6-stroke engine?

[diamondlarry]

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

[Matt Timion]

What a cool design.

It seems that the next wave in ICE efficiency will be in recycling wasted heat energy. Just like the "turbo" alternator, using the wasted heat to your advantage is definately a good plan.

[GasSavers_DaX]

Great read and very interesting.

[Bunger]

Wow, that really is cool. When I first saw the title, I thought it was about that guy from down under who had mounted a 2 stroke ontop of a 4 stroke (which i think he was spinning at 18k RPM!). But this is much cooler! (har har, no pun intended)

Damn... thats really got me thinking... lets see, so you have:

1. Intake
2. Compression
3. Power (gas burning)
4. Compression
5. Power (water-to-steam)
6. Exhaust

I wonder what the most efficent engine setup will be. Things will be lighter, as no need for cooling, but you'll have to carry a large supply of water, unless of course you can figure out how to recover the water from the steam... =)

[Sludgy]

Big power plants use a process called "combined cycle": A gas turbine produces power, and the waste heat from the turbine heats a boiler, whcih runs a steam turbine. These big plants achieve upwards of 50% thermal efficiency, much better than gas or diesel* engines.

The problem with making steam with a "6 cycle engine", is the surface area needed. Each HP needs about 10 sq feet of boiler surface. There isn't much surface area inside a car cylinder, so I don't think this idea will pan out. A novel idea though.

*Extremely large engines (like those used in ships) get about 50% efficiency without resorting to exotic combined cycles. Such engines are two stroke diesel engines with a piston about 3 feet in diameter and a stroke of about 8 feet! They only turn at 100 RPM or so. Useless for cars, but I'm fascinated by these behemoths.

http://www.wartsila.com/Wartsila/docs/en/ship_power/products/2str/figures_96c.pdf

[Bunger]

Originally Posted by Sludgy

The problem with making steam with a "6 cycle engine", is the surface area needed. Each HP needs about 10 sq feet of boiler surface. There isn't much surface area inside a car cylinder, so I don't think this idea will pan out. A novel idea though.

Can you explain the boiler surface to HP ratio? I'm very new to the steam power concept. TIA

[Sludgy]

Steam engined can make a lot of power and hellacious torque in small engines. The biggest problem with steam engines is making enough steam.

Each horsepower requires about 10 square feet of surface area. (Fire or hot gas on one side of the tube and water on the other side). So, a 10 HP steam engine needs a boiler with about 40 sq feet of boiler tubes. Assuming 1" diameter x 4 foot tubes, you would need 40 steel tubes. Big boilers are very heavy with all of this water and steel.

Using a "double expansion" steam engine could reduce the amount of boiler surface, but low grade heat would increase it.

[Bunger]

Are we talking requirement or efficiency here? The reason behind the 5th and 6th strokes are to increase the thermal efficiency of a gas engine. Even if 75% of the steams expansion is lost out the exhaust, it may still result in an overall efficiency gain.

Am I on the same page?

[95metro]

Awesome article! That is amazing! Too bad we won't see it on the market for another decade (most likely). Imagine no rad, water pump, and less heat loss. Too bad you have to be a cam wizard to pull it off.

I'm thinking you might need ceramic lining in the engine as well to keep things from possibly rusting?

[95metro]

Sorry, maxc, what are you talking about? You've already got a steam injection system set up in your car?

Come on, man, details! This 6-cycle Crower system is mostly about reducing waste heat so the overall engine runs cooler. Tell us what your steam system is all about!