Consultants say interference in vehicle electronics is possible
in [Technical]
|
From: Mark Olson on 26 Mar 2010 09:06 E. Meyer wrote: > On 3/25/10 8:52 PM, in article > 4-idndohTq_BjjHWnZ2dnUVZ_qWdnZ2d(a)giganews.com, "dr_jeff" <utz(a)msu.edu> > wrote: >> I am not saying that there weren't any cars that used engine speed >> rather than vehicle speed, but I would think that there are few. > Every car I have owned, starting with the 1960 Chrysler Imperial, has been > equiped with cruise control. They are/were all designed to regulate vehicle > speed, not engine speed. I can't remember any instance of a system that > attempted to regulate engine speed, though I do remember some aftermarket > kits in the 60's & 70's that were simple mechanical throttle controls. No one was claiming any factory cruise control worked by keeping engine speed fixed. Aftermarket cruise controls had that option though, and for cars with standard transmission it was a reasonable choice to tap off the coil signal rather than affix magnets to the driveshaft. The only down- side was if you set the cruise to 60 in 5th gear, and resumed in 4th you'd be doing 70 or so, depending on gear ratios.
From: Mark Olson on 26 Mar 2010 10:00 E. Meyer wrote: > On 3/26/10 8:06 AM, in article EZ-dnRV2qrn7LDHWnZ2dnUVZ_oGdnZ2d(a)posted.visi, > "Mark Olson" <olsonm(a)tiny.invalid> wrote: > >> E. Meyer wrote: >>> On 3/25/10 8:52 PM, in article >>> 4-idndohTq_BjjHWnZ2dnUVZ_qWdnZ2d(a)giganews.com, "dr_jeff" <utz(a)msu.edu> >>> wrote: >>>> I am not saying that there weren't any cars that used engine speed >>>> rather than vehicle speed, but I would think that there are few. >>> Every car I have owned, starting with the 1960 Chrysler Imperial, has been >>> equiped with cruise control. They are/were all designed to regulate vehicle >>> speed, not engine speed. I can't remember any instance of a system that >>> attempted to regulate engine speed, though I do remember some aftermarket >>> kits in the 60's & 70's that were simple mechanical throttle controls. >> No one was claiming any factory cruise control worked by keeping engine >> speed fixed. Aftermarket cruise controls had that option though, and for >> cars with standard transmission it was a reasonable choice to tap off the >> coil signal rather than affix magnets to the driveshaft. The only down- >> side was if you set the cruise to 60 in 5th gear, and resumed in 4th you'd >> be doing 70 or so, depending on gear ratios. >> > All the aftermarket kits (as well as factory add-on kits) I encountered for > manual shift cars all passed the speedometer cable through the unit for > speed sensing and added a second cut off to the clutch pedal (along with the > brake pedal cut off present on automatic trans units). I installed two kits such as I described in 1981 Dodge Colts, I can't remember the brand name, they had the option of putting magnets on the driveshaft (axle shaft in a FWD car) or picking the signal off the coil. I've also installed an Audiovox CCS-100 cruise control in a motorcycle, and it has the option of picking the speed signal off the coil or fitting a magnetic pickup to a driveshaft (not on a motorcycle obviously). installed a similar kit in a motorcycle
From: Scott Dorsey on 26 Mar 2010 11:46 Obveeus <Obveeus(a)aol.com> wrote: >"Scott Dorsey" <kludge(a)panix.com> wrote in message >news:hoh1a5$jpd$1(a)panix2.panix.com... >> In article <4babdcf1$1_2(a)news.tm.net.my>, TE Cheah <4ws(a)gmail.com> wrote: >>>15 yr ago I read of 1 car in USA using auto cruise control drtve >>>past a truck using CB radio, this car @ once got unintended >>>acceleration, this driver switched off his auto cruise & ended this >>>problem. He told medias to warn users of auto cruise control >>>against CB radios. >> >> It's not just cruise control... there are a huge number of trucks out on >> the road that are violating the FCC emission regulations by three orders >> of magnitude. Consequently anything that isn't very carefully shielded >> with proper grounding design can have serious problems. > >But if this was the real issue it would be much more easily detected and >repeatable. Yup. And because it's a serious and well-known issue, just about all cars sold in the US go through aggressive EMI testing. If only they would test other consumer products as well. Toyota is actually better about that than most manufacturers, although they issue a whole lot of warnings about not installing high power radio equipment in their cars and they won't provide support if you do. Contrast that with Ford, which has a whole support organization to help folks putting high power radio gear into fleet vehicles (mostly due to the police market). --scott -- "C'est un Nagra. C'est suisse, et tres, tres precis."
From: Scott Dorsey on 26 Mar 2010 11:49 dr_jeff <utz(a)msu.edu> wrote: >Wow! People are using CB radios with 12,000 W of power. That would >require a 1000 AMP alternator just for the radio (12 V x 1000 A = 12,000 >W). Note: the FCC limit is 12 W and 3 orders of magnitude is 1000 (10 x >10 x 10). Nope, FCC limit is FOUR watts. And I have sadly seen Alabama Pillboxes in the 6KW range. Really nasty output waveform too. And yes, they require a seperate alternator and aren't normally run off a 12V system. --scott -- "C'est un Nagra. C'est suisse, et tres, tres precis."
From: AJL on 26 Mar 2010 12:40
kludge(a)panix.com (Scott Dorsey) wrote: >dr_jeff <utz(a)msu.edu> wrote: >>Wow! People are using CB radios with 12,000 W of power. That would >>require a 1000 AMP alternator just for the radio (12 V x 1000 A = 12,000 >>W). Note: the FCC limit is 12 W and 3 orders of magnitude is 1000 (10 x >>10 x 10). > >Nope, FCC limit is FOUR watts. > >And I have sadly seen Alabama Pillboxes in the 6KW range. Really nasty >output waveform too. And yes, they require a seperate alternator and >aren't normally run off a 12V system. Hams (amateur radio operators) can legally run 1500 watts in the US. And many do so using homebrew mobile installations. At this power level if the installation is not done correctly the car electronics can not only malfunction but be damaged. But RF can be unpredictable and cause problems at low power also. I have had my cruise control affected with as little as 5 watts when using a VHF or UHF frequency (144, 220 or 440 MHz). Rerouting of cables and/or better grounding usually fixed it. |