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cvandewater
User Rank
Gold
Re: Inaccurate reporting
cvandewater   3/31/2012 7:29:41 AM
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Hi Myron and Ervin,

I expect that every commercial vehicle will be resilient against and tested (at *design* level) for operation normally when power is lost while moving.

That has also been my experience with electric and hybrid vehicles - whether my Prius running in EV mode or my electric S10 truck. No problem when turning the key OFF or popping the gear selector in Neutral while moving. In fact, the gear selector can be moved to Reverse in these AC (Alternating Current) drivetrains while moving and the accelerator pedal then becomes a brake pedal for decelerating the car (pushing electric power from the motor back into the battery) until you are at standstill, then it becomes accelerator pedal for reverse. The function does not really change - the pedal is giving you a negative acceleration the whole time.

The controls you were witnessing to pop while running were either incorrectly designed or experiencing an unforseen operating condition or latent fault, because a well designed controller should not break down under these conditions, even when it is a DC controller as you appeared to be testing.

melllowfelllow
User Rank
Gold
Headlines and more...
melllowfelllow   3/16/2012 11:34:30 PM
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Chuck,

I'll chime in on the headline issue. The intense pollution of the US English language can make selecting a clear slang word difficult. I surveyed 6 folks [engineering types] WRT the word 'bricked' - 4 of 6 interpreted 'bricked' as 'dead and useless' [it was not expressed this exact way by everyone, but this was the normalized interpretation]. It would seem that something like 'dead in the water' or 'totally immobilized' would have been more accurate. Of course 'bricked' could be one of those words with 'east coast' and 'west coast' connotations that totally escape this Texan.

General -

The failure - without speculating on the actual 'breakage', the real failure was a software failure. Since something was amiss, the software should have been able to identify and clearly communicate the failure. Instead "The manual advised the engineering team to contact the dealer". Are they for real? An advanced technology vehicle that does not provide a useful error message does not 'send a positive message'. Maybe the autopsy will shed some light [or smoke] on the subject.

No comment on the political-religious comments.

Whether the failure occurred at CR's doorstep or some unknown consumer's doorstep, the real questions are "what really happened?" and "why?". Time will tell...

MYRONB
User Rank
Gold
Re: Inaccurate reporting
MYRONB   3/16/2012 2:34:22 PM
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To Ervin0072002,

Thanks for your comment.  I believe these are the same phenomena.  In forensic engineering, switching off electrical power while the motor is turning, in my opinion, falls into the category of "foreseeable misuse," and makes the manufacturer liable for repair or replacement.   The system designer must consider these factors and provide protection in the basic design to avoid material damage or personal injury arising from this system failure.  Remember that electric forklifts with solid-state controls have been with us since the early 1960s, so the technology for motor control is not new.

Regards,  Myron Boyajian

ervin0072002
User Rank
Gold
Re: Inaccurate reporting
ervin0072002   3/16/2012 1:03:31 PM
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Hey MYRONB,

I have seen this happen before in a different setup with electric motors. I was using a driver to control the speed of a regular AC motor. Had it ramped to 10k RPM and then I applied a dump resistor across the motor to slow it down. Sadly the person that had installed the drive had calculated the break resistor wrong so the current spike was too great for the IGBT to handle. This was a 100A IGBT and it melted. I assumed that automotive would have some spec for obvious things like this for cert... And then maybe not it is a new field even though hybrids have been around for year's requirements and specs follow at a slower pace.

MYRONB
User Rank
Gold
Re: Inaccurate reporting
MYRONB   3/16/2012 12:38:16 PM
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Back in the bad old days when cars were powered by I.C. engines, a car being "bricked" meant something altogether different.  Automotive delinquents' idea of fun would be to start the engine, and with the transmission in neutral simply place a brick on, or otherwise hold the throttle wide open until the engine blew.

As far as electric cars go, I was retained to explore different energy recovery systems on a small electric car used for deliveries in gated communities.  A coast-down test required running at a set speed and shutting off power to coast to a stop.  At the moment of power cutoff, I heard a popping noise, and after coasting to a stop, the car no longer moved under its own power, being effectively turned into a brick.  A new controller had to be fitted to restore operation.  The control manufacturer didn't offer any failure analysis, but I believe at power cutoff, the rapidly collapsing magnetic field in the motor induced a high voltage spike that damaged the solid-state controller.

 


 

ervin0072002
User Rank
Gold
Re: Inaccurate reporting
ervin0072002   3/15/2012 7:30:58 AM
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I will have to agree with cvandewater. I'm not usually optimistic about things. I generally see worst case scenario. But in this case it's not so. Personal experience has shown me that Electrical systems can be simple robust and long lasting. Electrical systems are far more reliable than any mechanical or chemical system out there. Also I don't think I know of a single car manufacturer that has not had a recall or a revision on every vehicle they have ever produced. The number of components a car has makes it impossible to design it without a flaw. Look at some of the leading luxury manufacturers you will see a good number of recalls in their midst too. Because you buy luxury does not automatically imply good quality. Just means you are buying the design and the name. Pretty things don't need to be sturdy. Also keep in mind that a gamma distribution can show a low probability of infant mortality however it does not completely remove the possibility.

John
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Gold
Funny article
John   3/14/2012 10:11:41 AM
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I thought this article was rather funny.  Funny yet embarrasing for the manufacturer.  I don't think I would say it is black eye for the company.  Consumer reports might be a good base line feel for products, but they don't test all and they will probably tell you a 4 cylinder car is zippy quick.  Grain of salt.

cvandewater
User Rank
Gold
Inaccurate reporting
cvandewater   3/14/2012 4:01:02 AM
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Hi Charles,

I see your defense against sensationalist reporting in an earlier comment, but I would say that there is at least one count of incorrect reporting and one count of suggestive allegation without being clear about the facts.

Reading the CR article, they are careful to say "We buy about 80 cars a year and this is the first time in memory that we have had a car that is undriveable before it has finished our check-in process."

Since they explicitly specify that they only never had a car fail *before* their tests, there may have been many cars failing during their tests, so you are wrong in reporting an unqualified statement that they have never had a car fail, or did you contact CR to verify that this was the first car ever to fail on their test track?

Secondly, about the disputed "Bricked" status. Very recently there was a large deal made out of some private person's issue with a Tesla that was stored too long and with an empty battery that was not designed to survive this neglect so Tesla (right or wrong) decided not to honor the demand for a replacement due to this neglect, after which the private person started an internet campaign trying to give Tesla a black eye for what he felt was an injustice, trying (and failing) to implicate that this was a common problem. Today you are again using the same term "Bricked" that did not occur in the CR reporting, so by coloring the Fisker with the same term, you are implicating that the same problem has occurred and the emotional message that is sent by the chosen term "bricked" is that the device has been rendered useless and lost all its value, has become a door stop.

However, in the CR report there is none of this message to be seen. A car has developed a fault and needs to be returned to the manufacturer. That happens every day and can be as simple as a blown fuse or an incorrectly programmed controller. I know, because I used to own an electric truck with very strong regen braking and I could program the controller to allow regen to trip an overvoltage level that would instantly disable the controller to protect the other circuits. Another AC controller that I had even displayed the exact behavior that this Fisker developed, including that I could reboot it back into idle and put it into drive mode, only to see it fail immediately upon requesting any movement. The reason was very simple, one of the 3 motor wires was not tightened so within the first minute the wire lost contact while carrying current, probably caused a spark and the spike killed one of the motor control transistors. The safety cut power due to the short circuit and the result was no-go, even though I could reboot it back into idle. In my case it was a $250 e-bike that developed this error and the replacement transistor cost $1.

To make a long story short: unless you have received more information than CR is reporting, there is no reason for you to add or change decriptions and color events to suggest a relation with earlier events that caused expensive EVs to lose almost half their value, while it may be a trivial programming error in this case. CR reported the event quite neutral, so I am wondering what the reason is that you chose to report it differently. I must say that is smells of sensationalist reporting, but at least it appears to be wrong. Let us know if you have received more information than CR and that caused you to report differently.

oldtimer8080
User Rank
Gold
Re: $100 Fisker Karma EV
oldtimer8080   3/14/2012 1:59:48 AM
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" Bricked " is a vaild term that applies to the FACTS.

You either are an Engineering Manager who has been behind a desk for too long or you are one of the " engineers " at Fisker...

Or are you stuck with the " investment "  in Feelgood Hybrids & EVs?

Iv'e worked with the BOLDER TMF cells used to power the TRUE series hybrid by Chrysler. You see TRUE hybrids at work when you are sitting at a RR Xing when a train goes by..

No exotic chemicals to reclaim; The TMF cells are L-A based and just as recyclable.

 

Too bad the company was allowed to be outsourced...

.

 

 

 

 

 

PJ
User Rank
Iron
Image Issues
PJ   3/13/2012 8:35:52 PM
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Cool car. Electronics can be rectified but why let "Two and a Half Tools" damage your reputation.

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