JPH0796782A - Braking controller for vehicle - Google Patents

Abstract

PURPOSE:To make a degree of deceleration from the same vehicle speed fix on the same irrespective of a select range before the down shift. CONSTITUTION:A portion of retarder braking force by a retarder unit to the required braking force of vehicle speed is calculated by a shift control unit 13 on the basis of a shift type by an inhibitor switch 15 and a car speed signal of a car speed sensor 14, outputting it to a retarder driver 16, and thereby this retarder unit 7 is operated. Since a working method of a retarder in gearshifting is altered by the shift type, a braking feeling is thus improved.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a braking control device for a vehicle equipped with an automatic transmission equipped with a retarder device.

[0002]

2. Description of the Related Art Conventionally, in large vehicles, for example, automatic transmissions have been widely used to reduce driver fatigue and improve comfort during long-distance travel. Due to changes in the driving environment, the load on the brakes is increasing due to the structure of the vehicle.Therefore, in addition to engine brakes and exhaust brakes, a retarder device that exerts a predetermined auxiliary braking action is taken as a countermeasure. It is used. As an effective use of the retarder device, for example, Japanese Utility Model Laid-Open No. 63-16437.
Japanese Patent No. 6 discloses an arrangement in which the braking force of the retarder is adjusted according to the gear position of the transmission and whether or not the exhaust brake is used.

[0003]

However, when the driver needs engine braking to change the select position and downshifts, the engine braking force during shifting varies depending on the amount of increase in engine rotation during that time. That is, even if the vehicle speeds are the same, for example, when selecting from 2nd range from 4th speed and
Although the engine braking force is different when the range is selected, the conventional vehicle braking control device operates in a uniform manner when the retarder is actuated. There was a problem that the degree of deceleration was different and the braking feeling was bad. Therefore, in view of such conventional problems, the present invention provides a vehicle braking control device capable of obtaining a stable braking feeling irrespective of the gear position before shifting when decelerating from the same vehicle speed. The purpose is to do.

[0004]

For this reason, the present invention provides a braking control device for a vehicle equipped with a retarder device and an automatic transmission for performing shift control according to an engine load and a preset shift rule. Controlling the retarding force of the retarder based on the shift type detecting means for detecting the shift type of the automatic transmission and the shift type detected by the shift type detecting means when the automatic transmission is downshifted And a control means.

[0005]

When the driver operates the select lever of the automatic transmission to downshift to decelerate the vehicle, the shift type detection means shifts from the 4th speed of the D range to the 2nd range or the same D speed.
Also in the range, whether the shift is from the third speed to the second range, or the type of shift is detected. Since the control means controls the retarding force of the retarder based on the type of gear shift, the retarder works differently, and even if the size of the engine brake varies depending on the type of gear shift, when decelerating from the same vehicle speed, the total The braking force can be set to the same level regardless of the type of shift.

[0006]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described below with reference to the drawings. FIG. 1 is a configuration diagram showing an embodiment of the present invention. The automatic transmission 3 is connected to the engine 1 via the torque converter 2, and the output of the automatic transmission 3 is transmitted to the differential gear 6 of the drive wheel 5 by the propeller shaft 4. Further, a fluid type retarder device 7 is attached to the propeller shaft 4 and is operated by a retarder drive device 16.

In the retarder device 7, a pump is used to pressurize the liquid, and the proportional solenoid valve is used to throttle the flow passage when necessary, so that the generated resistance produces a braking force. Here, normally, the retarder drive device 16 is operated in a state in which a retarder switch (not shown) is “ON”, for example, in conjunction with a brake operation of a driver or in a predetermined operating state in which the automatic transmission 3 operates in the deceleration direction. It is driven by and operates so as to supplementally apply a braking force.

The hydraulic control device 12 is connected to the select lever 8 and realizes a required shift speed based on the selected position and a control command from the shift control unit 13. In addition, the hydraulic control device 12 is provided with an inhibitor switch 15 that operates corresponding to the position of the select lever 8. The shift control unit 13 sends a control command for shifting to the hydraulic control device 12 as described above, and further, in the present embodiment, the change of the select position by the vehicle speed signal from the vehicle speed sensor 14 and the inhibitor switch 15. Based on the situation, the vehicle speed and the type of shift are determined, the required engine brake auxiliary braking amount by the retarder device 7 is obtained, and a retarder control command is sent to the retarder drive device 16. Retarder drive 16
Then, in addition to the above-described auxiliary braking action that is activated by turning on the ordinary retarder switch, the retarder device 7 is driven when the retarder control command is received.

FIG. 2 shows the flow of retarder control in the shift control unit 13. First, in step 101, the output of the inhibitor switch 15 is read.
Then, in step 102, it is determined whether or not downshift is requested. Here, when the select lever 8 is shifted to the 2 range or the 1 range or the overdrive cancel switch is operated, it is determined that the downshift is requested.

When the downshift is requested, the routine proceeds to the next step 103, where the target gear ratio Gp1 after the downshift is obtained based on the shift range signal from the inhibitor switch 15, and the routine proceeds to step 104. Step 104
Then, the vehicle speed V immediately before the downshift is read from the vehicle speed sensor 14, and the gear ratio Gp0 immediately before the downshift is calculated. As a result, the change before and after the shift, that is, the change in the gear ratio, and hence the type of shift is obtained. Step 1
01 to 104 constitute the shift type detecting means of the invention.

Then, in step 105, the retarder braking force (T) is calculated based on the vehicle speed V and the gear ratio Gp0 immediately before the downshift and the downshift target gear ratio Gp1.
3 and 4 show the difference in the braking force required by the retarder device depending on the type of shift. Even if the required braking force (To) at the same vehicle speed is the same, when shifting from the state of the 4th speed of FIG. 3 to the 2 range and when selecting from the state of the 3rd speed of FIG. Since the amount of increase in engine rotation is different, the engine braking force (TB) is different, and thus the required braking force (T) by the retarder device is different.

Thereafter, in step 106, the amount of current (I) corresponding to the retarder braking force (T) calculated in step 105 is calculated. In step 107, this current amount is output to the proportional solenoid valve to operate the retarder device 7, and the required retarder braking force (T) is exerted. Then, the control operation described above is repeated thereafter. Step 1 above
05-107 constitutes the control means of the invention. In addition,
When the downshift is not requested in the determination in step 102, the process exits from this subroutine and another process is performed.

Since the present embodiment is configured as described above and changes the way the retarder works during gear shifting depending on the type of gear shifting, the conventional feeling of retarder having the same effectiveness is eliminated and comfort is improved. You can drive Note that the retarder braking force (T) is calculated in advance by inputting the required retarder braking force (T) in the form of a map for each vehicle speed and each type of shift, and then calculating the required retarder braking force (T). It may be read. Further, the required braking force (To) for each vehicle speed is obtained from a map, and the change in engine rotation at the corresponding shift is calculated to calculate the engine braking force (T
B) may be calculated, and the retarder braking force (T) may be calculated each time by T = TO-TB. Further, although a fluid type retarder device is used in the embodiment, the present invention is not limited to this, and other types of retarder devices such as an electromagnetic type can also be used.

[0014]

As described above, according to the present invention, the braking force of the retarder is controlled based on the type of gear shift.
Even if the retarder works differently and the size of the engine brake varies depending on the type of shift, when decelerating from the same vehicle speed, the same stable braking force is obtained regardless of the type of shift, and the braking feeling is improved. Can be improved.

[Brief description of drawings]

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

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

FIG. 3 is a diagram for explaining braking force sharing by a retarder when downshifting from 4th speed to 2nd range.

FIG. 4 is a diagram for explaining braking force sharing by a retarder when downshifting from 3rd speed to 2nd range.

[Explanation of symbols]

 1 Engine 2 Torque Converter 3 Automatic Transmission 4 Propeller Shaft 5 Drive Vehicle 6 Differential Gear 7 Retarder Device 8 Select Lever 11 Shift Mechanism 12 Hydraulic Control Device 13 Shift Control Unit 14 Vehicle Speed Sensor 15 Inhibitor Switch 16 Retarder Drive Device

Claims (2)

[Claims] 1. A braking control device in a vehicle equipped with a retarder device and equipped with an automatic transmission for performing shift control according to an engine load and a preset shift rule, wherein the type of shift of the automatic transmission is changed. And a control unit that controls the braking force of the retarder based on the type of shift detected by the shift type detection unit when the automatic transmission is downshifted. A braking control device for a vehicle. 2. The braking control device for a vehicle according to claim 1, wherein the control means reduces the braking force of the retarder as the change of the gear ratio in the gear shift increases.