GB2402969A - I.c. engine intake port for reverse tumble - Google Patents
I.c. engine intake port for reverse tumble Download PDFInfo
- Publication number
- GB2402969A GB2402969A GB0314909A GB0314909A GB2402969A GB 2402969 A GB2402969 A GB 2402969A GB 0314909 A GB0314909 A GB 0314909A GB 0314909 A GB0314909 A GB 0314909A GB 2402969 A GB2402969 A GB 2402969A
- Authority
- GB
- United Kingdom
- Prior art keywords
- bowl
- port
- flow
- towards
- floor
- 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
- 230000000630 rising effect Effects 0.000 claims abstract description 19
- 238000002485 combustion reaction Methods 0.000 claims description 35
- 238000005192 partition Methods 0.000 claims description 3
- 238000000926 separation method Methods 0.000 claims description 3
- 230000001939 inductive effect Effects 0.000 claims description 2
- 230000001737 promoting effect Effects 0.000 description 3
- 230000002000 scavenging effect Effects 0.000 description 3
- 239000000203 mixture Substances 0.000 description 2
- 238000013517 stratification Methods 0.000 description 2
- 230000006835 compression Effects 0.000 description 1
- 238000007906 compression Methods 0.000 description 1
- 239000000446 fuel Substances 0.000 description 1
- 238000002955 isolation Methods 0.000 description 1
- 238000009736 wetting Methods 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
- F02B31/04—Modifying induction systems for imparting a rotation to the charge in the cylinder by means within the induction channel, e.g. deflectors
-
- 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
-
- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F02—COMBUSTION ENGINES; HOT-GAS OR COMBUSTION-PRODUCT ENGINE PLANTS
- F02F—CYLINDERS, PISTONS OR CASINGS, FOR COMBUSTION ENGINES; ARRANGEMENTS OF SEALINGS IN COMBUSTION ENGINES
- F02F1/00—Cylinders; Cylinder heads
- F02F1/24—Cylinder heads
- F02F1/42—Shape or arrangement of intake or exhaust channels in cylinder heads
-
- 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)
- Combustion Methods Of Internal-Combustion Engines (AREA)
Abstract
The intake port has a flow passage 10 connected to a bowl 12 of the port (ie the space in the port above the poppet valve 14) such that (a) the port flow passage has a rising ramp 20 on the floor of the port immediately before the passage enters the bowl 12 of the port in order to form a flow nozzle having a throat turning the flow upwards towards the roof of the bowl such that the flow cross-section projected forward from the throat towards the opposite wall 22 of the bowl 12 intersects the wall completely without any part of the cross-section overlapping the gap opened by the poppet valve 14 around the edge of the bowl and (b) the said opposite wall 22 of the bowl 12 is curved normally towards (perpendicular to) the edge of the bowl with a curvature sufficient to turn the exit wall boundary at least partially backwards towards the original entering flow direction into the bowl set by the nozzle formed by the rising ramp on the floor of the port. A pivoted flap 220 may serve as the rising ramp when in the position shown in fig.3; for forward tumble, the flap 220 is made parallel to the intake passage 210.
Description
INTAKE PORT FOR REVERSE TITLE
Field of the invention
The present invention relates to an intake port design to produce reverse tumble in the cylinder of an internal combustion engine.
Background of the invention
It is known in an internal combustion engine having intake and exhaust poppet valves operating according to a four-stroke engine cycle to introduce tumble motion within the combustion chamber for promoting mixture turbulence and/or charge stratification during the intake and compression phases of the four-stroke cycle. It is also known in an internal combustion engine having intake and exhaust poppet valves operating according to a two-stroke engine cycle to introduce tumble motion within the combustion chamber for promoting loop scavenging of the cylinder charge during the gas exchange phase of the two- stroke cycle. Tumble is herein defined as the rotation of the cylinder charge in a plane parallel with the longitudinal axis of the engine cylinder.
There are two directions of tumble motion, namely forward tumble and reverse tumble, according to the flow sequence past the walls of the combustion chamber. Forward tumble is herein defined wherein the flow from the intake port entering the combustion chamber is directed predominantly across the roof of the combustion chamber before being deflected by the cylinder wall towards the piston. Reverse tumble is herein defined wherein the flow from the intake port entering the combustion chamber is directed predominantly along the cylinder wall before being deflected by the piston towards the roof of the combustion chamber. - 2 -
In the case of a four stroke engine with poppet valves, either direction of tumble motion is effective for promoting mixture turbulence and/or charge stratification, but other considerations, such as avoiding wetting of the fuel on the cylinder wall, favour the choice of forward tumble in order to reduce exhaust emissions.
In the case of a two-stroke engine with poppet valves, on the other hand, forward tumble is to be avoided because lo of the risk of shortcircuiting of the intake air directly into the exhaust port without scavenging the cylinder contents when the intake and exhaust valves are simultaneously open during the gas exchange phase. It is therefore important to introduce reverse tumble to ensure effective loop scavenging in two-stroke engine applications.
It is known to provide an intake port of the vertical straight port design for producing reverse tumble. In the vertical straight port design, the direction of the port JO flow passage leading towards the poppet valve is substantially parallel with the longitudinal axis of the engine cylinder and is aimed close to the wall of the engine cylinder so that air entering the combustion chamber is directed predominantly along the cylinder wall before being deflected by the piston towards the roof of the combustion chamber. This however makes the intake port stand up relatively high above the engine cylinder, increasing the height of the engine which is undesirable.
Summary of the invention
In order to improve the intake port design for reverse tumble and reduce the increase in engine height, there is provided according to the present invention, an intake port having a flow passage connected to a bowl of the port which is the space in the port above the associated poppet valve leading to the combustion chamber of the engine, - 3 characterized in that the port flow passage has a rising ramp on the floor of the port immediately before the said passage enters the bowl of the port in order to form a flow nozzle having a throat turning the flow upwards towards the roof of the bowl such that the flow cross-section projected forward from the throat towards the opposite wall of the bowl intersects the wall completely without any part of the cross-section overlapping the gap opened by the poppet valve around the edge of the bowl, and further characterized in lo that the said opposite wall of the bowl is curved normally towards (perpendicular to) the edge of the bowl with a curvature sufficient to turn the exit wall boundary at least partially backwards towards the original entering flow direction into the bowl set by the nozzle formed by the rising ramp on the floor of the port.
Preferably, the said rising ramp on the floor of the port is followed by a steep falling step into the bowl for inducing boundary layer separation of the flow immediately after the nozzle thereby projecting the flow towards the opposite wall of the bowl, and the said curvature of the opposite wall of the bowl is sufficient to turn the exit wall boundary by an arc of at least 100 from the original entering flow direction into the bowl set by the nozzle formed by the rising ramp on the floor of the port. Of course any arc of the curvature greater than 90 will produce an exit direction component backwards towards the A original entering flow direction into the bowl.
In a preferred embodiment of the invention, a flap is provided moveable between two positions, a first position defining the said rising ramp on the floor of the port forming a nozzle with a steep falling step behind the nozzle for projecting the flow towards the opposite wall of the bowl having a backwards curvature thereby producing reverse tumble within the combustion chamber, and a second position forming a flow partition parallel with the port flow passage - 4 - for guiding the flow along a direct route towards the gap opened by the poppet valve around the edge of the bowl thereby producing forward tumble within the combustion chamber.
In contrast to the conventional design of the intake port where the port flow passage is directed smoothly towards the gap opened by the poppet valve around the edge of the bowl, and the opposite wall of the bowl is curved lo only as far as guiding the flow in the forward direction for reasons of good volumetric efficiency and directed flow into the combustion chamber in the same direction of the port flow passage, the present invention intentionally prevents the flow from finding a direct route from the port flow passage into the combustion chamber, but instead forces the flow to turn first towards the roof of the bowl and then along the opposite wall of the bowl curved backwards towards the original entering flow direction into the bowl so that the forward momentum is substantially curtailed before the flow enters the combustion chamber thus reversing the induced charge motion within the combustion chamber compared with the conventional design. This allows an intake port design capable of producing reverse tumble without significantly increasing the height of the engine.
It is known to introduce a hump on the floor of an intake port to increase the flow velocity and direct it towards the roof of the port. Indeed this has been proposed as a means to promote forward tumble which is opposite to the objective of the present invention.
It is also known for an intake port to have a backwards curvature at its end wall but without at the same time the rising ramp on the floor of the port followed by a steep falling step as specified in the present invention. In this case, because of the openness of the port, the flow from the port flow passage will naturally find a direct route into - 5 the combustion chamber in the direction of the flow passage with little influence from the end curvature of the port wall and produce forward tumble which is again opposite to the objective of the present invention. s
It is therefore not obvious, whilst the above two features used individually in isolation would produce forward tumble, that by combining the rising ramp on the floor of the port with a backwards curvature in the opposite lo wall of the port that the induced charge motion in the combustion chamber could be reversed, thus producing reverse tumble.
Brief description of the drawing
The invention will now be described further by way of example with reference to the accompanying drawings in which Figure 1 is a schematic view of an intake port of the present invention designed to produce reverse tumble in the combustion chamber, Figure 2 is a similar schematic view of a prior art intake port designed to produce forward tumble in the combustion chamber, and Figure 3 is a schematic view of an intake port similar to Figure 1, showing an alternative embodiment of the invention.
Detailed description of the preferred embodiment
Going first to Figure 2 which shows a conventional intake port having a flow passage 110 connected to a bowl 112 of the port which is the space in the port above the associated poppet valve 114 leading to the combustion chamber 116 of the engine. In the conventional intake port, the floor 120 of the flow passage is substantially straight directing the flow towards the gap opened by the poppet valve 114 around the edge of the bowl 112 as shown by the - 6 - flow arrows. The opposite wall 122 of the bowl 112 is curved only as far as guiding the flow in the forward direction for reasons of good volumetric efficiency and directed flow into the combustion chamber 116 in the same direction of the port flow passage 110. In this way a forward tumble charge motion is produced in the combustion chamber 116 as shown by the flow arrows.
By contrast, in Figure 1 which shows an intake port of lo the present invention, the intake port has a flow passage 10 connected to a bowl 12 of the port which is the space in the port above the associated poppet valve 14 leading to the combustion chamber 16 of the engine. In the intake port, the port flow passage 10 has a rising ramp 20 on the floor of the port immediately before the said passage enters the bowl 12 of the port in order to form a flow nozzle with a steep falling step behind the nozzle, and a throat turning the flow upwards towards the roof of the bowl 12. Because of boundary layer separation induced at the steep falling step behind the nozzle, the flow from the throat will project forwards towards the opposite wall 22 of the bowl 12 and is turned by the wall 22 before reaching the gap opened by the poppet valve 14 around the edge of the bowl 12 as shown by the flow arrows. In addition, the said opposite wall 22 of the bowl 12 is curved normally towards (perpendicular to) the edge of the bowl 12 with a curvature sufficient to turn the exit wall boundary at least partially backwards towards the original entering flow direction into the bowl set by the nozzle formed by the rising ramp 20 on the floor of the port.
In Figure 1, the said curvature of the opposite wall 22 of the bowl 12 is sufficient to turn the exit wall boundary by an arc greater than 100 from the original entering flow direction into the bowl set by the nozzle formed by the rising ramp 20 on the floor of the port. In this way, the flow is prevented from finding a direct route from the port flow passage 10 into the combustion chamber 16, but instead is forced to turn first towards the roof of the bowl 12 and then along the opposite wall 22 of the bowl 12 curved backwards towards the original entering flow direction into the bowl so that the forward momentum is substantially curtailed before the flow enters the combustion chamber 16 thus reversing the induced charge motion within the combustion chamber 16 compared with the conventional design shown in Figure 2. This enables the intake port of Figure 1 lo to produce a reverse tumble charge motion in the combustion chamber 16 as shown by the flow arrows.
An alternative embodiment of the present invention is shown in Figure 3 where a pivoted moveable flap 220 is provided serving as a rising ramp following by a steep falling step when it is moved to a first position as shown forming a nozzle for projecting the flow towards the opposite wall 222 of the bowl 212 having a backwards curvature thus producing reverse tumble within the combustion chamber 216. When forward tumble is required, the flap 220 is moved to a second position (not shown) forming a flow partition parallel with the port flow passage 210 offering the minimum obstruction to the flow and guiding the flow along a direct route towards the gap opened by the poppet valve 214 around the edge of the bowl 212. 8
Claims (4)
1. An intake port for producing reverse tumble having a flow passage connected to a bowl of the port which is the space in the port above the associated poppet valve leading to the combustion chamber of the engine, characterized in that the port flow passage has a rising ramp on the floor of the port immediately before the said passage enters the bowl of the port in order to form a flow nozzle having a throat lo turning the flow upwards towards the roof of the bowl such that the flow cross- section projected forward from the throat towards the opposite wall of the bowl intersects the wall completely without any part of the cross- section overlapping the gap opened by the poppet valve around the edge of the bowl, and further characterized in that the said opposite wall of the bowl is curved normally towards (perpendicular to) the edge of the bowl with a curvature sufficient to turn the exit wall boundary at least partially backwards towards the original entering flow direction into the bowl set by the nozzle formed by the rising ramp on the floor of the port.
2. An intake port as claimed in claim 1, wherein the said rising ramp on the floor of the port is followed by a steep falling step for inducing boundary layer separation of the flow immediately after the nozzle thereby projecting the flow towards the opposite wall of the bowl.
3. An intake port as claimed in claim 1 or 2, wherein a flap is provided moveable between two positions, a first position defining the said rising ramp on the floor of the port forming a nozzle with a steep falling step behind the nozzle for projecting the flow towards the opposite wall of the bowl having a backwards curvature thereby producing reverse tumble within the combustion chamber, and a second position forming a flow partition parallel with the port flow passage for guiding the flow along a direct route _ 9 _ towards the gap opened by the poppet valve around the edge of the bowl thereby producing forward tumble within the combustion chamber.
4. An intake port as claimed in any preceding claim, wherein the said curvature of the opposite wall of the bowl is sufficient to turn the exit wall boundary by an arc of at least 100 from the original entering flow direction into the bowl set by the nozzle formed by the said rising ramp on lo the floor of the port.
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| GBGB0313988.8A GB0313988D0 (en) | 2003-06-17 | 2003-06-17 | Intake port for reverse tumble |
Publications (3)
| Publication Number | Publication Date |
|---|---|
| GB0314909D0 GB0314909D0 (en) | 2003-07-30 |
| GB2402969A true GB2402969A (en) | 2004-12-22 |
| GB2402969B GB2402969B (en) | 2006-05-24 |
Family
ID=27636688
Family Applications (2)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| GBGB0313988.8A Ceased GB0313988D0 (en) | 2003-06-17 | 2003-06-17 | Intake port for reverse tumble |
| GB0314909A Expired - Fee Related GB2402969B (en) | 2003-06-17 | 2003-06-26 | Intake port for reverse tumble |
Family Applications Before (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| GBGB0313988.8A Ceased GB0313988D0 (en) | 2003-06-17 | 2003-06-17 | Intake port for reverse tumble |
Country Status (1)
| Country | Link |
|---|---|
| GB (2) | GB0313988D0 (en) |
Cited By (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| FR2910541A1 (en) * | 2006-12-21 | 2008-06-27 | Renault Sas | Gas intake system for e.g. direct injection petrol engine, has wheel ramp arranged in gas intake conduit at level of concave side and placed near valve seat, where wheel ramp is obtained by molding in sand core mold |
| FR2915236A3 (en) * | 2007-04-20 | 2008-10-24 | Renault Sas | Tumble type variable streamline generating device for e.g. petrol engine of motor vehicle, has seat with projecting part formed of revolution surfaces whose dimensions do not modify discharge of intake flow during high lifting |
| US20180347451A1 (en) * | 2017-06-06 | 2018-12-06 | Dr. Ing. H.C. F. Porsche Aktiengesellschaft | Cylinder head for an internal combustion engine, internal combustion engine, and method for operating an internal combustion engine |
| CN110388274A (en) * | 2018-04-18 | 2019-10-29 | 丰田自动车株式会社 | The cylinder cover of internal combustion engine |
Citations (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPH09242550A (en) * | 1996-03-07 | 1997-09-16 | Nissan Motor Co Ltd | Spark ignition engine of direct cylinder fuel injection type |
| JPH11270342A (en) * | 1998-03-23 | 1999-10-05 | Nissan Motor Co Ltd | Intake controller for cylinder injection type spark-ignition engine |
| JP2003003854A (en) * | 2001-06-20 | 2003-01-08 | Toyota Central Res & Dev Lab Inc | In-cylinder direct injection jump-spark-ignition internal combustion engine and mixture forming method in in- cylinder direct injection jump-spark-ignition internal combustion engine |
-
2003
- 2003-06-17 GB GBGB0313988.8A patent/GB0313988D0/en not_active Ceased
- 2003-06-26 GB GB0314909A patent/GB2402969B/en not_active Expired - Fee Related
Patent Citations (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPH09242550A (en) * | 1996-03-07 | 1997-09-16 | Nissan Motor Co Ltd | Spark ignition engine of direct cylinder fuel injection type |
| JPH11270342A (en) * | 1998-03-23 | 1999-10-05 | Nissan Motor Co Ltd | Intake controller for cylinder injection type spark-ignition engine |
| JP2003003854A (en) * | 2001-06-20 | 2003-01-08 | Toyota Central Res & Dev Lab Inc | In-cylinder direct injection jump-spark-ignition internal combustion engine and mixture forming method in in- cylinder direct injection jump-spark-ignition internal combustion engine |
Cited By (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| FR2910541A1 (en) * | 2006-12-21 | 2008-06-27 | Renault Sas | Gas intake system for e.g. direct injection petrol engine, has wheel ramp arranged in gas intake conduit at level of concave side and placed near valve seat, where wheel ramp is obtained by molding in sand core mold |
| FR2915236A3 (en) * | 2007-04-20 | 2008-10-24 | Renault Sas | Tumble type variable streamline generating device for e.g. petrol engine of motor vehicle, has seat with projecting part formed of revolution surfaces whose dimensions do not modify discharge of intake flow during high lifting |
| US20180347451A1 (en) * | 2017-06-06 | 2018-12-06 | Dr. Ing. H.C. F. Porsche Aktiengesellschaft | Cylinder head for an internal combustion engine, internal combustion engine, and method for operating an internal combustion engine |
| CN110388274A (en) * | 2018-04-18 | 2019-10-29 | 丰田自动车株式会社 | The cylinder cover of internal combustion engine |
| CN110388274B (en) * | 2018-04-18 | 2021-12-14 | 丰田自动车株式会社 | Cylinder head of internal combustion engine |
Also Published As
| Publication number | Publication date |
|---|---|
| GB0313988D0 (en) | 2003-07-23 |
| GB2402969B (en) | 2006-05-24 |
| GB0314909D0 (en) | 2003-07-30 |
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Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| PCNP | Patent ceased through non-payment of renewal fee |
Effective date: 20070626 |