JPH0725322A - Retarder control device for vehicle - Google Patents

Abstract

PURPOSE:To control braking force in advance so as not to generate a slip due to the excessive braking force of a retarder even during snow road travel. CONSTITUTION:A mode signal indicating the selected state of a speed change mode changeover switch 15 added to a select lever 8 is inputted to a retarder control device 16 from a speed change control unit 13, and a retarder switch 17 is connected to the retarder control device 16. When the retarder switch 17 is on and the speed change mode changeover switch 15 is in a 'snow' mode, the retarder control device 16 operates a retarder device so as to output braking force lower than that in the normal mode. The generation of a wheel slip is thereby prevented so as to enable driving with a sense of security and composure.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a control device for a retarder device which is connected to a drive system of a vehicle equipped with an automatic transmission to apply a braking action.

[0002]

2. Description of the Related Art Conventionally, for example, in a large-sized vehicle, an automatic transmission is widely used to reduce driver fatigue and improve comfort in long-distance driving. As the environment changes,
Since the load on the brake is also large in terms of vehicle structure, a retarder device that exerts a predetermined auxiliary braking action is used in addition to the engine brake, the exhaust brake, and the like, as a countermeasure against this. As an operation mode for effectively operating such a retarder device in accordance with the operating state of the vehicle, for example, Japanese Patent Laid-Open No. 4942018 has a wheel rotation speed sensor, and the wheel rotation speed or the wheel rotation speed is provided. It is disclosed that the braking force of the retarder device is variably controlled based on the comparison between the slip ratio and the reference value.

Further, Japanese Patent Laid-Open No. 3-273966 discloses a retarder device which is controlled based on a preset map using the wheel slip ratio and steering steering angle as parameters. In this device, in addition to the retarder switch, signals from a vehicle speed sensor, a wheel speed sensor for detecting a driving wheel speed, a wheel steering angle sensor, and a brake switch are input to the control unit. Then, the control unit reduces the braking force by the retarder as the slip ratio increases when the slip ratio of the wheels is less than a certain value, and when the slip ratio exceeds a certain value and is within a predetermined range, it becomes a certain value. A control map is set so that when the slip ratio exceeds a predetermined range, it is maintained, and the slip ratio again decreases as the slip ratio increases, and the slip ratio relatively decreases as the wheel steering angle increases.

The control unit calculates the slip ratio from the vehicle speed and the driving wheel speed, selects the control characteristic corresponding to the steering angle from the control map, and outputs the retarder actuation signal based on the slip ratio and the control characteristic. It is like this. Thus, for example, when cornering or braking on a slippery road surface, it is intended to prevent the retarder from exerting too much braking force.

[0005]

However, in these conventional retarder control devices, even if the braking force due to the operation of the retarder is variably controlled, a signal for determining the appropriate braking force is provided. Can only be obtained after a slip condition has actually occurred, for example the slip ratio of the wheel. Therefore, the operation of the retarder device is always a posterior control, and even when it is expected that slip will occur more easily than in other cases, for example, when running on a snowy road, it will occur before the slip condition actually occurs. It was impossible to prevent. Therefore, an object of the present invention is to provide a vehicular retarder control device in which the braking force is appropriately controlled in advance in accordance with the traveling mode of the vehicle, focusing on the above conventional problems.

[0006]

Therefore, the present invention is a retarder control device for an automatic transmission-equipped vehicle equipped with a retarder device, the mode detecting device detecting a running mode of the vehicle, and the mode detecting device detecting the mode. And a control means for operating the retarder device by selecting from a plurality of preset control characteristics corresponding to the travel mode set.

[0007]

[Operation] The traveling mode is detected by the mode detecting means,
The control means actuates the retarder device according to a control characteristic selected from a plurality of modes in accordance with the traveling mode. Thus, for example, when the vehicle is in the snowy road mode, by operating the retarder device with a characteristic of outputting a braking force lower than usual, it is possible to prevent wheel slippage due to excessive braking force.

[0008]

1 is a block diagram showing an embodiment of the present invention. An automatic transmission 3 is connected to an engine 1 via a torque converter 2, and an output of the automatic transmission 3 is transmitted to a differential gear 6 of a drive axle 5 by a propeller shaft 4. Further, between the automatic transmission 3 and the propeller shaft 4, a fluid type retarder device 7 connected to the automatic transmission is attached, and the retarder control device 16 is provided.
It is designed to be activated by. Retarder device 7
Is designed to generate a braking force by the generated resistance by pressurizing the fluid with a pump and narrowing the flow path when necessary. Here, in a state where a retarder switch (not shown) is normally “ON”, For example, it is driven by the retarder control device 16 in synchronism with the brake operation of the driver and operates so as to supplementally apply a braking force.

The automatic transmission 3 comprises a hydraulic control device 12 and a shift control unit 13 for driving the shift mechanism portion 11. The shift control unit 13 includes a microcomputer, and sends a control command to the hydraulic control device 12 based on an engine load such as a throttle opening and a vehicle speed signal from a vehicle speed sensor (not shown). The hydraulic control device 12 is connected to the select lever 8 and realizes a required shift speed based on the selected position and the control command from the shift control unit 13.

The shift control unit 13 also includes a shift mode changeover switch 15 attached to the select lever 8.
Are connected. The speed change mode switch 15 can be switched between a "normal" mode and a "SNOW" (snowy road running) mode, and the "SNOW" mode is selected when running on a snowy road where the road surface has a low friction coefficient and slips easily. By doing so, the shift characteristics of the automatic transmission in the shift control unit 13 are switched to those suitable for the snowy road.

A retarder switch 17 is connected to the retarder control device 16, and the retarder switch 17 is connected to the retarder switch 17.
Is ON, for example, the retarder device is operated so as to supplementally apply the braking force in conjunction with the driver's brake operation or in a predetermined operating state in which the automatic transmission operates in the deceleration direction. Let Here, a plurality of control characteristics are set in the retarder control device 16. A mode signal is supplied from the shift control unit 13 to the retarder control device 16 in accordance with the shift mode selected by the shift mode changeover switch 15. Then, the retarder control device 16 operates the retarder device according to the control characteristic selected from the plurality of control characteristics corresponding to the mode signal.

FIG. 2 shows the flow of retarder control in the retarder control device 16. First, in step 101, the output of the retarder switch 17 is read and it is checked whether or not the retarder switch 17 is "ON". If the retarder switch 17 is "ON", the process proceeds to the next step 102, the mode signal indicating the state of the shift mode changeover switch 15 is read from the shift control unit 13, and whether the "SNOW" mode is set or not. It is checked whether it is in the mode.

When it is determined that the "normal" mode is selected, at step 103,
An operation command is output to the retarder device 7 with the first characteristic of outputting a normal braking force. On the other hand, in step 102, "SN
When it is determined that the "OW" mode is selected,
Proceeding to step 104, the operation command based on the second characteristic that outputs the braking force set lower than in the “normal” mode is output to the retarder device 7. When the retarder switch 17 is not “ON” in the check in step 101, the retarder device 7 is not operated and this flow ends. Here, the shift mode changeover switch 1
5 and the shift control unit 13 constitute the mode detecting means of the invention, and the retarder control device 16 constitutes the controlling means.

This embodiment is constructed as described above, and the shift mode changeover switch 15 which is selectively operated according to the traveling mode is attached to the select lever, and the snow road is a low friction coefficient road which is apt to cause a slip state. "SNO
When the "W" mode is selected, the retarder device is operated so as to output a braking force lower than that in the "normal" mode, so that the occurrence of wheel slip due to excessive braking force is prevented, and there is a sense of security and a margin. You can drive.

As the traveling modes, the "SNOW" and "normal" modes corresponding to the snowy road by the shift mode changeover switch 15 of the automatic transmission are shown as an example, but not limited to this, other "rainy weather" and "normal" modes. It is possible to set various driving environments such as weather and road conditions such as "uphill road" and "downhill road", and it is also possible to correspond to driving modes such as "high speed running", and braking force characteristics suitable for each By setting, the retarder device is pre-controlled and a comfortable and affordable driving environment is obtained. Further, in the embodiment, the shift mode changeover switch attached to the select lever 8 is used to detect the traveling mode, but the installation site is not limited to this, and it can be provided at an appropriate site such as an instrument panel. . Further, although the retarder device 7 is of a fluid type in this embodiment, an electromagnet type or permanent magnet type retarder device can also be used, and a multi-plate clutch type retarder device using a friction plate can also be used. Can be applied. In addition, in the embodiment, the braking force is applied when the retarder device is linked to the normal brake operation or when the automatic transmission operates in the deceleration direction in a predetermined operating state. The driving mode may be one in which the braking action works by turning the retarder switch "ON" without operating the foot brake, and these can be selected.

[0016]

As described above, the present invention selects from a plurality of preset control characteristics corresponding to the mode detecting means for detecting the running mode of the vehicle and the running mode detected by the mode detecting means. Then, the retarder device is operated, so that the braking force by the retarder device is applied with the optimum characteristics for the traveling mode of the vehicle. In particular, the output of the shift mode changeover switch of the automatic transmission is used to detect the mode of normal road running and low friction coefficient road running, and the braking force characteristic is lower than that of normal road running for low friction coefficient road running. When the retarder device is operated with the control characteristic set to be low, the occurrence of wheel slip due to excessive braking force is prevented in advance, and there is an effect that the vehicle can be operated with peace of mind.

[Brief description of drawings]

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

FIG. 2 is a flowchart showing a control flow in the embodiment.

[Explanation of symbols]

 1 Engine 2 Torque Converter 3 Automatic Transmission 4 Propeller Shaft 5 Drive Axle 6 Differential Gear 7 Retarder Device 8 Select Lever 11 Shift Mechanism Section 12 Hydraulic Control Unit 13 Shift Control Unit 15 Shift Mode Change Switch 16 Retarder Control Unit 17 Retarder Switch

Claims (2)

[Claims] 1. A retarder control device for a vehicle equipped with an automatic transmission including a retarder device, comprising: a mode detection means for detecting a travel mode of the vehicle; and a travel mode detected by the mode detection means in advance. A retarder control device for a vehicle, comprising: a control means that operates the retarder device by selecting from a plurality of set control characteristics. 2. The mode detecting means discriminates between normal road traveling and low friction coefficient road traveling based on the output of a shift mode changeover switch of the automatic transmission, and the control means carries out low friction coefficient road traveling. On the other hand, the retarder control device for a vehicle according to claim 1, wherein the retarder device is operated according to a control characteristic in which a braking force characteristic is set to be lower than that of traveling on a normal road.