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'''Injector measurement''' I was interested in injector opening/closing time regarding to flyback setups. All of the below measurements made on a 12 Ohm Hi-Z injector dry -without fuel pressure-, and PowerFlyback installed inside the ECU. No PWM-ing was enabled, pulse width is ~14ms. '''NEWS 2007.01.26''' I did some measurements with setting cranking RPM range high. Basically it worked fine, but two problems arised: 1. Pulsewidth simply disappears (goes to zero) after some amount of time. Time's between ~40-120 seconds of "cranking". Sometimes it doesn't need to have RPM signal at all just change settings in megatune, and pw on LCD/megatune/in_reality changes to 0000. Switching off/on resolves the problem for the next ~100 seconds. 2. Above 20ms of cranking pw , scale gets really high. It's maybe by design. Megatune have difficulties displaying huge pw values. About the results: http://quasar.dynaweb.hu/~lezsi/vems/flowmeasure1.gif I'm not sure whether this is normal or not. I expected a linear growth of flow with pulsewidth (at least in the higher range). All of the above pulsewidth values includes all timing (I have set all open times to 0) ---- 2007.01.22 I've put together a flowbench-setup http://quasar.dynaweb.hu/~lezsi/vems/flowpad-small.jpg First tests showed that injector opening time increased slightly according to the fuel pressure introduced (3 bars). No flow measurement data yet. Question: How can I force GenBoard to a specific pulsewidth? -Tried "mxofemxofemxp05mxp05" and similar, but no effect at all. I would use a soundcard ElectronicDesign/TriggerSignalGenerator with 60-2 or similar pattern, and use "cranking RPM" (both low-temp and high-temp values set to same pulsewidth). you can bump up cranking_thresh, but best to apply 290 RPM or similar. Take care (and have multiple fire extinguishers at hand). -It good-and-working idea, thanks. ** You might want to measure (if measuring 'acutal' flow rate) at around 6000 1/min (ie. 100 Hz) or similar (depending your engine maximum revolutions etc.) and around 80-85 % opening time (ie. 8,0-8,5 ms at 100 Hz). //BengtR ** Good idea, I'll check it later, first I'm interested in the idle-area. ---- Voltage was 12.1-12.2V, voltage/current measurements were made after a 0.3Ohms resistance, so test setup is like: +12.2V____[0.3Ohms]____*Measurement*____[injector]____INJ-OUT The results: http://quasar.dynaweb.hu/~lezsi/vems/3flyback.gif Red channel means measurement voltage (or current). Blue channel means mechanical movement/noise. *1. graph is one open-hold-close pulse with '''no external flyback'''. Closing time is '''1.7ms''' *2. graph is similar open-hold-close pulse with '''18V Zener flyback'''. Closing time is '''~0.95ms''' *3. graph is similar open-hold-close pulse with '''30V transient diode flyback'''. Closing time is '''0.9ms''' -all of them includes internal PowerFlyback- It's visible on the red channel that after opening (about 1ms later) current has a pulsation which shows the movement of injector iron core. At the same time mechanical noise started (blue channel). At closing phase there's not visible current-pulse in red channel but a spike goes well over starting (+12V) voltage which is the inductive "kick-back" or flyback current. Blue channel's mechanical noise shows here the exact position of mechanical injector closing. As my movement/noise detection (knock sensor) was nearly installed on the injector it's coil slightly picked up injector current, so on the blue channel it's also visible when injector current switched on/off (a single spike before noise). http://quasar.dynaweb.hu/~lezsi/vems/inj_knock3.jpg
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