INFLUENCE OF VARIABLE COMPRESSION RATIO ON EMISSION AND VIBE FUNCTION PARAMETERS OF EXPERIMENTAL ENGINE

Abstract

Compression ratio as a constructive parameter has a very important influence on fuel economy, emission and other performances of internal combustion engines. Introduction of variable compression ratio has the number of benefits: limiting maximal in-cylinder pressure, extended field of the optimal operating regime with minimal fuel consumption, more power, reduced exhaust emission and controlled noise emission. It is particularly characteristic for multifuel capability of engines with variable compression ratio (VCR), along the control of maximum temperature and pressure in the cylinders. The paper presents engines and mechanisms for automatic change of compression ratio value. Modelling of operation process of internal combustion (Otto and Diesel) engines with direct injection has been performed in parallel with experimental research. The basic problem is the selection of the parameters in double Vibe function used for modelling of the diesel engine operation process, also performed for different compression ratio. The optimal compression ratio value was defined regarding the minimal fuel consumption and exhaust emission. For this purpose, the test bench is brought into operation in the Laboratory for Engines of the Faculty of Engineering, University of Kragujevac.