Air-fuel ratio control device of an internal combustion engine
Transcript of Air-fuel ratio control device of an internal combustion engine
United States Patent [191 Matsuoka
5,074,113 Dec. 24, 1991
[11] Patent Number:
[45] Date of Patent:
[54] AIR-FUEL RATIO CONTROL DEVICE OF AN INTERNAL COMBUSTION ENGINE
[75] Inventor:
[73] Assignee: I-Iiroki Matsueka, Susono, Japan
Toyota Jidosha Kabushiki Kaisha, Japan
[21] Appl. No.: 541,830
[22] Filed: Jun. 21, 1990
[30] Foreign Application Priority Data 11111.23, 1989 [JP] Japan ................................ .. 1-161592
[51] 111:. c1; .............................................. .. FOlN 3/22
[52] US. Cl. . . . . . . . . . . . . . . . . . . . . . .. 60/276; 60/285
[58] Field of Search ........................ .. 60/276, 274, 285
[56] References Cited U.S. PATENT DOCUMENTS
4,263,782 4/1981 Matsumoto ......................... .. 60/276
4,383,515 5/1983 Higashiyama ...................... .. 60/276
4,522,180 6/1985 Matsuoka et al.. 4,696,274 9/1987 Sato.
FOREIGN PATENT DOCUMENTS
59-87241 5/1984 Japan . 59-87242 5/1984 Japan . 63-79448 5/1988 Japan . 63-79449 5/1988 Japan .
63-118354 7/1988 Japan . 63-119844 8/1988 Japan .
l-8332 l/1989 Japan .
Primary Examiner-Douglas Hart
Attorney, Agent, or Firm-—Oliff & Berridge
[57] ABSTRACT An air-fuel ratio control device comprising two main air-fuel ratio detecting sensors arranged in ?rst and second exhaust passages upstream of three-way cata lysts respectively for detecting an air-fuel ratio in the ?rst and second exhaust passages, an auxiliary air-fuel ratio detecting sensor for detecting an air-fuel ratio in at least a ?rst exhaust passage of the ?rst and second ex haust passages downstream of the three-way catalysts, a deviation detecting unit for detecting a mutual devia tion between the air-fuel ratios in the ?rst and second exhaust passages, a ?rst control value controlling unit for controlling a control value in at least the ?rst cylin der bank to which the ?rst exhaust passage is con nected, on the basis of the value detected by the auxil- _ iary air-fuel ratio detecting sensor, a second control value controlling unit for controlling a control value in at least the second cylinder bank on the basis of the deviation detected by the deviation detecting unit to cancel the deviation, a feedback correction coef?cient controlling unit for controlling the feedback correction coef?cients in the cylinder banks on the basis of the values detected by the corresponding main air-fuel ratio detecting sensors and the control values, and an air-fuel ratio control unit for controlling the air-fuel ratio in the ?rst and second exhaust passages by the corresponding feedback correction coef?cients to obtain a predeter mined air-fuel ratio.
25 Claims, 22 Drawing Sheets
US. Patent Dec. 24, 1991 Sheet 3 of 22 5,074,113
CALCULATION OF ' LFAF AND RFAF Fig 2
[READING OF DATA M02 F|g_2A FIQZB
304 cowmoNs FOR F'Q'ZC
EXECUTIONOFFEE FIQ'ZD
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US. Patent Dec. 24, 1991 Sheet 4 of 22 5,074,113
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US. Patent Dec. 24, 1991 ' Sheet 5 of 22 5,074,113
CONDITIONS FOR EXECUTION OF FEED
CONTROL STAN)
AIR-FUEL RATIO DETECTING SENSOR DETECTION SIGNAL
RIGHT CYLINDER BANK MAIN / RVI
426 1
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US. Patent Dec. 24, 1991 Sheet 10 of 22 5,074,113
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US. Patent Dec. 24, 1991 ' Sheet 11 of 22 5,074,113
Fig.5
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US. Patent Dec. 24, 1991 Sheet 12 of 22
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5,074,113
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( RETURN )
US. Patent Dec. 24, 1991 Sheet 13 of 22 5,074,113
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US. Patent Dec. 24, 1991
IL
Sheet 17 of 22 5,074,113
(FUEL INJECTION ) CONTROL I
A DATA READ IN A/ 1610 I
TAUO-KO£ xQ/Ne 1620
l
INCREASE COEFFICIENT I
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US. Patent Dec. 24, 1991 Sheet 18 01122 5,074,1'13
Fig.9
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COOLING WATER TEMPERATURE THW (°C)
US. Patent Dec. 24, 1991 Sheet 19 of 22 5,074,113
CALCULATION OF SKIP VALUE
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( RETURN )