A power steering system is a mechanical device installed on a vehicle that assists drivers in steering by reducing the amount of steering effort required to turn the steering wheel, allowing the vehicle to turn or navigate at lower speeds. Hydraulic or electric actuators give regulated energy to the steering system, allowing the driver to move the steered wheels with less effort when travelling at normal speeds, and reducing the physical effort required to turn the wheels significantly when the vehicle is stopped or going slowly. Power steering can also be designed to simulate the forces operating on the steered wheels.
An actuator, a hydraulic cylinder that is part of a servo system, is used in hydraulic power steering systems for cars to help with steering effort. The steering wheel and the linkage that steers the wheels have a direct mechanical relationship in these systems. This means that even if the power-steering system fails (to augment effort), the car can still be controlled manually. Instead of hydraulic systems, electric power steering systems employ electric motors to give assistance.
The rest of the power steering system controls the power to the actuator (motor in this case), just as it does with hydraulic versions. Other power steering systems, such as those seen in the largest off-road construction trucks, do not have a direct mechanical connection to the steering linkage; instead, they rely on electricity. By comparison with aviation’s “fly-by-wire,” these systems with no mechanical connection are also referred to as “drive by wire” or “steer by wire.” Electrical cables that transmit power and data, not thin wire rope mechanical control cables, are referred to as “wire” in this context.
Some construction trucks have a two-part chassis with a robust hinge in the middle that allows the front and rear axles to steer the vehicle by becoming non-parallel. To steer, opposing hydraulic cylinders move the frame portions relative to each other. Electric power steering (EPS) is a key technology for highly automated driving. The Bosch EPS variants meet the requirements for small, mid-range, sports cars as well as light commercial vehicles. The EPS has an electric motor which controls the vehicle steering. With an electric motor the EPS controls and assists vehicle steering and provides an optimal and enjoying steering feel. Additionally, the new generation of control units provide security in case of an error. The electric interface enables highly-automated driving with maximum security till SAE-Level 4.
By using an electric motor that is directly attached to the steering gear/column, electric power assisted steering (EPS) provides more assistance than standard hydraulic power steering. EPS aids in the effort required to steer an automobile using mechanical linkage. Sensors monitor steering column torque and motion, and the electric motor is controlled by a computer module. Because parasitic losses are reduced, EPS enhances car handling, gives directional control for the driver, and increases fuel efficiency slightly. Other benefits of EPS include the ability to software-modify a design for specific driving modes or different automobile models (e.g., sport vs. luxury.) Despite the fact that EPS is less expensive to produce than traditional hydraulic systems, a mechanical linkage such as rack and pinion steering is commonly used as a backup. EPS is expected to overtake hydraulic steering as the de facto method of steering in the automotive industry.
Hydraulic power steering systems work by multiplying force supplied to the steering wheel inputs to the vehicle’s steered (typically front) road wheels using a hydraulic system. A gerotor or rotary vane pump powered by the vehicle’s engine provides hydraulic pressure. A force is applied to the steering gear by a double-acting hydraulic cylinder, which then steers the roadwheels. The steering wheel controls the flow to the cylinder by operating valves. The greater torque supplied to the steering wheel and column, the more fluid the valves allow to pass through to the cylinder, and thus the more force is applied to move the wheels.
A torque sensor — a torsion bar at the lower end of the steering column – is one device for measuring the torque applied to the steering wheel. The steering column, as well as the top end of the torsion bar, revolve with the steering wheel. The torsion bar will twist by an amount proportional to the applied torque since it is thin and flexible, and the bottom end normally resists being turned. A valve is controlled by the difference in position between the torsion bar’s opposite ends. The valve permits fluid to flow to the cylinder that assists with steering; the higher the torsion bar’s “twist,” the greater the force. The flow rate delivered by the hydraulic pumps is precisely proportional to the engine speed because they are positive displacement pumps.
This means that the steering would naturally work faster at high engine speeds than at low engine speeds. Because this is undesirable, at high engine speeds, a restricting orifice and flow-control valve direct some of the pump’s output back to the hydraulic reservoir. When the piston of a hydraulic cylinder reaches the conclusion of its stroke, a pressure relief valve prevents a dangerous build-up of pressure. The steering booster is set up in such a way that it will keep working even if the booster fails (although the wheel will feel heavier).
The loss of power steering can have a substantial impact on a vehicle’s handling. The owner’s manual for each vehicle includes instructions for checking fluid levels and maintaining the power steering system on a regular basis. The working liquid, often known as “hydraulic fluid” or “oil,” is the medium that transmits pressure. Mineral oil is used in most common working fluid. Variable-assist power steering systems contain an electronic control valve that reduces the hydraulic supply pressure as the vehicle’s speed increases.
Overview of the Global Automotive Electronic Power Steering Market
In the previous few years, the automotive industry has gone through various periods of advancements in terms of power, design, and efficiency. Automobiles can now operate in a variety of terrains that were previously only suitable for smooth roads because to advances in technology and automation. The right steering design gives the vehicle with stability and mobility on any terrain. The steering system is made up of a number of various linkages that are designed to turn the vehicle in the smallest possible radius without actually turning it. Unlike traditional steering, modern car electronic power steering incorporates a variety of electrical systems that help to reduce power and provide precise turning.
The electronic power steering system can improve both the driving pleasure and the efficiency of the vehicle. Previously, electronic power steering was primarily found in high-end vehicles or sports utility vehicles (SUVs). Electronic power steering’s consistency has improved dramatically in recent years, and as a result, it has increased its presence in nearly every vehicle category. The modern electronic power steering system is more compact and includes a variety of other controls and airbags.
