EP1503049A1

EP1503049A1 - Internal combustion engine with rotary slide valve

Info

Publication number: EP1503049A1
Application number: EP03425516A
Authority: EP
Inventors: Mario Brighigna; Edoardo Ruggiero
Original assignee: Individual
Current assignee: Individual
Priority date: 2003-07-31
Filing date: 2003-07-31
Publication date: 2005-02-02

Abstract

The reciprocating internal combustion engine (1) basically comprises a cylinder block (2), two modular units (3) which can be slidably housed in a sealed fashion each inside a respective cavity (13) in the cylinder block (2), and a rotary distributor (4) rotatably housed in a sealed fashion in a cylindrical hole (21) made, for each unit (3), in a head (16) of the unit (3).

Description

The present invention relates to an internal combustion engine with rotary distribution.
In particular, the present invention relates to a reciprocating engine with a rotary device for distribution of the exhaust and intake gases.
In the sector of reciprocating internal combustion engines, use is known of rotary distributors in place of normal distributor devices which use poppet valves located in the cylinder head and moved alternately by a camshaft, directly or by means of suitable intermediate elements such as rocker arms.
The objectives which such rotary distributors intend to fulfil are many but substantially all linked to the idea of simplifying and improving on the above-mentioned devices which use poppet valves.
In recent years prior art has shown the possibility that using rotary valves allows current limits on silence and the number of revolutions of internal combustion engines to be exceeded, both for those using the Otto cycle and those with a Diesel cycle, their limits being caused, at least in part, by the structure of the current intake and exhaust poppet valves.
Due to their reciprocating motion with elastic return, the speed of poppet valves is inevitably constrained by the mechanical characteristics of the elastic element which activates them and, moreover, they produce a metal impact at the end of each stroke, with a consequent high noise level.
In contrast, rotary valves may reach a high speed of rotation and are extremely silent since there are neither elastic elements for the return strokes, nor metal impacts at the end of each stroke.
However, on the other hand, rotary valves are problematic as regards a fluid seal.
The existence of a good seal is essential for correct engine operation, since a loss of pressure in the combustion chamber results in a loss of power and poor engine operation.
The problem of the seal has been partially solved by adopting an engine structure which basically consists of a cylinder block, one or more cylindrical bodies which can be slidably housed in respective holes in the cylinder block and a rotary distributor rotatably housed in a sealed fashion in a continuous hole made both in the walls of the cylinder block and in the cylindrical bodies so as to act as an assembly element for them. The solution described above improves the seal because it increased proportionally to increases in the pressure in the axial holes of the cylindrical bodies, that is to say, in the combustion chambers. Despite this, following experimental testing, the solution described above did not proved entirely satisfactory.
Problems linked to the use of rotary distribution which have not yet been suitably solved consist of cooling rotary distributor components and lubricating them, as well as the poor strength of the distributor.
The rotary distributor normally consists of a drum opposite the cylinder combustion chambers, through which hot exhaust gases pass, and rotating inside a special housing at very high speed. These characteristics contribute to heating up the distributor, exposing it to the risk of thermal deformation and consequent dangerous malfunctions.
The aim of the present invention is to provide an internal combustion engine with rotary distribution with an improved fluid seal, rotary distributor lubrication and cooling and mechanical strength, which can overcome the above-mentioned problems and disadvantages.
These and other aims, more clearly illustrated in the description which follows, are achieved by an internal combustion engine with rotary distribution as described in the claims herein.
The technical features of the present invention, in accordance with the above-mentioned aims, are set out in the claims herein and the advantages more clearly illustrated in the detailed description which follows, with reference to the accompanying drawings, which illustrate a preferred embodiment without limiting the scope of application, and in which:

Figure 1 is a schematic longitudinal section with some non-essential parts cut away, of an engine made in accordance with the present invention;
Figure 2 is a schematic cross-section according to the line II - II illustrated in Figure 1;
Figure 3 is a cross-section according to the line III - III illustrated in Figure 1, with some parts cut away to better illustrate other;
Figure 4 illustrates the detail from Figure 3, in cross-section according to the line IV - IV illustrated in Figure 3;
Figure 5 is a schematic perspective view of the detail illustrated in Figures 3 and 4;
Figure 6 is an enlarged view of the detail P illustrated in Figure 1;
Figure 7 is a cross-section according to the line VII - VII illustrated in Figure 1, with some parts cut away to better illustrate others;
Figure 8 is a schematic longitudinal section with some non-essential parts cut away, of an alternative embodiment of the engine illustrated in Figure 1.

With reference to Figure 1, the reciprocating internal combustion engine disclosed, labelled 1 as a whole, comprises a cylinder block 2, two modular units 3 and a rotary distributor 4.
In Figure 1, the engine 1 is represented as being of the four-stroke type, with two in-line cylinders. This configuration is used by way of example only and in no way limits the many possible different configurations of the engine made in accordance with the present invention.
As illustrated in Figure 1, the cylinder block 2 comprises a base wall 5 and three vertical walls 6, 7, 8 extending from the base wall 5.
In a lower zone 9, the cylinder block 2 comprises a chamber 10 which houses a crankshaft 11 with an axis of rotation A.
In a central zone 12 of the cylinder block 2, the vertical walls 6, 7, 8 of the cylinder block 2 form two substantially cylindrical cavities 13 extending from the chamber 10 and having respective central axes B, parallel with one another and perpendicular to the axis of rotation A of the crankshaft 11. The crankshaft 11 passes through the two cavities 13 and is supported, by means of bearings of the known type, by the walls 6, 7 and 8 of the cylinder block 2.
The cavities 13 comprise respective lower ends 13a, opposite the chamber 10, and upper ends 13b, longitudinally opposite according to the central axis B.
At an upper zone 14 of the cylinder block 2, close to the upper ends 13b of the cavities 13, on the walls 6, 8, there are two circular holes 15, coaxial with one another and arranged with the axis parallel with the axis B of the crankshaft 11.
Each modular unit 3 comprises a head 16 and a cylindrical body 17, connected to the head 16 and inserted, so that it slides axially, in one of the cavities 13 in the cylinder block 2, coaxial with the cavity.
The cylindrical body 17 is advantageously connected to the head 16 by forced screwing down.
The cylindrical body 17 has an internal cylindrical wall 18 extending from the head 16 and, at the bottom, leading into the chamber 10 of the cylinder block 2.
The cylindrical wall 18 of each modular unit 3 houses, sealed and axially sliding, a piston 19 kinematically connected to the crankshaft 11, in the known way and using methods that are also known and, therefore, not described in further detail. The cylindrical wall 18 of each modular unit 3 forms a combustion chamber 20 between the head 16 and the piston 19.
Through each head 16 there passes, transversally to the axis of the cylindrical body 17, a cylindrical hole 21 made in alignment with the circular holes 15. The different heads 16 are aligned with one another in succession in such a way that the respective cylindrical holes 21 are coaxial with one another. As is better illustrated in Figure 3, each of the holes 21 has its own internal cylindrical surface 22.
The hole 21 in the head 16 is in communication with one or more exhaust and/or intake ducts 23, 24 leading to the outside of the head 16 and, through respective ports 25 and 26, in communication with the combustion chamber 20. The number of ducts 23, 24 for each head 16 substantially depends on the type of engine to be made. For two-stroke engines there is only one exhaust duct 23, whilst four-stroke engines, like the one illustrated in the accompanying drawings, have two ducts, respectively one intake 24 and one exhaust 23.
Through the head 16 there also pass one or more holes, not illustrated, extending from the outside of the head towards the combustion chamber 20, housing a part for ignition or for the supply of a mixture fed into or to be fed into the combustion chamber 20.
Again with reference to Figure 1, the rotary distributor 4 is cylindrical and is housed in the cylindrical holes 21 in the heads 16, supported, in such a way that it can rotate freely, by two radial bearings 27 and 29. The rotary distributor 4 has its own axis of rotation C.
The above-mentioned radial bearings 27 and 29 are inserted in respective housings 30, 32 formed by the above-mentioned holes 15, made in the vertical walls 6, 8 of the cylinder block 2.
With reference to Figure 7, in a lower zone of their internal face, each of the bearings 27, 29 has a recess 100 forming a zone 101 for accumulation of a lubricating fluid. As illustrated in Figure 7, the recess 100 extends along the circumference for an angle β less than 180°.
As is clearly illustrated in Figure 1, the rotary distributor 4 constitutes an assembly element between the modular units 3 and the cylinder block 2 since, once inserted in the respective holes 15 and 21, it prevents them from being separated from one another. The dimensions of the holes 15 and 21 therefore differ only in terms of the presence, at the holes 15, of the bearings 27, 29 supporting the rotary distributor 4. The bearings 27 and 29 are advantageously of the plain type or brasses or, in alternative embodiments not illustrated, of the rolling bearing type.
The rotary distributor 4 has a substantially cylindrical external side surface 33 and a plurality of transversal through-openings 34, distributed axially along the axis C and designed to allow communication between the ports 25 and 26 of each head 16 and the respective exhaust and intake ducts 23 and 24. In the case illustrated in the accompanying drawings, the openings 34 are diametric through-openings and the ports 25, 26 are, therefore, diametrically opposed to the ducts 23, 24, relative to the rotary distributor 4.
However, obviously, this is only one embodiment given by way of example and does not limit other possible embodiments in which the ducts 23, 24 are in other positions relative to the ports 25, 26 and the openings 34 do not extend in a diametric straight line.
In the embodiment illustrated in the accompanying drawings, the external side surface 33 of the distributor 4 is formed by a cylindrical covering liner 102, made of metal material with high strength and hardness.
In alternative embodiments not illustrated, the liner 102 is made of ceramic material.
In other alternative embodiments not illustrated and using an alternative to the covering liner, the external side surface 33 of the distributor 4 is hardened using heat treatments on the surface of the distributor 4.
The rotary distributor 4 is kinematically connected to the crankshaft 11 by a toothed belt 35, as illustrated in Figure 1. In this way, the distributor is rotated in such a way that it is synchronised with the rotation of the crankshaft 11. The gear ratio between the crankshaft 11 and the rotary distributor 4 is, with reference to the case illustrated for a four-stroke engine, 1/4.
As illustrated in Figures 1, 6 and 8, on its external side surface 33, the rotary distributor 4 has a plurality of circular radial seal segments 36, housed in respective circular recesses 37 made in the liner 102 and inserted between the distributor 4 and the internal cylindrical surfaces 22 of the holes 21. The details of the segments 36 and recesses 37 are clearly illustrated in Figure 6 which is an enlarged view of the detail P illustrated in Figure 1.
For each transversal opening 34, two circular recesses 37 are made respectively upstream and downstream of the opening relative to the axis C of the rotary distributor 4, to house relative seal segments 36.
As is schematically illustrated in Figure 1, the engine 1 comprises a pump 38 for the lubricating fluid, located in a special housing 38a made in the vertical wall 6 of the cylinder block 2. From the pump 38 there extends a lubricating duct 39, a first portion 39a of which supplies the pressurised lubricating fluid to the bearing 27 which supports the rotary distributor 4.
As illustrated in Figure 7, through the bearing 27 wall thickness, the first portion 39a leads into the recess 100 forming the zone 101 for accumulation of the lubricating fluid.
At the bearing 27, the distributor 4 has a first radial channel 40, designed to allow fluid communication between the first portion 39a of the lubricating duct 39 and the second portion 39b of the duct 39. The second portion 39b is inside the rotary distributor 4 and extends longitudinally according to the distributor axis C.
With reference to Figure 1, further channels 40 are visible at the bearing 29. Through these channels 40 the lubricating fluid in the second portion 39b of the duct 39, driven both by the pressure applied to it by the pump 38 and the centrifugal force to which it is subject following rotation of the distributor 4, flows towards the bearings 29.
The lubricating duct 39 also comprises a third portion 39c, extending from the bearing 29 and connected to the chamber 10 housing the crankshaft 11. The lubricating fluid supplied to the bearing 29 flows through the third portion 39c of the duct 39 and into the chamber 10 from which it is drawn again by the pump 38 and again circulated in the duct 39, according to known methods, not described in further detail herein.
As illustrated in Figures 4 and 5, on the internal cylindrical surface 22 of the hole 21 there is a longitudinal groove 41 extending parallel with the axis C and with the generatrices of the cylindrical hole 21. A plurality of second channels 42 lead onto the internal surface 22 of the cylindrical hole 11 at the groove 41, to draw the lubricating fluid from the surface 22. The second channels 42 are arranged in succession along the groove 41.
Each channel 42 is connected, in a way not illustrated, to the lubricating duct 39 and to a vacuum part 103 located outside the vertical wall 6, at one end of the distributor 4. The vacuum part 103 is of the type with vanes, commonly used in the automobile sector.
In other words, the vacuum part 103 draws the lubricating fluid through the channel 42 and returns it to the duct 39.
The pump 38, duct 39 with its portions 39a, 39b and 39c, first channels 40, second channels 42, groove 41 and vacuum part 103 together form lubricating means 43 for the engine 1 and, in particular, for the rotary distributor 4.
Moreover, the engine 1 comprises a duct 44 for cooling the rotary distributor 4 designed to supply the distributor 4 with a cooling fluid. In the embodiment illustrated in the accompanying drawings, the cooling duct 44 is also the lubricating duct 39, meaning that the cooling fluid is also the lubricating fluid.
The cooling duct 44 forms, for the engine 1, cooling means 45, in particular for cooling the rotary distributor 4.
Advantageously, the channels 40 connected to the bearing 29 are connected, in a way not illustrated, to the vacuum part 103 which promotes the return of the lubricating fluid accumulated at the bearing 29 to the chamber 10 then towards the pump 38 again.
In other words, the suction action of the vacuum part 103 guarantees constant limitation of the accumulation of lubricating fluid on the internal surface 22, preventing excess lubricating fluid from being drawn up by the vacuum produced in the combustion chamber 20 during the piston expansion stage.
In alternative embodiments of the present invention, not illustrated, the above-mentioned cooling duct 44 is separate from the lubricating duct 39 but still partially extends inside the rotary distributor 4. Similarly, the cooling fluid may be separate from the lubricating fluid.
As illustrated in Figures 1 and 2, the engine 1 also comprises, for each modular unit 3, a ring-shaped cavity 48 substantially coaxial with the cylindrical body 17, the cavity 48 being in fluid connection with the cooling duct 44 so as to carry away from the cylindrical body 17 the heat produced in the combustion chamber 20 during normal engine 1 operation.
Advantageously, by means of the characteristics described above, the engine 1 disclosed allows effective lubrication of the rotary distributor 4 as well as equally effective distributor cooling.
In the case of an engine with two-stroke configuration, the engine 1 differs from the above description referring to the four-stroke configuration only in terms of the presence of an intake chamber, not illustrated, at the side of the cylindrical body 17, and the presence, inside the cylindrical body 17, of a plurality of intake ports left open by the piston 19 when it reaches its bottom dead centre.
In the embodiment illustrated in Figure 8, the engine disclosed comprises four modular units 3 arranged in line alongside one another with a single rotary distributor 4 passing through them. Therefore, advantageously, the engine disclosed allows the modular assembly of various numbers of units 3, starting with a single unit 3, guaranteeing maximum versatility and flexibility during the design stage.
The invention described can be subject to numerous modifications and variations without thereby departing from the scope of the inventive concept. Moreover, all the details of the invention may be substituted by technically equivalent elements.

Claims

An internal combustion engine with rotary distribution, comprising:

a cylinder block (2) with at least one cavity (13) for housing at least one respective cylindrical body (17) designed to house a piston (19) that slides in a sealed manner;

a head (16) connected to the cylinder block (2) at one end (13b) of the cavity (13) and having a cylindrical hole (21) perpendicular to the cylindrical body (17), the cylindrical body (17) and the hole (21) in the head (16) communicating with one another by means of at least one first port (25, 26);

a cylindrical rotary distributor (4) housed in such a way that it rotates freely in the hole (21) in the head (16), the distributor (4) having at least one transversal through-opening (34) designed to allow cyclical communication between the port (25, 26) and an exhaust or intake duct (23, 24) extending from the head (16), the engine being characterised in that it comprises at least one pair of circular radial seal segments (36), inserted between the cylindrical distributor (4) and the cylindrical hole (21) and arranged axially, respectively upstream and downstream of the transversal opening (34) in the cylindrical distributor (4).
The engine according to claim 1, characterised in that it comprises, on a side surface (33) of the cylindrical distributor (4), circular recesses (37) for housing the circular radial seal segments (36).
The engine according to claim 2, characterised in that the distributor (4) comprises an external cylindrical covering liner (102) made of a very strong material, the liner (102) forming the side surface (33).
The engine according to claim 3, characterised in that the external cylindrical covering liner (102) is made of steel.
The engine according to claim 3, characterised in that the external cylindrical covering liner (102) is made of ceramic material.
The engine according to any of the foregoing claims from 1 to 5, characterised in that it comprises lubricating means (43) designed to facilitate rotation of the cylindrical distributor (4).
The engine according to claim 6, in which the cylindrical distributor (4) is supported by at least two radial bearings (27, 29) inserted in respective housings (30, 32) integral with the cylinder block (2), characterised in that the lubricating means (43) comprise a lubricating duct (39) designed to supply lubricating fluid to the radial bearings (27, 29).
The engine according to claim 7, characterised in that each of the bearings (27, 29) comprises a zone (101) for at least temporary accumulation of the lubricating fluid.
The engine according to claim 8, characterised in that the zone (101) for accumulation of the lubricating fluid comprises a recess (100) made in an internal face of the bearing (27, 29).
The engine according to any of the foregoing claims from 7 to 9, characterised in that the lubricating duct (39) extends at least partially inside the cylindrical distributor (4) and, for each radial bearing (27, 29), comprises a channel (40) connected to the bearing (27, 29).
The engine according to claims 9 and 10, characterised in that the channel (40) leads into the zone (101) for accumulation of the lubricating fluid.
The engine according to any of the foregoing claims from 6 to 11, characterised in that the lubricating means (43) comprise at least one groove (41) made in the internal surface (22) of the cylindrical hole (21), the groove (41) being designed to distribute the lubricating fluid on an external surface (33) of the cylindrical distributor (4) during rotation of the distributor.
The engine according to claim 12, characterised in that the groove (41) extends longitudinally parallel with the generatrices of the cylindrical hole (21).
The engine according to either of the foregoing claims 12 and 13, characterised in that the lubricating means (43) comprise a second channel (42) connected to the cylindrical hole (21), the second channel (42) leading onto the internal surface (22) of the cylindrical hole (21), at one of the grooves (41).
The engine according to claim 14, characterised in that the lubricating means (43) comprise a vacuum device (103) designed to draw excess lubricating fluid from the internal surface (22) of the cylindrical hole (21), the vacuum device (103) being in fluid connection with the second channel (42).
The engine according to claim 15, characterised in that the lubricating means (43) comprise a plurality of said channels (42) leading onto the surface (22) and arranged in succession along the groove (41).
The engine according to any of the foregoing claims from 1 to 16, characterised in that it comprises means (45) for cooling the cylindrical distributor (4).
The engine according to claim 17, characterised in that the cooling means (45) comprise a cooling duct (44) inside which a cooling fluid flows, the duct (44) extending at least partially inside the cylindrical distributor (4).
The engine according to claim 18, when claim 17 is dependent on one of the claims from 7 to 16, characterised in that the cooling duct (44) at least partially coincides with the lubricating duct (39), the lubricating fluid also constituting the cooling fluid.
The engine according to any of the foregoing claims from 1 to 19, characterised in that it comprises, for each cylindrical body (17), a first and a second port (25, 26) designed to be put into communication, by means of the cylindrical distributor (4), respectively with an exhaust duct (23) and an intake duct (24).
The engine according to any of the foregoing claims from 1 to 20, characterised in that the cylindrical body (17) is secured to the head (16) by means of forced screwing down.