The Cooling Effect of Compressed Natural Gas Throttling on Engine Inlet Air Temperature and Fuel Metering

摘要

A theoretical study was conducted to investigate the cooling effect of throttling compressed natural gas during the pressure regulation process. The concept of using this effect in cooling down the induction air was investigated. A thermodynamic model was develoepd for a typical fuel delivery system used on a vehicle operating with compressed natural gas. The model was based on a set of integral conservation laws applied to each component in the system. Several heat exchanging arrangements between the throttled gas and the inlet air were examined. The effect of the added heat exchanger on engine performance and fuel metering was examined for different engine sizes as well as for different operating conditions. An increase of 1 to 2.5percent in engine power was predicted dut to the added heat exchanger. More work is needed to optimize and implement the proposed concept.