I went on a plane trip from Los Angeles to Minneapolis, and while I was waiting in the terminal I picked up a copy of the Economist to read. In the Economist’s Technology Quarterly, there is an article called Powering Up, that explains how to make airplane engines more efficient.
The Economist reports that modern airplane engines use about half as much fuel as the first jet engines did, but there is still a way to reduce their fuel consumption by another quarter. David Lior of R-Jet Engineering is building engines that have spinning rotors in their combustion chamber. Engines have fans that rotate air, but usually these are only in the compressor, which is in front of the combustion chamber. NASA provides an explanation of each part that makes up the airplane turbine. Notice that their example of the compression chamber does not contain rotors or fans, although several sections of the engine do. When the rotors circulate the air, it ensures that the fuel and air mixture steadily mixes throughout the chamber, ensuring that all of the fuel ignites so no fuel is wasted. This not only conserves fuel, it reduces combustion because complete combustion reduces the amount of smog and acid rain caused by byproducts that do not completely burn.
R-Jet would like to place these turbines in jet planes, but this new type of engine will require demonstration of its safety before the airlines will purchase an engine with this type of combustion chamber to use in a passenger jet. R-Jet’s plan involves using this technology to operate wind turbines, since a failure of a single turbine would not be critical if it occurred in a farm with a thousand turbines. The other demonstration use of these engines is in unmanned drones, such as Predator drones. If these crash it costs the military a lot of money, but it wouldn’t kill a pilot or any passengers. Since this orbital combustion nozzle technology reduces fuel capacity requirements, it could also increase the range of a missile.
According to Globes Online, airplane engines are much more efficient than car engines, but only at high speeds. Inventors at the firm Newton Technologies created an engine that combines the best efficiency aspects of the traditional combustion engine and the airplane engine. This combination engine is much smaller than the engines in most vehicles, greatly reducing the material requirements to build a car engine. A larger engine that produces much more horsepower than cars normally have would still easily fit in a car. The inventors also mention that this type of hybrid engine can burn many types of fuel, including biodiesel, without additional modifications.