DE2747884A1 - IC engine cam timing modification system - uses pulleys on sliding arms to vary effective length of drive belt - Google Patents

Abstract

The performance of an internal combustion engine is improved by modifying the timing sequence for entry of gases into the combustion chamber by altering the position of the cams. The belt (40) which is driven by the crankshaft (38) and which drives the camshaft (42) also passes over an adjusting roller (46). This is in line with a tensioning roller (48). The latter is mounted on an arm (52) with a spring (54) behind it, able to slide inside a lever (50) which carries the adjusting roller (46). The movement of the lever (50) to and fro is controlled by the accelerator pedal. This varies the effective length of the belt.

Description

AUDI NSU AUTO UNION 8O7O Ingolstadt, October 14, 1977

Aktiengesellschaft IP 14-91 Dr.Ba/L

P.O. Box 220
8O7O Ingolstadt

Process tin controlling the operation of an internal combustion engine, as well as internal combustion engine operating according to the method

The invention relates to a method for controlling the operation of an internal combustion engine, in particular for passenger cars, with at least one piston-cylinder unit, its working chamber is connected to an intake manifold through an inlet in which an inlet valve is arranged, the opening time of which, based on the suction stroke of the piston, with decreasing power to be delivered by the internal combustion engine, is shifted to late.

The invention further relates to an internal combustion engine operating according to the method with at least one piston-cylinder unit, whose working chamber is connected to a suction pipe through an inlet in which an inlet valve is arranged which is operated by a rotatable intake cam driven by a crankshaft cooperating with the piston is.

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Various methods are known for controlling the operation of internal combustion engines, in particular of passenger cars .

The most common today is the method in which a throttle valve is arranged at the inlet of the intake manifold and determines the effective inlet cross-section of the intake manifold. When the throttle valve is closed, this inlet cross-section is small; there is only a little fresh air or, in the case of one upstream of the intake manifold Carburetor, mixture, are sucked in. If the throttle valve is open, there will be a lot with a suction stroke of the piston Fresh air or mixture sucked in; the power output by the internal combustion engine increases. From an energetic point of view, When the throttle valve is closed, the energy consumed by the piston during the intake stroke is used to create a negative pressure in the intake manifold build up and by means of this negative pressure on the throttle valve to suck in fresh air or mixture past, this mixture in the area of the inlet narrowed by the throttle valve is swirled in the intake manifold, but this turbulence is then in the further course of the relatively long intake manifold calm again.

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From the DT-AS 17 51 44-9 is known to control the of the Internal combustion engine output power to change the lift of the inlet valves, with the decreasing lift of the internal combustion engine output decreases. This control method has the advantage that as the lift of the intake valve decreases The mixture sucked into the working chamber is more turbulent through the narrowed inlet cross-section and this turbulence stops in the working chamber immediately adjacent to the valve, which means that lean mixtures can be used. Additionally the mixture burns faster so that the ignition point can be delayed.

From DT-PS 809 613 it is known to control a mixture-compressing internal combustion engine in such a way that the sucked in, constant mixture volume depending on the power to be delivered a larger or smaller part at the beginning of the compression stroke * is pushed back into the suction pipe, while the rest is compressed and burned in the working chamber. In this procedure the time at which the inlet valve opens remains constant, while the time at which the inlet valve closes with decreasing power to be delivered, increasingly relocated to the area of the compression stroke of the piston following the suction stroke will.

* and inlet valve still open

** then after closing the inlet valve

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From DT-OS 20 06 304 a control method is known in which the inlet valve for the purpose of improving the mixture preparation with decreasing output from the internal combustion engine Power closer to the point in time at which the piston has maximum speed during its suction stroke. That The inlet valve thus opens at a point in time when there is a strong negative pressure in the working chamber in which the piston is working prevails, so that the mixture is sucked into the working chamber at high speed and is strongly swirled.

A peculiarity of the methods described for controlling operations an internal combustion engine, which with shifting the opening or closing time of the inlet valve or Adjustment of the stroke of the inlet valve work is that relatively complex devices are necessary for this - either an intake cam that controls the intake valve must be constructed in several parts so that the opening time of the intake valve is changeable, or a hydraulic drive of the inlet valve must be provided, which is great structural Effort means.

The invention is based on the object, in its implementation simple method of controlling the operation of a

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Specify internal combustion engine, with which a proper operation sverhal th of the internal combustion engine even when operating with lean mixtures or with a large air-to-fuel ratio is achieved.

This object is achieved according to the invention with a method of the type described at the outset in that the closing time of the inlet valve decreases as the internal combustion engine decreases output to be delivered is also postponed to late, so that it is increasingly in the following on the suction stroke. Compression stroke of the piston.

In the method according to the invention, the constructional outlay is avoided, which is caused by the fact that when changing of the operation of the internal combustion engine to the opening time is moved late while the closing time remains constant or vice versa. The fact that in the method according to the invention the inlet valve is open in partial load operation during part of the suction stroke of the piston and the subsequent compression stroke of the piston, a particularly effective turbulence is of the mixture burned in the working chamber: The inlet valve opens during the suction stroke, only at a large Negative pressure in the working chamber and high piston speed,

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whereby the mixture sucked in through the inlet is immediately put into strong turbulence. The inlet valve then remains open beyond the bottom dead center of the piston, whereupon part of the strongly swirled mixture is pushed out through the inlet into the intake manifold during the subsequent compression stroke of the piston and is there, well prepared, available for the next intake stroke. In the method according to the invention, optimal swirling of the mixture is thus achieved, which enables the internal combustion engine to be operated even with very lean mixtures. The turbulence is particularly intense compared to processes in which only the opening time of the inlet valve is shifted and the closing time remains constant, because the "mixture column" sucked into the working chamber near the bottom dead center of the piston is not squeezed off by a closing inlet valve, which would avoid the formation of pronounced turbulence.

The fact that a throttle valve can be absent in the intake manifold avoids the occurrence of large η negative pressure s in the intake manifold, so that hardly any exhaust gas backflow occurs in internal combustion engines operating according to the method according to the invention. There is also with regard to the design of the intake manifold in multi-cylinder combustion

* in the inlet

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power machines extensive freedom, since it is based on uniform Mixture feed to the individual cylinders or evenly The formation of negative pressure in the intake manifolds leading to the individual cylinders does not arrive in the hatred, as with conventional ones Internal combustion engines.

The one in the working chamber after an exhaust stroke of the internal combustion engine the remaining exhaust gas mixes with the fresh, strongly swirling mixture during the subsequent intake stroke is partially pushed out of the working chamber together with this during partial load operation, so that the ignition readiness of the mixture is only slightly influenced by the exhaust gas remaining in the working chamber.

Due to the strong turbulence, the engine also works in partial load operation with low cyclical fluctuations.

The method is advantageously carried out in such a way that the opening period and the lift of the inlet valve are independent of the service to be submitted.

An internal combustion engine of the type described at the beginning is characterized according to the invention by a device for adjusting the angular association between inlet cam and crankshaft.

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The internal combustion engine according to the invention thus comes without multi-part Cams or complex hydraulic valve trains. The controllability of the angular assignment between inlet cams and crankshaft, based on the position of the crankshaft; advantageously 180 °.

A simple design of the internal combustion engine in which the Intake cam is formed on a camshaft, which is driven by the crankshaft via an endless belt, stands out according to the invention in that an adjusting roller is provided in the direction of rotation in front of the crankshaft, via which the endless belt . running and adjustable to change the effective length of the part of the endless belt that pulls the camshaft is. The endless belt can be, for example, a toothed belt or a chain.

Advantageously, the adjusting roller can be adjusted together with a tensioning roller that is resiliently biased against it, via which the returning Part of the endless belt is running. This ensures that the spring, which biases the tensioning roller, when the The length of the adjusting roller does not change, so that the angular relationship between the inlet cam and the crankshaft is largely adjusted is possible precisely and quickly without the influence of inertial forces.

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A further embodiment of the internal combustion engine in which an outlet valve actuated by an outlet cam is provided in an outlet of the working chamber, inlet and outlet cams revolve around a common axis, is characterized in that the inlet cam has a hollow outer shaft

in

or one of these recorded to its coaxial inner shaft is rotatably connected, the exhaust cam is rotatably connected to the inner shaft and the outer shaft, wherein the The outer shaft has a slot in the circumferential direction in the region of the cam connected in a rotationally fixed manner to the inner shaft, and that the outer shaft is adjustable relative to the inner shaft. In this embodiment of the internal combustion engine, there are thus inlet cams and exhaust cams arranged on a common shaft consisting of two concentric parts, which is driven in rotation by the crankshaft. To adjust the angular position between the inlet cam and the crankshaft the two parts of the common shaft, the outer shaft and the inner shaft, are adjusted against each other. This adjustment can either be a relative rotation, whereby the cams are then rotated accordingly relative to one another, it can but also a relative axial displacement, the cams then being formed by corresponding ones in one of the shafts Inclined slots can be adjusted. The association between the crankshaft and the one with the exhaust valve or valves

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cooperating wave "stays the same all the time, while the Assignment between the crankshaft and the one with your or the inlet cam cooperating shaft is adjustable.

For the mutual adjustment of the two coaxial shafts known devices, such as a sliding sleeve, which cooperates with one shaft via an axial slot and with the other via an inclined slot, worms, Planetary gears, differential gears, etc. can be used.

In a preferred embodiment of the internal combustion engine the cam, which is non-rotatably connected to the outer shaft, is rigidly attached to the latter and the cam interacting with the inner shaft rotatably connected to it through its inner contour.

In a further preferred embodiment, both are cams recorded on the outer shaft with a sliding fit and with the associated shaft by means of a in a diametrical hole of the Shaft received pin rotatably connected.

It is advantageous in the last-mentioned embodiment the inner shaft is longitudinally displaceable with respect to the outer shaft and the diametrical hole of the inner shaft is part of a winding one diametrical slot. In this way, the cam or cams cooperating with the inner shaft can be displaced longitudinally the inner shaft can be rotated in relation to the outer shaft.

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The inlet valve of the internal combustion engine according to the invention is preferred a flat seat valve. Such flat seat valves generate strongly turbulent flows, which in terms of optimal Mixture preparation is cheap.

The inlet valve is advantageously with sharp peripheral edges formed, which contributes to the formation of turbulence. It is favorable if the oitzring of the inlet valve protrudes inwards, Has sharp-edged ribs, the cross-sectional area remaining between the stem of the valve and the seat ring being larger than the passage cross-section of the valve when the valve disc is fully lifted off the seat ring.

The invention is suitable for both self-igniting and for spark-ignited internal combustion engines and is for two- and four-stroke engines applicable. Furthermore, the invention is suitable both for those working with a carburetor and for those with injection working internal combustion engine It is most advantageous Can be used where a mixture of air and fuel is already sucked in through the inlet, i.e. when working with a carburettor Internal combustion engines and in internal combustion engines in which an injection nozzle is arranged in front of the inlet.

With the invention, an internal combustion engine is created in which the entire process for throttling the processing in partial load operation

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Teten amount of mixture required energy to swirl the Mixture, d. H. is used for mixture preparation.

The invention is illustrated below with the aid of schematic representations for example and explained with further details.

They represent:

1 shows a partial cross-section through an internal combustion engine,

2 shows a device for controlling an intake camshaft,

3 shows a diagram to illustrate various assignments between the position of the crankshaft and the opening of the inlet valve in different operating conditions the internal combustion engine,

4- a longitudinal section through a first embodiment of a double camshaft,

5 shows a cross section through the double camshaft according to Fig. 4 along the line V-V Fig. 4-,

6 shows a section through the double camshaft according to FIG. 4- along the line VI-VI

7 is a section through a modified embodiment of a double shaft cam assembly;

FIG. 8 shows a cross section through an intake cam along the line VIII-VIII in FIG. 7,

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9 shows a cross section through an exhaust cam along the line VIII-VIII in FIG. 7, 10 shows a plan view of the double camshaft according to FIG

Fig. 7, ν

11 is a plan view of a modified embodiment

form of a double camshaft, '

FIG. 12 shows a cross section through a flat seat valve and FIG. 13 shows a view from below of a cylinder head. Fig. 1 shows part of a cross section through an internal combustion engine having a plurality of piston-cylinder units, one of which "* is shown. In a cylinder 12, on the top, a cylinder head 14 set, a piston works 16 via a connecting rod> 18 a crankshaft 20 drives.

Above the piston 16, a working chamber is formed in the cylinder 12, into which an inlet channel 24 opens, which is in the cylinder head 14 is formed and to a suction pipe, not shown is connected or is itself part of the suction pipe. In the inlet 26 of the inlet channel 24 into the working chamber 22 is an inlet valve 28 with a valve disk 30, a valve stem 32 and a seat ring 34 is arranged. The valve stem is actuated by an intake cam 36 of a camshaft 38.

An exhaust valve and the one that works with it are not shown Exhaust cams as well as the entire mixture preparation

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device of the internal combustion engine, which is known per se e is executed.

The mode of operation of the internal combustion engine is such that in full load operation the inlet valve 28 opens near the start of a suction stroke, d. H. near the top dead center of the Piston 16. The inlet valve then remains open until the bottom dead center of the piston 16, as shown in FIG. 5 by the drawn out Curve I is shown, with the angle of rotation of the crankshaft on the abscissa and the lift of the intake valve on the ordinate is specified.

In the compression stroke of the piston following the suction stroke, the inlet valve and the outlet valve are the piston-cylinder unit closed. In the vicinity of the top dead center, the mixture sucked into the working chamber is replaced by a not shown Spark plug ignited, so that piston 16 is forced downwards on the following working stroke. During the subsequent Exhaust stroke opens the exhaust valve, not shown, and the burned mixture is out of the working chamber 22 pushed out.

If the engine is to deliver less power, the relationship between the stroke h of the inlet valve and the crankshaft is made

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or of the piston according to the dashed curve II in FIG. 3 and with the minimum output to be delivered according to the dash-dotted line Curve III of FIG. 3 is set.

In the assignment according to curve II, the inlet valve et ^T .: a opens at the point in time at which the piston 22 has maximum speed during its downward movement. The mixture is torn from the inlet channel 24 at high speed through the inlet cross section of the inlet valve 26 into the working chamber 22, whereby strong turbulence is caused in the inflowing mixture. The inlet valve remains open beyond the lower gate point of the piston, so that during the subsequent compression stroke part of the sucked in, highly turbulent mixture is pushed back into the inlet channel 24 and again while flowing through the inlet cross section of the

is set in turbulence in the open inlet valve. This / the inlet channel 24 expressed mixture is on the next intake stroke available as an already well prepared mixture.

Overall, the machine thus works in the partial load range with highly turbulent mixtures in the working chamber 22, as a result of which lean mixtures can be dangerous and, because of the rapid combustion, work can be carried out with a late ignition point.

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The machine can also be designed to achieve its maximum performance with an allocation of intake valve and crankshaft or piston allocation according to a curve between the curves I and II surrenders, d. H. even at maximum power, a part of the sucked-in mixture before it is compressed into the inlet port pushed back. This has the advantage that highly turbulent mixtures are used even at maximum performance, which means that these can be further emaciated. Such an internal combustion engine has a geometric compression ratio that is greater than the compression ratio that the sucked-in mixture actually experiences, as the volume of the Mixture is smaller than the volume of the working chamber 22 in the “bottom dead center of the piston 16”.

Fig. 2 shows a simple way of operating the internal combustion engine according to the various curves of Fig.

According to FIG. 2, a crankshaft 38 drives a camshaft 42 via a toothed belt 40, on which one or more inlet cams are attached. The internal combustion engine equipped with such a cam drive has for the intake cam or cams 44 and the exhaust cam or cams each have a camshaft, the camshaft provided for the exhaust cams not being shown is.

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The pulling part of the toothed belt 40 runs over an adjusting roller 46, the returning part of the toothed belt 40 runs over a tensioning roller 48. The adjusting roller 46 is mounted in a rod 50, in which, in turn, a rod 52 is telescopically movable, the is biased against the rod 50 by means of a spring 54. Of the Rod 50 is in a guide, for example on the engine block can be designed, according to the double arrow in the figure. Movable back and forth and for example \\ travel directly with a

the
Accelerator pedal of a vehicle, arranged in the / internal combustion engine

is connected.

The function of the described device is as follows:

In the position shown, there is the assignment according to curve II in Fig. 3 between the inlet valve and the crankshaft. If the rod 50 is now moved to the left, the shortened between the crankshaft 38 and the camshaft 42 v / effective length of the toothed belt 40, whereby the assignment between Inlet valve and crankshaft moves in the direction of curve III of FIG. 3, while when the rod 50 the assignment to the right in the direction of curve I in FIG. 1, that is to say in the direction of more power.

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Pig. 4 shows an embodiment in which to control Intake and exhaust valves of the internal combustion engine a double camshaft is used. This double camshaft has an outer hollow shaft 56 and a solid inner shaft 58, whose The outer diameter is equal to the inner diameter of the hollow shaft and which is rotatable with respect to the hollow shaft 56. The outer Hollow shaft 56 is formed in one piece with exhaust cams 60 (see. Fig. 5) while the inner hollow shaft 58 in cross section is not completely circular (compare Figures 5 and 6), so that with her inlet cam 62 over a corresponding inner contour are rotatably connected. The hollow shaft 56 has in the area each Inlet cam 62 has a recess 64 which makes it possible that the inlet cam 62 by corresponding rotation of the inner shaft 58 with respect to the hollow shaft 56 relative to the inlet cam 62 is twisted. According to FIG. 6, an adjustment range of the inlet cam 62 by approximately 80 ° is possible.

The installation of the double camshaft in an internal combustion engine is such that the hollow shaft 56 is connected to the crankshaft of the internal combustion engine is driven forth and that an additional device is provided by means of which the inner shaft 58 opposite the hollow shaft 56 is rotatable, the inner shaft 58 together rotates with the hollow shaft 56. The assembly of the twin cam shaft happens such that in the hollow shaft 56 first the

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Inlet cams 62 arranged in the recesses 64- ground and then the inner shaft 58 is inserted.

FIGS. 7 ″ to 10 show a multiple embodiment of a double camshaft. This also has an outer hollow shaft 68 and a solid inner shaft 70. Inlet cams 72 and outlet cams 7 ^ - with a sliding fit, ie without play, are received on the hollow shaft 68 portion of each intake cam 72 has the hollow outer shaft 68, a slot 76 in the circumferential direction, and has the solid inner shaft 70 has a through hole 78 with the slot 76 of the same width. in the through hole 78, a shaft extends to a _v stud bolt 80 passing through the through bore 78 8). The shaft of the stud screw 80 is received in the through hole 78 without play, so that the inlet cam 72 is fixed in its axial position by the slot 76 and is connected to the inner shaft 70 in a rotationally fixed manner is and is rotatable by rotating the inner shaft 70 relative to the outer shaft 68, as far as the slot 76 allows, in the Darge presented example at an angle of about 180 °.

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In the area of the outlet cam 7 ^ iron outer shaft 68 and inner shaft 70 through bores 82 or 84- through which the outlet cam by means of a stud screw 86, the shaft of which is free of play in the through hole 84 of the outer shaft 68 is received, is rotatably connected to the outer shaft 68.

The coupling of the outer shaft 68 to the inner shaft 70 can Step Example lsweise by means of a sliding sleeve 88 (see. Fig. 7) take place, which is placed on the inner shaft 70 and to the outer shaft 56 via a boss 90 and a formed in the outer shaft helical slot 92 and cooperates with the inner shaft 70 via a shoulder 94 and an axial slot 96 formed in the inner shaft. With an axial displacement of the sliding sleeve 88, which can be coupled, for example, to an accelerator pedal of the vehicle, the inner shaft 70 is rotated relative to the outer shaft 68, whereby the assignment of the inlet cams 72 to the position of the crankshaft changes when the outer shaft 68 is driven by the crankshaft will.

The assembly of the double camshaft according to FIGS. 7 to 10 takes place as follows:

First, the individual cams are pushed onto the outer shaft 68. Then the exhaust cams 7 ^ by means of the studs 86 rotatably connected to the outer shaft 68. (By-

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en
passage bore / 82 of the inner shaft 70 in the area of the exhaust cams

74- could be missing).

The inner shaft 70 is then pushed into the outer square 68 and the inlet cams are with appropriate alignment of the inner shaft to the outer shaft through the slots 76 and the through bores 78 rotatably therethrough with the inner shaft 70 connected. The inner shaft 70 is then in its correct Position rotated; then the sliding sleeve 88 is used, with which the coupling between the inner shaft 70 and the outer shaft he follows.

Fig. 11 shows a further embodiment of the double camshaft 10, in which the through hole 78 through replaces a helical slot 98 of the inner shaft 70 is. This achieves that the inlet cam, the rest of the is just as connected to the inner shaft 70, as shown in FIG. 8, in the event of a longitudinal displacement of the inner shaft 70 is rotated relative to the outer shaft 68. In the embodiment of the double camshaft according to FIG. 11, the inner shaft 70 can thus be coupled to the outer shaft 68 in a completely rotationally fixed manner and only needs to be axially adjusted to adjust the inlet cams be displaced with respect to the outer shaft 68.

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Fig. 12 shows an embodiment of an intake valve such as is particularly advantageous for the strong turbulence of the mixture flowing through its opening cross-section. This inlet valve 28 is a flat seat valve; H. the seat surface 102 of the seat ring 34 and the seat surface 104 of the valve disk 30 are perpendicular to the direction of movement of the valve stem 32 or to Direction of actuation of the valve. In addition, the free edges 106, 108, 110 and 112 of the valve are sharp, wherein the edge 112 on an inwardly projecting projection 114 of the seat ring $ 4 is formed. The protrusion 114 is preferred formed by individual, radially protruding ribs that taper to a point and that shown in FIG. 12 in longitudinal section have a triangular shape.

With the design of the valve according to FIG. 12, an optimal swirling of the flow through the inlet valve is achieved because this flow is strongly deflected and flows past numerous edges on which detachments form. By dimensioning of the valve in such a way that its opening cross section is smaller than the passage between the shaft 32 with the tips or the edge 112 ensures that the radially protruding ribs do not impair the full-load performance.

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13 shows a view from below of a cylinder head 116 with a combustion chamber cavity 117 in which an inlet 118 and an outlet 120 are formed. An inlet channel 122 ends in inlet 118 and an outlet channel 124 exits from outlet 120. The inlet channel is, for example, in that it is eccentrically brought up to the outlet in accordance with FIG. 3 or in other known ways Way, for example by means of inserts fitted in it, designed as a vertebral canal, so that the sucked in through it Mixture enters the combustion chamber in a whirling rotation.

Such a vortex duct is particularly advantageous in an internal combustion engine controlled according to the invention because it does , at the beginning of the opening of the inlet valve, the mixture sucked into a vortex movement rotating approximately around the axis of the inlet offset, but is ineffective when pushing part of the mixture back into the inlet channel, since the pushed back mixture does not come to so intense contact with the wall of the inlet channel that it also swirls - with opposite vertebral axis - comes.

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Claims (13)

AUDI NSU AUTO UNION 80? 0 Ingoistadt, 10/14/1977 Aktiengesellschaft IP 1491 Dr.Ba/L 11 Λ '/ ~ a Λ P.O. Box 220
8070 Ingolstadt Method for controlling the operation of an internal combustion engine, as well as internal combustion engine operating according to the method Patent claims: 1J method for controlling the operation of an internal combustion engine, »Especially for passenger cars, with at least one piston-cylinder unit, whose working chamber is connected to a suction pipe through an inlet in which an inlet valve is arranged is, whose opening time, based on the suction stroke of the piston, with decreasing, to be delivered by the internal combustion engine Power is shifted to late, characterized in that the closing time of the inlet valve with decreasing, from the internal combustion engine output to be delivered is also postponed to late, so that it is increasingly in the compression stroke following the suction stroke of the piston. 909818/0103 -2- 274738Λ 2. The method according to claim 1, characterized in that the opening time and the lift of the intake valve are independent of the service to be submitted. 3. Internal combustion engine, working according to the method according to claim 1, with at least one piston-cylinder unit whose Working chamber is connected to a suction pipe through an inlet in which an inlet valve is arranged, which of a rotatable inlet cam is actuated, which is driven by a crankshaft cooperating with the piston, characterized by a device (4-6, 48, 50, 52, 54; 56, 58; 68, 70, 88; 98) for adjusting the angular relationship between inlet cams (44; 62; 72) and crankshaft (38). the 4. Internal combustion engine according to claim 3 »in the / intake cam is formed on a camshaft which is driven by the crankshaft via an endless belt, characterized in that that an adjusting roller (46) is provided in front of the crankshaft (38) in the direction of rotation, via which the endless belt (toothed belt 40) runs and can be adjusted to change the effective length of the camshaft (42) pulling part of the endless belt. 8/0103 2747384 5. Internal combustion engine according to claim 4, characterized in that the adjusting roller (46) together with a resilient against it pretensioned tensioning roller (48) is adjustable, over which the returning part of the endless belt (toothed belt 40) runs. 6. Internal combustion engine according to claim 3 »" in which in an outlet the working chamber is provided with an exhaust valve actuated by an exhaust cam, with intake and exhaust cams revolve around a common axis, characterized in that the inlet cam (62; 72) has a hollow outer shaft (56; 68) or an inner shaft (58; 70) accommodated therein and coaxial with it is connected fixedly in terms of rotation, the exhaust cam (60; 74) non-rotatably with the inner shaft or the outer shaft is connected, the outer shaft having a slot (64; 76) in the area of the cam, which is non-rotatably connected to the inner shaft. has in the circumferential direction, and that the outer shaft is adjustable relative to the inner shaft. 7. Internal combustion engine according to claim 6, characterized in that the cam (outlet cam) connected to the outer shaft (56) in a rotationally fixed manner 60) is rigidly attached to this and the cam (inlet cam 62) interacting with the inner shaft (58) through its inner contour is non-rotatably connected to this. -4- 909818/0103 8. Internal combustion engine according to claim 6, characterized in that both cams (72, 74) on the outer shaft (68) with a sliding fit are received and with the associated shaft (68, 70) by means of a in a corresponding diametrical hole (78, 84-) the shaft received stud (80; 86) are rotatably connected. 9 internal combustion engine according to claim 8, characterized in that that the inner shaft (70) is longitudinally displaceable relative to the outer shaft (68) and that the diametrical hole of the inner shaft is part a tortuous diametrical slot (98). 10. Internal combustion engine according to one of claims 3 to 9i characterized in that the inlet valve (28) is a flat seat valve. 11. Internal combustion engine according to claim 10, characterized in that the inlet valve (28) with sharp peripheral edges (106, 108, 110, 112) is formed. 12. Internal combustion engine according to claim 10 or 11, characterized in that that the seat ring (34) of the inlet valve (28) inwards has protruding sharp-edged ribs (projection 114), -5-909818 / 0103 being between the stem (32) of the valve and the seat ring The remaining cross-sectional area is greater than the passage cross-section of the valve when it is fully lifted from the seat ring Valve disc (30). 13. Internal combustion engine according to one of claims 3 to 12 with an inlet channel ending in the inlet, characterized in that that the inlet channel (120) is designed as a vortex channel. 909818/0103