JPH01182114A - Air conditioner for vehicle - Google Patents

Abstract

PURPOSE:To enhance traveling of a vehicle or improve accelerating performance by stopping operation of a compressor in the case that a heat load is less than a defined value or a differential pressure between a high pressure side and low pressure side of the compressor is less than a defined value under an accelerating state of the vehicle and reducing a discharge capacity in the case that the differential pressure exceeds the defined value. CONSTITUTION:In the case that a judgement is made, that a heat load such as a room temperature, an outside air temperature, the quantity of solar radiation or the like detected by a detecting means 8 exceeds a defined value, an electronic controller 7 transmits a command to a driving circuit 6 for stopping a compressor. Further, in the case that, when an accelerating state of a vehicle is detected by an acceleration detecting means 12, a judgement is made by a judging means 10, that a differential pressure between a high pressure side and low pressure side of the compressor 2 detected by a differential pressure detecting means 9 is less than a defined value, a control means 11 also transmits a command to the driving circuit 6 for stopping the compressor 2. Besides, in the case that the differential pressure exceeds the defined value, the control means 11 outputs a command so that the refrigerant discharge capacity of the compressor 2 becomes smaller. With this arrangement, traveling of the vehicle or accelerating performance of the vehicle together with energy saving can be enhanced.

Description

[Detailed description of the invention] (Industrial application field) The present invention relates to a vehicle air conditioner.

(Prior Art) In general, a compressor is equipped with a compressor that can variably control the discharge capacity by communicating and cutting off the low-pressure chamber side and the high-pressure chamber side depending on the heat load, and is driven by an engine mounted on the vehicle. Vehicle air conditioners are well known.

In this type of conventional vehicle air conditioner, the compressor is driven by the engine mounted on the vehicle, so when the compressor is in use, that is, when the compressor is driven, the load on the engine is equal to the amount required to drive the compressor. increases, resulting in a corresponding decrease in the running output of the engine.

Therefore, as a vehicle air conditioner that aims to improve vehicle acceleration by controlling the discharge capacity of the compressor to the minimum when the vehicle accelerates, Japanese Patent Application Laid-Open No. 59-10261
There is one disclosed in Publication No. 7.

(Problem to be Solved by the Invention) In such a conventional vehicle air conditioner, if the heat load is small and the discharge capacity of the compressor is controlled to the minimum state, the compressor Even if an attempt is made to reduce the discharge capacity of the compressor, the discharge capacity of the compressor is actually at its minimum and will not become any smaller, so the acceleration of the vehicle will not be improved.

In addition, in the conventional vehicle air conditioner described above, the heat load is small and the differential pressure between the high pressure chamber side and the low pressure chamber side of the compressor is O
Since the operation of the compressor is not stopped even when the compressor reaches a state close to 1, there is a problem in terms of energy saving and a corresponding reduction in the running performance of the vehicle.

The present invention has been made in view of the above circumstances, and has a first object to provide a vehicle air conditioning system that can reliably improve the acceleration performance of a vehicle. A second object of the present invention is to provide a vehicle air conditioner that can improve the performance of the vehicle.

(Means for Solving the Problems) In order to achieve the above first object, the vehicle air conditioner of the present invention includes a differential pressure detection means for detecting the differential pressure between the pressure on the low pressure chamber side and the pressure on the high pressure chamber side. a differential pressure determining means for determining whether the differential pressure is equal to or higher than a predetermined value; an acceleration detecting means for detecting whether the vehicle is in an accelerating state; and when the acceleration detecting means detects an accelerating state. When the differential pressure determining means determines that the differential pressure is below a predetermined value, the operation of the compressor is stopped, and when the differential pressure determining means determines that the differential pressure is greater than a predetermined value, the discharge capacity of the compressor is controlled to be small. It is equipped with a control means.

In addition, in order to achieve the second object, the vehicle air conditioner of the present invention further includes a pressure difference detection means for detecting a pressure difference between a low pressure chamber side pressure J and a high pressure chamber side pressure, and a pressure difference detecting means for detecting a pressure difference between a low pressure chamber side pressure J and a high pressure chamber side pressure, and differential pressure determining means for determining whether the thermal load is equal to or higher than a predetermined value; thermal load determining means for determining whether the thermal load is equal to or less than a predetermined value; control means for controlling the compressor to stop operating when the means determines that the differential pressure is below a predetermined value, and to reduce the discharge capacity of the compressor when the differential pressure determining means determines that the differential pressure is equal to or higher than a predetermined value. This is what I did.

(Function) The vehicle air conditioner according to claim 1 configured as described above,
When the vehicle is in an accelerating state and the differential pressure between the pressure on the high pressure chamber side and the pressure on the low pressure chamber side of the compressor is below a predetermined value, the operation of the compressor is stopped and when the differential pressure is above the predetermined value. is controlled so that the discharge capacity of the compressor is reduced.

Further, in the vehicle air conditioner according to claim 2, when the heat load is below a predetermined value and the pressure difference between the high pressure chamber side pressure and the low pressure chamber side pressure of the compressor is below a predetermined value, the compressor When the operation is stopped and the differential pressure is above a predetermined value, the discharge capacity of the compressor is controlled to be small.

(Example) Embodiments of the present invention will be described below with reference to the accompanying drawings.

FIG. 1 is a block diagram showing a first embodiment of a vehicle air conditioner according to the present invention. In the figure, l is a cooling system, which includes a compressor 2, a condenser 3, an expansion valve 4, and an evaporator 5.
It is composed of etc. The compressor 2 can variably control the discharge capacity by communicating and cutting off the low-pressure chamber side and the high-pressure chamber side according to the heat load, and is also capable of controlling the discharge capacity of the vehicle (not shown).
It is driven by an engine mounted on the.

A drive circuit 6 is electrically connected to the compressor 2, and the drive circuit 6 is electrically connected to a microcomputer (hereinafter referred to as CPU) 7.

Further, a heat load detection means 8 for detecting heat loads such as room temperature, outside temperature, amount of solar radiation, etc. is electrically connected to the CPU 7,
The detection signal output from the heat load detection means 8 is
Input to U7.

Then, a control signal output from the CPU 7 corresponding to the thermal load detected by the thermal load detection means 8 is input to the drive circuit 6.

According to the control signal, the drive circuit 6 controls the compressor 2 and its discharge capacity.

The above configuration is the same as the conventional one, and the configuration described below is a novel point of the present invention.

A differential pressure detection means 9 is electrically connected to the compressor 2. The differential pressure detection means 9 is for detecting the differential pressure between the pressure on the low pressure chamber side of the Mj normal compressor 2 and the pressure on the high pressure chamber side. The differential pressure detecting means 9 is electrically connected to the differential pressure determining means 10, and a detection signal outputted from the differential pressure detecting means 9 is inputted to the differential pressure determining means 10. The differential pressure determining means lO determines whether the differential pressure is equal to or greater than a predetermined value α, and its determination signal is input to the control means 11. The control means 11 includes:
Acceleration detection means 1 for detecting whether the vehicle is in an acceleration state
The detection signal output from 2 is input.

The control means 11 turns off the compressor 2 described in 01j to stop its operation when the acceleration detection means 12 detects an acceleration state and the differential pressure determination means IO determines that the pressure difference is less than a predetermined value α; When the differential pressure determining means 10 determines that the differential pressure is equal to or higher than a predetermined value α, the compressor 2 is electrically connected to the drive circuit 6 to control the discharge capacity of the compressor 2 by M so that the discharge capacity becomes smaller.

Next, the operation of the vehicle air conditioner according to the present invention will be explained with reference to FIG. FIG. 2 is a flowchart showing the control routine.

First, when the vehicle air conditioner is powered on, the compressor 2 is driven, and after the refrigerant compressed by the compressor 2 is discharged from its discharge port, the path is from the condenser 3 → expansion valve 4 → evaporator 5. The air is then sucked in again from the suction port of the compressor 2, and refrigeration cycle operation is performed.

In this driving state, the acceleration detecting means 12 detects whether the vehicle is in an accelerating state (step I).

If the acceleration detection means I2 detects the acceleration state, the answer to step 1 becomes positive (Yes), and the differential pressure determination means 10 determines the differential pressure between the pressure on the low pressure chamber side and the pressure on the high pressure chamber side of the compressor 2. It is determined whether or not the differential pressure is greater than or equal to a predetermined value α (step 2). If the differential pressure determining means 10 determines that the differential pressure is greater than or equal to the predetermined value α, the answer to step 2 is affirmative (Yes), and the control means 11 issues a capacity reduction signal. is output (Step 3), and the compressor 2 is controlled by the drive circuit 6 so that its discharge capacity is reduced (Step 4).

Further, if the differential pressure determining means 10 determines that the pressure difference is less than or equal to the predetermined value α, the answer to step 2 is negative (No), and the compressor 2
is turned off (step 5) and its operation is stopped.

On the other hand, if the acceleration detecting means 12 does not detect an acceleration state, the answer to step I is negative (No), and the CPU 7
A normal discharge capacity setting signal is input to the drive circuit 6 according to the heat load (step 6), and the discharge capacity of the compressor 2 is controlled based on this signal (step 4).

In this way, when the vehicle is in an accelerating state, if the differential pressure between the low pressure chamber side pressure of the compressor 2 and the high pressure chamber [111 pressure] is equal to or less than the predetermined value α, the operation of the compressor 2 is stopped, and 6H
, By controlling the discharge capacity of the compressor 2 to be small when the differential pressure is equal to or higher than a predetermined value α, the load on the engine caused by the air conditioner is reduced, which improves the running performance of the vehicle and accelerates the vehicle. sex is improved.

Next, a second embodiment of the present invention will be described based on FIGS. 3 and 4. In this second embodiment, the same parts as those in the first embodiment described above will be described with the same reference numerals in the drawings. This second embodiment differs from the first embodiment only in that a thermal load determining means 13 is provided in place of the acceleration detecting means 12 in the first embodiment. The thermal load determining means 13 is for determining whether the thermal load detected by the thermal load detecting means 8 is equal to or less than a predetermined value β, and is electrically connected to the thermal load detecting means 8 and the control means 11. ing.

The operation will be explained based on the flowchart of the control routine shown in FIG. If the heat load determining means 13 determines that it is less than the predetermined value β, the answer to step l is
), and step 2 similar to the first invention is executed.

If the answer to step 2 is affirmative (Yes), that is, if the differential pressure is equal to or greater than the predetermined value α, steps 3 and 4 similar to the first invention are executed to reduce the discharge capacity of the compressor 2. controlled so that

Further, if the answer to step 2 is negative (NO), that is, if the differential pressure is less than or equal to the predetermined value α, step 5 similar to the first invention is executed and the operation of the compressor 2 is stopped. .

Furthermore, if it is determined that the heat load is greater than or equal to the predetermined value β,
The answer to step 1 is negative (NO), and steps 6 and 4 similar to the first invention are executed, and the discharge capacity of the compressor 2 is controlled according to the normal heat load.

In this way, when the heat load is below the predetermined value β, the operation of the compressor 2 is stopped if the differential pressure between the pressure on the low pressure chamber side and the pressure on the high pressure chamber side of the compressor 2 is below the predetermined value α. , and 0;
By controlling the discharge capacity of the compressor 2 to become smaller when the differential pressure (1) is equal to or higher than a predetermined value α, the load on the engine caused by the air conditioner is reduced, which not only saves energy but also improves the running performance of the vehicle. will improve.

(Effects of the Invention) Since the present invention is configured as described above, it produces effects as described below. In the vehicle air conditioner according to claim 1, when the vehicle is in an accelerating state, the operation of the compressor is stopped if the differential pressure between the pressure on the low pressure chamber side and the pressure on the high pressure chamber side of the compressor is equal to or less than a predetermined value. In addition, by controlling the discharge capacity of the compressor to become smaller if the differential pressure is above a predetermined value, the load on the engine caused by the air conditioner is reduced, which improves the running performance of the vehicle and improves acceleration. is improved.

In addition, in the vehicle air conditioner of claim 2, when the heat load is below a predetermined value, if the differential pressure between the low pressure chamber side pressure of the compressor and the high pressure chamber side pressure is below the predetermined value, the compression By stopping the operation of the machine and controlling the discharge capacity of the compressor to become smaller if the differential pressure is above a predetermined value, the load on the engine caused by the air conditioner is reduced, which results in energy savings. The driving performance of the vehicle is improved.

[Brief explanation of the drawing]

FIG. 1 is a block diagram showing a first embodiment of a vehicle air conditioner according to the present invention, FIG. 2 is a flowchart showing the same control routine, and FIG. 3 is a block diagram showing a second embodiment of the present invention. The circular diagram, FIG. 4, is a circular diagram of FIG. 2. 2...Compressor, 9...Differential pressure detection means, 10...Differential pressure determination means, 1]...Control means, 12...Acceleration detection means, I3...Heat load determination means. Applicant: Diesel Equipment Co., Ltd.

Claims (2)

[Claims] 1. In the vehicle air conditioner, the vehicle air conditioner is capable of variably controlling the discharge capacity by communicating and cutting off the low pressure chamber side and the high pressure chamber side according to the heat load, and is equipped with a compressor driven by an engine mounted on the vehicle. differential pressure detection means for detecting the differential pressure between the pressure on the low pressure chamber side and the pressure on the high pressure chamber side; differential pressure determination means for determining whether the differential pressure is equal to or higher than a predetermined value; acceleration detection means for detecting an acceleration state; 1. A vehicle air conditioner comprising: control means for controlling the discharge capacity of the compressor to be reduced when it is determined that the discharge capacity is greater than or equal to a predetermined value. 2. In the vehicle air conditioner, the vehicle air conditioner is capable of variably controlling the discharge capacity by communicating and cutting off the low pressure chamber side and the high pressure chamber side according to the heat load, and is equipped with a compressor driven by an engine mounted on the vehicle. differential pressure detection means for detecting a differential pressure between a low pressure chamber side pressure and a high pressure chamber side pressure; a differential pressure determining means for determining whether the differential pressure is a predetermined value or more; and a differential pressure determining means for determining whether the thermal load is below a predetermined value. a thermal load determining means for determining whether the differential pressure is lower than a predetermined value; 1. A vehicle air conditioner comprising: control means for controlling the discharge capacity of the compressor to be reduced when the determination means determines that the discharge capacity is equal to or greater than a predetermined value.