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Diesel Tech Leaders Urge Caution Against Raising Biodiesel Blend

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Diesel Tech Leaders Urge Caution Against Raising Biodiesel Blend

Leading manufacturers of diesel engines are urging caution against any move by the government to promote biodiesel blends beyond B7 grade. Of late, there have been calls from palm oil industry lobby groups urging the government to mandate B10 and B20 biodiesel programmes, likely as a response to falling prices of crude palm oil.

Presently, all diesel fuels sold in Peninsular Malaysia are B5 biodiesels, which contains 5 percent blend of palm oil derived fatty acid methyl esther (FAME). The government is reportedly constructing 15 biodiesel blending facilities in Sabah and Sarawak and the target is to rollout B5 biodiesel nationwide by early 2015.

As long as the percentage of FAME content is kept at 5 percent or less, biodiesels will not cause any damage to diesel engines.

However when news reports of the Malaysian Biodiesel Association urging the government to implement B10 and B20 biodiesel programmes began to surface in February, it raised some concerns within the automotive industry.

BMW Group Malaysia, which sells the diesel-powered BMW 520d, one of the most sophisticated luxury sedans on the market, has confirmed that running conventional diesel engines with B10 biodiesel will cause serious damage to the engine.

Extensive testing by BMW has shown that using B10 biodiesel will result in formation of oil sludge (image below), deposits in the fuel injectors, corrosion of components, oxidation in the fuel tank and blocked fuel filter.

In a reply to, BMW explained that the fatty acid methyl esther (FAME) content in biodiesel boils at high temperatures and gets into the engine oil, which then results in the thinning of motor oil. This in turn leads to oil sludge, reduced lubricity with the risk of severe engine damage.

BMW also found B10 biodiesel leave behind a formation of film on the injectors. This results in invariance of injection, as well as reduced stability of idling cycle, unstable emissions and changed engine acoustics.

Using biodiesels also result in higher levels of water in fuel, which then leads to corrosion of components in the fuel system and oxidation in the fuel tank, which leads to a blocked fuel filter.

BMW also cautioned owners from fueling their cars with B10 biodiesel, as today's BMW engines are enabled to run up to B7 biodiesel only and using B10 blends will void the vehicle's warranty.

The company also disagrees with the overly simplistic notion that increasing palm oil content in diesel is a step towards cleaner exhaust emissions.

"Is biodiesel a cleaner technology? Yes. But only if the fuel specifications are better where the levels of sulphur are low. Then we are able to see the true benefits of a clean fuel," said Sashi Ambi, Head of Corporate Communications at BMW Group Malaysia.

BMW is not alone in this. The Japan Automobile Manufacturers Association (JAMA) also concurs with BMW's findings.

JAMA cited results from a study conducted by the Japan Auto-Oil Programme (JATOP) on the impact of B10 biodiesel blends on diesel engines - "...the double bonds chemical compound found in unsaturated fats of all FAME feedstocks, which leads to poor oxidation stability and easier low temperature solidification, is the key that contributes to the difference (in quality) between FAME and conventional diesel."

JATOP's findings are similar to BMW's - the engines tested all had problems of corrosion in the fuel system, oil sludge, lacquer in fuel injectors, fuel filter plugging, engine oil dilution and degradation, as well as foreign matter adhering on the suction control valve after long parking periods, which in-turn led to idling trouble.

JAMA also added that other than specially modified diesel engines, diesel engine vehicles for the past century have been designed and developed to be used with conventional diesel fuel.

Isuzu is one of the world's largest manufacturers of diesel engines and it too is cautioning against promoting biodiesel blends higher than B7.

When asked about the compatibility of B10 biodiesel with Isuzu engines sold in Malaysia, Isuzu Malaysia said:

"One of the primary concerns about biodiesels of grades B7 and above has been, among others, the high presence of water in the blends of Palm Methyl Ester. Biodiesel is hydroscopic in nature and tends to absorb water from the atmosphere. This can cause deposit formation, microbial growth and degradation of fuel quality. These phenomena can affect the vehicle's engine operation and durability.  

"In view of this, Isuzu, as one of the world's largest producer of diesel engines, collaborates with the Japan Automobile Manufacturer's Association (JAMA) that based on test findings, the current acceptable limits of water content in biodiesel is only acceptable to grade B7 only. Further conclusive tests will need to be conducted and proven to be consistent in result to allow for any levels from B7 onwards."

Mercedes-Benz Malaysia, which sells the locally-assembled diesel-electric E300 BlueTec Hybrid, the first diesel-electric hybrid vehicle in Malaysia, also confirms that it can use B7 biodiesel but only if it meets the European Union's EN590 standard. Its engines can also run on B100 biodiesel but only if the fuel meets the EN14214 standard.

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