Technical sessions focused on interiors at the SAE 2014 World Congress span the designated technology areas, including electronics, materials, and safety/testing. One example in the electronics area, to take place April 8 at 9:30 a.m., covers Multi-Media Systems.

Takata researchers will present their paper (2014-01-0266) titled “In-vehicle Touchscreen Concepts Revisited: Approaches and Possibilities” as part of the multi-media discussion. The authors review current technologies such as capacitive touchscreens and resistive touchscreens, noting that they both have certain drawbacks—for example, in their distraction potential and their usability.

As an alternative, the Takata researchers focus on the generation of a holistic touch experience: auditory, visual, and haptic feedbacks combined with accurate force sensing for activation and deactivation. Using this approach, two new independent technologies were identified that, when combined, offer a powerful alternative to the current systems with a much greater focus on usability and haptic responsiveness.

The use of force sensing is an essential component to the system. Therefore, the first key technology to this system is the use of a very new and unique, accurate, responsive, repeatable, durable, and linear sensing system, with unperceivable displacement that does not suffer with the inherent issues of flexible printed elastomeric solutions, such as creep, unwanted environmental effects, etc.

The second key part to the system is the use of a fast-acting haptic system that can generate a significant tactile haptic response. In this instance, the technology can also generate an audible component that can be tuned to give direct audio feedback.

By using a static overlay material, a digital button can be recreated, with digitally tunable audible effects, tactile haptic effects, and switching thresholds. This presents new opportunities, such as conventional button replacement or implementation of controls where none was possible before.

By replacing the static overlay with a digital screen overlay, the same system can be applied to create a unique and compelling touchscreen system, without affecting the screen readability, contrast, or visibility.

Such a force-based digital system opens up several potential application areas for further implementation that were compromised, costly, or technically challenged using existing technologies, according to the Takata researchers. Such a system could allow for multi-state force-based switching with dynamic tactile haptic and audible feedback, while reducing the packaging challenge on the steering wheel design. When combined with passive haptic designs, it is possible that a natural evolution of the current interfaces is possible—one that is more in line for future vehicle systems.

With sufficient thought and planning, they concluded, a new holistic interface incorporating the steering wheel displays, digital center console, and digital instrument cluster can be achieved, not only enhancing the user experience but also allowing the vehicle to continue to evolve toward a semi-autonomous future while minimizing driver distraction.

As part of a materials session at SAE 2014 on Advances in Instrument Panels, Seats, and Interiors, scheduled for April 8 at 1:00 p.m., Chrysler and Chrysler India Automotive researchers will present their work (2014-01-1025) on “Strength/Stiffness Simulation Techniques and Test Correlations in Automotive Interior Cockpit Systems.”

The development of a cockpit system requires a lot of simulation work to verify its performance prior to prototyping, the authors note. They explain the various CAE methods and techniques used to simulate the virtual stiffness test for the floor console, door trim, and instrument panel (IP) assemblies. They also present the correlation of the CAE results and the lab results, which could reduce product-development time and cost at an early stage, before the prototype is made and physically tested.

What the researchers found is that the CAE tools can be used efficiently to predict the stiffness of the cockpit systems, but they also observed some deviations in a few stiffness test values toward the CAE predictions. Some major areas identified that need more attention to improve the accuracy of the CAE results include: modeling techniques of components and joint representations (fasteners, track, hinge, snaps, welds, etc.); nonlinear material models used for engineering plastics, rubber, and foam parts; the conversion of the physical test setup to the CAE setups like loading applications, constraints, etc.; usage of CAE methods like implicit and explicit solvers, and their benefits and limitations; and types of contact used to avoid penetrations, and load transfers between the surfaces.

Other papers in this session will focus on advanced materials for interior applications. Renewable, bio-based fillers consisting of coconut shell and torrefied wood are explored for use in an HVAC case application by Hyundai-Kia America Technical Center researchers (2014-01-1026). And JSP and Toyo Seat engineers present their findings on a polyurethane-free lightweight seat that features expanded polypropylene (EPP) padding and reportedly results in a 30-50% weight reduction (2014-01-1033).

Human Factors in Seating Comfort is an interiors-focused Safety/Testing technical session scheduled for April 8 at 9:30 a.m. Researchers from Hyundai-Kia America Technical Center and Hyundai Motor Group feature prominently in this session, presenting a combined four technical papers. One of these is “Seat Comfort of Thin Foam Seat Cushions of Varying Densities and Thicknesses” (2014-01-0453), by Michelle Pereny of Lear Corp. and Scott Ziolek of the Hyundai-Kia tech center.

Seat assemblies in vehicles present the biggest opportunity for weight reduction among the various other in-cabin components, the authors note. Reducing foam thickness is seemingly an easy way to reduce weight of the seat system; however, making the foam thinner without understanding the impact to the seat system and comfort could be problematic.

For their examination, the researchers selected a Hyundai Sonata seat frame. Three production-level seat frames were modified to support the cushion foam pads that were about 20 mm (0.79 in) thinner than those in the current production Sonata; no changes were required in the back structure. The modified foam pads were poured using the same chemical formulation (foam index) but at different density levels.

They concluded that opportunities exist to reduce foam thickness for the Sonata; however, changes to the seat structure and cushion suspension must be investigated for a successful implementation. The next phase of their study will evaluate dynamic performance of the seats through damping and vibration transmissibility objective testing and a long-term ride-and-drive evaluation.

Other organizations represented in the Seating Comfort session include Toyota Technical Center USA, Fiat SpA, Wuhan University of Technology, and the Korea Research Institute of Standards and Science.