Electronically controlling lubricant filtration

Dr. Neil Canter, Contributing Editor | TLT Tech Beat January 2010

This purification system enabled a fleet owner to extend operating intervals for trucks to 120,000 miles between oil changes. 

KEY CONCEPTS
• A lubricant purification system that removes both solids and liquids has now been upgraded through electronic monitoring.
• This new system now constantly evaluates the condition of the lubricant and automatically adjusts the filtration and evaporation processing to maximize contaminant removal.
• Customers see a return on investment in less than a year with minimal maintenance.

The continued tightening of heavy-duty diesel emissions has placed more maintenance pressure on fleet operators. Current EPA emissions standards in 2010 for particulate matter are now 0.01 grams per hp hour. Nox emissions cannot exceed 0. 2 grams per hp hour.

Sulfur content of diesel fuel has been reduced from 500 ppm to 15 ppm. The latter is considered Ultra-Low Sulfur Diesel and will be required for all on-highway vehicles in December 2010.

Filtration is an important part of the process of maintaining automotive lubricants so they can perform at the levels required to provide good performance and minimize emissions. In a previous TLT article, a new type of filter based on nanofiber technology was discussed (1). This filter provided an upgrade in efficiency due to its ability to operate on both the macroscopic and microscopic levels.

But solids are only a portion of the contaminants found in automotive lubricants. Liquid contaminants also are present, which means that an additional approach is needed to remove them as well.

A dual approach to removing contaminants can lead to a more efficient procedure for extending the operating life of the automotive lubricant. Optimization of this process through electronic control has not been available until now.

ENHANCED FLUID PURIFICATION
Oil Purification Systems, Inc. (OPS), in Shelton, Conn., produces a unique technology that removes both solids and liquids from lubricants. Bill Priest, OPS’ vice president of engineering, says, “Our approach is to remove solids and then liquids in a purification system that is maintained onboard the vehicle and used during its operation. The purification system is installed in a bypass configuration so as not to interfere with the engine filter.”

The company has just developed a new product called Eco-Pur™ that electronically monitors the condition of the lubricant and automatically adjusts the filtration and evaporation processing to maximize contaminant removal. The new system is based on technology developed with the company’s OPS-1 product and is an evolution of that system.

Priest says, “Our new approach utilizes state-of-the-art electronics to monitor and control performance, providing optimal efficiency regardless of environmental conditions. This product can be used in many more applications.”

The first step is to remove solid contaminants through filtration. Priest explains, “A proprietary microglass media is used to remove solids from lubricants. Our reinforced, pleated filters are designed to utilize the mechanisms of interception, sieving and bridging. This enables contaminants to be captured and retained over extended periods of time with minimal restriction in flow across the media.”

The filter has an efficiency of 94% in removing particles that are 3 microns in size and larger. Priest adds, “The filtration enables the 5- to 10-micron particles that are most likely to inflict wear on the engine to be removed.”

In the second step, the lubricant is moved into an evaporation unit to remove liquid contaminants. Priest says, “Our patented process for removing liquid contaminants from fluids includes a number of factors required for efficient evaporation. The technique starts in an evaporation chamber that utilizes laminar flow of the filtered effluent over a uniquely designed metal chamber known as a platen. The platen is heated to provide sufficient energy to the fluid to facilitate vaporization of the contaminants.” 

Priest continues, “Once the vaporization is achieved, a pressure differential created in the evaporation chamber due to the temperature difference with ambient conditions creates sufficient flow to remove any vapor generated during the cleaning process.”

Priest indicates that the main contaminant removed in this fashion is water. No foreign component is added to the lubricant at this stage. The impact to the components and lubricant basestock is minimal. Priest says, “The emissions from our system have been tested by accredited testing facilities and found to be innocuous. There is also no direct impact on the lubricant basestocks or additives used.”

Priest maintains that the evaporation process subjects the fluid to much less energy than is found in the engine. He adds, “We have seen this from the thousands of samples analyzed with a myriad of lubricants.”

The evaporation process does not contribute additional detrimental emissions that could cause a commercial vehicle to violate current EPA regulations. Priest also indicates that the purification system is compatible with all lubricant basestocks, including synthetics such as polyalphaolefins, esters, polyalkylene glycols and phosphate esters.

The purification unit is very compact in size and only weighs 5 lbs. Priest cites this feature as a major benefit. He says, “Our approach is not dissimilar to that used in commercial dehydration systems with the primary difference being expediency. Lubricant flow through the unit is low, but we make up for this factor by being more efficient in terms of mass and volume.”

Most of the applications for the purification unit have been in automotive heavy-duty diesel engines. Priest says, “Our technology has expanded to gear lubricants, hydraulic fluids, transmission fluids and even waste vegetable oil.”

This purification system has enabled fleet owners to extend operating intervals leading to reduced costs and emissions levels. In one case, a fleet owner extended the operating interval for its trucks to 120,000 miles between oil changes, leading to a 60% reduction in costs.

In general Priest estimates that customers see a return on investment in less than a year. Maintenance of the purification unit is minimal and involves just filter changes. Samples of the lubricant are pulled periodically and analyzed to ensure that contaminant levels are minimized.

This new product installed in a commercial engine is shown in Figure 2. Additional information about the filtration and evaporation purification process can be found in a recent patent (2) or by visiting www.ops-1.com. 


Figure 2. A new technology installed onboard a vehicle has been developed that electronically monitors the condition of the lubricant and automatically adjusts processing to maximize contaminant removal. (Courtesy of Oil Purification Systems, Inc.)

REFERENCES
1. Canter, N. (2006), “Nanofiber-Based Oil Filters for Diesel Engines,” TLT, 62 (6), pp. 19-21.
2. Whitmore, C., Gutierrez, J. and Gutierrez, J. (2007), “Method of and System for Fluid Purification,” U.S. Patent 7,244,353 B2.

Neil Canter heads his own consulting company, Chemical Solutions, in Willow Grove, Pa. Ideas for Tech Beat items can be sent to him at neilcanter@comcast.net.