GB2060058A

GB2060058A - Internal combustion engine

Info

Publication number: GB2060058A
Application number: GB8028970A
Authority: GB
Original assignee: Individual
Current assignee: Individual
Priority date: 1979-09-19
Filing date: 1980-09-08
Publication date: 1981-04-29
Also published as: DE2937849A1; FR2465877A1; JPS5652560A

Abstract

An internal combustion engine with a reciprocating or rotary piston, has the combustion chamber supplied with air via a pipe 25 to adjacent an inlet valve 8 and at least one supplementary, non-gaseous, fluent, combustible material which is introduced into the chamber by suction. The supplementary material may be a finely-ground solid, such as flour, milk powder or charcoal, and/or a liquid, such as an alcohol. The supplementary material can be introduced into the air intake passage (6) immediately adjacent to the inlet valve (8), or through one or more ports (91) in the cylinder wall (2) at about the mid-stroke level of the piston (18). Control valves (95, 96) may be used to meter the supplementary material (93, 94). Automatically operating control valves may be linked to a probe in the exhaust passage (7) to vary the quantity supplied in dependence on the exhaust gas composition. The supply may also be varied in response to the accelerator pedal (102). <IMAGE>

Description

SPECIFICATION Internal combustion engines This invention relates to internal combustion engines.

The invention is concerned with an internal combustion engine comprising at least one cylinder; a working piston movable in the cylinder; inlet and exhaust valves and a spark or fuel injection device arranged in the cylinder head; an intake passage communicating with an inlet port or inlet valve; an exhaust passage communicating with an exhaust port or exhaust valve; a carburettor in the intake passage if a spark device is provided; and a feed pipe leading into the intake passage, having its inner end issuing immediately adjacent to the inlet port or inlet valve and its valve seat at a position upstream from the valve seat in the flow direction which is as remote as possible from the spark or injection device, and through which air can be introduced drawn from the end of the feed pipe which is remote from the intake passage.

The invention is applicable both to an engine with reciprocating pistons and also to an engine with a rotary piston.

The introduction of air through such a feed pipe, possibly with valve control, has already been proposed in West German patent application P 28 31 694. In this proposed arrangement however, only one feed pipe is provided, and it is proposed selectively to feed in starter gas or an emulsion of drilling oil and water. According to the proposed arrangement the inner end of the feed pipe lies substantially parallel to the valve seat of the inlet valve. Such an arrangement is included in the closely similar arrangement of this feed pipe within the framework of the present invention.

The present invention includes in this connection, in making use of this known proposed arrangement, the feeding in of air through a valvecontrolled feed pipe.

By this arrangement one already achieves the advantage that this air is introduced at a position which does not directly influence the ignition properties of the mixture in the working chamber of the cylinder, so that a stratification occurs. This feeding is accomplished by the suction effect which arises in the working chamber. By this means the combustion is improved, so that the exhaust gas purity is increased. Furthermore, an improved utilisation efficiency of the fuel introduced is also achieved.

It is also already known to introduce an additional medium into the middle level of the working chamber of the cylinder through an aperture, the introduction of the medium being determined by the suction effect of the piston as it moves down towards its lower point of reversal. In this connection is has been proposed to feed in air or liquid for a stratification about the crown of the piston.

It is an object of the present invention to - provide an internal combustion engine of the type first described above which is improved in such a way that the fuel consumption is reduced, accompanied by quieter running of the engine, and additionally with a substantial reduction in the output of impurities in the exhaust gases due to favourable combustion within the working chamber.

This is achieved in accordance with the present invention by an internal combustion engine of the type first referred to above in which additive feed means are provided which comprise a supply of at least one supplementary, non-gaseous, combustible, fluent material which can be introduced into the cylinder chamber by suction.

This supplementary, fluent, non-gaseous material, which is thus a different material from the introduced air, exerts an influence on the ,combustion within the working chamber due to its combustibility, with the result that the uniformity of operation is improved and additional power is produced, so that the fuel consumption is reduced.

In connection with this it is pointed out that this supplementary material is not introduced in a mixture with the fuel such as gasoline, but separately from the fuel in order to produce a stratification effect.

In a preferred arrangement, finely-ground combustible solid materials are used as the further supplementary material. The term "finely-ground" is intended to mean a grain size which is as small as possible. The grain size should be such that this finely-ground combustible material is capable of flowing easily and in its total amount has a large surface area with the fine grains enabling dispersion.

According to a preferred embodiment, flour and/or charcoal may be used as finely-ground additional material. These particularly advantageous finely-ground materials can be introduced separately or as a mixture. Wood flour and grain-flour may be used for example as suitable flour materials. However, also included are other particulate substances, such as milk powder for example. The above list is not exhaustive.

In another preferred arrangement, the supplementary combustible material is a liquid.

For this purpose, in a preferred embodiment, one can use alcohol, such as methanol and spirit.

Also included within the scope of the invention is the possibility that these materials, i.e. granular materials and liquids, can be introduced mixed together.

In one advantageous embodiment of engine, a feed pipe for air and for the supplementary material is provided and mixer for the introduction of the supplementary material is connected to this feed pipe. This results in an engine of advantageous construction with an additional carburettor connected to the feed pipe, such that in this carburettor there is produced either a mixture of air and liquid or a mixture of air and finely-ground additional material. The introduction of the mixture adjacent to the valve seat of the inlet valve at a position as remote as possible from the injection or spark device has the advantage that the ignition is not directly affected, and that an improved power output is achieved over the full stroke.

According to another advantageous arrangement, at least one further feed pipe is provided in the intake passage in advance of the inlet valve, with this additional feed pipe having its mouth positioned immediately in front of the valve seat of the inlet valve. For this purpose this further feed pipe may be formed as a twin pipe, with one of the two pipes being the feed pipe for the introduction of air.

Also included within the scope of the invention Is an engine with three feed pipes formed as a triple pipe within the intake passage. By this means one achieves a multiple-fuel engine, i.e. at least a three-fuel or multiple-fuel engine, if one includes the supply of gasoline.

In embodiments of engine having a valvecontrolled aperture at the middle level of the cylinder, according to a further preferred arrangement, this valve-controlled aperture is connected to a supply reservoir for the supplementary material. This leads to a stratification above the crown of the piston.

Included within this is the provision of two valvecontrolled apertures arranged at approximately the middle level of the cylinder and connected to two independent supply reservoirs for suitable supplementary materials.

It will be appreciated that a supplementary material can be introduced both into the intake passage immediately in front of the valve seat of the inlet valve and in the middle region of the cylinder. In this way particularly favourable operating conditions can be achieved. Included for this purpose may be the provision of at least one valve-controlled feed pipe which is connected to an inflow port or ports between the valve seats and which on the other hand is connected to a reservoir or reservoirs. The feed pipes issuing into the intake or suction passage in front of the inlet valve do not need to be controlled by valve means.

Such valve control is necessary however if a feed pipe issues directly into the working chamber of the cylinder. In this case a valve formed as a nonreturn valve can be used. Nevertheless, also included is an arrangement, also for feed pipes which issue into the intake or suction passage, in which a valve is provided formed as a metering valve and is influenced in dependence upon the vacuum in the intake passage.

In one advantageous embodiment, a further feed port at the middle level of the cylinder is connected by way of a non-return valve and a feed pipe to a jet-type constriction into which issues a rising pipe from a container holding a supply of the supplementary fluent material. Preferably, a valve is provided in this rising pipe which is controllable in dependence upon the vacuum in the carburettor of the intake passage.

If the term "valve-controlled feed pipe" includes in particular a non-return valve positioned as close as possible to the place of issue into the working chamber, with the non-return valve opening as a result of suction action from the working chamber and closing when pressure is exerted, then, according to another preferred feature of the invention, an automatically controlled valve can be arranged in a feed pipe.

From this one can achieve an advantageous construction in an automatic system where the valve is controlled in dependence upon the exhaust gas composition as determined by an exhaust gas probe arranged in the exhaust passage. By this means the metering action can be determined.

Within the supply container for the supplementary material there may be a conveyor device which is adjustable in respect of its output by means of a parallel rod system which is itself adjustable by means of the throttle lever for the butterfly valve of the main carburettor.

Furthermore there is preferably included an arrangement in which a container with at least one chamber for a supply of supplementary combustible material is connected to a further feed pipe communicating with a feed opening controlled by a non-return valve and at the middle level of the cylinder wall, with metering valve means arranged in the at least one connecting line to the further feed pipe, with advantageously at least one vaive being influenced in dependence upon the vacuum just after a choke in the intake passage. Preferably, at least one metering valve is provided with its setting dependent upon the position of the driver's pedal and influenced by the vacuum in the carburettor in the intake passage.

According to a preferred feature, a metering valve in a feed pipe is connected to an exhaust gas probe in order to adjust the valve in dependence upon the exhaust gas composition.

Preferably, the supply container has a vent opening at the top, and a feed pipe is introduced into the container as a suction tube extending right down to the bottom. This results in a simple arrangement.

In one advantageous arrangement a conveyor device is provided in association with the supply container at the outer end of the feed pipe, with the conveyor device additionally constituting a metering element for the supply of the quantity of the supplementary material. This enables one to determine the supply of material, while throughout enabling one to have adjustability of the conveyor device in order to be able to introduce different quantities of supplementary material by the suction effect under different operating conditions. As one such conveyor device, for a granular material, one can use a conveyor device with a bucket belt whose buckets pick up metered quantities of granular material and take it to the outer end of the feed pipe. Screw conveyors are also to be included. A supply device for a liquid can be a pump which can be arranged to have a variable capacity in order to accomplish the metering auction.

If a conveyor device is provided, then, according to a further preferred feature, one can arrange that the throughput or the particular quantity of material conveyed by the conveyor device is controlled in dependence upon a signal from the exhaust gas probe. For example, with pumps or screw conveyors, the speed of rotation can be adjusted, while with belt conveyors or conveyor wheels the feed speed can be varied.

In the sense of achieving fuel economy, within the framework of the supply of the supplementary material, the jet for the introduction of the gasoline provided in the injection device or in the carburettor is preferably reduced in size to approximately half that of the conventional jet.

This automatically produces a reduction in the fuel consumption.

In the case of an internal combustion engine with a circulating piston formed as a rotary piston engine, two feed pipes may issue into the intake passage, one of which pipes is connected to a supply reservoir for the supplementary material.

With a central positioning of a spark device in the end wall of the working chamber, the, feed pipes to the outside of the intake passage are preferably positioned as close as possible to the side wall of the housing. The greatest possible spacing from the spark device is achieved if the spark device is arranged in the centre of the running surface, while the feed pipes issue at the side walls, in order to promote a stratification effect.

It is envisaged that the supplementary material, to which the present invention relates, should amount to approximately 50% of the normal amount of gasoline supplied to an internal combustion engine.

If spirit is to be used as a liquid additive, then in this connection a mixture comprising at least 5% by weight of spirit in water is considered to be a preferred composition.

For the present invention it is important that the added supplementary combustible material is not introduced as a mixture with the gasoline, since then the stratification effect would not be achieved.

In order that the invention may be fully understood, a number of embodiments of internal combustion engine in accordance with the present invention will now be described in detail by way sf example and with reference to the accompanying drawings.

In the drawings: Fig. 1 is a sectional view through a first selected embodiment of internal combustion engine in accordance with the invention, having a piston which is reciprocable within a cylinder; Fig. 2 is a sectional side view of a cylinder head of a second embodiment of engine in accordance with the invention; Fig. 3 is a schematic sectional side view of another embodiment of internal combustion engine in accordance with the invention; Fig. 4 is a sectional side view of a cylinder head of yet another internal combustion engine in accordance with -the invention; Fig. 5 is a partial view of a further internal combustion engine according to the invention; Fig. 6 is a more detailed view of part of the engine shown in Fig. 5; Fig. 7 is an illustration of the detail area shown in Fig. 6 but showing an alternative arrangement;; Fig. 8 is a sectional view of another embodiment of internal combustion engine in accordance with the invention; Fig. 9 is a partial view of a further internal combustion engine according to the invention; Fig. 10 is a partial view of yet another internal combustion engine in accordance with the invention Fig. 11 shows an embodiment of internal combustion engine in accordance with the invention having a rotary piston, the engine being shown schematically and partially in section; and, Fig. 1 a is a part view of Fig. 11, being a section taken along the line Xla--Xla of Fig. 11 and being a plan view on the intake passage.

In each of the Figures the same or corresponding elements are indicated by the respective same reference numbers.

Fig. 1 shows an internal combustion engine in the form of a diesel engine with a cylinder 2 arranged above a crankcase 1. At the top of the cylinder 2 is a cylinder head 3 in which there are valve seats 4 and 5 for an inlet valve and an exhaust valve respectively. Leading from these valve seats there extends an intake passage 6, also referred to as a suction passage, and an exhaust passage 7. Valve members 8 and 9 of an inlet valve and of an exhaust valve respectively co operate with and engage the valve seats 4 and 5.

The inlet and exhaust valves have valve stems 10 and 11 respectively which are driven by rocker arms 12 and 13 in known mannerfrom a cam shaft 14. This cam shaft 14 obtains its drive by way of a transmission 1 5 from a crankshaft 1 6 whose crank drives a piston 18 in the cylinder 2 by way of a connecting rod 17. Within the cylinder head 3 there is provided an arrangement 19 which is either a spark plug or, as in the present case, an injection device which is in communication by way of a pipe 20 with a pump 21 which is driven from the crankshaft 14. The pump 21 is supplied with gasoline or diesel fuel from a tank 23 by way of a pipe 22, and this fuel is introduced into the cylinder through the injection device 1 9.

It will be appreciated that with this embodiment an air filter 24 is provided at the outer end of the intake passage 6.

In the case of an Otto engine operating according to the Otto cycle, such as is yet to be described, a carburettor is provided at the intake 24 and a spark device would be provided instead of the injection device 1 9.

It is known to provide an externally open feed pipe 25 whose inner mouth 26 is positioned directly above the valve seat 4 at a position which is as far as possible from the injection device 19, and which lies in a plane parallel to the valve seat.

Within the framework of the present invention there is connected, for example to the feed pipe 25, a reservoir 56 for a further, supplementary, non-gaseous, combustible and fluent material which may be a powder or a liquid. in the latter case a carburation device would be required.

In the engine shown in Fig. 2 the same parts are shown by the same reference numbers as in Fig. 1, and a carburettor 27 is arranged in the intake passage 6 between the valve seat 4 of the inlet valve and the air filter 24. Instead of the injection device 1 9 of Fig. 1, a spark plug 37 is provided in the cylinder head 3 and, in the usual way, is triggered by a distributor in the electrical circuit and corresponding in the drive system to the pump 21 of Fig. 1. The feed pipe 25 which is connected by way of a pipe 28 to the air filter 24 in this embodiment is one element of a triple tube and is associated with two further feed pipes 29 and 30 each of which is connected by way of a connecting pipe 31, 32 with a reservoir container 33, 34 for the supply of a further, non-gaseous, combustible material.These reservoir containers 33, 34 have dustproof ventilating apertures 35, 36 so that by the suction effect in the working chamber of the cylinder a corresponding quantity of the supplementary material is sucked in.

Fig. 3 shows an internal combustion engine in which a further feed pipe 38 is associated with the feed pipe 25. This further feed pipe 38 can be arranged to foliow the line of one of the further feed pipes 29, 30 of Fig. 2 or, as shown in Fig. 3, can have its mouth issuing at 39 between the valve seats 4 and 5 for the inlet valve and exhaust valve respectively. This feed pipe 38 leads to a supply 42 of material arranged in a container 40 and having a conveyor means 41 which carries the further supplementary, combustible material from the reservoir supply 42 to the outer end 43 of the further feed pipe 38. In this embodiment an exhaust gas probe 44 is located in the exhaust passage 7, in order to monitor the exhaust gases and their compounds.The probe 44 is in communication with the conveyor means 41 by way of a function line 45 in order to drive this conveyor means in dependence upon the exhaust gas composition, i.e. in order to call for a greater or lesser extra quantity of the further, supplementary, fluent and combustible material.

Fig. 4 shows the cylinder head of a carburettor engine in which two inflow ports 39 and 46 are arranged between the valve seats 4 and 5 for the inlet and exhaust valves. These inflow ports 39 and 46 are respectively connected to containers 40 and 48 by way of further feed pipes 38 and 47 respectively. These containers 40, 48 hold supplies of a further, supplementary, combustible material which can be introduced into the cylinder chamber. It will be appreciated that one or both containers 40, 48 can be connected to metering or driving means in order to determine the amount of the supplementary material supplied. For example, an exhaust gas probe 44 can be in communication by means of a function line 45 with a conveyor means 49 in the one container 48, while the supply from the other container 40 is metered only by the suction action which is created.

Fig. 5 shows an illustration corresponding to Fig. 2, but here with only one further feed pipe 30 in addition to the feed pipe 25, so that this example illustrates the use of a twin tube 50. A feed pipe 32 extends from above down into a container 51 holding a supply 34 of a further, supplementary material. The mouth 52 of the feed pipe is arranged close to the base 53 of the container so that the remainder of the supply can be picked up to the maximum extent possible. It will be appreciated that the container base 53 can be inclined to slope downwards towards the mouth 52 of the feed pipe. In the upper wall of the container 51 there is provided a charging opening which is closed by a screw fitting 54 which nevertheless has a dustproof ventilation hole 36.

Such a feed arrangement is feasible for any supplementary additive material, although in the case of liquids one should choose a particular depth of container in relation to the level of the inner end 55 of the feed pipe so that one does not need to create excessively large suction forces for the transfer.

It will be understood, in relation to the described embodiments, that valves are arranged in the feed pipes, and especially in the feed pipes which issue directly into the working chamber of a cylinder, these valves being in the form of check valves or non-return valves 57, 58, 59, 60, 61. It is also to be understood that such valves may be metering valves. With reference to Fig. it is pointed out that the reference numeral 56 represents a mixer which has an air intake tube 56' extending outwardly therefrom, so that the mixer forms in the actual sense an additional carburettor.As is shown with reference to Fig. 5, it is to be understood that the arrangement includes a metering valve, for example as indicated at 60 in Fig. 5, which can be influenced by way of a function line 63 in dependence upon an exhaust gas probe 62 corresponding to the exhaust gas probe 44. In the case of the formation of the valve 60 as a non-return valve, the cross-sectional aperture is adjustable. Also included is the provision of a valve 64 arranged upstream from for example the valve 60, or even other valves, this valve 64 being in communication with an exhaust gas probe by means of a function line 63, 65 in order to release or completely to throttle the supply of the supplementary, additive, combustible material in dependence upon the condition of the exhaust gases.

In order to accomplish metering, there is provided, as shown in Figs. 6 and 7, a conveyor device associated with the container 51 for the supply 34. One such conveyor device has already been indicated in Fig. 3 at 41. Figs. 6 and 7 show for example that such a conveyor device 41 for the metering may be a conveyor belt 66 (Fig. 6) which has for example cup-shaped holes 67, or a pump 68 (Fig. 7). Drive motors 69, 70 for the belt 66 and pump 68 are adjustable by means of a function line 45 or 63 in accordance with an exhaust gas probe 44 or 62.

It should be understood that a conveyor worm may alternatively be used in a corresponding manner As shown in Fig. 8, a container 71 for a supply 72 of a supplementary additive material is connected by way of a feed pipe 73 through a non-return valve 74 with an opening or port 76 which issues into the working chamber of the cylinder 2, this port 76 being arranged at approximately mid-stroke of the piston, i.e. at about the middle level between the points of reversal of the piston 1 8.

It will be appreciated that by this means, as an alternative to using the feed pipe 25 formed as a twin pipe or alternatively using the method shown in Fig. 1, a second additional material can be supplied in this way as described.

Fig. 8 shows an example in which the pump 21 of Fig. 1, which is driven by a transmission from the crankshaft 16, is here formed as a distributor 77.

It is further pointed out in relation to this that in addition to the port 76 for a supplementary additive material, an additional supply port 77 at the same level, or at a level somewhat offset from this, may be provided in the cylinder 2 in order to introduce yet a further supplementary material.

For this it is pointed out that such an additional port 77 can be controlled by a valve device 78 which includes not only a non-return valve but also a metering valve which can be influenced by way of a function line 79 in dependence upon the vacuum in the suction tube 6.

In Fig. 9, the further supply port 77 in the cylinder 2 is shown with a non-return valve 78 immediately adjacent to the cylinder wall, and in the associated feed pipe 88 there is provided a jettype constriction 79. This additional feed pipe 88 is open to the ambient air. Into the jet-type constriction there issues a rising pipe 80 from a container 81 holding a supply of supplementary, fluent, combustible material which is entrained in dependence upon the suction effect. In this embodiment there is provided a valve 82 between the container 81 and the carburettor-type arrangement which is created by the constriction 79 and pipe 80. This valve 82 is controllable by way of a function line 83 in dependence upon the pressure in the carburettor 27.A conveyor device within the container 81, as described before for example, is made suitably adjustable as to its output by means of a rod 87 of a parallel rod linkage. The other rod 84 of the linkage is the throttle lever for the butterfly valve 85 of the main carburettor. The two rods 87, 84 are jointiy adjustable by way of the accelerator pedal 86.

Fig. 10 shows a further feed pipe 89 communicating with a feed port 91 controlled by a non-return valve 90, the port 91 being at the middle level of the cylinder wall of the cylinder 2.

This further feed pipe 89 is open to the ambient air, and indeed by way of an air filter 91. A container 92 has two chambers 93 and 94 and it includes within each chamber a supply for another, additive combustible material. Between the chambers 93 and 94 and the further feed pipe 89 are connecting pipes 97, 98 with valves 95, 96 which make it possible to provide a metered supply.

If either both valves or one valve corresponding to the foregoing description are or is connected to an exhaust gas probe for the purpose of achieving control, then the embodiment shown in Fig. 10 requires that the valve 96 is connected by way of a function line 99 to the suction pipe, i.e. so that it is influenced in dependence upon the vacuum just after the choke 100. This choke is controlled by the driving pedal 102 by way of a rod system 101.

The other valve 95 is connected to the driver's pedal 102 or to the rod system 101 by means of a function line 103, and the vacuum in the carburettor indicated as a whole at 105 exerts a quantitative influence by way of an additional function line 104.

For the control function it is pointed out that valve 96 is controlled in the sense of its increased opening if the vacuum through the function line 99 increases, while the other valve 95 is increasingly opened in dependence on an increasing depression of the pedal 102 in the sense of an acceleration, although for this latter valve opening a further control influence is superimposed on it by way of the function line 104.

Preferably, a particulate material is provided within the chamber 93 as the additional material, while in the chamber 94 a liquid is used as the additional material.

Fig. 11 is a schematic sectional view of an internal combustion engine with a rotary piston in the form of a rotary piston engine. The piston 106 of known construction moves within a housing 107 which is formed as an epitrochoid. The housing 107 has an intake passage 108 and an exhaust passage 109 formed through it. The intake passage 108 is connected to a carburettor (not shown) so that combustion mixture is sucked in. Approximately opposite these passages there is provided a spark device 110. The piston has a hollow ring gear 111 arranged within it and this meshes with and rotates on a pinion 112. This is known.

Within the intake passage 108 there is additionally provided the feed pipe 25 which is connected to the air filter of the carburettor. This feed pipe 25 is formed, in the region of the intake passage 108, as a twin tube with a further feed pipe 113 which leads from a container 114 which holds a supply of a further additional combustible material and which may be formed in the manner of the supply containers already described.

As a result of the known diametrically opposed arrangement of the intake passage 108 and the spark device 110, it is possible to arrange the charging with the additional material to take place at the intake passage, and thus at the maximum possible distance from the spark device 110 which is directed centrally towards the moving surface of the piston 106. As shown in Fig. 11 a the two feed pipes 25 and 113 are arranged at the sides of the intake passage 108 which lie next to the side walls of the engine which extend parallel to the plane of the drawing. In this way, with this construction of engine, as with a reciprocating piston engine, the maximum distance from the spark device is achieved in order to achieve stratified charging.

If, especially with respect to Figs. 1 to 10, different possibilities for controlling the supply of the further supplementary combustible material are used, it is to be understood that the controls described above may be replaced by other types of control, having regard to the different ways of introducing the material. For example, the valves 57, 59, 60 can be controlled in a manner such as has been described with reference to Figs. 8 and 10, with the introduction of the material into the cylinder head being effected by an arrangement as shown in Fig. 9.

Claims

1. An internal combustion engine comprising at least one cylinder; a working piston movable in the cylinder; inlet and exhaust valves and a spark device or fuel injection device arranged in the cylinder head; an intake passage communicating with an inlet port or inlet valve; an exhaust passage communicating with an exhaust port or exhaust valve; a carburettor in the intake passage if a spark device is provided; a feed pipe leading into the intake passage, having its inner end issuing immediately adjacent to the inlet port or inlet valve and its valve seat at a position upstream from the valve seat in the flow direction which is as remote as possible from the spark or injection device, and through which air can be introduced drawn from the end of the feed pipe which is remote from the intake passage; and additive feed means which comprise a supply of at least one supplementary, non-gaseous, fluent combustible material which is adapted to be introduced into the cylinder chamber by suction.

2. An internal combustion engine according to claim 1, in which the supplementary material comprises finely-ground combustible solid material.

3. An internal combustion engine according to claim 2, in which the finely-ground material comprises flour and/or charcoal.

4. An internal combustion engine according to claim 1, in which the supplementary material comprises liquid.

5. An internal combustion engine according to claim 4, in which the liquid comprises an alcohol, such as methanol or spirit.

6. An internal combustion engine according to any preceding claim, in which the feed pipe is for air and the supplementary material, and in which a mixer is provided connected to the feed pipe and for the introduction of said supplementary material.

7. An internal combustion engine according to claim 6, in which the mixer is formed as an additional carburettor connected to the feed pipe.

8. An internal combustion engine according to any of claims 1 to 5, which includes at least one further feed pipe in the intake passage in advance of the inlet valve, said at least one further feed pipe issuing immediately in front of the valve seat of the inlet valve.

9. An internal combustion engine according to claim 8, which comprises two feed pipes arranged in the intake passage as parallel twin tubes.

1 0. An internal combustion engine according to claim 8, which comprises three feed pipes formed as a triple tube.

11. An internal combustion engine according to any of claims 8 to 10, constructed as a three-fuel or multiple-fuel engine.

12. An internal combustion engine according to any preceding claim, which includes at least one valve-controlled port through the cylinder wall at approximately the mid-level of the cylinder, said at least one valve-controlled port being connected to at least one supply container for said supplementary material.

1 3. An internal combustion engine according to claim 12, which includes two such valvecontrolled ports through the cylinder wall at approximately the mid-level of the cylinder, said ports being connected to two supply containers for supplementary material.

14. An internal combustion engine according to claim 12 or 13, which includes valve means for said at least one port comprising a non-return valve.

1 5. An internal combustion engine acccrding to claim 1 2 or 13, which includes valve means for said at least one port comprising a valve formed as a metering valve which is influenced in dependence upon the vacuum in the intake passage.

1 6. An internal combustion engine according to claim 12, in which the feed port at approximately the mid-level of the cylinder is connected by way of a feed pipe fitted with a non-return valve to a jet-type constriction, and in which a riser pipe from a container for a supply of said supplementary material issues into said constriction.

1 7. An internal combustion engine according to claim 16, which includes a valve in said riser pipe which is controllable in dependence upon the vacuum in a carburettor in the intake passage.

18. An internal combustion engine according to claim 17, which includes conveyor means associated with said supply container and adjustable in respect of its output by means of a linkage which is movable jointly with a throttle lever for the butterfly valve of the carburettor in the intake passage.

1 9. An internal combustion engine according to claim 12 or 1 5, which includes a container with at least one chamber for a supply of said supplementary material, at least one connecting pipe connecting the container to a further feed pipe which communicates with a feed port at the mid-level of the cylinder wall and controlled by a non-return valve, and metering valve means arranged in said at least one connecting pipe to the further feed pipe.

20. An internal combustion engine according to claim 19, in which said metering valve means is controllable in dependence upon the vacuum just downstream from a throttle in the intake passage.

21. An internal combustion engine according to claim 19, in which said metering valve means is controlled in dependence upon the position of the driver's accelerator pedal and is influenced by the vacuum in a carburettor in the intake passage.

22. An internal combustion engine according to any of claims 1 to 1 6, which includes at least one valve-controlled feed pipe connected on the one hand to inflow ports located between the valve seats in the cylinder head and on the other hand to container means for a supply of said supplementary material.

23. An internal combustion engine according to any preceding claim, which includes supply container means for the supplementary material having ventilation port means at the top and with the feed pipe acting as a suction tube extending down substantially to the bottom of the container means.

24. An internal combustion engine according to any preceding claim, which includes a conveyor device arranged in association with a supply container for a supply of said supplementary material, the conveyor device guiding the supplementary material to the outer end of a feed pipe, and the conveyor device also constituting a metering means for the quantitative supply of said supplementary material.

25. An internal combustion engine according to any of claims 8 to 13, 1 6 or 19, which includes a metering valve in one such further feed pipe, and an exhaust gas probe connected to said metering valve to set the valve in dependence upon the composition of the exhaust gas.

26. An internal combustion engine according to any preceding claim, in which the jet provided in the fuel injection device or in the carburettor in the intake passage and for the introduction of the fuel has a cross-sectional area which is approximately half that of a conventional jet.

27. An internal combustion engine according to any preceding claim having a circulating piston and constructed as a rotary piston engine, comprising two feed pipes communicating with the intake passage, one of said feed pipes being connected to a supply container for said supplementary material, with a spark device arranged centrally in the end wall of the working chamber, and with the feed pipes arranged as close as possible to the side walls of the engine housing.

28. An internal combustion engine substantially as hereinbefore described with reference to any one of the Figures of the accompanying drawings.