In recent years, due to the adoption of more and more severe restrictions on internal combustion engines emissions, many efforts have been dedicated to the development of direct injection technology for spark ignition engines. In particular, for two-stroke engines, the adoption of DI systems is crucially important in order to reduce unburned fuel losses during the scavenging process. In this frame, the University of Perugia and Piaggio & C. established a joint research program the analyse the behaviour of the Piaggio air-assisted DI system named FAST (Fully Atomised Stratified Turbulence), currently fitted on the M164 two-stroke 50 cc engine. As a first step of this research activity, the present paper describes the results of the experimental characterisation of the steady flow obtained with the FAST system nozzle. The experimental analysis has been performed by means of a light sheet visualisation technique based on a Nd-Yag laser and a CCD camera. The off-line analysis of images pertinent to peculiar planes of the two phase flow allowed to determine its global structure at the nozzle outlet and the influences of various nozzle configurations on the flow pattern itself. Further, the influence of the combustion chamber shape and spark plug positions on the development of the two-phase flow has been investigated.

Experimental Characterization of the Flow Trough the Nozzle of a 2-Stroke Air Assisted Direct Injection System

GRIMALDI, Carlo Nazareno;POSTRIOTI, Lucio;
2000

Abstract

In recent years, due to the adoption of more and more severe restrictions on internal combustion engines emissions, many efforts have been dedicated to the development of direct injection technology for spark ignition engines. In particular, for two-stroke engines, the adoption of DI systems is crucially important in order to reduce unburned fuel losses during the scavenging process. In this frame, the University of Perugia and Piaggio & C. established a joint research program the analyse the behaviour of the Piaggio air-assisted DI system named FAST (Fully Atomised Stratified Turbulence), currently fitted on the M164 two-stroke 50 cc engine. As a first step of this research activity, the present paper describes the results of the experimental characterisation of the steady flow obtained with the FAST system nozzle. The experimental analysis has been performed by means of a light sheet visualisation technique based on a Nd-Yag laser and a CCD camera. The off-line analysis of images pertinent to peculiar planes of the two phase flow allowed to determine its global structure at the nozzle outlet and the influences of various nozzle configurations on the flow pattern itself. Further, the influence of the combustion chamber shape and spark plug positions on the development of the two-phase flow has been investigated.
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Utilizza questo identificativo per citare o creare un link a questo documento: https://hdl.handle.net/11391/924833
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