JP2004148861A - Vehicle start auxiliary device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a vehicle start auxiliary device coexistent with a mechanical automatic transmission. <P>SOLUTION: This vehicle start auxiliary device includes a brake pressure retaining valve 17 to keep a service brake in a braking state, a clutch stroke sensor 5 to directly detect the clutch stroke of a mechanical clutch 2, and a start auxiliary control unit 16 to control the brake pressure retaining valve 17 so that the service brake is released from the braking state based on the clutch stroke detected by the clutch stroke sensor 5. <P>COPYRIGHT: (C)2004,JPO

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to a vehicle start assist device, and more particularly to a technique for coexisting with a mechanical automatic transmission.
[0002]
[Prior art]
The vehicle start assist device is a device that temporarily holds the service brake in a braking state even when the brake pedal is released, in order to reduce the driver's labor when starting on a hill, congestion or waiting for a traffic light. is there. As disclosed in Japanese Patent Application Laid-Open No. H11-343888 (Patent Document 1), this device detects a clutch stroke with a clutch pedal stroke sensor provided on a clutch pedal, and detects the detected clutch stroke in advance. When the set predetermined value is reached, the service brake is released from the braking state. In vehicles equipped with this device, even if the brake pedal is released, the service brake is held in the braking state until the clutch is engaged. There is no need to step on the brake pedal, and there is no need to continue to depress the brake pedal during traffic jams or waiting for traffic lights.
[0003]
[Patent Document 1]
JP-A-11-343888
[Problems to be solved by the invention]
In recent years, particularly in commercial vehicles such as trucks, automatic transmissions using a mechanical clutch have been widely used in recent years. This automatic transmission changes gears by automatically connecting and disconnecting a mechanical clutch and switching gears in response to an operation of a shift lever without a driver operating a clutch. . Therefore, in a vehicle provided with such an automatic transmission, even when starting, the mechanical clutch is automatically connected in accordance with the operation of the shift lever, so that the driver does not operate the clutch pedal. Automatic start that can start is possible.
[0005]
If a vehicle equipped with such an automatic transmission is provided with a start assist device, the clutch pedal is not operated at the time of automatic start, so that a clutch stroke is not detected by the clutch pedal stroke sensor. As a result, there is a problem that the service brake is not released from the braking state and cannot start.
[0006]
Accordingly, the present invention has been made in view of the above-described conventional problems, and in a vehicle having a mechanical automatic transmission, the service brake is released from the braking state even at the time of automatic start, so that the mechanical automatic transmission is It is an object of the present invention to provide a vehicle start assist device capable of assisting start in coexistence with the vehicle.
[0007]
[Means for Solving the Problems]
Therefore, the invention according to claim 1 is a brake holding means for holding a service brake in a braking state, a clutch stroke detecting means for directly detecting a clutch stroke of a mechanical clutch, and a clutch detected by the clutch stroke detecting means. And a brake release control means for controlling the brake holding means such that the service brake is released from the braking state based on a stroke.
[0008]
According to this configuration, the service brake held in the braking state is released based on the clutch stroke of the mechanical clutch directly detected by the clutch stroke detecting means, so that the mechanical clutch can be operated without operating the clutch pedal. The service brake is automatically released when the vehicle starts even in a vehicle equipped with an automatic transmission that is connected and disconnected.
[0009]
The invention according to claim 2, wherein the brake release control means is configured to release the service brake from the braking state when the clutch stroke detected by the clutch stroke detection means reaches a predetermined value. It is characterized in that the holding means is controlled.
[0010]
According to this configuration, the service brake is released from the braking state when the clutch stroke directly detected by the clutch stroke detecting unit reaches a predetermined value, so that an increase in the control load of the brake release control unit can be suppressed.
[0011]
According to a third aspect of the present invention, there is provided a determining means for determining whether or not the mechanical clutch is connected based on an operation of a clutch pedal, and the brake release control means is provided based on a determination result of the determining means. , Wherein the predetermined value is changed.
[0012]
According to this configuration, the predetermined value is changed depending on whether or not the mechanical clutch is connected based on the operation of the clutch pedal, so that the automatic clutch is started or when the clutch pedal is slowly operated to start manually. In any case where the connection speeds of the clutches are different, the braking state of the service brake is appropriately released.
[0013]
The invention according to a fourth aspect is characterized in that an accelerator opening detecting means for detecting an accelerator opening is provided, and the brake release control means changes the predetermined value based on the accelerator opening.
[0014]
According to this configuration, the predetermined value is changed based on the accelerator opening. For example, when the accelerator opening is large, the braking state is released with the half-clutch weaker than when the accelerator opening is small. By setting the predetermined value as described above, the braking state is released earlier, and when the accelerator opening is small, the braking state is released later.
[0015]
The invention according to claim 5 is provided with starting gear position detecting means for detecting a gear position at the time of starting, wherein the brake release control means changes the predetermined value based on the starting gear position. Features.
[0016]
According to such a configuration, the predetermined value is changed based on the gear stage at the time of starting. For example, when the starting gear stage is a high speed stage, the half clutch is weaker than when the starting gear stage is a low speed stage. By setting a predetermined value so that the service brake is released from the braking state, the braking state is released earlier, and the braking state is released later when the starting gear is at a low speed.
[0017]
BEST MODE FOR CARRYING OUT THE INVENTION
Hereinafter, the present invention will be described in detail with reference to the accompanying drawings.
[0018]
FIG. 1 shows a configuration of a vehicle provided with the start assist device of the present invention.
[0019]
A mechanical transmission (hereinafter, referred to as “transmission”) 3 is attached to the engine 1 via a mechanical clutch (hereinafter, referred to as “clutch”) 2.
[0020]
An output shaft of a clutch booster 4 as a clutch driving actuator is connected to the clutch 2 and a clutch stroke sensor 5 (clutch stroke detecting means) for directly detecting the stroke is attached.
[0021]
On the other hand, the transmission 3 is provided with a position sensor 6 (starting gear position detecting means) for detecting a gear position.
[0022]
In the cab, an accelerator opening sensor 8 (accelerator opening detecting means) for detecting the amount of depression of an accelerator pedal 7, a clutch pedal stroke sensor 10 for detecting the amount of depression of a clutch pedal 9, and a shift to the transmission 3. A shift lever 11 for inputting an instruction is provided.
[0023]
The automatic transmission control unit 12 has a built-in microcomputer, and receives a shift instruction from the shift lever 11 while receiving detection signals from the clutch stroke sensor 5, the position sensor 6, and the accelerator opening sensor 8, and performs a transmission operation. In addition to controlling the operation of the transmission driving actuator 13 connected to the clutch 3, the transmission and disconnection command is sent to the clutch booster 4 to cause the clutch 2 to be disconnected and connected. Note that the clutch booster 4 also operates based on the operation of the clutch pedal 9 and causes the clutch 2 to be connected and disconnected.
[0024]
Further, the automatic transmission control unit 12 operates the transmission drive actuator so that the starting gear is set to a low speed when the vehicle is in a loaded state, and the starting gear is set to a high speed when the vehicle is idle. 13 is controlled. In order to detect whether the vehicle is in a loaded state or in an empty state, for example, a load detecting means for detecting a load acting on an axle or a bed may be provided.
[0025]
In a pipe that connects a brake valve 14 and a brake booster 15 of a service brake (hereinafter, referred to as a “brake”) of a vehicle, a pipe in the pipe is normally opened, and a start assistance control unit 16 (brake release control means, determination A brake pressure holding control valve 17 (brake holding means) for shutting off the pipe line in the pipe based on the brake pressure holding command from the means is interposed.
[0026]
The start assist control unit 16 has a built-in microcomputer, and can receive information (clutch stroke, gear position, accelerator opening) from the automatic transmission control unit 12 by CAN (Controller Area Network) communication.
[0027]
When the clutch pedal 9 is depressed or the gear position of the transmission 3 is in the neutral position, the start assist control unit 16 depresses the brake pedal 18 connected to the brake valve 14 for a predetermined time or more. A brake pressure holding command is sent to the brake pressure holding control valve 17 so that the brake pressure is maintained even if the depression of the brake pedal is released. As a result, the pipeline in the pipe is cut off, the brake pressure is maintained, and the brake is maintained in the braking state.
[0028]
When the clutch stroke detected by the clutch stroke sensor 5 reaches the release value (predetermined value) via the automatic speed change control unit 12, the start assist control unit 16 sends the brake pressure holding control valve 17 to the brake pressure holding control valve 17. The transmission of the brake pressure holding command is stopped. As a result, the pipeline in the pipe is opened, the brake pressure is released, and the braking state of the brake is released.
[0029]
A first embodiment of a control method in the start assist control unit 16 of the present invention will be described. When a signal indicating the amount of depression of the clutch pedal 9 is transmitted from the clutch pedal stroke sensor 10, the start assist control unit 16 determines that the clutch 2 is operated manually based on the operation of the clutch pedal 9, and the clutch is started. When a signal indicating the amount of depression of the clutch pedal 9 is not transmitted from the pedal stroke sensor 10 and a signal indicating the clutch stroke is transmitted from the clutch stroke sensor 5, it is determined that the vehicle is automatically started.
[0030]
Then, as shown in FIG. 2, the start assist control unit 16 sets the release value to a manual start release value when it is determined that the vehicle is a manual start, and automatically sets the release value when it is determined that the vehicle is an automatic start. Set to the start release value.
[0031]
The automatic start release value is set to a value larger than the manual start release value. When the clutch stroke is large, the clutch 2 is in a disconnected state, and when the clutch stroke is small, the clutch 2 is in a connected state. Thus, at the time of automatic start, the brake is released from the braking state with the half clutch weak.
[0032]
When the clutch is disengaged from the disengaged state in order to start the vehicle by operating the start assist device having the above configuration, the driver does not suddenly connect the clutch at the time of manual start. As the clutch is gently connected, the clutch stroke gradually decreases as compared to the automatic start, but the manual start release value is smaller than the automatic start release value, so the clutch stroke is delayed and manual release is released. Reaches the value. As a result, the brake pressure is released slowly, the time during which the brake is in the braking state in the half-clutch state is extended, and the brake pressure is released in a state where the clutch 2 is connected and the driving force is sufficiently ensured. The clutch is connected in a short time while preventing reverse running when starting on a slope. On the other hand, at the time of automatic start, due to the characteristics of the automatic transmission, the clutch stroke is sharply reduced to the clutch stroke to which the clutch is connected, but since the release value at the time of automatic start is larger than the release value at the time of manual start, the clutch stroke is automatically The start release value is reached, and the load on the clutch is reduced.
[0033]
In the second embodiment of the control content of the start assist control unit 16 of the present invention, the release value is changed based on the accelerator opening detected by the accelerator opening sensor 8 via the automatic transmission control unit 12. The release value is calculated using a map as shown in FIG. FIG. 3 shows a release value corresponding to the accelerator opening. When the accelerator opening is large, the release value is large, and when the clutch opening is small, the release value is small.
[0034]
As a result, when the accelerator opening is large, the release value is large, so that when the clutch stroke is large, the brake pressure is released. Therefore, the brake is quickly released from the braking state. This is presumed that when the accelerator opening is large, the driver intends to make a sudden start, and thus the vehicle is quickly started by releasing the brake early. .
[0035]
On the other hand, when the accelerator opening is small, the release value is small, so the brake pressure is released when the clutch stroke is small. Therefore, the brake is released from the braking state later. This is because when the accelerator opening is small, the engine torque is small, and thus the brake is released late, and the brake is released with sufficient driving force. In this case, it is difficult to reverse.
[0036]
In the third embodiment of the control content of the start assist control unit 16 of the present invention, the release value is changed based on the gear at the start detected by the position sensor 6 via the automatic transmission control unit 12. The release value is calculated using a map as shown in FIG. FIG. 4 shows the release value corresponding to the starting gear stage. When the starting gear stage is a high speed stage, the release value is large, and when the starting gear stage is a low speed stage, the release value becomes small. I have.
[0037]
As a result, when the starting gear is a high speed, the release value is large, so that the brake pressure is released when the clutch stroke is large. Therefore, the brake is quickly released from the braking state. It should be noted that when the starting gear is a high speed stage, the vehicle is in an idle state, so that a large engine torque is not required. For this reason, even if the brake is released early when starting on a slope, for example, the vehicle is unlikely to run backward.
[0038]
On the other hand, when the starting gear is the low speed, the release value is small, so that the brake pressure is released when the clutch stroke is small. Therefore, the brake is released late. This is because when the starting gear is at a low speed, the vehicle is in a loaded state, so a large engine torque is required, and when the brake is released with the clutch 2 fully connected, for example, when starting on a hill, Prevents the vehicle from running backwards.
[0039]
In each of the first to third embodiments described above, since both the clutch stroke sensor 5 and the clutch pedal stroke sensor 10 are provided, even if the CAN communication becomes abnormal, the clutch pedal stroke sensor Since the start assist can be performed based on the depression amount of the clutch pedal 9 detected by 10, the reliability of the start assist device is improved.
[0040]
In addition, the control contents of the start-up assist control unit 16 described in the first to third embodiments described above are not limited to being implemented alone, and may be implemented in any combination or in all. Good.
[0041]
【The invention's effect】
As described above, according to the first aspect of the invention, even in a vehicle equipped with an automatic transmission in which the clutch is connected without operating the clutch pedal, the service brake is automatically released at the time of starting, and the vehicle is started. Since assistance is provided, a starting assistance device that coexists with a mechanical automatic transmission is enabled.
[0042]
According to the second aspect of the invention, an increase in the control load in the brake release control means is suppressed.
[0043]
According to the third aspect of the present invention, the service is provided in any case where the clutch connection speed is different, such as at the time of automatic start by the automatic transmission or at the time of manual start in which the clutch pedal is slowly operated to start. The braking state of the brake is appropriately released, and the vehicle starts smoothly. In addition, since it is automatically determined whether the vehicle is to be automatically started or manually started, the equipment can be shared even in a vehicle that can be automatically started or manually started.
[0044]
According to the invention described in claim 4, for example, by setting the predetermined value so that when the accelerator opening is large, the half-clutch is weaker than when the accelerator opening is small, and the braking state is released, The brake state is released early, and when the accelerator opening is small, the brake state is released later. Thus, when the accelerator opening is large, the vehicle can be started quickly, and when the accelerator opening is small, the brake is released in a state where the driving force is sufficiently secured, and it is difficult for the vehicle to run backward even when starting on a slope.
[0045]
According to the fifth aspect of the present invention, for example, the clutch stroke is set so that when the starting gear is a high gear, the braking state is released with a half clutch weaker than when the starting gear is a low gear. As a result, the vehicle is quickly released from the braking state, and is later released from the braking state when the starting gear is at the low speed. As a result, when the starting gear is a high speed, the vehicle is in an idle state, so it is difficult for the vehicle to run backward even when starting on a slope, and when the starting gear is a low speed, the braking is performed with sufficient driving force secured. Is released, so it is difficult to run backwards even when starting on a slope.
[Brief description of the drawings]
FIG. 1 is a configuration diagram of a vehicle provided with an automatic transmission start assist device of the present invention. FIG. 2 is a graph showing a transition of a clutch stroke in automatic start and manual start. FIG. 3 is a diagram showing a release value corresponding to an accelerator opening. FIG. 4 is an explanatory diagram of a map shown. FIG. 4 is an explanatory diagram of a map showing a release value corresponding to a start gear position.
2 Mechanical clutch 5 Clutch stroke sensor 6 Position sensor 8 Accelerator opening sensor 9 Clutch pedal 16 Start assistance control unit 17 Brake pressure holding valve

Claims (5)

Brake holding means for holding the service brake in a braking state;
Clutch stroke detecting means for directly detecting a clutch stroke of a mechanical clutch,
Brake release control means for controlling the brake holding means such that the service brake is released from the braking state based on the clutch stroke detected by the clutch stroke detection means;
A starting assistance device for a vehicle, comprising: The brake release control means controls the brake holding means so that the service brake is released from the braking state when the clutch stroke detected by the clutch stroke detection means reaches a predetermined value. The vehicle start assist device according to claim 1, wherein: Determining means for determining whether the mechanical clutch is connected based on operation of a clutch pedal,
The vehicle start assist device according to claim 2, wherein the brake release control unit changes the predetermined value based on a result of the determination by the determination unit. Accelerator opening detecting means for detecting the accelerator opening is provided,
4. The vehicle start assist device according to claim 2, wherein the brake release control unit changes the predetermined value based on the accelerator opening. 5. Start gear position detecting means for detecting a gear position at the time of start is provided,
The vehicle start assist device according to any one of claims 2 to 4, wherein the brake release control means changes the predetermined value based on a gear stage at the time of the start.

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