Electronic Power Steering (EPS) is now commonplace in vehicles.
Traditionally, car buyers were faced with two potential power assisted steering systems - electronic or hydraulic. Both have been available for decades, but EPS has become much more common - and in fact far more necessary, due to advancements in vehicle safety systems.
We often speak to AA members who have questions about the different systems, so we’ve put together this brief guide.
What exactly is EPS?
EPS typically uses a conventional rack and pinion set up. It’s controlled by the vehicle’s on-board computer, and information from the steering sensors is received by the computer to determine the amount of assistance that’s needed by the driver.
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The electronic motor, which is coupled to the rack or steering column, helps the driver to steer the vehicle when parking and cornering.
EPS vs hydraulic power steering
Before EPS was introduced, hydraulic power steering was the most common form of assisted steering. While some used vehicles still use this system, it’s not without its shortcomings.
Over a period of time, hydraulic components can start to leak fluid. Because it does rely on fluids that need to be changed, hydraulic power steering requires much more servicing than EPS.
The hydraulic pumps also run continuously, so they contribute towards additional fuel use.
Unlike hydraulic power steering, EPS offers potential fuel savings as the electric current is only used when it’s required. When driving on a straight road there is little load on the engine, which is great for cars with a small engine as more power can be devoted to acceleration.
EPS and Lane Keep Assist (LKA)
While there are many pros that come with owning a car with EPS, in many cases it’s essential due to the driver assist technologies that rely on it.
Vehicles in today’s market are commonly equipped with Lane Keep Assist (LKA), but did you know that information from the EPS system is what helps this feature to function correctly? Information is shared between the two systems, allowing small adjustments to the steering that help the driver remain in the lane.
EPS and Electronic Stability Control (ESC)
ESC is another safety system that uses information gathered from the EPS to operate. In a situation where the driver has lost control of the vehicle, the ESC system collects information from the steering angle and torque sensors to apply the brake and throttle in order to help the driver regain control of the vehicle.
From March 1 2020, ESC became mandatory on all vehicle imports coming to New Zealand.
Autonomy responsibilities
As we look towards the future and manufacturers continue to develop automated driving systems, they’ll rely on EPS even more.
Although current automated features are just that – automated rather than autonomous – manufacturers will continue to update cars and improve these abilities, ultimately giving more responsibility than ever to the EPS system.