JPS623293Y2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a vehicle air conditioner that uses the driving force of an automobile engine to drive a cooling compressor, and more particularly to a compressor control device.

Conventionally, vehicle air conditioners use part of the engine power to drive the cooling compressor, which puts a strain on the engine when the air conditioner is running, making it necessary to climb hills or suddenly accelerate. Sufficient power performance may not be obtained under high loads such as Furthermore, even if a high-output engine provides a certain degree of acceleration, it results in a deterioration in fuel efficiency.

Therefore, devices have been proposed that temporarily stop the operation of the compressor when a vehicle requires sudden acceleration or high output above a certain level, allowing the vehicle to utilize its original power performance and preventing deterioration in fuel efficiency.

FIG. 1 shows a conventional example of this type of device.

In the figure, 1 is a switch that turns on and off the power to the air conditioner, 2 is a thermoswitch, 3 is a relay operated by a detection switch 5 or a manual switch 6, and 4 is an electromagnetic clutch that connects the cooling compressor and the engine. Detection switch 5
The engine consists of an accelerator switch that is connected to an accelerator pedal or a link and operates when the accelerator is depressed, and a negative pressure switch that detects engine load based on changes in intake manifold negative pressure.

However, when an accelerator switch is used as the detection switch 5, it is difficult to install it, and the operating point of the switch changes depending on how it is installed, so it lacks versatility and is not very reliable and practical. . Furthermore, in high-speed, high-load conditions where the accelerator is continuously depressed, or when climbing a slope, the electromagnetic clutch remains off for a long time, and the compressor does not operate and cannot perform its function as an air conditioner. On the other hand, even when a negative pressure switch is used as the detection switch 5, there is a similar problem.
As shown in the figure, a system is adopted in which a manual switch 6 is provided and directly operated by the driver to drive and stop the compressor. As another method, a method has been proposed in which a timer is used to automatically restore the compressor when the compressor is stopped for a certain period of time or more due to the operation of a detection switch.

In any case, in the case of a conventional manual switch, the driver (or passenger) of the vehicle must operate the manual switch after feeling discomfort. Even in the case where a timer is used, since it has nothing to do with the temperature control signal, there is a significant problem in terms of temperature controllability and comfort.

The present invention was developed in view of the above-mentioned problems, and it is possible to obtain sufficient power performance by temporarily stopping the operation of the compressor when the automobile is under high acceleration or under high load, and it also provides temperature control. The aim is to provide an air conditioning control device with excellent performance.

Examples of the present invention will be described below.

FIG. 2 is a diagram showing temperature changes when the air conditioner is operated. T is the temperature detected by a thermistor installed on the air outlet side of the refrigerant evaporator, etc., and decreases over time from the start of operation of the air conditioner, and the compressor is turned on between the changeable set temperature T ₀ and T ₁ . , turn it off to control the temperature.

FIG. 3 is a circuit configuration diagram of one embodiment of the present invention, which includes a temperature control circuit 10, a detection switch 54 such as a negative pressure switch for detecting a high engine load state and stopping the compressor, and this detection switch. A timer circuit 20 for delaying the detection signal of the detection switch 54, and a timer circuit 30 for restarting the compressor that has stopped due to the operation of the detection switch 54.
and a drive circuit 40 for the electromagnetic clutch 4.

The temperature control circuit 10 includes a bridge circuit composed of a thermistor 11 for detecting the temperature of the air blown from the refrigerant evaporator, a variable resistor 12 for setting a target temperature, and resistors _R1 to _R3 , and a bridge circuit that is divided from the bridge circuit. It is composed of a switching amplifier 13 operated by voltages V ₀ and V ₁ and a resistor R ₄ that sets the voltage difference between this amplifier 13.

Here, an explanation will be given of the operation when the detection switch 54 is closed in a normal running state without sudden acceleration. At the start of cooling operation, the blown air temperature T is higher than the set value. Therefore, the terminal voltage V ₁ of the thermistor 11 is high, and the compressor (electromagnetic clutch 4
2) is higher than the reference voltage V ₀ that defines the off-temperature. Therefore, the output of the amplifier 13 is at a high level, and the output of the amplifier 21 in the timer circuit 20 is also at a high level, so the outputs of the AND circuit 55 and the OR circuit 56 are at a high level, and the electromagnetic clutch 42 is energized via the relay 41. and the compressor is driven. When the blowout temperature T gradually decreases to the lower limit value T ₀ of the set temperature, V ₁ <V ₀ and the output of the amplifier 13 becomes low level, thereby stopping the compressor. Thereafter, when the blowout temperature T rises and reaches the upper limit value T ₁ , V ₁ >V ₀ again and the compressor is driven. In this way, temperature control is performed to keep the blown air temperature T within the set temperature range.

Next, for example, when a sudden acceleration operation is performed and the detection switch 54 is turned off, the capacitor _C1 is quickly discharged in the timer circuit 20 (charging time>discharging time), and the output of the switching amplifier 21 becomes low level. As a result, the temperature control circuit 1
0, that is, regardless of the output of the amplifier 13, the AND circuit 55 becomes low level, the compressor stops, and the original acceleration performance of the automobile is obtained. This also applies to the accelerator operation when climbing a slope.

Note that when the sudden acceleration state etc. is canceled, the detection switch 54
When turned on, the output of amplifier 21 becomes high level with a delay of the charging time to capacitor _C1 ,
The compressor is controlled based on the output of temperature control circuit 10. In this way, in the timer circuit 20, the compressor is driven with a predetermined time delay after the detection switch 54 is turned on, so even if the detection switch 54 causes chattering, for example, the compressor is turned on frequently. , there will be no inconvenience such as being turned off.

If the engine is under continuous high load,
The detection switch 54 continues to be in the OFF state, and the blown air temperature T rises. (Dotted line in Figure 2) When the blown air temperature T rises and exceeds the temperature T ₂ (temperature defined by the voltage V' ₀ ) which is slightly higher than the upper limit of the set temperature T ₁ , V' ₀ < V ₁ . , the output of the switching amplifier 51 becomes high level. At this time, the output of the amplifier 21 is at a low level, the output of the inverter 53 is at a high level, and the output of the AND circuit 52 is at a high level. In the timer circuit 30, after the output of the AND circuit 52 becomes high level, the output of the switching amplifier 31 becomes high level after a predetermined time determined by the capacitor C ₂ and the resistors R ₉ to _{R 12} has passed, and the output of the switching amplifier 31 becomes high level, and the output of the switching amplifier 31 becomes high level. is driven back.

In this way, when the detection switch 54 is in the OFF state and the outlet temperature T is the upper limit of the set temperature range,
When it becomes higher than T ₂ , the timer circuit 30 is activated and the compressor is driven back after a predetermined period of time.
Therefore, the discomfort caused by the rise in temperature inside the vehicle is kept to a minimum. Note that in the timer circuit 30,
Once the output of the amplifier 31 becomes high level, the blown air temperature T decreases to become T<T ₂ , the output of the amplifier 51 becomes low level, and the high level output of the amplifier 31 is maintained. this is a capacitor
This is realized by a combination of _C1 and diodes 32-33. That is, the non-inverting terminal input voltage of the amplifier 31 is such that even if the output of the AND circuit 52 becomes low level, unless the output of the amplifier 13 or the output of the inverter 53 becomes low level, the capacitor C ₂ will not discharge and will remain at a constant voltage. Since it is retained,
The amplifier 31 will maintain a high level output. Then, if the blowing air temperature T is T≦T ₀ , that is, the output of the amplifier 13 in the temperature control circuit 10 becomes low level, or the detection switch 54 is closed and the output of the amplifier 21 in the timer circuit 20 becomes high level. When the output of the inverter 53 changes to low level, the capacitor _C2 is discharged, and the high level output of the amplifier 31 is canceled.

By the way, in a conventional system in which the timer is operated only by the signal from the detection switch 54 and the compressor is reset after a certain period of time, the compressor operates regardless of the blown air temperature T, so that the temperature is sufficiently within the control temperature range. This results in an unnecessary return operation even though it exists. In addition, since the timer setting time needs to be relatively long, if the detection switch 54 is opened when the blowout air temperature T is close to T ₂ (T < T ₂ ), the compressor will be in a stopped state for a long time, causing discomfort. They will be forced into a difficult situation. On the other hand, according to the present invention, the above-mentioned disadvantages can be solved and the performance of the automobile can be fully demonstrated. Furthermore, it is possible to provide a control device that has excellent temperature controllability, is inexpensive, and has a simple structure.

It should be noted that the circuit shown in FIG. 3 is just one example, and it goes without saying that each component can be realized with other circuit configurations having similar functions without major changes.

[Brief explanation of the drawing]

Figure 1 is a conventional compressor drive control circuit diagram.
FIG. 2 is a diagram showing changes in the temperature of the blown air over time under normal operating conditions, and FIG. 3 is a circuit diagram of an embodiment of the present invention. In the figure, 10 is a temperature control circuit, 20 is a timer circuit, 30 is a timer circuit, 40 is an electromagnetic clutch drive circuit, 41 is a relay, 42 is an electromagnetic clutch, and 54
is the detection switch.

Claims (1)

[Scope of Claim for Utility Model Registration] 1. A temperature control circuit that compares a signal from a temperature detector with a signal based on a target set temperature and controls the drive of a cooling compressor according to the comparison result, and A control device for a vehicle air conditioner, comprising a detection switch that detects acceleration or a high load state of the engine, and a circuit that stops the compressor by giving priority to the detection signal of the detection switch over the output signal of the temperature control circuit, Operates when the detected temperature becomes higher than the upper limit of the target set temperature while the detection signal from the detection switch is being output, and outputs a signal to return the compressor when a predetermined period of time has elapsed after the start of operation. A control device for a vehicle air conditioner, characterized in that the control device has a timer circuit that simultaneously holds the output of the timer circuit, and is configured to release the output holding of the timer circuit in response to an output signal of the temperature control circuit or a detection signal from the detection switch. . 2. Utility Model Registration Scope of Claim 1: The control device for a vehicle, characterized in that the circuit for stopping the compressor has a timer function for delaying the detection signal of the detection switch for a predetermined period of time. control device.