Hit and Miss Engine
Hit and Miss Engine
(OP)
Hi everyone,
I wish to convert a 4 stroke engine into a hit and miss engine - or something similar.
I have made a flux generator that is powered by the small (Carburetor) 4 stroke using a flywheel. I wish now to make the engine more fuel efficient.
My plan is to use an Arduino and solenoid to shut the fuel and spark on & off so it fires once every 2-3 seconds.
I am a bit green with 4 stroke engines and would love to hear any suggestions.
Thank you
I wish to convert a 4 stroke engine into a hit and miss engine - or something similar.
I have made a flux generator that is powered by the small (Carburetor) 4 stroke using a flywheel. I wish now to make the engine more fuel efficient.
My plan is to use an Arduino and solenoid to shut the fuel and spark on & off so it fires once every 2-3 seconds.
I am a bit green with 4 stroke engines and would love to hear any suggestions.
Thank you





RE: Hit and Miss Engine
What is this thing powering?
Remember - More details = better answers
Also: If you get a response it's polite to respond to it.
RE: Hit and Miss Engine
It is a capital mistake to theorise before one has data. Insensibly one begins to twist facts to suit theories, instead of theories to suit facts. (Sherlock Holmes - A Scandal in Bohemia.)
RE: Hit and Miss Engine
RE: Hit and Miss Engine
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The Help for this program was created in Windows Help format, which depends on a feature that isn't included in this version of Windows.
RE: Hit and Miss Engine
B.E.
You are judged not by what you know, but by what you can do.
RE: Hit and Miss Engine
see 'how hit-and-miss-engines work' in https://en.wikipedia.org/wiki/Hit-and-miss_engine
Fifty plus years ago, I saw 'Rumely Oil Pull' engines running at Henry Ford Museum. I think they worked by exploding kerosene and air in a large external combustion chamber, and expanding the hot gas through what was mechanically a steam engine. The sound was essentially the same as that produced by a regular h+m engine.
Mike Halloran
Pembroke Pines, FL, USA
RE: Hit and Miss Engine
It is a capital mistake to theorise before one has data. Insensibly one begins to twist facts to suit theories, instead of theories to suit facts. (Sherlock Holmes - A Scandal in Bohemia.)
RE: Hit and Miss Engine
"Schiefgehen wird, was schiefgehen kann" - das Murphygesetz
RE: Hit and Miss Engine
Cheers
Greg Locock
New here? Try reading these, they might help FAQ731-376: Eng-Tips.com Forum Policies http://eng-tips.com/market.cfm?
RE: Hit and Miss Engine
It was salvaged after a fishing boat that is was the motive power for sank, in the harbor. Seems the starting bar got jammed in the starter bar hole in the flywheel on starting. The bar went around with the flywheel and plowed a huge smile in the lowest point of the hull. The boat sank fast.
Keith Cress
kcress - http://www.flaminsystems.com
RE: Hit and Miss Engine
Also systems like this actually lightly coat the inlet chamber in a thin film of petrol. If you manage to cut off the fuel, this film dries out, but then on re-start the engine coughs a lot. I remember on a car some time ago where they used carbs and tried to cut off fuel on the overrun, they found when you put your foot on the accelerator it wouldn't go properly so had to actually cycle the fuel on and off when on overrun.
Fuel injection now, especially electronic FI, is a different thing.
All up no one can work out why you're trying to make your engine less efficient than it is at present....
Remember - More details = better answers
Also: If you get a response it's polite to respond to it.
RE: Hit and Miss Engine
What is that carb ? It looks a bit like a Stromberg.
B.E.
You are judged not by what you know, but by what you can do.
RE: Hit and Miss Engine
RE: Hit and Miss Engine
Remember - More details = better answers
Also: If you get a response it's polite to respond to it.
RE: Hit and Miss Engine
"Schiefgehen wird, was schiefgehen kann" - das Murphygesetz
RE: Hit and Miss Engine
RE: Hit and Miss Engine
There are after market kits that add fuel injection to small gasoline engines. You can then simply cycle the injection off and on.
The big question is "WHY?"
Most small engines have a serviceable governor.
If your engine does not have a governor, you can probably make one with a flapper that the cooling air blows against. The faster the engine the more force on the flap. Use a spring to hold the throttle open. Use linkage from the flap to close the throttle at the speed that you want.
It will take some cut-and-try and trial-and-error to get it right but there have been many small engines governed in this fashion.
Bill
--------------------
"Why not the best?"
Jimmy Carter
RE: Hit and Miss Engine
Keith Cress
kcress - http://www.flaminsystems.com
RE: Hit and Miss Engine
je suis charlie
RE: Hit and Miss Engine
The old school hit and miss engines worked by cracking open the exhaust valve and the intake valve was purely suction operated, so it did in fact successfully shut off all fuel (and air) ... although the nature of operating an intake valve in this manner severely limits the RPM and operating pressure (compression ratio) of the engine.
The various late model engines that use "cylinder de-activation" leave the intake and exhaust valves shut, which obviously shuts off supply of all air and fuel.
Shutting off a direct-injection injector will shut off all the fuel.
Shutting off a port injector won't because the inside wall of the intake port is wetted with fuel during normal operation, and if you leave the intake valve working, that's going to gradually get drawn in over the following (skipped) cycles. The air/fuel mixture will be too lean to fire, but the fuel is still going through the engine being wasted.
Carburetor, same problem but even worse.
Any emissions-regulated strategy that involves shutting off the fuel but not the air will screw up the operation of a 3-way catalyst. The cylinder-shutoff mechanisms that completely shut off valves don't have an issue. "Deceleration fuel cut" on a normal port-injected engine isn't a problem because whatever bit of fuel that was wetting the port walls goes through the engine and gets oxidized by the catalyst and it only happens the moment you take your foot off the accelerator - not continuously the whole time the engine is running (in hit-and-miss mode).
The original poster has not showed up in this thread to explain WHY he wants to do this doomed experiment.
RE: Hit and Miss Engine
John R. Baker, P.E. (ret)
EX-Product 'Evangelist'
Irvine, CA
Siemens PLM:
UG/NX Museum:
The secret of life is not finding someone to live with
It's finding someone you can't live without
RE: Hit and Miss Engine
The reason I am doing this project is because I have successfully built a small electro/magnetic generator (100W). Naturally my next step was to have a quite, efficient engine to run it. I actually have a brand new Honda GX35 Motor available (1kW which means its 10% efficient = poor). I am also an admirer of the old Hit and Miss engines of the past. So that is how I came up with this concept. Bringing new and old technology together. I'm not sure if this is even conceivable but was hoping to get some insightful feedback.
Wayne
RE: Hit and Miss Engine
Try something like this https://www.stevewebb.co.uk/index.php?pid=LE41F&am...
Engines running continuously work much better than one starting and stopping.
Remember - More details = better answers
Also: If you get a response it's polite to respond to it.
RE: Hit and Miss Engine
and I will grant that the real efficiency is probably pretty lousy because the engine will be running at such a small fraction of its rated load, but it's not determined by 100 W / 1 kW ... if the generator only draws 100 W from the engine then the engine will simply run at 100 W output - part load - not full fuel delivery. You don't have (or haven't provided) sufficient data to establish what the efficiency of this powertrain will be.
Running the engine in hit-and-miss mode won't make it better, though!