JPH07144625A - Stop/start controller for vehicle - Google Patents

Abstract

PURPOSE:To reduce the loss accompanied with the stop in a D-range for an A/T vehicle, automatically applying brake during stop, and realize the excellent start afterwards. CONSTITUTION:The line pressure of the hydraulic system 15 of an automatic transmission 14 is lowered by a controller 8 by detecting the stop of a vehicle by a stop state detecting means 1, and wheels 7 are brake-applied automatically by a brake 6 through a brake force adjusting means 16, while the line pressure in the hydraulic system 15 is returned to an original value by the controller 8 by detecting the start of the vehicle by a start detecting means 10, and the brake application for the wheels 7 by the brake 6 is automatically released through the brake force adjusting means 16.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a vehicle stop / start control device, and is particularly useful when applied to a vehicle equipped with an automatic transmission (hereinafter referred to as an A / T vehicle).

[0002]

2. Description of the Related Art In A / T vehicles, which are rapidly becoming popular today, especially when the vehicle is stopped while waiting for a signal, etc., while driving in the city, it is possible to drive the D (drive) lever without setting the transmission operation lever to the N (neutral) range. ) It may be stopped in the range. At this time, the engine is idling.

[0003]

As described above, in an A / T vehicle, if the vehicle is stopped in the D range, the loss in the torque converter of the automatic transmission and the oil pump of the hydraulic system for supplying the pressure oil to the torque converter will be described. Since the loss becomes larger than that when the vehicle is stopped in the N range, there is a problem that fuel consumption becomes worse and vibration due to engine idling is large at the same time.

On the other hand, when the A / T car is stopped in the D range,
A creep phenomenon in which the vehicle body gradually starts to move even when the engine speed is idling may occur, but in order to avoid this, the operator must continue to step on the brake pedal, which is a cause of operator fatigue. Becomes

On the contrary, when the vehicle is stopped with the brake pedal released, there is a problem that the vehicle is weak in the case of a rear-end collision.
That is, as compared with the case where the brake pedal is depressed, the vehicle body tends to jump forward at the time of a rear-end collision, which may cause an unexpected accident such as a collision of balls.

In view of the above-mentioned prior art, the present invention reduces the loss associated with the stoppage of the A / T vehicle in the D range as much as possible, and automatically brakes while the vehicle is stopped, and thereafter It is an object of the present invention to provide a stop / start control device for a vehicle that can realize a good start of the vehicle.

[0007]

In order to achieve the above object, the structure of the present invention has a driving state detecting means for detecting a driving state of a vehicle, and a shift position based on the vehicle driving state detected by the driving state detecting means. A controlled automatic transmission, braking means for braking the wheels of the vehicle with a braking force according to the operation of the brake pedal, and the braking force of the braking means can be changed independently of the operation of the brake pedal. Braking force adjusting means, vehicle stop state detecting means for detecting that the vehicle is in the vehicle stop state based on the vehicle operating state detected by the operating state detecting means, and vehicle operating state detected by the operating state detecting means When the vehicle is in the stopped state by the start detection means for detecting the start of the vehicle based on the above, and the vehicle stop state detection means, the hydraulic pressure of the automatic transmission is lowered. In addition to controlling the braking force adjusting means to maintain the braking force for the wheels at a predetermined value, when the start detecting means detects the start of the vehicle, the hydraulic pressure is returned to the value before the decrease. And a control means for releasing the holding of the braking force by the braking force adjusting means.

[0008]

According to the present invention having the above-mentioned structure, when the vehicle stop state detecting means detects the stop, the control means reduces the hydraulic pressure of the automatic transmission and the braking force to the wheels is brought to a predetermined value via the braking force adjusting means. Hold.

After that, when the start detecting means detects the start, the control means restores the hydraulic pressure of the automatic transmission and releases the braking of the wheels via the braking force adjusting means.

[0010]

Embodiments of the present invention will now be described in detail with reference to the drawings.

FIG. 1 is a block diagram showing an embodiment of the present invention. As shown in the figure, the vehicle stop state detecting means 1 includes a vehicle speed signal S ₁ indicating a vehicle speed which is an output signal of each of the vehicle speed detecting means 2, the accelerator opening detecting means 3, the braking force detecting means 4 and the gradient sensor 5, an accelerator pedal. Accelerator opening signal S indicating opening
_{2. By} inputting and processing the braking force signal S ₃ representing the braking force acting on the wheels 7 via the brake 6 serving as the braking means and the gradient signal S ₄ representing the gradient of the road, the following three conditions are obtained. When the conditions are satisfied at the same time, it is determined that the vehicle is in the stopped state and the stop detection signal S ₅ is supplied to the control means 8.

3 for determining that the vehicle is stopped
The condition is that the detected vehicle speed is equal to or lower than a predetermined value,
The accelerator pedal is not stepped on, and the braking force is larger than a predetermined braking force for a predetermined time.

Here, the accelerator opening detecting means 3 also functions as an accelerator operation detecting means for detecting whether or not the accelerator petal is stepped on. That is, when the opening degree detected by the accelerator opening degree detecting means 3 is zero, it corresponds to a state in which the accelerator pedal is not stepped on. Braking force detection means 4
Can be configured by, for example, a hydraulic pressure sensor that detects the hydraulic pressure acting on the brake 6, that is, the brake hydraulic pressure.
Further, the gradient sensor 5 can be configured by a G sensor that detects the gravitational acceleration G caused by the inclination of the vehicle body, and the vehicle stop state detection means 1 is necessary to stop at the gradient detected based on the gradient signal S _4. A predetermined braking force is calculated and compared with the braking force signal S ₃ . That is, the driver's intention to stop the vehicle is detected by detecting that the brake pedal 9 is stepped on so that a braking force larger than the predetermined braking force acts on the wheels 7 via the brake 6.

The transmission detecting means 10 includes the accelerator opening signal S ₂ , the braking force signal S ₃ , the gradient signal S ₄ and the vehicle stop detection signal S _5, and the brake pedal 9 which is an output signal of the brake operation detecting means 11. By inputting and processing the brake actuation signals S ₆ indicating that the pedal is stepped,
When any of the following conditions is satisfied, it is determined that the vehicle has started to start, and the start detection signal S ₇ is supplied to the control means 7.

The condition for determining that the vehicle has started to start is that the brake pedal 9 is once released and then stepped on again after the vehicle stop state is detected by the vehicle stop state detecting means 1. This is the case when it is detected and the braking force is larger than a predetermined braking force, or when it is detected that the accelerator pedal is stepped on.

Here, the stop state of the vehicle indicates the stop detection signal S.
₅ , the brake pedal 9 is operated by the brake operation signal S ₆ ,
If the braking force is greater than the predetermined braking force, it means that the braking force signal S ₃
The fact that the gradient signal S ₄ and the accelerator pedal are stepped on can be detected by processing the accelerator opening signal S ₂ . At this time, the brake operation detecting means 11 may be configured by a brake switch whose state changes by stepping on the brake pedal, for example. Further, the processing of the braking force signal S ₃ and the gradient signal S ₄ is similar to the processing of the vehicle stop state detecting means 1, that is, the predetermined braking force required to stop at the detected gradient and actually acts on the wheels 7. The braking force that is being applied.

The control means 8 includes a gradient signal S ₃ , a vehicle stop detection signal S ₅ , a transmission detection signal S ₇ and an engine output detection means 1.
The engine output signal S ₈ representing the output of the engine 13, which is the output signal of No. 2, is processed to perform the following control.

That is, when the vehicle stop state is detected by the vehicle stop state detecting means 1, the line pressure of the hydraulic system 15 of the automatic transmission 14 is reduced and the brake 6 is controlled via the braking force adjusting means 16. , The braking force on the wheels 7 is maintained at a predetermined pressure.

As shown in FIG. 2, the hydraulic system 15 at this time basically has a structure in which one solenoid valve 17 is added to the existing one, but the pressure oil pumped by the oil pump 18 is used. The automatic transmission 14 is configured to be supplied to each predetermined part including a torque converter, and when the stop state of the vehicle is detected, the solenoid valve 17 is opened by the hydraulic control signal S ₉ to open the oil pump. The pressure oil pumped up at 18 is drained to the oil pan 19 and the line pressure (A in the figure,
The pressure of the portion B) is reduced.

As a result, when the solenoid valve 17 is opened and the line pressure is decreasing, the pressure loss due to the oil pump 18 and the torque converter is reduced even in the D range.
Reduced to the same extent as in the N range, and engine 1
The noise caused by idling 3 is also reduced.

The manual valve 20 shown in FIG.
It operates by operating the shift lever of the driver to set the shift range of the automatic transmission 14, and the regulator valve 21 adjusts the hydraulic pressure of the pressure oil supplied to the torque converter (not shown) of the automatic transmission. It is for.

The braking force adjusting means 16 shown in FIG.
The braking force of the brake 6 is controlled based on the braking force adjustment signal S ₁₀ of the control means 8 independently of the operation of the brake pedal 9.

On the other hand, when the start detecting means 10 detects the start of the vehicle, the line pressure of the hydraulic system 15 of the automatic transmission 14 is restored and the brake 6 is controlled via the braking force adjusting means 16. , Release the braking on the wheels 7. That is, the solenoid valve of the hydraulic system 15 is closed and the pressure oil of a predetermined pressure pumped up by an oil pump is supplied to a predetermined hydraulic device such as a torque converter.

At this time, in this embodiment, the engine output signal S ₈ detected by the engine output detecting means 12 is processed,
The braking at this time is released under the condition that the engine torque represented by the engine output signal S ₈ exceeds a predetermined torque T ₁ . In other words, if the braking force is released when the vehicle starts on a slope or the like, the vehicle body may move backward. Therefore, by releasing the braking at the start of the vehicle on condition that the above conditions are satisfied, it is possible to prevent the vehicle from moving backward. It is configured so that a smooth start of the vehicle can be realized.

The backward movement preventing function will be described in more detail. The engine output detecting means 12 obtains engine torque information based on the throttle valve opening information and the engine speed information, and the predetermined engine torque T ₁ is specified according to the inclination angle of the vehicle body detected by the gradient sensor 5. The calculated torque is calculated based on the gradient signal S ₄ . That is, when the engine torque detected by the engine output detecting means 1 is larger than a predetermined engine torque T ₁ determined by the inclination angle of the vehicle body (the inclination angle of the road), the vehicle does not move backward. The reason for this is as follows.

In FIG. 3 (a), 22 is a torque converter, 22a is its turbine, 22b is an impeller, and 22b.
c is the stator, 22d is the input shaft of the torque converter 22 which is the output shaft of the engine, 22e is the output shaft of the torque converter 22 which is the input shaft of the transmission, T ₁ is the input torque (output torque of the engine), T ₂ is the output Torque (transmission input torque), n ₁ is the rotational speed of the input shaft 22d, and n ₂ is the rotational speed of the output shaft 22e.

As shown in FIG. 3, the torque converter 22
The rotation speed of the turbine 22a is the same as the rotation speed of the output shaft 22c, which is the input shaft of the transmission, and the rotation speed is almost the same as the engine rotation speed in the N range. Are coupled to rotate at a rotation speed of wheel rotation speed × reduction ratio. Therefore, the rotation speed of the turbine 22a when the vehicle is stopped, that is, n ₂ = 0.

Therefore, based on the characteristics of the torque converter,
n₂Torque ratio t when T = 0 (= T ₂/ T₁) Is obtained
So the engine torque T₁If you know
Output torque T₀= T₁× t × ρ (however, ρ is deceleration
Ratio) is obtained. As a result, the wheel driving force D = (T₀× De
Ratio) / (radius of wheel). Therefore, the road
If you know the distribution, you can calculate the driving force D for not going backward.
Therefore, based on this driving force D
Engine torque T₁Is required.

Further, when the start detecting means 10 detects the start of the vehicle, the accelerator pedal is higher than that after the line pressure of the hydraulic system 15 returns to the value before the decrease (the value before the stop condition is detected). The engine 13 is controlled by the engine output control signal S ₁₁ so as to increase the engine output at a low increase rate with respect to the increase in the manipulated variable. As a result, it is possible to prevent a shock from being generated in a transient state until the hydraulic pressure returns to a predetermined pressure, and to perform a good start.

In this embodiment, the driving state detecting means for detecting the driving state of the vehicle are the vehicle speed detecting means 2, the accelerator opening detecting means 3, the braking force detecting means 4, the gradient sensor 5, the brake operation detecting means 11 and the engine output. The detection means 12.

Although not shown in order to avoid complication of the drawing, the control means 8 and the automatic transmission 14 process the output signals of the respective driving state detecting means to appropriately output the engine 13 based on the driving state of the vehicle. Control and select an appropriate shift position. That is, the engine output control and the gear shift position control similar to the conventional one can be performed.

FIG. 4 is a flow chart showing the control when the vehicle is stopped in this embodiment. As shown in the figure, in the vehicle stop state detecting means 1, when the vehicle speed is 0 and the accelerator opening is zero (see step _St1 ), the brake pressure proportional to the depression amount of the brake pedal 9 is detected. When it is detected that the pressure is equal to or higher than a predetermined pressure specific to the gradient (see step S _t2 ) and this state continues for 2 seconds or more (see step S _t3 ), the vehicle stop detection signal S is sent to the control means 8. ₅ is sent out, the solenoid valve of the hydraulic system 15 is opened by the hydraulic pressure control signal S ₉ and the braking force adjustment signal S ₁₀ which are the output signals of the control means 8 (see step _St4 ), and the braking force adjustment means 16 is used. The brakes 6 brake the wheels 7 (see step _St5 ). That is, the driving that satisfies the above-mentioned three conditions performs a predetermined process in the stop mode as a reflection of the driver's intention to stop. As a result, in the hydraulic system 15, the pressure oil pumped up by the oil pump is drained to the oil pan and the line pressure is reduced. Therefore, even when the automatic transmission 14 is in the D range, the load on the oil pump and the load on the torque converter are not increased. It will be reduced. Further, even if the brake pedal 9 is released, the wheels 7 continue to be braked with a predetermined pressure. That is, the brake pressure controlled by the braking force adjusting means 16 has the characteristic shown by the solid line in the characteristic diagram of step _St5 . The dotted line in the characteristic diagram indicates the brake pressure obtained by depressing the brake pedal 9.

When the vehicle stop state detection mode described above is entered, the operation lamp indicating this mode is turned on (see step _St6 ).

FIG. 5 shows cancellation of the stop mode in this embodiment.
At the time, that is, the flow chart showing the control at the start of starting
is there. As shown in FIG.
The brake pedal 9 was once released and then stepped on again
Is detected, and the braking pressure at that time is controlled by the wheel 7.
In order to secure the dynamic state, the minimum angle peculiar to the body inclination angle θ
It is detected that the predetermined brake pressure P (θ) is exceeded.
(Step S_t7(See) or accelerator petal
When is depressed (Step S_t8Driver)
Predetermined processing as the start mode reflects the intention to start the start.
Do the reason. That is, the brake pedal 9 is stepped on again.
If the brake pressure is> P (θ), the start check is performed.
Outgoing signal S₇Is supplied to the control means 8 and the output of the control means 8
Braking force adjustment signal S, which is a force signal_TenBraking force adjustment means
Control of the brake 6 by 16 is stopped (step S_t9
(See) and then the hydraulic control signal S₉By hydraulic system
Driving the hydraulic system 15 by closing the solenoid valve 15
The line pressure to the original value (step S_t10reference).
As a result, the brake pressure is_t9Solid line in the characteristic diagram
As shown by, the breakage is shown in the figure
The pressure depends on the amount of depression of the Kipedal 9. Also oil
The pressure system 15 also returns to a normal operating state. On the other hand, step S_t7
When the accelerator pedal is stepped on even if the condition of
To step S _t10Solenoid valve 17 of hydraulic system 15
The hydraulic system 15 is set to the drive mode by closing the
To restore the original pressure (step S_t11reference). Then control hand
Stage 8 engine power control signal S₁₁Than usual
Increase in engine output with respect to the amount of depression of the xel pedal
Reduce the ratio (step S)_t12reference). Sanawa
Then, step S_t12As shown in the characteristic diagram of
The solid line indicates the throttle opening when the dull is depressed.
As shown in, with a smaller rate of change than the normal time shown by the dotted line
Increase gradually.

After that, the engine torque is
Predetermined torque to prevent backward movement, which is specified by the inclination angle of the vehicle body.
Luk T₁If it is detected that (θ) is exceeded (step
S _t13Refer to) for the braking force adjustment signal S_TenAdjusting the braking force by
The braking force of the brake 6 is gradually reduced via the means 16.
(Step S_t14reference). By such control,
It is possible to prevent a backward movement caused by a reduction in braking force on a slope or the like.

After the processing of step S _t10 or step S _t14 is completed, the operation lamp is turned off (step S
See _t15 ).

The vehicle stop / start control apparatus according to the present invention is not limited to the above-mentioned embodiment. The vehicle stop state is detected by some means to lower the hydraulic pressure of the hydraulic system 15 of the automatic transmission and the wheels 7 are braked by a predetermined braking force, while the start start state is detected by some means to restore the original hydraulic pressure. Each component and combination can freely do so long as it can control so as to release the braking force.

[0038]

As described above in detail with reference to the embodiments, according to the present invention, the hydraulic pressure of the A / T vehicle is reduced when the vehicle is stopped. Therefore, even when the automatic transmission is in the D range when the vehicle is stopped, the hydraulic pressure is reduced. Not only can the loss in the oil pump and the torque converter of the system be reduced to improve the fuel consumption, but also the noise due to the idle rotation of the engine at this time can be reduced.

Further, since a predetermined braking force is automatically applied to the wheels when the vehicle is stopped, the braking force is applied even if the driver releases the brake pedal, and the driver's fatigue can be reduced and at the same time from the rear. It is also possible to improve safety in the case of being hit by another vehicle.

Further, when the driver's intention to start is detected, the hydraulic system is restored to the original state and the braking force on the wheels is automatically released, so that a good start can be performed.

[Brief description of drawings]

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

FIG. 2 is an explanatory diagram showing a hydraulic system of the above embodiment.

FIG. 3 is an explanatory diagram showing a torque converter in the above embodiment.

FIG. 4 is a flowchart showing a processing procedure in a vehicle stop mode in the above embodiment.

FIG. 5 is a flowchart showing a processing procedure in a start mode in the above embodiment.

[Explanation of symbols]

 1 Vehicle Stop State Detection Means 2 Vehicle Speed Detection Means 3 Accelerator Opening Detecting Means 4 Braking Force Detecting Means 6 Brake 7 Wheels 8 Controlling Means 9 Brake Pedal 10 Start Detecting Means 11 Brake Operation Detecting Means 12 Engine Output Detecting Means 13 Engines 14 Automatic Shifting Machine 15 Hydraulic system of automatic transmission 16 Braking force adjusting means

─────────────────────────────────────────────────── ─── Continuation of the front page (51) Int.Cl. ⁶ Identification code Internal reference number FI technical display area F16H 59:44

Claims (6)

[Claims] 1. A driving state detecting means for detecting a driving state of a vehicle, an automatic transmission in which a shift position is controlled based on the vehicle driving state detected by the driving state detecting means, and a brake pedal depending on an operation. Braking means for braking the wheels of the vehicle by the braking force, a braking force adjusting means capable of changing the braking force of the braking means independently of the operation of the brake pedal, and the driving state detecting means. A vehicle stop state detecting means for detecting that the vehicle is in a vehicle stop state based on the vehicle operating state, and a start detecting means for detecting start of the vehicle based on the vehicle operating state detected by the operating state detecting means, When the vehicle stop state detecting means detects that the vehicle is in the vehicle stop state, the hydraulic pressure of the automatic transmission is reduced and the braking force adjusting means is controlled to control the wheels. The braking force for
When the start detection means detects the start of the vehicle, the control means resets the hydraulic pressure to the value before the decrease and releases the holding of the braking force by the braking force adjusting means. A vehicle stop / start control device. 2. The control means, when the start detection means detects the start of the vehicle, the control means has a lower rate of increase with respect to an increase in the operation amount of the accelerator pedal than after the hydraulic pressure returns to the value before the decrease. The vehicle stop / start control device according to claim 1, wherein the engine output is increased by means of. 3. The driving state detecting means detects a vehicle speed of the vehicle, an accelerator operation detecting means for detecting whether or not an accelerator pedal is stepped on, and a braking force of the braking means. Braking force detecting means, the vehicle stop state detecting means detects that the vehicle speed detected by the vehicle speed detecting means is a predetermined value or less and the accelerator pedal is not stepped on by the accelerator operation detecting means, and The vehicle stop / start control apparatus according to claim 1, wherein the vehicle stop / start control device determines that the vehicle is in a stopped state when a state in which the braking force detected by the braking force detection is larger than a predetermined braking force continues for a predetermined time. 4. The operating state detecting means has accelerator operation detecting means for detecting whether or not the accelerator petal is stepped on, and the start detecting means is that the accelerator petal is stepped on by the accelerator operation detecting means. The vehicle stop / start control device according to claim 1, wherein when it is detected, it is determined that the vehicle has started. 5. The driving state detecting means includes a braking force detecting means for detecting a braking force of the braking means, and a brake operation detecting means for detecting that the brake pedal is stepped on. The detecting means detects that the brake pedal is once released and then stepped on again after the vehicle stop state is detected by the vehicle stop state detecting means, and the braking force is detected. The vehicle stop / start control apparatus according to claim 1, wherein when the braking force detected by the means is larger than a predetermined braking force, it is determined that the vehicle has started. 6. The operating state detecting means has an engine output detecting means for detecting an output torque of the engine, and the control means is operable when the engine output torque detected by the engine output detecting means exceeds a predetermined torque. 2. The vehicle stop / start control device according to claim 1, wherein the holding of the braking force is started.