Kawasaki Ignition Management System (Kims)
Is it a true traction-control system?
When the first tidbits of news began trickling out about the '08 Kawasaki ZX-10R having an ignition management system that "curtails sudden spikes in engine speed for improved rider control," the immediate assumption from the public was "traction control." After all, traction control has been the buzzword in both MotoGP and World Superbike for the past couple of years, enabling racers to produce corner-exit drives and maintain a pace over the course of a race that normally would be very difficult. It would surely only be a matter of time before this rider-aid technology filtered down to production bikes. But is the Kawasaki Ignition Management System (KIMS) really a traction-control system?
In order to determine whether there is actual wheelspin occurring, you obviously need to be able to detect if one wheel is rotating faster than the other. The usual method of achieving this is with wheel-speed sensors. Because antilock braking systems require the same wheel-speed data, it was an easy transition to develop traction control (followed by "vehicle stability systems") and make them standard equipment on most automobiles. Motorcycles-especially sportbikes-haven't adopted ABS as quickly as cars, however, so the hardware and software isn't already there.
Without wheel-speed sensors, the only other reliable method of detecting wheelspin is to monitor rpm and determine if the rate of change during acceleration is excessive. With an automobile's mostly flat-profile tires this would be an easy task. The drastically different profile of a motorcycle tire, however, makes determining if a rapid rise in rpm is due to wheelspin or a sudden lean-angle change (moving from the center's taller circumference to the edge's much smaller one, effectively changing gearing) a far more difficult job.
Complicating matters is that most racers want the ability to steer with the rear tire in certain situations by intentionally spinning it. This requires a host of other parameters besides rpm to be monitored, including throttle position, gear selection and speed, among others. Some of the more sophisticated systems in MotoGP have internal gyros to measure lean angle, as well as GPS to allow programming for different corners on the racetrack. All this requires incredibly complicated software and powerful processors to crunch the information and determine whether to intervene, at what point and to what degree.
The KIMS uses this basic method of monitoring the engine rpm's rate of change. By keeping track of other parameters such as throttle position, gear selection, air/engine-coolant temps and oxygen levels in the exhaust (and doing all this every 0.02 seconds), the KIMS intervenes by retarding ignition timing when it senses an rpm spike. More than 500 different situation maps are stored in the ZX-10R's ECU, allowing a huge variety of options for the KIMS to use.
The caveat, however, is that it will only intervene at smaller throttle and lower rpm settings; big handfuls of throttle at higher rpm (such as when a rider wants to intentionally spin the rear tire) will override the system. This means that not only will the KIMS rarely intrude upon a rider on the track, it's also not a failsafe that will keep ham-fisted riders from ending up on their heads. We found the Kawasaki would easily spin up the sticky Pirelli Diablo Supercorsa DOT race rubber on Losail's superb pavement if provoked. "We want expert riders to have the freedom to ride the ZX-10R without electronics intruding on their technique," says ZX-10R project leader Yasuhisa Okabe.
So is the KIMS a real form of traction control? In a way, yes; we can see it helping with wet-weather traction on the street, keeping the rear tire from spinning unintentionally at slower speeds. Whether it will actually accomplish this will have to wait until we get our hands on a test unit back in the States, as we weren't able to engage it on the high-speed tarmac of Losail. But as an actual form of traction control in any type of performance sense, the KIMS doesn't fit the bill.
A plethora of parts are included in the race kit available from Kawasaki dealers for those interested in competing with their ZX-10R.
Will the race-kit ECU turn it into a full traction-control system? When we asked Okabe-san, he replied that while the race kit ECU would "allow an expansion of options available," the KIMS will still be nonadjustable and function basically the same way. We asked him when we might see real-time traction control on production sportbikes. His cagey reply was, "Maybe in the near future. ABS first . . . then maybe traction control soon after."