About automotive four-wheel steering systems

About automotive four-wheel steering systems

Four-wheel steering systems, also known as all-wheel steering systems, are used by automakers for different performance-oriented models and high-end vehicles. The system allows all four wheels of the vehicle to steer in the same or opposite direction at the same time. Conventional steering systems only allow the front wheels of the vehicle to steer while the rear wheels remain locked.

However, cars with four-wheel steering systems are different.

Basic Features of Four-Wheel Steering Systems
Also known as a four-wheel steering system, the use of a four-wheel steering system allows the front and rear wheels to turn in the same direction or in parallel at the same time.

Four-wheel steering vehicles do not require a lot of steering space as compared to conventional two-wheel steering vehicles. Four-wheel steering technology allows the vehicle to steer with a longer response time and maintain stability at high speeds.

Simply put, with this system, all four wheels can be turned either synchronously or in reverse, thus increasing the agility of the vehicle at both high and low speeds.

Types of Four-Wheel Steering Systems
There are two types of automobile steering wheels
There are two types of four-wheel steering systems for automobiles – passive and active.
There are two types of four-wheel steering systems – passive four-wheel steering and active four-wheel steering. Let’s review them in detail.

Passive four-wheel steering
In a wheel-based four-wheel steering system, the rear wheels are mechanically connected to the front wheels. This means that the front and rear wheels turn together, but at a smaller angle. The main purpose of this system is to improve the stability and maneuverability of the vehicle at high speeds.

At lower speeds, when the vehicle turns, the rear wheels turn slightly in the opposite direction to the front wheels. This reduces the turning radius of the vehicle and improves maneuverability. Passive four-wheel steering systems do not use sensors.

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Active Four-Wheel Steering
Active four-wheel steering systems use sensors to monitor different factors, including vehicle speed and steering angle.

Active four-wheel steering systems use an electronic or hydraulic system to control the movement of the rear wheels, rather than relying on the front wheels. This allows the rear wheels to steer in the same direction as the front wheels, resulting in clearer steering handling and low-speed maneuverability of the vehicle.

On the other hand, when the vehicle is traveling at higher speeds, the rear wheels steer in the opposite direction of the front wheels, thereby improving stability and safety in lane changes.

Stages of four-wheel steering
Four-wheel steering works on the basis of three phases
The four-wheel steering system is divided into three stages
The four-wheel steering wheel operates in three phases: negative, positive and neutral.

Negative Phase
In negative phase, the front and rear wheels move in different directions. When the two axles move in opposite directions, the bending radius decreases. As a result, the car requires less space to park, which is very beneficial in places where traffic and parking are a problem.

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Neutral stage
In this stage, only the front wheels turn to the right or left and the rear wheels remain straight or neutral. This is the medium speed drive used in conventional cars.

Forward Stage
In the forward phase, the rear and front wheels move in the same direction. This movement of the front and rear axles helps the 4W car to change lanes easily while driving on the highway. During this phase, the vehicle usually travels at higher speeds for better maneuverability and agility.

Benefits of 4WD
Four-wheel drive has many benefits for automobiles
Four-wheel steering provides more agility, handling and maneuverability
There are many benefits of four-wheel steering. Some of these include

Better maneuverability
Four-wheel steering reduces the turning radius of the vehicle. This makes driving in tight places, such as parking lots or urban environments, easier. The rear wheels steer in the opposite direction of the front wheels, which improves maneuverability and makes parking and turning around easier. For example, General Motors’ Hummer electric vehicle uses four-wheel steering to improve maneuverability.

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Improved Stability
A four-wheel steering system improves stability at high speeds. The rear wheels steer in a slightly opposite direction to the front wheels, providing better stability and control when changing lanes or turning. In short, this reduces the risk of oversteer and improves the overall dynamics of the vehicle. Honda Fun Fact: Some of their cars use four-wheel steering.

Improved Handling
Four-wheel steering (or 4WD) improves a vehicle’s handling by actively adjusting the angle of the rear wheels. This makes the vehicle more responsive to steering inputs and more precise and agile when driving. The improved handling of a 4WS vehicle is noticeable when driving or maneuvering the vehicle at high speeds.