POWER STEERINGPower steering is a system that essentially allows the driver to turn the steering wheel of a vehicle with less effort. It also increases ease of manoeuvring during low speeds (for example complicated parking or performing a three-point turn). It provides faster response to directional change & delivers an overall smoother, safer & more controlled drive. Most vehicles use a rack & pinion steering system. The pinion gear is attached to the steering shaft & the rack is attached to the wheels. When you turn the steering wheel, the rotational motion of the pinion is transferred into linear motion of the rack; turning the vehicle’s wheels left or right. It is still possible to steer a car without power steering, however it would require a greater driver force to turn the pinion & move the rack. Virtually all new vehicles manufactured today utilise power steering.
The 3 Types of Power Steering Systems are:
- Electric Power Steering
- Hydraulic Power Steering
- Electro-Hydraulic Power Steering
Electric Power SteeringMost new cars on the market today have Electric Power Steering (EPS). EPS uses an electric motor that is either attached on the steering column or rack. It draws its power from the vehicle’s electrical system to work, rather than the vehicle’s engine. Sensors detect different factors depending on driving conditions; such as how much effort the driver is applying at the steering wheel & the vehicle’s speed, & adjusts the amount of assistance required (more assistance at lower speeds & less at faster speeds). This is called Variable Assist. Because there is no belt-driven hydraulic pump constantly running, & it does not rely on the engine’s power, EPS is superior to hydraulic power steering in fuel efficiency.
Hydraulic Power SteeringHydraulic Power Steering (HPS) uses the force of hydraulic fluid to deliver hydraulic pressure to the steering system. The fluid is pressurised by a pump driven by a belt attached to the vehicle’s engine. The harder the driver turns the steering wheel, the more fluid flows to the hydraulic cylinder, & more force is applied for steering assistance . The pump runs continuously, even if there is no need for assist (for example if the car is driving straight). Because of this, it is not the most energy efficient option. There are also more components to this type of power steering compared to EPS & therefore there are more components that will need to be maintained & replaced over time. This includes replacing hydraulic fluid, the belt when it gets too worn, & the possibility of a leak occurring.
Electro-hydraulic Power SteeringElectro-Hydraulic Power Steering (EHPS) is a hybrid of the previous two systems. Only a few types of vehicles use this system, including some heavy-duty commercial vehicles & large farm equipment. It uses hydraulic pressure from a pump, but run off an electric motor, rather than off the engine. This system helps to reduce energy waste, but doesn’t include all of the features possible of EPS.
Signs there is a problem with your power steering:
- The steering wheel feels heavy or stiff.
- The steering wheel is slow to respond.
- There is a whiny or squealing noise when you turn the steering wheel.
- The Power Steering System warning light comes on (a yellow, orange or red steering wheel symbol with an exclamation point, or the letters ‘EPS’).
- The power steering fluid in the reservoir darkens (typically from a red or amber to a darker, brownish colour).
- You notice a leak.
- It takes more effort than normal to turn the steering wheel.