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powertrain design


approach: combustion engine-electric motor-wheels;


2. Full hybrid: Early developer Toyota, noted for the Prius model, brought ‘full hybrid’ technology to the mass market. This approach is to have electric motors and combustion engine working separately or in tandem depending on speed/ acceleration needed;


THE USER CAN SIMPLY DRAG


‘BLOCKS’ FROM A LIBRARY TO DEVELOP A GRAPHICAL MODEL, WHICH CAN THEN BE SIMULATED TO SHOW SYSTEM PERFORMANCE AND ALLOW EVERY ASPECT OF THE SYSTEM TO BE INSPECTED AND ANALYSED


3. Two-mode hybrid: In this category, GM employs a two-mode hybrid such as the Chevy Tahoe Hybrid, which requires two electric motors and two transmissions besides the combustion engine. This enables the electric motors to either drive or be used as generators – or a combination of the two functions.


It is likely that the conventional engine market will continue to evolve – there’s still a long way to go before the ‘tipping point’ comes. So we continue to do a lot of work with the toolset for the development of conventional powertrains. For example, the model of the diesel engine today is based on as many as eight variables rather than the one or two that used to be the case only a few years ago.


Tony Norton, senior director for global automotive, Altair


Based in Troy, Michigan, close to America’s automotive manufacturing hub of Detroit, Altair has been producing software for 25 years for diverse product design and engineering applications.


The automotive sector represents about 50 per cent of Altair’s business, from a software and services point of view. Altair software applies to both passenger cars and heavy trucks. Today’s combination of consumer and


regulatory pressures are really compressing timelines for powertrain development. Everybody concerned is trying to achieve higher specifi c outputs as quickly and as


www.scientific-computing.com


BUSolutions, a public-private advance transit bus development initiative by Altair ProductDesign, yielded an innovative solution to the environmental and legislative challenges that confront America’s local and regional transit systems, the world’s fi rst series hydraulic hybrid bus, the LCO-140H (Low-Cost of Ownership-1st 40-foot Hybrid).


Through a ‘clean-sheet’ design approach, the extremely lightweight, heavy-duty bus design yields more than twice the fuel effi ciency of conventional buses at a lower lifetime cost. This is a fi rst for any hybrid bus. Requiring no infrastructure upgrades to operate, the LCO-140H is an attractive option for transit authorities to cost-effectively upgrade aging fl eets with hybrid vehicle technology.


The inspiration behind Altair’s BUSolutions programme initiative was driven by its global


economically as possible. Appropriate CAE technology is vital, as it cuts the need for expensive prototypes and long-term testing. The use of optimisation to take weight


out of parts and to inspire different design approaches is signifi cant for improving both powertrain and the entire vehicle’s design. The use of automation to reduce the amount of non-value-added time that engineers spend on CAE modelling to increase the throughput for a CAE department and then, in terms of the cost pressures for customers, the use of Hyperworks. Our Hyperworks ‘units’ model enables our tools to be deployed in a cost effi cient method; Altair customers buy fl exible, multi-function ‘units’ rather than have software licenses. The latest product in our suite is Simlab,


which was a recent acquisition. Working with the latter, our customers are saying they are typically experiencing a 5:1 improvement in model building speed. Simlab is feature- based, so there is feature recognition. As this package reads in a CAD fi le, it recognises key features and performs solid meshing


product development consulting organisation, Altair ProductDesign. Through an active consulting practice in the transportation industry, it became clear that the business challenges faced by owners and operators required an entirely new bus development process and design. Comprising senior management, designers, simulation experts and vehicle development engineers, Altair launched BUSolutions, an internally sponsored programme. The cross- functional team sought to apply its deep domain knowledge and a simulation-driven design methodology to fully develop a next-generation bus design. From its inception, the BUSolutions programme has continually involved industry experts from the manufacturing sector, transit authorities and passenger advocacy groups to ensure that the programme goals align with industry needs.


for features such as valve seats, bearings and crankshafts; imprints layers of elements into a solid mesh; and performs assemblies with bolts. At Altair, all software design and


development is done internally, although we work closely with our customers to develop better problem-solving packages. Altair bought CFD code Accusolve from Accusim, a company that we acquired at the end of 2010. All core algorithms are Altair developed. For the software to be able to cope with new engine designs, such as hybrids and electrics, it only needs tweaks to the Altair design and simulation modules. We consider the whole engine, whatever its type. Although Altair is not involved in combustion simulation, we are looking at other possible powertrain technologies to simulate. There are also regulatory fi gures that need to be met to achieve lower engine weights. Ultimately this will lead to powertrain downsizing. Battery weight is still a big issue for the current electric and hybrid cars.


OCTOBER/NOVEMBER 2011 43 HYBRID HYDRAULIC BUS


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