Abstract
KEYWORDS
modeling, simulation, engine cycle, gas exchange, variable valve timing and lift, throttle-less
ABSTRACT
The purpose of this paper is the dynamic modeling and simulation of the engine cycle. For this stage, the engine is assumed to be a single cylinder unit. In order to “catch” the basic gas exchange phenomena, the model has been thought, as much as possible, as a collection of interconnected objects (blocks) that have a well determined physical meaning. Using this approach has to be done with care, and there is a special way to connect the individual blocks in order to achieve a good working simulation model. The gas exchange relies on the well-known filling-and-emptying model. For the in-cylinder processes, a simple Wiebe heat-release model was used. Some simplification hypotheses were taken into account, such as single phase gas mixture and completely homogeneous cylinder charge at any time. For this first model, the results look encouraging, especially because the model does not rely on empirical data – i.e. the results may be applied to any kind of engine. The final goal of the authors is to upgrade the model in order to simulate the throttle-less load engine control, when engine charge is regulated by using a variable valve timing device [Clenci et al 2005, Hara et al 2005]