Characterisation of ignition delay period for a compression ignition engine operating on blended mixtures of diesel and gasoline

• Published in: Applied thermal engineering Vol. 66; no. 1-2; pp. 55 - 64
• Main Authors: Thoo, Wei Jet, Kevric, Arman, Ng, Hoon Kiat, Gan, Suyin, Shayler, Paul, La Rocca, Antonino
• Format: Journal Article
• Language: English
• Published: Kidlington Elsevier Ltd 01.05.2014; Elsevier
• Subjects: Applied sciences; Blends; Chemical kinetic mechanism; Combustion; Crude oil, natural gas and petroleum products; Delay; Diesel; Diesel engine; Diesel engines; Diesel–gasoline blends; Energy; Energy. Thermal use of fuels; Engines and turbines; Equipments for energy generation and conversion: thermal, electrical, mechanical energy, etc; Exact sciences and technology; Fuels; Gasoline; Heat transfer; Ignition; Ignition delay; Petroleum products, gas and fuels. Motor fuels, lubricants and asphalts; Polymer blends; Theoretical studies. Data and constants. Metering; Diesel engine; Diesel–gasoline blends; Chemical kinetic mechanism; Ignition delay; Diesel fuel; Gasoline; Compression ignition engine; Diesel―gasoline blends; Mixture
• ISSN: 1359-4311
• DOI: 10.1016/j.applthermaleng.2014.01.066

The widely different autoignition characteristics of diesel and gasoline has been exploited in blends of varying proportion here to investigate the influence on ignition delay (ID) and in turn, charge preparation, heat release and injection timing requirements for the best combustion phasing in a compression ignition engine. Experimental studies have been carried out on a light-duty turbocharged direct-injection diesel engine with pump injection system to test diesel–gasoline fuel blends comprising up to 80%vol. gasoline. ID increases with the gasoline content of the blend, and generally gives rise to an increase in the premixed heat release. The duration of combustion is not markedly changed. Higher gasoline blends retarded the start of fuel injection by up to 3° crank angle (CA) due to changes in physical properties. The change in injection timing affected combustion phasing but not ID directly. The contribution of chemical delay to ID has been investigated using CHEMKIN. The increases in ID period and premixed combustion heat-release rate associated with higher gasoline blend fractions are found to be caused by the chemical delay. Physical delay is less dependent on blend proportions and more dependent on engine operating condition, which increases with higher engine speed and intake boost pressure. •The feasibility of using gasoline in DI-CI engine is investigated.•Ignition delay and heat release rate are the main parameters of interest.•The potential to simultaneously reduce both soot and NOx is shown.•Higher gasoline blend fractions increase the chemical delay period.•Physical delay period is more dependent on engine operating conditions.