Torque Cars chat forums - View Single Post - Two stroke diesel: Build a simple ECU ??? Do-able, or not?

HDi fun · 20-03-2008, 06:34 PM

I think that the fuelling is controlled by pulse duration in nearly all cases, although lots of systems now have multiple injection phases. Eg - short pulse early pilot injection to get the fire underway. Then the main phase as close to TDC as possible. Sometimes you get one in the expansion phase as well for emission control systems that burn off soot actively.

(Incidentally, don't fire one of those injectors anywhere near hands or limbs - the delivery rate is so high that I've heard one case where one stuck open in a Peugeot 607 that it bored a hole into the piston crown.)

For experimental purposes I guess that you won't need this level of complexity.

Do you remember those kits you could get in the 1970's / 80's that converted your car with breaker points into one with electronic ignition? OK, the timing was still controlled mechanically but the switching was done solid state electronics (no points etc.)

These things could switch 10amps or so, repeatedly charging the igntion coil and breaking the circuit to fire the plugs. You need the opposite here, so......

If we could find a way to invert the pulse stream and amplify the curent this might give you a means of firing the injector. Timing was/is by means a magnetic reluctance device, so stick the magnet on the crank and the sensor somewhere adjacent; moving it about will let you change the timing.

Also, what are you going to use to supply the fuel under pressure. Even with a big flywheel I don't think a single cylinder motor will stand the compression load and the high pressure pump load. Still, if the flywheel was very very very big......But, then how do you get it spinning in the first place?

Cheers,

Regards,

Paul.

20-03-2008, 06:34 PM	#7 (permalink)
HDi fun Moderator The Torque Meister Car: Peugeot 406 Join Date: Apr 2006 Location: SOUTH EAST Posts: 1,745	Re: Two stroke diesel: Build a simple ECU ??? Do-able, or not? I think that the fuelling is controlled by pulse duration in nearly all cases, although lots of systems now have multiple injection phases. Eg - short pulse early pilot injection to get the fire underway. Then the main phase as close to TDC as possible. Sometimes you get one in the expansion phase as well for emission control systems that burn off soot actively. (Incidentally, don't fire one of those injectors anywhere near hands or limbs - the delivery rate is so high that I've heard one case where one stuck open in a Peugeot 607 that it bored a hole into the piston crown.) For experimental purposes I guess that you won't need this level of complexity. Do you remember those kits you could get in the 1970's / 80's that converted your car with breaker points into one with electronic ignition? OK, the timing was still controlled mechanically but the switching was done solid state electronics (no points etc.) These things could switch 10amps or so, repeatedly charging the igntion coil and breaking the circuit to fire the plugs. You need the opposite here, so...... If we could find a way to invert the pulse stream and amplify the curent this might give you a means of firing the injector. Timing was/is by means a magnetic reluctance device, so stick the magnet on the crank and the sensor somewhere adjacent; moving it about will let you change the timing. Also, what are you going to use to supply the fuel under pressure. Even with a big flywheel I don't think a single cylinder motor will stand the compression load and the high pressure pump load. Still, if the flywheel was very very very big......But, then how do you get it spinning in the first place? Cheers, Regards, Paul.