A Trial of Engine Performance Improvement by Adopting A Turbocharger in Consideration of Intake and Exhaust Systems

摘要

The main purpose of Formula SAE competition (hereafter called "FSAE") is to let students learn the basic ability necessary for engineers through design, fabrication and test projects. In this study the authors decided to adopt Honda CBR 600 RR which was an engine for motorcycles. Then the engine have strength enough for the light weight design. As the course of the competition consists of short straights and many corners for running within equal to or less than middle speed range, the engine must have excellent acceleration performance to reduce the lap times in the corners. The effective engine performance is necessary for the flat torque in all of engine speed range, especially in low engine speed range. As the regulation allows that a turbocharger is fitted to an engine, its introduction is effective for getting high torque in the low engine speed range. In this study the authors investigate the influences of the main specifications and the characteristics of important power train components, such as turbocharger, throttle, air restrictor, air collector, intake manifold, exhaust manifold and dual system of injection, on the improvement of the engine performance by analytical methods, experiments and driving tests. The conclusions are as follows: [1] The brake torque of the engine by adopting the turbocharger in the lower range of A/R (Area of inlet port/Radius of turbine, hereafter called "A/R") has become higher in the low engine speed range. [2] In the case that the length of intake pipe is extended, the brake torque has been increased in the low engine speed range and decreased greatly in the high engine speed range.