DAF announces Euro 6 engines with common rail 11 April 2012

DAF Trucks has announced its new generation of 12.9 litre Paccar MX-13 engines, developed in response to the upcoming Euro 6 emissions legislation.

The new engine uses common rail technology, a variable geometry turbo, EGR (exhaust gas recirculation), SCR (selective catalytic reduction), an active soot filter and "advanced controls".

"The MX-13 is ultra clean [and] we've gone to great lengths to obtain industry-leading fuel efficiency, reliability and sustainability," states Ron Borsboom, member of the DAF Trucks NV Board, who is responsible for product development.

Borsboom makes the point that DAF already has vast experience with the EPA10 emissions standard in the US, noting that a quarter of Kenworth and Peterbilt trucks supplied there since summer 2010 have been equipped with the six-cylinder 12.9-litre Paccar MX engine.

"This engine complies with current North American legislation, whose emission values come close to those set out in Euro 6. We have therefore been able to build up vast experience of technologies we will now be applying in Europe for Euro 6," he explains.

"We have further developed these technologies, focussing in particular on how we can best integrate them into the European vehicle configuration," he continues. "A good example is the higher position of the EGR cooler, which allowed us to place the turbo closer to the block, further reducing the overall size of the engine."

That matters for fitting the engine in European cab-over-engine vehicle designs. It allows for a low cab floor to ensure ease of entry and maximum cab space.

"In addition, we will also be applying technologies to the Euro 6 Paccar MX-13 engine that have recently been introduced as part of our ATe programme for Euro 5," says Borsboom. "An encapsulated exhaust manifold for even better turbo efficiency and optimised piston rings and cooling are just a few examples."

Although clearly significant changes, the headlines mask further enabling developments. Borsboom says, for example, that the engine block has been redesigned for even better stiffness and, like the cylinder head, is now manufactured from strong compact graphite iron.

"With a view to ensuring maximum reliability and durability, as many functions as possible have been integrated. For example, plumbing has been cast into the cylinder block and head," he explains.

"And the two pump units that generate pressure in the common rail system have been integrated into the block, which means they can be actuated by the same camshaft that drives the valves," he continues.

"The fuel in the central pipe is supplied using smart dosing controls, to ensure optimum efficiency by only compressing the amount of fuel mixture that is really needed. This reduces hydraulic losses to a minimum."

As for the common rail system itself, injection pressures rise to 2,500 bar max, providing for pre- and post-injection, or a combination of both, as well as finer atomisation – so improving emissions noise levels and fuel consumption.

"The highly advanced engine software and new sensors and actuators also play an important role in this respect, functioning even faster and more accurately to ensure that the best possible mixture of air, exhaust gases and fuel is injected at all times," adds Borsboom.

Then, beyond the variable geometry turbocharger, EGR, SCR and soot filter (with, by the way, passive and managed active regeneration), other improvements include the single poly-V belt and fan mounted directly on the crankshaft, without a coupling shaft. The claim there is reduced maintenance, better reliability and reduced weight and fuel consumption.

Also, a larger oil sump volume allows service intervals of 150,000 km with Euro 6. That is made of composite material – again to cut weight and noise levels.

Similarly, the fuel filter and water separator have been combined into a single unit, mounted directly on the engine for ease of maintenance. And the oil cooler – which is also combined with the oil filter – is now made from stainless steel for better robustness. Cable harnesses, too, are encapsulated – as they are in DAF's current Euro 5 engines.

As for the figures, the new 12.9 litre Euro 6 Paccar MX-13 is due to enter production early in 2013, with outputs of 300kW/410bhp, 340kW/460bhp and 375kW/510bhp.

"Obviously, the introduction of new and additional Euro 6 technologies will have consequences for our vehicles," says Borsboom coyly. "We will be revealing these at the IAA in Hanover in September. You can be sure that DAF will come up with something beautiful."

Author
Brian Tinham

Related Companies
DAF Trucks Ltd

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