Six stroke, steam assisted Listeroid???

[Mr Lister]

Guys,

Got sent this link describing Bruce Crower's 6 stroke engine

http://www.autoweek.com/apps/pbcs.dll/article?AID=/20060224/FREE/60222004/1024

Basically he adds a steam expansion and exhaust stroke AFTER the normal 4 stroke cycle.

The expanding steam removes the bulk of the heat from the cylinder and exhaust.  Remember that in a diesel 1/3 of the fuel energy heats the block and 1/3 ends up in the exhaust.

He claims 40% fuel improvement in fuel consumption and incredibly cool running - all the waste heat ends up in the steamy exhaust.

Bruce Crower is no young upstart - he has been developing cams and engine technology since the late 1940s.


How could this work for us in a Listeroid?  Well remove the idler gear and run the camshaft at 1/3rd engine rpm or alternatively put a timing pulley on the crankshaft and resort to an overhead camshaft run at 1/3rd engine rpm.

The beauty of the Listeroid is that you could squirt the steam into the engine via the compression change valve port.


Think, Induction, Compression, Power, Exhaust, Expansion, Exhaust - that's 6 by my count.

You could use the existing water jacket as a hot well, and take it up to about 95 C, then a monotube boiler coil around the exhaust to boil the water and an external monotube steam super heater.  The existing cam-shaft could be used to drive a feed pump and the injector pump could be used to spray fuel oil into an external burner for the steam superheater.

He even suggests that you could skip the normal IC exhaust stroke and keep the exhaust valve closed - recompressing the exhaust gases, then admit the steam for the steam power stroke.  A final exhaust stroke purges all the steam and exhaust and cleans the cylinder and exhaust of carbon and crap.


Any takers,


Ken

[frostypilot]

Very interesting. Mr Crower discusses the application of the six-stroke engine to mobile powerplants where the need to carry water is a weight problem. For a stationary unit this would not be such an issue and perhaps a side benefit. Any lister would need camshaft reengineering at the very least.

[SHIPCHIEF]

Looks like it might run alittle lumpy until it gets warmed up?
I bet this would work best in a constant load application, like power generation or an oil field pump engine.
Scott E

[Halfnuts]

That's a neat idea.  Water expands about 1244 times going from liquid to vapor assuming no temp. change, and absorbs a lot of heat in the process.  As long as the blowby wouldn't condense in the crankcase oil and cause problems there, this could work. 

[solarguy]

And of course, there have been the "water injection" people who, for decades, have been tinkering with the gassers to add a little water or water vapor to modulate the combustion for improved efficiency and maybe a little extra bang on the water/steam expansion from excess heat.  The gasser is worse than the diesel for energy loss via waste heat.

When somebody works all the kinks out, I'll build one too.

Finest regards,

troy

[SHIPCHIEF]

Water injection was common in the semi-diesel days. It was required to prevent pre-ignition knock and the resultant power loss and engine damage. Rumley OilPull tractors had water circuits in the carburators. Bolinders marine engines used water injection too. It must not have gone into the oil, because those old oils were alot more suceptible to emulsifying with water than modern oils are.
I think the 6 stroke engine would not recover the exhaust steam for pumping back into the boiler. But if it was, then it would have to be cleaned so the exhaust products from cycle 4 and oil contamination would leave scale in the boiler.
Scott E

[Tom]

Seems like you would never have to de-carbon the cylinder head with this process too!