GB2471840A - Supplying pressurised EGR in an i.c. engine - Google Patents
Supplying pressurised EGR in an i.c. engine Download PDFInfo
- Publication number
- GB2471840A GB2471840A GB0912107A GB0912107A GB2471840A GB 2471840 A GB2471840 A GB 2471840A GB 0912107 A GB0912107 A GB 0912107A GB 0912107 A GB0912107 A GB 0912107A GB 2471840 A GB2471840 A GB 2471840A
- Authority
- GB
- United Kingdom
- Prior art keywords
- egr
- exhaust
- engine
- charging
- exhaust port
- 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.)
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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
-
- 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
- F02M26/09—Constructional details, e.g. structural combinations of EGR systems and supercharger systems; Arrangement of the EGR and supercharger systems with respect to the engine
- F02M26/10—Constructional details, e.g. structural combinations of EGR systems and supercharger systems; Arrangement of the EGR and supercharger systems with respect to the engine having means to increase the pressure difference between the exhaust and intake system, e.g. venturis, variable geometry turbines, check valves using pressure pulsations or throttles in the air intake or exhaust system
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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
- F02M26/13—Arrangement or layout of EGR passages, e.g. in relation to specific engine parts or for incorporation of accessories
- F02M26/14—Arrangement or layout of EGR passages, e.g. in relation to specific engine parts or for incorporation of accessories in relation to the exhaust system
- F02M26/16—Arrangement or layout of EGR passages, e.g. in relation to specific engine parts or for incorporation of accessories in relation to the exhaust system with EGR valves located at or near the connection to the exhaust system
-
- 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
- F02M26/13—Arrangement or layout of EGR passages, e.g. in relation to specific engine parts or for incorporation of accessories
- F02M26/37—Arrangement or layout of EGR passages, e.g. in relation to specific engine parts or for incorporation of accessories with temporary storage of recirculated exhaust gas
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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
- F02M26/13—Arrangement or layout of EGR passages, e.g. in relation to specific engine parts or for incorporation of accessories
- F02M26/38—Arrangement or layout of EGR passages, e.g. in relation to specific engine parts or for incorporation of accessories with two or more EGR valves disposed in parallel
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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
- F02M26/13—Arrangement or layout of EGR passages, e.g. in relation to specific engine parts or for incorporation of accessories
- F02M26/42—Arrangement or layout of EGR passages, e.g. in relation to specific engine parts or for incorporation of accessories having two or more EGR passages; EGR systems specially adapted for engines having two or more cylinders
- F02M26/44—Arrangement or layout of EGR passages, e.g. in relation to specific engine parts or for incorporation of accessories having two or more EGR passages; EGR systems specially adapted for engines having two or more cylinders in which a main EGR passage is branched into multiple passages
Landscapes
- Engineering & Computer Science (AREA)
- Chemical & Material Sciences (AREA)
- Combustion & Propulsion (AREA)
- Mechanical Engineering (AREA)
- General Engineering & Computer Science (AREA)
- Exhaust-Gas Circulating Devices (AREA)
- Output Control And Ontrol Of Special Type Engine (AREA)
Abstract
In order to supply pressurised EGR in a multi-cylinder internal combustion engine, especially a supercharged or turbocharged engine, the opening of an exhaust port throttle valve 14 is reduced to increase the peak of the rising exhaust back pressure within the throttled exhaust port 12 during the exhaust stroke of the cylinder sufficiently to drive cyclically a pulse of pressurised exhaust gases at an instantaneous pressure higher than the mean gas pressure of the engine exhaust system from the throttled exhaust port 12 via a non-return EGR charging valve 16 located in an EGR charging pipe 18 through to an EGR gas chamber 20. A continuous flow of EGR gas is then delivered from the EGR gas chamber 20 into the intake system 26 of the engine via an EGR dispensing pipe 22. A flow regulating valve 24 may be provided in the EGR dispensing pipe 22. An additional EGR pipe (19, fig.2) may be provided to connect the main exhaust system 28 to the EGR gas chamber 20 via a non-return valve (17).
Description
METHOD FOR SUPPLYING PRESSURISED EGR IN IC ENGINE
Field of the invention
The present invention relates to a method of supplying pressurised EGR in an internal combustion engine.
Background of the invention
EGR (Exhaust Gas Recirculation) is commonly used for reducing the NOx emissions and slowing down the combustion rate of an internal combustion engine. In the case where the engine is supplied with pressurised air from a supercharger or turbocharger, it is necessary to provide the EGR at an elevated pressure higher than the pressure of the air supply to the engine in order to introduce the EGR into the intake system of the engine. This is conventionally achieved by increasing the mean back pressure in the engine exhaust system which has the disadvantage of increasing the pumping work and reducing the fuel efficiency of the engine.
Moreover, such method is also at times unreliable because the instantaneous pressures in the engine exhaust and intake systems are highly variable and the instantaneous pressure difference could change or even reverse very rapidly under dynamic driving conditions.
Aim of the invention The present invention aims to achieve a reliable and efficient method and system for delivering the EGR.
Summary of the invention
According to a first aspect of the present invention, there is provided a method for supplying pressurised EGR in a multi-cylinder internal combustion engine comprising the steps of providing an exhaust port throttle valve in the exhaust port of at least one cylinder of the engine, reducing the opening of the port throttle valve in order to increase the peak of the rising exhaust back pressure within the throttled exhaust port during the exhaust stroke of the cylinder sufficiently to drive cyclically a pulse of pressurised exhaust gases at an instantaneous pressure higher than the mean gas pressure of the engine exhaust system from the throttled exhaust port via a non-return EGR charging valve located in an EGR charging pipe through to an EGR gas chamber, and delivering from the EGR gas chamber via an EGR dispensing pipe a continuous flow of exhaust gases into the intake system of the engine.
According to a second aspect of the present invention, there is provided a system for supplying pressurised EGR in a multi-cylinder internal combustion engine comprising an exhaust port throttle valve located in the exhaust port of at least one cylinder of the engine, means for reducing the opening of the port throttle valve in order to increase the peak of the rising exhaust back pressure within the throttled exhaust port during the exhaust stroke of the cylinder sufficiently to drive cyclically a pulse of pressurised exhaust gases at an instantaneous pressure higher than the mean gas pressure of the engine exhaust system from the throttled exhaust port via a non-return EGR charging valve located in an EGR charging pipe through to an EGR gas chamber, the said non-return EGR charging valve, EGR charging pipe and EGR gas chamber, and an EGR dispensing pipe delivering a continuous flow of exhaust gases from the EGR gas chamber into the intake system of the engine.
In order to ensure uniform distribution of EGR to all the cylinders, it is preferred that more than one cylinders are used to supply the pressurised EGR in which case more than one EGR charging pipes are connected to a common EGR gas chamber.
The intake system of the engine is herein defined as any part of the engine connected to the intake air supply to the engine. This includes the intake manifold, the intake ports and the engine cylinders when the intake valve to each cylinder is open. When the EGR gases are introduced into the upstream region of the intake manifold, they are mixed with the incoming air and distributed between the cylinders.
When the EGR gases are introduced separately into the intake ducts or intake ports of the cylinders, they will backfill the intake ducts during the non-induction strokes of the cylinders and the temporarily stored EGR gases will move into the cylinders during the induction strokes of the cylinders followed by air going into the cylinders as well as more EGR gases going into the cylinder.
The non-return EGR charging valve will permit flow of exhaust gases from the throttled exhaust port to the EGR gas chamber when the gas pressure in the exhaust port is higher than the gas pressure in the EGR gas chamber, and prevent any leakage of exhaust gases from the EGR gas chamber back into the exhaust port when the gas pressure in the EGR gas chamber is higher than the gas pressure in the exhaust port.
In the invention, because the charging of the EGR gas chamber is achieved by pressure pulses built up briefly and cyclically within the throttled exhaust port during the exhaust stroke of the cylinder (herein called active EGR), a substantial gas pressure higher than the mean gas pressure in the exhaust system of the engine is available for driving the EGR gases into the intake system of the engine.
Within the throttled exhaust port, the time-averaged exhaust back pressure during the entire exhaust stroke of the cylinder is relatively low and therefore the mean pumping work experienced by the cylinder is also relatively low. Moreover, the mean gas pressure in the main exhaust system of the engine is not significantly affected by the throttling of the exhaust port in the individual cylinder so that the mean pumping work experienced by the remaining cylinders is also relatively low. Thus the overall fuel efficiency of the engine will not be significantly affected when the pressurised EGR is supplied to the engine according to the method and system of the present invention.
Preferably, in order to produce the maximum charging of exhaust gases into the EGR gas chamber, the exhaust port throttle valve is positioned close to the exhaust valve of the cylinder and the non-return charging valve is positioned close to the exhaust port of the cylinder so that the volume occupied by the exhaust port bounded by the throttle valve and the non-return valve is small in relation with the swept volume of the cylinder. The smaller the volume of the throttled exhaust port in relation with the swept volume of cylinder, the higher the peak charging pressure generated during the exhaust stroke of the cylinder.
The quantity of EGR gases delivered to the engine may be regulated by adjusting the exhaust port throttle valve which varies the magnitude of the charging exhaust pulses into the EGR gas chamber. Subsequent to that, the length of the EGR dispensing pipe will substantially damp out the pressure fluctuations created in the EGR gas chamber so that a smooth EGR gas flow will emerge from the exit end of the EGR dispensing pipe. In general for a given mean EGR gas flow, the magnitude of pressure fluctuations in the flow will be smaller if there are many cylinders charging exhaust gases in smaller pulses more frequently into the EGR gas chamber compared with less cylinders charging exhaust gases in bigger pulses less frequently into the chamber. The smaller the magnitude of pressure fluctuations, the smoother the EGR gas flow to the engine. Thus it is desirable to use as many cylinders as possible, and preferably all the cylinders of the engine, for producing the active EGR.
The present invention will automatically work as a conventional EGR system (herein called passive EGR) when a mean pressure drop falling towards the engine intake system is available, i.e. when the mean gas pressure in the exhaust system is higher than the mean air pressure in the intake system.
In the combined active and passive EGR system, an EGR flow regulating valve is provided in the EGR dispensing pipe. When the mean pressure drop is in the direction of the engine intake system, the non-return charging valve will automatically open allowing a steady stream of exhaust gases to flow via the EGR charging pipe, the EGR flow regulating valve and the EGR dispensing pipe into the intake system thus providing passive EGR.
An additional EGR pipe may also be provided connecting the main exhaust system of the engine to the EGR gas chamber together with a non-return valve for permitting flow of exhaust gas from the main exhaust system into the EGR gas chamber and for blocking any reverse flow of exhaust gases from the EGR gas chamber to the main exhaust system. In this case, the non-return valve in the EGR pipe duplicates the function of the non-return charging valve in the EGR charging pipe of the active EGR system.
In operation, when a mean pressure drop falling towards the engine intake system is not available, the EGR flow regulating valve is fully open while the active EGR system is activated and the quantity of EGR gases delivered to the intake system of the engine is regulated by adjusting the exhaust port throttle valve which varies the magnitude of the charging exhaust pulses into the EGR gas chamber.
When a mean pressure drop falling towards the engine intake system is available, the EGR flow regulating valve is variable for regulating the quantity of EGR gases delivered to the intake system of the engine while the active EGR system is deactivated with the exhaust port throttle valve fully open creating no charging pulses.
When a higher EGR flow is required than can be provided by the available mean pressure drop falling towards the engine intake system, the active EGR system is activated and the quantity of EGR gases delivered to the intake system of the engine is regulated by adjusting the exhaust port throttle valve or by adjusting both the exhaust port throttle valve and the EGR flow regulating valve.
An EGR flow meter may be provided in the EGR dispensing pipe for used in both the active and passive EGR systems.
An EGR cooler may also be provided along the EGR dispensing pipe for cooling the EGR gases. Alternatively an EGR cooler may be integrated within the EGR gas chamber for cooling the EGR gases.
In a naturally aspirated spark ignition engine operating at high load, there is little manifold vacuum in the unthrottled intake system for drawing EGR into the engine and there may not be sufficient back pressure in the exhaust system for driving a high rate of EGR into the engine. The present invention makes it possible to supply reliably a high rate of EGR to the engine even at wide-open-throttle conditions.
In a pressure charged internal combustion engine, the present invention can provide a high rate of pressurised EGR into the boosted intake system of the engine even though the mean gas pressure in the engine exhaust system may not be high enough to overcome the air pressure in the intake system. At the same time the non-return charging valves in the EGR charging pipes and the non-return valve in the EGR pipe will prevent any pressurised air from entering the engine exhaust system.
The present invention is suitable for application in any pressure charged engine supplied with pressurised air from a supercharger and/or turbocharger. It is also suitable for application in a pressure charged engine supplied with pressurised air from a pressurised air storage tank onboard an air hybrid vehicle.
Brief description of the drawings
The invention will now be described further by way of example with reference to the accompanying drawings in which Figure 1 is a schematic illustration of a system for supplying pressurised EGR in a multi-cylinder internal combustion engine according to the present invention, and Figure 2 is a schematic illustration of a variation of the system shown in Figure 1.
Detailed description of the preferred embodiment
Figure 1 shows a cylinder 10 of a multi-cylinder internal combustion engine having intake and exhaust valves cyclically connecting the cylinder 10 with an intake system 26 and exhaust system 28 respectively.
In the invention, the method for supplying pressurised EGR to the intake system 26 of engine comprises the steps of providing an exhaust port throttle valve 14 in the exhaust port 12 of at least one cylinder 10 of the engine, reducing the opening of the port throttle valve 14 in order to increase the peak of the rising exhaust back pressure within the throttled exhaust port 12 during the exhaust stroke of the cylinder 10 sufficiently to drive cyclically a pulse of pressurised exhaust gases at an instantaneous pressure higher than the mean gas pressure of the engine exhaust system 28 from the throttled exhaust port 12 via a non-return EGR charging valve 16 located in an EGR charging pipe 18 through to an EGR gas chamber 20, and delivering from the EGR gas chamber 20 via an EGR dispensing pipe 22 a continuous flow of exhaust gases into the intake system 26 of the engine.
In order to ensure uniform distribution of EGR to all the cylinders, it is preferred that more than one cylinders are used to supply the pressurised EGR in which case more than one EGR charging pipes (not shown) are connected to a common EGR gas chamber.
The intake system 24 of the engine is herein defined as any part of the engine connected to the intake air supply to the engine. This includes the intake manifold, the intake ports and the engine cylinders when the intake valve to each cylinder is open.
The non-return EGR charging valve 16 will permit flow of exhaust gases from the throttled exhaust port 12 to the EGR gas chamber 20 when the gas pressure in the exhaust port 12 is higher than the gas pressure in the EGR gas chamber 20, and prevent any leakage of exhaust gases from the EGR gas chamber 20 back into the exhaust port 12 when the gas pressure in the EGR gas chamber 20 is higher than the gas pressure in the exhaust port 12.
In the invention, because the charging of the EGR gas chamber 20 is achieved by pressure pulses built up briefly and cyclically within the throttled exhaust port 12 during the exhaust stroke of the cylinder 10 (herein called active EGR), a substantial gas pressure higher than the mean gas pressure in the exhaust system 28 of the engine is available for driving the EGR gases into the intake system 26 of the engine.
Within the throttled exhaust port 12, the time-averaged exhaust back pressure during the entire exhaust stroke of the cylinder 10 is relatively low and therefore the mean pumping work experienced by the cylinder 10 is also relatively low. Moreover, the mean gas pressure in the main exhaust system 28 of the engine is not significantly affected by the throttling of the exhaust port 12 in the individual cylinder 10 so that the mean pumping work experienced by the remaining cylinders is also relatively low. Thus the overall fuel efficiency of the engine will not be significantly affected when the pressurised EGR is supplied to the engine according to the method of the present invention.
Preferably, in order to produce the maximum charging of exhaust gases into the EGR gas chamber 20, the exhaust port throttle valve 14 is positioned close to the exhaust valve of the cylinder 10 and the non-return charging valve 16 is positioned close to the exhaust port 12 of the cylinder 10 so that the volume occupied by the exhaust port 12 bounded by the throttle valve 14 and the non-return valve 16 is small in relation with the swept volume of the cylinder 10.
The smaller the volume of the throttled exhaust port 12 in relation with the swept volume of cylinder 10, the higher the peak charging pressure generated during the exhaust stroke of the cylinder 10.
The quantity of EGR gases delivered to the engine may be regulated by adjusting the exhaust port throttle valve 14 which varies the magnitude of the charging exhaust pulses into the EGR gas chamber 20. Subsequent to that, the length of the EGR dispensing pipe 22 will substantially damp out the pressure fluctuations created in the EGR gas chamber 20 so that a smooth EGR gas flow will emerge from the exit end of the EGR dispensing pipe 22. In general for a given mean EGR gas flow, the magnitude of pressure fluctuations will be smaller if there are many cylinders charging exhaust gases -10 -in smaller pulses more frequently into the EGR gas chamber compared with less cylinders charging exhaust gases in bigger pulses less frequently into the chamber 20. The smaller the magnitude of pressure fluctuations, the smoother the EGR gas flow to the engine. Thus it is desirable to use as many cylinders as possible, and preferably all the cylinders of the engine, for producing the active EGR.
The present invention will automatically work as a conventional EGR system (herein called passive EGR) when a mean pressure drop falling towards the engine intake system is available, i.e. when the mean gas pressure in the exhaust system is higher than the mean air pressure in the intake system.
In Figure 1, an EGR flow regulating valve 24 is provided in the EGR dispensing pipe 22. When the mean pressure drop is in the direction of the engine intake system 26, the non-return charging valve 16 will automatically open allowing a steady stream of exhaust gases to flow via the EGR charging pipe 18, the EGR flow regulating valve 24 and the EGR dispensing pipe 22 into the intake system 26 thus providing passive EGR.
In Figure 2, an additional EGR pipe 19 is provided connecting the main exhaust system 28 of the engine to the EGR gas chamber 20 together with a non-return valve 17 in the EGR pipe 19 for permitting flow of exhaust gas from the main exhaust system 28 into the EGR gas chamber 20 and for blocking any reverse flow of exhaust gases from the EGR gas chamber 20 to the main exhaust system 28. In this case, the non-return valve 17 in the EGR pipe 19 duplicates the function of the non-return charging valve 16 in the EGR charging pipe 18 of the active EGR system.
In operation in both Figures 1 and 2, when a mean pressure drop falling towards the engine intake system 26 is -11 -not available, the EGR flow regulating valve 24 is fully open while the active EGR system is activated and the quantity of EGR gases delivered to the intake system 26 of the engine is regulated by adjusting the exhaust port throttle valve 14 which varies the magnitude of the charging exhaust pulses into the EGR gas chamber 20. When a mean pressure drop falling towards the engine intake system 26 is available, the EGR flow regulating valve 24 is variable for regulating the quantity of EGR gases delivered to the intake system 26 of the engine while the active EGR system is deactivated with the exhaust port throttle valve 14 fully open creating no charging pulses.
When a higher EGR flow is required than can be provided by the available mean pressure drop falling towards the engine intake system 26, the active EGR system is activated and the quantity of EGR gases delivered to the intake system 26 of the engine is regulated by adjusting the exhaust port throttle valve 14 or by adjusting both the exhaust port throttle valve 14 and the EGR flow regulating valve 24.
An EGR flow meter (not shown) may be provided in the EGR dispensing pipe 22 for used in both the active and passive EGR systems.
An EGR cooler (not shown) may also be provided along the EGR dispensing pipe 22 for cooling the EGR gases.
Alternatively an EGR cooler may be integrated within the EGR gas chamber 20 for cooling the EGR gases.
In a naturally aspirated spark ignition engine operating at high load, there is little manifold vacuum in the unthrottled intake system 26 for drawing EGR into the engine and there may not be sufficient back pressure in the exhaust system 28 for driving a high rate of EGR into the engine. The present invention makes it possible to supply -12 - reliably a high rate of EGR to the engine even at wide-open-throttle conditions.
In a pressure charged internal combustion engine, the present invention can provide a high rate of pressurised EGR into the boosted intake system 26 of the engine even though the mean gas pressure in the engine exhaust system 28 may not be high enough to overcome the air pressure in the intake system 26. At the same time the non-return charging valves 16 in the EGR charging pipes 18 and the non-return valve 17 in the EGR pipe 19 will prevent any pressurised air from entering the engine exhaust system 28.
Thus the present invention is suitable for application in any pressure charged engine supplied with pressurised air from a supercharger and/or turbocharger. It is also suitable for application in a pressure charged engine supplied with pressurised air from a pressurised air storage tank onboard an air hybrid vehicle.
Claims (12)
- -13 -CLAIMS1. A method for supplying pressurised EGR in a multi-cylinder internal combustion engine comprising the steps of providing an exhaust port throttle valve in the exhaust port of at least one cylinder of the engine, reducing the opening of the port throttle valve in order to increase the peak of the rising exhaust back pressure within the throttled exhaust port during the exhaust stroke of the cylinder sufficiently to drive cyclically a pulse of pressurised exhaust gases at an instantaneous pressure higher than the mean gas pressure of the engine exhaust system from the throttled exhaust port via a non-return EGR charging valve located in an EGR charging pipe through to an EGR gas chamber, and delivering from the EGR gas chamber via an EGR dispensing pipe a continuous flow of exhaust gases into the intake system of the engine.
- 2. A system for supplying pressurised EGR in a multi-cylinder internal combustion engine comprising an exhaust port throttle valve located in the exhaust port of at least one cylinder of the engine, means for reducing the opening of the port throttle valve in order to increase the peak of the rising exhaust back pressure within the throttled exhaust port during the exhaust stroke of the cylinder sufficiently to drive cyclically a pulse of pressurised exhaust gases at an instantaneous pressure higher than the mean gas pressure of the engine exhaust system from the throttled exhaust port via a non-return EGR charging valve located in an EGR charging pipe through to an EGR gas chamber, the said non-return EGR charging valve, EGR charging pipe and EGR gas chamber, and an EGR dispensing pipe delivering a continuous flow of exhaust gases from the EGR gas chamber into the intake system of the engine.
- 3. A system as claimed in claim 2, wherein in order to produce the maximum charging of exhaust gases into the -14 -EGR gas chamber, the exhaust port throttle valve is positioned close to the exhaust valve of the cylinder and the non-return charging valve is positioned close to the exhaust port of the cylinder so that the volume occupied by the exhaust port bounded by the throttle valve and the non-return valve is small in relation with the swept volume of the cylinder.
- 4. A system as claimed in claim 2 or 3, wherein more than one cylinders are used to supply the pressurised EGR and more than one EGR charging pipes are connected to a common EGR gas chamber.
- 5. A system as claimed in claim 2 or 4, wherein the length of the EGR dispensing pipe is such that it substantially damps out the pressure fluctuations created in the EGR gas chamber so that a smooth EGR gas flow will emerge from the exit end of the EGR dispensing pipe.
- 6. A system as claimed in any one of claims 2 to 5, wherein an EGR flow regulating valve is provided in the EGR dispensing pipe.
- 7. A system as claimed in any one of claims 2 to 6, wherein an additional EGR pipe is provided connecting the main exhaust system of the engine to the EGR gas chamber together with a non-return valve in the EGR pipe for permitting flow of exhaust gas from the main exhaust system into the EGR gas chamber and for blocking any reverse flow of exhaust gases from the EGR gas chamber to the main exhaust system.
- 8. A system as claimed in claim 6 or 7, wherein when a mean pressure drop falling towards the engine intake system is not available, the EGR flow regulating valve is fully open while the exhaust gas charging system is activated and the quantity of EGR gases delivered to the -15 -intake system of the engine is regulated by adjusting the exhaust port throttle valve which varies the magnitude of the charging exhaust pulses into the EGR gas chamber.
- 9. A system as claimed in claim 6 or 7, wherein when a mean pressure drop falling towards the engine intake system is available, the EGR flow regulating valve is variable for regulating the quantity of EGR gases delivered to the intake system of the engine while the exhaust gas charging system is deactivated with the exhaust port throttle valve fully open creating no charging pulses.
- 10. A system as claimed in claim 6 or 7, wherein when a higher EGR flow is required than can be provided by the available mean pressure drop falling towards the engine intake system, the exhaust gas charging system is activated and the quantity of EGR gases delivered to the intake system of the engine is regulated by adjusting the exhaust port throttle valve or by adjusting both the exhaust port throttle valve and the EGR flow regulating valve.
- 11. A system as claimed in any one of claims 2 to 10, wherein the engine is a pressure charged engine supplied with pressurised air from a supercharger and/or turbocharger.
- 12. A system as claimed in any one of claims 2 to 10, wherein the engine is a pressure charged engine supplied with pressurised air from a pressurised air storage tank onboard an air hybrid vehicle.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| GB0912107A GB2471840A (en) | 2009-07-13 | 2009-07-13 | Supplying pressurised EGR in an i.c. engine |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| GB0912107A GB2471840A (en) | 2009-07-13 | 2009-07-13 | Supplying pressurised EGR in an i.c. engine |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| GB0912107D0 GB0912107D0 (en) | 2009-08-19 |
| GB2471840A true GB2471840A (en) | 2011-01-19 |
Family
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Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| GB0912107A Withdrawn GB2471840A (en) | 2009-07-13 | 2009-07-13 | Supplying pressurised EGR in an i.c. engine |
Country Status (1)
| Country | Link |
|---|---|
| GB (1) | GB2471840A (en) |
Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN102251861A (en) * | 2011-06-10 | 2011-11-23 | 天津大学 | Controlled exhaust backpressure valve for engine |
| CN108005816A (en) * | 2017-12-28 | 2018-05-08 | 潍柴动力股份有限公司 | A kind of engine exhaust-gas recirculating system |
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|---|---|---|---|---|
| EP0531277A2 (en) * | 1991-09-02 | 1993-03-10 | AVL Gesellschaft für Verbrennungskraftmaschinen und Messtechnik mbH.Prof.Dr.Dr.h.c. Hans List | Internal combustion engine having an inlet and outlet system, a turbocharger and a pressure accumulator |
| JPH08232771A (en) * | 1995-02-28 | 1996-09-10 | Suzuki Motor Corp | Exhaust gas recirculation device |
| FR2784419A1 (en) * | 1998-10-13 | 2000-04-14 | Axel Leona Georges M Thienpont | Method for recovering energy from engine brake group involves re-injecting stored exhaust gases into cylinder when accelerating |
| EP1308614A1 (en) * | 2001-10-31 | 2003-05-07 | Peugeot Citroen Automobiles SA | Drive system for motor vehicles |
| DE10210202C1 (en) * | 2002-03-07 | 2003-11-13 | Man B & W Diesel Ag | reciprocating internal combustion engine |
-
2009
- 2009-07-13 GB GB0912107A patent/GB2471840A/en not_active Withdrawn
Patent Citations (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| EP0531277A2 (en) * | 1991-09-02 | 1993-03-10 | AVL Gesellschaft für Verbrennungskraftmaschinen und Messtechnik mbH.Prof.Dr.Dr.h.c. Hans List | Internal combustion engine having an inlet and outlet system, a turbocharger and a pressure accumulator |
| JPH08232771A (en) * | 1995-02-28 | 1996-09-10 | Suzuki Motor Corp | Exhaust gas recirculation device |
| FR2784419A1 (en) * | 1998-10-13 | 2000-04-14 | Axel Leona Georges M Thienpont | Method for recovering energy from engine brake group involves re-injecting stored exhaust gases into cylinder when accelerating |
| EP1308614A1 (en) * | 2001-10-31 | 2003-05-07 | Peugeot Citroen Automobiles SA | Drive system for motor vehicles |
| DE10210202C1 (en) * | 2002-03-07 | 2003-11-13 | Man B & W Diesel Ag | reciprocating internal combustion engine |
Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN102251861A (en) * | 2011-06-10 | 2011-11-23 | 天津大学 | Controlled exhaust backpressure valve for engine |
| CN108005816A (en) * | 2017-12-28 | 2018-05-08 | 潍柴动力股份有限公司 | A kind of engine exhaust-gas recirculating system |
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| GB0912107D0 (en) | 2009-08-19 |
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