ESTIMATION OF CYLINDER CONDITIONS USING A KNOCK SENSOR

A reciprocating engine system includes a cylinder, a piston disposed within the cylinder, a knock sensor disposed proximate to the cylinder and configured to detect vibrations of the cylinder, piston, or both, a crankshaft sensor configured to sense a crank angle of a crankshaft, and a controller communicatively coupled to the knock sensor and the crankshaft sensor. The controller is configured to receive a raw knock signal from the knock sensor and a crank angle signal from the crankshaft sensor corresponding to vibrations of the cylinder, piston, or both relative to the crank angle of the crankshaft, convert the raw knock signal into a digital value signal, and at least one of a crank angle for a start of combustion, a peak firing pressure, a percentage of fuel mass fraction burn, or a combination thereof, based on the digital value signal and the crank angle.