EP1961943A1 - Combustion engine - Google Patents

Abstract

The internal combustion engine has a cylinder, which is operated when fuel is supplied. Another cylinder is operated without a separate supply of the fuel. An overflow connection (20) is formed between the cylinders and is fitted with blocking units (22,23), which are maintained in an open position during a power stroke of the former cylinder. The pistons (10,11,12) in the cylinders move in a synchronous manner in relation to a top and bottom dead centers. A dead volume (17) of the latter cylinder is smaller than the dead volumes (15,16) of the former cylinder.

Description

The invention relates to an internal combustion engine specified in the preamble of claim 1. Art.

Four-stroke or two-stroke internal combustion engines are known with any number of cylinders, with each cylinder operating separately from the adjacent one and operating either at every fourth stroke or at every other stroke utilizing the combustible air / fuel mixture burned. The efficiencies of such internal combustion engines are limited and are for example about 25% in gasoline engines and about 40% in diesel engines. Despite permanent developments, only marginal improvements in efficiency have so far been achieved. One reason for the relatively poor efficiency is the incomplete expansion of the combusted mixture, the high exhaust gas temperature, and a non-ideal combustion characteristic. Even with the high residual pressure operated auxiliary devices such as turbochargers could not cause sudden improvements, and possibly increase the thermal load of the internal combustion engine inappropriate.

The invention is based on the object to provide an internal combustion engine of the type mentioned, which operates with significantly improved efficiency and is compact.

The stated object is achieved with the features of claim 1.

The high-energy engine as a combination of a four-stroke and a two-stroke engine operates with three cylinders such as a four-cylinder engine, six cylinders such as an eight-cylinder engine, etc., wherein the middle piston in the cylinder performs a nearly total expansion of the combustion pressure to convert into mechanical energy directly in the engine. This almost total expansion reduces the temperature in the exhaust gas, resulting in addition in a very low thermal load of the engine, which requires little or no cooling energy and increases the power output. The basic module can be combined with other such basic modules almost arbitrarily, which can be based on the three-row bank boxer, series, V, W or star arrangements can be realized. Since the basic module with three cylinders, like a four-cylinder engine works, can be especially axial realize very compact motor dimensions. The reciprocating piston work parallel to each other, possibly with identical strokes. Thanks to the significantly smaller dead volume in the middle cylinder, the piston in the middle cylinder needs much less energy to finally compress to the same pressure as any cylinder next to it during the combined expulsion and compression stroke. As soon as pressure equality is achieved before ignition, the overflow connection is opened, whereby thanks to the pressure equilibrium initially no noticeable overflow takes place. After ignition in the outer cylinder, the combustion pressure, which acts on the reciprocating piston in the outer cylinder directly and via the overflow now also the reciprocating piston in the middle cylinder, so that both reciprocating perform a power stroke. Since then the additional volume in the middle cylinder is available for the expansion of the working pressure, the combustion pressure can be almost completely expand, ideally to the atmospheric pressure, thanks to the expansion, the temperature is significantly reduced when the two reciprocating reach their bottom dead centers , In the other outer cylinder, an intake stroke has been performed at the same time. After the recent reversal of motion of all reciprocating piston cooperates with the middle cylinder of the other outer cylinder in the manner described above.

Suitably, the stroke of the middle piston is different from the strokes of the outer piston. Thus, for example, form a large expansion space without enlarged middle piston, which keeps the axial dimensions low.

Suitably, the connecting rod angle of the middle piston is different from those of the outer piston. Then, the middle reciprocating piston reaches its dead center forward or backward, e.g. to account for a delay in ignition.

In an expedient embodiment, the two outer cylinders have inlet and outlet valves, while the middle cylinder has at least one outlet valve. This exhaust valve is used to exhaust expanded and relatively cool exhaust gas from the middle cylinder. Since the middle cylinder operates in two-stroke mode, the exhaust valve is opened only over part of the Ausschiebe- and compression stroke to build up in the smaller dead space of the middle cylinder up to a certain stroke position the same pressure in the outer, just the compression stroke exporting cylinder is reached until the overflow connection is opened.

In an expedient embodiment, the shut-off member of the overflow connection is a slide or a piston valve. Both the slider and the piston valve avoid in the shut-off an undesirable dead space.

According to another important aspect, the middle cylinder has a larger cylinder diameter than the two outer cylinders. This increases the usable space for expansion and also the loading surface of the reciprocating piston during the power stroke.

Suitably, the working cycles of the two outer cylinders are offset from each other by 360 degrees of the crankshaft rotation angle. In this way, the middle cylinder ideally works alternately with each outer cylinder at its stroke.

Another important aspect is that the exhaust valve of the middle cylinder during the Ausschiebe- and compression stroke of the reciprocating piston is aufsteuerbar only between the bottom dead center and a predetermined stroke position below the top dead center. As long as the exhaust valve is open, expanded cool exhaust gas is expelled. The closing time of the exhaust valve is chosen so that in the middle cylinder after closing the exhaust valve shortly before reaching the top dead center because of the smaller dead space, the same pressure prevails as in the outer, just the compression stroke exporting cylinder.

In order to improve the degree of filling in each cylinder, it is expedient if the internal combustion engine has a charging device.

It is particularly useful thanks to the parallel movement of the reciprocating piston of the basic module whose crankcase is used as a charge pump. The loading device may, preferably, be used primarily for loading the middle cylinder, whereby then a loading ratio of about 1: 3 can be achieved. For this purpose, it is advantageous to provide in the middle cylinder at least one positively controlled inlet valve, via which the cylinder can be connected to a fuel-free charge air supply.

Here, the inlet valve serves as a purge valve during the Ausschiebe- and compression stroke in the middle cylinder, and that at least until the closing of the exhaust valve. It is supported in this way by the supply of fresh air, the pushing out of the exhaust gas, and kept ready for the subsequent power stroke in the middle cylinder fresh air, which is useful for a proper post-combustion of fuel from the outer cylinder.

This post-combustion runs relatively lean and at high temperature, which increases the power output. This residual fuel from the outer cylinder could hardly be completely burned in the outer cylinder itself. Another advantage of the charge air supply at least to the middle cylinder is a desirable temperature reduction, optionally when using a charge air cooler.

In an expedient embodiment, the basic module as gasoline or gas engine ignition devices only for the two outer cylinder, and of course only fuel supply devices for these two outer cylinder.

In another expedient embodiment, the base module as a diesel engine on Glühvorrichtungen and Brennstoffzuführvorrichtungen only for the two outer cylinder. This reduced equipment reduces manufacturing costs and weight in both cases.

In an advantageous embodiment, the reciprocating piston of the middle cylinder at the same cylinder heights on a dead space in the middle cylinder reducing, raised piston crown.

Since the middle piston exerts relatively high force on the crankshaft in its more frequent work cycles, it is expedient to store the crankshaft between the crank pin for the three reciprocating piston and to strengthen the connecting rod of the middle piston.

Also useful are the valves or sliders camshaft actuated to achieve precise timing dependent on the crankshaft rotation.

Fig. 1

einen Längsschnitt durch ein Grundmodul des Brennkraftmotors,

Fig. 2

eine vergrößerte Detailvariante des Brennkraftmotors im Zylinderkopfbereich, und

Fig. 3

eine weitere Ausführungsform des Brennkraftmotors bestehend aus zwei Grundmodulen im Boxeranordnung.

Embodiments of the subject invention will be explained with reference to the drawing.
Show it:

Fig. 1

a longitudinal section through a basic module of the internal combustion engine,

Fig. 2

an enlarged detail variant of the internal combustion engine in the cylinder head area, and

Fig. 3

a further embodiment of the internal combustion engine consisting of two basic modules in the boxer arrangement.

An in Fig. 1 shown internal combustion engine M is either a gasoline or gas (hydrogen) or a diesel engine and has as basic module A three cylinders in a cylinder bank 2 of a motor housing 1 with a crank chamber 3. In each cylinder, a reciprocating piston 10, 11, 12 included, wherein, preferably, the cylinder and piston diameter in the middle cylinder is greater than in the two outer cylinders. The reciprocating pistons 10, 11, 12 are connected via connecting rods 9 with crankpins 5a, 5b, 5c of a crankshaft 4. The connecting rod 9 of the middle reciprocating piston 12 could be reinforced or stronger than the others. The crank pins 5a, 5b, 5c are located in a common, parallel to the axis of the crankshaft 4 axis 6, so that the reciprocating pistons 10, 11, 12, move parallel to each other.

The two outer cylinders operate in four-stroke mode, while the middle cylinder operates in two-stroke mode. The crankshaft 4 is mounted at its ends in bearings 7 and also between the crank pin 5a, 5b, 5c, in bearings 8. In a cylinder head 13, intake and exhaust valves 18 are provided for the two outer cylinders which are positively controlled (eg by at least one camshaft, not shown). The two outer cylinders also each have at least one ignition device or annealing device 19 and also each a fuel supply device (not shown), which operates for example with fuel injection. Various popular injection methods can be used here. A fuel supply via carburetor is possible. The middle cylinder has at least one outlet valve 27, which is positively controlled. In the illustrated embodiment of the basic module A, at least one positively controlled inlet valve 28 is further provided in the middle cylinder. This intake valve is not absolutely necessary, but it is useful if the engine M is operated, for example, with a charging device.

Since the basic module is operated with a reciprocating piston operating in parallel, considerable pressure pulses are generated in the crank chamber 3, so that the crank chamber 3 can be usefully used as a charging pump of the charging device to charge at least the middle cylinder via the inlet valve 28. For this purpose, inlet can be used - And outlet means 25, 26 may be provided for the crank chamber 3, wherein said outlet device is then connected at least to the inlet valve 28.

The dead spaces of the two outer cylinders are indicated by 15 and 16. The dead space 17 of the middle cylinder is considerably smaller than the dead spaces 15, 16. This is achieved, for example, that the reciprocating piston 12 in the middle cylinder a raised piston crown 14 and / or due to the different stroke of the lifting cylinder 12 or with a different connecting rod angle of the connecting rod 9 of the middle piston 12 relative to the other connecting rods 9. A significantly larger cylinder or piston diameter of the middle cylinder leads to a better power yield and energy conservation.

Between the dead space 15 or 16 of each outer cylinder and the dead space 17 of the middle cylinder overflow 20, 21 are provided, which are each opened and closed by a positively controlled shut-off G. In the in Fig. 1 basic module A shown are the shut-off G slider 22, 23 which are arranged in the cylinder head 13 slidably approximately parallel to the stroke direction of the reciprocating piston. Between the crank pin 5a, 5b, 5c balancing weights 24 may be arranged on the crankshaft 4.

Function:

The in Fig. 1 Hub piston 10 shown on the left executes four strokes over a crankshaft rotation angle of 720 degrees. The first cycle is the intake stroke with movement from top dead center to bottom dead center with the intake valve open and the exhaust valve closed. The second cycle is a compression stroke in which the reciprocating piston 10 moves from bottom dead center to top dead center, with intake and exhaust valves closed. At the end of the compression stroke, the ignition takes place. The third cycle is a power stroke in which the reciprocating piston 10 moves from top dead center to bottom dead center with the inlet and exhaust valves closed. The fourth clock is a Ausschiebetakt in which the reciprocating piston 10 moves from bottom dead center to top dead center, and in which the exhaust valve is opened and the inlet valve is closed.

The in Fig. 1 Right hand piston 11 performs its four strokes with a 360 degree offset against the clocks of the left cylinder.

While in Fig. 1 left reciprocating 10 performs its intake stroke, the overflow 20 is closed, however, the overflow 21 open. The middle piston 12 cooperates with the right-hand piston 11, to the effect that the combustion pressure from the in Fig. 1 right cylinder acts on the overflow 21 and the middle piston 12, the output power to the crankshaft 4. In the middle cylinder, the exhaust valve is closed during this power stroke, and if present, also the inlet valve 27.

During the compression stroke of the left-hand reciprocating piston 10, the outlet valve 27 of the middle cylinder is opened from the bottom dead center, as is the outlet valve of the in-cylinder Fig. 1 right cylinder. The exhaust gases are ejected. Depending on the size of the dead space 17 and its ratio to the dead space 15, the exhaust valve 27 of the middle cylinder is closed from about 45 degrees crankshaft rotation angle before top dead center. The middle piston 12 then begins to compress, since both shut-off members G are in the closed position. As soon as the pressures in the dead spaces 15, 17 are the same, the slide 22 is opened, approximately with the ignition in the left outer cylinder, or forward or retarding to the ignition. The combustion pressure in the Fig. 1 The left cylinder now also acts on the middle piston 12, which transmits power to the crankshaft 4 and above all provides additional expansion volume to totally or almost totally expand the combustion pressure until it is close to atmospheric pressure.

If the engine M has a supercharger and the intake valve 27 is provided in the middle cylinder, the intake valve is opened during the compression and exhaust stroke of the middle piston 12, even though the exhaust valve 27 is open. For example, the intake valve is opened about 45 degrees crankshaft rotation angle after the bottom dead center and closed in approximately concurrent with the exhaust valve 27, d. h, at about 45 degrees before top dead center. As a result, fuel-free fresh air is introduced into the middle cylinder to expel (purge) the exhaust gas and introduce fresh air. This fresh air can be used for afterburning of fuel from the in Fig. 1 be used left cylinder, this post-combustion runs lean and high temperature, ie a favorable power yield allows.

When the bottom dead center is reached, both slides 22, 23 are closed. The in Fig. 1 left piston 10 then performs its Ausschiebetakt, while in Fig. 1 right lifting piston 11 performs its compression stroke until the in Fig. 1 right slide 23 is opened again.

Thus, each outer reciprocating piston 10, 11 performs a power stroke at every third clock, while the middle reciprocating piston 12 performs a power stroke every second clock.

The embodiment in Fig. 2 is different from that of Fig. 1 by a different design of the shut-off members G. Instead of the slide 22, 23 piston valves 31, 32 are used here, which are guided displaceably in the cylinder head 13. Each piston valve has a Valve plate 31 and an actuating piston 32. For the valve plate 31, two spaced valve seats 30 and 29 or 34 and 33 are provided in the overflow connection 20, 21. The design of the piston valve avoids in the closed position an inappropriate dead space. Furthermore, the piston valve located in the closed position (in Fig. 2 right) held by the combustion pressure in close contact with its valve seat 33. This avoids leakage.

Fig. 3 shows an internal combustion engine M, which is composed of two basic modules A, forming a 180 ° -Boxeranordnung. In addition to the crankpins 5a, 5b, 5c, the crankshaft 4 'in the crankcase 3a has crankshaft journals 5d, 5e and 5f offset by 180 degrees about the crankshaft axis for the three other reciprocating pistons of the lower basic module A. The firing order can be crossed or directly opposite one another. Also in this internal combustion engine M, the crank chamber in the crankcase 3 can be used as a charging pump of a charging device, or supplement a charging device, if the working in four-stroke cycle cylinder are operated with charge.

Since in the ideal case a total expansion of the combustion pressure with direct conversion into mechanical energy in the engine itself can be achieved, the exhaust gas pressure and the exhaust gas temperature are low. The internal combustion engine can be operated with low thermal load, i. It hardly needs cooling power in operation, rather even good thermal insulation. There is hardly any residual pressure wasted, which relieves the exhaust system. Especially with the charge and the inlet valve 27, the energy contained in the fuel is better utilized. If necessary, a small catalyst is sufficient to meet the exhaust gas regulations, or a catalyst is completely unnecessary (or a soot filter). Since the basic module with three reciprocating pistons already works like a four-cylinder in series, and also delivers corresponding power, compact dimensions can be achieved at least in the direction of the crankshaft axis, and the weight of the internal combustion engine can be reduced. With test engines built and operated, an efficiency of about 50% or more could be achieved compared to conventional power-like engines, with reduced weight and smaller dimensions and with lower specific fuel consumption.

Claims (18)

Internal combustion engine (M) with at least three reciprocating pistons (10, 11, 12) which are coupled to a crankshaft (4, 4a) in at least one cylinder bank (2) via connecting rods (9), with positively controlled cylinder gas exchange valves (18, 27, 28), with fuel supply and Abgasabführeinrichtungen, characterized in that the internal combustion engine (M) is a high-energy motor with the three-row bank (2) as a basic module and with at least one other such basic module in the boxer, row, V, W or star Arrangement can be combined,
of the three cylinders with the parallel reciprocating pistons (10, 11, 12), the two outer (10, 11) with fuel supply in the four-stroke process and the middle piston (12) with a substantially smaller dead volume (17) in the middle cylinder than for the two Reciprocating piston (10, 11) are operable in the outer cylinder and without its own fuel supply in the two-stroke process,
the three crankshaft journals (5a, 5b, 5c) of the three reciprocating pistons lie in an at least substantially common axis (6) parallel to the crankshaft axis,
and between each outer cylinder and the middle cylinder in the upper Hubkolbentopfpunktbereich an overflow connection (20, 21) is provided with a positively controlled shut-off (G), which is only on reaching pressure equality between the one in each compression cylinder outer cylinder and the middle cylinder aufsteubar and maximum until the end of the following power stroke in this outer cylinder and the middle cylinder in the open position is durable. Internal combustion engine according to claim 1, characterized in that the three reciprocating pistons (10, 11, 12) have identical strokes. Internal combustion engine according to claim 1, characterized in that the stroke of the middle piston (12) is different from the identical strokes of the two outer piston (11, 13). Internal combustion engine according to claim 1, characterized in that the connecting rod angle of the connecting rod (9) of the middle piston (12) is slightly different from the connecting rods of the connecting rod of the two outer piston (11, 13). Internal combustion engine according to claim 1, characterized in that the outer cylinder intake and exhaust valves (18) and the middle cylinder at least one exhaust valve (27). Internal combustion engine according to claim 1, characterized in that the shut-off member (G) of the overflow connection (20, 21) is a slide (22) or a piston valve (31, 32). Internal combustion engine according to claim 1, characterized in that the central cylinder has a larger cylinder diameter than the two outer cylinders. Internal combustion engine according to claim 1, characterized in that the working cycles of the two outer cylinders are offset by 360 degrees of the crankshaft rotation angle to each other. Internal combustion engine according to claim 5, characterized in that the exhaust valve (27) of the middle cylinder during the Ausschiebe- and compression stroke of its reciprocating piston (12) only between the bottom dead center and a predetermined stroke position below the top dead center, preferably at about 45 degrees crankshaft angle before top dead center, is aufsteuerbar. Internal combustion engine according to claim 1, characterized in that a charging device is provided. Internal combustion engine according to claim 10, characterized in that the charging device comprises the crankcase (3, 3a) as a charge pump. Internal combustion engine according to claim 10, characterized in that the middle cylinder additionally has at least one inlet valve (28) via which the middle cylinder can be connected to a fuel-free charge air supply. Internal combustion engine according to claim 12, characterized in that the inlet valve (28) of the middle cylinder as a purge valve during the Ausschiebe- and compression stroke in the middle cylinder at least until closing of the exhaust valve (27) aufsteuerbar, preferably from about 45 degrees crankshaft rotation angle after the bottom dead center. Internal combustion engine according to claim 1, characterized in that the basic module (A) as gasoline or gas engine ignition devices (19) only for the two outer cylinder. Internal combustion engine according to claim 1, characterized in that the basic module has as a diesel engine annealing devices (19) only for the two outer cylinders. Internal combustion engine according to claim 1, characterized in that the reciprocating piston (12) of the middle cylinder at the same cylinder heights has a dead space (17) reducing, raised piston head (14). Internal combustion engine according to claim 1, characterized in that the crankshaft (4, 4 ') is also mounted between the connecting rod crankpins (5a, 5b, 5c). Internal combustion engine according to at least one of the preceding claims, characterized in that the valves (18, 27, 28, 31, 32) and the slide (22) via the crankshaft (4, 4a) are camshaft actuated.

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