Air-conditioning system for vehicles

Abstract

The present invention relates to an air-conditioning system for vehicles, in which expansion means and an internal heat exchanger are formed integrally with each other or expansion means, an internal heat exchanger and an accumulator are formed integrally with one another in an air-conditioning system using carbon dioxide (CO 2 ) as refrigerant so as to minimize and simplify a refrigerant line, thereby reducing the cost and a loss of energy according to a reduction in the number of assembly processes thereof. The air-conditioning system includes a compressor, a gas cooler, expansion means and an evaporator as a refrigerant line for circulating refrigerant in this order.

1 . An air-conditioning system for vehicles, which comprises a compressor, a gas cooler, expansion means and an evaporator as a refrigerant line for circulating refrigerant in this order,
 wherein the expansion means comprises:   an expansion block having a first high-pressure flow passage connected with an outlet line of the gas cooler and a second high-pressure flow passage connected with an inlet line of the evaporator; and   an expansion valve mounted inside the expansion block and adapted to control the opening and closing degree of the second high-pressure flow passage according to temperature or pressure of refrigerant flowing in the first high-pressure flow passage,   the air-conditioning system comprising an internal heat exchanger integrally mounted on a side of the expansion block and adapted to heat-exchange high-pressure refrigerant flowing from the first high-pressure flow passage to the second high-pressure flow passage with low-pressure refrigerant flowing from the evaporator to the compressor.   
   
   
       2 . The air-conditioning system according to  claim 1 , wherein the expansion block includes a first low-pressure flow passage connected with an outlet line of the evaporator and a second low-pressure flow passage connected with an inlet line of the compressor. 
   
   
       3 . The air-conditioning system according to  claim 2 , wherein the internal heat exchanger includes:
 a low-pressure pipe of a predetermined length mounted on a side of the expansion block and adapted to connect an outlet of the first low-pressure flow passage and an inlet of the second low-pressure flow passage with each other; and   a high-pressure pipe of a predetermined length mounted on the side of the expansion block in a double-pipe structure with the low-pressure pipe and adapted to connect an outlet of the first high-pressure flow passage and an inlet of the second high-pressure flow passage with each other,   whereby the internal heat exchanger heat-exchanges low-pressure refrigerant flowing in the low-pressure pipe with high-pressure refrigerant flowing in the high-pressure pipe.   
   
   
       4 . The air-conditioning system according to  claim 3 , wherein the high-pressure pipe is mounted in the low-pressure pipe and has an end portion inserted into the first low-pressure flow passage and connected with the outlet of the first high-pressure flow passage and the other end portion inserted into the second low-pressure flow passage and connected with the inlet of the second high-pressure flow passage. 
   
   
       5 . The air-conditioning system according to  claim 1 , wherein the expansion block has an insertion hole formed between the first and second high-pressure flow passages for inserting the expansion valve thereto. 
   
   
       6 . The air-conditioning system according to  claim 5 , wherein a sealing cap is mounted on the insertion hole adapted to seal the insertion hole after the expansion valve is inserted and mounted into the insertion hole. 
   
   
       7 . The air-conditioning system according to  claim 2 , wherein the second high-pressure flow passage and the first low-pressure flow passage are formed adjacent to the side of the expansion block. 
   
   
       8 . The air-conditioning system according to  claim 1 , further comprising an accumulator mounted between an outlet of the evaporator and the internal heat exchanger. 
   
   
       9 . The air-conditioning system according to  claim 1 , wherein the expansion valve includes: a temperature-sensing part adapted to perform contraction and expansion by sensing temperature or pressure of the refrigerant; and a valve part adapted to control the opening and closing degree of the second high-pressure flow passage to adjust an amount of the refrigerant supplied to the evaporator according to the contraction or expansion of the temperature-sensing part. 
   
   
       10 . The air-conditioning system according to  claim 1 , wherein the temperature-sensing part is mounted on the first high-pressure flow passage of the expansion block. 
   
   
       11 . The air-conditioning system according to  claim 1 , wherein the internal heat exchanger includes:
 a low-pressure tank integrally formed on a side of the expansion block in such a way that the accumulator connected with the outlet line of the evaporator through the first low-pressure flow passage formed in the expansion block is mounted therein, the low-pressure tank having a second low-pressure flow passage formed on an outlet thereof in such a way that the refrigerant discharged from the accumulator flows to the inlet line of the compressor; and   a high-pressure pipe adapted to connect an outlet of the first high-pressure flow passage with an inlet of the second high-pressure flow passage, the high-pressure pipe being wound on the outer peripheral surface of the accumulator within the low-pressure tank,   whereby low-pressure refrigerant flowing in the low-pressure tank and high-pressure refrigerant flowing in the high-pressure pipe heat-exchange with each other.   
   
   
       12 . The air-conditioning system according to  claim 11 , wherein the accumulator includes:
 a vapor-liquid separation tank having an empty inside;   an inflow pipe adapted to communicate the first low-pressure flow passage formed in the expansion block with the inside upper portion of the vapor-liquid separation tank to thereby introduce the low-pressure refrigerant discharged from the evaporator into the vapor-liquid separation tank;   a vapor-liquid separation plate integrally formed on the lower end of the inflow pipe for separating the liquid refrigerant and the vapor refrigerant by scattering the low-pressure refrigerant introduced through the inflow pipe; and   an outflow pipe adapted to communicate the inside upper portion of the vapor-liquid separation tank with the inside of the low-pressure tank for discharging the vapor refrigerant of the vapor-liquid separation tank to the inside of the low-pressure tank.   
   
   
       13 . The air-conditioning system according to  claim 12 , wherein an outlet of the outflow pipe is opposed to the second low-pressure flow passage. 
   
   
       14 . The air-conditioning system according to  claim 2 , further comprising an accumulator mounted between the outlet of the evaporator and the internal heat exchanger in such a way that an outlet line of the accumulator is connected with the first low-pressure flow passage.