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The purpose of this work was to investigate the influence of fuel parameters on emissions, combustion and cycle to cycle IMEP variations in a single cylinder version of a commercial direct injection stratified charge (DISC) spark ignition engine. The emission measurements employed both conventional emission measurement equipment as well as on-line gas chromatography/mass spectrometry (GC/MS). Four different fuels were compared in the study. The fuel parameters that were studied were distillation range and MTBE (Methyl Tert Buthyl Ether) content. A European certification gasoline fuel was used as a reference. The three other fuels contained 10% MTBE. The measurements were performed at a low engine speed and at a low, constant load. The engine was operated in stratified mode. The start of injection was altered 15 crankangle degrees before and after series calibration with fixed ignition timing in order to vary mixture preparation time.

The influence of ethanol content in gasoline on speciated emissions from a direct injection stratified charge (DISC) SI engine is assessed. The engine tested is a commercial DISC one that has a wall guided combustion system. The emissions were analyzed using both Fourier transform infrared (FTIR) spectroscopy and conventional emission measurement equipment. Seven fuels were compared in the study. The first range of fuels was of alkylate type, designed to have 0, 5, 10 and 15 % ethanol in gasoline without changing the evaporation curve. European emissions certification fuel was tested, with and without 5 % ethanol, and finally a specially blended high volatility gasoline was also tested. The measurements were conducted at part-load, where the combustion is in stratified mode. The engine used a series engine control unit (ECU) that regulated the fuel injection, ignition and exhaust gas recirculation (EGR).

Reducing emissions and improving efficiency are major goals of modern internal combustion engine research. The use of biomass-derived fuels in Diesel engines is an effective way of reducing well-to-wheels (WTW) greenhouse gas (GHG) emissions. Moreover, partially premixed combustion (PPC) makes it possible to achieve very efficient combustion with low emissions of soot and NOx. The objective of this study was to investigate the effect of using alcohol/Diesel blends or neat alcohols on emissions and thermal efficiency during PPC. Four alcohols were evaluated: n-butanol, isobutanol, n-octanol, and 2-ethylhexanol. The alcohols were blended with fossil Diesel fuel to produce mixtures with low cetane numbers (26-36) suitable for PPC. The blends were then tested in a single cylinder light duty (LD) engine. To optimize combustion, the exhaust gas recirculation (EGR) level, lambda, and injection strategy were tuned.

The purpose of this paper is to assess the influence of fuel properties on cycle-resolved exhaust hydrocarbons and investigate the sources of hydrocarbon (HC) emissions in a direct injection stratified charge (DISC) SI engine. The tested engine is a single cylinder version of a commercial DISC engine that uses a wall guided combustion system. The HC emissions were analyzed using both a fast flame ionization detector (Fast FID) and conventional emission measurement equipment. Three fuels were compared in the study: iso-Pentane, iso-Octane and a gasoline of Japanese specification. The measurements were conducted at part-load, where the combustion is in stratified mode. The start of injection (SOI) was altered in relation to the series calibration to vary the mixture preparation time, the time from SOI to ignition. The ignition timing was set at maximum brake torque (MBT) for each test.