The Impact of Fuel Injection Timing and Charge Dilution Rate on Low Temperature Combustion in a Compression Ignition Engine

Using high charge dilution low temperature combustion (LTC) strategies in a diesel engine offers emissions of nitrogen oxides (NOx). These are limited to part-load conditions and involve levels dilution, typically achieved through the use recirculated exhaust gases (EGR). The slow response gas handling system, compared load demand fuelling, can lead where higher or lower than expected, impacting stability. This article reports on sensitivity high-dilution LTC variations EGR rate fuel injection timing. Impacts efficiency, stability assessed single-cylinder in-cylinder flame temperatures measured using borescope-based two-colour pyrometer. work focuses low-load (300 kPa gross indicated mean effective pressure) includes an sweep from conventional mode LTC, studies investigating effects timing at condition. Key findings study include that peak decreased ~2580 K with no 1800 low-NOx, low-soot operation 57%. Increasing 64% reduced 1400 but increased total hydrocarbon (THC) carbon monoxide (CO) by 30–50% consumption 5–7%. Charge was found have stronger effect process under these conditions. Advancing timings increasing kept instability below 2.5%. Peak were maintained 2000–2100 range, while THC CO controlled delaying onset bulk quenching. Very early (earlier 24 °CA before top-dead-centre) resulted spray impingement piston crown, resulting degraded efficiency emissions. results this demonstrate potential modification accommodate rates maintaining NOx PM low-temperature part loads.