report no. 10/10

21 Dec 2010

A broad range of diesel, kerosene, and gasoline-like fuels has been tested in asingle-cylinder diesel engine optimized for advanced combustion performance.These fuels were selected in order to better understand the effects of ignitionquality, volatility, and molecular composition on engine-out emissions, performance,and noise levels. Low-level biofuel blends, both biodiesel and ethanol, wereincluded in the fuel set in order to test for short-term advantages or disadvantages.The diesel engine optimized in Part 1 of this study included practical and cumulativeengine hardware enhancements that are likely to be used to meet Euro 6 emissionslimits and beyond, in part by operating under conditions of Homogeneous ChargeCompression Ignition, at least over some portions of the speed and load map.The centre of combustion was matched for each fuel by adjusting the fuel injectiontiming. This simulates the performance of a future advanced engine operating withclosed loop combustion control using an in-cylinder pressure sensor. The warmedupengine could be run successfully on a wide range of diesel, kerosene, andgasoline-like fuels, including part-load and full-load operation, with diesel-likeefficiency.NOx emissions at or below Euro 6 emissions limits were achieved without the use ofa NOx aftertreatment system. PM emissions were also low but a diesel particulatefilter would be needed to reach Euro 6 limits and below. HC and CO emissionsincreased but were within the range that could be treated with a diesel oxidationcatalyst.Fuel properties had a substantial effect on PM emissions, consistent with the widerange of fuels investigated. In general, PM emissions decreased with increasingignition delay, higher volatility, and lower aromatics levels of the fuel but the relativeeffects varied depending upon the engine operating conditions.This study has investigated engine performance and emissions for a warmed-upsingle-cylinder bench engine only. Additional work would be needed to investigateengine performance under transient and cold start conditions.