Seat sensing and heating: how integration meets performance and safety challenges

With the number of automotive comfort and safety features steadily increasing, the challenge of how to integrate multiple components into the limited space available in a vehicle’s seat, without compromising safety, comfort, design or performance, has been widely discussed. This issue has a particular impact on occupant detection and classification systems.

To date, two main approaches have emerged. The first involves moving the occupant classification sensors from the A-surface (on top of the seat foam) to the B-surface (under the seat foam). The second approach focuses on developing an integrated solution that allows the amalgamation of both occupant classification systems and seat heating.

While some OEMs have opted for the first option, there are a number of new challenges relating to design constraints, along with some questions as to its sensing effectiveness when dealing with European child seats, in particular rear-facing seats designed for six-year-olds. A capacitive occupant classification system addresses a number of these issues, but as it needs to be integrated on top of the seat heater, it influences seat heater performance.

Rising to the challenge, IEE has developed its next generation BodySense (Gen III), combining capacitive technology with seat heating, and significantly reducing the number of components for seat heating and occupant classification. BodySense Gen III offers weight-independent occupant classification that effectively disables the airbag for empty seats and children in child seats using the seat heater as a sensing antenna. Fewer components also mean less weight and, in many cases, lower costs. In combination with IEE’s PTCR-based seat heater (SafeHeat), OEMs also get the security and peace of mind that comes from the entire system being designed and manufactured by one supplier.

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