System and method for monitoring exhaust gas hydrocarbon content in internal combustion engines
| Title: | System and method for monitoring exhaust gas hydrocarbon content in internal combustion engines |
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| Patent Number: | 6,098,013 |
| Publication Date: | August 01, 2000 |
| Appl. No: | 09/076,179 |
| Application Filed: | May 11, 1998 |
| Abstract: | A system for monitoring the exhaust gas hydrocarbon content of an internal combustion engine includes at least one sensing device for detecting whether expected combustion conditions occur within the combustion chambers and responsively producing signals indicative of whether the expected combustion conditions occur. An electronic controller is connected to the at least one sensing device for receiving signals therefrom, the electronic controller being operable to determine an estimated exhaust gas hydrocarbon content based upon the signals received from the at least one sensing device. In particular, an engine misfire rate may be determined by the electronic controller and the estimated exhaust gas hydrocarbon content may then be determined as a function of at least the determined engine misfire rate. |
| Inventors: | Mueller, Gary P. (Lafayette, IN) |
| Assignees: | Caterpillar Inc. (Peoria, IL) |
| Claim: | What is claimed is |
| Claim: | 1. A system for monitoring exhaust gas hydrocarbon content of an internal combustion engine including at least one combustion chamber, the system comprising |
| Claim: | at least one sensing device for detecting whether expected combustion conditions occur within the at least one combustion chamber and responsively producing signals indicative of whether the expected combustion conditions occur within the at least one combustion chamber; and |
| Claim: | an electronic controller connected to the at least one sensing device and receiving signals therefrom, said electronic controller being operable to determine an estimated exhaust gas hydrocarbon content based at least in part upon the signals received from the at least one sensing device, to determine an engine misfire rate based upon the signals received from the at least one sensing device, and to determine the estimated exhaust gas hydrocarbon content as a function of at least the determined misfire rate. |
| Claim: | 2. The system, as set forth in claim 1, wherein the electronic controller is operable to compare the estimated exhaust gas hydrocarbon content to a predetermined exhaust gas hydrocarbon content. |
| Claim: | 3. The system, as set forth in claim 2, wherein the electronic controller is operable to effect shut down of the engine if the estimated exhaust gas hydrocarbon content exceeds the predetermined exhaust gas hydrocarbon content. |
| Claim: | 4. The system, as set forth in claim 1, wherein the engine includes a plurality of combustion chambers and the at least one sensing device comprises a distinct sensing device associated with each combustion chamber, the electronic controller connected to each sensing device for receiving signals therefrom. |
| Claim: | 5. A system for monitoring exhaust gas hydrocarbon content of an internal combustion engine having a plurality of combustion chambers, the system comprising |
| Claim: | a combustion probe positioned within each combustion chamber, said combustion probe detecting whether expected combustion conditions occur within a respective combustion chamber and responsively producing signals indicative of whether the expected combustion conditions occur within the respective combustion chamber; and |
| Claim: | an electronic controller connected to each combustion probe and receiving signals therefrom, said electronic controller being operable to determine an estimated exhaust gas hydrocarbon content based at least in part upon the signals received from each combustion probe. |
| Claim: | 6. The system, as set forth in claim 5, wherein the electronic controller comprises an electronic control module and a process loop controller, at least one communication link connecting the process loop controller to the electronic control module. |
| Claim: | 7. A system for monitoring exhaust gas hydrocarbon content of an internal combustion engine including at least one combustion chamber, the system comprising |
| Claim: | an electronic controller connected to the at least one sensing device and receiving signals therefrom, said electronic controller being operable to determine an estimated exhaust gas hydrocarbon content based at least in part upon the signals received from the at least one sensing device, to determine an engine misfire rate based upon the signals received from the at least one sensing device and to determine an air/fuel ratio based upon at least one sensed engine parameter, and wherein the estimated exhaust gas hydrocarbon content is determined as a function of at least the determined engine misfire rate and the determined air/fuel ratio. |
| Claim: | 8. The system, as set forth in claim 7, further comprising |
| Claim: | a speed sensor for sensing a speed of the engine and producing an engine speed indicative signal; and |
| Claim: | wherein the electronic controller is operable to determine a hydrocarbon content normalizing value as a function of at least the engine speed, and wherein the estimated exhaust gas hydrocarbon content is determined as a function of at least the determined engine misfire rate, the determined air/fuel ratio, and the determined hydrocarbon content normalizing value. |
| Claim: | 9. A system for monitoring exhaust gas hydrocarbon content of an internal combustion engine having a plurality of combustion chambers each having a gaseous fuel admission valve associated with an intake port thereof, the system comprising |
| Claim: | at least one sensing device for detecting whether expected combustion conditions occur within the at least one combustion chamber and responsively producing signals indicative of whether the expected combustion conditions occur within the at least one combustion chamber; |
| Claim: | an electronic controller connected to the at least one sensing device and receiving signals therefrom, said electronic controller being operable to determine an estimated exhaust gas hydrocarbon content based at least in part upon the signals received from the at least one sensing device; |
| Claim: | a speed sensor for sensing a speed of the engine and producing an engine speed indicative signal; |
| Claim: | a first pressure sensor for sensing the air pressure within an engine air intake manifold and producing an intake air pressure indicative signal; |
| Claim: | a first temperature sensor for sensing the air temperature within the engine air intake manifold and producing an intake air temperature indicative signal; |
| Claim: | a second pressure sensor for sensing the differential pressure between a gaseous fuel manifold and the air intake manifold, and producing a differential pressure indicative signal; |
| Claim: | a second temperature sensor for sensing the gaseous fuel temperature within the gaseous fuel manifold and producing a gaseous fuel temperature indicative signal; |
| Claim: | each of the speed sensor, the first pressure sensor, the second pressure sensor, the first temperature sensor, and the second temperature sensor connected to the electronic controller for providing its respective signal thereto; |
| Claim: | said electronic controller being operable to determine |
| Claim: | (i) an engine misfire rate as a function of at least the signals received from the at least one sensing device and the engine speed; |
| Claim: | (ii) an air/fuel ratio as a function of the intake air pressure, the intake air temperature, the engine speed, the differential pressure, and the gaseous fuel temperature; |
| Claim: | (iii) a hydrocarbon content normalizing value as a function of the engine speed and an engine load; and |
| Claim: | (iv) the estimated exhaust gas hydrocarbon content as a function of at least the engine misfire rate, the air/fuel ratio, and the hydrocarbon content normalizing value. |
| Claim: | 10. A method of monitoring an exhaust gas hydrocarbon content of an internal combustion engine including a plurality of combustion chambers, the method comprising the steps of |
| Claim: | (a) determining a misfire rate of the engine based upon at least one sensed engine parameter; |
| Claim: | (b) determining an estimated exhaust gas hydrocarbon content as a function of at least the engine misfire rate determined in step (a). |
| Claim: | 11. The method, as set forth in claim 10, including the steps of |
| Claim: | (c) determining an air/fuel ratio being delivered to the combustion chambers; and |
| Claim: | wherein in step (b) the estimated exhaust gas hydrocarbon content is determined as a function of the misfire rate determined in step (a) and the air/fuel ratio determined in step (c). |
| Claim: | 12. The method, as set forth in claim 11, including the step of |
| Claim: | (d) determining a hydrocarbon content normalizing value; and |
| Claim: | wherein in step (b) the estimated exhaust gas hydrocarbon content is determined as a function of at least the misfire rate determined in step (a), the air/fuel ratio determined in step (c), and the hydrocarbon content normalizing value determined in step (d). |
| Claim: | 13. The method, as set forth in claim 12, wherein step (d) includes |
| Claim: | determining a speed of the engine; |
| Claim: | determining a load of the engine; and |
| Claim: | determining the hydrocarbon content normalizing value as a function of at least the determined speed and the determined load. |
| Claim: | 14. The method, as set forth in claim 10, further including the steps of |
| Claim: | comparing the estimated exhaust gas hydrocarbon content determined in step (b) with a predetermined exhaust gas hydrocarbon content; and |
| Claim: | shutting down the engine if the estimated exhaust gas hydrocarbon content determined in step (b) exceeds the predetermined exhaust gas hydrocarbon content. |
| Claim: | 15. The method, as set forth in claim 10, wherein step (a) includes |
| Claim: | detecting whether an expected combustion condition occurs within each of the combustion chambers; |
| Claim: | identifying the absence of an expected combustion condition within a given combustion chamber as a misfire. |
| Claim: | 16. The method, as set forth in claim 10, wherein step (a) involves monitoring the ionization level within each combustion chamber. |
| Current U.S. Class: | 701/112; 731/173; 123/198D |
| Current International Class: | F02D 4122; G01M 1500 |
| Patent References Cited: | 4621603 November 1986 Matekunas 5036669 August 1991 Earleson et al. 5935188 August 1999 Jaye |
| Primary Examiner: | Dolinar, Andrew M. |
| Attorney, Agent or Firm: | Haverstock Garrett & Roberts |
| Accession Number: | edspgr.06098013 |
| Database: | USPTO Patent Grants |
| Language: | English |
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