Internal heat exchanger for automotive air conditioner

Abstract

An internal heat exchanger for an automotive air conditioner which is capable of securing length of the internal heat exchanger necessary for heat exchange by a double pipe even when an evaporator and an expansion valve are disposed where the distance to a partition wall is short. Between an expansion valve and evaporator, and a partition wall, a first double pipe is disposed which is formed by surrounding an inner pipe connected to an inlet port of the expansion valve with an outer pipe connected to an outlet port of the evaporator, and a second double pipe is disposed within an engine room which is formed by surrounding an inner pipe with an outer pipe, in a manner extended from the first double pipe. The first double pipe and the second double pipe are connected by a pipe connecting member such that the connecting portions of the pipes are prevented from disconnection.

1 . An internal heat exchanger for an automotive air conditioner, for performing heat exchange between high-temperature, high-pressure refrigerant condensed within a refrigeration cycle, and low-temperature, low-pressure refrigerant evaporated within the refrigeration cycle, comprising:
 a first double pipe that is disposed between an inlet port of an expansion valve and an outlet port of an evaporator, arranged in a compartment of a vehicle, and a partition wall for separating an engine room of the vehicle and the compartment of the vehicle, such that a first outer pipe is disposed in a manner surrounding a first inner pipe;   a second double pipe that is disposed within the engine room, such that a second outer pipe is disposed in a manner surrounding a second inner pipe, said second inner pipe and said second outer pipe being connected to said first inner pipe and said first outer pipe at the partition wall; and   a pipe-connecting member that connects said first double pipe and said second double pipe such that connecting portions thereof are prevented from being disconnected from each other.   
   
   
       2 . The internal heat exchanger as claimed in  claim 1 , wherein said second double pipe has said second outer pipe joined to a joint member for connection to an intake pipe of a compressor, said second inner pipe being extended out through said joint member. 
   
   
       3 . The internal heat exchanger as claimed in  claim 2 , wherein said second inner pipe is integrally formed with a pipe for introducing high-temperature, high-pressure refrigerant. 
   
   
       4 . The internal heat exchanger as claimed in  claim 1 , wherein said first double pipe includes a connecting member being joined to said first inner pipe and said first outer pipe at an end of said connecting member opposite to a side where said first double pipe is connected to said second double pipe, whereby said connecting member has a hollow cylindrical body of a high-pressure passage formed to extend axially in an approximately central position of said first inner pipe such that a central opening of said hollow cylindrical body communicates with a space formed between said first inner pipe and said first outer pipe, and a low-pressure passage formed therethrough to an end face on a side where part of a periphery of said hollow cylindrical body is joined to said first inner pipe, and
 wherein said second double pipe closes a passage formed between said second inner pipe and said second outer pipe on a side opposite from a side where said first double pipe is connected to said second double pipe, and has a pipe joined thereto for introducing high-temperature, high-pressure refrigerant into the passage, said second inner pipe extended outward of a joint position of said second outer pipe and said pipe, to form a joint for being connected to an intake pipe of a compressor.   
   
   
       5 . An internal heat exchanger as claimed in  claim 1 , wherein said first double pipe has connecting members at respective opposite ends thereof, each connecting member having a hollow cylindrical body of a high-pressure passage formed to extend axially in an approximately central position of said first inner pipe such that a central opening of said hollow cylindrical body communicates with a space formed between said first inner pipe and said first outer pipe, and a low-pressure passage formed therethrough to an end face on a side where part of a periphery of said hollow cylindrical body is joined to said first inner pipe