small lockwood - propane injection problems?

[mk]

Ich spreche nur ein bischen mein freund!

Better a "bisschen" than "nichts", "richtig"?
...it's surprising me, anyway.

[Mike Everman]

Nicht war, Herr Commissar!

[Bruno Ogorelec]

I love German. Words you can really sink your teeth in. I still remember that technological hit of BMW's in the 1970s, the dreikugelbrennwirkungskammer. It was a special form of combustion chamber that generated strong swirl and gave very efficient combustion.

Some of their play on words is great but utterly untranslatable. I remember a very old advertising slogan of a Dortmund-based brewery -- funny and spirited but only really worked in German: "Was Krupp in Essen, das Sind Wir in Trinken!" I loved that.

[Mike Everman]

I like the Deutschlish warning sign, somethink like "Bitte kein gefingerpoken in der springenwerken, machen spitzensparken" something like that...

I also liked the VW spoof party t-shirt "Farfrompukin"

[evildrome]

Ich au' a bisl (aber nuer Bayerisch).

Wilson.

[Bruno Ogorelec]

Ich au' a bisl (aber nuer Bayerisch). Wilson.

I hope I will not offend anyone with an ethnic joke. I read it in a travel book on Central Europe by a British writer. It is a definition of Bavarians. They are the result of a failed attempt by the Almighty to make Prussians out of Austrians.

I wonder what it sounds like to Americans. In Central Europe, it is _very_ funny. Those people are our neighbors, more or less.

[mk]

I don't take your jokes too hard...
...anyway.


I got a camera from a friend yesterday and took some pictures (one while the engine is running). He'll burn them on CD, so I think I can post them monday or tuesday!

Today I got my small engine finally running, after some revising of course. It has a cc diameter of 2.7inches (-> attachement). I built the vaporizer with the same dimensions as the vaporizer of the bigger engine, just a bit shorter of course. Though it has 2x7 holes plus one at the underside (0.098inches diameter).

First it didn't want to start with the spark plug ignition, so I just turned the propane main valve a bit and lit the outflowing propane at the intake. Then I tried to blew the flame into cc. I had to try with air source positions and delivered air speed very hard, but it was finally optimal blowing the flame into cc with low air speed, an air source position 45° to the "intake-opening/symmetrical-line" point of intersection and perhaps 5...6inches away from it. After that I switched air speed on fast, while moving the hot air gun to the intake mouth. Regulating the propaneflow was also necessary for keeping the right fuel/air-relation. First I often overleaned or underleaned the mixture, because the main valve was just opened 1/4 turn or so. Still delivering air into the engine, I tried to get the optimal mixture (engine indicats "a will" to run alone). That was the trickiest point, because taking away the air source lets the engine overlean very quickly! But by taking it away slowly in an angle of about 10° or so I finally succeeded! First with short runs of about one or two seconds, but with a higher engine temperature the engine kept running. It ran best with a tiny main valve turn (no flames out of exhaust or intake!). I was able to throttle the engine till a 1/3...1/2 main valve turn, then the engine began to run unregulary and just stopped suddenly. When running in "optimal mode" it gets a good temperature/glowing distribution; cc and (especially) tail pipe at about 2...3inches, so it's the same as at my bigger engine. The flames in the cc are completely blue in this case.

I'm very glad that this engine ran, because it was calculated with my program (-> view topic in this forum part).

This engine is also advantegeous, because it doesn't consumpt so much fuel! Three days of testing my bigger engine and my 5kg propane bottle is nearly empty!

I'm looking forward trying something with liquid fuel injection, using a heating fuel burner of a home heating system...

[mk]

- Here are the promissed pictures. They aren't very good.

- Engine dimensions: NL=70mm NI=17mm NO=19mm CL=80mm CI=45mm CO=48mm TL=500mm TI=13mm TO=27mm

I got it nearly running on propane, with an air source delivering air into the engine for about 5sec. Then it stopped suddenly. Turning the main valve to the right place was a real headache! Perhaps using a needle valve in the propane injection line could bring some better results...
Firing it up like a jam jar (I used ethanol) I got something like that:"whoosh tip tip tip".
Can anybody tell me if this engine is too small for running alone, because I nearly think so?

[Tom]

i dont know about size, or i doubt i will be able to input any useful comments here, but the purple of the engine in the last picture is really quite eye catching. i have never seen anything like that before :o)

Tom

[vhautaka]

Hi, nice to see another success (especially after just the same kind of trouble I've had!)

I had the injector in the same way (in the beginning of the CC), except it was 6mm brake line and the holes were "drilled" with a saw. I think I should probably use a slightly bigger dia. tube made of something softer so I can drill it nicely.

But one question: What was the temperature during your successful runs?
I too have been suspecting the cold air has some ill effect even with properly pressurised/flowing propane.


Gotta burn more fuel until the greenhouse effect does away with these damn winters...

On the other hand, a Stirling engine could really benefit from that cold. Hmm... I've been eyeing some old dead air compressors with pistons/cranks still moving smooth and thight. Would only need a balanced replacer of the right dimensions... and a jam jar to heat one end :)


- ville

[mk]

...the purple of the engine in the last picture is really quite eye catching.

It just looks purple on the picture, but has been glowing orange at the run. Maybe because of the flash light...

But one question: What was the temperature during your successful runs?

I had temperatures of about +5...+10°C these days.

...,except it was 6mm brake line and the holes were "drilled" with a saw.

All of the holes together shouldn't be too small in the whole open area. The complete open area of them all in my engine is about 1.5 times bigger than the area of the 1/4inch / 7mm (inner dia.) connector pipe open area, because propane shouldn't move too fast aut of the vaporizer holes, else mixing won't be as good as you want it. I think "drilling" with a saw shouldn't have too big negative results if the holes aren't "really huge" ones then. The outflow angle of the propane is important, with about 90° to the symmetrical line, and the single hole dia., too, because of the vaporization effect. Using a generally larger vaporizer dia. (than yours at the moment) could be advanegous, too.

[mk]

I'm building a 150mm cc dia. engine now.
Can somebody tell me how much thrust it might be able to deliver?


I've build a tiny Lockwood engine as well (50mm cc dia.). First it didn't want to start, so I just put a needle valve in the fuel line. After doing this I got a nearly running engine. By keeping air forced through the engine and regulating the propane flow I got a kind of pulsating combustion. And suddenly the engine wanted to start, but with the first "bang" it killed the flame completely. There appeared just the same after relighting the propane.
I think the engine is too small for running alone, because with a needle valve the propane flow can be adjusted very well. But the valve restricts the fuel flow to much, so the requiered amount of fuel isn't in the cc at the beginning of the next cycle. This problem increases extremly at tiny engines with their high resonace frequencies, because in you'll have to decide whether should be to delivered the right amount of fuel OR the right mixture of fuel and air. But BOTH is needed...maybe lenghtening the tailpipe could help, but this produces other problems...hmmm...
So, has anybody an idea for improving s.th.?

[Mike Everman]

the quick answer on thrust is about 2 lb per square inch of exhaust pipe area or so. the "or so" apparently should be capitalized!

[mk]

It was very cold today (~0°C), so I was just able to get one single run of one of my engines, damn. The problem: I planned making some pictures and a few videos today with a friend.
I'll post more when it's getting warmer. I plan driving somewhere, so nobody could become angry about the noise...

The pictures of today (I can send more videos and pictures if somebody wants to):

[mk]

more pictures