[WARNING] Running out of gas (Gen III)

[CAR4TWO]

Your chance of having a flat tire is once in every 100,000 miles. I can not believe this discussion. My rule is that I will go down to an 1/8th of a tank. After that, I'm looking for fuel. In the airplane, I will not let it go below 1 hour left in the tanks. I have to find an airport in the next 120 miles. Seriously, I want gas before I start to use that last hour in the airplane. Letting your car run out of fuel is flat out the dumbest thing anyone can do.

What do you call those bars? Pips? The Prius tells you how many miles you have left in the tank. At 50 miles, I would be looking for a gas station. Knowing me, I would be looking with 75 miles showing. Every good driver should know when it is time to top off the tank. It is flat out irresponsible to run out of gas.

There is a lot of common sense on this BB. I especially liked, "Keep the gas tank full, problem solved." All cars can run out of gas and they all come to a complete stop when they do. It sounds like I am speaking to a group of new drivers. I'm actually laughing as I write this. You are taking all this to seriously. By the way, if the gas gage starts to flash, fill it up. How hard is that?

Thanks for the laughs! I was wondering why so many were posting to this thread. Well, now I know.

[steve44]

Originally Posted by bwilson4web

There are bloody, deadly reasons why a Prius that has run out of gas should get to the shoulder or a safe place. In this case:

Bob Wilson

So, who killed who? Was it the car's fault for not providing more than 2 warnings or was it the drivers' fault for ignoring the warnings and not filling up the tank prior to getting on the highway?

Thanks for justifying your lack of judgement. Stop blaming technology and sack up. You are a bad driver for risking other people's lives. As you stated, this is a serious situation when a car runs out of gas (SEE ABOVE PICTURE). YOU are contributing to the next death.

[Therand]

Originally Posted by bwilson4web

Running out of gas should not be a capital offense in Prius with enough traction battery energy to get out of the way.

Bob Wilson

I work as an engineer and I am always designing for rare events. The problem with your detractors is that with any rarely occurring event, time is the great equalizer. If given enough time, the likelihood of something rare occurring approaches a certainty.

The really curious part of all of this is the actual lockout itself. Why design such a lockout in the first place? A few people are speculating that it is for increased traction battery life. I cannot see how this speculation is true since Toyota engineers provide a way for people to directly use the traction battery (ie EV mode). If battery life was such a serious concern why allow a customer to put such an extra strain on a battery? Batteries normally have a limited charge/discharge cycle life. EV mode seems like a much more efficient way to destroy a battery than allowing a driver to use the remaining charge during "out of gas" situations. Since the EV mode button made it to the production model, I can infer that Toyota engineers were confident that regular usage of the EV button wouldn't impose a financial burden on Toyota's battery warranty program.

I think it is much more likely that this was a simple oversight by the person programming the main system and not an on-purpose change in the product.


Many of your detractors are saying "Well don't run out of gas". While this was the particular way you tested the emergency functions of your Prius, it is not the only possible way to get into an emergency situation. There are probably hundreds of ways a person can find themselves in a vehicle without ICE power. A clogged fuel filter or broken fuel pump come immediately to mind.


I am not a lawyer but I sense a good case against them for this particular design limitation/oversight. Their disregard for human safety may hold up in court given the fact that they included an EV button and they had previously allowed for emergency maneuvers in a prior design.

[bwilson4web]

Originally Posted by alam99

. . .I think Toyota could put in a very annoying sound and flashing light system that continues to blare while driven in EV mode until the car gets some gas, but maybe the current scenario where the car simply stops running when out of gas is the simplest, least confusing, least detrimental way (public relations, etc) way to handle it.

I agree and have a few suggestions:

• works with "emergency flashers" - if the ICE will not run for any reason, the car can use the traction battery down to the usual limit, 40%.
• may require pressing EV - a positive act by the driver that they are using the remaining motive power.
• speed limited - 9 mph, enough to get to the shoulder and/or creep along. Requires "emergency flashers."
• no accessories - no AC or radio to extend range.
• all fuel bars flash - either flash them in unison or repeat starting from all bars going to empty, cycling over and over again, something better than "power steering failure."
• back-up beep at 42% SOC - at the very end, start the backup beep ... park NOW!

Stuff happens and regardless of why the engine is not working (there are reasons having nothing to do with no gas,) if the vehicle still has enough traction battery, let the EV mode work.

Bob Wilson

[fred garvin]

Originally Posted by Therand

I work as an engineer and I am always designing for rare events. The problem with your detractors is that with any rarely occurring event, time is the great equalizer. If given enough time, the likelihood of something rare occurring approaches a certainty.

The really curious part of all of this is the actual lockout itself. Why design such a lockout in the first place? A few people are speculating that it is for increased traction battery life. I cannot see how this speculation is true since Toyota engineers provide a way for people to directly use the traction battery (ie EV mode). If battery life was such a serious concern why allow a customer to put such an extra strain on a battery? Batteries normally have a limited charge/discharge cycle life. EV mode seems like a much more efficient way to destroy a battery than allowing a driver to use the remaining charge during "out of gas" situations. Since the EV mode button made it to the production model, I can infer that Toyota engineers were confident that regular usage of the EV button wouldn't impose a financial burden on Toyota's battery warranty program.

I think it is much more likely that this was a simple oversight by the person programming the main system and not an on-purpose change in the product.


Many of your detractors are saying "Well don't run out of gas". While this was the particular way you tested the emergency functions of your Prius, it is not the only possible way to get into an emergency situation. There are probably hundreds of ways a person can find themselves in a vehicle without ICE power. A clogged fuel filter or broken fuel pump come immediately to mind.


I am not a lawyer but I sense a good case against them for this particular design limitation/oversight. Their disregard for human safety may hold up in court given the fact that they included an EV button and they had previously allowed for emergency maneuvers in a prior design.

was the pillow comfy at the Holiday Inn Express last night?

[Midpack]

Originally Posted by Therand

I work as an engineer and I am always designing for rare events. The problem with your detractors is that with any rarely occurring event, time is the great equalizer. If given enough time, the likelihood of something rare occurring approaches a certainty.

I am also an Engineer with 32 years experience. I've never had the luxury of designing for events that a) occur 0.1% of the time or less after ignoring all sorts of other earlier warnings (miles to empty, fuel guage, warning light) and b) the severity of the failure is minimal (you pull over stranded, not the end of the world). I can think of a lot of potential features with higher probability of providing a benefit. A good Engineer would factor in probability and severity, I'd be willing to bet the Engineers at Toyota do. For landing planes, defects need to be zero because of the severity. For a car running out of gas with all the early warning already provided, the probability is low and the severity is almost nil. The wreck pic is clearly grasping at straws.

And as another poster said, Toyota might not want drivers to think 'running out of gas is no big deal because I can drive on battery to the next gas station.'

[bwilson4web]

Originally Posted by steve44

. . . Tell me something, BWILSON, what do others in your life say about your judgements overall?

Well since you asked,

Originally Posted by others in your life

Why thank you Bob Wilson for the courage to do the experiments that terrify so many and insights about Prius safety. Your generosity in sharing the facts and data yet humility and willingness to admit mistakes and apologize are well known in the Prius community that you have served for three and a half years. You remain an inspiration with your subtle sense of humor that makes laughing with you more fun than the recent 'kick me' posting by "steve44." (My thanks to Tom Cruise in "Saving Private Ryan" describing why the mission was so important.)

Personalities? Good grief! It is a simple engineering problem that probably can be fixed with a software change. Better still, it may already be an undocumented feature awaiting the right experimental test.

Bob Wilson

ps. To own a Prius already makes us "kooks" in many minds ... or have you not been following 10 years of hybrid skeptics?

[HTMLSpinnr]

I'd have to say I'm in the same mindset as CAR4TWO, the pilot training and former winter driving in the mountains experience says don't let the tank get below 2 pips. I usually fill at 2-3 pips. I've NEVER allowed myself to run out of gas.

My wife (whom I love dearly) has only done it once (in a Gen I and was thankful she could pull off and park in a lot). She knows not to let it happen a second time.

With my personal discipline, I don't think this behavior change is an issue. With the Mrs., it'll be a nice to know if she's ever driving this car.

[Therand]

Originally Posted by Midpack

I am also an Engineer with 32 years experience. I've never had the luxury of designing for events that a) occur 0.1% of the time or less after ignoring all sorts of other earlier warnings (miles to empty, fuel guage, warning light) and b) the severity of the failure is minimal (you pull over stranded, not the end of the world). I can think of a lot of potential features with higher probability of providing a benefit. The wreck pic is clearly grasping at straws.

I'm not sure I agree with a 0.1% occurrence rate. Most vehicles have at least one failure or breakdown in their lifespan.

The risk to a driver is dependant on the situation. You cannot assume that a driver will be able to pull over during a failure. I can envision the rate of ICE failures is more likely to happen during start/stop cycles than while at speed. An ICE failure while in the middle of stop-and-go traffic could be a serious issue - even life threatening. How about an ICE failure while crossing railroad tracks? Or while on top of railroad tracks while waiting at a red light? (Yes, I know you are not supposed to do that. It does not change the fact that it happens.)

Automobile manufacturers have always had to contend with out of the ordinary situations. I still think this was a programmer’s oversight and not a deliberate action by Toyota; however, that does not change the fact that I would rather have this missing feature. The question I really want answered is, "How do we get it back?"

[viking31]

Originally Posted by alam99

I think Toyota could put in a very annoying sound and flashing light system that continues to blare while driven in EV mode until the car gets some gas, but maybe the current scenario where the car simply stops running when out of gas is the simplest, least confusing, least detrimental way (public relations, etc) way to handle it.

Or Toyota could put in a nifty display on the dash next to the speedometer; let's call it a 'gas gauge' that flashes on the last pip for over 100 miles of driving (about two to three hours of continuous driving in most cases)...

Oh, my mistake, they already do... must be a new gizmo for the 2010 cars... imagine that, a device that warns you 100 miles and more in advance to pull over and get fuel... Pure genius...

Rick
#4 2006