Some quick help

Eat-um-up · Eat-um-up's Garage

I am doing a persuasive reaserch paper for my english class... Now this is gonna sem dumb but i need another source. I know what can happen with newer cars or plains when computer systems fail. I just need someone to say what inconvieinces or faults may happen when the onboard computer systems might fail for an interview type of source. And if your a mechanic or work in parts... (witch im sure you all do) plaese let me know so i can list the credibility. Thanks Everyone

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Sweet Blue 72' 914
Check it out at
http://www.geocities.com/eat_um_up/914.html

914GOD · 10-19-2001, 09:28 AM

Onboard computer system failure can lead to anything from an inconvenience all they way to total catastrophe. Computers in todays vehicles (to name only one general catagory) control every aspect of their operation. Consider the fly-by-wire sytem in an aircraft. Should this sytem fail the plane will crash. Newer cars are equiped with OBD II and III computers, eventually computers like this will contact government agencys when your car is not running right. This computer could fail, leaving you stranded or simply tell CARB (california air resources board) that your car is putting out bad emissions, which of course means CARB will come and get you...talk about an inconvenience!

At the same time, computers allow freedom in design that was not possible several years ago. They have progressed to the point that they are cheap and very reliable. Consider the computers in all of our beloved 914's, 30 years old and a very rare part to fail! My car is on its fourth engine, but still it's first computer.

Sean Saint
Mechanical Engineer

Dave at Pelican Parts · Dave at Pelican Parts's Garage

Uhhhmmmm, in a word: "No."

The whole "eventually OBD computers will call CARB to arrest you" bit is just ludicrous.

Current automobiles have fail-safe mechanisms built in. When some part of the computer fails, the "Check Engine" light comes on, and the computer defaults into a "limp-home" mode. This mode usually ignores all but the most basic (and hopefully bulletproof) of sensor inputs, and is only guaranteed to make the car run at all. Not to run well, just to run.

If the computer fails completely, or the really basic sensors (RPM, for instance) fail, the car simply does not run. This is an inconvenience in a car, but not fatal.

Aircraft, on the other hand, can cause fatalities if they fail. That is why FAA certification is almost overboard on the level of fail-safe and redundancy that they require. Particularly on airliner-type aircraft.

Many aircraft have manual backups to the computer-operated systems. In fact, it is required for most or all critical systems that are computer-operated. That means that, if the computer completely fails, there are still means to control the system.

It usually takes a chain of failures (usually more than three) to cause a single "incident". Failures can be equipment failures, improper maintenance and/or inspection procedures, pilot error, and so on. You can't get an aircraft certified currently where any single-point failure can result in a loss of control. There may not be three redundant backup systems, but there are always several different ways that failures can be prevented. All of those have to fail before Something Bad happens.

I've been around aircraft (mostly home-builts) since I was born. My grandfather and father have built or are in the middle of building a number of planes. And my "day job" is working for a commercial-jet flight simulator at NASA.

--DD

JP Noonan · 10-19-2001, 02:25 PM

Ummmmmmm, in a word, "yes"
Big brother is watching.

If you have a BMW with On-Star and you are in a wreck it will call rescue/towing/police depending on the incident. The computer can tell if the air bags were deployed and the attitude of the car. It happened at a club event (soory, can't remember where, I want to say Mid-Ohio but I couls be wrong), someone got the shinny side down and next thing you know the parametics are driving into the paddock....

Needless to say his insurance company knew

a. how fast and what G forces were being pulled.

b. and that he was involved in a "track event" or "speed contest" which voids any claims.

Eat-um-up · Eat-um-up's Garage

Thank You Everyone. This is just what I need.
James

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Sweet Blue 72' 914
Check it out at
http://www.geocities.com/eat_um_up/914.html

914GOD · 10-19-2001, 04:08 PM

As a matter of fact the original idea for OBD III was in fact to have the car contact the government (I am not sure which agency) when certain things happened with the car. This has now been pushed out to OBD IV I believe. By the way, I didn't say arrest, I said "come and get," which was meant to mean force you to fix your car.

Regardless, the point of my post was not a ditribe on the safety of aircraft, I agree with your comments on redundancy. It was to help eat-em-up pass his english class!

When I said Mechanical engineer I should have added Society of Automotive Engineers.

Sean

[This message has been edited by 914GOD (edited 10-19-2001).]

john walker's workshop · 10-19-2001, 05:31 PM

eat em, have someone check your spelling before you turn in that paper. friendly tip

Joe Bob · Joe Bob's Garage

URBAN FREAKIN LEGEND....

First off, it is against FEDERAL LAW to do unsupervised tracking of a vehicle THAT YOU OWN. You need a warrant signed by a judge to that....take a look at the constitution....

"You" can ACTIVATE a tracking system to find you, you can ACTIVATE a system to fix or find faults in your engine, IF YOU OWN the car....

ALL bets are off if you lease or rent....even though some have successfully challenged surcharges for speeding, abuse and going 95 mph after a check engine light comes on, and such....

YMMV

Take a look at the History books that you were supposed to read in 8th grade....