JPH0520919Y2 - - Google Patents

Description

[Detailed description of the invention] [Field of industrial application] The present invention relates to an automatic transmission device that changes the engine speed of an automobile to a desired speed and transmits it to the wheels. The present invention relates to a snowy road start control device for an automatic transmission that can prevent the above.

[Conventional technology]

In general, in addition to manual transmissions, mechanical automatic transmissions called automatic transmissions have often been used as transmissions for automobiles, but with the spread of electronics, microcomputers, etc. Fully electrically controlled automatic transmissions have come into use.

This all-electrically controlled automatic transmission has 1st to 4th gear positions, and the 1st to 4th gear positions are selected by a combination of opening and closing of a pair of shift solenoid valves. By inputting vehicle speed signals, throttle opening signals, engine speed signals, shift lever position signals, etc. to the automatic transmission, the shift lever is moved to the drive range (“D”).
range), an automatic transmission control unit is provided that calculates the appropriate shift gear position corresponding to 1st to 4th speeds. The control unit then outputs a predetermined control signal for opening and closing a shift solenoid valve on the automatic transmission side, so that the automatic transmission can control the selection of an appropriate gear.

With this configuration, when driving in the drive range, the gears are shifted up sequentially from 1st gear to 2nd gear to 3rd gear to 4th gear depending on the vehicle speed, engine speed, etc.

[Problem that the invention attempts to solve]

However, when starting a car equipped with such an automatic transmission in the drive range on a slippery road such as a snowy road, there is no special shift control, so the car cannot shift up from 1st to 4th gear as normal. I will continue to do so. As a result, since the rotational speed of the wheels is small in the first speed state at the time of starting, there is a problem in that the tires are likely to spin and the vehicle starts off after a slip state and then returns to normal driving, a so-called slip start. In automobiles equipped with manual transmissions, slip start is prevented by the driver's clutch operation and shift lever operation to start in second gear, but in the case of an all-electrically controlled automatic transmission, this is not possible. Such special shift control was not possible.

The present invention was developed in view of the problems of the conventional technology, and is an automatic system that enables 2nd gear start even when the shift lever is set to the drive range when starting on a slippery road such as a snowy road. An object of the present invention is to provide a snowy road start control device for a transmission.

[Means for solving problems]

In order to solve the above-mentioned problems, the present invention provides an automatic transmission having 1st to 4th speed gear positions, a predetermined signal input to calculate the appropriate gear position, and the automatic transmission. An automatic transmission system consisting of an automatic transmission control unit that outputs control signals corresponding to 1st to 4th gears to the transmission, includes a snow switch that is attached to the vehicle and is operated when starting on a snowy road, and A slip angle calculation means calculates a slip angle from the rotational speed difference, and when the snow switch is operated and the shift lever is in the drive range, the slip angle calculated by the slip angle calculation means is a predetermined angle. The present invention is characterized by comprising a start range changing means for changing the start range by the automatic transmission control unit from first speed to second speed when it is determined that the automatic transmission control unit is above.

[Effect]

When starting on a snowy road, simply turn on the snow switch, and when the slip angle calculation means detects a slip condition, the start range changing means automatically changes the start range from 1st to 2nd speed to prevent a slip start. To prevent.

〔Example〕

Hereinafter, embodiments of the present invention will be described in detail with reference to FIGS. 1 to 3.

First, FIG. 1 is a block diagram showing the overall configuration of this embodiment. In the figure, 1 indicates an automatic transmission, the automatic transmission 1 has gear positions of 1st to 4th speed, and the engine a transmission that changes the rotation speed of the transmission to a predetermined gear ratio; a pair of shift valves that supply and discharge pressure oil from a hydraulic source to the transmission; a pair of shift valves that supply and discharge pressure oil from a hydraulic source to the transmission; It is composed of a pair of shift solenoid valves, etc., which are opened and closed in response to a control signal, and set the appropriate gear position by the combination of opening and closing. Note that the automatic transmission 1 having such a configuration
has been known for a long time.

On the other hand, 2 is an automatic transmission control unit (hereinafter referred to as
The control unit 2 (referred to as "control unit 2") includes an arithmetic processing unit consisting of, for example, a microcomputer, and a power transistor that drives a shift solenoid valve. The input side of the control unit 2 includes a vehicle speed sensor 3 that outputs a vehicle speed signal, a throttle valve switch 4 that outputs a throttle opening signal, a crank angle sensor 5 that detects the engine speed, and a braking operation by the brake device. In addition to a brake switch 6 that outputs a brake signal, an inhibitor switch 7 that detects the shift range of the shift lever, a water temperature sensor (not shown), etc., it is installed near the driver's seat and is closed when starting on a snowy road. a snow switch 8, a steering wheel angle sensor 9 that detects the steering wheel angle, a front wheel rotation sensor 10 that detects the rotation speed of the front wheels, and a rear wheel rotation sensor 1 that detects the rotation speed of the rear wheels.
The output side is connected to the automatic transmission 1.

Here, the control unit 2 stores an automatic speed change processing program (not shown), a start range change processing program shown in FIG. 2, and a slip shift processing program shown in FIG. It has a built-in program for angle calculation processing.

The control unit 2 includes a vehicle speed sensor 3, a throttle valve switch 4, a crank angle sensor 5,
Based on signals from the brake switch 6, inhibitor switch 7, etc., when the shift lever is in the drive range, the appropriate gear position corresponding to 1st to 4th gear is calculated, and a valve open signal is sent to each shift solenoid valve to close the valve. In addition to the first function (automatic shift processing function) that outputs a control signal consisting of signals, the second
The second function changes the start range from 1st to 2nd speed or returns from 2nd to 1st speed using the program shown in the figure, and the third function calculates the slip angle using the program shown in Figure 3. have.

The present embodiment is configured as described above, and its operation will be described next.

First, the first function of the control unit 2 is that when the shift lever is set to the drive range based on the signal from the inhibitor switch 7, the shift gear position corresponding to 1st to 4th gear is calculated and controlled. A signal is output to the shift solenoid valve of the automatic transmission 1 to control the transmission to an appropriate gear position.This is a conventionally known function, and its details will be omitted.

Next, the control processing operation when starting on a snowy road will be specifically described based on the programs shown in FIGS. 2 and 3.

First, the third function of the control unit 2 is executed as a subroutine by the program shown in FIG. That is, the control unit 2 reads the front wheel rotation speed from the front wheel rotation sensor 10 in step 11, reads the rear wheel revision number from the rear wheel rotation sensor 11 in step 12, and calculates the rotation speed from the difference between the front wheel rotation speed and the rear wheel rotation speed. The slip angle S is calculated (step 13).

Now, the second function of the control unit 2 is executed by the program shown in FIG. That is, when starting on a snowy road, the snow switch 8 is closed by the driver, but step 1 is not completed.
Now, the closed state of this snow switch 8 is monitored. If the determination in step 1 is ``YES'', the process moves to step 2 and monitors whether or not the shift lever is set in the drive range based on the signal from the inhibitor switch 7. If "YES" in step 2, the process moves to the next step 3, where it is determined whether the idle switch of the throttle valve switch 4 is "ON" or "OFF". When the idle switch is turned OFF, it means that the accelerator pedal is being depressed to start or accelerate the car, so move on to step 4.
In this step 4, based on the steering wheel angle signal from the steering wheel angle sensor 9, it is monitored whether the steering wheel angle is 20 degrees or less.
If the angle is more than 20 degrees, there will naturally be slippage between the left and right wheels, between the front and rear wheels, etc.
Only if the determination is "YES", proceed to step 5. Therefore, steps 1 to 4 constitute a monitoring loop for starting snowy road start control.

Next, if YES in all of steps 1 to 4, the slip angle S calculated in step 13 is read in step 5, assuming that snowy road start control is required, and in the next step 6, this slit angle is It is determined whether S is 360° or more. If the judgment is ``YES'' in step 6, it means that there is a rotation difference of 360 degrees or more between the front and rear wheels, so in this case, it is assumed that a slip start is being performed on a snowy road. In the next step 7, the start range is changed from 1st gear to 2nd gear. In this way, when the starting range is changed to 2nd speed, the vehicle, which had previously been slipping due to tire spinning, can now start smoothly and become running. If the determination in step 6 is "NO", it is assumed that the slip start has not occurred, and the process returns from step 10 to step 1.

In this way, after changing to 2nd gear start at step 7, the gears will be shifted up to 3rd and 4th gears.
In step 8, the vehicle speed signal from the vehicle speed sensor 3 is monitored, and when the vehicle speed reaches 20 km/h or more, it is assumed that normal driving has started and the start range is returned from 2nd gear to the normal 1st gear. Step 9).

In this way, in this embodiment, by simply operating the snow switch 8, when the control unit 2 detects a slip start, the start range can be changed from 1st speed to 2nd speed, thereby preventing a slip start. A reliable start is possible.

Although the embodiment has been described in which the steering wheel angle is detected in step 4, step 4 may be provided as necessary.

[Effect of idea]

The snowy road start control device for an automatic transmission according to the present invention is as described above in detail, and when starting on a snowy road, the slip angle calculating means detects slip by simply operating the snow switch in advance. Sometimes, the starting range is changed from 1st gear to 2nd gear,
Since it is configured to perform a second start, it prevents a slip start due to tire spin, and enables a smooth start even when the road surface is slippery due to fresh snow or ice.

[Brief explanation of drawings]

FIG. 1 is a block diagram showing the overall configuration of the automatic transmission according to the present embodiment, FIG. 2 is a flowchart showing the start range change processing operation, and FIG. 3 is a flowchart showing the slip angle calculation processing operation. DESCRIPTION OF SYMBOLS 1... Automatic transmission, 2... Automatic transmission control unit, 8... Snow switch, 10... Front wheel rotation sensor, 11... Rear wheel rotation sensor.

Claims (1)

[Scope of utility model registration request] An automatic transmission having a gear position of 1st to 4th gear, and a control signal corresponding to 1st to 4th gear, which calculates an appropriate gear position by inputting a predetermined signal, and sends a control signal corresponding to the 1st to 4th gear. In an automatic transmission system comprising an automatic transmission control unit that outputs a snow switch that is attached to a vehicle and is operated when starting on a snowy road, and a slip angle calculation means that calculates a slip angle from the difference in rotational speed between the front wheels and the rear wheels. When the snow switch is operated and the shift lever is in the drive range, when it is determined that the slip angle calculated by the slip angle calculation means is equal to or greater than a predetermined angle, the automatic transmission 1. A snowy road start control device for an automatic transmission, comprising a start range changing means for changing a start range by a control unit from 1st speed to 2nd speed.