Estimation of a Noise Level Using Coarse-Grained Entropy of Experimental   Time Series of Internal Pressure in a Combustion Engine
  We report our results on non-periodic experimental time series of pressure in a single cylinder spark ignition engine. The experiments were performed for different levels of loading. We estimate the noise level in internal pressure calculating the coarse-grained entropy from variations of maximal pressures in successive cycles. The results show that the dynamics of the combustion is a nonlinear multidimensional process mediated by noise. Our results show that so defined level of noise in internal pressure is not monotonous function of loading. 
Grzegorz Litak, Rodolfo Taccani, Krzysztof Urbanowicz, Janusz A.   Holyst, Miroslaw Wendeker, Alessandro Giadrossi