Changing injector pulse rate at idle?

[Craig Pugsley]

Hi people,

> Ed suggested :
> > 
> > Yet another technique is, of course, to use two injectors per
> > cylinder.  Use one small injector alone for the low-load stuff
> > and kick in the other at higher loads.
> > 
> 
> This is exactly the technique that we have resorted to for high flow
> rotary applications.  The injectors found on factory Mazda 13B efi
> motors are huge - they flow 2-3 times the volume of 'normal' injectors.
> Even so, this is not enough for race motors and turbo applications.
> We use two injectors per rotor with the second bank staged so that
> they are completly closed during idle and only start to open at higher
> loads.

Aaah.. Injected rotarys - now THAT grabs my interest :-)
This multi injector concept is going to be integral with the PP13B
project I'm working on... There's a huge range in the fuel flow for
these beasties.

Is the idea to have injectors of the same size, or a small & a big one?

Also, when it's in transition between single and dual injectors,how do
you split the time each one is on for?

EG
1. Does the primary injector increase in time, until it is 100% on &
   then the secondary inj progresses on from there.

OR
2. Does the primary injector handle light loads, then when a certain
   on time/duty cycle is reached, the secondary injector is run in 
   parallell with the primary (ie IDENTICAL timing)

Presumably in any situation with staged injectors the user would only
have to adjust the fuel 'on' time & they would be oblivious to how the
timing of multiple injectors per port is handled.

An ascii diagram might explain it the best.

Cheers,
Craig.