The 10-day IAA International Commercial Vehicles Show in Hannover, Germany, is so big that some visitors bring folding bicycles so they can get around to the whole show.

One thousand, three hundred and seventy exhibitors from 40 nations. More than a quarter of a million visitors from some 120 countries. If you’re even mildly interested in the future of trucking, Hannover is where you want to be.

The first obvious sign that we were not in Kansas any more at the 2004 show: scarcely an S-cam to be found. Air discs are everywhere. And OEMs from as far away as Turkey brought their latest wares for the world to see. But the star of the Hannover show? Emission controls. Just about every truck on display sported new hardware designed to meet the Euro 4 rules that come into effect in 2006. And there’s a lesson here for North Americans.

What happens in Europe today is around the corner for our side of the pond tomorrow. Much of it, anyway. First of all, as of October 2006, the so-called Euro 4 emissions standard comes into effect across Europe. Euro 4 is roughly equivalent to the U.S. Environmental Protection Agency (EPA) standard that we’ll see over here in 2007. It will reduce the nitrous oxide (NOx) content in diesel emissions by 30 percent and particulate content by 80 percent from what is tolerated under the current legislation — Euro 3.

Nearly every heavy-duty truck manufacturer — MAN and to some extent Scania being the key exceptions — has chosen selective catalytic reduction (SCR) for meeting those standards. In 2009 the even more stringent Euro 5 standards will apply, but most European engine makers agree that SCR will work then too, with further development.

Mercedes, for one, is branding its contribution to the latter technology “BlueTec.” Beginning in mid-2005 Mercedes will offer an optional Euro-4 compliant engine — more than a year ahead of the mandatory compliance date — in its new Axor-model long-distance trucks.

The principle of SCR involves injecting an aqueous urea solution called AdBlue into the exhaust stream (metered by the engine’s electronic control), and the SCR catalytic converter converts toxic nitrous oxides into harmless products found naturally in the air, namely nitrogen and water vapor. The AdBlue solution, carried in a separate tank, is non-toxic, simple to handle and presents no problems for the driver. There’s a cost for the urea, of course, but it’s offset by fuel-economy gains — fuel consumption in SCR vehicles improves by as much as 6 per cent compared to Euro 3 models, manufacturers say.

Compare that to the opposite effect that exhaust-gas recirculation technology has had on North American diesel engines post-2002. With the Euro 4 rules, AdBlue consumption will be around 6 per cent of diesel consumption. In a long-haul truck, this represents less than 2 litres per 100 km. Given a typical urea tank capacity of 100 litres, a truck’s range with one tank of urea should be more than 5,000 km.

SCR technology has been used — and proven — for several decades in steady-state stationary engines, but it hasn’t necessarily been a slam dunk for truck diesels. Packaging issues have been huge, for instance — where do you fit the urea tank and catalytic converter? There isn’t much room along the frame rails on a European truck. Mercedes V6 and V8 engines have undergone extensive modifications, like all the others, from new materials for the block and new sealant and mounting concepts, to the reworked injection system.

DAF, Iveco, Mercedes-Benz, Renault and Volvo — representing around 80 per cent of the European truck market — have gone with SCR, and most will start selling them this coming January, ramping up the full line prior to the 2006 deadline.

Among the advantages they cite: the SCR system is virtually maintenance-free and designed for the entire life of the vehicle. It has no effect on service and oil-change intervals, there are no heat rejection issues, and of course there are fuel economy gains compared to the competing technology, cooled EGR.

German truck-builder MAN will meet Euro 4 by way of external cooled EGR with a particulate trap, and Scania will also use cooled EGR on its in-line five- and six-cylinder engines, choosing SCR for its big V8. Both truck makers are offering some Euro 4 engines right now, far in advance of the deadline, and they introduced them at the Hannover show. Common-rail fuel injection is a key in each case.

MAN says Euro 4 limits are met with a small fuel consumption gain over comparable Euro 3 engines. Other advantages: the system is maintenance-free; it needs no additional fluid and thus doesn’t depend on the AdBlue infrastructure; there are no frame-space concerns, and maximum fuel-tank capacity is retained. Also, there’s a weight advantage of up to 150 kg compared to the SCR solution.

For Euro 5, MAN is going for SCR technology, but the company warns that an adequate AdBlue infrastructure must be created.

Scania was first on the block with an engine certified for Euro 4, a cooled-EGR 420-hp model with compound turbochargers and high-pressure fuel injection (Scania HPI) in production as of September. Euro 4 emission levels are met without any aftertreatment –emissions are tackled at source, inside the combustion chamber –with no adverse effect on fuel economy, the company says. For its full range of inline engines set for fall 2005, Scania will continue with EGR and high-pressure fuel injection. It’s a different story with the company’s V8 diesels. To ensure adequate cooling capacity, they’ll get SCR to achieve Euro 4.

From 2006, Scania will offer three Euro 5 engines based on SCR technology, one output in each of its 5-, 6- and 8-cylinder ranges. The full range of Euro 5 engines will hit market well ahead of 2009.

There are compelling incentives for delivering Euro 4 and Euro 5 engines ahead of the deadline. In Germany, for example, a toll system for commercial vehicles covering all roads will be launched in January, but trucks meeting Euro 4 standards will get a break — they’ll pay 10 instead of 12 Euro cents per kilometre. In the Netherlands, more favorable depreciation rates will be the reward.

Similar incentives to use environmentally friendly technology are expected in other European countries as well.

Like we said, there’s a lesson in there for North America.

Rolf Lockwood is editor emeritus of Today's Trucking and a regular contributor to

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