Introduction This invention relates to a combustion engine filter and more particularly to an air intake filter comprising a pre- or secondary filter. The invention also relates to a method for improving the performance and longevity of a primary air filter with a pre- filter and to a method for reducing engine emissions and improving combustion engine performance.

Background of the Invention

Air intake filters are generally employed to prevent particulates from entering internal combustion engines. For example, the air intake filters in vehicles and plant equipment such as rock crushers can endure short lifespans due to the high level of ingress of particulates into the filter material resulting in the need for regular replacement of such filters at considerable cost. The air intake filters employed in military vehicles such as armoured personnel carriers (APC’s) and equipment in desert environments also endure a short lifespan with the result it can become necessary to frequently halt the APC to remove particulates from the air filter at excessively regular intervals e.g. as frequent as every 30km travelled which can seriously delay military progress. As military bases are typically located a distance of 80km apart, the halted APC can form an easy and exposed military target.

Moreover, as the filter cleaning process can take up to forty-five minutes, the APC is stationary for an extended period further increasing the military risk. More commonly, the air intake filters employed in conventional road vehicles such as cars and trucks also function inefficiently resulting in relatively high emission levels.

Separately but simultaneously, vehicle manufacturers are constantly seeking methods to reduce the level of volatile organic compound (VOC), diesel particulate matter, carbon monoxide and carbon dioxide emissions in all vehicles powered by combustion engines and, in particular, petrol and diesel combustion engines.

An object of the invention is to overcome at least some of the problems of the prior art.

Summary of the Invention

According to the invention there is provided an air intake filter for a combustion engine comprising:

a primary filter for filtration of particulate contaminants and

a pre-filter cover on the primary filter wherein the pre-filter comprises a fibreglass pre-filter selectable in accordance with the combustion engine to optimise engine performance.

Preferably, the fibreglass pre-filter comprises a fibreglass tissue or membrane. More preferably, the fibreglass tissue or membrane comprises a woven fibreglass tissue or membrane. Most preferably, the fibreglass tissue or membrane is selectable in accordance with the weave of the tissue or membrane. Preferably, the tissue fibreglass tissue has a grade from about 400 to about 800g/m ² . More preferably, the fibreglass tissue has a grade from about 500 to about 700g/m ² . Even more preferably, the fibreglass tissue has a grade from about 550 to about 650g/m ² . Most preferably, the fibreglass tissue has a grade of about 600g/m ² .

Preferably, the woven fibreglass fabric layer comprises a woven fibreglass fabric double layer.

Advantageously, the fibreglass tissue or membrane has a nominal thickness of about 90 microns.

Preferably, the fibreglass pre-filter is selectable from the group comprising Product Code 100F65E available from Beiyang Building Material Company Limited adapted for marine and heavy duty dust/pollen/harsh combustion engine applications, Product Code 102F65E available from Beiyang Building Material Company Limited for road vehicle combustion engine applications and Product Code 103F65E available from Beiyang Building Material Company Limited for industrial combustion engine applications. Advantageously, the fibreglass tissue or membrane is colour coded in accordance with the combustion engine.

In a further embodiment, the invention also extends to a pre-filter cover for use with a primary air intake filter for a combustion engine wherein the pre-filter comprises a fibreglass pre-filter selectable in accordance with the combustion engine to optimise engine performance. Preferably, the fibreglass pre-filter comprises a fibreglass tissue or membrane. More preferably, the fibreglass tissue or membrane comprises a woven fibreglass tissue or membrane. Most preferably, the fibreglass tissue or membrane is selectable in accordance with the weave of the tissue or membrane.

Preferably, the fibreglass tissue has a grade from about 400 to about 800g/m ² . More preferably, the fibreglass tissue has a grade from about 500 to about 700g/m ² . Even more preferably, the fibreglass tissue has a grade from about 550 to about 650g/m ² . Most preferably, the fibreglass tissue has a grade of about 600g/m ² .

Preferably, the woven fibreglass tissue comprises a woven fibreglass fabric double layer.

Advantageously, the fibreglass tissue or membrane has a nominal thickness of about 90 microns.

Preferably, the fibreglass pre-filter is selectable from the group comprising Product Code 100F65E available from Beiyang Building Material Company Limited adapted for marine and heavy duty dust/pollen/harsh combustion engine applications, Product Code 102F65E available from Beiyang Building Material Company Limited for road vehicle combustion engine applications and Product Code 103F65E available from Beiyang Building Material Company Limited for industrial combustion engine applications. Advantageously, the fibreglass tissue or membrane is colour coded in accordance with the combustion engine.

The invention also extends to a method for improving the performance of a primary air filter for a combustion engine comprising selecting a fibreglass pre-filter cover in accordance with the combustion engine and attaching the pre-filter to the primary filter to cover the primary filter and optimise engine performance.

Preferably, the pre- filter is attached to the outer surface of the primary filter. More preferably, the pre- filter is attached to the outer surface of the primary filter and covers the primary filter.

Preferably, the fibreglass pre-filter comprises a fibreglass tissue or membrane. More preferably, the fibreglass tissue or membrane comprises a woven fibreglass tissue or membrane. Most preferably, the fibreglass tissue or membrane is selectable in accordance with the weave of the tissue or membrane.

Preferably, the fibreglass tissue has a grade from about 400 to about 800g/m ² . More preferably, the fibreglass tissue has a grade from about 500 to about 700g/m ² . Even more preferably, the fibreglass tissue has a grade from about 550 to about 650g/m ² . Most preferably, the fibreglass tissue fabric has a grade of about 600g/m ² .

Preferably, the woven fibreglass tissue comprises a woven fibreglass fabric double layer. Advantageously, the fibreglass tissue or membrane has a nominal thickness of about 90 microns.

Preferably, the fibreglass pre-filter is selectable from the group comprising Product Code 100F65E available from Beiyang Building Material Company Limited adapted for marine and heavy duty dust/pollen/harsh combustion engine applications,

Product Code 102F65E available from Beiyang Building Material Company Limited for road vehicle combustion engine applications and Product Code 103F65E available from Beiyang Building Material Company Limited for industrial combustion engine applications.

Advantageously, the fibreglass tissue or membrane is colour coded in accordance with the combustion engine. In a further embodiment, the invention also extends to a method for reducing engine emissions and improving combustion engine performance comprising selecting a fibreglass pre-filter cover in accordance with the combustion engine and attaching the pre-filter to the primary filter to cover the primary filter and reduce emissions and optimise engine performance.

Preferably, the pre- filter is attached to the outer surface of the primary filter. More preferably, the pre- filter is attached to the outer surface of the primary filter and covers the primary filter. Preferably, the fibreglass pre-filter comprises a fibreglass tissue or membrane. More preferably, the fibreglass tissue or membrane comprises a woven fibreglass tissue or membrane. Most preferably, the fibreglass tissue or membrane is selectable in accordance with the weave of the tissue or membrane.

Preferably, the fibreglass tissue has a grade from about 400 to about 800g/m ² . More preferably, the fibreglass tissue has a grade from about 500 to about 700g/m ² . Even more preferably, the fibreglass tissue has a grade from about 550 to about 650g/m ² . Most preferably, the fibreglass tissue has a grade of about 600g/m ² .

Preferably, the woven fibreglass tissue comprises a woven fibreglass fabric double layer.

Advantageously, the fibreglass tissue or membrane has a nominal thickness of about 90 microns.

Preferably, the fibreglass pre-filter is selectable from the group comprising Product Code 100F65E available from Beiyang Building Material Company Limited adapted for marine and heavy duty dust/pollen/harsh combustion engine applications, Product Code 102F65E available from Beiyang Building Material Company Limited for road vehicle combustion engine applications and Product Code 103F65E available from Beiyang Building Material Company Limited for industrial combustion engine applications. Advantageously, the fibreglass tissue or membrane is colour coded in accordance with the combustion engine.

The supplementary pre-filter cover of the invention improves the efficiency of and extends the useful life of conventional air filters thus enabling continued operation of plant equipment, vehicles, military equipment and the like without the need to halt operation to clean and/or replace air filters. For example, rock crushers and vehicles can operate efficiently for extended periods with reduced maintenance and downtimes while military vehicles such as APC’s can travel for increased distances between bases in desert conditions without the need to interrupt the journey to wash and/or replace air filters thereby improving military efficiency and safety.

In petrol and diesel road vehicles, emissions are reduced and combustion efficiency is improved while filter longevity is optimised.

The supplementary air filter cover or pre-filter of the invention can be incorporated into conventional air filters during manufacture or retrofitted to pre-existing air filters.

Brief Description of the Drawings

The invention will now be described, by way of example only, with reference to the accompanying drawings and Examples in which: Figure 1 is a perspective view from above and one side of a cylindrical air intake filter fitted with a double layer of a supplementary/secondary/pre- filter or filter cover; Figure 2 is a perspective view from above and one side of a flat air intake filter fitted with a double layer of a supplementary/secondary/pre- filter or filter cover;

Figures 3(a) to 3(c) are sequential perspective views from above and one side of a primary cylindrical air intake filter being retrofitted with the double layer of a supplementary/secondary/pre- filter or filter cover;

Figures 4(a) to 4(b) are sequential perspective views from above and one side of a flat air intake filter being retrofitted with the double layer of a

supplementary/secondary/pre- filter or filter cover;

Figure 5 is a perspective view from above and one side of an air intake filter of the prior art without a filter cover of the invention with particulate matter in the form of dust, pollen, debris and the like schematically represented as adhering to the air intake filter and the direction of airflow indicated by the arrows;

Figure 6 is a perspective view from above and one side of the air intake filter of Figure 5 with the accumulated particulate matter on the filter restricting airflow with the reduced airflow indicated by a smaller arrow; Figure 7 is a perspective view from one side of the cylindrical air intake filter fitted with a double layer of a supplementary/secondary/pre- filter or filter cover of Figure 1 with the enhanced airflow indicated by arrows and the particulate matter remaining airborne due to the absence of electrostatic attraction as a result of the static neutral filter cover;

Figure 8 is a pie chart of the improvement achieved with the pre-filter of the invention compared with a standard air intake filter employed in various vehicles namely various Toyota, TCM and Yale forklifts and a Toyota Fliace van;

Figure 9 is a Table Showing VOC changes with different filters in the different vehicles of Example 2;

Figure 10 is a graph of the results of the comparative efficiency test for Filter 1 vs Filter 4 in Example 5, and

Figure 11 is graph of the results of the comparative efficiency test for Filter 3 vs Filter 2 in Example 5. Detailed Description of the Invention

Figure 1 shows a perspective view from above and one side of a pre-filter generally indicated by the reference numeral 1 in the form of a secondary or supplementary filter cover 2 mounted on a cylindrical primary air intake filter 3 of a vehicle powered by an internal combustion engine. As shown in the drawing, the air intake filter 3 is made up of a cylindrical casing 4 having a filter membrane 5 (e.g. paper or cotton) fitted thereto. The filter membrane 5 is in turn covered with a double layer 6 of the suitably sized and shaped fibreglass filter cover 2 to protect the filter membrane 5. The filter cover 2 improves the life of the air intake filter 3 and also prolongs the life of the air intake filter 3.

Figure 2 shows a perspective view from above and one side of a second

embodiment of the invention in the form of a box-like or flat primary air intake filter fitted 3 with a double layer of a pre-filter cover 2. Like numerals indicate like parts. However, as will be appreciated by those skilled in the art, in the present

embodiment, the casing 4 is substantially box-like in shape and the filter membrane 5 is inserted in the casing 4.

The pre-filter cover 2 can be incorporated into a primary filter 3 during manufacture of the primary filter 3 or, if desired, retrofitted to the primary filter 3. Figures 3(a) to 3(b) show sequential perspective views from above and one side of the primary cylindrical air intake filter 3 of Figure 1 being retrofitted with the double layer of the filter cover 2. As shown in the drawing, the pre-filter cover 2 is wrapped about the primary filter membrane 5 to form a first layer of the double layer 6 on the primary filter 3 and is secured in position by adhesive tape 7 at its edges to ensure an air- tight fit to the primary filter 3. The process is then repeated with a second layer of the pre-filter cover 2 to form the double layer 6 - preferably with the centre joints of the double layer 6 overlapped for optimal results. Figures 4(a) to 4(b) are sequential perspective views from above and one side of the flat air intake filter 3 of Figure 2 being retrofitted with the double layer 6 of the pre-filter cover 2 in a similar manner. As shown in the drawings, a double layer 6 of the pre-filter cover 6 is placed over the box-like casing 4 and the filter membrane 5 is then inserted into the casing 4 so that the double layer 6 is disposed between the casing 4 and the filter membrane 5. Excess pre-filter cover 6 can then be trimmed as required.

If desired, the pre-filter cover 2 can also be held in place with adhesive or bands instead of adhesive tape.

In use, air flow through the primary filter 3 is enhanced due to a bespoke static neutral and smooth surface created by the filter cover 2 on the primary filter 3.

Moreover, air is ever present between the filter cover 2 and primary filter 3 and is free from resistance. Constant presence of air between the filter cover 2 and the primary filter 3 also enhances air flow through the primary filter 3. Moreover, eddy effects are greatly reduced due to the smooth surface while air flow is surprisingly less restricted so that fuel combustion is actually enhanced thereby reducing VOC emissions, diesel particulate matter and fuel consumption. The working life of the primary air filter 3 is also extended.

As shown particularly in Figures 5 to 7, where no filter cover 2 of the invention is employed, particulate matter in the form of dust, pollen, debris and the like 7 adheres to the air intake filter 3. Build-up of the particulate matter 7 on the air intake filter 3 therefore reduces airflow (see Figure 6). Conversely, as shown in Figure 7, the pre- filter 1 of the invention ensures that the particulate matter 7 remains airborne due to the absence of electrostatic attraction created by the pre-filter 1 i.e. the pre-filter 1 remains neutral thereby enhancing airflow so that any particulate matter 7 entering the air intake filter 3 is in fact expelled from the air intake filter 3. Accordingly, airflow can be enhanced for up to twelve times longer.

Generally, the filter cover 2 is formed from a fibreglass material such as fibreglass tissue sheets. The filter cover 2 of the invention is formed from a woven fibreglass fabric having a grade from about 400 to about 800g/m ² , more preferably from about 500 to about 700g/m ² , most preferably from about 550 to about 650g/m ² and optimally about 600g/m ² . The fibreglass tissue material has a nominal thickness of about 90 microns.

More particularly, the bespoke static neutral and smooth surface required for the filter cover is achieved through the use of fibreglass materials selected as defined in Table 1 adapted to optimally perform in accordance with four use categories namely industrial applications with plant machinery, marine applications, heavy duty dust/pollen/harsh environment applications e.g. with rock crushing equipment and road vehicle applications.

It has been found that a woven fibreglass fabric having the general characteristics outlined in Table 1 achieves optimal results

Table 1

General Fibreglass Specification

The Applicant has found that by adjusting the characteristics of the woven fibreglass tissue the filter cover 2 performance can be optimised and tailored for each of the four general applications described above. More particularly, the Applicant has found that by selectively adjusting the weave pattern of the woven fibreglass tissue performance of the filter cover formed from the woven fibreglass tissue can be optimised as required in accordance with the end use. Suitably woven fibreglass tissue materials are available from Beiyang Building Material Company Limited. For example, Product Code 100F65E is adapted for use in the marine and heavy duty dust/pollen/harsh environment applications, Product Code 102F65E is adapted for use in road vehicle application while Product Code 103F65E is adapted for use in industrial applications. The filter covers 2 formed from the fibreglass materials as described above effectively filter dust particles to a size of 5 microns.

Each of the fibreglass tissue materials can be colour coded as required to distinguish the bespoke applications and can be cut to size as required.

As shall be explained more fully below, surprisingly, it has been found that the pre- filter 1 results in an unexpected reduction in the level of volatile organic compound (VOC), diesel particulate matter, carbon monoxide and carbon dioxide emissions in vehicles powered by internal combustion engines fitted with the device of the invention whilst also improving fuel efficiency, extending engine life, reducing maintenance downtime, improving cost-efficiency and minimising landfilling.

In particular, the tailored filter covers of the invention achieve a reduction in VOC emissions of up to 89%, a reduction in diesel particulate matter of up to 25%, a reduction in fuel consumption reduced by up to 14.5%, a reduction in carbon monoxide emissions in diesel and petrol engines, a reduction in carbon dioxide emissions in petrol engines, up to a nine fold increase in air filter working life and dramatically increased engine performance in petrol engines. The reduction achieved in VOC emissions reduces the greenhouse effect combating climate change while the reduction in diesel particulate matter emissions reduces smog and associated deaths. Similarly, the reduced fuel consumption reduces the reliance on natural resources while the increase in air filter life reduces landfill.

As fibreglass is an organic based material, the filters of the invention are therefore environmentally friendly.

The retrofitting of an existing air filter with a filter cover of the invention therefore has a significant positive impact on the efficiency, capacity and restriction parameters of air filters - the filters fitted with the filter cover of the invention have increased filtration efficiency and capacity.

Example 1 : Reduction of VOC level emissions in diesel engines in a van and forklift vehicles

The vehicles tested in this sample were Diesel Forklifts and one Van. The age of the vehicles ranged significantly as did the hours on each machine. In addition to this the engine types and sizes also varied. Parameters recorded included make and model, engines size and type, age/hours, temperature and filters.

Upon vehicle arrival, calibration of a Minirae 3000 Portable Handheld VOC monitor was checked and verified. A new Air filter was applied to the nozzle, this was primarily for filtering particulate matter and preventing any residual moisture entering the PID. Temperature was recorded on each machine upon initial start-up and then again, several minutes later when the engine had‘warmed up’, the reason for the varied temperature monitoring was to determine if there was a significant difference in VOC’s emitted upon start up and compare that with the VOC’s emitted during warmer engine temperatures. Upon identification of all test vehicles, each machine was identified by make and model of vehicle, engine model and size, age of engine and hours recorded on the machine during the test. Make and model of the van was recorded in conjunction with miles on the odometer and age of vehicle.

The method of VOC monitoring was that the nozzle of the PID was placed at the end of each exhaust at the same point for all vehicles to ensure the same conditions were met for each test range on each vehicle. VOC’S were monitored until the figure recorded on the PID stopped and held the same figure for 3 seconds or the figure on the display began to drop. At this point the highest figure was recorded. This method of recording was applied for all tests. The tests were recorded for air intake filters with and without the pre-filter cover of the invention and the differences in VOC emissions were recorded.

Figure 8 shows a pie chart of the improvement achieved with the pre-filter of the invention compared with a standard air intake filter. The improvements were significant with reductions in VOC emissions ranging 21.27% to almost 80%.

Example 2: Reduction of VOC level emissions in diesel and petrol engines in diesel buses and lorries, diesel cars and petrol cars. The calibration of a Minirae 3000 Portable Handheld VOC monitor was checked and verified. A new Air filter was applied to the nozzle, this was primarily for filtering particulate matter and preventing and residual moisture entering the PID.

Temperature was recorded on each machine upon initial start-up and then again, several minutes later when the engine had‘warmed up’, the reason for the varied temperature monitoring was to determine if there was a significant difference In VOC’s emitted upon start up and compare that with the VOC’s Emitted during warmer engine temperatures. Upon identification of all test vehicles, each machine was identified by make and model of vehicle, engine model and size, age of vehicle and miles or kilometres recorded on the machine during the test. The method of VOC monitoring in Diesel vehicles was that the nozzle of the PID was placed at the end of each exhaust. It was placed at the same point for all vehicles to ensure the same conditions were met for each test range on each vehicle. For petrol vehicles, the monitor was held approximately 5cm from the end of the exhaust, this is because the petrol vehicles expel significantly more moisture than the diesel vehicles and have the potential to cause moisture damage to the monitoring equipment. The air filter was changed much more regularly when measuring the petrol vehicles to prevent damage. VOC’S were monitored until the figure recorded on the PID stopped or held the same figure for 3 seconds or the figure on the display began to drop. At this point the highest figure was recorded. This method of recording was applied for all tests.

The diesel lorry and bus vehicles tested were as follows:

05 MN 6265 - Scania 12L;

06 D 120303 - Scania 12L; 00 D 75676 - Volvo 7L;

01 D 27572 - Scania 9L.

The diesel cars tested were as follows:

141 D 31215 - Volkswagen Passat;

LJZ 72 - Audi Q5;

08 MN 8203 - Peugeot 207.

The petrol cars tested were as follows:

00 WW 7505 - BMW 3L;

07 D 29462 - Volkswagen Passat;

161 Ford Fiesta;

06 MN 1641 - Corsa 1 L; Analysis was performed on each vehicle with and without the pre-filter of the invention. The results are shown in Figure 9.

All changes in VOC Concentration were measured against the worst VOC concentration for the vehicle being measured with the worst VOC releases coming from some of the older vehicles - the 00 D 75676 Volvo 7L recorded a high VOC of 871.1 ppm with no filter and the 01 D 27572 Scania 9L recorded a high VOC of 1103ppm with an old dirty filter. These vehicles, although the worst offenders initially, recorded the best percentage change in VOC levels when the VOC’s were measured with the pre-filter of the invention on a primary filter. The 00 D 75676 Volvo 7L recorded a 99.82% improvement from the worst recording to the best VOC recording with the invention. The 01 D 27572 Scania 9L recorded a 65.73% improvement from the worst recording to the best VOC recording with the invention.

When comparing the vehicles, it was noted on the 05 MN 6265 Scania 12L engine and 06 D 120303 12L engine that the VOC levels were similar initially. However, the vehicle 06 D 120303 has been retrofitted with an Ad Blue system. Although no significant difference in VOC level was found between the vehicle with AdBlue and the Vehicle without AdBlue, both Vehicles showed significant improvements with use of the invention.

Some of the lowest VOC’s came from the petrol vehicles, with the 07 D 29462 Volkswagen Passat 1 ,6L recording a high VOC of 29.8ppm with no filter installed. This VOC was further reduced to 3.3ppm upon installation of the pre-filter of the invention, a significant improvement of 88.93% from the high VOC. Similarly, reductions of VOC’s were encountered in all petrol vehicles.

Vehicle 08 MN 8203 when tested for VOC’s, showed a 36.01 % improvement from the worst VOC recording to recording with the pre-filter of the invention. This vehicle was also inspected for carbon monoxide emissions and the results showed that it had a carbon monoxide level of 0.66g/kg with the original filter installed which reduced to 0.47 g/kg with the pre-filter of the invention. It is believed that the improvement was as a result of the diesel combusting better with the use of the pre-filter of the invention. Significantly, the reduction in CO level has allowed the vehicle which was only just within the compliance limit for Euro 3 emissions criteria become compliant with both Euro 5 and Euro 6 standard of 0.5 mg/kg of CO emissions so that it moved comfortably within the bracket of compliance.

The LJZ 72 Audi Q5 Diesel Ad Blue Vehicle was measured for VOC concentration, and showed reductions from a high of 167.1 ppm with a dirty filter down to 54.1 ppm with the primary air filter provided with a pre-filter of the invention. This was an improvement of 67.62%.

Similar reductions were found in 06 MN 1641 where high CO levels were recorded at 0.6 mg/kg with the standard filter and 0.12 mg/kg with the pre- filter of the invention.

This vehicle was within both Euro 5 and Euro 6 regulation levels prior to filter changing. However the decrease was significant.

From the above data it is clear that the pre-filter of the invention can reduce VOC, CO, NOx and possibly C0 ₂ levels of larger Vehicles where Euro 5 and Euro 6 regulations and criteria are rigidly applied specifically on the intercontinental journeys.

Example 3: Reduction of VOC level emissions in diesel and petrol engines, a diesel lorry and petrol cars.

The methodology described in Example 2 above was employed and repeated on the following vehicles:

02 CN 2431 - Suzuki GV1600 petrol;

12 LH 3457 - Peugeot 207 HDI diesel; 05 MN 2386 - Hyundai Trajet petrol;

04 MN 1535 - Toyota Hiace diesel;

11 MN 776 - Scania 13L XPI diesel Euro 4. The following generator was also tested with the invention:

L14SP - A1 diesel generator;

HF2690 - A1 diesel generator;

LDW 1603 - A1 diesel generator;

SAM 801 - A1 diesel generator.

The results achieved indicated that significant improvements upon VOC’s recorded employing the pre-filters of the invention. In particular, significant decreases of VOC’s from average highs of 801 ppm were achieved in the Generator SAM 108 to average lows of 427ppm - an improvement of 47%. In Generator LDW1603, the worst average VOC recorded was 872.5 ppm with an old dirty filter - this reduced significantly to 380.5ppm with pre-filter of the invention - an

improvement of 56%. Similar results were found across all generator tests. The VOC’s emitted from 11 MN 776 peaked at 262.7ppm with an old dirty filter installed. These figures drastically dropped to 67.2ppm with the pre-filter of the invention - an improvement of 74%. Given that this is a EURO 4 standard vehicle, it is believed that as a result of the significant improvement in VOC’s emitted that with further testing the EURO 4 standard could be also increased. Tests carried out on all vehicles showed significant improvements on VOC’s emitted.

Further data collect on fuel efficiency showed that the use of the pre-filter of the invention resulted in improvements in fuel efficiency ranging from about 4.6% to about 14.5%.

Example 4: ISO 5011 tests on Initial Restriction. Capacity and Efficiency on wrapped and unwrapped air intake filters. ISO 5011 states that filter“performance tests shall be performed on a complete air cleaner assembly or on a single air cleaner element; tests on a complete air cleaner assembly are preferred. The tests shall consist of an air flow restriction/differential pressure test, an efficiency test and a capacity test. In addition, a pressure collapse test shall be performed on the air filter element”.

Accordingly, an Initial Restriction, Capacity and Efficiency test was performed on wrapped and unwrapped filters. The initial restriction was very similar for the unwrapped and wrapped filters varying from 2.71 kN/m ² and 2.72kN/m ² for the unwrapped to 2.79kN/m ² and 2.85kN/m ² for the wrapped. This shows that wrapping the air intake filters with the pre-filter of the invention does not cause a significant pressure restriction across the filter.

The terminating condition is at a pressure of approximately 5.2kN/m ² . The

unwrapped filters reached this terminating pressure at a mass gain of 421.9 and 461.7 grams. The wrapped filters reached the terminating condition at a mass gain of 139.3 grams and 123.4 grams respectively. It should be note that in the field the pre-filter is being replaced on the original filter numerous times thus prolonging filter life. Also, the machinery vibration would seem to extend the duration of

effectiveness of the pre-filter as dust is shaken off the wrap during operation.

Example 5: Field Test

The purpose of the field test was to comparatively determine the filtration efficiency and capacity of wrapped versus unwrapped filters.

Efficiency test: The purpose of this test is to determine the comparative retention capabilities of the units under test. This test is conducted in the operating environment with the actual air flow and environmental dust conditions. Capacity test: The purpose of this test is to determine the comparative total mass gain of the unit under test at the terminating condition. The capacity determination is performed concurrently with the efficiency test.

The tests were carried out on four filters in Test site A.

The Filters are numbered and described as follows:

- Filter ID. 01 Wrapped on PowerScreen 27

- Filter ID. 02 Unwrapped on TESAB32 623C

Filter ID. 03 Wrapped on Pegasus - Filter ID. 04 Unwrapped on PowerScreen 5103

TESAB32 623C mobile rock crusher Machine working for 48 weeks (1920 Hours) requiring the air intake filter cleaned 720 times and new filters 10 minutes for each, filter site cleaning. 15 minutes for replacement of pre-filter of the invention. Washed air filters have an average two thirds life span versus new filters (“Webbsair” is an air filter wrapped with the pre- filter).

Table 2

Maintenance costs breakdown - TESAB i i 'j

■

i ■ i i

f■ ^‘ > i, ^■ i I

The savings achieved using the pre-filter of the invention per hour were dramatic. The total saving over washed filters was€16.95 per hour. The total saving over new filters was€16.91 per hour.

Komatsu Dozer A similar exercise was repeated for a Komatsu.

The total saving over washed filters was€1.14 per hour. The total saving over new filters was€1.12 per hour.

A Komatsu D85-18 track dozer working in a cement quarry required the air intake filter to be cleaned every twelve hours - the D85-18 has a monitoring device fitted in the driver cab which indicates when the air intake filter requires maintenance.

However, with the pre-filter membrane was fitted to the air filter on the Komatsu D85- 18 track dozer, no filter maintenance was required for in excess of six months despite being in use for sixty hours per week. Each filter employed in the above trials was weighed and its mass recorded as follows

- Filter ID. 01 Wrapped 1662gm Unwrapped 1627gm

- Filter ID. 02 Unwrapped 4252gm

- Filter ID. 03 Wrapped o 4429gm Unwrapped 4360gm

- Filter ID. 04 Unwrapped 672gm When the filters were cleaned (which only occurred for the unwrapped filters) they were reweighed before being reinstalled and the retained dust mass recorded. The wrapped filters were also weighed before being rewrapped. The trend was clear in that the wrapped filters retained the dust on the outer layer and dust was not penetrating into the core of the filter. There was also evidence that the vibration of the machinery was displacing dust from the surface of the wrapped filter.

As shown in Figure 10, the unwrapped filter was retaining more dust than the wrapped filter - the wrapped filter was not allowing the dust into the core of the filter and the vibration of the machinery is removing the dust cake from the wrapping. Therefore the life of the filter was being prolonged.

As shown in Figure 11 , the unwrapped filter was again retaining more dust than the wrapped filter - the wrapped filter was not allowing the dust into the core of the filter and the vibration of the machinery was removing the dust cake from the wrapping even more so than in Figure 10. Therefore the life of the filter was prolonged.