Characteristics of Homogeneous Charge Compression Ignition (HCCI) Engine Operation for Variations in Compression Ratio, Speed, and Intake Temperature While Using n-Butane as a Fuel

Abstract

In this paper, some basic properties of homogeneous charge compression ignition operation are reported. The effect of inlet temperature, compression ratio and engine speed on the homogeneous charge compression ignition (HCCI) operating ranges were evaluated in a CFR engine using n-butane as a fuel. The minimum and maximum loads for HCCI operation were determined using criteria of coefficient of variation of the indicated mean effective pressure and the derivative of in-cylinder pressure, respectively. Exhaust emissions, particularly hydrocarbons, were measured using a Fourier transform infrared spectrometer. The concentration of intermediate hydrocarbon species rapidly decreased as the magnitude of the energy release increased. Hydrocarbon emission at the maximum HCCI load mainly consists of the fuel itself, which is probably emitted from colder areas in the combustion chamber. Finally, the relationship between IMEPCOV and ISFC is discussed.