Mazda introduces SKYACTIV-VEHICLE DYNAMICS control technologies; G-Vectoring Control uses engine to enhance chassis performance
14 July 2016
Mazda Motor Corporation is introducing SKYACTIV-VEHICLE DYNAMICS, a series of new-generation vehicle motion control technologies. The first in the series, G-Vectoring Control, will be introduced to all new-generation models starting with the updated Mazda Axela (known as Mazda3 outside Japan), which has just gone on sale in Japan. By adopting GVC, Mazda vehicles will exhibit even smoother transitions between G-forces in all driving scenarios.
Until now, lateral and longitudinal acceleration (G) forces have been controlled separately. GVC is the first technology to adjust engine torque in response to steering inputs in order to control these forces in a unified way and optimize the vertical loading of each tire to realize smooth and efficient vehicle behavior.
| Top: GVC conceptual diagram. Bottom: GVC control equation. Click to enlarge. |
The vehicle moves more precisely as the driver intends, reducing the need for steering corrections, many of which are performed unconsciously. The driver feels more at one with the vehicle and more confident because the car follows his or her intended line precisely.
Cumulative fatigue on long drives is reduced and smooth transitions between the G-forces acting on vehicle occupants reduce torso-sway, improving ride feel and passenger comfort. GVC also improves handling and stability on wet or snowy roads and the enhanced feeling of grip gives drivers peace of mind.
GVC mechanism. GVC maximizes tire performance by focusing on the vertical load on the tires. The moment the driver starts to turn the steering wheel, GVC controls engine drive torque to generate a deceleration G-force, thereby shifting load to the front wheels. This increases front-wheel tire grip, enhancing the vehicle’s turn-in responsiveness.
Thereafter, when the driver maintains a constant steering angle, GVC immediately recovers engine drive torque, which transfers load to the rear wheels, enhancing vehicle stability.
This series of load transfers extracts much more grip from the front and rear tires, improving vehicle responsiveness and stability according to the driver’s intentions.
| Correlation between steering angle and G-forces when cornering. Click to enlarge. |
Changes in the acceleration forces acting upon vehicle occupants are smoother, reducing torso sway and making for a more comfortable ride. In addition, GVC significantly improves handling and stability on wet, snowy and unpaved roads.
The degree of control is extremely subtle, with a reaction time from the moment the driver operates the steering wheel faster than a person can perceive, and the resulting deceleration force usually at or below 0.01 G. One of the key features of GVC is that it enhances a natural driving feel by offering quicker and more precise control than is possible for a human driver.
Mazda says that GVC will benefit all drivers of all skill levels in a wide range of situations: from low-speed urban commutes to highway driving, winding roads, and even emergency maneuvers. In addition, it is a highly versatile system adaptable to vehicles of any class and drive type. The only requirements are a SKYACTIV engine, which allows precise control over torque output, and a SKYACTIV chassis, which enables superior dynamic performance.
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