The present work aims to study the optimal parameter
configuration for different operating and design variables of a
spark ignition engine with the goal of minimizing the cyclic
variability (CV) of its efficiency time series. We make use of a
quasi-dimensional numerical simulation of a mono-cylindrical
spark ignition engine. The CV is modelled by incorporating a
stochastic component in the characteristic length and the
velocity of the turbulent combustion model.
The focus of this work is to reduce CV through the
reduction of the coefficient of variation, considering five
different parameters, related to the crankshaft angle, that have
incidence in CV: the spark advance, the intake valve opening
angle, the intake valve closing angle, the exhaust valve opening
angle, and the exhaust valve closing angle. A Random Search
method was used for sampling the search space of the different
parameters, considering a discretization angle of one degree.
The results show that a significant reduction in the coefficient
of variation can be obtained by appropriately choosing the
parameter values for the different operating scenarios of the
spark ignition engine. The experimental evaluation also shows
that the two most relevant parameters with a greater incidence
in reducing the coefficient of variation are the spark advance
and the intake opening valve angle.
Papers presented to the 12th International Conference on Heat Transfer, Fluid Mechanics and Thermodynamics, Costa de Sol, Spain on 11-13 July 2016.