초록 ▼

A control apparatus for a gas injection type air conditioning system that prevents lowering of compressor speed and cycle stoppage under conditions where high pressure is liable to occur. During a system heating mode, a pressure change rate ASP of the high pressure of the refrigerating cycle is calc

A control apparatus for a gas injection type air conditioning system that prevents lowering of compressor speed and cycle stoppage under conditions where high pressure is liable to occur. During a system heating mode, a pressure change rate ASP of the high pressure of the refrigerating cycle is calculated. When a pressure change rate .increment.SP rises above a predetermined value, a system electric expansion valve aperture is reduced. Accordingly, by calculation of the pressure change rate .increment.SP, it is possible to control the electric expansion valve in the above manner earlier than in prior art control schemes when there is a sudden rise in the high pressure.

대표청구항 ▼

[ What is claimed is:] [1.] An air conditioning system, comprising:a blower for creating an air current;an air-conditioning duct that guides air produced by the blower into a compartment;a compressor having an intake port for taking in low-pressure refrigerant of a refrigerating cycle, a gas injecti

[ What is claimed is:] [1.] An air conditioning system, comprising:a blower for creating an air current;an air-conditioning duct that guides air produced by the blower into a compartment;a compressor having an intake port for taking in low-pressure refrigerant of a refrigerating cycle, a gas injection port for introducing intermediate pressure gas refrigerant of the refrigerating cycle, and a delivery port (22a) for delivering compressed high-pressure refrigerant;an inside heat exchanger mounted inside the air-conditioning duct for condensing high-pressure refrigerant from the delivery port of the compressor during heating;first pressure-reducing means for pressure-reducing high-pressure refrigerant from the inside heat exchanger to an intermediate pressure via an electrically-adjustable aperture;a gas-liquid separator for gas-liquid separating intermediate pressure refrigerant from the first pressure-reducing means;second pressure-reducing means for pressure-reducing intermediate pressure liquid refrigerant separated in the gas-liquid separator to a low pressure;an outside heat exchanger for evaporating low-pressure refrigerant from the second pressure-reducing means during heating;a gas injection passage for guiding intermediate pressure gas refrigerant separated in the gas-liquid separator to the gas injection port of the compressor;compressor speed controlling means for controlling an operating speed of the compressor; andcontrolling means for controlling the aperture of the first pressure-reducing means, for calculating, during heating, a pressure change rate based on information relating to high pressure of the refrigerating cycle, and for reducing the aperture of the first pressure-reducing means when the pressure change rate rises above a first predetermined value.