CA2255462A1 - Method for nox reduction of internal combustion - Google Patents
Method for nox reduction of internal combustion Download PDFInfo
- Publication number
- CA2255462A1 CA2255462A1 CA002255462A CA2255462A CA2255462A1 CA 2255462 A1 CA2255462 A1 CA 2255462A1 CA 002255462 A CA002255462 A CA 002255462A CA 2255462 A CA2255462 A CA 2255462A CA 2255462 A1 CA2255462 A1 CA 2255462A1
- Authority
- CA
- Canada
- Prior art keywords
- temperature
- average mass
- lambda
- internal combustion
- exhaust gas
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Abandoned
Links
Classifications
-
- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F02—COMBUSTION ENGINES; HOT-GAS OR COMBUSTION-PRODUCT ENGINE PLANTS
- F02D—CONTROLLING COMBUSTION ENGINES
- F02D41/00—Electrical control of supply of combustible mixture or its constituents
- F02D41/02—Circuit arrangements for generating control signals
- F02D41/14—Introducing closed-loop corrections
- F02D41/1438—Introducing closed-loop corrections using means for determining characteristics of the combustion gases; Sensors therefor
- F02D41/1473—Introducing closed-loop corrections using means for determining characteristics of the combustion gases; Sensors therefor characterised by the regulation method
- F02D41/1475—Regulating the air fuel ratio at a value other than stoichiometry
-
- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F02—COMBUSTION ENGINES; HOT-GAS OR COMBUSTION-PRODUCT ENGINE PLANTS
- F02D—CONTROLLING COMBUSTION ENGINES
- F02D41/00—Electrical control of supply of combustible mixture or its constituents
- F02D41/02—Circuit arrangements for generating control signals
- F02D41/14—Introducing closed-loop corrections
- F02D41/1497—With detection of the mechanical response of the engine
- F02D41/1498—With detection of the mechanical response of the engine measuring engine roughness
-
- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F02—COMBUSTION ENGINES; HOT-GAS OR COMBUSTION-PRODUCT ENGINE PLANTS
- F02D—CONTROLLING COMBUSTION ENGINES
- F02D2200/00—Input parameters for engine control
- F02D2200/02—Input parameters for engine control the parameters being related to the engine
- F02D2200/10—Parameters related to the engine output, e.g. engine torque or engine speed
- F02D2200/1015—Engines misfires
-
- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F02—COMBUSTION ENGINES; HOT-GAS OR COMBUSTION-PRODUCT ENGINE PLANTS
- F02D—CONTROLLING COMBUSTION ENGINES
- F02D2250/00—Engine control related to specific problems or objectives
- F02D2250/36—Control for minimising NOx emissions
-
- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F02—COMBUSTION ENGINES; HOT-GAS OR COMBUSTION-PRODUCT ENGINE PLANTS
- F02D—CONTROLLING COMBUSTION ENGINES
- F02D41/00—Electrical control of supply of combustible mixture or its constituents
- F02D41/02—Circuit arrangements for generating control signals
- F02D41/14—Introducing closed-loop corrections
- F02D41/1438—Introducing closed-loop corrections using means for determining characteristics of the combustion gases; Sensors therefor
- F02D41/1444—Introducing closed-loop corrections using means for determining characteristics of the combustion gases; Sensors therefor characterised by the characteristics of the combustion gases
- F02D41/1446—Introducing closed-loop corrections using means for determining characteristics of the combustion gases; Sensors therefor characterised by the characteristics of the combustion gases the characteristics being exhaust temperatures
Landscapes
- Engineering & Computer Science (AREA)
- Chemical & Material Sciences (AREA)
- Combustion & Propulsion (AREA)
- Mechanical Engineering (AREA)
- General Engineering & Computer Science (AREA)
- Combined Controls Of Internal Combustion Engines (AREA)
- Electrical Control Of Air Or Fuel Supplied To Internal-Combustion Engine (AREA)
- Exhaust Gas After Treatment (AREA)
- Combustion Methods Of Internal-Combustion Engines (AREA)
Abstract
In a method for reducing NO x in the exhaust gas of an internal combustion engine that is always operated at a lean fuel/air ratio of .lambda. > 1 and has a motor control device for controlling .lambda., the .lambda.
value is slidingly controlled as a function of an average mass temperature in the combustion chamber of the internal combustion engine, wherein for a low average mass temperature .lambda. is decreased and for a high average mass temperature A is increased such that the internal combustion engine is operated in any operational state close to the misfiring limit.
value is slidingly controlled as a function of an average mass temperature in the combustion chamber of the internal combustion engine, wherein for a low average mass temperature .lambda. is decreased and for a high average mass temperature A is increased such that the internal combustion engine is operated in any operational state close to the misfiring limit.
Description
CA 022~462 1998-12-11 Background of the Invention The present invention relates to a method for reducing NOX
of internal combustion engines in which the internal combustion engine is always operated at an air ratio of A > 1 in a lean mode and the A value of the fuel/air mixture is controlled by an engine control device.
For the purpose of reducing the NOX values in the exhaust gas of internal combustion engines it is known to operate them with a lean mixture at A > 1. Because of the high average mass temperature in the combustion chamber during stationary operation, high A values must be selected in order to achieve low NOX
emission.
Difficulties arise during non-stationary operation, forexample, during acceleration from low engine rpm (revolutions per minute), when the average mass temperature in the combustion chamber is lower than during stationary operation and the misfire limit moves toward lower A values.
It is therefore an object of the present invention to control the A value of the internal combustion engine such that, for the purpose of NOX reduction, the engine is operated close to the misfire limit.
Summary of the Invention Inventively, this object is solved in that the A value is slidingly CA 022~462 1998-12-11 controlled as a function of the average mass temperature in the combustion chamber of the internal combustion engine such that for low average mass temperature the A value is decreased and for high average mass temperature the A value is increased so that the internal combustion engine, under any operating condition, is operated close to the misfire limit.
Since the control of A is based on the average mass temperature, the fuel/air mixture can be made so lean or so rich that the misfire limit is almost reached but not surpassed. The NOX
reduction process is thus expanded to its physically possible limit.
Description of Preferred Embodiments An advantageous possibility for determining the average mass temperature is as follows. The exhaust gas temperature is measured by a temperature sensor and the measured exhaust gas temperature, which is a measure of the average mass temperature, is employed in the controlling step. The exhaust gas temperature reflects the average mass temperature so that the exhaust gas temperature can be used as a substitute for the average mass temperature. The exhaust gas temperature can be easily determined by a temperature sensor and can be used in the engine control device for controlling the A value.
Another advantageous embodiment is as follows. With the CA 022~462 1998-12-11 aid of the engine control device the exhaust gas temperature is calculated based on one or more operational parameters of the internal combustion engine. The operational parameters include load, engine rpm, coolant temperature, and atmospheric temperature etc. The calculated exhaust gas temperature, that is a function of the average mass temperature, is then used in the step of controlling. Since the exhaust gas temperature is dependent on the average mass temperature, the calculated exhaust gas temperature can be used as a substitute control signal by the engine control device for the purpose of controlling the A value.
. According to another embodiment of the invention, the cylinder pressure curve of the internal combustion engine is measured and based on the measured curve the average mass temperature is calculated. A pressure sensor is used to measure the pressure curve of the cylinder and then the average mass temperature is calculated therefrom and employed for controlling the A value.
The invention is based on the recognition that the A value is not a fixed value but that the critical limit for A in the dynamic range of the engine has no set value but is a sliding limit that depends on the average mass temperature in the combustion chamber.
The problem is that the currently known temperature sensors CA 022~462 1998-12-11 are too slow to make direct use of the average mass temperature for a sliding control of the maximum A value possible according to physical principles. According to the methods of the prior art, it is necessary to lower A in the dynamic range of operation in order to prevent misfiring. The lowering of the A value, however, results in increased NOX concentrations in the exhaust gas.
The inventive method suggests to treat the A value as a function of the average mass temperature of the fuel/air mixture to be compressed within the combustion chamber. Since this average mass temperature cannot be determined directly, it is inventively suggested to determine the average mass temperature based on measurable parameters, for example, by measuring the exhaust gas temperature with the aid of a temperature sensor and to then either calculate the average mass temperature with the aid of the engine control device as a function of the measured exhaust gas temperature and use the calculated result for controlling the maximum allowable A value or to use the exhaust gas temperature as a substitute for the average mass temperature for adjusting the A value.
A further option, instead of measuring the exhaust gas temperature, suggests to calculate with the aid of the engine control device the exhaust gas temperature based on parameters such as CA 022~462 1998-12-11 load, engine rpm, coolant temperature and atmospheric temperature, and to determine based thereon the average mass temperature to thereby control the A value.
A further option for a sliding control of the A value is to measure the cylinder pressure curve by a pressure sensor. With the aid of a combustion analysis the average mass temperature can be calculated and the A value can be controlled.
The inventive method allows control of the A value in the dynamic operational ranges of the combustion engine up to the misfire limit of the engine without ever surpassing the misfire limit.
The maximum exploitation of the theoretically possible spectrum of the A value ensures a minimization of the pollutant component in the exhaust gas, especially of NOx.
The specification incorporates by reference the disclosure of German priority document 197 55 299.4 of December 12, 1997.
The present invention is, of course, in no way restricted to the specific disclosure of the specification and drawings, but also encompasses any modifications within the scope of the appended claims.
of internal combustion engines in which the internal combustion engine is always operated at an air ratio of A > 1 in a lean mode and the A value of the fuel/air mixture is controlled by an engine control device.
For the purpose of reducing the NOX values in the exhaust gas of internal combustion engines it is known to operate them with a lean mixture at A > 1. Because of the high average mass temperature in the combustion chamber during stationary operation, high A values must be selected in order to achieve low NOX
emission.
Difficulties arise during non-stationary operation, forexample, during acceleration from low engine rpm (revolutions per minute), when the average mass temperature in the combustion chamber is lower than during stationary operation and the misfire limit moves toward lower A values.
It is therefore an object of the present invention to control the A value of the internal combustion engine such that, for the purpose of NOX reduction, the engine is operated close to the misfire limit.
Summary of the Invention Inventively, this object is solved in that the A value is slidingly CA 022~462 1998-12-11 controlled as a function of the average mass temperature in the combustion chamber of the internal combustion engine such that for low average mass temperature the A value is decreased and for high average mass temperature the A value is increased so that the internal combustion engine, under any operating condition, is operated close to the misfire limit.
Since the control of A is based on the average mass temperature, the fuel/air mixture can be made so lean or so rich that the misfire limit is almost reached but not surpassed. The NOX
reduction process is thus expanded to its physically possible limit.
Description of Preferred Embodiments An advantageous possibility for determining the average mass temperature is as follows. The exhaust gas temperature is measured by a temperature sensor and the measured exhaust gas temperature, which is a measure of the average mass temperature, is employed in the controlling step. The exhaust gas temperature reflects the average mass temperature so that the exhaust gas temperature can be used as a substitute for the average mass temperature. The exhaust gas temperature can be easily determined by a temperature sensor and can be used in the engine control device for controlling the A value.
Another advantageous embodiment is as follows. With the CA 022~462 1998-12-11 aid of the engine control device the exhaust gas temperature is calculated based on one or more operational parameters of the internal combustion engine. The operational parameters include load, engine rpm, coolant temperature, and atmospheric temperature etc. The calculated exhaust gas temperature, that is a function of the average mass temperature, is then used in the step of controlling. Since the exhaust gas temperature is dependent on the average mass temperature, the calculated exhaust gas temperature can be used as a substitute control signal by the engine control device for the purpose of controlling the A value.
. According to another embodiment of the invention, the cylinder pressure curve of the internal combustion engine is measured and based on the measured curve the average mass temperature is calculated. A pressure sensor is used to measure the pressure curve of the cylinder and then the average mass temperature is calculated therefrom and employed for controlling the A value.
The invention is based on the recognition that the A value is not a fixed value but that the critical limit for A in the dynamic range of the engine has no set value but is a sliding limit that depends on the average mass temperature in the combustion chamber.
The problem is that the currently known temperature sensors CA 022~462 1998-12-11 are too slow to make direct use of the average mass temperature for a sliding control of the maximum A value possible according to physical principles. According to the methods of the prior art, it is necessary to lower A in the dynamic range of operation in order to prevent misfiring. The lowering of the A value, however, results in increased NOX concentrations in the exhaust gas.
The inventive method suggests to treat the A value as a function of the average mass temperature of the fuel/air mixture to be compressed within the combustion chamber. Since this average mass temperature cannot be determined directly, it is inventively suggested to determine the average mass temperature based on measurable parameters, for example, by measuring the exhaust gas temperature with the aid of a temperature sensor and to then either calculate the average mass temperature with the aid of the engine control device as a function of the measured exhaust gas temperature and use the calculated result for controlling the maximum allowable A value or to use the exhaust gas temperature as a substitute for the average mass temperature for adjusting the A value.
A further option, instead of measuring the exhaust gas temperature, suggests to calculate with the aid of the engine control device the exhaust gas temperature based on parameters such as CA 022~462 1998-12-11 load, engine rpm, coolant temperature and atmospheric temperature, and to determine based thereon the average mass temperature to thereby control the A value.
A further option for a sliding control of the A value is to measure the cylinder pressure curve by a pressure sensor. With the aid of a combustion analysis the average mass temperature can be calculated and the A value can be controlled.
The inventive method allows control of the A value in the dynamic operational ranges of the combustion engine up to the misfire limit of the engine without ever surpassing the misfire limit.
The maximum exploitation of the theoretically possible spectrum of the A value ensures a minimization of the pollutant component in the exhaust gas, especially of NOx.
The specification incorporates by reference the disclosure of German priority document 197 55 299.4 of December 12, 1997.
The present invention is, of course, in no way restricted to the specific disclosure of the specification and drawings, but also encompasses any modifications within the scope of the appended claims.
Claims (4)
1. A method for reducing NO x in the exhaust gas of an internal combustion engine that is always operated at a lean fuel/air ratio of .lambda. > 1, wherein .lambda. is controlled by an engine control device, said method comprising the step of:
slidingly controlling .lambda. as a function of an average mass temperature in the combustion chamber of the internal combustion engine, wherein for a low average mass temperature .lambda. is decreased and for a high average mass temperature .lambda. is increased such that the internal combustion engine is operated in any operational state close to the misfiring limit.
slidingly controlling .lambda. as a function of an average mass temperature in the combustion chamber of the internal combustion engine, wherein for a low average mass temperature .lambda. is decreased and for a high average mass temperature .lambda. is increased such that the internal combustion engine is operated in any operational state close to the misfiring limit.
2. A method according to claim 1, further comprising the step of measuring the exhaust gas temperature by a temperature sensor and employing the exhaust gas temperature, which is a measure of the average mass temperature, in the step of controlling .lambda..
3. A method according to claim 1, further comprising the step of calculating with the aid of the engine control device the exhaust gas temperature based on one or more operational parameters of the internal combustion engine, said operational parameters selected from the group consisting of load, engine rpm, coolant temperature, and atmospheric temperature, and employing the exhaust gas temperature, which is a measure of the average mass temperature, in the step of controlling .lambda..
4. A method according to claim 1, further comprising the step of measuring a cylinder pressure curve of the internal combustion engine and calculating the average mass temperature based on the cylinder pressure curve.
Applications Claiming Priority (2)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| DE19755299.4 | 1997-12-12 | ||
| DE19755299A DE19755299A1 (en) | 1997-12-12 | 1997-12-12 | Process for NO¶x¶ reduction in mixture-compressing internal combustion engines |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CA2255462A1 true CA2255462A1 (en) | 1999-06-12 |
Family
ID=7851713
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA002255462A Abandoned CA2255462A1 (en) | 1997-12-12 | 1998-12-11 | Method for nox reduction of internal combustion |
Country Status (4)
| Country | Link |
|---|---|
| EP (1) | EP0922846B1 (en) |
| AU (1) | AU9705398A (en) |
| CA (1) | CA2255462A1 (en) |
| DE (2) | DE19755299A1 (en) |
Families Citing this family (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| DE19852240A1 (en) | 1998-11-12 | 2000-05-18 | Volkswagen Ag | Monitoring method for NOx storage catalytic converters and exhaust gas purification device for carrying out this method |
| DE10307367A1 (en) * | 2003-02-21 | 2004-09-09 | B + V Industrietechnik Gmbh | Regulating gas-powered engines involves measuring combustion pressure in each cylinder, controlling fuel feed depending on pressure evaluation carried out immediately after pressure value measurement |
| FI124007B (en) * | 2008-12-16 | 2014-01-31 | Waertsilae Finland Oy | Method and system for controlling combustion engine emissions |
Family Cites Families (10)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| DE3204842A1 (en) * | 1982-02-11 | 1983-08-18 | Volkswagenwerk Ag, 3180 Wolfsburg | Device for controlling a spark-ignition internal-combustion engine |
| DE3410930A1 (en) * | 1984-03-24 | 1985-10-03 | Motoren-Werke Mannheim AG vorm. Benz Abt. stationärer Motorenbau, 6800 Mannheim | Device for controlling the combustion air ratio in Otto gas engines with exhaust gas catalysts |
| DE3500594C2 (en) * | 1985-01-10 | 1995-08-17 | Bosch Gmbh Robert | Metering system for an internal combustion engine to influence the operating mixture |
| DE3673175D1 (en) * | 1985-01-10 | 1990-09-13 | Atlas Fahrzeugtechnik Gmbh | MIXTURE CONTROL DEVICE FOR AN INTERNAL COMBUSTION ENGINE. |
| JPS6388241A (en) * | 1986-09-30 | 1988-04-19 | Mitsubishi Electric Corp | Air-fuel ratio control device for internal combustion engine |
| US4887574A (en) * | 1987-04-21 | 1989-12-19 | Hitachi, Ltd. | Control apparatus for internal combustion engines |
| JPH03225045A (en) * | 1990-01-31 | 1991-10-04 | Toyota Motor Corp | Air-fuel ratio control device for internal combustion engine |
| DE4033026C2 (en) * | 1990-10-18 | 1997-09-04 | Bayerische Motoren Werke Ag | Method for avoiding thermally critical states of an exhaust gas aftertreatment device for an internal combustion engine |
| JPH04234542A (en) * | 1990-12-28 | 1992-08-24 | Honda Motor Co Ltd | Air-fuel ratio control method for internal combustion engine |
| DE4420946B4 (en) * | 1994-06-16 | 2007-09-20 | Robert Bosch Gmbh | Control system for fuel metering in an internal combustion engine |
-
1997
- 1997-12-12 DE DE19755299A patent/DE19755299A1/en not_active Withdrawn
-
1998
- 1998-11-04 DE DE59811462T patent/DE59811462D1/en not_active Expired - Lifetime
- 1998-11-04 EP EP98120906A patent/EP0922846B1/en not_active Expired - Lifetime
- 1998-12-10 AU AU97053/98A patent/AU9705398A/en not_active Abandoned
- 1998-12-11 CA CA002255462A patent/CA2255462A1/en not_active Abandoned
Also Published As
| Publication number | Publication date |
|---|---|
| AU9705398A (en) | 1999-07-01 |
| EP0922846A3 (en) | 2002-05-15 |
| DE59811462D1 (en) | 2004-07-01 |
| EP0922846A2 (en) | 1999-06-16 |
| DE19755299A1 (en) | 1999-06-17 |
| EP0922846B1 (en) | 2004-05-26 |
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Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| FZDE | Dead |