greater degree of integration simplifies the E/E architecture, prevents the need for a separate sensor cluster while retaining the same housing dimensions, and reduces system costs. “Improving safety is becoming a noticeably significant feature of the Chinese market, leading to demands for enhanced airbag functions together with a requirement for ESC functionality. What we are seeing here is the beginning of a possible trend towards integrating the vehicle dynamics sensors into the airbag control unit,” said Dr. Ralf Schnupp, head of the Occupant Safety & Inertial Sensors (OSIS) branch in the Passive Safety & Sensorics Business Unit of Continental's Chassis & Safety Division.
Sensor integration for growing safety requirements
At present, ESC control units often receive their vehicle dynamics data from a separate sensor cluster equipped with an interface for supplying the ESC and the airbag control unit with the vehicle's longitudinal and lateral acceleration and the yaw rate about its vertical axis. In contrast, the 3D sensor cluster, based on micro mechanical silicon sensors, is already integrated into the SPEED S safety control unit. “Consequently, the introduction of the SPEED S variant provides more options for processing the vehicle dynamics data in algorithms,” explained Joachim Schäfer, head of the OSIS customer center. He offered the following example of a potential enhancement: “If the vehicle gets into a skid, experience frequently shows that a side impact will follow. An expanded database will allow restraint systems such as belt tensioners and airbags to be activated with greater accuracy, so as to achieve the most effective occupant protection in any particular accident situation.”
SPEED XS control unit in use in China since mid-2012
Thanks to the SPEED unit's modular design, the airbag control unit is becoming a comprehensive safety domain controller. Launched on the global market in 2009, its five variants – from XS and S to M, L and XL – have been developed to fit the requirements for different levels of active and passive safety complexity. The requirements and economic conditions of different markets and applications are met by scalable hardware modules (ASICs, micro-controllers) and scalable software and mechanics (housings) modules. The SPEED platform forms part of ContiGuard®, Continental's comprehensive function and network concept for active and passive safety.
The basic variant (SPEED XS) includes activation of the restraint systems in the event of front and side impacts. Continental has been producing this SPEED XS airbag control unit in China since mid-2012. 2014 should see the first SPEED S safety control units with integrated driving dynamics sensor being produced in China itself. “We set up local teams in this important market some years ago and we intend to expand our presence here,” said Dr. Schnupp, “because we reckon that, in the long or short run, China will introduce more far-reaching statutory provisions in relation to vehicle safety equipment and, in particular, to the use of ESC.”
The larger SPEED variants (M, L and XL) can include not just vehicle dynamics sensors, but a rollover sensor, a crash impact sound sensor and interfaces to numerous external sensors (camera, radar, lidar). This means that in premium vehicles with high-performance environmental sensors the role played by the SPEED control unit can be expanded to that of a comprehensive safety domain controller, i.e. a central control unit for coordinating safety functions. ContiGuard® functions, such as PreCrash or Post Crash Braking, include assessing critical driving situations and activating the appropriate braking function or reversible restraint system.