Independent timing retard for engine speed limiting
AssigneeWalbro Engine Management, L.L.C.
InventorsMartin N. Andersson, George M. Pattullo
Life of this patent
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Abstract
A method and system for operating an engine wherein ignition of the engine is activated according to a predetermined timing schedule that references engine speed, and the ignition is suppressed above a predetermined engine speed threshold to allow engine speed to fall below the predetermined engine speed threshold. Thereafter, ignition is reactivated according to timing that is retarded relative to the predetermined timing schedule for a predetermined number of engine revolutions substantially when the engine speed has fallen below the predetermined engine speed threshold, thereby mitigating undesirable spikes in combustion chamber maximum pressure.
Claims22
A method of operating an engine, comprising the steps of:
- determining engine speed;
- activating ignition of said engine according to a predetermined timing schedule that references said determined engine speed;
- suppressing ignition of said engine above at least one predetermined engine speed threshold to allow said engine speed to fall below said at least one predetermined engine speed threshold;
- and
- reactivating ignition of said engine according to timing that is retarded relative to said predetermined timing schedule for at least a portion of at least one revolution of said engine substantially when said engine speed has fallen below said at least one predetermined engine speed threshold.
A method of controlling ignition of an engine, comprising the steps of:
- receiving a signal representative of engine revolutions;
- converting said signal into an engine speed value;
- comparing said engine speed value to at least one predetermined engine speed threshold;
- generating a timing advance signal in accordance with a predetermined timing schedule;
- generating an ignition suppression signal when said engine speed value exceeds said at least one predetermined engine speed threshold;
- and
- generating a timing retard signal for at least a portion of at least one revolution of said engine substantially when said engine speed value falls below said at least one predetermined engine speed threshold.
An ignition control system for use with a light duty combustion engine, said system comprising an engine speed sensing apparatus, and an electronic processing device coupled to said engine speed sensing apparatus so as to receive signals indicative of engine speed from said engine speed sensing apparatus, said electronic processing device using a predetermined timing schedule to generate a timing advance signal based thereon, said electronic processing device generating an ignition suppression signal when said engine speed exceeds at least one predetermined engine speed threshold, said electronic processing device generating a timing retard signal for at least a portion of at least one revolution substantially when said engine speed has fallen below said at least one predetermined engine speed threshold.
An ignition control system for an engine, comprising:
- means for determining engine speed;
- means for activating ignition of said engine according to a predetermined timing schedule that references said determined engine speed;
- means for suppressing ignition of said engine above at least one predetermined engine speed threshold to allow said engine speed to fall below said at least one predetermined engine speed threshold;
- and
- means for reactivating ignition of said engine according to timing that is retarded relative to said predetermined timing schedule for at least a portion of at least one revolution of said engine substantially when said engine speed has fallen below said at least one predetermined engine speed threshold.
An ignition control system for an engine, comprising:
- means for receiving a signal representative of engine revolutions;
- means for converting said signal into an engine speed value;
- means for comparing said engine speed value to at least one predetermined engine speed threshold;
- means for generating a timing advance signal in accordance with a predetermined timing schedule;
- means for generating an ignition suppression signal when said engine speed value exceeds said at least one predetermined engine speed threshold;
- and
- means for generating a timing retard signal for at least a portion of at least one revolution of said engine substantially when said engine speed value falls below said at least one predetermined engine speed threshold.
Dependencies are inferred from the claim text.