3 Reasons Why Automakers Switched to Electric Power Steering – Jalopnik

While we wait for the highest levels of automated driving to take the power to steer from our warm, living hands, power steering systems continue to evolve. A novelty when it appeared in the 1991 Acura NSX, electric power steering (EPS) arrived in the 2014 Infiniti Q50 as a true harbinger of the future. Since then, electric power steering has become the common choice for automakers, even if enthusiasts aren’t necessarily happy with it.

Until the 1951 Chrysler Imperial came along with its hydraulically assisted system, driving a passenger car could be classified as a workout: steering without assistance feels heavy. In a lightweight sports car, or something like a 1951 Volkswagen Beetle with the engine hanging over its butt, that might not be so bad. But in a large front-engine sedan, you felt the weight of the car on the front wheels, especially when parking and turning.

Hydraulic power steering completely changed the game, making it easier to turn the steering wheel and change direction quickly. These benefits offset the additional weight and complexity of moving parts that a hydraulic system requires.

Three quarters of a century later, car manufacturers are still trying to balance comfort and complexity, with safety paramount. The move from hydraulic to electric power steering takes all of that into account, with technology that is more efficient, adaptable and works well with other advanced features.

In 1975, Congress established the first CAFE (Corporate Average Fuel Economy) standards, raising manufacturers’ fleet requirements from about 13.5 miles per gallon to 27.5 mpg in 1985. By 2031 this would be a healthy 50 mpg, but someone with a magic marker recently lowered that to just 34.5 mpg. Either way, failure to meet CAFE standards could cost automakers billions in fines if the government decides to enforce them. And electric power steering helps carmakers avoid potential fines by getting the most out of every liter.

Hydraulic power steering uses a pump, some valves, hoses, and a pressurized cylinder full of power steering fluid to provide the juice that helps turn the steering rack. The pump that makes this all work is driven by a motor pulley. When the engine is running, the pump is pumping, even if you are not steering. This demand on the engine consumes power and fuel.

Electric power steering systems replace the pump and pulley with computers and motors, turning them on only when steering input is needed. In hybrids and cars with combustion engines, this means no power is lost to a parasitic steering system, improving fuel efficiency – by as much as 3%, according to BMW. In addition, EPS parts are lighter than those in a hydraulic system, so there is less weight to carry. All of this drives down automakers’ CAFE numbers and keeps them out of the corporate box.

Sometimes a bug and a feature are the same. With their sometimes inactive motors mounted on the steering column or steering rack to muffle things up, the early EPS systems in some enthusiast cars sucked the human senses out of the equation, while hardcore performance folks preferred the precision and feel of hydraulics. That’s less of a concern for the daily driver. Either way, the move to electric power steering ultimately gives automakers the advantage of adaptability.

Over time, automakers have learned how to better calibrate and tune their EPS systems. Companies can filter sensation levels and make settings selectable, so performance-oriented drivers can choose how aggressively the electronics behave. Those electronics can be expensive to replace if something breaks. On the other hand, there is no power steering fluid to maintain, and removing pulleys and pipework frees up space.

This allows car manufacturers to adapt to different design needs. In addition to column and rack-mounted setups, there are also modular EPS systems and rear wheel steering components. The next frontier completely omits the mechanical connection between the steering rack and the steering box: Mercedes-Benz introduces ‘steer-by-wire’ in the upcoming EQS facelift. Without having to worry about designing around a steering column, you can theoretically place the steering wheel anywhere in the car where you can run a cable.

On pub trivia nights, hydraulic power steering would be a kind of trusted, competent teammate who knows the answers but doesn’t participate. Electric power steering is more like the friend who not only plays along, but reads the lips of the genius across the room to get the winning information. And would like to tell you.

EPS integrates better with other vehicle systems than hydraulic power steering. The sensors and electronic control unit can monitor things like steering angle, road imperfections and wheel speed – and then pass the data to other control units in the wider system – from the ABS box that pumps the brakes to the car’s main computer that controls the throttle.

Love them or hate them, advanced driver assistance features are not only here to stay, but drivers are also becoming less wary of hands-off steering assistance. Features such as lane keeping assist, self-driving and self-parking all communicate with the steering system.

And soon, these could all be legally required features. The National Highway Traffic Safety Administration is on track to make automated emergency braking mandatory by 2029. Forward collision and lane departure warning systems are both listed as collision avoidance systems as outlined in federal law, pending a compliance date. Electric power steering helps automakers enable these features now and prepare for the future.