Classifications

• • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
  • F01—MACHINES OR ENGINES IN GENERAL; ENGINE PLANTS IN GENERAL; STEAM ENGINES
  • F01B—MACHINES OR ENGINES, IN GENERAL OR OF POSITIVE-DISPLACEMENT TYPE, e.g. STEAM ENGINES
  • F01B3/00—Reciprocating-piston machines or engines with cylinder axes coaxial with, or parallel or inclined to, main shaft axis
  • F01B3/02—Reciprocating-piston machines or engines with cylinder axes coaxial with, or parallel or inclined to, main shaft axis with wobble-plate
• • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
  • F01—MACHINES OR ENGINES IN GENERAL; ENGINE PLANTS IN GENERAL; STEAM ENGINES
  • F01B—MACHINES OR ENGINES, IN GENERAL OR OF POSITIVE-DISPLACEMENT TYPE, e.g. STEAM ENGINES
  • F01B3/00—Reciprocating-piston machines or engines with cylinder axes coaxial with, or parallel or inclined to, main shaft axis
  • F01B3/0002—Reciprocating-piston machines or engines with cylinder axes coaxial with, or parallel or inclined to, main shaft axis having stationary cylinders
• • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
  • F01—MACHINES OR ENGINES IN GENERAL; ENGINE PLANTS IN GENERAL; STEAM ENGINES
  • F01B—MACHINES OR ENGINES, IN GENERAL OR OF POSITIVE-DISPLACEMENT TYPE, e.g. STEAM ENGINES
  • F01B3/00—Reciprocating-piston machines or engines with cylinder axes coaxial with, or parallel or inclined to, main shaft axis
  • F01B3/10—Control of working-fluid admission or discharge peculiar thereto
  • F01B3/101—Control of working-fluid admission or discharge peculiar thereto for machines with stationary cylinders
• • 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
• • 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
  • F02B75/16—Engines characterised by number of cylinders, e.g. single-cylinder engines
  • F02B75/18—Multi-cylinder engines
  • F02B2075/1804—Number of cylinders
  • F02B2075/1828—Number of cylinders seven

Definitions

• the invention relates to a multicylinder engine with the cylinders disposed in a circle and parallel to the centre line C/L, to assume the so-called barrel-type configuration, wherein the pistons are mounted and supported by a wobbling mechanism.
• Said mechanism is conceived to reversibly convert the reciprocating movement of the multiplicity of pistons (disposed in a circular row), into the rotation of a crankshaft around the C/L, and for reversibly convert at the same time, the forces insisting on said pistons, into a corresponding couple insisting on the same central crankshaft.
• the wobbling unit which from now on will be referred to as "the wobbling unit” and abbreviated in WU, is essentially determined by two types of constraints: a) - an axial constraint, formed by supporting bearings mounted on a tilted shaft portion of a generally Z-shaped main crankshaft, whereby the axis (w-w) of the WU is bound to form a fixed angle ⁇ with the axis (C/L) of the crankshaft, thus describing a circular double- cone having as aperture angle the angle ⁇ (corresponding to the tilt angle of the shaft portion with respect to the axis of the main crankshaft) and having its vertex coinciding with the central point O of the spherical movement; b) - an angular constraint against the rotation around its own axis, determined by the meshing of a bevel gear (m), having an aperture of 180°- ⁇ /2, integrated to the WU, over an identical bevel gear (n), symmetrically
• said angular constraint can alternatively, but less efficiently, be obtained by means of a spherical coupling and a cardan joint between the wobbling element and the casing of the mechanism, as illustrated by the known mechanisms of D1 and D 5.
• Another object of the invention is to select the value of certain geometrical parameters of the wobbling unity, in particular the tilt angle ⁇ ⁇ 10°, such as to minimise the lateral displacement of the piston, and optimise the space availability for the cylinders in the circular row, in relation to the piston's stroke. Another object is to minimise the friction forces around the piston. This is achieved by fixedly mounting the pistons on the wobbling unit so as to form a single solid piston unit.
• Another object is to alleviate the torsional stresses on the crankshaft and the cyclic forces on the crankshaft bearings (against the wobble unit and against the casing) so as to allow an overall lighter structure and the lower level of vibrations.
• This is achieved by providing a further couple of bevel gears having the vertex of their primitive cones coinciding with the centre point O of the mechanism.
• Another object is to shape the internal rotating ducts of the distributor ring so as to generate a pre-compression of the operating fluid at the entrance of the cylinders.
• Figure 1 is a vertical axial section of an internal combustion engine according to a preferred embodiment of the invention.
• Figure 2 represents the vectorial diagram governing the cinematic parameters of the wobbling movement in relation to the rotating parts of the engine.
• Figure 3 is a perspective view of a type of distributor ring, featuring 5 sectors and adapted to govern the 9-cylinder engine of figure 1.
• Figure 4 is a schematic perspective representation of the 9-cylinders engine main body, which can be mated with fluid distributor ring of Figure 3.
• Figure 5 is a perspective representation of a partially cut-away engine according to the configuration of figure 1.
• Figure 6 represents an axial section of a three-dimensional model capable of physically demonstrating the dynamic valve function of the distributor ring, by its synchronic rotating versus the pistons strokes.
• Figure 7 comprises 8 schemes (Fig.7a to 7h) which reproduce a 7-piston- engine axial-cylindrical sections, developed on a plane, taken at the radial level of the cylinder ports and at 8 different points in time (like photo shuts), all spaced a part by a regular time interval ⁇ T, during one complete 4-stroke cycle.
• Figure 8 is an over-view and a cylindrical section of a cylinder-head's port provided with one possible type of sealing (against the distributor ring).
• Figure 9 represents the classic Diesel (full line) and Otto (dash line) thermodynamic cycles in a p/v plane, along a 4-stroke cycle.
• Figure 10 represents the same cycles of fig. 9 but on a T/S plane, with the assumption of an ideal gas working in frictionless and pure adiabatic conditions.
• Figure 11 similar cycles as above, on a p/v plane, with additional dashed lines and area to represent a double expansion phase along an 8-stroke cycle.
• Figure 12 thermo-dynamical cycles as above, on a T/S plane, with additional dashed areas to represent a double compression phase and a double expansion phase, along a 12 stroke cycle.
• Figure 13 is a bottom view, completed by a circular elevation section (A-A) of one sector (A) of a distributor ring adapted for a 4-stroke cycle to be operated in a 7-cylinder engine.
• Figure 14 comprises a horizontal section (A - A) and a radial elevation section (B - B) of one sector (A) of a distributor ring adapted for an 8-stroke cycle to be operated in a 7-cylinder engine.
• FIGS. 1 to 5 show a first embodiment of the claimed internal combustion engine whose general layout is formed by a plurality of combustion chambers 11 or cylinders assembled together in a circular row over an essentially circular casing 12 with their axis generally parallel to the centre line (C/L) of the casing, i.e. of the engine.
• Such a layout authorises the conventional denomination of "Barrel Engine”.
• a corresponding plurality of pistons 13 are able to move up and down in a sealed contact, so as to generate a displacement volume, the pistons being supported and connected, through their stems, to the peripheral edge 14 of a wobbling unit 15 (WU), which is in turn rotatably supported, through bearings (not shown), by a Z-shaped crankshaft 16.
• This crankshaft is mounted on the casing, through other bearings (not shown), in order to rotate around said C/L.
• the present engine comprises an uneven number of cylinders: this is a necessary condition in order to allow the synchronisation with a rotary distributor 23 which governs the admission and exhaust of the operative fluid into and from each combustion chamber, as later on further explained.
• Said rotary distributor is formed by a solid ring composed by a number S of identical circular sectors, see figure 3, each sectors comprising one admission opening (Aa, ..., Ea) and one exhaust opening (Ae, ..., Ee), as well as relevant ducts 24, 25 leading to corresponding admission and exhaust external openings which communicate with an admission collector and an exhaust collector respectively.
• Said ring is rotatably mounted around and perpendicular to the C/L of the engine, directly over the heads of the cylinders in a sliding contact therewith so that the each of said openings is progressively brought into register with a single hole or port (P1, ... , P9) provided in the cylinder heads, thereby said ring functioning as admission and alternatively exhaust valves, contemporary over all the cylinder heads with a cyclic frequency equal to ⁇ M /2, as it is necessary for controlling the well known four-stroke thermodynamic cycle of the internal combustion engines.
• the sector B is now ready to take over the distribution on the cylinder n° 1 , for the following cycle.
• FIG 13 another more detailed example of a single sector is given, as part of a four-sectors distributor ring adapted to govern a 4-stroke cycle on a 7 cylinder engine.
• thermodynamic cycles characterised by a higher number of piston strokes, e.g. : a 6-stroke or in a 8-stroke or even in a 12-stroke cycle. This will become apparent by following this reasoning:
• the number of cylinder N must be odd (for the reason of synchronisation) but also N+1 must be a multiple of 4.
• the ring is formed by two sectors, only the sector A being completely drawn with full lines, and sector B is drawn with dash lines. They are however identical and provided each with six ports, in specific angular positions, which allow the correct control of the gas flow in-and-out flow with a synchronic sequence, parallel to that explained in relation to figure 13, but extended to the case of the 8-stroke cycle. Further aspects on this example will be discussed later on.
• thermodynamic nature and associated advantages of a 6- or 8-or 12-stroke cycle is unknown in the state of the art, at least within the field of the volume- displacement engines, having the classic multi-cylinder V or in-line configuration, supposedly because considered too complex and impracticable to realize, so as to leave them unexplored. Instead, it has been found, analysing the present barrel engine configuration, that very useful applications can be accomplished, taking advantage of the above multi- stroke cycles capability, and still maintaining a very simple mechanical layout. Contrary to the 6-stroke cycle, which does not appear to find any useful application, the 8-stroke and the 12 stroke cycles, have shown to be of particular interest, as will be soon explained.
• the three main phases of these "open" cycles are shown by the lines 1-2, 2-3 and 3-4, which indicate the adiabatic compression phase, the heat supply phase (combustion by spark ignition or by progressive injection) and the adiabatic expansion phase, respectively.
• the line 4-1 conventionally represents the "heat extraction” phase which takes place externally of the engine, since notoriously the "open cycles” start with fresh gas (air) sucked from atmosphere (at the conditions of point 1) and terminates with expanded gas discharged into atmosphere (at the conditions of point 4). It is known how the area internal to the diagram of figure 9 represents the "Work" transformed into mechanical energy by the engine during every cycle. Similarly in figure 10, i.e.
• the relevant chamber's openings are located in a determined order and angular positions, among the positions of the admission openings Aa, Ba and of the exhaust openings Ae, Be in such a way that said toroidal expansion chamber enters in communication with the various cylinders, as the ring slides over them, during predetermined time intervals coinciding with the appropriate time phases of the 6-phases thermodynamic cycle illustrated in figure 11.
• IPCC intermediate pressure compression chamber
• Said compression chamber is also provided with three extensions (24',24" ) 24"'), for each sector, which open into said bottom circular surface 23' of the ring, at an appropriate angular position to allow the compressed gas flow to enter and leave the cylinders during the first six strokes of each piston, in phase with the following six strokes (total 12-stroke) which are then responsible for the double expansion phase, as already explained above, with the figure 13, in the case of a 6 phase thermodynamic cycle.
• this additional IPCC compression chamber is enabled to transfer the fluid, compressed to an intermediate pressure, from one cylinder to two cylinders which are diametrically opposed within the cylinders circular row of the barrel engine, whereby the compression chamber performs also the function of a buffer for the intermediately compressed fluid.
• the resulting "double compression phase” is represented by the lines between the points 1 and 2' (first compression) and 2"-2 (second compression) in figure 12.
• the static equatorial plane E is the virtual plane in sympathy with the casing of the mechanism, perpendicularto its C/L and containing the centre point O of the spherical movement.
• the mobile equatorial plane W is the virtual plane in sympathy with the moving wobbling unit, perpendicular to the axis (w-w) of the same unit and also passing through the centre point O of the mechanism.
• c) - The equatorial straight line R is the intersecting virtual line of the planes E and W, which also goes through the centre point O.
• IWU integral wobbling unit
• a wobbling unit which integrally incorporates also the pistons see the schematic design in Figs 1 and 5
• the heads of the piston are sensibly disposed at the level of the plane W of the wobbling unit
• the sealing function between pistons and cylinders can be relied upon simple circular segments carried, in a floating but tight contact, by the lateral surface of the pistons.
• the sealing problem reveal itself to be technologically critical and/or not sufficiently effective, the problem can be relaxed by providing a swivel joint at the foot of the piston rod, instead of a fixed connection, for example, by means of a rod-end-bearing.
• a further preferable characteristic is formed by a second couple of bevel gears, the vertex of which is also placed at the centre O of the engine.
• the duty of said bevel gears is that of taking the torque (thus the power) out of the wobbling unit and transmitting it to an output shaft co-axial, but distinct from the main engine shaft.
• the cited torque is that generated by the cyclic succession of forces exerted by the pistons in their expansion strokes all around the periphery of the wobbling unit.
• the first (28) of these bevel gear is an internal bevel gear mounted under the bottom of the wobbling unit and it meshes progressively over a second external bevel gear or conical pinion (29) which is rotatably supported by the casing (see figure 1 ) around the centreline C/L of the engine and coupled to the output shaft of the engine.
• This first internal gear 28, fixedly and co-axially mounted to the WU (15), has a primitive cone with an angle ⁇ at its vertex, said vertex being placed on the centre point O, and the second (external) pinion gear (29), rotatably mounted around the C/L on the bottom part of casing (12), has a primitive cone with an angle ⁇ at its vertex which coincide with the vertex of the first gear (28) on the centre point O of the engine so that the are in an appropriate meshing condition, during the wobbling movement of the WU.
• ⁇ P ⁇ M is a desired value of a reductive transmission ratio between the wobbling frequency, i.e. the main-shaft rotary speed: ⁇ M , and the pinion's (29), i.e. the engine-output-shaft's, rotary speed: ⁇ P .
• said second couple of bevel gears (28, 29) is adapted to extract the forces, generated by the pistons, out of the WU and to transform them into a couple on the axis of the pinion, i.e. onto the output-shaft (30) of the engine, advantageously discharging the engine's main crank-shaft (17+19+21) from all torque stresses.
• the main shaft is substantially if not totally relieved from the torque stresses and from all sorts of torsional vibrations which represent a major problem in the classic crankshaft of multi-cylinders engines.
• the wobble unit can be considered as a three-dimensional structure which is far more rigid compared to the mono-dimensional structure of the classic crankshaft.
• the WU can support and integrate the internal stresses much more efficiently and can smooth out all sources of vibrations. Moreover, considering the absence of centrifugal forces in the pistons and in the WU it is predictable that such a three-dimensional structure can accept a very high rotational regime with a comparatively lower stress and vibrational levels, so as to allow a considerably lighter design with a consequent saving in the overall weight of the engine. Thus, the engine of the invention can be expected to reach much higher rotational speed than the conventional engines d)
• the perfect angular symmetry of the configuration allows for a modular construction, with a basic angular sector or module spanning an angle of 360°/N each representing a cylinder. This simplify the manufacture and the assembly of the engine.

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• Engineering & Computer Science (AREA)
• Mechanical Engineering (AREA)
• General Engineering & Computer Science (AREA)
• Chemical & Material Sciences (AREA)
• Combustion & Propulsion (AREA)
• Cylinder Crankcases Of Internal Combustion Engines (AREA)
• Shafts, Cranks, Connecting Bars, And Related Bearings (AREA)
• Valve Device For Special Equipments (AREA)

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• 2004
  • 2004-07-14 DE DE602004024082T patent/DE602004024082D1/de not_active Expired - Lifetime
  • 2004-07-14 EP EP04766214A patent/EP1658417B1/fr not_active Expired - Lifetime
  • 2004-07-14 WO PCT/EP2004/051484 patent/WO2005012692A1/fr active Application Filing
  • 2004-07-14 AT AT04766214T patent/ATE448385T1/de not_active IP Right Cessation

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