Detecting engine misfire events for vehicles using filtering

A vehicle comprising:

• an internal combustion engine;
• a crank sensor associated with the internal combustion engine;
• and
• a processing system comprising:
• a memory comprising computer readable instructions;
• and
• a processing device for executing the computer readable instructions, the computer readable instructions controlling the processing system to perform operations for detecting engine misfire events for the internal combustion engine, the operations comprising:
• calculating an engine speed of the internal combustion engine based at least in part on a crank sensor signal received from the crank sensor at periodic intervals defined by a crank rotation;
• calculating an engine acceleration of the internal combustion engine based at least in part on the engine speed;
• generating, using a filter, a filtered engine acceleration of the internal combustion engine for the periodic intervals based at least in part on the engine acceleration;
• calculating a root mean square (RMS) engine acceleration of the internal combustion engine based at least in part on the filtered engine acceleration for the periodic intervals, wherein the RMS engine acceleration is calculated using the following equation:
• mod
• ⁡
• (
• B
• 0
• ⁢
• a
• k
• +
• B
• 1
• ⁢
• a
• k
• +
• B
• 2
• ⁢
• a
• k
• -
• 2
• +
• B
• 3
• ⁢
• a
• k
• -
• 3
• +
• A
• 1
• ⁢
• a
• k
• -
• 1
• ′
• +
• A
• 2
• ⁢
• a
• k
• -
• 2
• ′
• +
• A
• 3
• ⁢
• a
• k
• -
• 3
• ′
• a
• 0
• ,
• crank
• ⁢
• rotation
• )
• where A0 . . . AM and B0 . . . BN are coefficients that are precalculated for the filter, M and N are integers, ak, ak-1, ak-2, ak-3 are unfiltered acceleration for a current sample and three prior samples, a′k, a′k-1, a′k-2, a′k-3 are filtered acceleration for the current sample and the three prior samples, and k represents an amount of the crank rotation in degrees;
• detecting an engine misfire event of the internal combustion engine based at least in part on the RMS engine acceleration;
• and
• implementing a corrective action for the vehicle in response to detecting the engine misfire event.

A computer program product comprising a computer readable storage medium having program instructions embodied therewith, the program instructions executable by at least one processor to cause the at least one processor to perform operations for detecting engine misfire events for an engine of a vehicle, the operations comprising:

• calculating an engine speed based at least in part on a crank sensor signal received from a crank sensor of the engine at periodic intervals defined by a crank rotation;
• calculating an engine acceleration based at least in part on the engine speed;
• generating, using a filter, a filtered engine acceleration for the periodic intervals based at least in part on the engine acceleration;
• calculating a root mean square (RMS) engine acceleration based at least in part on the filtered engine acceleration for the periodic intervals, wherein the RMS engine acceleration is calculated using the following equation:
• mod
• ⁡
• (
• B
• 0
• ⁢
• a
• k
• +
• B
• 1
• ⁢
• a
• k
• +
• B
• 2
• ⁢
• a
• k
• -
• 2
• +
• B
• 3
• ⁢
• a
• k
• -
• 3
• +
• A
• 1
• ⁢
• a
• k
• -
• 1
• ′
• +
• A
• 2
• ⁢
• a
• k
• -
• 2
• ′
• +
• A
• 3
• ⁢
• a
• k
• -
• 3
• ′
• a
• 0
• ,
• crank
• ⁢
• rotation
• )
• where A0 . . . AM and B0 . . . BN are coefficients that are precalculated for the filter, M and N are integers, ak, ak-1, ak-2, ak-3 are unfiltered acceleration for a current sample and three prior samples, a′k, a′k-1, a′k-2, a′k-3 are filtered acceleration for the current sample and the three prior samples, and k represents an amount of the crank rotation in degrees;
• detecting an engine misfire event based at least in part on the RMS engine acceleration;
• and
• implementing a corrective action for the vehicle in response to detecting the engine misfire event.