JPS63270221A - Control system for air conditioner for vehicle - Google Patents

Abstract

PURPOSE:To suppress the sharp reduction of the engine revolution speed and engine stall by ON/OFF-controlling an air conditioner according to the engine revolution speed determined according to the load of the air conditioner. CONSTITUTION:In an air conditioner control circuit 20, the engine revolution speed characteristic (hysteresis) is constituted on the basis of each engine revolution speed r1, r2 selected according to the coolant pressure by a pressure sensor 12 of a compressor 10 for air conditioning, and the engine revolution speed r1, r2 determined by a judging circuit 18 and the signal input from an engine revolution speed sensor 14 are compared. When the engine revolution speed detected by the sensor 14 is larger than a set revolution speed r1, an air conditioner starts operation. When the engine revolution speed becomes less than the set revolution speed r2, the operation of the air conditioner is suspended. In this case, if the pressure of the air compressor 10 is high, and the load of the air conditioner which is applied onto the engine is large, the revolution speed of the engine for controlling the ON/OFF of the air conditioner is set high, and the smooth idling can be secured.

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention is directed to a vehicle air conditioner control system, particularly in the air conditioner control of a vehicle equipped with an automatic transmission (A/T), to reduce the air conditioner load on the engine. related to control systems.

[Related technology] As a related technology to the present invention, Utility Model Application Publication No. 50-12715
No. 1, Utility Model No. 51-95152, Utility Model No. 59-873
No. 12, Utility Model No. 59-87313, Utility Model No. 52-115
A technique described in Publication No. 044 has been proposed.

[Conventional technology] An electronic control device (
Idle speed control (ISO) is generally performed, which is stored in the ECU), detects the engine condition using a detection signal from a sensor, and controls the engine speed to a target speed.This improves fuel efficiency and eliminates maintenance. Effects such as this can be obtained.

However, conventionally, air conditioner control circuit (hereinafter referred to as "air conditioner")
In an A/T vehicle equipped with an A/T system, the air conditioner is controlled by the engine speed, as shown in Figure 6, when the air conditioner is turned on when the engine speed exceeds a preset rotation speed (rl) of 1. , or other set rotation speed (r2)
Control was such that the air conditioner was turned off at the following times, and there was no control over changes in the air conditioner load applied to the engine.

In other words, when the air conditioner is operating and the engine load is shifted from the neutral range (N) to the drive range (D) depending on the size of the engine load, the load factor of the air conditioner is reduced and the engine stalls (hereinafter referred to as "engine stall"). ”) had not been proposed.

[Problems to be solved by the invention] Conventional problems However, in the control system described above, the engine speed (r2) at which the air conditioner is turned off is constant;
When the load on the air conditioner engine is large, for example, change the shift range from neutral (N) to drive (D).
) If a load change occurs on the engine due to the switching operation, there is a problem in that the engine speed drops or the engine stalls.

Purpose of the Invention The present invention was made to solve the above problem, and by controlling the air conditioner on and off according to the engine speed determined by the load of the air conditioner, it is possible to prevent the sudden decrease in the engine speed. The purpose of the present invention is to provide a vehicle air conditioner control system that can prevent engine stalling and engine stalling.

[Means and operations for solving the problem of interpolation] In order to achieve the above object, the present invention provides an air conditioner control system for a vehicle equipped with an automatic transmission, in which the compressor pressure of the air conditioner is detected and the system is controlled based on the pressure signal. A discrimination circuit that determines the engine rotation speed for on/off control of the air conditioner, detects the engine rotation speed, compares the rotation speed with the engine rotation speed determined by the discrimination circuit, and turns on and off the air conditioner according to the size of the load. An air conditioner control circuit for controlling the air conditioner.

With the above configuration, the present invention determines the engine speeds rL and r2 for on/off control of the air conditioner in the discrimination circuit based on the signal from the pressure sensor that detects the refrigerant pressure of the air conditioner compressor, and furthermore, Determined rotation speed rl.

By comparing r2 with the signal from the engine speed detection sensor, it is possible to automatically control the engine speed at which the air conditioner is turned on and off according to the magnitude of the load.

In the control of the present invention, when the air conditioner load applied to the engine is large, that is, when the refrigerant pressure of the compressor is large, the engine speed at which the air conditioner is turned off is set to a higher speed, and at this time, the air conditioner is turned on. The engine rotational speed is also controlled to be higher by a predetermined amount.

As described above, it is possible to prevent an abnormal drop in engine speed and engine stalling when the air conditioner is operating.

[Example code] Hereinafter, preferred embodiments of the present invention will be described based on the drawings.

FIG. 1 shows a schematic configuration of a vehicle air conditioner control system according to the present invention, and a vehicle to which the present invention is applied is provided with an automatic transmission.

Characteristic features of the present invention include a discrimination circuit that detects the compressor pressure of the air conditioner and determines the engine speed for on/off control of the air engine based on the pressure signal; The present invention includes an air conditioner control circuit that compares the engine speed determined by the circuit and controls the air conditioner on and off according to the size of the load.

That is, the control system of the present invention controls the air conditioner on and off based on the engine speed, and includes a pressure sensor 12 that detects the refrigerant pressure of the air conditioner compressor 10 and a rotation speed sensor 14 that detects the engine speed. Also, inside the air conditioner main amplifier 16,
A determination circuit 1 that determines the engine rotation speed for controlling the air conditioner on and off based on the input signal from the pressure sensor 12.
8, and an air conditioner control circuit 20 that performs on/off control of the air conditioner based on the output from the load circuit 18 and the signal from the engine speed detection sensor 14.

In the discrimination circuit 18, as shown in FIG.
Based on the refrigerant pressure signal from the pressure sensor 12, an engine rotation speed rl at which the air conditioner should be turned on and an engine rotation speed r2 at which the air conditioner should be turned off are determined. This engine rotation speed rl.

The optimum value for r2 is determined as a compatible value. For example, in FIG. 2, the engine rotation speed rl for air conditioner on/off control
Hysteresis is formed in r2, and the engine rotational speeds rL and r2 are set to change rapidly with the compressor pressure PO as a boundary. The compressor pressure PO in the figure indicates the compressor pressure at which engine stall occurs when the shift range is shifted from neutral (N) to drive (D), for example, to a high engine load side.

In the air conditioner control circuit 20, the engine speed characteristic (hysteresis) shown in FIG. The engine rotational speeds rl and r2 determined in step 1 and the signal input from the engine rotational speed sensor 14 are compared.

In the embodiment, when the engine speed detected by the speed sensor 14 is higher than the set speed r1, a magnetic clutch (not shown) of the air conditioner compressor 10 is connected to turn on the air conditioner, and on the other hand,
When the rotation speed becomes lower than the set rotation speed r2, the magnetic clutch is engaged and released, and the operation of the air conditioner is stopped. In this case, when the compressor pressure is high and the air conditioner load applied to the engine is large, the engine speed for on/off control of the air conditioner is set high, as shown by the broken line in FIG. 3, to ensure smooth idling.

In addition, in the discrimination circuit 18, as shown in FIG.
By providing a characteristic in which the engine speed increases in proportion to the magnitude of the refrigerant pressure in the compressor, it becomes possible to change the hysteresis at the same time as changing the engine speed. And the engine speed r for on/off control of the air conditioner.
1 rr2 may be determined by selecting an optimal relationship depending on the performance of the air conditioner and engine.

As shown in Figure 3, according to this embodiment, as shown in Figure 3,
It is possible to slide the engine speed characteristics for controlling the air conditioner on and off. In other words, in the past, the timing of cutting off the air conditioner was delayed when the air conditioner was under high load, resulting in a drop in engine speed or stalling due to a temporary load during shift range operation, for example. By sliding the number characteristics, the air conditioner cut timing is made earlier, and even if the engine speed decreases due to an increase in air conditioner load at high temperatures or shift range operation, the engine speed that controls the air conditioner can be changed. , it is possible to quickly recover by cutting off the air conditioner immediately after the engine speed drops.

Furthermore, as shown in FIG. 5, by increasing the engine speed r2 at which the air conditioner is stopped in an abnormally low pressure region or abnormally high pressure region, it is possible to detect abnormally low pressure due to gas leakage or abnormality based on the signal from the pressure sensor 12. A wide range of control is possible, including air conditioner cut control at high pressure.

In this case, the engine speed r2 on the air conditioner stop side is set near the maximum allowable engine speed.

[Effects of the Invention] As explained above, this invention controls the on/off of the air conditioner based on the engine speed, so that even when the engine is shifted to a high load while the air conditioner is operating, the engine It can effectively prevent abnormal drops in rotation speed and engine stalling.

[Brief explanation of the drawing]

Fig. 1 is a diagram showing a schematic configuration of a vehicle air conditioner control system according to the present invention, Fig. 2 is a diagram showing the relationship between compressor pressure and engine speed in the discrimination circuit, and Fig. 3 is a diagram showing the engine rotation speed in the air conditioner control circuit. Figure 4 is a diagram showing the relationship between compressor pressure and engine speed according to another embodiment. Figure 5 is a diagram showing the relationship between compressor pressure and engine speed when the pressure is abnormally high or low. FIG. 6 is a diagram showing conventional air conditioner control characteristics depending on engine speed. 10...Air conditioner compressor 12...Pressure sensor 14...Engine speed sensor 16...Air conditioner main amplifier 18...Discrimination circuit 20...Air conditioner control circuit

Claims (1)

[Claims] An air conditioner control system for a vehicle equipped with an automatic transmission includes a discrimination circuit that detects air conditioner compressor pressure and determines the engine speed for on/off control of the air conditioner based on the pressure signal; An air conditioner control system for a vehicle, comprising: an air conditioner control circuit that controls the air conditioner on and off according to the magnitude of the load by comparing the engine rotation speed determined by the discrimination circuit.