METHODS AND SYSTEMS FOR ENGINE FUEL AND TORQUE CONTROL
First Claim
1. A method for an engine, comprising:
- sampling an intake oxygen sensor signal at even increments of time;
storing each sampled signal in a buffer;
processing the stored sampled signals in the buffer at even increments of engine crank angle; and
adjusting an engine operating parameter based on a selected two or more of the processed sampled signals.
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Accused Products
Abstract
Methods and systems are provided for accurately estimating intake aircharge based on the output of an intake oxygen sensor while flowing EGR, purge, or PCV hydrocarbons to the engine. The unadjusted aircharge estimate is used for engine fuel control while the hydrocarbon adjusted aircharge estimate is used for engine torque control. A controller is configured to sample the oxygen sensor at even increments in a time domain, stamp the sampled data in a crank angle domain, store the sampled data in a buffer, and then select one or more data samples corresponding to a last firing period from the buffer for estimating the intake aircharge.
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Citations
20 Claims
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1. A method for an engine, comprising:
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sampling an intake oxygen sensor signal at even increments of time; storing each sampled signal in a buffer; processing the stored sampled signals in the buffer at even increments of engine crank angle; and adjusting an engine operating parameter based on a selected two or more of the processed sampled signals. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10)
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11. A method for an engine, comprising:
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sampling an intake manifold oxygen sensor signal at predetermined time intervals to generate a data set including a plurality of samples; stamping each sample of the data set with an engine crank angle; and in response to a fuel injection request, adjusting fuel injection based on an intake aircharge amount estimated based on a selected two or more samples of the data set, the selected two or more samples having an engine crank angle stamp corresponding to one firing period immediately preceding the fuel injection request. - View Dependent Claims (12, 13, 14, 15)
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16. A system, comprising:
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an engine having a cylinder supplied with intake air from an intake passage; an oxygen sensor coupled to the intake passage; a fuel system including a fuel tank coupled to a canister for storing fuel vapors, a purge passage for purging canister fuel vapors to the intake passage, and a purge valve coupled to the purge passage; an exhaust gas sensor coupled to an exhaust passage; a direct fuel injector for injecting fuel into the cylinder; and a controller with computer readable instructions stored on non-transitory memory for; while purging fuel vapors from the canister to the intake passage, sampling a signal from the oxygen sensor at a predetermined sampling rate; for each sample, stamping the sample with a corresponding engine crank angle; storing each stamped sample in a buffer; and responsive to a request to inject fuel into the cylinder, retrieving at least two samples from the buffer having a crank angle stamp corresponding to a firing period immediately preceding the request; calculating an aircharge estimate for the cylinder based on an average of the retrieved at least two samples; determining a fuel injection amount based on the calculated aircharge estimate; correcting the fuel injection amount based on a learned fuel injector error; and commanding a pulse width to the fuel injector based on the corrected fuel injection amount. - View Dependent Claims (17, 18, 19, 20)
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Specification