Method of monitoring the operation of an internal combustion engine

Claim 1

A method of monitoring, in a motor vehicle, an internal combustion engine thereof comprising a plurality of cylinders having a predetermine power stroke sequence, means for detecting faltering transmission of torque from said engine, means for monitoring combustion by torque falters, means for electrical monitoring of ignition failure and failure rate and identification of cylinder affected by ignition failure and means for determining conditions for plausible detection of isolated ignition failures, said method including the steps of: (1) determining whether circumstances of engine operation are such that faltering torque information is useful for detecting combustion failure; (2) if circumstances of ignition operation are found useful for detecting combustion failures by torque falters, monitoring combustion failures thereby and determining whether torque falters are more frequent then a predetermined falter rate (α); (3) if torque falters are found more frequent then said predetermined falter rate (α), registering an combustion failure, identifying an affected cylinder and producing a cylinder-specific remedy and thereafter returning to step 1 of this method for another power stroke; (4) if circumstances of engine operation are found unfavorable for detecting combustion failures by torque falters, electrically monitoring ignition failure rate and thereby determining whether ignition failures are more frequent than a predetermined ignition failure rate (β); (5) if an ignition failure rate exceeding said predetermined ignition failure rate (β) is found, registering an ignition failure, identifying an affected cylinder, producing a cylinder-specific remedy and thereby after returning to step (1) of this method for another power stroke; (6) if an ignition failure rate is found which is not greater than said predetermined ignition rate (β) and if a torque falter rate is found which is not greater than said predetermined torque falter rate (α), determining whether engine operating conditions are such that electrical detection of an individual ignition failure would be plausible, and if so, determining electrically whether in the present power stroke an individual ignition failure takes place; (7) if an individual ignition failure is found to have taken place in step (6) of this method, registering an isolated ignition error and returning to step (1) of this method for another power stroke, and (8) if in step (6) ignition operating conditions are found to be such that the electrical detection of an individual ignition error would be implausible, or if in step (7) no individual ignition error is detected, returning to step (1) of this method for a succeeding power stroke.

Claim 2

A method of monitoring, in a motor vehicle, an internal combustion engine thereof comprising a plurality of cylinders having a predetermine power stroke sequence, means for detecting faltering transmission of torque from said engine, means for monitoring combustion by torque falters, means for electrical monitoring of ignition failure and failure rate and identification of cylinder affected by ignition failure and means for determining conditions for plausible detection of isolated ignition failures, said method including the steps of: (1) determining whether circumstances of engine operation are such that faltering torque information is useful for detecting combustion failure; (2) if circumstances of ignition operation are found useful for detecting combustion failures by torque falters, monitoring combustion failures thereby and determining whether torque falters are more frequent then a predetermined falter rate (α); (3) if torque falters are found more frequent then said predetermined falter rate (α), registering an combustion failure, identifying an affected cylinder and producing a cylinder-specific remedy and thereafter returning to step 1 of this method for another power stroke; (4) if circumstances of engine operation are found unfavorable for detecting combustion failures by torque falters, electrically monitoring ignition failure rate and thereby determining whether ignition failures are more frequent than a predetermined ignition failure rate (β); (5) if an ignition failure rate exceeding said predetermined ignition failure rate (β) is found, registering an ignition failure, identifying an affected cylinder, producing a cylinder-specific remedy and thereby after returning to step (1) of this method for another power stroke; (6) if an ignition failure rate is found which is not greater than said predetermined ignition rate (β) and if a torque falter rate is found which is not greater than said predetermined torque falter rate (α), determining whether engine operating conditions are such that electrical detection of an individual ignition failure would be plausible, and if so, determining electrically whether in the present power stroke an individual ignition failure takes place; (7) if an individual ignition failure is found to have taken place in step (6) of this method, registering an isolated ignition error and returning to step (1) of this method for another power stroke, and (8) if in step (6) ignition operating conditions are found to be such that the electrical detection of an individual ignition error would be implausible, or if in step (7) no individual ignition error is detected, returning to step (1) of this method for a succeeding power stroke.