Multiple fuel injectors
Multiple fuel injectors
(OP)
Don't ask why I'm asking this, but...
Can anyone point me to an example of a port injected gasoline engine that uses more than one injector per port? These may be in series (i.e. one before the other) or both located the same distance from the intake valve.
Can anyone point me to an example of a port injected gasoline engine that uses more than one injector per port? These may be in series (i.e. one before the other) or both located the same distance from the intake valve.
- Steve





RE: Multiple fuel injectors
Not exactly what you're after, but related:
h
Lexus gives V6 dual injection
The latest and most powerful member of Toyota's
GR-series V6 family, the 2GR-FSE, encompasses
the company's leading-edge injection gasoline
engine technology. As fitted to the Lexus IS350
and other Toyota models, it employs two (port
and direct) injectors per cylinder with new "double
vertical fan-shaped spray" to achieve a homogeneous
and dense fuel mist.
custom bike setup
http://www.rbracing-rsr.com/zx11tubo.htm
RB Racing only builds sophisticated state of the art systems that feature: ... custom throttle bodies w/2 injectors per port;
Honda bike setup
h
Dual Stage Fuel Injection (DSFI) system features two injectors per cylinder.
RE: Multiple fuel injectors
The Toyota one sounds reassuringly expensive. I didn't think anyone would employ both systems on a single engine!
The Honda one sounds a bit like their solution to a driveability problem. I wonder if the FSAE crowd use these engines??
- Steve
RE: Multiple fuel injectors
RE: Multiple fuel injectors
RE: Multiple fuel injectors
RE: Multiple fuel injectors
http://www.rx8club.com/showthread.php?t=150432
(But then again, it also has three intake ports per rotor).
RE: Multiple fuel injectors
RE: Multiple fuel injectors
Drag race engines with roots blowers normally put some fuel in above the blower to lubricate, cool and seal the rotors, then some into the port to fine tune distribution. As a general rule on American V8s they run carbies for petrol and mechanical fuel injection for alcohol, but they run EFI on smaller engines. The tendency not to run EFI on bigger engines is the limits imposed by fuel flow through the injectors and the need for costly multi injector systems. I am not saying no one does it, I a just pointing ut what the vast majority do and why.
Regards
Pat
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RE: Multiple fuel injectors
Cheers
I don't know anything but the people that do.
RE: Multiple fuel injectors
Current-production Honda CBR600RR is like this, to give but one example.
RE: Multiple fuel injectors
Cheers
Greg Locock
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RE: Multiple fuel injectors
Back in the bad old days, when EFI was new and large capacity injectors were not available, I tried my hand with a Haltec F1 with a wiring harness for sixteen injectors. It was a staged system, but the software was not able to handle the progressive transition. Not surprising it didn't survive.
thnx, jack vines
RE: Multiple fuel injectors
In my quest for ever increasing VE and greater boost pressures you soon find that the amount an injector can flow to the amount the stock ECU can control becomes an issue.
Say you have a turbo charged SAAB. ( my favorite) and on 94octane I can run 28lbs of boost with a 9.5-1CR. (I can and do)
The problem becomes in theory that for the amount of HP say 320HP I am supposed to run 46lbs injectors for the Inline 2.0L engine.
On standard Bosch 2.4LH the system can't handle the timing of the injectors though they are fired in batch.
So, the next step is to make(megasquirt) or buy an aftermarket that will control the injector.
This sounds good right. Well, with that large of injector you will have a hard time at idle to set it up and fuel MPG will suffer.
the next best solution is to keep the stock 24lbs injectors and add another further upstream pointed up the runner not down.
Use a throttle switch and pressure switch to control the on/off of the secondary injectors and just use the pulse signal from the main bank as the trigger signal for the secondary injectors. You can setup a small relay circuit for the secondary injectors.
Anyhow, in the next few months I am actually building such a system as a test bed for some parts I am producing. Should be interesting.
RE: Multiple fuel injectors
There are ECUs available that will control large injectors at idle.
RE: Multiple fuel injectors
I use 60 lb injectors on my 2.0 twincharged SVT Focus running upwards of 25 lbs of boost and I had perfectly good low load and idle fuel control using the a modified OEM ECU and later on using a Haltech E6X. I have lost economy but that is to be expected when adding a roots blower and a turbo.
Take a look at your fuel pressures and lower them if you don't need extra headroom. If you can flow enough fuel through your injectors at WOT and 45 PSI of fuel pressure, why keep fuel pressure at 60 PSI and decrease injector pulsewidth down to the point where the injector can't respond quick enough? So long as you still get a good spray pattern AND you don't max the injector out during peak fuel consumption, a lower fuel system pressure does nothing but increase your accuracy.
RE: Multiple fuel injectors
RE: Multiple fuel injectors
They have set-ups like mentioned above - octane on demand is what they call it.
RE: Multiple fuel injectors
Regards
Pat
See FAQ731-376: Eng-Tips.com Forum Policies for tips on use of eng-tips by professional engineers for professional engineers
RE: Multiple fuel injectors
- Steve
RE: Multiple fuel injectors
Unfortunately your OP was not that specific.
Now that you have specified, many of the above posts could be considered off topic from this point on.
Regards
Pat
See FAQ731-376: Eng-Tips.com Forum Policies for tips on use of eng-tips by professional engineers for professional engineers
RE: Multiple fuel injectors
- Steve
RE: Multiple fuel injectors
The Lexus system uses a typical intake runner injector, and the second injector is a direct injection system ( direct into the combustion chamber). This system makes use of a "stratified charge" for improved performance and emission standards.
One thing that never seems considered strongly enough is exactly how a technician is supposed to analyze a problem when a problem with a system like this finally occurs. I can easily envision individual cylinders suffering a fuel density missfire and only under specific engine load conditions. Which could mean, no way for the tech to re-create the conditions in the bay, and nothing but intuition to rely on for figuring out the problem with a customers vehicle. Sure some will say on-board diagnostics will show us what cylinder is miss firing and when, but truly almost everything else about the failure will be completely unknown. That amounts to too many variables that can only be worked through in lab type settings, where time isn't a factor. Meanwhile a technician is expected to diagnose the problem in a flat period of time, and then repair the circuit or change a part and always be correct the first time. That's a standard that if put to the test, NO-ONE could ever completely live up to.
RE: Multiple fuel injectors
So running 91 oct from one fuel cell on one set of injectors, and 116 from another fuel cell to the other set indicates, what, zilch on their credibility?
They may not be degree certified engineers, but their ingenuity is commendable - maybe not their tagline. I only quoted what they say.
Take a look at their products and then give an opinion.
Nevertheless, to run those injectors, if I remember right, they use Electromotive's TEC³. The guy wanted examples of engines running multiple injectors. DON'T be so quick to judge.
RE: Multiple fuel injectors
I just wasted another half hour not prejudging the Lets get edjumacated video. As expected after seeing the gloss and glitter preceding it, it was kindergarten level with a Las Vegas façade.
Regards
Pat
See FAQ731-376: Eng-Tips.com Forum Policies for tips on use of eng-tips by professional engineers for professional engineers
RE: Multiple fuel injectors
RE: Multiple fuel injectors