Reducing Cylinder-to-Cylinder Variation in a V-8 Natural Gas Engine With Cycle Simulation Techniques

During a recent project at Southwest Research Institute^® (SwRI^®), a medium-duty turbo-charged V-8 diesel engine was converted to natural gas operation for low-emission power generation applications. Initial cycle simulation studies indicated significant levels of cylinder-to-cylinder variation with the stock induction and exhaust system, which can limit the potential performance gains of a lean-burn spark-ignited engine due to spark knock and lean misfire. Cycle simulation techniques were used to investigate the sources of the cylinder-to-cylinder variation and determine potential solutions. The results indicated that significant improvements could be made with new intake and exhaust manifolds and a different turbocharger configuration.