DBR Metrics

Power density of a DBR engine is predicted to be significantly high. In a four cylinder 4 liter I.C.E. engine, only one piston contributes power per crank rotation. Hence, if a one liter power stroke produces about 100 hp, we can obtain the following chart comparing displacement density and estimated horsepower.
   functional displacement chart
It is, however, misleading to make a direct comparison. The DBRE completes its power stroke six times per rotation. In other words, the physical chamber volume is displaced every 60 degrees, which essentially means that there is a POWER impulse driving the shaft much more effectively. This directly implies that either the DBRE can operate at one sixth the speed or produce six times the power for a given chamber size. Hence, to correct for this, we use a Function Displacement term which is defined as the volume displaced during one shaft rotation.

With functional displacement charted above, and a volumetric efficiency of only 50%, an engine about the size of a dinner plate can produce over 200 hp!

Operation     Efficency