genesis 80fi injector deadtime

[kevfort]

hi, i am the engine guy this year. we tune our engine with an AEM ems-4 and we just found in the wizard that the last year guy put honda civic injector for deadtime table (injector pulse vs battery voltage table). we try to contact the manucfacturer of the injector ( Denso) with no answer.
I also search a lot on the web to find some data but no results.

Does a team has been able to find some data for the stock injectors?

Kevfort
Formula Sae UQAC

[Drew Price]

What are the genesis injectors? I imagine they will have very similar latencies (that's what we call it down here).

Are you having trouble getting the engine to run, or have you not gotten past just setting up parameters?

You might look for threads on the www.msefi.com (http://www.msefi.com) website. It's for Megasquirt, but has TONS of threads on specs for different off the shelf parts that people use for EFI swaps. I know I have seen injector latency tables on there, mostly for Bosch injectors, but probably also for Siemens and Denso injectors. Also lots of info on temp sensor ranges, throttle body sizes, stuff like that.

It's a handy resource if you're new to the engine tuning game.

[kevfort]

The injectors are Hight impedance (12.3-12.4 ohms), 240 or 260cc

We have the engine running at idle. We had tune the idle properly. The engine was starting like a charm. But the next day, when we try to start it, it just dont want a start anymore.

So we decide to return to the base, and make sure all the parameters are good. It's at this time we find that the last year guy put strange setting. And the two last year..the engine was running like an old grand-ma....

Thanks a lot for the msefi forum. It looks like it have a tons of informations.

[Cardriverx]

Formula Sae UQAC

Send the injectors to a cleaning company, they can usually do a lactancy test too.

[Drew Price]

Originally posted by Cardriverx:
.... they can usually do a lactancy test too.


???



http://scm-l3.technorati.com/11/10/21/54445/milk.jpg?t=20111021125120

[B Lewis @ PE Engine Management]

What is the P/N of the injector? We may have flowed these for dead times in the past.

[kevfort]

these are DENSO
it have two number on the injectors

6EGJF

the other side

0990 62518

Thanks a lot

[B Lewis @ PE Engine Management]

Sorry. I don't have those.

[kevfort]

thanks to had verify,


is it easy to mesure this deadtime?
like you all know, time is important and i don't want a lose this time if i'm able to have the data from the company but it's already does a week i'm waiting for this.

[kevfort]

I just received the answer of Denso,
They told me they are prohibited to give me this kind of informations as they developped these injectors with the manucfacturer...

[JWard]

This is a feature I really liked with the DTA ECU we used. There was a feature where the injectors would inject fuel twice on the suck part of the cycle, then back to once. You then played with dead time and fuel settings until you got the correct lamda for each type of setting. Very quick and easy way of working it out. (I may have the details slightly wrong, but you get the idea)

You may be able to get a good deal with a local tuning shop with the correct equipment. it's a simple and not very time consuming test for them to perform. It would also higlight any variablility between your injectors. Try calling around?

[Cardriverx]

Oh no, I accidentally revealed our secret feature for this year, direct milk injection!



Originally posted by Drew Price:
<BLOCKQUOTE class="ip-ubbcode-quote"><div class="ip-ubbcode-quote-title">quote:</div><div class="ip-ubbcode-quote-content">Originally posted by Cardriverx:
.... they can usually do a lactancy test too.


???



http://scm-l3.technorati.com/11/10/21/54445/milk.jpg?t=20111021125120 </div></BLOCKQUOTE>

[Moreboost]

This may sound odd to you, but check your big end bearings.

[kevfort]

this engine dont have bearing on the crankshaft..these are all journals bearings...

But why tcheck them? the engine last year was running good...by good i mean with no knocking sound..

[TurboTom]

kevfort

I think what Moreboost is trying to say is that the 80FI Genesis engine is very prone to serious scoring of their main bearings (engine failure) due to lubrication problems - Many universities running the 80FI have seens this problem at least once in their lifetime. This may be another cause for your motor not starting

[kevfort]

Hi,

Yesterday,we had started the engine after changing the one-way bearing. The bearing was slipping when we were starting..so the engine had not enough cranking force.

For the injectors, we decide to change them for 94 acura integra injectors that are 240cc hight impedance injectors, and all there datas are already in the ems-4

thanks

[Nicky]

IMHO, the easiest way to find the minimum dead-time of the injectors is to hook it up to a current driver and measure the current through the injector using a current clamp or a shunt.

The frequency on the driver must correspond to the maximum rpm you intend to run your engine at.
Eg:
Say 18000rpm max.
18000rpm/60=300rps
For a 4-stroke,
300rps/2=150Hz(Run the injector at this frequency)

Now while measuring the current on an oscilloscope, vary the duty-cycle, such that the current almost falls back to zero before starting out again during the next on cycle. The current through a 12ohm injector must fall at least to below 100mA(10% of Maximum current) before the starting off again in the next cycle. This duty cycle corresponds to the maximum allowable duty-cycle and the remaining time is the least dead-time that you can run.

It's best if the current driver is the ECU itself. The clipper/freewheeling circuits make a huge difference in decreasing the current decay time.

Voila, you have maximum duty-cycle and hence minimum dead-time of the injector.

Note: Don't run the injectors dry for long. And be sure to add some buffer time just in case. The duty-cycle that result from your fueling maps must not exceed this maximum duty-cycle, else you risk damaging the injector.

[Cardriverx]

When I refer to injector latency, I mean the dead time from power applied to the injector until actual fuel flow occurs, which will vary with voltage and fuel pressure. I assume the OP means this too, which is harder to measure because you need a flow bench setup (I guess you could take your intake off and just spray fuel...).

If you want to get more advanced then you need to measure the fuel output so that you can model the non-linear region of opening time vs flow. We use such small injectors tho that I don't worry about it.

What you are referring to is just the point at which the injector is essentially just open, or when the shutoff time is so quick the valve never closes. Usually this just occurs somewhere from 80-95 percent duty cycle depending on the injector. Also in my experience some injectors cope with 100% duty cycle just fine for at least a small amount of time as long as they have fuel in them.




Originally posted by Nicky:
IMHO, the easiest way to find the minimum dead-time of the injectors is to hook it up to a current driver and measure the current through the injector using a current clamp or a shunt.

The frequency on the driver must correspond to the maximum rpm you intend to run your engine at.
Eg:
Say 18000rpm max.
18000rpm/60=300rps
For a 4-stroke,
300rps/2=150Hz(Run the injector at this frequency)

Now while measuring the current on an oscilloscope, vary the duty-cycle, such that the current almost falls back to zero before starting out again during the next on cycle. The current through a 12ohm injector must fall at least to below 100mA(10% of Maximum current) before the starting off again in the next cycle. This duty cycle corresponds to the maximum allowable duty-cycle and the remaining time is the least dead-time that you can run.

It's best if the current driver is the ECU itself. The clipper/freewheeling circuits make a huge difference in decreasing the current decay time.

Voila, you have maximum duty-cycle and hence minimum dead-time of the injector.

Note: Don't run the injectors dry for long. And be sure to add some buffer time just in case. The duty-cycle that result from your fueling maps must not exceed this maximum duty-cycle, else you risk damaging the injector.