Just a quick question along those lines steveo - do you know, is the pulsewidth reported in the $EE datastream before of after this adder?
Your point is valid however - the operating range we're talking about here is going to be very rarely encountered for reasonably sized injectors.
Originally Posted by
steveo
if its a flow rate modifier cant you just scale the injector constant to bias the table?
No, you'd need to skew the entire offset table. The slope of the injector is assumed by the fueling equations to be a linear constant (even though it rarely is).
Edit: also, it's not a flow rate modifier. It's correcting delivered fuel mass for a region of the injectors flow curve that doesn't match the injector flow constant slope.
Though I'm scarcely qualified to teach a remedial course in fuel injection flow characterization, if I get bored enough I'll try to draw up a couple graphs to illustrate the difference between older type 1 / 2 knees and what a type 3 injector looks like. The graphs Fast355 referenced on injectordynamics are of type 3 injectors.
The topic I'm more interested in is how would you advise yoheer to proceed given the injector characterization posted here?
Code:
ACCEL 150136 - 36# Hr Fuel Injector Specifications
Drive Circuit: "Saturated", R-C Voltage Suppression, 14.0 VDC
Coil Resistance: 14.5 ohms
Fuel Compatibility: Standard Gasolines and Ethanol Flex Fuels
Fuel Pressure: 300 kPa (43.5 psi)
Static Flow Rate: 252 gm/min n-Heptane
Dynamic Flow Rate: 7.56 mg/pulse at 2.5 ms, 10 ms period (100 Hz)
Approximated Time Offset: 0.70 ms
Approximated Slope: 4.20 mg/ms
Minimum Linear PW: 1.38 ms
Linear Flow Range (SAE): 15.3
Opening Time: 1.35 ms
Closing Time: 0.67 ms
SMOV: 4.23 volts
Reply With Quote
Bookmarks