The need for miniaturization and improved packaging has led Continental to claim a world first for the integration into a single component of the yaw rate and acceleration sensors for ESC (electronic stability control) systems.
Announcing the development, the company stated that a major challenge had been the prevention of unwanted frequencies and signal cross-talk between sensors—solved via the use of silicon sensors. Continental added that it had successfully achieved a higher level of resistance to resonance and vibration and at ambient temperatures of up to 125°C (257°F).
"With this development, Continental is remaining true to its philosophy of making safety systems such as ESC available to all motorists," said Dr. Ralf Schnupp, Continental’s Head of Inertial Sensors, Chassis & Safety Division. "Compact design, a higher level of resistance to vibration and temperature, and lower costs are helping us to achieve this goal. At the same time, the complete integration in silicon technology is offering us the option of making highly developed assistance systems such as ACC (adaptive cruise control) or active front steering even more effective through the use of high-precision sensors."
The new cluster is entering series production and is scheduled to be used in MY2010 vehicles.
Acceleration and yaw rate sensors are central to providing ESC with the necessary information about the vehicle's condition. The system’s measurements include the rotational speed of the wheels, the car's lateral and longitudinal acceleration, steering movements, and yaw ratio. It correlates the acquired data to accurately calculate in which direction the vehicle is traveling and the driver is steering.
To date, micromechanical sensors have been used specifically for the acceleration sensor, says Continental, but now purely capacitive sensors made exclusively from silicon were being used for yaw rate and acceleration sensing. The company regards them as being more cost-effective and offering higher resolution with increased sensitivity to measurement. The new systems also ensured only "very slight" deviations in measurement accuracy and, most importantly, only slight deviations in measurement readings over a long service life.
The compact design of the sensor cluster saves space, makes it easier to fit, is more cost-effective, and enables the use of ESC in models "of all vehicle categories." Through the integration of the combined yaw rate and acceleration sensor in ESC or airbag control units, reliability in safety-critical applications would be increased still further as fewer external components needed to be used and linked together.
As well as the standard application for ESC, use of the new sensor cluster also meets with high-precision specifications to further improve the performance of already well-developed systems including ACC (providing improved radar accuracy), active front steering, and intelligent headlamp control. It would also increase the accuracy of fault monitoring on redundant systems.
The highly integrated signal processing has been designed to monitor and analyze all internal signals, covering all levels of the signal chain. If the system detects a fault, it is saved in a separate, nonvolatile memory and can be read using diagnostic equipment, thus expanding the range of diagnostic options, both for the sensors themselves and for the sensor cluster as a whole, further enhancing overall product quality.