The effects of heat transfer on performance and exergy destruction for a turbocharged, spark-ignition engine

The use of the second law of thermodynamics is a powerful means for assessing the performance of engines, and is the only way to determine the destruction of exergy. This work has examined a turbocharged, spark-ignition engine in some detail, and in particular, has quantified the effects of varying the engine cylinder heat transfer. A thermodynamic simulation was developed to investigate these effects from both the first law and second law perspectives. The engine used for this study was a 3.8 l, V-6, turbocharged engine with an intercooler. The engine was examined for various levels of heat transfer. The exergy values associated with the components of the turbocharger along with the engine components were quantified as a percentage of fuel exergy. For the base case operating conditions (full load, 2000 r/min) about 20.5 per cent of the exergy was destroyed during the combustion process, and the turbocharger components were responsible for less than 1 per cent of the exergy destruction. As the heat transfer level decreased, work increased only slightly while the exhaust energy and exergy increased much more significantly. Although engine performance was altered as the heat transfer level was changed, the destruction of exergy remained nearly constant.