GB2304813A - Reducing environmentally unfriendly emissions from internal combustion engines - Google Patents

Abstract

Environmentally unfriendly emissions from internal combustion engines are reduced by introducing upper cylinder lubricant into the engine's fuel/air supply system, conveniently its fuel-supply line, and at a rate proportional to fuel-consumption, so that the lubricant is delivered direct to the combustion chamber. A flow-restriction device 8 including an exchangeable plug (13, Fig.2) having a bore, or an adjustable needle valve (14, Fig.3) is connected between a reservoir 7 of upper cylinder lubricant and the engine fuel-line 2. The reservoir 7 may be an air-tight, flexible and collapsable sachet (28, Fig.5) which when empty can be removed, discarded and replaced.

Description

"METHOD AND APPARATUS FOR REDUCING ENVIRONMENTALLY UNFRIENDLY EMISSIONS FROM INTERNAL COMBUSTION ENGINES" This invention concerns a method for reducing environmentally-unfriendly emissions from internal combustion engines, and apparatus for incorporation in or attachment to such engines for practising the method.

These days the protection of the envisonment has assumed major importance in many different fields of activity, and not least in relation to the automobile industry - where great importance is attached to the restriction of environmentally-unfriendly exhaust emissions from all kinds of engine (usually either diesel- or petrol-engines) so much so indeed that in many countries there are now legal limits to the permissible levels of such emissions. In the United Kingdom at the present time a Ministry of Transport MOT Test Certificate cannot be issued in respect of any vehicle unless the exhaust emissions from that vehicle as shown by test are below the legal limits.

It is not however always easy to meet emission-level requirements. There are cases known to the Applicant where a vehicle only two years old and with a recorded mileage of under 60,000 miles has failed to secure an MOT Certificate because the emission levels from its exhaust system proved too high to meet the legal criteria.

Moreover it is clear that in the years ahead the level of emissions permissible will be reduced.

There are of course various ways in which the industry has been striving to reduce emission levels. One approach has been to adopt the use of additives which promote lubrication of the walls of the explosion chamber within the engine cylinders, such additives being usually referred to upper cylinder lubricants. There are a variety of known upper cylinder lubricants upon the market, having various degrees of efficicacy, which are recommended for incorporation in the engine lubricating system.It will of course be appreciated that 4-stroke internal combustion engines, whether fueled by diesel or petrol (gasoline), already incorporate their own lubricating system, for circulating engine oil from the sump to and over the working parts; and that some part of that normal engine oil arrives in the piston, piston ring and cylinder assembly, where it provides the basic lubrication needed to enable the piston to reciprocate within the cylinder. However, while on each stroke of the piston some of the normal engine oil finds its way into that part of the upper cylinder swept by the piston it is there subjected to at least partial combustion during the explosion of the fuel/air mixture which drives the engine, and is thus continually burnt away.The intended function of the additives currently incorporated in the normal engine oil is to be more resistant than the normal lubricating oil to break-down during combustion, and indeed such additives are believed inter alia to possess the ability to form a physico-chemical bond with the surfaces of both the piston/piston ring assembly and the upper cylinder in the engine, thus creating a very thin but tightly-adherent film of the upper cylinder lubricant which modifies the metal surface and thereby reduces friction between the piston ring and the cylinder walls.

To the extent that the upper cylinder lubricant succeeds in its intended function, upon the one hand it reduces the clearance between the piston ring and the cylinder walls enough to significantly limit the escape of combustion gases between the piston and cylinder and/or upon the other hand it also facilitates the compression stroke of the piston within the cylinder. Either or both of these effects is generally beneficial from an environmental viewpoint, because both of them tend to increase the compression within the cylinder at the moment when the fuel/air mix is detonated by the spark plug, and the higher the compression at the moment of detonation generally-speaking the more complete will be the combustion, and complete combustion is the target at which one must aim in order to secure the lowest-possible emissions of environmentally-unfriendly material.

Thus, there are already available a variety of upper cylinder lubricants used in normal engine-lubricating oil, which within the limits of the Applicant's knowledge are all of them (though perhaps to varying degrees) able to promote the efficiency of the engine in achieving the completest-possible combustion of the fuel/air input, and thus promote lower emissions of environmentally-unfriendly materials from the exhaust system of the engine. Even so, the degree of improvement achievable by such upper cylinder lubricants when incorporated in normal enginelubricant oil are often not sufficient to keep such emissions within acceptable or legal limits, even with relatively new engines - and if they fail to achieve that objective today, they will fail by an even greater margin as the acceptable and/or legal emission limits are reduced.

The present invention is based initially upon the Applicant's realization that the limited effectiveness of upper cylinder lubricants can be attributed at least partly to their incorporation hitherto in the normal engine-lubricant oil, because on the one hand their effectiveness is then dissipated and wasted in engineareas which are not in need of them, yet on the other hand they are delivered by the engine oil in possiblyinadequate quantities where they are needed in the upper cylinder. The invention is further based upon a recognition, confirmed by test, that the efficiency of the engine, both generally and also specifically in relation to it ability to compress and combust the fuel/air mixture, can be significantly enhanced by delivering the upper cylinder lubricant precisely to where it is needed in the upper cylinder, by introducing it into the fuelsupply system for the engine.

According to the present invention there is provided a method for reducing emissions of environmentallyunfriendly materials in the exhaust from internal combustion engines, in which an upper cylinder lubricant is introduced into the fuel/air-supply system of an internal combustion engine and delivered thereby direct to the combustion chamber thereof.

Experience so far indicates that any upper cylinder lubricant able to serve its function when incorporated in normal engine-oil is able to fulfil the same function better when incorporated in the fuel/air-mix used to power that engine - and the exact nature of any particular upper cylinder lubricant that might be used is therefore not the direct concern of the present invention. It also appears that if for any particular purpose one known upper cylinder lubricant can be regarded as superior to another when supplied via the engine-lubricating oil, a generallysimilar superiority will be evident when it is supplied via the fuel/air system in accordance with the present invention.

It is possible to envisage atomizing or otherwise introducing the upper cylinder lubricant into the airinlet side of the fuel/air supply system, but it is currently believed preferable to effect introduction of the upper cylinder lubricant via the fuel-supply system.

Obviously the amount of upper cylinder lubricant delivered to the combustion chamber should be sufficient to be effective for its intended purpose, but not so great as to result in excessive and costly wastage. The amounts required in any particular instance will however be dependent on a range of factors, including for instance the nature of the fuel employed, the nature of the upper cylinder lubricant used, the type of engine (diesel or petrol), even the bore of the cylinder and the throw of the piston, and so on. The optimum proportions of upper cylinder lubricant to be employed must therefore be determined for any given case, perhaps with the aid of routine preliminary emission-testing procedures.

Once the optimum proportion of upper cylinder lubricant to fuel has been determined, it is of course desirable that the upper cylinder lubricant should be introduced into that fuel in approximately the correct proportions. The possibility exists of merely incorporating the upper cylinder lubricant in the fuel reservoir, but careful proportioning of the one to the other is then difficult and unreliable. It is therefore currently believed preferable for the upper cylinder lubricant to be added to the fuel in the fuel line.... and indeed as nearly as conveniently possible in an amount substantially proportionate to fuel consumption.This can be most simply and economically achieved by connecting a reservoir for the upper cylinder lubricant via a flowrestriction device to the upstream (suction) side of the engine fuel pump, thus permitting inflow of upper cylinder lubricant via the flow-restriction device from the reservoir under the influence of the suction in the fuel line which also draws fuel from the fuel tank. The proportion of upper cylinder lubricant added to the fuel will then be dependent on the relative cross-sectional flow-areas of respectively the flow-restriction device and the fuel line.

As already indicated the optimum proportions of upper cylinder lubricant to fuel depend on various factors, and these optima can be determined by anyone competent in this field, perhaps with the aid of simple testing. From the viewpoint of this invention what is crucial is that the relative proportions should be adjusted to suit the circumstances, and then maintained at or about that optimum proportion irrespective of the rate of fuel consumption. Since the cross-sectional flow-area of the fuel line is for practical purposes incapable of adjustment (after manufacture of the engine) this means that in reality adjustments must be effected by varying the cross-sectional flow-area of the flow-restriction device which admits upper cylinder lubricant from the reservoir to the fuel flow-line.

The simplest arrangement for adjusting the crosssectional flow-area of the flow-restriction device is to provide a small-diameter bore in an exchangeable plug interposed between the reservoir and the fuel-line - so that by exchanging a plug having one bore-diameter for another plug having a different bore-diameter the adjustment can be thus effected. It is however more convenient and therefore advantageous if the flowrestriction device comprises a tapered needle valve coacting with a correspondingly-shaped valve-seating, the valve and valve-seating being held apart by a separation which defines the cross-sectional flow-area through the valve, and movable longitudinally with respect one to the other to vary that separation against resilient springbias under control of a cam.Adjustment of the cam to preset the longitudinal separation of the valve from the valve-seat, which can be carried out readily by anyone competent to "tune" the engine, will then adjust the proportion of upper cylinder lubricant metered into the fuel-line relative to fuel-flow therein.

According to another aspect of the invention there is provided apparatus for use in the method of this invention, which comprises a flow-restriction device including means for attachment thereto of a connection to a reservoir of upper cylinder lubricant, and means on the side of said device remote from said reservoir for attaching the device to the fuel-line of an internal combustion engine.

The means for attaching the device to the fuel-line will preferably comprise an inlet port in the fuel line on the upstream (suction) side of the engine fuel-pump, and detachable, fluid-tight engagement means around the inlet port on the fuel line and the exit port on the device inter-engageable to make an air-tight inter-connection therebetween.

The flow-restricting device itself should be so constructed as to permit variation of the cross-sectional flow-area of the passageway therethrough for emitting upper cylinder lubricant from the reservoir into the fuelline.

The reservoir must be so constructed that so long as it contains upper cylinder lubricant the latter is supplied, preferably under gravity, to the flowrestriction device but when the reservoir becomes empty there is no possibility of air being admitted via the device to the fuel line. One such possibility involves construction of the reservoir as an inverted container having means for admitting air to replace upper cylinder lubricant as it is consumed, said container being however fitted with a float valve which seals liquid egress when the liquid in the reservoir is essentially exhausted.

Another possibility, which at present is thought generally preferable, is for the reservoir to be constructed as a collapsible, air-tight sachet, which when empty can be removed, discarded and replaced by a fresh sachet.

The apparatus of this invention when in operation will of course comprise all of the previously-indicated essential elements, thus in sequence the fuel pump of the engine, the upstream (suction) side of the fuel-line supplying the fuel pump from the fuel tank, an inlet port in said fuel-line detachably inter-engaged with the outlet port of a flow-restriction device, said device including means for either exchanging or otherwise varying the flowrestricting element therewithin, and detachably engaged with the inlet port of said flow-restricting device connecting means whereby a reservoir containing upper cylinder lubricant is connected thereto in a manner which precludes admission of air when the reservoir is empty.

And in a still further aspect of this invention there is provided an air-tight container having means for attachment to a flow-restriction device of the kind herein described, said container being substantially full of upper cylinder lubricant.

In order that the invention may be well understood some preferred embodiments thereof will now be described, in greater detail but only by way of illustration, with reference to the accompanying drawings in which: Figure 1 is a simplified flow-diagram which illustrates the method of this invention, applied to introduce upper cylinder lubricant into the fuel-supply line of an internal combustion engine; Figure 2 is a cross-sectional view in the vertical plane through a short length of fuel-supply line showing an inlet port thereto fitted with an exchangeable flowrestriction device through which upper cylinder lubricant may be drawn into the fuel; Figure 3 is a schematic, partly cross-sectional view through an alternative, adjustable flow-restriction device;; Figure 4 is a schematic, partly cross-sectional view of a rigid, refillable container serving as a reservoir for upper cylinder lubricant for use in the method and apparatus of this invention; and Figure 5 is a schematic, partly cross-sectional view of a collapsible, discardable and replaceable sachet serving as an alternative reservoir for upper cylinder lubricant.

Referring first to Figure 1, it will be seen that as in any normal internal combustion engine fuel from the fuel tank 1 is drawn in the direction of arrows 2 through the upstream section 3a of the fuel-line by fuel pump 4, and thereafter delivered through the downstream section 3b of the fuel-line to the usual carburettor or injectors of an internal combustion engine 5. In accordance with this invention between the fuel tank 1 and the fuel pump 4 in the upstream (suction) section 3a of the fuel-line there is provided an inlet port 6 through which a supply of upper cylinder lubricant from a reservoir 7 thereof is drawn by suction into the fuel-line 3a via a flowrestriction device 8 in the direction of arrows 9.

Figure 2 shows a short length of fuel-line 3 having an inlet 6 defined by an externally screw-threaded stub 10 detachably inter-engaged with an internally screw-threaded union nut 11 mounted on one end of a flexible pipe 12 connecting with the reservoir 7 (not shown in Figure 2).

Mounted between the stub 10 and the union nut 11 is a flow-restriction device 8 in the form of a plug 13 having an axial bore therethrough, the diameter of which bore determines the effective cross-sectional flow-area through which upper cylinder lubricant from the reservoir 7 (not shown) passes via the flexible pipe 12 and the bore in plug 13 to the inlet port 6, there to mingle with fuel flowing through fuel-line 3. The flow of the fuel is shown by arrows 2 and the flow of upper cylinder lubricant is shown by arrows 9. The proportion of upper cylinder lubricant mixed with the fuel is substantially determined by the cross-sectional flow-areas of respectively the bore in stop member 13 and the fuel-line 3, and that proportion may be varied by replacing stop member 13 with another stop member otherwise similarly shaped but having an axial bore therein of another diameter.

Figure 3 shows an alternative flow-restriction device in which the exchangeable plug 13 of Figure 2 is replaced by an adjustable one wherein a tapered needle valve 14 coacts with a correspondingly-shaped valve seating 15 and is adjustable longitudinally with respect thereto (so as to vary the annular separation between the tapered valve surfaces) by means of a circular cam-follower surface in needle valve 14 coacting with a rotationally-adjustable, slightly eccentric cam surface on bolt 16. By turning bolt 16 through 1800 the longitudinal-separation in the axial direction between needle valve 14 and valve seating 15 can be varied from a fully-shut to a fully-open position, and the effective cross-sectional flow-area for upper cylinder lubricant through the flow-restriction device can be adjusted at will.

Referring now to Figure 4, this broadly-speaking shows the reservoir generally indicated 7 which comprises a substantially rigid plastics container 17 for upper cylinder lubricant (not shown), in the inverted position in which it will be disposed when in normal use. The container 17 is provided with an externally-threaded neck 18 detachably inter-engaged with an internally-threaded union nut 19 mounted on the end of flexible pipe 20 through which upper cylinder lubricant flows in the direction of arrow 9 to the flow-restriction device 8 (not shown in Figure 4). At the other, topmost end of container 17 it is provided with a filler cap 21 detachably engageable with the rim of a filler hole 22 through which the upper cylinder lubricant within container 17 can be replenished when necessary.In order to prevent air from entering the fuel system when the upper cylinder lubricant within container 17 becomes exhausted, an inverted frusto-conical float valve 23 is provided within container 17, the frusto-conical surfaces of which float valve 23 coact with correspondingly-shaped portions 24 of the inner surface of container 17 adjacent its neck 18, to effect a seal between the container 17 and the flexible pipe 20 when the level of upper cylinder lubricant within the reservoir 7 nears exhaustion. In order the more surely to achieve an air-tight seal between the float member 23 and the corresponding inner surfaces 24 of the container 17, the float member 23 is mounted at the lower end of an upstanding, axial rod 25, telescopically received in a depending tubular housing 26 mounted centrally of cap 21.Within the housing 26, urging rod 25 downwardly, there is a compression spring 27.

A simpler and therefore less costly and sometimes preferable arrangement for reservoir 7 is shown in Figure 5, where (as in Figure 4) a flexible pipe 20 carries upper cylinder lubricant in the direction of arrow 9 to the flow-restriction device 8 (not shown in Figure 5) and the end of flexible pipe 20 is secured via cap 19 to neck 18 provided at the bottom of the reservoir 7. However in this embodiment the reservoir 7 takes the form of a sealed sachet 28, formed of impermeable, flexible plastics material e.g. polyvinylchloride (PVC), which collapses as upper cylinder lubricant is withdrawn therefrom, and when empty can be detached from union nut 19 and discarded.

The sachet 28 at its top end has an integrally-formed flap 29 having an aperture 30 therein, and in use the reservoir 7 may be mounted in the engine compartment by hooking aperture 30 onto a suitable support member therefor.

Thus it will be seen that the sachet 28 with neck 18, flap 29 and hole 30 constitutes a discardable and replaceable accessory. In order to facilitate the use of this accessory, after filling the sachet 28 with upper cylinder lubricant its neck 18 is sealed by means of a pierceable membrane (not shown) extending across the neckopening, and the extreme inner end of flexible tube 20 projects within cap 19 and is cut at an angle to the axis so as to define a point 31 sharp enough to pierce the membrane across the neck-opening as the cap 19 is screwed up onto neck 18.

It will thus be seen that the method of the invention as illustrated with reference to Figure 1 above provides an effective and convenient way of maximizing the compression of the fuel/air-mixture within the combustion chamber of an internal combustion engine, thereby promoting the completest-possible combustion of the fuel therein, and thus restricting emission of environmentallyunfriendly materials in the exhaust. It will also be seen that the method of the invention can be readily practised using the simple equipment-modifications herein disclosed.

Claims (23)

1. A method for reducing emissions of environmentallyunfriendly materials in the exhaust from internal combustion engines, in which an upper cylinder lubricant is introduced into the fuel/air-supply system of an internal combustion engine and delivered thereby direct to the combustion chamber thereof.

2. A method as claimed in claim 1, in which the upper cylinder lubricant is introduced via the engine fuelsupply system.

3. A method as claimed in claim 2, in which the upper cylinder lubricant is introduced into the fuel at a rate substantially proportional to the rate of fuel consumption.

4. A method as claimed in claim 3, in which both the upper cylinder lubricant and the fuel are drawn by suction into the fuel-input side of the engine fuel-pump.

5. A method as claimed in claim 4, in which the upper cylinder lubricant is drawn by suction from an air-tight reservoir thereof via a flow-restriction device.

6. A method as claimed in claim 5, in which the flowrestriction device is exchangeable and/or adjustable to vary the cross-sectional flow-area through which the upper cylinder lubricant is drawn by suction into the fuel supply line.

7. A method as claimed in claim 6, in which the flow restriction device is adjustable over a range of presettable values of cross-sectional flow-areas.

8. A method as claimed in any of the preceding claims, and substantially as herein described.

9. A method for reducing emissions of environmentallyunfriendly materials in the exhaust from internal combustion engines, substantially as herein described with reference to any of the accompanying drawings.

10. Apparatus for use in a method of reducing emissions of environmentally-unfriendly materials in the exhaust from internal combustion engines, said apparatus comprising a flow-restriction device including means for attachment thereto of a connection to a reservoir of upper cylinder lubricant, and means on the side of said device remote from said reservoir for attaching the device to the fuel-line of an internal combustion engine.

11. Apparatus as claimed in claim 10, in which the means for attaching the device to the fuel-line comprise an inlet port in the fuel-line on the upstream (suction) side of the engine fuel-pump, and detachable, fluid-tight engagement means round the inlet port on the fuel-line and the exit port on the device inter-engageable to make an air-tight inter-connection therebetween.

12. Apparatus as claimed in claim 10 or claim 11, in which the flow-restricting device is so constructed as to permit variation of the cross-sectional flow-area of the passageway therethrough for admitting upper cylinder lubricant from the reservoir into the fuel-line.

13. Apparatus as claimed in any of claims 10 to 12, in which the reservoir is so constructed that as long as it contains upper cylinder lubricant the latter is supplied to the flow-restriction device but when the reservoir becomes empty there is no possibility of air being admitted via the device to the fuel-line.

14. Apparatus as claimed in claim 13, in which the reservoir is so disposed and arranged that upper cylinder lubricant will be supplied to the flow-restriction device under gravity.

15. Apparatus as claimed in claim 13 or claim 14, in which the reservoir is, when operative, an inverted container having means for admitting air to replace upper cylinder lubricant as it is consumed, said container being fitted with a float valve which seals the container against air/liquid egress when the liquid in the reservoir is essentially exhausted.

16. Apparatus as claimed in claim 13 or claim 14, in which the reservoir is constructed as a collapsible, airtight sachet, which when empty can be removed, discarded and replaced by a fresh sachet.

17. Apparatus as claimed in any of claims 10 to 16, which comprises in sequence the fuel pump of the engine, the upstream (suction) side of the fuel-line supplying the fuel pump from the fuel tank, an inlet port in said fuelline detachably inter-engaged with the outlet port of a flow-restriction device, said device including means for either exchanging or otherwise varying the flowrestricting element therewithin, and detachably engaged with the inlet port of said flow-restricting device connecting means whereby a reservoir containing upper cylinder lubricant is connected thereto in a manner which precludes admission of air when the reservoir is empty.

18. Apparatus as claimed in any of claims 10 to 17, and substantially as herein described.

19. Apparatus for use in a method of reducing emissions of environmentally-unfriendly materials in the exhaust from internal combustion engines, substantially as herein described and shown with reference to any of the accompanying drawings.

20. An air-tight container having means for attachment to a flow-restriction device of the kind herein described, said container being substantially full of upper cylinder lubricant.

21. An air-tight container as claimed in claim 20, wherein said container is a flexible sachet collapsible under ambient pressure as the upper cylinder lubricant is consumed and discardable when empty.

22. An air-tight container as claimed in claim 20 or claim 21, and substantially as herein described.

23. An air-tight container as claimed in claim 20 or claim 21 and substantially as herein described and shown in the accompanying drawings.