A SECONDARY FLUID FOR ENGINES

Abstract

A secondary fluid is provided for use in an internal combustion engine that burns a primary fuel. The secondary fluid comprises about 15 vol % to about 30 vol % of alcohol; and about 0.0025 vol % to about 0.5 vol % of a lubricity enhancer which optionally is a castor oil. The secondary fluid is a thermodynamically stable microemulsion with water being the continuous phase.

Claims

1. A secondary fluid for use in an internal combustion engine that burns a primary fuel, the secondary fluid comprising: about 15 vol % to about 30 vol % of alcohol; and about 0.0025 vol % to about 0.5 vol % of a lubricity enhancer optionally comprising castor oil; with the remainder consisting essentially of water; wherein secondary fluid comprises a thermodynamically stable microemulsion with the water being a continuous phase.

2. The secondary fluid according to claim 1, wherein the water is degassed water.

3. The secondary fluid according to claim 1, wherein the lubricity enhancer is present in an amount in the range of from about 0.02 vol % to about 0.05 vol %

4. The secondary fluid according to claim 1, comprising: about 75 vol % to about 85 vol % water; about 18 vol % to about 25 vol % of alcohol; and about 0.04 vol % of a lubricity enhancer optionally comprising castor oil.

5. The secondary fluid according to claim 1, wherein the lubricity enhancer is a triglyceride.

6. The secondary fluid according to claim 5, wherein the triglyceride is a polar triglyceride which is castor oil.

7. The secondary fluid according to claim 6, wherein the amount of castor oil is such that the specific gravity of the water/alcohol (at ambient temperature and pressure) is matched to the specific gravity of castor oil (at ambient temperature and pressure).

8. The secondary fluid according to claim 1, wherein the alcohol is selected from methanol, isopropanol, propanol, 2-butanol, n-butanol and ethanol.

9. The secondary fluid according to claim 8, wherein the alcohol is methanol.

10. (canceled)

11. A storable secondary fluid combustible in an internal combustion engine but substantially non-flammable outside the engine, said secondary fluid consisting essentially of a two-phased fluid of: about 65 vol % to about 84.9975 vol % of water; about 15 vol % to about 30 vol % of alcohol; and about 0.0025 vol % to about 0.5 vol % of castor oil; which is a thermodynamically stable microemulsion with water being the continuous phase.

12. (canceled)

13. (canceled)

14. (canceled)

15. (canceled)

16. (canceled)

17. (canceled)

18. The secondary fluid according to claim 1, wherein the internal combustion engine is a diesel engine.

19. The secondary fluid according to claim 1, wherein the secondary fluid is not intended to be contactable with the primary fuel in the combustion chamber.

20. (canceled)

21. The storable secondary fluid according to claim 11, wherein the water is degassed water.

22. The secondary fluid according to claim 2, wherein the lubricity enhancer is present in an amount in the range of from about 0.02 vol % to about 0.05 vol %.

23. The storable secondary fluid according to claim 21, wherein the lubricity enhancer is present in an amount in the range of from about 0.02 vol % to about 0.05 vol %.

24. The secondary fluid according to claim 2, comprising: about 75 vol % to about 85 vol % water; about 18 vol % to about 25 vol % of alcohol; and about 0.04 vol % of a lubricity enhancer optionally comprising castor oil.

25. The secondary fluid according to claim 2, wherein the triglyceride is a polar triglyceride which is castor oil.

26. The storable secondary fluid according to claim 21, wherein the triglyceride is a polar triglyceride which is castor oil.

27. The secondary fluid according to claim 2, wherein the alcohol is methanol.

28. The storable secondary fluid according to claim 11, wherein the alcohol is methanol.

Description

BRIEF DESCRIPTION OF THE FIGURES

[0074] Embodiments of the invention will now be described with reference to the accompanying drawings which are not drawn to scale and which are exemplary only and in which:

[0075] FIG. 1 is a table showing the results from 50% Load dynamometer testing.

[0076] FIG. 2 is a table showing the results from 75% Load dynamometer testing.

[0077] FIG. 3 is a table showing the results from on road testing5 min Average testing.

[0078] FIG. 4 is a table showing the results from on road testing10 min Average testing.

[0079] FIG. 5 is a table showing Light Load testingLow Speed.

[0080] FIG. 6 is a table showing Light Load testingMedium Speed.

[0081] FIG. 7 is a table showing Engine data recorded at 50% load.

[0082] FIG. 8 is a table showing Engine data recorded at 75% load.

[0083] FIG. 9 is a table showing performance measures of an engine using an embodiment of the secondary fluid of the invention.

[0084] FIGS. 10 to 15 are tables showing the results from emulsion stability testing.

DETAILED DESCRIPTION OF EMBODIMENTS OF THE INVENTION

[0085] About 240 mL of methanol was combined with 1 ml of castor oil. The mixture was stirred until the castor oil was dispersed throughout the methanol liquid. Water was degassed at 28 inches of Hg for 1 hour. The degassed water was added to the methanol/castor oil blend to make up to 1 litre (about 759 mL of water). The resultant emulsion was allowed to stand overnight. The emulsion was cloudy and opaque white in colour. After 6 months, there was no evidence of separation of the emulsion.

[0086] The secondary fluid emulsion prepared according to the experiment above was added to a tank connected with a diesel engine. About 200 mL was added to the tank slowly by pouring. The engine was started and diesel fuel was corn busted to power the engine. Intermittently, the secondary fluid was pulled into the air intake under the influence of the engine management system. When the secondary fluid was to be injected, the fluid was pulled from the tank via a hose and injected by a nozzle just prior to the combustion chamber.

[0087] The water in this secondary fuel is thought to be useful for cooling. The water is thought to lower intake air charge temperature and provides significant cooling and in some cases significant delay of the initial combustion process. Water may also help to prevent the deleterious effect of premature ignition of the alcohol fuel in relation to the engine cycle. Water injection on its own is known to lower NOX production in diesel engines, while also reducing exhaust gas temperature. Water vapour when added at the correct ratio essentially crowds out space for air in the engine cylinder. Somewhat lowering the chance for oxygen and nitrogen in the cylinder creating NOx emissions during combustion.

[0088] The alcohol in the emulsion is thought to be useful for further reducing NOx production by changing the fuel reactivity when combusted along with diesel fuel in the cylinder of the engine. Diesel fuel is quite reactive and as such tends to generate considerable NOx and N2O emissions. Having a homogeneous in cylinder mixture of low reactivity fuel (Alcohol) in testing has shown to dramatically lower NOx and N2O production. The Alcohol is also thought to allow for the spontaneous emulsion of the lubricity enhancer (which can be castor oil), whether it be natural or synthetic.

[0089] The castor oil in this emulsion is thought to be useful for engine lubrication and rust prevention of components in the inlet air path of the engine and combustion chamber, that would ordinarily be brought about by water or alcohol. Large amounts of the lubricity enhancer are thought to be not advantageous. In fact the opposite, particularly for emissions may be true. The smallest amount and droplet size of castor oil that satisfies the corrosion test while retaining lubricity is the aim in the formulation.

[0090] This secondary fluid according to an embodiment can be used for several reasons: [0091] 1) Lubricate, protect and clean the inlet/intake manifold, cylinder head, combustion chamber, cylinder bore and piston/s. (Typically, at 75,000 kms or sooner a modern diesel will have intake blockage occurring). [0092] 2) Cool an engine and reduce exhaust gas temperature (NOx emissions reduce with lower combustion temperature). [0093] 3) Add engine power by various percentages depending on quantity injectedthe engine power could increase by about 2, 5 or 8% as a minimum increase. However, higher powers could be achieved. [0094] 4) Help extend the life of the diesel particulate filter (DPF) and various exhaust components by lowering soot emission and reducing DPF regeneration frequency. [0095] 5) Act as a partial fuel that is a much cleaner alternative to diesel.

[0096] In use, the secondary fluid can be pumped under pressure and timed for precise injection when the engine is under high load (that is, burning lots of fuel and creating lots of heat). The increase in heat unfortunately increases NOx emissions. At a certain pre-determined elevated exhaust or cylinder temperature the secondary fluid could be injected into the inlet manifold of the engine. The injection can be any type of injection including direct injection or fumigation. In embodiments, the diesel fuel quantity could be reduced and the secondary fluid (carrying its own energy from the methanol) could be injected to match the reduced energy content from the subtracted diesel. Theoretically the engine would receive the same total amount of energy, create very similar power; however, receive the cooling and lubricating effects of the secondary fluid, while burning a certain percentage of cleaner fuel (methanol) and lowering overall emissions.

[0097] The benefits of manifold injection (after the air filter) may allow for cleaning carbon, etc, from the manifold that is left over from the combustion process of diesel fuel and mixed with engine oil vapour that is drawn back into the intake manifold and engine via the exhaust gas recirculation valve and crank case breather system. When wet intake manifold injection is utilised (could be a single injector, one for each cylinder or more in any location in the intake manifold) this allows the present fluid to come into contact with recent deposits of carbon and engine oil etc. These deposits can in principle be simply washed away by the liquid, ingested by the engine and expelled through the exhaust. Conversely when using a dry-type intake manifold with direct cylinder injection (could be a diesel or gasoline engine) there is no washing and the carbon and oil etc builds up over time eventually blocking the intake manifold, EGR and cylinder head (Ports and valves)

[0098] It is thought that if the secondary fluid according to various embodiments is allowed to enter via the engine inlet valve/s naturally it will lubricate, cool and clean the inlet valve/s. This may also allow an easy installation/retrofit on engines that are already built and out there being used now.

[0099] During inductionaround 180 degrees of crankshaft rotation(one complete stroke of a four-stroke engine cycle) it is thought that the secondary fluid will be in contact will an extremely hot cylinder walls and pistons. Following this, another 180 degrees, the compression stroke will occur and further polymerization in the secondary fluid will potentially happen as the temperature begins to increase. After this comes combustion/power stroke which will elevate temperature and pressure considerably, and the lubricity enhancer of the secondary fluid is thought to further polymerize and/or combust. After that, a further 180 degrees on the exhaust stroke (where it is suspected (but not yet known)) that there is little lubrication that takes place here although some) the secondary fluid will eventually be expelled, and the procedure starts again.

Example 1Emulsion Stability Comparison with Varying Alcohol and Synthetic Castor Oil Content

[0100] Water has a high heat of vaporisation and is therefore an excellent candidate for engine heat management when incorporated in a secondary fuel emulsion. Water contains dissolved gasses such as O2, N2 and CO2. Some of which lead to rust and corrosion of various metals that are found in diesel engines, engine induction systems or injection equipment. Water on its own has a poor ability to lubricate. An ideal, predominantly aqueous secondary fuel should be a stable emulsion that contains low amounts of dissolved gases, an ability to reduce rust and corrosion and have a lubricity factor. It should have a high ability to cool the engine intake charge and add an alternate clean fuel source, such as short chain alcohols. The secondary fuel should not significantly negatively affect exhaust emissions or damaging delicate exhaust sensors or control equipment.

[0101] Secondary fuels, during shipping, or when used in vehicles will be subject to vibration or periods of long standing. It is important the present emulsion does not allow oil to settle, have significant amounts present on the surface or create foaming. This will ensure effective use within engine injection systems or in high pressure pumps.

[0102] Various embodiments of secondary fuel emulsions were visually examined for stability and foaming properties with varying ethanol, methanol and castor oil quantities.

[0103] Materials and Methods.

[0104] Without wishing to be limited by theory, it is thought that a water, alcohol and castor oil emulsion will be stable for long periods when the specific gravity of castor oil is about equal to the specific gravity of the combined water and alcohol components. Consideration was given to other gases phases in the reverse osmosis water.

[0105] Degassed reverse osmosis water was mixed with ethanol and methanol in varying volumes:

[0106] Ethanol Experiments:

[0107] RO degassed water by volume: 95 mls, 81 ml and 40 ml

[0108] Ethanol by volume: 5 ml, 19 ml and 60 ml

[0109] The ethanol was mixed with various amounts of synthetic castor oil with a stirrer at 300 RPM for 10 seconds. Synthetic castor oil quantities were varied, and the results examined in the following volumes: 1 ml, 0.5 ml, 0.25 ml and 0.05 ml.

[0110] A bittering agent was added to some samples.

[0111] Methanol Experiments:

[0112] RO degassed water by volume: 95 mls, 77 ml and 40 ml

[0113] Methanol by volume: 5 ml, 23 ml and 60 ml

[0114] The methanol was mixed with various amounts of synthetic castor oil with a stirrer at 300 RPM for 10 seconds. The vol % of castor oil is measured as a volume per 100 ml of injected secondary fluid. Synthetic castor oil quantities were varied, and the results examined in the following volumes 1 ml (1 vol %), 0.5 ml (0.5 vol %), 0.25 ml (0.25 vol %) and 0.05 ml (0.05 vol %).

[0115] The samples were each sealed and allowed to stand for varying time periods or until the emulsion failed. The emulsions were each vigorously shaken to detect any foaming. Visual inspections for separation were undertaken after time periods: 1 hr, 12 hr, 1 week and 1 month. Results can be found in the Tables of FIG. 10 to FIG. 15.

[0116] In embodiments in which water and alcohol was combined to have a specific gravity similar to castor oil (ethanol 19 ml and methanol 23 ml) performed well with low quantities of synthetic castor oil. It is noteworthy that the SG of the water alcohol mixture in the experimental emulsions is slightly lower than that of castor oil. This is to allow for any alcohol evaporation during use, and to slightly increases the Calorific Value of the secondary fluid with negligible negative effects on the resulting emulsions. Low quantities of castor oil are desirable for engine emissions and have been shown to satisfy the corrosion test while retaining a lubricating film.

[0117] As can be seen from the Tables of FIGS. 10 to 15, methanol slightly outperformed ethanol for emulsion stability. It is thought that this is because methanol is a shorter chain alcohol which has a better miscibility with water.

[0118] It is thought that the removal of gases from the RO water in these experiments creates a more stable emulsion by increasing the energy required for oil particles to come together. Further, there may be a slight mechanical effect bringing oil particles to the surface as some of these gasses rise from the emulsion. It is thought that once a successful spontaneous emulsion is made with degassed water there is a reduced likelihood of dissolved gases re-entering the emulsion. Further research should be conducted around the role of amphoteric alcohols in spontaneous oil/water emulsion formation.

Example 2Rust Evaluation of Mild Steel, Comparing Reverse Osmosis Filtered Water with an Embodiment of the Present Secondary Fluid

[0119] Engine intake water injection is a successful way to reduce NOx emissions and enhance brake power output. The advantages of water injection are due to its high enthalpy of vaporization and high specific heat capacity by which it absorbs heat from the in-cylinder mixture. Disadvantages of water injection include that water contains dissolved oxygen and therefore creates corrosion and rust.

[0120] A metal test piece has been found to have various corrosion effects at ambient temperature. Even the oxygen in the air causes rust and corrosion over time, and this is made particularly worse when the metal in an engine is washed with water (and optionally methanol) and then left to sit with the liquids covering these metal components. Water, when injected into an engine induction system and ultimately the engine combustion chamber will likely come into contact with mild steel and other metals. It is also likely small areas of pooling, particularly in the engine intake manifold will occur, creating corrosion or rust. These corrosion and rust particles over time will travel through the engine creating abrasion and engine wear. Further, should a non-atomized droplet of water come into contact with high temperature engine components the lubricating oil film will be negatively affected and accelerated engine wear is likely to occur.

[0121] It is therefore advantageous for the injection liquid to contain a resistance to corrosion/rust and a lubricity factor, while not significantly contributing to negative combustion emissions, or having the ability to damage exhaust system sensors or equipment. Castor oil has an affinity for metal and is thought to act not only as a lubricant, but also a corrosion inhibitor. This is particularly valuable during initial or dry start i.e. before crankcase oil has been splashed or pumped to the cylinder bore and underside of the piston.

[0122] A comparison of rust within a specific time frame was conducted between reverse osmosis filtered water (control) and the present secondary injection fluid on mild steel. Droplets of the reverse osmosis filtered water (control) and the present secondary injection fluid were applied to the mild steel and allowed to sit for 24 hours. The experiment was repeated 3 times over 3 consecutive days under ambient conditions.

[0123] Materials and Methods. [0124] reverse osmosis water. [0125] secondary injection fluid comprising: [0126] 80.96% Volume Reverse osmosis filtered and degassed water. [0127] 19.00% Volume Ethanol [0128] 0.04% Volume Synthetic Castor oil

[0129] A mild steel plate was prepared for rust analysis by surface sanding and preparation with isopropyl alcohol. Ambient weather conditions were recorded during the time of evaluation and recorded as temperature 14 to 16.2 degrees centigrade and 36 to 56% humidity.

[0130] Results

[0131] Significant rusting of mild steel was evident within the 3-day time period when testing with reverse osmosis water.

[0132] No rusting was evident with the present secondary injection fluid on mild steel. A protective and lubricating film appears to be evident, after water and alcohol evaporation.

Example 3Engine Operating Conditions Measured During Dynamometer 50% and 75% Load Testing

[0133] Engine operating conditions were examined comparing a standard diesel engine and the same engine fitted with a secondary fluid injection system for injecting two embodiments of secondary fluid labelled as CC-E and CC-M.

[0134] Materials and Method

[0135] A Standard WL-T 2.5 L Turbo Diesel Mazda engine was equipped with a data logging device to record various engine operating parameters. The vehicle was fitted with a computer-controlled injection system, which adjusts injection quantity based on engine air mass flow. A single injection nozzle was used to fumigate the engine intake manifold [0136] Standard Shell brand Diesel fuel was used. [0137] secondary injection fluid CC-M comprising by volume: [0138] 76.96% RO and degassed Water [0139] 23% Methanol [0140] 0.04% Synthetic Castor oil [0141] secondary injection fluid CC-E comprising by volume: [0142] 80.96% RO and degassed Water [0143] 19% Ethanol [0144] 0.04% Synthetic Castor oil

[0145] The vehicle was tested on a Mainline chassis dynamometer. Maximum torque was first measured at 2,900 RPM and the dynamometer rollers were set such that the RPM could not be exceeded. The engine power was brought up to produce 50% and then 75% of the maximum measured torque at 2900 RPM. The throttle position required to produce 50% and 75% maximum torque was maintained and measured.

[0146] The following was measured: [0147] Intake manifold air temperature. [0148] Exhaust manifold gas temperature. [0149] Engine intake air mass in grams of air per second.

[0150] Engine conditions were allowed sufficient time to stabilise before data was recorded. Peak engine KW power and NM torque were recorded and compared using a secondary fluid injection system ranging from 0 ml/minute to 150 ml/minute calculated based on engine air mass flow.

[0151] 50% Load Dynamometer Testing [0152] Secondary fluid CC-E and secondary fluid CC-M injection flow rate=75 ml per minute during all 50% load tests.

[0153] Results are shown in FIG. 7.

[0154] 75% Load Dynamometer Testing [0155] Secondary fluid CC-E and secondary fluid CC-M injection flow rate=150 ml per minute during all 75% load tests.

[0156] Results are shown in FIG. 8. The performance measured is shown in FIG. 9.

[0157] As can be seen from the Tables in FIGS. 7 to 9, air mass remained relatively constant, with the exception of with CC-E at 75% load. It is thought that this is because of water vapor taking up space in the engine intake path. Intake manifold temperature decreased significantly with both CC-M and CC-E. It is thought the larger water content in CC-E contributed more to cooling the intake charge. Exhaust gas temperature decreased significantly with CC-E and CC-M. It is noteworthy that the exhaust gas temperature decreased in a comparable rate to the intake air charge temperature. The larger content of water in CC-E appeared to offset the exhaust gas temperature even though it contains a higher overall calorific value.

[0158] Throttle position decreased, therefore diesel fuel required to make the same required torque was reduced. It is noteworthy that using CC-E the Diesel throttle position at 50% load was 4.7% lower.

[0159] Engine performance with CC-M and CC-E were both increased. It is seen that CC-M has a larger performance benefit. It is thought that CC-M has more favourable combustion characteristics in respect of KW and NM production when compared to CC-E.

Example 4Exhaust Emission Testing Comparing a Standard Diesel Engine, with Two Embodiments of the Secondary Injection Fluid

[0160] Diesel engines typically generate relatively high NOx exhaust emissions, particularly under moderate to high engine load. N.sub.2O emission production generally increases with engine load and are considered 300 times worse for global warming than CO.sub.2 emissions.

[0161] Exhaust gas emissions testing will be conducted comparing a standard diesel engine and the same engine fitted with an injection system injecting an embodiment of the secondary fluid of the present invention. It is thought that intake manifold fumigation style injection of the present secondary fluid Water/Alcohol/Castor oil emulsion will improve exhaust emissions, by lowering combustion temperature, creating a more homogeneous cylinder mixture and altering total fuel reactivity.

[0162] Materials and Method

[0163] A Standard WL-T 2.5 L Turbo Diesel Mazda engine was equipped with a data logging device to record various engine operating parameters. The vehicle was fitted with a computer-controlled injection system, which adjusts injection quantity based on engine air mass flow. A single injection nozzle was used to fumigate the engine intake manifold [0164] Standard Shell brand Diesel fuel was used. [0165] secondary injection fluid CC-M comprising by volume: [0166] 76.96% RO and degassed Water [0167] 23% Methanol [0168] 0.04% Synthetic Castor oil [0169] secondary injection fluid CC-E comprising by volume: [0170] 80.96% RO and degassed Water [0171] 19% Ethanol [0172] 0.04% Synthetic Castor oil

[0173] Standard testing was undertaken without secondary fluid. A control comprising 100% RO water injection as a secondary fluid was also tested on road.

[0174] The secondary fluid injection quantity was recorded for all dynamometer testing. Light load emission testing was conducted at various engine RPM with differing secondary fluid injection quantities. A portable Madur GA-21 plus exhaust gas analyser was used to measure emissions. The Madur GA-21 plus also measured averaged on road driving emissions over a repeated designated path with as similar a driving style as possible.

[0175] The vehicle underwent controlled engine load conditions of 50% and 75% load at 2,900 RPM on a 2WD Mainline chassis dynamometer. The vehicle diesel injection timing remained standard for all tests. Averaged emission test durations were 5 minute and 10 minutes. Soot testing was conducted at various operating conditions on a chassis dynamometer.

[0176] Hydrogen injection gas flow rate was constant at 95 litres per minute for all designated chassis dynamometer and low load tests.

[0177] Results

[0178] 50% Load Dynamometer Testing [0179] Secondary fluid CC-E and secondary fluid CC-M injection flow rate=75 ml per minute during all 50% load tests. [0180] Hydrogen flow rate=95 litres per minute

[0181] The results are shown in FIG. 1.

[0182] 75% Load Dynamometer Testing [0183] Secondary fluid CC-E and secondary fluid CC-M injection flow rate=150 ml per minute during all 75% load tests. [0184] Hydrogen flow rate=95 litres per minute

[0185] The results are shown in FIG. 2.

[0186] On Road Testing5 and 10 min Average Testing [0187] Secondary fluid CC-E and RO water injection flow rates were computer controlled between 0 and 150 ml per minute for all on road testing, based on engine air mass flow. The results are shown in FIG. 3 (5 min testing) and FIG. 4 (10 min testing).

[0188] Light Load TestingLOW SPEED [0189] Secondary fluid CC-E and secondary fluid CC-M injection flow rate=30 ml per minute during all low speed tests. [0190] Hydrogen flow rate=95 litres per minute.

[0191] Results are shown in FIG. 5.

[0192] Light Load TestingMEDIUM SPEED [0193] Secondary fluid CC-E and secondary fluid CC-M injection flow rate=80 ml per minute during all medium speed tests. [0194] Hydrogen flow rate=95 litres per minute.

[0195] Results are shown in FIG. 6.

[0196] Note: Diesel fuel rate was kept constant for all low load and low and medium speed tests. Any variance in engine RPM is considered a result of EGR flow effecting engine performance and or additional calorific value added to combustion from other fuel sources, such as the alcohol.

[0197] No appreciable difference in Soot emissions were detected across all dynamometer test results. It was noted that the test equipment operated for 30-40 seconds longer to perform the test when secondary fluid was added to the engine. It is though that the additional water vapor in the exhaust system played a role in slowing the emissions sampling rate. A different style of soot detecting device is recommended for future tests.

[0198] The standard NOx emission from an engine without the secondary fluid was 67 ppm for the 5 minute testing (FIG. 5) and 56 ppm from the 10 minute testing (FIG. 6). As can be seen from the Tables of FIGS. 5 and 6, during light load the injection of secondary fluid CC-E and CC-M both resulted in considerable reductions in NOx emissions. It is noteworthy that careful tuning of EGR flow and injection flow should be considered to balance any increase in N2O emission with reduction in CO2 emissions at this engine speed and load.

[0199] Hydrogen injection during light load with both Secondary fluid CC-E and secondary fluid CC-M showed a surprising low amount of NOx emissions. Hydrogen flow rate was constant for all tests and it is thought that the Hydrogen injection used in this testing will play a more significant role in reducing CO2 emissions at lower load. This is thought to be because of less dilution with intake air mass flow and the differential in ratio of diesel fuel injected in respect to hydrogen flow.

[0200] During on road testing NOx emission in both 5 minute and 10 minute testing showed significant reductions. It is noteworthy that the 10 minute road test showed an increase in CO2 emissions. It is thought this shows a slight discrepancy in traffic conditions or driving style. During 50% load dynamometer testing and 75% load dynamometer testing, NOx emission using both CC-E and CC-M showed a significant reduction. CC-E is particularly noteworthy in respect to N2O emissions at these engine loads.

[0201] It should be remembered that these experiments were undertaken as a proof of concept design, and significant improvements are expected when both systems are optimised in their design. For example, multi-port evenly distributed and timed injection will likely improve performance further. The current injection system is of the continuous flow type. It would be advantageous for both secondary fluid and hydrogen injection systems to be timed in relation to the engine induction stroke, resulting in less secondary injection fluid and hydrogen gas passing through the engine cylinder on valve overlap and into the exhaustfurther improving emissions and reducing total flow quantities required, particularly at low engine RPM. It is further expected that different configuration diesel engines will perform more favourably using CC-M in respect to N2O emissions and further testing should be conducted in this area.

[0202] It is to be understood that, if any prior art publication is referred to herein, such reference does not constitute an admission that the publication forms a part of the common general knowledge in the art, in Australia or any other country.

[0203] In the claims which follow and in the preceding description of the invention, except where the context requires otherwise due to express language or necessary implication, the word comprise or variations such as comprises or comprising is used in an inclusive sense, i.e. to specify the presence of the stated features but not to preclude the presence or addition of further features in various embodiments of the invention.

[0204] Any promises made in the present description should be understood to relate to some embodiments of the invention, and are not intended to be promises made about the invention as a whole. Where there are promises that are deemed to apply to all embodiments of the invention, the applicant/patentee reserves the right to later delete them from the description and does not rely on these promises for the acceptance or subsequent grant of a patent in any country.