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A prototype multipoint fuel injection system which utilises fluidic injection devices as fuel injectors for spark ignition engines is described in this paper. The unique fluidic injector unit combines four no-moving-part, monostable fluidic devices controlled by a solenoid valve interface and air-fuel mixing nozzles for well atomised air-fuel mixture. The design philosophy and operating characteristics of the novel integrated fluidic injector unit for engine applications are discussed in details in this paper. The initial engine tests on this fluidic injection system show that it provides an extended lean limit of the air/fuel mixture (by 2.2 air/fuel ratio), 7% improvement in fuel economy and 10% reduction in HC emissions compared with a base line carburetted system. These results confirmed that the use of the fluidic fuel injection system resulted in improved fuel distribution, better air/fuel mixture preparation and faster flame propagation speed.

This paper describes a gasoline injection system based on air-assisted fluidic injectors. This injection system was implemented on a research engine and the results of air to fuel ratio (AFR) variations, engine combustion characteristics and exhaust emissions from the fluidic injector unit were compared with those from the baseline solenoid type injector. It was demonstrated that the fluidic system produces 9% to 20% lower HC emissions and 5% to 8% higher IMEP than the baseline injection system. This has confirmed the effectiveness of the use of the air-assisted fluidic injector stages and that the improved mixture preparation fuel presentation are obtained by the fluidic system. However, the cyclic flow stability of the fluidic device needs improvement.