Wednesday 23 January 2013

Volvo readies engines for FH truck launch

Volvo Powertrain is making final preparations for the launch soon of the new FH series trucks. Nowhere is this more evident than in D-hall at Skõvde, where test runs are being conducted on the extended engine parts machining line.

     Volvo has invested heavily in the FH product line, and this includes an improved foundry built in 2009 at a cost of SEK 1 billion. Investment at the Skõvda facility in 2012 is believed to be between SEK 650 million and SEK 800 million.

     Skõvde is Volvo’s production biggest site; indeed it is one of the largest industrial facilities in Sweden. It effectively has three factories on one site – foundry, machining and assembly, with D-hall for machining one of the oldest buildings on the site.

     The site employs 2,900 of which 450 are employed in the foundry, 700 in machining and 700 in assembly. Assembly of the ‘long block’ is highly automated, according to sources.

      Some 10 or 12 years ago Volvo was prepared to vacate the building and turn it over to a municipal museum. But the building has since been refurbished and the machining lines extended. To the transfer lines have been added new machining centres and together they will process the cylinder heads.

     Machining centres offer the line the much needed element of flexibility; engineers will be able to make detailed modifications in head design to meet changing market conditions.

     Volvo is guarded about declaring the nature and vendor of the equipment for the head line, claiming only that ‘a number of machine tools, washing machines and assembly and test equipment’ have been installed.

     It added that ‘various known Japanese and German suppliers have been involved in the project’, although it is known ABB, one of Sweden’s largest companies, has also played its part on the Skõvde site.

     Volvo refuses to say – even approximately - how many new machine tools have been installed.

     Nor will it disclose typical cycle times for the cylinder head line. Volvo comments only: ‘Detailed capacity figures are nothing we discuss externally.’ However, sources suggest cycle times for the cylinder block line are in the region of 3 minutes.

     It is known that Volvo has expansion plans for the Skõvde facility. It has applied (and obtained) a new permit to produce 275,000 engines a year. The previous limit – though it was not reached – was 200,000 a year.

     Surprisingly, in this day and age of open communication, Volvo is equally guarded about the choice of material for cylinder heads.

     However, it is known that Volvo uses FPC or Future Process Casting in the foundry to produce the heads. This is a Volvo-branded process technology, suggesting it is patented by Volvo. It is understood the process yields a grey iron that offers tensile strengths that are ‘quite a bit higher’ than conventional grey iron, though not as high as compacted graphite iron – CGI.

     A spokesperson noted ‘this of course depends on what grade of CGI you compare (350/450) but generally (FPC) is ~ 10% higher than present green sand castings.’

     As to whether special cutting tools are used for milling and drilling FPC iron Volvo notes ‘We basically use the same tools but change the cutting speed.’

                                                               Euro 6 compliant

Volvo is no stranger to CGI though seemingly it has chosen not to use the material (favoured by Daf/Paccar, Ford, MAN, Mercedes-Benz and Navistar - but not Cummins, yet) for its engines in the new FH trucks. That will have to wait for another day.

     Volvo might argue that if it can achieve Euro 6 without CGI, why bother to use it: save it for the day when there is no alternative. As of this moment, only one Euro 6 compliant Volvo engine has been revealed; this is the 12.9-litre D13.  According to Volvo sources, no Euro 6 compliant FH16s have yet been sold.

     Another reason for not using CGI at the moment could be one of cost: Volvo’s FPC process is presumably less expensive than that required to produce high-quality CGI which demands very tight patent-controlled monitoring during the foundry process.

     And, as the new FH is cleared for Euro 6, it would appear the company can meet demanding new emissions requirements without adopting the more the expensive CGI process control technology for which Volvo would no doubt have to pay a per-component royalty fee. Just how long it can continue to meet ever tightening emission truck engine regulations without resorting to CGI however remains to be seen. Some people in the industry think it could be sooner rather than later.

      Although Volvo claimed it has used CGI as a cylinder block material for some eight years on its ‘HDE 9/11 Penta engine for some marine applications’, the company has yet to commit to the material for its mainstream truck diesel engines. Mainstream cylinder block production components use grey iron. Some Volvo gas engines also use CGI cylinder block components.

     All Volvo’s CGI components are produced in the foundry, so in-house foundry men (and there is much talk about a new foundry at some unspecified date in the future) do have experience of casting this very specialized material.

     However, the company plays down this long-term opportunity for foundry men to gain first-hand experience of CGI, claiming instead Volvo casts the material ‘mainly to fulfil product requirements’.

     As to the current cylinder heads, Volvo claims they are ‘mixed from both FPC and traditional sand casting’.

     Company sources add that Volvo has ‘had FPC for cylinder heads on HDE 9/11 and HDE 16 for some time now. FPC casting is not used for cylinder blocks.’

     According to Volvo, the weight of a cylinder head typically varies between 150-210 kg, while that of a cylinder block varies between 270-390kg depending on engine size (HDE11-16).

     Volvo produces a range of 9-, 11-, 13- and 16-litre engines. Premium-range FH trucks will carry the prestige 750bhp 16-litre unit, leaving the 13-litre to remain at the heart of more than one-third of Volvo trucks. Users of this engine do so as they are particularly mindful of the impact of fuel economy on the profitability or otherwise of their operations.

     At present, the 9-, 11-, 13 and 16-litre engines use Delphi’s unit injector-based fuelling system. But before long, Volvo will switch to the cheaper common rail system, still sourced from Delphi in Gloucester, UK. First to adopt the system will be the 13-litre engine; it will be adopted later by the 16-litre.

     It is at that stage when the flexibility of the machining centres at Skõvde will be brought into play. These machine tools will enable design and production engineers to accommodate the revised injectors. Two or three unit injectors (they are driven from the overhead camshaft) will be retained to pressurise the common rail.

     Daf has already made a similar switch from Delphi’s unit pumps (driven from the camshaft in the cylinder block) to the British company’s common rail system.

     Later, Volvo will drop the 7.2-litre Deutz engine (which also has common rail) in favour of a power unit from the former Nissan Diesel in Japan, a Volvo company since 1 February 2010 when  it was renamed Utopia Diesel Trucks.