Method of detecting misfire in an internal combustion engine

A method of detecting misfire in an internal combustion engine, the engine having a plurality of cylinders, a corresponding plurality of pistons, and a shaft operatively connected to the plurality of pistons, the shaft having a longitudinal axis about which the shaft rotates, the method comprising:

• sensing a temporal signature of a lateral displacement of the engine via an acceleration sensor, the acceleration sensor sensing the lateral displacement in at least one direction, the at least one direction being non-parallel relative to the longitudinal axis of the shaft, the acceleration sensor being connected to a control unit, the temporal signature being decomposable into a plurality of frequencies, associated magnitudes, and associated phase angles, each of the plurality of frequencies being associated with a corresponding one of a plurality of orders of the engine;
• sending a signal corresponding to the temporal signature of the lateral displacement from the acceleration sensor to the control unit;
• processing the signal with the control unit, the processing comprising:
• performing a spectral analysis of the temporal signature of the lateral displacement to extract magnitudes of at least some of the plurality of frequencies;
• adding the magnitudes of the at least some of the plurality of frequencies to obtain an added magnitude;
• and
• determining that misfiring in at least one of the plurality of cylinders has occurred based on the added magnitude.

A method of detecting misfire in an internal combustion engine, the engine having a plurality of cylinders, a corresponding plurality of pistons, and a shaft operatively connected to the plurality of pistons, the shaft having a longitudinal axis about which the shaft rotates, the method comprising:

• sensing a temporal signature of a lateral displacement of the engine via an acceleration sensor, the acceleration sensor sensing the lateral displacement in at least one direction, the at least one direction being non-parallel relative to the longitudinal axis of the shaft, the acceleration sensor being connected to a control unit;
• sending a signal corresponding to the temporal signature of the lateral displacement from the acceleration sensor to the control unit;
• filtering the signal with the control unit to obtain an engine displacement component associated with frequencies below a predetermined frequency and an engine displacement component associated with frequencies above the predetermined frequency;
• and
• determining that misfiring in at least one of the plurality of cylinders has occurred based on a comparison between the engine displacement component associated with frequencies below the predetermined frequency and the engine displacement component associated with frequencies above the predetermined frequency.

A vehicle comprising:

• a frame;
• an internal combustion engine mounted to the frame, the internal combustion engine including:
• a plurality of cylinders;
• a plurality of pistons, each of the plurality of piston being movably connected to a corresponding one of the plurality of cylinders;
• and
• a shaft operatively connected to the plurality of pistons, the shaft having a longitudinal axis about which the shaft rotates;
• a plurality of engine mounts for mounting the engine to the frame;
• an acceleration sensor mounted on the engine, the acceleration sensor sensing a temporal signature of a lateral displacement of the engine in at least one direction, the at least one direction being non-parallel relative to the longitudinal axis of the shaft, the temporal signature being decomposable into a plurality of frequencies, associated magnitudes, and associated phase angles, each of the plurality of frequencies being associated with a corresponding one of a plurality of orders of the engine;
• a control unit connected to the acceleration sensor, the acceleration sensor sending a signal corresponding to the temporal signature of the lateral displacement to the control unit, the control unit processing the signal,
• the processing consisting in:
• performing a spectral analysis of the temporal signature of the lateral displacement to extract a magnitude of a predetermined frequency, the predetermined frequency being associated with one of the plurality of orders of the engine, the one of the plurality of orders being representative of engine lateral displacement due to in-cylinder pressures;
• and
• determining that misfiring in at least one of the plurality of cylinders has occurred based on the magnitude of the predetermined frequency.