JP2000238627A - Device for assisting start in slope - Google Patents

Abstract

PROBLEM TO BE SOLVED: To eliminate any adjusting work, and to conduct stable control all the time without using an exclusive switch or sensor. SOLUTION: This slope start assisting device 10 actuates a brake control valve (braking force holding means) 6 to keep a braking force when a brake pedal is actuated to stop a vehicle. In the other hand, since a position of a control rack of a fuel injection pump mounted on an engine is changed when an acceleration pedal is actuated to start the vehicle, a controller 7 inputs rack position information, engine rotation information, acceleration opening information and the like from an electronic governor controller 15, and the finish of braking force maintenance is determined using an engine load condition, an engine rotation condition, an acceleration opening changing speed and other information found by the informations hereinbefore so as to output a control signal for releasing a brake device to the brake control valve 6.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a hill start assist device which facilitates and smoothly starts a vehicle on an uphill road.

[0002]

2. Description of the Related Art When starting a vehicle on an uphill road,
The driver operates while associating the coupling states of the brake device, the accelerator pedal, and the clutch with each other, and particularly when starting a truck or the like when loading it, it is necessary to be proficient in driving technology. It is difficult for a driver who is not proficient in driving technology to smoothly start the vehicle without retreating or stopping the engine in such a situation.

Therefore, trucks and the like are equipped with a slope start assist device for easily and smoothly starting on an uphill road. This hill start assist device holds the braking force of the wheel cylinder when the vehicle is stopped by a brake operation, determines whether the clutch is disengaged or connected based on the stroke position of the clutch pedal when the vehicle starts, and when the clutch changes from the disengaged state to the engaged state. The brake is configured to be released. Further, an adjusting function for adjusting a change with time of the clutch contact (disconnection / contact) due to wear of the clutch plate or the like is provided.

[0004]

As in the prior art, a clutch stroke sensor is indispensable for determining the brake release timing based on the stroke position of the clutch pedal. In addition, clutch disconnection /
Since the proper position for switching the contact deviates from the initially set position due to the change over time, it is necessary to adjust the position by any method. As a method therefor, a switch for adjusting the contact (disengagement / contact) position of the clutch is provided, and the driver changes the set position while sensing the state of the clutch by manual operation.
Alternatively, there is a method in which a pressure switch is provided in the clutch unit and the set position is automatically moved by the wear of the clutch plate. However, any of these adjustment methods requires a dedicated switch or sensor, and furthermore, in the case of manual adjustment, the driver must make adjustments at any time, and the adjustment operation is complicated, difficult to understand, and cumbersome. There's a problem.

SUMMARY OF THE INVENTION It is therefore an object of the present invention to provide a hill start assist device which can always perform stable control without using an exclusive switch or sensor without adjustment.

[0006]

In order to achieve the above object, a hill start assist device according to the present invention comprises: an engine load state determined from control rack position information of a fuel injection pump mounted on an engine of a vehicle; Using the engine rotation state obtained from the rotation information and the value of the accelerator opening change speed obtained from the accelerator opening information, it is determined whether or not the braking force by the braking force holding means should be released, and control is performed based on this determination result. The braking force by the power holding means is released.

Here, it is determined that the engine load condition is larger on the two-dimensional map composed of the control rack position and the rack position changing speed, as the control rack position and the rack position changing speed take a larger value in the upper right of the map. The rack position change speed includes a negative area on the two-dimensional map, and the engine load state is set to three or more areas including no load from the lower left to the upper right of the map. With this configuration, the vehicle can easily and smoothly start on an uphill road,
In addition, since the determination of the release of the braking force is performed finely, malfunction of the device is suppressed.

[0008]

FIG. 1 is a view showing an embodiment of a slope start assisting apparatus according to the present invention. As shown in the figure, this slope start assist device is applied to an air brake system as a vehicle brake control device. Here, the transmission of the vehicle to which this embodiment is applied is a normal manual transmission (not shown), and the fuel supply system for supplying fuel to the engine is an electronic governor constituted by an electronic governor and a row type fuel injection pump. Controlled fuel injection pump system. The control of the fuel injection amount, the control of the fuel injection timing, the control of the fuel feed rate, and the like are performed using a computer.

As shown in FIG. 1, the air brake system includes an air tank 1, an air chamber 2 of an air brake mechanism (not shown) as a braking device, and an air passage 3 connecting the two. Be composed. A brake valve 4 ′ that opens and closes in response to depression of a brake pedal 4, a stop lamp switch (SW) 5 that operates when an air pressure is supplied to the air passage 3 and outputs a signal, A hill start assist device 10 is provided.

The hill start assist device 10 includes a brake control valve (electromagnetic valve) 6 as a braking force holding means,
A control device 7 for controlling the valve 6 is provided. When a control signal for starting the auxiliary function is supplied from the control device 7 (for example, supply of a drive current), the brake control valve 6 shuts off the air passage 3 to maintain the air pressure in the air chamber 2 and as a braking force. Maintain the braking force of
When a control signal for ending the auxiliary function is supplied from the control device 7 (for example, the drive current is cut off), the air pressure in the air chamber 2 is released to the atmosphere to release the braking force.

The control device 7 controls the stop signal (break) from the stop lamp SW5, the parking signal (park) from the parking (P) brake SW12, and the neutral signal (nu) from the shift lever neutral SW13.
t), a vehicle speed pulse signal (ve) from the vehicle speed sensor 14, a rack position signal (rack) of the control rack of the fuel injection pump, an engine speed signal (rpm), and an accelerator opening signal (accl) from the electronic governor control device 11.
Also, other signals (not shown) are input. Control device 7
Determines the start / end of the slope start assist function using these input signals, and determines the control signal (a
us) is output to the brake control valve 6.

[0012] Clutch disengagement for determining brake release time /
The determination of contact can be made based on engine-related information such as an engine-generated torque, an engine speed, and an accelerator opening. However, as the engine output increases, the tendency of the engine speed to follow the depression of the accelerator pedal tends to be delayed. Therefore, when the accelerator pedal is depressed and the engine speed changes, the clutch disconnection /
When contact is determined, the timing of the determination is delayed, and the feeling at the time of starting deteriorates.

Therefore, in the present invention, as described above, the rack position signal of the control rack of the fuel injection pump is fetched, and the intention of the driver to start the vehicle is read from the rack position signal. This is because the position of the control rack of the fuel injection pump corresponds to the depression of the accelerator pedal. Then, it is estimated from the state of change of the rack position signal that the clutch is disengaged from the disengaged state, and the brake is released. At this time, more reliable control can be performed by using the rack position and the rack position change speed.

In the estimation of clutch disconnection / engagement based on this type of engine-related information, there is a possibility that an erroneous determination (erroneous release) may occur due to a driver blowing air or operating a compressor by an air conditioner or the like. This is because changes in the rack position and engine speed at the time of idling or operation of the compressor may show changes similar to those at the start of the vehicle. Therefore, in the present invention, as will be described later, information of the accelerator opening change speed is added to the determination of the end of the auxiliary function, and a negative region of the rack position change speed is added to the two-dimensional map for determining the engine load state. , To suppress the occurrence of malfunction.

FIG. 2 is a diagram showing an example of a block configuration of the control device 7. As shown in FIG. As shown in the figure, the signal processing circuit 21 receives a rack position signal (rack) and outputs a rack as a rack position signal after signal processing and an fgack as a rack position change speed signal. Further, the idling rack position calculation circuit 22 inputs the track and outputs the idlrack position signal adltrack. The engine load state determination unit 23 determines the load state of the engine using these signals, and outputs an engine load state flag signal f_rack.

A method of determining the load state in the engine load state determining section 23 will be described with reference to FIG. The determination of the engine load state is performed based on the values of the rack position and the rack position change speed in the two-dimensional map of FIG. The white portion on the left or lower left of this two-dimensional map is a region where the engine load is zero, and becomes a region where the engine load is small, medium and large as the position shifts to the right or upper right. That is, in this two-dimensional map, it is determined that the engine load is higher at the upper right of the map where both the rack position and the rack position change speed take large values. Further, the rack position change speed includes a negative region. Therefore, as shown in FIGS. 3A to 3D, for example, even if the rack positions are the same, the load state is determined to be none, small, medium, or large depending on the magnitude and polarity of the rack position change speed. As a result, there is an effect that the determination of the engine load state is finely performed, and the determination as to whether the slope start assist function is completed can be made accurately. Here, the engine load state is divided into four regions (no, small, medium, and large), but the above effects can be obtained if the engine load state is three or more (no, small, and large) including no load.

Returning to FIG. 2, the signal processing circuit 24 receives an engine speed signal (rpm), and receives a signal-processed speed signal frpm and an engine speed change speed signal fgrpm. Is output. Further, the idling speed calculating circuit 25 inputs frpm and outputs an idlrpm which is an idling engine speed signal. The engine rotation state determination unit 26 determines the rotation state of the engine using these signals, and outputs a flag signal f_rpm1 indicating a change speed of the engine rotation and a flag signal f_rpm2 indicating the engine speed. Further, the signal processing circuit 27 outputs the accelerator opening signal (acc.
l), and the accelerator opening signal f after signal processing is input.
accl and fgacc which is the accelerator opening change speed signal
Output l. Here, the signal processing circuits 21, 24, 27
Performs signal processing using, for example, a low-pass filter,
The calculation of each change speed is performed using a differentiating circuit. The vehicle stop determination unit 28 receives the vehicle speed pulse signal (ve) and outputs f_stop, which is a flag signal for stopping / moving the vehicle.

The start / end judging section 29 outputs these signals (f_rack, f_rpm1, f_rpm2, facc).
1, fgaccl, f_stop), a stop flag SW status flag signal (f_break), a P brake SW status flag signal (f_park), a neutral SW status flag signal (f_nut), an ABS device status flag signal (f_abs), The ASR state flag signal (f_asr), the main SW ON / OFF state flag signal (f_main), and the like are input, and the start / end of the auxiliary function is determined using these signals, and the valve 6 is controlled according to the result. Output a signal (aus).

FIG. 4 is a diagram showing an example of a specific logical configuration of the start / end determination section 29. In the following description, f_ at the head of the input signal indicates that it is a flag signal. First, the start determination of the auxiliary function will be described. As a premise, as shown in the figure, the main circuit is turned off (f_main1) and the P brake is used (f_park) in the OR circuit 31.
1) When any signal of ABS control ON (f_abs1) is input, an output is generated in the OR circuit 31, so that the switch 32 is opened and the start of the auxiliary function is prohibited.
Otherwise, the switch 32 is closed, and the start determination is made under the following conditions.

As shown in the figure, when the foot circuit is depressed in the AND circuit 33 (f_brake1), the vehicle is stopped (f_brake1).
_Stop0) and the output of the OR circuit 34, an output is generated in the AND circuit 33. At this time, the switch 35 is closed to the start determination side, and a control signal (aus) for starting the auxiliary function is output. Here, the OR circuit 34
Is input with the gear neutral (f_nut0) and the output of the AND circuit 36. The AND circuit 36 generates an output when the engine load is not input (f_rack0) and the engine rotation state (f_rpm0) is input.

Next, the termination of the auxiliary function will be described.
The engine rotation speed f_rpm1 is flagged as large = 2 and small = 1 according to the speed of the change, and the engine speed f_rpm2 is determined, for example, according to the rotation difference with respect to the idle speed. Large = 3, Medium = 2, Small =
1 flag. As shown, the OR circuit 41
, Main switch off (f_main1), P brake use (f_park1), ASR brake control on (f_a
sr1) and the output of the AND circuit 42 are input,
An output is generated in the OR circuit 41. At this time, the switch 35 is closed to the end determination side, and the auxiliary function ends. here,
The AND circuit 42 receives the input of the gear (f_nut1) and the output of the OR circuit 43. The OR circuit 43 inputs each output of the AND circuits 51, 61, 71.

The AND circuit 51 determines conditions when the engine load is small. The AND circuit 51 has a small engine load (f_rac).
k1) and the output of the OR circuit 52 are input. Here, the outputs of the AND circuits 53, 54, and 55 are input to the OR circuit 52. The outputs of the AND circuit 56 and the OR circuit 57 are input to the AND circuit 53. AND circuit 56,
The engine speed flag is larger than 1 (f_rpm2A)
And the accelerator opening change speed is larger than a predetermined value (fgacc
Enter l1). The OR circuit 57 outputs information (f________________) whether the flag of the engine rotation change speed has changed to the larger side
rpm1A) and (f_rpm1B). The outputs of the AND circuit 58 and the OR circuit 59 are input to the AND circuit 54. The AND circuit 58 inputs that the flag of the engine rotation change speed is larger than 1 (f_rpm1C) and the accelerator opening change speed is within a predetermined value range (fgaccl2). The OR circuit 59 provides information (f_rpm2B) and (f_rpm) indicating that there is a change on the side where the engine speed flag is larger.
rpm2C). The AND circuit 55 receives an input that the vehicle is moving (f_stop1) and that the accelerator opening is less than a predetermined value (faccl1).

The AND circuit 61 determines conditions when the engine load is medium.
k2) and the output of the OR circuit 62 are input. Here, the outputs of the AND circuits 63, 64, and 65 are input to the OR circuit 62. In the AND circuit 63, there is a change to the side where the engine rotation change speed flag is large (f_rpm1D) and the accelerator opening change speed is larger than a predetermined value (fgaccl).
Enter 1). To the AND circuit 64, the accelerator opening change speed is within a predetermined value range (fgaccl2) and the output of the OR circuit 66 is input. The OR circuit 66 provides information (f_rpm) indicating that there is a change in the larger the engine speed flag.
2D) and (f_rpm2E). The AND circuit 65 receives a signal indicating that the vehicle is moving (f_stop1) and the accelerator opening is smaller than a predetermined value (a predetermined value smaller than a predetermined value of faccl1) (facc12).

The AND circuit 71 determines conditions when the engine load is large. The AND circuit 71 has a large engine load (f_rac).
k3) and the output of the OR circuit 72 are input. Here, the OR circuit 72 inputs the output of the AND circuit 73 and the state during the movement of the vehicle (f_stop1). The AND circuit 73 sets the flag of the engine rotation change speed to 2 or more (f_rpm1
E) and the engine speed flag is 2 or more (f_rpm)
2F). In addition, the OR circuit 43 receives an input indicating that the flag of the engine speed has changed to a larger value (change of flag 3 or more) (f_rpm2G). The start / end determination unit 29 determines the start / end of the auxiliary function as described above, and outputs a control signal (aus) to the valve 6 according to the result. As described above, the end determination unit is based on the condition that “there is an engine load and the engine speed is reduced or the engine speed is equal to or less than the idle speed”,
In addition, in order to perform the determination more accurately, the logical configuration is such that the determination condition is complicated when the load is small and the determination condition is simplified when the load is large.

Next, as an example, a description will be given of a determination operation when the driver blows the engine idly while the braking force is maintained by the braking device. The end of the auxiliary function must not be determined when blowing. FIG. 5 shows the state when the engine is idling.
(A) is an engine load state flag, (b) is an engine speed flag, (c) is a diagram showing an accelerator opening change speed, and (d) is a diagram showing a change in a control signal. Now with gear (f_
In the case where the driver blows the engine in the state of (nut1), the engine load state f_rack2 and the engine speed f_rpm2E become true, for example, at about 0.16 (s) shown in FIG. If the accelerator opening change speed is not considered, the AND circuit 6 in FIG.
1. An output is generated via the OR circuit 43, the AND circuit 42, and the OR circuit 41, the termination of the auxiliary function is determined, and the erroneous release of the braking force occurs. In the present invention, one of the AND circuits 64 determines whether or not the accelerator opening change speed is within a predetermined range (fg
accl2) and the engine speed (f_rpm2)
Enter E). The rate of change of the accelerator opening when blowing is
As shown by a circle in FIG. 5C, the value is outside the range of fgaccl2, and in this case, the condition of the AND circuit 64 is not satisfied, and therefore, no output is generated in the AND circuit 61. Thereby, the erroneous determination as described above can be prevented.

The present invention is not limited to the above-described embodiment. The operation of the clutch pedal is performed only at the time of starting in consideration of the slow traveling required by the driver, and the speed is automatically changed during traveling. The present invention can also be applied to a mechanical automatic transmission that automatically shifts a manual transmission by electronic pneumatic control and a slope start assist device for a vehicle equipped with a normal row type fuel injection pump.

[0027]

According to the present invention, when the accelerator pedal is depressed to start the vehicle, the engine load state obtained from the rack position information of the control rack of the fuel injection pump and the accelerator opening obtained from the accelerator opening information are obtained. Since the braking device is released using the value of the degree change speed, the vehicle can be easily and smoothly started on an uphill road, and erroneous release of the braking device can be prevented. In addition, since the braking device is released using the rack position information and the like, a clutch stroke sensor is not required, so that cost can be reduced and stable control can be always performed because there is no influence of wear of the clutch plate. . Further, a switch for fine adjustment of the clutch stroke is not required, so that a troublesome adjustment operation is not required and the cost can be reduced.

[Brief description of the drawings]

FIG. 1 is a view showing an embodiment of a slope start assist device according to the present invention.

FIG. 2 is a diagram illustrating an example of a block configuration of a control device.

FIG. 3 is a diagram for explaining a determination method in an engine load state determination unit.

FIG. 4 is a diagram illustrating an example of a specific logical configuration of a start / end determination circuit.

5 (a) is an engine load state flag, FIG. 5 (b) is an engine speed flag, and FIG.
(C) is a diagram showing an accelerator opening change speed, and (d) is a diagram showing a change in a control signal.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Air tank 2 Air chamber 3 Air passage 4 Brake pedal 4 'Brake valve 5 Stop lamp 6 Brake control valve 7 Control device 10 Slope start assist device

 ──────────────────────────────────────────────────続 き Continued on the front page F-term (reference)

Claims (3)

[Claims] 1. A braking force retaining means for retaining a pressure of a fluid for activating a braking device of a vehicle to maintain a braking force in an operating state, and a control rack position information of a fuel injection pump mounted on an engine of the vehicle. Control means for canceling the braking force maintained by the braking force holding means using the engine load state obtained from the engine rotation state and the value of the accelerator opening change speed obtained from the accelerator opening information obtained from the engine rotation information. A slope start assist device comprising: 2. The engine load state is determined to be larger toward the upper right of the map where both the control rack position and the rack position change speed take a large value on a two-dimensional map including the control rack position and the rack position change speed. The slope start assist device according to claim 1, wherein: 3. The rack position change speed includes a negative area, and the engine load state is set to three or more areas including no load from the lower left to the upper right of the two-dimensional map. The slope start assist device according to claim 2, characterized in that: