JP2830381B2 - Control device for automatic transmission - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to a control device for an automatic transmission, and more particularly, to a control for a power supply type throttle sensor in a control device for an automatic transmission.

[Prior Art] In an automatic transmission for a vehicle, a so-called power supply type throttle sensor of a type in which a necessary power is supplied from a power supply device to detect an opening degree of a throttle is used. FIG. 4 shows an example of a configuration of a control device of an automatic transmission having a general power supply type throttle sensor.

A throttle sensor 2 in the figure DC power is inputted through the power line a from the throttle sensor power supply 44, it encodes the opening of the throttle valve, and outputs this to a signal line b ₁ ~b ₄ as a digital signal. This output signal is input via a buffer 45 to a microcomputer MPU 40 which forms a part of the control unit ECU 4 which is a main part of the control device.

When the failure of the power supply line a is detected by the failure detection circuit 42 which constantly detects the presence or absence of a short circuit or grounding in the power supply line a of the throttle sensor power supply device 44 and, in some cases, the presence or absence of a disconnection failure (hereinafter simply referred to as failure), The failure detection circuit 42 outputs a signal indicating that a failure has occurred to the microcomputer MPU 40.
At the same time, the subsequent failure detection is stopped, and the throttle sensor switch circuit 43 is controlled so that the output power of the power supply device 44 is cut off.

When the microcomputer MPU 40 receives the signal indicating that there is a failure, the microcomputer MPU 40 stores the signal and outputs this signal to 0 regardless of the output signal of the throttle sensor 2 at that time.
That is, the throttle opening is regarded as zero, and so-called fail-safe control is performed in the selection of the shift speed in the automatic transmission thereafter. In this case, the microcomputer
Based on the output signal value of the vehicle speed sensor 3 and the throttle opening which is regarded as zero, the MPU 40 performs shift switching according to a shift diagram shown in FIG. 3 as a general shift diagram.

For example, if the vehicle is accelerating at the second speed at point P on the shift diagram before the occurrence of the failure, the throttle opening is regarded as zero at the same time as the occurrence of the failure. , And thus the shift speed shifts from the second speed to the third speed. As described above, in the fail-safe control, the gear stage achieves its purpose by shifting to the upshifting direction. The fail-safe control prevents sudden deceleration resulting from shifting to the point R and shifting down. ,
Danger will be avoided.

In the fail-safe control, the shift position is selected by assuming the throttle opening to be zero, so that the upper shift position is always selected, which reflects the driver's intention to accelerate which is originally required as an automatic transmission. Since the shift stage is not established, the driver can notice the occurrence of the failure.

However, if the starting and acceleration are not repeated in the operation of the vehicle, the failure is often not perceived by the driver. In such a case, if the operation of the vehicle is terminated and the ignition switch is turned off without the driver noticing the failure, the failure detection circuit will be renewed the next time the ignition switch is turned on, as in the previous start. , The failure detection on the power line a of the throttle sensor is performed again.

If the failure has already ended for some reason and the power line a of the throttle sensor has returned to a normal state, the shift control is performed based on the normal output signal of the throttle sensor, while the speed control is performed again. When a failure is detected, the failure detection circuit stops the subsequent failure detection, and the microcomputer MPU 40 selects the shift position by regarding the throttle opening as zero in the same manner as described above in accordance with the principle of fail-safe control. For this reason, the vehicle can only start slowly, irrespective of the driver's intention to accelerate, and for the first time, the driver notices an abnormality in the transmission.

[Problems to be Solved by the Invention] When fail-safe control is performed at the time of power failure of the throttle sensor, if the throttle opening is regarded as zero and operation is continued regardless of the output signal of the throttle sensor, the driver Is not accurately transmitted to the automatic transmission, and acceleration is not performed quickly. The driver can detect this fault condition of the automatic transmission when accelerating from the normal stop state or the slow-moving state, but even after detecting this, the automatic transmission itself continues the fail-safe control and the vehicle operates normally. Operation is difficult, especially in the case of restart after stopping once. Thus, there is a demand that the operation be continued within a range that does not hinder the operation in the event of a minor failure. However, the conventional operation of the control device of the transmission has been difficult as described above.

SUMMARY OF THE INVENTION It is an object of the present invention to provide a control device for an automatic transmission having a power supply type throttle sensor, in which after a failure such as a short circuit occurs in a power supply circuit of the throttle sensor, operation is performed as much as possible within a range that does not interfere with the failure state. It is an object of the present invention to provide a control device for an automatic transmission in which a shift operation of a transmission that reflects a driver's intention to accelerate is performed.

Means for Solving the Problems It is an object of the present invention to provide a power supply device capable of supplying output power, a throttle sensor supplied with the output power and outputting a throttle opening signal of a vehicle, and a speed signal of the vehicle. A failure sensor in the circuit of the output power supply for detecting a failure and outputting a signal indicating that there is a failure when a failure occurs in the circuit; output signals of the throttle sensor, the vehicle speed sensor, and the failure detection unit And a control unit for outputting a disconnection signal for turning off the output power and a detection stop signal for stopping the fault detection when the fault signal is generated. Sometimes, in a control device for an automatic transmission of a type that performs fail-safe control by treating the throttle opening as zero in the selection of a shift stage, the control unit is configured to reduce the speed signal to zero after a failure signal is generated. And outputting a restart signal for failure detection to the failure detection unit when the automatic transmission controller detects that

 The present invention is based on the following findings.

In general, plug connection is used in vehicle wiring, but not only in the case of a vehicle, but also in the case of plug connection. As a result, an instantaneous short-circuit or a failure such as grounding tends to occur. It is often experienced that such a momentary failure has already returned at the next moment. The inventor of the present invention has proposed that, in a control device for an automatic transmission in which such a momentary failure as described above is likely to occur due to vibration of a vehicle, etc.
The focus is on performing this most before the driver restarts, which requires the most acceleration, when the vehicle is stopped, and aims at achieving the goal.

In view of the above, in the present invention, the presence or absence of a failure is detected again when the vehicle stops after the presence of a failure is detected, and if the failure state has already been completed and returned to normal, the throttle power is turned on as it is. The automatic transmission is operated in a normal state to obtain a comfortable feeling of acceleration in subsequent driving.

[Operation] If a vehicle stops for any reason after a failure occurs, the control unit EC detects this vehicle stop based on a signal from the vehicle speed sensor.
U again sends a detection restart signal to the failure detection circuit to detect the presence or absence of the failure, and the failure detection circuit detects whether the failure of the power line of the throttle sensor continues. The control unit performs predetermined shift control depending on whether or not the failure continues.

[Example] A control device for an automatic transmission according to the present invention will be further described with reference to the drawings.

FIG. 1 is a block diagram of a control device for an automatic transmission according to one embodiment of the present invention, and FIG. 2 is a flowchart showing a recovery control procedure for a power supply line failure of a throttle sensor in the control device of this embodiment. FIG.

In FIG. 1, the control device for this automatic transmission comprises an ignition switch for starting the vehicle, a throttle sensor 2, a vehicle speed sensor 3, a control unit ECU 4, transmission solenoids 5 to 7, and an alarm circuit (ANN) 8. Control unit ECU4
Inside, a microcomputer MPU 40 for controlling the entire transmission according to a predetermined program, a constant voltage source 41, a failure detection circuit 42, a throttle sensor switch circuit 43, a throttle sensor power supply device 44, and input / output buffers 45 to 50 are provided. included. The ignition switch 1 keeps the battery B and the constant voltage source 41 together with the closing operation, and connects the battery B to the failure detection circuit 42. Upon receiving the power supply from the constant voltage source 41, the microcomputer MPU 40 starts its operation, and at the same time, controls the failure detection circuit 42 to turn on the output of the throttle sensor power supply device 44 to the throttle sensor switch circuit 43.

The throttle sensor 2 is a bit type sensor, which codes the opening of the throttle valve and outputs it as a digital signal, which is input to the microcomputer MPU 40 via the buffer 45. That is, the throttle sensor 2
It is supplied with a DC power source of a predetermined voltage from the throttle sensor power supply 44, and outputs a digital signal of 1 or 0 four line b ₁ ~b ₄ of each signal.

The throttle sensor power supply device 44 is turned on and off by a switch circuit 43 controlled by the microcomputer MPU 40, so that its output power can be supplied to the throttle sensor 2 via the throttle sensor power supply line a accordingly. The failure detection circuit 42 is controlled by the microcomputer MPU 40 to detect whether there is a failure such as a short circuit or grounding of the throttle sensor power line a of the throttle sensor 2.

Each of the solenoids 5, 6, 7 is controlled by the microcomputer MPU 40 so as to be in an excited state or a non-excited state. According to a combination of the excitation and the non-excitation of these solenoids, the automatic transmission performs predetermined operations via its hydraulic circuit. Is selected.

As shown in FIG. 2, in the control device of the automatic transmission according to this embodiment, when the ignition switch 1 is turned on, the failure detection circuit 42 detects the failure in the output power line a of the throttle sensor power supply device 44. It is monitored whether or not a fault has occurred (step S ₁ ). If a fault is detected in the throttle sensor power supply line a, the fault detecting circuit 42 outputs a fault to the microcomputer MPU 40, and the microcomputer MPU 40 thereafter detects the fault. At the same time, a command signal for turning off the throttle sensor power supply device 44 is output to the switch circuit 43 (step S ₂ ), whereby the power supply to the throttle sensor 2 is stopped, and the output signal is output to the throttle fully open state. Output as a signal. However, like the control in the conventional transmission, the microcomputer MPU4
By 0, this throttle opening is regarded as zero, and fail-safe control is performed. Microcomputer MPU40 has subsequently monitors the signal of the vehicle speed sensor 3 vehicle detecting whether the stop (Step S _3).

Step microcomputer MPU40 again the stop state of the vehicle is detected in S ₃ and outputs a detection instruction signal of the presence or absence of the failure to failure detection circuit 42 (step S _4).
Upon receiving a signal indicating no failure from the failure detection circuit 42, the microcomputer MPU 40 causes the throttle sensor switch circuit 43
Issues a power-on command signal of the throttle sensor power supply 44 (step S _5), it is thereby power again to the throttle sensor 2 is supplied to, based on the output signal of the throttle sensor 2 in the control system for an automatic transmission Normal shift control is performed.

If the failure has not recovered, the failure detection circuit 42 outputs a signal indicating that there is a failure as in the previous case, so that the fail-safe control is continued based on the control signal of the microcomputer MPU40. In this case, the microcomputer MPU 40 outputs the abnormality of the throttle sensor to the alarm circuit (ANN) 8 for the first time, and the driver knows the failure for the first time. If the vehicle continues to operate as it is, the failure detection is performed many times when the vehicle stops, and if the failure of the throttle power supply line a has been completed and the vehicle has returned to normal, the automatic transmission operates normally. Will be performed. In this case, since the automatic transmission has selected the lowest gear according to the stop state, the normal shift operation can be restored without giving the driver any sense of abnormality and without danger.

The fail-safe control in the magnetic head control device of the present embodiment is the same as the fail-safe control described in the related art. That is, if the vehicle is accelerating at the second speed at the point P on the conversion diagram before the occurrence of the failure in FIG. 3, the failure of the throttle sensor is detected and the point P on the shift diagram is detected. From the second gear to the third gear. The fail-safe control prevents sudden deceleration resulting from shifting to the point R and downshifting to the first speed.

In the present embodiment, the case where the signal of the throttle sensor is of a digital type called a bit system has been described. However, the present invention is not limited to this case. The present invention can be applied to a transmission control device.

[Effects of the Invention] In the control of the control device for the automatic transmission according to the present invention, if a failure occurs in the throttle sensor power supply circuit, then if the vehicle speed is detected to be zero, the presence or absence of the failure is detected again. With this configuration, if the malfunction of the throttle sensor power supply circuit has already been recovered, normal gear shifting control can be performed again when the vehicle restarts, and the failure is detected only after the ignition switch is turned on again. Compared to the conventional automatic transmission control device that did not perform the above, the opportunity to shift to normal operation when the vehicle needs to be most accelerated, starting from a stopped state, was obtained. It is possible to provide an automatic transmission control device that can reflect the driver's intention to accelerate without danger.

[Brief description of the drawings]

FIG. 1 is a block diagram of a control device for an automatic transmission according to one embodiment of the present invention, FIG. 2 is a flowchart showing a recovery procedure from a short-circuit failure in the control device of the embodiment of FIG. 1, and FIG. FIG. 4 is a shift diagram for explaining a shift operation in the present invention and a conventional automatic transmission control device. FIG. 4 is a block diagram of a conventional automatic transmission control device. (Explanation of reference numerals) 1 ... Ignition switch 2 ... Throttle sensor 3 ... Vehicle speed sensor 5-7 ... Shift solenoid 42 ... Fault detection circuit 43 ... Switch circuit 44 ... Throttle sensor power supply ECU4 ... Control part MPU40 ...... microcomputer a ...... throttle sensor power supply line b ₁ ~b ₄ ...... throttle sensor signal line

──────────────────────────────────────────────────続 き Continued on the front page (58) Field surveyed (Int. Cl. ⁶ , DB name) F16H 59/00-61/12 F16H 61/16-61/24 F16H 63/40-63/48

Claims (1)

(57) [Claims] A power supply device capable of supplying an output power; a throttle sensor supplied with the output power to output a throttle opening signal of a vehicle; a vehicle speed sensor detecting a speed signal of the vehicle; A failure detection unit that detects a failure in the circuit of the above and outputs a signal indicating the presence of a failure when a failure occurs in the circuit; and an output signal of the throttle sensor, the vehicle speed sensor, and the failure detection unit, and receives the failure signal. And a control unit for outputting a disconnection signal for turning off the output power and a detection stop signal for stopping the failure detection. A control device for an automatic transmission of a type that performs fail-safe control by treating the speed signal as zero, wherein when the control unit detects that the speed signal is zero after the generation of a signal indicating a failure, the failure detection unit Control apparatus for an automatic transmission, characterized in that, for outputting a restart signal of the fault detection for.