Ion current sensing for estimation of combustion phasing in an internal combustion engine
AssigneeFca US LLC
InventorShuonan Xu
Life of this patent
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Abstract
A combustion control system for an engine of a vehicle includes an ion sensing system configured to generate an ion current signal indicative of a measured current across electrodes of a spark plug associated with a cylinder of the engine and a controller configured to monitor for peaks in the ion current signal and, upon detecting at least a first peak and a second peak in the ion current signal, estimate a location of peak pressure (LPP) based on the detected second peak in the ion current signal, estimate an angle (CA50) of a crankshaft of the engine at which approximately 50% of the heat generated during combustion in the cylinder of the engine is released, and control combustion phasing of the engine based on the estimated CA50 angle.
Claims14
A combustion control system for an engine of a vehicle, the system comprising:
- an ion sensing system configured to generate an ion current signal indicative of a measured current across electrodes of a spark plug associated with a cylinder of the engine;
- and
- a controller configured to monitor for peaks in the ion current signal and, upon identifying at least a first peak and a second peak in the ion current signal:
- estimate a location of peak pressure (LPP) based on the detected second peak in the ion current signal;
- estimate an angle (CA50) of a crankshaft of the engine at which approximately 50% of the heat generated during combustion in the cylinder of the engine is released;
- control combustion phasing of the engine based on the estimated CA50 angle;
- cycle average the ion current signal to reduce noise and obtain an averaged ion current signal;
- detect the second peak in the averaged ion current signal;
- and
- not estimate the LPP or estimate the CA50 crankshaft angle when the detected second peak is greater than a threshold distance from a first peak indicative of ringing after ignition of an air/fuel charge within the cylinder.
A combustion control method for an engine of a vehicle, the method comprising:
- obtaining, by a controller of the engine and from an ion sensing system of the engine, an ion current signal indicative of a measured current across electrodes of a spark plug associated with a cylinder of the engine;
- and
- monitoring, by the controller, for peaks in the ion current signal and, upon identifying, by the controller, at least a first peak and a second peak in the ion current signal:
- estimating, by the controller, a location of peak pressure (LPP) based on the detected second peak in the ion current signal;
- estimating, by the controller, an angle (CA50) of a crankshaft of the engine at which approximately 50% of the heat generated during combustion in the cylinder of the engine is released;
- controlling, by the controller, combustion phasing of the engine based on the estimated CA50 angle;
- cycle averaging, by the controller, the ion current signal to reduce noise and obtain an averaged ion current signal;
- and
- detecting, by the controller, the second peak in the averaged ion current signal;
- and
- not estimating, by the controller, the LPP or the CA50 crankshaft angle when the detected second peak is greater than a threshold distance from a first peak indicative of ringing after ignition of an air/fuel charge within the cylinder.
Dependencies are inferred from the claim text.