Enhanced efficiency of internal combustion engines by employing spinning gas

The efficiency of the internal combustion engine might be enhanced by employing spinning gas. A gas spinning at near sonic velocities has an effectively higher heat capacity, which allows practical fuel cycles, which are far from the Carnot efficiency, to approach more closely the Carnot efficiency. A remarkable gain in fuel efficiency is shown to be theoretically possible for the Otto and Diesel cycles. The use of a flywheel, in principle, could produce even greater increases in efficiency.

Figure 1

Otto cycle $1\to 2^{\prime }\to 3\to 4$ and Diesel cycle $1\to 2\to 3\to 4$. Heat is transferred at the $1\to 2^{\prime }$ or $1\to 2$ phase.

Figure 2

Modification of Otto cycle for spinning gas. Dotted red curve is the temperature constraint. Black curve denotes a nonspinning case; dashed blue curve denotes a spinning case.

Figure 3

Efficiency of Otto (solid line) and Diesel (dashed line) cycles as function of spinning parameter $\phi$ at maximum temperature of the cycle for $c_v=2.5$ and $\delta =3/20$. Black: $q=1.75$; green: $q=1.5$; red: $q=1.25$.

Figure 4

Efficiency of Otto cycle vs $\phi$ for $J=1$. Black: $\delta =4/3$, $q=1/2$; dotted red: $\delta =5/3$, $q=2/5$; dashed blue: $\delta =2$, $q=1/3$.