WO2015189012A1 - Exhaust gas recirculation testing method - Google Patents
Exhaust gas recirculation testing method Download PDFInfo
- Publication number
- WO2015189012A1 WO2015189012A1 PCT/EP2015/061052 EP2015061052W WO2015189012A1 WO 2015189012 A1 WO2015189012 A1 WO 2015189012A1 EP 2015061052 W EP2015061052 W EP 2015061052W WO 2015189012 A1 WO2015189012 A1 WO 2015189012A1
- Authority
- WO
- WIPO (PCT)
- Prior art keywords
- gas recirculation
- exhaust
- exhaust gas
- engine
- exhaust brake
- Prior art date
Links
Classifications
-
- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F02—COMBUSTION ENGINES; HOT-GAS OR COMBUSTION-PRODUCT ENGINE PLANTS
- F02D—CONTROLLING COMBUSTION ENGINES
- F02D9/00—Controlling engines by throttling air or fuel-and-air induction conduits or exhaust conduits
- F02D9/04—Controlling engines by throttling air or fuel-and-air induction conduits or exhaust conduits concerning exhaust conduits
- F02D9/06—Exhaust brakes
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- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F02—COMBUSTION ENGINES; HOT-GAS OR COMBUSTION-PRODUCT ENGINE PLANTS
- F02D—CONTROLLING COMBUSTION ENGINES
- F02D21/00—Controlling engines characterised by their being supplied with non-airborne oxygen or other non-fuel gas
- F02D21/06—Controlling engines characterised by their being supplied with non-airborne oxygen or other non-fuel gas peculiar to engines having other non-fuel gas added to combustion air
- F02D21/08—Controlling engines characterised by their being supplied with non-airborne oxygen or other non-fuel gas peculiar to engines having other non-fuel gas added to combustion air the other gas being the exhaust gas of engine
-
- 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
- F02D41/0025—Controlling engines characterised by use of non-liquid fuels, pluralities of fuels, or non-fuel substances added to the combustible mixtures
- F02D41/0047—Controlling exhaust gas recirculation [EGR]
- F02D41/005—Controlling exhaust gas recirculation [EGR] according to engine operating conditions
- F02D41/0055—Special engine operating conditions, e.g. for regeneration of exhaust gas treatment apparatus
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- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F02—COMBUSTION ENGINES; HOT-GAS OR COMBUSTION-PRODUCT ENGINE PLANTS
- F02M—SUPPLYING COMBUSTION ENGINES IN GENERAL WITH COMBUSTIBLE MIXTURES OR CONSTITUENTS THEREOF
- F02M26/00—Engine-pertinent apparatus for adding exhaust gases to combustion-air, main fuel or fuel-air mixture, e.g. by exhaust gas recirculation [EGR] systems
- F02M26/02—EGR systems specially adapted for supercharged engines
- F02M26/04—EGR systems specially adapted for supercharged engines with a single turbocharger
- F02M26/05—High pressure loops, i.e. wherein recirculated exhaust gas is taken out from the exhaust system upstream of the turbine and reintroduced into the intake system downstream of the compressor
-
- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F02—COMBUSTION ENGINES; HOT-GAS OR COMBUSTION-PRODUCT ENGINE PLANTS
- F02M—SUPPLYING COMBUSTION ENGINES IN GENERAL WITH COMBUSTIBLE MIXTURES OR CONSTITUENTS THEREOF
- F02M26/00—Engine-pertinent apparatus for adding exhaust gases to combustion-air, main fuel or fuel-air mixture, e.g. by exhaust gas recirculation [EGR] systems
- F02M26/49—Detecting, diagnosing or indicating an abnormal function of the EGR system
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- Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
- Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
- Y02T—CLIMATE CHANGE MITIGATION TECHNOLOGIES RELATED TO TRANSPORTATION
- Y02T10/00—Road transport of goods or passengers
- Y02T10/10—Internal combustion engine [ICE] based vehicles
- Y02T10/40—Engine management systems
Definitions
- This invention relates to exhaust gas recirculation systems, and in particular to determining the functionality thereof.
- EGR exhaust gas recirculation
- NOx nitrogen oxide
- An error which may occur may be that the EGR valve may become blocked.
- the methods involve monitoring the mass air flow (MAF) or boost pressure by way of sensors in response to perturbation of the EGR valve position.
- MAF mass air flow
- boost pressure boost pressure
- an engine ECU schedules such checks when certain conditions (operating points) are achieved.
- a problem is that such a check cannot be carried out on demand, but is dependent on these required operating conditions to be present.
- a method of monitoring the functionality of an exhaust gas recirculation system/valve in a vehicle engine system which includes an exhaust brake comprising: applying said exhaust brake; monitoring the functionality of the exhaust gas recirculation system whilst the exhaust brake is applied .
- the method preferably is implemented when the vehicle is in a load off condition or is in neutral gear.
- the method can be performed in gear, and during which fuelling to the engine can be adjusted to compensate for the reduction in torque as a result of applying the exhaust brake.
- Figure 1 shows a schematic diagram of an engine system to which methodology of examples can be applied.
- Figure 1 shows an engine system 1 to which examples of the invention may be applied.
- the figure shows schematically the flow components of an engine system 1 which employs EGR. Specifically it shows the layout of the components of a typical turbo-charged diesel engine, with the strategy for the invention located in an engine control unit.
- Air flow into the system is filtered by air filter 2 and may pass through a mass air flow (MAF) sensor 3 if fitted.
- a compressor 4 of a turbocharged system is a mass air flow (MAF) sensor 3 if fitted.
- a boost (MAP) pressure sensor 8 senses the pressure at the engine intake. Exhaust gases exiting the engine power the turbo 9 and an exhaust brake unit 10 before being passed through exhaust after- treatment units 1 1.
- an EGR valve 12 and EGR cooler 13 are provided as shown.
- An ECU control various engine systems including the exhaust brake and EGR valve, and may also monitor MAP and MAF.
- An exhaust brake is a means of slowing an engine by closing off the exhaust path from the engine, causing the exhaust gases to be compressed in the exhaust manifold, and in the cylinder. Since the exhaust is being compressed, and there is no fuel being applied, the engine works backwards, slowing down the vehicle. The amount of negative torque generated is usually directly proportional to the back pressure of the engine.
- Known applications of the exhaust brake on commercial vehicles are to slow the vehicle when in gear on tip-out, and to warm the engine faster.
- An Engine Control Unit is shown which in aspects of the invention provides the necessary control of the methodologies.
- the exhaust brake which is usually fitted to most trucks, is applied in under certain conditions, where there is no detrimental effect - such as power off conditions, braking conditions (for example when said air brake is usually used) or when the vehicle is in neutral gear and/or any condition when the air brake is conventionally used.
- Application of the exhaust brake increases the engine back pressure, thus creating conditions conducive for EGR flow and thereby allowing known methods for evaluating the EGR flow to be executed, when they might otherwise not have been able to run.
- an EGR flow check may be forced by applying the exhaust brake even when, for example, the vehicle is in gear.
- Such methods may be implemented such that (e.g. the torque controller/ECU) the fuelling is adjusted appropriately (by providing more fuel) to compensate for the braking action. So in this manner the method a check can be forced to occur while the vehicle was in gear. This would be a small fuel penalty, but only a very short period is needed (e.g. 1 or 2 seconds) to perform the check.
- the optional functional block of fuel adjustment is shown in the figure as 15.
- the invention allows the range of operating conditions where the EGR flow check can be carried out, to be expanded.
- the invention is applicable to engine systems without turbochargers.
Abstract
A method of monitoring the functionality of an exhaust gas recirculation system/valve in a vehicle engine system which includes an exhaust brake comprising: applying said exhaust brake; monitoring the functionality of the exhaust gas recirculation system whilst the exhaust brake is applied.
Description
Exhaust Gas Recirculation Testing Method
Field of the Invention
This invention relates to exhaust gas recirculation systems, and in particular to determining the functionality thereof.
Background of the Invention
In internal combustion engines, exhaust gas recirculation (EGR) is a technique used to reduce nitrogen oxide (NOx) emissions in both petrol and diesel engines. In EGR systems a portion of an engine's exhaust gas is recycled back to the engine cylinders. Because NOx forms primarily when a mixture of nitrogen and oxygen is subjected to high temperature, the lower combustion chamber temperatures caused by EGR reduces the amount of NOx the combustion generates
An error which may occur may be that the EGR valve may become blocked.
There are two known methods for checking the functionality of the high pressure recycled exhaust flow. The methods involve monitoring the mass air flow (MAF) or boost pressure by way of sensors in response to perturbation of the EGR valve position. On commercial vehicles, which are not usually fitted with an intake throttles, such a check is only possible during a limited set of speed and load operating points, when there is sufficient differential pressure across the EGR valve, for EGR to be expected to flow. Typically an engine ECU schedules such checks when certain conditions (operating points) are achieved. A problem is that
such a check cannot be carried out on demand, but is dependent on these required operating conditions to be present.
It is also difficult to flow EGR when the turbine is operating very efficiently, providing lots of boost, e.g. at high load.
It is an object of the invention to provide a method whereby the EGR check can be performed over a greater time window.
Summary of the Invention
In one aspect of the invention is provided a method of monitoring the functionality of an exhaust gas recirculation system/valve in a vehicle engine system which includes an exhaust brake comprising: applying said exhaust brake; monitoring the functionality of the exhaust gas recirculation system whilst the exhaust brake is applied .
The method preferably is implemented when the vehicle is in a load off condition or is in neutral gear. The method can be performed in gear, and during which fuelling to the engine can be adjusted to compensate for the reduction in torque as a result of applying the exhaust brake.
Brief description of the figures
The invention will now be described by way of example and with reference to the following figures of which:
Figure 1 shows a schematic diagram of an engine system to which methodology of examples can be applied.
Detailed Description
Figure 1 shows an engine system 1 to which examples of the invention may be applied. The figure shows schematically the flow components of an engine system 1 which employs EGR. Specifically it shows the layout of the components of a typical turbo-charged diesel engine, with the strategy for the invention located in an engine control unit.
Air flow into the system is filtered by air filter 2 and may pass through a mass air flow (MAF) sensor 3 if fitted. A compressor 4 of a turbocharged system
compresses the air which subsequently passes through an intercooler 5 and a throttle valve 6, before entering the engine 7. A boost (MAP) pressure sensor 8 senses the pressure at the engine intake. Exhaust gases exiting the engine power the turbo 9 and an exhaust brake unit 10 before being passed through exhaust after- treatment units 1 1. In order to provide EGR, an EGR valve 12 and EGR cooler 13 are provided as shown. An ECU control various engine systems including the exhaust brake and EGR valve, and may also monitor MAP and MAF.
An exhaust brake is a means of slowing an engine by closing off the exhaust path from the engine, causing the exhaust gases to be compressed in the exhaust manifold, and in the cylinder. Since the exhaust is being compressed, and there is
no fuel being applied, the engine works backwards, slowing down the vehicle. The amount of negative torque generated is usually directly proportional to the back pressure of the engine. Known applications of the exhaust brake on commercial vehicles, are to slow the vehicle when in gear on tip-out, and to warm the engine faster.
An Engine Control Unit is shown which in aspects of the invention provides the necessary control of the methodologies.
In a simple example of the invention, instead of just passively waiting for the driver to encounter the required operating conditions for the EGR flow to be checked, the exhaust brake which is usually fitted to most trucks, is applied in under certain conditions, where there is no detrimental effect - such as power off conditions, braking conditions (for example when said air brake is usually used) or when the vehicle is in neutral gear and/or any condition when the air brake is conventionally used. Application of the exhaust brake increases the engine back pressure, thus creating conditions conducive for EGR flow and thereby allowing known methods for evaluating the EGR flow to be executed, when they might otherwise not have been able to run.
The situations when the invention will be of benefit, are those that leave the vehicle with acceptable driveability and performance and do not compromise safety. Certainly the window of opportunity will be increased in neutral gear and probably elsewhere too. Known applications of the exhaust brake on commercial vehicles, are to slow the vehicle when in gear on tip-out, and to warm the engine faster.
Alternatively, in other embodiments, an EGR flow check may be forced by applying the exhaust brake even when, for example, the vehicle is in gear. Such methods may be implemented such that (e.g. the torque controller/ECU) the fuelling is adjusted appropriately (by providing more fuel) to compensate for the braking action. So in this manner the method a check can be forced to occur while the vehicle was in gear. This would be a small fuel penalty, but only a very short period is needed (e.g. 1 or 2 seconds) to perform the check. The optional functional block of fuel adjustment is shown in the figure as 15.
The invention allows the range of operating conditions where the EGR flow check can be carried out, to be expanded.
The invention is applicable to engine systems without turbochargers.
Claims
1. A method of monitoring the functionality of an exhaust gas recirculation system/valve in a vehicle engine system which includes an exhaust brake comprising, in one mode of operation:
i) applying said exhaust brake;
ii) monitoring the functionality of the exhaust gas recirculation system only whilst the exhaust brake is applied.
2. A method as claimed in claim 1 wherein said step i) and ii) are performed when the vehicle is in a load off condition or is in neutral gear.
3. A method as claimed in claim 1 wherein steps i) and ii) are performed in gear, and during which fuelling to the engine is adjusted to compensate for the reduction in torque as a result of applying the exhaust brake.
4. A system for monitoring the functionality of an exhaust gas recirculation system/valve in a vehicle engine system which includes an exhaust brake comprising:
i) means to apply said exhaust brake;
ii) means to monitor the functionality of the exhaust gas recirculation system only whilst the exhaust brake is applied.
Applications Claiming Priority (2)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
GB1410197.6 | 2014-06-09 | ||
GBGB1410197.6A GB201410197D0 (en) | 2014-06-09 | 2014-06-09 | Exhaust gas recirculation testing method |
Publications (1)
Publication Number | Publication Date |
---|---|
WO2015189012A1 true WO2015189012A1 (en) | 2015-12-17 |
Family
ID=51266903
Family Applications (1)
Application Number | Title | Priority Date | Filing Date |
---|---|---|---|
PCT/EP2015/061052 WO2015189012A1 (en) | 2014-06-09 | 2015-05-20 | Exhaust gas recirculation testing method |
Country Status (2)
Country | Link |
---|---|
GB (1) | GB201410197D0 (en) |
WO (1) | WO2015189012A1 (en) |
Citations (2)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
JPH11117798A (en) * | 1997-10-09 | 1999-04-27 | Toyota Motor Corp | Exhaust emission control device for internal combustion engine |
JP2010127243A (en) * | 2008-11-28 | 2010-06-10 | Toyota Motor Corp | Failure diagnosing device for internal combustion engine |
-
2014
- 2014-06-09 GB GBGB1410197.6A patent/GB201410197D0/en not_active Ceased
-
2015
- 2015-05-20 WO PCT/EP2015/061052 patent/WO2015189012A1/en active Application Filing
Patent Citations (2)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
JPH11117798A (en) * | 1997-10-09 | 1999-04-27 | Toyota Motor Corp | Exhaust emission control device for internal combustion engine |
JP2010127243A (en) * | 2008-11-28 | 2010-06-10 | Toyota Motor Corp | Failure diagnosing device for internal combustion engine |
Also Published As
Publication number | Publication date |
---|---|
GB201410197D0 (en) | 2014-07-23 |
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