An automotive engine charge-air intake conditioner system: analysis of fuel economy benefits in a gasoline engine application

A combination of analytical techniques has been used to quantify the potential fuel economy benefits of an automotive engine charge-air intake conditioner system applied to a spark-ignited gasoline engine. This system employs a compressor, intercooler, and expander to provide increased charge density with the possibility of reducing charge-air temperature below sink temperature. This reduction in charge-air temperature provides the potential for improved knock resistance at full load; thereby allowing the possibility of increasing compression ratio with corresponding benefits in thermodynamic cycle efficiency and part-load fuel economy. The four linked and interfaced models comprised a first-law thermodynamic model of the charge-air conditioner system, a one-dimensional engine cycle simulation, a two-zone combustion model, and a knock criterion model. An analysis was carried out under full load at 3000 r/min and showed that a charge-air conditioner system - with compressor, intercooler, and expander efficiencies of 0.8 - allowed the compression ratio to be increased by approximately half a ratio, which gave up to 1.5 per cent reduction in brake specific fuel consumption at 2000 r/min 2 bar brake mean effective pressure when compared with a conventional pressure charger intercooler system with no expander

An automotive engine charge-air intake conditioner system: thermodynamic analysis of performance characteristics

A first law thermodynamic model has been developed and used to characterize the performance of an automotive engine charge-air intake conditioner system. This system employs a compressor, intercooler, and expander to provide increased charge density with the possibility of reducing, the charge-air temperature below the sink temperature. The model was validated against experimental measurements. The variation of system effectiveness with compressor, intercooler, and expander efficiency was quantified and system operating limits were identified. While the expander was found to have a greater effect than the compressor, the performance of the system was shown to be most dependent upon intercooler effectiveness