GB2334303A - An ic engine intake duct having a curved baffle plate - Google Patents
An ic engine intake duct having a curved baffle plate Download PDFInfo
- Publication number
- GB2334303A GB2334303A GB9802766A GB9802766A GB2334303A GB 2334303 A GB2334303 A GB 2334303A GB 9802766 A GB9802766 A GB 9802766A GB 9802766 A GB9802766 A GB 9802766A GB 2334303 A GB2334303 A GB 2334303A
- Authority
- GB
- United Kingdom
- Prior art keywords
- intake
- baffle plate
- charge
- duct
- engine
- 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- Withdrawn
Links
- 239000000446 fuel Substances 0.000 claims abstract description 31
- 238000002485 combustion reaction Methods 0.000 claims description 22
- TVMXDCGIABBOFY-UHFFFAOYSA-N octane Chemical compound CCCCCCCC TVMXDCGIABBOFY-UHFFFAOYSA-N 0.000 claims description 16
- 239000007788 liquid Substances 0.000 claims description 7
- 238000011144 upstream manufacturing Methods 0.000 claims description 2
- 238000013517 stratification Methods 0.000 abstract description 6
- 239000007789 gas Substances 0.000 description 6
- 239000000203 mixture Substances 0.000 description 3
- 230000006835 compression Effects 0.000 description 2
- 238000007906 compression Methods 0.000 description 2
- 239000012141 concentrate Substances 0.000 description 1
- 238000012986 modification Methods 0.000 description 1
- 230000004048 modification Effects 0.000 description 1
Classifications
-
- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F02—COMBUSTION ENGINES; HOT-GAS OR COMBUSTION-PRODUCT ENGINE PLANTS
- F02B—INTERNAL-COMBUSTION PISTON ENGINES; COMBUSTION ENGINES IN GENERAL
- F02B31/00—Modifying induction systems for imparting a rotation to the charge in the cylinder
- F02B31/08—Modifying induction systems for imparting a rotation to the charge in the cylinder having multiple air inlets
- F02B31/085—Modifying induction systems for imparting a rotation to the charge in the cylinder having multiple air inlets having two inlet valves
-
- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F02—COMBUSTION ENGINES; HOT-GAS OR COMBUSTION-PRODUCT ENGINE PLANTS
- F02B—INTERNAL-COMBUSTION PISTON ENGINES; COMBUSTION ENGINES IN GENERAL
- F02B31/00—Modifying induction systems for imparting a rotation to the charge in the cylinder
- F02B31/04—Modifying induction systems for imparting a rotation to the charge in the cylinder by means within the induction channel, e.g. deflectors
- F02B31/06—Movable means, e.g. butterfly valves
-
- Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
- Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
- Y02T—CLIMATE CHANGE MITIGATION TECHNOLOGIES RELATED TO TRANSPORTATION
- Y02T10/00—Road transport of goods or passengers
- Y02T10/10—Internal combustion engine [ICE] based vehicles
- Y02T10/12—Improving ICE efficiencies
Landscapes
- Engineering & Computer Science (AREA)
- Chemical & Material Sciences (AREA)
- Combustion & Propulsion (AREA)
- Mechanical Engineering (AREA)
- General Engineering & Computer Science (AREA)
- Cylinder Crankcases Of Internal Combustion Engines (AREA)
Abstract
An intake system for an ic engine comprises an intake duct 20 and a curved rotatable baffle plate 22, 24 mounted on a spindle 30 and rotatable between a first position, for low load operation, where part 24 of the plate obstructs a first side of the duct 20 while directing air to a second side of the duct 20 and a second position, for high load operation, where part 22 obstructs the second side of duct 20 while directing air to the first side of duct 20. Preferably when the baffle is in the high load position part 22 of the baffle only partly obstructs the second side of the duct 20 thus allowing some air to pass through the second side of the duct 20. The baffle induces swirl within the duct and is particularly effective when combined with a fuel system, that separates fuel into different fractions, in providing charge stratification.
Description
INTAKE SYSTEM FOR AN INTERNAL COMBUSTION ENGINE
Field of the invention
The present invention relates to an intake system for an internal combustion engine having at least one cylinder and at least one intake valve through which intake charge can be drawn into the cylinder, the intake system comprising an intake duct and a movable baffle plate arranged to restrict the flow along the intake duct, the baffle plate being mounted on a spindle and rotatable between a first position for low load operation and a second position for high load operation.
Background of the invention
It is already known to place a baffle plate in an intake duct of an engine downstream of the main butterfly throttle for the purpose of swirl control. The/baffle plate does not affect the engine load nor determine the rate of air flow into the combustion chamber but serves only to affect the distribution of the charge to enhance mixing or charge stratification, as the case may be.
In co-pending Patent Application No. 9801753.6, the
Applicants have proposed a baffle plate that is pivotable about a spindle. The plate is flat over one half of the area of the intake duct but its remainder is curved away from the axis of the spindle. When the spindle is turned to one end position, the plate lies edge on to the gas flow in the intake duct and presents substantially no obstruction over the cross-section of the intake duct. When the spindle is turned through 90" to its other end position, the flat part of the baffle plate obstructs one side of the intake duct while the curved part acts as a convergent flow guide directing a smooth flow of gas into a restricted flow crosssection on the opposite side of the intake duct. In this way, when the intake duct is not obstructed, i.e. during high load operation, the gases enter the combustion chamber from all sides of the intake duct and create a homogeneously mixed charge. On the other hand, when the intake duct is partly obstructed by the baffle plate, i.e. during low load operation, the intake charge enters only from one side of the intake duct and by suitable design of the intake duct and the combustion chamber can be caused to create a radially stratified swirling charge in the combustion chamber.
Object of the invention
The present invention seeks to provide a modification of that in copending Patent Application No. 9801753.6 that achieves a swirling charge in the combustion chamber both during low load operation and high load operation and permits the swirl pattern to be varied to achieve robust ignition during low load operation and increased tolerance to knock during high load operation.
Summary of the invention
According to the present invention, there is provided an intake system for an internal combustion engine having at least one cylinder and at least one intake valve through which intake charge can be drawn into the cylinder, the intake system comprising an intake duct and a movable baffle plate arranged to restrict the flow along the intake duct, the baffle plate being mounted on a spindle and rotatable between a first position for low load operation and a second position for high load operation, wherein at least one portion of the baffle plate is bent about an axis normal to the direction of gas flow in the intake system and the plate is mounted on a spindle parallel to the said axis for pivotal movement between two end positions, the plate, when in one end position, obstructing a first side of the intake duct and guiding the air flow towards the second side of the intake duct and, when in the other end position, obstructing the second side of intake duct and guiding the air flow towards the first side of the intake duct.
In a preferred embodiment of the invention, the baffle plate is curved at one end and the position of the spindle is such that the flow cross-sections through which the charge is guided in the different end positions of the spindle are different in area from one another, such that during low load operation the charge is admitted into the combustion chamber with a higher velocity through a smaller area and during high load operation the charge is admitted into the combustion chamber with a lower velocity through a larger area.
When an intake system of the present invention is fitted to an engine in which each cylinder has two intake valves supplied respectively by a swirl port ant a flow port, the two ports being connected to a common intake duct, the baffle plate is preferably arranged such that in the first position the smaller flow cross-section is directed towards the swirl port and in the second position the larger flow cross-section is directed towards the flow port.
When the invention is applied to an engine running on gasoline fuel, the fuel to be introduced to the engine may first be separated in a fuel fractioning system into a lighter vapour fraction and a heavier liquid fraction, the former having a lower octane number and the latter a higher octane number than the average octane number of the original fuel, and the two fuel fractions may be introduced into the intake duct separately in different regions relative to the baffle plate so that they may be drawn separately into the engine cylinder to occupy different regions in the trapped charge during combustion.
At low engine load with the baffle plate in the first position, the vapour fuel fraction may be introduced into the high velocity air stream passing through the baffle plate while the liquid fuel fraction may be introduced into the low velocity region behind the baffle plate. This would result in charge stratification with the lower octane fuel fraction swirling predominantly in the periphery of the cylinder and the higher octane fuel fraction residing predominantly near the centre of the cylinder.
At high engine load with the baffle plate in the second position, the high velocity air stream is transferred to the other side of the intake duct changing the speed and direction of swirl in the combustion chamber. Moreover, with the fuel fractions being introduced in the same respective directions as before, the liquid fuel fraction will join the high velocity air stream at the other side of the intake duct while the vapour fuel fraction will enter the low velocity region behind the baffle plate! This would result in charge stratification with the higher octane fuel fraction swirling predominantly in the periphery of the cylinder and the lower octane fuel fraction residing predominantly near the centre of the cylinder.
Thus for each position of the baffle plate, a different stratification of the fuel fractions is achieved which is advantageous for the respective engine operating conditions at low and high loads, the first position extending the lean burn capability of the engine and achieving controlled autoignition of the lean mixture, the second position extending the knock tolerance of the engine, allowing the engine to be pressure charged and its compression ratio to be increased.
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 representation of an engine
fitted with an intake system of the invention, the
drawing showing a single cylinder of the engine having
two intake valves and two exhaust valves, the baffle
plate being shown in the low load position,
Figure la is an end view looking towards the intake
valves from a common intake duct, and
Figures 2 and 2a show the same engine with the
baffle plate in the high load position, the Figures
corresponding respectively to Figure 1 and Figure la.
Detailed description of the drawings
The drawings show a cylinder 10 having twovintake valves 12, 14, two exhaust valves 16 and a spark plug 18.
The intake valves 12, 14 are arranged at the grids of a siamesed intake port 20. At the entrance to the siamesed intake port 20 from its supply duct there is arranged a baffle plate 22, 24 that is rotatable about a spindle 30 of which the axis is normal to the plane of the drawings. The part 24 of the baffle plate that lies to one side of the spindle 30 is flat while the part 22 that lies on the other side of the spindle 30 is curved with its axis of curvature parallel to the spindle axis.
The spindle 30 has two end positions shown in Figures 1 and 2 respectively. In the end position shown in Figure 1 the flat part 24 of the baffle plate obstructs one side of the intake port 20 while the other part 22 guides the intake charge towards the other side of the intake port. This is also clearly seen from Figure la which shows that the intake charge can only flow through a restricted flow passage 26a towards the intake valve 12. As will be described below, this position is best for low load operation. In the other end position of the spindle 30, as shown in Figure 2, the flat part 24 of the baffle plate les parallel to the direction of gas flow and leaves an unobstructed flow passage 26b for the intake charge flowing towards the intake valve 14. On the zither hand, the curved part 22 of the baffle plate at least partially obstructs the other side of the intake port but guides the flow towards the open passage. This position is best for high load operation.
The fuelling system to the engine, which is not shown in the drawings, may be conventional but is preferably one that first separates the fuel into a lower and a higher octane fraction. In this case the lower octane fraction is mixed with the intake air charge upstream of the baffle plate and essentially enters the combustion chamber as a vapour. The higher octane fraction, on the other hand, is preferably injected as liquid droplets downstream of the baffle plate and is directed towards the intake valve 14.
The intake valve 12 is positioned in a swirl port designed to produce clockwise swirl (as viewed) in the engine cylinder 10. The baffle plate when in the low load position further enhances the swirl by guiding the intake charge towards the side of the intake port in the same direction as the swirl port and increasing the charge velocity. In this way, the vapour fuel fraction will enter the cylinder through the intake valve 12 and swirl predominantly in the periphery of the cylinder. At the same time, the liquid fuel fraction will enter the cylinder through the intake valve 14 and will lie predominantly near the centre of the cylinder. With such charge stratification, the region of the charge in the vicinity of the spark plug has a higher fuel concentration and will be readily ignitable even when the overall mixture is lean. Once the flame has been ignited, the increased swirl in the lean mixture charge will burn rapidly and the increased temperature and pressure can cause autoignition of the lower octane fuel fraction in the remainder of the combustion chamber. The intake system in this way improves the lean burn capability of the engine and encourages controlled autoignition which is known to produce very low NOx emissions.
The intake valve 14 is positioned in a flow port designed to provide high flow into the engine cylinder. The baffle plate when in the high load position changes the flow pattern and directs the intake charge towards the intake valve 14. Under high load operation, the fuel charge is stoichiometric and ignitability does not present a problem.
On the other hand, the risk of engine knock increases which limits the maximum power of the engine.
With the intake system of the invention, the intake charge entering through the intake valve 14 andzcarrying with it the liquid fuel fraction will swirl anticlockwise as viewed and will concentrate the higher octane fuel fraction in the periphery of the combustion chamber. As the end-gas region during combustion normally lies in the periphery of the combustion chamber, the tendency to autoignite under high load is reduced allowing the engine to be pressure charged and its compression ratio to be increased.
Claims (6)
1. An intake system for an internal combustion engine having at least one cylinder and at least one intake valve through which intake charge can be drawn into the cylinder, the intake system comprising an intake duct and a movable baffle plate arranged to restrict the flow along the intake duct, the baffle plate being mounted on a spindle and rotatable between a first position for low load operation and a second position for high load operation, wherein at least one portion of the baffle plate is bent about an axis normal to the direction of gas flow in the intake system and the plate is mounted on a spindle parallel to the said axis for pivotal movement between two end positions, the plate, when in one end position, obstructing a first side of the intake duct and guiding the air flow towards the second side of the intake duct and, when in the other end position, obstructing the second side of intake duct and guiding the air flow towards the first side of the intake dart.
2. An intake system as claimed in claim 1, wherein the baffle plate is curved at one end and the position of the spindle is such that the flow cross-sections through which the charge is guided in the different end positions of the spindle are different in area from one another, such that during low load operation the charge is admitted into the combustion chamber with a higher velocity through a smaller area and during high load operation the charge is admitted into the combustion chamber with a lower velocity through a larger area.
3. An intake system as claimed in claim 1 or 2, in combination with an engine in which each cylinder has two intake valves supplied respectively by a swirl port and a flow port, the two ports being connected to a common intake duct, wherein the baffle plate is arranged such that in the first position the smaller flow cross-section is directed towards the swirl port and in the second position the larger flow cross-section is directed towards the flow port.
4. An intake system as claimed in any preceding claim in combination with an engine that burns gasoline fuel having a fuel fractioning system for first separating the fuel to be introduced to the engine into a lighter, lower octane, vapour fraction and a heavier, higher octane, liquid fraction, wherein means are provided for introducing the two fuel fractions separately into different regions of the intake duct relative to the baffle plate so that they may be drawn into the engine cylinder to occupy different regions in the trapped charge during combustion.
5. An intake system as claimed in claim 4, comprising means for introducing the lower octane fraction of the fuel into the intake charge upstream of the baffle plate and the higher octane fraction of the fuel downstream of the baffle plate and towards the side of the intake port through which the intake charge flows during high load operation.
6. An intake system for an internal combustion engine constructed, arranged and adapted to operate substantially as hereinbefore described with reference to and as illustrated in the accompanying drawings.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| GB9802766A GB2334303A (en) | 1998-02-11 | 1998-02-11 | An ic engine intake duct having a curved baffle plate |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| GB9802766A GB2334303A (en) | 1998-02-11 | 1998-02-11 | An ic engine intake duct having a curved baffle plate |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| GB9802766D0 GB9802766D0 (en) | 1998-04-08 |
| GB2334303A true GB2334303A (en) | 1999-08-18 |
Family
ID=10826726
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| GB9802766A Withdrawn GB2334303A (en) | 1998-02-11 | 1998-02-11 | An ic engine intake duct having a curved baffle plate |
Country Status (1)
| Country | Link |
|---|---|
| GB (1) | GB2334303A (en) |
Cited By (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| LU90598B1 (en) * | 2000-06-14 | 2001-12-17 | Delphi Tech Inc | Internal combustion engine with swirl control means |
| FR2819014A1 (en) * | 2000-12-28 | 2002-07-05 | Renault | GAS INTAKE SYSTEM IN A CYLINDER OF A COMBUSTION ENGINE |
| FR2879248A1 (en) * | 2004-12-13 | 2006-06-16 | Renault Sas | Gas intake duct stopper for internal combustion engine of motor vehicle, has intake device with movable unit movable between two end positions in which duct is opened and closed, where unit is fixed in cylinder head |
| AT512110A1 (en) * | 2011-10-05 | 2013-05-15 | Mahle Koenig Kommanditgesellschaft Gmbh & Co Kg | ENGINE CYLINDER |
Citations (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| GB835098A (en) * | 1956-12-12 | 1960-05-18 | Augsburg I Nurnberg A G Maschf | Improvements in and relating to internal combustion engines |
| GB1572641A (en) * | 1976-03-05 | 1980-07-30 | Nissan Motor | Internal combustion engine with intake arrangement to produce swirl in combustion chamber |
| US4850317A (en) * | 1986-04-02 | 1989-07-25 | Mitsubishi Jidosha Kogyo Kabushiki Kaisha | Intake port device |
| US5640941A (en) * | 1995-12-04 | 1997-06-24 | Ford Motor Company | Internal combustion engine with stratified charge and tumble motion |
-
1998
- 1998-02-11 GB GB9802766A patent/GB2334303A/en not_active Withdrawn
Patent Citations (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| GB835098A (en) * | 1956-12-12 | 1960-05-18 | Augsburg I Nurnberg A G Maschf | Improvements in and relating to internal combustion engines |
| GB1572641A (en) * | 1976-03-05 | 1980-07-30 | Nissan Motor | Internal combustion engine with intake arrangement to produce swirl in combustion chamber |
| US4850317A (en) * | 1986-04-02 | 1989-07-25 | Mitsubishi Jidosha Kogyo Kabushiki Kaisha | Intake port device |
| US5640941A (en) * | 1995-12-04 | 1997-06-24 | Ford Motor Company | Internal combustion engine with stratified charge and tumble motion |
Cited By (6)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| LU90598B1 (en) * | 2000-06-14 | 2001-12-17 | Delphi Tech Inc | Internal combustion engine with swirl control means |
| FR2819014A1 (en) * | 2000-12-28 | 2002-07-05 | Renault | GAS INTAKE SYSTEM IN A CYLINDER OF A COMBUSTION ENGINE |
| EP1219798A3 (en) * | 2000-12-28 | 2002-09-11 | Renault s.a.s. | Gas intake device for an internal combustion engine |
| FR2879248A1 (en) * | 2004-12-13 | 2006-06-16 | Renault Sas | Gas intake duct stopper for internal combustion engine of motor vehicle, has intake device with movable unit movable between two end positions in which duct is opened and closed, where unit is fixed in cylinder head |
| AT512110A1 (en) * | 2011-10-05 | 2013-05-15 | Mahle Koenig Kommanditgesellschaft Gmbh & Co Kg | ENGINE CYLINDER |
| AT512110B1 (en) * | 2011-10-05 | 2013-06-15 | Mahle Koenig Kommanditgesellschaft Gmbh & Co Kg | ENGINE CYLINDER |
Also Published As
| Publication number | Publication date |
|---|---|
| GB9802766D0 (en) | 1998-04-08 |
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Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| WAP | Application withdrawn, taken to be withdrawn or refused ** after publication under section 16(1) |