Abstract
There are many solutions developed to improve the cold startability of diesel’s engines. This paper presents results from numerical simulation of the air flow in Compression Ignition Engine (CI engine) cylinder and also the investigation of an injection of diethyl ether module used to improve the cold starting of a diesel engine at the low temperature. The most usual numerical method in Computational Fluid Dynamics (CFD) is finite volume. In this investigation an important common fluid flow patterns in CFD simulations, namely, swirl motion typical in automotive engines and RNG k-e turbulence model were used. A three-dimensional unsteady turbulent compressible FLUENT solver was utilized in the present study to investigate the intake injection method of a four-valve direct injection compression ignition engine. The intake process is complicated considering the gas dynamics of the intake manifold when the walls of the intake system and cylinders are cold, a much smaller percentage of the fuel will vaporize than in normal steady-state operation. The engine turns very slowly, being driven only by the starting motor, and a greater amount of the compressive heating during compression is lost by heat transfer to the cold walls. This is made worse by the cold viscous lubricating oil that resists motion and slows the starting speed even more. All of these factors contribute to the need for a very rich air-fuel ratio when starting a cold engine. DEE (diethyl ether) was inducted as an ignition improver through the intake manifold. Results of these simulations aid in the improved understanding of the intake process and its influence on direct injection compression.
Keywords: DEE, Flow Field, Intake Manifold, Evaporation, CFD, Cold Start