GB2443690A - Retractable cam system for an 8-stroke and 4-stroke cycle change engine - Google Patents
Retractable cam system for an 8-stroke and 4-stroke cycle change engine Download PDFInfo
- Publication number
- GB2443690A GB2443690A GB0622278A GB0622278A GB2443690A GB 2443690 A GB2443690 A GB 2443690A GB 0622278 A GB0622278 A GB 0622278A GB 0622278 A GB0622278 A GB 0622278A GB 2443690 A GB2443690 A GB 2443690A
- Authority
- GB
- United Kingdom
- Prior art keywords
- stroke
- retractable
- cam
- camshaft
- cams
- 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
- 239000000446 fuel Substances 0.000 claims abstract description 27
- 230000006698 induction Effects 0.000 claims abstract description 25
- 238000002485 combustion reaction Methods 0.000 claims description 4
- 238000003801 milling Methods 0.000 claims description 3
- 238000002347 injection Methods 0.000 claims 1
- 239000007924 injection Substances 0.000 claims 1
- 238000000034 method Methods 0.000 description 1
- 230000000284 resting effect Effects 0.000 description 1
- 125000006850 spacer group Chemical group 0.000 description 1
Classifications
-
- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F01—MACHINES OR ENGINES IN GENERAL; ENGINE PLANTS IN GENERAL; STEAM ENGINES
- F01L—CYCLICALLY OPERATING VALVES FOR MACHINES OR ENGINES
- F01L1/00—Valve-gear or valve arrangements, e.g. lift-valve gear
- F01L1/36—Valve-gear or valve arrangements, e.g. lift-valve gear peculiar to machines or engines of specific type other than four-stroke cycle
-
- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F01—MACHINES OR ENGINES IN GENERAL; ENGINE PLANTS IN GENERAL; STEAM ENGINES
- F01L—CYCLICALLY OPERATING VALVES FOR MACHINES OR ENGINES
- F01L13/00—Modifications of valve-gear to facilitate reversing, braking, starting, changing compression ratio, or other specific operations
- F01L13/0005—Deactivating valves
-
- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F01—MACHINES OR ENGINES IN GENERAL; ENGINE PLANTS IN GENERAL; STEAM ENGINES
- F01L—CYCLICALLY OPERATING VALVES FOR MACHINES OR ENGINES
- F01L13/00—Modifications of valve-gear to facilitate reversing, braking, starting, changing compression ratio, or other specific operations
- F01L13/0015—Modifications of valve-gear to facilitate reversing, braking, starting, changing compression ratio, or other specific operations for optimising engine performances by modifying valve lift according to various working parameters, e.g. rotational speed, load, torque
- F01L13/0036—Modifications of valve-gear to facilitate reversing, braking, starting, changing compression ratio, or other specific operations for optimising engine performances by modifying valve lift according to various working parameters, e.g. rotational speed, load, torque the valves being driven by two or more cams with different shape, size or timing or a single cam profiled in axial and radial direction
-
- 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
- F02B69/00—Internal-combustion engines convertible into other combustion-engine type, not provided for in F02B11/00; Internal-combustion engines of different types characterised by constructions facilitating use of same main engine-parts in different types
- F02B69/06—Internal-combustion engines convertible into other combustion-engine type, not provided for in F02B11/00; Internal-combustion engines of different types characterised by constructions facilitating use of same main engine-parts in different types for different cycles, e.g. convertible from two-stroke to four stroke
-
- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F01—MACHINES OR ENGINES IN GENERAL; ENGINE PLANTS IN GENERAL; STEAM ENGINES
- F01L—CYCLICALLY OPERATING VALVES FOR MACHINES OR ENGINES
- F01L1/00—Valve-gear or valve arrangements, e.g. lift-valve gear
- F01L1/02—Valve drive
- F01L1/04—Valve drive by means of cams, camshafts, cam discs, eccentrics or the like
- F01L1/047—Camshafts
- F01L2001/0471—Assembled camshafts
- F01L2001/0473—Composite camshafts, e.g. with cams or cam sleeve being able to move relative to the inner camshaft or a cam adjusting rod
-
- 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
- F02B75/00—Other engines
- F02B75/02—Engines characterised by their cycles, e.g. six-stroke
- F02B2075/022—Engines characterised by their cycles, e.g. six-stroke having less than six strokes per cycle
- F02B2075/027—Engines characterised by their cycles, e.g. six-stroke having less than six strokes per cycle four
-
- 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
- F02B75/00—Other engines
- F02B75/02—Engines characterised by their cycles, e.g. six-stroke
- F02B75/021—Engines characterised by their cycles, e.g. six-stroke having six or more strokes per cycle
Landscapes
- Engineering & Computer Science (AREA)
- Mechanical Engineering (AREA)
- General Engineering & Computer Science (AREA)
- Chemical & Material Sciences (AREA)
- Combustion & Propulsion (AREA)
- Output Control And Ontrol Of Special Type Engine (AREA)
- Valve Device For Special Equipments (AREA)
Abstract
An 8 Stroke and 4 stroke cycle change engine where the inlet camshaft has retractable and extendable cams 5, 6 so that all inlet valves open for all induction strokes and maximum power when the retractable cams are extended. For lower power the retractable cams are retracted within the camshaft leaving two fixed cams 10, 11 on opposite sides of a camshaft driven at one-quarter crankshaft speed which then open separate fuel/air and 'air only' inlet valves for alternate induction strokes. This is the fuel efficient alternate 'air only' induction sequence, the 8 Stroke or Blackburn Cycle. The same mechanism can be used to vary the opening of an inlet valve to control the power in place of a throttle. The cams 5, 6 may be actuated by sliding wedges 4.
Description
RETRACTABLE CAM
This invention relates to Internal Combustion Engines My previous patent EP 0578637 and related patents described 8 Stroke and 4 Stroke cycle change engines or the Blackburn Cycle. A main feature was the use of alternate air only' inductions in each cylinder, usually with separate alternate acting inlet valves. One inlet valve was used for alternate fuel/air inductions and a second inlet valve used for the alternate air only' inductions when less than half load was needed.
However, when high power was needed the fuel injector for the air only' inlet was switched on to give combustion on every 4 stroke cycle, but only one of the two inlet valves opened for any one induction stroke. This reduced the fuel/air entering the cylinder and reduced the maximum power. This invention allows all inlet valves to open for maximum power while changing to the alternate inlet valve opening sequence for fuel efficient cruising and idling.
DESCRIPTION
001 According to the present invention there is provided an 8 stroke and 4 stroke cycle change engine where at least one inlet cam operable with at least one inlet valve in an engine cylinder is retractable within a camshaft causing an inlet valve to remain closed for an induction stroke with provision for the cam to extend to open an inlet valve for other induction strokes.
002 Usually two retractable cams are located on opposite sides of the camshaft, operable with two or more inlet valves for each cylinder, so that all inlet valves open for adjacent induction strokes when the cams are extended but the inlet valves open for alternate induction strokes when the cams are retracted using fixed cams which are also on opposite sides of a camshaft driven at % crankshaft speed.
003 The retractable cam form itself opens and closes an inlet valve in approximately degrees of camshaft rotation when extended, and the cam form is concave at the point where the retractable can-i starts to open and ends closing an inlet valve.
004 When there are two retractable cams Ofl Opposite sides of a camshaft for each cylinder a throttle is located in the fuel/air inlet having less than 10% of the cylinder swept volume between the throttle seat and the inlet valve seat.
The two retractable cams per cylinder are extended for highest power but are retracted for 4 stroke operation above half load with the fuel injector in the part time air only' inlet port switched on. The cams remain retracted for alternate air only' inductions under half load using the fuel efficient 8 Stroke or Blackburn Cycle.
006 Where there are retractable cams for both inlet valves in a cylinder a separate throttle is needed in the fuel/air inlet port. However, when there is only one retractable cam for an inlet valve in an engine cylinder, this retractable cam can move to any position from fully extended to fully retracted thus opening inlet valve(s) by variable amounts controlling the fuel/air intake and the power of an engine in place of a throttle.
007 A fixed cam is operable in 8 Stroke mode with inlet valve(s) in an engine cylinder to admit alternate air only' inductions through this valve(s), while the fuel/air for combustion is controlled for an adjacent induction stroke by a variable opening retractable cam for its respective inlet valve.
008 Thus if 60% load is needed the air only' valve now gives 100% load on alternate 4 stroke cycles with its fuel injector on and the retractable cam, is about 20% extended, giving 20% load on alternate cycles. 100% plus 20% = l20% load over two 4 stroke cycles or an average of 60% total load overall.
009 The retractable cam itself is extended and retracted by a mechanism within the camshaft which can be mechanical, electrical or hydraulically operated or any other means which can extend and retract the cam itself. The method shown is the axial movement of a wedge within the camshaft which is controlled by a rod linked to an accelerator pedal.
When the retractable cam is extended and retracted by the axial movement of a wedge within the camshaft this movement is also operable by a servo, hydraulic pressure, computer or other means influenced by driver requirements and electronic control.
011 The sides of the retractable cam are shown rounded so that the corresponding cavity in the camshaft can be easily machined using a milling cutter.
012 The curved outer surface of the wedge is slideable along a bore through the camshaft while the tapered inner surface contacts the inner surface of the retractable cam. An axial spring returns the wedge to the cam retracted position. Within the cam a smaller spring is fitted between a spring locator, resting against the camshaft bore, and the wedge end of the retractable cam to maintain the cam in the retracted position.
013 A multi-cylinder engine has additional sets of retractable cams for each cylinder and usual associated parts. In place of two inlet valves in a cylinder there may be more than one fuel/air inlet valves and more than one air only' inlet valves.
014 Each wedge contacts an adjacent wedge directly or via a spacer (not shown) to transmit the control movement to each retractable cam(s) for other cylinders in turn, of a multi-cylinder engine which also includes other usual components.
An odd number of cylinders gives smoother running with retractable cams in both 4 stroke and 8 Stroke modes.
DESCRIPTION OF THE DRAWINGS
Fig I shows a section through a twin retractable cam assembly for one cylinder with the retractable cams extended.
Fig 2 shows a section as fig I with the two retractable cams retracted.
Fig 3 shows a section through a single retractable cam assembly for one cylinder with the cam extended corresponding to full power through the corresponding inlet valve.
Fig 4 shows a section as fig 3 with the cam retracted for zero load through the corresponding valve..
Fig 5 shows a section through the cam extended.
Fig 6 shows a section through the cam retracted Fig 7 Shows a plan view of the retractable cam showing the rounded cam sides.
Figure 1 shows a camshaft I with a bore 2 and control rod 3 which slides wedges 4 along bore 2 to extend cams 5 & 6 and compress small springs 7 and axial spring 8.
This creates one fixed cain 10 and one retractable cam 5 on one side of a camshaft and one fixed cam 11 and one retractable cam 6 on the other side of a camshaft driven at /. crankshaft speed.
Figure 2 shows the same assembly for one cylinder where axial spring 8 has moved wedges 4 to allow the retractable cams to retract ftilly moved by smaller springs 7 inserted between bore 2 using locator 9. Fixed cams 10 & I I on opposite sides of the camshaft driven at /4 crankshaft speed then open the two inlet valves (not shown) for alternate induction strokes. A throttle (not shown) is needed close to the fuel/air inlet valve.
Figure 3 shows a section through a camshaft with a retractable cam 5 fully extended corresponding to half average load when this cam opens a fuel/air inlet valve (not shown) on alternate 4 stroke cycles as the camshaft is driven at crankshaft speed.
Fixed cam 11 opens the other inlet valve to admit air only' for the fuel efficient alternate air only' 8 stroke or Blackburn cycle. When higher power is required a fuel injector associated with fixed cam 11 is then switched on giving alternate fuel/air inductions in place of air only' inductions to add to variable fuel/air inductions through the inlet valve opened by the retractable cam 5.
Figure 4 shows the same section as Figure 3 with retractable cam 5 fully retracted corresponding to no fuel/air and no power through its associated inlet valve. Fixed cam I I opens its associated inlet valve fully to admit either air only' or a full charge of fuel/air when this fuel injector is switched on according to the power demanded Figure 5 shows a section through the retractable cam fully extended by wedge 4 as it would appear in figure 3 which has no fixed cam on the opposite side of the camshaft. Figure 6 shows the same section with the cam fully retracted. Figure 7 shows rounded sides of the retractable cam so that the cavity in the camshaft can be easily machined using a milling cutter.
Claims (14)
1 An 8 Stroke and 4 Stroke cycle change engine where at least one inlet cam operable with at least one inlet valve in an engine cylinder is retractable within a camshaft causing an inlet valve to remain closed for an induction stroke with provision for the cam to extend to open an inlet valve for other induction strokes.
2 An 8 Stroke and 4 Stroke cycle change engine as claimed in claim 1 where there are two retractable cams located Ofl Opposite sides of the camshaft operable with two or more inlet valves for each cylinder so that all inlet valves open for adjacent induction strokes when the cams are extended but the inlet valves open for alternate induction strokes when the cams are retracted using fixed cams which are also on Opposite sides of a camshaft driven at 1/4 crankshaft speed.
3 An 8 Stroke and 4 Stroke cycle change engine as claimed in claim I where a retractable cam when extended opens and closes an inlet valve with approximately 60 degrees of camshaft rotation and where the cam form is concave at the point where the retractable cam starts to open and ends closing an inlet valve.
4 An 8 Stroke and 4 Stroke cycle change engine as claimed in claim 1 where there are two retractable cams on opposite sides of a camshaft for each cylinder and where a throttle is located in the fuel/air inlet leaving less than 10% of the cylinder swept volume between the throttle seat and the inlet valve seat.
An 8 Stroke and 4 Stroke cycle change engine as claimed in claim I where a retractable cam is operable with inlet valve(s) in a cylinder which can move to any position from fully extended to fully retracted thus controlling the fuel/air intake and the power of an engine.
6 An 8 Stroke and 4 Stroke cycle change engine as claimed in claim 5 where a fixed cam is operable in 8 Stroke mode with inlet valve(s) in an engine cylinder to admit alternate air only' inductions through this valve(s) while the fuel/air for combustion is controlled for an adjacent induction stroke by a variable retractable cam.
----
An 8 Stroke and 4 Stroke cycle change engine as claimed in claim I where the retractable cain itself is extended and retracted by a mechanism within the camshaft which can be mechanical, electrical or hydraulically operated or any other means which can extend and retract the cam itself.
8 An 8 Stroke and 4 Stroke cycle change engine as claimed in claim 1 where the retractable cam is extended and retracted by the axial movement of a wedge within the camshaft which is controlled by a rod linked to an accelerator pedal.
9 An 8 Stroke and 4 Stroke cycle change engine as claimed in claim I where the retractable cam is extended and retracted by the axial movement of a wedge within the camshaft operated by a servo, hydraulic pressure or other means influenced by driver requirements and electronic control.
An 8 Stroke and 4 Stroke cycle change engine as claimed in claim 1 where two retractable cams are extended for highest power but are retracted for 4 stroke operation above half load with fuel injection in the part time air only' inlet port and the cams remain retracted for alternate air only' inductions under half load using the 8 Stroke or Blackburn Cycle.
11 An 8 Stroke and 4 Stroke cycle change engine as claimed in claim I where the sides of the retractable cam are rounded so that the corresponding cavity in the camshaft can be easily machined using a milling cutter.
12 An 8 Stroke and 4 Stroke cycle change engine as claimed in claim I where additional sets of retractable cams and usual associated parts are used for each cylinder of a multi-cylinder engine.
13 An 8 Stroke and 4 Stroke cycle change engine as claimed in claim I where an odd number of cylinders gives smoother running with retractable earns in both 4 stroke arid 8 Stroke modes.
14 An 8 Stroke and 4 Stroke cycle change engine as described or as shown in the d wings 1/3, 2/3, and 3/3, figures 1 -7.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| GB0622278A GB2443690B (en) | 2006-11-09 | 2006-11-09 | Retractable cam |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| GB0622278A GB2443690B (en) | 2006-11-09 | 2006-11-09 | Retractable cam |
Publications (3)
| Publication Number | Publication Date |
|---|---|
| GB0622278D0 GB0622278D0 (en) | 2006-12-20 |
| GB2443690A true GB2443690A (en) | 2008-05-14 |
| GB2443690B GB2443690B (en) | 2011-10-12 |
Family
ID=37594564
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| GB0622278A Expired - Fee Related GB2443690B (en) | 2006-11-09 | 2006-11-09 | Retractable cam |
Country Status (1)
| Country | Link |
|---|---|
| GB (1) | GB2443690B (en) |
Cited By (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN102808670A (en) * | 2012-08-30 | 2012-12-05 | 上海交通大学 | Air intake/exhaust valve lift-variable system in air intake pressure regulating type |
| CN102926835A (en) * | 2012-10-12 | 2013-02-13 | 上海交通大学 | Two-valve stroke synchronously-variable device |
| CN102926834A (en) * | 2012-10-12 | 2013-02-13 | 上海交通大学 | Mechanical type valve stroke continuously-variable device |
| CN102966403A (en) * | 2012-11-12 | 2013-03-13 | 上海交通大学 | Device for adjusting lift of intake valve of supercharged engine |
Citations (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| GB2402708A (en) * | 2003-06-11 | 2004-12-15 | Thomas Tsoi Hei Ma | Selectable two-stroke/four-stroke lost-motion valve actuation system for i.c. engines |
| US6928970B2 (en) * | 2001-08-24 | 2005-08-16 | Robert Bosch Gmbh | Device for the variable control of gas exchange valves in an internal combustion engine |
| JP2006342724A (en) * | 2005-06-09 | 2006-12-21 | Yamaha Motor Co Ltd | Valve mechanism and engine equipped with it, and vehicle |
-
2006
- 2006-11-09 GB GB0622278A patent/GB2443690B/en not_active Expired - Fee Related
Patent Citations (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US6928970B2 (en) * | 2001-08-24 | 2005-08-16 | Robert Bosch Gmbh | Device for the variable control of gas exchange valves in an internal combustion engine |
| GB2402708A (en) * | 2003-06-11 | 2004-12-15 | Thomas Tsoi Hei Ma | Selectable two-stroke/four-stroke lost-motion valve actuation system for i.c. engines |
| JP2006342724A (en) * | 2005-06-09 | 2006-12-21 | Yamaha Motor Co Ltd | Valve mechanism and engine equipped with it, and vehicle |
Cited By (6)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN102808670A (en) * | 2012-08-30 | 2012-12-05 | 上海交通大学 | Air intake/exhaust valve lift-variable system in air intake pressure regulating type |
| CN102926835A (en) * | 2012-10-12 | 2013-02-13 | 上海交通大学 | Two-valve stroke synchronously-variable device |
| CN102926834A (en) * | 2012-10-12 | 2013-02-13 | 上海交通大学 | Mechanical type valve stroke continuously-variable device |
| CN102926834B (en) * | 2012-10-12 | 2014-11-19 | 上海交通大学 | Mechanical type valve stroke continuously-variable device |
| CN102966403A (en) * | 2012-11-12 | 2013-03-13 | 上海交通大学 | Device for adjusting lift of intake valve of supercharged engine |
| CN102966403B (en) * | 2012-11-12 | 2014-12-24 | 上海交通大学 | Device for adjusting lift of intake valve of supercharged engine |
Also Published As
| Publication number | Publication date |
|---|---|
| GB2443690B (en) | 2011-10-12 |
| GB0622278D0 (en) | 2006-12-20 |
Similar Documents
| Publication | Publication Date | Title |
|---|---|---|
| US8413619B2 (en) | Variable compression ratio systems for opposed-piston and other internal combustion engines, and related methods of manufacture and use | |
| US8307792B2 (en) | Mechanism for internal combustion piston engines | |
| US6250266B1 (en) | Variable valve timing mechanism for engine | |
| KR101396736B1 (en) | Internal combustion engine with variable valve gear | |
| EP0705383B1 (en) | Valve mechanism for an internal combustion engine | |
| EP1409853B1 (en) | Hydraulic valve actuation systems and methods | |
| EP1712760B1 (en) | Indirect variable valve actuation for an internal combustion engine | |
| US7204214B2 (en) | Multi-cylinder internal combustion engine | |
| FI121512B (en) | Control arrangement for a suction valve in a piston engine | |
| CZ296604B6 (en) | Internal combustion engine | |
| JP2006291962A5 (en) | ||
| US10190492B2 (en) | Dual crankshaft, opposed-piston engines with variable crank phasing | |
| WO2023089464A1 (en) | Multi-cylinder internal combustion engine, with cylinders equipped with intake valve variable actuation systems having hydraulic circuits which cross each other | |
| GB2443690A (en) | Retractable cam system for an 8-stroke and 4-stroke cycle change engine | |
| EP2803828B1 (en) | A spark ignition internal combustion engine having intake valves with variable actuation and delayed closure | |
| US5027753A (en) | Intake system of multi-cylinder internal combustion engine | |
| US7077083B2 (en) | Electro-hydraulic lost-motion valve train | |
| US20100242919A1 (en) | Constant Compression Engine Using a Preferably Toroidal Volume Control Slider | |
| JP2017115850A (en) | System for variably operating valve of internal combustion engine | |
| US20100006054A1 (en) | Internal combustion engine having guillotine sliding valve | |
| EP3184761B1 (en) | System for variable actuation of a valve of an internal-combustion engine | |
| US20170306869A1 (en) | Diesel engine and method for starting a diesel engine | |
| JPS58167822A (en) | Supercharge device of 4-cycle engine | |
| US7574982B2 (en) | Engine cycles | |
| US9404428B1 (en) | Variable-expansion-ratio engine |
Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| PCNP | Patent ceased through non-payment of renewal fee |
Effective date: 20120112 |