21st June 2017 by Richard Yen
Our next look back at the 2016 Altair Enlighten Award concerns a nomination from drive train and brake system specialists, FTE in Germany. The entry focused on the company’s lightweighting efforts for its new EP20 oil pump, engineered to operate in a transmission dry-sump lubrication systems.
The majority of transmissions utilize a “splash lubrication method” which provides the required lubrication to all the gear sets. Those transmissions have an oil pan that is always filled with oil. The gears dip into the oil and transport the lubricating fluid (more or less) uncontrolled to the various areas of the transmission thus insuring the lubrication. Turning gears in oil generates friction though which negatively impacts the overall transmission efficiency. A dry-sump lubrication system insures that the gears do not dip into the oil, since the sump is as the name suggests – dry. It requires a pump, which pumps the lubricating fluid out of the oil pan into a fluid distribution tank located on top of the transmission. From there the oil flows due to gravity to the various areas of the transmission, insuring the lubrication.
Such dry sump lubrication systems have existed for a number of years and utilize positive displacement pumps (mostly G-rotor pumps) driven mechanically or with a brushed electric motor. In contrary FTE’s new EP20 features an inexpensive, highly integrated, lightweight centrifugal pump driven by a small and simple 1 phase BLDC claw pole motor, which can be switched on & off on demand and which provides real time diagnostics through its integrated LIN controller to the TCU.
Traditionally, the centrifugal pump of such a system would be constructed from metals due to the extreme heat generated inside the oil pump. In an effort to save weight, FTE’s EP20 features a kinematic type pump which is almost entirely made from engineered plastic materials, which is highly unusual considering the application.
The team at FTE successfully reduced weight by around 50% over a positive displacement oil pump driven by a larger motor. So far transmission oil pumps did always utilize positive displacement pumps. The fact that FTE choose a kinematic type pump instead of a more traditional positive displacement pump, opened new opportunities in regards to the material choice, complexity and motor design.
In addition to weight savings, the production cost of the EP20 is estimated to be roughly 60% lower than the cost of a standard positive displacement transmission pump driven by a larger BLDC motor. FTE’s nomination was a great example of an innovative new design for a component enabling the use of light materials which in turn enables manufacturers to lower costs along with weight.