Patent ID: 8566062

Claim:
A method for processing a pressure signal originating from a pressure sensor mounted in a combustion chamber, for detecting combustion in an internal combustion engine, the processing of the pressure signal comprising: filtering the pressure signal by a filter having a variable gain; using the filter to establish an output signal representative of the filtered pressure signal; using a first comparison means to establish a first signal by comparing a value of the pressure signal and a first threshold; using a second comparison means to establish a second signal by comparing the value of the pressure signal and a second threshold; using a means to establish a signal representative of an error that can exist between the pressure signal and the output signal; using a third comparison means to establish a third signal by comparing a value of the error signal and a third threshold; using an RS flip-flop to establish, as an output of the RS flip-flop, a signal representative of a beginning of an expansion phase in the thermodynamic cycle, the RS flip-flop including a first input connected to an output of a first logic AND port the inputs of which are connected to the first and second signals, and a second input of the RS flip-flop is connected to an inverted representation of the second signal; and using a second logic AND port to establish, as an output of the second logic AND port, an intermediate signal that indicates that combustion has occurred in the combustion chamber in the expansion phase when the inputs of the second logic AND port include the signal output by the RS flip-flop indicating the beginning of the expansion phase in the thermodynamic cycle, an inverted representation of the first signal indicating that the value of the pressure signal is greater than the first threshold, and the third signal indicating that the value of the error signal is greater than or equal to the third threshold.