[Diy_efi] 555 Timer controlled EFI, summary of off list messages - long
Geoff Harrison
geoff_h
Fri Jan 20 05:14:46 UTC 2006
Hi All. This is a summary of "off list" discussions, incuding
some 12 months ago, for ref.
The only reason they were off list, was due to attachments. If
any one still wants drawings,
and they are not on the DIY-EFI site, let me know, and I will
forward such.
Geoff H
>From John Smith 2 Jan 06
I have been trying to find info on setting up a PC-based or
scatch-built
analog EFI system for weeks now. So far I have come up empty.
This place is
the nearest I'v come to a solution. I looked through the
archives before
subscribing and the handful of relevant threads I found fizzled
before
concluding(9 months ago). I have two main questions of my own:
What happened to Al Lipper's PC-based and 8051-based projects
and all the
associated files? I know a server problem fragged them or
somethingbut didnt
someone somewhere have a copy or mirror it?
What about a simple 555 chip based injector controller? I saw a
few
references, but they quickly shifted focus to digital.
This EFI would be used as a universal testing tool for multiple
engines, but
initially it will be used on a single cylinder turbocharged
engine.
>From John Smith 2 Jan 06
OK, I found most of the PC-based stuff on a university FTP
server somewhere
in Cananda, but the 8051 is still MIA as well as the 555 chip
info. Upon
seeing the schematics for the PC method's adapter hardware, I've
decided to
focus on the simpler analog method. Does anyone recommendations
for this? I
need the system to be able to richen the mixture based on
manifold
pressure(turbocharged). It does not need EGO.
Also, if I can do it, I am also considering using an OEM ecu and
retrofitting it for a single cylinder. Would a GM-based unit be
better than
any other?
>From Geoff Harrison 13 Jan 06.
John,
I had a look at using a 555 timer some time ago. My ideas were
for a multi cyl, using GM sensors. And an o2 sensor to provide
feed back to close the loop.
If your still interested I could email block diagrams etc. I
must stress however, the ideas have
not been put into practise yet.
Geoff
>From Andrew Hopton 15 Jan 06
Hey Geoff, I have had some thoughts along these lines too, and I
would
love to see your stuff.
Andrew.
>From Geoff Harrison, a summary of posts 12 months ago, for those
who missed them.
Geoff Harrison wrote:
> Hi Andrew, sent this lot off to your old optusnet a/c.
>
> Still looking for updated drawings, showing all the
> sensors/transducers
> and FET o/p to injectors.
>
> Geoff
> ------------------------------------------------------------------------
>
> Subject:
> Re Analogue EFI
> From:
> "Geoff Harrison" <geoff_h at smartchat.net.au>
> Date:
> Sun, 15 Jan 2006 22:33:30 +1100
> To:
> "Andrew Hopton" <ahopton at optusnet.com.au>
>
> To:
> "Andrew Hopton" <ahopton at optusnet.com.au>
>
>
> Hi Andrew,
>
> This is the basic idea. The 555 is the block in the centre. I
> Have other
> drawings to follow.
> One reason why I haven't pursued the idea is that if you use
> GM
> transducers, you may as well use
> the GM harness, so why not use the GM controller. Start with
> an EPROM
> from an engine close to what you
> are building, and remap as required.
>
> It does have merit though, tuning with a screwdriver is
> quicker than
> burning EPROM's.
>
> Cheers,
> Geoff.
>
> PS that was a good link re the 700R4s. Lots of people think
> they are
> crap cause they know the feel
> of a trimatic or BW. Mine aint so bad after all.
>
> Subject:
> Emailing: 555 controller.GIF
> From:
> "Geoff Harrison" <geoff_h at smartchat.net.au>
> Date:
> Sun, 15 Jan 2006 22:46:32 +1100
> To:
> "Andrew Hopton" <ahopton at optusnet.com.au>
>
> To:
> "Andrew Hopton" <ahopton at optusnet.com.au>
>
>
> Nothing new in this bit! I can't find the latest drawing.
>
> If you have a look at the 555 timer, you will see the
> resistive part of
> the time constant
> goes to B+. All the engine sensors go to ground. The TPS could
> be
> rewired, however
> I wanted to "adjust" that value for temp (cold start in
> particular)
>
> Geoff
> ------------------------------------------------------------------------
>
>
> ------------------------------------------------------------------------
>
> Subject:
> Fw: [Diy_efi] 555 timers
> From:
> "Geoff Harrison" <geoff_h at smartchat.net.au>
> Date:
> Sun, 15 Jan 2006 23:20:26 +1100
> To:
> "Andrew Hopton" <ahopton at optusnet.com.au>
>
> To:
> "Andrew Hopton" <ahopton at optusnet.com.au>
>
>
> Andrew, there are some good points in this post made some time
> ago.
> (something went wrong with the list - we had our own little
> thing going)
>
> To trigger the 555, from a Kettering ign system, a toroidal
> transformer
> with 22t on the secondary, and 1 turn on the primary, will
> give a pulse
> of about 0.2 volts. This was tried on my wife's Barina of all
> things.
> The primary winding is the B+ lead on the ign coil, passed
> through the
> toroid once. In reality, you need 40-50 turns on the secondary
> to switch
> a transistor amp to feed to the 555.
>
> Geoff
> ----- Original Message ----- From: "Daniel Nicoson"
> <A6intruder at adelphia.net>
> To: "DIY_ EFI" <diy_efi at diy-efi.org>
> Sent: Tuesday, January 25, 2005 3:31 AM
> Subject: FW: [Diy_efi] 555 timers
>
>
>> We had some off-line discussion while the list was down for a
>> few
>> days. I
>> will post all of those exchanges incase others want to jump
>> in.
>> Thanks for getting us back online Steve!
>>
>> Dan Nicoson
>>
>>
>> -----Original Message-----
>> From: Daniel Nicoson [mailto:A6intruder at adelphia.net]
>> Sent: Wednesday, January 19, 2005 10:08 AM
>> To: A list for Do-It-Yourself EFI
>> Subject: RE: [Diy_efi] 555 timers
>>
>>
>> James,
>>
>> I've been thinking about your project of a bare-bones EFI
>> system. I
>> was one
>> of the ones that suggested a 555 timer based system.
>>
>> First, I wouldn't totally rule out your original route of a
>> blow-through
>> system. Check in on the Yahoo groups Jyturbo. Some of those
>> guys
>> have some
>> blow-through experience and may be able to help you
>> troubleshoot. In
>> fact I
>> think there is another turbo Yugo there.
>>
>> I say don't rule out the blow-through carb setup because the
>> 555 based
>> EFI
>> system will take some real time to work out well enough to
>> run a
>> turbo. Not
>> that it can't be done, but it is a whole project of its own.
>> (A VERY cool
>> project!)
>>
>> If you want to pursue the 555 EFI here are some thoughts:
>>
>> First, how much fuel do you need to deliver? Will the
>> injector you have
>> selected even start to deliver that much fuel? figure if
>> your engine
>> makes
>> 90 Hp stock (I know NOTHING about Yugos), 7-8 psi typically
>> gives 40-50%
>> increase, so you would make roughly 130 Hp on boost. So if
>> you use
>> brake-specific-fuel-consumption (BSFC) of .55(lbs/hphr) then
>> you will use
>> .55*130 = 71.5 lbs per hour. That's a pretty good rate for a
>> single
>> injector. A typical early 1990's Ford V-8 injector was
>> 14#/hr, Mustangs
>> used 19#/hr. These are cheap and plentiful in JY's. Use
>> several if
>> needed.
>>
>> Pulse Widths etc. I realize you are trying to set up a
>> throttle body
>> style
>> injector (like a carb). But pulse width limitations will
>> still apply
>> regardless of your final injector configuration. For each
>> revolution
>> of the
>> crank you must achieve 1/2 of your fueling. At 6,000 RPM a 4
>> cycle
>> engine
>> has 20ms (micro seconds) to inject fuel at 100% duty cycle,
>> 4,000 RPM
>> brings
>> that max pulse width to 30ms. Most injectors take from .5 to
>> 2.0 ms to
>> fully open (this takes away from useable max pulse width).
>>
>> Google is your friend learning about the 555 timer. Here are
>> some
>> links I
>> have found very helpful:
>>
>> http://casemods.pointofnoreturn.org/pwm/circuit2.html
>>
>> http://www.williamson-labs.com/480_555.htm
>>
>> http://home.cogeco.ca/~rpaisley4/LM555.html
>>
>> http://www.robietherobot.com/storm/mapsensor.htm
>>
>> http://www.digikey.com/
>>
>>
>> You started asking specific questions about current, voltages
>> etc on the
>> 555. Go to Digi-Key and pull down the product data sheet for
>> the
>> specific
>> chip you have. Although most 555 chips function the same
>> (logically)
>> different models have different specifications. These data
>> sheets ARE
>> your
>> friend. Also, some contain good application notes with
>> example circuits.
>> Pull down the data sheets from several different
>> manufacturers.
>>
>> I have been thinking about the overall function of what you
>> are trying to
>> do. I would set this up as a "load-based" TB EFI. As
>> someone else
>> pointed
>> out you can't do this purely on RPM. I would consider adding
>> a MAP
>> sensor
>> such as the MPXA4250A series (find it in Digi-Key, $18.00) or
>> find a MAP
>> sensor out of a junk car that puts out 0 - 5 volts.
>>
>> Think of LOAD as follows: Drive your car in second gear,
>> 3,000 RPM
>> steady
>> speed. That is a very light load. Now from that steady
>> state, floor
>> it and
>> you will experience high LOAD. Same RPM very different fuel
>> requirements.
>> On my 1994 Mustang GT, the light load situation would require
>> 2.5ms pulse
>> widths, full load would require 12.5ms pulse widths.
>>
>> You'll hear us discussing pulse width modulation a lot with
>> regard to
>> this
>> project. The typical way of doing this on a 555 is by
>> changing the
>> resistance and/or capacitance. There are some real
>> limitations to this
>> method, especially achieving full range 0-100% duty cycle.
>> The first link
>> above has a very interesting way to fully achieve 0 - 100%
>> duty
>> cycle. They
>> use a few more components but get a well controlled circuit.
>>
>> Here's how I would approach this project. TB injectors
>> sufficient to
>> flow
>> the fuel needed. Batch fire these injectors. On the 555
>> control
>> circuit,
>> set the 555 up as a "one-shot" or mono-stable circuit with
>> about a 45ms
>> pulse length (120K or so resistance & .1uF capacitor) trigger
>> it off the
>> primary side of the ignition coil (good luck dealing with the
>> inductive
>> spike - another whole subject...) then modulate the pulse
>> width via
>> the MAP
>> signal (using the ideas in the first link). You'll probably
>> need an
>> opamp or
>> two to set gain of the MAP signal etc.
>>
>> So basically if you open the throttle, the MAP sensor will
>> notice the
>> change
>> in manifold pressure and output a different signal which
>> changes the fuel
>> pulse width.
>>
>> For the injector drive part of the circuit take a look at the
>> LM1949 chip
>> (Digi-Key). It has a nice layout of an injector drive
>> circuit for a low
>> impedance injector. This is a good starting point.
>>
>> Final point. This project will not be easy to develop
>> without an
>> oscilloscope. I started my project without one and found
>> very quickly
>> I HAD
>> to have one. I wouldn't consider this EFI project without
>> one. This EFI
>> project is more involved than my own which I am 1.5 years
>> into (a
>> secondary
>> sequential injector driver). I'm currently re-working my
>> circuit to
>> make it
>> more simple (www.myo-p.com).
>>
>> Good luck with this project.
>>
>>
>> Dan Nicoson
>>
>>
>> -----Original Message-----
>> From: diy_efi-bounces at diy-efi.org
>> [mailto:diy_efi-bounces at diy-efi.org]On
>> Behalf Of James Seabolt
>> Sent: Tuesday, January 18, 2005 8:01 AM
>> To: diy_efi at diy-efi.org
>> Subject: [Diy_efi] 555 timers
>>
>>
>>
>>
>>
>> You guys got me thinking over the weekend and I think I'm
>> going to give
>> this 555 timer a shot.
>> I've had some experience with this chip. I built a timer that
>> would
>> turn an
>> LED on and off and when I was looking through an old shoe
>> box, found the
>> circuit still hooked up to the breadboard. That was almost 15
>> years ago!
>>
>> It's been so long since my Tech School days so I'm hoping
>> someone will
>> refresh my memory. If I can put anything to use from my
>> Digital Circuits
>> class, I'm hoping this will be it. Since I was unable to use
>> my computer
>> degree. I ended up working at a chemical plant instead after
>> school.
>>
>> What I want to do is take the tach signal from the - side of
>> the coil
>> which
>> will be the trigger, feed that into the 555 chip which will
>> pulse the
>> injector. And use a potentiometer to adjust the pulse rate.
>>
>> I want to start out using a Bosch cold start valve since it
>> would be
>> easier
>> to mount. Perhaps use the throttle position switch to trigger
>> a second
>> injector under wide open throttle and boost.
>>
>> I downloaded some pages on the 555 timer but can't figure out
>> what size
>> capacitors I need. And what range the potentiometer needs to
>> be.
>>
>> The timer chip I have is stamped NE555N. Is this the chip
>> that will
>> tolerate 5 to 18 volts? Or do I need a different chip?
>>
>> Also I'm a bit confused on the reset (pin #4). One schematic
>> shows it
>> tied
>> to pin #8 (Vcc). Another one shows something else.
>>
>> If someone could draw me up a schematic with what components
>> I need that
>> would be really cool!
>>
>> I'm off for the next three days (I work 12 hour shifts) and
>> would like to
>> spend time on my Yugo since it's too cold to do anything else
>> this
>> time of
>> year.
>>
>> Is it possible to build a working fuel injection system by
>> simply
>> controlling the injector using just a tach signal? I know it
>> probably
>> wouldn't be able to adapt any better to temperature and
>> altitude changes
>> than a carburetor but I'm thinking it just might work.
>>
>> I'm having my doubts whether I am going to successful at
>> getting my
>> Yugo to
>> accept blowing through a carburetor so I'm looking toward
>> fuel injection.
>>
>>
>> James Seabolt
>> Tennessee, United States
>> Homepage --->>> http://users.chartertn.net/jseabolt/
>>
>> 2003 Subaru Baja
>> 1987 Yugo GV
>> 1980 FIAT 2000 "TURBO" Spider
>> 1968 Ford Fairlane 500 (Not a Ford Galaxie!!)
>>
>> _______________________________________________
>> diy_efi mailing list
>> diy_efi at diy-efi.org
>> http://lists.diy-efi.org/mailman/listinfo/diy_efi
>>
>> _______________________________________________
>> diy_efi mailing list
>> diy_efi at diy-efi.org
>> http://lists.diy-efi.org/mailman/listinfo/diy_efi
>>
>
> ------------------------------------------------------------------------
>
> Subject:
> Fw: [Diy_efi] Re:555 Timers
> From:
> "Geoff Harrison" <geoff_h at smartchat.net.au>
> Date:
> Sun, 15 Jan 2006 23:22:01 +1100
> To:
> "Andrew Hopton" <ahopton at optusnet.com.au>
>
> To:
> "Andrew Hopton" <ahopton at optusnet.com.au>
>
>
>
> Geoff Harrison
>
> ----- Original Message ----- From: "Geoff Harrison"
> <geoff_h at smartchat.net.au>
> To: <diy_efi at diy-efi.org>
> Sent: Wednesday, January 26, 2005 3:28 PM
> Subject: [Diy_efi] Re:555 Timers
>
>
>> Tried an idea for getting timing pulses for timer controlled
>> EFI today.
>> Used a ferrite toroidal core with 23 turns of 16 AWG wire out
>> of the
>> junk box.
>> The B+ lead to the ign coil passed through the core once. The
>> pulse I got
>> looks good. 200mV with fast rise time, falling exponentially
>> back to zero
>> with slight ringing. The rise is due to the coil being
>> energised, the
>> ringing I suspect
>> as the plug fires. The core has an OD of 1", ID 1/2" and 1/2"
>> thick.
>> Its original
>> line of duty was AC mains filtering, so its only a low
>> frequency type,
>> and should be
>> available from Tandy/Radio Shack and similar outlets.
>> Remember the pulse occurs way BTDC, when the points close,
>> not open.
>> It has no
>> loading effect on ign circuits, or electronic tachos when
>> fitted. I
>> doubt that the series
>> inductance would have an effect on Ign, its probably less
>> than the
>> wiring back to battery.
>> If a bigger pulse is required, just increase the turns, i.e.
>> 10mV per
>> turn.
>> If the pulse is going the wrong way, just reverse the
>> connections.
>> BTW, the test vehicle was wife's Suzuki 1300. She's worried I
>> had it
>> hooked up
>> to the cro. I told her it needed defribulating.
>>
>> Geoff Harrison >> diy_efi mailing list
>> diy_efi at diy-efi.org
>> http://lists.diy-efi.org/mailman/listinfo/diy_efi
>>
Thanks, Geoff. Looking forward to wading in ...
Cheers.
>From John Smith 16 Jan 06
Really? That would be great! I just put together a 555
monostable with a
TIP3055 transistor on the output and it triggers an injector
just fine with
only a 9v battery. I'm looking to either use a manifold pressure
or mass
airflow sensor to control the width. I already have the mass
air...
>From Mark Krawczuk 16 Jan 2006
hi, i dont know that much about electronics, but would it help
having a
faster switching transistor ?
mark k
>From SK Rahman 16 Jan 2006
Hello,
I saw your post in the DIY-EFI list about a simple 555 based
EFI.
Since long been planning to do el-simple EFI for a 150 CC
engine. I
would be glad if you can send me the some information (block
diagram
etc)
Sorry for the personal mail though
Regards
>From SK Rahman 16 Jan 06
On 1/16/06, Geoff Harrison <geoff_h at smartchat.net.au> wrote:
> Hi, wade through this lot.
> A problem you may have is getting the injectors to fire
> several
> times per rev.
> If you can get sufficient fuel on one "shot" per rev, you're
> on
> the way.
> If its a two stroke, no problem.
Thank you Geoff,
Once I have concrete plans I will start posting in the list.
In the mean time just thought of taking our opinion on the this.
To start with
1) I am not sure why the injector needs to fire several times
per rev
since in normal four stroke cycle there is one once you need to
put in
the mixture.
2) I am looking forward with the idea like a small electronic
carb to
start with that will give me more control with AF than with
carb. So I
am planning to modify the carb for the same.
I am planning to keep the same configuration of the carb for
idle
burn. The FI will start the action the moment I will pull the
throttle
i.e FI instead of main jet. Injector firing will be controlled
with
the resistance value of the throttle and may be other inputs.
I would appreciate if you can pour down your opinion on this.
Regards
>From John Smith 17 Jan 06
The MAP sensor would actually be easier for me since I can hook
it up and
measure the output while running it through the pressure range.
The tough
part is finding a positive pressure MAP without having to buy
anything. The
MAF is tougher because I need a flowbench to test it, but can
probably do
some extrapolation to rough out the CFM vs MAF
voltage/resistance. Its a MAF
from an '89-90 240SX.
<Date: Mon, 16 Jan 2006 16:30:05 EST
<From: ScottyGrover at aol.com
<Subject: Re: [Diy_efi] RE: Diy_efi Digest, Vol 11, Issue 6
<Message-ID: <140.537a6a28.30fd6a5d at aol.com>
<You might try hooking the output of your MAP sensor to the
Control input of
<the 555 (use your pot to check this input out, its output in
terms of time
<delay is roughly logarithmic for a linear input.) Hold your V
input at
line
<voltage (assumed 12VDC.) If your MAP is antilog, you should
have it made.
By
<the way, what type of MAP are you using; I am using an old
Datsun Z280 MAF.
Less
<calculation required.
<Scotty
>From Scotty Grover 17 Jan 06
That sounds like a winner. I have schematics for a system I am
in the
process of breadboarding--where would I fax these to in case
anybody is
interested. Not controlled by a 555 but employs one for
correction of non-linear sensor.
Scotty
>From Geoff Harrison 17 Jan 06.
Hi all, sorry if I left anyone of the list below. If you want
the rough drawing before I clean it up,
just ask.
I have just had a further idea, WBo2 would be ideal in this
approach.
Geoff
----- Original Message -----
From: "Geoff Harrison" <geoff_h at smartchat.net.au>
To: "S. K Rahman" <skrahman at gmail.com>; "John Smith"
<dirtrider218 at hotmail.com>; "Andrew Hopton" <hoptona at gmail.com>;
<scottygrover at aol.com>
Sent: Tuesday, January 17, 2006 9:36 PM
Subject: 555 timer controlled EFI
> Hi all, I have found the missing drawing. Its a bit rough, I
> hadn't done it on the PC, that's why I couldn't find it.
> When I get time I will clean it up, then upload it.
>
> Cheers
> Geoff.
>From Andrew Hopton 17 Jan 06
Geoff Harrison wrote:
> This subject has developed a bit of interest "off list" I
> suggest all
> further questions be sent via the list.
> There may be others out there interested. Most importantly,
> there are
> others out there with much more experience than I, to answer
> questions.
>
> I wonder if Steve could organise an area on the list site to
> store
> drawings and ideas. Any one else wanting the drawings or
> discussions
> already taken place can email me direct, and I will forward
> on.
>
> Geoff Harrison _______________________________________________
> Diy_efi mailing list
> Diy_efi at diy-efi.org
> http://lists.diy-efi.org/mailman/listinfo/diy_efi
>
Hear, Hear.
Geoff - is it feasible for you to post the text (or gist) of any
off-list discussion to the list?
Rgds, Andrew H.
>From Bill Washington 19 Jan 06
Geoff,
I would also be interested in seeing your block diagrams if you
could please
email them to me at this address.
I currently have an analog fuel injection system fitted (LE2
Jetronic) to my
Peugeot 505.
Best Regards
Bill
More information about the Diy_efi
mailing list