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
  • F01L7/00—Rotary or oscillatory slide valve-gear or valve arrangements
  • F01L7/02—Rotary or oscillatory slide valve-gear or valve arrangements with cylindrical, sleeve, or part-annularly shaped valves
  • F01L7/021—Rotary or oscillatory slide valve-gear or valve arrangements with cylindrical, sleeve, or part-annularly shaped valves with one rotary valve
  • F01L7/022—Cylindrical valves having one recess communicating successively with aligned inlet and exhaust ports
• • 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
  • F02B33/26—Four-stroke engines characterised by having crankcase pumps
• • 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
  • F01L7/00—Rotary or oscillatory slide valve-gear or valve arrangements
  • F01L7/02—Rotary or oscillatory slide valve-gear or valve arrangements with cylindrical, sleeve, or part-annularly shaped valves
  • F01L7/021—Rotary or oscillatory slide valve-gear or valve arrangements with cylindrical, sleeve, or part-annularly shaped valves with one rotary valve
• • 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

Definitions

• the present invention relates to a compact four-stroke internal combustion engine according to the preamble of claim 1.
• Such an engine which works with mixed lubrication and is primarily suitable for use in a portable working device, e.g. a brushcutter or a chain saw, is e.g. known from the document DE-A1-42 20 200.
• a four-stroke internal combustion engine with oil lubrication is known from the prior art, the oil being stored separately from the fuel.
• the oil is pumped to the appropriate lubrication points, or reaches the lubrication points from an oil sump as an oil-air mixture (oil mist).
• Engine lubrication with a fuel-oil-air mixture similar to the lubrication of two-stroke engines is also known.
• the fuel-oil-air mixture is stored in the crankcase and fed to the rotary valve inlet via a line.
• a backflow of the fresh gas into the carburetor is avoided by a membrane valve (see DE-A1-42 20 200 mentioned at the beginning).
• the object is achieved by the entirety of the features of claim 1.
• the essence of the invention is not only to control the filling and emptying of the combustion chamber via a single rotary slide valve, but also to temporarily direct a part of the mixture into the combined cylinder / crankcase chamber and then to flow back out of the cylinder / crankcase chamber to fill the combustion chamber allow.
• the combustion chamber is primarily filled directly by the mixture coming from the carburetor.
• the additional mixture coming from the KGH room supports the filling. This makes it possible to ensure an adapted, position-independent lubrication with a compact structure and short conduits.
• a reloading effect is achieved through the additional mixture that comes from the KGH area.
• the rotary valve is arranged in the cylinder head, and the rotary valve from the crankshaft via a gear, which preferably :: white gears and a toothed belt is driven.
• the rotary slide valve preferably comprises a cylindrical body, in which two channels and a cutout are provided for realizing the connections.
• the channels can also be realized as a recess and the recess as channels.
• the body is not necessarily cylindrical, other shapes such as spheres or spherical bodies are also suitable.
• FIG. 1 is a side view of the drive of the rotary valve a preferred embodiment of a four-stroke
• FIG. 2 in a jumping sectional view of the engine of Fig. 1;
• FIG. 3 shows a detail of a cross section through the rotary slide valve of the engine from FIG. 2 mounted in the cylinder head;
• FIG. 4-7 in a perspective longitudinal sectional view, four different phases in the operation of the engine according to FIG. 2, each differing by a crankshaft angle of 90 °, FIG. 4 relating to the position of the piston at top dead center (TDC) and FIG 6 refer to the position of the piston at bottom dead center (UT), and FIGS. 5 and 7 each show the piston position of 90 ° after or before top dead center.
• TDC top dead center
• UT bottom dead center
• FIGS. 5 and 7 each show the piston position of 90 ° after or before top dead center.
• the four-stroke internal combustion engine 100 which is shown as a preferred exemplary embodiment of the invention in FIGS. 1 to 3, essentially consists of a cylinder 9 with a piston 11 sliding up and down therein, and a crankcase 20, which connects to the cylinder 9 below, wherein KGH 20 and cylinder 9 can also consist of one piece, and a cylinder head 1 with combustion chamber 4, which connects to the cylinder 9 above, wherein the cylinder 9 and cylinder head 1 can also consist of one piece.
• a cylindrical rotary slide valve 2 is arranged in the cylinder head 1 and has several control openings: an inlet opening 5 to a carburetor 3, an outlet opening 6 to an outlet duct 7 and an opening to an overflow duct 8 with connection to the cylinder 9 and an opening to the combustion chamber 4.
• two channels 17 and 19 and a recess 18 are arranged so that connections between the carburetor 3 and the combustion chamber 4, the carburetor 3 and the cylinder 9, the cylinder 9 and the combustion chamber 4, and the combustion chamber 4 and exhaust duct 7 in dependence be produced from the angle of rotation of the rotary valve 2.
• the lubrication takes place via a fuel-oil-air mixture which is generated in the carburetor 3 in a manner known per se.
• the rotary valve 2 connects the inlet opening 5 to the combustion chamber 4 via the channel 19 (FIG. 5).
• the rotary valve 2 connects the overflow channel 8 to the combustion chamber 4 via the channel 19 (FIG. 6).
• the rotary slide valve 2 connects the combustion chamber 4 to the outlet opening 6 via the channel 17 (FIGS. 4 and 7).
• the time sequence is as follows in accordance with FIGS. 4 to 7:
• the piston 11 is at the top dead center TDC (charge exchange TDC) and generates a negative pressure in the upper region of the cylinder 9 during the downward movement, as a result of which the fuel-oil-air mixture flows from the carburetor 3 into the combustion chamber 4 (movement of FIG. 4 -> Fig. 5). Even before the piston 11 reaches bottom dead center UT, the connection between the overflow channel 8 and the combustion chamber 4 is established, so that the fuel-oil-air mixture upstream in the crankcase 20 can additionally flow into the combustion chamber 4 (FIG. 6) , During the subsequent upward movement of the piston 11 with the ignition of the mixture by the spark plug 16 and the subsequent downward movement, the control openings to the cylinder 9 / crankcase chamber 10 and combustion chamber 4 remain closed.
• TDC charge exchange TDC
• the connection to the outlet (6, 7) is made so that the piston 11 can push the exhaust gases out of the cylinder 9 (movement from Fig. 7 -> Fig. 4).
• overflow channel 8 and inlet opening 5 are released so that mixture is sucked by the piston movement from the carburetor 3 into the cylinder 9 / crankcase space 10.
• the outlet (6, 7) and the overflow channel 8 are closed again (FIG. 4).
• the rotary valve 2 can be driven by the crankshaft 12 via a belt, chain, gear or similar.
• a drive is used which comprises two gears 13, 15 and a toothed belt 14 (Fig. 1).

Landscapes

• Engineering & Computer Science (AREA)
• Mechanical Engineering (AREA)
• General Engineering & Computer Science (AREA)
• Chemical & Material Sciences (AREA)
• Combustion & Propulsion (AREA)
• Lubrication Of Internal Combustion Engines (AREA)
• Cylinder Crankcases Of Internal Combustion Engines (AREA)

Priority Applications (4)

Applications Claiming Priority (2)

Publications (1)

Family

ID=8082082

Family Applications (1)

Country Status (5)

Families Citing this family (11)

Citations (4)

Family Cites Families (7)

• 1999
  • 1999-11-25 DE DE29920719U patent/DE29920719U1/de not_active Expired - Lifetime
• 2000
  • 2000-10-31 WO PCT/EP2000/010753 patent/WO2001038705A1/de not_active Ceased
  • 2000-10-31 JP JP2001540025A patent/JP2003515043A/ja active Pending
  • 2000-10-31 US US10/130,006 patent/US6694942B1/en not_active Expired - Lifetime
  • 2000-10-31 DE DE10083635T patent/DE10083635B4/de not_active Expired - Fee Related
• 2002
  • 2002-04-25 SE SE0201238A patent/SE519785C2/sv not_active IP Right Cessation

Patent Citations (4)

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