Heat exchange – With vehicle feature – Heating and cooling
Patent
1998-01-02
2000-03-28
Lazarus, Ira S.
Heat exchange
With vehicle feature
Heating and cooling
165 41, 165202, 165 43, 62244, B60H 300
Patent
active
060418494
DESCRIPTION:
BRIEF SUMMARY
CROSS-REFERENCE TO RELATED APPLICATIONS
The present application claims the benefit of previously filed French patent application 96.01164 filed in France on Jan. 31, 1996 and PCT international application FR97/00083 filed on Jan. 17, 1997 to which the instant application corresponds.
FIELD OF THE INVENTION
This invention relates to a method for modifying the temperature of a stream of air to be delivered into the cabin of a vehicle, by heat exchange with an evaporator in which there flows a fluid which also passes through a compressor and through an expansion device, the said method including a cooling mode for cooling the stream of air, in which the said fluid is caused to flow through, in succession, the evaporator, the compressor, a condenser in which it yields heat to another medium, and an expansion device.
BACKGROUND OF THE INVENTION
Such a method is conventionally used for the air conditioning of the cabin of the vehicle, especially a vehicle having a heat engine or an electric motor. When heating of the air to be passed into the cabin is required, the heat produced by the engine is commonly used, for example by causing the stream of air in contact with a heating radiator through which a coolant fluid for the engine passes.
When the engine is cold, it is not possible to draw heat from it for heating the cabin, and this delays the achievement of the desired temperature in the latter and is therefore detrimental to the comfort of the occupants. In some cases, the coolant liquid never does reach a high enough temperature during the journey to give a comfortable temperature in the cabin.
In order to get the cabin up to temperature more quickly, recourse can be had to additional devices, in particular those comprising burners or electric radiators, which involve high costs.
FR-A-2 717 126, on the other hand, proposes modification of the process by a heating mode for the stream of air, in which the fluid leaving the compressor is passed to the evaporator without passing through a condenser.
The heating mode that can be used for heating the cabin, especially when the engine is cold, thus depends on the existing air conditioning installation with minor modifications.
However, the calorific power generated in the heating mode is determined by the mass flow produced by the compressor, which is itself a function of the speed at which it is driven, and consequently a function of the running mode of the engine. This power can be either greater or less than that necessary for the heating of the cabin. In particular, in the event of starting at low temperature, the initial density of the fluid in the air conditioning circuit, and consequently the mass flow produced by the compressor, is insufficient to give satisfactory heating.
BRIEF SUMMARY OF THE INVENTION
The object of the invention is to adapt the calorific power produced by the evaporator to the heating demand of the vehicle, for all circumstances.
The invention is directed in particular to a method of the kind defined in the introduction hereof, and provides that, in the heating mode, the pressure of the fluid at the inlet of the evaporator is so controlled as to regulate the calorific power produced, and, when the mass of fluid flowing in the evaporator is insufficient to provide the required pressure, fluid is transferred from the condenser into the evaporator.
The invention firstly enables the calorific power to be adjusted up or down by virtue of the fluid pressure, and secondly it enables the reserve of fluid in the liquid state contained in the condenser to be used for augmenting the quantity of fluid flowing in the heating mode, in such a way as to augment the mass flow and the calorific power at a given speed of the compressor.
Optional features of the invention, complementary or alternative, are set forth below: controlled pressure regulator, implementing the control of the pressure of the fluid at the inlet of the evaporator, in the heating mode. heat exchanger in the heating mode. the heating mode is used for heating the cabin in those
REFERENCES:
patent: 4893748 (1990-01-01), Balducci
patent: 4909044 (1990-03-01), Gudmundsen
patent: 5085269 (1992-02-01), Aoki
patent: 5483807 (1996-01-01), Abersfelder
patent: 5488837 (1996-02-01), Sekino et al.
patent: 5528900 (1996-06-01), Prasad
patent: 5531264 (1996-07-01), Eike
patent: 5555737 (1996-09-01), Takeo et al.
Lazarus Ira S.
McKinnon Terrell
Valeo Climatisation
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