Vehicle Dynamic Suspension (G2200040): Description: Accelerometers
There are 3 accelerometers used in the Adaptive Damping (AD) system. At the front of the vehicle the accelerometer is attached to the right and left side members. At the rear of the vehicle, the accelerometer is attached to the left side member. The accelerometers are located behind the front and rear wheel arch liners.
The accelerometers measure acceleration in the vertical plane and output a corresponding analogue signal to the Chassis Control Module (CHCM). The algorithms in the CHCM calculate the heave, pitch and roll motions of the vehicle, which are used to control body motion.
Each accelerometer is connected to the CHCM via 3 wires, which supply ground, 5V supply and signal return.
The sensing element comprises a single parallel plate capacitor, a plate of which moves relative to the other dependent on the force (acceleration) applied. This causes the capacitance to change as a function of applied acceleration. This capacitance is compared with a fixed reference capacitor in a bridge circuit. The signal is processed by means of a dedicated integrated circuit to generate an output voltage that varies as a function of applied acceleration. The sensors output a signal voltage of approximately 1 V/g ± 0.05 V/g. When the vehicle is stationary, each accelerometer outputs approximately 2V.