Simulation could make a real difference to truck efficiency

New software tools can simplify the complex powertrain optimisation strategies required to hit upcoming emissions targets. By Freddie Holmes

Powertrain development is not getting any easier for the truck industry as brands grapple with mandates to slash CO2 emissions. New electrified components and systems are required, and advanced software tools are being leveraged to better understand how they can be best put to use.

While diesel engines are generally expected to rule the roost for some time, electrification is being carefully considered by most major players. Various applications, from inner-city delivery vehicles to Class 8 semis, are in line for such an approach. It is not as simple as hooking up an electric motor, however. Each powertrain requires a painstaking process of tweaks to suit the application in question, as well as the truck maker’s own cost requirements and the needs of the end user. This cannot always be carried out in real-world tests, and computer software is being leveraged to great effect.

Electrified trucks can be seen in various use cases

“There are many influences from the market which need to be reflected in product planning: legislation, more stringent pollutant and CO2 emission regulations, competition between OEMs, end customer requirements, and even technology availability – which might not be the same across the globe,” said Gernot Hasenbichler, Product Manager Commercial Vehicle On-Road at AVL, during a recent Automotive World webinar. “New legislation will force the introduction of new technologies. The question is what are the right technologies, and what is the right combination for a specific truck brand and its applications? Powertrain optimisation will play an important role in helping to solve this conflict.”

Cameo appearance

In order to handle the complexities of a powertrain optimisation strategy, software tools are deemed vital. As with most areas of vehicle development, not all testing can be carried out physically – be it due to time or cost constraints – and simulation is filling the gap in more areas than ever.

“The more electrification or hybridisation that comes into the powertrain, the more complex the result becomes, and the harder it is to understand why something may be the optimum solution,” explained Christoph Schörghuber, Lead Engineer, System Simulation, Commercial Vehicles at AVL. “You have to limit the parameters that need to be optimised, particularly for electrified components.”

AVL has developed Cameo, a tool that can run powertrain simulations, test different approaches, and evaluate results in a short timeframe. Optimisation targets could be to improve fuel consumption by reducing friction within the engine, for example, or to increase vehicle performance by tweaking the transmission shifting strategy. Another target could simply be to reduce powertrain noise by improving the thermal management of a fan. To date, Cameo simulations have been just as accurate as real-world tests. “The results are just as good in simulations,” affirmed Hasenbichler. “You gain a very good understanding of the product.”

The pressure’s on

Cameo is not dissimilar to the Vehicle Energy Consumption Calculation Tool (VECTO), a computer simulation tool jointly developed by the European Commission and ACEA to calculate the fuel efficiency and CO2 emissions of a heavy-duty vehicle. From 2019, new EU rules require all heavy-duty CV manufacturers to register a VECTO value for common truck-trailer configurations of 4×2 and 6×2. In general, truck makers are on board with the idea; DAF and Scania, for example, have voiced support.

Truck manufacturers will be under significant pressure to continue making incremental improvements to CO2 emissions and fuel efficiency in coming years, and Hasenbichler has previously warned that simulation tools will be vital in order to ensure powertrains make the cut. Speaking to Automotive World back in October 2017, he noted that “stringent future legislation in terms of emissions and CO2 will certainly place new challenges and investment needs on OEMs.” Interestingly, he advised that AVL’s research so far has found “significant differences” between different truck brands, suggesting optimisation strategies must be tailored moving forward.

It is worth noting that the majority vote in November by Members of the European Parliament for emissions of 20% by 2025 and 30% by 2030 has not been well received across the board. The European Automobile Manufacturers’ Association (ACEA), for example, has described targets as being “far too aggressive,” with Secretary General Erik Jonnaert stating that they were “over and above the proposal made by the European Commission last May, which was already very challenging.”