Optimized cooling for vehicle with start-stop technology

摘要

An air conditioning system for a start-stop vehicle employs a compressor with a variable displacement. A controller determines a normal Climate Thermal Load (CTL) value for controlling a variable stroke of the variable displacement compressor. A stop event is detected in response to a speed of the vehicle and the occurrence of a predetermined deceleration. During the stop event, the variable stroke is increased by an amount determined in response to the normal CTL value, the speed of the vehicle, and a measure of the deceleration of the vehicle so that an evaporator temperature within the air conditioning system is allowed to decrease while the vehicle is stopping so that climate comfort can be maintained even while the engine is shut off during the subsequent time that the vehicle is stopped.

主权项

1. A vehicular air conditioning system for a vehicle having a start-stop technology, comprising:
an evaporator; an evaporator temperature sensor for generating an evaporator temperature signal according to a temperature of the evaporator; an exterior temperature sensor for generating an exterior temperature signal according to a temperature outside of the vehicle; an occupant control element for setting an occupant demand signal; a variable displacement compressor driven by the engine and having a variable stroke for generating a variable amount of cooling of the evaporator in response to a stroke control signal; a vehicle speed sensor generating a speed signal according to an instantaneous speed of the vehicle; and a controller configured to receive the evaporator temperature signal and the speed signal, the controller 1) configured to determine a Climate Thermal Load (CTL) value in response to the exterior temperature signal and the occupant demand signal, 2) configured to determine an evaporator target temperature in response to the CTL value, 3) configured to vary the variable stroke to keep the evaporator temperature signal near the evaporator target temperature, 4) configured to detect a stop event of the vehicle in response to the speed signal being less than or equal to a threshold speed and the occurrence of a deceleration, and 5) configured to determine the evaporator target temperature during the stop event in response to a modified CTL value determined in response to the CTL value, the speed signal, and a magnitude of the deceleration.