Study of Inlet Air Parameter Effects on Variation of Peak Cylinder Bulk Temperature of Compression-Ignition Engine

摘要

The work of this paper investigates the variation of peak cylinder bulk temperature (T_(max)) versus inlet air parameters of compression-ignition engines. A simplified analytical model, for understanding and predicting the variation of the temperature (ΔT_(max)) due to varying engine inlet air temperature (T_i), pressure (p_i) or intake manifold air temperature (T_m) from a respective reference state, is established. The effects of varying the parameters on ΔT_(max) for both naturally aspirated and turbocharged engines are analyzed and evaluated. The predicted results are presented and compared with some available turbocharged diesel engine experimental determinations. The design and operation input parameters interesting or significant in influencing ΔT_(max) along with varying T_i, p_i or T_m are also investigated. Those parameters include the degree of engine cylinder compression, the intake manifold to inlet air temperature and pressure ratios, and combustion-heat mean effective pressure Q_(mep) which indicates the level of the combustion heat input to the engine cylinder. As one of those parameters increases, the rate of ΔT_(max) following varying T_i or p_i will become larger. A corresponding change of T_(max) versus intake manifold air T_m is also considered and evaluated as T_m varies independently or dependently upon T_i and p_i of a turbocharged inter-cooled engine.