Comments: viewtopic.php?f=41&t=2404
The Plan
The plan is to gather a lot of data for a single pressure (whatever the regulator is setup for) at various voltages and drive methods. To achieve this I'll be using some old equipment that I built for making noise. My list of gear:
- 500w variac/autotransformer
- 500w 12V stepdown transformer and rectifier setup
- 1 Farad capacitor network with brass bus bars
- One truck battery with idling hotel attached to it
- Bosch 130lph pump as detailed in hotel thread
- Starion turbo TBI throttle and fuel rail/regulator
- Two unknown 1 ohm injectors that appear identical - let's prove that
- Four identical small GSXR600 injectors that it'd be nice to know the flow and dead time data for
- Four 6A FETs on a Jaguar 0.6-alpha board
- Various resistors to limit current through the FETs
- One can of asparagus spears :-p
- 10 litres of 91RON pump gas
- 30 litres of pure toluene
- Minimum current that will open the injector at nominal pressure
- Minimum current that will keep the injector open at nominal pressure
- 3D Table of dead time vs. battery voltage vs. drive resistance
- 3D table of opening time vs. battery voltage vs. drive resistance
- Injector flow at nominal pressure
- Non-linearities in flow at low pulsewidths
Method
In the past I gave Sim some bad advice and he got some average
data from this. Sorry Sim! This section is wrapped to your taste to
make up for my failing in that area. I plan to look at what I told him,
what he got, and figure out what the right approach is, and post
that here.
Aside from that, the fuel pump will be powered from the big battery
in the idling hotel under FreeEMS control, this will ensure consistent
pressure for all runs, regardless of voltage being fed to the injectors
under test.
The asparagus tin has smooth sides, and a nearly flat bottom. Due
to this I can calculate the precise volume from the internal diameter
and depth of fuel in the can and not worry about trying to read
graduations and find/buy fancy measuring cylinders, etc.
The variac will power the transformer which will fill the capacitors
which will power the injectors under test. Using this setup I can
generate a smooth and reliable voltage anywhere from about 18
down to 2 or 3 or so.
My voltage break points will be 6, 7, 8, 9, 10, 11, 12, 13, 14, and
15 volts. I'll use resistances of 2, 4, 8, 16, 32 ohms to start with,
and some intermediate values once I know the first value that fails
to get and/or hold the injector open.
I'll use a variety of pulse widths and pulse counts such that the
results of measuring fuel volumes can be plotted in neat curves
and used to calculate the dead time and flow rate for the given
circumstances in the particular test. More detail on this once I've
fully analysed what is required and where I failed last time.
This thread shall be locked for the time being, start a comments thread if you wish, otherwise I'll probably open it up after I've completed testing and posting.
EDIT: Someone did: viewtopic.php?f=41&t=2404
Fred.