JP2996434B2 - Automatic transmission with hill start assistance device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to start control of a vehicle having an automatic transmission with a hill start assist device.

[0002]

2. Description of the Related Art In order to prevent a vehicle from rolling down on a hill start, there is an automatic transmission equipped with a hill start assistance device that maintains brake fluid pressure under a certain condition even when a foot is released from a brake pedal. This device comprises a brake hold valve 64 'arranged between a brake valve 68' and air boosters 70 'and 72' as shown in FIG. 7, a control unit 20 ', and a control unit 20'.
And a magnetic valve 38 'for receiving an electric signal and sending an air signal to the brake hold valve 64'.

The brake hold valve 64
′ Operates when the vehicle speed becomes zero or a value close to zero at the time of braking, the clutch is automatically disengaged (characteristic of an automatic transmission having a mechanical clutch), the accelerator pedal opening is zero, and the brake pedal is released. Stepping for a fixed time (for example, 1
Seconds), when power is supplied to the magnetic valve 38 ', the magnetic valve 38' is opened and, as shown in FIG.
The signal pressure enters through the vent hole 61 of the brake hold valve 64 ′, and the plunger 62 resists the return spring 63.
Is pushed down, and the tip of the plunger 62 is
7 does not come into contact with the brake valve 68 'side vent 6
9 and the air booster 70 'side vent 73 are shut off, so that the brake fluid pressure is maintained.

The operation of the brake hold valve 64 'is released immediately when the accelerator pedal is depressed and the clutch is automatically engaged, and when the foot is released from the brake pedal (for a certain period of time). After 2 seconds), the magnetic valve 38 'is turned off, and as shown in FIG. 5, the signal pressure does not flow in from the vent 61 of the brake hold valve 64', so that the plunger 62 rises due to the reaction force of the return spring 63 and is checked. The valve 67 is pushed up, and the vent 69 on the brake valve 68 'side communicates with the vent 73 on the air booster side to release the brake hold.

[0005] However, the above-mentioned prior art has a safety problem as described below.

This will be described with reference to a timing chart shown in FIG. 6 showing the relationship between the behavior of the accelerator sensor, the brake hold magnetic valve, the clutch and the brake switch and the vehicle speed when the vehicle starts on a slope, and FIG.

More specifically, a brake switch D46 'is provided in the brake air circuits L2' and L2 'as conditions for starting braking and conditions for detecting clutch disengagement operation control for preventing engine stall before stopping the vehicle in the automatic transmission. During hold operation (A accelerator sensor is not depressed (a
1), the B brake hold magnetic valve 38 'is ON (b1), the C clutch is disconnected (c1), the D brake switch 46' is OFF (d1), and the E vehicle speed is 0 (e1). ) Indicates the atmospheric pressure in the pipe L2 ′, and the pipe L3
′ Is pressurized air is confined. afterwards,
When the driver tries to start on a slope, the brake valve 68
'Release the foot from the (brake pedal) and depress the accelerator (A accelerator sensor is depressed (a2 to a3), B
Brake hold magnetic valve 38 'is OFF
(B2), the C clutch is engaged (c21 to c22), and the E vehicle speed is increasing from zero (e2). ), The brake hold is released, and the air accumulated in L3 'is released to the atmosphere via the pipe L2' and the brake valve 68 '. At this time, the pipe of L2 'and the brake valve 68'
Brake switch 46 'between the air discharge ports
Turns on (d2) in response to the air accumulated in L3 ', the C-clutch is automatically disengaged, and the E-vehicle speed stalls despite the depression of the A accelerator sensor (a3). Had the problem of retreating.

That is, even though the driver has not depressed the brake pedal 88, the controller 20 receives a signal that the brake has been depressed.

[0009]

SUMMARY OF THE INVENTION Accordingly, in order to solve the above-mentioned problem, the present invention aims to solve the above problem by immediately releasing the brake hold during starting on a slope and releasing the air remaining in the air circuit. The brake switch turns on,
An object is to prevent a situation in which the clutch is disengaged.

[0010]

According to the present invention, there is provided an automatic transmission for automatically shifting gears and engaging and disengaging clutches based on a pattern set in advance according to the driving condition of the vehicle, and detects the vehicle speed. Vehicle speed detecting means, an accelerator sensor for detecting an accelerator opening, a brake state detecting means for detecting on / off of a brake by a brake operating air pressure, a clutch stroke detecting means for detecting a clutch stroke, and a brake for a wheel cylinder In an automatic transmission with a slope start assist device including a brake fluid pressure adjusting means for adjusting a fluid pressure and a control means, the control means determines whether the vehicle speed is zero or zero based on signals from various detection means including the accelerator sensor. When the clutch is disengaged due to the brake being on in a state close to zero, the brake fluid pressure adjustment means A control signal for holding the rake hydraulic pressure is output, and the hold control signal is released in accordance with the connection of the clutch. The control means is further provided after releasing the hold of the brake hydraulic pressure and before a predetermined time elapses. In the case where a signal indicating that the brake is on is generated from the brake state detecting means and the accelerator opening is not zero, it is determined that the brake is not on and the control that does not generate the clutch disconnection control signal is performed. Includes circuitry.

[0011]

According to the present invention, since the brake switch (brake pedal detecting means) is constituted as a pressure sensor, the air is released immediately after the brake hold is released (immediately after the brake fluid pressure is removed) when the vehicle starts on a slope. When the air remaining in the circuit is discharged, the brake switch is operated by the dynamic pressure of the air, and a signal indicating that the brake switch is ON is generated.

However, according to the present invention, since the "control circuit which determines that the brake is not on and does not generate a control signal for disengaging the clutch" is provided, after the brake fluid pressure is removed, If the signal indicating that the brake switch is ON is generated before the predetermined time has elapsed, the signal is ignored.

Accordingly, the clutch is disengaged immediately after the vehicle starts on the slope, and the propulsion of the vehicle is reduced to zero, thereby preventing the vehicle from moving backward.

[0014]

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

FIG. 1 shows the brake fluid pressure adjusting means. The air reservoir 62 is connected to a brake valve 68 by an air circuit L1, and hold valves 64 and 66 are connected to the brake valve 68 in parallel by an air circuit L2. These hold valves 64 and 66 are respectively connected to the left and right air boosters 7 by air circuits L3 and L3.
0 and 72, and also connected to the air circuit L1 by the air circuit L4. A magnetic valve 38 is interposed in the air circuit L4.
Reference numeral 8 denotes a three-port two-position type, in which an operating part is opened when turned on, and the operating part is connected to a controller 20 as control means. The controller 20 is connected with a brake switch 46 as a brake pedal detecting means, a vehicle speed sensor 1 and a clutch stroke sensor 3 as means for detecting a vehicle speed.

The hold valves 64 and 66 are connected to the air circuit L2 and the air circuit L when the magnetic valve 38 is on.
3, the brake fluid pressure is interrupted, or the brake fluid pressure is maintained (see FIG. 4), and when the magnetic valve is off, the air circuit L2 is connected to the air circuit L3 to connect the brake valve 68. (I.e., normal braking is possible).

Next, a control flow will be described with reference to FIG. 1 based on FIG.

When starting in the brake hold state, the controller 20 first determines in step S1 whether the brake switch 46 is ON. If NO, the process proceeds to step S5, in which it is determined that the brake switch 46 is not ON, that is, the control signal is not output to the magnetic valve 38 that controls the clutch.

If it is determined in step S1 that the brake switch 46 is ON (YES), the flow advances to step S2 to determine whether or not the brake hold has been released.
It is determined whether or not the brake hold valves 64 and 66 are in the released state. If YES, the process proceeds to step S3. Then, it is determined whether it is within a predetermined time (t seconds) after releasing the brake hold,
If YES, the process proceeds to step S4, and it is determined whether or not the accelerator pedal is depressed. If YES, it is determined in step S5 that the brake switch 46 is not on (although it is on). Step S2 is NO (brake hold, that is, brake hold valve 6
4 and 65 are not released), step S3 is N
If O (one second or more has elapsed after the release of the brake hold) and step S4 is NO (when the accelerator is depressed), the process proceeds to step S6, where the brake switch 46 is determined to be on as indicated by the signal, The predetermined control is continued.

[0020]

As described above, according to the present invention, even if the brake switch is operated (ON) during the release of the brake hold, the controller is made to judge that the brake switch is ignored. Since it is possible to prevent a phenomenon in which the clutch is suddenly disengaged, the driving force is not generated, and the vehicle retreats, the safety is enhanced, and the driver can feel secure.

[Brief description of the drawings]

FIG. 1 is an overall configuration diagram showing a brake fluid pressure adjusting unit according to an embodiment of the present invention.

FIG. 2 is a control block diagram of the present invention.

FIG. 3 is a control flowchart of the present invention.

FIG. 4 is a sectional view of a brake hold valve (when a brake hold is activated).

FIG. 5 is a sectional view of the brake hold valve (when the brake hold is released).

FIG. 6 is a timing chart showing the relationship between the behavior of an accelerator sensor, a brake hold magnetic valve, a clutch, and a brake switch and a vehicle speed according to a conventional technique.

FIG. 7 is an overall configuration diagram of a conventional brake system including brake fluid pressure adjusting means.

[Explanation of symbols]

 20: controller 38: magnetic valve 46: brake switch 50: clutch stroke sensor 56: vehicle speed sensor 64, 66: hold valve 68: brake valve 70, 72 ...・ Air booster

Claims (1)

(57) [Claims] An automatic transmission for automatically shifting gears and engaging and disengaging a clutch based on a pattern set in advance according to a driving condition of a vehicle, a vehicle speed detecting means for detecting a vehicle speed, and an accelerator opening An accelerator sensor for detecting the degree of braking, a brake state detecting means (46) for detecting on / off of a brake by a brake operating air pressure, a clutch stroke detecting means (3) for detecting a stroke of a clutch, and a brake fluid for a wheel cylinder. Brake fluid pressure adjusting means (64, 66) for adjusting the pressure;
0), the control means (20) sets the vehicle speed to zero or zero based on signals from various detection means (1, 46, 3) including the accelerator sensor. When the clutch is disengaged due to the on state of the brake in a close state, a control signal for holding the brake fluid pressure is output to the brake fluid pressure adjusting means (64, 66), and the hold control signal depends on the connection of the clutch. The control means (20) is further configured to release the brake from the brake state detection means (46) after the brake fluid pressure is released and before a predetermined time (t) elapses. When a signal to the effect is generated and the accelerator opening is not zero, it includes a control circuit that determines that the brake is not on and does not generate a control signal for disengaging the clutch. Automatic transmission with hill-start assist to.