US5778852A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Functionally monitored fuel injection system
Assignee: Mercedes Benz Group AG
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Filing: 1997-04-25
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Granted: 1998-07-14
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Expires: 2017-04-25
Abstract
Abstract The invention relates to a fuel injection system having an electrically actuatable injection pump which comprises a pre-stroke actuator for setting the start of injection and a flow rate actuator for setting the injection quantity. A control unit for controlling the injection quantity and start of injection emits an actuation signal which starts injection to the flow rate actuator, and an actuation signal for the start of injection to the pre-stroke actuator via an output lead for the actuation signal for the start of injection. According to the invention, the control unit protects the pre-stroke actuator against a short-circuit on the output lead by monitoring the control deviation at the start of injection between the actual value for the start of injection (detected by means of a needle movement sensor) and a desired value for the start of injection, which fixed as a function of the engine operating point. The unit takes protective measures if the control deviation at the start of injection is greater than a prescribable warning threshold value for longer than a prescribable time period.
Inventors
- 👤 Martin Penteker
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-05 11:56
CPC Classifications
F; F02; F02D; F02D41/00; F02D41/22; F02D41/221; F02D41/30; F02D41/38; F02D41/40; F02D41/406; F02D41/408; F02B; F02B3/00; F02B3/06; F02D2041/224; F02D2041/226; F02D2200/00; F02D2200/02; F02D2200/06; F02D2200/063; Y; Y02; Y02T; Y02T10/00; Y02T10/10; Y02T10/40
Claims Analysis
Total Claims: 13
Claim 1
Independent Claim
163 words
Internal combustion engine fuel injection system having an electrically actuatable injection pump with a pre-stroke actuator for setting the start of injection and a control unit for controlling start of injection, which control unit emits an actuation signal for the start of injection to the pre-stroke actuator via an output lead, said fuel injection system further comprising: a needle movement sensor for detecting an actual start of injection based on movement of a needle for controlling fuel flow in said fuel injection system; a comparing device for comparing said actual start of injection with a desired start of injection, to generate a start-of-injection control deviation value; and means in said control unit for protecting the pre-stroke actuator against a short circuit on said output lead, by monitoring said start-of-injection control deviation, detecting when said start-of-injection control deviation exceeds a predeterminable warning threshold value for a time which is longer than a predeterminable time interval, and generating an error detection signal in response thereto.
Claim 2
Dependent Claim
163 words
Internal combustion engine fuel injection system having an electrically actuatable injection pump with a pre-stroke actuator for setting the start of injection and a control unit for controlling start of injection, which control unit emits an actuation signal for the start of injection to the pre-stroke actuator via an output lead, said fuel injection system further comprising: a needle movement sensor for detecting an actual start of injection based on movement of a needle for controlling fuel flow in said fuel injection system; a comparing device for comparing said actual start of injection with a desired start of injection, to generate a start-of-injection control deviation value; and means in said control unit for protecting the pre-stroke actuator against a short circuit on said output lead, by monitoring said start-of-injection control deviation, detecting when said start-of-injection control deviation exceeds a predeterminable warning threshold value for a time which is longer than a predeterminable time interval, and generating an error detection signal in response thereto.
Claim 3
Dependent Claim
42 words
Fuel injection system according to claim 1 further comprising means responsive to said error detection signal for implementing at least one of: emitting a warning signal; and cancelling effectiveness of said actuation signal for the start of injection in said pre-stroke actuator.
Claim 4
Dependent Claim
36 words
Fuel injection system according to claim 1 wherein said desired start of injection is determined by means of a characteristic diagram stored in a desired injection generating unit, as a function of said engine operating point.
Claim 5
Dependent Claim
36 words
Fuel injection system according to claim 2 wherein said desired start of injection is determined by means of a characteristic diagram stored in a desired injection generating unit, as a function of said engine operating point.
Claim 6
Dependent Claim
58 words
Fuel injection system according to claim 1 wherein the control unit emits the warning signal or cancels the effectiveness of the actuation start signal if the actual start of injection is at least approximately 20% ahead of the top dead center of a respective piston stroke of a reciprocating piston engine for longer than the predeterminable time interval.
Claim 7
Dependent Claim
19 words
Fuel injection system according to claim 1 wherein the predeterminable time interval is approximately 10 minutes at a maximum.
Claim 8
Dependent Claim
19 words
Fuel injection system according to claim 2 wherein the predeterminable time interval is approximately 10 minutes at a maximum.
Claim 9
Dependent Claim
157 words
Method of controlling operation of an internal combustion engine fuel injection system having an electrically actuatable injection pump with a pre-stroke actuator for setting the start of injection and a control unit for controlling start of injection, which control unit emits an actuation signal for the start of injection to the pre-stroke actuator via an output lead, said method comprising the steps of: detecting an actual start of fuel injection based on movement of a needle for controlling fuel flow in said fuel injection system; comparing said actual start of injection with a desired start of injection, fixed as a function of an engine operating point of said engine, to generate a start-of-injection control deviation value; monitoring said start-of-injection control deviation to detect an event wherein it exceeds a predeterminable warning threshold value for a time which is longer than a predeterminable time interval; and generating an error detection signal in response to detection of an event.
Claim 10
Dependent Claim
157 words
Method of controlling operation of an internal combustion engine fuel injection system having an electrically actuatable injection pump with a pre-stroke actuator for setting the start of injection and a control unit for controlling start of injection, which control unit emits an actuation signal for the start of injection to the pre-stroke actuator via an output lead, said method comprising the steps of: detecting an actual start of fuel injection based on movement of a needle for controlling fuel flow in said fuel injection system; comparing said actual start of injection with a desired start of injection, fixed as a function of an engine operating point of said engine, to generate a start-of-injection control deviation value; monitoring said start-of-injection control deviation to detect an event wherein it exceeds a predeterminable warning threshold value for a time which is longer than a predeterminable time interval; and generating an error detection signal in response to detection of an event.
Claim 11
Dependent Claim
35 words
Method according to claim 8 further comprising at least one of the additional steps of: emitting a warning signal; and cancelling effectiveness of said actuation signal for the start of injection in said pre-stroke actuator.
Claim 12
Dependent Claim
34 words
Method according to claim 8 wherein said desired start of injection is determined by means of a characteristic diagram stored in a desired injection generating unit, as a function of said engine operating point.
Claim 13
Dependent Claim
34 words
Method according to claim 9 wherein said desired start of injection is determined by means of a characteristic diagram stored in a desired injection generating unit, as a function of said engine operating point.
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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) | 2001-07-13 | 2002-01-12 | 2002-07-14 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 2005-07-13 | 2006-01-12 | 2006-07-14 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2009-07-13 | 2010-01-12 | 2010-07-14 | $7700.00 | Window Closed / Lapsed |