Automotive EFI question

Oct 15, 2005 1 Replies

Hi all, I've got a question about driving the injectors in electronic fuel injection systems. Well, I watched the drive waveforms with an oscilloscope and found very high amplitude inductive flyback voltage-spikes during turn off of the injector. This is understandable, but my question is: Isn't it possible to add protection diodes across the injector coil, to eleminate the voltage spike, just like done in relaydrive circuits? Will such a diode affect the performance of the injector itself?



Best regards, Stefan Pls respond only to group, the e-mail adress doesn't exist!



Adding a diode WILL affect the performance. Instead of a very fast collapse of the magnetic field and quick closure of the injector you will get slow turn-off and excess "inject-time".

...Jim Thompson

| James E.Thompson, P.E. | mens | | Analog Innovations, Inc. | et | | Analog/Mixed-Signal ASIC\'s and Discrete Systems | manus | | Phoenix, Arizona Voice:(480)460-2350 | | | E-mail Address at Website Fax:(480)460-2142 | Brass Rat | | http://www.analog-innovations.com | 1962 | I love to cook with wine. Sometimes I even put it in the food.

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