|The Liquid Piston engine. A) full housing. B) Transparent housing showing principle components. Click to enlarge.|
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 Rankine 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.
|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