F2010A030
DEVELOPMENT OF FUEL CONSUMPTION REDUCING CONTROL ALGORITHMS DURING ACCELERATION AND DECELERATION FOR THE AUTOMOTIVE AIR CONDITIONING SYSTEM WITH AN EXTERNAL VARIABLE COMPRESSOR
Keywords: External variable displacement compressor, Cooperative control PT-AC , Control algorithm, Fuel consumption, ECV duty
Abstract : Due to the public interest in environmental conservation in recent years, the automobile industry now requires technological innovations to reduce fuel consumption. Innovative technologies demand that the air-conditioning system be of "a power-saving design", which would reduce the engines emissions. In regulatory testing, the US EPA has included air conditioning operation as part of the Supplemental Federal Test Procedure (SFTP) known as the SC03. With these new requirements, enhanced compressor control is essential to power saving. With this in mind, the variable displacement compressor is more advantageous than other types. This paper describes the power saving air-conditioning control algorithms through cooperative control PT-AC with an externally controlled compressor. Coordinating A/C system with the powertrain, the algorithms reduce compressor displacement during vehicle acceleration to prevent excessive A/C cooling for power saving, and increase the compressor displacement to store the cool air during deceleration which will improve fuel consumption when driving. The power saving compressor control algorithms which do not affect passenger comfort is the main focus of this paper. The compressor variable displacement control for reduction of fuel consumption needs various signal selections and a domain definition which can judge the vehicle's driving condition whether accelerating or decelerating. To maximize power saving and reduction of fuel consumption, a careful consideration and application for allowable widening range of target temperature of evaporator air outlet is essential to achieve this goal (the highest comfort temperature in acceleration and the lowest temperature in deceleration). The test vehicle prototype is operational and undergoing validation thermal comfort and drivability. These evaluations include climatic wind tunnel testing and field testing. Fuel consumption with the air conditioning operating has been tested through measurement of the fuel usage and the compressor torque. A 4.5% potential reduction in SC03 and a 2.35% improvement of fuel efficiency in the real road city driving were found and acceleration performance was also improved by about 1%.
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