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DIESEL ENGINES European Union (EU) requirements are broadly similar in approach to those in the U.S. market, with Stages I and II introduced between 1999 and 2004, then Stages IIIA and IIIB becoming mandatory for new engines during 2006-2008 and 2011–2012, respectively. The final EU requirement, Stage IV, comes into play next year for off-highway engines with an output above 56 kW. Tognum group specialist engine supplier MTU told E&MJ; that from January 2015, off-highway engines with rated outputs more than 560 kW will be subject to Tier 4f emissions standards of 3.5 g/kWh for NOx, 0.19 g/kWh for hydrocarbons, 3.5 g/kWh for carbon monoxide and 0.04 g/kWh for PM. However, Volvo Penta pointed out there is a paradox in relation to achieving these reductions. Focusing on reductions in NOx results in increased PM, while lowering PM levels will result in higher NOx concentrations in the exhaust. Different engine manufacturers have followed different routes to achieve the goal. Some (like Volvo Penta) have opted exclusively for selective catalytic reduction and exhaust gas recirculation as their main abatement mechanism, while others have preferred to use diesel particulate filter technology as well, to ensure a catch-all solution. Caterpillar: Wider Range of Rebuild Kits Aside from powering its own products, Caterpillar is a major supplier of industrial engines to other equipment manufacturers. The company reported it is now offering a new generation of Tier 4f/Stage IV engines from 25.2 to 895 kW (34– 1,200 hp) that give good fuel efficiency and component life, with significantly reduced emissions. Units on display at bauma included the C1.5, C7.1 ACERT and C18 ACERT engines, as well as the C4.4 ACERT, C13 ACERT and C7.1 ACERT power units. Cat equips every Stage IV/Tier 4f engine with a combination of electronic, fuel, air, and after-treatment components based on engine size, the type of application, and the geographic location in which it will work. The technologies offered include a diesel oxidation catalyst (DOC), diesel particulate filter (DPF) and selective catalytic reduction (SCR), with a "No DPF" after-treatment package available for some applications. "As we designed our Stage IV/Tier 4 Final engines, we did so with the end in mind in order to make integration as simwww.e-mj.com Bronze kit, plus the cylinder packs, a cylinder head, fuel injectors or fuel nozzles, a water pump and an oil pump. The types of equipment covered by these kits include motor graders, excavators, mid-range tracked dozers, wheel dozers, wheel loaders and articulated trucks. Liebherr: In-house Systems Design Cat C7.1. (Photo courtesy of Caterpillar) ple as possible for our OEM customers," said Mike Reinhart, Caterpillar industrial marketing manager. "We've been able to meet emission legislative standards while delivering value to our customers. As a result, we have the strongest, most complete product range available for customers and manufacturers looking for a robust, fuel efficient industrial engine solution." The larger engines on display were the C13 and C18 ACERT units. The C13 is a six-cylinder, 12.5-liter engine that delivers 287–388 kW (385–520 bhp) and is used in a wide variety of applications such as crushing, drilling, materials handling and pumps. Meanwhile, the C18 industrial engine is a six-cylinder, 18.1-liter unit that is similarly sized to its Stage IIIB/Tier 4i predecessor, with twin DOCs fitted to the 563–597 kW (755–800 bhp) ratings to comply with Tier 4f emission standards, Cat said. In April, Cat also announced an extension to the availability of its Precious Metals engine-rebuild kits for some of its machines. Available in four levels (Bronze, Silver, Gold and Platinum), the kits are now available for C9-powered equipment as well as machines powered by 3406, 3306 and 3176 engines. Bronze kits provide basic components such as gaskets, seals, oil and fuel filters, camshaft bearings, exhaust manifold sleeves, etc. Silver kits include the Bronze kit, plus new, unassembled pistons, piston rings, retainers and cylinder liners, while Gold kits include the Bronze kit and six Cat Reman (remanufactured) pre-assembled cylinder packs. Platinum kits include the Since 1985, Liebherr has produced diesel engines for use in its own machines as well as to supply other equipment manufacturers. Its extensive stand at bauma showcased some of its current 11-model basic range, which offer power outputs from 130 to 750 kW (174–1,005 hp). All of its fourand six-cylinder in-line engines, as well as its V8 and V12 units, comply with the Stage IV/Tier 4f emission regulations, the company said. Liebherr explained that in order to meet the new criteria, it has intensively optimized the complete combustion process with the aim of minimizing the level of particulates generated inside the engine. One of the major factors in coordinating the various parameters involved has been the inhouse development of a common-rail fuel injection system, together with a Liebherrdesigned electronic engine management control unit. To keep the system simple and optimize exhaust emission control in even the toughest operating conditions, Liebherr decided to concentrate on SCR technology. This has economic benefits for the customer and also simplifies machinery design, the company said. Since particulate emissions are already below the statutory limits, no measures are needed to reduce them further. The SCR catalytic converter, and its associated system components reduce NOx emissions by around 98%, Liebherr added. Focusing on reducing particulates formed inside the engine, Liebherr has "X-ray" view of Liebherr's Tier 4f-compliant engine design. (Photo courtesy of Liebherr) JULY 2013 • E&MJ; 47