[ausev] EV Electrical vulnerabilities, was Filmmaker looking...

[jefoy at mindspring.com]

With due deference to Dan's expertice and experience I find the idea that mass numbers of ICE vehicles are damaged by lightning induced EMI to border on the absurd..

Taken in context, the modern ICE is a wonderfully designed engineering marvel when it comes to electrical integrity. 

1. Logic devices historically have been designed around 5 VDC logic levels. Modern MPUs run closer to 3 VDC to reduce heat. The auto has developed around 12 VDC systems and this inherent mismatch neccesitates the use of electrical isolation where the automobile system interfaces with the MPU. 

2. Given the auto still has hundreds of feet of electrical wiring that can be an "antennae" for picking up EMI, the fact that the entire system is encased in a steel (conductive) shell and isolated from ground (tires) make it well hardened for any but the most severe ESD or EMI events.

3. Having been in the business of repairing electronic systems for the last 25+ years, I can tell you that the vast majority of problems occur in the interconnect area, not discreet electronic devices. 

That said, in my current occupation I work for a major OEM producing equipment for the semiconductor industry. From that perspective, there are a host of "soft fail" problems that can be induced in the processors and related discreet devices used in any electronic system during the manufacturing process. These mechanisms create subtle but measurable changes in the device characteristics and can lead to the exact types of response being blaimed on lightning. It is a major headache to auto manufacturers and is passed on readily to the semiconductor manufacturers as an "avoid at all cost" problem since it leads to what the auto industry calls "walk home" events. 

Unfortunately, the EV industry suffers more than the mainstream auto industry simply due to the production scale. Motor controllers for the EV market are a niche industry and really don't get the attention that the OEM auto industry can afford in terms of continuos improvement projects. Switch mode motor controllers create an inherently noisy environment worse than anything nature can produce. Heat, EMI, unstable regulation circuits, marginal overhead on operating limits, etc.. all contribute to the relatively high failure rate for current EV motor controllers. 

The EV, in the hobbiest form, can be a simple system to troubleshoot to the "black box" level. Beyond that, failure within the motor controller is usually traceable to a marginal design and is not likley to change untill the EV market expands enough to create the parts volume required for real, failure analysis driven, continous improvement projects. 

BTW, the GE built SCR controller from my Jet 007 (1981) still works.. Hopefully it will find a home in a newer vehicle in a year or two..

Jack Foy
Product Support Engineer
Axcelis Technologies


-----Original Message-----
>From: jtp <jtp at onr.com>
>Sent: Oct 24, 2006 2:38 PM
>To: eeyore at phototropia.org, AustinEV News Announcements and General Discussion <ausev at austinev.org>
>Subject: Re: [ausev] EV Electrical vulnerabilities, was Filmmaker looking...
>
>Chris,
> I do think that an EV controller can be designed to have a replacement chip
>pre-programmed and standing by in a sheilded case, or can be properly
>remanufactured in far quicker "turnaround time" than what seems available
>currently as you have advised.
>  It is partly a matter of market size.  The other things that must be taken
>into account is that all auto parts suppliers would POUNCE on any
>opportunity to do business with outstanding professionals like you whom know
>WHAT they need in the first place without undue risk of having a part
>returned (unless truly defectively remanufactured).
> This is  because of  all the "swap testing and diagnostic experiments" or
>emperically/historically-based ineffectual and usually INCOMPLETE "work"
>which plagues the ICE-motoring public, which occur  from well-meaning
>do-it-yourselfers, and insufficiently-trained others
>whom  postpone (usually from economics), their professional advancement in
>equipment and training, (or are led to buy the wrong equipment and/or
>training).
>There are 538,000 VERY DIFFERENT electronic integrated systems in ICE
>vehicles today.  Just that sheer number of them vastly counters ANY argument
>that gasoline-powered vehicle makers can claim, and they know this.  I
>believe that they are changing as fast as they possibly can for their very
>survival, but indeed, some of them may have waited too long to recover
>market share.
>
>Dan.
>
>
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