I am including pictures of my engine, not photo's (my digital camera is on the fritz) but pictures I got from the web. Also included is a BHP and torque graph just so that you can see the engine specs.
Your idea to check an existing engine (that works) is a very good one, so we can reverse engineer the necesary signals, voltages, maps, etc. Or just get the feel of the whole setup.
I am still trying to get a home made air mass sensor up and running. I wanted to use nicrome wire, but apparently it is as scarse as chickens with teeth, but, I read somewhere that you can use the bulb of an incandecent bulb as one, just run less volt and current through. Should work very nicely.......
Wynand.
▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔ Why didn't I think of THAT!!!!
Wynand,
You can use a MAF sensor but they are not needed my TBI truck does not have one it just uses a MAP sensor and a oxygen sensor. But the homemade MAF might work but might not be real reliable..just try it and see.
why not just crack open an old toaster or hair dryer for it's heating element? They use something equivalent to a nicrome wire and the wire diameter is much bigger than that of any normal light bulb I've seen.
Wynand,
I think I am going to use the SX 48 proto board for this project and put it to the test on my old Chevy Truck. The truck is just an old one I have and have no use for so it will be cheaper to use it than to buy all the parts to make a small motor run and I can always put back in the old ECU and go...I will try to get some pics of the truck and I have some electrical prints on it I will get alot of info off..
I am very interested in your Chevy truck, even though no BS2, still would like to see how you do it. I will carry on with the BS2 and my honda, try to hit my head oftern enough, maybe it'll work !!!!!!!! (lol)!!!!!!
▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔ Why didn't I think of THAT!!!!
Yeah I think It will work on your honda, the BS2 just does not have the power needed and the SX48 has hardware timers that make a great PWM signal..I will post more soon.
http://www.megasquirt.info/· check them out,· they have lots of info about· building your own fuel injection.· i acutaly just built one, using the sx/28 chip,· runs real good too.· heres the basic overview of how it works.
i used the MPX4250A for the map sensor,· about 15 from digikey,· it runs from 2.9 to about 35 psi,· abusote
for driving the injectors and the ignition i used MIC4421,· its a 9 amp peek FET driver,·
for the throttle posistion sensor just used a linear pot.
got a cheep o2 sensor and some cheep temperature sensors.
used 2 a/d chips PCF8591 run set is running 5 volts, the other is 2.5 volts, for the o2 sensor and temp sensors
and i used the hall effect sensor they sell at this site.
basicly have the hall sensor hooked up to the crank and set up the program so that it runs every second pulse,· ie for the 4 stroke, 2 revolutions per firing event.
then it reads all the sensors and then calcuatles the pulse width.
the equation is pretty simple
[noparse][[/noparse]MAP(KPA) X 1000] / [noparse][[/noparse] .28650 X TEMP(C)] = air density from map sensor and temperature sensors
then take your engine displacement (cc)
air density X [noparse][[/noparse]displacement / 2] X [noparse][[/noparse]1/14.7(fuel/air ratio)] X [noparse][[/noparse]injector flow rate] = pulse width.· now thier are going to be constence you have to add in depending on what units you use.·
so thats your base pulsewidth,· now the engin isnt 100 % efficent at sucking all the air from the manifold into the cyledners.· its around 70%· so you multiply that in to the equation· and for the o2 sensor.· .45volts is perfect. less then that is lean and more is rich.· basicly setup a if then statment to add or subtract from the air fuel ratio.
that will get it running pretty good but it can be better,· used the tps input to make the mixture richer when it changes postion quickly,· like an accelorator pump.· and you can also add in stuff so that it will run the ignition too.
one pic is the engine in the design stage,· just finished today building the acutal ECU, next picture
hope this info helped out,· need anymore info just ask
markistuff,
I know about megasquirt well they have a nice ECU, I have decieded on the SX48 because it has the internal Timer that make a great PWM output. My Chevy pickup has all the sensors I need on it already because it is a TBI injected motor already. The thing I am looking into is the Distribitor I think i has a hall sensor in it already and I can tap off that for my RPM readings. As far as the timming control I have been looking into how to control that with the HEI distribitor I have do you know how they control the timming advance?
depends if its electronicly controlled or mechanicly.· the mechanical one uses a hybrd system,·centrifial and vacuum advance working together,· im not sure how the electronicly controlled one works.
Hey all, good work so far! by now you should be hitting some perverbial brick walls, I think i'll join the circle here and be the first (i think) to attempt this on the propeller - my head could use a WHOLE LOTA LUMPS.. EEEE!! (pete puma impersonation) lol.
As for the fuel pressure vs pulsewidth, i wouldn't recomend cutting fuel psi, norboosting it too much as injectors were designed to be very efficient at atomization within a certain psi range. Both of you should be fine with just adjusting the Pulse width, additionally, smooting out the throttle response curve and "drivability-smoothness" (response accuracy under load) could greatly benefit from a wide-band O2 sensor giving you alot more precision than the cheapy which is a narrow band, ...very narrow band.
My first BS2/SX Video card project was going to be an electronic crossover/light sequencer for car audio (complex signal/light control via a Graphical User Interface) the BS2's job here only had to run the GUI via the SX video module,read data from the touchscreen hardware (look in mouser.com), and send simple SPI commands to digital pots. - Never made it past the GUI! That may be my next project with the Propeller.
I have to agree with Mike Green near the begining of this thread, the prop is AMAZINGLY fast, easy to use, and POWERFUL!!!!
Please view my thread in the propeller forum on this project, or subscribe to it if you like. I formerly would like to invite you all to my thread and i'm almost expecting some critisizm on my efforts, I'm hoping all your suggestions will inevitably lead to improvements as a set of fresh eyes will always have a different point of view.
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Definetly a E3 (Electronics Engineer Extrodinare!)
"I laugh in the face of imposible,... not because i know it all, ... but because I don't know well enough!"
I found this site while looking for ideas for my new project (information display/storage device) and thought of some information that may help you all.
I'm not very knowledgeable on electronics (I just ordered my first BS2 experimenter kit) but I am fairly good at cars (ASE Master Technician). The timing on he fuel delivery is not very important at all. Many cars run non-sequential port fuel injection. Meaning all the injectors receive the same signal. Also, the valve is open for a very short time during the total cycle. When the valve is closed the fuel just 'sits' in the port. Not a big deal, especially once the engine is warm, because it will just evaporate off the port walls and valve.
As for your monitoring and fuel calculations I would recommend something like.....
Use a lookup table based on MAP and RPM. MAF is a very poor way to measure incoming air, especially on engines with large variations in intake pressure (ie: 1/2 cylinder, 2 stroke, or high horsepower engines). The MAP may need some type of smoothing circuit. I like the simplicity of a 'vacuum chamber' type design for it's simplicity. Just a small chamber that the sensor reads from, that is connected to the intake manifold by a vacuum hose.
For fuel economy, use two sets of lookup tables based on the TPS, switching around 70%.
IAT could be applied as a correction factor to the pulse width.
Engine temperature can be used for cold start enrichment (as a correction) but will not be have any effect during use on watercooled engines (because engine temperature is held constant by the thermostat). I'm new to air cooled engines, so it may be needed there. Remember, that even though you normally want to lean the mixture as temperature increases, you really want it to enrich the mixture later to lower combustion temperature.
As for the O2 sensor, you are using narrow band sensors, which are not ideal for tuning. Older cars used the O2 sensor to apply a broad range correction factor, after the engine is warm (ignore O2 during cold start enrichment). The O2 sensor is ignored when above the high throttle point. Newer cars use wide band type O2 sensors and store the corrections into tables, some RPM only, some RPM and load. You may be able to even have the correction be applied directly to the original lookup table, making the system 'self-tuning'. The correction amount will need to be limited, to prevent overcorrection. Some of you may have seen the ricer-light machines (aka: air:fuel meters) bouncing back and forth. This is the ECM adjusting the air-fuel based off O2 readings.
Hello All, I don't know if you are familiar with the Jetronics or as I like to call it, the junktronics fuel system. It is a simple lever operated plunger that allows fuel to be mechanically metered to all cylinders at once. If the engine temps are too high or to low other, two other externally controlled actuators relieve the controlling tension by manipulating fuel pressures and affecting fuel flow. This is a very convoluted method of controlling fuel flow. As the throttle body is opened by the mechanical linkage, a plate sampling the air flow moves the lever that controls the plunger. I am sure a BS2 is capable of handling three to five inputs with no problem. Here is what I had in mind: 1. is ignition on true/false 2. is engine rotating true/false 3. is the engine temperature above x degrees true/false 4. what position is throttle body in (x amount of resistance) I have read so much info regarding this subject and I know the junktronics system does not take any of this into account, the lever either goes up or down. Am I under simplifying this project?
Comments
I am including pictures of my engine, not photo's (my digital camera is on the fritz) but pictures I got from the web. Also included is a BHP and torque graph just so that you can see the engine specs.
Your idea to check an existing engine (that works) is a very good one, so we can reverse engineer the necesary signals, voltages, maps, etc. Or just get the feel of the whole setup.
I am still trying to get a home made air mass sensor up and running. I wanted to use nicrome wire, but apparently it is as scarse as chickens with teeth, but, I read somewhere that you can use the bulb of an incandecent bulb as one, just run less volt and current through. Should work very nicely.......
Wynand.
▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔
Why didn't I think of THAT!!!!
You can use a MAF sensor but they are not needed my TBI truck does not have one it just uses a MAP sensor and a oxygen sensor. But the homemade MAF might work but might not be real reliable..just try it and see.
my 2 cents,
Marty
Now you see why my post always say "Why didn't I think of that!"
Thanks a bunch for the neat tipp!!!
▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔
Why didn't I think of THAT!!!!
I think I am going to use the SX 48 proto board for this project and put it to the test on my old Chevy Truck. The truck is just an old one I have and have no use for so it will be cheaper to use it than to buy all the parts to make a small motor run and I can always put back in the old ECU and go...I will try to get some pics of the truck and I have some electrical prints on it I will get alot of info off..
I am very interested in your Chevy truck, even though no BS2, still would like to see how you do it. I will carry on with the BS2 and my honda, try to hit my head oftern enough, maybe it'll work !!!!!!!! (lol)!!!!!!
▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔
Why didn't I think of THAT!!!!
i used the MPX4250A for the map sensor,· about 15 from digikey,· it runs from 2.9 to about 35 psi,· abusote
for driving the injectors and the ignition i used MIC4421,· its a 9 amp peek FET driver,·
for the throttle posistion sensor just used a linear pot.
got a cheep o2 sensor and some cheep temperature sensors.
used 2 a/d chips PCF8591 run set is running 5 volts, the other is 2.5 volts, for the o2 sensor and temp sensors
and i used the hall effect sensor they sell at this site.
basicly have the hall sensor hooked up to the crank and set up the program so that it runs every second pulse,· ie for the 4 stroke, 2 revolutions per firing event.
then it reads all the sensors and then calcuatles the pulse width.
the equation is pretty simple
[noparse][[/noparse]MAP(KPA) X 1000] / [noparse][[/noparse] .28650 X TEMP(C)] = air density from map sensor and temperature sensors
then take your engine displacement (cc)
air density X [noparse][[/noparse]displacement / 2] X [noparse][[/noparse]1/14.7(fuel/air ratio)] X [noparse][[/noparse]injector flow rate] = pulse width.· now thier are going to be constence you have to add in depending on what units you use.·
so thats your base pulsewidth,· now the engin isnt 100 % efficent at sucking all the air from the manifold into the cyledners.· its around 70%· so you multiply that in to the equation· and for the o2 sensor.· .45volts is perfect. less then that is lean and more is rich.· basicly setup a if then statment to add or subtract from the air fuel ratio.
that will get it running pretty good but it can be better,· used the tps input to make the mixture richer when it changes postion quickly,· like an accelorator pump.· and you can also add in stuff so that it will run the ignition too.
one pic is the engine in the design stage,· just finished today building the acutal ECU, next picture
hope this info helped out,· need anymore info just ask
I know about megasquirt well they have a nice ECU, I have decieded on the SX48 because it has the internal Timer that make a great PWM output. My Chevy pickup has all the sensors I need on it already because it is a TBI injected motor already. The thing I am looking into is the Distribitor I think i has a hall sensor in it already and I can tap off that for my RPM readings. As far as the timming control I have been looking into how to control that with the HEI distribitor I have do you know how they control the timming advance?
depends if its electronicly controlled or mechanicly.· the mechanical one uses a hybrd system,·centrifial and vacuum advance working together,· im not sure how the electronicly controlled one works.
I will crank it up on the original PCM and see what type of signal it gets to control it..
http://forums.parallax.com/forums/default.aspx?f=7&m=192262
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John J. Couture
San Diego Miramar College
You will love this video
As for the fuel pressure vs pulsewidth, i wouldn't recomend cutting fuel psi, norboosting it too much as injectors were designed to be very efficient at atomization within a certain psi range. Both of you should be fine with just adjusting the Pulse width, additionally, smooting out the throttle response curve and "drivability-smoothness" (response accuracy under load) could greatly benefit from a wide-band O2 sensor giving you alot more precision than the cheapy which is a narrow band, ...very narrow band.
My first BS2/SX Video card project was going to be an electronic crossover/light sequencer for car audio (complex signal/light control via a Graphical User Interface) the BS2's job here only had to run the GUI via the SX video module,read data from the touchscreen hardware (look in mouser.com), and send simple SPI commands to digital pots. - Never made it past the GUI! That may be my next project with the Propeller.
I have to agree with Mike Green near the begining of this thread, the prop is AMAZINGLY fast, easy to use, and POWERFUL!!!!
Please view my thread in the propeller forum on this project, or subscribe to it if you like. I formerly would like to invite you all to my thread and i'm almost expecting some critisizm on my efforts, I'm hoping all your suggestions will inevitably lead to improvements as a set of fresh eyes will always have a different point of view.
▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔
Definetly a E3 (Electronics Engineer Extrodinare!)
"I laugh in the face of imposible,... not because i know it all, ... but because I don't know well enough!"
For ignition control, I would recomend a GM HEI module. They are cheap and easy to use. Here is a page explaining their function:
http://72.14.205.104/search?q=cache:JqGGMoZP_e4J:www.megamanual.com/ms2/GM_7pinHEI.htm+gm+hei+ignition+control&hl=en&ct=clnk&cd=3&gl=us&client=firefox-a
original (if it works)
http://www.megamanual.com/ms2/GM_7pinHEI.htm
I'm not very knowledgeable on electronics (I just ordered my first BS2 experimenter kit) but I am fairly good at cars (ASE Master Technician). The timing on he fuel delivery is not very important at all. Many cars run non-sequential port fuel injection. Meaning all the injectors receive the same signal. Also, the valve is open for a very short time during the total cycle. When the valve is closed the fuel just 'sits' in the port. Not a big deal, especially once the engine is warm, because it will just evaporate off the port walls and valve.
As for your monitoring and fuel calculations I would recommend something like.....
Use a lookup table based on MAP and RPM. MAF is a very poor way to measure incoming air, especially on engines with large variations in intake pressure (ie: 1/2 cylinder, 2 stroke, or high horsepower engines). The MAP may need some type of smoothing circuit. I like the simplicity of a 'vacuum chamber' type design for it's simplicity. Just a small chamber that the sensor reads from, that is connected to the intake manifold by a vacuum hose.
For fuel economy, use two sets of lookup tables based on the TPS, switching around 70%.
IAT could be applied as a correction factor to the pulse width.
Engine temperature can be used for cold start enrichment (as a correction) but will not be have any effect during use on watercooled engines (because engine temperature is held constant by the thermostat). I'm new to air cooled engines, so it may be needed there. Remember, that even though you normally want to lean the mixture as temperature increases, you really want it to enrich the mixture later to lower combustion temperature.
As for the O2 sensor, you are using narrow band sensors, which are not ideal for tuning. Older cars used the O2 sensor to apply a broad range correction factor, after the engine is warm (ignore O2 during cold start enrichment). The O2 sensor is ignored when above the high throttle point. Newer cars use wide band type O2 sensors and store the corrections into tables, some RPM only, some RPM and load. You may be able to even have the correction be applied directly to the original lookup table, making the system 'self-tuning'. The correction amount will need to be limited, to prevent overcorrection. Some of you may have seen the ricer-light machines (aka: air:fuel meters) bouncing back and forth. This is the ECM adjusting the air-fuel based off O2 readings.
MCZ33812
www.freescale.com/webapp/sps/site/prod_summary.jsp?code=MC33812&fsrch=1
and reference design board
www.freescale.com/webapp/sps/site/prod_summary.jsp?code=KIT33812ECUEVME&parentCode=MC33812&fpsp=1&nodeId=01435979968460
-dan
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Arguing with myself--sometimes me, myself, and I don't always agree.
(Former) Caterpillar product support technician