The C-Free Tractor
Powering the future: carbon emission-free engines.
C-Free Renew® fuels will power a tractor that has an internal combustion engine that’s been modified to run on hydrogen and ammonia.
The C-Free Tractor is a modified John Deere 7810 with the diesel engine replaced with an 8 cylinder Ford based engine bored to 572 cubic inches (9.3 liter), 13.5:1 compression ratio. It was originally supplied by the Hydrogen Energy Center designed to run on hydrogen gas or hydrogen gas and ammonia.
We planned to use hydrogen as the prime fuel, and found that ammonia combined with hydrogen is a better tractor fuel. The storability, safety, and engine performance benefits out weigh the 50 percent increase in energy needed to make ammonia.
The engine has been extensively modified and upgraded from its as supplied form, adding new spark control, new engine control unit (ECU; the computer that controls the engine) and throttle body injection of the ammonia. These modifications provide much better control of all aspects of the engine and more power. The tractor uses a mixture of 10% hydrogen and 90% ammonia, with the hydrogen used as an accelerator to ignite the ammonia.
Four hydrogen tanks each measuring 20 inch diameter by 10 feet long hold a total of 80 pounds of hydrogen—enough energy to operate the tractor at full power for four hours, if the tractor is operated on hydrogen alone. A small 60 gallon tank at the top front holds enough ammonia energy for two hours.
The use of hydrogen or ammonia provides the energy to operate a tractor with clean, renewable, non-carbon fuels made from sunlight, water and air; which produce no CO2 either in making or burning them. With the C-Free Renew solar-hydrogen-ammonia system producing the hydrogen and ammonia on the farm site to fuel the C-Free Tractor, we’ve essentially created a self-contained farm energy utilization method.
In 2022, the tractor’s fueling and control components were upgraded to improve performance. After discovering that regular injectors leak hydrogen, high performance hydrogen injectors were installed. Previously uncontrolled ammonia gas was mixed into the engine intake air. Two liquid injectors were also installed downstream of the engine throttle body to fuel the engine with ammonia. We found that the ECU could not manage the injection of the two fuels. An additional ECU was added to manage the ammonia injection.
The tractor’s technology is available for license for use in private, custom applications. Please contact us for more information.