JP2932314B2 - Air conditioning controller for vehicles with multiple evaporators - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to an air conditioning control device for a vehicle having an evaporator for cooling at the front and rear of a one-box car or the like.

(Prior Art) With the spread of one-box cars and the like, an air conditioner equipped with an evaporator for air cooling before and after (front and rear) of the vehicle is shown in, for example, Japanese Utility Model Publication No. 58-40411. In the case of a device having an evaporator at the front and the rear, it is possible to select between a case where both are operated simultaneously and a case where either one is operated.

(Problems to be solved by the invention) However, when either the front or the rear is selected,
Refrigerant from the unused evaporator also flows into the cooling cycle during driving and becomes overfilled, and there is a problem that the pressure and temperature of the high pressure side line increase.

In view of the above, an object of the present invention is to prevent an overfill state in a cooling cycle in the case of using one of them selectively.

(Means for Solving the Problems) In order to achieve the above object, a vehicle air-conditioning control device having a plurality of evaporators according to the present invention, as shown in FIG. It has two evaporators connected in parallel to the evaporator, and the evaporators are separately arranged at the front and rear of the vehicle, and electric expansion valves 5, 6 controlled by the degree of superheat are provided at the inflow side of each evaporator. In the provided vehicle air-conditioning control device, a pressure and temperature detecting means 100 for detecting the pressure and temperature of the high pressure line of the cooling cycle, and one-operation selecting means 110 for selecting one of the front or rear operation according to the behavior of the occupant, When one operation is selected by the one operation selecting means 110, the pressure / temperature detecting means 100
From the pressure detected from the temperature, supercooling degree calculating means 120 for calculating the degree of supercooling from the temperature, from this supercooling degree calculating means 120, the overfill state determination means 130 to determine whether the cooling cycle is in the overfill state, When the overfilled state is determined by the overfilled state determination means 130, the one-operation selecting means outputs the output to the stopped electric expansion valve of the stopped evaporator to be opened and the opened electric expansion is stopped. The valve opening control means 140 is provided.

(Operation) Therefore, according to the present invention, when the refrigerant in the high pressure line of the cooling cycle is detected as being overfilled during either one of the cooling operations, the stop-side electric expansion valve is opened, and the stop-side electric expansion valve is opened. Refrigerant flows into the evaporator, and the overfill state in the cooling cycle is eliminated.

(Example) Hereinafter, an example of the present invention will be described with reference to the drawings.

FIG. 2 shows a vehicle air conditioning control device 1 according to the present invention. The vehicle air conditioning control device 1 includes a compressor 2, a condenser 3, a liquid tank 4, a front-side electric expansion valve 5, There is a cooling cycle in which the rear electric expansion valve 6, the front evaporator 7, and the rear evaporator 8 are connected by piping. The evaporators 7, 8 are provided in an air conditioner (not shown) provided in front of and behind the vehicle connected in parallel with the compressor, and function to cool air.

The electric expansion valves 5 and 6 are provided on the upstream side of the evaporators 7 and 8 provided on the front and the rear, respectively, and the configuration thereof is as shown in FIG. Plunger 12 displaced against spring 11
And a needle 15 provided at the tip of the plunger 12 and having opening and closing joints 13a and 13b at both ends to control the opening degree in the through hole 14, and a spring 16 opposed to the plunger spring. The needle 15 is moved in proportion to the current applied to 10, the opening area changes, and the flow resistance changes. Also, this electric expansion valve 1
The refrigerant temperature detectors 17a, 17b and 18a, 18b provided on the inlet side and the outlet side of the evaporators 7, 8 control the superheat calculated by the controller 20 described below. Is done.

The control device 20 includes a microcomputer having a well-known configuration including an input circuit 20a, a calculation unit 20b such as a CPU, and an output circuit 20c, and a refrigerant temperature detector 17a at an entrance on the front side.
17b, the temperatures T _17a , T _17b , T _18a , T _18b from the refrigerant temperature detectors 18a, 18b at the rear entrance and exit from the pressure and temperature detectors 21, 22 provided in the high pressure line on the downstream side of the liquid tank The pressure P ₂₁ and the temperature T ₂₂ are input, respectively, and furthermore, a front signal for selecting one of the front and the rear and a selection signal of the operation selection switch 23 for the front and the rear, and a front for operating one of the front and the rear with priority. , A priority signal from the rear one priority switch 24 is input. Furthermore, although not shown, each switch of the air conditioner that operates the air conditioner is input, but it is not necessary because it is not specifically required.

The electric expansion valves 5 and 6 are operated and controlled in accordance with each control flow based on the respective input signals, and the control flow of the electric expansion valves 5 and 6 is as shown in FIG. When the switch of the air conditioner is turned ON, the control is started from a start step 50, and various data are input in a step 51. That is, a signal for starting air conditioning or a refrigerant temperature detector
Temperatures T _17a , T _17b , T _18a , T _18b from 17a, 17b, 18a, _18b ,
A selection signal or the like of one of the front and rear operation selection switches 23 is input.

In step 52, it is determined whether one of the front and rear operation selection switches 23 has been pressed and either one of the operations has been performed, and if not, the process proceeds to step 53, where the temperatures _T17a , _T17b , _T18a , opening of the front and rear of the electric expansion valve 5, 6 is calculated by calculating the degree of superheat from T _18b, step 5
Proceed to 4. In step 54, a value corresponding to the calculated opening degree is output to the respective electric expansion valves 5 and 6.

Further, the step 52, if either operation is determined, the temperature T _17a for one operation of the front or rear side, T _17b or T _18a, running by calculating the degree of superheat from T _18b Of the electric expansion valve 5 or 6 is calculated, and
Proceed to 56.

In step 56, a value is output to each of the electric expansion valves 5 and 6 in comparison with the calculated opening degree, and then the process proceeds to step 57.

In step 57, the overfill condition is determined by the pressure in the high pressure line.
Supercooling degree is calculated from the saturation temperature at P ₂₁ minus the temperature T ₂₂ of the high-pressure line, the process proceeds to step 58.

In step 58, a degree of supercooling, for example, a value of about 5 ° C. to 10 ° C., is determined as a predetermined value, and when the predetermined value is exceeded, it is determined that an overfill state has occurred. If it is determined that the vehicle is in the overfilled state, the process proceeds to step 59, where the opening degree calculation is determined, for example, in comparison with the overfilled state, and the process proceeds to step 60.

In step 60, an output is made so that the stopped electric expansion valve 5 or 6 is opened. Thereby, the refrigerant flows into the stopped evaporator 7 or 8, and the pressure in the high pressure line decreases,
As a result, the degree of supercooling decreases.

If it is determined in step 58 that the state is not overfilled, the process proceeds to step 61, and the stopped electric expansion valve 5 or 6 is kept closed.

As described above, the present invention can prevent the supercooled state by opening the stopped electric expansion valve and allowing the refrigerant to flow when the cooling cycle indicates the supercooled state during only one operation. It is.

FIG. 5 illustrates a priority cooling flow.
When the air conditioner switch is turned on, the start step
Control is started from 70, and various data are input in step 71. That is, the air conditioning start signal and the refrigerant temperature detector 17a,
Temperatures T _17a , T _17b , T _18a , and T 18b from 17b, 18a, and _18b , and a priority signal is input from one of the front and rear priority switches that operate one of the front and rear with priority.

In step 72, it is determined whether the priority signal of the front or rear one priority switch 24 that gives priority to either the front or the rear has been pressed, and if not pressed, the process proceeds to step 73, where both the front and the rear are both Normal control (steps 53 and 5 shown in the flow chart of FIG. 5 of the first invention)
4).

When the priority cooling switch 24 is depressed, the routine proceeds to step 74, where the priority side electric expansion valve 5 or 6 is controlled normally (the same as steps 53 and 54 shown in the flow of FIG. 5 of the first invention). Control) is performed, and the routine proceeds to step 75, where the non-priority non-priority electric expansion valve 5 or 6 is throttled,
The flow of the refrigerant is restricted, so that the refrigerant to the priority side is sent as necessary and sufficiently, and the shortage of the refrigerant is not at the priority side. For this reason, the cooling capacity on the priority side is sufficiently exhibited.

(Effects of the Invention) As described above, according to the present invention, when the pressure in the high pressure side line of the cooling cycle is detected as an overfill state during either one of the cooling operations, the electric expansion valve on the stop side is activated. When opened, the refrigerant flows into the evaporator on the stop side, which has an effect of eliminating an overfilled state in the cooling cycle.

[Brief description of the drawings]

1 is a functional block diagram of the present invention, FIG. 2 is a block diagram of the present invention, FIG. 3 is a sectional view of an electric expansion valve, and FIG. 4 is a control flow of a cooling cycle having the electric expansion valve according to the present invention. FIG. 5 is a priority cooling flow. 2 ... Compressor, 5,6 ... Electric expansion valve, 7,8 ... Evaporator, 20
…… Control device, 21 …… Pressure detector, 22 …… Temperature detector,
23: One operation selection switch, 24: One priority switch, 100: Pressure temperature detection means, 110: One operation selection means, 120: Supercooling degree calculation means, 130: Overfill state determination means, 140 ... Electric expansion valve opening control means.

Claims (1)

(57) [Claims] An evaporator having at least one compressor and two evaporators connected in parallel to the compressor is provided separately at the front and rear of the vehicle, and superheated on the inlet side of each evaporator. In a vehicle air-conditioning controller equipped with an electric expansion valve controlled in degrees, a pressure-temperature detecting means for detecting the pressure and temperature of a high-pressure line in a cooling cycle, and the operation of either the front or the rear of an occupant Means for selecting one operation by means of: a supercooling degree calculating means for calculating the degree of supercooling from the pressure and temperature detected by the pressure and temperature detecting means when one operation is selected by the one operation selecting means; Overfill state determining means for determining whether the cooling cycle is in an overfill state from the cooling degree calculating means; and when the overfill state is determined by the overfill state determining means, the one-way operation is selected. A stopped electric expansion valve opening control means that outputs to the stopped electric expansion valve of the stopped evaporator that has been stopped by the stage and opens the evaporator, and a plurality of evaporators characterized by comprising: Air conditioning control device for vehicles.