Author Topic: Bruce Atmospheric gas engine  (Read 1027 times)

Offline Tonyr

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Re: Bruce Atmospheric gas engine
« Reply #15 on: August 27, 2018, 04:59:35 PM »
Hi Graham.

Thanks for the info.
I will try it with the flame ignition to start with.
If that gets too stressful I will look at the alternatives.

Tony

Offline Alyn Foundry

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Re: Bruce Atmospheric gas engine
« Reply #16 on: August 27, 2018, 05:52:07 PM »
You're welcome Tony.

It proved to me that I don't know everything about the " new " additions that have come from the same stable!

If you find a foolproof method of flame ignition please let us know, I'd be one of the first to implement it.

Cheers Graham.

Offline Tonyr

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Re: Bruce Atmospheric gas engine
« Reply #17 on: September 20, 2018, 07:13:30 PM »
Hello,

I have a question.
Has anybody ever seen this model of engine running on Propane, Butane
I have completed the build and tried to get it running.
I am using gas from a blow lamp canister, a Propane Butane mix.
I can get it to fire but not run.
I have moved the valve from the top of the cylinder, to the cylinder head as in the other engines on this thread.
This is an improvement, but not enough.
As Graham experienced the flame blows out.
I used a blow lamp directed at the ignition hole, this doesnít blow out.
If I turn the flywheel with my finger it fires every stroke.
There is not enough power to keep the engine going under its own power.
The engine is as free as it can be but is quite heavy.
Do these engines run on Propane Butane or am I wasting my time.
Thanks

Tony



Offline Jo

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Re: Bruce Atmospheric gas engine
« Reply #18 on: September 20, 2018, 08:00:09 PM »
Have your tried it with a glow plug?

These engines should be run on coal gas which has a wide ignition range. Propane/Butane are more fussy, a glow plug will let it ignite when it wants to.

I was going to fit two flywheels on my engine  ;)

Jo
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Offline Alyn Foundry

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Re: Bruce Atmospheric gas engine
« Reply #19 on: September 20, 2018, 08:09:08 PM »
Hello Tony.

I only ever used plain Propane to run mine with. We discovered that Butane wouldn't ignite on our hot tube models that we produced, but that's a different story.

I'm not sure about the mix of the two fuel gasses but heat is heat and with the correct fuel to air ratio you should have a rapid expansion occur.

I wonder if by moving your valve from the vertical to horizontal you might be impeding the exhaust part of the stroke? Having been told by Jo that this valve hangs and acts as both inlet and exhaust, is it being pushed shut after the expansion?

The only other factor that I can comment on is the fuel/air ratio. Both these gases have a high calorific value but are rather slow burners compared to the likes of Hydrogen etc. Are you able to finely adjust the flow? I'd suggest fixing your blowtorch and rotating the engine whilst slowly increasing the volume of gas to the inlet valve. You should arrive at a point where the engine starts really popping, that would be the optimum mixture.

Cheers Graham.

Offline Tonyr

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Re: Bruce Atmospheric gas engine
« Reply #20 on: September 20, 2018, 09:02:52 PM »
Jo
I havenít yet tried a glow plug.
The engine will fire reliably with the blow lamp at the ignition hole.
It doesnít have the power to spin the engine.
The engine has two flywheels, I tried it with one removed also.

Graham

I have considered that the exhaust isnít working properly.
At present there is no spring fitted to keep it open, that is the next test.
I think it is impeding the exhaust to an extent.
I have also varied the distance the valve opens.
It does open and close better in the horizontal than vertical.
I have set the gas flow exactly as you say and it does fire on every stroke reliably.
If I increase the pressure I need to spin it faster, I presume this is due to the time the gas valve is open.

I will fit the spring and maybe try Propane without the Butane.
I will let you know if it improves the runningí.

Thanks for the ideas

Tony

Offline Roger B

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Re: Bruce Atmospheric gas engine
« Reply #21 on: September 21, 2018, 07:52:46 PM »
Coal gas (town gas) had quite a high hydrogen content that was easy to ignite with a hot tube, propane and butane are harder to fire.
Best regards

Roger

Offline Tonyr

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Re: Bruce Atmospheric gas engine
« Reply #22 on: September 26, 2018, 08:29:44 PM »
Hello.
I have some success.
The engine now runs.
I have to hold a small blow lamp near the ignition hole but it runs fine like this.
The pilot light blows out when it fires with the original design.
I am going to look at the design of the ignition hole and make an extra pilot light to relight the original one when it blows out.
How do I attatch a video to the post.
Thanks for the help.
Tony

Offline NickG

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Re: Bruce Atmospheric gas engine
« Reply #23 on: October 21, 2018, 07:52:57 PM »
Interesting stuff, Iíve  never seen one of these running, noticed on the Bruce site that it says acetylene is the best fuel to use, tricky with propane.

Think you need to upload the video to YouTube then paste in the link.


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Offline Zephyrin

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Re: Bruce Atmospheric gas engine
« Reply #24 on: October 21, 2018, 10:17:55 PM »
Hi,
as the opening of the ignition port occurs during the downward stroke, one would have expected that the pilot flame is at first aspirated before being blown by the explosion... maybe the ignition port closes too late, the spring being too hard ?

Offline Tonyr

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Re: Bruce Atmospheric gas engine
« Reply #25 on: October 23, 2018, 05:38:57 PM »
Thanks for the replies
I will look at putting it on YouTube when I get a bit of time.
I am busy decorating at present.
With regards to the flame going out.
You are correct it goes out twice, once when the gas is sucked into the engine and once when it fires.
I am going to change the arrangement of the gas pipe.
I will fit another flame to re light the main one when it goes out.
The second flame or maybe both flames will be will be supplied from a separate supply pipe than the fuel gas which gets sucked into the engine.
Hopefully it will be ok with both gas supplies fed from the same gas canister.
It will be a week or two before I can get back onto it.
Busy in the house and trying to keep up progress on my Austin Seven engine which came to a halt over the summer.
Tony