EXPANSION VALVE CONTROL METHOD, AND EXPANSION VALVE FOR VEHICULAR AIR CONDITIONING SYSTEM PARTICULARLY OPERATED WITH CO2 AS COOLANT

摘要

PROBLEM TO BE SOLVED: To provide a method of controlling an expansion valve for a vehicular air conditioning system which is particularly operated with CO2as coolant. SOLUTION: The expansion valve comprises a valve housing 31 having a supply opening 32 and a removal opening 36, a valve closing member 37 for closing a valve seat 41 of a passage opening 34 arranged between the supply opening 32 and the removal opening 36, and a resetting device 39 for operating on the valve closing member 37 in its closing direction. A low pressure side control element 42 assigned to the valve closing member 37 is activated on a low pressure side via a predetermined threshold value when low pressure rises or a temperature on the low pressure side rises, to actuate at least one actuation element 48. The actuation element 48 reduces the closing force of the resetting device 39 operating on the valve closing member 37. Thereby, the passage opening 34 is enlarged or arranged on the low pressure side and a passage 61 of a bypass valve 62 formed in parallel to the passage opening 34 is opened. COPYRIGHT: (C)2008,JPO&INPIT