Automatic air conditioning system with variable displacement compressor, for automotive vehicles

An automatic air conditioning system for automotive vehicles with a variable displacement compressor, said compressor being operated in such a manner that, when the suction pressure of said compressor exceeds a preset pressure, the discharge of said compressor is increased, and when said suction pressure is equal to or is lower than said preset pressure, said discharge is decreased, comprising:

• first detecting means for detecting a first physical quantity which is indicative of a cooling condition of an evaporator of said automatic air conditioning system;
• first signal generating means for generating a first signal indicative of a requirement for quick-cooling;
• second signal generating means for generating a second signal indicative of the difference between said first physical quantity and its preset value;
• preset pressure changing means for changing said preset pressure in response to said second signal;
• and
• preset value changing means for changing said preset value of said first physical quantity in such a manner that, when said preset value changing means does not receive said first signal, the preset value is set to a first value at which an intake air temperature, defined by the temperature of air flowing through said evaporator as measured just behind said evaporator, reaches a freezing start possible temperature, an intake air temperature such that the freezing of said evaporator starts, and when said preset value changing means receives said second signal, the preset value of said first physical quantity is set to a second value at which said intake air temperature reaches a predetermined temperature lower than said freezing start possible temperature.

An automatic air conditioning system for automotive vehicles with a variable displacement compressor comprising:

• discharge means for compressing and discharging refrigerant;
• first detecting means for detecting a first physical quantity which is indicative of a cooling condition of an evaporator of said automatic air conditioning system;
• discharge changing means for changing discharge of refrigerant in such a manner that, when said first physical quantity exceeds a preset value, the discharge of said discharge means is essentially increased, and when said first physical quantity is equal to or is lower than said preset value, said discharge is essentially decreased;
• first signal generating means for generating a first signal indicative of a requirement for quick-cooling;
• and
• preset value changing means for changing said preset value of said first physical quantity in such a manner that, when said preset value changing means does not receive said first signal, the preset value of said first physical quantity is set to a first value at which an intake air temperature defined by said intake air temperature of air flowing through said evaporator just behind said evaporator reaches to a freezing start possible temperature defined by said intake air temperature such that the freezing of said evaporator starts, and when said preset value changing means receives said first signal, the preset value of said first physical quantity is set to a second value at which said intake air temperature reaches to a predeterminend temperature lower than said freezing start possible temperature.