The executive summary of the latest report from North American market research company R. L. Polk, looking at the choice of engines offered to heavy-duty truck buyers in the US and Canada, highlights what appears at first to be a straight option between 13-litre and 15-litre diesels. Reference to engine make and horsepower are dealt with as almost secondary issues.
Polk reports that 40,935 new class 8 trucks with 13-litre engines were registered in the first half of 2011, as against 35,427 with bigger 15-litre power units. The figures reverse their relative positions in 2010, when whole-year registrations were 49,511 units at 15 litres and 32,220 at 13 litres. The analysts point out that the larger of the two diesel sizes had in fact been ‘more popular’ than the smaller alternative ever since 2002.
Volvo’s mainstream heavy-duty engine is a 13-litre unit, which also powers long-haul models from its subsidiary Mack.
A more meaningful trend which Polk could perhaps have headlined in its report is the swing away from engine outsourcing towards vertical integration by all the North American heavy truck manufacturers. A decade ago there were almost no indigenous ’13 litre’ engines in the market, apart from Detroit‘s 12.7-litre Series 60 unit. Market leader at that time was Cummins, but it had a yawning gap in its range between the (now discontinued) 10.8-litre ISM and the 15-litre ISX. Caterpillar had its C13, though it was offered only by Paccar.
Polk’s focus on the 13-litre versus 15-litre battle highlights the extent to which the OEMs with European connections (now all of them) have succeeded in substituting their own ‘newly acquired’ in-house diesels for the engines previously bought in from, most notably, Cummins. Caterpillar is no longer a competitor, and today’s Detroit engines are German designs listed only by Daimler sister companies, primarily Freightliner.
Volvo‘s mainstream heavy-duty engine is a 13-litre unit, which also powers long-haul models from its subsidiary Mack. The Swedish OEM also has a 16-litre engine, though it has not been vigorously promoted, probably because of its high cost. Navistar, through its engine joint-venture with MAN, can offer nothing larger than 12.4 litres – which it nevertheless calls its MaxxForce 13, produced in Huntsville, Alabama. Paccar, meanwhile, is pushing its in-house DAF-engineered MX 13 litre diesel now being assembled in Columbus, Mississippi.
Paccar is pushing its in-house DAF-engineered MX 13 litre diesel now being assembled in Columbus, Mississippi.
Daimler’s Freightliner and Western Star brands are in the happy position of being able to supply either 13 or 15-litre diesels from its own new-generation range of in-house engines. Daimler nevertheless, in common with Paccar and Volvo/Mack – but not Navistar – continues to offer Cummins’ 15-litre ISX, typically specified by customers through long-standing brand loyalty or even American patriotism.
Some observers have speculated that Cummins might try to enlarge its new smaller 11.9-litre ISX unit by a litre or so, in order to grab a share of that seemingly more popular 13-litre market segment. At present it largely rules the roost at 15 litres, especially for buyers wanting 550hp performance or more.
The opinions expressed here are those of the author and do not necessarily reflect the positions of Automotive World Ltd.
Alan Bunting has a background in engineering, and has been writing on commercial vehicle and powertrain related topics since the 1960s. He has been an Automotive World contributor since 1996.
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