Fuel reid vapor pressure estimation
First Claim
1. A method for estimating automotive internal combustion engine fuel volatility in an internal combustion engine selectively receiving fuel vapors trapped in a fuel vapor recovery system, comprising the steps of:
- admitting fuel vapors from the fuel vapor recovery system to the engine for combustion therein;
determining a change in engine fueling resulting from the admission of fuel vapors from the fuel vapor control system to the engine; and
estimating fuel volatility as a function of the determined change.
1 Assignment
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Accused Products
Abstract
Automotive internal combustion engine control and diagnostics responsive to an up-to-date on-board estimate of fuel reid vapor pressure (RVP). An on-board fuel vapor recovery system traps fuel vapors released from a fueling system and is controlled to release the vapors to the engine for consumption therein, along with an injected fuel charge under closed-loop engine air/fuel ratio control. The change in the injected fuel charge required to maintain, under closed-loop control conditions, a target air/fuel ratio in the presence and in the absence of the released fuel vapors is applied along with fuel temperature information to estimate RVP, and the RVP estimate is applied under coldstart operating conditions to adjust engine fueling to account for corresponding changes in the vaporization characteristic of the fuel and is applied, when determined to be relatively high, to indicate potential false positives in fuel vapor recovery system diagnostics.
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Citations
12 Claims
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1. A method for estimating automotive internal combustion engine fuel volatility in an internal combustion engine selectively receiving fuel vapors trapped in a fuel vapor recovery system, comprising the steps of:
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admitting fuel vapors from the fuel vapor recovery system to the engine for combustion therein; determining a change in engine fueling resulting from the admission of fuel vapors from the fuel vapor control system to the engine; and estimating fuel volatility as a function of the determined change. - View Dependent Claims (2, 3, 4, 5, 6)
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7. A method for controlling internal combustion engine fueling in response to estimated fuel reid vapor pressure (RVP), comprising the steps of:
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trapping fuel vapors in an on-board re-fueling vapor recovery (ORVR) system; generating a closed-loop engine fueling command; releasing the trapped fuel vapors from the ORVR system for consumption in the engine; determining a change in the closed-loop engine fueling command resulting from the release of the trapped fuel vapors; estimating fuel RVP as a function of the determined change; and controlling fueling in response to the estimated fuel RVP. - View Dependent Claims (8, 9, 10, 11, 12)
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Specification