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The heat transfer phenomena in a turbo-charged diesel engine is simulated by integration of several CAE-tools including CFD, FEA and 1D codes for cooling system and gas exchange simulation. By using in-house methodologies 3D data is exchanged between CFD and FEA. The modelling time and the required computing power are thereby minimized. Two loops of thermal simulations are performed. The predicted temperatures are in good agreement with the measured data. The precision cooling strategy used here is efficient and it results in equally cooled cylinders. The engine temperatures in the sensitive regions are kept below the critical limits.

It is demonstrated that the cycle averaged heat flux on the hot gas side of the cylinders can be obtained using in-cylinder CFD-analysis. Together with the heat transfer coefficients obtained using a multi zone model in the coolant jacket CFD-analysis a complete set of thermal boundary conditions were made available exclusively based on simulations. The engine metal temperatures could then be predicted using FEA and compared with the measured data. Good agreement was obtained with the experimental data. The methodology has potential for refinement and application of a higher resolution in future. Also 1-D codes are used to provide cooling circuit boundary conditions and gas exchange boundary condition to the CFD-models.

It is demonstrated that the cycle averaged heat flux on the hot gas side of the cylinders can be obtained using in-cylinder CFD-analysis. Together with the heat transfer coefficient obtained from the coolant jacket CFD-analysis, a complete set of boundary conditions are made available exclusively based on simulations. The engine metal temperatures could then be predicted using FEA and the results are compared to an extensive set of measured data. Also 1-D codes are used to provide cooling circuit boundary conditions and gas exchange boundary condition for the CFD-models. The predicted temperature distribution in the engine is desirable for accurate and reliable prediction of knock, durability problems, bore distortion and valve seat distortion.

This paper reports test results of a compact, high pollutant conversion efficiency, catalytic muffler developed for utility engines (<19kW/25hp). Tests were conducted in-house, and at an independent laboratory under EPA supervision and funding, using a four-stroke engine generator set. The specific HC, CO and NOx emissions were reduced by 98%, 97%, and 19%, respectively. This level of reduction is thought to be sufficient for reducing such emissions from utility engines to the level of future standards such as 1999 CARB. A total of 200 hours of performance and limited durability testing were accumulated on the catalytic muffler. The prototype demonstrated successful operation by entraining fresh air and mixing with exhaust gas, converting pollutants, maintaining acceptable skin and exhaust gas temperatures, and muffling noise.

A primary surface counterflow, annular heat exchanger has been developed to minimize fuel consumption in vehicular gas turbines. Hot exhaust gas from the engine flows radially outwards and cooler air flows radially inwards, resulting in a maximum of 665 kW of energy transfer. The recuperator has been the major contributor to the high reputation earned by the Textron Lycoming AGT1500 automotive gas turbine engine with 10,000 engines shipped and over 6 million hours of total operation. The following paper describes the principles of aerothermal and structural design, the technological developments and the processes involved in the manufacture of the heat exchanger.