"Cé hé sin" (michael-m-mouse)
07/09/2015 at 17:38 • Filed to: Two stroke, Hot bulb
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"Cé hé sin" (michael-m-mouse)
07/09/2015 at 17:38 • Filed to: Two stroke, Hot bulb | 3
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Today’s two stroke doesn’t go on the road.
Meet Harry.
Harry is a tug, built in 1887 and almost entirely renewed in 1950 when she (he?) was fitted with a Skandia hot bulb two stroke engine producing about 300 hp. To produce this power required an engine of 120 litres weighing about 14 tonnes. Not many hp/litre then, but very large marine diesels today aren’t much better.
What’s a hot bulb engine? It’s a thing that was very popular in Sweden in the first half of the 20th century and is neither spark nor compression ignition. Instead you heated a prechamber called a hot bulb with a blowtorch until it was hot enough to maintain ignition. Once the engine was running the heat it produced would all going well keep the bulb hot enough. Simple, reliable, relatively easy to start and hideously inefficient.
Picture by Peter Langsdale.
Brian, The Life of
> Cé hé sin
07/09/2015 at 17:47 |
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So .. How did they turn off a hot bulb engine? Fuel cutoff?
Roadster Man
> Cé hé sin
07/09/2015 at 17:49 |
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Whoa whoa whoa, I need a sweet diagram to visualize how this type of engine works. That is so cool!
And I wonder how sketchy it was to be the guy heating up the chamber... I’m picturing a large Swedish guy with a blowtorch.
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Cé hé sin
> Brian, The Life of
07/09/2015 at 18:12 |
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Yes, same as a diesel.
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Cé hé sin
> Roadster Man
07/09/2015 at 18:18 |
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Here we go. The red area marked 1 is the hot bulb. Air and fuel was pushed in by the piston as it rose and was ignited by the heat. The mixture then expanded out into the volume above the piston and pushed it down.
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Roadster Man
> Cé hé sin
07/09/2015 at 18:31 |
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That is super cool! Seems inefficient, but I’m no engineer.
desertdog5051
> Cé hé sin
07/09/2015 at 19:38 |
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Can’t foul a plug if you don’t have any. I know a guy who has that in a tug he keeps on Lake Michigan. Very different.
You can tell a Finn but you can't tell him much
> Cé hé sin
07/10/2015 at 15:41 |
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What type of fuel does it use?
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Cé hé sin
> You can tell a Finn but you can't tell him much
07/10/2015 at 16:34 |
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Just about anything of poor quality that burns. That was one of the advantages of the hot bulb engine. Waste engine oil, paraffin, creosote, fuel oil. They didn’t do so well on more refined fuels like diesel.