US4745741A
Expired / Lapsed
US
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Double air-fuel ratio sensor system having improved response characteristics
Assignee: Toyota Motor Corp
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Filing: 1986-04-02
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Granted: 1988-05-24
•
Expires: 2006-04-02
Abstract
Abstract In a double air-fuel sensor system including two air-fuel ratio sensors upstream and downstream of a catalyst converter provided in an exhaust gas passage, an actual air-fuel ratio is adjusted in accordance with the outputs of the upstream-side air-fuel ratio sensor and the downstream-side air-fuel ratio sensor. The adjustment of the air-fuel ratio by the downstream-side air-fuel ratio sensor is stopped when the engine is in a predetermined state.
Inventors
- 👤 Takatoshi Masui
- 👤 Toshinari Nagai
- 👤 Toshiyasu Katsuno
- 👤 Yoshiki Chujo
- 👤 Nobuaki Kayanuma
- 👤 Hironori Bessho
- 👤 Yasushi Sato
- 👤 Toshio Tanahashi
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-28 18:23
CPC Classifications
F; F02; F02D; F02D41/00; F02D41/02; F02D41/14; F02D41/1438; F02D41/1439; F02D41/1441
Claims Analysis
Total Claims: 150
Claim 1
Independent Claim
150 words
A method for controlling the air-fuel ratio of an internal combustion engine having a catalyst converter for removing pollutants in the exhaust gas thereof, and upstream-side and downstream-side air-fuel ratio sensors disposed upstream and downstream, respectively, of said catalyst converter for detecting a concentration of a specific component in an exhaust gas, comprising the steps of: calculating a first air-fuel ratio correction amount in accordance with the output of said upstream-side air-fuel ratio sensor; calculating a second air-fuel ratio correction amount in accordance with the output of asid downstream-side air-fuel ratio sensor; adjusting the actual air-fuel ratio in accordance with said first and second air-fuel ratio correcton amounts; determining whether or not said engine is in a predetermined state; and prohibiting the calculation of said second air-fuel ratio correction amount while carrying out the calculation of said first air-fuel ratio correction amount when said engine is in said predetermined state.
Claim 2
Independent Claim
150 words
A method for controlling the air-fuel ratio of an internal combustion engine having a catalyst converter for removing pollutants in the exhaust gas thereof, and upstream-side and downstream-side air-fuel ratio sensors disposed upstream and downstream, respectively, of said catalyst converter for detecting a concentration of a specific component in an exhaust gas, comprising the steps of: calculating a first air-fuel ratio correction amount in accordance with the output of said upstream-side air-fuel ratio sensor; calculating a second air-fuel ratio correction amount in accordance with the output of asid downstream-side air-fuel ratio sensor; adjusting the actual air-fuel ratio in accordance with said first and second air-fuel ratio correcton amounts; determining whether or not said engine is in a predetermined state; and prohibiting the calculation of said second air-fuel ratio correction amount while carrying out the calculation of said first air-fuel ratio correction amount when said engine is in said predetermined state.
Claim 3
Dependent Claim
27 words
A method as set forth in claim 1, wherein said prohibiting step comprises a step of fixing said second air-fuel ratio correction amount at a predetermined value.
Claim 4
Dependent Claim
34 words
A method as set froth in claim 1, wherein said prohibiting step comprises a step of fixing said second air-fuel ratio correction amount at a value immediately before said engine enters said predetermined state.
Claim 5
Dependent Claim
35 words
A method as set forth in claim 1, wherein said prohibiting step comprises a step of fixing said second air-fuel ratio correction amount at a mean value when said engine is in said predetermined state.
Claim 6
Dependent Claim
69 words
A method as set forth in claim 1, wherein said engine state determining step comprises the steps of: determining whether or not said engine is in a lean air-fuel ratio requesting state; and switching an air-fuel ratio feedback control parameter for the output of said upstream-side air-fuel ratio sensor from a stoichiometric air-fuel ratio to a lean air-fuel ratio when said engine enters said lean air-fuel ratio requesting state.
Claim 7
Dependent Claim
31 words
A method as set forth in claim 5, wherein said lean air-fuel ratio requesting step comprises a step of determining whether or not said engine is in a small load state.
Claim 8
Dependent Claim
88 words
A method as set forth in claim 6, wherein said small load determining step comprises the steps of: determining whether or not a speed of said engine is smaller than a predetermined value; and determining whether or not the amount of fuel to be supplied to said engine is smaller than a predeterminined amount, thereby determining that said engine is in a small load state when the speed of said engine is smaller than said predetermined value and the amount of fuel is smaller than said predetermined amount.
Claim 9
Dependent Claim
67 words
A method as set forth in claim 5, wherein said air-fuel ratio feedback control parameter is determined by a rich delay time period for delaying the output of said upstream-side air-fuel ratio sensor switched from the lean side to the rich side and a lean delay time period for delaying the output of said upstream-side air-fuel ratio sensor switched from the rich side to the lean side.
Claim 10
Dependent Claim
87 words
A method as set forth in claim 5, wherein said air-fuel ratio feedback control parameter is determined by a rich skip amount by which said first air-fuel ratio correction amount is remarkably increased when the output of said upstream-side air-fuel ratio sensor is switched from the rich side to the lean side, and a lean skip amount by which said first air-fuel ratio correction amount is remarkably decreased when the output of said upstream-side air-fuel ratio sensor is switched from the lean side to the rich side.
Claim 11
Dependent Claim
77 words
A method as set forth in claim 5, wherein said air-fuel ratio feedback control parameter is dtermined by a rich integration amount by which said first air-fuel ratio correction amount is gradually incrased when the output fo said upstream-side air-fuel ratio sensor is on the lean side, and a lean integration amount by which said first air-fuel ratio correction amount is gradually decreased when the output of said upstream-side air-fuel ratio sensor is on the rich side.
Claim 12
Dependent Claim
49 words
A method as set forth in claim 5, wherein said air-fuel ratio feedback control parameter is determined by a reference voltage with which the output of said upstream-side air-fuel ratio sensor is comprared, thereby determining whether the air-fuel ratio is on the rich side or on the lean side.
Claim 13
Dependent Claim
63 words
A method as set forth in claim 1, wherein said engine state determining step comprises the steps of: detecting a change of said engine from a steady state to a transient state; and determining whether or not a predetermined duration has passed after said change is detected, thereby determining that said engine is in said predetermined state, before said predetermined duration has passed.
Claim 14
Dependent Claim
31 words
A method as set forth in claim 12, wherein said engine state-change detecting step comprises a step of determining whether or not a throttle valve of said engine is completely closed.
Claim 15
Dependent Claim
47 words
A method as set forth in claim 12, wherein said engine state-change detecting step comprises the steps of: calculating a change of an intake air amount of said engine; and determining whether o not the change of said intake air amount is larger than a predetermined amount.
Claim 16
Dependent Claim
47 words
A method as set forth in claim 12, wherein said engine state-change detecting step comprises the steps of: calculating a change of an intake air pressure of said engine; and determining whether or not the change of said intake air pressure is larger than a predetermined pressure.
Claim 17
Dependent Claim
45 words
A method as set forth in claim 12, wherein said engine state-change detecting step comprises the steps of: calculating a change of a throttling opening of said engine; and determining whether or not the change of said throttling opening is larger than a predetermined opening.
Claim 18
Dependent Claim
43 words
A method as set forth in claim 12, wherein said engine state-change detecting step comprises the steps of: calculating a change of a speed of said engine; and determining whether or not the change of said speed is larger than a predetermined value.
Claim 19
Dependent Claim
33 words
A method as set forth in claim 12, wherein said engine state-change detecting step comprises the steps of: calculating a change of a speed of a vehicle in which said engine is mounted;
Claim 20
Dependent Claim
16 words
determining whether or not the change of said vehicle speed is larger than a predetermined value.
Claim 21
Dependent Claim
16 words
determining whether or not the change of said vehicle speed is larger than a predetermined value.
Claim 22
Dependent Claim
29 words
A method as set forth in claim 12, wherein said engine state determining step comprises a step of determining whether or not said engine is in a deceleration state.
Claim 23
Dependent Claim
72 words
A method as set forth in claim 19, wherein said deceleration state determining step comprises the steps of: determining whether or not a throttle valve of said engine is completely closed; determining whether or not a speed of a vehicle in which said engine is mounted is zero, thereby determining that said engine is in a deceleration state when said throttle valve is completely closed and said vehicle speed is not zero.
Claim 24
Dependent Claim
80 words
A method as set forth in claim 19, wherein said deceleration state determining step comprises the steps of: determining whether or not an intake air amount of said engine is smaller than a predetermined amount; determining whether or not a speed of a vehicle in which said engine is mounted is zero, thereby determining that said engine is in a deceleration state when said intake air amount is smaller than said predetermined amount and said vehicle speed is not zero.
Claim 25
Dependent Claim
80 words
A method as set forth in claim 19, wherein said deceleration state determining step comprises the steps of: determining whether or not an intake air pressure of said engine is smaller than a predetermined pressure; determining whether or not a speed of a vehicle in which said engine is mounted is zero, thereby determining that said engine is in a deceleration state when said intake air pressure is smaller than said predetermined pressure and said vehicle speed is not zero.
Claim 26
Dependent Claim
79 words
A method as set forth in claim 19, wherein said deceleration state determining step comprises the steps of: determining whether or not a throttle valve opening of said engine is smaller than a predetermined; determining whether or not a speed of a vehicle in which said engine is mounted is zero, thereby determining that said engine is in a deceleration state when said throttle valve opening is smaller than said predetermined opening and said vehicle speed is not zero.
Claim 27
Dependent Claim
62 words
A method as set forth in claim 1, wherein said engine state determining step comprises the steps of: determining whether or not said engine is in an idling state; determining whether or not a predetermined duration of said idling state has passed, thereby determining that said engine is in said predetermined state after said predetermined duration of said idling state has passed.
Claim 28
Dependent Claim
73 words
A method as set forth in claim 24, wherein said idling state determining step comprises the steps of: determining whether or not a throttle valve of said engine is completely closed; and determining whether or not a speed of a vehicle in which said engine is mounted is zero, thereby determining that said engine is in an idling state when said throttle valve is completely closed and said vehicle speed is not zero.
Claim 29
Dependent Claim
82 words
A method as set for the in claim 24, wherein, in the case of an automatic transmission vehicle, said idling state determining step comprises the steps of: determining whether or not a neutral switch of the automatic transmission is turned ON; determining whether or not a speed of a vehicle in which said engine is mounted is zero, thereby determining that said engine is in an idling state when said neutral switch is turned ON and said vehicle speed is not zero.
Claim 30
Dependent Claim
82 words
A method as set forth in claim 24, wherein said idling state determining step comprises the steps of: determining whether or not an intake air amount of said engine is smaller than a predetermined amount; and determining whether or not a speed of said engine is smaller than a predetermined speed, thereby determining that said engine is in an idling state when said intake air amount is smaller than said predetermined amount and said engine speed is smaller than said predetermined speed.
Claim 31
Dependent Claim
82 words
A method as set forth in claim 24, wherein said idling state determining step comprises the steps of: determining whether or not an intake air pressure of said engine is smaller than a predetermined pressure; and determining whether or not a speed of said engine is smaller than a predetermined speed, thereby determining that said engine is in an idling state when said intake air pressure is smaller than said predetermined pressure and said engine speed is smaller than said predetermined speed.
Claim 32
Dependent Claim
82 words
A method as set forth in claim 24, wherein said idling state determining step comprises the steps of: determining whether or not a throttle valve opening of said engine is smaller than a predetermined opening; and determining whether or not a speed of said engine is smaller than a predetrmined speed, thereby determining that said engine is in an idling state when said throttle valve opening is smaller than said predetermined opening and said engine speed is smaller than said predetermined speed.
Claim 33
Dependent Claim
82 words
A method as set forth in claim 24, wherein said idling state determining step comprises the steps of: determining whether or not a speed of said engine is smaller than a predetermined speed; and determining whether or not an exhaust gas temperature of said engine is lower than a predetermined temperature, thereby determining that said engine is in an idling state when said engine speed is lower than said pedetermined speed and said exhaust gas temeprature is lower than said predetermined temperature.
Claim 34
Dependent Claim
79 words
A method as set forth in claim 24, wherein said idling state determining step comprises the steps of: determining whether or not a speed of said engine is smaller than a predetermined speed; and determining whether or not a coolant temperature of said engine is lower than a predetermined temperature, thereby determining that said engine is an idling state when said engine speed is lower than said predetermined speed and said coolant temperature is lower than said predetermined temperature.
Claim 35
Dependent Claim
87 words
A method as set forth in claim 24, wherein said idling state determining step comprises the steps of: determining whether or not a speed of said engine is smaller than a predetermined speed; and determining whether or not a temperature of said downstream-side air-fuel ratio sensor is lower than a predetermined temperature, thereby determining that said engine is in an idling state when said engine speed is lower than said predetermined speed and said temperature of said downstream-side air-fuel ratio sensor is lower than said predetermined temperature.
Claim 36
Dependent Claim
77 words
A method as set forth in claim 24, wherein said idling state determining step comprises the steps of: determining whether or not a throttle valve of said engine is completely closed; and determining whether or not an exhaust gas temperature of said engine is lower than a predetermined temperature, thereby determining that said engine is in an idling state when said throttle valve is completely closed and said exhaust gas temperature is lower than said predetermined temperature.
Claim 37
Dependent Claim
72 words
A method is set forth in claim 24, wherein said idling state determining steps of: determining whether or not a throttle valve of said engine is completely closed; and determining whether or not a coolant temperature of said engine is lower than a predetermined temperature, thereby determining that said engine is in an idling state when said throttle valve is completely closed and said coolant temperature is lower than said predetermined temperature.
Claim 38
Dependent Claim
82 words
A method as set forth in claim 24, wherein said idling state determining step comprises the steps of: determining whether or not a throttle valve of said engine is completely closed; and determining whether or not a temperature of said downstream-side air-fuel ratio sensor is lower than a predetermined temperature, thereby determining that said engine is in an idling state when said throttle valve is completely closed and said temperature of said downstream-side air-fuel ratio sensor is lower than said predetermined temperature.
Claim 39
Dependent Claim
37 words
A method as set forth in claim 1, further comprising a step of delaying the restart of the calculation of said second air-fuel ratio correction amount for a predetermined duration after said engine leaves said predetermined state.
Claim 40
Independent Claim
152 words
A method for controlling the air-fuel ratio in an internal combustion engine having a catalyst converter for removing pollutants in the exhaust gas thereof, and upstream-side and downstream-side air-fuel ratio sensors disposed upstream and downstream, respectively, of said catalysts converter for detecting a concentration of a specific component in an exhaust gas, comprising the steps of: calculating an air-fuel ratio correction amount in accordance with the output of said upstream-side air-fuel ratio sensor; calculating an air-fuel ratio feedback control parameter in accordance with the output of said downstream-side air-fuel ratio sensor; adjusting the actual air-fuel ratio in accordance with said air-fuel ratio feedback control parameter and said air-fuel ratio correction amount; determining whether or not said engine is in a predetermined state; and prohibiting the calculation of said air-fuel ratio feedback control parameter while carrying out the calculation of said air-fuel ratio correction amount when said engine is in said predetermined state.
Claim 41
Independent Claim
152 words
A method for controlling the air-fuel ratio in an internal combustion engine having a catalyst converter for removing pollutants in the exhaust gas thereof, and upstream-side and downstream-side air-fuel ratio sensors disposed upstream and downstream, respectively, of said catalysts converter for detecting a concentration of a specific component in an exhaust gas, comprising the steps of: calculating an air-fuel ratio correction amount in accordance with the output of said upstream-side air-fuel ratio sensor; calculating an air-fuel ratio feedback control parameter in accordance with the output of said downstream-side air-fuel ratio sensor; adjusting the actual air-fuel ratio in accordance with said air-fuel ratio feedback control parameter and said air-fuel ratio correction amount; determining whether or not said engine is in a predetermined state; and prohibiting the calculation of said air-fuel ratio feedback control parameter while carrying out the calculation of said air-fuel ratio correction amount when said engine is in said predetermined state.
Claim 42
Dependent Claim
27 words
A method as set forth in claim 37, wherein said prohibiting step comprises a step of fixing said air-fuel ratio feedback control parameter at a predetermined value.
Claim 43
Dependent Claim
34 words
A method as set forth in claim 37, wherein said prohibiting step comprises a step of fixing said air-fuel ratio feedback control parameter at a value immediately before said engine enters said predetermined state.
Claim 44
Dependent Claim
35 words
A method as set forth in claim 37, wherein said prohibiting step comprises a step of fixing said air-fuel ratio feedback control parameter at a mean value when said engine is in said predetermined state.
Claim 45
Dependent Claim
79 words
A method as set forth in claim 37, wherein said engine state determining step comprises the steps of: determining whether or not said engine is in a lean air-fuel ratio requesting state; and switching another an other air-fuel ratio feedback control parameter, different from said air-fuel ratio feedback control parameter, for the output of siad upstream-side air-fuel ratio sensor from a stoichiometric air-fuel ratio to a lean air-fuel ratio when said engine enters said lean air-fuel ratio requesting state.
Claim 46
Dependent Claim
31 words
A method as set forth in claim 41, wherein said lean air-fuel ratio requesting step comprises a step of determining whether or not said engine is in a small load state.
Claim 47
Dependent Claim
88 words
A method as set forth in claim 42, wherein said small load determining step comprises the steps of: determining whether or not a speed of said engine is smaller than a predetermined value; and determining whether or not the amount of fuel to be supplied to said engine is smaller than a predetermined amount, thereby determining that said engine is in a small load state when the speed of said engine is smaller than said predetermined value and the amount of fuel is smaller than said predetermined amount.
Claim 48
Dependent Claim
69 words
A method as set forth in claim 41, wherein one of said air-fuel ratio feedback control parameters is determined by a rich delay time period for delaying the output of said upstream-side airfuel ratio sensor switched from the lean side to the rich side and a lean delay time period for delaying the output of said upstream-side air-fuel ratio sensor switched from the rich side to the lean side.
Claim 49
Dependent Claim
88 words
A method as set forth in claim 41, wherein one of said air-fuel ratio feedback control parameters is determined by a rich skip amount by which said first air-fuel ratio correction amount is remarkably increased when the output of said upstreamside air-fuel ratio sensor is switched form the rich side to the lean side, and a lean amount by which said first air-fuel ratio correction amount is remarkably decreased when the output of said upstream-side air-fuel ratio sensor is switched from the lean side to the rich side.
Claim 50
Dependent Claim
79 words
A method as set forth in claim 41, wherein one of said air-fuel ratio feedback control parameters is determined by a rich integration amount by which said first air-fuel ratio correction amount is gradually increased when the output of said upstream-side air-fuel ratio sensor is on the lean side, and a lean integration amount by which said first air-fuel ratio correction amount is gradually decreased when the output of said upstream-side air-fuel ratio sensor is on the rich side.
Claim 51
Dependent Claim
51 words
A method as set forth in claim 41, wherein one of said air-fuel ratio feedback control parameters is determined by a reference voltage with which the output of said upstream-side air-fuel ratio sensor is compared, thereby determining whether the airfuel ratio is on the rich side or on the lean side.
Claim 52
Dependent Claim
63 words
A method as set forth in claim 37, wherein said engine state determining step comprises the steps of: detecting a change of said engine from a steady state to a transient state; and determining whether or not a predetermined duration has passed after said change is detected, thereby determining that said engine is in said predetermined state, before said predetermined duration has passed.
Claim 53
Dependent Claim
31 words
A method as set forth in claim 48, wherein said engine state-change detecting step comprises a step of determining whether or not a throttle valve of said engine is completely closed.
Claim 54
Dependent Claim
47 words
A method as set forth in claim 48, wherein said engine state-change detecting step comprises the steps of: calculating a change of an intake air amount of said engine; and determining whether or not the change of said intake air amount is larger than a predetermined amount.
Claim 55
Dependent Claim
48 words
A method as set forth in claim 48, wherein said engine state change detecting step comprises the steps of: calculating a change of an intake air pressure of said engine; and determining whether or not the change of said intake air pressure is larger than a predetermined pressure.
Claim 56
Dependent Claim
45 words
A method as set forth in claim 48, wherein said engine state-change detecting step comprises the steps of: calculating a change of a throttling opening of said engine; and determining whether or not the change of said throttling opening is larger than a predetermined opening.
Claim 57
Dependent Claim
45 words
A method as set forth in claim 48, wherein said engine state-change detecting step comprises the steps of: calculating a change of a speed of said engine; and determining whether or not the change of said speed air amount is larger than a predetermined value.
Claim 58
Dependent Claim
49 words
A method as set forth in claim 48, wherein said engine state-change detecting step comprises the steps of: calculating a change of a speed of a vehicle in which said engine is mounted; determining whether or not the change of said vehicle speed is larger than a predetermined value.
Claim 59
Dependent Claim
29 words
A method as set forth in claim 37, wherein said engine state determining step comprises a step of determining whether or not said engine is in a deceleration state.
Claim 60
Dependent Claim
72 words
A method as set forth in claim 55, wherein said deceleration state determining step comprises the steps of: determining whether or not a throttle valve of said engine is completely closed; determining whether or not a speed of a vehicle in which said engine is mounted is zero, thereby determining that said engine is in a deceleration state when said throttle valve is completely closed and said vehicle speed is not zero.
Claim 61
Dependent Claim
80 words
A method as set forth in claim 55, wherein said deceleration state determining step comprises the steps of: determining whether or not an intake air amount of said engine is smaller than a predetermined amount; determining whether or not a speed of a vehicle in which said engine is mounted is zero, thereby determining that said engine is in a deceleration state when said intake air amount is smaller than said predetermined amount and said vehicle speed is not zero.
Claim 62
Dependent Claim
80 words
A method as set forth in claim 55, wherein said deceleration state determining step comprises the steps of: determining whether or not an intake air pressure of said engine is smaller than a predetermined pressure; determining whether or not a speed of a vehicle in which said engine is mounted is zero, thereby determining that said engine is in a deceleration state when said intake air pressure is smaller than said predetermined pressure and said vehicle speed is not zero.
Claim 63
Dependent Claim
78 words
A method as set forth in claim 55, wherein said deceleration state determining step comprises the steps of: determining whether or not a throttle valve opening of said engine is smaller than a predetermined opening; determining whether or not a speed vehicle in which said engine is mounted is zero, thereby determining that said engine is in a deceleration state when said throttle valve opening is smaller than said predetermined opening and said vehicle speed is not zero.
Claim 64
Dependent Claim
62 words
A method as set forth in claim 37, wherein said engine state determining step comprises the steps of: determining whether or not said engine is in an idling state; determining whether or not a predetermined duration of said idling state has passed, thereby determining that said engine is in said predetermined state after said predetermined duration of said idling state has passed.
Claim 65
Dependent Claim
73 words
A method as set forth in claim 60, wherein said idling state determining step comprises the steps of: determining whether or not a throttle valve of said engine is completely closed; and determining whether or not a speed of a vehicle in which said engine is mounted is zero, thereby determining that said engine is in an idling state when said throttle valve is completely closed and said vehicle speed is not zero.
Claim 66
Dependent Claim
81 words
A method as set forth in claim 60, wherein, in the case of an automatic transmission vehicle, said idling state determining step comprises the steps of: determining whether or not a neutral switch of the automatic transmission is turned ON; determining whether or not a speed of a vehicle in which said engine is mounted is zero, thereby determining that said engine is in an idling state when said neutral switch is turned ON and said vehicle speed is not zero.
Claim 67
Dependent Claim
82 words
A method as set forth in claim 60, wherein said idling state determining step comprises the steps of: determining whether or not an intake air amount of said engine is smaller than a predetermined amount; and determining whether or not a speed of said engine is smaller than a predetermined speed, thereby determining that said engine is in an idling state when said intake air amount is smaller than said predetermined amount and said engine speed is smaller than said predetermined speed.
Claim 68
Dependent Claim
82 words
A method as set forth in claim 60, wherein said idling state determining step comprises the steps of: determining whether or not an intake air pressure of said engine is smaller than a predetermined pressure; and determining whether or not a speed of said engine is smaller than a predetermined speed, thereby determining that said engine is in an idling state when said intake air pressure is smaller than said predetermined pressure and said engine speed is smaller than said predetermined speed.
Claim 69
Dependent Claim
82 words
A method as set forth in claim 60, wherein said idling state determining step comprises the steps of: determining whether or not a throttle valve opening of said engine is smaller than a predetermined opening; and determining whether or not a speed of said engine is smaller than a predetermined speed, thereby determining that said engine is in an idling state when said throttle valve opening is smaller than said predetermined opening and said engine speed is smaller than said predetermined speed.
Claim 70
Dependent Claim
82 words
A method as set forth in claim 60, wherein said idling state determining step comprises the steps of: determining whether or not a speed of said engine is smaller than a predetermined speed; and determining whether or not an exhaust gas temperature of said engine is lower than a predetermined temperature, thereby determining that said engine is in an idling state when said engine speed is lower than said predetermined speed and said exhaust gas temperature is lower than said predetermined temperature.
Claim 71
Dependent Claim
80 words
A method as set forth in claim 60, wherein said idling state determining step compries the steps of: determining whether or not a speed of said engine is smaller than a predetermined speed; and determining whether or not a coolant temperature of said engine is lower than a predetermined temperature; thereby determining that said engine is in an idling state when said engine speed is lower than said predetermined speed and said coolant temperature is lower than said predetermined temperature.
Claim 72
Dependent Claim
86 words
A method as set forth in claim 60, wherein said idling state determining step comprises the steps of: determining whether or not a speed of said engine is smaller than a predetermined speed; and determining whether or not a temperature of said downstream-side air-fuel ratio sensor is lower than a predetermined temperature; thereby determining that said engine is in an idling state when said speed is lower than said predetermined speed and said temperature of said downstream-side air-fuel ratio sensor is lower than said predetermined temperature.
Claim 73
Dependent Claim
77 words
A method as set forth in claim 60, wherein said idling state determining step comprises the steps of: determining whether or not a throttle valve of said engine is completely closed; and determining whether or not an exhaust gas temperature of said engine is lower than a predetermined temperature; thereby determining that said engine is in an idling state when said throttle valve is completely closed and said exhaust gas temperature is lower than said predetermined temperature.
Claim 74
Dependent Claim
75 words
A method as set forth in claim 60, wherein said idling state determining step comprises the steps of: determining whether or not a throttle valve of said engine is completely closed; and determining whether or not a coolant temperature of said engine is lower than a predetermined temperature; thereby determining that said engine is in an idling state when said throttle valve is completely closed and said coolant temperature is lower than said predetermined temperature.
Claim 75
Dependent Claim
82 words
A method as set forth in claim 60, wherein said idling state determining step comprises the steps of: determining whether or not a throttle valve of said engine is completely closed; and determining whether or not a temperature of sasid downstream-sie air-fuel ratio sensor is lower than a predetermined temperature; thereby determining that said engine is in an idling state when said throttle valve is completely closed and said temperature of said downstream-side air-fuel ratio sensor is lower than said predetermined temperature.
Claim 76
Dependent Claim
37 words
A method as set forth in claim 37, further comprising a step of delaying the restart of the calculation of said second air-fuel ratio correction amount for a predetermined duration after said engine leaves said predetermined state.
Claim 77
Independent Claim
157 words
An apparatus for controlling the air-fuel ratio in an internal combustion engine having a catalyst converter for removing pollutants in the exhaust gas thereof, and upstream-side and downstream-side air-fuel ratio sensors disposed upstream and downstream, respectively, of said catalyst converter for detecting a concentration of a specific component in an exhaust gas, comprising: means for calculating a first air-fuel ratio correction amount in accordance with the output of said upstream-side air-fuel ratio sensor; means for calculating a second air-fuel ratio correction amount in accordance with the output of said downstream-side air-fuel ratio sensor; means for adjusting the actual air-fuel ratio in accordance with said first and second air-fuel ratio correction amounts; means for determining whether or not said engine is in a predetermined state; and means for prohibiting the calculation of said second air-fuel ratio correction amount while carrying out the calculation of said first air-fuel ratio correction amount when said engine is in said predetermined state.
Claim 78
Independent Claim
157 words
An apparatus for controlling the air-fuel ratio in an internal combustion engine having a catalyst converter for removing pollutants in the exhaust gas thereof, and upstream-side and downstream-side air-fuel ratio sensors disposed upstream and downstream, respectively, of said catalyst converter for detecting a concentration of a specific component in an exhaust gas, comprising: means for calculating a first air-fuel ratio correction amount in accordance with the output of said upstream-side air-fuel ratio sensor; means for calculating a second air-fuel ratio correction amount in accordance with the output of said downstream-side air-fuel ratio sensor; means for adjusting the actual air-fuel ratio in accordance with said first and second air-fuel ratio correction amounts; means for determining whether or not said engine is in a predetermined state; and means for prohibiting the calculation of said second air-fuel ratio correction amount while carrying out the calculation of said first air-fuel ratio correction amount when said engine is in said predetermined state.
Claim 79
Dependent Claim
26 words
An apparatus as set forth in claim 73, wherein said prohibiting means comprises means for fixing said second air-fuel ratio correction amount at a predetermined value.
Claim 80
Dependent Claim
33 words
An apparatus as set forth in claim 73, wherein said prohibiting means comprises means for fixing said second air-fuel ratio correction amount at a value immediately before said engine enters said predetermined state.
Claim 81
Dependent Claim
34 words
An apparatus as set forth in claim 73, wherein said prohibiting means comprises means for fixing said second air-fuel ratio correction amount at a mean value when said engine is in said predetermined state.
Claim 82
Dependent Claim
70 words
An apparatus as set forth in claim 73, wherein said engine state determining means comprises: means for determining whether or not said engine is in a lean air-fuel ratio requesting state; and means for switching an air-fuel ratio feedback control parameter for the output of said upstream-side air-fuel ratio sensor from a stoichiometric air-fuel ratio to a lean air-fuel ratio when said engine enters said lean air-fuel ratio requesting state.
Claim 83
Dependent Claim
30 words
An apparatus as set forth in claim 77, wherein said lean air-fuel ratio requesting means comprises means for determining whether or not said engine is in a small load state.
Claim 84
Dependent Claim
89 words
An apparatus as set forth in claim 78, wherein said small load determining means comprises: means for determining whether or not a speed of said engine is smaller than a predetermined value; and means for determining whether or not the amount of fuel to be supplied to said engine is smaller than a predetermined amount; thereby determining that said engine is in a small load state when the speed of said engine is smaller than said predetermined value and the amount of fuel is smaller than said predetermined amount.
Claim 85
Dependent Claim
67 words
An apparatus as set forth in claim 77, wherein said air-fuel ratio feedback control parameter is determined by a rich delay time period for delaying the output of said upstream-side air-fuel ratio sensor switched from the lean side to the rich side and a lean delay time period for delaying the output of said upstream-side air-fuel ratio sensor switched from the rich side to the lean side.
Claim 86
Dependent Claim
87 words
An apparatus as set forth in claim 77, wherein said air-fuel ratio feedback control parameter is determined by a rich skip amount by which said first air-fuel ratio correction amount is remarkably increased when the output of said upstream-side air-fuel ratio sensor is switched from the rich side to the lean side, and a lean skip amount by which said first air-fuel ratio correction amount is remarkably decreased when the output of said upstream-side air-fuel ratio sensor is switched from the lean side to the rich side.
Claim 87
Dependent Claim
77 words
An apparatus as set forth in claim 77, wherein said air-fuel ratio feedback control parameter is determined by a rich integration amount by which said first air-fuel ratio correction amount is gradually increased when the output of said upstream-side air-fuel ratio sensor is on the lean side, and a lean integration amount by which said first air-fuel ratio correction amount is gradually decreased when the output of said upstream-side air-fuel ratio sensor is on the rich side.
Claim 88
Dependent Claim
49 words
An apparatus as set forth in claim 77, wherein said air-fuel ratio feedback control parameter is determined by a reference voltage with which the output of said upstream-side air-fuel ratio sensor is compared, thereby determining whether the air-fuel ratio is on the rich side or on the lean side.
Claim 89
Dependent Claim
64 words
An apparatus as set forth in claim 73, wherein said engine state determining step comprises: means for detecting a change of said engine from a steady state to a transient state; and means for determining whether or not a predetermined duration has passed after said change is detected; thereby determining that said engine is in said predetermined state, before said predetermined duration has passed.
Claim 90
Dependent Claim
30 words
An apparatus as set forth in claim 84, wherein said engine state-change detecting means comprises means for determining whether or not a throttle valve of said engine is completely closed.
Claim 91
Dependent Claim
48 words
An apparatus as set forth in claim 84, wherein said engine state-change detecting means comprises: means for calculating a change of an intake our amount of said engine; and means for determining whether or not the change of said intake air amount is larger than a predetermined amount.
Claim 92
Dependent Claim
48 words
An apparatus as set forth in claim 84, wherein said engine state-change detecting means comprises: means for calculating a change of an intake air pressure of said engine; and means for determining whether or not the change of said intake air pressure is larger than a predetermined pressure.
Claim 93
Dependent Claim
46 words
An apparatus as set forth in claim 84, wherein said engine state-change detecting means comprises: means for calculating a change of a throttling opening of said engine; and means for determining whether or not the change of said throttling opening is larger than a predetermined opening.
Claim 94
Dependent Claim
44 words
An apparatus as set forth in claim 84, wherein said engine state-change detecting means comprises: means for calculating a change of a speed of said engine; and means for determining whether or not the change of said speed is larger than a predetermined value.
Claim 95
Dependent Claim
48 words
An apparatus as set forth in claim 84, wherein said engine state-change detecting means comprises: means for calculating a change of a speed of a vehicle on which said engine is mounted; for determining whether not the change of said vehicle speed is larger than a predetermined value.
Claim 96
Dependent Claim
28 words
An apparatus as set forth in claim 73, wherein said engine state determining means comprises means for determining whether or not said engine is in a deceleration state.
Claim 97
Dependent Claim
73 words
An apparatus as set forth in claim 91, wherein said deceleration state determining means comprises: means for determining whether or not a throttle valve of said engine is completely closed; means for determining whether or not a speed of a vehicle in which said engine is mounted is zero; thereby determining that said engine is in a deceleration state when said throttle valve is completely closed and said vehicle speed is not zero.
Claim 98
Dependent Claim
81 words
An apparatus as set forth in claim 91, wherein said deceleration state determining menas comprises: means for determining whether or not an intake air amount of said engine is smaller than a predetermined amount; means for determining whether or not a speed of a vehicle in which said engine is mounted is zero; thereby determining that said engine is in a deceleration state when said intake air amount is smaller than said predetermined amount and said vehicle speed is not zero.
Claim 99
Dependent Claim
81 words
An apparatus as set forth in claim 91, wherein said deceleration state determining means comprises: means for determining whether or not an intake air pressure of said engine is smaller than a predetermined pressure; means for determining whether or not a speed of a vehicle in which said engine is mounted is zero; thereby determining that said engine is in a deceleration state when said intake air pressure is smaller than said predetermined pressure and said vehicle speed is not zero.
Claim 100
Dependent Claim
80 words
An apparatus as set forth in claim 91, wherein said deceleration state determining means comprises: means for determining whether or not a throttle valve opening of said engine is smaller than a predetermined; means for determining whether or not a speed of a vehicle in which said engine is mounted is zero; thereby determining that said engine is in a deceleration state when said throttle valve opening is smaller than said predetermined opening and said vehicle speed is not zero.
Claim 101
Dependent Claim
63 words
An apparatus as set forth in claim 73, wherein said engine state determining means comprises: means for determining whether or not said engine is in an idling state; means for determining whether or not a predetermined duration of said idling state has passed; thereby determining that said engine is in said predetermined state after said predetermined duration of said idling state has passed.
Claim 102
Dependent Claim
74 words
An apparatus as set forth in claim 96, wherein said idling state determining means comprises: means for determining whether or not a throttle valve of said engine is completely closed; and means for determining whether or not a speed of a vehicle in which said engine is mounted is zero; thereby determining that said engine is in an idling state when said throttle valve is completely closed and said vehicle speed is not zero.
Claim 103
Dependent Claim
82 words
An apparatus as set forth in claim 96, wherein said idling state determining means comprises: means for determining whether or not a neutral switch of the automatic transmission is turned ON in the case of an automatic transmission vehicle; means for determining whether or not a speed of a vehicle in which said engine is mounted is zero; thereby determining that said engine is in an idling state when said neutral switch is turned ON and said vehicle speed is not zero.
Claim 104
Dependent Claim
86 words
An apparatus as set forth in claim 96, wherein said idling state determining means comprises the steps of: means for determining whether or not an intake air amount of said engine is smaller than a predetermined amount; and means for determining whether or not a speed of said engine is smaller than a predetermined speed, thereby determining that said engine is in an idling state when said intake air amount is smaller than said predetermined amount and said engine speed is smaller than said predetermined speed.
Claim 105
Dependent Claim
83 words
An apparatus as set forth in claim 96, wherein said idling state determining means comprises: means for determining whether or not an intake air pressure of said engine is smaller than a predetermined pressure; and means for determining whether or not a speed of said engine is smaller than a predetermined speed; thereby determining that said engine is in an idling state when said intake air pressure is smaller than said predetermined pressure and said engine speed is smaller than said predetermined speed.
Claim 106
Dependent Claim
83 words
An apparatus as set forth in claim 96, wherein said idling state determining means comprises: means for determining whether or not a throttle valve opening of said engine is smaller than a predetermined opening; and means for determining whether or not a speed of said engine is smaller than a predetermined speed; thereby determining that said engine is in a idling state when said throttle valve opening is smaller than said predetermined opening and said engine speed is smaller than said predetermined speed.
Claim 107
Dependent Claim
83 words
An apparatus as set forth in claim 96, wherein said idling state determining means comprises: means for determining whether or not a speed of said engine is smaller than a predetermined speed; and means for determining whether or not an exhaust gas temperature of said engine is lower than a predetermined temperature; thereby determining that said engine is in an idling state when said engine speed is lower than said predetermined speed and said exhaust gas temperature is lower than said predetermined temperature.
Claim 108
Dependent Claim
81 words
An apparatus as set forth in claim 96, wherein said idling state determining means comprises: means for determining whether or not a speed of said engine is smaller than a predetermined speed; and means for determining whether or not a coolant temperature of said engine is lower than a predetermined temperature; thereby determining that said engine is in an idling state when said engine speed is lower than said predetermined speed and said coolant temperature is lower than said predetermined temperature.
Claim 109
Dependent Claim
88 words
An apparatus as set forth in claim 96, wherein said idling state determining means comprises: means for determining whether or not a speed of said engine is smaller than a predetermined speed; and means for determining whether or not a temperature of said downstream-side air-fuel ratio sensor is lower than a predetermined temperature; thereby determining that said engine is in an idling state when said engine speed is lower than said predetermined speed and said temperature of said downstream-side air-fuel ratio sensor is lower than said predetermined temperature.
Claim 110
Dependent Claim
78 words
An apparatus as set forth in claim 96, wherein said idling state determining means comprises: means for determining whether or not a throttle valve of said engine is completely closed; and means for determining whether or not an exhaust gas temperature of said engine is lower than a predetermined temperature; thereby determining that said engine is in an idling state when said throttle valve is completely closed and said exhaust gas temperature is lower than said predetermined temperature.
Claim 111
Dependent Claim
76 words
An apparatus as set forth in claim 96, wherein said idling state determining means comprises: means for determining whether or not a throttle valve of said engine is completely closed; and means for determining whether or not a coolant temperature of said engine is lower than a predetermined temperature; thereby determining that said engine is in an idling state when said throttle valve is completely closed and said coolant temperature is lower than said predetermined temperature.
Claim 112
Dependent Claim
83 words
An apparatus as set forth in claim 96, wherein said idling state determining means comprises: means for determining whether or not a throttle valve of said engine is completely closed; and means for determining whether or not a temperature of said downstream-side air-fuel ratio sensor is lower than a predetermined temperature; thereby determining that said engine is in an idling state when said throttle valve is completely closed and said temperature of said downstream-side air-fuel ratio sensor is lower than said predetermined temperature.
Claim 113
Dependent Claim
37 words
An apparatus as set forth in claim 73, further comprising a means for delaying the restart of the calculation of said second air-fuel ratio correction amount for a predetermined duration after said engine leaves said predetermined state.
Claim 114
Independent Claim
159 words
A method for controlling the air-fuel ratio in an internal combustion engine having a catalyst converter for removing pollutants in the exhaust gas thereof, and upstream-side and downstream-side air-fuel ratio sensors disposed upstream and downstream, respectively, of said catalyst converter for detecting a concentration of a specific component in an exhaust gas, comprising: means for calculating an air-fuel ratio correction amount in accordance with the output of said upstream-side air-fuel ratio sensor; means for calculating an air-fuel ratio feedback control parameter in accordance with the output of said downstream-side air-fuel ratio sensor; means for adjusting the actual air-fuel ratio in accordance with said air-fuel ratio feedback control parameter and said air-fuel ratio correction amount; means for determining whether or not said engine is in a predetermined state; and means for prohibiting the calcualtion of said air-fuel ratio feedback control parameter while carrying out the calculation of said air-fuel ratio correction amount when said engine is in said predetermined state.
Claim 115
Independent Claim
159 words
A method for controlling the air-fuel ratio in an internal combustion engine having a catalyst converter for removing pollutants in the exhaust gas thereof, and upstream-side and downstream-side air-fuel ratio sensors disposed upstream and downstream, respectively, of said catalyst converter for detecting a concentration of a specific component in an exhaust gas, comprising: means for calculating an air-fuel ratio correction amount in accordance with the output of said upstream-side air-fuel ratio sensor; means for calculating an air-fuel ratio feedback control parameter in accordance with the output of said downstream-side air-fuel ratio sensor; means for adjusting the actual air-fuel ratio in accordance with said air-fuel ratio feedback control parameter and said air-fuel ratio correction amount; means for determining whether or not said engine is in a predetermined state; and means for prohibiting the calcualtion of said air-fuel ratio feedback control parameter while carrying out the calculation of said air-fuel ratio correction amount when said engine is in said predetermined state.
Claim 116
Dependent Claim
26 words
An apparatus as set forth in claim 109, wherein said prohibiting means comprises means for fixing said air-fuel ratio feedback control parameter at a predetermined value.
Claim 117
Dependent Claim
33 words
An apparatus as set forth in claim 109, wherein said prohibiting means comprises means for fixing said air-fuel ratio feedback control parameter at a value immediately before said engine esters said predetermined state.
Claim 118
Dependent Claim
34 words
An apparatus as set forth in claim 109, wherein said prohibiting means comprises means for fixing said air-fuel ratio feedback control parameter at a mean value when said engine is in said predetermined state.
Claim 119
Dependent Claim
78 words
An apparatus as set forth in claim 109, wherein said engine state determining means comprises: means for determining whether or not said engine is in a lean air-fuel ratio requesting state; and means for switching other air-fuel ratio feedback control parameters, different from said air-fuel ratio feedback control parameter, for the output of said upstream-side air-fuel ratio sensor from a stoichiometric air-fuel ratio to a lean air-fuel ratio when said engine enters said lean air-fuel ratio requesting state.
Claim 120
Dependent Claim
30 words
An apparatus as set forth in claim 113, wherein said lean air-fuel ratio requesting means comprises means for determining whether or not said engine is in a small load state.
Claim 121
Dependent Claim
89 words
An apparatus as set forth in claim 114, wherein said small load determining means comprises: means for determining whether or not a speed of said engine is smaller than a predetermined value; and means for determining whether or not the amount of fuel to be supplied to said engine is smaller than a predetermined amount, thereby determining that said engine is in a small load state when the speed of said engine is smaller than said predetermined value and the amount of fuel is smaller than said predetermined amount.
Claim 122
Dependent Claim
69 words
An apparatus as set forth in claim 113, wherein one of said air-fuel ratio feedback control parameters is determined by a rich delay time period for delaying the output of said upstream-side air-fuel ratio sensor switched from the lean side to the rich side and a lean delay time period for delaying the output of said upstream-side air-fuel ratio sensor switched from the rich side to the lean side.
Claim 123
Dependent Claim
89 words
An apparatus as set forth in claim 113, wherein one of said air-fuel ratio feedback control parameters is determined by a rich skip amount by which said first air-fuel ratio correction amount is remarkably increased when the output of said upstream-side air-fuel ratio sensor is switched from the rich side to the leam side, and a lean skip amount by which said first air-fuel ratio correction amount is remarkably decreased when the output of said upstream-side air-fuel ratio sensor is switched from the lean side to the rich side.
Claim 124
Dependent Claim
79 words
An apparatus as set forth in claim 113, wherein one of said air-fuel ratio feedback control parameters is determined by a rich integration amount by which said first air-fuel ratio correction amount is gradually increased when the output of said upstream-side air-fuel ratio sensor is on the leam side, and a lean integration amount by which said first air-fuel ratio correction amount is gradually decreased when the output of said upstream-side air-fuel ratio sensor is on the rich side.
Claim 125
Dependent Claim
51 words
An apparatus as set forth in claim 113, wherein one of said air-fuel ratio feedback control parameters is determined by a reference voltage with which the output of said upstream-side air-fuel ratio sensor is compared, thereby determining whether the air-fuel ratio is on the rich side or on the lean side.
Claim 126
Dependent Claim
64 words
An apparatus as set forth in claim 109, wherein said engine state determining means comprises: means for detecting a change of said engine from a steady state to a transient state; and means for determining whether or not a predetermined duration has passed after said change is detected, thereby determining that said engine is in said predetermined state, before said predetermined duration has passed.
Claim 127
Dependent Claim
30 words
An apparatus as set forth in claim 120, wherein said engine state-change detecting means comprises means for determining whether or not a throttle valve of said engine is completely closed.
Claim 128
Dependent Claim
48 words
An apparatus as set forth in claim 120, wherein said engine state-change detecting means comprises: means for calculating a change of an intake air amount of said engine; and means for determining whether or not the change of said intake air amount is larger than a predetermined amount.
Claim 129
Dependent Claim
47 words
An apparatus as set forth in claim 120, wherein said engine state-change detecting means comprises: means for calculating a change of an intake pressure of said engine; and means for determining whether or not the change of said intake air pressure is larger than a predetermined pressure.
Claim 130
Dependent Claim
46 words
An apparatus as set forth in claim 120, wherein said engine state-change detecting means comprises: means for calculating a change of a throttling opening of said engine; and means for determining whether or not the change of said throttling opening is larger than a predetermined opening.
Claim 131
Dependent Claim
46 words
An apparatus as set forth in claim 120, wherein said engine state-change detecting means comprises: means for calculating a change of an speed of said engine; and means for determining whether or not the change of said speed air amount is larger than a predetermined value.
Claim 132
Dependent Claim
50 words
An apparatus as set forth in claim 120, wherein said engine state-change detecting means comprises: means for calculating a change of a speed of a vehicle in which said engine is mounted; means for determining whether or not the change of said vehicle speed is larger than a predetermined value.
Claim 133
Dependent Claim
28 words
An apparatus as set forth in claim 109, wherein said engine state determining means comprises means for determining whether or not said engine is in a deceleration state.
Claim 134
Dependent Claim
73 words
An apparatus as set forth in claim 127, wherein said deceleration state determining means comprises: means for determining whether or not a throttle valve of said engine is completely closed; means for determining whether or not a speed of a vehicle in which said engine is mounted is zero, thereby determining that said engine is in a deceleration state when said throttle valve is completely closed and said vehicle speed is not zero.
Claim 135
Dependent Claim
81 words
An apparatus as set forth in claim 127, wherein said deceleration state determining means comprises: means for determining whether of not an intake air amount of said engine is smaller than a predetermined amount; means for determining whether or not a speed of a vehicle in which said engine is mounted is zero, thereby determining that said engine is in a deceleration state when said intake air amount is smaller than said predetermined amount and said vehicle speed is not zero,
Claim 136
Dependent Claim
81 words
A method as set forth in claim 127, wherein said deceleration state determining means comprises: means for determining whether or not an intake air pressure of said engine is smaller than a predetermined pressure; means for determining whether or not a speed of a vehicle in which said engine is mounted is zero, thereby determining that said engine is in a deceleration state when said intake air pressure is smaller than said predetermined pressure and said vehicle speed is not zero.
Claim 137
Dependent Claim
81 words
An apparatus as set forth in claim 127, wherein said deceleration state determining means comprises: means for determining whether or not a throttle valve opening of said engine is smaller than a predetermined opening; means for determining whether or not a speed of a vehicle in which said engine is mounted is zero, thereby determining that said engine is in a deceleration state when said throttle valve opening is smaller than said predetermined opening and said vehicle speed is not zero.
Claim 138
Dependent Claim
63 words
An apparatus as set forth in claim 109, wherein said engine state determining means comprises: means for determining whether or not said engine is in an idling state; means for determining whether or not a predetermined duration of said idling state has passed, thereby determining that said engine is in said predetermined state after said predetermined duration of said idling state has passed.
Claim 139
Dependent Claim
74 words
An apparatus as set forth in claim 132, wherein said idling state determining means comprises: means for determining whether or not a throttle valve of said engine is completely closed; and means for determining whether or not a speed of a vehicle in which said engine is mounted is zero, thereby determining that said engine is in an idling state when said throttle valve is completely closed and said vehicle speed is not zero.
Claim 140
Dependent Claim
82 words
An apparatus as set forth in claim 132, wherein said idling state determining means comprises: means for determining whether or not a neutral switch of the automatic transmission is turned ON, in the case of an automatic transmission vehicle; means for determining whether or not a speed of a vehicle in which said engine is mounted is zero, thereby determining that said engine is in an idling state when said newtral switch is turned ON and said vehicle speed is not zero.
Claim 141
Dependent Claim
83 words
An apparatus as set forth in claim 132, wherein said idling state determining means comprises: means for determining whether or not an intake air amount of said engine is smaller than a predetermined amount; and means for determining whether or not a speed of said engine is smaller than a predetermined speed, thereby determining that said engine is in an idling state when said intake air amount is smaller than said predetermined amount and said engine speed is smaller than said predetermined speed.
Claim 142
Dependent Claim
83 words
An apparatus as set forth in claim 132, wherein said idling state determining means comprises: means for determining whether or not an intake air pressure of said engine is smaller than a predetermined pressure; and means for determining whether or not a speed of said engine is smaller than a predetermined speed, thereby determining that said engine is in an idling state when said intake air pressure is smaller than said predetermined pressure and said engine speed is smaller than said predetermined speed.
Claim 143
Dependent Claim
83 words
An apparatus as set forth in claim 132, wherein said idling state determining means comprises: means for determining whether or not a throttle valve opening of said engine is smaller than a predetermined opening; and means for determining whether or not a speed of said engine is smaller than a predetermined speed, thereby determining that said engine is in an idling state when said throttle valve opening is smaller than said predetermined opening and said engine speed is smaller than said predetermined speed.
Claim 144
Dependent Claim
83 words
An apparatus as set forth in claim 132, wherein said idling state determining means comprises: means for determining whether or not a speed of said engine is smaller than a predetermined speed; and means for determining whether or not an exhaust gas temperature of said engine is lower than a predetermined temperature, thereby determining that said engine is in an idling state when said engine speed is lower than said predetermined speed and said exhaust gas temperature is lower than said predetermined temperature.
Claim 145
Dependent Claim
81 words
An apparatus as set forth in claim 132, wherein said idling state determining means comprises: means for determining whether or not a speed of said engine is smaller than a predetermined speed; and means for determining whether or not a coolant temperature of said engine is lower than a predetermined temperature, thereby determining that said engine is in an idling state when said engine speed is lower than said predetermined speed and said coolant temperature is lower than said predetermined temperature.
Claim 146
Dependent Claim
88 words
An apparatus as set forth in claim 132, wherein said idling state determining means comprises: means for determining whether or not a speed of said engine is smaller than a predetermined speed; and means for determining whether or not a temperature of said downstream-side air-fuel ratio sensor is lower than a predetermined temperature, thereby determining that said engine is in an idling state when said engine speed is lower than said predetermined speed and said temperature of said downstream-side air-fuel ratio sensor is lower than said predetermined temperature.
Claim 147
Dependent Claim
78 words
An apparatus as set forth in claim 132, wherein said idling state determining means comprises: means for determining whether or not a throttle valve of said engine is comletely closed; and means for determining whether or not an exhaust gas temperature of said engine is lower than a predetermined temperature, thereby determining that said engine is in an idling state when said throttle valve is completely closed and said exhaust gas temperature is lower than said predetermined temperature.
Claim 148
Dependent Claim
76 words
An apparatus as set forth in claim 132, wherein said idling state determining means comprises: means for determining whether or not a throttle valve of said engine is completely closed; and means for determining whether or not a coolant temperature of said engine is lower than a predetermined temperature, thereby determining that said engine is in an idling state when said throttle valve is completely closed and said coolant temperature is lower than said predetermined temperature.
Claim 149
Dependent Claim
86 words
An apparatus as set forth in claim 132, wherein said idling state determining means comprises the steps of: means for determining whether or not a throttle valve of said engine is completely closed; and means for determining whether or not a temperature of said downstream-side air-fuel ratio sensor is lower than a predetermined temperature, thereby determining that said engine is in an idling state when said throttle valve is completely closed and said temperature of said downstream-side air-fuel ratio sensor is lower than said predetermined temperature.
Claim 150
Dependent Claim
36 words
An apparatus as set forth in claim 109, further comprising means for delaying the restart of the calculation of said second air-fuel ratio correction amount for a predetermined duration after said engine leaves said predetermined state.
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USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1991-05-24 | 1991-11-23 | 1992-05-24 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1995-05-24 | 1995-11-23 | 1996-05-24 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1999-05-24 | 1999-11-23 | 2000-05-24 | $7700.00 | Window Closed / Lapsed |