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Topic: Fuel Injector Driver. (Read 464 times) previous topic - next topic

MarkT

That is a good MOSFET choice for your use.  It will fully turn on at 5V gate voltage.

You are missing the fkyback diode on the injector.  A high reverse voltage is generated when the injector is turned off.  Without the flyback, the MOSFET can be damaged.
Alas with a freewheel diode like this the injector probably won't run fast enough.  You need rapid turn off as
well as rapid turn on, so the reverse voltage on switch off must be allowed to rise, perhaps to 12V or more.

For this use a 12V zener and diode combination across the coil.

But best of all the datasheet for the injectors ought to specify the drive parameters for operation.
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rickerman

Alas with a freewheel diode like this the injector probably won't run fast enough.  You need rapid turn off as
well as rapid turn on, so the reverse voltage on switch off must be allowed to rise, perhaps to 12V or more.

For this use a 12V zener and diode combination across the coil.

But best of all the datasheet for the injectors ought to specify the drive parameters for operation.
Like this?



The service manual for the motorcycle does not mention the part number of the injectors and so I am struggling to find a datasheet for them.

MarkT

Nearly - gate driver chip is probably needed for accurate switch timing, but the zener snubber is right sort of thing.

BTW there are specialized injector driver chips for example LM1949 - datasheets for such chips are probably worth reading.
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