With the increasing pressure to reduce emissions, friction reduction is always an up-to-date\ntopic in the automotive industry. Among the various possibilities to reduce mechanical friction,\nthe usage of a low-viscosity lubricant in the engine is one of the most effective and most economic\noptions. Therefore, lubricants of continuously lower viscosity are being developed and offered on\nthe market that promise to reduce engine friction while avoiding deleterious mixed lubrication and\nwear. In this work, a 1.6 L downsized Diesel engine is used on a highly accurate engine friction\ntest-rig to determine the potential for friction reduction using low viscosity lubricants under realistic\noperating conditions including high engine loads. In particular, two hydrocarbon-based lubricants,\n0W30 and 0W20, are investigated as well as a novel experimental lubricant, which is based on a\npolyalkylene glycol base stock. Total engine friction is measured for all three lubricants, which\nshow a general 5% advantage for the 0W20 in comparison to the 0W30 lubricant. The polyalkylene\nglycol-based lubricant, however, shows strongly reduced friction losses, which are about 25% smaller\nthan for the 0W20 lubricant. As the 0W20 and the polyalkylene glycol-based lubricant have the same\nHTHS-viscosity , the findings contradict the common understanding that the HTHS-viscosity is the\ndominant driver related to the friction losses.
Loading....