Last modified: Feb 3, 2024

Suspension

The suspension is one of the essential parts of an EV drivetrain. Again, EVKX.net gives you all details.

What is the purpose of suspension?

The purpose of suspension on cars is to provide a smooth and comfortable ride for the passengers while also ensuring that the vehicle is stable, controllable, and safe to drive. The suspension system serves several vital functions, including:

  • Maintaining tire contact with the road surface: The suspension system keeps the wheels in contact with the road surface, essential for traction, steering, and braking.

  • Absorbing shock and vibration: The suspension system absorbs shock and vibration from the road surface, which helps to minimize the impact of bumps and rough roads on the vehicle and its passengers.

  • Supporting the weight of the vehicle: The suspension system supports the weight of the vehicle, including the chassis, engine, passengers, and cargo.

  • Providing stability and control: The suspension system helps maintain the vehicle’s stability and control during cornering, braking, and acceleration.

  • Enhancing handling and performance: A well-designed suspension system can improve the handling and performance of the vehicle, allowing it to handle corners, curves, and other obstacles with greater ease and precision.

Overall, the suspension system plays a crucial role in ensuring the vehicle’s comfort, safety, and performance.

Mercedes EQS Suv Offroad

What are the parts of a suspension system?

The main parts of a suspension system in a car typically include the following:

  • Springs: These are the primary components that absorb and store energy when the suspension compresses and release the energy when it rebounds. They can be made of steel coils, air bags, or other materials.

  • Shock absorbers or dampers: These are designed to reduce the oscillations caused by the springs by dissipating the energy stored in the springs. They also help to maintain tire contact with the road surface by controlling the rebound and compression of the springs.

  • Control arms: These are typically made of steel and connect the wheel hub assembly to the vehicle’s chassis or subframe. They help to control the wheel’s movement while allowing for some degree of lateral and longitudinal movement.

  • Sway bar or stabilizer bar: This component is designed to minimize body roll and improve stability during cornering by connecting the left and right wheels together.

  • Struts: These are similar to shock absorbers but also serve to support the weight of the vehicle. They are commonly used in MacPherson strut suspension systems.

  • Bushings: These are small rubber or polyurethane components that are used to isolate and dampen vibrations and noise between different components of the suspension system.

Overall, the suspension system is a complex assembly of components that work together to provide a smooth and comfortable ride while maintaining stability, control, and safety.

Bilstein dampers and springs

Constructions

The manufacturers construct the EVs with different types of suspension, but there is some typical design.

MacPherson strut

The MacPherson strut is an automotive suspension system that uses the top of a telescopic damper as the upper steering pivot. Car manufacturers use MacPherson strut as the front suspension on medium to low-priced EVs. The name comes from the engineer Earle S. MacPherson, who invented and developed the design.

A MacPherson strut uses a wishbone or a substantial compression link stabilized by a secondary link, which provides a mounting point for the hub carrier or axle of the wheel.

McPherson front suspension Audi Q4

Pros MacPherson strut

  • Simplified design: MacPherson struts have fewer components than traditional shock-absorber-and-spring systems, making them easier to install and maintain.
  • More space-efficient: They take up less space than other types of suspension systems, leaving more room for other components, such as the engine and transmission.
  • Good handling: MacPherson struts provide good handling and stability on the road, especially in high-speed maneuvers and cornering.
  • Cost-effective: They are generally less expensive than other types of suspension systems, making them a popular choice for budget-conscious vehicle manufacturers.

Cons MacPherson strut

  • Limited adjustability: MacPherson struts are not as adjustable as other types of suspension systems, making it more difficult to fine-tune the ride and handling characteristics.
  • Less durable: They may be less durable than other types of suspension systems, especially in harsh driving conditions or off-road use.
  • Bump steer: MacPherson struts can cause a phenomenon called bump steer, which occurs when the suspension geometry changes during cornering, causing the wheels to steer unintentionally.
  • Uneven tire wear: MacPherson struts can cause uneven tire wear, especially when driving on rough roads or over bumps.

Overall, MacPherson struts are a popular choice for many vehicles due to their simplicity, cost-effectiveness, and good handling characteristics. However, there may be better choices for some driving situations, and some drivers may prefer other types of suspension systems that offer more adjustability and durability.

Double Wishbone

Double wishbone suspension is a type of independent suspension system commonly used in high-performance and luxury vehicles. The suspension design features two A-shaped control arms (also called wishbones) that are connected to the chassis and the wheel hub assembly.

The upper and lower wishbones work together to control the vertical movement of the wheel, while allowing for some degree of lateral and longitudinal movement.

Mercedes-Benz EQE Suspension with double wishbone

Pros of Double Wishbone

  • *Improved handling: The double wishbone suspension allows for more precise control of the wheel’s movement, resulting in better handling, steering response, and stability, especially during high-speed cornering.
  • Better ride quality: The design reduces the impact of bumps and road imperfections, resulting in a smoother ride.
  • Good camber control: The double wishbone suspension allows for better camber control, which is important for maintaining tire contact with the road during hard cornering.
  • More adjustable: The suspension is highly adjustable, allowing for fine-tuning of the handling characteristics, ride height, and suspension geometry.

Cons of Double Wishbone

  • Complex design: The double wishbone suspension is more complex and expensive to design, manufacture, and maintain than other types of suspension systems, such as MacPherson struts.
  • Space requirements: The suspension takes up more space than other types of suspension, which can limit the vehicle’s design and packaging options.
  • Heavy: The suspension can be heavier than other types of suspension systems, which can affect the vehicle’s weight and fuel economy.
  • Cost: Due to its complexity, the double wishbone suspension can be more expensive to repair or replace in case of damage or wear.

Overall, the double wishbone suspension is a popular choice for high-performance and luxury vehicles due to its superior handling, ride quality, and adjustability. However, its complexity, space requirements, and cost can be drawbacks for some applications.

Multilink suspension can be used on both the front and rear axles of a vehicle, depending on the specific application and design of the vehicle. In some cases, multilink suspension may be used on all four wheels, while in others it may be used only on the front or rear wheels. For example, many high-performance sports cars and luxury sedans use multilink suspension on both the front and rear axles to provide superior handling and ride comfort. Meanwhile, some compact cars may use a simpler suspension design on the front wheels, but a multilink suspension on the rear wheels to improve stability and handling. Ultimately, the decision to use multilink suspension on a particular vehicle will depend on factors such as the vehicle’s size, weight, intended use, and performance requirements.

Multilink suspension is a type of independent suspension system that is commonly used in modern vehicles. It is designed to provide superior ride comfort and handling performance by allowing each wheel to move independently of the others. The system consists of multiple links, or arms, that connect the wheel hub to the vehicle’s chassis.

Multilink suspension can be used on both the front and rear axles of a vehicle, depending on the specific application and design of the vehicle. Most Evs use it on rear axle.

  • Improved handling: Multilink suspension systems provide better handling and stability, particularly in high-speed driving situations. They allow the wheels to move independently, which reduces body roll and improves overall cornering performance.

  • Better ride comfort: Multilink suspensions can provide a smoother ride quality by absorbing bumps and shocks more effectively than other suspension types. The suspension can be tuned to provide a comfortable ride without sacrificing handling performance.

Versatile design: Multilink suspension can be designed to suit a wide range of vehicle types and sizes, from small passenger cars to larger SUVs and trucks.

  • Complex design: Multilink suspension systems are generally more complex than other types of suspension, which can make them more difficult and expensive to repair or maintain.

  • High manufacturing costs: The complex design of multilink suspension can also result in higher manufacturing costs, which can increase the price of the vehicle.

  • Heavy weight: The multiple links and arms used in multilink suspension systems can add significant weight to the vehicle, which can affect fuel efficiency and performance.

  • Requires more space: Multilink suspension systems require more space than other suspension types, which can limit the available interior space in the vehicle or make it more difficult to package other vehicle components.

Multilink suspension can be used on both the front and rear axles of a vehicle, depending on the specific application and design of the vehicle. In some cases, multilink suspension may be used on all four wheels, while in others it may be used only on the front or rear wheels. For example, many high-performance sports cars and luxury sedans use multilink suspension on both the front and rear axles to provide superior handling and ride comfort. Meanwhile, some compact cars may use a simpler suspension design on the front wheels, but a multilink suspension on the rear wheels to improve stability and handling. Ultimately, the decision to use multilink suspension on a particular vehicle will depend on factors such as the vehicle’s size, weight, intended use, and performance requirements.

Multilink rear suspension

Leaf Suspension

Leaf suspension is a type of suspension system used in cars, trucks, and trailers, which uses a series of curved metal plates called leaf springs. The leaf springs are mounted on the vehicle’s frame and axles, and they work together to provide a smooth ride and support the weight of the vehicle.

The way leaf suspension works is that the leaf springs are arranged in a stack, with the longest leaf at the bottom and progressively shorter leaves stacked on top. The leaves are clamped together with a center bolt and held in place with metal clips. When the vehicle hits a bump or uneven road surface, the leaf springs compress and absorb the shock, allowing the wheels to move up and down independently of the vehicle’s frame.

Some of the advantages of leaf suspension include:

High weight capacity: Leaf suspension is capable of supporting a high weight capacity, making it ideal for use in heavy-duty trucks and trailers.

Simple design: Leaf suspension has a simple design with fewer components, which makes it less expensive to manufacture and repair.

Good durability: Leaf suspension is durable and can withstand heavy loads and rough terrain.

Some of the disadvantages of leaf suspension include:

Stiff ride: Leaf suspension can provide a stiff ride compared to other types of suspension systems, which can be uncomfortable for passengers.

Limited adjustability: Leaf suspension is not as adjustable as other types of suspension systems, which can make it difficult to fine-tune the suspension for optimal performance.

Poor handling: Leaf suspension can cause the vehicle to bounce and sway on rough roads, which can affect the vehicle’s handling and stability.

Noise and vibration: Leaf suspension can produce noise and vibration when driving, which can be unpleasant for passengers.

Air suspension

Air suspension is a type of vehicle suspension system that uses compressed air to provide support and cushioning. It consists of airbags, a compressor, and a control system that regulates the amount of air in the bags to adjust the height and stiffness of the suspension. This replaces the spring in conventional systems.

When the vehicle is in motion, the air compressor pumps compressed air into the airbags to maintain a consistent ride height and cushion the vehicle from bumps and vibrations. The control system uses sensors to detect changes in the road and adjusts the air pressure in the bags to maintain a smooth ride.

One of the primary advantages of air suspension is that it provides a more comfortable ride than traditional suspension systems. It can also be adjusted to accommodate different loads and road conditions, making it ideal for vehicles that carry heavy loads or operate on rough terrain.

Another advantage is that air suspension can help improve handling and stability by lowering the center of gravity of the vehicle. It can also help reduce wear and tear on tires and other suspension components.

However, there are some potential drawbacks to air suspension. It can be more expensive to repair or replace than traditional suspension systems. It can also be more complex, with more components that can fail or malfunction.

Additionally, some drivers may prefer the feel of a traditional suspension system, which can be more responsive and provide a better “road feel.” Finally, the compressor that powers the air suspension system can consume more energy than a traditional system, which can result in lower fuel efficiency.

Some models only use the air suspension to adjust for different loads, trying to keep the ride height at the same level. These models typically only have air suspension at the rear axle. Examples are the Mercedes EQC and BMW I4.

Front Air Suspension

On other models, the driver can set the drive height based on drive mode. For example, below is a diagram for the Audi Q8 e-tron showing the ride height for the different modes.

Suspension modes Audi Q8 e-tron

Adaptive damping

Adaptive damping suspension is a technology that adjusts the damping of a car’s suspension system in real-time based on the driving conditions and the driver’s preferences. The damping of a suspension system determines how much the suspension compresses and rebounds when the car encounters bumps and rough road surfaces.

In an adaptive damping suspension system, sensors are used to detect the motion of the car, including its speed, acceleration, and the state of the road surface. This information is then used by a computer to adjust the damping of the suspension system in real-time. The computer can also take into account the driver’s preferences, such as a sporty or comfortable driving style.

There are several different types of adaptive damping suspension systems, but they all aim to provide a smoother, more comfortable ride while also improving the car’s handling and stability. Some systems use magnetic fluid in the shock absorbers to adjust the damping, while others use electronic solenoids to control the flow of hydraulic fluid.

Overall, adaptive damping suspension can improve the driving experience by providing a more comfortable ride and better handling, especially on uneven or bumpy roads.

Audi RS e-tron GT adaptive air suspension

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