KTM’s launch control secrets
How KTM’s 790 gets its power down so fast
KTM’s 790 Duke is the first middleweight naked with launch control – an automated system that, in theory, enables you to make a perfect getaway from the lights every time. GP bikes have been using it for years and we first saw it on road bikes with Aprilia’s RSV4 in 2011. But how exactly does it work?
“When you activate launch control mode, an algorithm uses the ride-by-wire throttle to hold the bike’s engine at maximum torque to provide the best drive,” explains Gerald Matschl, KTM’s Vice President for R&D. “When you perform a launch manually, you open the throttle just a little bit and then attempt to increase the power as you start moving and get the clutch engaged. Launch control keeps it at the best torque level for drive, and automatically opens the throttle according to what the bike’s sensors are telling it, therefore allowing the rider to focus purely on the clutch.”
With modern bikes containing a dazzling array of sensors, it comes as no surprise that launch control uses many of them – although not in the way you might assume.
“The bike uses the wheel speed sensors to calculate whether the front wheel is in the air, rather than use the IMU (Inertial Measurement Unit – or lean angle sensor) to calculate this. It looks for a variation in wheel speed, which, in a wheelie, is the front wheel slowing when the rear is accelerating, and then uses the IMU’s data to identify which way the wheel is going – up or down,” said Matschl. “If the wheel is going up, the launch control algorithm alters the throttle’s position to reduce torque. If it is heading downwards, it increases drive. It is very sensitive and allows a small power wheelie but not a big one that would compromise acceleration.”
While you might assume the IMU would control the angle of the wheelie, there are so many factors influencing the angle of the bike (suspension compression, angle of the road, etc) Matschl says it is better to use the ‘basic data’ supplied by the wheel speed sensors rather than rely upon anything more complicated than that. Obviously, a good launch also relies very much upon grip, so the bike’s traction control is activated during the launch at a pre-set level, and the launch control is automatically deactivated if the throttle is closed, a certain lean angle is achieved (meaning you’ve reached the first corner on a track/road) or you change up from third gear as the bike will no longer wheelie. Clever stuff.
‘Launch control delivers optimum torque’