Automotive Industry in Crisis: Traditional Design Methods Fail to Deliver Performance Improvements
Automotive Manufacturers Turn to Simulation to Meet Sustainability Targets
The pressure on automotive manufacturers to deliver more cost-effective and efficient vehicles intensifies every year. Growing concerns about global pollution have led to increasingly tighter regulations that reduce vehicle emissions and improve fuel efficiency. As a result, manufacturers are having to respond rapidly and constantly – and often there is significant variation between geographical territories.
As regulations change, the burden on vehicle and engine designers increases. Examples of these changes can be reduced weight, downsizing of engines, improved aerodynamic performance, reducing frictional losses in components and the engine as a whole. With all these changes, there is also demand for higher output. Designing vehicles with both higher output and lower weight engines is a difficult engineering challenge.
Innovation through simulation
Simulation is the key tool in meeting these challenges. From aerodynamics to acoustics, from intake to after-treatment, automotive engineers have pioneered the use of simulation in industry, producing bigger and more realistic simulations than are present in almost any other sector. Alongside finite element analysis for structural testing, an engineer might also turn to fluid dynamics to check the flow of oil, air or coolant around an engine, or combustion cycle analysis to assess the behavior of fuel.
However, even in this most progressive of industries, the way in which vehicle manufacturers use simulation software is rapidly evolving.
“Initially, we dealt mainly with stress analysis; for example, the stress on the intake/exhaust valves during operation,” says Siemens’ Fred Ross, a 30-year veteran of automotive simulation. “Computational fluid dynamics (CFD) for air flow and coolant flow was added to the mix around 20 years ago, looking at flow into the combustion chamber, plus the path of the coolant flow around the cylinders. Today, we are looking at simulating complete systems of components, including stress, thermal and flow in a single simulation. Identification of thermal stresses is very important, and simulation helps to identify where potential cracks may occur within the engine structure and guide the modification of the design accordingly. Often the worst thermal stresses occur under non-standard operating conditions, so our simulation tools need to be able to account for the full range of possible use scenarios.”
Better designs, faster
The reasons why simulation software is used have not changed, however – it saves vast amounts of time and money.
“Our customers, such as GM, Jaguar and Volkswagen,” continues Ross, “are moving towards virtual prototypes, replacing expensive physical prototypes with numerical simulation, which is advantageous both in terms of cost and in the fact that virtual prototypes can be deployed much earlier in the design process, helping OEMs to identify and correct potential problems before they occur. For example, simulation helps them to predict the performance of an engine over a wide range of operating conditions, such as driving up a hill or towing a trailer. Using simulation, they can also model the performance of the engine over a complex drive cycle, such as stop-and-go city driving."
Together, STAR-CCM+ and STAR-CD are the most widely utilized multidisciplinary simulation tools in the automotive sector, used by 14 of the 15 largest automotive OEMs.