Libertine a UK firm was awarded a 2.6 million British pounds or $3,572,543 US dollars to take their free-piston generator concept to commercial production.
Per Libertine web site, the IntelliGEN 20-40 kWe Smart Engine platform is for OEM builders of Hybrid buses, trucks and auto's as well as distributed power applications.
Quoting their web site:
- Robust and flexible platform for lab-based combustion development and prototype validation
- 20-40kWe* two stroke engines with uni-flow scavenging, configurable for light, heavy and gaseous fuels
- Ground-breaking free piston motion control solution for the most demanding combustion applications
- Advanced controls platform and analytics for low temperature combustion methods
- De-risks and accelerates Smart Engine generator product development programmes
This free-piston engine propels magnet-equipped shafts back and forth generating electricity, the design does not produce torque. A big benefit of this motor design is that it can run on a variety of fuels from bio-fuels to renewable alcohol fuels. A small battery pack with efficient onboard generator using 100% renewable fuels Libertine believes is a solution that can drive uptake of net zero trucks before the end of this decade.
This engine concept is not new and has been around since the early 1900's. The solution that Libertine brings to this is the software management and problem solving on how to incorporate this design into a hybrid auto. 1934 is when the first patented free-piston generator happened and these crank less engines have many characteristics that people feel benefit being applied to hybrid auto's.
Free-Piston motors can easily have variable compression ratio for optimized operation. Based on modern computer control allows for variable stroke length by pulse pause modulation control. Frictional losses and manufacturing costs are reduced greatly allowing for less maintenance and increased lifetime. Less lubrication is required due to the purely linear motion also giving much less vibrations due to reduced balancing issues. The advantages of a free-piston engine are pretty clear with them being as follows, simple design with fewer moving parts, giving a compact engine with low maintenance costs and reduced frictional losses. Operational flexibility via variable compression ratio allows operational optimization with multi-fuel. High piston speed and a fast power stroke expansion enhances fuel-air mixing, reducing heat transfer losses and formation of NOx or nitrogen oxides.
gm did considerable research for the time in developing the XP 500 free-piston concept auto. Multiple reasons for not coming to market as management of the motor via software and enhanced controllers was not available then.
Today, Libertine is leaving no stone unturned in finding solutions to help the European Union and the world become fossil free by 2040 for all heavy-duty vehicles as their pledge. The details of the intelliGEN platforms key performance was delivered in a webinar organized by the Institute of Mechanical Engineers.
For more information you can reach out to the company about their various free-piston solutions / uses.
Libertine is not the only company researching the use of free-piston motors. Durham Energy Institute is also looking to use this technology for range extending electric auto's. If costs are able to be kept low, then free-piston range extenders are a potential game changer for fully electric commercial trucks that have big energy needs.
Full details of the Libertine technology can be reviewed here: Technology - Libertine