Patent ID: 8606484

Claim:
An in-cylinder pressure measurement apparatus that measures an in-cylinder pressure of an internal combustion engine, comprising: crank angle detection means that detects a crank angle of the internal combustion engine; crank angle recording means that records time history of the detected crank angle; in-cylinder pressure detection means that detects an in-cylinder pressure; in-cylinder pressure recording means that records time history of the detected in-cylinder pressure; peak in-cylinder pressure 1 detection means that detects a peak value of the in-cylinder pressure for each combustion cycle on a basis of the recorded time history of the in-cylinder pressure; time 1 detection means that detects a time when the in-cylinder pressure for each combustion cycle reaches a peak on a basis of the recorded time history of the in-cylinder pressure; crank angle 1 detection means that detects a crank angle 1 where the in-cylinder pressure for each combustion cycle reaches a peak on a basis of the recorded time history of the crank angle; exhaust pressure detection means disposed in an exhaust port of the internal combustion engine to detect an exhaust pressure in the exhaust port; exhaust pressure recording means that records time history of the detected exhaust pressure; peak exhaust pressure detection means that detects a peak value of the exhaust pressure for each pulsation cycle on a basis of the recorded time history of the exhaust pressure; peak in-cylinder pressure 2 operation means that calculates a peak value of the in-cylinder pressure for each combustion cycle using the detected peak value of the exhaust pressure; time 2 detection means that detects a time when the exhaust pressure for each pulsation cycle reaches a peak on a basis of the recorded time history of the exhaust pressure; crank angle 2 detection means that detects a crank angle 2 where the exhaust pressure for each pulsation cycle reaches a peak on a basis of the recorded time history of the crank angle; reference crank angle setting means that sets a reference crank angle so that a deviation between a crank angle 1 and a crank angle 2 where the exhaust pressure generated by the in-cylinder pressure reaching a peak at the time of the cylinder angle 1 becomes substantially constant in a plurality of combustion cycles; crank angle combination detection means that compares a sum of the reference crank angle and a crank angle 1 with a crank angle 2 in a plurality of combustion cycles to detect a combination of a crank angle 1 and a crank angle 2 having a minimum difference therebetween; operation means that calculates, in the detected combination of crank angles, a pressure deviation between a peak in-cylinder pressure 2 calculated from the exhaust pressure at the crank angle 2 using the peak in-cylinder pressure 2 operation means and a peak in-cylinder pressure 1 at the crank angle 1 ; and correction means that corrects an output characteristic of the in-cylinder pressure detection means using the calculated pressure deviation.