EP0496487A1 - Emission control system - Google Patents
Emission control system Download PDFInfo
- Publication number
- EP0496487A1 EP0496487A1 EP92300045A EP92300045A EP0496487A1 EP 0496487 A1 EP0496487 A1 EP 0496487A1 EP 92300045 A EP92300045 A EP 92300045A EP 92300045 A EP92300045 A EP 92300045A EP 0496487 A1 EP0496487 A1 EP 0496487A1
- Authority
- EP
- European Patent Office
- Prior art keywords
- valve
- gas flow
- exhaust manifold
- exhaust
- flow control
- 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.)
- Granted
Links
Images
Classifications
-
- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F01—MACHINES OR ENGINES IN GENERAL; ENGINE PLANTS IN GENERAL; STEAM ENGINES
- F01N—GAS-FLOW SILENCERS OR EXHAUST APPARATUS FOR MACHINES OR ENGINES IN GENERAL; GAS-FLOW SILENCERS OR EXHAUST APPARATUS FOR INTERNAL COMBUSTION ENGINES
- F01N3/00—Exhaust or silencing apparatus having means for purifying, rendering innocuous, or otherwise treating exhaust
- F01N3/08—Exhaust or silencing apparatus having means for purifying, rendering innocuous, or otherwise treating exhaust for rendering innocuous
- F01N3/10—Exhaust or silencing apparatus having means for purifying, rendering innocuous, or otherwise treating exhaust for rendering innocuous by thermal or catalytic conversion of noxious components of exhaust
- F01N3/18—Exhaust or silencing apparatus having means for purifying, rendering innocuous, or otherwise treating exhaust for rendering innocuous by thermal or catalytic conversion of noxious components of exhaust characterised by methods of operation; Control
- F01N3/22—Control of additional air supply only, e.g. using by-passes or variable air pump drives
- F01N3/227—Control of additional air supply only, e.g. using by-passes or variable air pump drives using pneumatically operated valves, e.g. membrane valves
-
- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F01—MACHINES OR ENGINES IN GENERAL; ENGINE PLANTS IN GENERAL; STEAM ENGINES
- F01N—GAS-FLOW SILENCERS OR EXHAUST APPARATUS FOR MACHINES OR ENGINES IN GENERAL; GAS-FLOW SILENCERS OR EXHAUST APPARATUS FOR INTERNAL COMBUSTION ENGINES
- F01N3/00—Exhaust or silencing apparatus having means for purifying, rendering innocuous, or otherwise treating exhaust
- F01N3/08—Exhaust or silencing apparatus having means for purifying, rendering innocuous, or otherwise treating exhaust for rendering innocuous
- F01N3/10—Exhaust or silencing apparatus having means for purifying, rendering innocuous, or otherwise treating exhaust for rendering innocuous by thermal or catalytic conversion of noxious components of exhaust
- F01N3/18—Exhaust or silencing apparatus having means for purifying, rendering innocuous, or otherwise treating exhaust for rendering innocuous by thermal or catalytic conversion of noxious components of exhaust characterised by methods of operation; Control
- F01N3/22—Control of additional air supply only, e.g. using by-passes or variable air pump drives
-
- 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
- F02M26/52—Systems for actuating EGR valves
- F02M26/55—Systems for actuating EGR valves using vacuum actuators
- F02M26/56—Systems for actuating EGR valves using vacuum actuators having pressure modulation valves
- F02M26/57—Systems for actuating EGR valves using vacuum actuators having pressure modulation valves using electronic means, e.g. electromagnetic valves
-
- 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
- F02M26/45—Sensors specially adapted for EGR systems
- F02M26/46—Sensors specially adapted for EGR systems for determining the characteristics of gases, e.g. composition
- F02M26/47—Sensors specially adapted for EGR systems for determining the characteristics of gases, e.g. composition the characteristics being temperatures, pressures or flow rates
Definitions
- the present invention relates to emission control systems for internal combustion engines.
- valve means is provided to control the rate of flow of exhaust gases to the inlet manifold.
- the valve means may be driven by a vacuum actuator, an electronic control module controlling an electronic vacuum regulator to control the vacuum actuator.
- the engine exhaust system may also be fitted with a catalytic convertor to further reduce pollutants in the exhaust gases.
- air may be pumped to the exhaust manifold, to react with the exhaust gases to preheat the catalyst.
- air is pumped into the exhaust manifold for several minutes after starting the engine and must then be shut down quickly.
- the amount of air mixed with the exhaust gases is critical, too little air prolonging the warming up period and too much air over heating the catalyst so that there is a risk it will melt.
- As the volume of exhaust gases will depend upon the engine speed, it is desirable that the flow of air to the exhaust manifold is modulated to maintain optimum proportions of air and exhaust gases at all engine speeds.
- GB 2,002,548B discloses an internal combustion engine with both exhaust recirculation and secondary air systems in which each system is controlled by a separate gas flow control valve.
- the gas flow control valves are driven by pressure differential from independently regulatable sources and while under common electrical control, it is possible for both valves to be open at the same time thus permitting the secondary air to be fed back to the inlet manifold, which will result in lean running of the engine with possible damage to the engine.
- an emission control system for an internal combustion engine having an inlet manifold, an exhaust manifold and an exhaust system including a catalytic converter comprises; a connection between the exhaust manifold and inlet manifold for recirculating exhaust gases from the exhaust manifold to the inlet manifold, a first gas flow control valve being provided to control flow of exhaust gases from the exhaust manifold to the inlet manifold; a connection to the exhaust manifold by which air may be supplied to the exhaust manifold, a second gas flow control valve being provided to control flow of air to the exhaust manifold, the first and second gas flow control valves each being driven by a fluid pressure differential actuator; characterised in that a common regulatable pressure source is adapted to selectively drive either the first gas flow control valve or the second gas flow control valve.
- Using a common regulatable pressure source to drive both valves in accordance with the present invention will prevent both valves opening at the same time, thus avoiding the risk of damage to the engine due to lean running.
- the present invention will also avoid duplication of the pressure regulating device with consequent reduction in cost and the number of components that can malfunction.
- Figure 1 illustrates diagrammatically an engine 10 with inlet manifold 11 and exhaust manifold 12.
- An exhaust system including a catalytic converter 13 is connected to the exhaust manifold 12.
- the exhaust manifold 12 is connected to the inlet manifold 11 via a first gas flow control valve 14 by which a regulated proportion of the exhaust gases leaving the engine 10 via the exhaust manifold 12 may be recirculated via the inlet manifold 11.
- An air pump 15 is connected to the exhaust manifold 12 via a second gas flow control valve 16, by which a regulated volume of air may be pumped to the exhaust manifold 12.
- the first gas flow control valve 14 has a valve housing 50 which defines a cylindrical valve chamber 51 having an outlet 52 and inlet 53.
- the valve chamber 12 defines a valve seat 54, the valve chamber 51 increasing in diameter from the valve seat 54 to the outlet 52.
- a valve member 56 is located coaxially of the valve chamber 51, a valve stem 57 being slidably mounted in a bearing 58 mounted at the end of the valve chamber 51 remote from the inlet 53.
- a valve head 59 is located at the end of valve stem 57 adjacent to seat 54 so that the valve member 56 may be moved between a position in which the valve head 59 engages and closes the valve seat 54 and a position in which the valve head 59 is spaced axially away from the valve seat 54 towards the outlet 52.
- a cylindrical gas-tight casing 60 is bolted to the valve housing 50 coaxially of the valve chamber 51.
- the end of the valve stem 57 remote from valve head 59 extends into the casing 60.
- the casing 60 is formed from two parts 61 and 62 which are clamped together in suitable manner.
- a flexible annular diaphragm 65 is mounted within the cylindrical casing 60, an outer peripheral bead portion 66 being clamped between parts 61 and 62 of casing 60, to provide a gas-tight seal therebetween.
- the inner periphery 67 of diaphragm 65 is secured to a plate 68 which is mounted on and secured to the end of valve stem 57.
- the diaphragm 65 thereby divides the casing 60 into two gas-tight compartments 70 and 71.
- a port 72 is provided through part 61 of casing 60 to connect compartment 70 to atmosphere, and a port 73 is provided in part 62 of casing 60 by means of which compartment 71 may be connected to a controllable vacuum source.
- a helical compression spring 75 acts between the end of casing 60 remote from valve seat 54 and the plate 68, to apply a load to the valve stem 57 urging the valve head 59 into engagement with valve seat 54.
- the second gas flow control valve 16 as illustrated in Figure 3, comprises a valve housing 111 of similar construction to that of valve 14.
- the valve housing 111 defines a cylindrical valve chamber 112 having an inlet 114 and outlet 115.
- the valve chamber 112 defines a valve seat 113, the valve chamber 112 increasing in diameter from the valve seat 113 towards the inlet 114.
- a valve member 116 is located coaxially of the valve chamber 112, a valve stem 117 being slidably mounted in bearing 118 mounted at the end of valve chamber 112 remote from outlet 115.
- a valve head 119 is located at the end of valve stem 117 adjacent to seat 113, so that the valve member 116 may be moved between a position in which the valve head 119 engages and closes the valve seat 113 and a position in which the valve head 119 is spaced axially away from the valve 113 towards inlet 114.
- a cylindrical gas-tight casing 120 is bolted to the valve housing 111 coaxially of the valve chamber 112.
- the end of the valve stem 117 remote from valve head 119 extends into casing 120.
- the casing 120 is formed from two parts 122 and 123, which are clamped together in suitable manner.
- a flexible annular diaphragm 125 is mounted within the casing 120, an outer peripheral bead portion 126 being clamped between parts 122 and 123 of casing 120, to provide a gas-tight seal therebetween.
- the inner periphery 127 of diaphragm 125 is secured to the valve stem 119 at an axially fixed position. The diaphragm 125 thereby divides the casing 120 into two gas-tight compartments 130 and 131.
- Compartment 130 is connected to the inlet 114 by means of a bore 132 passing through the housing 111 and casing 120 and compartment 131 is connected via inlet 133, pressure tube 134 and bore 135 to the valve chamber 112 on the side of the seat 113 adjacent to the outlet 115.
- a second cylindrical gas-tight casing 140 is bolted to casing 120 with sealing means 141 and a bearing 142 therebetween.
- An extension 143 is secured to the end of valve stem 117 in suitable manner and extends through the bearing 142 into casing 140.
- the casing 140 is formed from two parts 144 and 145, in similar manner to casing 120.
- the outer periphery 147 of a second diaphragm 146 is clamped between parts 144 and 145 of casing 140.
- the inner periphery 148 of diaphragm 146 is secured to a plunger 149 located coaxially within the casing 140.
- a helical compression spring 150 acts between the end of casing 140 remote from valve housing 111 and the plunger 149, to urge the plunger 149 into engagement with an abutment 151 on the end of the extension 143 of valve stem 117, thus applying a load to valve stem 117 which will urge the valve head 119 into engagement with the valve seat 113.
- the diaphragm 146 thereby divides the casing 140 into two gas-tight compartments 152 and 153.
- a port 154 is provided in the wall of part 144 of casing 140 by which compartment 152 is connected to atmosphere and a port 155 is provided in part 145 of casing 140 by which compartment 153 may be connected to a controllable vacuum source.
- Compartments 71 and 153 of valves 14 and 16 respectively are connected by ports 73 and 155, via a vacuum diverter solenoid 20, to an electronic vacuum regulator 21.
- the vacuum diverter solenoid 20 under the control of an electronic control module 22, will selectively connect one of the compartments 71, 153 to the electronic vacuum regulator 21 while connecting the other compartment 153, 71 to atmosphere.
- the electronic vacuum regulator 21 under control of the electronic control module 22, selectively connects the compartment 71, 153 connected thereto, to a source of vacuum or to atmosphere, to regulate the pressure within the compartment 71, 153.
- the electronic control module 22 includes an input circuit 25 for processing signals from sensors 26 to 29, which measure, for example, engine load, engine speed, engine operating temperature and catalyst operating temperature.
- the signals from the sensors 26 to 29 are processed and depending on the parameters measured, the electronic control unit 22 will energise either a secondary air circuit 31 or an exhaust recirculation circuit 32.
- the electronic control unit 22 When the engine is first started and the catalytic converter 13 is cold, the electronic control unit 22 will actuate the secondary air circuit 31.
- the secondary air circuit 31 will switch on the air pump 15 and switch the vacuum diverter solenoid 20, to connect compartment 153 of valve 16 to the electronic vacuum regulator 21 and compartment 71 of valve 14 to atmosphere.
- valve 14 With chambers 70 and 71 of valve 14 connected to atmosphere, the spring 75 will maintain valve head 59 in engagement with the valve seat 54, so that the valve 14 will be closed preventing recirculation of exhaust gases.
- the air pump 15 will deliver air under pressure to the inlet 114 of valve 16.
- the pressure differential across the diaphragm 125 will apply a load to the valve stem 117, urging valve member 116 upwardly against the load applied by spring 150.
- the electronic vacuum regulator 21 will connect chamber 153 to the source of vacuum producing a pressure differential across diaphragm 146 applying an upward load on plunger 149, this upward load opposing the downward load applied by spring 150.
- valve 116 When the loads applied to the valve member 116 by the pressure differential across diaphragm 115 and to the plunger 149 by the pressure differential across diaphragm 146 are in excess of the load applied by the spring 150, the valve 116 will move upwardly opening the valve seat 113 and permitting air to flow from inlet 114 through outlet 115 to the exhaust manifold 12. Because of the varying diameter of the valve chamber 112 the area of the opening between inlet 114 and outlet 115 will depend upon the axial movement of the valve member 116. This may be controlled by controlling the strength of the vacuum in compartment 153 which is achieved by means of the electronic vacuum regulator 21 by switching between vacuum and atmosphere under the control of the electronic control module 22. The degree of opening of valve 16 may thus be controlled to control the proportion of air mixed with the exhaust gases, so that the warming up period of the catalytic converter 13 may be optimised.
- the pressure in compartment 131 will then be in excess of that in compartment 130 and the pressure differential across the diaphragm 125 will move the valve member 116 downwardly, so that the valve head 119 will engage and close the valve seat 113, thereby preventing exhaust gases from being fed back to the pump 15.
- the pressure at the inlet 114 will fall below the pressure at the outlet 115 so that the pressure differential across diaphragm 125 will again close the valve 16 irrespective of the state of the electronic vacuum regulator 21.
- the electronic control module 22 When the catalytic converter 13 has reached its optimum operating temperature, the electronic control module 22 will switch off the secondary air circuit 31 which in turn will de-energise the air pump 15 and will switch the vacuum diverter solenoid so that chamber 71 of valve 14 is connected to the electronic vacuum regulator while chamber 153 of valve 16 is connected to atmosphere.
- valve 16 Connection of chamber 153 of valve 16 to atmosphere will remove the pressure differential across diaphragm 146 re-applying the full load of spring 150 to valve member 116, thus ensuring that the valve 16 remains closed.
- the exhaust gas recirculation circuit 32 will control the electronic vacuum regulator 21 to create a vacuum in compartment 71 of valve 14. Reduction of pressure in compartment 71 of valve 14 will create a pressure differential across diaphragm 65 which will oppose the load applied to the valve member 56 by spring 75, thus moving the valve member 56 upwardly and opening the valve seat 54.
- the axial movement of the valve member 56 and consequently the rate of flow of gases through the valve 14 may be controlled in similar manner to the valve 16, by means of the electronic vacuum regulator 21, so that the proportion of exhaust gas that is recirculated may be controlled in accordance with the operating conditions of the engine.
- a pressure differential transducer 35 measures the pressure across a restriction 36 in the connection between the exhaust manifold 12 and valve 14. This pressure differential transducer 35 provides a signal to a feedback circuit 37 in the electronic control module 22, which will cause the electronic vacuum regulator 21 to connect compartment 71 to atmosphere, shutting valve 14, if the pressure on the downstream side of the restriction 36 falls below that on the upstream side, which would result if pressure in the exhaust manifold 12 fell below that in the inlet manifold 11.
- valves 14 and 16 may be driven by pressure actuators, for example by connecting chambers 70 and 152 to a regulatable source of fluid under pressure and chambers 71 and 153 to atmosphere or drain.
Landscapes
- Engineering & Computer Science (AREA)
- Chemical & Material Sciences (AREA)
- Combustion & Propulsion (AREA)
- Mechanical Engineering (AREA)
- General Engineering & Computer Science (AREA)
- Health & Medical Sciences (AREA)
- Chemical Kinetics & Catalysis (AREA)
- Toxicology (AREA)
- Physics & Mathematics (AREA)
- Electromagnetism (AREA)
- Exhaust Gas After Treatment (AREA)
Abstract
Description
- The present invention relates to emission control systems for internal combustion engines.
- One technique conventionally used to reduce NOx and other pollutants in exhaust gases of internal combustion engines, is to recirculate a proportion of the exhaust gases. The volume of exhaust gases that can be recirculated will depend on the load, speed and operating temperature of the engine. Typically valve means is provided to control the rate of flow of exhaust gases to the inlet manifold. The valve means may be driven by a vacuum actuator, an electronic control module controlling an electronic vacuum regulator to control the vacuum actuator.
- The engine exhaust system may also be fitted with a catalytic convertor to further reduce pollutants in the exhaust gases. In order to reduce the time taken for the catalytic converter to reach its optimum operating temperature when the engine is started up, air may be pumped to the exhaust manifold, to react with the exhaust gases to preheat the catalyst. In such systems, air is pumped into the exhaust manifold for several minutes after starting the engine and must then be shut down quickly. The amount of air mixed with the exhaust gases is critical, too little air prolonging the warming up period and too much air over heating the catalyst so that there is a risk it will melt. As the volume of exhaust gases will depend upon the engine speed, it is desirable that the flow of air to the exhaust manifold is modulated to maintain optimum proportions of air and exhaust gases at all engine speeds.
- GB 2,002,548B discloses an internal combustion engine with both exhaust recirculation and secondary air systems in which each system is controlled by a separate gas flow control valve. The gas flow control valves are driven by pressure differential from independently regulatable sources and while under common electrical control, it is possible for both valves to be open at the same time thus permitting the secondary air to be fed back to the inlet manifold, which will result in lean running of the engine with possible damage to the engine.
- According to one aspect of the present invention an emission control system for an internal combustion engine having an inlet manifold, an exhaust manifold and an exhaust system including a catalytic converter, comprises; a connection between the exhaust manifold and inlet manifold for recirculating exhaust gases from the exhaust manifold to the inlet manifold, a first gas flow control valve being provided to control flow of exhaust gases from the exhaust manifold to the inlet manifold; a connection to the exhaust manifold by which air may be supplied to the exhaust manifold, a second gas flow control valve being provided to control flow of air to the exhaust manifold, the first and second gas flow control valves each being driven by a fluid pressure differential actuator; characterised in that a common regulatable pressure source is adapted to selectively drive either the first gas flow control valve or the second gas flow control valve.
- Using a common regulatable pressure source to drive both valves in accordance with the present invention, will prevent both valves opening at the same time, thus avoiding the risk of damage to the engine due to lean running. The present invention will also avoid duplication of the pressure regulating device with consequent reduction in cost and the number of components that can malfunction.
- An embodiment of the invention is now described, by way of example only, with reference to the accompanying drawings, in which:-
- Figure 1 illustrates diagrammatically an emission control system in accordance with the present invention;
- Figure 2 illustrates diagrammatically the gas flow control valve for controlling flow of exhaust gases from the exhaust manifold to the inlet manifold in the system illustrated in Figure 1; and
- Figure 3 illustrates diagrammatically the gas flow control valve for controlling flow of air to the exhaust manifold of the system illustrated in Figure 1.
- Figure 1 illustrates diagrammatically an
engine 10 withinlet manifold 11 and exhaust manifold 12. An exhaust system including acatalytic converter 13 is connected to the exhaust manifold 12. - The exhaust manifold 12 is connected to the
inlet manifold 11 via a first gasflow control valve 14 by which a regulated proportion of the exhaust gases leaving theengine 10 via the exhaust manifold 12 may be recirculated via theinlet manifold 11. - An
air pump 15 is connected to the exhaust manifold 12 via a second gasflow control valve 16, by which a regulated volume of air may be pumped to the exhaust manifold 12. - As illustrated in Figure 2, the first gas
flow control valve 14 has avalve housing 50 which defines acylindrical valve chamber 51 having anoutlet 52 andinlet 53. The valve chamber 12 defines avalve seat 54, thevalve chamber 51 increasing in diameter from thevalve seat 54 to theoutlet 52. - A
valve member 56 is located coaxially of thevalve chamber 51, avalve stem 57 being slidably mounted in abearing 58 mounted at the end of thevalve chamber 51 remote from theinlet 53. Avalve head 59 is located at the end ofvalve stem 57 adjacent toseat 54 so that thevalve member 56 may be moved between a position in which thevalve head 59 engages and closes thevalve seat 54 and a position in which thevalve head 59 is spaced axially away from thevalve seat 54 towards theoutlet 52. - A cylindrical gas-
tight casing 60 is bolted to thevalve housing 50 coaxially of thevalve chamber 51. The end of thevalve stem 57 remote fromvalve head 59 extends into thecasing 60. Thecasing 60 is formed from twoparts annular diaphragm 65 is mounted within thecylindrical casing 60, an outerperipheral bead portion 66 being clamped betweenparts casing 60, to provide a gas-tight seal therebetween. The inner periphery 67 ofdiaphragm 65 is secured to aplate 68 which is mounted on and secured to the end ofvalve stem 57. Thediaphragm 65 thereby divides thecasing 60 into two gas-tight compartments port 72 is provided throughpart 61 ofcasing 60 to connectcompartment 70 to atmosphere, and aport 73 is provided inpart 62 ofcasing 60 by means of whichcompartment 71 may be connected to a controllable vacuum source. Ahelical compression spring 75 acts between the end ofcasing 60 remote fromvalve seat 54 and theplate 68, to apply a load to thevalve stem 57 urging thevalve head 59 into engagement withvalve seat 54. - The second gas
flow control valve 16, as illustrated in Figure 3, comprises avalve housing 111 of similar construction to that ofvalve 14. Thevalve housing 111 defines acylindrical valve chamber 112 having aninlet 114 andoutlet 115. Thevalve chamber 112 defines avalve seat 113, thevalve chamber 112 increasing in diameter from thevalve seat 113 towards theinlet 114. - A
valve member 116 is located coaxially of thevalve chamber 112, avalve stem 117 being slidably mounted in bearing 118 mounted at the end ofvalve chamber 112 remote fromoutlet 115. Avalve head 119 is located at the end ofvalve stem 117 adjacent toseat 113, so that thevalve member 116 may be moved between a position in which thevalve head 119 engages and closes thevalve seat 113 and a position in which thevalve head 119 is spaced axially away from thevalve 113 towardsinlet 114. - A cylindrical gas-
tight casing 120 is bolted to thevalve housing 111 coaxially of thevalve chamber 112. The end of thevalve stem 117 remote fromvalve head 119 extends intocasing 120. Thecasing 120 is formed from twoparts annular diaphragm 125 is mounted within thecasing 120, an outerperipheral bead portion 126 being clamped betweenparts casing 120, to provide a gas-tight seal therebetween. Theinner periphery 127 ofdiaphragm 125 is secured to thevalve stem 119 at an axially fixed position. Thediaphragm 125 thereby divides thecasing 120 into two gas-tight compartments Compartment 130 is connected to theinlet 114 by means of abore 132 passing through thehousing 111 andcasing 120 andcompartment 131 is connected viainlet 133,pressure tube 134 and bore 135 to thevalve chamber 112 on the side of theseat 113 adjacent to theoutlet 115. - A second cylindrical gas-
tight casing 140 is bolted tocasing 120 with sealing means 141 and a bearing 142 therebetween. Anextension 143 is secured to the end ofvalve stem 117 in suitable manner and extends through the bearing 142 intocasing 140. Thecasing 140 is formed from twoparts outer periphery 147 of asecond diaphragm 146 is clamped betweenparts casing 140. Theinner periphery 148 ofdiaphragm 146 is secured to aplunger 149 located coaxially within thecasing 140. Ahelical compression spring 150 acts between the end ofcasing 140 remote fromvalve housing 111 and theplunger 149, to urge theplunger 149 into engagement with anabutment 151 on the end of theextension 143 ofvalve stem 117, thus applying a load tovalve stem 117 which will urge thevalve head 119 into engagement with thevalve seat 113. Thediaphragm 146 thereby divides thecasing 140 into two gas-tight compartments port 154 is provided in the wall ofpart 144 ofcasing 140 by whichcompartment 152 is connected to atmosphere and aport 155 is provided inpart 145 ofcasing 140 by whichcompartment 153 may be connected to a controllable vacuum source. -
Compartments valves ports vacuum diverter solenoid 20, to anelectronic vacuum regulator 21. Thevacuum diverter solenoid 20 under the control of anelectronic control module 22, will selectively connect one of thecompartments electronic vacuum regulator 21 while connecting theother compartment - The
electronic vacuum regulator 21 under control of theelectronic control module 22, selectively connects thecompartment compartment - The
electronic control module 22 includes aninput circuit 25 for processing signals fromsensors 26 to 29, which measure, for example, engine load, engine speed, engine operating temperature and catalyst operating temperature. The signals from thesensors 26 to 29 are processed and depending on the parameters measured, theelectronic control unit 22 will energise either asecondary air circuit 31 or anexhaust recirculation circuit 32. - When the engine is first started and the
catalytic converter 13 is cold, theelectronic control unit 22 will actuate thesecondary air circuit 31. Thesecondary air circuit 31 will switch on theair pump 15 and switch thevacuum diverter solenoid 20, to connectcompartment 153 ofvalve 16 to theelectronic vacuum regulator 21 andcompartment 71 ofvalve 14 to atmosphere. - With
chambers valve 14 connected to atmosphere, thespring 75 will maintainvalve head 59 in engagement with thevalve seat 54, so that thevalve 14 will be closed preventing recirculation of exhaust gases. - The
air pump 15 will deliver air under pressure to theinlet 114 ofvalve 16. When the pressure at theinlet 114 and incompartment 130 ofvalve 16 is in excess of the pressure at theoutlet 115 and incompartment 131, which will be at the same pressure as the exhaust manifold 12, the pressure differential across thediaphragm 125 will apply a load to thevalve stem 117, urgingvalve member 116 upwardly against the load applied byspring 150. In addition, theelectronic vacuum regulator 21 will connectchamber 153 to the source of vacuum producing a pressure differential acrossdiaphragm 146 applying an upward load onplunger 149, this upward load opposing the downward load applied byspring 150. When the loads applied to thevalve member 116 by the pressure differential acrossdiaphragm 115 and to theplunger 149 by the pressure differential acrossdiaphragm 146 are in excess of the load applied by thespring 150, thevalve 116 will move upwardly opening thevalve seat 113 and permitting air to flow frominlet 114 throughoutlet 115 to the exhaust manifold 12. Because of the varying diameter of thevalve chamber 112 the area of the opening betweeninlet 114 andoutlet 115 will depend upon the axial movement of thevalve member 116. This may be controlled by controlling the strength of the vacuum incompartment 153 which is achieved by means of theelectronic vacuum regulator 21 by switching between vacuum and atmosphere under the control of theelectronic control module 22. The degree of opening ofvalve 16 may thus be controlled to control the proportion of air mixed with the exhaust gases, so that the warming up period of thecatalytic converter 13 may be optimised. - If, for example, the engine should backfire while air is being supplied to the exhaust manifold 12 and the pressure in the exhaust manifold 12 becomes greater than that at the
inlet 114 tovalve 16, the pressure incompartment 131 will then be in excess of that incompartment 130 and the pressure differential across thediaphragm 125 will move thevalve member 116 downwardly, so that thevalve head 119 will engage and close thevalve seat 113, thereby preventing exhaust gases from being fed back to thepump 15. Similarly, if the pump is switched off or should fail, the pressure at theinlet 114 will fall below the pressure at theoutlet 115 so that the pressure differential acrossdiaphragm 125 will again close thevalve 16 irrespective of the state of theelectronic vacuum regulator 21. - When the
catalytic converter 13 has reached its optimum operating temperature, theelectronic control module 22 will switch off thesecondary air circuit 31 which in turn will de-energise theair pump 15 and will switch the vacuum diverter solenoid so thatchamber 71 ofvalve 14 is connected to the electronic vacuum regulator whilechamber 153 ofvalve 16 is connected to atmosphere. - Connection of
chamber 153 ofvalve 16 to atmosphere will remove the pressure differential acrossdiaphragm 146 re-applying the full load ofspring 150 tovalve member 116, thus ensuring that thevalve 16 remains closed. - When the measured parameters of the engine indicate that exhaust gas recirculation would be beneficial, the exhaust
gas recirculation circuit 32 will control theelectronic vacuum regulator 21 to create a vacuum incompartment 71 ofvalve 14. Reduction of pressure incompartment 71 ofvalve 14 will create a pressure differential acrossdiaphragm 65 which will oppose the load applied to thevalve member 56 byspring 75, thus moving thevalve member 56 upwardly and opening thevalve seat 54. The axial movement of thevalve member 56 and consequently the rate of flow of gases through thevalve 14 may be controlled in similar manner to thevalve 16, by means of theelectronic vacuum regulator 21, so that the proportion of exhaust gas that is recirculated may be controlled in accordance with the operating conditions of the engine. - A
pressure differential transducer 35 measures the pressure across arestriction 36 in the connection between the exhaust manifold 12 andvalve 14. This pressuredifferential transducer 35 provides a signal to afeedback circuit 37 in theelectronic control module 22, which will cause theelectronic vacuum regulator 21 to connectcompartment 71 to atmosphere, shuttingvalve 14, if the pressure on the downstream side of therestriction 36 falls below that on the upstream side, which would result if pressure in the exhaust manifold 12 fell below that in theinlet manifold 11. - Various modifications may be made without departing from the invention. For example, while in the system described above a
vacuum diverter solenoid 20 is used to switch between the vacuum actuators ofvalves valves chambers chambers
Claims (9)
- An emission control system for an internal combustion engine (10) having an inlet manifold (11), an exhaust manifold (12) and an exhaust system including a catalytic converter (13) comprising; a connection between the exhaust manifold (12) and inlet manifold (11) for recirculating exhaust gases from the exhaust manifold (12) to the inlet manifold (11), a first gas flow control valve (14) being provided to control flow of exhaust gases from the exhaust manifold (12) to the inlet manifold (11); a connection to the exhaust manifold (12) by which air may be supplied to the exhaust manifold (12), a second gas flow control valve (16) being provided to control flow of air to the exhaust manifold (12), the first and second gas flow control valves (14, 16) each being driven by a fluid pressure differential actuator (60-72; 140-154) characterised in that a common regulatable pressure source (21) is adapted to selectively drive either the first gas flow control valve (14) or the second gas flow control valve (16).
- An emission control system according to Claim 1 characterised in that the exhaust manifold (12) is connected to an air pump (15) via the second gas flow control valve (16).
- An emission control system according to Claim 1 or 2 characterised in that the first and second gas flow control valves (14, 16) are each driven by a vacuum actuator (60-72; 140-154).
- An emission control system according to any one of Claims 1 to 3, characterised in that the actuator (60-72; 140-154) comprises a pair of fluid tight compartments (70,71; 152,153) separated by a flexible diaphragm (65; 146).
- An emission control system according to Claim 4 characterised in that one of the compartments (71; 153) of each of the first and second gas flow control valves (14; 16) is selectively connected to a regulatable fluid source (21) by a motorised valve (20).
- An emission control system according to Claim 5 characterised in that one of the compartments (71; 153) associated with each of the first and second gas flow control valves (14; 16) is selectively connected to a regulatable fluid source (21) by means of a solenoid valve (20).
- An emission control system according to any one of Claims 4 to 6 characterised in that one of the compartments (71; 153) of the actuator (60-72; 140-154) associated with each of the gas flow control valves (14; 16) is selectively connected via a common pressure regulator (21) to a fluid source.
- An emission control system according to Claim 7 characterised in that the valve (20) and pressure regulator (21) are controlled by an electronic control module (22).
- An emission control system according to any one of the preceding claims characterised in that the second gas flow control valve (16) includes means (120-132) to prevent backflow of exhaust gases from the exhaust manifold (12).
Applications Claiming Priority (2)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
GB9101249 | 1991-01-19 | ||
GB9101249A GB2251890A (en) | 1991-01-19 | 1991-01-19 | I.c. engine exhaust emission control |
Publications (2)
Publication Number | Publication Date |
---|---|
EP0496487A1 true EP0496487A1 (en) | 1992-07-29 |
EP0496487B1 EP0496487B1 (en) | 1995-06-28 |
Family
ID=10688750
Family Applications (1)
Application Number | Title | Priority Date | Filing Date |
---|---|---|---|
EP92300045A Expired - Lifetime EP0496487B1 (en) | 1991-01-19 | 1992-01-03 | Emission control system |
Country Status (3)
Country | Link |
---|---|
EP (1) | EP0496487B1 (en) |
DE (1) | DE69203100T2 (en) |
GB (1) | GB2251890A (en) |
Cited By (7)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
EP0574181A1 (en) * | 1992-06-12 | 1993-12-15 | Ford Motor Company Limited | Internal combustion engine with secondary air circuit and exhaust gas recirculation circuit |
EP0926334A3 (en) * | 1997-12-24 | 2000-05-03 | Mannesmann VDO Aktiengesellschaft | Device for recirculating exhaust gas and for preheating an exhaust gas cleaner |
WO2000031402A1 (en) * | 1998-11-25 | 2000-06-02 | Siemens Canada Limited | Integration of sensor, actuator, and regulator valve in an emission control module |
US6116224A (en) * | 1998-05-26 | 2000-09-12 | Siemens Canada Ltd. | Automotive vehicle having a novel exhaust gas recirculation module |
US6138652A (en) * | 1998-05-26 | 2000-10-31 | Siemens Canada Limited | Method of making an automotive emission control module having fluid-power-operated actuator, fluid pressure regulator valve, and sensor |
US6170476B1 (en) | 1998-05-26 | 2001-01-09 | Siemens Canada Ltd. | Internal sensing passage in an exhaust gas recirculation module |
US6230694B1 (en) | 1998-05-26 | 2001-05-15 | Siemens Canada, Ltd. | Calibration and testing of an automotive emission control module |
Families Citing this family (1)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
DE102020116957B3 (en) | 2020-06-26 | 2021-11-11 | Pierburg Gmbh | Air supply control valve for an internal combustion engine |
Citations (3)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US3992878A (en) * | 1975-10-03 | 1976-11-23 | Ford Motor Company | Engine secondary air flow control system |
US4149377A (en) * | 1976-05-24 | 1979-04-17 | Nissan Motor Company, Limited | Internal combustion engine with emission control systems |
US4202173A (en) * | 1978-03-22 | 1980-05-13 | Toyota Jidosha Kogyo Kabushiki Kaisha | Secondary air supplying device of an internal combustion engine |
Family Cites Families (8)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
JPS5028563B1 (en) * | 1969-12-29 | 1975-09-17 | ||
US3757521A (en) * | 1971-04-05 | 1973-09-11 | Chemical Construction Corp | Integrated engine exhaust emission control system |
JPS5232017B2 (en) * | 1972-11-30 | 1977-08-18 | ||
IT996383B (en) * | 1973-05-10 | 1975-12-10 | Pierburg Kg A | CONTROL DEVICE FOR THE RETURN OF EXHAUST GAS IN THE INTAKE PIPES OF AN INTERNAL COMBUSTION ENGINE |
US3950943A (en) * | 1974-05-20 | 1976-04-20 | General Motors Corporation | Air diverter valve |
JPS5430319A (en) * | 1977-08-10 | 1979-03-06 | Nissan Motor Co Ltd | Electronic control internal combustion engine |
US4342194A (en) * | 1980-10-01 | 1982-08-03 | General Motors Corporation | Electric air control switching valve |
JPS57171016A (en) * | 1981-04-11 | 1982-10-21 | Fuji Heavy Ind Ltd | Controlling device for supplying secondary air in internal combustion engine |
-
1991
- 1991-01-19 GB GB9101249A patent/GB2251890A/en not_active Withdrawn
-
1992
- 1992-01-03 DE DE69203100T patent/DE69203100T2/en not_active Expired - Fee Related
- 1992-01-03 EP EP92300045A patent/EP0496487B1/en not_active Expired - Lifetime
Patent Citations (3)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US3992878A (en) * | 1975-10-03 | 1976-11-23 | Ford Motor Company | Engine secondary air flow control system |
US4149377A (en) * | 1976-05-24 | 1979-04-17 | Nissan Motor Company, Limited | Internal combustion engine with emission control systems |
US4202173A (en) * | 1978-03-22 | 1980-05-13 | Toyota Jidosha Kogyo Kabushiki Kaisha | Secondary air supplying device of an internal combustion engine |
Non-Patent Citations (1)
Title |
---|
PATENT ABSTRACTS OF JAPAN vol. 10, no. 372 (M-544)(2429) 11 December 1986 & JP-A-61 164 046 ( NISSAN MOTOR COMPANY LTD. ) 24 July 1986 * |
Cited By (7)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
EP0574181A1 (en) * | 1992-06-12 | 1993-12-15 | Ford Motor Company Limited | Internal combustion engine with secondary air circuit and exhaust gas recirculation circuit |
EP0926334A3 (en) * | 1997-12-24 | 2000-05-03 | Mannesmann VDO Aktiengesellschaft | Device for recirculating exhaust gas and for preheating an exhaust gas cleaner |
US6116224A (en) * | 1998-05-26 | 2000-09-12 | Siemens Canada Ltd. | Automotive vehicle having a novel exhaust gas recirculation module |
US6138652A (en) * | 1998-05-26 | 2000-10-31 | Siemens Canada Limited | Method of making an automotive emission control module having fluid-power-operated actuator, fluid pressure regulator valve, and sensor |
US6170476B1 (en) | 1998-05-26 | 2001-01-09 | Siemens Canada Ltd. | Internal sensing passage in an exhaust gas recirculation module |
US6230694B1 (en) | 1998-05-26 | 2001-05-15 | Siemens Canada, Ltd. | Calibration and testing of an automotive emission control module |
WO2000031402A1 (en) * | 1998-11-25 | 2000-06-02 | Siemens Canada Limited | Integration of sensor, actuator, and regulator valve in an emission control module |
Also Published As
Publication number | Publication date |
---|---|
GB9101249D0 (en) | 1991-02-27 |
GB2251890A (en) | 1992-07-22 |
EP0496487B1 (en) | 1995-06-28 |
DE69203100D1 (en) | 1995-08-03 |
DE69203100T2 (en) | 1995-11-23 |
Similar Documents
Publication | Publication Date | Title |
---|---|---|
US5755101A (en) | Electronic turbocharger wastegate controller | |
US6470866B2 (en) | Diesel engine exhaust gas recirculation (EGR) system and method | |
US4498429A (en) | Fuel intake system for supercharged engine | |
US20120198837A1 (en) | Turbocharger control strategy to increase exhaust manifold pressure | |
US4469079A (en) | Exhaust gas recirculation (EGR) system | |
US20070259226A1 (en) | Fuel Cell System with Variable Coanda Amplifiers for Gas Recirculation and System Pressure Regulation | |
JP3370151B2 (en) | Method and apparatus for inspecting a mechanism for supplying secondary air into an exhaust pipe of an internal combustion engine | |
EP0496487B1 (en) | Emission control system | |
US6886335B2 (en) | Device for preventing the turbo-charger from over-running | |
US4165611A (en) | Secondary air feeding device for an internal combustion engine | |
ES8501054A1 (en) | A regulation device for a turbo compressor unit for supercharging an internal combustion engine. | |
US3983697A (en) | Exhaust gas cleaning system for internal combustion engines | |
US3888080A (en) | Air flow control valve | |
US4669442A (en) | Exhaust gas recirculation apparatus for engine with turbocharger | |
US4170971A (en) | Pneumatic pressure control valve assembly | |
JPS6349067B2 (en) | ||
CA1191756A (en) | Vacuum pressure regulator | |
US4614184A (en) | Single solenoid control of sequential multiple actuators | |
US4141214A (en) | Exhaust gas cleaning apparatus of an internal combustion engine | |
US4154057A (en) | Exhaust gas cleaning apparatus of an internal combustion engine | |
US4211074A (en) | Secondary air supply system for the exhaust system of an internal combustion engine | |
US4785630A (en) | Arrangement for the control of the charging pressure of an exhaust gas turbocharger | |
US6321536B1 (en) | Pneumatically controlled exhaust throttle for delivering EGR on turbocharged engines | |
EP0496497A1 (en) | Gas flow control valve | |
JPH11200959A (en) | Egr valve structure |
Legal Events
Date | Code | Title | Description |
---|---|---|---|
PUAI | Public reference made under article 153(3) epc to a published international application that has entered the european phase |
Free format text: ORIGINAL CODE: 0009012 |
|
AK | Designated contracting states |
Kind code of ref document: A1 Designated state(s): DE FR GB |
|
17P | Request for examination filed |
Effective date: 19921030 |
|
17Q | First examination report despatched |
Effective date: 19931020 |
|
GRAA | (expected) grant |
Free format text: ORIGINAL CODE: 0009210 |
|
AK | Designated contracting states |
Kind code of ref document: B1 Designated state(s): DE FR GB |
|
REF | Corresponds to: |
Ref document number: 69203100 Country of ref document: DE Date of ref document: 19950803 |
|
ET | Fr: translation filed | ||
REG | Reference to a national code |
Ref country code: GB Ref legal event code: 746 Effective date: 19951214 |
|
PLBE | No opposition filed within time limit |
Free format text: ORIGINAL CODE: 0009261 |
|
STAA | Information on the status of an ep patent application or granted ep patent |
Free format text: STATUS: NO OPPOSITION FILED WITHIN TIME LIMIT |
|
26N | No opposition filed | ||
REG | Reference to a national code |
Ref country code: FR Ref legal event code: D9 Free format text: CORRECTION |
|
REG | Reference to a national code |
Ref country code: FR Ref legal event code: TP Ref country code: FR Ref legal event code: CD |
|
PGFP | Annual fee paid to national office [announced via postgrant information from national office to epo] |
Ref country code: GB Payment date: 20011214 Year of fee payment: 11 |
|
PGFP | Annual fee paid to national office [announced via postgrant information from national office to epo] |
Ref country code: DE Payment date: 20011217 Year of fee payment: 11 |
|
PGFP | Annual fee paid to national office [announced via postgrant information from national office to epo] |
Ref country code: FR Payment date: 20011226 Year of fee payment: 11 |
|
REG | Reference to a national code |
Ref country code: GB Ref legal event code: IF02 |
|
PG25 | Lapsed in a contracting state [announced via postgrant information from national office to epo] |
Ref country code: GB Free format text: LAPSE BECAUSE OF NON-PAYMENT OF DUE FEES Effective date: 20030103 |
|
PG25 | Lapsed in a contracting state [announced via postgrant information from national office to epo] |
Ref country code: DE Free format text: LAPSE BECAUSE OF NON-PAYMENT OF DUE FEES Effective date: 20030801 |
|
GBPC | Gb: european patent ceased through non-payment of renewal fee |
Effective date: 20030103 |
|
PG25 | Lapsed in a contracting state [announced via postgrant information from national office to epo] |
Ref country code: FR Free format text: LAPSE BECAUSE OF NON-PAYMENT OF DUE FEES Effective date: 20030930 |
|
REG | Reference to a national code |
Ref country code: FR Ref legal event code: ST |