DE2722176A1 - Compression ignition engine with working piston - has auxiliary piston in bore in working piston crown to absorb peak pressures - Google Patents

Abstract

The compression ignition engine piston crown has a bore which is closed by a flexible metal diaphragm. The bore is subject to gas pressure equal to or slightly less than the working pressure. The diaphragm will move towards the bore should the working pressure exceed the normal and thereby increase the combustion chamber volume. an alternative design employs the same principal by using a sprung plunger in place of the diaphragm. The plunger absorbs excess energy and returns it at the end of the combustion stroke. The pistons of a rotating double cylinder engine could have similar auxiliary pistons actuated by centrifugal force. Each auxiliary piston contains a fuel injection plunger fed by a fuel bore passing through the working piston as far as the centre shaft to joing a main fuel feed.

Description

Mannheim, May 4th, 1977

Jochen Jesinghaus
Scharnhorst street 12

6800 Mannheim-Feudenheim 51

Internal combustion engine with compression ignition

The invention relates to an internal combustion engine with compression ignition, with a cylinder, with a combustion chamber, a working piston and an injection device.

In internal combustion engines with compression ignition, the air in the cylinder in self-priming engines is set to 3o
up to 4o at, with supercharged engines up to 60 at and more
compressed and thereby heated to 600 to 700 ° C. Of the
Fuel injected towards the end of the compression stroke evaporates and ignites. Thereby the combustion goes

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mostly from the edge of the fuel jet and gradually captures according to the continuously supplied fuel. The combustion can now be controlled by timing the injection quantity Fuel are guided so that the pressure in the combustion chamber remains approximately the same during the entire injection process, in this The case is referred to as constant pressure combustion. However, so-called ignition pressures arise when igniting, which is the case with larger ones Diesel engines between 45 and 55 at, for smaller ones between 60 to 7o at and even over 10o at when charged can. Therefore, the bearings and the entire load capacity of the engine must be designed according to the peak of the ignition pressures will.

Attempts have been made to reduce this ignition pressure by means of various designs of the combustion chamber. In the NAN-M diesel engine, for example, there is an approximately spherical combustion chamber in the piston. The fuel is sprayed onto the wall of this piston burner in the form of a thin film. The mixture created by the vaporized fuel and the air flow blowing over the filin burns relatively slowly. The rate of pressure increase remains somewhat slower than with normal diesel engines (approx. 1.8 to tat / ° crank angle). However, in this diesel engine too, the ignition pressure is still higher than the compression pressure. A constant pressure, however, protects the bearings of the motor and, above all, causes it to run smoothly.

The invention is therefore based on the object of an internal combustion engine to create with self-ignition of the type mentioned, in which the pressure within the Brennr chamber is practically always the same during the entire combustion process, with none above the working pressure higher ignition pressure should occur.

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The solution to the problem is that according to the invention within the cylinder or the Arbeltskolbens one of the Combustion chamber facing recess is arranged in which an auxiliary piston is applied force in the direction of the combustion chamber is movably arranged.

The salient advantage of the diesel engine according to the invention compared to the known engines it can be seen that in the combustion chamber during the entire combustion process - even at the moment of ignition - the pressure is always the same, namely the pressure that is due to the compression ratio in the upper pressure point of the piston on The end of the compression stroke is reached. As a result, the diesel engine according to the invention is extremely soft Corridor. Furthermore, there is no peak load on the bearings and moving parts, so that the diesel engine of the invention has a long service life.

The force-loaded auxiliary piston has the following function and Working method:

The auxiliary piston, which is under a pressure that just corresponds to the working pressure or is slightly above or possibly also is slightly below. If the pressure now rises towards the end of the compression stroke of the piston due to the ignition of the fuel, this auxiliary piston deviates against it Direction of force back, which increases the volume of the combustion chamber and which immediately lowers the ignition pressure. When the ignition pressure rises above the working pressure, the combustion chamber is enlarged, which lowers the ignition pressure will. It is only necessary that the force with which the auxiliary piston is acted upon, just corresponds to the pressure that

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should not be exceeded within the combustion chamber. Thus, with the diesel engine according to the invention, an excellent Light pressure combustion can be achieved in which the pressure is constant during the entire combustion process and peak pressures do not occur.

In an embodiment of the invention, the recess can have a bore within the end of the combustion chamber facing Be working piston, with a compression spring within the bore is arranged on which the auxiliary piston rests slidingly. Furthermore, the auxiliary piston can be a recess or boring be a pressure-tight sealing membrane »which is elastic and stretchable.

In a preferred embodiment of the invention, the cylinder can be a double cylinder rotating about a central axis be with co-rotating, fixed working pistons, each one in its end facing the combustion chamber Have bore in each of which an auxiliary piston is displaceably arranged subject to centrifugal force. This embodiment has the salient advantage that the necessary Compressive force for the auxiliary piston is generated by generating centrifugal forces. Any pressure generating means such as There is no need for springs or gas volumes for the auxiliary piston.

Furthermore, an injection piston can be arranged within the auxiliary piston, each of which has one fuel for each ear, which penetrate the working pistons and protrude to the central shaft, which has a central fuel supply, the other end of the fuel tubes protruding through an opening within the bottom of the auxiliary pistons. The injection piston can also be displaceably arranged and each has a guide within each bore of the auxiliary piston have, wherein the guides are connected to one another by means of connecting rods.

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This last-mentioned embodiment of the invention makes an injection pump is superfluous and regulates beyond that the number of revolutions with the engine self-priming.

The invention provides a compression ignition engine available as a two-stroke or four-stroke engine can work. The pressure does not change during the entire combustion process; it cannot be increased by the compression ratio given pressure. This reduces the load on the bearings and the cylinder walls. Further a lower temperature increase in the top dead center is thereby achieved, resulting in less cooling of the Cylinder and the entire engine is necessary. Furthermore, the pressure is maintained longer because the auxiliary piston when the pressure drops, its kinetic energy returns and the combustion chamber volume despite receding Working piston remains relatively the same size for a long time. As a result, the engine according to the invention has also better efficiency. In addition, there is less noise, so that diesel-usual "nails" falls away. In addition, the constant pressure to separate the fuel particles are better burned completely, so that there is less environmental pollution.

The rotating embodiment also has the advantage that it works practically vibration-free and can have a very constant speed.

The engine according to the invention consists of very few components and has a very small construction volume and thus a low power-to-weight ratio.

The invention is based on the description below

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of the embodiments shown in the drawing explained. Show it:

Figure 1 shows a basic embodiment of the invention Internal combustion engine In section, the auxiliary piston being designed as a membrane that is under pressure

FIG. 2 shows a basic illustration of a further internal combustion engine in section, the auxiliary piston being spring-loaded

FIG. 3 shows a cross section through a double cylinder rotary engine with rotating, fixed working piston

Figure Ί a detail from Figure 3, namely the injection piston,

FIG. 5 shows an enlarged cross section through the central shaft to illustrate the fuel supply through the same and

Figure 6 shows a further cross section through the central shaft for Representation of the return channels for excess Fuel.

The internal combustion engine shown in Figure 1 consists of a cylinder 1 in which a reciprocating piston 2 is displaceably arranged is. The cylinder 1 and the reciprocating piston 2 are suitably mounted in a known manner on the engine block (not shown). The reciprocating piston 2 forms the combustion chamber 3 in the top dead center opposite the wall of the cylinder 1. The reciprocating piston 2 now has a bore 5 at its upper end facing the combustion chamber 3, which is preferably made by means of a membrane a rigid metal membrane, closed 1st. The metal membrane is elastic and somewhat stretchable. the

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Bore 5 is under gas pressure, which is the same or slightly less the work pressure is. The membrane is stiff but flexible. If the pressure now rises above the working pressure during ignition - and thus via the gas pressure within the closed Bore 5 - this is how the membrane M is moved into the bore 5, whereby the gas pressure inside the combustion chamber 3 is lowered by increasing the volume.

FIG. 2 shows a cylinder 6 in which a reciprocating piston 7 is also displaceably arranged. Cylinder 6 and reciprocating piston 7 are in turn suitable in a known manner on one Engine block supported. At top dead center, the reciprocating piston 7 forms a combustion chamber 8 with the wall of the cylinder 6.

A blind hole 9 is drilled inside the reciprocating piston 7, in which an auxiliary piston Io is displaceably arranged. Between the auxiliary piston Io and the bottom of the bore 9 is a compression spring 12, which moves the piston upward in the direction of Combustion chamber presses. At the upper edge of the bore 9 a circumferential annular flange 13 is attached, which with a shoulder 14 of the auxiliary piston Io cooperates, so that the auxiliary piston Io is supported by the plan 13 within the bore 9.

The Arbeltprinzip again corresponds to that of Figure 1: If the ignition pressure rises above the respective working pressure, the auxiliary piston Io moves with the corresponding Spring constant s inwards, whereby the ignition pressure due to The increase in volume of the combustion chamber drops immediately. During the downward movement of the reciprocating piston 7, the auxiliary piston now returns the energy stored in the compression spring in accordance with the decrease in pressure within the combustion chamber, thereby giving up the volume increase in the combustion chamber The return movement of the reciprocating piston 7 is reduced. Through this

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the working pressure is maintained for a longer period of time.

The auxiliary piston is also an energy storage piston, which absorbs the excess energy generated according to the working pressure and this in the course and towards the end of the combustion process in turn delivers to the reciprocating piston.

Figure 3 shows in section a rotary double cylinder engine, consisting of two reciprocating cylinders 15 * 16 which compared to the fixed working piston 25, 26 in the upper Form dead points combustion chambers 17, 18. A central wave is in the geometric center line of the two working pistons 25t 26 arranged, the central shaft 27 of two Parts 62, 63 consists. The cylinders 15, 16 rotate around the Central shaft 27, on the part 62 of which the two working pistons 25, 26 are firmly attached. The other part 63 of the medium wave 27 is certain; around it rotate working piston and cylinder, which are attached to connecting rods 19, 2o, 21, 22, the Can be rings that run on connecting rod bearings 23, 21. With the reference numerals 23 and 24 should also be the engine block at the same time and the suspension of the same be marked, both of which are not shown in detail. The whole system rotates around the central shaft 27, the cylinders 15, 16 reciprocating. The engine is designed as a two-stroke engine.

Within the working piston 25, 26 there is a blind hole each 28, 29 are drilled, each with an aid or storage piston 3o, 31 is movably arranged. The working pistons 25, 26 each have a central bore 32, 33, as do the auxiliary pistons 3o, 31 each have a bore 38, 39. In the bores 38, 39 of the auxiliary piston 3o, 31 and the bores 32, 33, the working piston 25, 26, an injection piston 6o is arranged, which is shown in more detail in FIG.

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The injection piston 60 consists of two fuel pipes 30, 35, which are each held in a guide 36, 37. The guides 36, 37 are connected to one another by connecting rods 51, 52 to form a rigid structure. Within the fuel tubes 3 ¹ J, 35 fuel channels 43, 44 are arranged, which open into outlet openings 45, 46 at the upper ends of the fuel tubes 34, 35. The guides 36, 37 of the injection piston 60 are guided in the bores 38, 39 of the auxiliary piston 3o, 31, the fuel tube 34, 35 protrude through the bores 32, 33 of the working piston 25, 26 and reach down to the fixed part 63 of the central shaft 27, in which a central fuel guide 42 is arranged.

FIG. 5 shows in cross section the central shaft part 63, in which is centrally located the fuel channel 42. At the level of the fuel pipes 34,35 of the double injection piston 60 has the part 63 has a diameter bore 54. This diameter bore 54 is in communication with the fuel channel 42 and serves to supply fuel to the injection piston 60. The channel 54 has a slot-shaped, elongated recess 55, which during the injection of the fuel of the opposite working piston sucks in fuel with respect to the working piston that is sucking in during a certain period of the exhaust stroke of the same. The diameter bore 54 has a half 53 which terminates of the injection process by returning any remaining fuel within the fuel channel 42 serves. The fuel channel is in this embodiment pressureless.

FIG. 6 shows a further cross section through the part 63 of the central shaft 27 at the level of the return conduits 57 »58 of the Figure 3o these return channels 57, 58 open into a Annular groove 56, which in turn via a radially extending return channel 59 within the part 63 into the fuel channel 42 opens. The annular groove is arranged circumferentially on the outer surface of the part 63. The return channels

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57, 58 extend from the ends facing the part 63 the working piston 25, 26 in the vicinity of the mouths of the Through bores 32,33 within the working piston to the through bores 32, 33 · The return ducts 57, 58 serve to return fuel, which due to the self-generated high injection pressure into the Through bores 32, 33 could have emerged »On the upper edge within the recesses 28, 29 of the working pistons 25, 26, annular flanges 40, 61 are attached to limit serve to move the storage piston 3o, 31 radially outward when the engine rotates. The accumulator pistons point one shoulder 41 each, which bear against the annular flanges 4o, 61 at the top dead center of the accumulator pistons 3o, 31. The working pistons are against the cylinder, the storage piston against the bores 28,29 within the working ^ piston and the Injection piston guided pressure-tight against the storage piston. With the reference numerals 47, 48, 49 and 5o in Figure 3 are inlet and outlet openings marked for the air entering and the combusted gases exiting.

The operation of the motor shown in Figures 3-6 is as follows:

The cylinders 15, 16, the working pistons 25, 26 and the storage pistons 3o, 31 revolve around the rotating central shaft 27, the part 62 of which rotates with it and the force-emitting end of the Forms medium wave and the part 63 is fixed. The storage pistons 3o, 31 move due to the centrifugal forces moved outside, which is why the accumulator piston is close to top dead center (just before the fuel self-ignites) generate an absolutely constant pressure at constant speed. The air inside the combustion chamber is now up to reaching the top dead center further compressed. The compression volume can be designed so that the storage piston due to the increase in pressure, it is moved back in the direction of the center shaft before the top dead center is reached 27. Now the accumulator piston moves inwards

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back, then the outlet opening 45 or 46 of the fuel channel 44 and 43 of the double injection piston released.

The fuel supply is self-priming, i.e. that the Fuel channel 42 is not under injection pressure, but is pressureless. During the expulsion of the burnt gases from the combustion chamber of a working piston or cylinder Its storage piston moves together with the injection double piston due to the centrifugal forces outside, whereby this working piston sucks in fuel. The other working piston is currently working in the compression stroke, whereby the storage piston moves this working piston back inward. Due to the further rotation of the working piston, the fuel supply 54 is now within the Part 63 of the central shaft 27 closed. The accumulator piston moves back together with the injection double piston, whereby within the fuel channels 43 and 44 of the double injection piston a high pressure of the fuel is built up. If the accumulator piston continues to move back the outlet opening 45 or 46 of the fuel channel is finally released. Because of the high pressure arises within the fuel channel and due to the very small exit opening areas of the exit openings 45, 46 a sufficiently high injection pressure of the fuel, whereby the combustion is initiated. This enlarged the gas volume and the storage piston recede accordingly. There is therefore no pressure increase in the combustion chamber instead, the maximum pressure is only dependent on the centrifugal forces that act on the storage piston and thus on the speed of the engine.

By reducing the diesel supply available for injection, the injection piston also gives way Direction towards the central shaft 27 back. By suitable choice of the fuel pipe diameter and cross-section

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of the outlet openings 45, 46, the retraction of the injection piston 6o can be selected so that during the volume η would increase the storage piston and the injection piston retreat synchronously, whereby a constant injection pressure is maintained.

The injection is terminated when the outlet openings 45, 46 within the bores in the storage piston 3o, 31 come to rest.

The cylinder and the working piston now gradually move away from each other as the engine rotates. Behind the top dead center, which is, for example, lo ° -2o ° behind TDC. can be, the storage piston meets the one holding it ■ Ring flange 40, 61 on. Be from the start of the fuel injection until it hits the storage piston The abutment has always been under constant pressure. Now the pressure decreases as the cylinder is further removed from top dead center, the burnt gases are expelled and fresh air is sucked in.

Since the fuel pipes 34, 35 and the guides 36, 37 with each other are connected by connecting rods 51, 52 and thus form the injection double piston moves this slightly towards the other cylinder, so that now fuel from the fuel pipe from the channel widening is on this other side is sucked in. This channel widening is advantageous because the fuel intake, as explained above, is done with negative pressure and therefore a certain time is required for this.

In addition, the internal combustion engine according to the invention has the tendency to reduce its working speed due to the above-described Regulate injection yourself.

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The combustion chamber extension takes place near the upper one Dead center instead. This means that even a slight change in pressure caused by the accumulator piston is a significant one Postponement of the start of injection has the consequence. If the speed increases due to decreasing load, then increase it the centrifugal forces acting on the accumulator pistons; the same "press" more outwards. This will make the Outlet openings of the fuel channels exposed later. If this was the case at high load, e.g. lo ° before top dead center, the fuel is injected now only e.g. 3 before top dead center, when the speed has increased. But this is the end of the injection due to the appropriate design of the radial fuel channel 53 set to e.g. 2 ° after top dead center, this reduces the amount of fuel injected, thus the power is throttled and the speed is reduced. Because the half 53 of the fuel channel 54 is used by Druckwegnähme to terminate the injection. For the correct choice of this point in time, the angle between the one radial The fuel channel 54 and the bore 53 can be selected as desired.

This embodiment is therefore particularly suitable for Motors that run at constant speed, e.g. to drive generators.

In addition, the fuel supply can also have a Pressure pump cannot be self-priming.

The internal combustion engine according to the invention shown in FIG. 3 can also be designed as a four-stroke engine. Likewise, the number of cylinders can be other than two as shown Be an example.

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Claims (6)

- ir - Claims (! • / ^ internal combustion engine with compression ignition, with at least one cylinder with combustion chamber and working piston and an injection device, characterized in that one of the combustion chambers (3, 8, 17, 18) facing recess (5,9,28,29) is arranged, in which an auxiliary piston (4, Io, 3ο, 31) is arranged movably in the direction of the combustion chamber, acted upon by force. 2. Internal combustion engine according to claim 1, characterized in that the recess is a bore (9) within the end of the working piston (7) facing the combustion chamber (8), a compression spring (12) being arranged within the bore (9) which the auxiliary piston (lo) rests on. 3. Internal combustion engine according to claim 1, characterized in that the auxiliary piston is an elastic, stretchable membrane (4) which closes off the recess (5) in a pressure-tight manner, 4. Internal combustion engine according to claim 1, characterized in that the cylinder is a double cylinder (15, 16) rotating about a central shaft (27) with a co-rotating, fixed working piston (25, 26) which faces in its combustion chamber (17, 18) Each end has a bore (28, 29), in each of which an auxiliary piston (3o, 31) is displaceably arranged, subject to the flow of air. 5. Internal combustion engine according to claim 4, characterized in that an injection piston (6o) is arranged within the auxiliary piston (3o, 31), each having a combustion 809848/0034 material pipe (34,35), which penetrate the working piston (25,26) and protrude to the central shaft (27), which has a central fuel supply (42), the other end of the fuel pipes (34,35) through an opening within the bottom of the auxiliary piston protrudes. 6. Internal combustion engine according to claim 5, characterized in that the injection piston (6o) is displaceably arranged and each has a guide (36,37) in the region of the upper ends of the fuel pipes (34,35) within a respective bore (38,39) of the Auxiliary piston (3o, 31), the guides being connected to one another by means of connecting rods (51, 52). 809848/0034