JPH0448643B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a vehicle air conditioner incorporating control by a microcomputer.

Conventionally, this type of device includes a ventilation duct that introduces air from inside or outside the vehicle interior and blows this air out to a suitable location within the vehicle interior, and a device installed in the ventilation duct so as to occupy the entire cross section of one of the ventilation ducts. a cooling heat exchanger that lowers the temperature of flowing air; and a cooling heat exchanger that is located downstream of the cooling heat exchanger in the air flow and is provided in the ventilation duct so as to occupy a part of one cross section of the ventilation duct, A heating heat exchanger increases the temperature of the circulating air, and the air flowing through the ventilation duct is divided into air passing through the heating heat exchanger and air bypassing the heating heat exchanger. and an air mix damper that adjusts the distribution ratio.
Furthermore, a temperature setting device that is arbitrarily set to a desired temperature and generates a signal representing the set temperature, an outside air temperature sensor that detects the outside air temperature and generates a signal representing the detected temperature, and a temperature sensor that detects the interior temperature of the vehicle; It is equipped with a vehicle interior temperature sensor that generates a signal representing the detected temperature, and an after-cooling temperature sensor that detects the air temperature downstream from the cooling heat exchanger through the air flow and generates a signal representing the detected temperature. By computer,
Based on the signals from the temperature setting device and each sensor, it calculates the target outlet temperature of the ventilation duct necessary to maintain the vehicle interior temperature at the set temperature, and also calculates the air temperature downstream from the cooling heat exchanger. The distribution ratio of the air mix damper required to raise the temperature to the target blowout temperature was calculated, and the actuator was then used to drive the air mix damper to achieve the calculated distribution ratio. .

In addition, when the outside air temperature is sufficiently lower than the target air temperature, the target air temperature can be obtained without operating the cooling heat exchanger. The supply of refrigerant to the heat exchanger had been stopped.

However, when controlling the temperature by selectively supplying refrigerant to the cooling heat exchanger, there is a delay in response due to the heat capacity of the cooling temperature sensor.
Immediately after refrigerant supply is started or stopped, the temperature detected by the after-cooling temperature sensor may be higher or lower than the actual temperature, and as described above, the temperature detected by the after-cooling temperature sensor may be higher or lower than the actual temperature. With conventional devices that operate air mix dampers based on signals from the vehicle, there is a problem in that the outlet temperature of the ventilation duct is either too low or too high than the target outlet temperature, impairing the comfort of the occupants, even if only temporarily. .

In view of such conventional problems, an object of the present invention is to accurately detect the temperature after cooling and control the temperature even immediately after the supply of refrigerant to the cooling heat exchanger is started or stopped. Therefore, the purpose is to prevent the blowing temperature from becoming too low or too high even immediately after the supply of refrigerant is started or stopped.

The first configuration of the present invention to achieve this purpose is as follows.
This will be explained using figures.

The ventilation duct 1 introduces air from inside the vehicle interior or outside the vehicle interior, and blows this air out to appropriate locations within the vehicle interior. In this ventilation duct 1, a cooling heat exchanger 1 is installed.
5 and a heating heat exchanger 20 are inserted, and the cooling heat exchanger 15 is provided so as to occupy the entire surface of one cross section of the ventilation duct 1, and reduces the temperature of the circulating air and also increases the heating heat exchanger 15. The exchanger 20 is located downstream of the cooling heat exchanger 15 in the air flow and is provided so as to occupy a part of one cross section of the ventilation duct 1, and increases the temperature of the flowing air.

Furthermore, an air mix damper 21 is provided in the ventilation duct 1, and the air mix damper 21 is
Air flowing through the ventilation duct 1 is divided into air flowing through a heating heat exchanger 20 and air flowing bypassing the heating heat exchanger 20, and the distribution ratio is adjusted.

In addition, a temperature setting device 25, an outside air temperature sensor 26, a vehicle interior temperature sensor 27, and an after-cooling temperature sensor 29 are provided, and the temperature setting device 25 is arbitrarily set to a desired temperature and generates a signal representing the set temperature. do. Further, each temperature sensor detects the outside air temperature, the vehicle interior temperature, and the post-cooling temperature downstream of the cooling heat exchanger 15, respectively, and generates a signal representing each detected temperature.

The target outlet temperature calculation means receives signals from the temperature setting device 25, the outside air temperature sensor 26, and the vehicle interior temperature sensor, and calculates the target outlet temperature of the ventilation duct 1 necessary to maintain the vehicle interior temperature at the set temperature. calculate.

The refrigerant supply control means receives signals from the outside air temperature sensor 26 and the target blowout temperature calculation means, compares the outside air temperature with the target blowout temperature, and determines that the outside air temperature is lower than the target blowout temperature and that the difference is a predetermined value. In the above cases, a signal to stop the supply of refrigerant to the cooling heat exchanger 15 is generated, and in other cases, a signal to supply the refrigerant to the cooling heat exchanger 15 is generated.

The refrigerant supply device 40 intermittents the supply of refrigerant to the cooling heat exchanger 15 in accordance with a signal from the refrigerant supply control means.

The timer receives a signal from the refrigerant supply control means and measures the time since the refrigerant supply is started or stopped.

The after-cooling temperature calculation means is the after-cooling temperature sensor 29.
and a signal from the timing means, and in order to correct the response delay of the post-cooling temperature sensor 29, the actual Find the temperature after cooling.

The distribution ratio calculation means receives signals from the post-cooling temperature calculation means and the target blowout temperature calculation means, and operates an air mix damper necessary to raise the air temperature downstream of the cooling heat exchanger 15 to the target blowout temperature. The distribution ratio of 21 is calculated.

The actuator 23 receives a signal from the distribution ratio calculating means and drives the air mix damper so as to achieve the calculated distribution ratio.

According to the present invention described above, since the temperature detected by the after-cooling temperature sensor is corrected to detect the accurate after-cooling temperature and control is performed based on this,
It is possible to prevent the blowout temperature from being too low or too high due to a sensor response delay, and comfortable air conditioning can be achieved.

Embodiments of the present invention will be described below with reference to the drawings.

FIG. 2 is a schematic configuration diagram of one embodiment, where 1 is a ventilation duct, and the ventilation duct 1 is provided with an interior air intake 2 and an exterior air intake 3 at one end thereof. , one of these is selectively opened and the other is closed by an inside/outside air switching damper 4. Further, the ventilation duct 1 has a heater outlet 6 and a vent outlet 7 at the other end. Normally, the heater outlet 6 is provided below the instrument panel and is configured to blow air mainly toward the feet of the passenger seated in the seat, while the vent outlet 7 is provided at the front of the instrument panel. It is configured to blow air primarily toward the upper body of the occupant seated on the seat. Heater outlet 6 and vent outlet 7
In this embodiment, the damper 8 is selectively opened and closed by one switching damper 8 driven by the air outlet switching actuator 9. Further, the ventilation duct 1 has a defroster outlet 10 at the other end.
The defroster outlet 10 is selectively opened and closed by a damper 11 driven by an actuator 9'.

An electric motor 12 is located near the one end of the ventilation duct 1.
A blower fan 13 is provided, which is rotationally driven by a blower. The rotational speed of the electric motor 12 is controlled by a blower fan control device 14 configured with a variable resistor, a pulse control device, or the like.

Further, in the ventilation duct 1 on the downstream side from the arrangement position of the ventilation fan 13 in terms of the air flow, there is a device that crosses all the airflow flowing through the ventilation duct 1, that is, the entire surface of one cross section of the ventilation duct 1. An evaporator 15, which is a cooling heat exchanger, is provided so as to occupy the entire space. The evaporator 15 includes a compressor (refrigerant supply device) 40, a condenser 41,
Together with the expansion valve 42 and the expansion valve 42, it constitutes a refrigeration cycle, to which refrigerant is supplied.

Further, an air mix type temperature control mechanism 19 is provided in the ventilation duct 1 on the downstream side of the location where the evaporator 15 is disposed. A heater core 20 is provided as a heating heat exchanger, and the airflow flowing in the ventilation duct 1 is divided into a first airflow flowing through the heater core 20 and a second airflow flowing bypassing the heater core 20. and an air mix damper 21 driven by an actuator 23 to separate the blown air by adjusting the opening of the air mix damper 21 and adjusting the distribution ratio of the first and second air flows. It is designed to regulate the temperature of the
Furthermore, engine cooling water (not shown) is supplied to the heater core 20 in a circulating manner through a cooling water conduit 22.

Here, when the air mix damper 21 is located at the position shown by the solid line in FIG.
The blowout temperature increases by flowing through the
On the other hand, when the damper 21 is in the position shown by the two-dot chain line in FIG.
All airflow flowing through the heater core 20 bypasses the heater core 20, resulting in a lower blowout temperature.

In addition, the control circuit 24 including a microcomputer includes a temperature setting device 25 that is operated according to the will of the driver, an outside air temperature sensor 26,
Vehicle interior temperature sensor 27, solar radiation sensor 28, and evaporator back temperature sensor (cooling back temperature sensor)
29 detection outputs are input, and based on these detection outputs, the air outlet switching actuator 9, the actuator 23, and the blower fan speed control device 1 are inputted.
The control signal is output to each of the four terminals.

The control circuit 24 uses an outside air temperature sensor 26 to control the vehicle interior temperature to a target temperature near the set temperature.
The target air temperature Tao is calculated based on the outside air temperature detected by the controller, the vehicle interior temperature detected by the vehicle interior temperature sensor 27, the amount of solar radiation detected by the solar radiation sensor 28, and the set temperature set by the temperature setting device 25.

Tao＝K ₁ Tset−K ₂ Tam−K ₃ Tr−k ₄ St＋C…
...(1) Tset: Set temperature Tam: Outside temperature Tr: Vehicle interior temperature St: Solar radiation K ₁ , K ₂ , K ₃ , K ₄ , C are constants Next, the control circuit 24 sets the temperature to the above target air temperature. The mixing ratio (distribution ratio) of the first airflow flowing through the heater core 20 distributed by the air mix damper 21 and the second airflow flowing through the heater core 20 by bypass is determined.

The proportion of the first airflow is determined by the following equation.

γ=Tao-Te/Th-Te...(2) Th: Air temperature immediately after the heater core Te: After-evaporator air temperature detected by the evaporator after-temperature sensor 29 Note that the temperature Th immediately after the heater core is determined by the engine cooling water temperature thermostat. It is determined from the engine cooling water temperature because it is controlled to a nearly constant temperature.

The control circuit 24 outputs a signal to the actuator 23 so that the air mix damper 21 reaches the first air flow rate γ, thereby controlling the vehicle interior temperature to a target value near the set temperature.

Generally, if the vehicle interior temperature can be controlled to the target temperature without turning on the compressor 40, the compressor 40 is turned off, and if the vehicle interior temperature cannot be maintained at the target temperature without turning on the compressor 40, the compressor 40 is turned on. do. In this case, immediately after the compressor 40 changes from ON to OFF, there is a delay in response due to the heat capacity of the evaporator rear temperature sensor 29, and the temperature Te detected by the evaporator rear temperature sensor 29 is lower than the actual air temperature as shown in Figure 4A. will also be lower. Therefore, the first
The airflow rate also deviates from its original value, and the blowout temperature temporarily rises. Therefore, in the present invention, the time t from the time when the compressor 40 changes from ON to OFF is
The actual post-evaporator air temperature is calculated from the temperature detected by the post-evaporator temperature sensor 29.

If the actual air temperature after the evaporator is Te′ ₁ , it is calculated as Te′ ₁ = Te−(te−Ton)e ^−At (3).

Te: Temperature detected by the evaporator rear temperature sensor Ton: Evaporator rear air temperature when the compressor is ON A is a constant Here, Ton is read by the control circuit 24 and written to the memory when the compressor is ON. That is, before the control circuit 24 outputs an OFF signal to the compressor 40, it is read by the evaporator rear temperature sensor 29, and then outputs an OFF signal to the compressor 40.

Actual air temperature after the evaporator calculated from equation (3)
By substituting Te′ ₁ for Te in equation (2) to find the ratio γ of the first air flow described above, and controlling the air mix damper 21 so that the value of γ is reached, the compressor 40 changes from ON to This can prevent the blowout temperature from rising immediately after the switch is turned off.

Next, immediately after the compressor 40 is turned from OFF to ON, the evaporator post-temperature sensor 29 has a response delay due to the heat capacity of the sensor, and detects a value higher than the actual air temperature as shown in FIG. 4B. Therefore, the blowing temperature temporarily decreases even though the set temperature is not changed.

In the present invention, the compressor 40 changes from OFF to ON.
The actual post-evaporator air temperature is calculated from the time t from when the temperature changes to 1 and the temperature detected by the post-evaporator temperature sensor 29.

The actual air temperature after the evaporator in this case is
If Te′ ₂ , it is calculated as Te′ ₂ = (Toff−Te)e ^-At +Te ……(4).

Te: Temperature detected by the temperature sensor after the evaporator Toff: Temperature of the air after the evaporator when the compressor is OFF Here, Toff is read before the control circuit 24 sends the ON signal to the compressor 40, and then the ON signal is sent to the compressor 40. Obtained by putting out. Since Toff is approximately equal to the outside air temperature, the temperature detected by the outside air temperature sensor 26 may be used instead.

Actual air temperature after the evaporator determined from equation (4)
By substituting Te′ ₂ for Te in equation (2), the air mix damper 2 is adjusted so that the value of the first airflow ratio γ described above is obtained.
By controlling 1, the compressor 40
This can prevent the blowout temperature from dropping immediately after switching from OFF to ON.

Next, the program contents of the microcomputer in the control circuit 24 will be explained with reference to the flowchart of FIG. When the program is started, the process from step 50 (START) to step 80 (RESET) is repeatedly executed, but first, in step 60, it is determined whether the program is initialized. That is, it is determined whether this is the first processing after the program has been started, or whether START in step 50 and RESET in step 80 have already been executed and the process has reached step 60 again. If it is initial, initial processing is performed to clear flag C and perform other operations. This flag C is set when the compressor 40 is ON, and cleared when it is OFF.

In step 62, the input values from each sensor are read, and in step 63, the target air outlet temperature Tao to bring the vehicle interior temperature to a target temperature near the set temperature is calculated using equation (1).
Calculate according to. Next, the process moves to steps 64 and 65, where the compressor 40 is turned on or off.
Decide what to do. Generally, the target blowout temperature Tao
− Determine based on the value of outside air temperature Tam. Predetermined value T ₁ ,
If T ₂ (T ₁ >T ₂ ) and Tao-Tam is greater than T ₁ , the compressor 40 is turned on in step 74.
Turn off. If it is smaller than T ₂ , the compressor 40 is turned on in step 66. Tao−Tam is T ₁
If it is in the middle of _T2 , the process advances to step 73, at which time the current ON or OFF state of the compressor 40 is maintained. T ₁ -T ₂ is a hysteresis width to prevent the compressor 40 from turning on and off.

After turning off the compressor 40 in step 74, it is determined whether the value of flag C is 1 or not. If C=1, turn off the compressor 40 in step 74.
This means that the switch was ON before the switch was turned off, and since step 74 is the point at which the switch changes from ON to OFF, counter No. 1 is started to count the time from the switch from ON to OFF. At steps 77 and 78, read the time of counter No. 1 and use the formula
According to (3), calculate the actual air temperature Te′ ₁ after the evaporator. In step 79, the compressor 40
To remember that it is OFF, set C to 0. At step 72, adjust the air mix damper 2 so that the ratio γ of the first air flow is calculated using Te' ₁ .
Move 1.

If C is not 1 in step 75 (when C = 0), the compressor 40 is turned OFF in step 74.
This means that it was off even before the evaporator was turned off. At this time, the start signal is not sent to counter No. 1, and the time of counter No. 1, which has already started, is read and the actual air after the evaporator is turned off according to equation (3). Calculate the temperature Te′ ₁ .

When Tao-Tam is between _T2 and _T1 in steps 64 and 65, the compressor 40 remains in the same state, so it is not immediately after the compressor 40 changes from ON to OFF or from OFF to ON. Therefore, there is no need to start a counter that measures time, and it is sufficient to read the time using a counter that has already started. Compressor 40 determines whether to read counter No. 1 or counter No. 2.
Determined by whether it is OFF or ON. Therefore, the value of C is determined in step 73, and if C=0 (if compressor 40 is OFF), counter No. 1 is read in step 77.

If C=1 (compressor 40 is ON), counter No. 2 is read in step 69.

When Tao-Tam is smaller than _T2 in step 65, the compressor 40 is turned on in step 66. In step 67, it is determined based on the value of flag C whether the compressor 40 has been ON or OFF since before step 66. If C=0, in this case before step 66 the compressor 40
This means that the compressor 40 was turned OFF, and since this is immediately after the compressor 40 was turned ON in step 66, counter No. 2 is started in step 68 to measure the time from when the compressor 40 was turned OFF to immediately after it was turned ON. If C=1, the compressor 40 has already been in the ON state before step 66, so the counter
There is no need to start No. 2, step 69
Proceeding to step 70, the time already measured by counter No. 2 is read and the actual post-evaporator air temperature Te' ₂ is calculated according to equation (4). Then, in step 71, flag C is set.

Next, the ratio γ of the first air flow is determined using Te' ₂ , and in step 72 the air mix damper 21 is moved so as to obtain this value.

Although one embodiment of the present invention has been described above,
The present invention is not limited to this embodiment, and includes various embodiments within the scope of the claims.
Counter No. 1 and counter No. 2 may share one counter.

[Brief explanation of the drawing]

Fig. 1 is a complaint correspondence diagram, Fig. 2 is a schematic configuration diagram of an embodiment of the present invention, Fig. 3 is a flowchart showing the program contents of a microcomputer adopted in an embodiment, and Fig. 4 Both A and B are diagrams showing the detection characteristics of the post-cooling temperature sensor. 1...Ventilation duct, 2...In-vehicle air intake, 3...
...Vehicle outside air intake, 4...Inside and outside air switching damper, 6...
...Heater outlet, 7...Vent outlet, 8...Switching damper, 9,9'...Actuator, 10...
...Defroster outlet, 11...Switching damper, 12
...Electric motor, 13...Blower fan, 14...Blower fan control device, 15...Evaporator (heat exchanger for cooling), 19...Temperature adjustment mechanism, 20...Heater core (heat exchanger for heating), 21... ... Air mix damper, 23 ... Actuator, 24 ... Control circuit, 25 ... Temperature setting device, 26 ... Outside temperature sensor, 27 ... Vehicle interior temperature sensor, 28 ... Solar radiation sensor, 29 ... After evaporator Temperature sensor (temperature sensor after cooling), 40... Compressor (refrigerant supply device), 41... Condenser, 42... Expansion valve.

Claims (1)

[Scope of Claims] 1. A ventilation duct that introduces air from inside the vehicle interior or outside the vehicle interior and blows this air out to a suitable location within the vehicle interior. A cooling heat exchanger that lowers the temperature of flowing air, which is located downstream of the cooling heat exchanger in the air flow and is installed in the ventilation duct so as to occupy a part of one cross section of the ventilation duct. A heating heat exchanger that increases the temperature of the air, which divides the air flowing through the ventilation duct into air that flows through the heating heat exchanger and air that flows bypassing the heating heat exchanger, an air mix damper that adjusts the distribution ratio; a temperature setting device that is arbitrarily set to a desired temperature and generates a signal representing the set temperature; an outside air temperature sensor that detects outside air temperature and generates a signal representing the detected temperature; A vehicle interior temperature sensor that detects the interior temperature of the vehicle and generates a signal representing the detected temperature.A post-cooling temperature sensor that detects the air temperature downstream from the cooling heat exchanger through the air flow and generates a signal representing the detected temperature. A target outlet temperature calculation means that receives signals from a sensor, a temperature setting device, an outside air temperature sensor, and a vehicle interior temperature sensor, respectively, and calculates a target outlet temperature of a ventilation duct necessary for maintaining the vehicle interior temperature at a set temperature; A signal is received from the sensor and the target outlet temperature calculating means, and the outside air temperature is compared with the target outlet temperature. As a result, if the outside air temperature is lower than the target outlet temperature and the difference is more than a predetermined value, the cooling heat exchanger refrigerant supply control means that generates a signal to stop the supply of refrigerant to the cooling heat exchanger and, at other times, generates a signal to supply the refrigerant to the cooling heat exchanger; a refrigerant supply device that intermittents the supply of refrigerant to the refrigerant, a timer that receives a signal from the refrigerant supply control means and measures the time since refrigerant supply is started or stopped, and a clock that receives a signal from the cooling temperature sensor and the timer. , to correct the response delay of the after-cooling temperature sensor, calculate the actual after-cooling temperature based on the elapsed time from the start or stop of refrigerant supply and the temperature detected by the after-cooling temperature sensor. Receiving signals from the calculation means, the post-cooling temperature calculation means, and the target outlet temperature calculation means, calculates the distribution ratio of the air mix damper necessary to raise the air temperature downstream of the cooling heat exchanger to the target outlet temperature. A vehicle air conditioner comprising: distribution ratio calculation means for calculating; and an actuator that receives a signal from the distribution ratio calculation means and drives an air mix damper so as to achieve the calculated distribution ratio.