First Test Results of a 1-Cylinder Engine with Variable Compression Ratio, Fully Mechanically Variable Inlet and Exhaust Valve Actuation

A 1-cylinder experimental engine with a mechanically fully variable valve train (CVVL) on inlet-and exhaust camshaft and an additional fully variable compression ratio was investigated on a test bed at the Technical University of Kaiserslautern. Up so far only an electro mechanical valve train with similar high valve curve variability has been tested under research conditions. In this paper, the first test results at part load with throttle-free load control are here compared with the results of a 4-cylinder engine. The influence of the charge-cycle-work and the residual gas content concerning fuel consumption is analyzed. Variabilities of the exhaust camshaft, such as the exhaust valve spread phasing for example, are simulated with CFD-methods. Furthermore the influences on fuel consumption and NOx-emissions of the exhaust valve lift height and the duration in a 1-cylinder engine are measured.