Method of controlling refrigeration system for automotive air conditioner

A method of controlling a refrigeration system for an automotive air conditioner, said system including a variable displacement refrigerant compressor and an evaporator, said method including:

• detecting a condition related to the cooling operation of said evaporator to obtain a first signal;
• detecting the ambient temperature outside an occupant compartment of the automobile to obtain a second signal;
• when said second signal is at a level greater than said predetermined level, causing said compressor to one of be operative at a large displacement capacity, be operative at a small displacement capacity and be inoperative in accordance with said first signal;
• and
• when said second signal is decreased to a level less than said predetermined level, causing said compressor to one of be operative at a small displacement capacity and be inoperative in accordance with said first signal.

A method of controlling a refrigeration system for an automotive air conditioner, said system including a variable displacement refrigerant compressor adapted to be driven by an engine of the automobile and an evaporator, said method including:

• detecting a condition related to the cooling operation of said evaporator to obtain a first signal;
• detecting a temperature of an ambient air outside an occupant compartment of the automobile to obtain a second signal;
• detecting the operation speed of said engine to obtain a third signal;
• and
• utilizing said first, second and third signals to control the compressor operation such that the displacement capacity of said compressor is varied stepwise and said compressor is operated intermettently.