I have the cable setup that one way is gasoline the other way is wood gas If i run gasoline on wood gas timing i get rod pinging from pre detonation. I have one setting for woodgas timing that I use no mater rpms or load. I think it would be possible to get more power if the timing were to be adjusted according to rpms and load but that is near impossible to do manually.
2 Likes
with the new computer controls you can adjust timing fuel ratios number if sparks per firing even adjust throttle positions by codes if you could make a program that you could put in the pcm you could run a motor car truck just as good as with gas. but i am afraid it is beyond me at this time as well i was reading a artical in the carburator wood gas section about some one that put together a unit. i have a van that does not have a throttle it is contoled by the computer. it doesnt even have a distributer it has sensers on the crank that tell the computer what to do and it makes the decesions for meā¦ it ajust the timing, gas ratio, throttle, power needed and speed plus transmision shift ratios all electronicly maybe that is the way to go for whatever type of fuel.
2 Likes
Isnāt that a little scary to you? It is to me.
By the way, itās called control by wire.
Rindert
1 Like
Not really, because pretty much all EFI systems are fly by wire. Its not your foot dumping the fuel in. All you are doing is opening air flow and changing the position of the TPS. The TPS then tells the PCM / ECM hey were open this much (x) The ECM / PCM is then reading how much (air volume, temperature, Oxygen Sensor Reading, manifold absolute pressure, cam / crank shaft position etc. It then adjust fuel injector pulse and on most modern systems line pressure.
So the only real difference between fly by wire and pulling a cable with your foot is just that. I have never worked on a full fly by wire system, but I would have to assume there are fail safes were there are probably multiple sensors one on the go peddle and then at the intake throttle plate. If they dont jive then fuel is cut off. My assumption anyways.
3 Likes
To change timing on EFI you can use different MAP sensors to change the complete timing curve.
2 Likes
Hi larry i used potasium hydrocide.pure cristals draino. The cell is large in size though the clearances are not all too well. I mean i cut the 304 ss 16 gauge with my table saw 14" chop stone wheel.So the plates did warp in places of harder ss it would heat up more when cutting, so i tried too put all the buble warp in same direction, So even so i got 36 lpm with 8000 watt in the trial test cell.Its a lot of fidleing around now i need too take all apart and clean/ Ect/check all the gasgets, snug back up too reuse as torch.
1 Like
ha kevin so you are going to use it as a torch again that will be nice i have a plazma torch for cutting as well as a propane oxygen torch and three welders 2 stick 1 migi tried a electoligist unit once years ago didnt work well for me i didnt make it right thought of making another one .It is on the burner for now maybe one of these days
1 Like
hi rindert and matt ya i dont like fly by wire either but i think all cars will go that way . any that i know of has all ready i have 3 vans all that way if there is a problem the computer shuts the car down. But maybe that would solve the fuel problems with different fuels just put in a code and the car could sense the fuel type change the timing fuel mix even control the mixture of gas air for wood gas automaticly it would be like driving a normal car on what ever fuel you use even turn gasiline back on to wash the valves at shut down. and allow gas for startup then switch to wood gas ,propane etc.
1 Like
one thing about multi fuel injectors on a gas engine is they are not inside of the air intake I mean they are on the side not sticking in the middle so if there is tiny amounts of tar or dirt it will go right by them. so if you could control the gas air mixture right you could cut of the gas in the injectors and switch back and forth. it just needs a code to tell it what to do. There is a unit they were working on in the carb section of the forum. we have the ideas just need to put everything together. if we could you guys could drive on wood the your meets. and if you ran out of wood just tell the motor to change back to gas never even stop and no one would even know except once in a while you may get a puff out of the in feed gate. hha ha ha. Just thinking out side the boxā¦
1 Like
Ive pretty much already achieved electronic fuel mixing and have now integrated engine starting into the start up process. For gas full mixing, you could simply control the fuel pump pressure when switching between fuels. This way you can simply meter up or down the fuel pressure while letting the electronic controller automatically adjust as the gasoline input becomes richer or leaner during transition. Easy enough to do, you can use PWM from the Ardiuno and over ride the ECM controls.
1 Like
AAA i see i am not the only one thinking out side the box. I have been thinking that way for a while but was thinking of getting a program to control the engine computer but as you say drop fuel pressure and let the motor do what is does any way HHHMMM.
would iit also adjust the timing as well . Do you inject the wood gas into the intake tube or run it through the carberator
1 Like
Im not sure but I think on an EFI system some timing advance will already be automatic as the wood gasifier system is already loading the engine with vacuum.
On the small engines I mix the air / fuel remotely from the engine and feed directly into the carburetor. The vibration of the motor verses the added mass of the mixer installed directly to the carburetor will eventually break the bolts. I keep the gasoline system intact for trouble shooting or emergency cleaning if tar is suspected.
1 Like
I did a tutorial on this a few years ago. You can see this here. Wide Band Electronic Mixer Control Tutorial
Scroll to the end for the latest code revision.
2 Likes
with a car computer system the timing is set by the computer then when the fuel changes the engine knocks the knocks tell the computer to retard timing or advance timing by what information it gets but i dont know how much retarding the computer can give i know timing is set with the sensers on the crank. it will do what it can to stop knock and give best fuel burn as kevin said yesterday he retarded his timing 45 degrees . The computer might have a hard time figuring that out. I like the idea of keeping the carb. on the motor. to bad you coulnt get a fuel injector to put out the right fuel ratio then it would be out of the way and let the air gas or air fuel go the the motor with out bothering each other as the injector would be in the wall with just the tip in the air stream.if the system is set up to adjust the gas going in the injector should be as easy to make but for a car engine the fuel flow would be adjusted automaticly it should shut of when the fuel mix was right. the wood gas would be controled by a ball valve or a butterfly valve. and the tube be put in the intake manifold any where after the air flow senser the air flow senser would tell the gas flow valve how much to open for the given amount of air. if you didnt have the right amount of bio gas coming in the injectors should keep some fuel coming to make the difference sorry just the rambling of my thought patterns also as you said the gas could turn on a couple of minutes before shut down to prevent tar ont the valves.
1 Like
No thats not how it works. The MAP sensor controls the full timing curve of the engine. The Knock will also change timing but is more a back up to the MAP and will throw a code. The MAP sensor is the computer equivalent of your vacuum advance system on modern HEI distributors.
ya i figured that after i sent the message i dont know what i was thinking if this is the case then it gets more complicated need to think some more.
1 Like
Yup, They use "knockā sensor data to advance or retard the ignition timing. This allows engines to take advantage of higher octane fuel when they get it. A knock sensor is just a specialized accelerometer that looks at the shape of the vibration that corresponds to combustion events. Sharp peak ==> retard timing. Personally I donāt have a problem with a electronics, computers and all that, but a lot of people do, and fewer and fewer of us really understand our cars anymore. I think itās a shame. But I DO have a problem with stepper actuated throttles. I want instantaneous control of that little metal disc. Same reason I donāt like power steering or power brakes. Call me a stick āin the mudā, whatever.
1 Like
i have been using the fly by wire system for a while and the response is faster than manually all so the knock senser does retard timing but the map senser all so does. I was thinking that the knock senser detects the different octanes in the fuel so the oxygen senser would be able to tell the different fuels. but maybe not i will have to check further to be sure or not. if it did it would sure make things easier to figure out. I had a hard time with power steering i use to think any one with power steering was not a man . But i now love it. power steering abs brakes. I have been saved a few times and I mean saved a women pulled out in front of me slammed on her brakes i would have run the car over at the front door post abs allowed me to drive around her. still abs is not much good on slippery ice. the wheels go thump thump thump as they lock and unlock.
2 Likes
The knock sensor is the back up to the MAP. The primary function of the MAP sensor is to map the timing curve. Basically mimicking the vacuum advance of the old systems. The knock sensor comes in later and works with this mapping. If the ECM detects knock via this sensor and it logs too many times it will fault out and move to open loop mode. The engine knock sensors primary function is to tell the ECM if the engine running properly or not.
When the engine is loaded the manifold pressure will change and the MAP sends out a voltage range to the ECM to determine how much to advance the timing. Knock sensor detection will never advance timing, thats really its sole purpose as Pre detination will destroy the engine. Its job is to detect pre detonation. If the ECM detects knock it will retard timing and also change the injector pulse. A bad knock sensor can shut down the entire fuel system along with ignition control module.
The MSD control kits for carburetor conversions on the LS based GM engines only use a MAP for timing. It does not even use a knock sensor and this controller has very fine tuning capability for timing curves. This is the systems I used on the LS based machines that went to Italy
1 Like