Refrigeration cycle device for vehicle

Abstract

A refrigeration cycle device for a vehicle includes a condition detecting unit for detecting a condition that an inner pressure of the refrigerant cycle exceeds a control set pressure, and a pressure reducing unit for reducing a pressure of the refrigerant at a low pressure side of a refrigerant cycle when the condition is detected. For example, when the condition detecting unit detects the condition, the pressure reducing unit starts up a compressor of the refrigerant cycle so as to reduce the pressure at the low pressure side in the refrigerant cycle.

1 . A refrigeration cycle device for a vehicle, comprising: 
 a refrigerant cycle through which refrigerant circulates;    a condition detecting unit for detecting a condition that an inner pressure of the refrigerant cycle exceeds a control set pressure; and    a pressure reducing means for reducing a pressure of the refrigerant at a low pressure side of the refrigerant cycle when the condition is detected.    
   
   
       2 . The refrigeration cycle device according to  claim 1 , wherein the control set pressure is set lower than a set value that is set for a lowest withstanding pressure in the refrigerant cycle.  
   
   
       3 . The refrigeration cycle device according to  claim 1 , wherein: 
 the refrigerant cycle includes a relief device with a set pressure for protecting an equipment at the low pressure side in the refrigerant cycle; and    the control set pressure is set to be lower than the set pressure of the relief device.    
   
   
       4 . The refrigeration cycle device according to  claim 3 , wherein the control set pressure is set to be lower than the set pressure of the relief device for protecting the equipment at the low pressure side of the refrigerant cycle by 0.5 MPa or more.  
   
   
       5 . The refrigeration cycle device according to  claim 1 , wherein the control set pressure is set in a range between 7 MPa and 12 MPa.  
   
   
       6 . The refrigeration cycle device according to  claim 1 , wherein the control set pressure is set in prospect of an increase of the pressure in the refrigerant cycle.  
   
   
       7 . The refrigeration cycle device according to  claim 6 , wherein the control set pressure is set in prospect of an increase of the pressure in the refrigerant cycle due to residual heat of an engine of the vehicle after an ignition switch of the vehicle is set to OFF.  
   
   
       8 . The refrigeration cycle device according to  claim 6 , wherein: 
 the refrigerant cycle includes a relief device with a set pressure for protecting an equipment at the low pressure side in the refrigerant cycle; and    the control set pressure is set to be lower than the set pressure of the relief device by 1.0 MPa or more.    
   
   
       9 . The refrigeration cycle device according to  claim 1 , wherein the refrigerant cycle includes a compressor for compressing refrigerant, a gas cooler for cooling the refrigerant discharged from the compressor, and a cooling fan for blowing air to the gas cooler, the device further comprising 
 a control unit which controls operation of the refrigerant cycle, wherein    the pressure reducing means starts up at least one of the cooling fan and the compressor by the control unit when the condition detecting unit detects the condition, and reduces the refrigerant pressure at the low pressure side in the refrigerant cycle.    
   
   
       10 . The refrigeration cycle device according to  claim 1 , wherein the refrigerant cycle includes a displacement variable compressor for compressing refrigerant in the refrigerant cycle, the device further comprising 
 a control unit which controls operation of the refrigerant cycle, wherein    the pressure reducing means starts up the displacement variable compressor while a discharge capacity of the displacement variable compressor is controlled by the control unit when the condition detecting unit detects the condition.    
   
   
       11 . The refrigeration cycle device according to  claim 1 , wherein the refrigerant cycle includes a compressor for compressing refrigerant, the compressor being driven by using an engine of the vehicle as a driving source, the device further comprising 
 a control unit which controls operation of the refrigerant cycle, wherein    the pressure reducing means starts up the compressor by the control unit to reduce the refrigerant pressure at the low pressure side when the condition detecting unit detects the condition.    
   
   
       12 . The refrigeration cycle device according to  claim 11 , wherein the condition detecting unit detects the condition while an engine of the vehicle is operated under a state where an ignition switch of the vehicle is set to ON.  
   
   
       13 . The refrigeration cycle device according to  claim 9 , wherein the compressor is constructed with an electrical compressor driven electrically.  
   
   
       14 . The refrigerant cycle according to  claim 13 , wherein the condition detecting unit detects the condition under a state where an ignition switch of the vehicle is set to OFF.  
   
   
       15 . The refrigeration cycle device according to  claim 1 , wherein the refrigerant cycle includes a compressor for compressing refrigerant, a gas cooler for cooling the refrigerant discharged from the compressor, an evaporator for evaporating refrigerant after being decompressed, a first fan for blowing air to the gas cooler, and a second fan for blowing air to the evaporator, the device further comprising 
 a control unit which controls operation of the refrigerant cycle, wherein    when the condition detecting unit detects the condition, at least one of the first fan and the compressor is driven and the second fan is stopped by the control unit.    
   
   
       16 . The refrigeration cycle device according to  claim 1 , wherein the condition detecting unit includes a pressure detecting unit for detecting whether the refrigerant pressure in the refrigerant cycle reaches a predetermined value.  
   
   
       17 . The refrigeration cycle device according to  claim 16 , wherein the pressure detecting unit includes a discharge pressure sensor for detecting the refrigerant pressure at a discharge side of a compressor in the refrigerant cycle.  
   
   
       18 . The refrigeration cycle device according to  claim 1 , wherein the condition detecting unit includes a first temperature detecting unit for detecting whether a refrigerant temperature in the refrigerant cycle reaches a predetermined value.  
   
   
       19 . The refrigeration cycle device according to  claim 18 , wherein the first temperature detecting unit includes a discharge temperature sensor for detecting a refrigerant temperature at a discharge side of a compressor of the refrigerant cycle.  
   
   
       20 . The refrigeration cycle device according to  claim 18 , wherein the first temperature detecting unit includes at least one of a post-evaporation temperature sensor for detecting a temperature of air passed through an evaporator of the refrigerant cycle, a fin temperature sensor for detecting a temperature of a fin of the evaporator, and an air blow-out temperature sensor for detecting a temperature of air to be blown into a passenger compartment of the vehicle.  
   
   
       21 . The refrigeration cycle device according to  claim 1 , wherein the condition detecting unit includes a second temperature detecting unit for detecting whether any one of a temperature in an engine compartment of the vehicle and a temperature in a passenger compartment of the vehicle reaches a predetermined value.  
   
   
       22 . The refrigeration cycle device according to  claim 21 , wherein the second temperature detecting unit determines the temperature of the passenger compartment based on at least one of detection values of an inside air temperature sensor for directly detecting the temperature of air in the passenger compartment, an outside air temperature sensor for indirectly detecting the temperature in the passenger compartment, and a solar radiation temperature sensor for detecting a solar radiation amount entering into the passenger compartment.  
   
   
       23 . The refrigeration cycle device according to  claim 21 , wherein the second temperature detecting unit determines on the basis of the detection value of any one of an engine water temperature and an engine intake air temperature whether the temperature in the engine compartment reaches the predetermined value.  
   
   
       24 . The refrigeration cycle device according to  claim 1 , wherein the condition detecting unit includes a stop time detecting unit for detecting whether a stop time of a compressor of the refrigerant cycle reaches a predetermined time.  
   
   
       25 . The refrigeration cycle device according to  claim 1 , further comprising 
 a control unit for controlling operation of the refrigerant cycle, wherein    the control unit starts up at least one of a cooling fan for blowing air to a gas cooler, and a compressor of the refrigerant cycle when the condition detecting unit detects the condition, and then the control unit stops at least one of the compressor and the cooling fan during operation when a predetermined time elapses.    
   
   
       26 . The refrigeration cycle device according to  claim 1 , further comprising 
 a control unit for controlling operation of the refrigerant cycle, wherein    the control unit starts up at least one of a cooling fan for blowing air to a gas cooler and a compressor of the refrigerant cycle when the condition detecting unit detects the condition, and then the control unit stops at least one of the compressor and the cooling fan during operation when the control unit determines that a refrigerant pressure in the refrigerant cycle is equal to a predetermined value or less.    
   
   
       27 . The refrigeration cycle device according to  claim 1 , further comprising 
 a control unit for controlling operation of the refrigerant cycle, wherein    the control unit starts up at least one of a cooling fan for blowing air to a gas cooler and a compressor of the refrigerant cycle when the condition detecting unit detects the condition, and then the control unit stops at least one of the compressor and the cooling fan during operation when the control unit determines that the refrigerant temperature in the refrigerant cycle is equal to a predetermined value or less, or any one of a post-evaporation temperature, a fin temperature and an air blow-out temperature is equal to a predetermined value or less.    
   
   
       28 . The refrigeration cycle device according to  claim 1 , further comprising 
 a control unit for controlling operation of the refrigerant cycle, wherein    the control unit starts up at least one of a cooling fan for blowing air to a gas cooler and a compressor of the refrigerant cycle when the condition is detected, and then the control unit stops at least one of the compressor and the cooling fan during operation when the control unit determines that a temperature in an engine compartment of the vehicle or a temperature in a passenger compartment of the vehicle is equal to a predetermined value or less.    
   
   
       29 . The refrigeration cycle device according to  claim 25 , wherein when a predetermined time elapses after at least one of the compressor of the refrigerant cycle and the cooling fan is stopped, the condition detecting unit starts the detection.  
   
   
       30 . The refrigeration cycle device according to  claim 25 , wherein 
 when control unit determines the refrigerant pressure in the refrigerant cycle is equal to a predetermined value or less after at least one of the compressor and the cooing fan is stopped, the condition detecting unit starts the detection.    
   
   
       31 . The vehicle refrigeration cycle device according to  claim 25 , wherein, 
 when the control unit determines that any one of the refrigerant temperature in the refrigerant cycle reaches a predetermined value or a post-evaporation temperature, a fin temperature and an air blow-out temperature reaches a predetermined value after at least one of the compressor and the cooling fan is stopped, the condition detecting unit starts the detection.    
   
   
       32 . The refrigeration cycle device according to  claim 25 , wherein, 
 when the control unit determines that a temperature in an engine compartment of the vehicle or a temperature in a passenger compartment of the vehicle is equal to a predetermined value or less after at least one of the compressor and the cooling fan is stopped, the condition detecting unit starts the detection.    
   
   
       33 . The refrigeration cycle device according to  claim 1 , wherein the refrigerant cycle uses refrigerant containing carbon dioxide as a main component  
   
   
       34 . The refrigeration cycle device according to  claim 26 , wherein when a predetermined time elapses after at least one of the compressor of the refrigerant cycle and the cooling fan is stopped, the condition detecting unit starts the detection.  
   
   
       35 . The refrigeration cycle device according to  claim 27 , wherein when a predetermined time elapses after at least one of the compressor of the refrigerant cycle and the cooling fan is stopped, the condition detecting unit starts the detection.  
   
   
       36 . The refrigeration cycle device according to  claim 28 , wherein when a predetermined time elapses after at least one of the compressor of the refrigerant cycle and the cooling fan is stopped, the condition detecting unit starts the detection.