Richard Russell. Globe&Mail.

Honda is an engine company that also builds vehicles to put them in.
Its very DNA is heavily laced with pistons, valves, crankshafts and blocks of metal powering everything from
weed whackers to trucks and boats.

But, far from being mired in the past and dependent on the internal combustion engine, it has embraced the future,
playing a major role in the development of hybrid power trains and most recently announcing the availability of a test
fleet of fuel cell vehicles to be leased to private owners in the United States.

So it comes as no surprise that with the growing interest in, and need for diesel engines,
Honda would go down its own road.

Let's make it clear from the outset that we are not talking about the foul, smelly, noisy diesel passenger vehicle engines
we have come to know and avoid here in North America. We are talking about what is known in the industry as the new
generation of "clean" diesels.

While the most recent generation of passenger vehicle engines, specifically those developed and offered by German car
companies, are impressively advanced in terms of vastly reduced noise and smell, they do not meet current and projected
exhaust emission standards in North America.

Addressing that problem was not possible until oil companies cleaned up their act and made low-sulphur fuel widely available.
Now that legislation has mandated they do so, automotive engineers are hard at work on a new generation of diesels that can
take advantage of the cleaner fuel to meet the tough emission standards.

Diesels, by their very nature, are about 20 per cent more fuel-efficient than a gasoline engine and more powerful per unit of
displacement. Because they have no electrical system, they require less maintenance. And because they are designed to
withstand the tremendous forces of compression ignition, they are extremely long-lived.
That combination of power, low maintenance and long life are why they are used in virtually every large commercial vehicle
in the world.

But diesels rely on compressing a fuel-air mixture until it becomes so hot it self-ignites. The resultant band that creates so
much power also makes a fair bit of noise — a lot of noise actually. Compounding the problem is the fact that diesel fuel itself
is a lower distillate — further down the refinement chain — than gasoline so that what goes into the fuel nozzle and comes out
the exhaust pipe has a pretty heady and unpleasant aroma — and results in nasty emissions.

Noise, smell and emissions, these seemingly insurmountable issues would seem to preclude further development of diesel
engines. But there is nothing an engineer likes better than a challenge.

With the reduction in the amount of sulphur in diesel fuel to less than 15 parts per million from up to 500, the first and perhaps
toughest hurdle was overcome. A new generation of diesel engines used primarily in Europe was developed around the new
low-sulphur diesel fuel.

The cleaner fuel itself resulted in vastly reduced exhaust emissions and these diesels are incredibly powerful, providing
amazing acceleration and passing abilities — far better than any gasoline engine of similar displacement.
Thanks to some trickery involving multiple injections of fuel under extremely high pressure, they are also much quieter.
As a result, diesels are ordered in about half of all passenger vehicles sold in Europe — including the top range of luxury cars.

But tighter exhaust emission standards in North America have prevented the importation and use of these "European" diesels.
Similar standards are about to come into effect in Europe as well.

As a result Audi, BMW and Volkswagen have all developed even more efficient diesels, which will find their way to our shores
in the coming months.

They all share a new system to deal with the remaining and troubling noxious emissions — they trap the problem pollutants,
inject a special urea-based solution and burn them off at extremely high temperatures, resulting in a very clean exhaust.

But Honda has developed its own system of dealing with these remaining harmful emissions and will introduce the engine to
Europe this fall and to North America beneath the hood of a 2009 Acura.

Honda says the new i-DTEC clean diesel engine reduces noxious exhaust emissions while improving both power and fuel
economy. While the competition is planning on the injection of urea, which has to be stored and replenished, in order to meet
the Tier 2 Bin5 North America and Euro5 emission standards, the Honda engine relies on a combination of optimized
combustion chamber design and reduced injection time for a clean, quiet engine without the need for on-board storage of urea.