Electric vehicles (EVs) are becoming more popular than ever, thanks to their environmental benefits, lower maintenance costs, and tax incentives. However, EVs also have unique challenges affecting their performance and driving experience. One of these challenges is the suspension system, which plays a vital role in ensuring a smooth and comfortable ride.

What is Suspension, and Why is it Important?

Suspension is the system of springs, shock absorbers, and linkages that connect the wheels to the vehicle body. It has two main functions: to support the weight of the vehicle and to absorb the impact of road irregularities, such as bumps, potholes, and curves.

A good EV suspension system can improve a vehicle's handling, stability, and safety. It can also reduce the noise, vibration, and harshness (NVH) that drivers and passengers feel inside the cabin. NVH is especially important for EVs, which are much quieter than conventional vehicles with internal combustion engines (ICEs). Without the engine noise to mask the road noise, EVs need to have a better suspension system to minimize the NVH levels.

How is EV Suspension Different from ICE Suspension?

Electric vehicles have some distinctive features that make their suspension system different from ICE vehicles. These include:

• Weight distribution: EVs tend to have a lower center of gravity and a more balanced weight distribution than ICE vehicles. This is because EVs have battery packs that are usually mounted on the floor or under the seats. This reduces the body roll and improves the cornering ability of EVs. However, it also increases the unsprung mass, which is the portion of the vehicle’s mass that is not supported by the suspension. A higher unsprung mass can reduce the responsiveness and comfort of the suspension system.
• Regenerative braking: EVs use regenerative braking to recover some of the kinetic energy that would otherwise be wasted as heat. Regenerative braking reduces the need for mechanical braking and extends the battery life of EVs. However, changing the load transfer and braking torque distribution between the front and rear wheels also affects the suspension system. This can cause uneven tire wear and reduced traction.
• Drive mode: EVs can have different drive modes, such as eco, sport, or comfort, that alter the performance and efficiency of the vehicle. These modes can also affect the suspension system by changing the stiffness, damping, or height of the springs and shock absorbers. For example, sport mode can make the suspension firmer and lower to enhance the handling and aerodynamics of the vehicle. Comfort mode can make the suspension softer and higher to improve the ride quality and clearance of the vehicle.

What are Some Emerging Technologies for EV Suspension?

To address these challenges and optimize the performance and comfort of EVs, several technologies have been developed or are being researched for EV suspension systems. Some of these are:

• Active suspension: Active suspension is a type of suspension system that can adjust its parameters in real-time according to road conditions, vehicle speed, and driver input. Active suspension can use sensors, actuators, controllers, and algorithms to independently control each wheel's force or displacement. This can improve EVs' handling, stability, comfort, and NVH by reducing body roll, pitch, yaw, bounce, and vibration.
• Regenerative suspension: Regenerative suspension is a type of suspension system that can harvest some of the energy that is normally dissipated by the shock absorbers as heat. Regenerative suspension can use linear generators or hydraulic pumps to convert the vertical motion of the wheels into electrical or hydraulic energy. This energy can then be stored in batteries or accumulators and used to power other vehicle systems or assist in propulsion. Regenerative suspension can increase EVs' range and efficiency by recovering some energy that is otherwise lost during driving.
• Air suspension: Air suspension is a type of suspension system that uses air springs instead of metal springs to support the weight of the vehicle. Air springs are flexible rubber bags that are filled with compressed air. Air suspension can use valves, compressors, reservoirs, and sensors to regulate the air pressure in each air spring according to the load and road conditions. Air suspension can improve EVs' comfort, NVH, and adaptability by providing a smoother, quieter, and more customizable ride.

Conclusion

Suspension is an essential component of any vehicle, but especially for electric vehicles, which have different characteristics and requirements than ICE vehicles. EVs need a suspension system that can cope with their weight distribution, regenerative braking, and drive modes and that can enhance their performance, comfort, and efficiency. Some of the technologies that can achieve this are active suspension, regenerative suspension, and air suspension, which are already available or under development for EVs. By adopting these technologies, EVs can offer a silent but smooth driving experience that can rival or surpass that of ICE vehicles.