Japanese automaker Honda is hoping to reduce the impact of its vehicles on the environment using smart design and advanced manufacturing processes. Recently, for instance, the automaker’s R&D department teamed up with software company Autodesk to redesign and 3D print a crankshaft component to make it lighter and more fuel-efficient.
In a car’s engine, the crankshaft plays a critical role, converting the oscillation of pistons into rotational force. To fulfill its function with consistency, the part must be incredibly strong and resistant to wear. For this reason and others, the crankshaft’s design has been mostly unchanged over the years, undergoing little design alterations until now.
“Crankshafts need to satisfy multiple functional criteria,” explained Hirosumi Todaka, a mechanical and fluid machinery designer at Honda R&D. “For example, its shape must be able to withstand combustion pressures, and the rotational balance must be maintained. These factors have dictated the crankshaft’s form to this day. Over the long history of engine development, the crankshaft design had become a foregone conclusion. Despite this, we set the challenging goal of designing a crankshaft to be 30% lighter than current models.”
Honda has long known the benefits of using additive manufacturing and intelligent design for optimizing automotive components. To date, the company has used the technologies to update a range of components, including seatbelt brackets, engine control units and motorcycle frames. In all these examples, Honda managed to achieve significant weight reductions.
In this most recent endeavor, Honda sought to apply similar principles it had used for these components to the crankshaft. “A new approach was required that used methods like generative design and additive manufacturing,” Todaka added. “We had to cast off preconceived notions and look at things in a new light.”
To come up with new design possibilities for the crankshaft component, Honda’s R&D team worked with Autodesk, taking into account the former’s requirements for the part and the latter’s generative design experience.
After a critical-thinking workshop, Autodesk came up with a first-lot model that met Honda’s requirements for the crankshaft using Netfabb and Fusion 360. Like many generatively designed models, the updated crankshaft had an organic structure—much unlike its conventional counterpart. According to Todaka, the 3D model was beyond his wildest imagination.
With the first-lot model showing promise, Honda sent a team to the Autodesk Technology Center in England to receive generative design training and explore AM opportunities. Importantly, the work conducted at Autodesk’s facility enabled the partners to evaluate 3D printed prototypes and fine-tune the crankshaft design even further based on new boundary conditions. Ultimately, a second-lot model was developed.
The resulting component, which was unlike anything the Honda R&D team would have come up with using traditional processes, demonstrated a weight reduction of 50%. Still, testing needed to be done to ensure that the part could perform as well as traditional crankshafts. Data collected in performance tests is now being used by Autodesk to further refine the part and its generative design process.
“While some still hold reservations about this new shape, the attention it has brought to the technology has been worth the effort,” Todaka concluded. “While there is still much that can be done to lighten parts, we can now see a way forward to reach our goals. In the future, I expect that innovative products created using generative design will be the norm. I think it is up to us to research further applications for this technology as part of our work.”