Ask the people who have experienced unintended acceleration in their cars what they think when a corporate spokesman says that it can’t happen. And in case you think these are isolated incidents, according to a Consumer Reports article from December 2009, 52 unintended acceleration complaints were reported to the National Highway Transportation Safety Administration (NHTSA) about Toyota products (Toyota and Infinity) and 36 complaints were lodged about Ford products produced in the 2007-08 model year. While these occurrences took place in automobiles, a quote about drive-by-wire used in motorcycles from the Bosch website (bosch-engineering.de/en/boschengineeringgmbh/newsspecials/drive_by_wire.aspx) is of particular interest: “Thanks to the use of fully-electronic engine control systems, motorcyclists now have complete control over their machines, too. To do this, existing automotive systems were adapted to motorbikes within the framework of our drive-by-wire motorcycle study. The first road-capable prototype is an Aprilia RSV 1000 R. In selecting the components we rely on Bosch components from the automotive sector, which are thus now available for the motorcycle market. The development of the electronically controlled throttle valve for motorbikes is yet another example of customer-specific, individual system adaptations of Bosch components for which Bosch Engineering GmbH is internationally known.”
So basically, what Bosch is saying here is that motorcycle “fully electronic control systems” are adapted from automotive systems. It is logical then to consider that any potential hardware failures and software programming errors that by some accounts have already occurred in automotive systems could also be potential problems in motorcycle systems.
...if he is not able to get the bike under control quickly, the rider is likely to crash.
Let’s examine another point that’s very important: the anomalies in the S1000RR engine management system that Mr. Acton described were not malfunctions. The loss of throttle control, the inability to accelerate when the bike was leaned, and the (unexpected) surge of power when it was partially righted is how the electronic engine and traction control management system for this bike are designed and programmed to work under those conditions. Oddly, in the review of the S1000RR, Mr. Acton did not seem alarmed by situation where control of the bike was apparently out of his hands, and he generally gave the bike a favorable review.
So here we have an example of an anomaly in the electronic engine control system when the bike is functioning properly. How about what happens when things do malfunction?
In some recent discussions with David Hough (author of the Proficient Motorcycling book series) on the issue of throttle control and electronic engine management, he relayed to me a situation where a previously owned Can-Am Spyder (with electronic throttle) had a re-occurring drivability problem: “I had some…electronic issues, one being that the engine would suddenly go into “limp-home” mode after about four hours on the freeway. I found that shutting off the main switch for a period of time would…allow the system to reboot, and then it would start and run normally. The error message on the dash showed “Check DPS Computer.’” DPS is Dynamic Power Steering—sort of a “mother” computer, and if a fault in any of the other systems occurred, the DPS computer would signal the Engine Management Computer to initiate a loss of power…I [later] discovered that the leaf spring on the brake pedal was not giving the appropriate “brake off” signal to the DPS computer. I did a little adjusting with needle-nose pliers, and solved the limp-home problem.”
As many know, limp-home mode is where an engine management system will limit speed and acceleration in order to prevent engine damage when a problem occurs. However, in this case, the limp-home mode activated on a freeway when the problem apparently had nothing to do with an engine malfunction. Here is a case where an electronic override system caused a motorcycle-based vehicle to suddenly slow down on a freeway while other traffic around the vehicle would normally be maintaining highway speeds. While this might make sense if the limp-home mode had been activated due to an engine problem, should it have been caused by a simple mechanical problem with a brake signal switch? Most would probably argue no.