Vehicle air conditioner that operates during engine stops

Details Vehicle air conditioner that operates during engine stops Vehicle air conditioner that operates during engine stops

2002-11-20

2003-08-19

Tapolcai, William E. (Department: 3744)

Refrigeration

With vehicle feature

Occupant-type vehicle

C165S010000, C165S236000

Reexamination Certificate

active

06606877

ABSTRACT:

CROSS REFERENCE TO RELATED APPLICATION
This application is based upon, claims the benefit of priority of, and incorporates by reference the contents of prior Japanese Patent Application No. 2001-359586 filed Nov. 26, 2001.
BACKGROUND OF THE INVENTION
1. Technical Field of the Invention
The present invention relates to a cold thermal energy storage type vehicle air conditioner having a cold thermal energy storage unit cooled by cold air passed through a cooling evaporator, and the invention is applied to a vehicle whose vehicle engine, a driving source for a compressor is stopped when the vehicle stops moving.
2. Description of Related Art
Generally, for the purpose of environmental protection, a vehicle that automatically stops its engine when the vehicle stops moving, for example, to wait for a green light, has been commercially available. This vehicle is known as an eco-run or ecology running vehicle and an example of such a vehicle is a hybrid car. In the future, more vehicles are likely to exhibit the same engine stopping function when the vehicle stops.
In a vehicle's air conditioner, the compressor in the refrigeration cycle is driven by the vehicle engine, and therefore every time the above eco-run car stops moving, which stops the engine, the compressor also stops and the temperature in the cooling evaporator increases. This raises the temperature of air blown into the vehicle cabin, and reduces the comfort of the passengers as they cannot continue to feel cool enough because the increase in air temperature.
Therefore, there is an increasing demand for a cold thermal energy storage type vehicle air conditioner that includes a cold thermal energy storage unit. The cold thermal energy storage unit will store cold thermal energy during the operation of the compressor, and can cool air blown into the cabin by the cold thermal energy storage unit when the compressor is stopped (when the cooling function by the cooling evaporator stops).
SUMMARY OF THE INVENTION
This invention presents a cold thermal energy storage type vehicle air conditioner. If the cold thermal energy quantity stored in the cold thermal energy storage unit is small while the vehicle runs, there is only a short supply time for cooling air to be blown into the vehicle cabin at a comfortably low temperature when the engine is stopped. Therefore, the stored cold thermal energy quantity while the vehicle runs, that is, while the engine operates, must be known.
The invention is directed to a solution to the above problem. It is an object of the invention to provide a cold thermal energy storage type vehicle air conditioner that allows the quantity of cold thermal energy stored in the cold thermal energy storage unit during the operation of the vehicle engine to be accurately calculated. Another object of the invention is to provide a cold thermal energy storage type vehicle air conditioner that allows air conditioning control to be accurately carried out when the vehicle engine is stopped depending upon the stored quantity of cold thermal energy stored in the cold thermal energy storage unit.
In order to achieve the above object, according to a first aspect of the invention, in a vehicle air conditioner there is a cold thermal energy storage unit (
40
) provided on the downstream side of an evaporator (
9
) and cooled by cold air passed through the evaporator (
9
). The air blown into the cabin is cooled by a quantity of the stored cold thermal energy of the cold thermal energy storage unit (
40
) when the vehicle engine (
4
) is stopped. The cold thermal energy storage unit (
40
) has a cold thermal energy storage material (
44
) cooled and solidified by the cold air passed through the evaporator (
9
).
During the operation of the vehicle engine (
4
), the cold thermal energy storage time is measured. This is accomplished by measuring the time for the temperature of the cold thermal energy storage unit (
40
) to reach the solidifying point of the cold thermal energy storage material (
44
) or lower. The stored cold thermal energy quantity of the cold thermal energy storage material (
44
) during the operation of the vehicle engine (
4
) is calculated based on information including at least the cold thermal energy storage time and the volume of the cold air.
Meanwhile, cold thermal energy by latent heat is stored in response to the temperature of the cold thermal energy storage unit (
40
) reaching the solidifying temperature, or lower, of the cold thermal energy storage material (
44
). Therefore, the time after the temperature of the cold thermal energy storage unit (
40
) reaches the solidifying temperature, or lower, of the cold thermal energy storage material (
44
) and the volume of the cold air, are pieces of information most related to the cold thermal energy storage heat quantity of the cold thermal energy storage material (
44
). Therefore, the stored cold thermal energy quantity of the cold thermal energy storage material (
44
) is calculated based on information including at least the time after the temperature of the cold thermal energy storage unit (
40
) reaches the solidifying point, or lower, of the cold thermal energy storage material (
44
), i.e., the cold thermal energy storage time and the volume of cold air. Therefore, stored cold thermal energy quantity of the cold thermal energy storage material during the operation of the vehicle engine (
4
) can accurately be calculated.
Additionally, there is a temperature detecting means (
32
) for detecting the temperature of the evaporator (
9
) and a temperature detecting means (
33
) for detecting the temperature of the cold thermal energy storage unit (
40
). The stored cold thermal energy quantity is calculated based on the cold thermal energy storage time, the volume of the cold air, the temperature of the evaporator (
9
), and the temperature of the cold thermal energy storage unit (
40
).
Meanwhile, the stored cold thermal energy quantity of the cold thermal energy storage material (
44
) corresponds to the temperature of air of the cold thermal energy storage unit (
40
) before and after cold thermal energy storage. In other words, the quantity corresponds to the temperature difference before and after cold thermal energy storage. Therefore, the temperature difference between them (
9
,
10
) based on the temperatures of the evaporator (
9
) and the cold thermal energy storage unit (
40
) is taken into consideration in calculating the stored cold thermal energy quantity of the cold thermal energy storage material, and therefore the stored cold thermal energy quantity can more accurately be calculated.
According to another aspect of the invention, in a vehicle air conditioner in which there is a cold thermal energy storage unit (
40
) provided on the air downstream side of an evaporator (
9
) and cooled by cold air passed through the evaporator (
9
), and air blown into the cabin is cooled by the stored cold thermal energy quantity of the cold thermal energy storage unit (
40
) when the vehicle engine (
4
) is stopped, the cold thermal energy storage unit (
40
) has a cold thermal energy storage material (
44
) cooled and solidified by the cold air passed through the evaporator (
9
). During operation of the vehicle engine (
4
), the cold thermal energy storage completion time, after the temperature of the cold thermal energy storage unit (
40
) reaches the solidifying point, or lower, of the cold thermal energy storage material (
44
), that is, until cold thermal energy storage to the cold thermal energy storage material (
44
) is completed, is pre-set for each air volume of cold air.
During operation of the vehicle engine (
4
), the time passed, after the temperature of the cold thermal energy storage unit (
40
) reaches the solidifying point, or lower, of the cold thermal energy storage material (
44
), is measured. The pre-set cold thermal energy storage completion time is selected based on the actual cold air volume after the temperature of the cold thermal energy storage unit (
40
) reaches the solidifying point, or lower, of the

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