Internal-combustion engines – Charge forming device – Having fuel vapor recovery and storage system
Reexamination Certificate
2003-02-28
2004-08-03
Dolinar, Andrew M. (Department: 3747)
Internal-combustion engines
Charge forming device
Having fuel vapor recovery and storage system
C123S179140
Reexamination Certificate
active
06769418
ABSTRACT:
TECHNICAL FIELD
This invention relates to engine fuel systems and, more particularly, to systems with fuel vapor generation for engine cold starting.
BACKGROUND OF THE INVENTION
Under current regulations, all automobile companies will be required to produce some super ultra-low emission vehicles (SULEVs) to meet California regulations. Currently, cold start hydrocarbon (HC) emissions during the first 20 to 30 seconds of cold engine operation account for 70-80% of the total HC emissions in the federal test procedure (FTP) at 75° Fahrenheit. The cold start emissions occur because only about 50% of injected gasoline fuel vaporizes for combustion and the rest escapes as cold start emissions. The problem can get worse for emission certification at 50° F. ambient temperature. Most of the solutions considered for the cold start emission problem are complicated and/or costly involving one or more expensive devices for assisting cold start emission control. A practical approach involving a relatively simple system with supplemental devices having reasonable manufacturing costs was desired.
SUMMARY OF THE INVENTION
The present invention provides an engine fuel system including liquid fuel delivery and fuel vapor generation for use in cold starting on fuel vapor alone. A fuel vapor generator is preferably contained in the vehicle fuel tank. The vapor generator includes a vapor collector connected in a return line between a pressure regulator and an in-tank fuel pump to which returning liquid fuel is passed from the pressure regulator through the vapor collector.
The system may further include a charging portion including a vapor storage cold start canister and a vapor pump arranged to pump or draw fuel vapor from the vapor collector to the cold start canister for storage until needed for cold starting. A return line is connected between the canister and a liquid containing portion of the vapor collector to provide for circulation of the vapor into the canister.
A vapor delivery portion may also be included having a vapor delivery line connected between an outlet portion of the cold start canister and an air inlet of an associated engine. The vapor pump may include an air inlet line for delivering air to the canister during cold starting.
The system may also include a relatively conventional liquid fuel delivery portion including connections from the in-tank fuel pump through the pressure regulator and a fuel control to a liquid fuel injector for injecting fuel into an associated engine air inlet.
A subsystem of the engine fuel system is formed by the fuel vapor generator, including the vapor collector which is connected in a circuit with the in-tank fuel pump, the pressure regulator and the return fuel line.
These and other features and advantages of the invention will be more fully understood from the following description of certain specific embodiments of the invention taken together with the accompanying drawings.
REFERENCES:
patent: 5875765 (1999-03-01), Norton
patent: 5934260 (1999-08-01), Gadkaree
patent: 6189518 (2001-02-01), Cooke
patent: 6279548 (2001-08-01), Reddy
patent: 6308119 (2001-10-01), Majkowski et al.
patent: 2002/0046740 (2002-04-01), Biesinger et al.
Dolinar Andrew M.
General Motors Corporation
Marra Kathryn A.
LandOfFree
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