[gregrob]

I see DDP uses LPM - Liters Per Minute.

That seems like A LOT of fuel, a litre every minute?

Seems it should be more like Litres Per Hour.


School me

 

[Charles]

Flow per time is a foolish way to try and measure a unit injector IMO.

All, I repeat, all, you can measure in this fashion are the actual nozzles. How can you relate flow per time to a Heui?

What if I did one minute but cycled the injector 1000times? What if I cycled it 50 times? 100?

You can only measure the injector's flow on a per unit basis.

Also, while I'm on the soapbox, most of these per time measures are made by flowing AIR though the nozzles... Totally different animal. A stopped up POS nozzle can actually flow rather well when passing air through it, and yet flow like ass when you actually try to push something massive like diesel fuel through it.

.02

 

[gregrob]

but you didn't answer my question oke:

Why LPM, instead of LPH?

Thanks for your input

 

[bigrpowr]

DDP measued my injectors at LPH...over 40...charles you should build injs too... man you know it all

 

[Haul_n_horses2]

DDP measued my injectors at LPH...over 40...charles you should build injs too... man you know it all

I think if you talk to Ross, you will find that those nozzles flow 40Lpm. It is not fuel it is air. It is the way they measure the EHD changes in the nozzles. OEM are 18+/- 1.5 lpm. Mine are lightly opened up and balanced at 21 +/- 0.5 lpm. BD are usually done at 29 lpm etc. It has nothing to do with the amount of fuel the piston will displace in a 1000 firing cycles.

As to Charles point it seems the industry standard is 1000 ejection events. But that would be in an ideal situation ie. enough time to fill, enough oil pressure to empty. Some will quote the denominator if it is different from 1000.

 

[Charles]

DDP measued my injectors at LPH...over 40...charles you should build injs too... man you know it all

With guys like you building trucks these days somebody's got to know how this stuff works otherwise who would you write the checks out to?



And no.....they did not measure your injectors in flow per time, they measured your nozzles. You cannot measure a unit injector in this way.

Let me rephrase.....it isn't foolish to measure a unit injector in flow per time, it's physically impossible. Is that clearer for the checkwriters on the forum?

:hehe:

 

[Tom S]

As long as later on they are testing the injector as it is assembled, what is wrong with checking the nozzle this way as a preliminary step?

Tom

 

[Charles]

Oh, absolutely nothing. Other than the fact that they're flowing air through it and not liquid, flow testing a nozzle like this is a great thing to do.

I'm just saying that this flow number has absolutely nothing to do with the injector's finished flow rate. Because it's a unit injector. It doesn't do anything per hour, or per minute, it's per injection event.

Basically, you've got an injection shop that has probably been doing diesel injectors since the begining of time. Now 99% of all injectors (diesel, gas, whatever) are just an orifice and valve. A nozzle. So you measure their flow at a standard pressure and time. And they have tried to apply this to a unit injector.

Wrong. All it tells you is the nozzle size.


For instance...... lets say we had a DDP nozzle rated at 29 LPM. So lets say we put that nozzle on a BD injector....

I think we can all see the potential of that injector. Now what if we put that nozzle on an AA injector?

According to their flow measurement system those two injectors ought to be the same... I mean, the LPM is exactly the same, right guys.

 

[bigrpowr]

With guys like you building trucks these days somebody's got to know how this stuff works otherwise who would you write the checks out to?



And no.....they did not measure your injectors in flow per time, they measured your nozzles. You cannot measure a unit injector in this way.

Let me rephrase.....it isn't foolish to measure a unit injector in flow per time, it's physically impossible. Is that clearer for the checkwriters on the forum?

:hehe:

good thing i didnt have to write a check for those injectors...sponsorship is a beautiful thing.

sorry i thought it was lph... whatever, they work.

 

[Stroked95]

SO for the checkwriters, like myself I guess, what is the ideal way to measure unit injectors? I have a guess but not sure. Once you know the correct flow what exactly does that tell you?

 

[Charles]

I have proposed many times that a standard be created.

I have stated that I would like to see 4ms pulsewidth, 2800psi ICP and 1000 shots.

That will give you a repeatable number to work with in CC's per 1000.

I personally do the same kind of test again at say 2ms pulsewidth, 1500psi ICP and 1000 shots.

This gives a nice look into how that injector is going to work at a part throttle situation, as the truck runs 99% of it's life. A junk nozzle will show up here.

That's the only reliable, and worthwhile method of describing an injector's qualitys that I know of.

JMHO

 

[roosterdiesel]

I have proposed many times that a standard be created.

I have stated that I would like to see 4ms pulsewidth, 2800psi ICP and 1000 shots.

That will give you a repeatable number to work with in CC's per 1000.

I personally do the same kind of test again at say 2ms pulsewidth, 1500psi ICP and 1000 shots.

This gives a nice look into how that injector is going to work at a part throttle situation, as the truck runs 99% of it's life. A junk nozzle will show up here.

That's the only reliable, and worthwhile method of describing an injector's qualitys that I know of.

JMHO

Hmmmm....wonder how Charles came up with that....Oh I know.
Injection pumps are calibrated the same way...CCs/1000 strokes. I have to set the Full load at spec'd RPM and then at idle RPM, then hopefully the torque run falls in which it does when overhauling a pump with good parts.

Our injectors are basically single injection pumps for each cylinder that use oil to get the pressure.

I would also like to see a standard.