Posted on 07/31/2007 5:57:28 AM PDT by Red Badger
The Liquid Piston engine. A) full housing. B) Transparent housing showing principle components.
LiquidPiston, developers of a new engine architecture they claim will achieve 50% fuel efficiency (compared to the ~30% of existing engines) and drastically reduce pollutant emissions (earlier post), closed a $1.25 million seed investment round with Adams Capital Management and Northwater Capital.
The architecture is based on a “High-Efficiency Hybrid Cycle” (HEHC) thermodynamic cycle, which borrows elements from Otto, Diesel, Atkinson and Rankin cycles. The HEHC cycle can be implemented in a variety of ways; LiquidPiston is developing an implementation that uses a separate rotary compressor, two isolated combustion chambers, and a separate rotary expander. Hehc The HEHC cycle. Click to enlarge.
In the HEHC cycle (diagram at right), air (with no fuel) is compressed to a high ratio (> 18) in a compressor cylinder of the engine. The air is directed into an isolated combustion chamber. Fuel is injected into the combustion chamber and auto ignites. Combustion occurs under truly isochoric conditions and is allowed to complete until all fuel is fully combusted. The combustion products expand into an expander cylinder, which has larger volume than the intake volume. A small amount of water (an optional component) may be used in the system. Water may facilitate the cooling, lubricating, and sealing of combustion chamber and pistons.
Earlier this year, the company announced a $70,000 Phase I grant from the Army Small Business Innovation Research (SBIR) program. The father-son team led by immigrant physicist Nikolay and his son Alexander Shkolnik, a graduate student in MIT’s department of Electrical Engineering & Computer Science, will use this latest $1.25 million seed round of venture capital to build and test a working prototype.
Aside from significant improvements in fuel efficiency, LiquidPiston’s approach to ICE design has the potential to result in a substantially higher power-to-weight ratio, fewer moving parts leading to higher reliability and lower maintenance costs, and significantly lower emissions. The company expects to demonstrate a working prototype in the next 18 to 24 months.
The potential of this technology is tremendous, and the interest we are seeing from both the public and private sectors is very encouraging. With this latest round of investment, LiquidPiston is on its way to achieving its goal of revolutionizing the $250 billion market for internal combustion engines. —Dr. Ed Crow, retired senior vice president of Pratt & Whitney and an advisor to LiquidPiston
That IS COOL!........
I’d guess that Japan Inc is doing some serious development work with that MYT engine at present. It’d be asking too much for Detroit to be interested.
That MYT engine looks to me like it should work as advertised and the only caveat I’d make is that for the kinds of power output per size they’re talking about, some of the parts might have to be hardened like tool or gun metal. One problem they must have experienced is a lot of people being gun-shy about such things because of a similar sounding attempt in the mid 90s which for whatever reason never went anywhere. That would be the so-called split-cycle engine and, to my thinking, there is no real similarity.
I was looking at those “compression” and “expansion” rotary thingmebobs in their drawing. To hold compression or expansion, those would need seals, yes?
That’s the tough part. They need to have it seal on two dimensions of the rotor: along the vertices of the rotor and also along the flat sides.
On a cylindrical piston engine, ring-shaped seals do the trick.
Um.... yeeaaaaaaaa, according to Mazda’s marketing department.
Actual rotary engine owners, however, seem to have differing definitions of “fixed” from the manufacture(s). I’ve had more than one friend with a RX-7 who, after a seal tear-down and then an engine replacement, decided that however neat, cool and wicked fast the RX-7 with a Wankel was... it simply cost too much to keep running.
Mind you, I think that the Wankel concept is cool. The seals, however, give engineers fits in several ways - how their mating aspect angles change throughout the cycle, materials failures, spring pressure failures, blow-by, etc.
The failure rate of apex seals vs. the failure rate of rings in a piston engine pretty much tells the story that they’re still not in the same reliability/longevity ballpark as recip engines.
Thanks for refreshing my memory. That is actually one of the ones that I was thinking of. There is another one that has pistons in sleeves.
The wankel was too heavy and too hard to do anything to without taking it all the way apart. Weight translates into efficiency (or lack thereof) at some point.
No Rx7 or Rx8 owner I know had any problems well over 100000 miles.
Your comment about spark plug demise is ironic in light of NASA research:
[clip NASA e-mail article]
DRIVING CLEAN
Researchers at MIT have demonstrated how ordinary spark-ignition car engines can, under certain driving conditions, move into a spark-free operating mode that is more fuel-efficient and cleaner. The new capability could be available in production models within a few years, improving fuel economy by several miles per gallon. Over time, it could cut oil demand in the U.S. by a million barrels a day.
Switching a spark-ignition (SI) engine to homogeneous charge compression ignition (HCCI) mode pushes up its fuel efficiency. In an HCCI engine, fuel and air are mixed together and injected into the cylinder. The piston compresses the mixture until spontaneous combustion occurs. The engine combines fuel-and-air premixing with spontaneous ignition. The result is that combustion occurs simultaneously at many locations throughout the combustion chamber.
Using the results of their engine tests as a guide, the researchers developed an inexpensive technique that should enable a single engine to run in SI mode but switch to HCCI mode whenever possible. A simple temperature sensor determines whether the upcoming cycle should be in SI or HCCI mode.
The researchers estimate that the increase in fuel efficiency would be a few miles per gallon, which may not seem like an impressive improvement, but, according to the team, if all cars in the US improved that much, it could be worth a million barrels of oil per day, which is impressive.
Read the full story at:
http://link.abpi.net/l.php?20070731A2
[end NASA article clipped from e-mail]
But - it would still be the basic engine, with improved computer controls. Same manufacturing technology, etc. (Maybe some improvements, like ceramic coatings on the top of the pistons and the heads, to allow higher temperatures (without overheating the pistons/block/heads.)- Higher temperatures would probabl make the cycle more efficient!
Mike
Already been posted on FR.........by me.......
On Homogeneous Continuous Compression Ignition, of HCCI for short.
Toyota (and Ford) call it Controlled Auto Ignition, or CAI.
GM is working feverishly on it and will have proto's to drive next year, go here for the story:
http://www.sae.org/automag/techbriefs/02-2007/1-115-2-22.pdf
It has been the subject and hot topic of many SAE papers and symposiums the last few years.
Think of it as the weight of a piston engine with almost the fuel economy of a diesel that works good on low octane fuel.
It works in a narrow band, fuel economy can increase as much as 40% and emissions drop 80%.
In my opinion it is the "Holy Grail" for engines and will make diesels boat anchors. The question has been asked on the Green Car Blogs, will GM try to incorporate HCCI into the "Prime Mover" engine on the "Volt". Since it will run at steady state, you could potentially set it up to stay in the HCCI mode all the time. If they do, Katie Bar the Door....
In my opinion, the fuel to watch, Propane....
Also a very interesting technology you may want to google: "Spark Ignited Heavy Fuel"
More later....
I saw something on the science channel about an engine that used water inside the cylinder for cooling but the stream created was used to create another power stroke, after combustion at the end of the exhaust stroke a small amount of water was sprayed into the cylinder the resulting steam created the extra power and increased fuel efficiency
not sure if it was the same thing
Bump for later.
I don't so.
Check out SEHF here:
http://www.hirth-uavengines.de/Download/Download.htm
Read anything that says Heavy Fuel.
here it is
it was popular science
its a six stroke, 4 gas powered 2 steam powered
http://www.popsci.com/popsci/technology/c1609351d9092110vgnvcm1000004eecbccdrcrd.html
Crower calculates that the Steam-o-Lene boosts the work it gets from a gallon of gas by 40 percent over conventional engines.
Looks kinda like a positive displacement blower.
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