Search Results

A 2.0 l turbo charged gasoline engine with the mechanically fully variable mechanical valve train UniValve has been investigated on a test bed at the University of Kaiserslautern. First results of the mechanical behaviour, full load behaviour and fuel consumption at part load have been measured. These results are compared to the uncharged gasoline engine. In both cases the engines have been driven throttled and throttled free through the variable valve train. The dynamic behaviour of the turbocharger version has been investigated too. The only modification of the engine is the turbo charger, the valve train and the intake manifold hasn't been changed. The results have been compared with GT-Power simulations. The fuel consumption in the turbo charged mode at the map point 2,000 rpm/2bar could be improved up to 14 % through the throttle free load control vs. the throttled mode. The low end torque has been increased by 10 %.

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 mechanical fully variable valve lift system UniValve represents one of the new technical solutions for a throttle free load control for combustion engines. The load control is achieved by the variation of the valve lift and the simultaneous variation of the opening and closing time. The design of the system has as result a simple layout with a valve train component assembly that leads to a compact integration into conventional cylinder heads. In addition to the first results presented at the SAE Congress 2004 this paper provides the results of the fired engine and the valve train operation on the component test bench. Furthermore the potentials of the throttle free load control with the UniValve system in comparison to a conventional throttle engine operation with the same engine type are pointed out. Perspectives for the application in an four cylinder engine are given.