Was Runaway Prius Really A Runaway? Or Just A Prank?

Also, if the car has ABS, it will be activated by mashing the brake pedal. That will prevent any of the wheels from locking up, so it will purposely reduce pressure on the brakes. The Prius has an electric motor as well as an ICE, and it is more powerful (60kW=80HP) in newer models. An ICE would stall if the brakes were locked, and starting torque is more limited, but an electric motor has a lot more low end torque. I think there are some fairly obvious factors that have been overlooked and perhaps some redundant safety features may have been phased out to cut costs.

Here is an excerpt from the specs on the 2010 Prius: "Star Safety System: Regenerative Anti-Lock Brakes (ABS) with Brake Assist (BA), and Electronic Brakeforce Distribution (EBD) Vehicle Stability Control (VSC) and Traction control (TRAC)"

So some of these safety features may conspire to create an unsafe condition. I doubt that engine vacuum is used for the power assist, as the ICE is not always running, and much of the motive power is derived from the electric motor.

There is also a recall for an ABS software problem:

The following indicates that the power assist for brakes is electrical. It also describes in some technical detail how the ABS, VSC, and EBD adjust braking pressure. And there may also be an issue with the Regenerative Braking Control. It states that the MG2 is mechanically connected to the front wheels and used to provide regenerative braking under normal deceleration requests. But it is only a little change of motor control software that makes the motor operate as a generator. And all of these software systems, AIUI, are activated only by the resistive sensors on the throttle and brake pedal position sensors. I don't think there is a backup pressure switch or end travel switches to detect extreme conditions and activate any sort of mechanical override or electrical kill switch.

All of these fancy controls are wondeful when working properly, but unlike mechanical systems they do not tend to fail gradually and gracefully so that problems can be noticed by the driver. Things can get dangerous if something goes wrong...goes wrong...goes wong..go on...go on...go go go go go!!!

Paul

well maybe the E-Brake which should be a cable driven device via the operator should have a kill switch in it..! It solves 2 problems. Driving with the brake on and being able to kill it incase of runaway..

Actually, management probably figured they could save a few bucks and get some hot shot young engineers at half the salary and lower insurance costs than their old pros whom they turned out to pasture. Old age, treachery, and experience will always trump the young and impetuous. Or something like that.

The fledgeling engineers right out of school probably show off their flashy talents for visual effects more than content, and dazzle the upper management with empty promises of quick, cheap, and highly attractive new designs. It's more pleasing to their egos than warnings from "old coots" who promote caution and costly back-up systems and vigorous testing. I can hear the mumblings of "I told you so" from the rocking chairs of the porches of recently downsized senior engineers.

Paul

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Almost true !

Except that if the computer is not working a fly by wire vehicle will not go into neutral since you are giving a command to the computer to tell the transmission to shift into neutral.

Can't the user just shut off the ignition key? Or is that interlocked "as a safety feature" when the car is moving? Or when in Drive, which might be interlocked for some reason?

Back in the day (early '70s) when I was a young engineer at GM's Cadillac division and most cars still had carburetors, if you shut off the ignition at expressway speeds while in Drive, the engine would "windmill" and continue to pull in air... and fuel, of course, from the carburetor. But since the ignition was off there was no spark, so the raw mix went straight to the catalytic converter where it burned so hot that the converter melted in a few seconds.

No interlock back then... ahh, the good old days!

Bob Masta DAQARTA v5.10 Data AcQuisition And Real-Time Analysis

That was fun then, you do that for a short time and turn the ignition back on! POW! :)

Common mistake by those who work for your namesake :-)

Yes, it's interlocked. ...to the steering wheel - bad plan.

Hell no. Engineers design saturating logic so overflows *cannot* happen. Programmers, on the other hand...

My Jeep has the key interlocked to the shifter. You can't remove it, except in Park.

The steering lock only engages when the key is *physically* removed.

Hence you can't put the steering lock on with the vehicle moving.

You certainly can (switch the car off and lock the steering column) with every car I've owned in the past 20 years. As I said, bad plan!

Ha! The resonator on my mom's caddy exploded on startup once. Quite a surprise to say the least.

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Are named Maynard...

Excuse me pecker head?

yes, that is what I called you. The name is fitting. Exactly!.

Go back in that corner and beat your head against the wall, you haven't yet got it straighten out..

Look, I don't want to get in a battle of wits with you, I don't like fighting with an unarmed man!

Then quit abusing yourself.

Bad plan indeed.

An interesting thought has emerged. The Jeep has provision for flat ("recreational") towing (say on an A-frame), with the transfer case in neutral. The manual says the transmission should be in Park when doing this. I don't know whether the key needs to be in, or whether the (electric) steering lock comes off automatically. I don't have an RV, so I never needed to try it. I shall have to find out.

I hate being stuck behind some monster RV with an SUV in tow!

Don't know about Jeep but a friend has a Saturn that he tows behind his land yacht, "four down". IIRC he has to leave the key in the ignition to unlock the column. There may be a position where he can remove it, don't remember.

No worse than an 18-wheeler.

I'm shocked! SHOCKED!

You could knock me over with a feather!

Bret Cahill

CHP is now claiming it was an honest mistake.

I don't really give a rat's behind if I get killed by a motorist making an "honest mistake" or a vicious murderer trying to kill me.

I just don't want it to happen.

The price of these "honest mistakes" has been and should be stiff fines.

Bret Cahill