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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.

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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.

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Investigation into particulate size distributions in the exhaust gas of diesel engines fuelled with biodiesel blends

Chuepeng S., Theinnoi K., Xu H. M., Wyszynski M. L., York A. P. E., Hartland J. C., Qiao J.

Journal of KONES

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2008

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Vol. 15, No. 3

75-82

EN

Particulate matter (PM) size distributions in the exhaust gas of biodiesel blend fuelled diesel engines have been studied by experimenting firstly on a single cylinder equipped with a pump-line-injector injection system and secondly for comparison on a V6 DI engine equipped with a common rail fuel injection system. Both engines were operated with a biodiesel (RME) blend of B30 and ultra low sulphur diesel fuel (ULSD). Several engine load conditions with and without exhaust gas recirculation (EGR) were selected. Particulate number concentrations vs. the electrical mobility equivalent diameter were examined using a fast differential mobility spectrometer. The effect of engine operating conditions including EGR rates on particulate emissions has been investigated. It is found that PM sizes from combustion of B30 without EGR operation are generally smaller than those from ULSD while number concentrations are higher. This can result in lower PM mass estimates for the B30 case if due care is not taken. When EGR is applied to control nitrogen oxides emissions, both the total PM number and mass are increased and shifted toward the larger sizes for both fuels used in the test. The calculated total PM mass from B30 combustion is lower than in the ULSD case for all the tested engine operating conditions.