US4628884A
Expired / Lapsed
US
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Method for Lambda control in an internal combustion engine
Assignee: Robert Bosch GmbH
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Filing: 1985-12-24
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Granted: 1986-12-16
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Expires: 2005-12-24
Abstract
Abstract The invention is directed to a method for the formation of an air-fuel mixture for an internal combustion engine, including an oxygen sensor exposed to the exhaust gas and responsive to the oxygen content of the exhaust gas, a signal-processing unit processing the output signals of the oxygen sensor, and a memory store for storing a set of characteristic curves dependent on at least one operating parameter of the internal combustion engine, the characteristic values thereof (F.sub.λ) determining the amount of fuel to be metered. In this method, a time-variable perturbation (ΔF.sub.±) is superposed on the characteristic values (F.sub.λ), the oxygen sensor output signals (U.sub.λ) are evaluated with regard to their change due to the perturbation (ΔF.sub.±), and the characteristic values (F.sub.λ) are suitably corrected to achieve an optimum air-fuel ratio. In this arrangement, the modulation frequency of the characteristic values (F.sub.λ) is to assume as high values as possible while the modulation amplitude is to be as low as possible. This method permits a substantial increase in the limit frequency of the Lambda sensor operation cycles.
Inventors
- 👤 Hans P. Geering
- 👤 Gerhard Heess
- 👤 Helmut Schwarz
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-29 15:51
CPC Classifications
F; F02; F02D; F02D41/00; F02D41/24; F02D41/2406; F02D41/2425; F02D41/2429; F02D41/2451; F02D41/2454; F02D41/2458
Claims Analysis
Total Claims: 23
Claim 1
Independent Claim
198 words
Method for forming the air-fuel mixture for an internal combustion engine having a plurality of cylinders sequentially ejecting pulses of exhaust gas, the engine including an oxygen sensor subjected to said pulses of exhaust gas of the engine and being sensitive to the oxygen content of the extent gas to provide an output signal that is changeable from a high condition to a low condition; a signal processing unit for processing the output signals of the oxygen sensor; and, a storage unit for storing a characteristic field having characteristic field values for determining the quantity of fuel to be metered, the characteristic field being dependent upon at least one operating parameter of the internal combustion engine, the method comprising the steps of: superimposing perturbations upon said characteristic field values (F.sub.λ) that vary with time; evaluating the output signals (U.sub.λ) of the oxygen sensor as to their change with respect to the pertubation quantity; correcting said characteristic field values to obtain an optimum air-fuel mixture; and, causing said output signal to change between said conditions after the smallest possible time interval determined by the time which passes until the next one of said sequential pulses reaches said oxygen sensor.
Claim 2
Dependent Claim
198 words
Method for forming the air-fuel mixture for an internal combustion engine having a plurality of cylinders sequentially ejecting pulses of exhaust gas, the engine including an oxygen sensor subjected to said pulses of exhaust gas of the engine and being sensitive to the oxygen content of the extent gas to provide an output signal that is changeable from a high condition to a low condition; a signal processing unit for processing the output signals of the oxygen sensor; and, a storage unit for storing a characteristic field having characteristic field values for determining the quantity of fuel to be metered, the characteristic field being dependent upon at least one operating parameter of the internal combustion engine, the method comprising the steps of: superimposing perturbations upon said characteristic field values (F.sub.λ) that vary with time; evaluating the output signals (U.sub.λ) of the oxygen sensor as to their change with respect to the pertubation quantity; correcting said characteristic field values to obtain an optimum air-fuel mixture; and, causing said output signal to change between said conditions after the smallest possible time interval determined by the time which passes until the next one of said sequential pulses reaches said oxygen sensor.
Claim 3
Dependent Claim
76 words
The method of claim 1, wherein said perturbations are bipolar and continuously change with time, and the method includes the further steps of: superimposing said perturbations upon said characteristic values according to a predetermined pulse pattern, the individual pulses corresponding to respective ones of said individual cylinders; and, analyzing the deviations of the pulse pattern resulting on the oxygen sensor from the expected pulse pattern which has a causal functional relationship with the perturbation pulse pattern.
Claim 4
Dependent Claim
22 words
The method of claim 2, wherein the predetermined pulse pattern is freely assembled in dependence upon the operational condition of the engine.
Claim 5
Dependent Claim
44 words
The method of claim 2, wherein said predetermined pulse pattern of said bipolar perturbations is continuously changed with time so as to cause a cylinder perturbated in the rich direction to cyclically alternate with cylinders perturbated in the lean direction after a predeterminable time.
Claim 6
Dependent Claim
32 words
The method of claim 4, wherein the predetermined pulse pattern is changed after said predeterminable time, and wherein said predeterminable time is changeable in dependence upon the operational condition of the engine.
Claim 7
Dependent Claim
30 words
The method of claim 1, comprising: adding or subtracting a perturbation quantity (ΔF.sub.±) to or from said characteristic field values to realize said perturbation of said characteristic field values (F.sub.λ).
Claim 8
Dependent Claim
37 words
The method of claim 6, comprising the step of superposing said perturbation quantity (ΔF.sub.±) on just the characteristic field value (F.sub.λ) selected in dependence upon at least one of the operating parameters of the internal combustion engine.
Claim 9
Dependent Claim
27 words
The method of claim 7, the time variation of said perturbation quantity (ΔF.sub.±) occurring in dependence upon at least one operating parameter of the internal combustion engine.
Claim 10
Dependent Claim
17 words
The method of claim 7, the time variation of said perturbation quantity (ΔF.sub.±) occurring with constant frequency.
Claim 11
Dependent Claim
37 words
The method of claim 9, comprising the step of comparing the output signal (U.sub.λ) of the oxygen sensor with perturbation quantity while taking account of the time delay (T+τ) between said output signal and said perturbation quantity.
Claim 12
Dependent Claim
40 words
The method of claim 10, comprising the step of cancelling said time delay between the output signals (U.sub.λ) of the oxygen sensor and the perturbation by means of a storage of the perturbation quantity (ΔF.sub.±) in an intermediate storage unit.
Claim 13
Dependent Claim
26 words
The method of claim 11, the storage time of said intermediate storage unit being adjustable in dependence upon the operating parameters of the internal combustion engine.
Claim 14
Dependent Claim
40 words
The method of claim 11, comprising the step of realizing the storage time of said intermediate storage unit in dependence upon the result of cross-correlation analysis of the perturbation quantity (ΔF.sub.±) and the output signal (U.sub.λ) of said oxygen sensor.
Claim 15
Dependent Claim
40 words
The method of claim 13, comprising the step of changing the amplitude of the perturbation quantity (ΔF.sub.±) in dependence upon the result of said comparison of the perturbation quantity with the output signal of the oxygen sensor output quantity (U.sub.λ).
Claim 16
Dependent Claim
46 words
The method of claim 14, comprising the step of correcting said characteristic field values to a value of the air-fuel ratio for which the toxic materials contained in the exhaust gas are reduced to a minimal value by means of a catalytic after-treatment or the like.
Claim 17
Dependent Claim
20 words
The method of claim 15, said characteristic field values being corrected to an air-fuel ratio in the neighborhood of λ=1.
Claim 18
Dependent Claim
61 words
The method of claim 16, comprising the step of depositing said characteristic field values in the storage unit for said set of characteristic curves in dependence upon the rotational speed (n) of the engine and at least one of: the quantity of air inducted by the engine and the pressure (P L ) in the air intake tube of the engine.
Claim 19
Dependent Claim
50 words
The method of claim 17, wherein the engine has a plurality of separately controlled individual injection valves, the method comprising the step of superposing a perturbation (ΔF.sub.±) on the characteristic field value (F.sub.λ) determining the quantity of fuel for at most once per metering of fuel for each individual cylinder.
Claim 20
Dependent Claim
49 words
The method of claim 17, comprising the step of reducing the modulation frequency of the characteristic field values (F.sub.λ) determining the metering of fuel for the case wherein said plurality of injection valves are controlled in common as compared to the case wherein said injection valves are controlled separately.
Claim 21
Dependent Claim
22 words
The method of claim 18, comprising the step of correcting the characteristic field values specifically for each cylinder and storing the same.
Claim 22
Dependent Claim
45 words
The method of claim 18, comprising the step of determining the characteristic field values for one cylinder and comparing the latter values with the mean value from the characteristic field values of other cylinders and storing cylinder correction values for said one cylinder as required.
Claim 23
Dependent Claim
25 words
The method of claim 21, comprising the step of carrying out the individual cylinder adaptation of the characteristic field values (F.sub.λ) in definite time intervals.
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| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
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| 3.5 Years (Year 4) | 1989-12-15 | 1990-06-16 | 1990-12-16 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1993-12-15 | 1994-06-16 | 1994-12-16 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1997-12-15 | 1998-06-16 | 1998-12-16 | $7700.00 | Window Closed / Lapsed |