Runaway Lexus story makes me wonder about electric cars..

[Fumesucker]

Electric cars are by their very nature "drive by wire" and the great majority of them don't have a transmission you can put into neutral.

If a Lexus can go into runaway acceleration and crash when being driven by a trained highway patrol officer, what's going to happen when an electric car goes into runaway acceleration?

People think of electric cars as being slow but the Tesla roadster is anything but that, if it sticks at full power you're either going to get on the brakes hard and fast (something the Lexus driver didn't, in my educated opinion) or you're going to crash big time.

The first time this happens with an electric car it's going to get *huge* negative press, you can count on that.

[hobbit709]

1. Maybe they should install a kill switch.

[Fumesucker]

2. Problem is that people panic..

And even a trained person didn't do what is to me the obvious thing in the runaway Lexus incident, put the tranny in neutral.

And an easily accessible kill switch can be an accident waiting to happen too if a passenger pushes it either deliberately or accidentally or if the driver does so too.

It's just something I've started wondering about this morning after posting on the runway Lexus thread.

[madokie]

9. Maybe the gear selector is locked in gear when the engine is running

I recently built an offroad vehicle for my brother to use in his sawmill and portable building business using the front transaxle and the rear differential from a '77 subaru all wheel drive using a 36 volt electric motor and one day early on I was checking it out, you know getting antsis to see what it'd do and the throttle switch I was using malfunctioned and it was impossible to pull the shifter out of gear as long as the thing was going on a level or up hill some. I finally crested a little bump in the trail and when I was coming down the other side the shifter was easy to move to neutral but if I'd been on one of the many trail/roads on his 500 acres of north east oklahoma hills I could have been hurt or my project ruined.

heres a photo of it

[Fumesucker]

11. Wow.. Kudos to you, that thing is cool..

Yep, when there's a load on a manual transmission they can be hard to shift out of gear.. Has to do with being hard to slide the gears back and forth with pressure on them, tranny isn't designed for that..

Did you not use the clutch when building the beast?

And this is another story of exactly what I'm talking about, I'm glad I did the OP since I wasn't expecting to get these stories.

[madokie]

13. No I didn't but I could and now that you mention it I may put an emergency clutch

which would be simply making the parts to move the belt idler I'm using to keep the belts tight now. I mounted the electric motor where the starter normally is on the subaru tranny, on top of the bell housing with the electric motors shaft going through the starter mounting hole in the bellhousing, and I'm using a two belt drive with a four to one ratio between the motor and the input shaft on the tranny for a total of 64 to one ratio when in first gear. Put it in four wheel drive and first gear it'll go about anywhere, up or down. Its a pretty neat setup as the belts and pulleys are enclose within the two halves of the bellhousing. I put a bearing where the pilot shaft normally is to take the side load from the belts. If you'll notice I built it with very little overhang in front or back and a high center so he can cross the gullies that will be at the bottoms of his many big hollers.

In first gear one revolution of the motor moves the car 1 inch forward, in fourth gear it's 4 inches to one revolution. If I would have had anymore room in the bellhousing I'd like to have put a lower ratio than the four to one I have now. A six to one would be ideal but without putting in a jack shaft which I don't want to do, I can't get there from here.

[Vickers]

21. Damn, I wish you were my neighbor.

I am forever building stuff from the crap I have lying around.

:thumbsup:

Very cool "crawler" ya got there.

[dionysus]

29. damn.. that's cool.

[eppur_se_muova]

17. But that would cost $1 extra -- so it won't happen. nt

[imdjh]

3. As a rule, when sailboats collide, no one dies.

[Fumesucker]

5. I guess you didn't see my electric bicycle thread the other day..

A 45 lb total weight electric bicycle that can go 60 mph and accelerate like an F16, the single biggest difficulty riding it is keeping the front wheel on the ground.

Electric does *NOT* necessarily mean slow, you are revealing your lack of knowledge of the subject with your comment.

[pokercat999]

14. Could you make it front wheel drive?......nt

[Fumesucker]

16. Sure, but then it would just smoke the front tire..

The bike was all about acceleration rather than sheer speed, in a single wheel drive vehicle acceleration is all about getting weight transfer onto the driving wheel. Front wheel drive vehicles are inherently limited by weight transfer as to acceleration.

Here's the thead, in case you're interested..

http://www.democraticunderground.com/discuss/duboard.php?az=view_all&address=389x6699545

[lumberjack_jeff]

25. A sailboat is a poor analogy for anything fast enough to operate on US roads. n/t

[Cirque du So-What]

4. I'm not sure whether this has any bearing on the OP

but in a previous life, I worked in heavy industry, and this story involves an electric vehicle - an electric fork lift. The operator told his supervisor, who in turn called for the electrician, that the truck had been 'sticking,' requiring him to hit the 'kill switch' in order to bring the vehicle to a halt.

The electrician who showed up was a brash, brainless fool who I referred to as 'Samurai Electrician,' named for John Belushi's samurai character on SNL (before they sucked). Everyone told him the problem, but he dismissively climbed aboard the fork lift and pulled the switch down into reverse. The truck took off at full speed - the electrical contacts now welded together - backward, toward the rail dock and a 4-foot drop.

I'll never forget his expression of helplessness & horror as that truck was zipping backward toward the rail dock, and of course he didn't have the presence of mind to hit the 'kill switch,' so the truck went over the edge of the rail dock. Surprisingly, he only had some sprains & strains from riding the fork truck all the way - proof that God does look out for dumbasses.

I've thought of that incident ever since hybrid vehicles started taking to the highways. There must be a main contactor on these vehicles through which a LOT of current flows, and unless they make contact in an absolute vacuum, there will be little arcs every time they make contact. Over time, the surface gets rough, making the arcs that much more intense, which exacerbates the problem. Eventually, it's possible that they could weld together, just like that fork lift. I hope drivers of these vehicles know how to cut the power in case of an emergency.

[Fumesucker]

6. Great story..

:rofl: at the Samurai electrician..

And yes, this is exactly what I'm talking about, thanks for posting.

[Ian David]

7. There will probably be a computerized sensor that detects these problems and shuts the system down.

[Fumesucker]

8. Your computer has never crashed?

You must be posting from a Mac.. ;)

[LiberalFighter]

10. I"m not aware of there being a kill switch on a fork lift truck.

I was not aware there was one. The only other way to stop the vehicle would be to disconnect the cable.

After research the only type of fork lift that I could find that had a likelihood of having a kill switch would be those that was intended to lift people instead of stock.

[Fumesucker]

12. Most industrial equipment has a kill switch..

Big red button you push usually..

Even tanning beds are required to have a kill switch in some localities.

[LiberalFighter]

22. I drove fork lift trucks 3 years ago and there were no red buttons.

But it did require body weight on the seat for the truck to work.

[-..__...]

24. Self delete.

[Odin2005]

15. "Samurai Electrician" ROFL!

Great story! :rofl:

[flvegan]

18. The Tesla has a neutral gear.

I'm hard pressed to think of an electric car that's in production that doesn't.

[Fumesucker]

19. Anything that uses a hub motor doesn't have a neutral gear..

Electric cars aren't very common yet so there really isn't much to look at..

But the very first time you get a runaway electric car like that Lexus it's going to be a huge story, the M$M won't be able to resist it (pun intended).

[Statistical]

28. Are there any EV that have hub motors?

It will take some time to design good regulations on EV but even vehicles with hub motor could be "safed" by having a kill switch (something like a relay not computer controlled). Something like an easily reachable red button on dash with "Push and hold to halt engine." Eventually a universal symbol for kill switch will become common place just like hazard signal icon is now.

[NutmegYankee]

20. Oh! Electric cars are not slow! I totally agree with that.

I have been part of a team that built a few, and the torque was so rapid and intense that we ripped a few Chevy Suburban drive axles apart.

The safety we had was two large solenoids that connected the battery pack to the motor, and you could hit a switch and open either one and it would interrupt power to the motor.

[high density]

23. The Lexus issue was the driver not knowing to hold in the start/stop button to stop the engine

Or how about shifting into neutral? (Drive by wire has nothing to do with that.) Or slamming on the brakes? (Supposedly the brakes weren't working.) There were multiple ways to stop this car and for whatever reason he failed to do so. It is not a reason to condemn an entire technology.

[Fumesucker]

26. I wasn't condeming the technology..

Just pointing out an eventually inevitable mishap and the equally inevitable M$M reaction to it.

After all, infernal combustion autos have been around over a hundred years and we still get runaway acceleration mishaps on a fairly regular basis.

In fact I'm very pro-electric, as evidenced by my recent OP about electric assisted bicycles.

http://www.democraticunderground.com/discuss/duboard.php?az=view_all&address=389x6699545

[lumberjack_jeff]

27. EV technology is immature.

Safety concerns abound, and not all of the pitfalls have been identified.

On the EVs I've seen, brakes don't stand a chance against a motor which has all of its torque available at zero rpm.

There is also a fire risk. It's taken 100 years to get gas autos as safe as they are.