JPS5889414A - Controller for car air conditioner - Google Patents

Abstract

PURPOSE:To automatically prevent moisture from collecting on the front window glass by increasing the supply rate of air from the defrostor outlet when a difference between the interior air temperature and the set temperature is increased over a certain value. CONSTITUTION:Information of a car's room temperature 21, an open air temperature 22, a set temperature 23, a damper opening 24, a cooler's temperature 25 and a heater's temperature 25 is inputted into a digital computer 20a via an analogue I/O interface 10b. In conformity to the temperature control routine and the supply rate control routine, a computer 10a executes arithmetic operation on the information to control a solenoid valve 31 which shuts off the driving force from an engine EG to a cooling cycle CC, a solenoid valve 32 which shuts off the cooling water passage toward a heater 5, an interior and open air damper 2, a temperature controlling damper 7, and negative pressure actuators 33, 34 and 35a-35c for driving outlet dampers 8a-8c. The computer is programmed such that if a difference between the interior and the open air temperature is shown over a certain value, the damper 8c may be opened by the actuator 35c, whereby moisture collection on the glass may be automatically prevented.

Description

[Detailed Description of the Invention] The present invention makes it possible to automatically prevent fogging by increasing the volume of defrost air when the windshield of an automobile is in an environment where it becomes cloudy due to the difference in temperature between the inside and outside of the vehicle. The present invention relates to a car air conditioner control device.

In a car air conditioner, when the controllability of the cabin temperature is important, the lower the air volume, the better the passenger feeling is. It is usually designed to provide the minimum air volume. However, in a temperature environment where fogging occurs on the windshield in the scenery, the effect of eliminating fogging is small, so it is necessary to increase the air volume from the defrost outlet.

The present invention aims to prevent or eliminate the occurrence of fogging by detecting an environment where fogging easily occurs using a commonly used simple sensor. It is characterized by increasing the air volume from the outlet at least more than the minimum air volume in a stable state.

As is well known, fogging of a glass surface occurs when the humidity of the glass falls below the dew point, so it is possible to understand the temperature environment in which fogging occurs. Generally, when there is no sunlight, the temperature inside the glass is 1 of the interior temperature Tr and the outside air humidity 'I'am.
It can be roughly described by the following formula, ) f las m degree Tf F is Tp
= to 1-Tr-1- to 2-Tam (Kl, [2 is 1 x 0.6' according to our experiments.

2' = ro, b). Therefore, IL
Assuming that H=60% (60% under a general air-conditioned environment), the temperature environment in which fogging occurs is as follows, for example.

Therefore, (Tr-Tam) is approximately constant (approximately 20℃
). Therefore, the control device can process this value as a fixed value. This value may be modified depending on the absolute value of the internal temperature.

The present invention will be described below with reference to embodiments shown in the accompanying drawings.

In this embodiment, the present invention is applied to a generally known car air conditioner that mixes cold air and hot air. An outside air suction port 1a for introducing outside air and an inside air suction port 1b for circulating inside air are provided on the upstream side, and both suction ports are opened and closed by an inside and outside air damper 2. ventilation duct) 1
Inside, toward the downstream side, there is a blower motor 8, a refrigeration cycle/
Evaporator 4 forming part of L/CC, heater core 5 forming part of cooling water cycle yv HC of engine EG, and air passing through this heater core 5 and its bypass passage 6
Temperature control dampers (A/M dampers) 7 are arranged in order to adjust the ratio of air passing through the A/M dampers. A plurality of air outlets 1c, Id, and a defrost air outlet 1e are provided at the most downstream part of the ventilation duct (1) to blow out temperature-controlled air in the duct in each direction within the vehicle interior. are opened and closed by outlet dampers 8a, sb, and se.

In order to perform temperature control and various operation mode controls, the control device IO receives various information signals and executes processing based on a preset control program.
It electrically commands the operation of the air conditioning function section 8.

As a means for inputting various information signals to the control device IO, an analog voltage signal Tr' corresponding to one time inside the vehicle interior is used.
an outside temperature sensor 22 including a heat-sensitive resistor that produces an analog voltage signal T a m ' corresponding to the temperature outside the vehicle; a set temperature (set position);
A temperature setting device 23 including a potentiometer that generates an analog voltage signal Tset' corresponding to the opening degree of the temperature control damper 7, an opening seventer 24 including a potentiometer generating an analog voltage signal A r ' corresponding to the opening degree of the temperature control damper 7, and a downstream side of the cooler core Fuku. Cold air sensor 25° cooling water cycle including a heat-sensitive resistor that generates an analog voltage signal Ta' depending on the nearby air temperature
Analog voltage signal Tw according to the cooling water temperature in the pipe of C
A water temperature sensor 26 including a heat-sensitive resistor that generates an electric current, and a switch spring Iv11 that generates an on/off signal by operating a switch group for operation, stop, mode selection, etc. are provided.

In addition, as a means for operating functional elements by electrical commands from the control device IO, an electromagnetic clutch 81 that cuts off and connects the driving force from the engine EG to the refrigeration cycle cc, and a cooling to the heater core 5 in the heating cycle/L/HC are used. Solenoid valve 82 that opens and closes the water circulation path, internal and external air damper 2, and temperature control damper? , electromagnetic valve-controlled negative pressure actuators 88, 84, 35a, asb, and ssc are provided, which provide driving force for opening and closing the outlet dampers Ba, sb, and 8C using engine negative pressure. The display spring ztz1g displays the operating status of the air conditioner and the control device based on the output signal of the control device 1ito.

When the ignition switch 13 of the vehicle is turned on, the control device IO receives power supply from the on-vehicle patch 914 and becomes operational. As shown in FIG. 2, the control device 10& includes a digital computer (microcomputer) 10 that performs information processing based on a preset control program.
&, Faith! Input means 21, 112.23, 24, 25.2
An analog input interface 10b selectively converts the analog voltage signal from 6 into analog to digital and inputs it to the computer 10a, and converts the on/off signal of each switch from the switch spring μm1 into the computer 1
Digital input interface 100 for input to 0&
．． Functional elements 81 to 8 output from computer lOa
5, a power amplification circuit 1od for amplifying each operation command signal, an information processing clock generation circuit 1Of, an interface 10e for controlling the rotation speed of the blower motor 80, a constant voltage circuit, and an initialization circuit for starting the operation of the computer 10 & immediately after the ignition switch 180 is turned on. It is composed of circuits (none of which are shown).

FIG. 8 shows a control program for the digital computer 10a. This control program is a digital computer 1
At 0a, when the central processing unit (CPU) starts operating, it is read from the program memory (ROM) and the CPU
defines the operation of the control device 10 in relation to the input/output circuit of the
It regulates the operation of the entire electrical control system and the car air conditioner.

In addition, FIG. 8 shows the key points of the present invention, such as human power v-f (1), temperature adjustment routine (1), and air volume control μ.
mchin (1) is shown, and the rest are omitted because they can be referred to known techniques.

In the normal operation mode, the digital computer starts calculation processing from step 100 of the program. In step 101, various sensors 21, 22, 24,
25. In-vehicle air temperature Tr' and outdoor air temperature T that occur in 26
am', damper opening degree Ar', cooler temperature 'ra', heater temperature Tw', and target temperature Ts set' set by the temperature setter 28 are sequentially converted into binary code signals. Convert to digital data Tr, Tam,
Ar.

Ta, Tw, 'Tset are written to predetermined addresses in the built-in temporary storage memory (RAM). In the next step 102, based on each data inputted in step 101, the necessary hot cover to be blown out from the ventilation duct 1 is calculated as the value of the blown air temperature Tao, assuming that the blowing capacity of the blower motor 8 is constant in this embodiment. . This calculation is expressed by the following formula.

Tao=niset-Tset-Kam-Tam-[r
-Tr-1-C-(1) However, Tset...Target temperature, Tr...Indoor temperature.

T a m... outside temperature, C... constant, K s
e t −K r・Kam...Gain in the control system that increases the vehicle interior temperature T without being affected by the outside temperature Tam.
It has been determined in advance through experiments etc. to satisfy the condition that r matches the set temperature Tset.

In the next step 10B, the necessary blowing temperature Ta is determined.

is higher than the heater temperature Tw, and if it is higher (
If yes), in step 104, the damper opening comparison value AO is set to 100 (%). If the determination result in step 104 is no, the process advances to step 105. In this step 105, the required blowout temperature Tao is the cooler temperature Ta.
Determine if it is lower than If it is low, proceed to step 106 and compare the damper opening degrees [Ao is set to 0 (%). If the determination result is no, the process proceeds to step 107, where a damper opening comparison value 0 (%) is calculated and set using the following equation.

AO=MP+t1・・・・・・・・・・・・(2)(2
) calculation is the required blowing air temperature Ta.

In the case of obtaining , the damper opening degree (AO) is calculated according to the cooler temperature Ta and the heater temperature TW.

The result of calculation using this formula (2) or step 10
The comparison value AO (9) of the damper opening set by 4.106 is the damper opening amount to be adjusted (adjustment l).
it>. And step 108
~11g shows the process of converging the damper opening degree Ar to the comparison value AO in order to obtain the blown air temperature r[, o.

First, steps 108 and 110 are for determining whether the damper opening degree Ar read in step 101 matches the range of damper opening degree AO±aO for obtaining the blown air temperature Tao, where ao is the damper opening degree Ar read in step 101. This value is for adding a certain range to the adjustment position Ao to provide a so-called dead zone in order to stabilize the opening control.

Then, in step 108, the actual damper opening degree Ar
If it is determined that is larger, the process proceeds to step 109, where the negative pressure of the negative pressure actuator 84 acting on the air mix damper 7 is relaxed, and the damper opening degree Ar is decreased. If it is determined in step 110 that the actual damper opening degree Ar is smaller, the process proceeds to step 111 and the negative pressure of the negative pressure actuator 84 acting on the damper 7 is increased. Damper opening degree Ar
enters the adjustment range Ao-1-ao, step 112
At (10), a command to stop the operating position of the negative pressure actuator 84 is issued.

The role of the temperature adjustment routine (1) explained so far is to obtain the required outlet air temperature in response to changes in input control conditions and insufficient capacity of the heat exchanger 4.5, and to maintain a stable temperature inside the vehicle. It is.

This means that when the cold air temperature Ta fluctuates as a result of turning on and off the compressor 81 in some way, the vehicle interior temperature T
This has the effect of suppressing the deviation of r from the target temperature Tset.

Next, in the air volume control routine (■), in step 118, the fan switch mode from the switch panel 11 is determined, and if it is automatic mode, in step 114, the air volume W o u
Calculate t. This calculation is performed using a certain formula. On the other hand, if it is manual (fixed) mode, step 115
Calculate the relevant air volume. When the above calculations are completed, the process moves to step 116, where the vehicle interior temperature Tr and the outside air (fi
The difference in Tam is determined, and if the difference is larger than a constant value ΔT, in step 117, the step 114°1
The air volume increase ΔW is added to the calculated value Wout obtained in step 16, the defrost damper 80 is opened in step 118, and W o +1 t is outputted to the interface lOe in step 119. If the difference is less than ΔT in step 116, jump 117°118,
, 115 and outputs Wout. In other words, on the air volume side (al w-chin), by increasing the air volume when the outside temperature is much lower than the inside temperature,
Eliminate Rio.

The above embodiment is an example in which a microcomputer is used for a vehicle interior temperature control air conditioner generally called an automatic air conditioner. It is clear that any type of air conditioner can be used, and it does not have to be an air conditioner that constantly controls the room temperature.

For example, a manual type air conditioner, which is generally called a manual air conditioner, is equipped with the sensor, and a circuit is installed to determine the difference between the detected values of the sensor. Also good. .

As described above, the present invention can easily ensure safe visibility.

[Brief explanation of the drawing]

FIG. 1 is a block diagram of a car air conditioner control device according to an embodiment of the present invention, FIG. 2 is a block diagram of its electrical system, and FIG. 8 is a flowchart showing a control program of a control computer. 16...Defrost discharge port, 3...Prower motor. lO...Control device, 21...Inside temperature sensor, 22°
°・Outside temperature sensor. Representative patent attorney Takashi Okabe (18)

Claims (1)

[Claims] A sensor that detects at least the inside air temperature and outside air temperature, and a duct that contains a blower motor and a heat exchanger and has a defrost outlet, detects when the temperature difference between the inside air temperature and the set temperature is larger than a predetermined value. and an electric control means for increasing the amount of air blown from the defrost outlet.