addition the cover 64 protects against external damage fig7 8 illustrate a piezoelectric regulated automotive suspension system 68 in which an auxiliary spring 80 regulated by piezoceramics operates in parallel with a conventional coil spring 72 the ground engaging wheels 69 support a chassis 70 through conventional coil springs 72 the suspension system 68 has a left and a right side and is bilaterally symmetric about an imaginary centerline each side is similar in structure and operation and similar components on the right side are indicated by prime numbers the suspension system 68 is a parallel arm type independent suspension system a bell crank arm 76 interconnects the wheel 69 and the chassis 70 the spring 72 is interposed between the chassis 70 and the bell crank arm 76 the arm 76 compresses the spring 72 when the wheel 69 moves upwardly relative to the chassis 70 a retainer arm 78 is fixed to and moves with the bell crank 76 a piezoelectric regulated spring 80 is interposed between the retainer arm 78 and the chassis 70 when the arm 76 moves to compress the main spring 72 the piezoelectric regulated spring 80 is compressed between the retainer arm 78 and the chassis 70 a similar control system 74 is provided for controlling the excitation of the spring.