Fuel pressure / Flow rate formula

[d houlton x0710]

Bruce Plecan wrote:
> 
> 
> > It quotes RC Engineering and they 
> >apparently swear by the Lucas disk type injectors. 
> 
> I just wonder if they just happen to sell them.

Yup.  It does have the ring of marketing hype except that this isn't the
first I've read about the Lucas disk type injectors and their advantages
so I just more or less believed what they were saying.

Some other things were that the metering hole of the pintle types is at
the end of the injector whereas the disk type is more towards the center
of the injector surrounded by the injector's mass.  When you shut down an
engine, at least some of the exhaust and intake valves are open on the 
same cylinder letting the heat of the exhaust manifold back up and through
the cylinder to the injector in the port.  Pintle type tend to fry and 
boil the fuel at the tip gumming it up.  Disk type are recessed in the 
injector which also acts as a big heat sink so the effect isn't nearly as
bad.  They also pointed out it's much worse on turbo'd "V" engines.


>  They say they can run
> >at 85% - 95% duty cycle with no ill effects and can handle higher pressure
> >much better than the pintle type.  They can also run a much shorter pulse
> >at idle than a pintle type because of the smaller lift needed for a disk
> >type.  Something like a .8 - .9 ms opening time for the disk vs 2 ms or
> >so for the pintle.
> 
> They mention if they were Peak+Hold?.  

Hmm, don't remember if they did or not.  I don't think so, but they may
have mentioned the impedence so I'll check for that.


--Dan