Optimization of an intake manifold for an internal combustion engine

Abstract

A methodology for the optimization of an intake manifold for an internal combustion engine was proposed and tested in this research. The test bed was a 1.8L turbocharged four-cylinder Honda engine. The goal was to design, manufacture, and then test an intake manifold optimized for high rpm operation and high load conditions, those typically seen in drag racing. The runner's size and length and plenum size were first tune for operating rpms using Helmholtz equations. Due to the layout of the engine, the intake manifold is fed from the side which leads to mass flow rate inconsistencies in the cylinders. Therefore the plenum shape was optimized using computational fluid dynamics to ensure equal distribution of air to all cylinders. After the optimized design was chosen, it was manufactured from sheet metal. The engine was fitted with the stock and optimized manifolds and dyno tested on a Dynojet Chassis Dyno. At similar boost pressures, the optimized manifold made an average of 1.5 hp/psi above 5000rpm, require approximately 3 degrees less timing, and used about 4 percent less fuel, all of which are testament to the great efficiency of the optimized manifold.