MODELING AND ANALYSIS OF VARIABLE GEOMETRY EXHAUST MANIFOLD SYSTEM TO IMPROVE TRANSIENT ENGINE OPERATION OF A LOW SPEED DIESEL ENGINE

Abstract

The aim of this research work is to verify the engine transient newlinesimulation of a multicylinder diesel engine with improved overall newlineperformance. Simulation of internal combustion engine has become very newlineimportant in recent days due to the availability of increasing computer power newlineand computer simulation software. A modern computer simulation model is newlineused to compare overall efficiency and volumetric efficiency with newlineinstantaneous values. A baseline engine model is first correlated with newlinemeasured efficiency data to establish confidence in the engine model s newlinepredictions. A derivative of the baseline model, complete with a newly newlinedeveloped exhaust manifold, is then subjected to a transient excursion newlinesimulating typical, in-service, maximum rates of engine speed change. The newlineexhaust manifold system in the multicylinder diesel engine contributes for the newlinebetter breathing of the engine and optimum engine cylinder charging. newlineInstantaneous volumetric efficiency, calculated over discrete engine cycles newlineforming the sequence, is then compared with its steady speed counterpart at newlinethe corresponding speed. The computer simulation model is used to newlinedemonstrate the optimized design and performance of the baseline engine. newlineThe research work provides a good example of the application of computer newlinesimulation techniques in providing answers to real engineering questions newlinemainly on the flow characteristic phenomena of the manifold flow pipes newlineunder transient engine conditions. The objective of modified geometry newlineexhaust manifold is to identify the maximum possible flow through the newlineexhaust pipes and to find the optimal flow rates across the pipe junctions. newlineThe developed design of Y shaped exhaust manifold improves newlinetransient performance of a four cylinder diesel engine and from the study it is newlineobserved that the torque during a load transient evolution is directly newlinecontrolled by the air mass flow rate and load transient tests at different engine newlinespeed are performed with dissimilar manifolds. Design and newlineoperational variables of inlet and exhaust system