Oaf reveals new MX-11 engine By David Wilcox DAF HAS
Page 11
If you've noticed an error in this article please click here to report it so we can fix it.
joined Mercedes-Benz, Volvo, Renault, MAN and Iveco in raising the profile of 10.5to 11-litre engines for Euro-6 tractor units. Daf's new 10.8-litre engine, unveiled last week, replaces its 9.2-litre PR engine at Euro-6 and is expected to be the number one choice in CF tractors and multiwheelers.
As forecast by CM last November, the six-cylinder Paccar MX-11 engine slots in beneath the 12.9-litre MX-13, covering nominal power ratings from 290hp to 440hp. But it isn't a downsized MX-13: this is a substantially new design and is more advanced.
Whereas the Euro-6 MX-13 retains the current MX's sidemounted camshaft and push-rod operated valves the MX-11 has double overhead camshafts, so there is no commonality in the block or head. Bore and stroke dimensions are different too. The MX-11 also has a short third camshaft mounted low on the side of the engine, with just two cams to drive the two fuel pumps pressurising the Delphi common-rail fuel system. This arrangement keeps the upper portion of the engine slim to reduce the width of the engine tunnel, and allows Daf to use the same fuel injection system as on the MX-13.
Engine management control system and exhaust after-treatment are also the same. MX-11 uses the same balance of EGR and SCR as the Euro-6 MX-13, so AdBlue consumption is expected to be 3%-4% of fuel consumption. A Holset VGT (variable geometry turbine) turbocharger helps to manage EGR and improves transient response. There is an optional engine decompression brake too, sourced from Jacobs.
Daf is so confident about its new engine it forecasts the MX-11 will be fitted in 80% of CF tractors and multiwheelers — and even in 20%-25% of XF tractors too, where only the 440hp MX-11 will be offered as an alternative to the MX-13.
Its key attractions will be fuel consumption — up to 3% better than a Euro-6 MX-13, claims Daf — and a weight-saving of 180kg against the MX-13.
The latter offsets the additional weight of Euro-6 emissions kit, making MX-11 attractive for weight-conscious tippers and tankers. The downside is a shorter B10 design life; 12 million km for the MX-11 compared with 1.6 million km for the MX-13.
Daf applies a haulage label to the top two MX-11 ratings, each with a fairly typical peak torque plateau spread of 1,000Nm1,450Nm. The other three are described as distribution ratings, with wider torque plateaus from 1,000rpm to 1,650rpm. This improves engine flexibility, reducing gear-shifting on distribution work with fluctuating road speeds.The intriguing choice facing operators is the small area of overlap between MX-11 and MX-13. Do they choose a 440hp MX-11 with 2,100Nm, or a 410hp MX-13 with 2,000Nm? Their prices will be on a par.
The first UK MX-11 engines are due in CF and XF 4x2 tractors arriving in September, followed by 6x2 units and then multiwheelers within the next couple of months. There will be an MX-11 in the 4x2 CF tractor on Daf's CV Show stand next month.