Intake system design procedure for engines with special requirements

Abstract

Intake manifolds provide fresh air to internal combustion engines and have a major effect on their performance. Therefore, many investigations are related to their design in order to improve the charging efficiency and to achieve the uniform distribution of fresh air among the engine cylinders. This paper deals with the design procedure of a cheap multipoint injection intake system, adapted to a racing car engine. Some special demands had to be taken into consideration. The intake manifold must contain the imposed constraint for the airflow in the shape of a single circular restrictor placed between the throttle and the engine to limit its power. The flow and the pressure loss reduction in the engine intake region were investigated with computational fluid dynamics software. Two different geometries of the intake manifold were taken into consideration. On the basis of the numerically obtained three-dimensional results, a mathematical model of the engine with a more appropriate intake was made in the engine simulation code in order to anticipate its characteristics. The intake system was designed, practically manufactured, and tested in the laboratory. The experimental results confirmed numerical predictions, justifying the simple and relatively quick design procedure for the intake system.