Abstract
It is very useful to combine 1-D pipe model with 0-D approach to the remaining engine parts. Based on previous research at authors department, such a combination should be capable to capture important features regarding tuned manifold systems. The main target of this work was to test the influence of variable valve timing (VVT) system, the different intake and exhaust manifold configurations and application of variable intake manifold length (VML) system on important engine output parameters (e.g. engine power, BSFC, etc.).
This is a theoretical study that is why presented results have only qualitative meaning. The presented data represent theoretical limits for real engine, the improvements would most likely be smaller when compared with reference model.
Therefore, a model of artificial engine (reference model) was created even though it is based on a real one. Another reason for creating simplified model was the need to shorten computation time as much as possible to enable multi-parametric optimizations within acceptable time limits.
The work was based on optimization of certain variables (e.g. when applying VVT system, timing for both intake and exhaust valve were optimized at each engine speed). The optimization criterion was engine power. In fact, some other parameters were optimized for maximum engine power as well this applied to all variables which were supposed to be kept constant for computation of full throttle speed characteristics (e.g. pipe lengths, valve cams, etc.).