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Technical Field

This invention concerns the combustion of hydrocarbons. 5 More particularly it concerns the combustion of petrol (also known as gasoline) in an internal combustion engine or in other gaseous fuel burning appliances where petrol and oxygen-containing gas are supplied to the other appliance as an aerosol mixture. In an internal combustion 10 engine, such a supply of an air/fuel mixture occurs when a carburettor or fuel injector is used to control the supply of fuel to the engine.

Background to the Invention

In an ideal internal combustion engine, all of the fuel is 15 burnt to produce carbon dioxide, water and heat. In practice, it is not possible to produce such an ideal engine, primarily because the kinetics of combustion in an internal combustion engine do not permit a sensible amount of energy to be extracted from complete combustion of a 20 hydrocarbon fuel.

Pollution caused by the exhaust gases of internal combustion engines has been recognised for many years as a major environmental issue. The presence of the lead anti-knocking compounds in the petrol (gasoline) fuel used

25 for many years is a well-known source of toxic

_% lead-containing compounds in the atmosphere. Exhaust gases from motor vehicles not fitted with pollution control j_ equipment also contain what are now regarded as

unacceptably high concentrations of hydrocarbons, carbon monoxide and oxides of nitrogen.

To reduce this pollution, a number of countries have introduced legislation requiring emission-control equipment to be used with all new internal combustion engines. For example, in Australia legislation enacted several years ago has required all new motor vehicles to be powered by lead-free or unleaded petrol. In addition to the requirement for new engines to be powered by unleaded petrol, maximum emissions of hydrocarbons, carbon monoxide and oxides of nitrogen have also been specified in Australian motor vehicle design rules.

Currently in Australia, new cars using unleaded petrol as their fuel have to be fitted with catalytic converters to meet the emission control requirements. However, it is generally recognised that catalytic converters and other pollution-reducing devices detract from the power available from an internal combustion engine. In an effort to improve the power available from engines while keeping noxious emissions to a minimum, most engine manufacturers have adopted fuel injection systems to introduce fuel into the cylinders, instead of carburettors. With unleaded fuel, engines having fuel injected systems still require a catalytic converter to remove the by-products of incomplete combustion by burning them in the presence of a catalyst if they are to comply with the emission control requirements.

Catalytic converters are expensive items of equipment. If a significant improvement in fuel combustion could be

obtained within the engine, to provide essentially complete combustion of the fuel, the exhaust gases should meet the emission control requirements. In such a situation, the catalytic converter could be removed. That would result in a considerable saving in the cost of the engine and a more efficient engine would be produced.

Another aspect of engine performance which has received considerable attention over recent years is fuel economy. Most petrol engine manufacturers have improved the design of their engines to reduce the volume of fuel required to drive a motor vehicle while maintaining satisfactory performance as far as power and engine torque are concerned. A number of these engine developments use improved combustion of the petrol fuel to improve the fuel economy of the engine.

Disclosure of the Present Invention

It is a prime object of the present invention to provide an internal combustion engine in which the fuel is burnt more efficiently, to reduce the volume of hydrocarbons, carbon monoxide and oxides of nitrogen in the exhaust gas of the engine. It is expected that in some instances, use of the present invention will result in the engine meeting the emission control requirements of the Australian Motor Vehicle Design Rule No 37/00 without a catalytic converter being used in the exhaust system of the engine. It is also expected that, in most instances, use of the present invention will result in an improved fuel economy of the engine.

This objective is achieved in an internal combustion engine equipped with a carburettor by subjecting the air/fuel mixture leaving the carburettor to the influence of magnetic fields. In the case of an engine equipped with a central fuel injection system, the air/fuel mixture injected directly into the inlet manifold of the engine is subjected to the influence of magnetic fields. In each case, the air/fuel mixture is passed through a first magnetic field having its magnetic lines of force substantially at right angles to the direction of flow of the air/fuel mixture. Then, after a short period where no magnetic field is applied to it, the air/fuel mixture is passed through a second magnetic field which has its magnetic lines of force at right angles to the direction of flow of the air/fuel mixture and in the opposite direction to the lines of force of the first magnetic field. Preferably the strength of the magnetic fields is constant. However, each magnetic field may be cyclically varied in strength.

When the present invention was first conceived, the inventor was uncertain of the mechanism that caused the improved combustion. It was known that air/fuel mixtures are essentially a suspension of fuel droplets in the carrier gas (air), and the present inventor hypothesised that when the very small globules (droplets) of fuel in the air/fuel mixture are subjected to such opposed magnetic fields, the globules were stressed and the inter-molecular or intra-molecular bonds of the fuel are ruptured, to produce an aerosol which contains a large number of extremely small, possibly monomolecular, globules of the

hydrocarbon fuel, or of lighter fractions of the hydrocarbon fuel. Such an air/fuel mixture would enable the fuel (or its fractions) to burn substantially completely during the power stroke of the internal combustion engine.

Some scientists felt this hypothesis was unrealistic. However, it is now known that the effect of the present invention is to reduce, substantially, the droplet size of the air/fuel aerosol, thus permitting more efficient combustion of the fuel.

Thus, according to the present invention, a method of treating the air/fuel mixture (consisting of droplets of fuel in suspension in the air) being supplied to an internal combustion engine to reduce the size of the face droplets in the mixture comprises the steps of

(a) subjecting the air/fuel mixture to a first magnetic field which has its magnetic lines of force extending substantially transverse the direction of flow of the air/fuel mixture, and (b) subsequently subjecting the air/fuel mixture to a second magnetic field which has its magnetic lines of force substantially transverse the direction of flow of the air/fuel mixture and also substantially in the opposite direction to the lines of force of the first magnetic field, said pair of first and second magnetic fields being spaced apart from each other.

As indicated above, the strength of each magnetic field will normally be constant in value, but it may be cyclically varied.

In various implementations of the present invention, the magnetic fields have been established by two magnet assemblies each having a block or rod magnet with its magnetisation extending transverse the rod, between two elongate faces thereof. A pair of flat, soft-iron "pole pieces", each having a face with ^' dimensions greater than the aforementioned elongate faces of the block or rod magnet, are clamped by the magnetic force derived by the rod magnet to the elongate faces of the rod magnet to provide elongate pole pieces extending from the rod magnet at right angles to its direction of magnetisation. These two assemblies are used on opposite sides of the channel in which direction of flow of the air/fuel mixture flows, to establish the first and second magnetic fields of the present invention.

The distance between the elongate faces of the block or rod magnet of each magnet assembly, and hence the separation of the pole pieces providing the first and second magnetic fields, is normally between 5 mm and 10 mm, and is preferably about 6 mm when the present invention is used in a 4-cylinder internal combustion engine of a motor vehicle. The separation between the pole pieces of the opposed magnet assemblies can vary from 10 mm to about 30 mm, but is preferably in the range from 10 mm to 20 mm.

The two magnet assemblies are mounted within a body member which is used to define part of the channel through which the air/fuel mixture flows.

Thus the present invention also provides apparatus for applying a pair of magnetic fields to an air/fuel mixture being supplied to an internal combustion engine, said apparatus comprising:

(a) a body member having a channel extending therethrough, said body member being adapted to be mounted on the engine to form part of the flow path of the air/fuel mixture; and

(b) a pair of magnet assemblies mounted within said body member in diametrically opposed relationship to the channel extending therethrough, said magnet assemblies producing (i) a first magnetic field having its lines of force extending in a direction which is transverse the channel and orthogonal t,o the flow-through direction in said channel of said air/fuel mixture, and (ii) a second magnetic field having its lines of force extending in a direction which is transverse the channel and opposite to the direction of the lines of force of said first magnetic field.

Preferably the magnet assemblies are as indicated above.

The magnets used in the present invention must have a high Curie temperature (the temperature at which their remanent magnetisation reduces to zero), so that the magnetic fields established by the magnets are present at all the

temperatures likely to be experienced by an internal combustion engine mounted in a motor vehicle.

Embodiments of the present invention and examples of its effect, use and benefits will now be described, by way of illustration only, with reference to the accompanying drawings.

Brief Description of the Drawings

Figure 1 is a perspective sketch showing an embodiment of- the present invention connected between a carburettor air/fuel mixture outlet and the inlet manifold of an internal combustion engine.

Figure 2 is a vertical sectional view at 2-2 through the arrangement of Figure 1.

Figure 3 is a sectional view at 3-3 of Figure 2.

Figure 4 shows the individual components of one of the magnet assemblies used in the embodiment illustrated in Figures 1, 2 and 3.

Figure 5 illustrates two alternative constructions of the body members that have been used in implementations of the present invention.

Figure 6 is a partly schematic, partially sectional view of the application of the present invention to an engine having a carburettor with primary and secondary air/fuel mixture outlets.

Figure 7 is a sectional view at 7-7 of Figure 6.

Figure 8 is a partly schematic sectional view of an alternative embodiment of the present invention for use with a carburettor having primary and secondary air/fuel mixture outlets.

Figure 9 illustrates the equipment used in a university evaluation of the physical effect of the present invention on the droplet size distribution of an air/fuel mixture.

Figure 10 is a graph showing the measured droplet size of an air/fuel mixture, obtained using the equipment shown in Figure 9.

Detailed Description of the Illustrated Embodiments

The arrangement illustrated schematically in Figure 1 shows an embodiment of the present invention mounted between the air/fuel mixture outlet 10 of a carburettor and the inlet manifold 11 of an internal combustion engine. As shown in Figure 2, the carburettor has a butterfly valve 13, which is adjacent to the air/fuel mixture outlet and which, when opened fully, moves partly into the region below the outlet.

As shown particularly in Figure 2, the embodiment of the present invention comprises a body member 14 which defines an internal channel 15. When this embodiment is assembled in an engine as shown in Figure 1, the channel 15 provides a duct for the air/fuel mixture between the carburettor outlet 10 and the inlet manifold 11. The body member 14

may be made from aluminium, brass or any other suitable non-magnetic material.

The internal wall of the body member 14 is provided with a pair of inwardly extending steps 16 which are diametrically opposed with respect to the channel 15. A pair of magnet assemblies are positioned one on each of the steps 16, and are positively located in those positions by any suitable means (such as stops, locating keys, spring clips, clamps or the shaping of the internal walls of the body member ^" 14).

Each magnet assembly comprises the components illustrated in Figure 4, namely a block or rod magnet 30 and a pair of flat ferromagnetic (for example, soft iron) pole pieces 31 and 32. The rod magnet 30 is magnetised across its faces 33 and 34, so that when the pole pieces 31 and 32 are brought into contact with the faces ^" 33 and 34, respectively, of the magnet 30, the edges 31A and 32A of the pole pieces become the poles of the magnet assembly. The shape of the edges 31A and 32A is not critical. Normally the edges 31A and 32A will be rounded as shown in Figure 3 or flat as shown in Figure 2. The dimension w of the pole pieces 31 and 32 need only be a millimetre or so greater than the dimension b of the magnet 30 to establish the required magnet field structure of the resent invention. Normally the dimension b will be about 10 mm.

As indicated above, the magnet 30 must have a Curie temperature (the temperature at which the remanent magnetisation becomes zero) which is higher than the

maximum temperature likely to be experienced in the vicinity of the internal combustion engine. In a motor vehicle, this maximum temperature occurs shortly after the engine has been switched off after use, and is usually in the range of from 140°C to 160°C. The present inventor has successfully used rod magnets measuring 30 mm by 10 mm by 6 mm made from (a) a neodymium, iron and boron alloy having a Curie temperature of about 250°C, and (b) a cobalt and samarium alloy, having a Curie temperature of about 350°C. The former magnets, which had a magnet strength of 12,000 gauss, were obtained from Swift & Levic Magnets, of Sheffield, England. The latter magnets, which had a magnet strength of 10,500 gauss, were supplied by Hitachi Corporation, of Japan. Both types of magnets performed satisfactorily but the cobalt/samarium magnets are preferred because they have the higher Curie temperature.

The pole pieces 31 of the two magnet assemblies shown in Figures 1, 2 and 3 establish a magnetic field Bl in the channel 15, and the two pole pieces 32 establish a magnetic field B2. As shown in Figure 2, the lines of force of the magnetic field Bl are in the opposite direction to the lines of force of the magnetic field B2, but the lines of force of each field Bl and B2 are orthogonal to the direction of flow, through channel 15, of the air/fuel mixture leaving the carburettor outlet 10. Normally the spacing a between the two pole pieces 31 (and thus also between the two pole pieces 32) will be in the range from 10 mm to 20 mm, but this spacing may be varied to suit a particular engine and/or carburettor.

In the embodiment illustrated in Figure 2, the carburettor outlet 10 is provided with a flange 17 which is complementary to a flange 18 formed with or attached to the body member 14. The inclusion of a gasket 19 between the flanges 17 and 18 enables a gas-tight connection to be made between the carburettor outlet 10 and the body member 14 when the flanges 17 and 18 are clamped together by conventional means.

The connection between the body member 14 and the inlet manifold 11 is effected by making the lower region 14A of the body member 14 as a tubular structure of annular cross-section, with a groove 21 formed in its outer surface to receive an 0-ring 22. The diameter of the circular cross-section of the strip of material which forms the 0-ring 22 (that is, the diameter of each of the two sections shown by the reference numeral 22 in Figure 2) is such that, when the region 14A of the body member is inserted into a circular aperture 20 of the inlet manifold 11, a seal is established between the region 14A and the wall of the aperture 20 by the 0-ring 22. A sealing compound (for example, a silicone sealing compound) may be used to facilitate the establishment of this seal. Since the inlet manifold of an internal combustion engine is normally kept at a relatively cool temperature, the 0-ring 22 may be a conventional neoprene 0-ring.

It should be apparent that any other suitable means of connecting the body member 14 to the carburettor outlet 10 and to the inlet manifold 11 in a gas-tight manner may be used instead of the arrangement illustrated in Figure 2.

In the arrangement illustrated in Figure 2, an external step 23 at the upper end of the tubular end region 14A of the body member ensures that the body member cannot be inserted into the inlet manifold to such an extent that the 0-ring 22 is at least partially inside the wall of the inlet manifold. In other constructions of the body member 14, two of which are illustrated in Figure 5, the body member is provided with a pair of legs 25 which are screwed into threaded apertures in the base of the body member 14. The screw thread connection enables the length of the legs 25 projecting from the body member 14 to be adjusted so that when the legs 25 and the lower region of the body member 14 (with an 0-ring in the groove 21) are inserted into the aperture 20 of the inlet manifold, the legs act as spacers when they come into contact with the inner face of the lower wall of the inlet manifold 11 opposite the aperture 20.

Many carburettors have a separate primary and secondary air/fuel mixture outlet. With such carburettors, it is convenient (but not essential) to adopt either the arrangement shown in Figures 6 and 7, or the arrangement illustrated in Figure 8.

The partly schematic, partly sectional arrangement of Figure 6 shows how a body member 44 containing two separate pairs of magnet assemblies is mounted between a carburettor 45 and the inlet manifold 11 of the internal combustion engine. The pairs of magnet assemblies provide the magnetic fields Bl and B2 for each of the carburettor

outlets 10. An air cleaner 46 is shown mounted on top of the carburettor 45 in Figure 6.

In the alternative arrangement for a twin-outlet carburettor, illustrated in Figure 8, a central magnet assembly, comprising rod magnet 80 and ferromagnetic pole pieces 81 and 82, is used to provide, with respective outer magnet assemblies as described above the magnetic fields Bl and B2 for the primary and secondary air/fuel mixture outlets of the carburettor.

Similar arrangements to those shown in Figures 7 and 8 may be used with a central fuel injection system, in which two jets of fuel are provided directly to the inlet manifold of the internal combustion engine.

If the strengths of the magnetic fields Bl and B2 are to be varied, the bar magnets are replaced with the pole pieces of electromagnets. The electromagnets are operated with varying DC currents through their windings.

The present invention has been tested with engines of various sizes. Details of some of the tests and evaluations of the invention are provided in the following examples.

Example 1

A General Motors Holden vehicle, a 1964 "EH" Model motor car, designed to be run on fuel containing tetraethyl-lead as an anti-knocking agent, was run on unleaded fuel over a period of nine weeks. In this way, the fuel tank was

effectively washed with unleaded petrol ten times. At the end of this "washing" exercise, the fuel supplied to the engine was effectively lead-free.

With the first prototype equipment of the present invention mounted between the carburettor and the inlet manifold of the 6-cylinder engine, and with the magnet assembly pole pieces separated by 20 mm, the engine ran smoothly at all times. An exhaust gas analysis of the engine fitted with the first prototype of the invention showed that the requirements of Australian Design Rule No 37/00 had. been met. Even when operated under load, the engine exhibited no trace of knocking. It was concluded that essentially complete combustion of the unleaded petrol had been achieved.

Example 2

A Ford Motor Company vehicle, a 1970 Model "Cortina 440" motor car, was used in further tests of the present invention. No emission control equipment was fitted to the 4-cylinder, 1500 cc engine of this vehicle, which was run for nine months in the Canberra region of Australia using unleaded petrol only as the fuel. The cylinders of this engine had compression readings before this nine-months period of 965, 914, 793 and 965 kPa (corresponding to 140, 137, 115 and 140 p.s.i., respectively), and those compression figures were essentially unchanged at the end of this nine-months period.

Tests were then made of the on-road performance and the fuel usage, and the exhaust gas of the vehicle was

analysed, with and without a second prototype unit of the present invention attached to the engine. In this second prototype of the invention, the pole pieces establishing each magnetic field were spaced apart a distance of 7 mm and, to maintain a smooth flow of the air/fuel mixture, a generally conical taper to the gap between the pole pieces was established. The taper was created in a plate having a thickness of 9 mm, mounted immediately above the upper-most pair of pole pieces in the unit of the present invention. Tests with and without ^* the taper present showed an increase of 5 per cent in the horsepower generated by the engine when the conical taper was included.

The road tests showed that the engine operated smoothly with the second prototype unit attached, and with an apparently improved fuel economy. The exhaust gas analysis measurements were effected with the assistance of engineers from the National Roads and Motorists' Association Limited (NRMA). The cooperation of the NRMA in this analysis, and in the further exhaust gas testing reported in other Examples, is hereby acknowledged with gratitude. Table 1 summarises the results obtained from the exhaust gas analysis measurements.

Table 1 "Cortina" Exhaust Gas Analyses

Increase (I)

With or

Without present Decreased (D)

Parameter present invention in measured measured invention attached parameter

Hydrocarbon 1120 ppm 186 ppm (D) 83% emission

Carbon 6.56% 1.83% (D) 72% monoxide content Oxides of 3.74% 1.56% (D) 58% nitrogen content

Carbon 6.39% 13.08% (I) 52.7% dioxide content

These figures clearly illustrate the significant improvement in combustion that was achieved when the present invention was fitted to the engine of this vehicle.

Example 3

The vehicle used in this example was a Mitsubishi Motors "MAGNA TN" motor car, manufactured in 1987, and fitted with an automatic gearbox. The 2.6 litre, 4-cylinder engine of this vehicle was equipped with all the normal emission control equipment, including a catalytic converter. With the assistance of NRMA engineers, measurements of the exhaust gas composition of the engine were made (a) with

the catalytic converter present and the present invention not fitted to the engine of the vehicle; (b) with the catalytic converter removed and the present invention not fitted ^' to the engine; and (c) with the catalytic converter removed and with a unit of the present invention, constructed as shown in Figure 2, fitted between the carburettor and the inlet manifold of the engine. The results achieved are shown in Table 2.

Table 2

"Magna" Exhaust Gas Analyses

It was subsequently found that when these measurements were made, the carburettor jet was too large for this engine, with the result that the engine was running "rich". It is believed that, had a smaller carburettor jet been fitted, the present invention would have reduced, substantially, at least the hydrocarbon content of the exhaust gas.

Two road tests were made with this vehicle, after its engine had been fitted with the second prototype of this invention. Each road test involved a round trip of 199.7 km under essentially identical conditions, including 16 km of city traffic. The vehicle was driven in the same manner in each test, in the presence of two observers (one a director of the Institute of Automotive and Mechanical Engineers of Australia, the other the manager of the service department of the distributors of the vehicle in the Australian Capital Territory). The average fuel consumption was 17.44 litres. The expected fuel consumption for such a trip, based on figures published by NRMA for the same model vehicle, was 25.36 litres.

Example 4

The celebrated Australian artist Pro Hart owns two substantially identical Rolls Royce sedan cars, built in 1956. Each car has an engine of capacity 6.75 litres, to which fuel is supplied via a pair of carburettors. Experience over years of use of these motor vehicles shows that they have essentially identical fuel economies. Two units of the present invention, constructed as shown in Figures 2, 3 and 4 and with the pole pieces of the two magnet assemblies separated by 10 mm, were fitted between

respective carburettor outlets and the inlet manifold of one of the engines.

In a series of six test runs of each vehicle, driven in a similar manner over the same test route, the vehicle fitted with the unmodified Rolls Royce engine had an average fuel consumption rate of 25.5 litres per 100 kilometres. In contrast to this, the vehicle fitted with the two units of the present invention had an average fuel consumption rate of 13.0 litres per 100 kilometres. Subsequent analysis of the carbon monoxide content of the exhausts from these vehicles showed that the exhaust of the unmodified Rolls Royce engine had a carbon monoxide content of 9.0 per cent, whereas the engine equipped with the two units of the present invention had zero carbon monoxide in its exhaust gas.

Example 5

A unit of the present invention was evaluated in an engine test bed at Goodman Racing Developments, Sydney, Australia. The evaluation involved running a Ford 1600 cc, Formula 4, Cross-Flow racing engine in the test bed both with and without the present invention fitted to the engine. The test bed results of the brake horsepower developed by the engine, with similar loads and similar other operating conditions, are shown in Table 3.

Table 3

Power Comparisons - 1600 cc Ford Racing Engine

It will be seen that at the engine speeds most commonly used - in the range of from 2500 revolutions per minute (RPM) to 4000 RPM - there was an improvement in the horsepower developed by this engine.

Exhaust gas analyses of the engine produced the results shown in Table 4, demonstrating once more that improved combustion is achieved using the present invention.

Table 4 Exhaust gas analysis of 1600 cc Ford Racing Engine

Example 6

Lake Tuggeranong College in the Australian Capital Territory built two essentially identical vehicles, each powered by a 50 cc Honda engine, for use in the 1992 "Shell Mileage Marathon" held at the Amaroo Park Raceway, near Sydney, Australia. The engine of one of these vehicles was fitted with a unit of the present invention, in which the spacing between the pole pieces to establish the magnetic fields Bl and B2 was 1.7 mm.

In the "Shell Mileage Marathon", the vehicle equipped with the present invention took first place in Class D (Schools - commuter class - two persons in the vehicle) with a fuel consumption figure of 559.50 miles per gallon. The vehicle not equipped with the present invention was not

included in the top seventeen vehicles in Class D, meaning that its fuel consumption was less than 164.91 miles per gallon.

The performance in Class D of the vehicle equipped with the present invention was sufficient to give this vehicle first place, outright, in the Commuter Class, as its fuel consumption was better than any other "commuter" vehicle in the competition (some of which were vehicles entered by commercial automotive engineering organisations).

Example 7

An evaluation of the physical effect on the structure of the air/fuel mixture of the sequentially applied opposed magnetic fields was carried out by Prof B Luther-Davies and Dr A V Rode at the Laser Physics Centre of The Australian National University (Canberra, Australia). The equipment used for this evaluation is illustrated in Figure 9.

As shown in Figure 9, a laser beam 91, generated by a laser 90, was directed through an input window 92 and an output window 93 of a chamber attached to the inlet manifold of an internal combustion engine. The chamber had four ports, two of which contained the input window 92 and the output window 93. Another port 94 was connected to the inlet manifold of the engine. The fourth port 95 was connected directly to the output of a unit of the present invention 100, mounted underneath the SU carburettor 96 normally used to supply an air/fuel mixture to the engine.

The droplet structure of the air/ uel mixture was measured while the engine was operating, using a laser scattering technique (a) with two opposed magnetic fields in the unit 100 and (b) using a duplicated form of the present invention, with which the air/fuel mixture was subjected to four magnetic fields, in alternating opposed directions. The resultant particle size distribution for the two magnetic fields unit of the invention is shown by the solid curve in Figure 10. The dashed curve illustrates the departure from this droplet size distribution when four magnetic fields were applied to the air/fuel mixture. The technique used did not permit recordal of droplets having a diameter less than 3 microns.

This evaluation, the results of which were reported in The ANU Reporter, volume 29, No 12, of 12 August 1992, showed clearly that (1) the present invention acts to strongly reduce the number of large droplets in the air/fuel mixture and increase the number of small droplets, and (2) the change in the fuel droplet size distribution is large enough to significantly affect the combustion of the fuel.

Example 8

A further series of road tests and exhaust gas analyses were performed with the Mitsubishi "Magna" vehicle used in Example 3, equipped with a unit of the present invention. Again, NRMA engineers assisted in the tests and analyses.

With full polution control equipment fitted to the vehicle, the road test showed that at a constant speed of 60 km per hour, the fuel consumption was 14.3 litres per 100

kilometres (19.68 miles per gallon), and at a constant speed of 100 km per hour, the fuel consumption was 12.7 litres per 100 kilometres (22.22 mpg). With the catalytic converter removed, and with the unit of the present invention attached, the fuel consumption figures at constant speeds were measured at (a) 60 km per hour - 9.32 litres per 100 kilometres or 30.24 mpg; (b) 80 km per hour - 6.64 litres per 100 kilometres or 42.47 mpg; amd (c) 100 km per hour - 7.75 litres per 100 kilometres or 36.26 mpg.

The exhaust gas analysis, performed at the ACT Government Vehicle Testing Station at Dickson in the Australian Capital Territory, conducted with the catalytic converter removed and the present invention fitted to the engine, gave the following average readings when the engine was idled at 900 RPM (the maximum permissible values are shown in parentheses after each reading): (a) hydrocarbon content: 68 ppm (350 ppm); (b) carbon monoxide content: 0.7 per cent (3.5 per cent). Thus, set to idle at 900 RPM, this vehicle complied with the emission control requirements of Australian Design Rule No 37/00 without the need for a catalytic converter.

Reducing the idle speed to 600 RPM, at which rate the engine did not idle smoothly, resulted in an increase of the hydrocarbon content of the exhaust gas to 178 ppm (still well below the maximum permissible level) and an increase in the carbon monoxide content to 3.74 per cent (slightly above the maximum permissible level of 3.50 per cent).

These examples illustrate that the use of the present invention improves combustion in an internal combustion engine, to reduce pollutants in the exhaust gas of the engine and also to improve the fuel economy of the engine. It has also been found that use of the present invention with unleaded petrol can also reduce the production of hydrogen sulphide in the exhaust gas of an internal combustion engine.

It will be clear to automotive engineers that although specific embodiments of the present invention have been illustrated in the accompanying drawings and described above, variations to, and modifications of, those embodiments may be made without departing from the present inventive concept. Among such modifications and variations are the use of the present invention with "leaded" petrol, and possibly with two-stroke engines and the internal combustion engines used to power aircraft (neither of these last two uses has yet been tested).