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GB2341892A - Controlling exhaust valves of an I.C. engine to reduce time for catalytic converter light-off - Google Patents

Controlling exhaust valves of an I.C. engine to reduce time for catalytic converter light-off Download PDF

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Publication number
GB2341892A
GB2341892A GB9820598A GB9820598A GB2341892A GB 2341892 A GB2341892 A GB 2341892A GB 9820598 A GB9820598 A GB 9820598A GB 9820598 A GB9820598 A GB 9820598A GB 2341892 A GB2341892 A GB 2341892A
Authority
GB
United Kingdom
Prior art keywords
exhaust
predetermined period
engine
exhaust valves
valves
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.)
Withdrawn
Application number
GB9820598A
Other versions
GB9820598D0 (en
Inventor
John William Hitchman
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
MG Rover Group Ltd
Original Assignee
MG Rover Group Ltd
Priority date (The priority date 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 date listed.)
Filing date
Publication date
Application filed by MG Rover Group Ltd filed Critical MG Rover Group Ltd
Priority to GB9820598A priority Critical patent/GB2341892A/en
Publication of GB9820598D0 publication Critical patent/GB9820598D0/en
Publication of GB2341892A publication Critical patent/GB2341892A/en
Withdrawn legal-status Critical Current

Links

Classifications

    • FMECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F02COMBUSTION ENGINES; HOT-GAS OR COMBUSTION-PRODUCT ENGINE PLANTS
    • F02DCONTROLLING COMBUSTION ENGINES
    • F02D13/00Controlling the engine output power by varying inlet or exhaust valve operating characteristics, e.g. timing
    • F02D13/02Controlling the engine output power by varying inlet or exhaust valve operating characteristics, e.g. timing during engine operation
    • F02D13/0203Variable control of intake and exhaust valves
    • FMECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F02COMBUSTION ENGINES; HOT-GAS OR COMBUSTION-PRODUCT ENGINE PLANTS
    • F02DCONTROLLING COMBUSTION ENGINES
    • F02D13/00Controlling the engine output power by varying inlet or exhaust valve operating characteristics, e.g. timing
    • F02D13/02Controlling the engine output power by varying inlet or exhaust valve operating characteristics, e.g. timing during engine operation
    • F02D13/0242Variable control of the exhaust valves only
    • FMECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F02COMBUSTION ENGINES; HOT-GAS OR COMBUSTION-PRODUCT ENGINE PLANTS
    • F02DCONTROLLING COMBUSTION ENGINES
    • F02D13/00Controlling the engine output power by varying inlet or exhaust valve operating characteristics, e.g. timing
    • F02D13/02Controlling the engine output power by varying inlet or exhaust valve operating characteristics, e.g. timing during engine operation
    • F02D13/0253Fully variable control of valve lift and timing using camless actuation systems such as hydraulic, pneumatic or electromagnetic actuators, e.g. solenoid valves
    • FMECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F02COMBUSTION ENGINES; HOT-GAS OR COMBUSTION-PRODUCT ENGINE PLANTS
    • F02DCONTROLLING COMBUSTION ENGINES
    • F02D13/00Controlling the engine output power by varying inlet or exhaust valve operating characteristics, e.g. timing
    • F02D13/02Controlling the engine output power by varying inlet or exhaust valve operating characteristics, e.g. timing during engine operation
    • F02D13/0257Independent control of two or more intake or exhaust valves respectively, i.e. one of two intake valves remains closed or is opened partially while the other is fully opened
    • FMECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F02COMBUSTION ENGINES; HOT-GAS OR COMBUSTION-PRODUCT ENGINE PLANTS
    • F02FCYLINDERS, PISTONS OR CASINGS, FOR COMBUSTION ENGINES; ARRANGEMENTS OF SEALINGS IN COMBUSTION ENGINES
    • F02F1/00Cylinders; Cylinder heads 
    • F02F1/24Cylinder heads
    • F02F1/42Shape or arrangement of intake or exhaust channels in cylinder heads
    • F02F1/4214Shape or arrangement of intake or exhaust channels in cylinder heads specially adapted for four or more valves per cylinder
    • FMECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F02COMBUSTION ENGINES; HOT-GAS OR COMBUSTION-PRODUCT ENGINE PLANTS
    • F02DCONTROLLING COMBUSTION ENGINES
    • F02D13/00Controlling the engine output power by varying inlet or exhaust valve operating characteristics, e.g. timing
    • F02D13/02Controlling the engine output power by varying inlet or exhaust valve operating characteristics, e.g. timing during engine operation
    • F02D2013/0292Controlling the engine output power by varying inlet or exhaust valve operating characteristics, e.g. timing during engine operation in the start-up phase, e.g. for warming-up cold engine or catalyst
    • YGENERAL 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
    • Y02TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
    • Y02TCLIMATE CHANGE MITIGATION TECHNOLOGIES RELATED TO TRANSPORTATION
    • Y02T10/00Road transport of goods or passengers
    • Y02T10/10Internal combustion engine [ICE] based vehicles
    • Y02T10/12Improving ICE efficiencies

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  • Engineering & Computer Science (AREA)
  • Chemical & Material Sciences (AREA)
  • Combustion & Propulsion (AREA)
  • Mechanical Engineering (AREA)
  • General Engineering & Computer Science (AREA)
  • Physics & Mathematics (AREA)
  • Electromagnetism (AREA)
  • Valve Device For Special Equipments (AREA)
  • Output Control And Ontrol Of Special Type Engine (AREA)

Abstract

An internal combustion engine has two or more valves 15 per cylinder 12. Each exhaust valve 15 may be individually controlled, e.g. by electromagnetic actuators 19, so that one or more of the exhaust valves 15 remain closed for a predetermined period following cold starting of the engine. This ensures that exhaust gases come into contact with the minimum amount of surface area of the exhaust system 21 before reaching a catalytic converter 22 so that they retain as much of their energy as possible. This results in a higher exhaust gas temperature which in turn reduces the time for the catalytic converter 22 to reach operating temperature. Once the predetermined period has expired the disabled exhaust valve 15 is activated so that both or all valves operate together. The predetermined period may be a fixed time period, a fixed number of engine revolutions or a period set by a sensor indicative of when the catalyst has reached operating temperature.

Description

2341892 - 1 Internal Combustion Engine The invention relates to
piston-type internal combustion engines of the kind in which there are two or more exhaust valves per cylinder. In general, the use of two or more exhaust valves improves the gas flow and enables the use of smaller valves to allow higher operating speeds because 5 of reduced inertias.
The use of one exhaust valve per cylinder is an advantage in the period immediately following a cold start because less heat is absorbed by the single exhaust valve and there is less surface area in the exhaust port. A catalyst situated in the exhaust system downstream of the exhaust port then receives gas at a higher temperature and catalyst light-off can be achieved in a shorter period.
It is an object of this invention to provide an internal combustion engine having two or more exhaust valves per cylinder and which has the advantages of an engine having a single exhaust valve per cylinder.
According to one aspect of the invention there is provided a piston-type internal combustion engine including two or more exhaust valves operative to control the egress of gases from a combustion chamber and exhaust valve operating means for operating the exhaust valves, said valve operating means being arranged so that at least one or some of the exhaust valves remain closed for a predetermined period following a cold start. Also, according to another aspect of the invention there is provided a method of controlling a piston-type combustion engine including two or more exhaust valves operative to control the egress of gases from a combustion chamber and exhaust valve operating means for operating the exhaust valves, the method comprising keeping at least one or some of the exhaust valves closed for a predetermined period following a cold start.
Conveniently, the predetermined period is a fixed time. However, where a variety of operating conditions are encountered, the predetermined period may be set by a fixed number of engine revolutions or by a sensor indicative of catalyst light-off in a catalyst downstream of the exhaust valve.
The invention will now be described by way of example and with reference to the accompanying drawings, of which:- Fig. 1 is a diagrammatic section of part of an internal combustion engine according to the invention together with an exhaust system and Fig.2 is a part section on the line II-II in Fig. 1.
An internal combustion engine includes a piston 11 operating in a cylinder 12. A pair of inlet valves 13 control the flow of air and fuel (gasoline) from an inlet port 14. Similarly, a pair of exhaust valves 15 control the flow of exhaust gases to an exhaust port 16. The exhaust port 16 is common to both exhaust valves 15 and comprises two branch portions 16A and 16B, one for each exhaust valve. The branch portions 16A and 16B are separated by a dividing wall 17 which is part of the cylinder head 18. 5 The valves are operated electromagnetically by individual actuator units 19.
The exhaust port 16 is connected by an exhaust pipe 21 to a catalytic converter 22. The electromagnetic actuators 19 are controlled individually by an electronic control unit (ECT3) 23. Conveniently this is part of an engine management system which under cold start conditions disables the actuator 19 of one of the exhaust valves 15 so that for a predetermined period following the cold start the one exhaust valve remains closed. During this period the amount of heat absorbed by the closed exhaust valve is very much less than if this valve is operated normally. Also, since the exhaust gas flows from one exhaust valve 15 through the individual exhaust port branch portion 16A there is less wall area to heat up compared with the areas of both exhaust port branch portions 16A and 16B. As a result the temperature of the exhaust gas entering the catalytic converter 22 is higher and the catalyst and light-off quicker.
The predetermined period of exhaust valve disablement is conveniently measured as a fixed time from initial engine firing, e.g. 40 seconds. However, engine operating conditions can differ considerably. For example, the engine may be fitted to a motor vehicle which is started from cold and the vehicle driven slowly or the engine merely idled. On the other hand, the same engine may be started from cold and the vehicle immediately driven at high speeds. Hence it is also convenient to count the number of engine revolutions or firing cycles to set the predetermined period. Similarly, if means are available for sensing or inferring catalyst light-off, this can be used to control the end of the predetermined period. Both these methods allow normal operation of both exhaust valve as soon as possible after a cold start sa that the effect on normal engine operation is minimal.
The invention can be applied in any situation where individual control of the exhaust valves is available, e.g. where electrohydraulic control is used (as illustrated by DE 197 16 042 C) or mechanical disabling is used (as shown in US 4,336,775 or US 4,615,307). Also, variable timing/lift devices such as described in DE 195 16 638 A or DE 195 32 334 A may be adapted and modified to completely eliminate the lift of one exhaust valve for each cylinder.

Claims (10)

-5CIAIMS
1. A piston-type internal combustion engine including two or more exhaust valves operative to control the egress of gases from a combustion chamber and exhaust valve operating means for operating the exhaust valves, said valve operating means being arranged so that at least one or some of the exhaust valves remain closed for a predetermined period following a cold start.
2. An engine according to Claim 1 wherein the predetermined period is a fixed time.
3. An engine according to Claim 1 wherein the predetermined period is set by a fixed number of engine revolutions.
4. An engine according to Claim 1 wherein the predetermined period is set by a sensor indicative of catalyst light-off in a catalyst downstream of the exhaust valve.
5. A method of controlling a piston-type combustion engine including two or more exhaust valves operative to control the egress of gases from a combustion chamber and exhaust valve operating means for operating the exhaust valves, the method comprising keeping at least one or some of the exhaust valves closed for a predetermined period following a cold start.
6. A method according to Claim 5 wherein the predetermined period is a fixed time.
7. A method according to Claim 5 wherein the predetermined period is set by a fixed number of engine revolutions.
8. A method according to Claim 5 wherein the predetermined period is set by a sensor indicative of catalyst light-off in a catalyst downstream of the exhaust valve.
9. A piston-type internal combustion engine substantially as described herein with reference to the accompanying drawing.
10. A method of controlling a piston-type combustion engine substantially as described herein with reference- to the accompanying drawing.
GB9820598A 1998-09-23 1998-09-23 Controlling exhaust valves of an I.C. engine to reduce time for catalytic converter light-off Withdrawn GB2341892A (en)

Priority Applications (1)

Application Number Priority Date Filing Date Title
GB9820598A GB2341892A (en) 1998-09-23 1998-09-23 Controlling exhaust valves of an I.C. engine to reduce time for catalytic converter light-off

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
GB9820598A GB2341892A (en) 1998-09-23 1998-09-23 Controlling exhaust valves of an I.C. engine to reduce time for catalytic converter light-off

Publications (2)

Publication Number Publication Date
GB9820598D0 GB9820598D0 (en) 1998-11-11
GB2341892A true GB2341892A (en) 2000-03-29

Family

ID=10839247

Family Applications (1)

Application Number Title Priority Date Filing Date
GB9820598A Withdrawn GB2341892A (en) 1998-09-23 1998-09-23 Controlling exhaust valves of an I.C. engine to reduce time for catalytic converter light-off

Country Status (1)

Country Link
GB (1) GB2341892A (en)

Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
GB2112456A (en) * 1981-12-03 1983-07-20 Honda Motor Co Ltd Intake or exhaust valve disabling system for an i c engine
US5655362A (en) * 1993-09-24 1997-08-12 Honda Giken Kogyo Kabushiki Kaisha Exhaust emission control system in engine
EP0826870A2 (en) * 1996-08-28 1998-03-04 Unisia Jecs Corporation Apparatus for controlling timings of exhaust valves and method thereof

Patent Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
GB2112456A (en) * 1981-12-03 1983-07-20 Honda Motor Co Ltd Intake or exhaust valve disabling system for an i c engine
US5655362A (en) * 1993-09-24 1997-08-12 Honda Giken Kogyo Kabushiki Kaisha Exhaust emission control system in engine
EP0826870A2 (en) * 1996-08-28 1998-03-04 Unisia Jecs Corporation Apparatus for controlling timings of exhaust valves and method thereof

Also Published As

Publication number Publication date
GB9820598D0 (en) 1998-11-11

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WAP Application withdrawn, taken to be withdrawn or refused ** after publication under section 16(1)