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Comparison of particulate size distribution measurements from different combustion strategies was conducted with a four-stroke single-cylinder diesel engine. Measurements were performed at four different load-speed points with matched combustion phasing. Particle size distributions were measured using a scanning mobility particle sizer (SMPS). To study the influence of volatile particles, measurements were performed with and without a volatile particle remover (thermodenuder) at low and high dilution ratios. The use of a single testing platform enables quantitative comparison between combustion strategies since background sources of particulate are held constant. A large number of volatile particles were present under low dilution ratio sample conditions for most of the operating conditions. To avoid the impact of volatile particles, comparisons were made based on the high dilution ratio measurements with the thermodenuder.

The effect of fuel physical properties on the ignition and combustion characteristics of diesel fuels was investigated in a heavy-duty 2.52 L single-cylinder engine. Two binary component fuels, one comprised of farnesane (FAR) and 2,2,4,4,6,8,8-heptamethylnonane (HMN), and another comprised of primary reference fuels (PRF) for the octane rating scale (i.e. n-heptane and 2,2,4-trimethylpentane), were blended to match the cetane number (CN) of a 45 CN diesel fuel. The binary mixtures were used neat, and blended at 25, 50, and 75% by volume with the baseline diesel. Ignition delay (ID) for each blend was measured under identical operating conditions. A single injection was used, with injection timing varied from −12.5 to 2.5 CAD. Injection pressures of 50, 100, and 150 MPa were tested. Observed IDs were consistent with previous work done under similar conditions with diesel fuels. The shortest IDs were seen at injection timings of −7.5 CAD.

The effects of jet fuel properties on compression ignition engine operation were investigated under high-load conditions for jet fuels with varying cetane number. A single-cylinder oil-test engine (SCOTE) with 2.44 L displacement was used to test a baseline #2 diesel fuel with a cetane number of 43, a Jet-A fuel with a cetane number of 47, and two mixtures of Jet-A and a Fishcer-Tropsch JP-8 with cetane numbers of 36 and 42, respectively. The engine was operated under high-load conditions corresponding to traditional diesel combustion, using a single injection of fuel near TDC. The fuels were tested using two different intake camshafts with closing times of -143 and -85 CAD BTDC. Injection timing sweeps were performed over a range of injection timings near TDC for each camshaft. The apparent net heat release rate (AHRR) data showed an increase in the premixed burn magnitude as cetane number decreased in agreement with previous work.

The Diesel Exhaust Filtration Analysis System (DEFA) developed at the University of Wisconsin Madison was modified to perform fundamental filtration experiments using particulate matter (PM) generated by a spark-ignition direct-injection (SIDI) engine fueled with gasoline. The newly modified system, termed the Exhaust Filtration Analysis (EFA) system, enables small-scale fundamental studies of wall-flow filtration processes. A scanning mobility particle sizer (SMPS) was used to characterize running conditions with unique particle size distributions (PSDs). The SMPS and an engine exhaust particle sizer (EEPS) were used to simultaneously measure the PSD downstream of the EFA and the real-time particulate emissions from the SIDI engine, to determine the evolution of filtration efficiency during filter loading. Corrections were developed for each running condition to compare measured PSDs between the EEPS and the SMPS in the raw, as well as, filtered exhaust stream.