How big an engine do you need in a class 8 heavy truck operating in North America? Engine market share figures for 2010 indicate that truckers’ performance expectations are rising, with a swept volume of 15 litres or more, able to deliver at least 500hp, becoming ever more in demand. Sales statistics show that Cummins‘ 15-litre ISX diesel, well established but now extensively re-engineered with common-rail fuelling and SCR NOx control, remains a popular choice, in ratings up to 550hp. However, for the customers of truck market-leader Freightliner, availability of parent Daimler‘s in-house up-to-560hp DD15 and up-to-600hp DD16 power units is eroding Cummins’ dominance.
Confirming the trend is the loss of market share suffered by Navistar since it dropped the ISX option after Cummins executed a U-turn in its emission control strategy, through the proprietary engine supplier’s adoption of urea-fed SCR (selective catalytic reduction) NOx control. It ran counter to Navistar’s loudly trumpeted aversion to SCR, which chimed with the ‘non SCR’ technology of its own MAN-based MaxxForce in-house diesels. The largest MaxxForce engine currently offered displaces a relatively modest 12.4 litres, delivering 475hp at its highest rating.
How big an engine do you need in a class 8 heavy truck operating in North America? Engine market share figures for 2010 indicate that truckers’ performance expectations are rising, with a swept volume of 15 litres or more, able to deliver at least 500hp, becoming ever more in demand.
Meanwhile Paccar continues to offer the Cummins ISX, but is increasingly trying to persuade its Kenworth and Peterbilt end-users to specify instead the group’s newly-available in-house MX engine, presently being shipped in from DAF in the Netherlands, until it goes into full production at Paccar’s new – and first ever – North American engine plant, in Columbus, Mississippi. But in addition to being a largely unknown quantity to deeply conservative US transport operators, especially owner-drivers, the MX engine, like Navistar’s MaxxForce 13, falls short on capacity compared with the familiar, outsourced, ISX. Its displacement is 12.9 litres with ratings up to a maximum 485hp.
Volvo and its sister brand Mack, while continuing to list the 15-litre Cummins diesel, are better placed than Navistar and Paccar to offer power-hungry buyers comparable performance to the ISX, in the shape of the Swedish group’s own in-house 16.1-litre D16 engine, developing up-to-535hp. Take-up of the D16 in Volvo/Mack chassis has to date been limited, with the price premium over the mainstream Volvo 12.8-litre D13 engine as something of a marketing obstacle.
Paccar continues to offer the Cummins ISX, but is increasingly trying to persuade its Kenworth and Peterbilt end-users to specify instead the group’s newly-available in-house MX engine
Some market analysts have suggested that the increasing pre-eminence of 15-litre-plus engines in the North American class 8 market has been concentrated on the long-haul segment, especially among operators running coast-to-coast at the federal maximum allowable combination weight of 80,000lb (36.3 tonnes), having regularly to negotiate tough gradients when crossing the Rocky Mountains.
But against the background that heavy trucks in North America have much longer working lives than their European equivalents – typically ten or 12 rather than six or seven years – it is also likely that today’s buyers are anticipating a country-wide increase in permitted weights. Already several states, probably with an eye on European practice, have mooted higher truck weights within their boundaries, with 88,000lb (say 40 tonnes) and 96,000lb (say 44 tonnes) as likely gross weight limits for introduction in the next year or two.
The opinions expressed here are those of the author and do not necessarily reflect the positions of Automotive World Ltd.
