Improvements to a Four Cylinder Gasoline Engine Through the Fully Variable Valve Lift and Timing System UniValve®

In addition to first test results from a one single-cylinder engine with the UniValve fully variable valve lift and timing system - presented at the 2005 SAE Congress - this paper contains the results of a fired 2.0 I four cylinder gasoline engine [1], [2]. The cylinder head has been replaced with a new cylinder head concept that includes the fully variable valve lift and timing system (VVTL system) UniValve. The other engines parameters and components have not been changed. The intention was to investigate the engine behavior only by exchanging the standard inlet valve train with for the UniValve fully variable valve train. The VVT engine load can be controlled either with a standard throttle or unthrottled, only through the fully variable variation of the valve lift and the valve opening period. The engine has been installed on a dynamic test bench. The torque behavior, the power output, the raw emissions and the fuel consumption have been measured for the standard series production engine directly in comparison with the VVT engine. The VVT engine was driven with both load control options. With different valve lift heights of two adjacent inlet valves the flow turbulence can be increased. This influence of this inlet valve phasing on the fuel consumption and on the emissions at part load will be measured on the UniValve engine too in 2006 too. With a special design of the turnable eccentric control shaft the engine can be driven with different loads for defined cylinder groups, so that for example for a specific engine load point a cylinder group runs with low load while the other cylinder group works with higher load. This load control strategy is called “Cylinder Up Loading”. The target therefore is to get still a higher efficiency and a better fuel consumption at higher part loads.