Why We Love Our Power Steering: The Evolution of Car Steering

Posted 5/3/21

Power steering is one of those standard and expected features that modern car drivers take for granted. Though it is standard issue these days, it wasn’t that long ago when parallel parking on a busy city street required more than the correct knowledge of angles and when to cut the wheel, but also the strength and tenacity to wrestle that wheel into submission at a slow speed enough times to get into the space. The invention and popularity of power steering make driving more enjoyable for all—and it also opened up the ability to drive to anyone who has less strength their arms and hands.

Simple Steering in Horseless Carriages: Steering Wheel’s Beginning

At the beginning, of the transition from carriages to horseless carriages, the steering wheel as we know it was not the immediate choice for means of directing the new cars. The earliest means of steering involved a mechanism more like a boat tiller than what we see today. The wheels and axels of the car were fused in a single unit that pivoted around a central point in that axle. There was a post attached to that axle and up to within reach of the vehicle’s driver. From there the driver could with some strength imprecisely steer their car like some sort of land dinghy, with this post as their car’s tiller.

As cars became faster, however, a new method of steering was required that was more precise and did not make the tires scuff along when turning at higher speeds. This is also when the steering wheel became more common. An upgrade developed by Gorge Lenkensperger in 1818 (though typically attributed to the rights owner Rudolph Ackermann) made the steering mechanism separate from the axel itself by putting the wheels on spindles which pivoted on the ends of the axle rather than being fused to it. This was the first in a series of improvements that eventually led to the basics of every car’s steering mechanism today.

Relay Rods and Steering Gears: The Easier to Steer, The Better

From the adaptation of Ackermann’s spindle, the time was right for innovation. The French carriage maker Jeantaud was the first to put together the original version of relay rod which allowed the mechanism that changed the car’s direction to be placed somewhere other than the center area above the axle where it had always been before.

Another innovation came in the form of the steering gear. Not only was it difficult to wrench the weight of the wheel from side to side while directly connected to the front tires, but there was still little room for precision of finesse when steering. This extra steering gear—often in the shape of a worm gear—which was used between the steering wheel and the steering linkage gave the driver more torque to turn the wheel than a direct connection between the two could. This made it easier for drivers to turn the wheel farther with less effort, and is still used in some form today.

But Where’s The Power? Power Steering’s Surprisingly Early Beginning

According to Popular Mechanics, the first example of power steering installed into a car way back in 1876 by someone with the last name of Fitts, “but little is known of it.” Instead, let’s look a bit later on. The first power steering system that was actually put into a production car was in 1951, on the Chrysler Imperial. This was the first example of power steering being used to simplify the life of the average driver by reducing the amount of effort required to turn the steering wheel. The increase in car sizes in the 50’s made power steering a popular feature.

These new cars that were equipped with power steering didn’t need the extra torque to turn the wheel that the previously introduced steering gear made possible, so they began to be equipped with a smaller steering ratio. With a higher steering ratio, it takes more movement of the steering wheel to change the angle of the front wheels, and with a lower ratio it takes less turning of the steering wheel to change those angles. Interestingly, the advent of power steering led to modern steering ratios being somewhat closer to those on the original cars with steering wheels—though thankfully the car rudder was never invited back to the party.

The Three Main Types of Power Steering and What they Mean to You

When power steering was born, there was only one type available: hydraulic power steering (HPS). In hydraulic power steering, the power steering pump—driven by the drive belt—creates hydraulic pressure to assist in the turning of the steering wheel. The main problem with this type of power steering is that it is not terribly efficient. The hydraulic pump is running no matter how much or little the steering wheel is being turned, and its existence siphons a little bit of torque off of the engine to run. As with any hydraulic system, the fluid needs to be replaced periodically, and there is quite a problem if it develops any sort of a leak. Hydraulic power steering was the standard for most of the existence of power steering, from the 1950s to the 2000s.

The second type of power steering still relies upon the tried and true hydraulics that were developed in the 50’s but added the modern benefit of using a separate electric motor to power the hydraulic pump instead of relying on the drive belt to power that motor. These systems are called electro-hydraulic power steering (EHPS) or a hybrid system. Other than the means from which the hydraulic engine gets its power, the EHPS systems are fundamentally very similar to the HPS systems.

Power Steering in the 21st Century: Electric is Now and the Future

Though hydraulics have been the power steering method of choice for nearly a century, power steering is changing in a big way due to the advent of electric power steering (EPS). Instead of using heavy hydraulics to maneuver the steering wheel, EPS steering relies on an electric motor to do all of the heavy lifting in the power steering. The level of assistance given to the driver in turning the steering wheel relies on a number of variables and is driven by numerous sensors. In some cars, the car provides more assistance while going slower speeds, such as when parallel parking or in slow city traffic, and less assistance when going faster highway speeds which gives the driver more of a feeling of control.

Electric power steering removes those parts prone to failure and any weight that is necessary for a hydraulic system. It simplifies the mechanical systems required to run the power steering, and does rely more fully on electronic sensors than ever before.

Though this thought of more control of your car than ever before being turned over to computer sensors may not be overly appealing to the Luddites in the audience, it is interesting to note that these sensors also allow for some of the most intriguing aspects of modern car production. The sensors allow for such modern automotive marvels as as autonomous driving and lane assist. They can be programmed to help the driver park the car or drive confidently into a crosswind, and ultimately simplify any steering eventuality in motoring. Whether or not you want your power steering system to be smarter than you are, it’s fair to say that is more fun than than wrestling your car without power steering around a turn during rush-hour traffic.

Had Your Radiator Flushed Recently? If You Can’t Remember, You Should

Replacing your antifreeze is one of those little car tasks that even the most enthusiastic at-home car hobbyist never quite gets around to completing. Though not a difficult task, it requires one to allow the radiator fluid to cool after getting heated up in the engine several times, which can make that simple task stretch for what seems to be hours. The good news is that your friendly local auto shop would be more than happy to take on that task for you while you are at home doing more important things—like having a beer or watching the big game.

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