JPS623012B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an automatic transmission control device for a vehicle, and more particularly to a device that improves problems during starting.

In automatic transmission systems for vehicles, the engine cannot be started unless the transmission is in the neutral position. However, the battery voltage may drop considerably during startup.
For this reason, the stabilized power supply in the control device may drop, and the microcomputer (arithmetic circuit)
may malfunction. In such cases, the microcomputer may not issue a neutral signal, making it impossible to start the engine.

This invention was made in view of the above points,
An object of the present invention is to provide an automatic speed change control device that can reliably issue a neutral signal even if battery voltage drops during startup. According to this invention, a line directly led from the neutral switch is provided in parallel with the arithmetic circuit, so that when a signal is led to either one, it is possible to start the engine.

The present invention will be described in detail below based on an embodiment of the accompanying drawings.

FIG. 1 schematically shows an automatic transmission control device to which the present invention is applied.

In FIG. 1, an automatic transmission 1 has a lock-up device that locks a torque converter and directly drives it, and includes a torque converter 3 driven by an engine 2 and a torque converter 3 that decelerates the rotation transmitted from the torque converter 3. The transmission includes a transmission 4 that transmits information to the drive wheels, and a solenoid valve that changes the gear position of the transmission 4.
The microcomputer 6 operates based on the operation position of the gear select lever 7 by the operator, the depression angle of the accelerator pedal 9 detected by the throttle sensor 8, the rotation speed of the torque converter output shaft 11 detected by the torque converter rotation sensor 10, etc. The optimum gear position is selected by calculation, the solenoid valve 5 is driven, and the transmission 4 is switched. A voltage from a battery 12 is applied to the microcomputer 6 via a key switch 13 as a power source.

The solenoid valve 5 consists of multiple pieces,
The gear position to be engaged is determined depending on the combination of these.

An embodiment of this invention is shown in FIG. The circuit shown in FIG. 2 is incorporated into the microcomputer 6 shown in FIG.

In FIG. 2, a switch 20 is a neutral switch, which is turned on when the select lever 7 in FIG. 1 is operated to neutral (N). This neutral switch 20 has one end connected to a power source and the other end grounded, and the power source side connected to an input of an arithmetic circuit 21. Therefore, a low level signal is input to the arithmetic circuit 21 when the neutral switch 20 is turned on, and a high level signal is input when the neutral switch 20 is turned off.

In addition to the neutral switch 20, operation switches (not shown) for other gear stages are connected to the arithmetic circuit 21, and low-level and high-level signals are input thereto depending on whether they are turned on or off. When a low level signal is input to the neutral input N, the arithmetic circuit 21 determines that the select lever 7 has been operated to the neutral position (N) and outputs a low level signal to the output line ln. A diode 22 is reversely connected to this output line ln, and further connected to the base of a transistor 24 via a resistor 23. A voltage is applied between the diode 22 and the resistor 23 from a power source via a resistor 26. Further, this point is connected to the neutral input N of the arithmetic circuit 21 via a diode 25. Therefore, the neutral switch 20 is turned off, the potential of the output line ln of the arithmetic circuit 21 becomes high level, and the line ld that directly connects the neutral switch 20 to the base of the transistor 24
When the potential of the transistor 24 is at a high level, the base voltage of the transistor 24 becomes high and the transistor 24 is turned on. Further, when the neutral switch 20 is turned on and the potential of the output line ln of the arithmetic circuit 21 becomes low level, the current from the power supply flows through the resistor 26 and the diode 22.
The signal flows into the arithmetic circuit 21 via. Therefore, at this time, the base voltage of the transistor 24 becomes low and is turned off. Furthermore, even if the potential of the output line ln remains at a high level due to a malfunction of the arithmetic circuit 21 even though the neutral switch 20 is on, the resistor 23 is grounded via the diode 25 and the switch 22. , the base voltage of the transistor 24 becomes low and turns off.

The collector of transistor 24 is diode 2
7 and 28 to the base of another transistor 29. Further, a voltage from a power source is applied to the transistor 29 via a starting suppression relay 30 and a diode 31. Therefore,
When transistor 24 is turned on, transistor 2
9 is turned off, and the relay coil 30a is not excited. Further, when the transistor 24 is turned off, the transistor 29 is turned on, and the relay coil 30a is excited.

The start suppression relay 30 allows the engine to start only when the select lever 7 is in the neutral position (N). That is, when the select lever 7 is operated to a position other than the neutral position (N) and the neutral switch 20 is turned off, the output line ln of the arithmetic circuit 21 becomes high level, the transistor 24 is turned on, and the transistor 2 is turned off.
9 is turned off and the relay coil 30a is de-energized. This turns off the relay contact 30b and the engine will not start even if the key switch 13 is operated. Further, when the select lever 7 is operated to the neutral position (N) and the neutral switch 20 is turned on, the output line ln of the arithmetic circuit 21 becomes a low level, the transistor 24 is turned off, and the transistor 29 is turned on, so that the relay coil 30a is excited. This turns on the relay contact 30b, and when the key switch 13 is operated to start, the voltage of the battery 12 is applied to a starter (not shown) via the safety relay 34, and the engine is started. In addition, regardless of whether the select lever 7 is operated to the neutral position (N), the arithmetic circuit 21
Even if the output line ln is at a high level, the transistor 24 is turned off by the action of the line ld as described above, so the relay 30 is turned on and the engine is started by operating the key switch 13.

As explained above, according to the present invention, the engine can be started not only by the neutral output of the arithmetic circuit but also by the signal directly led from the neutral switch, so that the battery voltage decreases when starting. The engine can be started even if the arithmetic circuit malfunctions.

[Brief explanation of the drawing]

FIG. 1 is a block diagram schematically showing an automatic transmission control system to which the present invention is applied, and FIG. 2 is a block diagram showing an embodiment of the present invention. DESCRIPTION OF SYMBOLS 1... Automatic transmission, 6... Microcomputer, 7... Select lever, 20... Neutral switch, 21... Arithmetic circuit, 30... Start suppression relay, 13... Key switch, 34... Safety relay .

Claims (1)

[Scope of Claims] 1. A plurality of switches including a neutral switch that is turned on and off in relation to the operating position of a select bar, an arithmetic circuit that inputs signals from the plurality of switches for changing gears, and a battery control circuit. a key switch for electrically connecting to the starter; a relay disposed in series with the key switch; and a transistor that turns on the relay when it receives an on signal from the neutral switch taken out through the arithmetic circuit. An automatic transmission control device comprising: means for applying a signal from the neutral switch directly to the transistor without going through the arithmetic circuit.