When people think of car performance, they normally think of power, torque and acceleration. But all the power generated by a piston engine is useless if the driver cannot control the car. That’s why car engineers paid attention to the suspension system almost parallel to mastering four-stroke internal combustion engines. The task of the suspension is to maximize the friction between the tires and the road surface, in order to ensure steering stability and passenger comfort.
If the roads were perfectly even, without any irregularities, the suspension would not be needed. But the roads are far from perfectly flat. Those imperfections apply force to the wheels.
According to Newton’s laws of motion, all forces have both magnitude and direction. A pothole or bump in the road causes the wheel to move up and down depending on the surface it is resting on. In any case, the vehicle has a vertical acceleration as it goes over the bumps.
Without intervention from the suspension, all the vertical energy of the wheels is transferred to the frame, which moves in the same direction. In such a situation, the wheels can completely lose contact with the surface. Then, under the force of gravity, the wheels can uncontrollably hit back on the road surface.
What is needed is a system that will absorb the energy of the vertically accelerated wheel, allowing the frame and body to move smoothly while the wheels follow the bumps in the road.
The study of the forces acting on a moving vehicle is called vehicle dynamics, and most engineers look at dynamics from two perspectives: ride – the vehicle’s ability to overcome and smooth out bumps in the road, and handling – the vehicle’s ability to safely accelerate, brake, and angle.
A car’s suspension is actually a part of the chassis, which includes all the important systems located under the vehicle’s body.