DE2514727A1 - Reciprocating IC vehicle engine - has adjustable variable profile cam for valves to vary compression ratio - Google Patents

Abstract

The engine has a reciprocating piston within a cylinder with inlet and exhaust valves operated by rocker arms and pushrods from a camshaft to control the admission and exhaust of working fluid. A cam mounted on a shaft causes a follower to reciprocate. The profile of the cam lobe varies in the axial direction ad the cam can be moved either manually or automatically along the shaft and also rotated round the shaft. The follower has a curved profile and the timing and extent of its movement depend on the position of the cam on the shaft. This varies the valve opening and consequently the volume induced into the cylinder which alters the effective compression ratio.

Description

25H727

Mitj a Victor Hinderks, London, England Internal combustion engine

The invention relates to an internal combustion engine with a chamber, a piston movable in the chamber, one in the Opening leading to the chamber, an outlet leading out of the chamber, to a system for supplying fluid medium the inlet and a system for removing fluid medium from the outlet.

It is desirable to use motors with variable opacity, cam / To have valve wheel and compression ratio. A number of advantages are achieved with this concept.

An engine with a controllable variable compression ratio allows the ratios to be changed when the engine is or is cold when the engine is started, which makes starting easier. The nature and extent of the change that is desired depends to a large extent on the type of motor used. For example, a pre-compressed or a turbo-compressed would Compression ignition engine an increase in starting pressures due to the ineffective lack of charge pressure Compensate charge. Another perhaps more important benefit of a variable compression ratio engine would be consist in the fact that the fuel is always burned at the optimum ratio for a given operating condition and

5098U / 0761

-2- 25U727

is saved through fuel. (Basically it can be said that the higher the compression ratio, the larger it is The work that can be achieved by burning a given amount of fuel, see Appendix A.) Engines are for such a compression ratio designed to function properly under the most favorable condition, usually at low rotation with high load. Indeed, this condition occurs for a small part of the entire business life on, and so could by changing the compression ratio upwards, more work can be extracted from the same amount of fuel during other work conditions. At acquaintances Constructions is there to change the engine compression ratios It is necessary to physically change the engine geometry, although this change is usually not easy and during the run of the motor cannot be reached at the moment.

The object of the invention is to create an internal combustion engine, in which the changes to the engine geometry described above are not required. The engine should be a variably effective one Compression ratio and / or a variable effective Have capacity. According to a further development of the invention, the motor should have working chamber valves with variable lift and opening times to have. Since engines today are built with such a capacity, at which the maximum required power is achieved becomes, introduces the possibility of lowering the effective capacity in a case where the maximum power is not required to save fuel and extend the life of the engine as a result of lower combustion loads is enlarged.

Most engines have fixed valve settings that compromise several ideal settings for different ones Modes of operation are. It can therefore be seen that the use of a variable camshaft under optimal valve settings would allow all conditions, thereby improving

509841/0761

Effectiveness per volume and consequently better fuel economy and / or compliance with baseline emission standards under various operating conditions will.

It is also an object of the invention to provide a device for improved To create charge composition regular in two-stroke engines »The effectiveness of two-stroke engines depends in considerable Measures depend on the proportion of air / fuel mixture and output gases in the cargo and also on how the relevant ones Components are mixed and dispersed during combustion. An improvement in charge composition control therefore leads to improvements in the mechanical efficiency and consequently to fuel economy. Through the improved mechanical and thermodynamic effectiveness of the engine designed according to the invention, the engine should have a wide Find application.

According to a further development of the invention, it should be possible with the engine to use different fuels.

The object of the invention is achieved by an internal combustion engine of the initially described type which according to the invention is characterized for selectively by an arrangement and which ationsrichtung controlled change in the operation of the inlet and the outlet, the assembly having at least one cam axially and in red is movable and has at least one cam projection with a progressively changing cross section.

The engine includes cam and cam follower means which cause the valve stroke and lift to selectively and can vary in a controlled manner, even when the engine is in operation. In the following description, under motor is any To understand the shape of a machine in which expansion cycles

50984 1/0761

25H727

applied, including pumps, and under valve is to understand any type of controllably enlargeable and shrinkable opening or passage, including of cone valves, ball valves, sleeves and butterfly valves, slots, gates, etc. The invention relates particularly on internal combustion engines of the internal combustion engine type including two-stroke and four-stroke, plunger-piston engines and rotor motors, diesel and gasoline motors, supercharged, turbo-charged and those with natural Induction, carburettor and fuel injected engines. The invention also relates to external internal combustion engines such as steam engines, Stirling and Rankine cycle engines.

With the invention, the effective compression ratio and / or the effective capacity through selective and controlled draining of part of the induction fluid that has already been sucked in or achieved by restricting or promoting the suction of the induction fluid, the arrangement according to the invention has at least one axially movable cam and in the direction of rotation, and the cam has one or more cam projections with a progressively changing cross-section. In the description are various embodiments of the Invention explained, in which a distinction is made between the variation of the compression ratio and the capacity and the provision of a valve mechanism for improved control and / or variation of the working fluid inlet and outlet the Chamber of Labor. This latter control and / or change made by a variable valve cycle and variable valve opening time is achieved provides an effective change in compression ratio and / or capacity. According to the invention the compression ratio and / or the capacity is changed by the means described below. An engine is like that designed so that its parts operate at a fixed geometry, thereby sucking in a predetermined amount of charge. This quantity

509 341/0761

-5- 25H727

corresponds to the cubic capacity. This displacement usually relates to the geometric configuration of the engine and is defined as the bore multiplied by the number of strokes, furthermore as capacity, but in this description it refers to refers to the amount of charge actually sucked in under a normal or desired standard or optimal working condition, further described as effective capacity

2 will. So has a motor with a bore cross-section of 50 cm and a stroke of 10 cm has a conventionally described displacement and a capacity of 500 cm, although it is actually in the In the case of a naturally aspirating engine, less charge volume measured at an external ambient density contains, for example 450 cm j and if it is a powered one Intake motor is about more load of, for example, 8OO cnr, These actual loads are referred to herein as displacement or effective capacity. If the engine described above is a Working volume in the top dead center of the compression stroke of 50 cnr, then the engine has a compression ratio of 10: 1. However, this relates to the geometric design of the engine, and it can be seen that the above two examples provide a real or effective compression ratio of 9: 1 or 16: 1.

According to the invention it is proposed to use this effective compression ratio optionally and controlled by releasing part of the sucked-in charge during the compression stroke to vary. It can be seen that at 50 cnr bleed in the case of the naturally aspirated engine mentioned above only 400 cnr of charge remain to carry out the work, reducing the effective compression ratio of 9: 1 to 8: 1 and a reduction in the effective capacity from 450 to 400 cm. It is suggested that this drainage by selective and controlled opening of a volume provided for this purpose, which is connected to the work volume takes place or in a preferred embodiment by

509841/076 1

-6- 25H727

the second opening one already provided in the engine Valve such as the inlet or outlet valve. A device that effects the second opening will be described later. Alternatively, the draining can be done by selective and controlled delayed closing of the inlet valve up to a certain value Duration of the compression cycle. If draining occurs by opening the inlet or outlet valve a second time, the timing is preferably chosen so that it coincides with the "pulse effect" j i.e. with the partial vacuum which behind the valve either by a returning pressure wave, which is caused by the charge being pushed back against the closed inlet valve arises, or arises at the moment of the initial charge.

A modified method of changing the effective compression ratio and the capacity of a motor consists in the selective and controlled acceleration of the closure of the intake valve or the reduction in the degree of opening of the intake valve, whereby the charge suction is reduced. This gives a choke effect, and in a majority of types of engines this method is less mechanically efficient than that facility described above.

The changes can be effected by automatic or manually adjustable devices and can depend on such factors as the engine speed, the load, the desire to prevent harmful exhaust gases, the ambient temperature, the atmospheric pressure, the quality of the available fuel, hot starting, cold starting, the desire to decrease engine power in certain circumstances without reducing engine speed proportionally or any other factor. The change can be made between operations of the engine or during the operation or be carried out continuously and endlessly between two desired polarities. In a majority of the cases, the engine will designed in such a way that with a polarity with increasing varia-

509841/0761

-7- 25H727

tion to a different polarity works. In other words, it works normally at the maximum compression ratio and Capacity with a decrease when certain running conditions make it desirable, as in the case of a motor vehicle with naturally aspirating engine. Or the motor can be designed so that it can only operate at maximum ratio / capacity works under certain conditions such as when starting and a reduction occurs under normal conditions, such as in the case of a powered marine engine. (See also Appendix A.)

Further features and usefulnesses of the invention emerge from the description of exemplary embodiments on the basis of FIG Characters. From the figures show:

Fig. 1A plan views of a main lifting profile and a and IB secondary lift profile of a cam for a variable compression ratio engine;

2A shows a cross section along the lines AA, BB, to 2D _c _ _{C DD}

3A shows corresponding perspective representations of the ^{to 3D} cam;

4a shows an arrangement for laterally sliding a camshaft depending on engine speed and load;

FIG. KB modified devices for driving the cam ^{bls 4Ρ shaft} of FIG. 4A;

Fig. 5A shows configurations of two-stroke combustion chambers; to 5B

6 shows parts of cams with a variable profile;

7-9 embodiments of roller cam followers; and 13A-13B

10 shows a cam with a profile that changes in the longitudinal direction;

509841/0761

Pig. 11, 12 embodiments of skid cam followers; and 14-16

17A configurations of variable cams and non-

^1S 'rotating cam followers;

Figure 18 shows cam / cam follower loads;

19 shows a cam follower lubricating device;

20 shows a cam follower with separate contact areas;

21A detailed cross-sectional boundaries between cam-

^{bls 21C} ram areas;

FIG. 22A is a top plan view of other configurations of FIG

^1S cam follower areas; and

_b j "g" 2 ^ e other cam follower configurations.

The device according to the invention has at least one cam which the cam follower in two directions, namely the direction of rotation and the axial direction, separately or in combination, can follow. The cam can be one, two or have a plurality of effective cam projections which can be separate or intermesh. The one with such a cam The cam follower used can either be round or curved and rotate freely about its axis, or it can, for example wisely be set by means of wedging to give a cross-section that is on a line parallel to the cam cross-section (either flat or curved in the other direction) consists of two or more different planes, these planes themselves can be curved, profiled or flat.

Figure IA shows, for example, a cam 1 on a slidable camshaft 3a is mounted, in which the primary lifting profile or the cam projection la with increasingly changing

50984 1/0761

25U727

Size shown from the side. It can be seen that the change in the longitudinal position of the cam relative to the fixed Guide roller results in the rotatable, domed head cam follower 2 being raised to various degrees will. The cam 1 has a much smaller secondary profile or cam projection 3 with a progressively increasing change, as shown in side view in Figure IB. Sections A to D in Figure 1A are in Figures 2A to 2D and illustrate the progressive change of the two profiles. Figure IB shows a modified cam follower 5, which cannot rotate freely and the three separate planes, a secondary cam lobe contact plane 6, a spacing plane and has a primary cam lobe contact plane 8. Such a cam follower is shown in greater detail in Figure shown. The cam and cam follower arrangement according to Figures 1 and 2 is suitable for mounting in a four-stroke internal combustion engine, to allow a second lifting so that the inlet valves release some of the charge that has been drawn in, the Ratio of section 2a high revs with maximum effective compression ratio and capacity and section 2b correspond to low revolutions with high load, which gives a minimal effective compression ratio and capacity, where the variation in ratio / capacity depends on whether and to what extent the second increase takes effect. As the cam moved in two dimensions, the main intake cam lobe has also been made variable to create an intake valve which has a cam projection with extreme proportionality to engine speed and load. The secondary lifting properties can be eliminated to an embodiment with a variable increase per cycle for the intake and / or exhaust valve of the engine. This embodiment is shown schematically in Figure 3B, which is a perspective view of a cam having only one cam projection, which varies in the elevation and / or dwell zone. Such a cam can also be used to control the optional late or early closing of a valve to drain or restrict

5098A1 / 0761

ken of the inlet of the charge of the engine working volume can be used. Figure 3D shows a similar cam, its cam projection but has a longitudinally twisted or axially inclined profile to produce a variable valve stroke. The feature shown in Figure 3D can be used in any embodiment of the invention can be used. Figure 3A is a perspective Representation of a cam that is used to actuate a special valve for discharging cargo from the working chamber of the engine suitable is. In this embodiment it has a cam projection, which is progressively reduced down to a part of the cam where there is no longer a cam protrusion or a rise is available. This feature can also be used in any embodiment of the invention. Figure 3C shows a cam with a plurality of cam projections which grow progressively parallel in contrast to the embodiment shown in FIG.

As an example, FIG. 4a shows an arrangement for lateral movement a camshaft as a function of the engine speeds and the load. The camshaft 3a is mounted in a device with a bearing 6 and a seal 7. One end of the camshaft 3a is connected to a pair of centrifugal weights 8 (which are shown here in simplified form) which Pull the camshaft to the right as the rotational speed increases because of the centrifugal force developed. The other The end of the camshaft is connected to a piston 9 which can be slid in a cylinder 10 which is closed on one side. Optional a compression spring 11 acts against the right-hand pull in the shaft caused by the centrifugal force and is balanced in the process by a compression spring 13 which is engaged with an adjusting screw 14 and a locking nut 15. An outlet 12 is connected to an intake manifold, wherein an increase in the engine load by a charge depression in the chamber 10 causes the Piston 9 and the camshaft attached to it are moved to the left. Are the cams shown in Figures 1 to 3 on the Attached to the camshaft shown in Figure 4A, then variations in the valve cycle and lifting, effective compression ratio

509841/0761

25U727

nis and capacity automatically by factors such as motor speed and / or load can be steered. For the sake of simplicity, the drive of the camshaft is not shown. That can about one splined and toothed ring 16 to chain 17 take place, as shown schematically in Figure 4B, or by Gears having teeth larger than normal as shown in Figure 4C. Alternatively, can the camshaft according to the plan view in Figure 4D and the side view 4E by an angled chain 17 via a sprocket 18, which is attached to the camshaft 3a, via an angled intermediate chain sprocket 19 of a Drive sprocket 20 are driven. In another embodiment shown in Figure 4F, the chain is not angled, but the links are designed and the chain is of such a length that lateral movement is possible. the The embodiment shown in Figure 4A has the example of the lateral Camshaft movement shown as a function of engine speed and load, but lateral movement can also be automatically controlled by any other parameter, for example by the engine temperature, exhaust gas rain Ib et revenge, etc.

In the above the basic principles of the invention have been described. In the further construction details, which are in particular refer to the cam follower, described with reference to various application examples and embodiments of the invention.

The second opening of the outlet or inlet valve or the opening another special valve during an engine cycle or in some embodiments the expansion cycle has many useful forms of application. In the case of a second opening of the exhaust valve, releasing a portion of the charge can be used to improve exhaust emission control, especially if thermal or catalytic factors are used in the output. This technique is preferred for engines used with direct ignition where the charge is to

509841/0761

Purge time does not need to contain fuel to deliver extra air or oxygen to the exhaust valve. In some embodiments may include draining a fuel Charge used to produce combustion and consequently separate heat in an outlet reactor, whereby the reactor has a suitably robust construction and the combustible charge and the remaining exhaust gases are suitable balanced and mixed to reduce the risk of detonation. In many applications, one will be used in accordance with the invention trained engine built so that some of the cargo is drained during certain conditions, such as low speed / high speed Load, being an increase in the 'combustion mixture occurs easily. If the discharge takes place via the exhaust valve, then air is simultaneously supplied to the exhaust system added to effect the reduction of partially burned ingredients in a rich mixture. In other embodiments or situations, the invention causes the charge to be discharged to the exhaust system for the purpose of removing the output emissions to regulate, whereby the engine effect is not directly influenced.

Another embodiment of the invention consists of one Arrangement for the Ablasserybder restriction of charge for an engine, to create a multi-fuel engine. It is known that such engines are desired which use various fuels can burn, especially in the military sector, in intercity vehicles or research vehicles. The engine is designed in such a way that that it can, for example, use diesel fuel at the highest compression ratio without draining, optional draining and regulated Draining fuel with higher viscosity burns. For example, an engine can be designed to run on diesel oil operates with an effective compression ratio of 16: 1, which by dumping charge to 10: 1 when in use of gasoline fuel is reduced.

609841/0761

25H727

In another embodiment of the invention, the method the partial discharge of the charge by a secondary opening of the outlet or inlet valve or through the opening another valve or by delaying the closing of the inlet valve to improve the charge composition to control. For example, it is known that in internal combustion engines, the charge from a combination of fresh fuel - / Air mixed and remaining exhaust gases from the previous one There is combustion. In the case of four-stroke engines, a suitable design of the valve stroke and the opening can reduce the remaining Reducing exhaust gases to such an amount that they do not significantly affect the engine, but it is not the case with two-stroke engines, where the load is always considerable Contains proportion of residual exhaust gases. There is almost always a controlled or desired fluid flow through the combustion chamber takes place, the proportion of exhaust gas that is present when the valves are closed, at a certain point, usually near the exhaust valve, be larger. This is particularly the case with engines in which the exhaust valve is in the upper part the combustion chamber, with the exhaust gases, which were previously more mixed with the charge, during the compression stroke due to their high temperature compared to the incoming cargo have risen and a layer near the exit valve form. According to the invention, the exhaust valve is opened a second time during the compression stroke, so that most of it the layer or pocket of the remaining exhaust gas, so as to improve the purity of the cargo at the moment of combustion. It can be seen that this diminishes the volumetric efficiency of the engine slightly, but it does compensates for the fact that the amount of freshly sucked in charge is increased, especially in the case of two-stroke engines where the Charge is almost always force-induced to some extent and adjustments are relatively easy. As an example, FIG. 5A shows a cross section through a two-stroke combustion chamber 21 shown with lower inlet ports 22 and a head outlet valve 23 with the piston 24 on hold

5098-1 / 0761

Paths up at the compression stroke are shown. The valve 23 has a specially domed head, which it the hot remaining Gases, which are indicated by the dots at 25, allow themselves to be at the highest point 26 above the chamber at To collect the circumference of the valve, which is opened for a short second moment during the compression stroke. Figure 5B shows a cross-section of a two-stroke combustion chamber 29 with a cross flow from the inlet ports 27 to the outlet ports 28, the piston 30 being at the bottom dead center. An additional outlet opening 31 is provided, which can be closed by a slidable gate 32 and is connected to an exit tunnel system 33. When a drain of residual exhaust gases (which collect above the main outlet opening) is desired during the compression stroke, then the gate 32 can be fully or partially opened during engine operation, or can be fully or partially opened during each Open and close clocks. The gate can be operated by a device, manually or automatically. The mechanics of his Efficiency is here for the convenience of the abbreviation Explanation of the corresponding principles omitted.

One embodiment and application of the invention is an engine for a motor vehicle, for example a passenger car, an overland tug, a railroad locomotive, a bulldozer or leveler, etc. Most vehicle engines are trained to operate properly in all conditions normally encountered using a given particular fuel. The fixed compression ratio a known engine is therefore determined by the need for adverse effects such as pre-ignition or knocking under the most severe operating condition that will be encountered, which is usually the low engine speed with high Burden is to eliminate. This situation occurs only for a small part of the engine operation over time or in small Were encountered and the engine could use the specific fuel during the other modes of operation at considerable

509841/0761

-is- 25U727

lent higher compression ratios to burn. It is known, that the power obtainable from the combustion of a certain amount of fuel is directly proportional to the increase the compression ratio increases within certain practical limits. It can therefore be seen that the invention by allowing the compression ratios to be changed in the way that these are always optimal for the given running conditions enables considerably greater performance can be obtained from a given amount of fuel compared to conventional engines. This creates a corresponding amount of fuel saved. For example, an engine of a passenger car that rotates 6,000 revolutions per Minute can run, be constructed with a geometric compression ratio of 13: 1 and be optional and controlled variable second intake valve lift during the compression stroke which means that a maximum of a quarter of the sucked-in charge can be drained off. The variation will be automatic controlled by a combination of engine speed and load. Under the worst situation of low RPM and high load (e.g. when starting under full load from a slope) the lowering would be greatest, creating an effective compression ratio of approximately 9: 1 (with a maximum effective compression ratio 12: 1 should be). In intermediate situations such as driving at low speed in the city, a partial deflation would be required take place, which results in an effective ratio of 10.5: 1, while nothing would be released when driving on the motorway gives an effective ratio of 12: 1, which would be referred to as 13: 1 in conventional measurement. As a result the overall effectiveness and the fuel saving, especially when driving on the motorway, is significantly greater than with a corresponding one conventional motor vehicle.

From the above descriptions it can be seen that a variation in the effective compression ratio is proportional and corresponding Result in variation in effective capacity. The variation in effective capacity can be an advantage in

509841/0761

. ₁₆ _ 25H727

prove a number of situations. For example, in the vehicle described above, the reduction in effective capacity, and hence fuel consumption, occurs during urban driving situations where fuel consumption is normally high. The reduction in the effective capacity does not necessarily have to mean a proportional reduction in the real (as opposed to the theoretical) engine output. If, for example, the effective compression ratio / capacity is to be reduced at low revs / high load, then a richer mixture can be properly burned under this condition, perhaps as a result of the higher BMEP % richer mixture, then roughly the same amount of fuel as a conventional engine can be burned, giving roughly the same performance. Specifically, however, part of the invention resides in the arrangement of the features described thereby forming a motor capable of substantial variation in effective capacity. It is known that motor vehicles are equipped with engines of sufficient capacity to provide adequate power in all situations, including emergencies, although this maximum power and capacity is seldom required and is seldom used. The possibility of the optionally reducible or variable effective capacity therefore achieves better utilization of the fuel and thus fuel savings. For example, if eh vehicle cm a motor having a maximum effective capacity of 2.000 cm, which is selectively and variably reducible to 1.400, then the lower portion of the effective capacitance and the proportional fuel consumption during the city driving and the constant highway driving is used, and the higher capacity are only used at high speed, when overtaking, driving under load, etc. The variation in capacity can be controlled manually or automatically by factors including the

509841/0761

Engine speed, load, ambient atmosphere, temperature and pressure, etc. So it has been described that according to the invention an engine with an optimal effective compression ratio and an engine with an optimal effective compression ratio Capacity can be created. In an ideal embodiment of the invention, this is used in a motor vehicle engine, and both advantages of the two sets of motor parameter variation are combined into a compromise.

The invention can be used in an engine to assist starting. For example, suitable compression ratios for the gasoline engines tend to increase with speed. Therefore, for a given engine, a lower compression ratio than would normally be possible during start-up and the correspondingly associated low revolutions may be required, which can be done manually or automatically by variation valve operation can be achieved in such a way that a maximum reduction in the effective ratio during starting is achieved. With other engines such as the turbo-compressed or pre-compressed engines, a higher Compression ratio than normally required, to compensate for the inactivity of an engine-dependent supercharger. In the latter case, the invention is specified in such a way that that it allows a discharge of charge during normal running, such as the secondary valve lift, and the secondary lift and the delivery does not occur during start-up. In a preferred embodiment, this principle can be used in combination can be used with a two-stroke engine that has a secondary stroke and output during normal running in order to achieve the remaining residual exhaust gases in the combustion chamber, remembering that many two-stroke engines have a type of assisted suction, which is engine dependent, and therefore difficulties arise at start-up. In another preferred Embodiment can be the above-described two-stroke engine a turbo-compressed or pre-compressed marine diesel engine or an engine for a railroad locomotive or a gen-

509841/0761

Ratorkrafted diesel engine or other large engines, which are normally between 100 to 1,000 revolutions per Minute run, be. Such engines are very common today in large merchant ships such as bulk freighters, super tankers, Container ships etc. used. It is known that the large individual engines that these ships can have are not can work properly below a certain number of revolutions, and this sometimes creates problems with fine maneuvering such big ships. In accordance with another aspect of the invention is an engine with optional and controlled charge ejection provided during the slow run, through which the power per revolution can be reduced and so less mechanical work is performed per specified engine speed. Naval ships were already applying for it specified of such a motor, in which the power per revolution is optionally variable, but this principle can also can be used with any other special or non-special engine. A preferred embodiment of the invention is a marine engine with a medium controlled charge discharge during the compression stroke, which is caused by an existing secondary valve lift or by an additional valve opening is effected, for example, to the charge composition to improve. During normal running, the engine has either less or no output during start-up and optionally has an output to reduce the power per revolution, the amount of the latter output possibly being is larger than during the normal run.

The principle according to the invention can also be used in an engine brake. One way to achieve the same is in the selective and controlled restriction of the intake port and / or a secondary opening of the intake valve so that the Most of the fluid medium sucked in during the intake stroke is expelled back into the intake system, with the Chamber is kept relatively low in fluid when all valves are closed and the piston at the top dead center

509841/0761

- 19 - 25U727

dream is. This causes the pistons against the relative partial vacuum work on the combustion cycle (inoperative for self-ignition engines). Alternatively, the exhaust valve can do so under engine braking conditions that there is almost no opening during the exhaust stroke or its main opening during the expansion stroke, either deriving the power from each ignition or in the case of diesel engines the gas is sucked back against the normal plus. Alternatively for this purpose, the cam according to the invention can be used, its a part has little or almost no profile, so that under engine braking conditions that part is opposite to the cam follower is, which results in almost no or no valve opening selectively of both the inlet valve and the outlet valve. If both or all of the valves are so held at rest during engine braking, then the combustion chamber becomes completed, eliminating a great deal of extra work from the piston to compress or expand the fluid medium therein must be applied, whereby a greater braking effect is achieved. All of these tricks, the cam alignments relative to the cam followers that are specifically chosen for the braking condition may include by mechanisms or engaged joints are released either automatically or by the operator. With great vices can the driver can progressively increase the braking effect by moving a lever that moves the camshaft along its axis of rotation shifts. This can initiate an upward movement (against the compression spring action) for the throttle pedal, which the Driver either by hooking his foot under the surface of the pedal and pulling it up, or by attaching it of an arc on the pedal as in a racing cyclist's pedals. In other words, a driver brakes by lifting his foot from the accelerator pedal, which goes back to its transverse position, and thus causes a certain engine braking. One heavier braking is effected by an upward accelerator lever action. Additionally or alternatively, the camshaft movement triggered heavier braking with the first

509841/0761

-20- 25U727

section of the brake pedal withdrawal movement and through light to medium brake pedal application as well as through heavier application will be triggered.

It has already been stated that variable cam mechanisms be ' are known, some of which have a cam that can perform a rotary and axial movement. Have such cams usually a conical cam projection of progressively increasing cross-section. Such cams usually have problems in the cam follower training. In theory, the cam follower should have a changing section along a parallel through the cam axis, as can be seen from the sections m and η through the cam of FIG. The invention indicates various embodiments, which are described below are described and which are designed so that the conventional problems associated with the cam followers of variable Cams are eliminated.

In order to establish the terminology and the assumptions made in this description, a typical variable profile cam 30 according to the invention is shown in FIG. 6, whose dashed part 31 shows the smallest profile and whose dashed part 32 shows the largest profile. The arrow 33 denotes the cam projection or working part of the cam, which is divided into three sections with the lifting part 3 ¹ J _5, the dwell part 35 and the lowering part 36. In some cam designs, the dwell portion is so small that it practically does not exist. The non-working part of the cam is indicated by arrow 37. The drawing shows an alternate cam follower 38 in contact with the non-operating portion of the cam and a cam follower 39 out of contact with the cam with an intermediate gap 40 between the two. In most rotary reciprocating mechanisms, some spacing and / or adjustment mechanism is provided somewhere so that the cam follower i only during the working part of the cam movement under heavy load.

509841 / 07S1

_ ₂₁ _ 25U727

the load. In the following description it is assumed that the cam followers are in light contact with the cam standing while working, but the material can have all kinds of cam follower configurations and positions relative to the Cam is applied while not working including the case where it stands against the cam under heavy load will. From Figure 6 it can be seen that each lateral line or plane of a cam follower is subordinate to different ones Angles must be inclined with respect to the direction of reciprocation. During the non-working part of the cam movement the plane of the cam follower should be approximately parallel to the cam axis, but during the working part the Plane be variably inclined to the cam axis, as shown by section η. The non-working part of the cam should be cylindrical in most embodiments, so that the Distance or the load between the cam and the cam follower during a cam sideways movement and the resulting variation of the profile remains constant.

In a preferred embodiment, the cam follower has a rotatably mounted rotatable guide roller. In Figure 7 a guide roller 40 is shown in perspective, which is mounted in bearings 41 which are attached to a frame 42, which by means of bearings 43 on a member 44 which can be moved to and fro is rotatably attached. The range of guide roller rotation is indicated by arrows 45. Optionally, a spring or tensioning or compression means 46 for biasing the guide roller to a position perpendicular to the member 44 during of the non-working part of the cam movement. For example, in Figure 8 there is a cam follower with a twin roller configuration which has a section taken parallel to the cam cross section, which is shown in FIG is where the centers of rotation 47 of the guide roller become a saddle which is rotatably attached to the reciprocable member 44 via a ball portion 49 and a ball 50

509841/0761

Although it is mostly comfortable, the movement of the two guide rollers referring to a reciprocating link, three or more rollers can be connected to one link, or groups of pulleys can be connected to various members 44, including one such case at which their back and forth movement is possible in succession, this latter embodiment not being shown. the Guide rollers are shown as cylindrical, but they can also be combinations of cylindrical and curved shapes for have a longitudinal curvature of the cam profile. Such guide rollers are shown as an example in FIGS. 13A to 13D shown.

In Figure IA, a cam follower is shown with a curved configuration, which in many ways is the simplest type of cam follower to be used with a variable profile cam can. Because of its apparently only point of contact (in theory all cam followers have an infinitely small one Contact point), this cam follower has a greater point load than other types. However, since he can usually turn, kick these high points load over a larger area of locations rn than with other types. Calculations show that such cam followers and cams have less wear than at is expected to be between about two to five times that of a conventional type of cam / follower assembly the same material is assumed. This less than initially assumed wear and tear suggests that it is economical to to form the subject matter of the invention so that curved cam followers are used, provided that this is a harder one Surface than with conventional cam arrangements. In another embodiment of the invention it is proposed that to modify the principle of the domed head to create a device that functions as a three-point or multi-point slide cam follower and has two or more separate contact areas that are used for cams with profiles or togarithmischen or irregular (rather than linear) increasing profiles

509841/0761

-23- 25M727

one such cam is shown as an exemplary embodiment in Figure 10, wherein 59 shows in elevation a main lifting cam projection and 51, in the plane, a secondary lift cam projection demonstrate. As an example, a multi-point cam follower with three separate contact areas is shown in plan view in FIG and shown in cross section in FIG. The cam follower is formed here from pressed sheet metal with three curved sections 53, which can come into contact with the cam 1, and has a rotating mechanism such as a rotating mechanism between the recesses Cap 58 for receiving a ball 57 of the reciprocating Link 44. In the embodiment shown, the inclines Slide to maintain its positions relative to the cam direction of rotation 56, since the Zuggewejung on the whole the contact point is twice as large as the pushing movement. However, it can optionally be rubbery or oppressive Elements 54 are provided, which the carriage in a desired Bring the position relative to the cam axis. A carriage was described, but each rotatably mounted element has two or more possible cam contact points can be used as a cam follower be used. Domed contact points have been shown, but any contact points can be Cross-section can be used that match a particular cam configuration used. An alternative point of contact is as an example in Figures 14 and 15 with reference to FIG the embodiment shown in Figures 11 and 12 is shown. As such, although the cam followers have been described in three or more points, two or more of them Points are combined to form a linear edge 55, as shown as an example in the plan view in Figure 16, the cross-section thereof Figure 12 corresponds. It can be seen that the provision of the cam followers of Figures 8, 9 and 11-13 is one more gradual, progressive but earlier reciprocal actuation than with a cam follower with a single point of contact is self-contained, but all adjustments to compensate for it can easily be made on cam profiles.

509841/0761

25H727

In Figure IB, a non-rotating cam follower was described, which has two or more defined surfaces, each of which corresponds to a particular situation of cam rotation, e.g. corresponds to the primary hub, secondary hub, non-work area, and so on. To ensure optimal effectiveness and wear and tear To ensure both the cam and the cam follower, it is usually necessary to remove the surfaces of the non-rotating Design cam followers precisely and in special shapes, mostly twisted, distorted flat or curved planes descriptive. For example, FIGS. 17A to 17D in cross-section / side view only different cam projections 60 and corresponding cam follower surface parts 6l where 62 is an intended rotating direction and 63 is the direction of reciprocation. The dashed area

64 corresponds to the possible cam follower contact areas for a given lateral position of the cam. It can be seen from the figures that the reciprocal cam follower axis is not must coincide with the cam axis of rotation but can be offset against this. (The embodiments in the figures 17A to 17D are not drawn exactly but only serve to illustrate the principle of the cam follower design used. ) Some of the cam followers shown have concave surfaces. In the various embodiments shown, this has as shown for example in Figure 18, advantages. With

65 is the axis of cam rotation in direction 68, with 66 being the axis of reciprocation of the concave cam follower 67 The impact of the cam lobe 69 causes a force to be exerted in approximately the direction 71 during the stroke at the approximate contact point 70 goes approximately in the direction 72, the loads 71 and 72 according to the vector principle can be combined to the load 73, which is directed approximately to the axis of reciprocation. The concave training increases the inclination so that the contact between the cam and the cam follower is in front of the line of the reciprocating axis, such pre-contact tends to put the cam follower rotary contact loads counteract on the cam follower.

509841/0761

-25- 25H727

Since the higher contact loads may occur between the cam follower and variable profile cams, the cam follower can have a bucket shape 72 with drainage channels 71 in the contact surfaces to allow lubricant in the bucket or sloping reciprocating portion to reach the contact surface, as shown in Figure 19 , where 73 is a lubricant. This embodiment can be used with any type of cam follower including the curved surface portion carriages. The cam followers should preferably be able to perform a certain rotational movement, as can be seen from the examples with ball and dome construction. If desired, a tensioning device 7 ^l \ can optionally be installed for restricting the rotary movement, which can be effective, for example, only in one plane. Non-rotatable cam followers are described with separate surfaces each corresponding to a separate cam function. For example, such a cam follower 81 is shown in elevation in Figure 20, 80 representing the axis of cam rotation, having a contact surface 82 having a twisted warped curved plane corresponding to the primary cam lobe, a contact surface 83 having a twisted warped flat plane corresponding to the secondary Cam projection 84 and a surface with a non-warped flat plane corresponding to the non-working area of the cam. Boundaries between the various separate areas can be of any shape including a sharp cross-section in Figure 21A, a rounded or stepped cross-section as in Figure 21B, or a cross-section with a negative indentation as in Figure 2IC, the boundaries being the area of any top view configuration describe. Figures 22A through 22C show examples of various end views of the cam followers of the cross section shown in Figure 20, with arrow 85 indicating the direction of cam lobe approach. The boundaries between the areas are shown clearly defined for simplicity, but can have any other configuration. Under certain circumstances, for example when the distances are sufficiently precise, the area corresponding to the non-working part of the cam can be eliminated altogether

5 Π 9 8 L 1/0 7 6 1

as shown in Figure 22D, for example.

For example, the non-rotating cam follower is circular Cross-section shown, but may have a cross-section of any other configuration, including a rectangular, oval, triangular shape or a shape corresponding to a television screen, etc. In a modified embodiment the non-rotating cam follower has no easily determinable limits, but has essentially one curved or rounded varying surface. As an example, such a cam follower is shown in plan view in FIG 23A and shown in various alternative cross-sections in Figures 23B to 23E.

All of the embodiments described above can be used in all possible ways Combinations with each other and with each type of engine can be used, in turn with each mechanism or with each Motor vehicle can be used. For example, engine starting can be improved by varying the introduction of charge ejection optionally by providing a secondary valve lift, but also by using the principles the delay or acceleration of the opening and / or the change in the opening of the inlet or outlet valves. To the By way of illustration of the principles, the cams and the cam followers have generally been shown as being fixed, but they can be made from any possible materials and have any possible construction and in particular be hollow, composite, on pressed Sheet metal, tube-shaped, etc., each matching an engine scale, for example from model airplanes or lawn mowers to large ones Internal combustion engines for overseas ships.

509841/0761

25U727

APPENDIX A.

In the case of certain internal combustion engines, notably air-sucked gasoline engines for motor vehicles, the risk of pre-ignition is a limiting factor in determining the compression ratio, and because of the time-dependent nature of the detonation, the risk of pre-ignition increases with increasing engine speed. In experiments carried out by Roensch and Hughes, among others, in 1950, it was found that for a given fuel (98 octane) an engine detonation-free at 800 revolutions per minute at a compression ratio of 8: 1 and at 4,000 revolutions per minute at a Compression ratio of 11.2: 1 could run. The power output advantage over an 8: 1 compression ratio at 4,000 rpm was approximately $ 11. When using a lower octane (88 octane) fuel, the compression ratio was 6: 1 at 800 revolutions per minute and 9.6: 1 at 4,000 revolutions per minute. Here the performance gains were 2OS ?. Today engines are generally revving higher than they used to be, while the octane numbers have been effectively reduced as a result of environmental protection laws. This suggests that the potential economic benefits of variable compression ratio engines are substantial. For example, assuming that such engines, if properly designed, save an average of ± 5% fuel, then the use of such engines on all motor vehicles in a country like the United States would allow oil imports for that country to be cut in half,

509841/0761

Claims (20)

25H727 Claims I!.,. Internal combustion engine with one chamber, one in the chamber movable piston, an opening leading into the chamber, an outlet leading out of the chamber, a system for supplying fluid medium to the inlet and a system for removing fluid medium from the outlet, characterized by an arrangement for selective and controlled alteration of the operation of the inlet and outlet, the assembly having at least one cam extending axially and in The direction of rotation is movable, and the at least one cam projection with a progressively changing cross section having. 2. Internal combustion engine according to claim 1, characterized in that the cam has a corresponding back and forth movable Link non-driving part and a laterally adjacent part for driving the movable back and forth Has limb to a controlled variable extent. 3. Internal combustion engine according to claim 1, characterized in that that the lateral movement of the cam is effected by a cooperative with the engine accelerator pedal or the cruise control Linkage is triggered. 4. Internal combustion engine according to claim 1, characterized in that the engine is irtiballiert in a motor vehicle and that the lateral movement of the cam is triggered by a linkage that interacts with the brake of the motor vehicle. 5. Internal combustion engine according to claim 1, characterized in that the cam has two or more profiles of at least one of which has a variable cross-section. 509841/0761 -29- 25H727 6. cams and associated cam followers, in particular for use with an engine according to one of the preceding claims, characterized in that the cam follower has at least one guide roller rotatable on one of mounted on the cam actuatable reciprocating member. 7. cams and associated cam followers, in particular for use with an engine according to any one of claims 1 to 5> characterized in that the cam follower has a member with at least two separate surfaces, which are normally are in contact with the cam, the element being rotatably mounted on a reciprocating member which can be actuated by the cam. 8. Cams and cam followers, in particular for use with an engine according to any one of claims 1 to 5, characterized in that said cam follower is essentially not around its Reciprocating axis is rotatable and has a surface which can come into contact with the cam and which is divided into two or more separate parts. 9 · Cam and associated cam follower according to Claim 7, characterized characterized in that at least part of the surface has a twisted warped plane. 10. Motor according to claim 1, characterized in that the lateral movement of the cam as a function of the engine operating speed is regulated automatically. 11. Motor according to claim 1, characterized in that Ue lateral movement of the cam as a function of the engine operating load is regulated automatically. 509841/0761 25U727 12. Motor according to one of the preceding claims, characterized in that it is an internal combustion engine and the arrangement for regulating the composition of the exhaust gases serves. 13. Motor according to one of claims 1 to 11, characterized in that that it is an internal combustion engine and the arrangement for improved combustion of various Fuels is used. 14. Motor according to claim 1, characterized in that the arrangement takes part of the fluid medium out of the chamber during of the compression stroke. 15. Motor according to claim 1, characterized in that the Arrangement brakes the engine. 16. Motor according to claim 1, characterized in that the Arrangement for varying the effective compression ratio of the engine is used. 17. Motor according to claim 1, characterized in that the arrangement for varying the effective capacity of the motor serves. 18. Engine according to claim 1, characterized in that the arrangement is used for improved starting of the engine. 19. Motor according to claim 1, characterized in that the The inlet and the outlet are formed from a valve and that the arrangement varies the duration of the valve opening. 20. Engine according to claim 1, characterized in that the inlet and outlet are formed from a valve and that the arrangement the amount of valve opening varies. 509841/0761