This could be very dangerous: throttle cable

[kwren]

Sorry, forgot the back!

Keith

[kwren]

..........................................

[Trevor]

Originally Posted by kwren

..........................................

You selfishly waste space, like no other person posting. Give us a break.

[b3lha]

Originally Posted by Trevor

As a result of the issues involved, and the fact that I have been deeply involved with control systems, the new “fly by wire” set ups worry me. Have they got it right? Is anyone here aware of the details?

The recent model Subaru drive-by-wire cars have TWO potentiometers on the accel pedal, operating in opposite directions. The ECU program contains logic to check that the signals are consistent with each other and will throw an error code if either potentiometer gives trouble.

The throttle valve itself also has two potentiometers and the same principle applies. The only real possibility of trouble comes if the pedal becomes mechanically stuck - the problem Toyota are having.

The DBW system has big advantages on turbo-charged cars. The ECU can regulate the boost pressure using both the throttle and the wastegate. As I understand it, at 50% accelerator, it is more efficient for the ECU to open the throttle 100% and regulate the airflow using the wastegate solenoid than it is to have the turbo blowing hard into a half-open throttle.

All things considered, DBW is much better than the old cable system.

[Trevor]

Thank you Phil,

I suggested interlocking and limit switches which was decried. I have just read the following within a news item:-

Dennis Virag, president of the Automotive Consulting Group, said Toyota has erred in not adopting a brake override system for all its cars - one that shuts off the fuel supply to the engine if the brakes are engaged and the accelerator is down.

In my area of expertise, when safety is involved, interlocking is a basic requirement. It has always been clear to me that those designing automotive electrical systems, are negligent in many, many areas, hence my scepticism.

[kwren]

speaking of wasted space...

Keith

[Hondasucks]

Originally Posted by b3lha

The recent model Subaru drive-by-wire cars have TWO potentiometers on the accel pedal, operating in opposite directions. The ECU program contains logic to check that the signals are consistent with each other and will throw an error code if either potentiometer gives trouble.

I haven't looked at the Subaru throttle sensors, but the Toyota pedals are actually a hall effect sensor, the pedal part contains a magnet that gets progressively closer to the pickup sensor in the stationary part of the pedal. The moving part has two "wedges" and the data list on the scan tool shows two sensors, however they don't move in opposite directions like the Subaru does.

The problem with the pedals is the return spring not returning the pedal to idle when released, not sticking wide open (That is what happens when they hang up on the floor mats, but what causes that is people stacking mats, etc) The "Fix" is adding a shim to the pedal to increase the spring tension.

[Trevor]

Originally Posted by kwren

speaking of wasted space...

Keith

Rattle your dags Keith.

Kia ora Hondasucks,

Worthwhile information and very interesting.

The automotive lot are relying on fitting two of a kind, presuming that both will not fail. This would not be unacceptable within my field. An interlocking arrangement is much more secure, on many counts.

Cheers, Trevor.

To waste more space, --- another great grandson has just arrived.

[b3lha]

Originally Posted by Trevor

This would not be unacceptable within my field

If one negative is good, then two must surely be better.

Originally Posted by Trevor

another great grandson has just arrived.

Congratulations on the new baby. Hope everything went well.

[kwren]

Originally Posted by Trevor

Rattle your dags Keith.

Kia ora Hondasucks,


Cheers, Trevor.

To waste more space, --- another great grandson has just arrived.

Congratulations on the new grandson!

Back to reality!

And in Japan on Wednesday, authorities told Toyota to investigate reports of faulty brakes on its high-profile Prius hybrid car as federal safety regulators in the U.S. began a broader investigation into Toyota's electronic systems.

The Prius also came under scrutiny this week after Apple co-founder Steve Wozniak claimed that he had been experiencing sudden acceleration in his 2010 Prius because of an alleged "software" glitch.

Wozniak's claim, valid or not, underscores questions about Toyota's electronic systems raised by less-famous consumers. In a well-documented case detailed in a petition to the National Highway Transportation Safety Administration (NHTSA), Jordan Ziprin claims that, in 2005, when backing out of a driveway near his home in Phoenix, his 2002 Toyota Camry XLE suddenly accelerated and slammed into a utility box.

He did not have his foot on the gas pedal and the car accelerated under its own accord, Ziprin claims. This appears to be an electronic glitch: an issue very different from the mechanical defects cited in the accelerator pedal cases that Toyota is trying to address now with its recall.

Hello???

Keith

[kwren]

Pay attention... They aren't messing with the software because they don't have anything else to do.

Keith

[b3lha]

I have heard about a case where a driver, after an accident, claimed that his car had suddenly accelerated of it's own accord.

But the vehicle manufacturer was able to produce a detailed telemetry log from a hidden black box recorder on the car that showed the driver had been driving excessively fast for the whole journey.

Some manufacturers are fitting "black boxes" to high-performance cars so they can rebut warranty claims when the car has been tuned or abused. Some people adjust the ECU boost maps to get more power. If the engine blows up as a result, they reflash it back to stock and try to claim on the warranty.

[1986nate]

Originally Posted by b3lha

Some manufacturers are fitting "black boxes" to high-performance cars so they can rebut warranty claims when the car has been tuned or abused. Some people adjust the ECU boost maps to get more power. If the engine blows up as a result, they reflash it back to stock and try to claim on the warranty.

It's actually every car that has an airbag system has this feature. Whenever airbags are deployed, the police are able to get computer data that records throttle pressure, brake pressure, speed, and 1 or 2 other things I believe. It records 5 seconds that is constantly being overwritten until the airbags are deployed and at that point it locks in the data. It has been used on more than one occasion to convict people of vehicular manslaughter due to wreckless driving for people that were speeding excessively.

[Hondasucks]

Originally Posted by 1986nate

It's actually every car that has an airbag system has this feature. Whenever airbags are deployed, the police are able to get computer data that records throttle pressure, brake pressure, speed, and 1 or 2 other things I believe. It records 5 seconds that is constantly being overwritten until the airbags are deployed and at that point it locks in the data. It has been used on more than one occasion to convict people of vehicular manslaughter due to wreckless driving for people that were speeding excessively.

Weird, I've never heard of this, nor have I ever seen anything to this effect show up in the scan tool at work, or in any of my training stuff... Wouldn't surprise me though. As for the people with mysterious acceleration on their Toyotas, I'm sure a chunk of it is just people blowing smoke trying to get $ out of Toyota. They issued the recalls to take care of their customers. The defect reports were issued to the government voluntarily; they wanted to rectify the situation before more problems occurred and the government forced THEM to issue a recall. There have been less than a dozen cases of the gas pedal sticking, and the floor mat interference has been tied to people either stacking the all weather floor mat on top of the carpeted one, or to improperly secured and/or stacked aftermarket floor mats. The problem with the Prius is when the system switches from regenerative braking to hydraulic braking (which is less often than you think, I've worked on Priuses with 130k on them with ~75% of the brake pads left) it can cause the pedal travel to increase noticeably under certain conditions, but doesn't actually affect the stopping ability of the vehicle.

[1986nate]

There is only one company that makes a tool/reader that is able to read it and believe me, they aren't cheap since they have a monopoly on it since they were the ones who wrote the code and designed this feature. A dealership would have no reason to invest in the reader for this. Only law enforcement or insurance companies would have use for this.
There was a special on MSNBC I think and it was about how much all technology can be tracing what you do, whether it be something as obvious as GPS, or your printers, digital cameras, etc all have a form of tracking exactly which camera a picture was taken on or exactly which computer a piece of paper was printed from or exactly which disc drive a cd/dvd was burned from all tracked by putting the model number and serial number embedded in some way. And one of the segments was about the Airbag computer is literally a black box on cars and it dates back to ANY vehicle ever equipped with an airbag computer.
Kinda scary because they could easily write the program to store the data for even longer and then insurance companies could use that info to see how you drive and what your rates should be.

old article but has some info on the system... if you want to find out more, just "airbag black box"
http://www.consumeraffairs.com/news0...es_states.html

here's a better one....
http://www.theairbagblog.com/how-air...ata-recording/