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An experimental procedure to determine the two components of the crankshaft force on the bearing cap is presented in this work. The method is based on the use of two load cells, one in each bearing cap bolt. A system to calibrate the force transference from the bearing cap to the load cells has been used. This system allows the calculation of the two components of the crankshaft forces as a function of the load cells signals. Some experiments have been done with this system, and the results of a firing and motored engine have been compared in order to know the influence of combustion and inertia forces on the crankshaft load in the bearing cap. The results are compared with a model for the dynamics of the piston-connecting rod-crankshaft system.

Electrical power and efficiency are decisive factors to minimise payoff time of cogeneration units and thus increase their profitability. In the case of (small-scale) cogeneration engines, low-NOx operation and high engine efficiency are frequently achieved through lean burn operation. Whereas higher diluted mixture enables future emission standards to be met, it reduces engine power. It further leads to poor combustion phasing, reducing engine efficiency. In this work, an engine concept that improves the trade-off between engine efficiency, NOx emissions and engine power, was investigated numerically. It combines individual measures such as lean burn operation, overexpanded cycle as well as a power- and efficiency-optimised intake system. Miller and Atkinson valve timings were examined using a detailed 1D model (AVL BOOST). Indicated specific fuel consumption (ISFC) was improved while maintaining effective compression ratio constant.