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Old 06-01-2013, 03:14 PM   #74 (permalink)
DLSTR
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Quote:
Originally Posted by Chuck33079 View Post
What does vvel have to do with anything regarding temperature vs viscosity loss?
Old post from the 370Z.com--- Nissan has a white paper out on the VVEL and Ester oil patent for the particles it needs to protect VVEL system.

--The white paper on the DLC explains Nissan's quest to not only use DLC on engine surfaces, but to employ it where boundary lubrication is extreme. As you might know, when the oil film breaks down from shearing or reaction between two high load surfaces, the hydrodynamic lubrication begans to diminish and contact between the surfaces occurs under boundary lubrication. This is typically when most engine wear occurs. Conrod and Main bearings rely on oil pressure to prevent this from occuring and maintain hydrodynamic function. The VVEL system has no direct means of high pressure lubrication between the drive shaft and the Rocker Arm link which encompasses the drive shaft lobe. It makes sense that Nissan would want to employ their all-carbon nano additive with this system to prevent premature wear on such a high-load surface. Even if the drive shaft were hollow to allow oil to be pumped through it to the linkage in much the same way that oil flows through the crank to the journals, this si a small surface with high pressure. Nissan's own white paper and patent both show how a DLC nano-additive could be used to protect these surfaces.

This also explains why Nissan has the default safety-mode with high oil temperatures. An oil's ability to resist shear and sustain hydrodynamic lubrication under pressure is a function of viscosity. As pressure increases on the lubrication surface, viscosity must increase to maintain a hydrodynamic function. As the oil heats up, viscosity lowers, and boundary lubrication ensues. It makes sense that nissan would be very aware of this and th detriment it could cause to the VVEL mechanism. The new, patented ester oil is a natural safe-guard.--

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