Another injector question
Walter Sherwin
wsherwin at home.com
Sat Jan 27 01:11:56 GMT 2001
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Steve & James;
Here's a good primer for general injector tech pondering and background =
http://www.supras.com/~riemer/sonictech/fuel_injectors/RCtech.html . =
You'll probably want to discuss your particular project injector needs =
directly with vendors such as RC, Kinsler, Linder, etc., or even an OE =
injector manufacturer if you can make inroads to same (Siemens, Bosch, =
Delphi - the institutional/educational nature of your projects should =
enable this).
Injector packaging, impedance, internal pintle mass, spray pattern, and =
dynamic response issues are very real concerns that should be =
contemplated upfront in your designs to ensure that your injectors are =
compatible with both your end goals and your underlying hardware =
constraints.
The "static" flow rate of an injector is nothing more than the flow rate =
per unit time of liquid fuel through an injector while the solenoid is =
held at 100% duty cycle (always on), while the pressure differential is =
fixed at a prescribed value. Not very representative of the real world! =
The "dynamic" flow rate of an injector is simply the net flow per unit =
time that results from operating the same injector through real world =
open/hold solenoid duty cycle schedules. It physically takes time to =
open and close an injector, and the associated latent flow effects must =
be encompassed by your software in order to ensure proper step response =
of your EFI system. The latent effects for a given injector family will =
vary in response to fuel pressure, gross commanded ECU pulsewidth, and =
prevailing system voltage. Many OE EFI software packages include =
look-up tables that attempt to tailor ECU pulsewidths according to these =
these prevailing considerations. Response data can either be gleaned =
from manufacturer's data sheets for a given injector, or, may be =
empirically derived from a well instrumented injector test bench.
While precisely instrumented injector benches offer the truest measure =
of an injector's characteristics, it is also possible to arrive at =
reasonable approximations of same via more common (cheaper) benches as =
would be found in local fuel injection & diesel repair shops. Take a =
wander through your local yellow pages, and I'm sure you'll find a =
couple of shops that can oblige.
Have fun with your projects;
Walt.
----- Original Message -----=20
From: Steve Ruse=20
To: diy_efi at diy-efi.org=20
Sent: Wednesday, January 24, 2001 10:13 PM
Subject: Re: Another injector question
Hi, my name is Steve Ruse, and I am much in the same position as =
James. I am working on a fuel injection system for a Formula SAE car at =
LeTourneau University. I have a lot to learn, and this list looks like a =
great place to do that.=20
The engine is a 600cc four cyl from a Honda CBR. I also own a '94 Z28 =
and do custom EEPROM tuning on it, that is basically where I "cut my =
teeth" on EFI.
I am interested in the answer to James's last question, and I have =
also have some questions of my own.
First, what are some good sources for injectors? We have some for =
testing, but I don't think they are the ones that we will want to use in =
the end.=20
What is the best way to test the flow rate of our injectors? Is there =
something better than just timing how long it takes them to move a given =
amount of fuel?
Also, how can we account for the open/close delays of our injectors? =
Could that be accurately determined accurately by varying the duty cycle =
and seeing how the flow rate changes from when the injectors are at 100% =
duty cycle? Is there an easy way to keep our fuel pressure constant =
while performing this test? We were just going to try using an =
automotive fuel pressure regulator.
Thanks!
Steve Ruse
-----Original Message-----
From: james.drysdale at utoronto.ca <james.drysdale at utoronto.ca>
To: Fuel Inj Mailing List <diy_efi at diy-efi.org>
Date: Wednesday, January 24, 2001 2:35 PM
Subject: Another injector question: flow rates
Thanks for the responses to my previous question! (Even the ones from =
those=20
guys at Queens :)
Here's another: What's the difference between static and dynamic flow =
rates for=20
fuel injectors?
The spec sheet for my injectors lists both, but which should I use to =
calculate=20
the pulse width? (I'm thinking dynamic, but what's the difference?)
Thanks again,
james
"God help us. We're in the hands of engineers."
- from Jurassic Park
=
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To unsubscribe from diy_efi, send "unsubscribe diy_efi" (without the =
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<META http-equiv=3DContent-Type =
content=3Dtext/html;charset=3Diso-8859-1>
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<BODY bgColor=3D#ffffff>
<DIV><FONT size=3D2>Steve & James;</FONT></DIV>
<DIV><FONT size=3D2></FONT> </DIV>
<DIV><FONT size=3D2>Here's a good primer for general injector tech=20
pondering and background <A=20
href=3D"http://www.supras.com/~riemer/sonictech/fuel_injectors/RCtech.htm=
l">http://www.supras.com/~riemer/sonictech/fuel_injectors/RCtech.html</A>=
=20
. You'll probably want to discuss your particular project=20
injector needs directly with vendors such as RC, Kinsler, =
Linder,=20
etc., or even an OE injector manufacturer if you can make inroads to =
same=20
(Siemens, Bosch, Delphi - the institutional/educational nature of =
your=20
projects should enable this).</FONT></DIV>
<DIV><FONT size=3D2></FONT> </DIV>
<DIV><FONT size=3D2>Injector packaging, impedance, internal pintle=20
mass, spray pattern, and dynamic response issues are very real =
concerns=20
that should be contemplated upfront in your designs to ensure that your=20
injectors are compatible with both your end goals and your =
underlying=20
hardware constraints.</FONT></DIV>
<DIV> </DIV>
<DIV><FONT size=3D2>The "static" flow rate of an injector is nothing =
more than the=20
flow rate per unit time of liquid fuel through=20
an injector</FONT> <FONT size=3D2>while the solenoid is held =
at 100%=20
duty cycle (always on), while the pressure differential is fixed at =
a=20
prescribed value. Not very representative of the real world! =
The=20
"dynamic" flow rate of an injector is simply the net flow per unit time=20
that results from operating the same injector through real world =
open/hold=20
solenoid duty cycle schedules. It physically takes time =
to open and=20
close an injector, and the associated latent flow effects must =
be=20
encompassed by your software in order to ensure proper step =
response of=20
your EFI system. The latent effects for a given injector family =
will vary=20
in response to fuel pressure, gross commanded ECU =
pulsewidth, and=20
prevailing system voltage. Many OE EFI software packages =
include=20
look-up tables that attempt to tailor ECU pulsewidths according to these =
these prevailing considerations. Response data can either be =
gleaned=20
from manufacturer's data sheets for a given injector, or, may be =
empirically=20
derived from a well instrumented injector test bench.</FONT></DIV>
<DIV><FONT size=3D2></FONT> </DIV>
<DIV><FONT size=3D2>While precisely instrumented injector benches offer =
the truest=20
measure of an injector's characteristics, it is also possible to =
arrive at=20
reasonable approximations of same via more common (cheaper) benches as =
would be=20
found in local fuel injection & diesel repair shops. Take a =
wander=20
through your local yellow pages, and I'm sure you'll find a couple of =
shops that=20
can oblige.</FONT></DIV>
<DIV><FONT size=3D2></FONT> </DIV>
<DIV><FONT size=3D2>Have fun with your projects;</FONT></DIV>
<DIV><FONT size=3D2>Walt.</FONT></DIV>
<DIV><FONT size=3D2></FONT> </DIV>
<DIV><FONT size=3D2></FONT> </DIV>
<DIV><FONT size=3D2></FONT><FONT size=3D2></FONT> </DIV>
<DIV><FONT size=3D2></FONT> </DIV>
<DIV><FONT size=3D2></FONT> </DIV>
<DIV><FONT size=3D2></FONT> </DIV>
<BLOCKQUOTE=20
style=3D"PADDING-RIGHT: 0px; PADDING-LEFT: 5px; MARGIN-LEFT: 5px; =
BORDER-LEFT: #000000 2px solid; MARGIN-RIGHT: 0px">
<DIV style=3D"FONT: 10pt arial">----- Original Message ----- </DIV>
<DIV=20
style=3D"BACKGROUND: #e4e4e4; FONT: 10pt arial; font-color: =
black"><B>From:</B>=20
<A title=3Drusej at letu.edu href=3D"mailto:rusej at letu.edu">Steve =
Ruse</A> </DIV>
<DIV style=3D"FONT: 10pt arial"><B>To:</B> <A =
title=3Ddiy_efi at diy-efi.org=20
href=3D"mailto:diy_efi at diy-efi.org">diy_efi at diy-efi.org</A> </DIV>
<DIV style=3D"FONT: 10pt arial"><B>Sent:</B> Wednesday, January 24, =
2001 10:13=20
PM</DIV>
<DIV style=3D"FONT: 10pt arial"><B>Subject:</B> Re: Another injector=20
question</DIV>
<DIV><BR></DIV>
<DIV><FONT size=3D2>Hi, my name is Steve Ruse, and I am much in the =
same=20
position as James. I am working on a fuel injection system for a =
Formula SAE=20
car at LeTourneau University. I have a lot to learn, and this list =
looks like=20
a great place to do that. </FONT></DIV>
<DIV><FONT size=3D2></FONT> </DIV>
<DIV><FONT size=3D2>The engine is a 600cc four cyl from a Honda CBR. I =
also own=20
a '94 Z28 and do custom EEPROM tuning on it, that is basically where I =
"cut my=20
teeth" on EFI.</FONT></DIV>
<DIV><FONT size=3D2></FONT> </DIV>
<DIV><FONT size=3D2>I am interested in the answer to James's last =
question, and=20
I have also have some questions of my own.</FONT></DIV>
<DIV><FONT size=3D2></FONT> </DIV>
<DIV><FONT size=3D2>First, what are some good sources for injectors? =
We have=20
some for testing, but I don't think they are the ones that we will =
want to use=20
in the end. </FONT></DIV>
<DIV><FONT size=3D2></FONT> </DIV>
<DIV><FONT size=3D2>What is the best way to test the flow rate of our =
injectors?=20
Is there something better than just timing how long it takes them to =
move a=20
given amount of fuel?</FONT></DIV>
<DIV><FONT size=3D2></FONT> </DIV>
<DIV><FONT size=3D2>Also, how can we account for the open/close delays =
of our=20
injectors? Could that be accurately determined accurately by varying =
the duty=20
cycle and seeing how the flow rate changes from when the injectors are =
at 100%=20
duty cycle? </FONT><FONT size=3D2>Is there an easy way to keep our =
fuel pressure=20
constant while performing this test? We were just going to try using =
an=20
automotive fuel pressure regulator.</FONT></DIV>
<DIV> </DIV>
<DIV><FONT color=3D#000000 size=3D2>Thanks!</FONT></DIV>
<DIV><FONT color=3D#000000 size=3D2></FONT><FONT size=3D2>Steve =
Ruse</FONT></DIV>
<DIV><FONT size=3D2></FONT> </DIV>
<DIV> </DIV>
<DIV><FONT face=3DArial size=3D2>-----Original Message-----<BR>From: =
<A=20
=
href=3D"mailto:james.drysdale at utoronto.ca">james.drysdale at utoronto.ca</A>=
<<A=20
=
href=3D"mailto:james.drysdale at utoronto.ca">james.drysdale at utoronto.ca</A>=
><BR>To:=20
Fuel Inj Mailing List <<A=20
=
href=3D"mailto:diy_efi at diy-efi.org">diy_efi at diy-efi.org</A>><BR>Date: =
Wednesday, January 24, 2001 2:35 PM<BR>Subject: Another injector =
question:=20
flow rates<BR><BR></DIV></FONT><BR>Thanks for the responses to my =
previous=20
question! (Even the ones from those <BR>guys at Queens =
:)<BR><BR>Here's=20
another: What's the difference between static and dynamic flow rates =
for=20
<BR>fuel injectors?<BR><BR>The spec sheet for my injectors lists both, =
but=20
which should I use to calculate <BR>the pulse width? (I'm thinking =
dynamic,=20
but what's the difference?)<BR><BR><BR>Thanks=20
again,<BR><BR>james<BR><BR><BR>"God help us. We're in the hands of=20
engineers."<BR>- from Jurassic=20
=
Park<BR>-----------------------------------------------------------------=
-----------<BR>To=20
unsubscribe from diy_efi, send "unsubscribe diy_efi" (without the=20
quotes)<BR>in the body of a message (not the subject) to <A=20
=
href=3D"mailto:majordomo at lists.diy-efi.org">majordomo at lists.diy-efi.org</=
A><BR></BLOCKQUOTE></BODY></HTML>
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