By now, most people will know about Mazda’s SKYACTIV technology that is present in all its models. Though some may think it refers to just the powertrain, SKYACTIV Technology is actually much wider in scope, encompassing all aspects of the vehicle’s design and engineering. For instance, there’s SKYACTIV-DRIVE (transmission), SKYACTIV-BODY (body structure), and SKYACTIV CHASSIS (chassis). For the domestic market, there’s also SKYACTIV-HYBRID technology in a variant of the Mazda3.
Being related to each other, the various elements in the SKYACTIV Technology are now being integrated to enhance vehicle handling. This has led to a new generation of vehicle motion control technologies which are unified under SKYACTIV-VEHICLE DYNAMICS. With integrated control of the engine, transmission, chassis and body, Mazda engineers are able to enhance the car’s ‘Jinba Ittai’ feel – that sense of ‘connectedness’ between car and driver.
The first technology in the SKYACTIV-VEHICLE DYNAMICS series is GVC and this is an approach whereby engine torque is varied to influence the dynamics of the car. It is the world’s first control system to vary engine torque in response to steering inputs in order to provide integrated control of lateral and longitudinal acceleration forces; until now, lateral and longitudinal acceleration (G) forces have been controlled separately. This optimizes the vertical load on each wheel for smooth and efficient vehicle motion. By optimizing the load on each tyre brings the movements of the car more in line with the driver’s intentions, reducing the need for steering corrections, including many that are made unconsciously.
GVC maximizes grip by focusing on the vertical load on the tyres. 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 tyre 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 tyres, improving vehicle responsiveness and stability according to the driver’s intentions.
It sounds complicated and certainly, without a computer, all the actions would not be possible because they must be done at lightning speed. So the computer has to be able to process numerous streams of data from sensors continuously and send signals to the engine to adjust its output. What’s important is that the driver does not need to do anything and just enjoy the drive – which is what Mazda aims to provide.
GVC is not just fast and sporty drivers and actually has usefulness in everyday driving conditions. In fact, Mazda says it benefits drivers of all skill levels in a wide range of situations: from low-speed urban motoring to highway driving, winding roads, and even emergency manoeuvres. In addition, GVC significantly improves handling and stability on wet, snowy and unpaved roads and in such conditions, its benefits are at their best.
GVC acts smoothly so that it is virtually unnoticeable (in fact, many people won’t realise it is at work!). The reaction rate and amount 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. So the driver will still have a natural driving feel but Mazda says that there is quicker and more precise control than is possible for a human driver.
Another benefit which even passengers will appreciate is less swaying of the head and body during cornering. This is something which may not be apparent but as a car is driven over many corners, the head and body will move and although the discomfort may not be noticed, there will be a degree of fatigue which builds up.
GVC can reduce such stress on the body caused by such fatigue because the minor steering corrections that cause the body sway are greatly reduced, even at low speeds. And when you consider how many corners you will go through on even a short drive to the nearby grocery store, that’s a lot of stress the body will experience.
So on long-distance trips, a driver will have less fatigue and that not only makes the driving more pleasurable but also safer. It’s something not immediately apparent but will make driving a Mazda feel different in a way that the driver might not be able to understand.
In addition, it is a highly versatile system adaptable to vehicles of any class and drive type. Being a software control system, there is no weight increase due to the use of additional hardware components. The only requirements are a SKYACTIV engine, which allows precise control over torque output, and a SKYACTIV chassis.
If you are in the Klang Valley this long weekend (April 28 – May 1), you can experience GVC at the ‘Let’s Celebrate Driving’ event organised by Bermaz Motor at the Setia City Convention Centre in Setia Alam, Selangor. There’s also a display of the latest Mazda models at the Setia City Mall which is near the convention centre.