DE8200418U1 - Internal combustion engine with improved components - Google Patents

Description

KENNECOTT CORPORATION
Stamford, Connecticut (V.St.AO

Internal combustion engine with improved components

The invention relates to an internal combustion engine with improved components, in particular an internal combustion engine for operation with diesel oil, carburetor fuel or alcohol with improved components in the valve system or force generation system. The valve system requires lubrication and its job is to fuel the combustion zone of the engine To remove inlet and exhaust gases from this zone, it essentially consists from inlet and exhaust valves, valve caps, valve guides, Valve spring retaining rings, valve rocker arms, bumpers and tappets. The power generation system aims to deliver power to the motor's drive shaft supply and consists essentially of exhaust systems for the combustion gases, cylinder liners, valve seats, exhaust linings, Exhaust pipes, flame plates, pistons, piston rings, piston pins and connecting rods.

Internal combustion engines are in an essential part of today Civilization and in everyday. Life almost omnipresent: in people and trucks, airplanes, diesel locomotives, even in lawnmowers and snow blowers. Given the current oil shortage and environmental efforts are improvements in performance or the environmental friendliness of internal combustion engines are very welcome and are used quickly. '.tet applied.

Recently, the automotive industry is due to consumer behavior and regulatory requirements strive to maintain the power-weight-ratio

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to improve ratio of internal combustion engines. Because a lighter engine can run at a higher speed and deliver more power, becomes a Emphasis placed on the development of lighter engine components. Reduced by reducing weight and inertia the use of lighter components also increases the stress on these components.

The development of components that have lower heat losses than metal is also a very worthwhile goal. The more heat in the engine remains, the more power can be generated with a given displacement, the fuel economy is thus improved.

^^ The object of the present invention is to provide improved moving parts

to provide for internal combustion engines. These components are stronger and lighter than steel, have a much better thermal

H resistance and lower thermal conductivity; you have a

fi · 15 here wear resistance, facilitate compliance with narrow Μαβί *
V tolerances and thus enable production with lower

^r Play that is maintained for a long time, even with major temperature fluctuations. The surfaces of the components have improved lubricating properties, so that oils or lubricants can be used that do not contain expensive additives or surfactants.

The advantages above are by using v - i overall @ l§ sintertem silicon as a material for the production of construction

parts achieved. As a raw material, a silicon carbide is used in ultra-fine Shape used. Components of the valve system, such as valve guides, valves, valve caps, rocker arms,

«·. Valve spring retaining rings, bumpers and tappets, and components of the power

_t ; generation system, such as cylinder liners, valve seats, exhaust

slot linings, exhaust pipes, flame plates, pistons, piston rings, Piston pins and connecting rods.

These components combine the advantages of high heat resistance, Hardness and wear resistance as well as a low weight with the further advantage that their surfaces are excellent Have adhesive properties for lubricants such as oil. Because of today

usual high compression, the greater heat generation and the longer intervals between oil changes in modern internal combustion engines Ren are numerous, sometimes exotic additives for engine lubricants has been developed. The components proposed according to the invention made of sintered silicon carbide have outer surfaces that are wetted by oil be. Excellent lubrication of surfaces subject to friction can also be achieved with low-viscosity lubricants without additives will. Therefore, engines containing these components can be lubricated with cheaper, lower quality lubricants.

In addition, the components according to the invention compared to the Metals commonly used in the manufacture of internal combustion engines are used, a very low coefficient of friction, Dry friction. This property is valuable when starting the engine when the contact surfaces are still dry or when through Damage during operation of the engine Oil losses occur. In these cases the wear and tear of the dry surfaces is not catastrophic. phal and does not lead to an immediate failure of the engine.

The silicon carbide used as starting material for the production of the components is an ultrafine material which can be obtained by grinding, grinding in a ball mill or grinding in a jet mill and then classifying or separating a silicon carbide consisting of coarser particles. Most preferably, the starting silicon carbide has a maximum particle size of about 5 µm and an average particle size of 0.10 to 2.50 µm. Since it is difficult to determine the particle size distribution of silicon carbide powders with particle sizes of less than 1 μm, the specific surface area can also be used to select a suitable material. The silicon carbide used to produce the components proposed according to the invention should have a specific surface area of 1 to 100 m ² / g. A powder with a specific surface area of 2 to 50 in ² / g is better and one with a specific surface area of 2 to 20 m ² / g is best.

The silicon carbide components proposed according to the invention can can be produced by various sintering processes. The components are best produced by pressureless sintering or reaction sintering.

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posed. Wherein substantially pressureless sintering the feinverteüte silicon carbide raw material is mixed with a small amount of excess carbon and a sintering aid and is sintered after forming in an inert atmosphere under substantially pressureless conditions at temperatures in the range 1900 to 2000 ⁰ C. Examples of processes for producing a silicon carbide sintered material suitable for the components according to the invention are described in US Pat. Nos. 4,124,667 and 4,179 ".99. During reaction sintering, the finely divided silicon carbide is mixed with carbon or graphite Adding a temporary binder to the desired shape and then heating to remove the binder and obtain a porous body. Silicon is infiltrated into the pores of the porous body. This treatment is usually in a vacuum induction furnace at temperatures in the range from 1400 to 1900 ^° C. and under a pressure of about 0.65 mbar Under these conditions, the silicon infiltrates the porous body and there forms silicon carbide with the carbon or graphite but still residues of free silicon, examples of such processes are in US-Pa publications 2,907,972, 2,938,807, 3,205,043 and 3,495,939. It has been proposed to use thermosets as temporary binders and to carbonize them later; in order to provide part of the carbon required for silicon carbide formation from the infiltrated silicon. Examples of such a procedure are described in U.S. Patents 3,947,550 and 4,044,110.

The components according to the invention are made of sintered silicon carbide produced by bringing the sintering mixture into the shape of the component to be produced and then sintering the blank. If if desired, the sintered component can be machined or polished in order to burn it to the desired dimensions. Another, but the more costly and less convenient method is from a block or rod of sintered silicon carbide go out and manufacture the desired component by grinding or machining.

The invention relates to the individual components of the valve system and the force generation systeresis of an internal combustion engine, but understand it turns out that the total friction of the engine parts is the lower u ->. d The more components according to the, the better the performance of the engine Invention are present in the engine.

A closer look at the valve system shows that the valve guides are usually pressed into the cylinder and the cylinder head. The valve stems are movably arranged in the valve guides. Inflow and exhaust valves are spring biased in one direction and open on an overhead engine Cams with the help of rocker arms and with an L-head engine Piston moves in the other direction. Each. Valve consists of one Valve head and a valve stem, which can be moved back and forth in one Valve guide is arranged. The stem end of the valve is either directly or indirectly via a valve cap with a rocker arm or fallow in connection. The valves allow the inflow the rCraftFtoff-air mixture into a cylinder and the outflow the products of combustion from the cylinder after ignition. The cheapest and most widespread arrangement is the arrangement with a deeper one Camshaft in which the valves are arranged above the piston and opened by pressing down in the cylinder τ / ürden. the Valve guides are arranged in the cylinder head. The valve is on the one hand by a hinged, horizontally extending rocker arm depressed, which in turn is actuated upon the upward movement of a vertical bumper which is substantially perpendicular is arranged to the valve stem and is moved by a camshaft by means of a tappet in a flat direction. The valve stem is usually lubricated by the fact that oil is supplied to the contact point of the rocker arm and valve stem and flows down the valve stem left to lubricate valve stem and valve guide. Because of the very little play, usually between the valve stem and the guide very little, if any, of that gets through. supplied Oil at the opposite end of the valve stem. Such valves therefore usually work dry with a squeaky, harsh noise.

With increasing wear of the guide or the valve stem runs

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excess oil through the guide to the valve disc, from where it is is sucked into the combustion chamber at an inlet valve, or

| ^r where an exhaust valve comes into contact with hot exhaust gases.

<§ In any case, the oil is burned, so that smoke in the exhaust gases

Ij, 5 occurs and the environment is additionally polluted. According to the invention

H proposed valve guides and valves allow preservation

t tight play over a long period of time - thanks to its wear resistance

the components and the ability of the sintered silicon carbide that

§ _y to ensure lubrication of the surfaces »ie the surfaces are wetted

10 and to keep covered with a film of oil. A rocker arm <* _e according to the

■; ΐ finding can be quite. ius sintered silicon carbide or au. ' a me-

■ ί | ^ tall, like steel, exist and at the contact points, z-.B. with the

^ P valve stem or valve cap on and with the tip of the

Bumper in a different place, have silicon carbide inserts.

Examination of the force training system reveals that the piston has a crown or head portion that holds or includes a number of rings for wiping off the oil and sealing the combustion chamber above the piston from the oil pan below the piston and preventing gas and oil passage . As a rule, there are two sealing rings, also known as compression rings, near the top of the piston head and one or more oil control rings under the sealing rings. available. The compression rings do not form a closed circle, ^^ but are finely divided and pretensioned so that they come out of the grooves,

in which they are housed expand, clinging tightly to the cylinder wall and create the desired seal in this way. The oil control ring or rings prevent further Oil has entered the cylinder. Therefore, when the piston is in a position near top dead center, there is little or no oil in the cylinder zone which adjoins the contact zone of the sealing ring, so that there is a wear of both the sealing ring and the Cylinder wall is coming. This will make the fuel consumption higher than without such wear, and over time the top of the cylinder expands, the top compression ring wears out, and the efficiency of the motor decreases.

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The top or head part of the piston acts as a reaction surface for the Burn in that. relevant cylinder of the engine. The upper part of the cylinder is enclosed by a flame plate. Below of the head part of the piston is a piston part which is open at the bottom and which supports the piston as it moves back and forth in the cylinder leads. On this piston part, which is open at the bottom, there are two approaches with continuous coaxial bores. Through every hole that is End of a piston pin out. A connecting rod encloses the central part of the piston pin at one end and one at the other end Connecting rod. When the internal combustion engine is operated with reciprocating pistons, a driving force is generated in the combustion chamber is generated by an expanding gas, from the piston head to the lugs, from these to the piston pin and then on to the Transfer connecting rod and crankshaft. According to the invention made of sintered silicon carbide pistons, piston rings and Cylinder liners allow very tight clearance to be maintained between the cylinder wall and the piston wall over a long period of time. The self-lubricating The effect of the silicon carbide surfaces has a particularly beneficial effect on the contact zones between piston rings and cylinders. thanks to The lightness of the silicon carbide components, their resistance to high temperatures, corrosion and erosion make them particularly suitable for use as flame plates, valve seats, exhaust port linings and exhaust pipes, being a more economical one Operation and a longer life of the engine. Piston pins and connecting rods as well as pistons and cylinder liners according to the invention can also be made from silicon carbide. The forces acting on the piston head are applied directly to the piston pin and then transferred to the connecting rod. These forces tend to deflect the piston pin and cause the part to flatten of the pin that is in contact with the piston lugs. The pin is then not exactly axially aligned with the piston lugs, which means that some of the driving force is applied to the outermost ends of the engine cylinder is concentrated. The repeated focus of forces can cause scoring in the cylinder wall and, in extreme cases, cause the piston to break through in the pin bores and in the Piston self-generated tensile stresses lead. The piston pins according to the invention have a very high Young's modulus and high hardness;

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they are therefore resistant to flattening and wear, have a low coefficient of friction, are lighter than steel and offer a better lubrication of surfaces subject to friction. The connecting rods are also best made from sintered silicon carbide and offer durability, rigidity, low weight and better lubrication conditions on the bearing surfaces.

The components according to the invention can advantageously be used individually will; however, it is particularly advantageous to use the invention in all components of internal combustion engines that are subject to friction and require lubrication, as the silicon carbide offers low friction due to good oil adhesion, high hardness and low weight.

The invention is explained in more detail with reference to the drawings. Show it:

1 shows a side view, partly in section, of part of an internal combustion engine with valve and piston components

according to the invention; as

Fig. 2 is a front part view of another embodiment a valve rocker arm, in which the valve rocker arm is made of metal, but at the contact points with the valve stem and the tip of the bumper parts,

made of silicon carbide. The drawing also shows a metal bumper with a silicon carbide tip.

In Figure 1 is a common internal combustion engine with an engine cover 11, cylinder head 13, engine block 15 and an oil pan 17 are shown. The complete valve consists of the actual valve 19, the valve guide 21, the valve spring retaining ring 23 and the valve rocker arm 25, the push rod 27 and the plunger 29. The valve spring retaining ring 23 is attached to the valve stem by a. Split ring 31 held, and on the stem of the valve 19 is a valve cap 33. In operation, the valve 19 moves in the valve guide 31 back and forth and is held in the closed position by the valve spring 35. When the camshaft 37 rotates, the cam 39 lifts the tappet

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29 and moves the bumper 1.7 against the force of the spring 41 above. The push rod 17 acts on part of the valve rocker arm 25 and causes the opposite T-part to move downwards. During its downward movement, this part engages the valve cap 33 and presses the valve 19 downwards against the force of the spring 35 in open position.

The components according to the invention are made of silicon carbide. The valve guide 21 is in the form of an elongated cylinder of relatively uniform diameter so that it fits into a bore of the cylinder block 13 can be pressed. The valve 19 can be moved in the valve guide 21 with a clearance of 0.025 to 0.13 mm. Thanks to the wear-resistant surfaces that can be wetted with lubricants are the valves and valve guides proposed according to the invention particularly suitable for overhead combustion engines in which valves and valve guides are lubricated by the fact that oil is allowed to flow down the valve stem. In addition, with the valves and valve guides currently in use, those in the engine Developed heat, especially in the area of the exhaust valves, heated the flange part of the valves and the heat on the valve stem

is transmitted. Under such conditions, the lubricant may be on The valve stem becomes charred, which reduces the clearance between the valve stem and valve guide and prevents further lubrication can. The thickness of the deposit increases until the valve sticks in the open position. This allows the piston to stroke no more work is transferred to the crankshaft, and the valve continues to burn. The valves and valve guides proposed according to the invention reduce the smudging problem as their surfaces are dated Lubricant are wetted and hold the lubricant. the Lubricated, wear-resistant surfaces of the valves and valve guides enable tight tolerances to be maintained over a long period of time and thus a reduction in engine noise by reducing valve noise.

The valve spring retaining ring 23 is at the end of the valve stem of the valve 19 and holds the valve ring 35. The valve spring retainer ring is in turn held by a metallic split ring 31,

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which is inserted into a circumferential slot on valve t'9. As shown, For example, a valve cap 33, preferably of the floating type, may be located at the end of the valve stem to rotate the valve and to reduce wear and tear. Valve caps, like the valve cap 33, are used more often with exhaust than with inlet valves. The rocker arm 25 is pivotably mounted on a bracket 43. The movement transmitted to the valve is directed vertically downwards, but since the rocker arm moves over an arc, a horizontal force component is created at the contact point.

This is caused at the top of the valve stem or the valve cap Scoring and wear at the point of contact with the rocker arm. The components proposed according to the invention made of sintered fine-grained Silicon carbide are particularly suitable for such applications because they are hard, stiff and wear-resistant and surfaces with low Have a coefficient of friction that hold the lubricant in place.

The opposite end of the rocker arm periodically comes into contact with the push rod 27, which descends down to z. U the plunger 29 which in turn rests against the cam 39. The cam 39 creates a reciprocating movement of the bumper 27. The use of rocker arms, bumpers and tappets made of silicon carbide according to the invention, thanks to their strength, their low weight, their high rigidity, wear resistance, low friction and high hardness make engine operation more economical.

The power generation system consists of a piston 45 with piston rings 47, a cylinder liner 49, a piston pin 51 and a connecting rod 53. The system also includes a flame plate 55, a valve seat 57, an exhaust port liner 59, and an exhaust pipe 61. A mixture of air and fuel is passed through an inflow valve is introduced into the combustion chamber 63 of a cylinder 65. After the fuel has burned, the piston 45 is moved downward and acts via the piston pin 51 on the connecting rod 53, which is also moved downwards, and exerts a force on the crankshaft 67 exercises. After combustion, during the exhaust stroke, the exhaust gases are passed through the exhaust slot 69 into the gas-tight attached to the cylinder head 13 Exhaust pipe 61 pushed out. The components according to the invention

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sintered fine-grain silicon carbide are suitable for use Particularly suitable in the power generation system of internal combustion engines because they are strong, hard, light and heat-resistant and beyond still have a very low coefficient of friction.

In Figure 2 is another embodiment of the rocker arm. Bumper and valve stem of existing assembly shown. at In this embodiment, the rocker arm 25 is made of metal, expediently Steel, machined and made in one or both points of contact with the valve stem or valve cap and the tip of the bumper provided with a wear insert or pad made of sintered fine-grain silicon carbide. As shown in Figure 2, are located the wear insert 71 of the rocker arm? 5 at the contact point with the valve stem part of the valve 19 and the wear insert 73 at the contact point of the rocker arm 25 with the tip 75 of the bumper 27. The bumper 27 can be made entirely of sintered silicon carbide manufactured or only at one or both ends with wear spots be made of sintered silicon carbide. As can be seen from Figure 2, the main part of the bumper 27 is made of metal made and attached to its end the tip 75 made of sintered silicon carbide. On the opposite one - not shown find the push rod 27, which comes into contact with the plunger 29, can also have a wear-resistant tip made of silicon carbide to be appropriate.

As can be seen, all components according to the invention are also used Engine components compatible and can be installed individually in common internal combustion engines, reducing the weight of the reciprocating parts is reduced and the engines with components be equipped with higher wear resistance and lower friction. But it can also be seen that the engines are so will be more efficient, the more components according to the invention be used.

The components according to the invention and their application are exemplified a four-stroke engine has been described, but it will be understood that the components can also be used in two-stroke engines.

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KENNECOIT CORP.

Stamford, Connecticut (V.St.A.)

SUMMARY

Internal combustion engine with improved components

This is an improvement in conventional internal combustion engines achieves that components of the valve device and the force generating assembly consist of sintered silicon carbide and silicon carbide fulver of ultrafine particle size have been produced »The components include valve guides, valves, valve caps. Valve rocker arms, valve spring shackles, push rods and tappets as well as cylinder liners, valve seats, outflow slot linings, Exhaust pipes, flame plates, pistons, piston rings, piston pins and connecting rods.

Fig. 1

Claims (21)

COHAÜ8Z & ^ LORACK PATENT AGENCY OFFICE SCHUMANNSTR. 97. D-4000 DÜSSELDORF Telephone: (0211) 683346 Telex: 08586513 cop d PATENT LAWYERS: DipWng. W. COHAUSZ DipL-lr.g. R. KNAUF · Dr .-! Ng., Dipl.-Wirtsch.-lng. «U GERBER · Dipl. Lng. K. B. COHAUSZ 01/08/1982 Ansp Gliche 1, internal combustion engine with a cylinder head and a cylinder block, a valve device, consisting of a number of valve ^. guides in the cylinder head, a number of valves with valve valve shafts which are movable in the valve guides, a number of valve spring retaining rings attached to the stem ends of the valves are arranged a number of rocker arms for moving the; Valves in the valve guides, a number of push rods, which engage with one end of the rocker arms and rest with the other ends za tappets that can be moved back and forth by cams, a force generating assembly consisting of a number of pistons with piston rings attached, which are in cylinder liners in the cylinder block are arranged, are movable, a number of piston pins, each piston } 15 connect with a connecting rod, a number of flame plates, Valve seats and exhaust port liners in the cylinder head |! | l as well as an exhaust pipe on the cylinder head, thereby characterized in that at least one component of the valve device or the force generating assembly is made of sintered Silicon carbide is made from silicon carbide of ultrafine particle size. 2. Internal combustion engine according to claim 1, characterized in that at least one component of the valve device consists of silicon carbide. 300
U / - 3. Internal combustion engine according to claim i, characterized that at least one component of the force generating assembly consists of sintered silicon carbide. 4. Brennkraffcmotor according to claim 1 or 2, characterized ge - 5 indicates that the valves (19) made of sintered f consist of silicon carbide. £ 5. Internal combustion engine according to claim 1 or 2, characterized in that g e - I indicates that the valve guides ^ 21) are made from - consist of sintered silicon carbide. I ^ "10 6. Internal combustion engine according to claim 1 or 2, characterized in that g e - i indicates that the Vantile spring retaining rings (23) from I consist of sintered silicon carbide. | 7. Internal combustion engine according to claim; h 1 or 2, thereby g e - ;. indicates that the valve device is a number 1 15 comprised of valve caps (33) made of sintered silicon carbide "' exist. !> ■ 8. Internal combustion engine according to claims 1 or 2, characterized in that it is '* indicates that the valve rocker arms (25) are made of i separate silicon carbide. I 20 9. Internal combustion engine according to claim 1 or 2, characterized in that i indicates that the valve rocker arm (25) is made of metal ι exist and with at least one wear insert. (71, 73) I sintered silicon carbide at the contact points with the bumper I gen (27) or the shafts or caps (23) of the valves (19) I am 25 see. J 10. Internal combustion engine according to claim 1 or 2, characterized in that (| indicates that the bumpers (27) are made of sintered "''' tem consist of silicon carbide. 11. Internal combustion engine according to claim 1 or 2, characterized that the bumpers (27) are made of metal and with at least one tip made of sintered silicon carbide at the point of contact with the cam (29, 39) or the tilting '5 levers (25) exist. 12. Internal combustion engine according to claim 1 or 2, characterized that the tappets (29) are made of sintered silicon carbide. 13. Internal combustion engine according to claim 1 or 3 _ä , characterized in that the pistons (45) consist of sintered silicon carbide. 14. Internal combustion engine according to claim 1 or 3, characterized that the piston rings (47) are made of sintered silicon carbide. 15. Internal combustion engine according to claim 1 or 3, characterized that the cylinder liners (49) are made of sintered silicon carbide. 16. Internal combustion engine according to claim 1 or 3, characterized that the piston pins (51) are made of sintered silicon carbide. 17. Internal combustion engine according to claim 1 or 3, characterized that the connecting rods (53) are made of sintered silicon carbide. 18. Internal combustion engine according to claim 1 or 3, characterized in that g e - indicates that the flame plates (55) made of sintered Consist of silicon carbide. 19. Internal combustion engine according to claim 1 or 3, characterized that the valve seats (57) consist of sintered silicon carbide. 20. Internal combustion engine according to claim 1 or 3, characterized that the Ausströtnschlitzlinungen consist of sintered silicon carbide. 21. Internal combustion engine according to claim 1 or 3, characterized that the exhaust pipe (61) consists of sintered silicon carbide.