Combustion researchers worldwide could be about to unlock new levels of efficiency and low cost using breakthrough linear power technology from innovative UK company, Libertine FPE. Its high performance linear electrical machine and gas expander technologies overcome the key challenges of motion control and power conversion efficiency that have held back free piston engine development until now.
Libertine’s technology has the potential to transform the automotive range extender market, power generation, heating, cooling and transport sectors. Comparing a 10kWe portable generator based on Libertine’s technology architecture to the most efficient currently available systems for static power generation shows a saving of 90 percent in package size, 80 percent in weight, significantly reduced cost and up to 30 percent higher efficiency.
“The technology will help our partners create better, smaller generators that produce more power and waste less heat,” explained Libertine’s CEO, Sam Cockerill. “A free piston power module based on our technology could also produce electrical power for range extended electric vehicles and low cost hybrids.”
In a free piston combustion engine, Libertine’s linear gas expander extracts power from the expansion stroke directly in the form of electrical energy. This technology architecture can be applied to many different combustion cycles, and its modular design can be readily scaled for applications from 1kWe to over 100kWe.
“A free piston engine eliminates the entire mechanical drivetrain of a conventional engine, allowing ultra-efficient combustion cycles to be developed and reducing the parts count and cost,” said Cockerill. “It completely removes the crankshaft constraint placed on piston movement that actually hinders efficient combustion, and allows piston motion to be optimised to deliver a cleaner, more efficient combustion process.”
The key to Libertine’s success is a combination of piston geometry, electrical machine design and cylinder construction. All three are relatively long and smaller in diameter than those currently used by free piston developers. This unique architecture reduces the moving mass of the piston relative to the electrical machine’s force, giving more effective and accurate control of the piston motion. This geometry also reduces heat losses from the combustion chamber which, at top-dead-centre, has a much improved surface-to-volume ratio. By integrating the electrical machine into the cylinder wall, rather than attempting to isolate it with seals, the high friction losses often encountered by free piston engine developers are dramatically reduced.
One of the first institutions to invest in the new technology is the Universiti Teknologi PETRONAS (UTP) in Malaysia, which is supported by the PETRONAS oil and gas company. The university has entered a partnership with Libertine, funding a feasibility study that is expected to lead to the supply of free piston research engine hardware upon successful completion.
A leading centre for free piston combustion research, UTP is primarily interested in the combustion process and requires a reliable, efficient linear power system as a platform for its work, according to the university’s deputy vice chancellor for Research and Innovation, Professor Abdul Rashid Abd Aziz. “UTP has an established programme of free piston engine research and development. Building Libertine’s linear power systems technology into our research engine is expected to improve piston motion control and allow us to accelerate our research into high efficiency combustion systems,” he said.
Libertine will be presenting its Linear Power Systems technology to investors at CleanEquity Monaco from 5-6 March 2015 http://www.cleanequitymonaco.com/