US Patent No: 4,729,220

Number of patents in Portfolio can not be more than 2000

Air/fuel ratio control system for lean combustion engine using three-way catalyst

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Importance

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Abstract

The invention relates to a control system for feedback control of the air/fuel ratio in an internal combustion engine which uses a three-way catalyst to purify the exhaust gas, and which may be an automotive engine, by using an exhaust sensor to detect actual values of air/fuel ratio in the engine. The control system has the function of varying the target value of air/fuel ratio according to operating conditions of the engine such that the target value becomes super-stoichiometric at least in a portion of a steady zone of the engine operating conditions. The control system includes means to detect the temperature of the three-way catalyst and means to vary the feed of fuel or air to the engine when the catalyst temperature is above a predetermined level, e.g. 750.degree. C., while the target value of the air/fuel ratio is super-stoichiometric such that the actual air/fuel ratio decreases to a predetermined value, e.g. stoichiometric value, which is optimum for the activities of the three-way catalyst, or to a still lower value. Such intentional change in the air/fuel ratio under the high exhaust temperature condition is effective in preventing early deterioration of the three-way catalyst.

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First Claim

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Patent Owner(s)

Patent OwnerAddressTotal Patents
NISSAN MOTOR CO., LTD.YOKOHAMA9321

International Classification(s)

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  • [Patents Count]

Inventor(s)

Inventor Name Address # of filed Patents Total Citations
Saitoh, Makoto Saitama, JP 17 132
Terasaka, Katsunori Yokosuka, JP 6 146

Cited Art

Patent Info (Count) # Cites Year
 
ENGELHARD CORPORATION (1)
4,526,001 Method and means for controlling air-to-fuel ratio 15 1982
 
KABUSHIKI KAISHA TOYOTA CHUO KENKYUSHO (1)
4,617,794 Exhaust gas purifying method and apparatus for internal combustion engines 15 1985
 
NIPPONDENSO CO., LTD. (1)
4,319,451 Method for preventing overheating of an exhaust purifying device 34 1980
 
TOYOTA JIDOSHA KOGYO KABUSHIKI KAISHA (1)
4,376,369 Device for controlling primary and secondary air/fuel ratios for internal combustion engine 15 1980
 
YAMAHA HATSUDOKI KABUSHIKI KAISHA (1)
4,192,140 Apparatus and method relating to internal combustion engines utilizing an exhaust gas reactor 22 1974

Patent Citation Ranking

Forward Cites

Patent Info (Count) # Cites Year
 
TOYOTA JIDOSHA KABUSHIKI KAISHA (8)
5,201,802 Exhaust gas purification system for an internal combustion engine 125 1992
5,402,641 Exhaust gas purification apparatus for an internal combustion engine 127 1993
5,925,088 Air-fuel ratio detecting device and method 26 1996
5,777,204 Air-fuel ratio detecting device and method therefor 8 1997
5,834,624 Air-fuel ratio detecting device and method therefor 3 1997
6,158,212 Failure diagnosing device for exhaust gas purifying apparatus 13 1998
6,134,884 Air-fuel ratio control apparatus for internal combustion engine 4 1999
6,526,745 Internal combustion engine having a variable valve mechanism and control method therefor 48 2000
 
FORD GLOBAL TECHNOLOGIES, INC. (4)
5,431,012 System for monitoring the performance of automotive catalysts 11 1994
5,974,785 Closed loop bias air/fuel ratio offset to enhance catalytic converter efficiency 9 1997
5,941,211 Direct injection spark ignition engine having deceleration fuel shutoff 23 1998
6,272,850 Catalytic converter temperature control system and method 3 1998
 
NISSAN MOTOR CO., LTD. (3)
5,060,473 System for detecting deterioration of catalyst in catalytic converter 20 1989
5,060,474 Exhaust emission control failure detection system for internal combustion engine 17 1990
5,570,575 Fuel delivery control apparatus for use with internal combustion engine 18 1994
 
FORD GLOBAL TECHNOLOGIES, LLC (2)
7,143,574 System and method for determining set point location for oxidant-based engine air/fuel control strategy 1 2004
7,007,461 System and method for controlling catalyst storage capacity 3 2004
 
HONDA GIKEN KOGYO KABUSHIKI KAISHA (2)
5,158,063 Air-fuel ratio control method for internal combustion engines 43 1991
5,398,501 Air-fuel ratio control system for internal combustion engines 5 1993
 
ALTON GEOSCIENCE (1)
5,118,629 Vapor extraction technique 4 1988
 
CHRYSLER GROUP LLC (1)
5,802,844 After-burner heated catalyst system and associated control circuit and method 12 1995
 
DENSO CORPORATION (1)
7,930,879 Control device for internal combustion engine 0 2007
 
EMITEC GESELLSCHAFT FUER EMISSIONSTECHNOLOGIE MBH (1)
5,255,511 Method and apparatus for operational monitoring of a catalytic converter of an internal combustion engine and a catalytic converter to be monitored 38 1992
 
ENGELHARD CORPORATION (1)
6,021,638 Engine management strategy to improve the ability of a catalyst to withstand severe operating enviroments 17 1997
 
FERRARI S.P.A. (1)
5,107,432 System for protection of automotive exhaust gas combustion devices 4 1990
 
MAN TECHNOLOGIE GMBH (1)
4,953,351 Combustion control 15 1988
 
MAZDA MOTOR CORPORATION (1)
5,501,074 Exhaust gas purifying system 12 1994