WO2005021937A1

WO2005021937A1 - Internal combustion engine

Info

Publication number: WO2005021937A1
Application number: PCT/IB2004/002561
Authority: WO
Inventors: Giovanni Vano
Original assignee: Giovanni Vano
Priority date: 2003-09-01
Filing date: 2004-07-30
Publication date: 2005-03-10
Also published as: ITFR20030016A1

Abstract

An internal combustion engine has at least one piston (7) movable back and forth along a respective cylinder (5); an intake valve (20) for feeding an operating fluid into the cylinder (5); and an exhaust valve (21) for expelling combustion products from the cylinder (5); each intake and exhaust valve (20, 21) being defined by a tubular distributor (22), which has at least one opening (24) formed radially through the tubular distributor (22), and is movable about a respective longitudinal axis (16, 17) to selectively control opening and closing of a relative intake or exhaust conduit (18, 19).

Description

INTERNAL COMBUSTION ENGINE

TECHNICAL FIELD The present invention relates to an internal combustion engine. More specifically, the present invention relates to a four-stroke internal combustion engine, to which the following description refers purely by way of example. The present invention may obviously also be used to advantage in two- and six-stroke internal combustion engines. BACKGROUND ART In the manufacture of four-stroke internal combustion engines, an engine is known comprising at least one piston movable back and forth inside a respective cylinder; an intake conduit for feeding an operating fluid into the cylinder; an exhaust conduit for expelling combustion products from the cylinder; an intake valve for selectively controlling supply of the operating fluid along the intake conduit; and an exhaust valve for selectively controlling exhaust of the combustion products along the exhaust conduit. Each valve normally comprises a shutter member fitted in sliding manner to the cylinder head of the engine; a spring interposed between the shutter member and the cylinder head to move and normally keep the shutter member in a closed position closing the conduit; and a camshaft for moving the shutter member, in opposition to the spring, from the closed position to an open position opening the conduit. Known internal combustion engines of the type described above have various drawbacks, mainly due to the relatively complex, high-cost structure of the intake and exhaust valves, and the fact that the movements of the relative shutter members, springs, and camshafts involve relatively severe inertial forces and vibration. DISCLOSURE OF INVENTION It is an object of the present invention to provide an internal combustion engine designed to eliminate the aforementioned drawbacks, and which is cheap and easy to produce. According to the present invention, there is provided an internal combustion engine, as claimed in Claim 1. BRIEF DESCRIPTION OF THE DRAWINGS A non-limiting embodiment of the present invention will be described by way of example with reference to the accompanying drawings, in which: Figure 1 shows a schematic side view of a preferred embodiment of the internal combustion engine according to the present invention; Figure 2 shows a schematic side view, with parts in section and parts removed for clarity, of the Figure 1 engine; Figure 3 shows a schematic view in perspective of a detail in Figures 1 and 2; Figures 4 and 5 are similar to Figure 2, and show the engine in different operating positions. BEST MODE FOR CARRYING OUT THE INVENTION Number 1 in Figures 1 and 2 indicates as a whole a four-stroke internal combustion engine comprising a cylinder head 2; and a substantially cylindrical chamber 3 having a given longitudinal axis 4, and communicating with a number of cylinders 5 (in the example shown, four cylinders 5, only one of which is shown in the drawings) , each of which extends radially outwards from chamber 3 and has a longitudinal axis 6 substantially crosswise to axis 4 and parallel to axes 6 of the other cylinders 5. It should be pointed out that axes 6 of cylinders 5 may be aligned with one another, or arranged in a "V", or arranged in the form of opposed cylinders. A respective piston 7 engages each cylinder 5, slides along cylinder 5 in a straight, reciprocating movement comprising a forward stroke from a bottom dead centre position to a top dead centre position, and a return stroke from the top dead centre position to the bottom dead centre position, and is connected by a coupling device 8 to a drive shaft 9, which is normally common to all of pistons 7, is mounted for rotation inside chamber 3, coaxially with axis 4, and rotates about axis 4. Device 8 comprises a crank (not shown) fitted in angularly fixed manner to shaft 9 and rotated about axis 4 by a connecting rod 10, which is interposed between the crank (not shown) and piston 7, and extends between two axes 11, 12 parallel to axis 4, and of which axis 11 is the axis of rotation of connecting rod 10 with respect to the crank (not shown) , and axis 12 is the axis of rotation of connecting rod 10 with respect to piston 7. Cylinder head 2 comprises a plate 13, which is located on the opposite side of cylinders 5 to chamber 3, closes the top ends of cylinders 5, extends parallel to axis 4, and is substantially parallelepiped-shaped with a substantially rectangular section. Plate 13 has two longitudinal holes 14, 15, which have respective longitudinal axes 16, 17 parallel to each other and to axis 4, and communicate with each cylinder 5 via respective conduits 18, 19 formed through plate 13. In variations not shown, plate 13 may obviously be formed otherwise than as shown in Figures 1 to 5, and may, for example, comprise cooling fins. As shown in Figures 1, 2 and 3, holes 14, 15 are engaged in rotary and axially sliding manner by respective rotary distributors 20, 21, which are normally common to all of cylinders 5, and of which distributor 20 defines an intake valve for selectively controlling supply of an operating fluid

(combustion supporting air in the case of Diesel or injection engines, and fuel mixture in the case of spark-ignition Otto engines) along each conduit 18 into each cylinder 5, and distributor 21 defines an exhaust valve for selectively controlling exhaust of combustion products from each cylinder 5 along each conduit 19. Each distributor 20, 21 comprises a tubular member 22, which is mounted coaxially with relative axis 16, 17, has a first end closed axially by a wall 23 perpendicular to relative axis 16, 17, and has an axially open second end connectable to an intake or exhaust conduit (not shown) . Each member 22 has a number of (in the example shown, four) radial openings 24, which are equal in number to cylinders 5, are formed radially through member 22, are spaced along relative axis 16, 17 with the same spacing as conduits 18, 19, and are offset circumferentially with respect to one another. In connection with the above, it should be pointed out that, radially, the section of each opening 24 may be either constant or variable. With reference to Figure 1, distributors 20, 21 are rotated about respective axes 16, 17 by an actuating device 25 comprising, in the example shown, shaft 9, and a belt drive 26 in turn comprising a toothed belt 27 looped about three sprocket wheels 28, one fitted to shaft 9, and two fitted to members 22. Openings 24 are thus rotated by relative distributors 20, 21 about relative axes 16, 17, so as to face, and so open, relative conduits 18, 19, and so as to face plate 13 and so close relative conduits 18, 19. When openings 24 are positioned facing relative conduits 18, 19, distributors 20, 21 can be moved axially along relative holes 14, 15 to regulate the inlet section of relative conduits 18, 19 and selectively control operating fluid or combustion product flow along relative conduits 18, 19. Operation of engine 1 is easily deducible from the above description and Figures 4 and 5, is identical with that of a four-stroke internal combustion engine with conventional valves, and therefore requires no further explanation. It should be pointed out, however, that, in the example shown in Figures 4 and 5: distributor 20 is connected to and timed with shaft 9 so as to open each conduit 18 during a first forward stroke of relative piston 7, and therefore in advance with respect to the top dead centre position of relative piston 7 (Figure 4a), and to close each conduit 18 during a second forward stroke of relative piston 7, and therefore with a delay with respect to the bottom dead centre position of relative piston 7 (Figure 4c) ; and distributor 21 is connected to and timed with shaft 9 so as to open each conduit 19 during a first return stroke of relative piston 7, and therefore in advance with respect to the bottom dead centre position of relative piston 7 (Figure 5a) , and to close each conduit 19 during a second return stroke of relative piston 7, and therefore with a delay with respect to the top dead centre position of relative piston 7 (Figure 5c) . Engine 1 has several advantages, mainly due to distributors 20, 21 providing for a relatively straightforward, low-cost, compact engine 1. Distributors 20, 21 also provide for: relatively little dynamic stress of cylinder head 2; greatly reducing inertial forces and vibration, thus reducing the noise level of engine 1 and improving driving comfort; eliminating the inertial force balancing members required by internal combustion engines with conventional valves; relatively few moving parts, thus reducing friction and increasing the power of engine 1; relatively little load loss as the operating fluid or combustion products flow along relative conduits 18, 19, thus improving the volumetric efficiency of engine 1; and improving the overall efficiency of the vehicle.

Claims

1) An internal combustion engine comprising at least one cylinder (5) ; a piston (7) movable back and forth along said cylinder (5) ; an intake conduit (18) for feeding an operating fluid into the cylinder (5) ; an intake valve (20) for selectively controlling supply of the operating fluid along the intake conduit (18); an exhaust conduit (19) for expelling combustion products from the cylinder (5) ; and an exhaust valve (21) for selectively controlling exhaust of the combustion products along the exhaust conduit (19) ; and characterized in that each said intake and exhaust valve (20, 21) comprises a tubular distributor (22) having at least one opening (24) formed radially through the tubular distributor (22) ; actuating means (25) being provided to move each tubular distributor (22) and the relative opening (24) about a respective longitudinal first axis (16, 17), so as to selectively control opening and closing of the relative intake or exhaust conduit (18, 19) . 2) An engine as claimed in Claim 1, and- also comprising a drive shaft (9) mounted for rotation and rotated about a respective longitudinal second axis (4) by the piston (7); the tubular distributors (22) being interconnected and timed with each other and said drive shaft (9) . 3) An engine as claimed in Claim 2, wherein said first axes (16, 17) are substantially parallel to each other and said second axis (4) . 4) An engine as claimed in Claim 2 or 3, wherein said actuating means (25) comprise said drive shaft (9); and a drive device (26) connecting the tubular distributors (22) to each other and to the drive shaft (9) . 5) An engine as claimed in any one of the foregoing Claims, wherein each tubular distributor (22) has an axially closed first end (23); and an axially open second end connectable to a further intake or exhaust conduit. 6) An engine as claimed in any one of the foregoing Claims, and comprising a number of said cylinders (5) having respective longitudinal third axes (6) substantially parallel to one another and crosswise to said first axes (16, 17) . 8) An engine as claimed in Claim 6 or 7, wherein each tubular distributor (22) comprises a respective said opening (24) for each said cylinder (5) . 9) An engine as claimed in Claim 8, wherein the openings (24) of each tubular distributor (22) are spaced along the relative first axis (16, 17) with a spacing substantially equal to the spacing of the cylinders (5) , and are offset circumferentially with respect to one another.