EE Times Under The Hood - October 8, 2007 - (Page 12) under the hood: FEATURE <<6 are stunningly fast. As a point of reference, the current 800cc GP machines create about twice the horsepower of the 1.5-liter Prius gas engine (see the Prius teardown at www.techonline.com/underthehood, search article ID: 199100168) in a package weighing just 11 percent of the car. Closer to the breed, MotoGP bikes have a power/weight ratio about three times that of my own quite-competent 600cc production Kawasaki sport bike. Beyond the fantastic mechanical engineering, custom fabrication and state-of-the-art tires in GP machines, electronics are instrumental to (horse) power management, and it is these electronics that were the focus of my discussion with Casonato. Passing the speed gene In some respects, the GP motorcycle class pushes the performance envelope by what might seem an absurdly small measure. Fastest Laguna Seca lap times for GP bikes were about 1 min. 22 sec, just two to three seconds quicker than the best from the modified (but still production-based) 1,000cc AMA Superbike motorcycles that raced the same weekend. Given trickle-down effects from GP, it could be argued that Superbikes wouldn’t come as close without the benefits derived from prototype racing. Both race classes use electronics extensively to tune for performance and manageable power delivery, but the GP bikes remain the more potent machines, and electronics—along with overall budget—get stepped up accordingly, all to shave off even a few seconds. On-board electronics tackle both data collection and system management. According to Casonato, “Much of the time spent optimizing happens on the dyno” where track-based data and real-time feedback are used to improve the engine control unit (ECU) and associated systems. As with any modern car, the ZX-RR’s ECU maintains proper gas-air mixtures, adjusting fuel injection and controlling spark timing and profile. In the 18,000rpm, 200-mph environment of GP, however, the ECU and associated software are brought to the limits of speed, sophistication and fine-tuning. Of course, racing doesn’t happen on a dyno, so track-specific improvements are a critical overlay to time spent in the shop. Casonato described the engineering as “one of first controlling in anticipation of the rider’s actions” and second, responding to departures from controlled performance. This likely means power delivery may be adjusted up or down depending on the bike’s immediate location on a specific track. Opening up available power on long straights and closing down performance for sharp, challenging corners helps cut lap times while giving the rider a safety net when the limits of tire adhesion are being stretched. If and when things get out of shape beyond that first-order control envelope, electronics are designed to take further steps to rein things in. There is GPS capability on the ZX-RR, which seems the most straightforward method to pin bike location for the purpose of control mapping. Location sensing is just the start of the myriad elec- www.eetimes.com • www.techonline.com ONLINE For more about these systems, see the online version of this feature at www.techonline.com/underthehood tronics systems featured on the ZX-RR, from the engine control unit to the data display to remote communications. Efficiency still critical Optimal power delivery and controlled riding are key end goals for the ECU and its numerous inputs, but fuel mileage is also important. Since there are no pit stops, riders and machines must make the 21 liters of allowed gas last a full race. Accordingly, fuel economy is carefully managed. If you can’t make the last lap around the track, any lead earlier in the race is useless, and Casonato was quick to highlight the superior gas mileage of GP bikes over their larger-displacement Superbike “fly-by-wire.” Kawasaki is understandably secretive about details on the link between rider throttle input and actual engine manipulation. A rubberdamped potentiometer monitors throttle position, but throttle cables are clearly present. Given the money involved and the desire to gain an edge, engineering secrets are a reality here. No photographs of the many computer screens were allowed. Clearly, software, performance data and data analysis are a huge part of the search for a competitive edge. All the careful data forensics join with quick-thinking adjustments in this high-pressure environment, and the race for engineers and technicians happens in a well-equipped (and carpeted!) paddock along pit row. Kawasaki’s GP garage had no shortage of wirelessly connected computer systems, communications radios and flat-panel screens for staying in touch with one another. According to Theo Lockwood, engine development engineer for Kawasaki’s Superbike team, engineering efforts occurred in an environment where the rider, rather than the machine, still largely determines the outcome. Additionally, the designers ultimately were there to manage (but not necessarily design) systems whose purpose is to instill rider confidence. Man vs. electronics? Despite the engineering excellence, the migration of electronics into GP (or Superbike) racing is not without controversy. Teams want to win, but sometimes racers just want to race, and electronics can blunt the rider’s ragged-edge skills. The other side of the debate is that electronics make for a safer, more-controlled contest that is ultimately faster. Sliding, smoking tires may provide a better show, but they rarely lead to a faster race. While there have been calls for less-intrusive technologies and even outright bans on traction control, it is winning that matters; until enforceable rule changes mandate a dramatic shift, the electronics incursion into GP racing may be difficult to undo.■ 12 Electronic Engineering Times, TechOnline | October 8, 2007 http://www.eetimes.com http://www.techonline.com http://www.techonline.com/product/underthehood/202103635 http://www.techonline.com/underthehood http://www.techonline.com/underthehood
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