Hello!I'm curently doing very similar project.I was planning to use four independent mosfets and steering them with one PWM signal. The problem is that for one connected mosfet it works perfectly, but if I connect more mosfets it didn't.Anynone know what is the problem?I'm attaching the circuit
Perhaps someone could help if you described what not working perfectly actually means.Paul
Are those modules the ones with the IRF520 MOSFET? If so, be aware that they are not logic level MOSFETs and will not fully turn on with a 5V gate signal*. The FQP30N06L MOSFET that the OP linked in their first post is a much much better choice. *See the Rds(on) spec and Figure 3 in the IRF520 data sheet.
Can you post a data sheet for the Generator PWM? What are the specs of the 12V power supply (Volts, Amps)? What are the specs of the injectors? Those modules have no flyback diodes, the diodes need to be added.
Injector are high-ohm ones (14,5 ohm). Calculated current is about 0.8A and measured one is the same.In cicrciut "urz.1" and "urz.2" means injector + flyback diode - I should wrote that.Couldn't find manufacturer PDF, but here is specification of PWM generator:http://www.icstation.com/adjustable-square-rectangle-wave-signal-generator-module-channel-pulse-frequency-150khz-p-9668.htmlI have test it with multimeter and works fine - 50% duty cycle gives 2,5V, 100% gives 5V. Even withount PWM generator one mosfet works correct just by switching by connecting jumper-wire to 5V and. 12V comes from 33A industry power supply.
Don't forget you need a controlled high pressure fuel supply, and atomised fuel is extremely (as in extremely) combustable - so this can be a pretty hazardous experiment and a little 12v spark would make it even more exciting .You can look on line for a given injectors flow rate characteristic ,which is easier. Some injectors ( usually diesel) have a coding for their individual performance ( often loaded into the ECU when an injector is changed)If you don't use fuel remember a liquid of different density and viscosity will flow at a different ratelookie
A couple of things that might help:1) You can use hardware grade Mineral spirits for testing. It is very close to Stoddard solvent which is the industry standard for fuel system testing (not for every test but for 90% of the testing). Any error you might see between the Mineral spirits and gas is likely to be below your ability to measure.2) Unless this is going to be a short test, injectors like to see a full voltage pulse to open then a reduced current to stay open. see the below driver.fuel injector driver