JP2002283979A - On-slope start auxiliary device of vehicle - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an on-slope start auxiliary device of a vehicle capable of controlling valve opening speed of a brake force holding valve in response to a stepping state of an accelerator pedal in releasing an HSA and avoiding backward movement of a vehicle in restarting on an uphill slope, sudden acceleration on a traffic snarl road, or the like. SOLUTION: This device comprises a fluid coupling 4 that is interposed between the engine 1 and the transmission 3 and generates the predetermined creep force in gear-in of the transmission 3, a brake force holding valve 61 that is disposed in a fluid pressure passage 60 of a brake, holds a brake force at this time in closing the valve, and releases the brake force in opening the valve, a gear-in sensor 46 for detecting the gear in of the transmission 3, an accelerator sensor 54 for detecting an opening amount and a stepping speed of an accelerator pedal 53, and a controlling part 56 for controlling the opening or closing of the brake force holding valve 61. When the gear-in sensor 46 detects the gear-in of the transmission 3 and the accelerator sensor 54 detects the stepping on the accelerator pedal 53 after the closing of the brake force holding valve 61, the controlling part 56 changes the valve opening/closing speed of the brake force holding valve 61 high or slow in response to the opening amount of the accelerator pedal 53 and stepping speed of the accelerator pedal 53.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a vehicle having a hill which retains the braking force even when the brake pedal is released and the brake pedal is released, and releases the braking force held at the time of starting. The present invention relates to a start assist device.

[0002]

2. Description of the Related Art Hill Start Ai
d: may be abbreviated as HSA in the following), which makes it easy to start on a slope without using a side brake (parking brake). When applying the HSA to a vehicle having a fluid coupling (including a torque converter) between an engine and a transmission (a vehicle with a so-called torque converter), the brake pedal is released when the brake pedal is depressed and stopped. The brake force is maintained even afterward, and then the brake force held when the accelerator pedal is depressed is released.

More specifically, a braking force for maintaining a braking force at that time by closing a passage in a fluid pressure passage between a master cylinder operated by a brake pedal and a wheel cylinder operating a wheel brake. As shown in FIG. 8, when it is detected that the brake pedal has been depressed, the vehicle has stopped, and that the gear is in neutral, the braking force holding valve is closed and the brake pedal is released. The brake force is maintained even after the release, and thereafter, as shown in FIG. 9, when the accelerator pedal is depressed in the gear-in state, the brake force holding valve is opened (HSA is released).

Here, the above-mentioned braking force holding valve is set to perform on / off control of full opening or full closing.

[0005]

However, after the HSA is actuated, when the HSA is released by depressing the accelerator in the gear-in state as shown in FIG. 9, when the braking force holding valve in the closed state is opened at a stroke, the HSA causes Since the held braking force is released at once, when the vehicle starts moving uphill, the holding brake force by the HSA is released before the creep force is sufficiently transmitted to the vehicle (wheels) and the vehicle stops. It may slip down.

When the vehicle is started on a congested road or a downhill, when the accelerator is depressed in a gear-in state and the HSA is released, the braking force holding valve in the closed state is opened at a stretch, and the HSA is held by the HSA. Since the braking force that has been applied is released at once, the possibility that the vehicle jumps out due to the creep force due to the gear-in and crashes into the preceding vehicle cannot be denied.

An object of the present invention, which has been made in view of the above circumstances, is to control the opening speed of a braking force holding valve in accordance with the state of depression of an accelerator pedal when releasing HSA, and to stop the vehicle uphill. It is an object of the present invention to provide a vehicle hill start assistance device that can prevent the vehicle from slipping down at the start and sudden start on a congested road.

[0008]

According to a first aspect of the present invention, there is provided a vehicle hill start assist device interposed between an engine and a transmission, which is provided with a predetermined creep force when the transmission is engaged. A braking force holding device that is interposed in the brake fluid pressure passage and closes the passage to hold the braking force at that time, and a control device that controls the operation and release of the braking force holding device. A vehicle having a slope start assist device, comprising accelerator opening amount detecting means for detecting the amount of depression of the accelerator pedal, after the operation of the braking force holding device, when the depression of the accelerator pedal is detected,
The release speed of the braking force holding device is made variable according to the magnitude of the accelerator opening.

The vehicle start assist system according to a second aspect of the present invention includes a fluid coupling interposed between the engine and the transmission for generating a predetermined creep force when the transmission is engaged, and a fluid pressure for the brake. A braking force holding device that is interposed in the passage and holds the braking force at that time by closing the passage,
A vehicle start assist device having a control device for controlling operation and release of the braking force holding device, comprising: accelerator pedal depression speed detection means for detecting an accelerator pedal depression speed; After the operation, when the depression of the accelerator pedal is detected, the release speed of the braking force holding device is made variable according to the speed of the depression of the accelerator pedal.

A third aspect of the present invention is a vehicle hill start assistance device, which is interposed between an engine and a transmission and generates a predetermined creep force when the transmission is engaged, and a brake fluid pressure. A braking force holding device that is interposed in the passage and holds the braking force at that time by closing the passage,
A vehicle start assist device having a control device for controlling operation and release of the braking force holding device, comprising: an accelerator sensor for detecting an amount and a speed of depression of an accelerator pedal; Thereafter, when the depression of the accelerator pedal is detected, the release speed of the braking force holding device is made variable according to the magnitude of the depression of the accelerator pedal and the speed of the depression speed.

[0011]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS One embodiment of the present invention will be described with reference to the accompanying drawings.

FIG. 6 is a block diagram of the vehicle start assist device for a hill according to the present embodiment. As shown, a transmission 3 is connected to the engine 1 via a clutch mechanism 2. As shown in FIG. 7, the clutch mechanism 2 includes a fluid coupling 4 (a fluid coupling: including a torque converter) and a wet multi-plate clutch 5 (a speed change clutch).

The fluid coupling 4 includes a pump unit 7 connected to an output shaft 6 (crankshaft) of the engine 1, a turbine unit 9 opposed to the pump unit 7 and connected to a clutch input shaft 8,
It has a stator section 10 interposed between the turbine section 9 and the pump section 7 and a lockup section 11 for connecting and disconnecting the pump section 7 and the turbine section 9. The wet multi-plate clutch 5 includes a clutch input shaft 8 and an input shaft 12 of the transmission 3.
The connection is made during the shift operation of the transmission 3 and is made after the shift is completed.

According to the clutch mechanism 2, the engine 1
Is operated and its output shaft 6 (crankshaft) is rotated, and if the lockup portion 11 is disconnected, the clutch input shaft 8 is rotated via the fluid coupling 4 and the lockup portion 11 is connected. In this case, the clutch input shaft 8 rotates integrally with the engine output shaft 6. When the wet multi-plate clutch 5 is disengaged, the rotation of the clutch input shaft 8 is not transmitted to the input shaft 12 of the transmission 3, and when the wet multi-plate clutch 5 is connected, the clutch input shaft 8 The rotation is transmitted to the input shaft 12 of the transmission 3.

The transmission 3 has an input shaft 12, an output shaft 13 arranged coaxially with the input shaft 12, and a sub shaft 14 arranged parallel to these. The input shaft 12 is provided with an input main gear 15. The output shaft 13 has a first-speed main gear 16,
2nd speed main gear 17, 3rd speed main gear 18, 4th speed main gear 19
, And a reverse main gear 20 are pivotally supported, and a 6-speed main gear 21 is fixedly provided. On the countershaft 14,
The input sub gear 22 meshing with the input main gear 15, the first speed sub gear 23 meshing with the first speed main gear 16, the second speed sub gear 24 meshing with the second speed main gear 17, and the third speed main gear 18 meshing. A third speed auxiliary gear 25, a fourth speed auxiliary gear 26 meshing with the fourth speed main gear 19, and a reverse auxiliary gear 28 meshing with the reverse main gear 20 via an idle gear 27, respectively. A 6-speed auxiliary gear 29 that meshes with the 6-speed main gear 21 is pivotally supported.

According to the transmission 3, the sleeve 31 is spline-engaged with the hub 30 fixed to the output shaft 13.
Is spline-engaged with the dog 32 of the reverse main gear 20, the output shaft 13 rotates reversely, and the sleeve 31
Is engaged with the dog 33 of the first speed main gear 16 by spline.
The output shaft 13 rotates at the first speed. And the output shaft 13
When the sleeve 35 spline-engaged with the hub 34 fixed to the spline is meshed with the dog 36 of the second speed main gear 17, the output shaft 13 rotates at the second speed and the sleeve 3
When the gear 5 is spline-engaged with the dog 37 of the third speed main gear 18, the output shaft 13 rotates at a speed equivalent to the third speed.

The hub 38 fixed to the output shaft 13
The sleeve 39, which is spline-engaged with the
When the spline meshes with the dog 40 of No. 9, the output shaft 13
When the sleeve 39 is splined with the dog 41 of the input main gear 15, the output shaft 13 rotates at the fifth speed (direct connection). When the sleeve 43 spline-engaged with the hub 42 fixed to the sub shaft 14 is spline-engaged with the dog 44 of the sixth speed sub gear 29, the output shaft 13 rotates at the sixth speed.

The above sleeves 31, 35, 39, 43
Is operated by a shift lever 45 shown in FIG. 6 in the cab via a shift fork and a shift rod (not shown). At this time, during operation of each of the sleeves 31 and the like, the wet-type multi-plate clutch 5 is disengaged so that a shift can be performed. It has become. In addition, each sleeve 31, 35, 39, 43 and dog 32, 3
A synchronizing mechanism (not shown) is provided between 3, 3, 37, 40, 41, and 44.

As shown in FIG. 6, in the transmission 3, the gear is neutral (each sleeve 31, 35, 39, 43 is attached to any dog 32, 3) based on the position of the shift rod.
3, 36, 37, 40, 41, and 44 are also provided with a neutral sensor 46 for detecting that the splines are not engaged. This neutral sensor 4
Numeral 6 designates a gear-in sensor 46 for detecting the presence or absence of a gear-in of the transmission 3.

The transmission 3 is provided with a vehicle speed sensor 47 as shown in FIGS. The vehicle speed sensor 47 calculates the vehicle speed based on the rotation speed (rpm) of the output shaft 13 of the transmission 3. As shown in FIG. 6, the engine 1 is provided with an engine sensor 48 for detecting whether or not the engine 1 is in an operating state. The engine sensor 48 detects whether or not the engine 1 is in operation based on an output from an ACG (alternating current generator) driven by a crankshaft via a belt or a gear.

The parking brake (side brake) is provided with a parking brake sensor 49 for detecting whether or not the parking brake is applied. The parking brake sensor 49 includes, for example, a limit switch that is turned on when the parking brake lever 50 is rotated by a predetermined angle.

The brake pedal 51 is provided with a brake sensor 52 for detecting depression of the brake pedal 51. The brake sensor 52 may be, for example, a limit switch that is turned on when the brake pedal 51 is depressed at a predetermined angle, or the internal pressure of a brake fluid pressure passage 60 described later has become equal to or higher than a predetermined pressure (0.5 kg / cm ² or the like). A pressure switch that is turned on at the time may be used. The turning on of the brake sensor 52 is linked with the lighting of the stop lamp.

The accelerator pedal 53 is provided with an accelerator sensor 54 for detecting the opening amount and the stepping speed of the accelerator pedal 53. The accelerator sensor 54 is
For example, the opening degree (%) of the accelerator pedal 53 is detected at predetermined time intervals (64 msec), and the control unit 56 differentiates it with time to calculate the stepping speed (% / 64 msec).

In the cab, an HSA release switch 5 for releasing the operation of the vehicle start assist device (HSA) is provided.
5 are provided. When the HSA release switch 55 is turned on, the HSA does not operate and the same behavior as a normal vehicle not equipped with the HSA comes to be exhibited.

As shown in FIG. 6, the clutch mechanism 2
Is provided with an engine rotation sensor 64 for detecting the rotation speed of the engine 1. The engine rotation sensor 64
As shown in FIG. 7, the rotational speed of the pump unit 7 connected to the output shaft 6 (crankshaft) of the engine 1 is detected, and the rotational speed of the engine 1 is detected. The sensors and switches described above are connected to the control unit 56 as shown in FIG.
(Controller).

A master cylinder 57 operated by the brake pedal 51 is connected to the brake pedal 51, and a wheel cylinder 59 for operating the brake is connected to the brake of the wheel (wheel) 58. The master cylinder 57 and the wheel cylinder 59 are connected through a fluid pressure passage 60. In the fluid pressure passage 60,
A braking force holding valve 61 that holds the braking force at that time by closing the passage 60 and releases the braking force by opening the passage 60 is provided to be openable and closable.

The braking force holding valve 61 is opened and closed in response to a command from the control unit 56 as described later. Control unit 56
Operates the HSA, that is, closes the braking force holding valve 61 according to the flow shown in FIG. That is, FIG. 1 shows the HSA operating condition (the valve closing condition of the braking force holding valve 61).

First, in step 1, it is determined whether the vehicle speed is equal to or less than 0.5 km / h. This determination is for detecting whether the vehicle is substantially stopped or not, and is made based on the output from the vehicle speed sensor 47 shown in FIGS. Vehicle speed
If not below 0.5Km / h, go to the end and the vehicle speed is 0.5Km / h
If so, go to step 2. This is because the operation of the HSA is based on the premise that the vehicle stops.

In step 2, it is determined whether the deceleration immediately before the stop is smaller than a predetermined value. This determination is for detecting whether or not the wheel 58 is locked by the brake, and is performed by differentiating the output from the vehicle speed sensor 47 with time. If the deceleration is not small, that is, if the deceleration is large, the wheel 58 may be locked even if the vehicle speed sensor 47 detects the vehicle speed of 0.5 km / h or less in step 1;
The operation proceeds to the end without operating the SA. If the deceleration is small, the operation proceeds to step 3.

In step 3, it is determined whether the brake pedal 51 has been depressed. This judgment is made by the brake sensor 5
2 (a limit switch provided in the brake pedal 51) and a pressure switch (not shown) provided in the brake fluid pressure passage 60 (set pressure = 0.5 kg / cm ² or the like). If the brake pedal 51 is not depressed, the process proceeds to the end. If the brake pedal 51 is depressed, the process proceeds to step 4. That is, the HSA does not operate unless the brake pedal 51 is depressed.

In step 4, it is determined whether the parking brake is off. This determination is made by the parking brake sensor 49 provided on the parking brake lever 50.
Is made based on the output of If the parking brake is not off, that is, if the parking brake is on, the procedure goes to the end. If the parking brake is off, the procedure goes to step 5. This is because if the parking brake is on, the vehicle can be stopped without operating the HSA.

In step 5, the HSA release switch 55
Is turned off. This determination is made based on the output of the HSA release switch 55 provided in the driver's cab. If the HSA release switch 55 is not off, that is, if it is on, the process proceeds to the end. . It reflects the driver's intention. That is, even if the operating conditions of the HSA are prepared, when the driver turns on the HSA release switch 55 because he does not want to operate the HSA, the HSA does not operate.

In step 6, it is determined whether the engine 1 is operating. This determination is made based on the engine sensor 48 (A
CG output sensor). If the engine 1 is not operating, the process proceeds to the end. If the engine 1 is operating, the process proceeds to step 7. This is because if the engine 1 is stopped, there is no need to prepare for restart after stopping and there is no need to operate the HSA.

In step 7, a failure diagnosis of the present system is performed to determine whether the system is normal. This failure diagnosis is performed by each of the sensors 46, 47, 48, 49, 5 shown in FIG.
Whether or not 2, 54, 55, etc. are normal is detected and performed. If abnormal, the process proceeds to the end, and if normal, the process proceeds to step 8. This is because normal operation is impossible even if the HSA is to be activated when the system is abnormal.

In step 8, it is determined whether the gear is neutral. This determination is made based on the output from the neutral sensor (gear-in sensor) 46 of the transmission 3.
If the gear is neutral, go to step 10 and select HS
A is operated (the braking force holding valve 61 is closed). As a result, the braking force generated when the brake pedal 51 is depressed at that time is maintained even after the brake pedal 51 is released, and the stop of the vehicle is maintained.

At step 8, if the gear is not neutral, that is, if the gear is in the in-state, the routine proceeds to step 9. In step 9, it is determined whether the accelerator pedal 53 is in the idle position. This determination is made based on the output of the accelerator sensor 54. If the accelerator pedal 53 is in the idle position, the routine proceeds to step 10 where the HSA is operated (the braking force holding valve 61 is closed). This allows
If the accelerator pedal 53 is in the idle position even in the gear-in state, the braking force generated when the brake pedal 51 is depressed at that time is maintained even after the brake pedal 51 is released, and the stop of the vehicle is maintained. .

Here, the fact that the vehicle stops in the gear-in state means that the vehicle is stopped with the foot brake force exceeding the creep force, and the foot brake stepping pressure (pressure in the brake fluid pressure passage 60) is shown in FIG. Braking force holding valve 6 shown
By holding the valve 1 by closing it, the vehicle can be prevented from starting to move due to creep force.

On the other hand, at step 9, the accelerator pedal 5
If 3 is not the idle position, that is, if the accelerator pedal 53 is depressed, the process proceeds to the end without operating the HSA. When the accelerator pedal 53 is depressed, it is considered that the driver intends to start, and the HSA
It is not necessary to operate the.

Steps 1 to 7 described above are all YES, and the state of YES in step 8 or 9 is 0.
When 5 seconds or more have elapsed, the control unit 56 sets the braking force holding valve 6
1 is closed, and the closing (operation of the HSA) of the braking force holding valve 61 is held until the HSA release condition described below is satisfied.

FIG. 2 shows the HSA release condition (the braking force holding valve 61).
).

First, at step 21, it is determined whether the parking brake is on. This determination is made based on the output of the parking brake sensor 49. If the parking brake is on, go to step 27,
HSA is released by on / off control (braking force holding valve 61
Is opened). H if parking brake is on
This is because the vehicle can be stopped even if the SA is released.

Here, in step 27, the braking force holding valve 61, which has been closed up to that time, is opened at once, and the HSA
Is released at once. This is because if the parking brake is on, the vehicle can be stopped even if the HSA is released at a stretch in the gear-in state. Therefore, step 2
At 7, the HSA is controlled to be turned on and off. On the other hand, if the parking brake is not on, the process proceeds to step S22.

In step 22, it is determined whether the vehicle speed is equal to or higher than 4.5 km / h. This determination is made based on the output from the vehicle speed sensor 47. If the vehicle speed is equal to or higher than 4.5 km / h, the routine proceeds to step 27, in which the HSA is released at a stretch (the braking force holding valve 61 is opened at a stretch). 4.5K speed
If the speed is not less than m / h, it is not necessary to generate the braking force by the HSA. On the other hand, if the vehicle speed is lower than 4.5 km / h, the routine proceeds to step 23.

In step 23, the HSA release switch 5
It is determined whether 5 is on. This determination is made based on the output of the HSA release switch 55 provided in the cab.
If the HSA release switch 55 is on, the process proceeds to step 27, where the HSA is released at once (the braking force holding valve 61).
Is opened at once). It reflects the driver's intention. On the other hand, if the HSA release switch 55 is off, the process proceeds to step 24.

In step 24, it is determined whether the gear is neutral. This determination is made based on the output from the neutral sensor (gear-in sensor) 46 of the transmission 3. If the gear is in neutral, the process goes to the end and the HSA is not released. The fact that the gear is neutral means that the driver does not intend to start the vehicle and the operation of the HSA should be held (the closing of the braking force holding valve 61 should be held).

On the other hand, if the gear is not neutral, that is, if it is in the gear-in state, the routine proceeds to step 25. Step 25
Then, the accelerator sensor 54 determines whether the accelerator pedal 53 is depressed. If the accelerator pedal 53 is depressed for a certain degree or more (for example, 3% or more), the flow goes to step 26 and the HSA is released by the duty control.

The duty control in step 26 will be described with reference to FIGS.

FIG. 3 is a map showing the relationship between the opening amount of the accelerator pedal 53 and the basic duty output A. The opening amount (%) of the accelerator pedal 53 is detected every 64 msec by the accelerator sensor shown in FIG. Then, based on the detected accelerator opening (%), the basic duty output A is determined according to the map shown in FIG.
That is, the basic duty output A is 100% if the accelerator opening amount is within the range of the play of the accelerator pedal 53.
(HSA hold), and 0% (HSA release) if the accelerator opening is 50% or more, and if the accelerator opening is more than the play range of the pedal 53 and less than 50%, the accelerator opening increases. Decreasing. Note that the decreasing tendency may not be a straight line.

FIG. 4 is a map showing the relationship between the depression speed of the accelerator pedal 53 and the corrected duty output B.
The depression speed (% / 64 msec) of the accelerator pedal 53 is calculated by differentiating the accelerator opening amount (%) detected by the accelerator sensor 54 every 64 msec with the control unit 56 over time. Then, the detected accelerator depression speed (% / 64mse
Based on c), the correction duty output B is determined according to the map shown in FIG. In other words, the correction duty output B is approximately 20% when the accelerator stepping speed is 0 (% / 64 msec), and thereafter, the accelerator stepping speed (% / 64
msec), the output B increases. In addition,
The increasing trend need not be a straight line.

The basic duty output A and the corrected duty output B obtained based on FIGS. 3 and 4 are calculated by the control unit 56 in the equation shown in FIG.
A− (B + B before 64 msec)), and the output duty (%) is calculated. According to this equation, the output duty is calculated from the basic duty output A determined on the map of FIG. 3 according to the accelerator opening amount at that time to the correction duty determined on the map of FIG. 4 according to the accelerator depression speed at that time. The output B is subtracted, and the correction duty output B determined by the map in FIG. 4 is further subtracted according to the accelerator depression speed 64 msec before, which is calculated. When the calculated output duty is lower than 0%, the output is set to 0%.

Then, according to the calculated output duty (%), the braking force holding valve 61 (electromagnetic valve) shown in FIG.
Is duty controlled.

For example, if the accelerator opening amount is 50% or more, the basic duty output A becomes 0% in the map of FIG.
Therefore, no matter what the accelerator pedal depressing speed is in the map of FIG. 4, that is, no matter how many correction duty outputs B, the output duty becomes 0% according to the equation of FIG. You. Therefore, when the driver depresses the accelerator pedal 53 to a large extent, for example, at the time of starting when the vehicle stops on an uphill, the braking force holding valve 61 is quickly opened fully and the engine speed is increased by depressing the accelerator pedal 53. Increased creep power allows the vehicle to start quickly without slipping.

When the accelerator opening amount is not less than the play and less than 50%, for example, when the basic duty output A is 50% in the map of FIG. 3, the accelerator pedal 53 is quickly depressed and the accelerator pedal 53 is depressed quickly in the map of FIG. Stepping speed is 7
If it is 0 (% / 64 msec), the output duty becomes 0% according to the equation in FIG. 5, and the braking force holding valve 61 is quickly and fully opened. Therefore, the intention of the driver (the intention to quickly depress the accelerator pedal 53 and start quickly) is reflected. For example, when the driver depresses the accelerator pedal 53 quickly at the time of starting when the vehicle stops on an uphill, for example, the braking force holding valve 61 is quickly fully opened and the engine speed rises due to the quick depression of the accelerator pedal 53. Increased creep power allows the vehicle to start quickly without slipping.

When the accelerator opening amount is not less than the play and less than 50%, for example, when the basic duty output A is 50% in the map of FIG. 3, the accelerator pedal 53 is gently depressed, and for example, When the accelerator stepping speed is 10 (% / 64 msec), the output duty becomes about 30% according to the equation in FIG. 5, and the braking force holding valve 61 is gradually opened fully. Therefore, the driver's intention (the intention to gradually depress the accelerator pedal 53 and start slowly) is reflected. For example, when the driver depresses the accelerator pedal 53 gently at the time of starting when the vehicle stops on a congested road or at the time of starting when stopping on a downhill, the braking force holding valve 61 is gradually opened fully and creep is performed. Since the power does not increase rapidly, the vehicle starts slowly.

In FIG. 4, the accelerator depression speed is 0.
The reason why the correction duty output at (% / 64 msec) is set to a predetermined percentage (about 20%) instead of 0% is that the output duty calculated by the equation in FIG. 5 even when the opening amount of the accelerator pedal 53 is constant. This is for reducing the drag caused by the HSA by reducing the HSA to the direction in which the HSA is released. In FIG. 5, the reason why B before 64 msec as well as B from A is reduced is that the calculated output duty is quickly reduced and the HSA is released. Note that B before 128 msec from A may be further reduced.

In this embodiment, a two-shaft manual transmission as shown in FIG. 7 is used for the transmission 3, and the wet multi-plate clutch 5 and the fluid coupling 4 are used for the clutch mechanism 2.
However, the present invention is not limited to this, but instead of the two-axis manual transmission, the transmission 3 employs a planetary gear type automatic transmission, and the clutch mechanism 2 does not include the wet multi-plate clutch 5 and employs a fluid. Only the joint 4 may be employed. In short, the present invention provides a fluid coupling 4
The present invention is concerned with the problem of creep force caused by the use of the transmission 3, and the transmission 3 may be any mechanism (belt type CVT, half toroid CVT, etc.) as long as it has the fluid coupling 4.

[0057]

As described above, according to the vehicle start assist system for a vehicle according to the present invention, when the HSA is released, the opening speed of the braking force holding valve is controlled in accordance with the depression of the accelerator pedal. Therefore, the driver's intention via the accelerator pedal can be reflected on the opening speed of the braking force holding valve, and the vehicle can be controlled to start or stop slowly. Therefore, for example, it is possible to avoid the vehicle from rolling down when starting on an uphill or sudden starting when starting on a congested road or downhill.

[Brief description of the drawings]

FIG. 1 is a flowchart showing operating conditions of a vehicle start assist device (HSA) according to an embodiment of the present invention.

FIG. 2 is a flowchart showing conditions for releasing the HSA.

FIG. 3 is a map diagram showing a relationship between an opening amount of an accelerator pedal and a basic duty output A;

FIG. 4 is a map diagram showing a relationship between an accelerator pedal depression speed and a corrected duty output B;

FIG. 5 is an explanatory diagram showing a calculation formula for calculating an output duty from a basic duty output A and a correction duty output B.

FIG. 6 is a schematic diagram showing the HSA system.

FIG. 7 is an explanatory diagram showing a transmission and a clutch mechanism of the HSA.

FIG. 8 is a flowchart showing operating conditions of an HSA under development by the present inventors.

FIG. 9 is a flowchart showing HSA release conditions under development by the inventor.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Engine 3 Transmission 4 Fluid coupling 46 Gear-in sensor (neutral sensor) 53 Accelerator pedal 54 Accelerator sensor 56 Control unit 60 Fluid pressure passage 61 Braking force holding valve

Claims (3)

[Claims] 1. A fluid coupling which is interposed between an engine and a transmission and generates a predetermined creep force when the transmission is engaged, and a brake which is interposed in a fluid pressure passage of a brake and closes the passage to close the passage. What is claimed is: 1. A hill start assist device for a vehicle, comprising: a braking force holding device for holding a force; and a control device for controlling operation and release of the braking force holding device, wherein an accelerator opening amount detecting means for detecting an amount of depression of an accelerator pedal. A vehicle characterized in that when the depression of an accelerator pedal is detected after the operation of the braking force holding device, the release speed of the braking force holding device is made variable according to the magnitude of the accelerator opening. Slope start assist device. 2. A fluid coupling interposed between the engine and the transmission for generating a predetermined creep force when the transmission is engaged, and a brake interposed in a fluid pressure passage of the brake for closing the passage to close the passage. A hill start assist device for a vehicle, comprising: a braking force holding device that holds a force; and a control device that controls the operation and release of the braking force holding device, the accelerator pedal depression speed detection detecting an accelerator pedal depression speed. Means for deactivating the braking force holding device according to whether the accelerator pedal is depressed after the operation of the braking force holding device or not. Slope start assist device for vehicles. 3. A fluid coupling interposed between the engine and the transmission to generate a predetermined creep force when the transmission is engaged, and a brake interposed in a fluid pressure passage of the brake to close the passage so as to close the brake. A hill start assist device for a vehicle, comprising: a braking force holding device that holds a force; and a control device that controls operation and release of the braking force holding device, wherein an accelerator sensor detects an amount and speed of depression of an accelerator pedal. When the depression of the accelerator pedal is detected after the operation of the braking force holding device, the release speed of the braking force holding device is determined according to the magnitude of the depression amount of the accelerator pedal and the speed of the depression speed. A vehicle slope start assist device characterized by being variable.