This is a demonstration of the fuel injector action of the 2011 and above general motors
Duramax diesel pickup trucks these engines use the new hazel fuel injectors which are very quick to
react and can inject multiple pulses of fuel into the cylinder / combustion event these piezo fuel
injectors run on as high as 250 volts and 20 amps and unlike the traditional fuel injectors that
we've used in the past which are electromagnetic these are not electromagnetic these this piece out
of the fuel injector itself has a stack of little by ezel wafers that we're not sure how many you're
in there but they're they're stacked up on top of each other like a bunch of little disks and
then we have power and ground wires connected at the top here and it's the function of this piezo
crystal stack to open the fuel injector nozzle and allow fuels going to the engine and like
I said it can be done very quickly up to seven or more times per combustion event can fuel be
finely atomized and sprayed into the combustion chamber which adds more power to the engine it's
cleaner burning and you get better fuel economy also so we've taken this basil crystal stack out
of the fuel injector body itself and what we're going to do is clamp it into a vise you can see
back here that we're going to hook to a dial indicator and apply a voltage up to 250 volts
to this puzzle fuel injector stack and see how far the plunger actually moves because this is
a solid-state device there are no moving parts but the by ezel crystals flex when they have a
voltage applied to them and that will push on the plunger of the stack right here and allow
fuel to leave the fuel injector nozzle itself so I'm going to clamp this into some nice soft jaws
into the vise so I've got this adapter here for the device to have the jaws be nice and soft and
I'm going to carefully clamp that into place and then let me bring the camera in a little closer
and you can see that the tip of the fuel injector pile crystal stack is touching the bottom of this
dial indicator now this dial indicator measures in the ten thousandth of an inch movement and let me
position the camera just a little bit farther over so we can get a better view of the dial indicator
we've got zero at the top here that one over there is one thousandth of an inch let me zoom in
so right here is zero the one right over here is one thousandth of an inch everything in between is
ten thousandths of an inch one ten thousandth of an inch and so I'm going to try to zero the dial
indicator with the fuel injector with the zero up to the top there we go it's close back it off just
a little bit more it's very touchy all right that's close enough we'll get zero right there
and so we are looking once again we're going to measure the travel of this pile spelled piee like
pi and then Z oh it's pronounced pi e so I was taught years ago to say piezo but it's apparently
it's PI easel and we are measuring on the top of the fuel injector pile crystal stack and so we are
looking at the dial indicator here now zoom out here a little bit then I'm going to take a fluke
multimeter that we have this is a special fluke meter it's called an insulation tester and it's
their model of 1587 we use it to check for loss of isolation on hybrid electric high voltage battery
systems and if you'll notice it has an insulation test button right there and a test voltage range
button over here and then on the dial we have a setting for 50 volts through a thousand volts of
insulation test and what this is is it's basically a mega ohm meter it's to measure really high
resistances and this can measure up to 2.2 Giga ohms resistance but what we're going to use it
for is not necessarily to measure the resistance of the fuel injector pH by e0 stack but to use
the various voltages to measure how far the stack actually moves and so what happens is the meter
itself like any old meter will actually apply a voltage to whatever it's wanting to know the
resistance of and then measure the current that goes through the circuit which is how ohm meters
work and then using Ohm's law where the current or the voltage divided by the current is the
resistance it comes up with the resistance well this meter can apply several different voltage
reign or voltages to the PI easel stack here and remember the general motors Duramax fuel injection
system runs on up to 250 volts but it does not have to use all 250 volts if it doesn't want to
so right now on the screen it reads 250 volts but if I hit the range button now it's showing 500 now
showing 1000 now it's showing 50 we're going to start with 50 volts and watch the dial indicator
move 10 thousandths of an inch is so touchy and to apply a voltage with this insulation
tester meter there's a button on the meter leave itself down there on the fender cover or there's
an insulation test button right here I'm just going to push and hold this button notice the
dial indicator moved about to 10 thousandths of an inch it shows here on the screen that we've got
55 million ohms and we've applied 56 volts DC in the bottom right hand corner so I let go of that
we'll go to the next fire range 100 volts notice the stack did not come back to 0 so I'm going to
Reesie row it okay there we go at 100 volts let's try that now it looks like it moved about 7 10
thousandths of an inch and it's applying 108 volts and add 108 volts it has about let's jump around
110 mega ohms of resistance so now we're going to take it up to the 250 volt range zero that again
250 volts which is the maximum that the engine control module for the Duramax is going to apply
and the ECM the engine control module applies the voltage and controls the ground so let's
see how far it moves at 250 volts looks like we moved of two thousandths of an inch or twenty ten
thousandths of an inch and that's 265 volts about 77 million ohms is what we get notice
it snaps right back to zero at that point and then just for experimentation purposes we're
going to go with even a higher voltage than what is used on the vehicle 500 volts let's
see what it does there looks like we get three and two ten thousand three thousandths of an
inch so thirty-two ten thousandths of an inch at 528 volts at 136 million ohms so we'll let
go of that and we'll go to the last one which is 1000 volts get this zero again
which of course a thousand volts is four times higher than it actually runs on but
let's see what happens thousand volts looks like it didn't like it so this has been a
demonstration of the piezo crystal stack movement inside of the new 2011 out of
aGeneral Motors Duramax engine very fast reacting fuel injectors almost everybody is using these
newer style fuel injectors now to meet the new tier 4 emission standards but certainly
a byproduct of that is more power and better fuel economy and of course cleaner emissions