Crankcase Emissions Draw Renewed Scrutiny


CHICAGO – As heavy-duty engine builders continue to grapple with ways to cut diesel emissions, they are turning some of their attention from the tailpipe to another significant source of air pollution: the crankcase. Crankcase emissions once were vented directly to the atmosphere, but many engine manufacturers today use closed crankcase ventilation to redirect contaminants such as particulate matter, blow-by gases and oil aerosols back into the engines intake pipe assembly. Now, says Bengt Otterholm of Volvo Truck, they need added assurance that diesel engine oils are capable of controlling harmful deposits in these sensitive systems.

Speaking to a special meeting of ASTMs Heavy Duty Engine Oil Classification Panel here on March 31, Otterholm outlined a new initiative thats under way in Europe to develop a test to measure how well lubricants function under closed crankcase ventilation (CCV) conditions. As leader of the heavy-duty lubricant working group in ACEA, the trade association for European vehicle manufacturers, Otterholm explained that CCV technology will be essential to control these emissions, which will be regulated in Korea and Japan this year, the U.S. in 2007, and Europe in 2008.

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CCV systems are gaining favor because open crankcase breathers represent a substantial source of pollution from turbocharged and aftercooled diesel engines and especially those equipped with exhaust gas recirculation. Closing the breather and directing the emissions back into the combustion area, however, leads to the formation of oily deposits. As Otterholm pointed out, such deposits are the result of the interaction of temperature, oil quality and quantity, and time.

ACEA has confirmed that a need exists for a CCV-engine oil test, the first step in moving the search forward. Rather than a costly engine sequence test, though, Otterholms group expressed a strong preference for a laboratory bench test which would be reliable, cost efficient, short and as close as possible to real life with the rating criteria as turbocharger efficiency.

His working group also set a target cost of 8,000 maximum (U.S. $10,243) for any proposed test.

Otterholm told the ASTM panel that existing European tests are being evaluated, but they present significant issues. One inquiry, he added, revealed that the independent German laboratory APL already had made considerable progress in developing an acceptable test. APL has agreedto allow its test methodology to be entered into the Coordinating European Councils new test development process.This process includes a tender solicitation with open bidding – which will include APL – to select a final test developer. A final test is looked for in early 2006.

The informal process for developing this new test, under the leadership of vehicle manufacturers, contrasts with the more formal and time-consuming test development process in North America, which can take years to accomplish through the ASTM consensus process.

Otterholm concluded by saying that development of this test is widely supported in Europe. He invited U.S. test labs to participate in the planning effort, and said at least one has indicated an intention to do so.

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