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
  • F01L7/06—Rotary or oscillatory slide valve-gear or valve arrangements with disc type valves

Definitions

• the present invention relates to 'internal combustion engines and more in particular to intake or induction valve systems of an ignitable mixture inside the combustion chamber of a cylinder, and to outlet or exhaust valve systems for the release of the gases produced by the combustion of the mixture.
• each cylinder requires at least one induction and one exhaust valve, commonly driven through a transmission that includes a camshaft, moved by the crankshaft of the engine.
• valves are installed in the cylinder head in which also one or more spark plugs are installed.
• the valves have a reversed mushroom-like cross section, the disk-like shutter that closes the aperture being pushed for a depth of few millimeters inside the combustion chamber by the cam or by the oscillating arm that drives the stem of the mushroom valve protruding out of the head, inside a chamber containing the camshaft and the other mechanical transmission organs of the synchronized induction and exhaust system.
• This pressure drop limits the engine performance by burdening the action of special induction and exhaust devices used to maximize the engine performances despite the limiting effects due to the encumbrance of the mushroom shutter of the intake and exhaust valves.
• a nonnegligible aspect in engines design is their overall encumbrance in function of their performance parameters and typically, in case of car engines with several cylinders in line or on a V arrangement, their "vertical" dimension.
• camshafts, pulleys, transmission belts, ..., etc. limit the possibility to reduce beyond a certain limit the "vertical" dimension of the engine.
• the inverted mushroom-like shape of the valve shutters remains a hindrance to the high speed streaming of intake and exhaust gases, by acting as a deflector.
• valve system of the invention provides the designer with an unsurpassed freedom to devise more efficient geometries by eliminating the constraints that were due to the presence of valves on the cylinder's head as well as to the presence driving organs acting on the valve stems, necessarily arranged over the engine's head (head camshaft).
• both induction and exhaust valves are realized through the wall of the cylinder whose head free of valves may be more freely designed, accounting only for the installation of the spark plug (or of more plugs).
• Each intake and exhaust device is realized with a rotating disk shutter having a window in form of a circular sector which uncovers, during its rotation, an aperture made through the cylinder wall, close to the sealing rim of the cylinder on which the engine's head (cylinder's head) is mounted.
• the rotating disk shutter is mounted on a shaft rotatably supported on a first bearing installed in the cylinder's wall and on a second thrust bearing installed in an engine's casing provided with channels for the circulation of a cooling fluid and of apertures geometrically coordinated with the valves apertures defined through the cylinder's walls.
• the sealing ring Upon assembling the motor, the sealing ring is resiliently compressed by the rotating disk shutter in the annular groove that accommodates it.
• any accidental deflection of the rotating disk will be limited by the disk eventually abutting against a contrasting surface of the casing purposely machined on the inner face of the casing.
• Such a contrasting surface may be furnished with one or more rings of an antifriction material inserted in suitable retaining cavities machined on it, onto which the rotating disk shutter may abut during possible abnormal combustion phases (blasts).
• the sealing ring being resiliently mounted on the flattened surface of the external wall of the cylinder, follows the rotating disk shutter in case of momentaneous deflections toward the contrasting surface or surfaces at the bottom of the recess housing it defined in the engine case during a stroke or gas expansion phase, thus ensuring tightness of the combustion chamber.
• each rotating disk shutter is driven through its shaft by way of adequate mechanical transmissions of the rotation of the engine's crankshaft, in synchronism with its rotating speed.
• the piston may completely cover the induction and exhaust ports with its own seal rings, while its oil scraper rings must be necessarily installed on the piston at a level such that they do not reach and surpass the bottom rim of the induction and exhaust ports to prevent a leak of oil into the intake and exhaust apertures made through the cylinder's wall.
• the oil scraper ring or rings of the piston may be placed eventually below the pin that links the piston to the rod.
• the particularly effective sealing ensured by the seal ring resiliently compressed by the rotating disk shutter may be exploited also in a two-stroke engine to enhance the performance of a rotating disk induction and exhaust port present in the carter of a two-stroke engine.
• the resilient ring fitted around the perimeter of the gas port through the carter's wall of a two-stroke engine improves the sealing conditions during particularly burdensome condition of operation and reduces the wear on the sealing face of the rotating disk shutter.
• Figure 1 is a schematic cross section of a cylinder of a four-stroke engine having the intake and exhaust devices of the invention;
• Figure 2 is a detail view showing the induction and exhaust port;
• Figure 3 is a schematic view of a rotating disk shutter of the device of the invention.
• Figure 4, 5, 6 and 7 show in detail several alternative configurations of the sealing ring surrounding the port and cooperating with the rotating disk shutter.
• an engine's the cylinder is substantially defined by a rectified hole of a steel body 1, into which runs the piston 2, linked by a pin 3 to one end of the rod 4.
• the two orifices 5 and 6 may be identical or different from each other; each may have a shape and a cross sectional area that may be freely optimized during the design, in function of other geometric parameters of the cylinder, that is, of the combustion chamber.
• the orifices 5 and 6 may be shaped as illustrated in Fig. 2.
• the port area of the orifices 5 and 6 may be identical or different depending on design volumes, mixing and compression ratios.
• annular channel or groove 7 On a flattened portion around each of two orifices 5 and 6, of the outer surface of the body 1 of the cylinder there is an annular channel or groove 7 around the orifice.
• the groove accommodates a sealing ring 8 that surround the port's perimeter, as shown in Fig. 2.
• the sealing ring 8 protrudes for a certain height from the plane of the flattened surface and is elastically compressible by the face of a rotating disk shutter 9, both for the intake port 5 and the exhaust port 6.
• Each rotating disk shutter 9 has a window 10 in the form of a circular sector, whose shape and size may be optimized in the design stage, as indicated in Fig. 3.
• Each rotating shutter is mounted on its own shaft 11 , supported on a first bearing 12 fitted in the wall 1 of the cylinder and on a second thrust bearing 13 fitted in an outer case 14 of the engine, having internal channels 15 to allow for the circulation of a cooling liquid.
• Each of the two half-shells that compose the engine's body 14 defines a casing 16 which confines the relative rotating disk shutters and has orifices or passage apertures 17 and 18, geometrically coordinated with the apertures ports 5 and 6, through which the intake and exhaust gases pass.
• each half-shell 16 of the engine body 14 limits possible deflections of the rotating disk shutter that may accidentally occur during the combustion and expansion phases of the gases inside the cylinder's chamber.
• the surface of the casings 16 that confines the disk shutters 9 may have one or more inserts, preferably circular and concentric to the disk shaft made of a suitable wear resistant anti friction material such as a bronze, on the surface of which the rotating disk shutter 9 may momentarily abut during the combustion and expansion phases.
• the rotating disk shutters 9 are made of a high strength and high elasticity material, capable to regain their straightness when abnormally high pressure conditions inside the combustion chamber of the cylinder are relieved.
• the piston 2 may completely or partly cover the induction and exhaust ports 5 and 6, upon reaching the highest point of the travel.
• the oil scraper ring or rings 19 of the piston 2 should not reach and surpass the bottom edge of the induction and exhaust apertures 5 and 6, in order to prevent oil to enter the intake and exhaust ducts.
• the scraper ring may be installed under the pin of the piston.
• the sealing ring 8, elastically abutting against the face of the disk shutter may be realized in different ways, some of which are schematically illustrated in Figures 4 to 7.
• the sealing ring 8 is elastically pushed and held in contact with the face of the rotating disk shutter 9 by a plurality of coil springs 20, placed at the bottom of the annular channel 7 at spaced positions along the channel.
• the resilient element is an elastomer ring 21 capable to withstand the temperatures that may be reached on the outer surface of the cylinders.
• Fig. 6 shows another alternative embodiment based on the use of a circular truncated-cone spring washer 22
• Fig. 7 depicts another solution wherein the sealing ring 8 and the housing channel 7 have inclined surfaces (trapezoidal sections) of abutment with each other while the resilience in this case is given by the elasticity of the ring 8 itself which, according to this embodiment is not continuous but has a cut, the opposite faces of which are parallel to each other and preferably inclined, defining a certain gap therebetween, in order to permit an elastic contraction and expansion of the seal ring.
• the functional parts of the sealing device of the invention that is, the rotating disk shutter, the sealing ring 8, the resilient element 20, 21, 22, as well as the antifriction antiwear inserts that optionally may be installed on the contrasting surface of the outer casing 16 that confines the rotating disk 9, are realized with mechanical materials having adequate elastic and antiwear characteristics capable to endure the temperatures of operation of the engine, according to normal design considerations.
• the rotating disks and the relative sealing rings may be of steel, cast iron, light-weight alloys, eventually coated with chromium, with a cermet and/or a ceramic material in order to enhance wear resistance.
• the antifriction inserts that may optionally exist on the disk deflection contrasting surface of the outer casing of the engine, may be circular sectors or rings made of bronze, steel or a light-weight alloy, solidly inserted in cavities of the inner surface of the casing.
• the head of the engine's cylinders may be optimally configured without any restraining consideration for the realization of common induction and exhaust valves therethrough.
• the overall vertical encumbrance of the engine may be minimized because the transmissions for operating the induction and exhaust valves may be disposed sideways of the cylinders as easily recognized.

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• Engineering & Computer Science (AREA)
• Mechanical Engineering (AREA)
• General Engineering & Computer Science (AREA)
• Valve Device For Special Equipments (AREA)
• Characterised By The Charging Evacuation (AREA)

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Publications (1)

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Cited By (2)

Citations (5)

• 1998
  • 1998-04-23 IT IT98VA000007 patent/IT1305638B1/it active
• 1999
  • 1999-04-22 WO PCT/IT1999/000102 patent/WO1999054600A1/en active Application Filing

Patent Citations (5)

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