Modeling of internal combustion engine thermodynamics, valve dynamics and valve flow

[摘要] ENGLISH ABSTRACT:In the design or modification of internal combustion (IC) enginecomponents, the South African Automotive industry has always relied oneither design by mother companies or quasi-empirical design methods.These methods have restricted the performance and reliability of localdesigns.A personal computer based model of four stroke engine operation hasbeen developed as a rapid and cost-effective aid to users who wish todetermine the performance of an engine with reasonable accuracy beforedynamometer testing is possible. This model consists of a thermodynamicmodel of combustion and gas exchange linked to a manifold flow model.Accompanying this is a simulation of valve flow and a cam dynamic model,enabling full assessment of the optimum cam profiles and valve angles forvarious automotive engine configurations.The accuracy of these models has been verified by comparison with a setof engine dynamometer tests. The models have also been used with greatsuccess in local and international development projects in conjunction withlocal automotive manufacturers. In particular, two engine upgrade projectshave been successfully completed, in which the program was used to aidthe design of inlet manifolds, the selection of camshafts, and the selectionof compression ratios.

[发布机构] Stellenbosch University