Friday, February 26, 2010
Actually, the medal ceremony for women's hockey was very nice, as the mostly Canadian crowd changed USA! USA! after the American team was awarded the silver medal. It was generous, considering that the Canadians had been beaten in men's hockey by the U.S.
Thursday, February 25, 2010
Gilbert's testing discovered a hole in Toyota's diagnostics for their ETC system. To fool the system, he had to induce a highly unlikely failure. Toyota's system uses two pedal position sensors, which are separated by several centimeters, which have signal wires coming out on a common harness. Gilbert shorted the signal wires of the two sensors together through a resistor. By carefully choosing the resistor, he was able to find a short combination which the Toyota diagnostics did not detect. However, a short alone was not enough to cause unintended acceleration. To do that, Gilbert had to take the shorted wires, and then add another connection, to the power wire on the harness. When both sensor signal lines were shorted to the power line, then the throttle opened because the large voltage was interpreted as a command from the pedal. Because the two signals were within range of one another, the diagnostics didn't find it.
To induce this purely electronic unintended acceleration event, Gilbert had to induce two faults into the system. In the business, this is called a multi-point failure. It is similar to saying, "what if your gas tank was leaking and your wheel fell off, creating sparks". Because the sensors are separated in the throttle pedal housing, the only feasible way for this failure to occur, in my opinion, is for the wiring harness to be cut or frayed such that the signal wires are exposed, and electrically shorted, but not cut through.
Toyota hired respected engineering consulting house Exponent to do an outside check of their ETC fault robustness. The full report is here. Exponent bought several different Toyota vehicles, spliced into the ETC wiring harness, and inserted various types of faults, using engineering data provided by Toyota. All of the faults that Exponent inserted were quickly detected by Toyota's system. The difference in methodology from Gilbert's testing was that Exponent limited their faults to the more likely type, single-point failures, where a single wire or signal was compromised.
In short, Gilbert proved that by manipulating the system just so, he could break it. But his failure mode is not something that is remotely likely to occur in the real world. Gilbert produced what Safety Research Strategies, ABC News, and some congress members wanted: a dramatic demonstration. But he didn't find a smoking gun.
Wednesday, February 24, 2010
For now, I'd like to take a few lines to defend ETC in concept.
ETC has some significant advantages over mechanical throttle linkages.
- Fuel economy: actual throttle flow can be optimized based on operating conditions, and pedal position is used to infer driver intent. For example, someone with a shaky foot can be "smoothed out".
- Mechanical simplicity, weight, and cost: Using ETC means you can get rid of the idle air control valve, throttle cable, and cruise control actuator. Fewer things to break.
- Robustness: ETC systems have built in algorithms for unusual conditions. For example, the throttle plate can be shaken very quickly by the motor, as an "ice breaker", if the throttle plate is iced. There are no cables to bind up or corrode, no exposed return springs to break. The system has independent CPUs which monitor the throttle plate position and pedal position 100s of times a second, with fail-safe algorithms to shut the thing down if something unexpected happens. ETC has redundant sensors, which are used to check that the information coming into the ECUs is reliable and self-consistent. In a mechanical throttle system, the only failsafe is the driver's foot--if the thing is stuck, you pump it and pray it gets unstuck.
Trial lawyers try to sow FUD (Fear, Uncertainty, Doubt) about "complex electronic systems", and throw out scary "what if" scenarios, to try to win cases and big money. But engineers know that complex systems are designed, tested, and validated over many years before being released into production, and are tested for every conceivable failure. ETC systems must be qualified under a range of temperatures and wide band electromagnetic interference testing. Failure modes, such as cut wires, broken sensors, damaged actuators, etc. are all tested using a process called FMEA (failure mode effects analysis). FMEA was designed by NASA as a way to think through a system's reliabilty to pin down possible ways it could break; then tests are designed to validate the system under those conditions.
Is it possible that Toyota screwed up the FMEA, or cut corners, and has a dangerous-but-rare condition with their ETC system? It is possible. But given the excellence of Toyota's engineering, I would be surprised.
Tuesday, February 23, 2010
The reason that you only have one chance to brake a car which is experiencing a stuck throttle or unintended acceleration is that at wide-open-throttle, the engine is not generating any manifold vacuum. Without manifold vacuum, on most cars, the hydraulic brake booster will ingest air as the brakes are applied. Pumping the brakes will fill the booster very quickly. Without vacuum, the brake pedal will be very hard, and it will require a huge amount of brake pedal force to stop the car.
"If I would have done that on a Buick or a Honda... it would have set a DTC or code".
Monday, February 22, 2010
There is a lot chatter and ink flying about how the U.S. is beating Canada in the winter Olympics medal count.
But not really.
Canada is outplaying us if you normalize the data. Who cares about total medal counts? Better measures are in residents/medal and GPD/medal.
Let's compare some countries using Wikipedia's demographic information and current medal count:
U.S.A: 310,000,000 people, GDP $14,400,000,000,000, 24 medals, 7.7E-8 Medals/Resident, 1.6E-12 Medals/$ GDP
Germany: 80,000,000 people, GDP $2,900,000,000,000, 18 medals, 2.3E-7 Medals/Resident, 6.2E-12 Medals/$ GDP
Norway: 4,800,000 people, GDP $257,000,000,000, 12 medals, 2.5E-6 Medals/Resident, 4.7E-11 Medals/$GDP
Canada: 34,000,000 people, GDP $1,300,000,000,000, 9 medals, 2.6E-7 Medals/Resident, 6.9E-12 Medals/$GDP
Slovenia: 2,050,000 people, GDP $54,600,000,000, 3 medals, 1.5E-6 Medals/Resident, 5.5E-11 Medals/$GDP
Per capita and per $ GPD, Canada is clearing beating the U.S. They are winning about 3.4x the number of medals per resident, and 4.3x the number of medals per $ of GDP.
But Norway is really cleaning up. It is winning medals at a rate 32x the U.S., per capita, and 30x the U.S. rate per $ of GDP.
Friday, February 19, 2010
My answer: something like a Mustang GT, or Chevrolet Camaro, or Dodge Challenger, running a V8. Even a Pontiac G8.
Because when NHTSA, EPA, and CARB's CO2 and fuel economy regulations kick in full bore, only rich guys will be able to afford a good fashioned American V8. Naturally aspirated, big displacement, big torque.
Sunday, February 14, 2010
Friday, February 12, 2010
The new (and hopefully correct) GPS location of the prize is N42*33.547, W83*12.596
Also, more hints about where it is:
Follow the right side of the field, to where you can see the power transformer.
Follow the path until it comes to a "T".
The prize is hidden behind a large fallen log about 20" off of the trail from the "T".
Thursday, February 11, 2010
Here's a hint: the cache is within a 15' radius of the T shaped intersection which forms the last waypoint. It isn't buried, but it is not in "plain view" from the trail.
Monday, February 08, 2010
If somehow, inexplicably, you do win tomorrow, promise us that you'll moon the other racers and scream, "Suck it, losers!"
(Laughs.) I think it'd be really funny if I started winning all the time and became really annoyingly girly and put on lipstick before every race and started wearing heels and stuff like that. I probably can't back any of this up, because I'd feel really uncomfortable and self-conscious and I'd never follow through. But it's a funny idea.I like her more after reading the interview... her whole bikini-girl-racer image, and the stupid dot com commercials she is doing make her seem very superficial. The interview shows a much more interesting person.
Really, the only way to sanely drive the Legacy Limited is with the paddle shifters. If you don't use them and leave the car in automatic mode, it's confusing and uncomfortable.
When you launch the vehicle, its revs tend to jump and then stay too high. Because the shift points are gone, something feels off -- though the Legacy is performing exactly the way it was designed. The CVT searches for the most efficient engine speed to produce the power it needs -- this is one of the reasons CVTs provide better gas mileage.
Sunday, February 07, 2010
Wednesday, February 03, 2010
What WR doesn't bother telling us is that the Tango is not really a production vehicle. It is sold as a kit. After you plunk down your $108,000, you get a shipment of a rolling chassis. Followed later by a shipment of missing parts that you can bolt on yourself, or have one of the Commuter Cars guys come out and install for you.
And if you live outside of the Spokane, WA area, where do you go if you need your Tango serviced? I assume you will have to have a Commuter Cars rep fly out to you.
There is currently one street legal, mass produced, electric-only vehicle in the U.S., and that is the Tesla Roadster. Everything else is, at this point, either vapor-ware or a toy.
LaHood needs to be more careful what he says--he could cause some real public relations problems, for himself and for Toyota.
While sticky throttle pedals are a serious problem, the failure mode is rare, and completely controllable if the driver pays attention and keeps a cool head.
1) Press brakes firmly
2) Put the gear selector in N
3) Pull over
If 2) is a problem for some reason, you can turn off the motor.
Tuesday, February 02, 2010
After consuming "unknown quantities of alcohol", he strapped on a motorcycle muffler which he had stuffed full of gunpowder, match-heads, and gasoline. He also put on a motorcycle helmet and a cape. Then he had a friend light his fuse, and started down the hill on a plastic orange sled, no doubt after saying something like "Hey guys! Watch this!"
It did not end well. But, he didn't quite make it onto the Darwin Awards--he's in the hospital.
Monday, February 01, 2010
The toothy thing is a pedal feedback mechanism which uses friction to give the pedal a certain amount of resistance at the end of its travel.
What Toyota is doing is putting a shim in behind the pedal arm, to limit its travel. Which means that unless they reprogram their ECU to interpret the new position as WOT (wide open throttle), customers won't ever be able to get to WOT--instead they'll top out at 97% or whatever the new maximum travel point corresponds to.
So in addition to installing "precision cut steel", I would expect Toyota to also have to spend a few minutes on each car to reprogram the throttle pedal calibration curves. Unless, of course, the extra few percent of travel isn't needed.