JPS6246683B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a device for scavenging a cylinder of a two-stroke internal combustion engine and supplying air or a mixture to it, and in particular, it relates to a device for scavenging a cylinder of a two-stroke internal combustion engine and supplying it with air or a mixture. Air ducts are provided in the cylinder head, these air ducts being closable by means of at least one axial slide disposed on the surface of the cylinder head adjacent to the combustion chamber and having controlled intermittent oscillations; Air conduits and corresponding openings in the axial slide are arranged in at least two rows around the centrally mounted cylinder head element for supplying or igniting the fuel. This invention relates to a scavenging air supply system for a two-stroke internal combustion engine.

[Conventional technology]

If the cylinders of a two-stroke internal combustion engine are optimally scavenged and filled with air or air-fuel mixture, a maximum amount of scavenging air, equivalent to a piston that almost completely blocks the entire cross section of the cylinder, will enter the cylinder and prevent its internal combustion. It goes without saying that the scavenging air by pushing out the gas and using the air-fuel mixture of the two-stroke internal combustion engine can be achieved almost in accordance with the theory. Theoretical to perform scavenging air, the sum of the opening cross-sectional areas of all inlet valves is equal to the maximum effective flow area, i.e., the product of the geometric passage area and the flow coefficient is maximized to direct air to the complete piston body. You have to move it like this. A device of the above-mentioned type, which produces a piston-like air movement with almost no turbulence, has been proposed in DE 2907533.

[Problem that the invention seeks to solve]

However, it is extremely difficult to implement the proposal in the above-mentioned West German Publication. This is because the axial slider in direct contact with the combustion chamber is subjected to high temperature and pressure conditions, and thermal expansion and high pressure effects cause distortion and irreversible bulging, which at least impairs the operating reliability and sealing effect of the slider, and the slider This is because it wears out.

[Means for solving problems]

The aim of the invention is to reduce axial stresses and minimize wear without reducing operational reliability.

Therefore, there is provided a cylinder scavenging filling device for a two-stroke internal combustion engine according to the invention, which scavenging filling device comprises:
A swinging slider is provided between the cylinder head and the combustion chamber in the cylinder, and this slider makes it possible to close the air passage that extends inside the cylinder head almost parallel to the cylinder axis, and this slider allows the combustion chamber side to be closed by the air passage. The valve plate is protected by a valve plate which is cooled by a valve plate and which is provided with an orifice aligned with said air passage, and which is connected to the cylinder wall at its outer periphery and to the center of the cylinder head at its center. The valve plate is supported by a flange of a tubular member extending around a fuel injection igniter, the valve plate having coolant passed therethrough, and the valve plate and the slider having:
It is configured to move in the cylinder axial direction in response to pressure reversal between the combustion chamber side and the air passage side.

[Effects and operations of the invention]

The valve plate, through which the coolant passes, protects the axial slider from overheating and fouling. If the combustion chamber or cylinder chamber is under excessive pressure, that is, during the compression stroke or at the beginning of the expansion stroke, the closed slider is pressed against the base of the cylinder head by movement in the axial direction of the valve plate, and the valve plate itself is also pressed against the slider. Press to seal.

On pressure reversal, ie, when the air pressure in the air passage or inlet becomes higher than the pressure in the combustion chamber, the valve plate lowers and is disengaged from the axial slider. The valve plate is also separate from the bottom of the cylinder head. The axial movement of the slider is limited to exactly half the "axial travel" of the valve plate, preventing the valve plate from creating a gap in which it can freely rotate to either side. In order to open and close the air passage, the valve plate undergoes an intermittent oscillatory movement, but in this state the slider floats between the cylinder head and the valve plate, so that it is not worn out.

If an orifice communicating with the orifice of the axial slider in the closed position is formed adjacent to the air passage or inlet, the opening movement, especially the closing movement, of the axial slider and the valve plate can be significantly facilitated. . During closure, this aperture serves, for example, as a vent for air trapped in the continuous orifice provided in the slider and in the gap between the slider and the valve plate or cylinder head.

The valve plate is adjusted relative to the cylinder head to ensure that the air passageway in the cylinder head is always properly positioned relative to the aligned valve plate orifice during axial movement of the valve plate. The students were guided through the exercise in a way that made them feel comfortable. This adjustment and guidance of the valve plate can take place, for example, at the transition part of the coolant line from the cylinder head to the valve plate; this transition part also ensures a tight seal over the axial movement of the valve plate. It can also have a sealing element.

It is advantageous if the valve plate consists of two rigidly interconnected discs made of materials with mutually different coefficients of thermal expansion. By appropriate selection of the two materials mentioned above, the positive curvature of this valve plate in the direction of the combustion chamber, i.e. the convex curvature, can be limited, and in some cases even zero. , there is no negative curvature at any possible temperature, so that the cyclic bending stresses that may occur during operation can be maintained at a low level. In addition, various measures have been taken to prevent fine dust and combustion products from adhering to the surface supporting the valve plate near the cylinder chamber, which over time becomes baked and reduces the valve stroke. can be taken. Advantageously, the valve plate bears with its outer edge into the cylinder wall, with a horizontal gap being defined between it and its supporting surface, and/or the valve plate has a skirt extending into the combustion chamber and this Since the skirt defines a gap spaced apart from the cylinder wall to cooperate with the horizontal gap, fine dust particles cannot enter because the gap volume is compressed. For the same reason, the valve plate can be made to rest with its inner circumference on the ring flange of the tubular member with a protrusion or edge that minimizes the support surface, thus reducing dust buildup in the stroke. can be pushed out effectively.

The slider is connected to a sleeve that extends coaxially around the tubular member and passes through the cylinder head, terminating at the top in a flange from which at least one arm extends radially to the transmission. extending outwardly through an aperture in the intermediate ring, the aperture extending over the pivoting range of the arms, and providing for the intermediate ring to mount the fuel injection and ignition device on the cylinder head; A slider transmission device with a simple structure can be provided. In this case, a deformable ring diaphragm is introduced as a sealing element between the valve plate and the axial slider or its sleeve on the one hand, and the tubular member on the other hand, so that no overpressure in the combustion chamber occurs. , the diaphragm can be pressed against the sealing edge of the axial slider by means of a valve plate.

〔Example〕

The invention will now be described in detail with reference to the embodiments illustrated in the accompanying drawings.

Briefly, the combustion chamber or cylinder chamber 1 of the cylinder 2 of the diesel engine shown is closed off at its top by a cylinder head 3 which has a fuel injection device 4 in the center. A piston 6 is inserted into the cylinder 1.

The cylinder head 3 has an air duct 7 for supplying air in the case of a diesel engine and for supplying a mixture in the case of an automatic engine. The passage 7 is arranged in three rows 9, 9a, 10 concentrically with the cylinder axis.
The holes are arranged in the longitudinal direction of the cylinder head 3. These holes are in each row 9, 9a, 10
They have different diameters. cylinder 1
communicates with the air chamber 8, which is shown in a simplified manner, via rows 9, 9a, and 10. The controlled opening and closing of the air channels or boreholes 7 is effected by an axial slide 11 which is provided with a through orifice 12 corresponding in arrangement, shape and size to the borehole 7 .

According to the invention, a valve plate 31 is interposed between the combustion chamber 1 and the axial slider 11, and the valve plate 31 has an orifice 32 corresponding to and aligned with the passage 7.
is formed. In the illustrated example, the valve plate 3
1 consists of two discs 31a, 31b which are rigidly interconnected to each other and a flow channel 33 for a coolant, for example water, arranged between the two discs. As already mentioned, the discs 31a, 31b are advantageously made from mutually different materials; for example, the disc 31a on the side of the combustion chamber 1 is made from carbon steel, and thus the disc 31b, for example made from rust-free steel. It can be made to have a coefficient of thermal expansion lower than .

Making the valve plate 31 in the form of two disks 31a, 31b simplifies the provision of the coolant channel 33 in one of the disks, and by selecting the appropriate material for the disks, It is possible to sufficiently reduce the protrusion of the valve plate 31 toward the combustion chamber 1 due to thermal expansion.

The valve plate 31 is attached to the cylinder head 3 on the cylinder side wall.
via its outer edge in a recess 43; the axial depth of the recess 43 is determined by the effect of the reversal during one cycle of the pressure gradient between the air chamber 8 and the combustion chamber , is determined in relation to the thickness of the valve plate 31 to such an extent that the valve plate 31 can move in the axial direction and secure sufficient clearance for the slider 11. A valve plate 31 is arranged around the injection nozzle 4 and abuts at its inner circumferential surface on a tubular member 34 which has a ring flange 35 at its bottom end. The injection nozzle 4 also connects to the ring flange 3 via a seal 15.
5 or carried by member 34.

The valve plate disk 31a is extended to some extent to form a skirt portion 37, and a gap 36 is defined between the skirt portion and the cylinder wall. The gap 36 terminates at its top in a second horizontal gap 38. This second horizontal gap 38 is defined by the outer edge of the valve plate which provides a bearing and sealing surface. Both gaps 36, 38 serve to prevent the accumulation and trapping of combustion products and dust in the gas mass in the combustion chamber 1, the volume of the gas mass entering the gaps 36, 38 being determined by the geometry of the combustion chamber 1. It is approximately 1/6 of the target volume. Dust enters the gaps 36, 38 during compression, but is blown out by the subsequent scavenging air of the combustion chamber 1. The enlarged gaps 36 and 38 are formed to receive the aforementioned amount of air flowing from the combustion chamber 1 into the clearance space around the slider 11 and the valve plate 31. Although this air may be contaminated by soot particles, the air flowing into the narrow gap consists solely of pure air from the enlarged section that has been cleaned by the previous scavenging air flow. Experience has shown that if you blow the gaps regularly, soot will not clog the gaps a few millimeters wide. To prevent the accumulation of impurities, the device for impinging the valve plate 31 on the ring flange 35 is designed with jagged teeth 39 (FIG. 4) to avoid leaving a surface on which fine dust particles can accumulate. It is being done.

The coolant between the discs 31a and 31b is supplied through a hole 40 which extends into the cylinder head 3 and terminates in a tubular member 41 which reaches into the disc 31b. The clearance required for axial movement of the valve plate 31 is given by the difference between the axial depth of the recess 43 in the cylinder head 3 and the thickness of the valve plate 31.
The coolant that has entered the valve plate 31 is sealed by an O-ring provided on the outer circumference of the valve plate 31. A member 4 extending into the disk 31b with a slight gap
1 also prevents accidental rotation and also guides the axial movement of the valve plate 31. The valve plate 31 also has an orifice 32 aligned with the air passageway 7.

In the closed position of the slider 11, the slider 1
The pressure in the cylinder acting on the total area of 1 and the valve plate 31 produces a closing force equal to the product of said pressure multiplied by the cylinder pressure, but the scavenging pressure from above acts on the sum of all the pressures in the cylinder head. do. Therefore, a scavenging pressure considerably in excess of the pressure in the cylinder is required to move the valve plate and slider downward. In order to reduce this pressure difference, an additional orifice 5 is formed in the cylinder head 3, which connects the orifice 12 of the axial slide 11 with the air chamber 8 in the closed position. The orifice 5 does not necessarily need to be provided so as to pass through the cylinder head 3 in the longitudinal direction. That is, the orifice 5 may be formed in any way as long as it can connect the orifice 12 and the gas space of the air chamber 8 when the slider 11 is in the closed state.

The axial slider is also arranged to move axially about half the stroke of the valve plate 31 and is arranged in a recess 4 provided in the base of the cylinder head 3.
It is arranged for rotational rocking within a second recess 44 of diameter smaller than 3.

The slider 11 is held by a sleeve 14 coaxially surrounding the member 34 and extending through the top of the cylinder head 3. The outer surface of the sleeve 14 is rotatably mounted on two radial bearings 17 separated by a spacer 16.

The top end of sleeve 14 is adjacent closure ring 18 . This closing ring 18 is adapted to be removably engaged on the sleeve 14 via teeth 21 and held on the sleeve 14 by bolts 22, so that assembly is easy. As can be seen in FIG. 2, the ring 18 is connected by three radially outwardly extending arms 19 to a toothed ring 20 which meshes with a gear 24 on a drive shaft 23.

An axial bearing 25 receiving means having elements 18, 14, 11 is arranged at the top end of the cylinder head 3; this axial bearing bears with its inner edge on a shoulder formed in the cylinder head. The axial dimension of the bearing is determined so that the slider 11 can move by half of the stroke of the valve plate 31 when descending.

The member 34 has a ring flange 35 for supporting the injection nozzle 4 and for supporting the inner edge of the valve plate 31, and a tubular spacer 45 is fixed to the outside of the member 34. The upper end of the spacer 45 is connected to the member 34
It impinges on the shoulder and against the main flange 46 which is secured by nuts 47.

The bottom end of the spacer 45 acts as an airtight bearing surface for one end of the elastically deformable ring diaphragm 48. The elastically deformable ring diaphragm 48 is
Spacer 45 and sleeve 14 or slider 11
This seals the gap between the The gap is in fluid communication with the combustion chamber 1 when sealed. The other end of the diaphragm 48 is the inner end of the disk 31b when the valve plate 31 is in the bottom position - i.e. in the position that the valve plate 31 occupies when there is a pressure drop between the air chamber 8 and the combustion chamber 1. Tubular groove 49 provided in the rim (Fig. 3a and 3)
(shown in Figure b). In the top position, the valve plate 31 presses the slider 11 against the base of the cylinder head 3, but after the valve plate 31 has moved axially to the top position, the diaphragm 48 is deformed as shown in FIG. 3b. and the slider 1 which presses against the valve plate 31 and the shoulder-shaped sealing edge 50 of the inner edge of the slider 11.
1. Due to this fastening, even if the pressure inside the cylinder increases during compression and the pressure difference acting on the diaphragm 48 becomes large enough to overcome the elastic closing force of the diaphragm itself, the outer edge of the diaphragm is lifted and the pressure is increased. It is possible to obtain reliable high sealing performance without escaping.

The member 34 rests on the cylinder head 3 by means of a circular flange 46 and an intermediate ring, and the bolt 28
(FIG. 2), the ring 29 and flange 46 are fixed on the cylinder head 3. The extension angle of the opening of the passage 30 formed in the ring 29 is such that it can at least cover the pivot range of one arm 19 extending radially outward. The passage 30 makes it possible to support the injection nozzle 4 in the center of the cylinder head 3 without interfering with the oscillating opening and closing movements of the slider 11.

[Brief explanation of the drawing]

Figure 1 is a longitudinal sectional view through the left half of the cylinder head of an internal combustion engine taken along line - in Figure 2, Figure 2 is a sectional view taken along line - in Figure 1, Figures 3a and 3b. 4 is a sectional view taken along the line ``--'' in FIG. 3a. DESCRIPTION OF SYMBOLS 1...Cylinder chamber, 2...Cylinder, 3...Cylinder head, 4...Fuel injection device, 6...Piston, 7...
Air passage, 8... Air chamber, 9, 9a, 10... Row of passages, 11... Slider, 12... Penetration orifice, 3
DESCRIPTION OF SYMBOLS 1... Valve plate, 32... Orifice, 33... Coolant duct, 34... Tubular member, 35... Ring flange, 3
6, 38... Gap, 37... Skirt portion, 41... Tubular member.

Claims (1)

[Claims] 1. In a cylinder scavenging air filling device for a two-stroke internal combustion engine, the cylinder head is provided with an air passage extending substantially parallel to the cylinder axis, and the cylinder head and the combustion chamber of the cylinder are connected. An oscillating slider is provided between the two cylinders, and the air passage can be closed by the slider, and the arrangement pattern of the air passage surrounds a fuel injection and ignition device mounted in the center of the cylinder head. The slider is protected on its combustion chamber side by a fluid-cooled valve plate, the valve plate is provided with an orifice aligned with the air passage, and the valve plate is attached to the cylinder wall at its outer periphery. supported by a flange of a tubular member extending at its center around the fuel injection and ignition device, the valve plate and the slider comprising:
A cylinder scavenging air filling device configured to be able to move in the cylinder axial direction in response to a pressure reversal between the combustion chamber side and the air passage side. 2. The apparatus according to claim 1, wherein the cylinder head is provided with another orifice adjacent to the air passage, the other orifice being arranged to open the slider when the slider is in the closed position. A device configured to align with the orifice. 3. A device according to claim 1 or 2, wherein the valve plate is movable relative to the cylinder head and is configured to be guided in its axial movement. 4. In the device according to any one of claims 1 to 3, the valve plate comprises:
A device consisting of two disks made of rigid materials with different coefficients of thermal expansion joined together. 5. A device according to any one of claims 1 to 4, wherein the valve plate is adapted to be supplied with coolant via the cylinder head. 6. The device according to any one of claims 1 to 5, wherein the valve plate defines a horizontal gap between its outer periphery and the cylinder wall supporting it; The horizontal gap is configured to open into the combustion chamber. 7. The apparatus of claim 6, wherein the valve plate has a skirt extending into the combustion chamber at an annular clearance from the cylinder wall. 8. In the device according to any one of claims 1 to 7, the valve plate is supported on the flange of the annular member via jagged teeth, and the supporting area thereof is A device configured to be minimized.