JPS5878819A - Air conditioner for automobile - Google Patents

Abstract

PURPOSE:To make it needless to reset an air conditioner at the time of restarting of an engine after its stalling, by causing the air conditioner to work in a directly previous control mode when an engine switch is put again in an accessory or turn-on position within a prescribed time after the switch is put except in the accessory or turn-on position. CONSTITUTION:A relay for supplying power to a microcomputer 1 by turning on an accessory switch 10 and another relay for maintaining the power supply for a prescribed time after the turn-off of the accessory switch are included in a power supply circuit 2. When the accessory switch 10 is turned on, the microcomputer 1 performs processing in accordance with a prescribed program to carry out air conditioning in a prescribed mode. When the accessory switch 10 is temporarily turned off on account of the stalling of an engine and the engine is restarted, the maintaining relay remains on to continue the power supply to the microcomputer 1 to keep the mode in the microcomputer so that air conditioning is effected in the mode set before the stalling of the engine.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an air conditioner for an automobile, and in particular, after the engine stalls, the air conditioner is activated in the control mode immediately before the engine stalls without losing the control mode that was set immediately before the engine stalls. The present invention relates to a control device for operating a device.

Conventional automotive air conditioners can be divided into those that derive their power from an accessory power source and those that derive their power directly from the battery.In the former, after the engine stalls, the accessory power is cut off when the starter starts, and the previously set control is turned off. It has the disadvantage that the mode is lost. For example, if your engine stalls in a congested tunnel, the previously set forced air circulation mode will be canceled and you will have to quickly reset it.

Dirty outside air gets in.

On the other hand, the latter can maintain the control mode, but there is a problem that the control starts in the control mode that was set at the time of getting off the car, even though the surrounding situation has changed one hour after getting off the car. be. Unfortunately, it was raining when I got off the car and the defroster mode was on, but if the next time I get on the car is nice and warm, the hot air will blow out towards my face, making me feel uncomfortable. Also.

There is a drawback that power is constantly consumed to maintain the control mode.

SUMMARY OF THE INVENTION An object of the present invention is to provide an air conditioner in which the previously set control mode is erased when the engine is restarted after the engine stalls, and there is no need to reset the desired control mode.

Its unique feature is that even after the accessory power is turned off, power is supplied directly from the battery to the control circuit for a certain period of time to maintain the previously set control mode.

If the accessory power source is not turned on within the certain period of time, the power supply from the battery to the control circuit is also cut off.

FIG. 1 is a configuration diagram of an air conditioner that is an embodiment of the present invention. The microcomputer 1 operates on the power supplied from the power supply circuit 2, and converts the control mode set by the operating device 3 and the temperature detected by the sensor 4 into digital signals by the A/D conversion circuit 5 and inputs them. It calculates and judges internally, and drives the actuator 7 of the air conditioner via the driver 6.

The details of the power supply circuit 2 are shown in FIG. 2, the control flow of this embodiment is shown in FIG. 3, and the time interrupt flow for counting the time during which the accessory power is turned off is shown in FIG. 4.

The microcomputer 1 includes a grosssetting unit (
CPU) la, read-only memory (ROM) lb for storing program procedures, data establishment memory (RA)
M) xc, an input/output register (Ilo>ld), and a timer 1e that counts pulses obtained by dividing the system clock and generates an interrupt upon overflow.

This system includes a relay Al that supplies power to the microcomputer 1 when the accessory switch 10 is turned on.
A relay 812 is provided for supplying power for a certain period of time after the accessory switch 10 is turned off. By the way, the excitation coil that detects when the accessory switch 10 is turned on and the excitation coil that holds it after the accessory switch 10 is turned off are separated from each other when the main air conditioner, such as the compressor 20, is connected to the accessory switch 10 and uses this as a power source. This is because power is also supplied to the actuator of the device and other equipment 21 such as a radio. here.

The compressor 20 is turned on and off by an air conditioner relay 22 and a cooler relay 25 controlled by a signal from the microcomputer 1 via a resistor 23 and a transistor 24.

When the accessory switch 10 is turned on, relay All is turned on and the battery 13 is used as a power source, and the microcomputer 1
Three-terminal switching regulator 1 that supplies constant voltage to
4); Power is supplied from the power supply 13, and the microcomputer 1 starts working.

The microcomputer 1 uses a built-in power-on reset function to start a program from a vector address. Furthermore, the input and output terminals of the three-terminal switching regulator 14 include bypass capacitors 15 and 16 for stabilization.

In step 30 of the main flow shown in FIG.
812 ON signal is outputted to the transistor 18 via the base resistor 17, power is supplied directly from the battery 13 to the three-terminal switching regulator 14, and the data in the RAM/C is set to the set temperature 25tll', "AUTO". ”Set the mode to the initial state. In step 31, the control mode set by the operating device 3 is input, and in step 32, the temperature detected by the sensor 4 is converted into a digital signal by the A/D conversion circuit 5 and input.

In step 33, calculations and judgments are made based on the information input in steps 31 and 32 to determine control turns for each actuator 7 for temperature control. In step 34, control is performed according to the control pattern based on the result of step 33. Then, the loop returning to step 31 is repeated.

During the above loop, a timer 1e that divides the system clock and counts its pulses overflows, causing time interrupts at fixed time intervals.

FIG. 4 shows the processing contents of the time interrupt.

In step 40, it is determined whether the accessory switch 10 is turned on or not by setting the voltage to be input to the microcomputer 1 via the level shifter 19. When the accessory switch 10 is turned off, the time elapsed since the accessory power was turned off is calculated in step 41 by counting the number of interrupts, and in step 42, the number of interrupts is calculated to be equivalent to 3 minutes as the delay time. When this happens, the transistor 18 is turned off in step 43, the relay B12 is disconnected, and the power supply to itself is cut off.

According to the present invention, the system is capable of supplying power to the microcomputer even when the engine stalls and the starter is turned again.
The mode you set can be retained.

Moreover, when the accessory switch is turned off for more than a certain period of time,
The power supply to the microcomputer can be cut off, which has the effect of reducing power consumption.

[Brief explanation of drawings]

FIG. 1 is a configuration diagram of an air conditioner according to an embodiment. 2 shows the power supply circuit of FIG. 1, FIG. 3 shows the main flowchart of FIG. 1, and FIG. 4 shows the timer interrupt flowchart of FIG. 1.

Claims (1)

[Claims] 1. An engine switch having at least the following four contacts;
That is, a lock position that cuts off all power supply via the engine switch, an accessory position that supplies power to at least one device not directly related to the ignition system, such as a radio;
In addition to the equipment that supplies power in the accessory position, an engine switch that has an on position that supplies power to ignition system equipment and a start position that supplies power to a starter motor, etc. in addition to the equipment that supplies power in the accessory position; A vehicle that can initially set some or all of the control modes of the air conditioner to a predetermined state when the engine switch position is in the accessory position or on position, and that has a means for switching the control mode such as a switch or lever. In an air conditioner, after the engine switch position is set to a position other than the accessory or on position, the IMK is switched back to the accessory or on position for a certain period of time.
An air conditioner for an automobile, comprising means for operating in the control mode immediately before the predetermined time elapses when the air conditioner is in the on position. 2. In the configuration set forth in claim 1, means is provided for cutting off the power supply to the control device after the above-mentioned certain period of time has passed after the engine switch position is set to an accessory or other position than the on position. An air conditioner for automobiles characterized by: