JPS598521A - Control method of air conditioner for vehicle - Google Patents

Abstract

PURPOSE:To improve an air conditioning feeling, by setting an integrated signal to a maximum room cooling mode when an evaporator temperature reaches a minimum level in the method which controls air conditioning by an internal air temperature and the integrated signal obtained from a setting value of the internal air temperature. CONSTITUTION:An air conditioner is operated such that an integrated signal T is obtained in an arithmetic circuit 13 from output signals of a temperature setter 14, external air temperature sensor 15, internal air temperature sensor 16, etc., and a reference signal l1 of a reference signal output circuit 12 is controlled by said integrated signal T. Then a compressor 7 is controlled by a compared result of this reference signal l1 with a temperature signal tM of a sensor 6. Here said signal T is compared in a comparator circuit 17 with a cooler mode setting signal T2 being the signal T, when a temperature level L of an evaporator 2 set by a variable resistor 19 becomes a minimum level, and on the basis of this compared result, a gain of each control element 14-16 is adjusted through a gain regulating circuit 18, and the signal T is increased by a fixed level.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for controlling a vehicle air conditioner, and particularly to controlling an air mix door.

Recent vehicle air conditioning systems obtain a comprehensive signal by calculating the output signal of a temperature setting device and each output signal from elements such as an outside air temperature sensor, an inside air temperature sensor, and an autopsy sensor. Based on the magnitude of this overall signal, the air mix door, compressor, air blow-out (~mode switching door, etc.) are controlled. For example, when the temperature setting device is set toward high temperature, the overall signal becomes small and the air The mix door is controlled in the heater mode direction, the operating rate of the compressor is reduced, and the mode switching door is set to foot blow (~ mode).Also, when the temperature sensed by each sensor such as the outside air temperature sensor becomes high, the overall signal is The large air mix door is controlled to the cooler mode, the operating rate of the compressor is increased, and the mode switching door is set to the face blowing mode.

FIG. 1 is a block diagram showing an example of a control device for controlling the air mix door, compressor, etc., and in the same figure, l is a duct, 2 is an evaporator, 3 is a heater core, and 4 is an air mix door. , 5 is an actuator for controlling the air mix door, 6 is a sensor that detects the temperature on or near the surface of the evaporator 2, 7 is a compressor controlled by a switch 9 that is turned on and on by a relay coil 8, and 10 is a magnet for exciting the relay coil 8. a switching transistor to be deenergized, 11 a comparison circuit for controlling the transistor 10 on and off, 12 a reference signal output circuit for outputting a reference signal l to the comparison circuit 11, 13 a temperature setting device 14, an outside temperature sensor 15; This is a calculation circuit that calculates the total signal T by calculating the output signals of the inside air temperature sensor 16 and the like.

In such a configuration, when the temperature setter 14 is set toward a higher temperature or when the temperature sensed by each of the temperature sensors 15, 16, etc. becomes lower, the total signal T becomes smaller. In addition, the temperature setting device 14 is set to a low temperature direction, or each temperature sensor 15
, 16 increases, the total signal T changes to become larger.

FIGS. 2(a) and 2(b) are diagrams showing the control characteristics of the air mix door 4 and compressor 7 with respect to changes in the above-mentioned overall signal T. Here, the comparison circuit 11 turns off the transistor 10 when the sensing temperature of the sensor 6 becomes low and its output signal tM decreases in proportion to this and reaches the reference signal Jl (off level), thereby turning off the relay. Coil 8 is deenergized, contact 9 is turned off, and compressor 7 is turned off. When the compressor 7 is turned off, the temperature sensed by the sensor 6 increases, and its output signal tM increases,
This is the reference signal l, the weaker and the larger reference signal p,
(on level), the transistor 10 turns on,
Compressor 7 is turned on. By repeating this operation, the temperature of the evaporator 2 is maintained at a predetermined temperature level L. Note that, due to the hysteresis characteristic of the comparison circuit 11, the reference signal l is always held at a value that is slightly larger than that of the reference signal.

Here, the reference signal output circuit 12 is controlled by the total signal T of the arithmetic circuit 13, and the reference signal 1. ．． 1. As shown in Fig. 2(b), the total signal T is T
It is a constant value up to , but gradually decreases when it exceeds T, and after reaching T2, it becomes constant at a low level. Therefore, the temperature level L is also T1! , and decreases from T1 to T, and from T, onwards, it becomes constant at a low level.

The actuator 5 for the near mix door system M1 controls the opening degree θ of the air mix door 4 based on the overall signal T. That is, as shown in Fig. 2 (a), the opening degree θ is at its maximum (full heater mode) until the total signal T reaches T, but gradually decreases when it exceeds T1, and reaches its minimum (full heater mode) when it reaches T. cooler mode).

When the total signal T becomes T2 in this manner, the temperature level L of the evaporator 2 becomes the lowest, the opening degree θ of the air mix door 4 becomes the minimum, and the vehicle air conditioner operates in the full cooler mode.

However, according to the conventional vehicle air conditioner, the opening degree θ of the air mix door 4 is limited due to errors in the operating characteristics of the air mix door control actuator 5, friction of the rotating shaft portion of the air mix door 4, etc. The characteristic m does not become ideal, and as shown by characteristic n, changes to a value that is a little less than 7 times larger than the characteristic m. Therefore, even if the overall signal T becomes the full cooler mode setting signal T,
The opening degree θ of the air mix door 4 does not reach the minimum, therefore,
This system has a disadvantage in that the vehicle air conditioner cannot be completely set to full cooler mode. In other words, when the overall signal T increases from T to T, the opening degree θ of the air mix door 4 reaches its minimum, so the full cooler mode cannot be set completely and the feeling deteriorates. T,! ,cormorant.

[7] Therefore, the purpose of the present invention is to forcibly set the full cooler mode by increasing the magnitude of the total signal T to T8 or more when the total signal T reaches the signal T for setting the cooler mode. This will be explained in detail below using examples.

FIG. 3 is a block diagram showing an embodiment of the control method for a vehicle air conditioner according to the present invention, and the same parts as in FIG. 1 are denoted by the same reference numerals. In the figure, reference numeral 17 compares the total signal T from the arithmetic circuit 13 and the full cooler mode setting signal T, and when the total signal T becomes equal to the signal T, the gain adjustment circuit 18 controls the Signal S2
This is a comparison circuit that outputs .

The above-mentioned cooler mode setting signal ↑2 means the above-mentioned comparison circuit 11.
This is the magnitude of the total signal T when the reference signal l of the evaporator 2 is at the lowest level and the temperature level L of the evaporator 2 is at the lowest level, and this signal T2 is set in advance by the variable resistor 19, for example.

The gain adjustment circuit 18 outputs a signal L2, for example, a temperature setting device 14, an outside air temperature sensor 15, and an inside air temperature sensor 1.
By adjusting the gain of 6 etc., the total signal T is kept constant and increased by Bell M, so that the total signal T becomes T.

If so, let T be 10M, and let the total signal T be greater than or equal to T. That is, the total signal T is expressed by the following equation.

T-αTD-βta-γtr (where α, β, and γ are gains + TD is the output signal of the temperature setting device 14, ta is the output signal of the outside air temperature sensor 15, and tr is the output signal of the inside air temperature sensor 16) Therefore, by increasing the values of α, β, and γ, it is possible to keep the total signal T constant and increase it by M.

According to the above configuration, the total signal T gradually increases to T,
When the signal SI is reached, the comparison circuit 17 outputs a signal SI.
As a result, the gain adjustment circuit 18 operates and outputs the signal L2, and the total signal T2 is increased to 78 or more, so the air mix door control actuator 5 adjusts the opening degree θ of the near mix door 40 based on this signal T8. 0, that is, full cooler mode.

Therefore, according to the present invention, since the opening degree θ of the air mix door is always set to 0 when the temperature of the evaporator 2 reaches the lowest level, the vehicle air conditioner can be operated in full cooler mode. I can do it. Therefore, it is possible to prevent a deterioration in the feeling due to the maximum amount of cold air being blown out, and in addition, in the full cooler mode, a part of the air cooled by the evaporator 2 leaks from between the air mix door 4 and the duct 1, and the heater core 3 There is no problem of energy loss caused by heating.

In the present invention, as a method for increasing or decreasing the total signal T, an adjusting means such as a variable resistor may be provided at the output stage of the arithmetic circuit 13, and this may be adjusted.

[Brief explanation of the drawing]

Figure 1 is a block diagram showing an example of a conventional control method for a vehicle air conditioner, Figures 2 (a) and (b) are characteristic diagrams illustrating the operation of the vehicle air conditioner, and Figure 3. 1 is a block diagram showing an embodiment of a method for controlling a vehicle air conditioner according to the present invention. FIG. DESCRIPTION OF SYMBOLS 1... Tough 1-12... Evaporator, 3... Heater core, 4... Air mix door, 5... Air mix door control actuator, 7... Compressor, 11.17... Comparison circuit, 13... arithmetic circuit,
18... Gain adjustment circuit, 19... Variable resistor. Patent applicant: Agent of Diesel Kiki Co., Ltd.
Patent attorney Jun Miyazono −

Claims (2)

[Claims] (1) In a vehicle air conditioner that controls a compressor control means and an air mix door control means based on a comprehensive signal T obtained by calculating at least an output signal of a temperature setting device and an output signal of an inside air temperature sensor. , an air conditioner for a vehicle, characterized in that when the temperature of the evaporator reaches the lowest level, the magnitude of the overall signal T is changed to a value that sets the air mix door control means to the maximum cooling mode. Control method. (2) A comparison means compares the set signal T when the evaporator temperature reaches the lowest level with the above-mentioned total signal T, and when both signals become equal, the above-mentioned total signal T is changed by the set level. A method for controlling a vehicle air conditioner according to claim 1.