microGreenTM Extended Performance Oil Filter: An Innovative Hybrid Spin-on Oil Filter Assembly for Reduction in Lubricant Consumption

N. Assion*, M. Flamenbaum** and D. Sahoo***

*SOMS Technologies, LLC, 4 Broadway, Suite 11, Valhalla, New York, 10595 USA, norbert@somstech.com

**SOMS Technologies, miles@somstech.com ***SOMS Technologies, debashis@somstech.com

ABSTRACT

The microGreen filter is a hybrid assembly of the

conventional full flow filter cartridge and a microfilter. This assembly can be fitted to an internal combustion engine exactly like a conventional spin-on filter but results in the motor oil being in serviceable condition even after 30,000 miles of driving. The particle count in the oil as well as the engine wear parameters remain low and the oil viscosity is relatively unchanged. The oil film quality remains similar to unused oil. The result is an extended performance spin-on filter system with benefits observed in maintenance cost, engine life and environment.

Keywords: hybrid-filter, spin-on, extended-performance, lubricant, conservation.

1 INTRODUCTION A conventional motor oil filter is designed to

continuously remove particulates from the oil. Conventional filters are based only on a single full-flow filter element through which all of the oil must pass through before reaching the engine. This design means that a conventional filter cannot achieve high-efficiency in order to keep the oil pressure low and maintain adequate oil flow, thus leaving smaller particulates in the oil. Without continuous removal of all particulates the oil gradually loses its ability to lubricate the moving parts of internal combustion engines and hydraulic pumps. Therefore, in the case of vehicles, the oil needs to be replaced, along with the oil filter, every 3,000 to 5,000 miles of travel.

The microGreen filter consists of a conventional full-flow filter cartridge and an additional microfilter; both contained within one standard spin-on filter housing (see Fig. 1). The microfilter component removes particulates down to 2 microns in size without affecting oil pressure. This significant improvement in efficiency ensures that lubricating oil cleanliness can be maintained for extended use of the oil.

The microGreen filter is available in an array of sizes and configurations and is being commercially sold by SOMS Technologies, Valhalla, New York. On-road tests supported by independent oil analyses indicate that vehicles fitted with the microGreen filter are able to operate up to

30,000 miles without an engine oil change. Oil monitoring was conducted by taking oil samples from vehicles after approximately every 3,000 - 5,000 miles of travel.

Figure 1: Section of the microGreen filter illustrating the hybrid assembly of two filtration units (the microfilter and the conventional filter media). The assembly also contains the other essential functional units such as the anti-drain back valve, the pressure relief valve, a high quality canister and a steel base plate with standard thread to fit into the engine.

2 LUBRICANT OIL PARAMETERS

The following oil parameters are presented from these

tests: 1. Particle count: An assessment of the number of 5

micron sized particulates in 1 ml of oil using ISO 4406:1999. It indicates cleanliness level of the oil.

2. Total Acid Number (TAN): Measured using ASTM D664, TAN is the quantity of base, expressed in milligrams of potassium hydroxide that is required to neutralize 1 gram of oil. TAN indicates acidity level of the oil.

3. Iron: Measured using ASTM D5185, iron is introduced into oil through wear and tear of cylinders, liners, pistons, rings, valves, valve guides, anti-friction bearings, gear train, accessory

High quality canister

Pressure relief valve

Steel base plate and standard thread Anti-drain back

valve

Conventional filter media

Patented microfilter system

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gear drives, shafts, clutch plates and rust. Iron, expressed in ppm, thus indicates wear level in the engine moving parts.

4. Viscosity: Measured using ASTM D445, viscosity is reported in centistokes at 100 degrees C. Viscosity measures the oil’s resistance to flow. Thinning may come from excessive fuel dilution or the addition of lighter (less viscous) oils. Thickening generally represents higher total solids or addition of heavier (more viscous) oils. Viscosity variation thus indicates degradation in motor oil lubrication quality.

These measurements were made partly in WearCheck USA, Cary, North Carolina and partly in Herguth Laboratories, Vallejo, California.

Figure 2: Motor oil cleanliness evolution during on-road testing using the microGreen filter.

3 TRENDS IN OIL PARAMETERS

Assessment of these parameters enables the

understanding of whether the oil remaining in the engine is suitable for further service and that the lubrication properties remain at nominal levels. The scope of this paper

is limited to describing the trend in the evolution of each oil parameter over vehicle mileage as an indication that the increased filtration efficiency provided by the filter can extend the use of the lubricating oil.

The evolutionary trend in the oil parameters was calculated as follows. Linear regression estimation of every parameter was first made across the different distances for a given vehicle. Then a linear average of those estimates across the different vehicles at a pre-specified mileage value was computed to produce the trend. The data was collected from more than 50 vehicles running more than 500,000 test miles. 3.1 Particle Count

Fig. 2 illustrates the trend for particle count. The new oil cleanliness level was calculated by taking an average of all 5 micron particle counts across the oil samples. Many of the initial samples were with used oil. The microGreen filter quickly cleaned the used oil and, as illustrated in Fig. 2, the filter maintained the oil cleanliness beyond 3,000 miles to at least 30,000 miles.

Figure 3: Motor oil Total Acid Number (TAN) evolution during on-road testing using the microGreen filter.

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microGreen filter installed without an oil change.Oil mileage represents mileage driven using the filter

with no oil change.

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Oil mileage represents mileage driven using one or more microGreen filters with no oil change.

Filter replaced approx every 25K miles.

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3.2 Total Acid Number (TAN)

Fig. 3 shows the progression of the oil TAN with mileage. It is clear that the acidity level has an increasing trend with mileage. This behavior is similar to that seen in extended mileage studies conducted using by-pass filters in large trucks and buses [1, 2]. The reason for the increase in TAN merits further study and is currently under investigation. The decreasing portion of the TAN graph after about 20,000 miles could be considered to be an artifact of the statistical averaging technique employed as well as relatively less number of vehicles tested above 20,000 miles than below.

3.3 Iron

Figure 4: Evolution of iron concentration in motor oil during on-road testing using the microGreen filter. The normal, abnormal, and severe levels are given above the

graphs [3].

Fig. 4 exhibits the trend in iron concentration in the oil with increase in mileage. It is clear that the concentration of

iron in the oil remains much lower than the abnormal level. This seems to indicate that the engine components did not reach a critical level of wear even after at least 30,000 miles of travel. The increasing portion of the graph after about 25,000 miles could be considered to be an artifact of the statistical averaging technique employed as well as relatively less number of vehicles tested above 25,000 miles than below. Although the trend seems to increase after 25,000 miles, it is well below the abnormal limit.

3.4 Viscosity

Figure 5: Evolution of motor oil viscosity during on-

road testing using the microGreen filter. Fig. 5 shows how the oil viscosity varies with mileage.

It is clear that the oil viscosity is virtually unchanged even after at least 30,000 miles of driving. The kink in the graph after about 25,000 miles could be considered to be an artifact of the statistical averaging technique employed as well as the aggregate number of vehicles tested at various mileage intervals.

35 ppm (Normal) _.100 ppm (Abnormal) .200 ppm (Severe) .

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microGreen filter installed without an oil change.Oil mileage represents mileage driven using the filter

with no oil change.

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Oil mileage represents mileage driven using one or more microGreen filters with no oil change.

Filter replaced approx every 25K miles.

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microGreen filter installed without an oil change.Oil mileage represents mileage driven using the filter

with no oil change.

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Oil Mileage

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Oil mileage represents mileage driven using one or more microGreen filters with no oil change.

Filter replaced approx every 25K miles.

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3.5 Oil Film Quality

Fig. 6 shows the test fixture used to measure the oil film quality. The test fixture confirms to the ASTM G99-95a standards and consists of a rotating steel disc partially immersed in the test sample with its surface being scratched by a steel pin. The results obtained were the coefficient of friction derived from the force transducer reading, and the disc scar width. The disc scar width represents simulated wear of engine parts in contact with each other and separated by the test oil film.

Figure 6: Pin-On-Disc Test fixture to measure oil film

quality. Testing was performed in Herguth Laboratories, Vallejo, California.

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microGreenFiltered, 25K

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FrictionWear, mm

Figure 7: Pin-On-Disc test results. Figure 7 shows the pin-on-disc test results on three

types of oil. The first one was “new” or unused oil obtained by thoroughly mixing new oil from several brands. The second sample was taken from a vehicle driven around 10,000 miles without concurrent oil change and fitted with a conventional motor oil filter. The third is an average taken from two vehicles driven for 25,000 miles without oil change and fitted with microGreen filters. The coefficient of frictions of all three oil samples is similar even though the mileage on the vehicles with the microGreen filter was 25,000. More interestingly, the wear as represented by the disc scar width was less than that corresponding to the conventional filtered oil and was even better than new oil. This demonstrates that the oil film quality corresponding to microGreen filtered oil is at least as good, if not better, than new oil in the test vehicles.

4 CONCLUSION A hybrid assembly of the conventional full flow filter

cartridge and a microfilter (which removes smaller particles) results in the following qualities in engine lubricating motor oil:

(i) The oil remains clean to at least 30,000 miles of driving the engine even without any concurrent oil or filter change.

(ii) The acidity level of the oil tends to increase slightly with mileage although it remains at or near nominal levels. The reason for the increase is under current investigation.

(iii) The engine components do not reach a critical level of wear.

(iv) The viscosity level of oil is virtually unchanged. (v) The oil film quality remains as good as unused oil

even after extensive use. In spite of slight increase in acidity, the oil is still in

serviceable condition even after 30,000 miles. These qualities lead to the conclusion that the microGreen filter, which this hybrid assembly is called, is an effective extended performance filtration solution for lubricating motor oil used in internal combustion engines. Usage of this hybrid filtration system will lead to more than 70% reduction in oil use over the engine life. This has the added benefits of substantial reduction in oil maintenance costs; reduction in filter consumption; improved engine life and vehicle maintenance; and is also beneficial to the environment.

REFERENCES [1] SAE 2000-01-0234. [2] SAE 2001-01-1898. [3] Source: Gasoline Engine Oil, Herguth Laboratories,

Vallejo, California: http://www.herguth.com/fluid/ gasoline_engine_oil.htm.

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