JPS6241131B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an air conditioner for an automobile including a cooling mechanism whose driving source is an automobile power engine (hereinafter referred to as engine).

Generally, this type of automotive air conditioner has a cooling mechanism including a refrigerant compressor coupled to an engine via an electromagnetic clutch. When the air conditioner is in operation (mainly when used for cooling or dehumidification purposes), the cooling mechanism is connected to the engine by an electromagnetic clutch to put the cooling mechanism into operation. In addition, the electromagnetic clutch is shut off when the engine load is large, such as when driving on a slope with a large slope, when attempting to accelerate suddenly, or when the engine coolant temperature rises above a predetermined value (overheating). By stopping the cooling mechanism, it is necessary to reduce the load on the engine, maintain driving performance, and prevent overheating. However, there is a problem in that the desired cooling effect of stopping the cooling mechanism cannot be obtained and the temperature inside the vehicle increases.

SUMMARY OF THE INVENTION In view of the above problems, it is an object of the present invention to provide a device that can prevent the temperature inside a vehicle from increasing as much as possible even when the cooling mechanism is stopped.

In order to achieve this object, the present invention arranges a cooling heat exchanger 4 in a ventilation duct 1 having an inside air suction port 1b and an outside air suction port 1a, as shown in FIG.
Cooling mechanism to operate this cooling heat exchanger
A joint 31 that connects the CC to the motor vehicle engine in an intermittent manner, and the inside air suction port 1b and the outside air suction port 1.
In an automobile air conditioner equipped with a switching device 2, 33 that selects and switches between
and an outside temperature sensor 22 that detects the outside air temperature outside the vehicle interior.
and determines that the motor vehicle power engine EC is in a high load state, and connects the cooling mechanism CC to the joint 31.
a first control means M1 that generates an electric signal to cut off the motor from the vehicle power engine EG; and when the first control means M1 determines the high load state, the inside temperature sensor 21 and the outside temperature sensor a second control means M2 that determines whichever is lower among the temperatures detected at 22 and generates an electric signal that causes the switching devices 2 and 33 to introduce this lower temperature air into the ventilation duct 1; Adopt technical means of equipping.

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 known automobile air conditioner using a cold air/warm air mixing method. An outside air suction port 1a for introducing outside air and an inside air suction port 1b for circulating inside air are provided, and both suction ports are opened and closed by an inside and outside air damper 2. In the ventilation duct 1, toward the downstream side, there are a blower motor 3, an evaporator 4 forming a part of the cooling mechanism CC, a heater core 5 forming a part of the cooling water cycle HC of the engine EG, and the air passing through the heater core 5. Temperature control dampers (A/M dampers) 7 are arranged in order to adjust the ratio to the air passing through the bypass passage 6. At the most downstream part of the ventilation duct 1, upper and lower air outlets 1c and 1d are provided to blow out the temperature-controlled air in the duct to the upper and lower parts of the vehicle interior, and both air outlets are connected to air outlet dampers. It is opened and closed by 8.

In order to perform temperature control and various operation mode controls, the control device 10 receives various information signals, executes processing based on a preset control program, and operates the air conditioning function sections 1 to 8 described above. Configured to command electrically.

As a means for inputting various information signals to the control device 10, an inside temperature sensor 21 including a heat-sensitive resistor that generates an analog voltage signal Tr' corresponding to the temperature inside the vehicle interior, and an analog voltage signal corresponding to the temperature outside the vehicle interior.
an outside temperature sensor 22 including a heat-sensitive resistor that produces Ta';
Analog voltage signal according to set temperature (set position)
Analog voltage signal corresponding to the opening degree of temperature setting device 23 and temperature control damper 7 including variable resistance that generates Ts′
An opening sensor 24 that includes a potentiometer that generates Ar', a cold air sensor 25 that includes a heat-sensitive resistor that generates an analog voltage signal Tc' that corresponds to the air temperature near the downstream side of the cooler core 4, and cooling water in the piping of the cooling water cycle HC. a water temperature sensor 26 including a heat-sensitive resistor that generates an analog voltage signal Tw' corresponding to the temperature; an outlet temperature sensor 27 including a heat-sensitive resistor that generates an analog voltage signal Tao' corresponding to the temperature of the outlet air at the upstream portion of the outlet damper 8; The throttle opening sensor 28 includes a heat-sensitive resistor that generates an analog voltage signal θ' corresponding to the opening of the engine speed regulating throttle valve TH, and generates on/off signals by operating a group of switches such as operation, stop, and dehumidification mode selection. A switch panel 11 is provided.

In addition, the engine EG
An electromagnetic clutch 31 disconnects and connects the driving force from the cooling cycle CC to the cooling cycle CC, and an electromagnetic valve 3 opens and closes the cooling water circulation path to the heater core 5 in the heating cycle HC.
2, and an inside/outside air damper 2, a temperature control damper 7,
Solenoid valve-controlled negative pressure actuators 33, 34, which provide driving force for opening and closing the outlet damper 8 using engine negative pressure;
35 are provided. The display panel 12 is the control device 1
The operating status of the air conditioner and the control device is displayed by the output signal of 0.

As shown in FIG. 2, the control device 10 includes a CPU,
A digital computer (microcomputer) 10a that has ROM, RAM, I/O port with latch, timing generation circuit, etc. and performs information processing based on a preset control program, signal input means 21, 22, 23, 24, 25, 26, 2
An analog input interface 10 that selectively converts analog voltage signals from 7 and 28 into analog-to-digital conversion and inputs them to the computer 10a.
b. A digital input interface 10c that formats the on/off signals of each switch from the switch panel 11 and inputs them to the computer 10a; and functional elements 31 to 3 output from the computer 10a.
A power amplification circuit 10 that amplifies the operation command signal of No. 5.
d, blower information processing clock generation circuit 10f;
Interface 10 for controlling the rotational speed of the motor 3
e, a constant voltage circuit, and an initialization circuit (none of which are shown) that starts the operation of the computer 10a immediately after the ignition switch 13 is turned on.

As shown in FIG. 3, the rotational speed control interface 10e includes a latch circuit 41 that latches a binary signal 41a representing rotational speed data in synchronization with a timing signal 41b, and a latch circuit 41 that latches a binary signal 41a representing rotational speed data in synchronization with a timing signal 41b. Digital-to-analog conversion circuit (A/D conversion circuit) 4 that converts into a voltage signal 42a
2, and a triangular wave voltage signal 4 with a constant frequency and constant amplitude.
3a, and both voltage signals 42.
a, 43a to obtain a pulse train 44a with a constant frequency and a duty ratio proportional to the magnitude of the analog voltage signal 42a, and an amplifier circuit 45 which amplifies this pulse train 44a and applies it to the blower motor 3. Consists of blower motor 3
The rotation speed is controlled by controlling the duty ratio of the energizing current.

The control device 10 is controlled by the computer 10a.
Through arithmetic processing based on a control program stored in the ROM, the temperature of the air blown into the vehicle interior from the air conditioning function section and the opening degree of the air mix damper 7 are commanded and controlled as described later. Further, although detailed explanation will not be given, switching control of the inside/outside air switching damper 2 and the outlet switching damper 8, display control of the inside air temperature on the display panel 12, etc. are also performed.

FIG. 4 shows the flow of the control program of the computer 10a, and the apparatus is operated according to this control program which is repeated at a cycle of several tens of milliseconds.

When the ignition switch 13 is turned on, power supply to the electrical control system shown in FIG. 2 is started, and the computer 10a sets the arithmetic processing to an initial state in step 101 in response to a timing signal from an initialization circuit (not shown). At this time, data indicating the rotational speed of 0 is given to the interface 10e such that the rotational speed of the blower motor 3 is 0. Next, in a data input step 102, the on states of the various switches on the switch panel 11 are inputted via the interface 10c and stored in the allocated address of the RAM. Further, the signal input means 21
Analog voltage signals Tr', Ta', Ts',
Tc′, Tw′.Ar′, Tao′, θ′ as interface 1
digital data Tr, respectively via 0e.
Store it at a specified location in RAM as Tam, Ts, Tc, Tn, Ar, Ta, and θ. Note that the analog voltage signal Ar′ indicating the opening degree of the A/M damper is digital data Ar
When the data is converted into data and stored in the RAM, it is converted into data indicating the degree of opening as a percentage using a predetermined functional formula.

Next, in a judgment step 103, among the data input in step 102, the state of the operation switch of the air conditioner in the switch panel 11 is read out from the RAM and is determined whether it is turned on (ON) (YES) or not (NO).
If YES, start step 1
At step 04, an operation command (energization) is given to the solenoid valve 32 via the amplifier circuit 10'd, and the heat exchanger (cooler core 3, heater core 5) is put into operation.

Next, switching between the outside air suction port 1a and the inside air suction port 1b and whether the cooling mechanism is activated or not are determined, and the internal and external air damper 2 is opened/closed and the electromagnetic clutch 31 is activated.
A process 105 for instructing to turn on and de-energize, a process 106 for determining the blowing air volume and instructing the rotational speed of the blower motor 3, and an opening degree of the A/M damper 7 necessary to maintain the vehicle interior temperature at the set temperature. The process 107 determines whether the blown air should be blown upward into the vehicle interior (mainly the upper body of the occupant) or downward into the vehicle interior (mainly the lower body of the occupant). Process 1 for commanding the opening and closing of the air outlet damper 8
08 in order, and then data input step 10 again.
Step 2 and repeat the above process. When the operation switch on the switch panel 11 is opened, the process proceeds from the determination step 103 to the stop step 109, where the electromagnetic clutch 31 and the electromagnetic valve 32 are deenergized via the amplifier circuit 10d, and the blower motor 3 is rotated via the interface 10e. A speed of 0 is commanded. Further, a deenergization command is also given to the negative pressure actuators 33 to 35, and the dampers 2, 7, and 8 each stop at a mechanically determined position.

Details of the above processes 105 to 108 are shown in FIG. In FIG. 5, it is determined in step 110 whether the outside temperature Ta is 5° or more lower than the set temperature Ts (YES) or not (NO).
In step 11, it is determined whether dehumidification is required.
That is, the data of the dehumidification switch in the switch panel 11 is read from the RAM, and if the dehumidification switch is turned on, the process goes to step 116, and if not, the process goes to step 112, where the outside air intake port 1 is turned on.
Negative pressure actuator 33 is energized to open a. In addition,
When the control program is repeatedly executed, this energizing command is repeatedly output, but the negative pressure actuator 33 can be energized and read by the latching action of the output port of the computer 10a until the deenergizing command is output. If it is determined in step 111 that dehumidification is not necessary, that is, the dehumidification switch is not turned on, the cooling mechanism is stopped in step 114.

In steps 116 and 117, the engine load condition is determined. First, in step 116, it is checked whether the throttle valve opening θ is greater than or equal to a set value θs set near the maximum opening (YES) or not (NO), and if YES, the process proceeds to step 118. In addition, when NO, the engine coolant temperature is
Tw is greater than or equal to the set value Tws determined in response to the overheating state. (YES) or not (NO) is checked, and if YES, proceed to step 118. That is, when it is determined that it is necessary to reduce the engine load, step 118 is reached.

In step 118, the vehicle interior temperature (inside temperature)
Tr and the vehicle outside temperature (outside temperature) Ta are compared, and the inside temperature Tr is lower than the outside temperature Ta. (YES), the negative pressure actuator 33 is deenergized in step 119 to open the inside air suction port 1b, and when the outside temperature Ta is lower than the inside temperature Tr (NO), the outside air suction port 1a is opened in step 120. The negative pressure actuator 33 is energized accordingly. Then, after steps 119 and 120, step 11
4 and commands the cooling mechanism to stop.

If it is determined in steps 116 and 117 that there is no need to reduce the engine load, the process proceeds to step 121, where the internal temperature Tr is 5°C lower than the set temperature Ts.
It is determined whether the pressure is higher than or equal to (YES) or not (NO), and if YES, the negative pressure actuator 33 is deenergized in step 122 to open the inside air suction port 1b.
If NO, go to step 123 to open the outside air inlet 1a.
energizes the negative pressure actuator 33 to open; In other words,
When the inside temperature Tr is gradually higher than the set temperature Ts, for example, when it is higher than 5 degrees Celsius, inside air circulation is activated to rapidly lower the cabin temperature, and the inside temperature Tr and the set value are
When the difference from Ts is within 5°C, fresh air is sent into the cabin as outside air. In step 113, it is determined whether the cooling air temperature Tc after passing through the cooler core 4 is lower (YES) than the set value Tcs (for example, 1°C) (NO), and if YES, the stop step 1 is performed.
At step 14, the electromagnetic clutch 31 is shut off to prevent overcooling of the cooler core. If NO, step 11
At step 5, the electromagnetic clutch 31 is brought into the connected state.

Next, in step 124, the inside temperature Tr and the set temperature Ts are determined.
The difference ΔT is calculated, and then in step 125, the basic air volume W _B corresponding to the difference ΔT is read from the ROM. This basic air volume W _B is stored in a matrix format in a predetermined range of ROM, and is determined, for example, as shown in Fig. 6, and is set so that the smaller the difference △T, the smaller the air volume. The data W _B is read from the ROM using the address corresponding to the address. Furthermore, in step 126, the increased air volume Wa corresponding to the outside temperature Tam is similarly read out from the ROM. This increased air volume Wa is determined, for example, as shown in FIG. 6, and the higher the outside temperature Ta, the higher the increased air volume Wa. Air volume data W read out in steps 125 and 126
By adding _B and Wa in step 127,
Determine the airflow volume W of the air conditioner. Step 12
At 8, this blown air volume W is given to the interface 10e, and the blower motor 3 rotates at a corresponding rotational speed. As the control program is repeated, the air volume data W is repeatedly relatched to the interface 10e, but since the latching time is extremely short, the rotational speed of the blower motor 3 does not fluctuate.

In steps 129, 130, and 131, the amount of air blown out from the ventilation duct 1 Tbo necessary to maintain the vehicle interior temperature at the set value Ts is calculated. First, in steps 129 and 130, the internal temperature is
The required amount of heat Q to be released into the passenger compartment is calculated according to Tr, set temperature Ts, and outside temperature Ta. however,
Ks, Ka, Kf, C are constants when the blowout air volume is a constant value Wo, and Tb ₁ is the assumed air volume Wo.
is the required blowing air temperature at Subsequently, in step 131, the blowing air temperature Tb ₁ necessary to obtain the required amount of heat Q at the determined air volume W is determined.
Calculate. Here, Kg is a constant determined by the specifications of the air conditioner.

Next, the A/M damper 7 is used to obtain the discharge air temperature _Tb1 calculated in steps 132 to 136.
The opening degree Ao is determined by taking into consideration the heat exchange capacity of the heat exchangers 4 and 5. First, the outlet air temperature Tb ₁ calculated in determination step 132 is equal to the engine cooling water temperature Tw.
It is determined whether it is higher (YES) or not (NO),
If YES, the opening degree Ao of the A/M damper 7 is set to 100 (%, fully open) in step 133. NO.
In this case, in judgment step 134, the outlet air temperature Tb ₁
It is determined whether (YES) or not (NO) is lower than the cooling temperature Tc of the downstream part of the Tara core. If (YES), the damper opening degree Ao is set to 0 in step 135.
(%, fully closed). If NO, in step 136, the damper opening Ao is calculated using the calculation formula shown in the figure.
A value expressed as a percentage is calculated.

Next, set the actual damper opening degree Ar in step 13.
Steps 134 to 138 are processed so as to substantially match the value Ao set in step 3, 135 or 136. In steps 134 and 136, the magnitude relationship between the required damper opening Ao±a (a is the deviation value for providing hysteresis) and the actual damper opening Ar is determined, and when Ar≧(Ao+a), step 135 in the direction of closing the A/M damper 7 (first
The first electromagnetic valve (not shown) in the negative pressure actuator 34 is energized to drive in the direction of the broken line arrow in the figure. Ar≧(Ao
-a), in step 137 the A/M
A negative pressure actuator 34 is used to drive the damper 7 in the opening direction.
energizes a second solenoid valve (not shown) inside. In addition,
Although not particularly shown, when one of the first and second solenoid valves is energized, a deenergization command is output to the other. (Ao＋
When a)>Ar>(Ao-a), both solenoid valves are deenergized. When steps 134 to 138 are repeated, if the value of Ao is constant, the actual damper opening
Ar is eventually statically determined in the range of (Ao+a)>Ar>(Ao-a).

Next, steps 139 to 142 are performed to switch the opening and closing of the outlet damper 8. Judgment step 1
At 39, the measured outlet air temperature Tao was 30℃
It is determined whether the above is true (YES) or not (NO),
If YES, in step 140, the negative pressure actuator 3 is activated to open the lower outlet 1d by the outlet damper 8.
Deactivate 5. If NO, proceed to step 141 and the outlet air temperature Tao is below 28℃ (YES)
It is determined whether or not (NO), and if YES, the negative pressure actuator 35 is deenergized in step 142 to open the upper air outlet 1c. When NO, no change of air outlet is commanded.

The computer 1 shown in FIGS. 4 and 5 above
Although the flow of the control program 0a has been described, the process in which the computer 10a repeatedly executes this control program by turning on the operation switch in the switch panel 11 to control the air conditioner will be summarized below.

(1) Processing 105 (steps 110 to 123 in FIG. 5) regarding opening/closing of the internal/external air damper 2 and engagement/deenergization of the electromagnetic clutch 31. Steps 110, 111, 113, and 11 determine whether the electromagnetic clutch 31 is energized to operate the cooling mechanism or deenergized to stop it.
6,117, and the conditions for deactivation are listed below.

(a) The outside temperature Ta is 5°C or more lower than the set value Ts (110 → YES). When the dehumidification switch is not turned on (111→NO).

(b) When the throttle valve opening θ is greater than the set value (116 → YES) or the cooling water temperature TW
is greater than the set value (117→YES).

(c) The cold temperature Tc is below the setting (113→
YES) When.

Under other conditions, the electromagnetic clutch 31 is energized. Steps 110, 116, 117 determine whether to open the inside air intake port or the outside air intake port.
118 and 121, and the conditions for opening the inside air suction port are listed below.

(d) When the outside temperature Ta is 5°C or more lower than the set temperature Ts (110 → YES) and the dehumidification switch is not turned on (112 → NO).

(e) Conditions for energizing the electromagnetic clutch (110→
NO, or 112 → YES), and the throttle valve opening θ is greater than or equal to the set value (116
→YES) or the cooling water temperature Tw is higher than the set value (117→YES), and
The outside temperature Ta is greater than or equal to the inside temperature Tr (118→
YES) When.

(f) Conditions for normally energizing the electromagnetic clutch 31 (110→NO or 112→YES, 1
16→NO, 117→NO), when the internal temperature Tr is higher than the set temperature Ts by 5℃ (121→NO).

Under other conditions, the outside air intake port is opened.

What is particularly noteworthy about the relationship between the opening and closing of the internal and external air damper 2 and the engagement and deenergization of the electromagnetic clutch 31 is that the throttle valve opening θ is greater than the set value (116→
YES) or the cooling water temperature Tw is higher than the set value (117→YES), that is, when the engine load is increasing, the electromagnetic clutch 31
At the same time, the internal temperature is
Tr is the point at which the opening and closing of the inside and outside air damper 2 is determined in order to introduce air having a lower temperature, whichever is the outside temperature Ta.

(2) Process 106 regarding control of the amount of air blown out (steps 124 to 128 in FIG. 5). Depending on the difference △T between the inside temperature Tr and the set temperature Ts, the base air volume W _B is determined as shown in Figure 6, and as the outside temperature Ta increases, the air volume increases as shown in Figure 7.
Wa is added, and the blowout air volume W is determined based on the relationship between the inside temperature, the set temperature, and the outside temperature. In other words, when the inside temperature Tr approaches the set temperature Ta, the air volume W is reduced, and the outside temperature
The higher Ta is, the more air volume W is increased.

(3) Processing 107 regarding control of blowout temperature (steps 129 to 138 in FIG. 5). At the air volume _W , the outlet air temperature Tb ₁ to bring the internal temperature Tr closer to the set temperature Ts is calculated, and the cooling water temperature Tw,
Opening degree Ao of A/M damper 7 considering cold temperature Tc
is determined by calculation, and the opening degree of the A/M damper 7 is adjusted according to a comparison between this calculated value Ao and the actual opening degree Ar of the A/M damper 7.

(4) Process 108 regarding control of blowing direction (steps 139 to 142 in FIG. 5). Outlet air temperature Tao
When is greater than or equal to the set value, the upper outlet 1c is opened, and when it is greater than the set value, the lower outlet 1d is opened.

As described above, the air conditioner is controlled according to the control program of the computer 10a. When a condition requiring a reduction in engine load occurs, the electromagnetic clutch 31 is disconnected, and at the same time, the opening/closing of the inside/outside air damper 2 is determined so as to introduce air at the lower of the inside and outside temperatures. This makes it possible to supply air as low as possible to the cooler core 4, thereby preventing the temperature in the vehicle interior from increasing away from the target value in the operating state of cooling the vehicle interior.

In the above-described embodiment, in the determination at step 118, the internal air intake and the external air intake are switched based on a simple comparison between the internal temperature Tr and the external temperature Ta. In order to stabilize switching, a hysteresis characteristic may be set to provide two comparison points.

In addition, when the engine load is detected by the throttle opening sensor 28, in order to prevent malfunction of the device due to temporary changes in the throttle, the throttle opening θ is continuously adjusted to a set value θs for a certain period of time or more.
The program may be corrected to determine that the

As described above, in the present invention, when it is determined that the automobile engine is in a high load state, regardless of the level of the outside air temperature and the inside air temperature, the driving force is transmitted from the automobile engine to the cooling mechanism. Since this is reliably shut off, it is possible to reliably prevent failures such as overheating.

Furthermore, since the lowest possible air temperature is supplied to the cooling heat exchanger when the cooling mechanism is stopped, there is an excellent effect that the increase in the temperature inside the vehicle due to the stopping of the cooling mechanism can be suppressed to a small level.

[Brief explanation of the drawing]

FIG. 1 is an overall configuration diagram showing one embodiment of the device of the present invention, FIG. 2 is a block diagram showing the electrical control system of the device shown in FIG. 1, and FIG. 3 is a detailed diagram of the interface 10e in FIG. FIG. 4 is a flowchart showing an overview of the control program of the computer 10a in FIG. 2, FIG. 5 is a block diagram showing details of main parts of the control program shown in FIG. 4, FIG. FIG. 7 is a characteristic diagram for explaining the air volume characteristics determined by the control program shown in FIG. 5, and FIG. 8 is a block diagram showing the configuration of the present invention. DESCRIPTION OF SYMBOLS 1... Ventilation duct, 1a... Outside air suction port, 1b... Inside air suction port, 2... Damper for switching inside and outside air, 4... Cooling heat exchanger, 10... Control device forming control means, 21
...Inside temperature sensor that detects the temperature inside the vehicle, 22...Outside temperature sensor that detects the temperature outside the vehicle, 26...Engine coolant temperature sensor, 28...Throttle opening sensor, 31...Joint (electromagnetic clutch), 33...Negative pressure operation vessel.

Claims (1)

[Claims] 1. A cooling heat exchanger is disposed in a ventilation duct having an inside air suction port and an outside air suction port, and a cooling mechanism for operating this cooling heat exchanger can be freely connected to an automobile power engine. An air conditioner for an automobile includes a coupling coupled to the inside air intake port and a switching device for selectively switching between the inside air intake port and the outside air intake port, the air conditioner comprising: an inside temperature sensor that detects the air temperature inside the vehicle interior; and an outside air temperature sensor outside the vehicle interior. a first control means that determines that the motor vehicle power engine is in a high load state and generates an electric signal that causes the joint to disconnect the cooling mechanism from the motor vehicle power engine; When the first control means determines the high load state, it determines whichever is lower among the temperatures detected by the inside temperature sensor and the outside temperature sensor, and directs this lower temperature air to the switching device. and second control means for generating an electric signal to be introduced into the ventilation duct.