JP2005297802A - Vehicular air-conditioner - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a vehicular air-conditioner capable of smoothly starting the heating cycle when the water temperature is low, and enhancing the immediately heating performance. <P>SOLUTION: In the vehicular air-conditioner having a sub condenser to radiate heat by selecting a heating line of a heat pump cycle as an auxiliary heater in addition to a heater core to heat conditioned air by circulating engine cooling water in an air-conditioning duct, if the heating operation is performed by utilizing the condensation heat by allowing the refrigerant to flow in a sub condenser when an engine is started at the condition where the temperature of engine cooling water is lower than the set value, an air-conditioning fan is driven at a low air volume A (Step 108), air is fed into the air-conditioning duct, and the rise of the heat pump cycle is expedited by promoting both heat reception in an evaporator and heat radiation in the sub condenser. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a vehicle air conditioner in which two main and sub capacitors are inserted in a heat pump cycle, and the sub capacitor is used as an auxiliary heater in an air duct in an air conditioning duct.

  A heat pump type vehicle air conditioner provided in a general vehicle connects a compressor, a condenser, an expansion valve, and an evaporator in this order in the refrigerant circulation path, and arranges the evaporator in the air passage in the air conditioning duct. Condensers are installed at locations where external air flows (arranged side by side with the radiator), and a heater core that heats the air-conditioning air by circulating engine cooling water downstream of the evaporator in the air-conditioning duct is provided. ing.

  In this type of vehicle air conditioner, the cool air cooled by the evaporator is blown out into the vehicle as it is during cooling, and the air cooled and dehumidified by the evaporator is reheated by the heater core and blown out into the vehicle interior during heating.

  However, in the case of a vehicle equipped with a low water temperature engine such as a diesel vehicle, there may occur a situation where the heat supply to the heater core is insufficient, particularly when the engine is started in the cold season.

In view of this, a sub-capacitor is incorporated in the heat pump cycle in addition to the main capacitor, and this sub-capacitor is provided in the air conditioning duct as an auxiliary heater (see, for example, Patent Document 1). When the sub-capacitor is incorporated in the air conditioning duct in this way, when the heat supply to the heater core is insufficient, the sub-capacitor can release the heat of the refrigerant into the air-conditioning duct to compensate for the insufficient heating by the heater core. .
JP 2002-2111234 A

  By the way, when the engine is started at a low outside temperature and the heating operation is performed, if the air is blown by turning the air conditioning fan at the same time as the engine is started, a cold wind comes out from the air outlet to the passenger compartment, which makes the passenger uncomfortable. May give.

  Therefore, normally, the fan is stopped so as not to blow the wind into the passenger compartment until the engine coolant flowing through the heater core warms up. This fan stop control based on the cooling water temperature when the engine is started is referred to herein as low water temperature start control.

  However, when this low water temperature start-up control is applied to a vehicle air conditioner equipped with the above-described sub-capacitor as an auxiliary heater, until the air-conditioning fan sends out the wind, the heat received by the evaporator disposed in the air passage, the sub Since heat is not smoothly radiated from the condenser, it is difficult for the refrigerant to circulate in the heating cycle, and the amount of refrigerant circulation during the heating cycle does not increase. For this reason, the rise of the heat pump cycle is delayed, and the immediate warming performance is reduced.

  In consideration of the above circumstances, an object of the present invention is to provide a vehicle air conditioner that can smoothly start a heating cycle at a low water temperature, and that can immediately improve the warming performance.

  According to the first aspect of the present invention, a compressor, a condenser, an expansion means, and an evaporator are connected in this order in the refrigerant circulation path, and two condensers, a main condenser and a sub condenser, are connected as the condenser to the outlet of the compressor and the inlet of the expansion means. And a heat pump cycle provided with a flow path switching means for selecting one of the capacitors as a flow path at the branch from the compressor outlet to the main capacitor and the sub capacitor. The evaporator is disposed as a cooling means for the conditioned air in the air passage for sending the air from the air-conditioning fan to the passenger compartment as the heat radiating means to the outside air, and the conditioned air is provided downstream of the air-cooling means. As a heating means, a heater core through which engine cooling water circulates and the sub-coil When the cooling operation is performed, a cooling line through which the refrigerant flows through the main condenser as a flow path is selected by the flow path switching means, and during the heating operation by using the condensation heat of the refrigerant gas, the flow path switching means In a vehicle air conditioner that selects a heating line through which refrigerant flows through the sub-capacitor as a flow path, when the engine is started with the engine cooling water temperature lower than the set temperature, the refrigerant flows through the sub-capacitor and the heat of condensation is used. In the case of performing the heating operation by the above-mentioned, it is characterized by comprising a control means for driving the air conditioning fan with a low air volume A.

  A second aspect of the present invention is the vehicle air conditioner according to the first aspect, characterized in that the air volume A is set to an air volume necessary for normally starting the heating line.

  A third aspect of the present invention is the vehicle air conditioner according to the first aspect, characterized in that the air volume A is set to an air volume capable of promoting refrigerant circulation in the heating line.

  A fourth aspect of the present invention is the vehicle air conditioner according to the first aspect, wherein the air volume A is set to an air volume at which a discharge pressure of the compressor can be a predetermined pressure.

A fifth aspect of the present invention is the vehicle air conditioner according to the first aspect, wherein the control means includes:
(A) When starting the engine in a state where the engine coolant temperature is lower than the set temperature, when the refrigerant is passed through the sub-capacitor and heating operation is performed using the condensed heat, the air-conditioning fan is driven with a low airflow A. ,
(B) When starting the engine in a state where the engine cooling water temperature is lower than the set temperature, when performing the heating operation using only the heater core, the air conditioning fan is stopped or driven with an air flow B lower than the air flow A,
(C) When the engine coolant temperature is equal to or higher than a set temperature, the air-conditioning fan is normally controlled according to the air-conditioning load.

  Invention of Claim 6 is a vehicle air conditioner in any one of Claims 1-5, Comprising: The said control means is only when FOOT mode or DEF mode is selected as vehicle blowing mode, When the engine is started with the engine coolant temperature being lower than the set temperature, the air conditioning fan is driven with a low air flow A when the refrigerant is passed through the sub-condenser and heating operation is performed using the condensed heat. And

  According to the first aspect of the invention, even when the low water temperature is started, only when the heating operation is performed using the sub-capacitor, the air of the low air volume A is sent by the air conditioning fan. The heat dissipation in the sub-capacitor can be promoted together, the rise of the heat pump cycle can be accelerated, and the immediate warming performance can be improved.

  According to invention of Claim 2, a heating line can be normally operated rapidly.

  According to invention of Claim 3, the refrigerant | coolant circulation in a heating line can be rapidly made into a normal state.

  According to the invention of claim 4, the discharge pressure of the compressor can be quickly brought to a normal pressure.

  According to the invention of claim 5, since the air volume of the air-conditioning fan is appropriately controlled according to the conditions, the immediate warming performance can be improved without causing discomfort to the occupant.

  According to the invention of claim 6, since the air flow control of the low air volume A is performed only in the FOOT mode and the DEF mode, it is possible to improve the immediate warming performance while avoiding discomfort to the occupant as much as possible. Can do.

  Embodiments of the present invention will be described below.

  FIG. 1 is a flowchart showing the contents of fan control in the vehicle air conditioner of the embodiment, and FIG. 2 is a configuration diagram of the vehicle air conditioner.

  First, the mechanical configuration will be described with reference to FIG. 2. This vehicle air conditioner connects the compressor 1, the condenser 2, the expansion valve (expansion means) 7, and the evaporator 5 in this order in the refrigerant circulation path. Two capacitors, a main capacitor 21 and a sub capacitor 22, are connected as a capacitor 2 in parallel between the outlet of the compressor 1 and the inlet of the expansion valve 7, and a branch portion from the compressor 1 to the main capacitor 21 and the sub capacitor 22. Are provided with a three-way switching valve (channel switching means) 3 for selecting one of the capacitors 21 and 22 as a channel, and before the junction 6 from the main capacitor 21 and the sub capacitor 22 to the expansion valve 7. A heat pump cycle provided with check valves 12 and 13 for preventing the refrigerant from escaping to the capacitors 21 and 22, respectively. That. In the heat pump cycle, the reference numeral 4 indicates a liquid tank, and the reference numeral 8 indicates an accumulator.

  The main condenser 21 is arranged as a heat radiating means to the outside air at a place where the outside air circulates (the same place as the radiator), and air conditioning for sending wind (shown by a white arrow) by an air conditioning fan (not shown) into the passenger compartment. The evaporator 5 is disposed as a cooling means for the conditioned air in the air duct 51 in the duct 50, and the cooling water of the engine is circulated as a heating means for the conditioned air in the hot air forming passage 55 on the downstream side thereof. The heater core 52 for heating the conditioned air and the sub capacitor 22 in the heat pump cycle are arranged. Further, in the air conditioning duct 50, a cold air bypass channel 56 is provided in parallel with the hot air forming channel 55, an air mix door 57 is provided on the front side of these channels, and a blower fan 58 is provided on the upstream side of the evaporator 5. Provided.

  In this vehicle air conditioner, during the cooling operation, the switching valve 3 selects the cooling line L1 through which the refrigerant flows through the main capacitor 21 as a flow path, and during the heating operation using the condensed heat of the refrigerant gas, the switching valve 3 operates. A heating line L2 is selected through which the refrigerant flows through the sub capacitor 22 as a flow path.

  In the vehicle air conditioner having such a configuration, during the cooling operation, the refrigerant is the compressor 1 → the three-way switching valve 3 → the main condenser 21 → the junction 6 → the expansion valve 7 → the evaporator 5 → the path of the compressor 1 (the cooling line L1). ) Further, during the heating operation using the heat of condensation of the refrigerant gas, the refrigerant flows from the compressor 1 → the three-way switching valve 3 → the sub capacitor 22 → the junction 6 → the expansion valve 7 → the evaporator 5 → the compressor 1 (heating line) L2).

  The vehicle air conditioner of the present embodiment is characterized by the control content of a fan control means (not shown). The contents of the control will be described with reference to the flowchart of FIG.

  The fan control means controls the air conditioning fan according to the steps of the illustrated flowchart. When this control routine is started, it is checked in step 101 whether the ignition switch (IG) is ON. If it is ON, it is checked in step 102 whether the air conditioner switch (A / C) is ON. If it is ON, it is checked in step 103 whether the engine coolant temperature is equal to or lower than the set temperature of the low water temperature start control. When the temperature is higher than the set temperature, the routine proceeds to step 104 where normal fan control is executed.

  If the water temperature is equal to or lower than the set temperature of the low water temperature start control, it is checked in step 105 whether the heat pump operating condition is satisfied. That is, here, it is checked whether or not a command for executing the heating operation using the heating cycle L2 is issued.

  When the heating operation command using the heating cycle L2 (heat pump) is not issued, that is, when the heating operation command using only the heater core 52 is issued, the low water temperature start-up is performed at step 106. Control (low water temperature startup fan voltage control) is executed. In this low water temperature start control, the air conditioning fan is stopped or driven with a very low air volume B. If the water temperature exceeds the set temperature due to the execution of this control, the routine proceeds from step 107 to step 104, where normal fan control is executed.

  On the other hand, when the heating operation command using the heating cycle L2 (heat pump) is issued, that is, in the heating operation using the heat pump that heats the conditioned air using the heat of the sub capacitor 22 in addition to the heater core 52. If the command has been issued, the process proceeds to step 108, and heat pump fan voltage control for driving the air-conditioning fan at a low airflow A (however, A> B) is executed. Also in this case, if the water temperature exceeds the set temperature by the execution of this control, the process proceeds from step 109 to step 104 and the normal fan control is executed.

  Thus, even when the low water temperature is started, only when heating operation is performed using the sub-capacitor 22, the air with the low air volume A is sent by the air-conditioning fan. The heat release can be promoted together, the rise of the heat pump cycle can be accelerated, and the immediate warming performance can be improved. Moreover, since the low water temperature starting fan control is also executed as necessary, it is possible to avoid discomfort to the occupant as much as possible.

  FIG. 3 is a diagram showing a difference in characteristics between a conventional vehicle air conditioner and a vehicle air conditioner according to an embodiment of the present invention. The solid line is an embodiment of the present invention (when a fan voltage of 4 V is applied from the beginning), and the dotted line is a conventional example (when the fan voltage is initially set to ~ V). Any of the room temperature average, the FOOT outlet temperature, and the compressor discharge pressure Pd shows a tendency superior to that of the prior art in a short time after startup.

  It should be noted that discomfort to the occupant can be further reduced by executing the heat pump fan voltage control only when the in-vehicle blowing mode is the FOOT mode or the DEF mode.

  Further, as the air volume A, any one of the air volume necessary for normally starting the heating line L2, the air volume capable of promoting the circulation of the refrigerant in the heating line L2, and the air volume capable of causing the discharge pressure of the compressor 1 to become a predetermined pressure. It's better to set it.

It is a flowchart which shows the content of the fan control in the vehicle air conditioner of embodiment of this invention. It is a block diagram of the vehicle air conditioner of embodiment of this invention. It is a figure which shows the difference in the characteristic of the vehicle air conditioner of embodiment of this invention, and the vehicle air conditioner of a prior art example.

Explanation of symbols

1 Compressor 2 Capacitor 3 Three-way switching valve (flow path switching means)
5 Evaporator 6 Junction Point 7 Expansion Valve (Expansion Means)
21 Main capacitor 22 Sub capacitor 51 Air passage 52 Heater core L1 Cooling line L2 Heating line

Claims (6)

The compressor (1), the condenser (2), the expansion means (7), and the evaporator (5) are connected in this order in the refrigerant circulation path, and the main condenser (21) and the sub condenser (22) are connected as the condenser (2). Two capacitors are connected in parallel between the outlet of the compressor (1) and the inlet of the expansion means (7), and from the outlet of the compressor (1) to the main condenser (21) and the sub condenser (22). A heat pump cycle provided with a flow path switching means (3) for selecting one of the capacitors as a flow path at the branch;
The main capacitor (21) is disposed at a place where the outside air circulates as a heat radiating means to the outside air,
The evaporator (5) is disposed as a cooling means for the conditioned air in the air passage (51) for sending the air from the air conditioning fan into the passenger compartment, and the engine is cooled as a heating means for the conditioned air on the downstream side thereof. The heater core (52) through which water circulates and the sub capacitor (22) are arranged,
During the cooling operation, the flow path switching means (3) selects the cooling line (L1) through which the refrigerant flows through the main condenser (21) as the flow path, and during the heating operation using the condensation heat of the refrigerant gas, In the vehicle air conditioner for selecting the heating line (L2) through which the refrigerant flows with the sub-capacitor (22) as the flow path by the path switching means (3),
When starting the engine with the engine cooling water temperature lower than the set temperature, when performing a heating operation by using a refrigerant flowing through the sub-condenser and using the heat of condensation, a control means for driving the air-conditioning fan with a low airflow A is provided. A vehicle air conditioner comprising: The vehicle air conditioner according to claim 1,
The vehicle air conditioner is characterized in that the air volume A is set to an air volume necessary for normally starting the heating line. The vehicle air conditioner according to claim 1,
The vehicle air conditioner is characterized in that the air volume A is set to an air volume capable of promoting refrigerant circulation in the heating line. The vehicle air conditioner according to claim 1,
The vehicle air conditioner is characterized in that the air volume A is set to an air volume at which a discharge pressure of the compressor can be a predetermined pressure. The vehicle air conditioner according to claim 1,
The control means includes
(A) When starting the engine in a state where the engine coolant temperature is lower than the set temperature, if the refrigerant is passed through the sub-capacitor and heating operation is performed using the condensed heat, the air-conditioning fan is driven with a low air flow A. ,
(B) When starting the engine in a state where the engine coolant temperature is lower than the set temperature, in the case of performing the heating operation only by the heater core, the air conditioning fan is stopped or driven with the air volume B lower than the air volume A,
(C) When the engine coolant temperature is equal to or higher than a set temperature, the air conditioning fan is normally controlled according to the air conditioning load. The vehicle air conditioner according to any one of claims 1 to 5,
The control means allows the refrigerant to flow through the sub-condenser when the engine is started with the engine coolant temperature lower than the set temperature only when the FOOT mode or the DEF mode is selected as the in-vehicle blowing mode. The vehicle air conditioner is characterized in that when the heating operation is performed by using heat, the air conditioning fan is driven with a low air flow rate A.

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