METHOD FOR DETECTING FUGITIVE FUELING ARISING FROM A PRESSURE-LUBRICATED AIR INLET SYSTEM COMPONENT IN A RECIPROCATING INTERNAL COMBUSTION ENGINE
A method and system for detecting fugitive fueling arising from a pressure-lubricated air inlet system component, such as a turbocharger, within an internal combustion engine includes monitoring lubricating oil pressure within at least one location within the lubrication circuit of the engine and comparing the monitored oil pressure with the failure range contained within a component failure template. If the monitored oil pressure lies within the failure range of the component failure template, remedial action will be taken to mitigate engine damage caused by oil entering engine cylinders from the failed component.
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BACKGROUND OF THE INVENTION1. Field of the Invention
This disclosure relates to the detection and response to unwanted fueling of an internal combustion engine arising from a lubricating oil leak associated with a pressure-lubricated air system component such as a turbocharger.
As used herein, the term “fugitive fueling” means a phenomenon in which an engine receives fuel in excess of that which a fuel controller intends to deliver, either by injectors or by other fuel delivery devices. Fugitive fueling may occur in a variety of situations. For example, if an engine is operated in a hydrocarbon contaminated atmosphere, such as could occur in the event of a spill at a petroleum transfer terminal or a recycling facility, sufficient unwanted or fugitive hydrocarbons may be inducted by the air intake system of an engine to cause overspeed and severe engine damage. A mishap such as a vehicular accident or train wreck may create a fugitive fueling situation, too.
Another type of fugitive fueling may occur due to a leak in an engine lubrication system. Such a leak may occur in a turbocharger or other component connected with the engine's air inlet system. Those skilled in the art will appreciate that engines, particularly diesel engines, are capable of operating quite well on lubricating oil, including lubricating oil aspirated into the engine's cylinders as a result of leaking turbocharger seals or failed turbocharger bearings.
A need exists for a system and method to detect and respond to fugitive fueling resulting from turbocharger or other pressure-lubricated component failure, whether the failure be in the form of leaking seals or worn or broken bearings, or yet other causes, so as to allow an engine to be stopped before damage occurs due to resultant fugitive fueling.
BRIEF DESCRIPTION OF THE INVENTIONAccording to an aspect of the invention, a method for detecting fugitive fueling arising from a pressure-lubricated air inlet system component, such as a turbocharger, within an internal combustion engine having pressure-lubricated main bearings and a pressure-lubricated turbocharger includes monitoring lubricating oil pressure in at least one location within a lubrication circuit of the engine and comparing the monitored oil pressure with a failure range contained within a turbocharger failure template. If the monitored oil pressure lies within the failure range of the turbocharger failure template, remedial action is taken to mitigate engine damage caused by oil entering the engine's cylinders from a failed turbocharger.
According to another aspect of the present invention, the failure template contained within the controller preferably includes a software model for predicting lubricating oil pressure, including an acceptable range of variation exhibited by an engine having a properly operating turbocharger, with the model further including a failure range for the monitored oil pressure which indicates that the turbocharger has failed.
According to another aspect of the present invention, a system for detecting fugitive fueling arising from turbocharger failure within an internal combustion engine includes a pressure sensor for monitoring lubricating oil pressure within a lubrication circuit feeding oil to a turbocharger, and a controller for receiving the output of the pressure sensor and for comparing the sensor output with a turbocharger failure template, with the controller taking at least one step to mitigate engine damage from oil ingestion if the results of the comparison indicate that the turbocharger has failed. The controller may mitigate engine damage in several ways, such as by activating an air supply cutoff device, such as an air shutter in the air inlet system, or by activating a self-load device for the engine or by activating an inert gas supply device for furnishing inert gas to the engine's air inlet system.
It is an advantage of a method and system according to the present invention that fugitive fueling due to turbocharger failure may be detected rapidly, allowing time for an engine to be shut down before further engine damage occurs.
It is another advantage of a method and system according to the present invention that the system may be implemented at least in part with sensors commonly available in turbocharged engines.
Other advantages, as well as features of the present invention will become apparent to readers of this specification.
As shown in
Turbocharger 22 includes not only exhaust turbine 26, but also compressor section 30, which is coupled to exhaust turbine 26 on a common shaft (not shown) having various seals and bearings (not shown). The bearings and seals used in any particular turbocharger are selected by the turbocharger's designer; these details beyond the scope of this invention, it being understood that seals, bearings, and other internal parts of turbochargers are subject to wear and ultimately, to failure. And, failure of turbocharger seals and bearings is frequently accompanied by both the creation of a unique lubrication pressure signature and by aspiration of fugitive oil into the engine's air inlet system. Such oil frequently becomes fugitive fuel.
Engine 10 also includes intercooler 36, which furnishes air to engine air inlet 45. After traveling through engine air inlet 45, air enters intake manifold 40 and then goes into engine 10. If the seals or bearings of turbo 22 fail, oil will pass into intercooler 36 and then into engine air inlet 45. Ultimately, the oil will be drawn into the power cylinders of engine 10.
As shown in
As shown in
At time t2, engine 10 is being decelerated, and at time t3, engine 10 is accelerating in an uncontrolled state, propelled at least in part by fugitive fueling caused by oil leaking from a failed turbocharger. Notice that at time t3, engine speed increases rapidly, and the difference between the observed oil pressure and the predicted oil pressure also increases rapidly.
It may be seen from the foregoing that a window exists from time t1 to time t2 to take remedial action. This of course depends upon the monitoring of lubricating oil pressure depicted in
At block 108, the algorithm within controller 52 asks the question as to whether the oil pressure is within the failure range contained within the turbocharger failure template illustrated as extending between times t1 and t2 of
As noted above, lubricating oil pressure may be measured within a lubrication header downstream from a filter and oil cooler, but upstream from both the turbocharger and the main bearings. Alternatively, the oil pressure may be measured either adjacent the engine's lubricating oil pump or adjacent the turbocharger or, alternatively, within an oil pressure line serving only the turbocharger.
The present method and system may be employed with various pressure-lubricated air inlet system components in addition to the previously described turbocharger. For example, an air-to-oil intercooler leak may result in the ingestion of lubricating oil into an engine's cylinders, producing a response which will be very similar to that caused by a failed turbocharger. And, failures of other types of air system components which utilize or handle lubricating oil under pressure may result in fugitive fueling. Each of these components has a failure template including an oil pressure effect which is unique, and which offers an opportunity to monitor oil pressure as a method for detecting unique component failures. In one embodiment, the component failure template may be configured to indicate failure of a specific pressure-lubricated component when a pressure sensor, such as one of sensors S1-S4, or yet other sensors, indicates that oil pressure is decreasing at a rate in excess of a predetermined threshold.
The foregoing invention has been described in accordance with the relevant legal standards, thus the description is exemplary rather than limiting in nature. Variations and modifications to the disclosed embodiment may become apparent to those skilled in the art and fall within the scope of the invention. Accordingly the scope of legal protection afforded this invention can only be determined by studying the following claims.
Claims
1. A method for detecting fugitive fueling arising from a pressure-lubricated air inlet system component within an internal combustion engine having pressure-lubricated main bearings, with said method comprising:
- monitoring lubricating oil pressure in at least one location within a lubrication circuit of an engine, wherein the monitored oil pressure is indicative of the operational status of a pressure-lubricated component within an intake air system;
- comparing the monitored oil pressure with a failure range contained within a component failure template; and
- if the monitored oil pressure lies within said failure range of said component failure template, taking remedial action to mitigate engine damage caused by oil entering the engine's cylinders from a failed air system component.
2. A method according to claim 1, wherein the lubricating oil pressure is measured within a lubrication header downstream from a filter and oil cooler, but upstream from both the pressure-lubricated component and said main bearings.
3. A method according to claim 1, wherein the lubricating oil pressure is measured within a lubrication header upstream from both the pressure-lubricated component and said main bearings.
4. A method according to claim 1, wherein the lubricating oil pressure is measured proximate the pressure-lubricated component.
5. A method according to claim 1, wherein said component failure template is configured to indicate failure resulting in both an oil leak within the pressure-lubricated component and unintended delivery of lubricating oil to the engine's power cylinders.
6. A method according to claim 5, wherein said component failure template is configured to indicate failure of a turbocharger shaft bearing.
7. A method according to claim 1, wherein said failure template comprises a software model for predicting lubricating oil pressure, including an acceptable range of variation exhibited by an engine having a properly operating turbocharger, with said model further comprising said failure range for said monitored oil pressure indicating that a turbo charger has failed.
8. A method according to claim 1, wherein said monitoring is performed during at least idle operation of the engine.
9. A method according to claim 1, wherein said pressure-lubricated air system component comprises a turbocharger.
10. A system for detecting fugitive fueling arising from turbocharger failure within an internal combustion engine, comprising:
- a pressure sensor for monitoring lubrication oil pressure within a lubrication circuit feeding oil to a turbocharger; and
- a controller for receiving the output of the pressure sensor and for comparing the sensor output with a turbocharger failure template, with said controller taking at least one step to mitigate engine damage from oil ingestion if the results of said comparison indicate that the turbocharger has failed.
11. A system for detecting fugitive fueling according to claim 10, wherein said turbocharger failure template is configured to indicate failure of a turbocharger component causing a discharge of oil from the turbocharger into the engine's cylinders.
12. A system for detecting fugitive fueling according to claim 10, wherein said turbocharger failure template is configured to indicate failure of a turbocharger component causing a discharge of oil into the engine's cylinders.
13. A system according to claim 10, wherein said pressure sensor monitors oil pressure proximate a lubricating oil pump.
14. A system according to claim 10, wherein said pressure sensor monitors lubricating oil pressure within an oil line serving only a turbocharger.
15. A system according to claim 10, wherein said controller mitigates engine damage by activating an air supply cutoff device.
16. A system according to claim 10, wherein said controller mitigates engine damage by activating a self-load device for said engine.
17. A system according to claim 10, wherein said controller mitigates engine damage by activating an inert gas supply device for furnishing inert gas to an air inlet system of the engine.
18. A system according to claim 10, wherein said controller mitigates engine damage by stopping all intended fueling of the engine.
19. A system for detecting fugitive fueling arising from failure of a pressure-lubricated component within an air inlet system of an internal combustion engine, comprising:
- a pressure sensor for monitoring lubrication oil pressure within a lubrication circuit feeding oil to a pressure-lubricated air inlet system component; and
- a controller for receiving the output of the pressure sensor and for comparing the sensor output with a failure template for said pressure-lubricated component, with said controller taking at least one step to mitigate engine damage from oil ingestion if the results of said comparison indicate that said component has failed.
20. A system for detecting fugitive fueling according to claim 19, wherein said component failure template is configured to indicate failure of said component causing a discharge of oil lost from the component into the engine's cylinders.
21. A system for detecting fugitive fueling according to claim 19, wherein said component failure template is configured to indicate failure of said component when said pressure sensor indicates that oil pressure is decreasing at a rate in excess of a predetermined threshold.
Type: Application
Filed: Oct 24, 2007
Publication Date: Apr 30, 2009
Inventors: James R. Mischler (Girard, PA), Luke M. Henry (Erie, PA), Nikita Goel (Erie, PA), Kyle C. Stott (Erie, PA), Kent Jeffries (Fairview, PA), John S. Roth (Erie, PA)
Application Number: 11/877,925
International Classification: F01M 1/18 (20060101);