JPS6261453B2 - - 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 is accelerating, compressor operation is stopped in order to reduce the load on the engine and accelerate acceleration. The compressor is driven after a set 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 increases, which significantly reduces the feeling for the occupants. Therefore, the present applicant has filed an application for an invention as described below (unknown to the public).

In FIG. 1, a blower 2 for introducing inside air or outside air is installed on the upstream side, an evaporator 3 is installed on the downstream side of the blower 2, and a heater core 5 is connected downstream of the evaporator 3 via an air mix door 4. The main body of the duct is provided with a rotatable mode switching door 6.
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 13 is configured as shown in FIG. 2, for example, and can be formed using a microcomputer. This control section 13 is controlled by signals from an acceleration detection switch 15 that detects the acceleration driving state of the vehicle, a temperature sensor 16 that detects the temperature on the surface side of the evaporator 3 or the vicinity thereof, and a compressor switch 17. Drive circuit 14 or inside/outside air switching door 4
5. Sends a signal 19 for controlling the opening degree of the air mix door 4, 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 relay 21 is connected to the collector side of a PNP type transistor 23 and is energized or deenergized by this transistor 23. The temperature sensor 16
The connection point between and resistor 23 is connected to the inverting input side of an operational amplifier 25 via a resistor 24, and 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 connected to the clock pulse input terminal of the flip-flop 26 via resistors 31 and 32, an inverting circuit 33, a capacitor 34, and a diode 35. The drive side input terminal D of this 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 compressor 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 together with the resistor 31, forms a noise prevention circuit (low-pass filter). 39 is a diode whose cathode side is connected to the anode side of the capacitor 34 and the diode 35, and whose 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. be. 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. Further, 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 while the compressor switch 17 is 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 generated as shown in FIG. As shown in FIG. 3, it becomes L level, and during this time, the input of the inverting circuit 33 decreases due to discharge through the resistor 31 of the capacitor 38 and the switch 15, and drops to a predetermined level.On the contrary, the output of the inverting circuit 33 rises and reaches a predetermined level. When it rises to the level of , diode 3
5 is turned on, capacitor 34 is instantaneously discharged through resistor 40, resulting in the trigger pulse shown in FIG. Since the output of Q is set to L level, the output is inverted to H level based on the signal supplied to the clock pulse input terminal, transistor 23 is turned off, relay 21 is deenergized, and switch 22 is turned off. It is turned off, the magnetic clutch 12 is deenergized, and the operation of the compressor 7 is stopped. Note that the capacitor 38 has a small capacity and has a small time constant between it and the resistor 31. Therefore, when controlling the compressor, the trigger pulse shown in FIG.
It can be considered that this occurs almost simultaneously with the drop from level to L level. This allows cooling cycle 1
1 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, as the compressor is stopped, the temperature of the evaporator 3 rises, and the temperature tm on or near the surface side of the evaporator 3 rises to reach the set temperature T, so that the resistance value of the temperature sensor 16 becomes smaller. When the signal obtained from the connection point between the temperature sensor 16 and the resistor 23 becomes smaller and reaches the set level, the output of the operational amplifier 25 becomes H level, and an H level signal is supplied to the clear input terminal of the flip-flop 26. Therefore, the signal sent from the output terminal of flip-flop 26 is 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 compressor is controlled based on detecting the temperature on or near the surface of the evaporator 3, the outlet temperature or the temperature in the vehicle compartment will not rise excessively.

However, in a normal air conditioner, when the outside air temperature is low, the heat load is small, so the temperature inside the duct is also low, making it difficult for the evaporator temperature to rise.
Based on operation 3, if the compressor is turned off during acceleration, the evaporator temperature will not reach the set temperature T even after a long period of time, and the compressor will not be turned back on. Therefore, even if an attempt is made to turn on the compressor switch 17 to drive the compressor in order to remove indoor moisture or moisture adhering to the inner surface of the window glass when the outside temperature is low, the compressor will not be turned on and no demist effect will be obtained.

Therefore, in the present invention, as shown in FIGS. 5 and 6, the connection point between the sensor 50 that detects the outside air temperature ta and the resistor 51 is connected to the inverting input side of the operational amplifier 53 via the resistor 52. , the connection point between resistors 54 and 55 is connected to the non-inverting input side of the operational amplifier 53 via a resistor 58, the output side of the operational amplifier 53 is connected to the cathode side of a diode 56, and the anode side thereof is connected to the resistor 24. Connect to.

According to such a configuration, the outside air temperature ta becomes lower than the set temperature t ₁ (corresponding to the voltage at the connection point between the resistors 54 and 55), the output voltage of the sensor 50 increases, and the voltage at the connection point between the resistors 54 and 55 increases. When the voltage exceeds the voltage, the output of the operational amplifier 53 as a comparator becomes L level and the diode 56 is turned on, so the potential on the inverting input side of the operational amplifier 25 is lowered toward the L level, and the output of the operational amplifier 25 becomes is H
Since it is held at the level, transistor 23 is turned on and switch 22 is turned on. Therefore,
By turning on the compressor switch 17, the compressor 7 can be driven when the outside air temperature is low, so that moisture in the vehicle interior and the window glass can be removed. Note that, due to the operation of the operational amplifier 53, acceleration cut is not performed when the outside air temperature is low, but since the operating rate of the compressor is low when the outside air temperature is low, this poses little problem in terms of power saving.

In addition, in the present invention, instead of the acceleration detection switch,
A speed detection switch may be used to turn the compressor back on at high speeds. Furthermore, it goes without saying that the present invention can be implemented using a microcomputer or a computer.

As explained above, according to the present invention, in a vehicle air conditioner that detects the driving state such as acceleration or speed of the vehicle and turns off the compressor, the temperature on the surface side of the evaporator or the vicinity thereof is controlled. Based on the output signal of the detected temperature sensor, the operation of the compressor that has been turned on is restored, and the compressor is also turned on even when the outside temperature is lower than the set temperature, so the temperature inside the vehicle or It is possible to prevent fluctuations in the temperature of the air blowing from the vehicle air conditioning system, improve the feeling of the occupants, reduce the load on the engine, and enable smooth acceleration and high-speed driving. Obtainable.

[Brief explanation of the drawing]

1 and 2 are simplified configuration diagrams and circuit diagrams showing one embodiment of the vehicle air conditioner proposed by the present inventor, and FIGS. 3 and 4 a to 4e are the vehicle air conditioners described above. Flow chart and time chart for explaining the operation of the device. FIGS. 5 and 6 are a circuit diagram and a flow chart showing one embodiment of the vehicle air conditioner according to the present invention. 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, 50... operational amplifier, 26... flip-flop, 50... outside air sensor.

Claims (1)

[Claims] 1. In a vehicle air conditioner that turns off a compressor based on the output of a detection unit that detects driving conditions such as acceleration or speed of the vehicle, the temperature of the surface side of the evaporator or the vicinity thereof is An air compressor for a vehicle, characterized in that it is provided with a control unit that restores the operation of the compressor based on the output signal of a temperature sensor to be detected, and is also provided with an outside air temperature detection circuit, and is capable of turning on the compressor using the output of the circuit. harmonization device. 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. .