JPS6313849B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a vehicle air conditioner, and more particularly to a vehicle air conditioner that controls a compressor during acceleration of the vehicle.

Conventionally, when a vehicle accelerates, the compressor operation is stopped in order to reduce the load on the engine and accelerate the acceleration. The compressor is driven after a certain amount of time has elapsed.

However, according to such a vehicle air conditioner, the time during which the compressor is turned off when the vehicle accelerates is set in advance, so the blowing temperature when the compressor is turned off varies depending on the outside air temperature and the indoor temperature. This has the disadvantage that the blowing temperature fluctuates, which significantly reduces the feeling for the occupants.

Therefore, an object of the present invention is to eliminate the above-mentioned drawbacks by controlling the off-operation of the compressor by detecting the temperature of the cooler, and will be described in detail below using examples.

FIG. 1 is a simplified configuration diagram showing an embodiment of a vehicle air conditioner according to the present invention, and in the same figure,
1 is a blower 2 that introduces inside air or outside air into the upstream side;
An evaporator 3 is installed downstream of the blower 2, and a heater core 5 is connected downstream of the evaporator 3 via an air mix door 4.
This is a duct main body in which a mode switching door 6 is rotatably provided. The evaporator 3 is cooled by a cooling cycle 11 comprising a compressor 7, a condenser 8, an evaporator 9, and an expansion valve 10. Further, the compressor 7 is controlled by a magnetic clutch 12, which is controlled by a drive circuit 14 which is controlled by a control section 13. The control section 1
3 is configured as shown in FIG. 2, for example,
This can be created using a microcomputer. The control unit 13 includes an acceleration detection switch 15 that detects the acceleration driving state of the vehicle, a temperature sensor 16 that detects the temperature on or near the surface of the evaporator 3, and a compressor switch 1.
The drive circuit 1 is controlled by a signal from 7.
4 or sends out a signal 19 for controlling the opening degree of the inside/outside air switching door 45, the air mix door 4, the mode switching door 6, etc. In Fig. 2, one end of the compressor switch 17 is connected to a power supply 20, and the other end is turned off when the evaporator temperature drops to a set value, and is activated by a defrost thermoswitch 18 and relay 21 to prevent freezing. It is connected to the magnetic clutch 12 via a switch 22 that operates. The above relay 21 is PNP
connected to the collector side of the type transistor 23,
It is energized or deenergized by this transistor 23. A connection point between the temperature sensor 16 and the resistor 23 is connected to an operational amplifier 25 via a resistor 24,
The output side of this operational amplifier 25 is connected to the clear input terminal side of a flip-flop 26. Note that a connection point between resistors 27 and 28 is connected to the non-inverting input side of the operational amplifier 25 via a resistor 29, thereby supplying a reference voltage. The connection point between the acceleration detection switch 15 and the resistor 30 is the resistor 31, 3.
2 inverting circuit 33, capacitor 34, diode 3
5 to the clock pulse input terminal of flip-flop 26. A drive-side input terminal D of the flip-flop 26 is connected to the compressor switch 17, and one output terminal Q thereof is connected to the base side of the transistor 23 via a resistor 36. Note that a resistor 37 is connected between the base side of the transistor 23 and the collector switch 17. A capacitor 38 has one end connected to the connection point between the resistors 31 and 32 and the other end grounded, and forms a noise prevention circuit (low-pass filter) with the resistor 32. 39 is on the cathode side,
A diode is connected to the anode side of the capacitor 34 and the diode 35, and its anode side is grounded. 40 is a resistor whose one end is connected between the diode 35 and the flip-flop 26, and whose other end is grounded. The acceleration detection switch 15 may be, for example, a pressure switch that detects the pressure in the intake pipe of the engine, a switch that detects the position of an accelerator, or a switch that detects the position of an accelerator link linked to the accelerator. Also,
The temperature sensor 16 is attached directly to or near the evaporator 3.

The operation of the vehicle air conditioner with the above configuration will be explained below with reference to FIGS. 3 and 4. First, when the vehicle accelerates with the compressor switch 17 turned on, the acceleration detection switch 15 is turned on, and the signal S obtained from the connection point between the acceleration detection switch 15 and the resistor 30 is As shown in the figure, when it becomes L level, capacitor 3
8 is instantly discharged, the potential on the input side of the inverting circuit 33 suddenly drops, and the potential on the output side suddenly rises.
This corresponds to applying a voltage to the input side of the differential circuit formed by the capacitor 34 and the resistor 40, and at this time, a signal having the waveform shown in FIG. 4b as a differential pulse is supplied to the terminal CP. Since the above operation is performed instantaneously, it can be considered that the differential pulse is generated almost simultaneously when the signal S becomes L level. Note that the diode 39 supplies only the positive differential pulse to the terminal CP. As a result, since the output of the flip-flop 26 is normally set to the L level at its output terminal Q, its output is inverted to the H level based on the signal supplied to the clock pulse input terminal, and as a result, the transistor 23 is turned on. The relay 21 is turned off, the switch 22 is turned off, the magnetic clutch 12 is deenergized, and the operation of the compressor 7 is stopped. As a result, the operation of the cooling cycle 11 is stopped, and the cooling operation of the evaporator 3 is stopped. In this way, when the vehicle is accelerating, the compressor is stopped, so the load on the engine that drives the compressor is reduced, and the vehicle can be smoothly accelerated. Next, based on the above compressor being stopped, the evaporator 3
temperature increases, and the temperature on or near its surface increases.
As tm reaches the increased T, the resistance value of the temperature sensor 16 becomes smaller, and therefore the signal obtained from the connection point between the temperature sensor 16 and the resistor 23 becomes smaller, and when it becomes smaller to the set level, the operational amplifier 25 The output of the flip-flop 26 becomes H level, and the clear input terminal of the flip-flop 26 receives an H level.
Since the level signal is supplied, the signal sent from the output terminal of the flip-flop 26 is inverted to the L level, and the compressor is turned on again. Therefore, even if the vehicle continues to accelerate or run at high speed for a long time, the temperature sensor 16 detects the temperature on or near the surface of the evaporator 3, and if the temperature becomes higher than the set level, the control unit 13 activates the compressor 7. Since the system is turned on, the temperature inside the vehicle can be prevented from becoming unnecessarily high, and there is no risk of deteriorating the passenger's feeling. Furthermore, since the copressor is controlled based on detecting the temperature on the surface side of the evaporator 3 or in the vicinity thereof, the outlet temperature or the temperature inside the vehicle compartment will not rise excessively.

In addition, in the present invention, instead of the acceleration detection switch,
A speed detection switch may be used to turn on the compressor at high speeds.

As explained above, according to the present invention, in a vehicle air conditioner that turns off a compressor by detecting the acceleration or high-speed driving state of the vehicle, the temperature on or near the surface of the evaporator is detected. Since the operation of the compressor is restored based on the output signal of the temperature sensor, it is possible to prevent the temperature inside the vehicle interior or the temperature blown from the vehicle air conditioner from fluctuating, thereby improving the feeling of the occupants. At the same time, the load on the engine can be reduced, and acceleration and high-speed running can be performed smoothly.

[Brief explanation of the drawing]

1 and 2 are simplified configuration diagrams and circuit diagrams showing one embodiment of the vehicle air conditioner according to the present invention, and FIGS. 3 and 4 a to 4e show the operation of the vehicle air conditioner according to the present invention. These are a flow chart and a time chart for explaining. 3... Evaporator, 7... Compressor, 1
2...Magnetic clutch, 13...Control unit, 1
5... Acceleration detection switch, 16... Evaporator temperature sensor, 17... Compressor switch, 2
5... operational amplifier, 26... flip-flop.

Claims (1)

[Claims] 1. Turning off the compressor based on the output of a detection unit that detects the acceleration or speed of the vehicle,
A vehicle air conditioner designed to reduce the load on the engine is characterized by being provided with a control unit that restores the off-operation of the compressor based on the output signal of a temperature sensor that detects the temperature on or near the surface of the evaporator. Air conditioner for vehicles. 2. The air conditioner for a vehicle according to claim 1, wherein the operating state detection unit is constituted by a pressure switch that detects the pressure in the intake pipe of the engine, a switch that detects the position of the accelerator pedal, or both of these switches. .