Gentlemen,
All of these engines have fixed intake valve opening and closing timing.
And that timing was set up for gasoline and the overall power curve the designers desired on gasoline.
Search up and read the problems the designers are having with pure hydrogen fueled internal combustion piston engines.
Intake back firing from hydrogen sneaking back past the not quite closed intake valve under certain conditions. AND THIS after converting to direct hydrogen into the combustion chamber to avoid any hydrogen in the intake.
The "certain conditions’? After a deacceleration event creating a strong intake vacuum . . . THEN followed up by a sudden engine demanded power creating high in-cylinder pressure.
And that squeeze’s out some in-cylinder hydrogen back into the intake.
Of course sucked woodgas we supply the hydrogen into the intake. Sudden in-cylinder pressure is pushing hot combustion gasses back into the intake.
Close the intake valve a bit earlier would be the solution.
Watch. The manufactures releasing hydrogen IC engine will be using phaser shifting camshafts.
S.U.
As J.O., MichealG’s and Wayne’s experiences shows why do anything if your particular engine combination does not have a problem??
If just operator changing can solve the problem.
The true charcoal guys NOT having the problem says much, eh on just what is causing the problem.
Great to hear on your clean intake J.O.
You got the magic combination now too, eh.
S.U.
Facts in which a return fire occurs in the intake manifold:
low engine speed
sudden opening of the throttle
a similar thing happens with LPG (propane) engines
How do I solve this ?:
spark plugs mandatory for gas (NKG LPG1 are best) because ignition of gas under high pressure requires a lot of concentrated energy, especially if the mixing ratio is poor, the mixture does not ignite, and the rest of the mixture ignites after the exhaust stroke, when the spark jumps again this time however, the mixture ignites because it is under low pressure, and a moment later the suction valve opens and the combustible mixture ignites the mixture in the intake manifold.
leaking suction valves on which dirt accumulates, or dry sealing, helps to dose the oil to lubricate the valve seats
installation of anti-knock flaps in the suction pipe to prevent damage, my gas mixer also does this
Engines with a lower compression ratio usually do not have these problems, and engines with a compression ratio of 1:10 or more have these problems, but they develop much more power, Jo was convinced of this, and Joni certainly encountered this problem on his own Opel Astri, where he increased compression
I hope the translation is understandable
Wow, I turn my back for 12 hours and there are a dussin replies on my thread @Tone Very good info. Thank you. @SteveUnruh Excellent explanation on valve timing. @Handy_Andy The Volvo is a free spinner. I’m almost tempted to try your “one tooth on the belt” trick
After reading @KristijanL and others about lean mixture, air leaks and such last night, I started plugging every connection on the intake manifold this morning. Saving only the brake vacuum hose Cranked up and it emediately ran rich. A tiny hose for a thingy, mounted on the firewall, had to be reinstalled. My guess it’s a vacuum sensor for “don’t care about enviroment and oxygen-sensor WOT enrichment” or something like that.
After that it was time for lightup. I remembered @don_mannes wanted such a video. All hyped about how all my plugging would work out and the camera rolling, I messed up a few steps. Notice at the end, I remarked it takes longer than usual to be able to kill the fuel switch. No wonder - I forget to open my woodgas valve, but manage to maintain an idle
Back home after 20 miles, 5 pops, bent butterflies (again) and in a bad mood, I decided it was time to replace those soft, mild steel, no good roof tin plates.
I cut stiff ss disks, and as I was mounting them my father showed up for a visit. I took him for his first ride in the Volvo. Another 10 miles, occational 65-70 mph on winding 45 mph roads. Only remarks was “fuel is free, but taking corners in that speed will wear tires out”
No pops. Coincidence?
Sounds like its going your way now JO! Good performance even with an observer, better write that in your diary.
Now if anybody wants to go down the rabbit hole, i remeber a setup in one of my engineering books where the relative timing of two shafts could be adjusted on the fly with a pair of idler sprockets. Moving the idlers position would change the relative position of the two shafts.
Thank you all for a warm welcome back. I just finished up reading about the Volvo and the Sko—(can’t remember how to spell- haven’t learned how to pronounce it even). Anyways it took me a good part of 2 days of reading time. And now if I was thinking of a new build it would take much re-reading to digest. It is because reading takes so much time my mind has given up getting enthused about work in the shop. I , hopefully will be able to sneak back in from tome to time
JO, I see you are using ‘‘paper’’ bags. Do you have an in with someone in the ‘‘paper’’ business? Everything here is plastic-- even the feed bags I was buying from the feed mill and they rot in the sun.
Keep building guys, I may get interested in a new build if Biden keeps gas prices going up and inflation is hitting the stores–gas is $3.19 today.
TomC
Wow that some cheap fuel Tom. I have see regular as high as $3.85 and the low is at $3.75 and it still going up every week here. But I do have vehicle that I can ride in a SWEM as I pass by.
Bob
If I loaded up my 275 gallon tanks and drove to your side to fill them I would end up loosing money at the milage the v10 gets! Paid 4.19 today to fill the bike
Friends, regarding the pops in the collector, I can say the following; I came across them only once, when I rolled my Opel through the puddles with a very high quality. At the same time, water got into the distributor and I received a discharge on all four candles, the situation was quickly resolved by wiping all parts with a dry rag. My engine has an ignition distributor and it only sparks when needed, no second spark. I wanted to add a comment about the ignition timing in engines with a compression ratio of more than 1:10, with an increase in the compression ratio, there is no need to increase the advance angle at all, the mixture starts to burn much sharper and knock sensors begin to respond to this fact, which leads to normal operation of the standard ignition systems.
Joni, what is the compression ratio of your Opel? I increased it to 1:13 in my Subaru and I can say that the torque increased significantly and the consumption decreased. Joni, when you say that the pre-ignition angle does not need to be increased, I agree with you, because at high pressure and condensed mixture we achieve combustion in an instant, but if the ignition happens too early, when the piston moves up and further compresses the burned mixture, detonation occurs. which, in addition to leaking suction valve seats, can cause backfire,
Wow! 1:13 is a lot, is this a real ratio or is it just your compression ratio (pressure in the combustion chamber with a pressure gauge instead of a spark plug)?
I have a compression ratio of 1:11 in the engine (calculated mathematically) and the angle of the ignition distributor corresponds to the factory mark.
subaru has an interesting engine construction, ej18, ej20 and even ej25 have the same geometry, so the cylinder heads can be easily installed between the mentioned types. So I installed the ej18 engine heads on the ej20 and replaced the original 1.6 mm thick gasket with a 0.6 mm gasket so the mathematical compression ratio is somewhere around 1:13. in the original it has 1:10
