is
In addition to the first detection means for detecting the rotation speed of the drive wheel and the second detection means for detecting the rotation speed of the engine,
7. The engine automatic stop according to claim 1, further comprising engine output control means for controlling the output of the engine based on the detected correspondence between the rotational speed of the drive wheel and the rotational speed of the engine. It is a starting device.

[0011]

According to the first aspect of the invention, the hydraulic pressure maintaining means maintains the hydraulic pressure for switching the shift of the hydraulic automatic transmission even when the engine is stopped. That is, while the engine is stopped, at least before the engine is restarted by the engine restarting means, the clutch engagement state of the hydraulic automatic transmission is maintained in the starting shift state by the stop time processing means. Therefore, when the engine is restarted, no shock occurs when the clutch is engaged.

The oil pressure maintaining means may maintain the oil pressure of the entire hydraulic automatic transmission, but may be any means for maintaining the operating oil pressure of the hydraulic unit for the clutch of the hydraulic automatic transmission. It is possible to prevent a shock due to the clutch engagement at the time. The hydraulic pressure maintaining means includes a check valve for preventing reverse flow of oil from the clutch hydraulic unit to the hydraulic pressure source side, and a hydraulic pressure supplying means for supplying hydraulic pressure to the clutch hydraulic unit without depending on the driving force of the engine. It may be The check valve does not release the hydraulic pressure from the hydraulic unit for the clutch, and the hydraulic pressure supply unit prevents the hydraulic pressure from decreasing due to leakage, and the clutch engagement is maintained even when the engine is stopped. The check valve and the hydraulic pressure supply means are provided, for example, in the hydraulic path from the hydraulic pressure source to the clutch hydraulic unit.

The hydraulic pressure supply means for supplying hydraulic pressure independently of the driving force of the engine may be an accumulator or an electric hydraulic pump using a battery as a power source. Since the accumulator uses the hydraulic pressure that has already accumulated, the operating hydraulic pressure can be maintained even if there is no engine driving force, and the clutch engagement can be maintained. In the case of an electric hydraulic pump that uses a battery as its power source, the hydraulic pump is operated by the battery that has already accumulated electrical energy, so the operating hydraulic pressure can be maintained even without engine driving force, and the clutch engagement can be maintained. it can.

Further, the automatic engine stop / starting device of each of the above-mentioned configurations further operates an ignition key under a predetermined condition based on an on-off valve capable of releasing the working oil pressure when opened and a detection signal from a sensor group. There may be provided residual pressure discharging means for temporarily opening the on-off valve when the engine is started. The oil pressure may be maintained at all times by the oil pressure maintaining means, but especially when the driver operates the ignition key to start the engine,
If the clutch of the automatic transmission is connected, the vehicle may move forward. Therefore, when the engine is started by operating the ignition key, it is desirable to remove the working hydraulic pressure by the residual pressure discharging means to start the engine. Because. In addition to this, when the driver turns off the ignition key to stop the engine, the residual hydraulic pressure discharging means may release the operating hydraulic pressure.

It is possible to prevent the forward movement of the vehicle by other means even if the operating hydraulic pressure is maintained without providing the opening / closing valve and the residual pressure discharging means. Is no problem. Furthermore, in the engine automatic stop / start device of each of the above configurations, the sensors of the sensor group include first detection means for detecting the rotation speed of the drive wheels and second detection means for detecting the rotation speed of the engine. In addition, if the engine output control means for controlling the output of the engine is further provided based on the detected correspondence between the rotational speed of the drive wheel and the rotational speed of the engine, the following action and effect can be further obtained. Occurs.

In this type of engine stop and start device, when the accelerator is rapidly depressed at the same time when the engine is restarted by the engine restarting means, the engine output greatly increases. Then, a large load may be applied to the power transmission system such as the torque converter or the transmission gear, or the drive wheels may idle. These phenomena may be obstacles in improving the durability of the power transmission system and reducing vehicle noise. However, it is known that the load applied to the power transmission system has a good correspondence relationship between the rotational speed of the drive wheels and the engine rotational speed, for example, the ratio of both rotational speeds.

Therefore, if the above-mentioned configuration is adopted, in addition to the above-mentioned actions and effects, the engine is prevented from being subjected to a large load on the power transmission system based on the correspondence between the rotational speed of the drive wheels and the rotational speed of the engine. Output can be suppressed. In this case, the durability of the power transmission system can be improved satisfactorily, and the drive wheels can be prevented from idling to reduce the vehicle noise satisfactorily.

[0018]

1 shows a system configuration diagram of a first embodiment of the present invention. The engine 1 is provided with an injector 3, a starter 5, and an igniter 7, and an automatic transmission 9 is connected to the output shaft of the engine 1. The automatic transmission 9 has solenoid valves 10a and 10b.
When a and 10b are turned on / off, a hydraulic circuit corresponding to each transmission gear position is formed and a predetermined gear position is selected.

An intake manifold 11 and an exhaust manifold 13 are connected to each cylinder of the engine 1, and the intake manifold 11 is provided with a throttle valve 15 interlocking with an accelerator pedal. In addition, a parking brake 17, a driver's seat display panel 19 and the like are provided in the vehicle.

The throttle valve 15 is provided with a throttle position sensor 15a for detecting its opening degree and an idle switch 15b for detecting a fully closed state. For the automatic transmission 9, a neutral range switch 21a that outputs a neutral range signal when the neutral range is selected, a parking range switch 21b that outputs a parking range signal when the parking range is selected, and a drive range are selected. Drive range switch 21 that outputs a drive range signal when operated
c, an L range switch 21d that outputs an L range signal when the L range is selected, and an S range switch 21e that outputs an S range signal when the S range is selected.
And a range switch group having an R range switch 21f that outputs an R range signal when the R range is selected, and a rotation speed of an output shaft (not shown) of the automatic transmission 9 connected to the propulsion shaft. A vehicle speed sensor 23 that detects the vehicle speed is provided.

The parking brake 17 is provided with a parking brake switch 25 which outputs a parking brake signal at the time of operation.
A display lamp 27 is provided to indicate that the vehicle is stopped and to notify the driver of various warnings described later. An ignition switch 20 that outputs a start signal when the engine is started is provided at a predetermined location.

The injector 3 is connected via the fuel relay 31, the starter 5 is connected via the starter relay 33, and the igniter 7 is connected via the ignition relay 35.
It is connected to the. Also, the solenoid valves 10a, 1
0b and the indicator lamp 27 are connected to the control circuit 37.

The control circuit 37 includes an ignition primary coil 7a of the igniter 7, a throttle position sensor 15a, an idle switch 15b, an ignition switch 20, a neutral range switch 21a, a parking range switch 21b, a drive range switch 21c, an L range switch 21d, S range switch 21e, R range switch 21f, vehicle speed sensor 23, parking brake switch 25, door switch 39a, light switch 39
b, an air conditioner switch 39c, a hydraulic switch 39d, a turn switch 39e, a water temperature sensor 39g, an intake air temperature sensor 39h, and an intake air amount sensor 39i are connected. Further, an electromagnetic opening / closing valve 67 provided in the automatic transmission 9 is connected to the control circuit 37 as described later.

FIG. 2 shows a detailed configuration example of the control circuit 37 shown in FIG. The control circuit 37 is a CP that controls various devices.
U37a, ROM37b in which various numerical values and programs are written in advance, RAM37c in which numerical values and flags in the arithmetic process are written in a predetermined area, A / D converter (ADC) 37 for converting an analog input signal into a digital signal
d. Input / output interface (I / O) 37 to which various digital signals are input and various digital signals are output
e, and a bus line 37f to which each of these devices is connected. The program shown in the flowchart described later is written in the ROM 37b in advance.

The I / O 37e has an idle switch 15b.
Idle signal from the ignition primary coil 7a, the engine speed signal from the ignition primary coil 7a, the start signal from the ignition switch 20, the neutral range signal from the neutral range switch 21a, the parking range switch 21.
parking range signal from b, drive range signal from drive range switch 21c, L range signal from L range switch 21d, S range signal from S range switch 21e, R range signal from R range switch 21f, parking brake switch Parking brake signal from 25, vehicle speed signal from vehicle speed sensor 23,
Door signal from door switch 39a, light switch 3
The light signal from 9b, the air conditioner signal from the air conditioner switch 39c, the hydraulic switch signal from the hydraulic switch 39d, the turn signal from the turn switch 39e, and the ignition signal from the ignition switch 20 are input, and the ADC 37d receives from the water temperature sensor 39g. , The intake air temperature signal from the intake air temperature sensor 39h, the intake air amount signal from the intake air amount sensor 39i, and the throttle position signal from the throttle position sensor 15a.
Then, the CPU 37a executes various calculations based on these various signals, and the ignition cut and ignition signals, the fuel cut and fuel injection signals, the starter drive signal, the drive signal of the display panel 19, the solenoid valve from the I / O 37e. The drive signals of 10a and 10b and the solenoid on-off valve 67
And the drive signal of.

Next, FIG. 3 shows a schematic block diagram of the automatic transmission 9. The automatic transmission 9 includes an oil pump (hydraulic pump) 51, an AT hydraulic unit 53, a primary regulator valve 55, a secondary regulator valve 57,
Each lubrication mechanism 59 and a torque converter 61 are provided.

The oil pump 51 serves as a hydraulic pressure source for the entire automatic transmission 9 and generates hydraulic pressure by the driving force of the engine 1. The AT hydraulic unit 53 corresponds to a clutch hydraulic unit, and includes a clutch group and a valve group that determine the shift of the automatic transmission 9. By switching the valve group based on the operating state of the engine 1, the oil pump 51 is operated. The supply destination of the hydraulic pressure from is switched to execute the predetermined clutch engagement / disengagement to realize the required shift state. The primary regulator valve 55 adjusts the hydraulic pressure supplied to each element of the automatic transmission 9 to a pressure suitable for the vehicle speed and the engine output, and supplies the hydraulic pressure to the secondary regulator valve 57 side. The secondary regulator valve 57 adjusts the converter pressure, the lubricating oil pressure, etc. to a pressure that matches the vehicle speed and the engine output, and supplies the torque converter 61 and each lubricating mechanism 59. Since the more detailed structure of the automatic transmission 9 is generally known, the description thereof will be omitted.

The features of the automatic transmission 9 are as follows. First, in the case where the check valve 63 is provided between the AT hydraulic unit 53 and the oil pump 51 in the hydraulic path 53a from the oil pump 51 to the AT hydraulic unit 53, and the oil pump 51 is stopped when the engine is stopped, The backflow of oil to the oil pump 51 side is prevented. An accumulator 65 is provided between the check valve 63 and the AT hydraulic unit 53 to prevent the hydraulic pressure from decreasing due to leakage when the oil pump 51 is stopped.
The hydraulic pressure of the AT hydraulic unit 53 is maintained. Further, the electromagnetic opening / closing valve 6 is provided between the check valve 63 and the AT hydraulic unit 53.
7 is provided so that the hydraulic pressure of the AT hydraulic unit 53 can be released if necessary.

The operation of the engine automatic stop / start device configured as described above will be described. FIG. 4 shows a flowchart of the engine automatic stop processing executed by the control circuit 37. This processing is started by turning on the ignition switch 20 and supplying power to the control circuit 37, and is repeatedly executed.

First, based on the vehicle speed signal, it is determined whether the vehicle speed is 0, or strictly speaking, whether the vehicle speed is a predetermined value or less (step 8).
2), the engine speed N based on the engine speed signal
It is determined whether or not e is less than or equal to a predetermined idle speed (step 84), and it is determined based on the idle signal whether the idle switch 15b is on, that is, the throttle valve 15 is fully closed (step 86). Based on the parking brake signal, it is determined whether the parking brake 17 is operating (step 88), and the shift is D,
It is determined whether the range is L or S (step 89), and other stop conditions for automatically stopping the engine 1, for example, no turn signal is issued, and the headlamp is turned on. It is determined from the turn signal, the light signal, the air conditioner signal, the water temperature signal, etc. that the light is not lit, the air conditioner is not operating, and the water temperature is above a predetermined level (step 90).

If all of these steps 82 to 90 are affirmatively determined, the engine automatic stop condition is satisfied, and the I / O 37e outputs the fuel cut signal and the ignition cut signal which form the engine stop signal to the fuel relay 31, The engine 1 is stopped by outputting it to the ignition relays 35, thereby preventing a high voltage from being supplied from the igniter 7 to the ignition plug, and by not injecting fuel from the injector 3 (step 9).
2).

Note that, for example, when the fuel cut processing or the like is performed during deceleration before the vehicle is stopped, the engine 1 has already stopped, so that the processing of step 92 is not necessary and the fuel cut is performed as it is. It is sufficient to continue the ignition cut. Next, the engine starting process will be described based on the flowchart of FIG. This process is a process that is repeatedly executed when the ignition switch 20 is turned on and power is supplied to the control circuit 37.

First, it is determined whether the engine is in a stalled state (step 102), the idle switch 15b is turned off (step 104), and the shift range is one of D, L and S. Whether or not (step 106) is determined. If the affirmative judgment is made in all of the steps 102 to 106, it is judged that the driver who has stopped at the intersection or the like is stepping on the accelerator and is about to start the driving again, so the warning lamp display stop processing is performed (step 108). ), The automatic transmission 9 is fixed to the starting shift (usually the first speed or the second speed) (step 11
0), the starter 5 is driven to start the engine 1 (step 112). This causes the vehicle to start.

The state in which the idle switch 15b is off in step 104 is a process for detecting that the ignition switch 20 has not started. Of course, before the step 104, it may be possible to determine whether or not the ignition switch 20 is started, but normally, when the accelerator is stepped on, the ignition switch 20 is not turned to the starting state, so the ignition is determined in the step 104. It is determined that the start is not made by the switch 20.

In step 106, the shift range is D, L,
If it is not in one of the ranges S, the warning lamp of the display panel 19 is lit and displayed (step 114) and the driver is prompted to enter the range D, L or S. Next, it is determined whether or not the ignition switch 20 is in the starting state (step 116), but when the ignition switch 20 is stopped at an intersection or the like, normally, the ignition switch 20 is not in the starting state, that is, the starter drive signal is not output.
The processing is terminated as it is, and the processing from step 102 is repeated again.

On the other hand, even when the ignition switch 20 is turned on and is started by the ignition switch 20, the engine 1 is stopped, so that the step 102 is performed.
Is affirmatively determined. However, since the idle switch 15b is in the ON state at such a start, step 10
At 4, a negative decision is made. Next, it is determined whether the shift range is in the range P or N (step 120). If not, there is a risk of moving forward when the engine 1 is started. Therefore, it is indicated by a warning lamp that it is necessary to set the range to either P or N (step 122), and the process is temporarily terminated.

If the shift range is in either the P or N range and the determination in step 120 is affirmative, it is determined whether or not the ignition switch 20 is in the starting state (step 116), and the ignition switch is turned on. If the engine has not been started at 20, the processing is ended as it is, and the engine is not started. If the ignition switch 20 is about to be started, an affirmative decision is made in step 116, the electromagnetic opening / closing valve 67 is then opened, and the hydraulic pressure of the AT hydraulic unit 53 is released (step 11
8) Then, a predetermined time is set in the timer for closing the electromagnetic opening / closing valve 6, and after waiting for a predetermined time in order to completely release the hydraulic pressure, the engine 1 is started (step 11).
2).

In this embodiment, as described above, the engine 1 is processed by the processing of step 92 (or fuel cut during deceleration).
Even if is stopped and oil pressure is no longer supplied by the oil pump 51, the check valve 63 and the accumulator 65 maintain the oil pressure of the AT hydraulic unit 53. Therefore, in step 110, it is possible to shift the automatic transmission 9 to the starting shift after the engine 1 is stopped and before the engine 1 is restarted in step 112. As described above, since the clutch of the automatic transmission 9 is engaged in the starting shift state before the engine is started, step 1
When the engine 1 is restarted at 12, the automatic transmission 9
It is possible to prevent a shock when the clutch is connected.

The process for fixing the starting shift in step 110 is not limited to the position shown in FIG. 5, but may be performed at any position after the engine 1 is stopped and before the engine is restarted. Good. For example, it may be immediately after step 92. FIG. 6 shows a timing chart when the vehicle using the automatic start-stop system of the present embodiment temporarily stops at an intersection and then travels again.

When the vehicle approaches an intersection, the vehicle speed starts to decrease at time t0, the accelerator opening becomes 0 at time t1, the idle switch 15b is turned on, and the vehicle speed becomes 0 at time t2, and the vehicle stops. After that (time t3), when the engine speed Ne decreases and falls below the idle speed, the engine 1 stops and the oil pressure by the oil pump 51 also decreases and becomes 0 after the engine rotation has stopped as indicated by the broken line. The hydraulic pressure of the hydraulic unit 53 is only slightly decreased by the action of the check valve 63 and the accumulator 65, as shown by the solid line, and the hydraulic pressure of the clutch of the automatic transmission 9 is maintained to be sufficient to continue the engaged state. . While stopped at the intersection, the hydraulic pressure of the AT hydraulic unit 53 is maintained in this state.

After that, the driver tried to start,
When the accelerator is depressed at time t4, step 102 in FIG.
Then, since the engine 1 is stopped, an affirmative determination is made. In step 104 as well, since the idle switch 15b is turned off by depressing the accelerator, an affirmative determination is made. Further, since the shift range is still in the D range, which is the state at the time of stop, a positive determination is also made in step 106. Therefore, next, steps 108, 110 and 112 are executed,
At time t6, the engine 1 starts and the vehicle starts running. Prior to this engine start, at time t5, the clutch of the AT hydraulic unit 53 is coupled to the starting shift state using the hydraulic pressure maintained in the AT hydraulic unit 53 by the processing of step 110, so that the engine 1 Even if the oil pump 51 starts to supply hydraulic pressure after starting, the clutch engagement shock does not occur, and the driver can start without causing discomfort to the driver.

If the check valve 63 and the accumulator 65 do not exist as in the conventional case, the hydraulic pressure of the AT hydraulic unit 53 decreases from time t3 similarly to the hydraulic pressure of the oil pump 51 shown by the broken line, and after the engine 1 is stopped. It becomes 0. At this time, the actual shift is in the disengaged state of the clutch of the AT hydraulic unit 53 as shown by the broken line. Therefore, after the engine starts at time t6, when the hydraulic pressure rises to a sufficient hydraulic pressure for clutch engagement at time t7, the rising line of the engine speed Ne shown by the broken line is bent, The clutch 1 is engaged with the engine 1 whose rotation speed Ne has been rapidly increased until then, and a sudden load is applied to the engine 1 to give a shock to the vehicle. This is not the case in this embodiment.

After the engine 1 is stopped by turning off the ignition switch 20 in the vehicle using the automatic start-stop system of the present embodiment, the ignition switch 2 is turned on.
FIG. 7 shows a timing chart when the engine 1 is started when 0 is turned on. When the ignition switch 20 is turned on and further rotated to the start position at time t11, the engine 1 is stopped, the idle switch 15b is turned on, and the range is the P range. Therefore, steps 102, 104, After the processing of 120 and 116, residual pressure relief processing is performed in step 118. That is, an open signal is output from the control circuit 37 to the electromagnetic opening / closing valve 67, the electromagnetic opening / closing valve 67 is opened, and the hydraulic pressure becomes zero. Next, in order to completely set the hydraulic pressure to 0, after a while, the starter 5 is driven and the engine 1 is started at time t12 (step 11).
2). In this way, when the engine speed Ne increases to the idle speed, the original oil pump 51 of the automatic transmission 9 is actuated by the driving force of the engine 1 to slightly increase the hydraulic pressure. At time t13, step 118 is reached. Since the electromagnetic on-off valve 67 is closed at the time when the timer is set, the hydraulic pressure rises more rapidly and becomes a sufficient hydraulic pressure at time t14 and becomes constant. If the engine 1 is started in this way, thereafter, the driver may depress the accelerator by preparing for starting such as releasing the parking brake 17 or setting the shift range to any one of D, L and S ranges. The vehicle starts.

Next, a second embodiment will be described. Example 2
Is different from the accumulator 65 of the first embodiment only in that an electric hydraulic pump 71 is used, and the other configurations are the same as those of the first embodiment. The schematic configuration is shown in FIG. The motor 71 a of the electric hydraulic pump 71 is the battery 7 of the engine 1.
Supplied from 3. Therefore, since the battery 73 is constantly charged with electric power supplied from the alternator when the engine 1 is driven, the electric hydraulic pump 71 can be driven even when the engine 1 is stopped. However, when the engine 1 is stopped by turning off the ignition switch 20, it is not necessary to maintain the hydraulic pressure. Therefore, a switch interlocking with the ignition switch 20 is provided between the battery 73 and the motor 71a. May be turned off at the same time that is turned off. Considering that if this switch is provided, the hydraulic pressure leaks while the vehicle is stopped with the ignition switch 20 off, even if the electromagnetic opening / closing valve 67 is not provided,
Next, turn on the ignition switch 20 to turn on the engine 1.
Since the clutch is naturally disengaged when the engine is started, it is possible to produce the same operation and effect as in step 118. Of course, an electromagnetic opening / closing valve 67 may be provided as shown in FIG. 8 to surely release the residual pressure.

Further, instead of the above-mentioned engine starting process,
If the following treatment is adopted, it is possible to obtain a better action and effect. 9 and 10 are flowcharts showing another embodiment of the engine starting process. Step 10
The processing of 2 to 122 is similar to the processing of FIG. When the start-up of the engine 1 in step 112 is completed, the engine stall state disappears, and a negative determination is made in step 102 and the process proceeds to step 131.
Various methods are conceivable as a method for determining whether or not the engine 1 is in an engine stall state. For example, is the engine speed Ne lower than a predetermined speed (for example, 200 rpm)? You may judge based on whether or not.

At step 131, it is confirmed that the ignition switch 20 is turned on. Normally, an affirmative determination is made here, and in subsequent steps 133 and 135, the engine speed Ne, the driving wheel speed Nw, and the gear ratio K are read.
Here, the drive wheel speed Nw is calculated by a known calculation based on the vehicle speed signal of the vehicle speed sensor 23. Also, the gear ratio K
Is calculated according to the gear position of the automatic transmission 9 detected based on the drive states of the solenoid valves 10a and 10b.

In the following step 137, Ne / (Nw · K) is calculated based on the read value, and it is determined whether or not the value is below a preset positive predetermined value C2. If it is not below the threshold, the routine proceeds to step 139, where a fuel cut signal is output to some of the cylinders of the engine 1, and the processing is temporarily terminated. Further, Ne / (Nw · K) <C2, and if an affirmative decision is made in step 137, step 1
Move to 41. In step 141, the output of the fuel cut signal is stopped, normal fuel injection is executed, and the subsequent step 1
Move to 43.

At step 143, Ne / (Nw · K)
It is determined whether or not <C1. Where C1 is 0 <
It is a predetermined value preset so as to satisfy C1 <C2. When a negative determination is made in step 143, the ignition signal generation timing is retarded (step 145), and the process ends. If the determination is affirmative, the ignition signal generation timing is returned to the normal timing (step 14
7) Once the processing is completed.

When the ignition switch 20 is off (step 131: NO), the process is terminated without doing anything. Then, the ignition switch 20 is turned on again, and the process stands by while repeating the processing of steps 102 and 131 until the engine 1 is started.

Here, the above-mentioned value Ne / (Nw · K) is the ratio of the rotational speeds of the input shaft and the output shaft of the torque converter 61, and this value is the load applied to the power transmission system such as the automatic transmission 9. Is known to have a good correspondence. Therefore, in the above process, the output of the engine 1 is decreased by the ignition retard when Ne / (Nw · K) becomes equal to or greater than the predetermined value C1. Further, when Ne / (Nw · K) further increases and becomes equal to or greater than the predetermined value C2, the fuel cut is executed in some cylinders to further reduce the output of the engine 1.

Therefore, even when the accelerator is rapidly depressed (step 104: YES) and the engine 1 is restarted (step 112), a large load is prevented from being applied to the power transmission system such as the automatic transmission 9. At the same time, idling of the drive wheels can be prevented. Therefore, the durability of the power transmission system can be favorably improved and the vehicle noise can be favorably reduced.

In the above process, the predetermined value C1 is set so that Ne / (Nw · K) <C1 is satisfied during normal traveling immediately after the start. Therefore, during normal traveling, normal engine output control is executed in steps 141 and 147. In the above processing, C1 ≤
When Ne / (Nw · K) <C2, only the ignition retard is executed to reduce the engine output in a relatively small amount, and C2 ≦ Ne
In the case of / (Nw · K), the engine output is relatively greatly reduced by the fuel cut. Therefore, the engine output can be gradually reduced according to the load applied to the power transmission system. Therefore, the engine output according to the above load can be constantly maintained, and the durability of the power transmission system, low noise, the riding comfort of the vehicle, and the like can be further improved.

In the above embodiment, the engine output is controlled based on the value of Ne / (Nw · K).
It may be controlled based on the difference between w and K.
You may control based on the map etc. which made w * K the vertical axis | shaft or the horizontal axis, respectively. In this case as well, the engine output is controlled according to the load of the power transmission system, and it is possible to obtain substantially the same actions and effects as in the above embodiment. Also, drive wheel speed N
The w may be directly detected by a sensor provided on the driving wheel. Further, the engine output may be controlled by providing the intake manifold 11 with a sub throttle valve. Also in these cases, it is possible to obtain substantially the same actions and effects as those of the above embodiment.

Further, although not included in the gist of the present invention, in a normal vehicle not equipped with a hydraulic pressure maintaining means such as the check valve 63, the above steps 131 to 147 are performed at the time of restart without the ignition switch 20. You may make it perform a process. Even when such a configuration is adopted, it is possible to prevent a large load from being applied to the power transmission system such as the automatic transmission 9 and prevent the drive wheels from idling.

In each of the above-described embodiments, the check valve 63 and the accumulator 65, or the check valve 63 and the electric hydraulic pump 71 correspond to the hydraulic pressure maintaining means, and the above-mentioned sensor or switch for outputting a signal to the control circuit 37 is used. It corresponds to a sensor group that detects the states of the engine and each part of the vehicle. In particular, the vehicle speed sensor 23 and the ignition primary coil 7a correspond to the first detecting means and the second detecting means, respectively. Further, the control circuit 37 includes an engine stopping means, an engine restarting means,
It corresponds to the stop time processing means, the residual pressure discharging means, and the engine output control means. Among the processing, the processing of steps 82 to 92 corresponds to the processing as the engine stopping means, and the processing of steps 102 to 106 and 112. The process of step 110 corresponds to the process as the engine restart means, and the process of step 110 corresponds to the process as the stop time processing means.
The processing of No. 8 corresponds to the processing as the residual pressure discharging means, and the processing of steps 133 to 145 corresponds to the processing as the engine output control means.

[Brief description of drawings]

FIG. 1 is a system configuration diagram of an embodiment.

FIG. 2 is a detailed configuration diagram of the control circuit.

FIG. 3 is a schematic configuration diagram of an automatic transmission according to a first embodiment.

FIG. 4 is a flowchart of an engine automatic stop process executed by a control circuit.

FIG. 5 is a flowchart of an engine starting process of the same.

FIG. 6 is a timing chart showing an operating state of the embodiment at an intersection or the like.

FIG. 7 is a timing chart when the engine is started by an ignition switch.

FIG. 8 is a schematic configuration diagram of an automatic transmission according to a second embodiment.

FIG. 9 is a flowchart showing another example of the engine starting process.

FIG. 10 is a flowchart showing another example of the engine starting process.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 ... Engine 3 ... Injector 5 ... Starter 7a ... Ignition primary coil 9 ... Automatic transmission 10a, 10b ... Solenoid valve 15a ... Throttle position sensor 15b ... Idle switch 17 ... Parking brake 20 ... Ignition switch 21a ... Neutral range switch 21b ... Parking Range switch 21c ... Drive range switch 21d ... L range switch 21e ... S range switch 21f ... R range switch 23 ... vehicle speed sensor 25 ... parking brake switch 37 ... control circuit 39a ... door switch 39b ... light switch 39c ... air conditioner switch 39d ... hydraulic pressure Switch 39e ... Turn switch 39g ... Water temperature sensor 39
h ... Intake temperature sensor 39i ... Intake air amount sensor 51 ... Oil pump 53 ... AT hydraulic unit 53a ... Hydraulic path 63 ... Check valve 65 ... Accumulator 67 ... Electromagnetic on-off valve 71 ... Electric hydraulic pump 71a ... Motor 73 ... Battery

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Tokuro Omori 1-1, Showa-cho, Kariya city, Aichi Nihon Denso Co., Ltd.

Claims (7)

[Claims] 1. An automatic engine stop and start device for use in a vehicle equipped with a hydraulic automatic transmission capable of switching to various shifts by using hydraulic pressure from a hydraulic pressure source that generates hydraulic pressure by driving an engine as operating hydraulic pressure. An oil pressure maintaining means for maintaining the operating oil pressure even when the engine is stopped, a sensor group for detecting the states of the engine and each part of the vehicle, and an engine stop condition that does not depend on the operation of the ignition key based on the detection signals from the sensor group. Engine stopping means for stopping the engine when is satisfied, engine restarting means for restarting the engine when the engine starting condition is not satisfied by operating the ignition key based on the detection signal from the sensor group, After the engine is stopped by the engine stopping means, and the engine is restarted by the engine restarting means. Automatic engine stopping and starting apparatus being characterized in that and a stop processing unit to start shift the hydraulic automatic transmission before. 2. The engine automatic stop / start apparatus according to claim 1, wherein the oil pressure maintaining means is a means for maintaining an operating oil pressure of a clutch hydraulic unit of the hydraulic automatic transmission. 3. The hydraulic pressure maintaining means prevents the reverse flow of oil from the clutch hydraulic unit to the hydraulic pressure source side, and a hydraulic pressure to the clutch hydraulic unit regardless of the driving force of the engine. The automatic engine stop and start device according to claim 2, further comprising: a hydraulic pressure supply means for supplying. 4. The engine automatic-stop starting device according to claim 3, wherein the hydraulic pressure supply means is an accumulator. 5. The engine automatic stop / start device according to claim 3, wherein the hydraulic pressure supply means is an electric hydraulic pump that uses a battery as a power source. 6. An on-off valve capable of releasing the working hydraulic pressure when opened, and an engine start operation by operating an ignition key under a predetermined condition based on a detection signal from the sensor group, The automatic engine stop starter according to any one of claims 1 to 5, further comprising: residual pressure discharge means for temporarily opening the on-off valve. 7. The sensor group comprises first detecting means for detecting the rotational speed of the drive wheel and second detecting means for detecting the rotational speed of the engine, and further, the detected drive wheel 7. The engine automatic stop and start device according to claim 1, further comprising engine output control means for controlling the output of the engine based on the correspondence between the rotation speed and the rotation speed of the engine.