GB2039601A

GB2039601A - Method and apparatus for introducing fuel into the combustion chamber of an internal combustion engine

Info

Publication number: GB2039601A
Application number: GB7943368A
Authority: GB
Original assignee: Individual
Current assignee: Individual
Priority date: 1978-12-16
Filing date: 1979-12-17
Publication date: 1980-08-13
Also published as: FR2444166A1; JPS55123320A; DE2854512A1

Abstract

Fuel is introduced into the combustion chamber of an internal combustion engine by a plunger reciprocated by a cam 14 via a two-port tappet 22, 37 having a liquid filled space 38 therebetween, the rate at which liquid escapes from the space 38 during the delivery stroke being determined by a valve 41 controlled by a device 11 as a function of an engine parameter, e.g. the speed of rotation of the combustion air in the engine's combustion chamber. Engine speed, exhaust gas emissions and/or the air density are other engine parameters mentioned. <IMAGE>

Description

SPECIFICATION Method and apparatus for introducing fuel into the combustion chamber of an internal combustion engine This invention relates to a method and apparatus to implement said method for introducing a fuel into the combustion chamber of an internal combustion engine, typically into the combustion chamber of an air-compressing, reciprocating internal combustion engine, for instance a Diesel engine etc.

It is prior art in internal combustion engines, typically in air-compressing, reciprocating internal combustion engines, such as Diesel engines etc., to effect the preparation of a mixture consisting of fuel and air, for instance, directly in the combustion chamber of such machines and to impart to the air as it enters the combustion chamber an intensive swirl about an axis of the combustion chamber as well as to inject the fuel to be introduced into the combustion chamber with a high pressure into the air swirl rotating in the combustion chamber. The rpm of the air rotating in the combustion chamber is selected high enough to permit the parts of air during injection of the fuel into the combustion chamber to contact the fuel and to mix adequately with it.

Reciprocating internal combustion engines especially with such a direct preparation of the combustible mixture of fuel and air in the cylinder and/or combustion chamber call for the generation of the air swirl and the fuel to be introduced into the combustion chamber to meet exacting requirements which involve correlating the swirl pattern of the air possible in a specific combustion chamber with a corresponding injection pattern or characteristics.

With a view to optimising internal combustion engines with respect to output, fuel consumption, exhaust emissions etc., such internal combustion engines are provided, for instance, with swirlinducing elements serving to generate the swirling motion of the air in the inlet region of the specific combustion chamber and devices are correlated with these internal combustion engines, generally, injection pumps with injectors connected downstream of these pumps in order to meet these exacting requirements with respect to swirl generation and injection of the fuel, i.e. the injection pattern.

A known air-compressing reciprocating internal combustion engine of this type is formed essentially by a combustion chamber arranged mostly in the crown of each piston with a swirl-generating inlet element each typically arranged in a cylinder head of the internal combustion engine and preceding the combustion chamber for the air to be delivered for combustion with a fuel, the jet of fuel injected being directed to the air swirl rotating in the combustion chamber in a manner that the said jet reaches the layers of the air swirl in the region of its pitch circles.

The injection of the fuel in this internal combustion engine is effected directly into the combustion chamber and swirl generation of the rotating layers is proportioned so that the differences of the rotary speed of these individual layers are matched to the variation of the diameter and/or shape of the combustion chambers. It is possible with this arrangement of the inlet element and the combustion chamber to ensure that the parts of the air are moved only once into the jet of fuel so that just as many parts of the fuel are combined with this air as are necessary for effective and optimum mixing and combustion of these air/fuel parts.In internal combustion engines, such as automotive Diesel engines, the situation may arise as a result of a higher speed such as is customary practice, for instance in private car engines with differences in speed between no-load and full load of 5,000 rpm and more that introduction of the fuel required cannot be sufficiently effected during the relatively short time available for this so that disturbances are liable to arise in the combustion process (cf. German Pattern Specification 1 576 014).

With a view to keeping disturbances of this type at a minimum, injection systems have been developed for the introduction of the fuel into the combustion chamber where the injection cycle in terms of period of injection and amount injected matches a predetermined injection pattern for the specific internal combustion engine.

Conventional injection systems used in internal combustion engines of this type will, however, meet with unsurmountable difficulties, where these systems are required to overcome large differences in the speed between no-load and full load. This is because it has been found that these injection systems tend to inject the fuel much too fast at low speed and much too slowly at high speeds. Added to this is the fact that substantial deviations from the desired injection pattern due to hydraulic and mechanical deformations and vibrations call for an improvement of the injection and control devices.

Such an injection system is essentially formed by an injection pump which, apart from a number of functional parts for the delivery of the fuel from a tank into the combustion chamber is formed with delivery means capable of being actuated by a cam mechanism. This delivery means essentially consists of a pump element arranged axially slidably in a casing in the form of a plungerwhich, at its end facing the actuating mechanism, is connected via a tappet to a driver. The tappet is made to project slightly from the driver and bears via an adjusting element against a further plunger-shaped tappet which is also axially slidable in a guide of the casing.

This further tappet is fork-shaped at its end facing the actuating mechanism of the pump element and there is a cam follower mounted on an axle supported in the cheeks of the fork and running onto and off a cam of the drive mechanism. The axial movement of the pump element initiated by the cam follower running onto the cam causes pressurization of an amount of fuel stored in the casing of the pump element, the amount of fuel as a result of the high pressure built up being delivered from this casing via a pipe to the injector.

The amount of fuel to be delivered from this casing to the injector is a function of the stroke of the plunger and the latter may be provided with a longitudinal groove or longitudinal hole which com municates with an annular groove or helical control edge. Return of the pump plunger after delivery of the fuel has been effected to the injector is provided by a return element, generally a spring, which is constrained between the driver of the plunger and the casing surrounding the cylinder of the plunger.

The cam, which is mounted on the shaft of the actuating mechanism, is in this case made very steep which produces a substantially spontaneous delivery of the fuel over a relatively very short period of time through the pump element and a pipe connecting it with an injector. In order to reduce the drawback of spontaneous delivery of the fuel, a most complex injector is required in this case which, apart from a number of control means, also has to have pressure-maintaining means without, however, being capable of meeting the requirements of the injection pattern of an internal combustion engine, especially one of the high-speed type (see German Pattern Specification 957,699).

The present invention has for its object to provide a possibility which permits not only the output, consumption and speed of the Diesel engine to be improved but, byaaccurate matching of the injection pattern, especially to the air swirl in the combustion chamber, to achieve combustion with a closely stoichiometric mixture of the air and fuel and where no free oxygen remains for nitric oxide compounds, i.e. NO emissions, to form while avoiding unneecessarily high air requirements.

According to the invention, this object is achieved in an internal combustion engine of the type initially referred to by a specific method whereby the period of time during which the amount of fuel to be injected into the combustion chamber is delivered, is capable of being matched to controlling parameters of the internal combustion engine, typically the rotary speed of the air for combustion rotating in the combustion chamber.

These means not only provide an advantageous solution to the problem underlying the invention, but an injection pattern is established for internal combustion engines which even where widely different combustion chamber shapes are used in internal combustion engines based on this concept can be readily transferred to these. Seeing that the rotary speed of the air for combustion rotating in the combustion chamber can be established on the strength of the specific values determined, such as the design of the swirl-inducing elements, the shape of the combustion chamber and the admission velocity of the air for combustion, the teaching of this method provides for the time of delivery of the fuel into the combustion chamber to be determined with due consideration to the rules for stoichiometric mixing.If this method is closely followed, then the mixing ratio is balanced and performance of the internal combustion engine can hardly fall outside a desired optimization limit, such as in respect of output, fuel consumption, exhaust emissions etc.

In the case of internal combustion engines where separate delivery means are provided for each cylinder and combustion chamber respectively, i.e. a separate delivery plunger, the rate of delivery of fuel into the combustion chamber at the end of the injection cycle providing injection of this fuel into the combustion chamber may, according to a further feature of the invention, correspond to the speed of the pumping motion of the delivery plunger at a maximum of 0.2 mm per degree cam angle.

As a further development of the concept of the invention, delivery of the fuel into the combustion chamber may be timed to occur in the upper region of the stroke of the delivery plunger.

These features and the associated matching of the injection pattern to the swirl formation of the air for combustion in the combustion chamber enables the pumping motion of the delivery plunger to be decreased by means of the specified rise of the cam, and especially the increase of the cam lift in the region of the positive stroke, so that less than 0.2 mm per degree cam angle or cam shaft rotation are achieved. As a result, the injection period is extended at low speeds of the internal combustion engine and, consequently, it is matched more closely to the desired constant injection cam angle for small and high speeds of the internal combustion engine.At high speed of the internal combustion engine, the smoother rise of the cam shape results in less pulsation and pressure disturbances occurring in the injection system and, thereby, a relatively shorter injection period being obtained. The desired injection pattern with a constant injection amount per degree cam angle in all speed ranges of the internal combustion engine can in this fashion be better realized in that the conventional abrupt increase of the cam rise is replaced by a smoother rise and consequently a pronounced curvature of the cam. As a result, it is possible to shift the injection period of the plunger stroke more towards the end of the cam lift because, in addition, thanks to the more circular or rather more arcuate and, consequently, softer shape of the cam, the nose of the cam is no longer subjected to such high stressing.

Apparatus serving to implement these features comprise at least delivery means, in this specific case a pump plunger, for each combustion chamber and provision to operate each delivery means by a control element of the apparatus as well as pipe means connecting the apparatus with an injector introducing the fuel into the combustion chamber with the pump plunger being formed with adjustable control elements to define the amount of fuel to be delivered into the combustion chamber and characterized according to the invention in that each delivery means is connerted to a drive supplying the pumping energy and in that the delivery means itself is operable by the said drive and in that said drive is connected to a governor controlling the magnitude of pumping energy the control functions of which are capable of being activated at least by controlling parameters of the internal combustion engine.

Apparatus of this type affords the advantage of compact construction combined with components which can be made in a relatively straightforward manner and which in addition warrant a high functional reliability.

With a view to adapting this apparatus further to the specified requirements, the pump plunger may in this apparatus be guided axially in a cylinder and supported via the restoring means (e.g. a spring) returning the pump plunger against a further axially slidable casing member, with this casing member being provided with a pressure body, typically in the form of a roller supported rotatably on an axle and with said pressure body or roller being adapted to run onto a cam arranged on the shaft of the drive, said apparatus being characterized according to the invention in that the cam is formed substantialy arcuately and in that the arcuate cam is designed so that during the positive stroke of the pump plunger one degree cam angle corresponds to a maximum of 0.2 mm stroke of the pump plunger.

Where this first feature is not quite sufficient, apparatus may be used where the delivery means, preferably also in the form of a pump plunger, is guided axially in a casing with said casing being supported via restoring means (e.g. a spring) returning the delivery means being supported against another casing member and which apparatus is characterized according to the invention in that this casing member is constructed typically of cup shape and surroundded coaxially by a further casing member typically of H shape in that these casing members are formed to telescope relative to each other and in that the one H shape casing member having the greater diameter forming a hydraulic space together with said cup-shaped casing member and in that said H-shaped casing member is connected via a passage provided in its shell to a hydraulic system filling and emptying said hydraulic space.

A further advantageous development of the invention is characterized additionally in that said Hshaped casing member is formed at its end facing the drive with a pressure body, typically in the shape of a roller supported rotatably on an axle which roller is capable of runing onto a cam arranged on the shaft of the drive and in that said cam is substantially of arcuate shape.

Another feature of this development of the invention consists in the fact that the arcuate shape of the cam is selected so that one degree cam angle corresponds to not more than 0.2 mm stroke of the pump plunger.

Apparatus employed for this purpose may be constructed as a straightforward configuration providing for an oil-filled telescopic tappet to be provided between the cam mounted on the shaft of the drive, i.e. the liftjing cam and the delivery means, e.g. a delivery plunger which tappet affords control of the actual and desired delivery rate in that amounts of oil are bled from the hydraulic space of the tappet at a decreasing rate as the speed of the internal combustion engine rises.

For further advantageous developments of the invention reference is made in particular to the remaining sub-claims.

A number of possible typical embodiments of the invention are shown schematically in the accompanying drawings in which: Figure lisa view of the apparatus with four delivery means arranged in a casing in the plane along the line ll-ll in Figure 2 with the delivery means being capable of being driven from a common shaft and connected via pipes with an injector each.

Figure2 is a plan view of the apparatus according to Figure 1.

Figure 3 is a section at the plane Ill-Ill in Figure 1 showing a mechanical delivery means in addition to a drive acting on it also mechanically.

Figure 4 is a section through delivery means similar to that in Figure 3, but in a hydraulic version and with a likewise mechanical drive acting on said delivery means and a considerably simplified version of the hydraulic system actuating said delivery means.

Figure 5 is a graph showing the injection pattern adapted to be used for the injection of fuel into the combustion chamber of an internal combustion engine.

Figure 6 is a section through delivery means similar to that in Figure 4, but shown in greater detail and the apparatus itself in cross-section.

Figure 7 is a graph showing the injection of the fuel into the combustion chamber with respect to the degree of filling of the combustion chamber with air and the speed of the internal combustion engine.

Figure 8 is a longitudinal central section through a cylinder and combustion chamber of an internal combustion engine in the section plane IX - IX in Figure 8 and Figure 9 is a plan view of the internal combustion engine shown in Figure 8 in the section plane VIll-VIll.

Figures 10 - 13 are further drive variants.

Apparatus 4 serving for the introduction of a fuel 1 into the combustion chamber 2 of a'n internal combustion engine 3 such as a Diesel engine etc., is essentially formed by an injection unit, e.g. in the form of an injection pump, which in a casing 5, comprises at least one delivery means 6 provided for each combustion chamber and at least one drive 7 actuating said delivery means in addition to supply means 8 and discharge means 9 for the fuel and control means 10,11 for the control of fuel delivery according to an injection pattern 12 tailored for the internal combustion engine.

In the typical embodiment of the apparatus 4 illustrated by Figures 1 to 3, there are four delivery means 6 arranged in a casing 5 of the injection unit and a common drive 7, the greater part of which is also accommodated in said casing, is provided for said delivery means. The drive 7 is formed by a shaft having separate cams 14 for each of the delivery means 6 with the cams having a substantially arcuate shape at its delivery side and designed as a so-called circular cam.The arcuate shape of the cam 14 is selected so that the cam provided on the shaft 13 is formed with a soft rise starting from a so-called zero point 15 on the surface of the shaft up to the full positive lift 16 of the cam and that the upper region of this ramp is formed so that in this region the stroke 17 of the delivery means 6 and specifically its delivery plunger 18 amounts to roughly a maximum of 0.2 mm per degree cam angle.In order to transmit the lift 17 of the cam 14 to the delivery plunger 18 the drive 7 in this particular typical embodiment of the invention is arranged so that a roller 19 provided on the deliverv means 4 and formina the Dressure member runs on the surface of the cam 14 and that this roller moves the delivery plunger 18 up and down according to the rise of the cam in the direction of the axis X of the delivery means. The shaft 13 of the drive 7 in this embodiment is driven in the conventional manner from an output element of the internal combustion engine 3.

The delivery means 6 itself is in this embodiment constructed in the fashion of a tappet which essen tiallyconsists of a delivery plunger 18 which is axially movable in a cylinder 20, a cup-shaped casing 22 moving said plunger and connected with it and disposed axially movably in a guide 21 of the device 4 as well as restoring means e.g. a spring 23 supporting said casing in turn against said cylinder and, in particular, serving to return the delivery plunger 18. Supported rotatably on the cup-shaped casing 22 via an axle 24 is a roller 19 which runs on the cam 14 of the drive 7.In order to permit the amount of fuel 1 to be introduced into the combustion chamber 2 to be defined and thereby to be metered, the end of the delivery means 6, i.e. the delivery plunger 18 facing away from the drive 7 which preferably is constructed so as to be movable even without any radial clearance in the cylinder 20, is provided with control means 10 in the form of a control port which may, for instance, be formed by a first axial groove or drilled hole 24 and a second, preferably helical or oblique groove 25 or drilled hole communicating with the former. In addition to these grooves 25 or drilled holes 24 there is an opening 26 provided in the cylinder 20 which communicates with the groove 25 or drilled hole 24 and which is connected via the supply line 8 to a delivery pump which is now shown in the drawing.

This delivery pump in turn is connected to a fuel tank from which the necessary amount of fuel is taken for the internal combustion engine 3.

This necessary amount of fuel is delivered via the line 8 and the delivery pump and, furthermore, through the opening 26 and the control means 10 into a collecting space 27 of the cylinder 20 from which this amount is forced by the rising delivery plunger 18 via the discharge line 9 into an injector 28 to 31 each preceding a combustion chamber 2. The amount of fuel 1 to be delivered per stroke of the delivery plunger 18 can be adjusted by varying the position of the control port, e.g. by turning the delivery plunger 18 about its axis "X".

As a result of this construction of each individual delivery means 6, it is possible according to the system underlying this invention to vary the injection pattern 12 for the introduction of the fuel 1 into the respective combustion chamber 2 which match es the graph defined in Figure 5. In this graph, the total possible lift of the cam 14 is plotted in mm rise against a vertical coordinate on the left-hand side.

The degrees of cam angle are plotted against the other horizontal coordinate. Against another also vertical coordinate is plotted the stroke in mm of the delivery plunger 18 per degree cam rotation H Ng The line starting at zero 15 of the coordinate system and, consequently, of the shaft 13 and typically of a sinsoidal shape, i.e. the lift 17 represents the motion curve of the delivery plunger 18; said motion curve resulting from the shapeothe cam 14 with its total lift and the rotary angle of said cam. Two marks 32, 33 are entered on this motion curve of which one mark 32 indicates the end of the pre-lift 34 of the cam 14 and the other mark 33 the end of the positive lift 16 of the same cam.Between these marks 32,33, there is the range of the positive lift 16 for delivering the fuel 1 into the combustion chamber which, according to the teaching of this invention means that the lifting speed of the delivery plunger 18 of the delivery means 6 in this section of the positive lift 16 should be no more than 0.2 mm per degree cam angle.The other curve plotted in this graph illustrates the injection pattern 12 and, consequently, the intensity and period of the delivery phase of the fuel, this curve also starting at zero 15 but rising more steeply than the motion curve and flattening out in the region between the end of the pre-lift (mark 32) and the end of the positive lift (mark 33) in order to change after a constant plateau 36 over a period of a few degrees cam angle into the descending motion, i.e. the return motion and, conseqently, the rapid termination of the injection cycle. the culmination point between the rising part of this curve and the constant, or substantially constant, part (injection pattern 12) may in the case of this setting lie at approximately 4.8 mm stroke and a cam angle H" Ng of approximately 0.15 deg.The culmination point for the end of the injection cycle in this case lies at the intersection of the plateau of the curve 36 with a vertical line constructed downwards from mark 33; this culmination point being preferably within the range of the positive lift 16, i.e. the end of injection is at approximately 10 after TDC (top dead centre).

In the graph shown here, the culmination points for the phase of decelerating delivery are clearly below the maximum value of 0.2 mm per degree cam angle. This meets the requirement according to the invention that the curvature of the flank of the cam 14 at the end of the positive lift 16 should be formed so that in this range of the positive lift, the 0.2 mm cam lift per degree cam angle can be covered at the most.

The construction of the delivery means 6 according to Figure 4 differs from the embodiment shown in Figure 3 essentially in that in this case the delivery means is constructed as a so-called hydraulic tappet.

This tappet is identical with the former tappet down to the cup-shaped casing 22 which entrains the delivery plunger 18. The difference is in the fact that the cup-shaped casing 22 is concentrically enclosed by another casing 37 which for simplicity's sake is shown in the shape of a capital H, these casings being capable of moving telescope fashion agajinst each other. The cup-shaped casing 22 serving as the driving element for the delivery plunger 18 together with the H-shaped casing 37 forms a hydrualic space 38 which via a passage 39 is connected to a hydraulic system 40. In the region of the passage 39, this hydraulic system 40 is provided with a valve 41 which is capable of being controlled by the control means 11 according to the selected injection pattern 12. Preferably the valve 41 is controlled as a function of speed by the control means 11, but it is conceiv able that the value is controlled as a function of smoke or any other behaviour of the internal combustion engine 3. Control of the valve 41 is adjusted so that, at high speed of the internal combustion engine 3, no fluid is emitted from the hydraulic space 38. In this case, the delivery plunger 18 moves at the full lifting velocity of the cam 14. As the engine speed decreases, valve 41 opens the return flow so that the fluid contained in the hydraulic space 38 is allowed to escape via the passage 39 and, possibly, by a ring chamber surrounding the opening and the repositioned valve 41 into a line 42 and, via this line, to a collecting tank 43.As a result of this position of the valve 41, the motion of the delivery plunger 18 slows down so that the rate of delivery of fuel 1 per degree cam angle decreases by the amount of loss of filling of the hydraulic space 38. The degree of filling of the hydraulic space 38 can be adjusted by re-positioning the control means 10, filling of said hydraulic space itself being provided by a pump 44 which draws liquid from the collecting tank 43. In order to be able to maintain the necessary pressure in the hydraulic space 38, there is a valve 45 which cooperates to ensure that the filling ofthe hydraulic space 38 is fully made up after each working cycle. in so far as leakages occur from the hydraulic space 38, these can be made up for via the valve 45.

In the detailed representation of the apparatus 4 according to Figure 6, the delivery means 6 has been physically modified but functionally it has remained the same, the parts differing from the schematic representation, e.g. the arrangement of the cylinder 20 which is preceded by a guide bush 46 and the hydraulic space 38 which has a spring 47 allied to it.

In order to prevent the H-shaped casing 37 from turning about the axis X, its surface is provided with a longitudinal slot 48 in which registers a pin 49 which is screwable into the casing 5. Generally, this embodiment of the invention has an adapter 50 connected downstream of the collecting space 27 through which the delivery means 6 is connected to the discharge line 9 leading to the injectors 28 to 31.

The cam 14 is again of arcuate shape with its rising ramp being steeper than the descending ramp.

The method according to the invention and the apparatus 4 conceived for it can be preferably used in an internal combustion engine 3 where the major portion ofthe combustion chamber 2 is located in the crown of the respective piston 51 and where the swirl-generating elements 53 are provided in the area of the inlet 54 for the air charge in the combustion chamber, said element 53 imparting to the air 52 the necessary swirl motion about an axis Z of the combustion chamber.

These swirl-generating elements 53 may be arranged in the port of the inlet 54 located in the cylinder head 55 of the internal combustion engine 3. These elements 53 are so constructed as to impart to the inflowing air 52 a rotation about an axis of rotation, typically the axes Z of the combustion chamber 2. For this purpose, the combustion chamber 2 is preferably of rotation-symmetric configuration and may be of cylindrical or spherical shape.

The air 52 introduced into this combustion chamber 2, i.e. the air swirl, during its rotation about the axis Z conforms to the shaDe of the combustion chamber with the individual air particles in the individual layers of the rotary swirl of the air 52 assuming due to the corresponding arrangement of the elements 53 and the control of the opening and closing times of the valve such a rotary speed that the air particles in all air layers have the same angular velocity. this control of the air 52 results in the air particles being rotated only once into a jet of fuel 1 injected into the combustion chamber.The fuel 1 is injected into the rotating air swirl so that it will contact the individual air layers tangentially as a result, firstly of the direction of the fuel jet and, secondly, the drift of the latter in the combustion chamber, with the point of contact being in the region of a pitch circle 55 of the individual air layer.

Proportioning the air swirl as a function of the speed of the internal combustion engine on the one hand and matching the injection pattern 12 to that speed, on the other hand, permit substantially optimized mixing of the air with the fuel particles so that the internal combustion engine 3 can be operated with good performance data in respect of fuel consumption, exhaust emissions, quiet running and other parameters.

The typical embodiment illustrated and described here, in particular of the delivery means 6 and the drive 7 of the same are mainly based on the use of mechanical/hydraulic parts. It is perfectly within the scope of the present invention to construct and operate these elements, for instance, electromechanically or electro-hydraulically or electrically only. Investigations have shown that, in particular electrical control means for the control of the injection pattern, are an advantage because these control means can be fed very simply with measured data of the internal combustion engine and because these characteristic data can be converted electrically into control signals.

In cases where the force, for instance, of electrical versions of the delivery means 6 fail to meet the requirements, it is possible to provide electrically controlled, but hydraulically powered actuating means, e.g. delivery plungers 18. Such electricalhydraulic control means offer an obvious advantage in that the straightforward electric control permits the necessary high pressures to be built up hydraulically so that the advantages of both systems can be combined in a most desirable manner.

According to a further embodiment of the invention, the drive 7 of the apparatus 4 can be connected via an offset-follower mechanism 56 to the output of the internal combustion engine 3 instead of connecting it directly to the output. The offset-follower mechanism 56 is formed essentially by a driving disc 57, a driving wheel 58 drivable from the output of the internal combustion engine and a driver wheel 59 as well as cams 60 positively connectable with said disc or wheel. The driving disc 57 is connected by means of a drag link mechanism with the link point A-B-C to an output disc 58 which in turn drives the injection pump, i.e. apparatus 4. At the centre link point B, there is a roller 61 which is guided along a cam contour of a stationary cam disc 62.In doing so, the roller 61 is imparted in addition to the rotary motion of the driving disc 57 which is performed at a constant angle of velocity, an oscillating motion from an inner point of reversal U to an outer point of reversal UA and vice versa. The distance of the two link points A-C provided on input and output discs 57,58 is increased and decreased alternately as a result which produces a non-uniform rotary motion of the output disc 58. The number of inner points of reversal U or outer points of reversal UA coincides with the number of injection lifts per rotation; the illustrations show by way of example a disc cam for a 4-cylinder engine with an ignition interval of 90 .

The injection desired according to the invention is achieved in that the injection angle a required for injection can be positioned as required from A' to A (FB minus FE) at a point of high or low angular velocity in that the disc cam 62 can be turned through a variable angle CLI Referring to Figure 11 the roller 61 is shown at its innermost point of reversal U1 with the distance A./.C increasing during its motion towards the inside and, as a result, the angular velocity of the output disc 58 is smaller than that of the input disc 57. Since the injection cam angle a corresponds to the greater angle a' of the rotation of the input disc 57 which is covered at constant rotary speed, the period of injection is increased accordingly.

In Figure 12, the cam disc 62 has been rotated by the angle 13 compared to Figure 11; the roller 61 is at its outer point of reversal UA with the distance A-C decreasing during its motion towards the outside and as a result the angular velocity of the output disc 58 is greater than that of the input disc 57. Here agajin the injection angle a corresponds to the now smaller angle a" and the period of injection is now correspondingly shortened.

In the typical embodiment illustrated in Figure 11 and 12, the correlation of the rotary angle a, a (ora,a") is selected so that the start of delivery FB for the delivery of the fuel always begins at the same position of the input disc 57; likewise, it is possible by matching the angle correlations as well as the curvature profiles, the lever lengths and angles and the roller diameter as a function of the rotary angle p to obtain an injection characteristic so that, for instant, the start of delivery FB is varied to an extent such as would be necessary in the case of control by an injection timer.A further possibility is derived from the fact that the rotary angle a of injection can be sub-divided into a decelerated part of an accelerated part of the rotary motion whereby, for instance, the injection pattern 12 can be influenced.

A further embodiment of the same principle is illustrated in Figure 13. Arranged in the input disc 57 is a sliding block 64 which is radially slidable in a radial guide 63 and, during the rotation, performs an additional oscillating motion along an adjustable cam curve 65 and entrains by means of a second guide 66 intersecting the guide 63 at an angle a moves a drive 67 which is firmly connected to the injection pump shaft 13 in a non-uniform manner, i.e. leading and lagging.

In order to match an adequate amount of fuel 1 to the degree of filling 0E of the combustion chamber 2 with air 52, the control means 10, 11 or 41 respectively are adjusted or controlled respectively so that a matchirig feature 67 is possible as a function of the degree of filling 0E and the speed in accordance with the load on the internal combustion engine 3. This matching feature 67 is variable and selectable and adjustable in respect of the degree of filling, i.e. the existing air charge and the selected speed.

Claims

1. A method for introducing fuel into the combustion chamber of an internal combustion engine, typically into a combustion chamber of an aircompressing, reciprocating internal combustion engine, such as a Diesel engine and others, characterized in that the time of delivery of the amount of fuel to be injected into the combustion chamber is adaptable to parameters of the internal combustion engine, typically to the speed of rotation of air for combustion rotating in the combustion chamber.

2. A method as in Claim 1 where said internal combustion engines are provided with separate delivery means (delivery plunger) for each cylinder and/or combustion chamber for the delivery of the fuel into said combustion chamber, characterized in that the rate of delivery of the fuel into the combustion chamber at the end of injection of said fuel into the combustion chamber corresponds to the speed of the pumping motion of the delivery means not exceeding 0.2 mm per degree cam angle.

3. A method as in Claim 1, characterized in that the delivery rate is capable of being decelerated and in that the extent of deceleration is capable of being controlled as a function of the engine speed as a controlling parameter of the internal combustion engine.

4. A method as in Claim 3, characterized in that the engine-speed-dependent control is a function of a signal acting on the delivery of the fuel.

5. A method as in Claim 2, characterized in that the delivery of the fuel into the combustion chamber is shifted into the upper section of the lifting path of the delivery means (delivery plunger).

6. A method as in Claim 1, characterized in that control of the time of delivery of the amount of fuel to be injected into the combustion chamber is effected according to a minimization of NO pollutant emissions (nitric oxide compounds) in the exhaust gas.

7. Apparatus to implement the method according to at least one of the Claims 1 to 6, with said apparatus being equipped with at least one delivery means for each combustion chamber and each delivery means being operable by the control element of said apparatus as well as each delivery means being connected via a line with one injector each injecting the fuel into the combustion chamber and with each delivery means being equipped with a pump element arranged in it and in which apparatus the pump element has adjustable control parts for defining the amount of fuel to be delivered into the combustion chamber, characterized in that each delivery means (6) is connected to a drive (7,66) providing the pumping energy and in that the delivery means itself is operable by this drive and said drive being connected with a controller in fluencing the injection pattern (12) the control functions of the controller being initiated by controlling parameters of the internal combustion engine (3).

8. Apparatus as in Claim 7 where each delivery means is guided axially in a casing and typically equipped with a delivery plunger each and where said casing bears via a restoring element (spring) returning the delivery means (delivery plunger) against another axially slidable casing part and where said casing is equipped with a pressure means, typically in the shape of a roller supported rotatably on an axle and where said pressure means (roller) is capable of running onto a cam arranged on the shaft of the flank of the cam (14) is substantially of arcuate shape and in that the arcuate shape of the flank of the cam is formed so that one degree cam angle amounts to no more than 0.2 mm stroke of the delivery means (6) or, respectively, the delivery plunger (18).

9. Apparatus as in Claim 7, where each delivery means is axially guided in a casing and each is typically equipped with a delivery plunger and where said casing bears via restoring means (spring) returning said delivery means (delivery plunger) against another casing part, characterized in that said casing (22) is typically of cup-shape and coaxially enclosed by another casing (37) typically of H-shape and in that these casings are capable of telescoping relative to each other and in that the one H-shaped casing (37) having the greater diameter together with the cup-shaped casing (22) forms a hydraulic space (38) and in that said H-shaped casing is conected via a passage (39) provided on its surface typically of slot-shape, to a hydraulic system (40) filling and emptying said hydraulic space.

10. Apparatus as in Claim 9, characterized in that said H-shaped casing (37) is formed at its end facing the drive (7) with pressure means (roller 19) running onto a cam (14) and in that the delivery range of the flank of the cam is of arcuate shape.

11. Apparatus as in Claim 10, characterized in that the arcuate shape of the flank of the cam (14) is cformed so that one degree cam angle amounts to not more than 0.2 mm stroke of the delivery means (6) which in this case is the delivery plunger (8).

12. Apparatus as in Claim 9, characterized in that the hydraulic system (40) is formed at least by a collecting tank (43), a pump (44) conected downstream of said tank and a controller (valve 41) connected downstream to said pump and a pump bypassing said controller and controlled by a valve (45) and a pressure-maintaining valve (45') and in that the hydraulic space is connectable alternately to a pipe (42) delivering to said hydraulic space and a pipe (42') returning to the collecting tank.

13. Apparatus as in Claim 12, characterized in that the controller (valve 41) is connected to control means (11) and in that the latter acts on said controller as a function of engine speed.

14. Apparatus as in Claims 7 and 12, characterized in that the setting of the control means (10, 11 and, respectively, the controller 41 and the control slot on the delivery plunger 18) are a function of a matching feature (67) adjusting the amount of fuel inisetoH tn thr InsH nn thn internal rnmhiictinn engine (3) versus speed (11) of the internal combustion engine and is effected through this.

15. Apparatus as in Claims 7 and 12, characterized in that the controlling parameters of the internal combustion engine are typically the speed, the exhaust gas emissions and/or the air density and in that the controller (valve 41) is controllable at least by one of these controlling parameters.

16. Apparatus to implementthe method especially according to Claim 1, where delivery means, typically in the form of delivery plungers, are provided for injecting the fuel into the combustion chamber and where said delivery means are connected to a drive providing the power input, characterized in that the drive (7) is preceded by a ratio gear (variable drive 56) changing its rotary motion during injection and in that said ratio gear is formed by an input disc and an output disc (57,58) a cam (64) maintained in guides (63, 66), and a lever system (hinge points A, B, C) guiding said cam.

17. Apparatus as in Claim 16, characterized in that oscillating levers (hinge points A, B) moving according to the contour of the cam (64) are provided for the ratio mechanism of the delivery motion and in that at their common fulcrum a roller (61) is pivoted which moves according to the contour of the cam and in that one end of said lever is hinged to the input disc (57) and the other end of the lever is hinged to the output disc (58).

18. Apparatus as in Claim 16, characterized in that a sliding block (drive 67) is provided for the ratio mechanism of the delivery system oscillating according to the contour of the cam (64) and in that the input disc and output disc (57, 58) are interconnected by two intersecting guides (63, 66) and the cam (64).

19. Apparatus as in Claim 16, characterized in that said cam disc (62) is adjustable as a function of engine speed and in that the theoretical injection period is capable of being extended at low speed of the internal combustion engine and abbreviated at high engine speed.

20. Apparatus as in Claim 16, characterized in that matching of the start of delivery with the curve contour of the cam disc (62) is effected so that when the cam disc is adjusted in accordanced with the engine speed a modification of the theoretical start of delivery for injection also occurs.

21. Apparatus as in Claim 16, characterized in that the distribution of the injection period on the curve contour is effected so that injection is partly decelerated and partly accelerated.