SALINAS, California—Ever heard of “equilibrioception”? Or “minimum jerk theory”? That last one might sound like you’re cutting down your Facebook friends list, but in reality, these things helped Mazda develop its latest technology, G-Vectoring Control (GVC).
It’ll be gradually rolled out across most of Mazda’s models, starting with the Mazda3 and Mazda6. But what’s really unusual is that even if you buy a Mazda that has it, it’s unlikely that you’ll even realize it.
It makes such a subtle difference that I was only able to discern it by driving a specially-equipped model where it could be turned on or off (it’ll be a default on production models, without a defeat switch). You just have the sensation of a car that handles really well.
The engineers extensively studied the human body during the process. Equilibrioception is your sense of balance, while minimum jerk theory is the fact that moving smoothly, such as when walking, is the most efficient and comfortable way.
In a vehicle, other than the fun of an occasional racetrack ride-along, most people are happiest when their heads are upright and they’re not being jostled around. By smoothing out the motion when the car changes direction, GVC provides a more comfortable ride.
But it isn’t only about passengers. That’s actually more of a side benefit, since it’s really about improving grip and steering response.
How it works seems deceptively simple. When you initially turn the steering wheel, GVC reduces the engine’s torque. It’s so slight and quick that it’s impossible to detect, but that momentary deceleration transfers just enough weight forward onto the front tires – about five kilograms to each one – to better their grip and improve the steering response. As soon as you hold the wheel steady, the engine returns to normal.
The result is that, while you can’t feel exactly what it’s doing, it takes less effort to keep the car under control. In any vehicle, you’re continually making little steering corrections to keep the car straight, especially on rougher roads. With GVC, you don’t make as many, and the ones you do are smaller.
Even so, it’s hardly noticeable, since you correct your steering so automatically that you seldom realize you’re doing it. It was more obvious from the rear seat, where passengers are jostled more by steering movement along the car’s length: with GVC on, the ride was smoother.
I most noticed what the car was doing on two courses, one water-soaked and the other loose gravel, where I had to make turns at 50 km/h. With GVC on, it was easier to keep the car tight in the curve and it better obeyed my steering input.
You can see in the video, taken on a dry course, that the difference is minimal (it’s more noticeable on the second turn).
It’s all done with software and needs no extra greasy bits. But it took eight years to develop, simply because everything has to happen so quickly and seamlessly. Braking was the obvious first choice for weight transfer, but even the fastest brake response produced a noticeable lag.
Engine management systems weren’t quick enough at the time, and torque vectoring – applying power to individual wheels rather than cutting it back – didn’t achieve what the engineers wanted.
Finally, because electric motors start and stop almost instantly, GVC was developed on an electric car. When Mazda began production of its new SkyActiv engines, which could handle the milliseconds of deceleration, it was able to proceed with a gasoline unit.
The roll-out across the lineup will be gradual because the system has to be dialled in for each vehicle’s weight, size, steering and suspension, and will be added as models are updated.
So why come out with something so subtle that most drivers will never even realize what the car is doing? Mazda says it’s simply an engineering improvement, just as if it adjusted damping rates or added different springs, which is why it can’t be defeated and why it probably won’t be advertised (plus it’s really too complicated to explain in a 30-second commercial).
Overall, it smooths out the ride, reduces the need for wheel input, and on slippery surfaces, it reduces the slip angle for better control. It’s not just subjective feel: the engineers even took electromyographs of passengers’ necks to see how much they were jostled.
It’s also the first of a series of technologies, all yet to be revealed, that will come under the name of SkyActiv Vehicle Dynamics. It’s not a huge difference, but it’s there, and that’s exactly what Mazda intended.