Just Like the Jets: Infiniti Q50 Rocks the Steer-by-Wire System
Published March 11, 2014
Turn left. Now, turn right. Ever wonder how your steering system works? Naw, most people don’t care, as long as they get to work on time. But you, you really want to know. On older cars, the system is surprisingly clunky and a little dysfunctional in terms of design. On newer cars, it’s practically “invisible.” Here’s how it all works so that you can get to work, or home, or to your kid’s baseball game.
Almost all cars on the road today have a mechanical steering system, where a linkage runs from the steering wheel down to a steering rack, and then to the wheels. When you turn the steering wheel, it turns the vehicle one way. When you turn the steering wheel another way, the car responds. It’s like magic, except it’s not.
It operates on very old and sound engineering principles. However, the system itself is a bit clunky. There’s a lot that can go wrong, and often does, on older vehicles. “Slop” in the steering wheel can be caused by failing rubber bushings in the steering system, and the actual steering column has the potential to impale the driver in a head-on collision, at least theoretically.
There’s also the problem of steering ratio. The steering ratio, in simple terms, determines how many turns of the wheel are required to get it to “lock.” You’ve probably heard the term “lock to lock.” It also determines the “twitchiness” of the steering in the vehicle.
With a mechanical steering system, you get one ratio. You have to design around that ratio. If it’s a sports car, it’s going to have twitchy steering. If it’s a minivan, twitchy steering is just going to be annoying – especially on the highway.
Steer-by-wire systems are like throttle-by-wire systems in that the mechanical linkage between the steering wheel and the actual gear down by the wheels is removed. Instead, the steering column connects to sensors that then feed information to a computer about where you want to go. If there’s ever a catastrophic failure of the system, there’s a clutch that will reconnect you to the steering gear for manual control. Very clever.
That doesn’t necessarily make the steering inherently safer in any way, but it does open up the possibility for electronic add-on systems that could. It also gives the driver precise control over how the car is moved. Steering ratios are also a moot point as they can be electronically controlled and adjusted now.
So, if you’re feeling a little ambitious on a back country road, you can switch on a “sport mode” and have at it. On the highway, you can switch back to lazy driver mode so you don’t have to worry about the vehicle responding to 1cm of movement.
The New Magic
It’s no longer a comparison of Q50 vs G37 when it comes to handling anymore. The new Q50, for example, comes with one of these new-fangled electronic steering units, and potentially 500+ horsepower.
So, going forward, expect to see those horsepower and torque numbers rise as manufacturers figure out how to give you better control over your vehicle, and make it safer for you to zoom around. It means more choice, faster vehicles, more pulling power, more towing capacity, and potentially safer steering systems. Who wouldn’t want that?
Robert Navarro is an enthusiastic car connoisseur. After years of research and tracking trends and innovations, he greatly enjoys blogging about all things cars.
Categories: Gear Grinding