Operating a Heavy-Duty Direct-Injection Compression-Ignition Engine with Gasoline for Low Emissions

Abstract

<div class="htmlview paragraph">A study of partially premixed combustion (PPC) with non-oxygenated 91 pump octane number<sup><span class="xref">1</span></sup> (PON) commercially available gasoline was performed using a heavy-duty (HD) compression-ignition (CI) 2.44 l Caterpillar 3401E single-cylinder oil test engine (SCOTE). The experimental conditions selected were a net indicated mean effective pressure (IMEP) of 11.5 bar, an engine speed of 1300 rev/min, an intake temperature of 40°C with intake and exhaust pressures of 200 and 207 kPa, respectively. The baseline case for all studies presented had 0% exhaust gas recirculation (EGR), used a dual injection strategy a -137 deg ATDC pilot SOI and a -6 deg ATDC main start-of-injection (SOI) timing with a 30/70% pilot/main fuel split for a total of 5.3 kg/h fueling (equating to approximately 50% load).</div> <div class="htmlview paragraph">Combustion and emissions characteristics were explored relative to the baseline case by sweeping main and pilot SOI timings, injection split fuel percentage, intake pressure, load and EGR levels.</div> <div class="htmlview paragraph">The results from these tests produced low engine-out NOx and PM emissions. Interestingly, with EGR rates over 20%, both NOx and PM were simultaneously reduced while maintaining or even lowering indicated specific fuel consumption (ISFC).</div> <div class="htmlview paragraph">The results presented in this paper demonstrate promising in-cylinder emissions reductions from the use of gasoline in HD CI engines.</div>