Experimental and numerical study of a spark ignition engine with air-assisted direct injection

Boretti, Alberto, Jin, Seong-Ho, Brear, Michael , Zakis, George, Watson, Harry and Brewster, Simon (2008) Experimental and numerical study of a spark ignition engine with air-assisted direct injection. Proceedings of the IMechE, Part D: Automobile Engineering, 222 (6). pp. 1103-1119. ISSN 0954-4070

Full content URL: http://dx.doi.org/10.1243/09544070JAUTO712

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Abstract

An experimental and numerical study of the spray from an air-assisted fuel injector in a direct-injection spark ignition (DISI) engine is presented. The experiments are performed using ultraviolet laser diagnostics in a motoring optical engine that is a DISI variant of a production port-fuel-injected engine. Non-optical single-cylinder firing engine results of experiments and simulations are also presented. Recent related work by the present authors has shown that, under design conditions, the air-assisted injector exhibits strong coupling between the liquid and gas phases. It results in a filled-in conical spray of relatively fine atomization and low penetration, with liquid and vapour fuel concentrations close to the centrally located injector and spark plug, as required for lean stratified operation. This paper shows the strong effect of increasing the chamber temperature on spray evaporation and penetration. This observed temperature effect shows that spray evaporation should vary significantly during cold start. Exhaust gas recirculation (EGR) may also have a beneficial effect on DISI engine performance through enhanced spray evaporation, although this is difficult to verify experimentally. If true, this effect of EGR is a separate mechanism to the known beneficial effects of EGR in air-assisted DISI engines.

Keywords:spark ignition engine, air-assisted direct injection, experiments, simulations, bmjdoi, Digitised
Subjects:H Engineering > H141 Fluid Mechanics
H Engineering > H330 Automotive Engineering
H Engineering > H311 Thermodynamics
Divisions:College of Science > School of Engineering
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ID Code:4607
Deposited On:20 Aug 2011 08:06

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