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Cycle-to-cycle variations of a diesel engine operating with palm biodiesel

Yasin M. H., Mamat R., Abdullah A. A., Abdullah N. R., Wyszynski M. L.

Journal of KONES

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2013

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Vol. 20, No. 3

443--450

EN

Biodiesel is one of biodegradable and renewable fuel, which is originated from vegetable oil or animal fats. Different fuel properties of biodiesel produce different combustion characteristics which slightly differ to mineral diesel. Combustion studies on palm-biodiesel and mineral diesel were conducted using a multi-cylinder diesel engine operating at medium engine load at 2500 rpm. The engine was water cooled inline four cylinder diesel engines without exhaust gas recirculation system. Cycle-to-cycle variations of peak cylinder pressure and mean indicated pressure of the test fuels were determined for the combustion characteristics of diesel engine. In-cylinder pressure data for the 200 consecutive cycles were determined using a Kistler pressure transducer and recorded into a combustion analyser. Three different engine loads: 20%, 40% and 60% were selected in this study with a constant engine speed of 2500 rpm. The results show that at lower load, in-cylinder pressure variations for palm biodiesel were lower compared to mineral diesel. However, at medium and high loads, palm biodiesel has dominated the peak cylinder variations. Different combustion cyclic variations for mineral diesel and B100 are observed and generally influenced by psychochemical properties differences including viscosity and density of fuel.

2

Combined Effects of Pilot Quantity, Injection Pressure and Dwell Periods on the Combustion and Emissions Behaviour of a Modern V6 Diesel Engine

Abdullah N. R., Wyszynski M. L., Tsolakis A., Mamat R., Xu H. M., Tian G.

Archivum Combustionis

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2010

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Vol. 30 nr 4

481-495

EN

Experimental results have shown that high exhaust emissions in diesel engines can be avoided by employing special injection strategies. This is because an increased homogeneity of the fuel-air mixture created by some injection strategies has a capability to improve NOx-PM trade-off. Therefore, the mixture quality is a primary parameter that needs to be controlled in order to enhance engine power output and low exhaust emissions. In fact, the combustion strategy employing multiple injections and EGR technique tends to introduce better fuel economy as well. In the experimental work presented in this paper the combinations of pilot quantities, injection pressures and dwell periods (time lapse between Pilot Injection Timing and Main Injection Timing) have been tested on a modern V6 diesel engine. The engine utilises a common rail direct injection, is fitted with twin turbo-charged variable turbine geometry (VTG) turbochargers and is fuelled with ultra low sulphur diesel (ULSD). The overall results show that these strategies have a potential to improve exhaust emissions specifically NOx, Particulate Matter, THCs, CO emissions and fuel economy.

3

The effect of injection pressure and strategy in a Jaguar V6 diesel engine

Abdullah N. R., Mamat R., Rounce P., Wyszynski M. L., Tsolakis A., Xu H. M., Tian G.

Journal of KONES

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2009

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Vol. 16, No. 2

9-22

EN

In recent years, the improvement of engine performance and emissions has become an extremely important concern. This study focuses on the injection strategy based on the injection pressure (IP) and duration between pilot injection and the main injection (dMI) using a multi cylinder common rail multiple injections diesel engine. The study was designed to produce improvements in fuel mixing via the injection strategy, to reduce the main ignition delay. This would contribute to a minimum amount of fuel burnt in the premixed combustion phase, leading to a reduction in emissions. Recent evidence shows that premixed combustion is significant in the controlling of emissions of nitrogen oxides (NOx) and soot. Six different IPs combined with a short and long dMI were compared in the attempt to improve engine performance and emissions. The engine performance was measured in terms of brake specific fuel consumption, ignition delay, heat release and peak in-cylinder pressure and emissions, specifically nitrogen oxides (NOx), total unburned hydrocarbons (THC), carbon monoxide (CO) and smoke emissions for each engine test condition. The evidence from this study shows that the effect of IP is more dominant than dMI in terms of peak cylinder pressure, heat release, brake specific fuel consumption and emissions. However, the dMI shows a strong effect at a higher engine speed.