JPH06262940A - Vehicle provided with air conditioner - Google Patents

Abstract

PURPOSE:To prevent undesired raise in the discharging pressure of a compressor by reducing the amount of air passing an evaporator when the air introduction is switched from a car interior to a car exterior. CONSTITUTION:When if is judged that the heat load of a refrigerating cycle having a compressor 12 add an evaporator 22, is no less than a predetermined level, and when it is detected that the air introduction to the evaporator 22 is switched from car interior to car exterior, by a controller 40, a blower fan control circuit 26 is controlled by the controller 40 so that the amount of air to be fed from a blower fan 23 to the evaporator 22 is reduced. The judgment whether the heat load is no less than the predetermined level, is carried out based on the discharging pressure of the refrigerant detected by a discharging pressure sensor 44.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a vehicle provided with an air conditioner in which a refrigerant compressed by a compressor is vaporized by an evaporator and a blower fan blows air to the evaporator to cool introduced air.

[Prior art]

A vehicle equipped with a compressor for compressing a refrigerant driven by an engine, an evaporator for evaporating the refrigerant compressed by the compressor, and a blower fan for passing the introduced air through the evaporator into the passenger compartment. Air conditioners are known. In a vehicle equipped with this type of air conditioner, for example, a valve (AAC valve) for adjusting the auxiliary air flow rate is provided in an air passage that bypasses the throttle valve, and this AAC valve is used when the compressor is operating (ON). The engine idle speed is increased by opening it at a fixed opening (for example, Nissan Service Weekly June 1987 No. 578 No. B-7).
1 page).

Further, in this type of vehicle air conditioner, the present applicant has previously disclosed in Japanese Patent Application No. 4-250297 that the increment of the engine idle speed is increased according to the heat load. Proposed a device. In this air conditioner, the heat load is estimated from the outside air temperature and the speed of the blower fan, and when the heat load is equal to or higher than the first predetermined value when the engine is idle, the engine idle speed is increased by ΔN1, and the heat load is When it is equal to or larger than a second predetermined value which is larger than the predetermined value, the engine idle speed is set to ΔN2.
Increase by (> ΔN ₁ ). By such control, the cooling capacity is increased by increasing the refrigerant flow rate when the heat load is large.

[0004]

However, when the air introduced into the evaporator is switched from the inside of the vehicle compartment to the outside of the vehicle compartment while the engine idle speed is increased by ΔN2, the outside air is high, such as midsummer. At times, the heat load may increase rapidly and the discharge pressure of the compressor may increase considerably.

An object of the present invention is to provide an air conditioner which reduces the amount of air passing through the evaporator when the introduced air is switched from the inside of the vehicle compartment to the outside of the vehicle compartment to prevent an undesired increase in compressor discharge pressure. It is to provide a equipped vehicle.

[0006]

Referring to FIG. 1, which is a diagram corresponding to claims, a vehicle equipped with an air conditioner according to the present invention includes a compressor 102 that is driven by an engine 101 to compress a refrigerant, and a compressor 102. An evaporator 103 for evaporating the compressed refrigerant and an evaporator 10 for introducing air introduced from the vehicle exterior or vehicle interior
Blower fan 104 for passing 3 to blow air into the passenger compartment
And a heat load determination means 105 for determining whether the heat load of the refrigeration cycle including the compressor 102 and the evaporator 103 is equal to or more than a predetermined value, and that the air introduced into the evaporator 103 is switched from the inside of the vehicle to the outside of the vehicle. When the switching load detecting means 106 for detecting and the thermal load judging means 105 judge that the thermal load is equal to or more than a predetermined value, and the switching detecting means 106 detects the switching of the introduced air, the blower fan 104 transfers to the evaporator 103. The above-described object is achieved by including the blown air amount reducing means 107 that reduces the blown air amount. A vehicle according to a second aspect of the present invention includes a rotation speed control unit 108 that increases at least the engine idle rotation speed when the compressor is operating. In the vehicle according to claim 3, the engine idle speed is set to the first speed when the compressor is not operating, and when the compressor is operating, the engine idle speed is set to the first speed when the determined heat load is a predetermined value or more. Second higher than
The rotation speed control means 108 for controlling the rotation speed is provided.

[0007]

When the air from the vehicle interior is blown to the evaporator 103 and the air conditioner is operated in a state where the heat load is high and the compressor discharge pressure is close to the allowable value,
When high-temperature air is introduced into the evaporator 103 from the outside of the passenger compartment, the amount of air blown to the evaporator 103 is reduced. As a result, the amount of work in the evaporator 103 is suppressed and the compressor discharge pressure does not exceed the allowable value. In the vehicle with an air conditioner according to claim 2, at least the idle speed is increased when the compressor is operating. When the idle speed is increased, the refrigerant flow rate is increased and the cooling capacity is increased.
Along with that, the compressor discharge pressure also rises. Considering that the outside air temperature and the temperature in the engine room are constant, the heat load is the most severe during engine idle-up operation and the compressor discharge pressure tends to be higher than during running. Therefore, when the above conditions are satisfied during idle-up operation, the amount of air blown to the evaporator is reduced, so that the work of the evaporator can be suppressed and the compressor discharge pressure is prevented from undesirably rising. In the vehicle of claim 3, the idle speed is increased when the engine is operating at the idle speed and the heat load is equal to or higher than a predetermined value when the compressor is operating.

[0008]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT An embodiment of the present invention will be described with reference to FIGS. In FIG. 2, a throttle valve 12 is provided in an intake passage 11 of an engine 10, and a passage 13 bypassing the throttle valve 12 is provided in the bypass passage 1.
An auxiliary air flow rate control valve (AAC valve) 14 for adjusting the amount of auxiliary air flow passing through the valve 3 is provided. AAC
The opening degree of the valve 14 is controlled by the controller 40,
The engine idle speed is controlled by adjusting the auxiliary air flow rate according to the operating state of the engine or the operating state of the air conditioner 20 described later.

Reference numeral 20 indicates an air conditioner, which is a compressor 2 driven by the engine 10.
1, an evaporator 22 that vaporizes a refrigerant compressed by the compressor 21 and supplied through a condenser, a liquid tank, and an expansion valve (not shown) to cool passing air, and a switching door 25 from outside the vehicle. A blower fan 23 that blows air or air from the vehicle interior through the evaporator 22 into the vehicle interior. The compressor 21 is turned on / off by a command from the controller 40 via the relay 24, and controls the discharge amount of the refrigerant in accordance with the required amount of cooling capacity. The compressor 21 may be a variable capacity type.

The blower fan 23 is driven by a blower fan applied voltage V _F applied via a blower fan control circuit 26 in response to a command from the controller 40. The blower fan control circuit 26 can be composed of, for example, a power transistor. Blower fan 23 speed (air volume)
Can be switched to four stages of Hi, MH, ML, and Lo in descending order of air volume, and as will be described later, the speed changes according to the target outlet temperature Xm during automatic control, but the blower fan switch is operated. When the voltage is set, the voltage V _F set by the switch is preferentially applied.

The controller 40 includes an outside air temperature sensor 41 for detecting the outside air temperature Tamb, an indoor temperature sensor 42 for detecting the passenger compartment temperature Tinc, a solar radiation sensor 43 for detecting the amount of solar radiation Qsun, and a discharge side conduit of the compressor 21. A discharge pressure sensor 44 for detecting the discharge pressure Pd of the refrigerant provided is connected, and an air conditioner switch 45 and a blower fan 23 operated when the compressor 21 is used.
A fan switch 46 for switching the operation / non-operation and the speed is also connected. Further, 47 is an air inlet selection switch, 48 is a temperature setting switch, and the inlet selection switch 47 selects an outside air introduction mode for introducing outside air from the outside of the vehicle or an inside air circulation mode for circulating air inside the vehicle, The temperature setting switch 48 sets the vehicle interior target temperature.

The controller 40 is an air conditioner switch 4
5, the compressor 21 is turned on / off and the speed (air volume) of the blower fan 23 is controlled according to the state of the blower fan switch 46 or the like and the heat load of the vehicle, and the air inlet is also selected, and the refrigerant discharge pressure Pd is selected. The command value of the engine idle speed is determined according to.

Next, the operation of this embodiment will be described with reference to the flow charts of FIGS. FIG. 3 shows the controller 40
The main part of the air conditioning control performed by
In step 1, whether or not the compressor 21 is on (operating) is determined from the state of the air conditioner switch 45, and if it is off (not operating), the idle speed command value Ne is set to the idle speed when the compressor is off in step S2. Number N ₀ (first
Is set to, for example, 650 rpm).
This command value Ne is used in idle speed control,
This will be described in detail with reference to FIG.

On the other hand, if the compressor 21 is on, the process proceeds to step S3, and the blower fan speed and the air inlet mode are determined. For example, the blower fan applied voltage V _F and the air inlet mode are determined according to the target blowout temperature Xm. The target outlet temperature Xm is calculated by, for example, Xm = (A + D) T'ptc + B.Tam + C.Q'sun-D.Tinc + E. Tam is the outside air temperature sensor 4
The external air temperature Tamb obtained from 1 is a value obtained by removing influences from other heat sources so as to correspond to the actual outdoor air temperature, Q'sun, is the solar radiation amount information Qsun from the solar radiation sensor 43.
Is corrected to a predetermined amount of heat information, T'ptc is a value obtained by correcting the set temperature Tptc set by the occupant with the temperature setting switch 48 according to the outside air temperature, and Tinc is the indoor temperature sensor 4
The vehicle interior temperature obtained from 2 and A to E are constants. Here, the target blowout temperature Xm decreases as the vehicle heat load increases.

When the blower fan speed is manually input by the blower fan switch 46, the blower fan applied voltage V _F is determined according to the operating position of the switch. During the auto control, the blower fan speed and the air inlet are determined based on the target outlet temperature, and the actual outlet temperature and outlet are controlled, but this control is not directly related to the present invention. Therefore, detailed description thereof will be omitted.

In step S4, the state mode is judged based on the refrigerant discharge pressure Pd on the compressor discharge side. P1 to P4 are set as reference values of the refrigerant discharge pressure Pd,
The state modes are A, B, C according to the value of the refrigerant discharge pressure Pd.
It is judged by either. In step S5, it is determined whether the air introduction mode is the outside air introduction mode or the inside air circulation mode, and if it is the outside air introduction mode, the process proceeds to step S6. In step S6, according to the state mode determined in step S4, the process proceeds to step S2 if it is state mode A, to step S7 if it is state mode B, and to step S8 if it is state mode C. In step S7, the idle rotation speed command value Ne is commanded to be N ₁ (corresponding to the second rotation speed, for example, 850 rpm) higher than N ₀ . In step S8, the idle rotation speed command value Ne is set to N ₂ higher than N ₁ (the third
Corresponding to the number of revolutions of 950 rpm).

After step S8, the process proceeds to step S9, and it is determined whether the inlet mode is switched from the inside air circulation mode to the outside air introduction mode. If an affirmative decision is made, the operation proceeds to step S10, in which a predetermined value V ₁ is subtracted from the blower fan applied voltage V _F determined in step S3 to obtain a corrected blower fan applied voltage V _FA , and the blower fan 23 is rotated by this V _FA. To drive. If step S5 is denied, step S1
According to the state mode determined in 1, the state mode A
If so, the process proceeds to step S12, if the state mode is B, the process proceeds to step S13, and if the state mode is C, the process proceeds to step S14.
As idle speed command values Ne, N ₀ , N ₁ , and
Set N ₂ .

FIG. 4 shows an essential part of the engine idle speed control procedure by the controller 40. In step S21, the idle speed command value Ne is determined, and Ne =
When it is determined that N _0, that is, idle up is not performed, in step S24, the opening degree of the AAC valve 14 is feedback-controlled so that the actual engine idle speed N becomes N ₀ (650 rpm). On the other hand, if it is determined that Ne = N ₁ in step S21, the AAC valve 14 is opened by a fixed value in step S22, and then the process proceeds to step S23, where the engine idle speed N
AAC valve 14 so that N becomes ₁ (750 rpm)
The opening degree of is controlled by feedback. Step S2
If Ne = N ₂ is determined in step 1, AA is set in step S25.
Open the C valve 14 by a constant value, and then step S26
And the engine idle speed is N ₂ (850 rp
The opening degree of the AAC valve 14 is feedback-controlled so that m).

As described above, in the present embodiment, the engine idle speed is set higher as the pressure Pd is higher in accordance with the refrigerant discharge pressure Pd when the compressor is used, and the refrigerating cycle is set to the refrigeration cycle based on the refrigerant discharge pressure. It is determined whether the heat load is a predetermined value or more. Then, during engine idle operation, when the air inlet mode is switched from the inside air circulation mode to the outside air introduction mode when the heat load is equal to or higher than a predetermined value, the speed of the blower fan is reduced by a predetermined value and the heat exchange amount in the evaporator is reduced. To lower the cooling capacity. Therefore, when the outside air is high and the refrigerant discharge pressure is quite high, such as on a midsummer day, the internal air circulation mode is switched to the outside air introduction mode during engine idle operation, and the amount of air passing through the evaporator is reduced even if the hot outside air is introduced to the evaporator. As a result, the work amount is reduced, and the refrigerant discharge pressure is prevented from undesirably increasing.

The processing procedure of FIG. 3 can be changed to that shown in FIG. 5 or 6. In FIG. 5, the idle speed is set to N ₂ when the compressor discharge pressure Pd is equal to or higher than P2 when the air conditioner is operating, and the idle up is performed when the discharge pressure Pd is lower than P2 even when the air conditioner is operating. There is no such thing. In FIG. 6, the idle-up is performed regardless of the compressor discharge pressure Pd when the air conditioner is operating. Also in the processing procedure of FIG. 5 and FIG. 6, when the internal air circulation mode is switched to the external air introduction mode during the idle-up operation, the blower fan air volume is reduced, the work of the evaporator 23 is reduced, and the compressor discharge pressure Pd is reduced. It is within the allowable value.

In the above, the amount of air blown to the evaporator is reduced when the above conditions are satisfied at idle-up. However, when an operation that increases the heat load on the refrigeration cycle, such as during low speed running on a midsummer day, is detected, The amount of air blown to the evaporator may be reduced to prevent the compressor discharge pressure from undesirably rising. In addition, the blower fan speed was reduced to reduce the air volume to the evaporator, but the blower fan speed was not changed, and the blower fan air flow was bypassed, resulting in a reduction in the flow rate into the evaporator. May be.

In the above embodiment, the controller 40
Constitutes a heat load detecting means, a switching detecting means, a blown air amount reducing means, and a rotation speed controlling means, respectively. Particularly, step S4 of FIG. 3 is the heat load detecting means, and step S9 is the switching detecting means. Step S10 is a means for reducing air flow,
Steps S2, 7, and 8 and the processing procedure of FIG. 4 constitute the rotation speed control means.

[0023]

According to the present invention, when the air introduced into the evaporator is switched from the inside of the vehicle to the outside of the vehicle when the heat load of the refrigeration cycle is greater than or equal to a predetermined value, the amount of air blown to the evaporator is reduced. Therefore, the work amount in the evaporator is reduced and the compressor discharge pressure is prevented from undesirably rising. Especially when the compressor is on,
In a vehicle equipped with the air conditioner according to claim 2 or 3, which increases the engine idle speed, when the compressor discharge pressure when the idle speed is increased is set to be considerably high, the outside air introduction is performed. Due to this, when high temperature air flows into the evaporator, the compressor discharge pressure may exceed the allowable value, but by reducing the air volume to the evaporator as in the present invention, the work of the evaporator is suppressed and the compressor discharge pressure is allowed. Can fit within.

[Brief description of drawings]

[Fig.1] Claim correspondence diagram

FIG. 2 is an overall configuration diagram of an embodiment of the present invention.

FIG. 3 is a flowchart showing an operation procedure example of an embodiment.

FIG. 4 is a flowchart showing a procedure example of engine idle speed control.

5 is a flowchart showing another embodiment of FIG.

FIG. 6 is a flowchart showing another embodiment of FIG.

[Explanation of symbols]

 10 Engine 13 Bypass Passage 14 Auxiliary Air Flow Control Valve 20 Air Conditioner 21 Compressor 22 Evaporator 23 Blower Fan 26 Blower Fan Control Circuit 40 Controller 41 Air Conditioner Switch 44 Discharge Pressure Sensor 47 Inlet Switch

Claims (3)

[Claims] 1. A compressor that is driven by an engine to compress a refrigerant, an evaporator that vaporizes the refrigerant compressed by the compressor, and air introduced from outside or inside the vehicle interior of the vehicle to pass through the evaporator to obtain a vehicle interior. A blower fan that blows air to the compressor, a heat load determination unit that determines whether the heat load of the refrigeration cycle including the compressor and the evaporator is equal to or greater than a predetermined value, and the air introduced into the evaporator is switched from the inside of the vehicle to the outside of the vehicle. The blower fan when the switching load is detected by the switching detection unit and the thermal load determination unit determines that the thermal load is equal to or greater than a predetermined value, and the switching detection unit detects the switching of the introduced air. An air conditioner for reducing the amount of air blown from the air to the evaporator. For example was the vehicle. 2. The vehicle according to claim 1, further comprising a rotation speed control unit that increases at least the engine idle rotation speed when the compressor is operating. 3. The vehicle according to claim 1, wherein the engine idle speed is the first speed when the compressor is not operating, and the engine idle speed is the first speed when the compressor is operating.
An air conditioner comprising a rotation speed control means for setting the engine idle rotation speed to a second rotation speed higher than the first rotation speed when the determined heat load is a predetermined value or more. Equipped vehicle.