EP3128149A1 - Moteur à deux temps - Google Patents

Moteur à deux temps Download PDF

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Publication number
EP3128149A1
EP3128149A1 EP15179826.1A EP15179826A EP3128149A1 EP 3128149 A1 EP3128149 A1 EP 3128149A1 EP 15179826 A EP15179826 A EP 15179826A EP 3128149 A1 EP3128149 A1 EP 3128149A1
Authority
EP
European Patent Office
Prior art keywords
cylinder
piston
engine according
diameter
inlet
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Withdrawn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
EP15179826.1A
Other languages
German (de)
English (en)
Inventor
Gerrit Hendrik Gerrits
Danny Walter Aumiller
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.)
Ryger Engine United BV
Original Assignee
Ryger Engine United BV
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 Ryger Engine United BV filed Critical Ryger Engine United BV
Priority to EP15179826.1A priority Critical patent/EP3128149A1/fr
Publication of EP3128149A1 publication Critical patent/EP3128149A1/fr
Withdrawn legal-status Critical Current

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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
    • F02B33/00—Engines characterised by provision of pumps for charging or scavenging
    • F02B33/02—Engines with reciprocating-piston pumps; Engines with crankcase pumps
    • F02B33/06—Engines with reciprocating-piston pumps; Engines with crankcase pumps with reciprocating-piston pumps other than simple crankcase pumps
    • F02B33/10—Engines with reciprocating-piston pumps; Engines with crankcase pumps with reciprocating-piston pumps other than simple crankcase pumps with the pumping cylinder situated between working cylinder and crankcase, or with the pumping cylinder surrounding working cylinder
    • F02B33/12—Engines with reciprocating-piston pumps; Engines with crankcase pumps with reciprocating-piston pumps other than simple crankcase pumps with the pumping cylinder situated between working cylinder and crankcase, or with the pumping cylinder surrounding working cylinder the rear face of working piston acting as pumping member and co-operating with a pumping chamber isolated from crankcase, the connecting-rod passing through the chamber and co-operating with movable isolating member
    • 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
    • F02B33/00—Engines characterised by provision of pumps for charging or scavenging
    • F02B33/02—Engines with reciprocating-piston pumps; Engines with crankcase pumps
    • F02B33/06—Engines with reciprocating-piston pumps; Engines with crankcase pumps with reciprocating-piston pumps other than simple crankcase pumps
    • F02B33/10—Engines with reciprocating-piston pumps; Engines with crankcase pumps with reciprocating-piston pumps other than simple crankcase pumps with the pumping cylinder situated between working cylinder and crankcase, or with the pumping cylinder surrounding working cylinder
    • F02B33/14—Engines with reciprocating-piston pumps; Engines with crankcase pumps with reciprocating-piston pumps other than simple crankcase pumps with the pumping cylinder situated between working cylinder and crankcase, or with the pumping cylinder surrounding working cylinder working and pumping pistons forming stepped piston
    • 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 
    • F02F1/18—Other cylinders
    • F02F1/22—Other cylinders characterised by having ports in cylinder wall for scavenging or charging
    • 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
    • F02F3/00—Pistons 
    • F02F3/24—Pistons  having means for guiding gases in cylinders, e.g. for guiding scavenging charge in two-stroke engines
    • 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
    • F02B2075/025—Engines characterised by their cycles, e.g. six-stroke having less than six strokes per cycle two

Definitions

  • the invention relates to a two stroke internal combustion engine comprising:
  • Such a two stroke internal combustion engine is for example known from WO 2007/142512 .
  • the pumping action for sucking in air with fuel is not done via the crankcase, which is typical for a two-stroke engine, but via the space created around the bottom part of the piston, due to the reduced second diameter. Oil is present in the crankcase to lubricate different parts of the engine and it is no longer necessary to add oil to the fuel for operation of the engine.
  • the known two stroke internal combustion engine is provided with a piston having a top part with a first diameter corresponding to the inner diameter of the cylinder and having a bottom part with a second diameter, which second diameter is smaller than the first diameter.
  • the cylinder wall also has a reduced diameter at the bottom, such that a seal can be arranged between this bottom part of the piston and the bottom cylinder wall.
  • bypass channel substantially envelopes the cylinder, having inlet openings and outlet openings extending through the cylinder wall into the cylinder and wherein the inlet openings and outlet openings are distributed over the circumference of the cylinder wall and are arranged in an annular inlet configuration and an annular outlet configuration.
  • the annular outlet configuration is preferably arranged closer to the top position of the piston than the annular inlet configuration.
  • bypass channel substantially enveloping the cylinder in combination with the annular configuration of inlet openings and outlet openings, there is an optimal flow of air-fuel mixture from the inlet port under the top part of the piston resulting in an increased filling ratio of the space underneath the piston.
  • the compressed air-fuel-mixture can flow from underneath the piston, via the bypass channel, via the annular outlet configuration and flow into the cylinder space above the piston.
  • the outlet port extends through and is isolated from the annular outlet configuration.
  • the annular outlet configuration is interrupted by the outlet port.
  • the compressed air-fuel-mixture flows radially into the cylinder space above the piston, while the exhaust gases flow out of the cylinder space via the outlet port. Due to the shape of the exhaust, which typically has some kind of expansion chamber. The air-fuel-mixture is stopped from directly flowing out via the outlet port by a pulse generated by the expansion chamber.
  • the top part of the piston is provided along the circumference with a depending shield for closing the outlet port, which shield extends parallel and at a distance of the bottom part of the piston.
  • the depending shield will close the outlet port, when the top part of the piston has past the outlet port. This ensures, that fresh air-fuel-mixture from the inlet port does not directly flow to the outlet port. Furthermore, it allows for a longer compression stroke of the air-fuel-mixture below the top part of the piston. Due to the compression, the mixture will flow at a higher speed via the bypass channel into the cylinder space, resulting in more turbulence and accordingly a better mixture of air and fuel.
  • the inlet port debouches in the annular inlet configuration.
  • a one-directional valve such as a reed valve, is arranged in front of the inlet port.
  • the one-directional valve allows for intake of the air-fuel-mixture and then compression of said mixture without pushing the mixture out via the inlet port. It also allows for a pressure build up in the intake port, wherein the average pressure in the intake port is higher than the ambient pressure.
  • the top part of the piston comprises at least two circumferential grooves and wherein the top seal comprises at least two rings arranged each in one of the circumferential grooves.
  • the piston is hollow and has an access opening in the bottom and wherein at least one channel is arranged between the internal space of the piston and the circumferential surface of the top part of the piston between the at least two circumferential grooves.
  • Oil spray present in the crankcase can easily reach the piston, condense and penetrate, via the access opening, the plurality of channels due to the pressure in the crankcase, such that a small amount of oil is fed to the top seal ensuring proper sealing and lubrication of the piston relative to the cylinder wall.
  • the cylinder comprises a cylinder head arranged at the top of the cylinder to close off one end of the cylinder and a cylinder foot arranged at the bottom of the cylinder, wherein the cylinder foot is provided with an opening with a diameter corresponding to the second diameter.
  • the bottom seal is arranged in the cylinder foot.
  • a cylinder of a internal combustion engine is build out of several parts, one of which is the cylinder head.
  • the cylinder head can for example be cast, while the cylindrical wall can be made from a wear resistant material.
  • the cylinder according to the invention also has a cylinder foot, which provides a body in which the bottom seal can be arranged and which can be adapted to the reduced second diameter of the bottom part of the piston.
  • the bottom seal is arranged in the cylinder wall.
  • the seal of the known engine is provided in a conventional way by arranging one or more circumferential grooves in the bottom part of the piston and with rings arranged in the circumferential grooves.
  • a disadvantages of this arrangement is that the overall height of the engine is considerable, as the cylinder height is at least the distance between the top position and the bottom position of the piston increased with the distance between the top seal and the bottom seal. This cylinder height is required as both the top seal and the bottom seal need to be in contact with the cylinder wall at all times.
  • the pumping chamber defined between the cylinder wall and the bottom part of the piston is still sealed, while the overall height of the engine is reduced considerably.
  • the cylinder height is only the distance between the top position and the bottom position of the piston increased with some addition height for arranging the bottom seal in the cylinder wall.
  • the cylinder wall comprises on the inner wall at least one circumferential groove and the bottom seal comprises at least one ring arranged in the at least one circumferential groove.
  • Typical sealing rings known in the prior art are arranged on the piston in a groove and are compressed during assembly, such that the sealing rings exert a radially outward directed force.
  • the ring needs to be expanded during assembly and will exert a radially inward directed force, such that the ring is clamped around the piston and provides a sealing in combination with the circumferential groove, in which the ring is positioned.
  • the length of the bottom part of the piston is larger than the distance between the top position and the bottom position of the piston.
  • the combined volume of the bypass channel and the inlet port is larger than the cylinder volume.
  • the bottom part of the piston is provided with a friction reducing coating.
  • a friction reducing coating contributes to smooth running of the engine and increasing the fuel efficiency as the internal friction will be reduced by this coating.
  • the outlet port 6 is connected to an exhaust muffler 12.
  • a bypass channel 23 is provided (see figure 4 ) having inlet openings 30 and outlet openings 31 extending through the cylinder wall into the cylinder 2.
  • the inlet openings 30 and outlet openings 31 are distributed over the circumference of the cylinder wall and are arranged in an annular inlet configuration and an annular outlet configuration.
  • a piston 13, 14 is movably arranged.
  • the piston 13, 14 has a top part 13 provided with two circumferential grooves.
  • This top part 13 has a first diameter, which corresponds to the diameter of the cylinder 2.
  • the piston 13, 14 has further a bottom part 14 with a reduced second diameter, such that a pumping chamber 15 is provided between the bottom part 14 and the cylinder 2.
  • the cylinder foot 4 is provided with an opening 17 having two circumferential grooves 16 for seating sealing rings. The diameter of the opening 17 corresponds to the second diameter of the bottom part 14 of the piston 13, 14.
  • the piston 13, 14 is connected via a drive rod 18 to a crankshaft 19 housed in a crankshaft casing 20.
  • crankshaft casing venting tube 50 is provided between the crankshaft casing 20 and an oil separator 51.
  • This oil separator 51 vents air via a filter 52 arranged on the top, while oil is drained at the bottom and fed back via channel 53 to the crankshaft casing 20.
  • a valve 54 arranged in the venting tube 50 allows one to adjust the pressure in the crankshaft casing 20 and accordingly how much oil is supplied to the sealing rings in the grooves 16. The pressure may be either controlled manually or automatically. A higher pressure results in a higher rotational speed and increased oil thickness or viscosity.
  • Figure 2 shows the position of the engine 1, in which the piston 13, 14 has moved further down, such that a direct connection arises between the space 21 and the outlet port 6. Due to the combustion of the air-fuel mixture, the gases G, will flow out via the outlet port 6.
  • the piston 13, 14 is hollow having an access opening 25 at the bottom, such that oil spray O can enter the inside of the piston 13, 14.
  • the piston 13, 14 is provided with a number of grooves 26 via which the oil spray O can enter for lubrication of rings arranged in these grooves 26.
  • circumferential grooves 26 are arranged in the cylinder foot 4 and accommodate sealing rings, which provide an inwardly directed spring force on the bottom part 14 of the piston 13, 14 for sealing.
  • the height of the cylinder is mainly determined by the stroke of the piston 13, 14 in the cylinder 2 and the space required in the cylinder foot 4 for providing the sealing means comprising the circumferential grooves 16 and the rings accommodated therein.
  • Figure 6 shows a perspective view of a piston 40 for the engine according to the invention.
  • the piston 40 has a top part 41 with a diameter corresponding to the inner diameter of the cylinder and a bottom part 42 with a smaller diameter.
  • the top part 41 has two circumferential grooves 43 for seating sealing rings. Between the two grooves 43 an opening 44 of a channel is positioned. This channel connects the opening 44 with the hollow interior and open bottom of the piston 40.
  • a shield 45 depends from the top part 41 and is used for closing the outlet port of the cylinder.
  • a through hole 45 is arranged for seating the gudgeon pin 46.
  • the gudgeon pin 46 connects the piston 40 to the drive rod. Because the through hole 45 is arranged in the piston as a non-composite hole, i.e. made in one single material, the forces of the drive rod are optimally transferred on to the piston 40.
  • a cover plate 47 is slided in axial direction into the slot 48 in front of the hole 45, to prevent the gudgeon pin 46 from moving out of the through hole 45.
  • the opening 44 is provided for providing oil between the seals arranged in the grooves 43.
  • Figure 7 shows a detail of the sealing rings 55 arranged in the groove 16 in the cylinder wall 56.
  • the sealing rings 55 are spaced apart by a spacer ring 57.
  • Each ring 55 has a slanting inner surface 58, which ensures that any excess oil is moved downwardly towards the crankshaft casing 20. Furthermore, the slanting surface 58 contributes in generating an air cushion between the sealing rings 55, which will provide a bearing for the piston 14, when the piston 14 moves up and down.
  • Figure 8 shows a side view of the rings 55 and spacer ring 57.
  • the lock 59, 60 present in the sealing rings 55 is mirrored with respect to the two sealing rings 55. This further contributes in providing an air cushion.
  • Figure 9 shows a top view of a similar embodiment 100, showing cylinder head 102, with inlet openings 130 and outlet openings 131 in connection with bypass channel 123, as well as outlet port 106.

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)
EP15179826.1A 2015-08-05 2015-08-05 Moteur à deux temps Withdrawn EP3128149A1 (fr)

Priority Applications (1)

Application Number Priority Date Filing Date Title
EP15179826.1A EP3128149A1 (fr) 2015-08-05 2015-08-05 Moteur à deux temps

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
EP15179826.1A EP3128149A1 (fr) 2015-08-05 2015-08-05 Moteur à deux temps

Publications (1)

Publication Number Publication Date
EP3128149A1 true EP3128149A1 (fr) 2017-02-08

Family

ID=53783122

Family Applications (1)

Application Number Title Priority Date Filing Date
EP15179826.1A Withdrawn EP3128149A1 (fr) 2015-08-05 2015-08-05 Moteur à deux temps

Country Status (1)

Country Link
EP (1) EP3128149A1 (fr)

Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US10690043B2 (en) 2018-04-18 2020-06-23 Boyesen, Inc. Two-stroke engine and components thereof

Citations (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPS5879621A (ja) * 1981-11-07 1983-05-13 Yamaha Motor Co Ltd ２サイクルエンジン
US6145488A (en) * 1999-07-15 2000-11-14 Mph Motors, Inc. Reduced volume scavenging system for two cycle engines
US20030116107A1 (en) * 1999-02-05 2003-06-26 Franz Laimbock Two-stroke internal combustion engine with crankcase scavenging
US20030200941A1 (en) * 2002-04-24 2003-10-30 Andreas Stihl Ag & Co. Kg. Two-stroke engine
WO2007142512A1 (fr) 2006-06-02 2007-12-13 Sevilla Beheer Bv Moteur à combustion interne deux-temps, bague de soupape, piston et ensemble couverture de trou de piston

Patent Citations (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPS5879621A (ja) * 1981-11-07 1983-05-13 Yamaha Motor Co Ltd ２サイクルエンジン
US20030116107A1 (en) * 1999-02-05 2003-06-26 Franz Laimbock Two-stroke internal combustion engine with crankcase scavenging
US6145488A (en) * 1999-07-15 2000-11-14 Mph Motors, Inc. Reduced volume scavenging system for two cycle engines
US20030200941A1 (en) * 2002-04-24 2003-10-30 Andreas Stihl Ag & Co. Kg. Two-stroke engine
WO2007142512A1 (fr) 2006-06-02 2007-12-13 Sevilla Beheer Bv Moteur à combustion interne deux-temps, bague de soupape, piston et ensemble couverture de trou de piston

Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US10690043B2 (en) 2018-04-18 2020-06-23 Boyesen, Inc. Two-stroke engine and components thereof

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