# Fuel injector signal driving IGBT



## Zak650 (Sep 20, 2008)

Ok for an off the wall idea, could you use the car's 4 fuel injector signals to somehow drive IGBTs or some other device to arrive at a variable frequency drive. The motor would require a (flywheel, signal source) but use the car's ecu to coordinate the frequency drive. A 4 pole single phase motor would probably work best for this for the 4 sequential firing order.

Zak


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## piotrsko (Dec 9, 2007)

motor also needs a pulse source (that is some degree offset) so the computer knows when to fire injectors. Not a bad idea, but a wee bit hard to implement. Also the pulses vary according to rpm of motor, generally getting larger as rpm increases but not necessarily as loads increase, so a uncontrolled motor run away situation is possible here.


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## frodus (Apr 12, 2008)

you need a 4-phase motor, not single phase. Single wouldn't do anything. Poles has to do with how many magnetic poles the motor has and how fast it would go at a given frequency. You need 4 coils to fire sequentially, hence 4 phases.


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## hans j (Mar 31, 2008)

Try looking into Megasquirt fuel injection. VERY basic and can probably be setup to do what you want. If you can just get either a crank signal off the flywheel or use a hall effect pickup like what is in distributors, it could work. You will also need a separate throttle position sensor and some sort of tach pickup.

I run it on one of my VW rabbits and am only running fueling off of it. My only inputs are coolant temp, intake air temp, engine rpm and signal from the distributor. Outputs are fuel injectors.

I believe the new systems are even sequential for the injectors (mine is batch fire so it fires all the injectors at the same time).


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## Zak650 (Sep 20, 2008)

A single phase motor corresponds to a single sine wave, a three phase motor corresponds to three evenly spaced sine waves in the same time period. At 60 hz a two pole motor rotates at 3600 rpms and has two stator poles, a four pole motor operates at 1800 rpms and has four stator poles. 

My basic question is the modern car comes equiped with this modern smart ecu capable of firing fuel injectors in a speedy and accurate manner. In converting a car we throw away this whole system, why not keep it to drive the electronics. We just have to have devices on or attached to the electric motor that fools the ecu into thinking the ice is still in the car.

Whether its a AC system firing electronics to achieve alternating current or a DC system constructing a chopped sine wave it seems taking the 12 volt injector pulse should be able to drive an electronic transistor, mosfet, or igbt and drive an electric motor.

Zak


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## TigerNut (Dec 18, 2009)

If you want to pursue that for an AC motor then you should start with a 6-cylinder ECU. That way you'll have an appropriate number of drivers and the tach signaling will be at the right rate. 
ECUs regulate the injector pulse width based on air mass flow rate, not strictly the throttle opening; you would have to mess with the various sensor inputs to get the output to do what you want. Still, it's an intriguing idea especially if the ECU also controls things like the transmission.

ECUs can be had relatively cheaply at the autowreckers.


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## piotrsko (Dec 9, 2007)

and actually the IDM injector controller in my F250 diesel outputs about 120v at the injectors not a lot of current however.


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## Zak650 (Sep 20, 2008)

Thanks for the info on the injectors. I have a '94 civic that is the potential donor car and it seems a little easier to do a DC system, in the end using a Netgain Warp 9 motor. I also have a Honda CRX that is my beater car, 300,000 miles. I'm thinking of tapping into the injector leads and use these to experiment with while the car is running. Hopefully I'll be able to get a small dc motor to operate off these and then start scalling things up from there. If I can get a circuit to drive a 1 hp dc motor I have on the passenger seat as I drive along then the rest of it seems like a real possibility.

Zak


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## ACAUDI (Apr 27, 2012)

Hi 
You can try to replace the reading of the current at the IGBT phase output instade of the MAF for the ECU ,it may require an interface.
cheers


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