JP3414098B2 - Vehicle air conditioner - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a vehicle air conditioner for controlling the air mix door opening based on the air temperature downstream of an evaporator.

[0002]

2. Description of the Related Art In a vehicle air conditioner equipped with a compression refrigeration cycle including a compressor and an evaporator, the air conditioning air sent by a blower fan and the refrigerant flowing in the evaporator are heat-exchanged to cool and cool the air conditioning air. The conditioned air is reheated by the heater core and blown into the passenger compartment. The reheat amount of the conditioned air, that is, the amount of air passing through the heater core is adjusted by an air mix door, and the opening of the air mix door is controlled based on the air temperature (suction temperature) downstream of the evaporator (for example, Nissan Motor Co., Ltd.). New model car manual Y32-1, June 1991). There are the following two specific air mix door opening control methods. (1) Regardless of the operation / stop of the compressor, the temperature detected by the suction temperature sensor (intake sensor) is always used as the air mix door opening control parameter. (2) When the air conditioner switch is off (compressor stopped), the temperature detected by the intake sensor itself is shown, and when the air conditioner switch is on (compressor operated or stopped), a constant suction temperature (for example, 3 ° C.) is maintained regardless of the sensor output. It is used as an opening control parameter.

[0003]

[Problems to be Solved by the Invention] However, (1)
In this method, the driving frequency of the air mix door becomes high and there is a problem in durability of the air mix door actuator.
For example, the compressor repeatedly operates / stops within a short period of time depending on the conditions, and the suction temperature changes greatly each time, so if the air mix door opening control is performed using the sensor detection value itself, the compressor operation / stop will be Each time the air mix door is driven, the life of the air mix door actuator is shortened. On the other hand, in the method (2), even if the intake temperature changes due to changes in the vehicle running state and heat load when the air conditioner is switched on, the opening degree of the air mix door is controlled at a constant intake temperature, so The blowing temperature of the vehicle may change undesirably and give an occupant an uncomfortable feeling.

An object of the present invention is to provide an air conditioning system for a vehicle, which improves the durability of the air mix door actuator and prevents undesired changes in the blowout temperature.

[0005]

In order to achieve the above object, the vehicle air conditioner according to the invention of claim 1 cools the conditioned air by exchanging heat between the refrigerant and the conditioned air pumped by the compressor. The evaporator, the air mix door that adjusts the amount of cooled air-conditioning air passing through the heater, the sensor that detects the temperature related to the evaporator, and the output values of the sensors that are sequentially output are subjected to a predetermined time delay processing, and the occupant compressor When the stop operation is performed, at least a predetermined time, the sensor value processing means for reducing the degree of time delay compared to before the compressor stop operation, and the air mix door control means for controlling the air mix door based on the output of the sensor value processing means. And. As described above, in the present invention, the air mix door is controlled based on not the detected value of the sensor itself but the value obtained by subjecting the detected value to a predetermined time delay process. According to the invention of claim 2, when the difference between the indoor temperature and the target temperature is judged to be a predetermined value or more, the degree of time delay is made lower than when the difference is judged to be less than the predetermined value. Is. According to the third aspect of the present invention, when the temperature detected by the sensor is equal to or higher than a predetermined value, it is determined that the difference between the indoor temperature and the target temperature is equal to or higher than the predetermined value. The invention of claim 4 further comprises compressor control means for controlling the operation / non-operation of the compressor based on the detection value of the sensor.

[0006]

BEST MODE FOR CARRYING OUT THE INVENTION An embodiment of the present invention will be described with reference to FIGS. FIG. 1 is a diagram showing an air conditioning cycle and a control system of a vehicle air conditioner according to the present invention. The refrigerant pressure-fed by the compressor 1 is guided to the evaporator 2 in the air conditioning duct 10 via a condenser, a liquid tank, and an expansion valve (not shown), flows through the evaporator 2 and returns to the compressor 1. The conditioned air sent by a blower fan (not shown) is cooled by exchanging heat with the refrigerant when passing through the evaporator 2, and the cooled conditioned air passes through the air mix door 3 and the heater core 4 and enters the vehicle interior. Blown out. The air mix door 3 adjusts the ratio of the amount of air that passes through the heater core 4 and the amount of air that does not pass through the heater core 4, and the temperature at which air blows into the vehicle interior is controlled by this.

Reference numeral 5 denotes an intake sensor for detecting an air temperature (suction temperature) Tint downstream of the evaporator 2.
The detected temperature Tint is input to the control circuit 21. The control circuit 21 is also inputted with respective detection outputs of a sensor group 22 including an outside air temperature sensor, an indoor temperature sensor, a solar radiation sensor and the like, a set temperature set by an occupant, etc., and based on these input values, the air mix door is inputted. The actuator 23 adjusts the opening of the air mix door 3, that is, the blowout temperature. At that time, particularly with respect to the suction temperature Tint, the sensor detection value is used after being subjected to a first-order lag filter as described later.

The intake temperature Tint detected by the intake sensor 5 is also input to the thermoamplifier 24, and when the manual air conditioner switch (not shown) is turned on, the thermoamplifier 24 uses the sensor detection value Tint itself. It controls the operation / stop of the compressor 1 and prevents the evaporator 2 from freezing. The compressor 1 is stopped when the air conditioner switch is turned off.

Next, the detailed procedure of the air conditioning control by the control circuit 21 will be described with reference to the flowcharts of FIGS. 2 and 3. FIG. 2 is a main flowchart. In step S1, variables and the like used for various calculations are initialized, and in step S2, detection values of the sensor group 22 and the intake sensor 5 are input. In steps S3 to S6, the output values of the outside air temperature sensor, the indoor temperature sensor, the intake sensor 5 and the solar radiation sensor are processed based on respective predetermined arithmetic expressions, and these are used as parameters to be used for calculation such as the target air mix door opening degree. Remember. The intake sensor value processing in step S5 will be described in detail later.

In step S7, the set temperature set by the occupant is corrected, and in step S8, the air mix door opening is calculated based on the above-mentioned sensor processing values and the set temperature correction value. The air mix door 3 is controlled via the air mix door actuator 23 so that In steps S9 to S12, blower outlet control, blower fan air volume control, compressor control, and suction inlet control are performed, and then step S2.
Then, the above process is repeated.

FIG. 3 is a flow chart showing the details of the intake sensor value processing in step S5. In step S51, it is determined whether or not immediately after the ignition is turned on. If negative, the process proceeds to step S52, and if positive, the output value (intake temperature detection value) Tint of the intake sensor 5 is set to the variable Tintc (t) in step S58. Store. This Tintc
(t) corresponds to the suction temperature processing value to be obtained in this control, and since it is the first control here, that value is set as the current suction temperature detection value Tint.

In step S52, it is determined whether or not the current suction temperature detection value Tint is 10 ° C. or higher, and step S53
Determines whether the air conditioner switch is on. Tint <
If it is determined that the temperature is 10 ° C. and the air conditioner switch is on, the process proceeds to step S54 to set the variable ti to “30 sec”, while if it is determined that Tint ≧ 10 ° C. or the air conditioner switch is off, the process proceeds to step S55 and the variable ti is set. Is set to “3 sec”. This ti corresponds to the time constant used in the first-order delay calculation formula in step S56, and the reason why the value is changed depending on the conditions will be described later.

In step S56, the suction temperature processing value Tintc (t) is calculated by the following equation.

[Equation 1] Tintc (t) = (Δt / ti) (Tint−Tintc (t-1)) − Tintc (t-1) where, Tint: Suction temperature detection value Tintc (t-1): Previous suction temperature Processed value Δt: Step time (for example, 0.3 seconds) ti: Time constant The above expression corresponds to a temporary delay filter for the suction temperature detection value Tint, and the relationship between Tint and Tintc (t) is shown in FIG.
As shown in (a).

In step S57, Tintc (t) calculated in step S56 or S58 is set as a parameter TINT for controlling the air mix door opening degree, and then the process returns to the process of FIG.

As described above, in the present embodiment, the suction temperature detection value Tint detected by the intake sensor 5 is obtained.
Is processed by the temporary delay filter, and the processed value Tintc
Since (t) is used as a parameter for controlling the air mix door, the driving frequency of the air mix door 3 is reduced as compared with the case where the detected value Tint itself is used. Hereinafter, this operation will be specifically described.

When the air conditioner switch is turned on, the operation / non-operation of the compressor 1 is controlled by the thermo-amplifier 24. When the operation / non-operation of the compressor 1 is repeated, the actual suction temperature, that is, the suction temperature is detected. The value Tint changes as shown by the solid line in FIG. If the air mix door opening control is performed using this Tint itself, the air mix door opening changes as shown by X1 in FIG. 4B, and the driving frequency of the air mix door 3 increases. .

On the other hand, the suction temperature processing value Tintc (t) output by applying Tint to the first-order lag filter is shown in FIG.
When the air mix door opening control is performed using this, the air mix door opening hardly changes as indicated by X2 in FIG. 4 (b). That is, the control circuit 21 is provided with a certain dead zone with respect to the input value of the suction temperature, and the change of Tintc (t) is substantially within this dead zone, so that the air mix door 3 is substantially constant. Held in position. Therefore, the durability of the air mix door actuator 23 can be improved as compared with the case where the detected value Tint itself is used. Since the temperature range of the dead zone is set in a range in which the blowout temperature does not change significantly even if the air mix door 3 is not driven, the occupant does not feel uncomfortable due to the change in the blowout temperature even if the above control is performed. Absent. Further, when the vehicle heat load is high, such as in the summer, Tintc (t) changes beyond the dead zone, but at this time, the air mix door 3 is driven to prevent a large change in the blowout temperature.

Further, in the present embodiment, when the suction temperature detection value Tint is 10 ° C. or higher, there is still a large difference between the indoor temperature and its target value immediately after the air conditioner is operated (the air conditioning state becomes stable. The time constant ti of the first-order lag filter is set to be smaller than that in the stable state. As a result, the degree of delay due to the filter is reduced, and Tintc
Since (t) changes in a state closer to the change in Tint, the indoor temperature can be brought closer to its target value quickly.

The time constant ti of the first-order lag filter is also reduced when the air conditioner switch is turned off even when the air conditioning condition is stable, that is, when the compressor is stopped by the occupant's intention. In this case, Tint is
However, if the time constant ti is still large, Tintc (t) changes slowly as shown by the alternate long and short dash line, so that the response delay of the air mix door 3 becomes large, and the passenger desires. It takes time to reach the temperature. If the time constant ti is reduced, Tintc (t) changes in a state closer to Tint as shown by the broken line, so that the temperature desired by the occupant can be quickly approached.

In the configuration of the above embodiment, the control circuit 21 constitutes the sensor value processing means, the control circuit 21 and the air mix door actuator 23 constitute the air mix door control means, and the thermoamplifier 24 constitutes the compressor control means. . Further, turning on / off the air conditioner switch corresponds to a compressor stop command issued by an occupant.

The arithmetic expression of the time delay filter is not limited to the embodiment. Further, the temperature relating to the evaporator is not limited to the above suction temperature, and may be, for example, the surface temperature of the evaporator. Furthermore, in the above, when the suction temperature detection value Tint is less than the predetermined temperature, it is determined that the air conditioning state is not stable, but this can also be determined from, for example, the target air mix door opening degree. Although the time constant ti is always made small when the air conditioner switch is turned off, ti is made small for a predetermined time after the air conditioner switch is turned off, and after a predetermined time elapses.
That is, ti may be restored after T int has stabilized.

[0022]

According to the present invention, the air mix door is controlled based on the value obtained by subjecting the temperature detecting sensor for detecting the temperature of the evaporator to a predetermined time delay process. The driving frequency of the air mix door can be reduced as compared with the case where the air mix door is controlled by using it, which contributes to the improvement of the durability of the air mix door actuator. Further, as compared with the case of performing control at a constant intake temperature, undesired changes in the outlet temperature are suppressed,
The occupant will not feel discomfort. Further, when the compressor stop operation is performed by the occupant, the degree of the time delay is made lower than that before the compressor stop operation at least for a predetermined time, so that the temperature desired by the occupant can be quickly approached. When the difference between the indoor temperature and the target temperature is determined to be a predetermined value or more, the degree of the time delay is made lower than when the difference is determined to be less than the predetermined value. You can get closer quickly.

[Brief description of drawings]

FIG. 1 is a diagram showing a configuration of a vehicle air conditioner according to an embodiment of the present invention.

FIG. 2 is a main flowchart showing a procedure of air conditioning control.

FIG. 3 is a flowchart showing details of intake sensor value processing.

FIG. 4 is a view showing a temporal change of suction temperatures Tint and Tintc (t) and a temporal change of an air mix door opening degree.

FIG. 5 is a diagram showing temporal changes in Tint and Tintc (t) when the air conditioner switch is turned off.

[Explanation of symbols]

1 compressor 2 evaporator 3 air mix door 4 heater core 5 Intake sensor 10 Air conditioning duct 21 Control circuit 22 sensor group 23 Air Mix Door Actuator 24 Thermo Amplifier

─────────────────────────────────────────────────── ─── Continuation of front page (56) Reference JP 58-174013 (JP, A) JP 61-193916 (JP, A) JP 60-15216 (JP, A) JP 61- 98607 (JP, A) JP-A-6-99720 (JP, A) JP-A-7-228127 (JP, A) JP-A-53-15868 (JP, A) Actual Kaihei 3-343308 (JP, U) (58) Fields surveyed (Int.Cl. ⁷ , DB name) B60H 1/00 103 B60H 1/00 101 B60H 1/00 102

Claims (4)

(57) [Claims] 1. An evaporator for cooling the conditioned air by exchanging heat between the refrigerant and the conditioned air sent by a compressor, an air mix door for adjusting the amount of the cooled conditioned air passing through a heater, and the evaporator. a sensor for detecting a temperature, and facilities the detection value predetermined time lag processing of the sensor sequentially outputted, the compressor stop operation by the occupant is performed
And, at least a predetermined time than before the compressor stop operation
Also including a sensor value processing unit that reduces the degree of the time delay, and an air mix door control unit that controls the air mix door based on the output of the sensor value processing unit. . 2. The sensor value processing means sets the degree of the time delay when the difference between the indoor temperature and the target temperature is judged to be a predetermined value or more than when the difference is judged to be less than the predetermined value. The vehicle air conditioner according to claim 1, wherein the air conditioner is lowered. 3. The sensor value processing means determines that the difference between the indoor temperature and its target temperature is a predetermined value or more when the temperature detected by the sensor is a predetermined value or more. The vehicle air conditioner described. 4. The vehicle air conditioner according to claim 1, further comprising a compressor control unit that controls operation / non-operation of a compressor based on a detection value of the sensor.