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

HDi fun · 23-03-2008, 07:21 PM

1000rpm is 1000/60 per second, so 16.667 recurring per second.

Firing the injector 17 times a second is not going to work with a elecromagnetic relay I don't think. It will probably just bounce about between closed and open.

But then, the solenoid controlled injector is going to have to do 17 cycles per second and that doesn't suffer from bounce. Perhaps because of the enourmous fuel pressure holding it shut.

I think this has to be solid state in operation. Effectively were looking to get control of high current pulses of specific (and adjustable) duration.

The pulse width is as important as the timing of it.

For a single injector engine that's running at fixed speed under fixed load we can standardise the pulse duration. We can also fix the timing relative to TDC for this purpose.
And, err, I need to go away and think a bit more about circuit design.

23-03-2008, 07:21 PM	#17 (permalink)
HDi fun Moderator The Torque Meister Join Date: Apr 2006 Location: SOUTH EAST Posts: 1,393	Re: Two stroke diesel: Build a simple ECU ??? Do-able, or not? 1000rpm is 1000/60 per second, so 16.667 recurring per second. Firing the injector 17 times a second is not going to work with a elecromagnetic relay I don't think. It will probably just bounce about between closed and open. But then, the solenoid controlled injector is going to have to do 17 cycles per second and that doesn't suffer from bounce. Perhaps because of the enourmous fuel pressure holding it shut. I think this has to be solid state in operation. Effectively were looking to get control of high current pulses of specific (and adjustable) duration. The pulse width is as important as the timing of it. For a single injector engine that's running at fixed speed under fixed load we can standardise the pulse duration. We can also fix the timing relative to TDC for this purpose. And, err, I need to go away and think a bit more about circuit design.