Effect of Hydrogen Addition on Cyclic Variations in Homogeneously Charged Compression-Ignition Engines

摘要

The operation of homogeneously charged compression-ignition (HCCI) engines at low loads often suffer from excessive cyclic variations since the homogeneous charge is too fuel-lean to burn completely. The paper describes the results of an analytical approach that models in full the reaction rate development when hydrogen is added to a naturally aspirated, methane or propane fuelled motored HCCI engine. The operating conditions at which these effects are examined are those that are conducive to the onset of cyclic variations, such as fuel-lean conditions and low volumetric efficiencies. It is shown that the addition of hydrogen, which has a relatively wide operating range, to a methane- or propane-fuelled engine can reduce cyclic variations while extending the operating region of the engine.