EP0414064A2 - Piston à hauteur de compression variable pour moteurs à combustion - Google Patents

Piston à hauteur de compression variable pour moteurs à combustion Download PDF

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Publication number
EP0414064A2
EP0414064A2 EP90115367A EP90115367A EP0414064A2 EP 0414064 A2 EP0414064 A2 EP 0414064A2 EP 90115367 A EP90115367 A EP 90115367A EP 90115367 A EP90115367 A EP 90115367A EP 0414064 A2 EP0414064 A2 EP 0414064A2
Authority
EP
European Patent Office
Prior art keywords
piston
oil
control chamber
plunger according
valve
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Withdrawn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
EP90115367A
Other languages
German (de)
English (en)
Other versions
EP0414064A3 (en
Inventor
Wolfgang Bierkant
Peter Kemnitz
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.)
Mahle GmbH
Original Assignee
Mahle GmbH
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
Priority claimed from DE19893927521 external-priority patent/DE3927521C2/de
Priority claimed from DE19904022508 external-priority patent/DE4022508C2/de
Application filed by Mahle GmbH filed Critical Mahle GmbH
Publication of EP0414064A2 publication Critical patent/EP0414064A2/fr
Publication of EP0414064A3 publication Critical patent/EP0414064A3/de
Withdrawn legal-status Critical Current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
    • F02B75/00—Other engines
    • F02B75/04—Engines with variable distances between pistons at top dead-centre positions and cylinder heads
    • F02B75/044—Engines with variable distances between pistons at top dead-centre positions and cylinder heads by means of an adjustable piston length
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F05—INDEXING SCHEMES RELATING TO ENGINES OR PUMPS IN VARIOUS SUBCLASSES OF CLASSES F01-F04
    • F05C—INDEXING SCHEME RELATING TO MATERIALS, MATERIAL PROPERTIES OR MATERIAL CHARACTERISTICS FOR MACHINES, ENGINES OR PUMPS OTHER THAN NON-POSITIVE-DISPLACEMENT MACHINES OR ENGINES
    • F05C2201/00—Metals
    • F05C2201/04—Heavy metals
    • F05C2201/0433—Iron group; Ferrous alloys, e.g. steel
    • F05C2201/0448—Steel

Definitions

  • the invention relates to a plunger with a variable compression height for internal combustion engines according to the preambles of claims 1 and 10.
  • Such pistons are known for example from DE 27 19 043 C2 and US 32 05 878.
  • the object of the invention is to improve the function of the individual valves.
  • these valves should have the smallest possible mass to be moved and require the smallest possible installation space in the direction of the piston axis.
  • the parts of the piston which are relatively movable in the axial direction are an upper piston part 1 and a lower piston part 2.
  • the upper piston part 1 in turn consists of the piston crown 3 with the ring grooves 4, to which a locking ring 5 is attached from the open side.
  • the lower piston part 2 essentially consists of a base body 6 with the shaft and the hubs as well as a cover plate 7 attached to the end of the base body facing the piston head 3 and projecting radially beyond the base body 6.
  • the upper piston part 1 is guided to be longitudinally displaceable on the outer circumference of the cover plate 7, the locking ring 5 striking the cover plate 7 from below at the maximum compression height.
  • the control chamber 8 of the piston is located between the cover plate 7 and the piston crown 3, while the damping chamber 9 is formed by the annular space between the cover plate 7 and the locking ring 5.
  • the pressure relief valve 10 for the control chamber 8 is located at the lower end of the base body 6 and is connected to the control chamber 8 via a line 11.
  • the pressure oil supply valve for the control chamber 8 is a tongue-shaped lamella 12, which acts as a one-way valve only allows oil to flow into the control chamber 8 while blocking a backflow.
  • the lamella 12 is part of a membrane plate 13 made of flexible, uniform material and clamped between the base body 6 and the cover plate 7.
  • the function of the one-way valve designed as a tongue-shaped lamella 12 is as follows.
  • the lamella 12 lies flat on a correspondingly designed counter surface of the base body 6.
  • this counter surface of the base body 6 there is an opening of an oil supply line 15 covered by the lamella 12.
  • On the side of the lamella 12 facing away from the opening of the oil supply line 15 there is a cavity 16 in the cover plate 7 which allows the lamella 12 to be lifted off.
  • This cavity 16 is in turn connected to the control chamber 8 via bores 17. If there is a higher pressure on the inflow side of the lamella 12 than on the outflow side, the lamella 12 opens and allows oil to enter the control chamber 8. As soon as the pressure on the downstream side in the control chamber 8 has become greater than that pressure on the upstream side of the lamella 12, the lamella acts to prevent backflow.
  • the closing of the slat is supported or accelerated by the spring force stored when opening.
  • the control is on the membrane plate 13 Erkhunt 8 with the damping chamber 9 connecting one-way valve formed as a further tongue-shaped lamella 18.
  • This lamella 18 covers the opening of a channel 19 penetrating the cover plate 7 and opening into the control chamber 8.
  • a flat cavity 20 is formed in the base body 6, which is connected to the damping chamber.
  • the lamella 18 Since the valve connecting the two chambers 8 and 9 should not only function as a one-way valve, but at the same time as a throttle valve for an oil return from the damping chamber 9 into the control chamber 8, the lamella 18 has a throttle bore 21 in the region of the opening of the channel 19 a diameter of about 0.3-0.5 mm with a piston diameter of about 100 mm.
  • This throttle bore 21 has the effect that the piston crown can be moved slightly in the direction of the increase in the compression height relative to the base body 6 with each upward stroke. As a result, the desired compression height increase of the piston is achieved at combustion chamber pressures which do not yet cause the pressure limiting valve 6 to open.
  • the advantage of the invention consists in particular in an extremely compact design of the valves formed by the lamellae 12 and 18.
  • This compact design means that the valve masses to be moved are extremely small, which means that the valves respond quickly and the wear behavior of the valves is considerably improved becomes.
  • the membrane plate 13 can be made of steel, metal, plastic or another elastic material.
  • a plurality of membrane plates 13 of the same or different thickness can also be layered in order to obtain a corresponding spring characteristic of the lamellae 12, 18. Due to a disk-shaped or ring-shaped design of the membrane plate, it can be clamped on the base body 6 practically like a seal through the cover plate 7.
  • the membrane plate 13 can also be coated on one or both sides with elastic material in order to additionally achieve a seal at the openings between the upper and lower part.
  • the arrangement of the throttle bore 21 in the lamella 18 saves a separate nozzle and, on the one hand, prevents the opening 21 from being clogged by the very short bore and, on the other hand, by the continuous movement of the lamella 18.
  • the lamella shape is expediently chosen so that it corresponds approximately to a beam of the same bend. This can also be achieved by appropriately shaped bores or slots in the lamella 12, 18.
  • the contact surface 14 in the cavities 16, 20 for the slats 12, 18 to limit the opening stroke can be designed so that their respective shape corresponds to the bending line of the slats 12, 18 or at least approximates it.
  • the piston according to FIGS. 4-8 again consists of an outer and an inner part 100 and 200. In terms of structure and function, these two parts are comparable to the relevant parts 1 and 2 of the first exemplary embodiment. This also applies to piston pins 300 and 3.
  • a control chamber 400 and a damping chamber 500 are located between the outer piston part 100 and the inner piston part 200, both of which are filled with oil during engine operation.
  • the two chambers 400 and 500 are connected to one another via a one-way overflow valve 600.
  • the structure of this valve according to the invention and the other valves to be described will be discussed in more detail below.
  • the damping chamber 500 can only be supplied with oil from the control chamber 400. Oil flowing out of the damping chamber 500 can only get into the control chamber 400.
  • the one-way overflow valve is provided with a throttle bore 700 which is constantly open. The oil enters control chamber 400 through one-way inlet valve 800.
  • Oil to be drained from the control chamber 400 passes through one or both of the one-way pressure relief valves 900.
  • the individual valves 600, 800 and 900 are each formed by openings covered by a closure part.
  • the closure parts are tongues made of resilient material, which are made in one piece from a membrane plate 110.
  • the membrane plate 110 consists of a thin, flexible metal and is fixed in relation to the valve openings via a pressure plate 111.
  • the respective tongues each spring out of themselves.
  • the tongues of the pressure relief valves 900 are preloaded by additional springs 114 or 115 in the direction of a closure of the relevant valves.
  • the spring 114 is a leaf spring
  • the spring 115 is a coil spring.
  • special bearings can be provided between the springs 114 and 115 and the free-swinging end region of the tongues of the valves 900.
  • a kind of rivet 116 for example made of plastic, is attached to the free end of the tongue, on the curved rivet head of which the helical spring 115 can be supported and centered.
  • the rivet fastening is designed such that it can be freely accommodated in the valve opening when the valve is closed.
  • the contact pressure of the coil spring 115 is adjustable via a screw 117.
  • a division of the pressure relief valve 900 into two valves makes it possible to design each of these two valves with a different opening response pressure. In this way it can be achieved that with a large pressure increase in the combustion chamber acted upon by the piston both valves 900 open, whereas at a lower pressure only one of the two valves 900 is open.
  • the opening of both valves 900 with a large pressure increase brings about a rapid reduction in the compression height, while such a compression height reduction takes place more slowly with lower valve chamber ratios when only one valve 900 is open.
  • valve design according to the invention is that all the valves have tongues formed together from a membrane plate 210, which as valve closure parts do not require any special guidance and storage and, overall, are extremely space-saving.

Landscapes

  • Engineering & Computer Science (AREA)
  • Chemical & Material Sciences (AREA)
  • Combustion & Propulsion (AREA)
  • Mechanical Engineering (AREA)
  • General Engineering & Computer Science (AREA)
  • Output Control And Ontrol Of Special Type Engine (AREA)
EP19900115367 1989-08-21 1990-08-10 Piston with a variable headroom for combustion engines Withdrawn EP0414064A3 (en)

Applications Claiming Priority (4)

Application Number Priority Date Filing Date Title
DE19893927521 DE3927521C2 (de) 1989-08-21 1989-08-21 Tauchkolben mit variabler Kompressionshöhe für Verbrennungsmotoren
DE3927521 1989-08-21
DE4022508 1990-07-14
DE19904022508 DE4022508C2 (de) 1990-07-14 1990-07-14 Tauchkolben mit variabler Kompressionshöhe

Publications (2)

Publication Number Publication Date
EP0414064A2 true EP0414064A2 (fr) 1991-02-27
EP0414064A3 EP0414064A3 (en) 1991-09-11

Family

ID=25884210

Family Applications (1)

Application Number Title Priority Date Filing Date
EP19900115367 Withdrawn EP0414064A3 (en) 1989-08-21 1990-08-10 Piston with a variable headroom for combustion engines

Country Status (1)

Country Link
EP (1) EP0414064A3 (fr)

Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE29613109U1 (de) * 1996-07-18 1997-11-13 Pollerhoff Holger Kolben mit Eigenoszillation für Verbrennungskraftmaschinen

Citations (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE2719043A1 (de) * 1977-04-28 1978-11-02 Teledyne Ind Kolben fuer eine brennkraftmaschine mit veraenderbarem kompressionsverhaeltnis
DE3416346A1 (de) * 1984-05-03 1985-11-07 Mahle Gmbh, 7000 Stuttgart Kolben mit veraenderlicher kompressionshoehe fuer verbrennungsmotoren

Patent Citations (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE2719043A1 (de) * 1977-04-28 1978-11-02 Teledyne Ind Kolben fuer eine brennkraftmaschine mit veraenderbarem kompressionsverhaeltnis
DE3416346A1 (de) * 1984-05-03 1985-11-07 Mahle Gmbh, 7000 Stuttgart Kolben mit veraenderlicher kompressionshoehe fuer verbrennungsmotoren

Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE29613109U1 (de) * 1996-07-18 1997-11-13 Pollerhoff Holger Kolben mit Eigenoszillation für Verbrennungskraftmaschinen

Also Published As

Publication number Publication date
EP0414064A3 (en) 1991-09-11

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