The future of road transport

How simulation is powering innovation

By Luke Morris

Modern transportation has changed the world. By drastically cutting journey times countries, continents, and indeed the whole globe have become much smaller. People and goods can travel further and faster, opening up new economic possibilities for everyone.

But the adoption of the internal combustion engine as the preferred method of powering transport for the best part of a century has come at a significant cost. Of the 50 billion tonnes of CO2 emitted globally each year, 8 billion comes from transport alone. Road passenger and freight vehicles account for around 75% of this figure.

Switching to electric propulsion is an obvious way to significantly reduce this impact. According to the latest Mobility Consumer Index, more than 50% planning to buy a car will choose either a fully electric, plug-in hybrid, or hybrid vehicle.

Something must change, and fast. If emission reduction targets are to be met and a climate catastrophe avoided, the automotive industry must accelerate the transition from internal combustion propulsion to electric propulsion. As Bill Gates recently said, “We need to be adopting electric vehicles as fast as we bought clothes dryers and colour TVs when those became available.”

This is far easier said than done, however. Manufacturers need to produce vehicles that customers want and offer them at a competitive price. For a company like General Motors (GM) which has over 100 years of experience with brands such as Chevrolet, Buick, GMC, and Cadillac, a new approach to development is needed to produce the environmentally friendly and economically viable vehicles of the future.

Of course, it’s not possible to make an immediate and complete switch to producing electric vehicles. GM needs to follow a carefully planned transition, which means developing internal combustion engines, hybrid drive units, and electric drive units at the same time.

This means an increased number of complicated, separate development threads. Finding ways to reduce the cost of each thread and speed up development time is critical to a successful transition and the continued profitability of the company.

Michael J Grimmer is Technical Fellow in the Propulsion System Global Noise and Vibration department at GM. He explained how his team has adopted simulation to meet these challenges, facilitate innovation, and help the company stay ahead in an increasingly competitive market.

Driving quality forward

Whichever type of vehicle is being developed, driveline quality is key to performance, comfort, and fuel economy. To optimise it, engineers need to fully understand the energy efficiency on the drive quality and seat acceleration experienced by the driver and passengers.

Building physical prototypes to carry out these tests is an expensive and time-consuming process. To overcome this, GM has used Simcenter Amesim to build comprehensive digital twins of each vehicle they develop. This allows them to perform many more what-if analyses than previously, so that when they do build a physical prototype it is much closer to the ideal solution.

Grimmer cites driveline noise and vibration reduction as an example. Previously, they had to design and build prototypes of components such as isolators and perform physical tests to understand their impact. This would typically take several months and cost up to $50,000. With Simcenter Amesim, GM engineers can create these isolators virtually using model-based systems engineering (MBSE) techniques and carry out the testing in the simulation environment. All in a matter of days at a significantly reduced cost.

Encouraging innovation

Simulation has also delivered a huge boost to innovation for GM. When physical prototypes are needed to prove concepts, risk must be minimized to avoid wasting critical development time and money. Engineering experience, best practice, and analysing results from existing similar products can only do so much, and this limits the opportunity for innovation.

By introducing simulation, engineers can experiment with their designs and test many more concepts in a much-reduced timeframe. Grimmer says, “We can do concept selection based on simulation of how products will perform. This greatly expedites the number of options we can consider and the correctness of the ones that we choose.”

Ultimately, accurate simulation is enabling innovations in vehicle design that would never previously have the chance to be fully explored and realised.

Improved methodology

With the adoption of Simcenter, GM has established new simulation-based standard work practices that improve their overall development processes. In the case of driveline noise and vibration, this means better optimisation and balance of all elements. They have used simulation to establish best practices that also take into account the energy and fuel economy requirements of each vehicle. The capability to simulate so many different designs and scenarios allows engineers to develop solutions that achieve the optimum balance across these different performance areas that previously wasn’t possible.

The Simcenter portfolio also enables better cooperation between teams and suppliers as models can be easily shared, as Grimmer explains:

“The Simcenter Amesim models that we build are easy to operate by others and can be integrated into the rest of the system and with the controls. Another user from a different engineering team can receive the subsystem model from us or even from a supplier as a black box and integrate it in their workflows quite effectively.”

Technology that evolves with the industry

As vehicle technology, and electric technology in particular, continues to evolve at a rapid pace, simulation must evolve too to keep up and maintain its usefulness. To ensure the software is always at the cutting edge of simulation, Simcenter Engineering and Consulting services work closely with companies such as GM to understand the challenges they face and inform the future direction of products like Simcenter Amesim.

Grimmer says his GM engineers will work with the product development team on new or improved features that will enhance their experience and add functionality.

“Modelling torsional isolators within the trans-mission involve arc springs that have unique physics and Simcenter Amesim has an out-of-the-box sub model for modelling those physics, which was improved to achieve much quicker and accurate simulation,” he says. “Another example is what’s called a viscoelastic spring and its interface was improved for a more intuitive version based on our needs. That was extraordinary product support. We’re very pleased with the product support we get with Simcenter Amesim.”

Transition of practices as well as products

Physical testing is still a crucial component of the overall development process to ensure optimum quality in new vehicles. But clearly the more testing that can be replaced with simulation, the better, cheaper, and faster development will be.

To advance this transition, GM exports simulation data from Simcenter Amesim into Simcenter Testlab to compare simulation results directly with test data. This enables validation of their virtual models and gives increased confidence in using more simulation in the future.

Grimmer firmly believes that simulation accelerates product performance prediction, allowing teams to make well-informed decisions in earlier development stages. As simulation improves it’s becoming possible to not only model and simulate a broader range of product designs, but also production, manufacturing variation, and what-if analyses.

So, the key to reducing road transport’s impact on the environment is not one transition but two. For GM and other manufacturers to carry out a successful transition to more environmentally friendly vehicles and stay competitive they need the support of a technology transition: the introduction and increase of the use of simulation to enhance their development processes, foster innovation, and reduce costs and time to market.