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Diesel Engines Revisited. Why Should We Bother?

BY Dr Kevin Co

New to the Burnpavement.com team, contributing writer Dr Kevin Co revisits the diesel engine and tells you if diesels are the way to go.

Photos: Burnpavement.com

The diesel engine has undergone a technical revolution over the last twenty years.

In the past, diesel-powered vehicles have been considered by many to be noisy, dirty (with smelly black exhaust fumes) and underpowered.
 
Today’s diesel engines are refined, responsive and emit dramatically reduced emissions. They have retained all of the long lasting, fuel efficient, high torque qualities they have become known for, while producing less noise and vibration.

A diesel engine is actually 20-30% more efficient than a petrol engine, because more power is produced as a result of the higher compression of the air/fuel mixture. The much higher compression ratio means diesel engines have to be heavier and more robust.

This means they are more expensive to build, but the higher cost is offset by much longer lifetimes. Therefore, diesel models can cost as much as 20% more than equivalent petrol models.

Compared with petrol, emissions of the greenhouse gas, carbon dioxide, are also approximately 20% lower for diesel. In general diesel powered vehicles have significantly lower fuel consumption compared to petrol power vehicles of the same class.

In recent years, some new diesel vehicles have achieved almost similar fuel consumption as the hybrids. In Europe more than 50% of new car sold are diesel powered. So forget all your preconceptions about diesel engines - Diesel is Green.

In Singapore, the biggest obstacle is the special diesel tax, which explains why the uptake of diesel powered cars is very slow. For example, a 2.4-litre diesel car (with at least Euro 4 standards) attracts annual taxes of $4,680 compared to the $1,680 that a 2.4-litre petrol car attracts. That is quite a significant difference considering the government have already revised the tax amount in year 2008.

On the other hand, a hybrid car gets a green vehicle rebate - 40% of their Open Market Value, which is offset against the vehicle’s Additional Registration Fee. Therefore, diesel cars definitely got the short end of the stick here in Singapore. But the Singapore Budget 2012 has totally change the game.

By 2013, Green tax rebate will be replaced by the new emission based vehicle scheme. The new scheme is based on carbon efficiency and will be applicable to all new passenger cars. Car models with low carbon emissions will enjoy generous rebates on their ARF of up to $20,000, while those with high carbon emissions will have to pay a registration surcharge of up to $20,000.

And the good news for diesel is the Special Tax for Euro 5 compliant cars will be lowered from $1.25 per cc to $0.40 per cc from 2013, a reduction of 70%. This means for the same 2.4-litre diesel car the annual tax is now only $2,640, a significant $2000 difference. Looks like there is going to be a bright future ahead for diesel vehicles in Singapore after all. With the new scheme and tax revision, I have already switched over. Are you tempted?