engleski

Characterisation of the Combustion Process in the Spark Ignition and HCCI Engine Fuelled With Methane

Homogeneous Charge Compression Ignition (HCCI) engine is a potential solution for reducing air pollution and for satisfying legal limits of permissible emissions from internal combustion engines (ICE). Combustion process in HCCI engine is a form of Low Temperature Combustion (LTC) that has a potential of achieving high efficiencies. HCCI engines have advantages of lower emissions of nitrogen oxides (NOX) and particulate matter (PM), compared to standard combustion modes, but on the other hand one of the major disadvantages is the fact that it is relatively difficult to control a start of combustion because it is highly sensitive to the intake air temperature. Additionally advantage of the HCCI engine is the ability to operate with variety of fuels. Therefore in this study HCCI engine is powered by methane. The aim of the study is to characterise and compare two different combustion modes on the same engine at similar operating conditions. To perform such characterisation the engine tests are performed at the same indicated mean effective pressures (IMEP) for the spark ignition (SI) and HCCI combustion mode at the same engine speed. Load for the HCCI engine was adjusted by setting the appropriate air to fuel ratio while for the SI engine, predefined load (IMEP) was obtained by changing the intake air pressure. The tests are performed at three different speeds and three different levels of IMEP on the experimental setup built in the Laboratory for IC Engines and Motor Vehicles at the Faculty of Mechanical Engineering and Naval Architecture. The setup consists of modified single cylinder diesel engine Hatz 1D81Z and the modifications have enabled operation in SI and in HCCI mode. The characterisation includes the comparison of in-cylinder pressures, temperatures and rate of heat release (ROHR) obtained by SI and HCCI combustion mode. It also presents comparisons of the emissions of HC, CO, CO2 and NOX, and in the end the comparison of engine efficiencies together with the comparison of engine control will be shown.

SI engine, HCCI engine, methane, experimental engine testing

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