JPH10259745A - Device for reducing shock in starting vehicle - Google Patents

Abstract

PROBLEM TO BE SOLVED: To mitigate the shock of the drive system in connecting a clutch by providing a means to store the limit value of the engine speed, and controlling the engine speed so as not to exceed the limit value in a condition where a vehicle is stopped or traveling at the speed close thereto, and the clutch is turned off. SOLUTION: A transmission control unit 11 reads the limit value corresponding to a start gear of a transmission 3 from a storage means when various sensor signals and switch signals are received, the manual transmission mode is selected, the vehicle speed is below the prescribed value, and a clutch 2 is turned off, and transmits the limit value to an ECU 12. The ECU 12 judges whether or not the engine speed reaches the limit value, and when the judgment is NO, the fuel injection of the engine is controlled corresponding to the detected signal of an accelerator opening sensor 28. On the other hand, when the engine speed reaches the limit value, the fuel injection is reduced so that the engine speed does not exceed the limit value.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a vehicle starting shock reduction device.

[0002]

2. Description of the Related Art Conventionally, as an automatic transmission applied to a large vehicle such as a truck, a mechanical clutch and a gear-type transmission have been used, and a shift request based on manual operation of a driver's cab and a shift based on a running state of a vehicle have been conventionally used. There is known an electronic control system in which a clutch engagement / disengagement operation including a rotation speed of an engine and a gear shift of a transmission are electronically controlled so as to perform a shift operation to a requested position when a request is generated. Among them, there is a vehicle in which the starting state of the vehicle can be arbitrarily manually controlled depending on a driver's accelerator operation or clutch operation.

[0003]

When the vehicle starts moving, the clutch is generally slowly connected at a low speed of the engine (a predetermined speed higher than the idling speed).
Depending on the driver, there may be a case where an operation such as increasing the engine speed and quickly connecting the clutch is performed. When such a starting operation that increases the relative angular velocity before and after the clutch is performed, a shock applied to a drive system such as a fan gear, a transmission, and a propeller shaft when the clutch is connected (the torque corresponding to the angular velocity acting on the inertia moment of the engine rotation). (I.e., impact generated by so-called inertia torque), which may cause damage to the final gear of the drive system and shorten the life. The drive system strength design is made on the assumption of such severe operating conditions, but as a result, the weight and size of the unit tend to increase. In an automatic transmission equipped with a torque converter and a continuously variable transmission, the output torque of the engine, the speed ratio of the continuously variable transmission, and the engagement pressure of the lockup are reduced in order to reduce the shift shock and the lockup engagement shock at the time of starting. Controlled ones are known (JP-A-6-101512, JP-A-7-101512).
-248056).

[0004] The present invention is intended to reduce the shock of the drive system when the clutch is engaged by limiting the engine to a predetermined low-speed rotation when the driver starts the vehicle.

[0005]

According to the first aspect of the present invention, as shown in FIG. 5, means a for detecting the engaged / disengaged state of the clutch, means b for detecting the vehicle speed, and means c for detecting the engine speed.
Means for storing a limit value of the engine rotation speed, and controlling the engine rotation speed based on these output signals so as not to exceed the limit value when the vehicle is stopped or close to the running state and the clutch is in the disengaged state. And means f for performing the operations.

In the second invention, as shown in FIG. 5, means a for detecting the engaged / disengaged state of the clutch and means b for detecting the vehicle speed.
A means c for detecting the engine speed, a means d for detecting the shift stage of the transmission, a means e for storing a limit value of the engine speed corresponding to each starting gear of the transmission, and a signal e based on these output signals. Means f for controlling the engine speed so as not to exceed the limit value corresponding to the starting gear of the transmission when the vehicle is stopped or a running state close thereto and the clutch is in the disengaged state.

According to a third aspect, in the first aspect or the second aspect, as shown in FIG. 5, there is provided means g for controlling the alarm means i so as to operate while the engine speed is being limited.

[0008]

According to the first aspect of the invention, when the vehicle is stopped or in a running state close thereto, and the clutch is in the disengaged state, the engine speed is controlled so as not to exceed the limit value.
In the start operation of the vehicle, even if the accelerator pedal is depressed, the engine rotation speed is suppressed to the limit value and does not increase further. For this reason, the clutch is connected at the engine rotation speed limit value, and the inertia torque does not significantly act, so that the shock at the time of clutch connection is suppressed to a small value.

In the second invention, when the vehicle is started, the starting gear of the transmission (for example, first to third gears) is used.
When one of the speeds is selected, the engine speed is controlled so as not to exceed the limit value corresponding to the selected gear.
Therefore, the occurrence of a shock due to the connection of the clutch can be suppressed while securing the engine torque according to the load (such as the load) of the vehicle.

In the third invention, the operation of the alarm means causes
It is possible to notify the driver of the abnormal operation of the accelerator pedal and the limitation of the engine speed.

[0011]

1 is a diesel engine, 2 is a clutch, 3 is a transmission, and an output shaft of the transmission 3 is connected to a rear axle via a propeller shaft (not shown). The governor device 1A that controls the fuel injection amount of the engine fuel injection pump is provided with the clutch 2, the clutch booster 2A that performs the on / off operation is provided on the clutch 2, and the transmission 3 is provided with the gear shift unit 3A that drives the gear shift mechanism. Reference numeral 27 denotes a supply / discharge valve of the clutch booster 2A.

[0012] As a detection means necessary for vehicle shift control,
Engine rotation sensor 29 for detecting engine rotation speed
, An accelerator opening sensor 28 for detecting an amount of depression of an accelerator pedal 7 (accelerator opening), a clutch stroke sensor 22 for detecting a stroke position of the clutch 2, and a gear position sensor (a gear shift) for detecting a shift position of the transmission 3. (Built into unit 3A)
And a vehicle speed sensor 21 for detecting the rotation speed of the output shaft.
And a gear rotation sensor 23 that detects the rotation speed of the main gear that idles on the main shaft.

Manual control of clutch 2 (manual operation)
And automatic control, clutch switches 24 and 25 for detecting an initial position and an operating position of the clutch pedal are provided. A shift lever unit 4 is provided in a cab as a shift operation means of the transmission 2, and outputs a shift position instruction signal of the shift lever 4A. The knob of the shift lever 4A is provided with an automatic shift mode in which a shift is automatically changed to an optimum shift according to the running state of the vehicle (vehicle speed and accelerator opening), and a shift change in accordance with a selected shift of the shift lever 4A. A switch 5 for arbitrarily switching between the manual shift mode to be performed and the manual shift mode is provided.

The operator's cab is provided with a monitor 13 provided with a transmission position display lamp and the like, and a brake pedal switch 26 for detecting depression of a brake pedal (not shown). A buzzer 13A is provided in the cab and a lamp 13B is added to the monitor 13 as a means for warning that the engine speed is being limited.

The engine control unit 11 and the transmission control unit 12 control the speed change operation of the vehicle and the speed limit of the engine rotation based on these output signals, and serial communication (LAN) is performed between the control units 11 and 12. Are tied together. Regarding a shift operation during traveling, when a shift request based on the lever operation of the shift lever unit 4 or a shift request based on the running state of the vehicle (vehicle speed and accelerator opening) is generated, a series of shift operations is performed to shift the gear to the requested position. Control. That is, if the transmission 3 is not neutral after the clutch 2 is disconnected, the gear is removed. When the main gear rotation speed enters the synchronization region while controlling the engine rotation speed as necessary, the transmission 3 is engaged.

FIG. 2 shows a block diagram of a control system for limiting the speed of engine rotation. The engine control unit 11 includes a governor device 1A for a combustion injection pump.
The transmission control unit 11 is provided with storage means 11A for storing the engine speed limit value for each starting gear of the transmission.

In the transmission control unit 11, a detection signal of the vehicle speed sensor 21, a detection signal of the clutch stroke sensor 22, a detection signal of the gear position sensor 31, and a switch signal of the shift lever 4 (a signal for switching between an automatic transmission mode and a manual transmission mode) ), The manual shift mode is selected,
When the vehicle speed is equal to or lower than a predetermined value (stopped state or a running state close to the stopped state) and the clutch 2 is in the disengaged state, the limit value corresponding to the starting gear of the transmission 3 is read from the storage unit 11A, and the limit value is read from the engine control unit 12 Send to

Upon receiving the limit value from the transmission control unit 11, the engine control unit 12 determines whether the engine speed has reached the limit value based on the detection signal of the engine speed sensor 29. If the engine speed is below the limit,
The fuel injection amount of the engine is controlled according to the detection signal of the accelerator opening sensor 28. When the engine rotation speed reaches the control value, control (reduction correction) for reducing the fuel injection amount of the engine is performed so that the engine rotation speed does not exceed the limit value.

In the transmission control unit 11, when either the vehicle speed exceeds a predetermined value or the clutch is engaged, transmission of the limit value is stopped at that time. The engine speed limit is released, and the engine control unit 12 switches to normal engine control, and controls the fuel injection amount of the engine based on the accelerator opening and the engine speed.

While the engine speed is being limited, the engine speed does not rise even if the accelerator pedal 7 is depressed no matter how much, so the transmission control unit 11 issues a warning to the driver by the buzzer 13A and the monitor 13 The function of operating the display lamp 13B is provided.

FIG. 3 is a time chart for explaining the starting state of the vehicle. When the accelerator pedal 7 is greatly depressed after the clutch 2 is disengaged, the engine speed increases accordingly. In the conventional case, the engine speed is increased to an engine speed corresponding to the depression angle of the accelerator pedal 7 (accelerator opening). When the clutch 2 is connected, the rotation of the engine is at a high speed, so that the shock accompanying the connection of the clutch 2 is large.

In the case of the present invention, the engine speed is controlled so as not to exceed the limit value (thick line) even if the driver performs the same accelerator operation. The clutch 2 is connected at the engine rotation speed limit value, and the inertia torque does not largely act, so that the shock at the time of clutch engagement is suppressed to a small value. The starting gear of the transmission (for example, 1st to 3rd gear) is selected according to the load (load capacity, etc.) of the vehicle. Therefore, the engine speed is controlled so as not to exceed the limit value corresponding to the selected gear. By doing
While the engine torque required for starting the vehicle is secured, the occurrence of a shock due to the connection of the clutch can be reduced.

FIG. 4 is a flowchart for explaining the contents of control performed by the transmission control unit 11. In step 1, the clutch stroke sensor 2
It is determined whether the clutch 2 is in the connected state based on the detection signal of No. 2 and whether the vehicle speed is equal to or less than a predetermined value (akm / h) based on the detection signal of the vehicle speed sensor 21 in step 2.

When the determination in step 1 is no and the determination in step 2 is yes (ie, when the vehicle speed is close to stopping and the clutch 2 is in the disengaged state), the process proceeds to step 3. In steps 3 and 4, the transmission 3
Is read from the storage means 11A, and the limit value NL is transmitted to the engine control unit 12.

In step 5, based on the detection signal of the engine rotation sensor 29, the engine rotation speed NE becomes NE ≧ N.
L is determined. If the answer is yes (the engine speed is being limited), the process proceeds to steps 6 and 7 to turn on the buzzer 13A and the lamp 13B in the cab. no
In the case of (during normal control of the engine), the process proceeds to steps 9 and 10, where the buzzer 13A and the lamp 1
Turn off 3B.

If the determination in step 1 is yes,
Is no or at least one of them (that is,
If at least one of whether the clutch 2 is in the engaged state or the vehicle speed exceeds a predetermined value is satisfied), the process proceeds to step 8, and the transmission of the limit value NL is stopped (the engine control unit 12 is instructed to release the restriction on the engine speed). Command). Thereafter, in steps 9 and 10, the alarm is turned off.

The same effect can be obtained even in a vehicle having a normal transmission and clutch which does not automatically shift, provided only predetermined means are provided.

[Brief description of the drawings]

FIG. 1 is an overall configuration diagram showing an embodiment of the present invention.

FIG. 2 is a block diagram of a control system for limiting engine rotation.

FIG. 3 is a time chart for explaining a starting state.

FIG. 4 is a flowchart for explaining control contents.

FIG. 5 is a diagram corresponding to claims of the present invention.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1A Governor device of fuel injection pump 2A Clutch booster 3A Gear shift unit 11 Transmission control unit 11A Vehicle acceleration calculation means 12 Engine control unit 12A Engine control means 13A Alarm buzzer 13B Alarm lamp 21 Vehicle speed sensor 28 Accelerator opening sensor 29 Engine rotation sensor 30 Gear Position sensor

Claims (3)

[Claims] 1. A means for detecting the engaged / disengaged state of a clutch, a means for detecting a vehicle speed, a means for detecting an engine rotational speed, a means for storing a limit value of an engine rotational speed, and based on these output signals. Means for controlling the engine rotational speed so as not to exceed the limit value when the vehicle is stopped or in a running state close to it and the clutch is in a disengaged state. 2. A means for detecting an on / off state of a clutch, a means for detecting a vehicle speed, a means for detecting an engine rotational speed, a means for detecting a shift stage of a transmission,
Means for storing a limit value of the engine rotational speed corresponding to each starting gear of the transmission, and corresponding to the starting gear of the transmission when the vehicle is stopped or close to the running state and the clutch is disengaged based on these output signals. Means for controlling the engine rotational speed so as not to exceed a limit value. 3. The starting shock reduction device according to claim 1, further comprising means for controlling an alarm means so as to operate during a limitation of the engine rotation speed.