Sudden Unintended Acceleration

[whitex]

Possibly for some people, but I will live with that since we would only have creep mode on at home. I'm not bothered by the change in regen depending on the conditions, so I guess it is just a personal thing.

If you're worried now about creep accidentally causing an accident, imagine how worried you'd be if you didn't know when it would activate on you, say GPS glitched while you were at a light thinking it's at some parking lot you enabled it before. My SAS attempts to switch to high suspension on occasion when I drive near places where I raised it, one of them is on a highway which happens to be near a shipping strip mall - I always get the error message as high suspension is not allowed at highway speeds.

 

[whitex]

With this 2 pedal talk i'm confused. My Tesla will not move the car at all if I press brake and accelerator together. It beeps and gives error msg. "2 pedals pressed" So 2 pedals does not work unless of course you lift the brake pedal off

Correct. What I was talking about is if that safety software was to fail and power was applied to the motors, the brakes should still be stronger than the motors, so the car would not move.

 

[FlyF4]

With this 2 pedal talk i'm confused. My Tesla will not move the car at all if I press brake and accelerator together. It beeps and gives error msg. "2 pedals pressed" So 2 pedals does not work unless of course you lift the brake pedal off

You might be misunderstanding the 2-pedal driving as used by me a small percentage of other drivers. It is as you say in your last sentence. Thus, it doesn't mean having both feet on both pedals at the same time. It means to have the left foot close to the brake and when it is time to stop, to use the left foot on the brake and lift the right foot off the accelerator. Thus the right foot doesn't move left to right between the pedals as needed. Some people will claim reaction time is faster and some say slower. for me it is faster. You may find that some airplane pilots use 2 feet as they are used to doing in planes, yet some pilots will still use one foot when in a car. It's just a personal thing. I've been driving that way for 50 years. I personally would not recommend anyone start using a 2-foot method after driving with one foot. You might get confused.

 

[FlyF4]

I wonder if this vigilance is also a result of your aviation training and experience. I'm not a pilot, but I'm somewhat familiar with the aviation culture, and there are a number of concepts and themes from flight training that seem to be useful in driving, like verifying settings and controls and not trusting/assuming that they just work correctly. Any thoughts?

Bruce.

PS. Going further off topic, thank you for your service. The California ANG wing in my hometown used to fly the F-4D, and their departure path went over my high school...got very used to hearing those twin turbines passing overhead just after lunchtime.

Apologies to the thread for off topic. Yes sir, you hit the nail on the head. Even when in AP mode, I think of it as AP in a plane. I won't take eyes off of controls for very long. Technology can make mistakes just as humans do, yet typically fewer mistakes in most systems. Not saying pilots are better drivers. You might be surprised to know that in 50 years I have NEVER gotten a moving violation. Also not saying that pilots are necessarily safer drivers, it might be that we are more observant of the surroundings to see the cops in advance
Sorry you might be deaf due to F4 afterburners in your ears

OK, so back to the topic of how do we prevent the Tesla from hopping like a frog?

 

[FlyF4]

Correct. What I was talking about is if that safety software was to fail and power was applied to the motors, the brakes should still be stronger than the motors, so the car would not move.

yes, and it appears from drawings that the brake pedal removes power from the motors directly even outside of software.

 

[Don85D]

It's generally true that brakes have more stopping HP than the engine has to make the car move, however there is a surprise factor that needs to be considered. I have been in vehicles with unintended acceleration and the initial surprise drives you back into the seat reducing the foot pressure on the brake. By the time the brake is reapplied and hard the vehicle jumps ahead a few feet. I stress brake applied hard because it take full leg strength to make the brakes over ride the engine torque in low gear.

My wife pushes the brake pedal down hard before starting the Tesla which is a good practise. Unfortunately I don't follow her lead even though I should and know better. It only took one 'possessed' vehicle (80s Ford) which would launch itself for my wife to learn a defensive move during start up.

After decades in the tech business where service level contracts were negotiated we all knew that Hardware breaks, Software has bugs and People make mistakes. Some level of outages were to be expected and only recovery time was negotiable for remedies. I expect our Tesla to be similar in having failures. Unfortunately we do not have a Service Level Agreement with the company.

 

[whitex]

yes, and it appears from drawings that the brake pedal removes power from the motors directly even outside of software.

Which drawings are you referring to?

 

[whitex]

My wife pushes the brake pedal down hard before starting the Tesla which is a good practise. Unfortunately I don't follow her lead even though I should and know better.

How do YOU start a Tesla without stepping on the brake? Also, why step hard? Unless you're hitting the accelerator, the car isn't going anywhere even with light application of the brake.

 

[FlyF4]

Which drawings are you referring to?

design drawing. Not part of a sale or repair of the vehicle.

 

[Don85D]

How do YOU start a Tesla without stepping on the brake? Also, why step hard? Unless you're hitting the accelerator, the car isn't going anywhere even with light application of the brake.

The practise was the result of an ICE vehicle that would race the engine during start up. The same practise makes sense for the Tesla when you put it into D or R. I agree that the risk is small but light brake pedal pressure is not sufficient to overcome a surprise acceleration, that's all that I'm offering to the discussion.

 

[whitex]

design drawing. Not part of a sale or repair of the vehicle.

Can you share a link to the actual drawing?

 

[FlyF4]

Can you share a link to the actual drawing?

No online link; as you might expect, you have to be an employee or consultant of suppliers or Tesla to see any kind of proprietary documents for anything to do with any subsystem. While such documents can be available for some auto manufacturers or suppliers like Delphi, it is not true for Tesla and I think it is smart that they keep better control of repair manuals and related documents.

 

[DarkMatter]

The practise was the result of an ICE vehicle that would race the engine during start up. The same practise makes sense for the Tesla when you put it into D or R. I agree that the risk is small but light brake pedal pressure is not sufficient to overcome a surprise acceleration, that's all that I'm offering to the discussion.

How did the ICE move at startup? It would have been in park, or in neutral, as part of regular startup checks.

 

[Don85D]

How did the ICE move at startup? It would have been in park, or in neutral, as part of regular startup checks.

The problem was a sticky cable to the carb and the engine would race without warning. My wife experienced it and eventually refused to drive that car. It was unpredictable hence the need for hard brake pedal application especially when in close to other obstacles like parking or first moving in the mornings. During cold start the accelerator was pushed to set the choke plate then starter engaged so the rpm was unknown on start up. Even gentle application of throttle during parking could result in the engine not returning to idle so harder brake pressure was always ready to be applied. That was a long time ago but my message is that even a small V8 engine can produce a lot of power that the brakes are designed to overcome but only if you are ready for it.

This might have been a good reason for two foot operation but that's not how we were trained. Except perhaps during stop light drag races when brakes and engine power were both applied before launch. That was dumb, I know.

 

[DarkMatter]

I would not have been able to live with that problem. The moment it started to get sticky I would have been at Ford getting a new throttle cable. Good on you for figuring out how to work around it without hurting anyone, at least.

 

[whitex]

The problem was a sticky cable to the carb and the engine would race without warning. My wife experienced it and eventually refused to drive that car. It was unpredictable hence the need for hard brake pedal application especially when in close to other obstacles like parking or first moving in the mornings. During cold start the accelerator was pushed to set the choke plate then starter engaged so the rpm was unknown on start up. Even gentle application of throttle during parking could result in the engine not returning to idle so harder brake pressure was always ready to be applied. That was a long time ago but my message is that even a small V8 engine can produce a lot of power that the brakes are designed to overcome but only if you are ready for it.

This might have been a good reason for two foot operation but that's not how we were trained. Except perhaps during stop light drag races when brakes and engine power were both applied before launch. That was dumb, I know.

Even if the engine always started at full throttle, how is this a startup problem? If you had automatic transmission it would be in Park or Neutral to start the car, and require brake application to shift to Drive or Reverse. If you had manual transmission, your clutch should be disengaged when starting the car, equivalent of neutral.

 

[Don85D]

Even if the engine always started at full throttle, how is this a startup problem? If you had automatic transmission it would be in Park or Neutral to start the car, and require brake application to shift to Drive or Reverse. If you had manual transmission, your clutch should be disengaged when starting the car, equivalent of neutral.

Perhaps I need to be more clear on the reason for my original comment. An engine that accelerates on its own needs a lot of brake force to hold it back and with the element of surprise the car can lurch forward causing damage. How and when it happens is not important and my only experience was with a 1980s Ford that had to be restrained at times with extra hard brake force.

Restraining a car that wants to accelerate is not that easy. If you have already experienced this then you know what I mean.

Whether drive by wire cars are more at risk of this is a different debate.

 

[whitex]

Perhaps I need to be more clear on the reason for my original comment. An engine that accelerates on its own needs a lot of brake force to hold it back and with the element of surprise the car can lurch forward causing damage. How and when it happens is not important and my only experience was with a 1980s Ford that had to be restrained at times with extra hard brake force.

Restraining a car that wants to accelerate is not that easy. If you have already experienced this then you know what I mean.

Whether drive by wire cars are more at risk of this is a different debate.

"An engine that accelerates on its own" outside of startup scenario where it is in Park or Neutral is a safety hazard which should be repaired before driving the car, IMHO. Driving a car that can suddenly floor its own accelerator for no reason is as dangerous as driving a car with intermittent brake failures or bald tires.

 

[Don85D]

"An engine that accelerates on its own" outside of startup scenario where it is in Park or Neutral is a safety hazard which should be repaired before driving the car, IMHO. Driving a car that can suddenly floor its own accelerator for no reason is as dangerous as driving a car with intermittent brake failures or bald tires.

Agreed and the car was repaired. End of discussion.

 

[Pentium2004]

Another unintended acceleration through a wall. Hope this never happens to me!

Tesla Model X crashes through two walls and ends up in a gym, driver claims it accelerated on its own