Variable valve timing represents one of the key technologies in further development of automotive engines.Different valve lift profiles and variable valve timing in the engine operation map offer the flexibility to better meet the load specific engine requirements regarding the intake flow conditions, the exhaust gas control and the efficiency of load exchange, mixture preparation and combustion.Mechanical solutions for continuously variable valve lift and timing are based on different principles such as: This paper describes the specific kinematics of different mechanical principles and illustrates the resulting properties and restrictions considering lift/event-ratio, phasing of the opening event, minimum and maximum valve lift, valve acceleration, as well as precision requirements.The thermodynamic characteristics like benefits in full-load performance, reductions in pumping losses, support of mixture preparation and idle quality will be discussed on the base of load exchange calculations as well as test bench results.
Comparison of Different Kinematic Solutions for Mechanical Continuously Variable Valve Lift Systems
Sae Technical Papers
SAE 2004 World Congress & Exhibition ; 2004
2004-03-08
Aufsatz (Konferenz)
Englisch
Comparison of Different Kinematic Solutions for Mechanical Continuously Variable Valve Lift Systems
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