Re: RPM-Sensing Fuel Enrichment Module

[Dan <dan@angband.org>]

On Tue, Apr 25, 2000 at 09:43:22PM -0700, archive@porknet.fdns.net wrote:
> Hi all,
> 
> I think most of us are aware of how simple it is to build a TT-style fuel
> enrichment module with just a relay and a resistor, but a lot of people
> have said that going wide open throttle below 3000 rpm or so will make the
> mixture too rich and bog down the engine.
> 
> So... I'm undertaking a personal project to design and build a fuel
> enrichment module that is disabled below 3000 rpm.

Been there, done that, bought the t-shirt.

www.angband.org/dan/fueler.html


 This also doubles as a
> project for my electronics class :) The planned design is as follows: tach
> signal is sent to a capacitor connected to ground, which in turn creates a
> voltage that will rise and fall with changes in the rate of pulses from
> the coil tach signal. Then, an op-amp is employed to compare this voltage
> and a voltage created with a potentiometer connected to +12v and switch a
> circuit when the signal voltage is greater than the potentiometer voltage.
> The circuit switches +12v to the relay coil, while the other side of the
> relay coil is a switched ground from the WOT switch. Then, the engine can
> be held at any desired rpm, for example 3000 rpm, and then a helper turns
> the potentiometer and holds the full throttle switch closed until the
> relay clicks and the device is set.

Or you could use a LM2907 which does this all internally for ya. :)

Dan

-- 
There are more love songs than anything else. If songs could 
force you to do something we'd all love one another.

		-- Frank Zappa.

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