RT info:eu-repo/semantics/article T1 Adaptive polynomial filter applied to in-cylinder pressure signal in internal combustion engines A1 Gabana Molina, Pedro A1 Giménez Olavarría, Blanca A1 Melgar Bachiller, Andrés A1 Horrillo Güemes, Alfonso Jesús K1 Adaptative filter K1 Polynomial filter K1 Savitzky-Golay filter K1 ICE pressure diagnostic K1 Cycle averaging K1 33 Ciencias Tecnológicas AB Pressure record processing is a powerful tool for research and diagnosis of internal combustion engines. From the pressure record, using the energy conservation equation, it is possible to calculate the rate of heat release () and thus quantify the evolution of the combustion process. In order to obtain accurate results, it is necessary to remove as much noise as possible from the pressure signal, without removing relevant information from the studied phenomenon. In reciprocating internal combustion engines, pressure data are recorded discretely and synchronized with the crankshaft angle. Both pressure signal and its derivative are used incalculation. For the integration of differential equations using data as a boundary condition, it is necessary to have no discontinuities in the function and its derivative.This work presents a novel methodology for filtering discrete data adaptively and converting it into a continuous and derivable function. For this, polynomial fits are used in each interval between two experimental data. The polynomial order and the number of points used to make the fit are chosen depending on the value taken by a convolution of the signal. With the adaptive filter it is possible to reduce noise significantly in parts of the cycle where signal-to-noise ratio is low without affecting the parts where signal-to-noise ratio is high. The novelty and main advantage of this filtering methodology is that it is configured with only one parameter independent of the operating conditions of the engine while preserving the information of cycle-to-cycle variations. PB Elsevier SN 0888-3270 YR 2025 FD 2025 LK https://uvadoc.uva.es/handle/10324/76747 UL https://uvadoc.uva.es/handle/10324/76747 LA eng NO Mechanical Systems and Signal Processing, 2025, vol. 235, p. 112871 NO Producción Científica DS UVaDOC RD 26-jul-2025