JPH0717144B2 - Vehicle air conditioner - Google Patents

Description

The present invention relates to a vehicle air conditioner.

(Prior Art) A recent vehicle is provided with an air conditioner that dehumidifies the interior of the vehicle and automatically adjusts the temperature to a desired temperature.

In a conventional air conditioner, the target air outlet temperature is calculated from a predetermined heat balance equation based on the outside air temperature, the vehicle interior temperature, the amount of solar radiation, the vehicle interior set temperature, and the like, and the air volume is calculated, and based on the calculated target air outlet temperature. Calculate the opening of the air mix door and control the opening of the air mix door to the calculated opening value to adjust the temperature of the air blown into the passenger compartment to obtain the desired passenger compartment temperature. I have
59-48169).

By the way, in order to prevent a problem such as blowing out cool air while the engine water temperature is still low in winter, for example, a water temperature sensor dedicated to an air conditioner that detects the temperature of the engine cooling water is conventionally provided. The amount of air blown out is controlled by the output (Japanese Patent Publication No. 60-21082).

On the other hand, in the vehicle, a water temperature sensor that detects the temperature of the engine cooling water is provided separately from the air conditioner in order to prevent the engine from heating, and the output of this sensor is used to display the water temperature on the engine water temperature gauge, It also warns when something is wrong.

Thus, conventionally, two water temperature sensors are used for different purposes, but this also causes a cost increase.

Therefore, it is conceivable to use the engine water temperature sensor for both purposes, but if the engine water temperature sensor is connected to the arithmetic unit of the air conditioner that calculates the target outlet temperature, air mix door opening, air volume, etc. required for air conditioning, the input impedance Is small, there is a problem that the leakage current from the engine water temperature gauge becomes large.

(Object and Structure of the Invention) The present invention has been made in view of the above points, and an object thereof is to eliminate the need for a water temperature sensor used in an air conditioner without passing a leakage current, and to achieve this object, First
As shown in the overall configuration of the figure, the blowout temperature is calculated based on at least the vehicle interior temperature signal and the vehicle exterior temperature signal, the blowout air volume is calculated based on the engine water temperature, and the blowout port is calculated based on the blowout temperature calculated value. In a vehicle air conditioner having a calculating means for determining a mode, the blowout mode switch is turned on when the determined blowout mode is foot blowing or both foot and chest blowout, and is turned off when the mode is less than that, the engine A water temperature sensor for detecting water temperature and the arithmetic means are connected.

(Example) Hereinafter, the present invention will be described with reference to the drawings.

FIG. 2 is a block diagram of an embodiment of the air conditioner according to the present invention according to the present invention, and this embodiment uses an engine cooling water temperature sensor.

In the figure, 1 is a water temperature sensor that detects the temperature of engine cooling water, for example a thermistor, 2 is an engine water temperature gauge that displays the engine cooling water temperature using the output from this water temperature sensor 1, and 3 is a water temperature sensor 1. A mode switch which is connected between the connection point A with the engine water temperature gauge 2 and the arithmetic unit 4 and which is automatically switched depending on the outlet mode.
Reference numeral 5 is an air conditioner switch that is turned on when air conditioning is required, 6 is temperature sensors for detecting outside air temperature, vehicle interior temperature, solar radiation amount, intake air temperature, etc. 7 is a room temperature setting device for setting vehicle interior temperature .

The arithmetic unit 4 includes a target outlet temperature arithmetic circuit 41 that calculates a target outlet temperature based on a predetermined arithmetic expression from the temperature signal output from the temperature sensors 6 and the temperature signal set by the room temperature setting unit 7, The air mix door opening degree calculation circuit 42 that calculates the air mix door opening degree based on the calculated target blow temperature, the air volume calculation circuit 43 that calculates the blown air volume based on the engine water temperature, and the calculated target blow temperature Based on this, there is provided an air outlet determination circuit 44 which determines whether the air outlet is located at the feet, at the chest, or directly below the front window (so-called defroster).

8 is an actuator that adjusts the opening of the air mix door 9 based on the calculated opening value by the air mix door opening calculation circuit 42, and 10 is the rotation speed of the blower fan motor 11 based on the calculated air flow value by the air flow calculation circuit 43. Drive circuit, which changes
Reference numeral 12 is an outlet switching actuator that switches the outlet 13 based on a signal from the outlet determination circuit 44.

The output of the water temperature sensor 1 (that is, the voltage at the connection point A) is passed through the mode switch 3 and the high resistance R of, for example, 5 KΩ or more.
Is input to the air volume calculation circuit 43 of the calculation device 4 via.

When the air conditioner switch 5 is turned on, the target outlet temperature calculating circuit 41 in the arithmetic unit 4 calculates the target outlet temperature based on the temperature signals from the temperature sensors 6 and the room temperature setter 7. Further, the air mix door calculation circuit 42 calculates the air mix door opening from this target blowout temperature calculation value, and the actuator 8 adjusts the opening of the air mix door 9 to this opening calculation value.

On the other hand, the mode switch 3 is connected to the contact a when the air outlet is in the foot or both the foot and chest air blowing modes in response to a signal from the air outlet determining circuit 44 of the arithmetic unit 4, and the air outlet is connected to the chest. (VENT) or defroster (DEF) is switched to contact b. As a result, the output of the water temperature sensor 1, that is, the voltage at the connection point A, is input to the arithmetic unit 4 via the high resistance R only in the foot blowing mode, that is, when the blowing air temperature is relatively high, so that almost no leakage current flows. Absent. On the other hand, in the chest blowing mode and the defroster mode, since the mode switch 3 is connected to the contact b, the leakage current from the engine water temperature gauge 2 does not flow.

Although the water temperature sensor for the engine water temperature gauge is used in the above embodiment, a water temperature sensor for engine control may be used instead.

Further, in the above-mentioned embodiment, the arithmetic unit 4 is configured to perform each function by a circuit block, but a microcomputer may be used, and a flow chart which is a characteristic part of the present invention in that case is shown in FIG.

(Effects of the Invention) As described above, according to the present invention, the output of the water temperature sensor is calculated through the mode switch that is turned on only in the foot blowing mode or the foot / chest blowing mode in which the blowing air temperature is relatively high. Since it was configured to connect to the device,
By using only one water temperature sensor, it is possible to provide an air conditioner that does not flow a leakage current at low cost.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is an overall configuration diagram of a vehicle air conditioner according to the present invention, FIG. 2 is a block diagram of an embodiment of a vehicle air conditioner according to the present invention, and FIG. It is a flow chart explaining operation by microcomputer processing of an air-conditioner. 1 ... Water temperature sensor, 2 ... Engine water temperature gauge, 3 ... Mode switch, 4 ... Computing device, 6 ... Sensors, 7 ... Room temperature setting device,
9 ... Air mix door, 13 ... Air outlet, 44 ... Air outlet determination circuit

Claims (2)

[Claims] 1. A blowout temperature is calculated based on at least a vehicle interior temperature signal and a vehicle exterior temperature signal, a blowout air volume is calculated based on an engine water temperature, and an outlet mode is determined based on the blowout temperature calculated value. In a vehicle air conditioner having a computing means, ON when the determined outlet mode is foot outlet or both foot and chest outlet
However, the vehicle air conditioner is characterized in that the water temperature sensor for detecting the engine water temperature and the calculation means are connected via an outlet mode switch that is turned off when the temperature is lower than that. 2. A vehicle air conditioner according to claim 1, wherein a high impedance element is connected between the air outlet mode switch and the computing means.