OPTIMIZATION OF SPARK TIMING AND AIR-FUEL RATIO OF AN SI ENGINE WITH VARIABLE VALVE TIMING USING GENETIC ALGORITHM AND STEEPEST DESCEND METHOD

In this study, optimization of inlet and exhaust valve timing as well as spark timing and air-fuel ratio in XU7/L3 engine has been conducted in order to reduce fuel consumption and increase engine torque. At first, engine model in GT-POWER software is produced, and then it is optimized using sensitivity analysis. Unknown input data are arranged based on their sensitivity and the most effective of them is selected and optimized. Heat transfer coefficient of the cylinder, temperature and friction coefficient of the inlet port are the most important unknown parameters which affect the model, and optimization of them reduce errors of the model with the experimental results. Since determining the optimal operation points of the engine is not possible just with GT-Power software, it is coupled with MATLAB. The results are in full load case and shows 5% and 5.1% reduction in the fuel consumption as well as enhancement of 5.65% and 6% in torque by using genetic algorithm and steepest descend, respectively.

[1]  J. Andrus,et al.  A steepest descents method for reentry optimization , 1975 .

[2]  Ugur Kesgin,et al.  Genetic algorithm and artificial neural network for engine optimisation of efficiency and NOx emission , 2004 .

[3]  B. Svaiter,et al.  A steepest descent method for vector optimization , 2005 .

[4]  Yakup Sekmen,et al.  Artificial neural-network based modeling of variable valve-timing in a spark-ignition engine , 2005 .

[5]  Fernando Cruz-Peragón,et al.  A genetic algorithm for determining cylinder pressure in internal combustion engines , 2007 .

[6]  Vicente Hernández,et al.  Combining Neural Networks and Genetic Algorithms to Predict and Reduce Diesel Engine Emissions , 2007, IEEE Transactions on Evolutionary Computation.

[7]  M. SaniM.S.,et al.  Study of Air Fuel Ratio on Engine Performance of Direct Injection Hydrogen Fueled Engine , 2008 .

[8]  Nicolas Petit,et al.  Motion planning for experimental air path control of a variable-valve-timing spark ignition engine , 2009 .

[9]  F. Salimi,et al.  Role of mixture richness, spark and valve timing in hydrogen-fuelled engine performance and emission , 2009 .

[10]  Bo Zhang,et al.  Effect of spark timing on the performance of a hybrid hydrogen-gasoline engine at lean conditions , 2010 .

[11]  Jun Li,et al.  Effect of injection and ignition timings on performance and emissions from a spark-ignition engine fueled with methanol , 2010 .

[12]  Sedat Bayseç,et al.  Genetic programming approach to predict torque and brake specific fuel consumption of a gasoline engine , 2010 .

[13]  M. Pishgooie,et al.  Determination of optimal valve timing forinternal combustion engines using parameterestimation method , 2011 .