3 3 F O C U S Photo: AVL because by 2020, an extensive natural gas fueling infrastructure for long-haul trucks is to be put in place. In my opinion, alongside diesel fuel, natural gas will be the second key fuel for long-haul trucking,” Lukas Walter, Vice President, Commercial Powertrain Systems On-Road & Engines, said. Further drivers for the increased use of natural gas as fuel for commercial vehicles are the ever-increasing efforts to curb carbon emissions all over the world. In natural gas powered vehicles, carbon dioxide emissions are reduced by as much as 25 percent, depending on the application. The use of natural gas for fueling heavy-duty vehicles will be crucial for Europe to reach the CO2 emission targets after 2020. EFFICIENCY AND DURABILITY To make gaseous-fueled engines an attractive alternative to diesel-powered engines, top priority has to be given to optimizing efficiency and range. “The natural-gas engine in commercial vehicles will remain a converted diesel-powered engine for a considerable number of years. AVL is extremely successful in converting such engines and complete systems and is able to contribute its vast amount of expertise and many years of experience in engine development. After all, AVL did help to develop a large number of these engines from scratch,” Lukas Walter said. Due to the higher combustion temperature inside the gaseous-fueled engine, it is absolutely critical, when converting a diesel-powered engine, to ensure thermal durability. The adjustments needed are diverse and range from developing the cooling concept for the overall system, new materials for valves and valve-seat rings and the pairing of piston ring and the cylinder liner to adapting the material for the exhaust manifold to suit the higher temperature levels of the exhaust emissions. “The increased thermal stress, in particular, necessitates changes to the design of several components. AVL is able to implement patented solutions in this respect. These have to be applied and tested, but mainly to ensure their durability. To accomplish these tasks, we draw on our extensive experience and know-how in the field of validation planning and apply the well-known AVL ‘Load Matrix’ principle. By a special choice of test methods, it becomes possible to shorten the time factor in testing very substantially. This allows us to efficiently make statements on the durability of specific components,” the specialist for HD vehicle drives pointed out. STOICHIOMETRIC COMBUSTION PRODUCES OPTIMUM EFFICIENCY In addition to the advancements in combustion concepts for gaseous-fueled engines, such as the lean-burn combustion system, dual fuel and HPDI (high-pressure direct injection), AVL is focusing its efforts on stoichiometric combustion in order to comply with the tight emissions legislations. This particular combustion concept has the advantage of satisfying the exhaust emission limits by employing a relatively affordable 3-way catalytic converter. The other concepts require rather more costly exhaust gas aftertreatment systems,” Lukas Walter explained. Another advantage of the naturalgas engine is the lower peak pressure level during combustion. Here, at AVL, the possibilities are being explored to incorporate such evolving requirements into the development of specific – and particularly costefficient – gaseous-fueled engines. Crucial to the development of an efficient natural-gas engine is smart software control – yet another of AVL’s strengths.” AVL harnesses its vast knowledge and expertise in engine design and combustion development in conjunction with its software know-how to develop a natural gas engine which is just as highperforming and efficient as a modern diesel-powered engine,” Lukas Walter added. These new naturalgas engine technologies, developed by AVL, some of which are currently undergoing the patent application process, will in future contribute significantly toward lowering air pollution from trucks. COMPREHENSIVE EXPERTISE AND STATE-OF-THE-ART TOOLS The perfect blend of extensive engine design expertise and advanced tools and methods makes AVL the ideal development partner for gaseous fueled engines in HD applications. Lukas Walter: “Over recent years, we at AVL have made some major investments to broaden our know-how in the field of gaseous-fueled engines. Today, at AVL’s technical centers in Europe and North America, which place a special focus on natural gas, we combine the comprehensive indepth knowledge of our engineers with the most advanced simulation and testing methods, enabling us to support our customers all over the world in the development and conversion of engines for natural-gaspowered operation.“ <
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