An Attempt to Improve the Characteristics of Volumetric Efficiency by a Resonator in Four Cycle Diesel Engines : Heat Transfer, Combustion, Power, Thermophysical Properties

Abstract

Through numerical calculations based on a simulation program, the effect of a resonator, which is installed in intake manifolds, has been investigated for the purpose of improving the volumetric efficiency of four cycle diesel engines. The results show that in single cylinder engines a resonator can increase the volumetric efficiency at low engine speeds without decreasing volumetric efficiency in the high speed range. The diameter of the resonator pipe must be chosen to generate an adequate flow loss in the resonator. The optimum sizes of the resonator can not be estimated simply by the natural acoustic frequency. However, the ratio of the natural frequency of the resonator to that of the intake system for the open period of the intake valve may be used to estimate roughly the resonator effect. The resonator effect is considered to be slight in multi-cylinder engines.