Traton subsidiary MAN is to phase in a new generation of trucks before 2021 – with the first stage of the process comprising changes to its engine line-up, to coincide with the introduction of the Euro 6-D emissions standard this summer.
Crucially, forthcoming changes to European construction regulations will allow the introduction of new truck cabs with more rounded aerodynamic fronts in 2020.
Euro 6-D places greater emphasis on emissions conformity during engine warm-up and in low-load conditions. MAN launched the first new engine of the Euro 6-D lineup at the CV Show earlier this year: the nine-litre D1556 (Transport Operator 81).
The best-selling D26 engine, currently available at three ratings ranging from 420 to 500 hp, gets a 10 bhp boost in each version, taking the 12.4-litre engine through the 500 hp barrier to 510 hp.
There is a new single-stage wastegated turbo, a more robust crankshaft and bearings, a new EGR module, and new pistons and injection-timing sequences.
Ratings for the larger 15.2-litre D36 engine were booted at Euro 6-C, and remain unchanged at 540 to 640 hp, but the engine has been modified to allow oil-change intervals to be extended by 40 per cent, and approval is pending to allow the use of fuel-saving 0W-20 oil with low friction piston rings and cylinder liners.
All engines get an ‘intelligent’ three-phase alternator, which monitors battery state. When the engine is under load, it only generates sufficient power to balance the current electrical load. When the vehicle is in over-run, alternator output is increased to top-up the batteries. Not only does this reduce parasitic drag, it also extends battery life by reducing over-charging.
Parasitic drag is further reduced by a new single-cylinder air-compressor. Lighter than the twin-pot unit that it replaces, it features an expansion chamber in place of the second cylinder. When the truck’s air tanks are sufficiently charged, a third valve in the compressor head vents compressed air into the expansion chamber. Much of this pressure is then used to drive the compressor piston on its downward stroke, reducing parasitic drag without the complication of clutching the compressor in and out of use when required.
Fuel filter modules share common components across all engine ranges from D08 to D38, and the D15 and D26 engines have a controllable coolant pump. There is now a modular external exhaust gas aftertreatment system, with just two basic silencer variants.
Thermal management has been optimised on all engines to ensure sufficient exhaust temperature is quickly enough during warm-up to conform to Euro 6-D.