Optimization by CFD Simulation of Spray Formation Parameters to Adapt Direct Injection High-Pressure Fuel Injectors to High-Speed SI-Engines

Abstract

<div class="htmlview paragraph">The main objective of the paper is to describe the optimization work performed to adjust direct injection (DI)-technology to SI-engines running at high (8000 to 10000 rpm.) and extremely high speeds (more than 18000 rpm). In the first category are located a certain number of small and middle displacement two-stroke series produced engines. In the second category are the typical high power racing engines used for competitions like the formula 1.</div> <div class="htmlview paragraph">The first part of the paper describes the particular requirements that an in-cylinder fuelling and mixture preparation will have to fulfill with the extremely short period available for introduction and vaporization of the fuel. The paper continues with a description of the different spray shapes, spray penetration velocities and atomization capabilities, which are optimal for the different combustion chamber architectures.</div> <div class="htmlview paragraph">The second part of the paper presents the different simulations tools used to optimize the DI-mixture preparation parameters to a small displacement two-stroke single cylinder engine and to a ten cylinder high power racing engine. Both the methodology of optimization as well as experimental engine results for both engines are presented.</div> <div class="htmlview paragraph">The paper concludes with a rating of the power/flexibility and pollutants emission capabilities of the DI-technology, when applied to high-speed SI-engines.</div>