I know the principles behind ABS but, how does Traction control work, Thoppa ?
Hi,
I'm not too sure how it works exactly - I always assumed an ABS/TCS system measured the rotational speeds of the front and rear to detect if the front or rear is either locking up (ABS) or the rear was spinning too fast (TCS). ABS would then modulate braking pressure by pulsing it and TCS would lower engine torque to reduce any difference between front and rear rotation speeds. Because scooters are usually cable-pull throttles and single-cylinder engines, I assume that engine torque is lowered by retarding the ignition - so ABS can be used to measure wheel speeds for the TCS, and TCS controls slip/spin by retarding ignition.
I even find it hard to write that clearly! I hope it makes sense :-)
Bosch say in their documentation about the 9.1 system (
http://www.bosch.co.jp/tms2015/en/products/pdf/2WP_ProductDataSheet_ABS9_base_plus_EN_lowres_20151030.pdf) that their TCS can be added to their ABS, however, they are quite vague and don't give any technical details so I don't know for sure how it works - I assume it's much the same thing on the front and rear - a disc/sensor combo that create a large number of pulses every rotation - plus the TCS has to be integrated into the scooter's ignition (& fuel injection, etc?) systems so it can lower engine torque output - so I guess that is software added into the scooter's ECU but maybe it works some other way to control the engine. Does it need a ride-by-wire throttle or just a throttle position sensor or....? how about a torque sensor or calculation? I dunno. I guess that, as a basic system, it just needs to be able to lower the engine output until the rear wheel is turning at the same speed as the front but I don't know how it does it. Ideally, it would be able to know when the tire is experiencing high torque (gear, throttle, engine speed, wheel speed) and instantly detect a sudden spike suggesting a spinning rear is starting and cut it even before the spike had any real effect.
This is their ABS page :
https://www.bosch-mobility-solutions.com/en/products-and-services/two-wheeler-and-powersports/riding-safety-systems/motorcycle-abs/and motorcycle stability control page:
https://www.bosch-mobility-solutions.com/en/products-and-services/two-wheeler-and-powersports/riding-safety-systems/motorcycle-stability-control/I'm not the only one who has noticed how vague the manufacturers are about their technology. Here's an article on TCS that suggests different companies do it different-yet-similar ways and that no-one is giving up the recipe of their secret sauce. The article is a little out of date as many bikes now have six-axis inertia measurements so they have cornering abs, tcs, wheelie control, launch control, off-road and hooligan settings... you name it.
https://www.motorcycle.com/how-to/traction-control-explained-91272.htmlI'm old enough to remember setting the points, and then how wonderful electronic ignition was... and I loved it when fuel injection became better than a carb.... but now there's bluetooth-enabled speedos with smartphone apps for I don't know what. I dislike this trend but a bike with a six-axis imu does sound like a good idea - not idiot proof exactly but maybe clumsy proof - something I'd appreciate :-)
