Perfect oil separation

Press release [PDF; 25 KB]
Press release [DOC; 39 KB]



Stuttgart, September 2008–MAHLE has developed an electrically driven cone stack separator that separates oil from crankcase ventilation blow-by gas with great efficiency. The very good rate of separation is achieved by the use of a high-speed electric motor, among other things.

Combustion engines, due to their nature, have a leakage flow past the piston into the crankcase. This blow-by gas is fed back into the combustion air. First, however, it needs to be cleaned in order to meet legal exhaust gas requirements, and to prevent damage to the engine.

Currently, blow-by gas is cleaned using cyclones or impactors, i.e., passive systems. An active system, such as the cone stack separator from MAHLE, however, has many additional advantages. It consists of two independent assemblies.

In the drive unit, a brushless DC electric motor is controlled according to the engine operating map. With a variable speed of up to 10,000 rpm, the motor guarantees the correct separation rate, even for commercial vehicle engines with large displacement. For example, the cone stack separator is designed for gas volume flows of up to 200 l/min, which can be quite necessary in a 12 l diesel engine under full load. With an exclusive construction, the drive unit is hermetically closed off from the separation unit. This means that the very aggressive contaminants in blow-by gas cannot damage the drive or affect its service life.

The separation unit consists of a rotor on which conical plates are stacked in parallel. When the blow-by gas flows past the plate gaps, the oil mist is deposited on the surface of the plates by centrifugal force. Now the large oil drops can be flung further outward and separated. The cleaned gas is fed back to the combustion air.

The complete cone stack separator is attached to the engine block with a bracket, and is simple to integrate into the crankcase ventilation circuit. The robust, efficient electric drive keeps the energy required by the system low. Starting is guaranteed, even at extremely low temperatures. A 12-volt version is available for the U.S. market.

The MAHLE Group is one of the 30 largest companies in the automotive supply industry worldwide. As a leading manufacturer of components and systems for the combustion engine and related products, MAHLE ranks among the top 3 systems suppliers for piston systems, cylinder components, valve train systems, air management systems, and liquid management systems. MAHLE employs around 48,000 people at 110 production plants and eight research and development centers. In 2007, MAHLE achieved sales of over EUR 5 billion (USD 7.5 billion).


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