We tend to take power steering for granted, as these days you can find power steering systems in practically every car sold today. While power steering has been a common feature of cars for over 60 years now, there was a time when no vehicles had any kind of power steering at all.
In this article, we'll be going over the history of power steering. We'll explain how exactly it was that the first power steering systems were developed, and we'll also explain how power steering systems work in general.
How Does Power Steering Work?
Before we get into the actual history of power steering itself, we figure it might be a good idea to go over how power steering systems work in brief. There are a few kinds of power steering systems that have been used over the years, and they all work fairly differently.
Hydraulic Power Steering
Hydraulic power steering was the first kind of power steering to be widely available in passenger vehicles and was the most common type of power steering used in such vehicles from the 1950s to the early 2000s. While these systems generally work fine, they have a few disadvantages compared to the electric power steering systems that came after them.
Hydraulic power steering systems work by using hydraulic fluid to apply additional force to the wheels when the steering wheel is turned. The pressure of this fluid is generated by a pump that is driven by a belt connected to the engine.
Unfortunately, there are some drawbacks to using a hydraulic power steering system. For one, such a system usually has a negative effect on an engine's fuel economy; because the hydraulic pump for the power steering is driven by the engine, this means that some of the engine's power is lost to the pump.
Another drawback is the fact that hydraulic power steering systems need hydraulic fluid in order to work. The fluid has to be changed periodically, and if any of the hydraulic lines that carry the fluid leak, then the power steering system stops working.
One fairly significant issue with a lot of early hydraulic power steering systems was that the steering wheels received the same level of boost regardless of the speed the car was travelling at. This was fine at slow speeds, since it made the wheel easier to turn, but at high speeds the steering could feel overly light and unstable.
Finally, there's the fact that hydraulic power steering systems are more complicated than electric systems, thanks to all the hydraulic hoses and other components that the system requires.
Electric Power Steering
Electric power steering systems are what you'll find on most modern cars. In an electric power steering system, there is still a mechanical link between the steering wheel and the steering assembly, but the wheels are assisted by an electric motor instead of hydraulic fluid.
Because electric power steering systems aren't driven by the engine, they're a lot more fuel efficient than hydraulic systems. They're also less complicated systems overall, which makes them considerably easier to make and maintain.
Another advantage of electric power steering systems is that they can adjust themselves to provide more or less resistance depending on the speed of the car. For example, the steering can be light at low speeds, but become heavier at high speeds.
Electro-Hydraulic Power Steering
Finally, we have electro-hydraulic power steering systems. These systems are by far the least common of the three, but they have appeared in a few cars over the years.
Electro-hydraulic power steering systems are essentially a hybrid of hydraulic and electric systems. Like hydraulic systems, they use hydraulic fluid to provide force to the wheels, but the pump that circulates the hydraulic fluid isn't driven by the engine; instead, it's driven by a separate electric motor.
Basically, this kind of system is a little better than a purely hydraulic system, but not as good as an electric one; you get better fuel efficiency by using an electric motor to drive the pump instead of the engine itself, but electro-hydraulic power steering systems don't have the same array of features that fully electric systems have.
How Power Steering Came to Be
At first glance, power steering seems like a thing invented to be a simple convenience, but this is not the case. Prior to the invention of power steering, vehicles were a lot more difficult to drive, particularly at low speeds. It was basically the driver versus all the friction of the tires on the road.
The idea for power steering supposedly came about even before the invention of the automobile itself. In 1876, a man named G.W. Fitts apparently designed and patented an early design for a power steering system, but most of the information concerning how his system worked or even who Fitts actually was seems to be lost to time.
In 1900, a Pennsylvania man named Robert E. Twyford patented a four-wheel drive system that also included a power steering system. However, this system was entirely mechanical, and failed to really catch on.
The first big development for power steering came in 1926, when Francis Davis, an engineer with the Pierce-Arrow Motor Car Company, created the first actually practical hydraulic power steering system. For the most part, Davis' power steering systems were used on heavy military vehicles that needed the extra steering assistance.
In between working for Pierce-Arrow and creating power steering systems for military use, Davis worked with General Motors to produce a power steering system for their road cars. At the time, however, his systems were deemed too costly to produce for the mass market, so power steering failed to make a real appearance.
That all changed in the '50s, however, when the Chrysler Corporation began producing their own power steering systems based on the original design of Davis' system. Davis' patents for the system had expired some time previously, so Chrysler was free to borrow as many ideas from him as they wanted.
This new power steering system, dubbed the "Hydraguide", made its first appearance in the 1951 Chrysler Imperial. Soon afterwards, General Motors used the designs Davis had made for them previously to complete their own power steering system, which debuted in all of Cadillac's cars sold in 1952.
It didn't take long afterwards for power steering to catch on, and by the end of the decade, over 3.5 million cars in America alone had power steering. These days, only a tiny fraction of new cars come with unassisted steering, and most of these are small, lightweight sports cars.