Fast on-line identification of instantaneous mechanical losses in internal combustion engines

A fast and easy procedure to evaluate instantaneous mechanical losses in internal combustion engines (appropriate to any multi-cylinder engine) has been developed. First, a performance measurement procedure to obtain losses in one cycle is conducted. Subsequently, they must be proportionally divided into all cylinders, even considering those with no combustion. Finally, a non-linear identification procedure is applied to determine the coefficients of the P–ω method for each cylinder. The methodology has been applied to a single-cylinder compression ignition engine, and to a three-cylinder spark ignition engine. The first engine allows the procedure to be validated by comparing results with those obtained using other established methodology. The second engine makes it possible to analyze the robustness of the method when it is applied to a multi-cylinder engine.