Electric Power Steering: The Pros And Cons
When talking about the evolution of cars, there are several notable milestones that can’t be omitted. In today’s world, it’s the fight against high emissions, engine downsizing, and electric vehicles (EVs). Elsewhere, it’s the advancement of infotainment systems and the incorporation of advanced safety technologies.
- Base Trim Engine
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Electric
- Base Trim Transmission
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Single Speed Automatic
- Base Trim Drivetrain
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Front-Wheel Drive
But did you ever take a moment to stop and think about power steering? The one thing many of us take for granted. This ‘must be there’ system has a rich history that spans more than a century, yet we only think of it when it stops working. These days, electric power steering (EPS) is the go-to setup in most vehicles, but there is ample to dissect on the subject that makes our driving experiences that much less of a chore.
In this piece, we dive into the innovation that was in existence long before the first car came to be. Here, we will answer: What is electric power steering? We’ll also find out how it took a World War to show its usefulness.
Power steering is a continuously evolving mechanism found in all vehicles. There are different variations of this technology, with electric power steering emerging as the favored type in recent years and its pros outweighing the cons. We take a closer look at this power steering design here.
A Brief History On Power Steering
It is not common knowledge that power steering has been around for 149 years. And no, we are not making this up.
The Beginnings Of Power Steering And World War 2
Power steering was first patented in 1876 – long before the first automobile saw the light of day. But it became something to take note of during the 1920s when Francis Davis introduced the first power steering system to be used on a car, albeit in extremely limited numbers and with very low commercial success. This was preceded by Frederick Lanchester, who designed and showcased a hydraulic system in 1902, which also failed to garner much traction.
However, it was during World War II that power steering became, shall we say, mainstream. The system designed by Davis was adapted for military application to ease the challenges associated with commanding heavy war machines. When the war ended in 1945, more than 10,000 war-prepared vehicles were equipped with power steering – globally.
Six years later, in 1951, Chrysler implemented the first commercial power steering system, and more than 1 million vehicles were fitted with power steering by 1953.
How Does Power Steering Work?
Power steering is not just a system that works as a standalone entity, but in tandem with numerous parts.
Working To Alleviate Strain
Like with the vehicles in WW II, a power steering system’s primary purpose is to alleviate any unnecessary strain it might put on a driver. As such, the system depends on many mechanical parts – be it active or passive – to improve the control drivers have over their vehicles.
As for electronic power steering, the vehicle’s electrical system sends energy to an electric motor that, in turn, provides steering assistance. Depending on how much steering input a driver applies and how much torque is sent to the wheels at that given moment, a computer will apply the required amount of assistance. The three types of electric power steering are as follows.
Column-Mounted EPS
The electric motor is located on the steering column. This design, where the motor is positioned just below the steering wheel, is compact and lightweight.
Rack-Mounted EPS
The electric motor is located on the steering rack, with the latter attached to the steering linkage. With this design, the steering feel is more direct, but it comes with the caveat of being more complex and heavier than column-mounted EPS.
Belt-Driven EPS
Here, the electric motor is located away from the steering mechanism, and steering assistance is provided by a belt. Power delivery is, generally, more efficient, and the packaging options are more flexible. However, maintenance can be more regular.
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Electric Power Steering Vs. Hydraulic Power Steering
Electric power steering and hydraulic power steering (HPS) are two different systems, but each has its strengths. Hydraulic power steering systems have increasingly been replaced by electric ones.
Same-Same But Different
EPS utilizes an electric motor that is controlled by sensors and a computer. Depending on how much steering input is applied, computerized sensors ‘tell’ the motor how much assistance is needed at that specific moment. Be it at higher speeds or maneuvering into a parking space, ESP is designed to take the load off the steering wheel.
HPS, on the other hand, has been around for longer and uses fluid pressure to assist in the steering action. The engine belt drives the power steering pump, and a fluid flows into a cylinder when the wheels are turned. Of course, those who appreciate the joys of driving will quickly note the direct and linear feel that HPS offers, making the communication between driver and car more natural.
However, some of HPS’s drawbacks include:
- More strain on the engine
- Poorer fuel efficiency
- More moving parts (including the pump, fluid lines, valves, etc.), meaning higher wear and tear
- Higher repair costs
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The Pros Of Electric Power Steering Systems
Below, we list five common advantages of EPS systems.
Better Fuel Efficiency
EPS systems are not in a state of constant running like HPS, which lowers the reliance on the engine. EPS only consumes energy/power when the steering wheel is turned.
Easier To Maintain
EPS systems do not have as many moving parts, and the designs are, for the most part, more simplistic. This results in reduced wear and tear and a lesser reliance on steering fluid.
Works With ADAS
While ADAS (Advanced Driver Assistance Systems) aims to improve vehicle safety, EPS can be easily integrated. The amount of steering assistance also varies based on the vehicle speed and the driving conditions.
Lower Weight
EPS systems do not require as much installation space in the engine bay thanks to their compact, lightweight designs.
Better Vehicle Handling
Steering feedback is more precise and responsive, and more consistent at different speeds. This isn’t always the case, though.
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The Cons Of Electric Power Steering Systems
Below, we list five common disadvantages of EPS systems.
Less Steering Feedback
HPS systems provide greater steering feedback to EPS, which driving enthusiasts might lament as they chase more engagement from behind the wheel.
Potential For Something To Go Wrong
Because EPS systems rely on sensors and electrical components, the risk of (sensor and/or electric motor) failure remains at play.
Hefty Repair Costs
Though the design and weight of EPS systems are compact and lighter than HPS, the accompanying repair costs can be high due to the electronic components’ complexity.
Reliance On Electrical System
EPS may work without the engine acting as the power source, but it is dependent on the vehicle’s electrical system. If this system is compromised, EPS’ assistance may not come into play.
Setup Is Key
If the EPS system is not correctly calibrated, steering feel is less predictable.
A Certainty: Car Steering Systems Will Continue Evolving
Considering how far power steering has come since its original patent almost 150 years ago, it’s a given that the systems surrounding it will continue to evolve.
What Can We Expect?
The automotive world is always changing, and we can prepare ourselves that there will always be another patent, another invention, another breakthrough in this sphere. That includes power steering. EPS is proving to be an efficient add-on to vehicles given its energy-saving features. As such, expect it to be integrated more aggressively with the brakes, suspension, and ADAS.
Steer-by-Wire technologies are gaining more traction by the day as physical mechanical parts are replaced by electronic signals. The aim? Better steering precision and response times. This technology is still in its early stages, but in-production vehicles like the Lexus RZ are proving that it will soon trickle down to cheaper segments. We previously experienced Steer-by-Wire technology in the Lexus RZ.
Expert Opinion
Although a Lexus team member asked journalists to exercise caution when initially setting off in models equipped with Steer by Wire due to its more direct responses, we found the system pretty easy to adjust to in normal driving at slower speeds. Only minor side-to-side steering movements are needed to direct the RZ 450e through a series of moderately quick, smooth sweeps, where the system felt at its most enjoyable, and certainly more decisive than the traditional steering.Crucially, the reliance on electric processing of information does not make the driving the RZ feel overly artificial; yes, sensations are far more muted than they’d be in a sports car, but entirely within the realm of the typical luxury crossover.
As cars rely more and more on self-driving technologies, we can expect steering wheels to lose their permanent position in the cabin. Already, we’ve seen patents for folding steering wheels that can be moved out of the way entirely when not in use, freeing up cabin space.
A Future Worth Thinking About
Power steering has come a long way since 1876 and has become a part of our lives since being thrown into battle as a military necessity.
This technology has made driving physically less demanding, and the advancements in EPS have made it more efficient and adaptable. However, the electric systems in EPS often make the driving experience too filtered and more reliant on sensors and algorithms. So, we have to ask the first question: Are we favoring convenience or connection?
There is no denying the tangible benefits of ESP, but as AI becomes more prevalent and integrated in our lives, it is only a matter of time before we no longer take note – or care – about the driving experience. The rapid advancements in self-driving technology and AI uptake will soon force us to ask the second question: Do we want our cars to do more for us, or more with us?
Sources: Buy Auto Parts, J.D. Power, National Power Steering
