US2170020A

US2170020A - Internal combustion engine

Info

Publication number: US2170020A
Application number: US165869A
Authority: US
Inventors: Gerlach Manfred
Original assignee: Messerschmitt Bolkow Blohm AG
Current assignee: Airbus Defence and Space GmbH
Priority date: 1936-09-30
Filing date: 1937-09-27
Publication date: 1939-08-22
Anticipated expiration: 1956-08-22

Description

Aug) 22, 1939.

M. GERLACH INTERNAL COMBUSTION ENGINE Filed Sept. 27, 1937 2 Sheets-$heet 1 Aug. 22, 19 39. M. GERLACH INTERNAL COMBUSTION ENGINE 2 Sheets-Shed 2 Filed Sept. 27, 1937 obtain a higher 'efliciency.

Patented Aug. 22, 1939 2,170,020 INTERNAL COMBUSTION ENGINE Manfred 'Gerlacll, Aken-on-the-Elbe, Germany, I minor to Junkers Flugzeugand-Motorcawerke Aktlengesellschalt, Deccan, Germany A'ppllcatlonseptember 21,1937, Serial No.'185,869. m can September 30,1936

claims (craze-551 This invention relates to internal combustion.

engines and more especially to that kind of engine in which the admission of air or fuclorj both iscontrolled by the piston governing the intake ports.

It is anobjectof my invention to improve the operation of such engines by improving the form and arrangement of these intake ports sons to Other objects of this invention will appear as the specification proceeds.

In internal combustion engines the area of passage for the medium entering the cylinder has already been subdivided into a great number of '17- small ports which are arranged in a plurality of axially spaced' circular sections and the axes of which are disposed at an angle to the cylinder radii. Hitherto intake ports of this kind were so arranged that the axes of all ports werearranged at the same angle relative to the cylindrical inner-wall of the cylinder.

Practical experience has shown that even in cylinders formed with intake ports of the k nd described the scavenging operation does not pro'-' ceed in an altogether satisfactory manner. This is substantially due to the circumstance that in the scavenging step two requirements must be fulfilled which appear to counteract each other,

Whenoisplacing the waste gases by the fresh gases these two'kinds of gases should mix with each other as little as possible in order that the spent gases be removed from the cylinder as completely as possible. I

On the other hand in order that the air of combustion admittedinto the cylinder be able to intimately permeate the fuel as required for a satisfactory combustion, it is important, quite especially in the case of engines operated with fuel injection, to impart to the fresh gases a vigorous eddying movement'whlch shall even continue after the scavenging operation has come to an end. I

If intake ports are provided, the walls of'whlch are directed substantially tangentially to the inner cylinder wall, a vigorous eddying movement is obtained, but owing to the centrifugal forcescreated by this movement the cooler and consequently heavier fresh gases are forced towards the outside, while the warmer and consequently lighter waste gases are left in the central portion of the cylinder, so that here a core of hot waste-"gases is retained.

If, in order a avoid as far as possible the for-' mation of such core, the intake ports are arranged with their axes directedmore radially, the eddying movement is reduced and the feed of fresh air to the fuel admitteddnto the cylinder wjll'be unsatisfactory, so that only a smaller quantity of fuel can be brought to complete combustion and the engine output will be lower. 5

This invention is intended to obviate these drawbacks by providing scavenging means which allow fulfilling the two requirements defined above, viz. a complete scavenging of the cylinder and the creation of a vigorous eddying movement in the fresh charge, although these two requirenients "appear to contradict each. other to a certain extent.

In accordance with this invention the perforations of the cylinder wall, which form the intake ports and which are arranged in more than two axially spaced circular rows, are so disposed and formed, that the axes of the ports forming the individual rows ,extend at different angles relative to a radius intersecting the inner opening of the port, the angle enclosed between the port inthe cylinder.

The axes. of the ports in the diilerent rows may further be inclined differently relative to the cylinder axis, their inclination towards the combustlon space being the greater, the closer the ports are disposed relative to the combustion space. The axes of the ports. spaced farther away from 39 the combustion space may extend normally to the cylinder'ax is or may even be directed somewhat towards the outer end of the cylinder.

In the drawings afiixed to this specification and forming part thereof Figs. 1 to 5 illustrate diagrammatically by way of. example a working cylinder, embodying my invention, of an internal combustion engine o'f the opposed piston type,

Fig. 1 being'an axial section of the cylinder and the pistons reciprocating therein, while Figs. 2 to 5 are cross sections on the lines 11-11, IIIIII, IV-IV and VV respectively in ,Fig. 1, of the rows of intake ports. 1

Figs. 6 to 8' are axial cylinder sections serving to illustrate diagrammatically the operation of the invention.

formed by a plurality of circular rows of perforations 3, 8, Band 6, respectively, arranged in series in the axial direction of the cylinder wall.

The perforations 3 which adjoin the combustion space forming the middle part of the cylinder are so arranged that their axes, if viewed in the longitudinal section shown in Fig. l, are strongly inclined relative to the cylinder axis in the direction towards the combustion space, while, if viewed in cross section (Fig. 2), they considerably deviate from the radial direction, being directed more tangentially. In the other rows of

ports

4, 5 and 6 the port axes are gradually less inclined relative to the combustion space, so that the axes of the ports constituting the row 5 extend normally to the cylinder axis, while the axes of the outermost row 6 are even slightly inclined towards the other side, i. e. towards the outer end of the cylinder. If viewed in cross section, as illustrated by Figs. 3 to 5, the deviation of the direction of the port axes from the radial direction is the smaller, the farther outwardly the row of ports is arranged, and in row 6 the port axes are even radially directed.

During an outward stroke of the piston Ill controlling the intake ports (Fig. 6) the ports 3 of the row adjoining the combustion space are the first to be uncovered. The fresh gases accumulated in the reservoir 1 (Fig. 1) under a certain increased pressure now enter the cylinder through the ports 3 and displace a part, corresponding to their volume, of the waste gases in the cylinder by expelling them through the exhaust ports which were already, at least partly, uncovered. The path through which these fresh gases travel, extends, in accordance withthe direction of the axes of the ports 3, in the form of a high pitch helix in the outer part of the cylinder space. As indicated in Fig. 6, the fresh gases thus fill an outer annular zone a with a vigorous longitudinal and circular flow, while the core b is formed substantially by stationary waste gases.

The piston ill in continuing its outward stroke uncovers the ports I. Since the axes of these ports arearranged at a larger angle to the cylinder axis and deviate to a lesser extent from the radial direction than the ports 3, the fresh gases entering through ports 4 (as indicated in Fig. '7) will move substantially in an annular zone 0 enclosed in the annular zone 0. Within the annular zone c there again remains a core b of waste gas, which is however considerably smaller than the core b in Fig. 6.

Thus during the outward stroke of the piston l0 and the gradual uncovering of the consecutive rows of intake ports the core of waste gases is gradually diminished, until, when uncovering the outermost row of ports 6 (Fig. 8), the radially entering scavenging gases meet inthe center of the piston bottom and are thus deflected in the direction of the cylinder axis, whereby also the innermost core of waste gases is altogether expelled from the cylinder space.

Thus the new arrangement of the intake ports results in a very complete expulsion of the waste gases from the interior of the working cylinder.

During the return stroke of the piston It! the row of ports 3, the axes of which deviate mostly from their radial direction, is the last to be covered. In consequence of this the scavenging gas current is imparted up to the end a powerful rotatory impulse, so that the fresh gases present in the cylinder, after the intake ports have been closed, will owing to their inertia rotate further. This rotatory movement of the fresh gases greatly favors the intimate mixture of the air of combustion with the fuel, which may for instance be injected into the cylinder through a nozzle l2. This shows that both requirements defined above are fulfilled by the invention.

Various changes may be made in the details disclosed in the foregoing specification without departing from the invention or sacrificing the advantages thereof.

I claim:

i. In an internal combustion engine having a cylinder, a piston operable in said cylinder and exhaust ports; an exhaust gas scavenging system comprising means for progressively passing at difierent angles with respect to the longitudinal axis of said cylinder scavenging gas into adjacent portions of the interior of said cylinder and with a swirling motion toward said exhaust ports whereby exhaust gases are scavenged without admixture with the'turbulent intake gases.

2. In an internal combustion engine having a cylinder including a combustion chamber, a piston movable in said cylinder along the longitudinal axis thereof, and exhaust ports; a plurality of rows of intake ports-arranged peripherally of said cylinder, the axes of the ports of each row being of different inclination with respect to said longitudinal axis, and the radii of the cylinder, than the axes of the ports of the adjacent rows, said inclination of said port axes with respect to said radii of said cylinder being the greater the nearer the respective row of ports lies to said exhaust ports and with respect to said axis being less the nearer the row of ports lies to said exhaust ports.

. cylinder and at a different angle to a plane perpendicular to said axis, and means to supply scavenging gas to said spaced means.

4. In an internal combustion engine having a cylinder, a piston movable in said cylinder, and exhaust ports located at one end of said cylinder; a plurality of rows of inlet ports arranged at the other end of said cylinder, said rows of inlet ports being spaced from each other in a direction longitudinally of said cylinder, a first row of said inlet ports having the axes of said ports inclined with respect to the longitudinal axis of said cylinder to direct inlet gas toward said exhaust ports and further inclined with respect to the radii of the plane of the circle in which said first row lies to direct inlet gas in a first path adjacent and parallel the inner wall of said cylinder, a second row of said inlet ports having the axis of said ports each inclined with respect to said longitudinal axis at an angle greater than the inclination of theaxes of said first row of ports, said axes of said second row of ports being further inclined to direct said inlet gases in a second path adjacent and parallel to said first path, and at least a third row of said inlet ports having the axis of each port inclined-with respect to said longitudinal axis at an angle greaterthan the inclination of the axis of said second row of ports, and further inclined to direct inlet with-respect to the axes or the ports in adjacent gas in at least athirdpath lying inwardly of and parallel to said second path.

5-. In an internal combustion engine having a cylinder, a piston movable in said cylinder, and exhaust ports; and exhaust gas scavenging system comprising at least three rows of intake ports spaced from each other and from said exhaust ports longitudinally of said cylinder and adapted to be successively covered and uncovered by said piston, the axes of the respective ports in one row of said intake ports being diflerently inclined rows both with respect to a plane containing the longitudinal axis of the cylinder and the radii of said cylinder whereby intake gases enter said cylinder from each row of intake ports as they are uncovered successively by said piston to scavenge separate portions of said cylinder, and exhaust gases are scavenged without mixing with intake gases while the intake gases are in turbulent state for mixing with injected fuel.

7 MANFRED GERLACH.