over travel switch

[Colin]

Just wanted to confirm something in the rules about the break over travel switch rule. This year it's changed and we are no longer aloud to use the ECU to cut power the rules say "The switch must be implemented with analog components"�. So I assume we can use relays instead, is this correct?
cheers

[Colin]

Just wanted to confirm something in the rules about the break over travel switch rule. This year it's changed and we are no longer aloud to use the ECU to cut power the rules say "The switch must be implemented with analog components"�. So I assume we can use relays instead, is this correct?
cheers

[Igor]

I haven't looked at the rule yet, but that seems to be a bit of a weird rule. A relay is by most definitions also a digital component, whereas you can break down a microprocessor into analog components. A better definition would be "implemented with discrete components" or "without the use of software".
I think they did mean you would be able to use relays, but better check with the rules committee first.

Igor

[BryanH]

Colin, wire the overtravel switch in series with +13.8V from ign switch and pin 86 of 2 relays(loop). one relay for fuel pump & ignitor and 2nd for injectors & coil. 85 pins to two pull to gnd outputs of your motec. set one to F.P. and #2 to engine control relay.
This complies with 2004 rules precisely.
Igor, relays are as anal. as it gets, take that rule book to bed tonight!

[Igor]

Halfast, since relays only have two positions they are about as digital as it gets http://fsae.com/groupee_common/emoticons/icon_wink.gif
And having the rule book in my bed really makes my girlfriend jealous, so I won't try that anymore....at least not at the same time http://fsae.com/groupee_common/emoticons/icon_rolleyes.gif

Igor

[Jon @ Electromotive, Inc.]

<BLOCKQUOTE class="ip-ubbcode-quote"><font size="-1">quote:</font><HR>Originally posted by Igor:
Halfast, since relays only have two positions they are about as digital as it gets http://fsae.com/groupee_common/emoticons/icon_wink.gif
<HR></BLOCKQUOTE>

Digital doesn't really mean ON or OFF persay, at least not in this case. The difference I take it to mean is mechanical vs. software or solid state. There are solid state relays that could be used, but i don't think I would recomend them becuase of their relatively low current carrying abaility.

It can't really be argued that software (the ECU) is anything but digital, but one could easily make that argument that a relay is analog without anyone putting up much fight. Basically they just don't want a digital sensor attached to the ECU controlling this safety feature.

[Colin]

Thanks for the help guys, as for the change in the rules my understanding of why is that there was problems with proving the system during tech if it goes into the ECU, i know we have had this problem before because are fuel pump doesn't turn on until the engine rotates and the standard test is to turn on the ignition and listen to see if the pump switches off when the over travel switch is hit
cheers