Pneumatic motor from the expansion of the gas. These days, using the patent pending 'K'Air Generator', converted to work as a compressed-gas motor, the project should be launched in 2010, thanks to a North American group of investors, but for the purpose of developing first a green energy power system. In the original Nègre air engine, one piston compresses air from the atmosphere to mix with the stored compressed air (which will cool drastically as it expands). This mixture drives the second piston, providing the actual engine power. MDI's engine works with constant torque, and the only way to change the torque
Potential energy positive work is a reduction in the potential, that is where "C" is the trajectory taken from A to B. Because the work done is independent of the path taken, then this expression is true for any trajectory, "C", from A to B. The function "U"(x) is called the potential energy associated with the applied force. Examples of forces that have potential energies are gravity and spring forces. In this section the relationship between work and potential energy is presented in more detail. The line integral that defines work along curve "C" takes a special form if the force F