Vehicle oil filters are vital to long engine life, especially if changed on schedule or after exposure to severe conditions. Now vehicle OEMs and owners of cars, trucks, and off-highway machinery have a new weapon in fighting engine and powertrain wear thanks to Ledu Quoc Nguyen, senior development engineer at Purolator ArvinMeritor.
While it is easy to think that an oil filter is providing protection against particulates that can cause wear, Nguyen notes that metal particles less than 12 microns can still pass through filter material into an engine or transmission. Some vehicles may have a magnetized drain plug to capture metal particles, but unless the oil comes near the plug, these will not be removed.
Nguyen's patented filter design incorporates a magnetic material within an oil filter to trap metal particles when all the oil is continuously pumped through the filter. The configuration also keeps metal particles out of the filter's paper elements, prolonging their effectiveness. The metallic particles are trapped as oil flows radially inward through a plastic plug threaded into the end of the filter (see diagram). A ferromagnetic material impregnated in the plastic below a set of radial vanes, which direct the oil to the filter core, has circumferential pockets that collect the metal bits attracted by the magnetism. If needed, the plug can be removed from the engine or transmission filter for cleaning without rechanging the filter.
Stronger than dirt: As oil passes over them, scalloped pockets at the edge of the ferromagnetic and plastic layer (purple) of the oil-filter end cap trap metal particles, which can pass through the paper elements of an oil filter.
Nguyen says the biggest challenge in bringing about the filter was finding the right material that could be one-shot injection molded to form the metal-particle trap. The result is a 3:1 ratio of ferromagnetic material particles to a proprietary high temperature plastic. This mix is molded and then magnetized, because pre-magnetized particles would tend to clump together. Once the material was selected, the size and shape of the pockets that trap the metal particles was optimized for effectiveness using I-deas CAD software from EDS.
For the next step in product development, Nguyen will inset-mold a magnetic field sensor into the end cap. This will send a signal to the driver or operator when the energy loss in the magnetic field is sufficient to indicate the plug needs cleaning. So there will be no excuse for not changing oil when needed.