Calculation Model For The Optimization Of A Variable Distribution (Reduction Of The Pump-Losses)

It exists the possibility of adopting variable valve timings to reduce pump-losses in spark-ignition engines. With this method, engine load regulation can be achieved mainly by acting over the total time that the inlet valve remains open, and eliminating the throttle valve in an ideal case. The timing diagram (total opening valve and angular phase) should depend on the engine speed and load desired in each moment.

The mechanical system for the proposed regulation system is a four-bar mechanism which is now in a stage of final adjustment for a monocylinder engine.

In order to get the valve timing, a calculation model for the inlet and exhaust processes has been developed and is presented in this article, as well as the results obtained.