System and method for predicting peak pressure values using knock sensor

A method for training a controller to estimate a peak firing pressure of a cylinder in a reciprocating engine, comprising:

• receiving a raw signal from at least one exterior sensor, wherein the raw signal comprises data corresponding to a peak firing pressure event;
• receiving a true pressure signal from a pressure sensor corresponding to the true peak firing pressure;
• deriving a filtered signal by applying a low pass or a band pass filter to the raw signal;
• deriving an absolute filtered signal from the filtered signal;
• identifying a maximum of the absolute filtered signal for each engine cycle;
• identifying the true peak pressure value for each engine cycle from the true pressure signal;
• mapping the maximums of the absolute filtered signal to the true peak pressure values;
• deriving predictive frequency bands for the peak firing pressure;
• and
• executing an algorithm to generate a predictive model using the maximums of the absolute filtered signal and the true pressure signal, wherein the predictive model is configured to estimate the peak firing pressure of the cylinder in the reciprocating engine during ordinary engine operation.

A system, comprising:

• a reciprocating engine controller configured to:
• receive a raw signal from at least one sensor coupled to a reciprocating engine;
• derive a filtered signal using predictive frequency bands by applying a low pass or band pass filter;
• derive an absolute filtered signal from the filtered signal;
• identify a maximum of the absolute filtered signal (MAFS) of each engine cycle;
• predict a peak firing pressure of each engine cycle using the identified MAFS and a predictive model;
• and
• output a control action for at least the reciprocating engine based on the predicted peak firing pressure, wherein the at least one sensor is disposed outside a cylinder.