FairDiesel Limited has combined the concepts of barrel and opposed piston engines and applied them to produce an exceptionally well-balanced lightweight diesel engine for a wide range of applications.
The engine is shown diagrammatically, with opposed pistons acting on shaped cams through rollers.
The use of shaped drive cams enables the motion of each piston to be determined independently, unlike a crank-driven engine, and so the combustion cycle can be optimised.
With the pistons at Top Dead Centre, fuel is injected into the compressed air.
Ignition takes place spontaneously and the pistons are driven in opposite directions, turning the cams as they do so. During this power stroke, the cams have identical profiles and so all the thrust is balanced and taken by the drive shaft. The casing experiences no axial thrust at all. Side thrusts from the pistons onto the liner walls are equal, and produce the driving torque.
At the end of the power stroke, the exhaust port opens and the spent gases exhaust to atmosphere via the turbo-charger.
The cams are so shaped that the inlet port then opens and pressurised air from the turbo-charger enters and scavenges away the remaining exhaust gases.
The exhaust port then closes, and air continues to charge the cylinder under the action of the turbo-charger.
The cams then drive the pistons together to compress the air in readiness for the next power stroke.
This compression stroke again uses symmetrical cam profiles to maintain balanced forces on the drive shaft.
Because the cam has four lobes, The complete cycle occurs twice for each revolution of the drive shaft.
Thermal Efficiency
FairDiesel Limited has used the ability to design cam profiles flexibly, to optimise the Thermal Efficiency Performance of the two-stroke diesel engine.
With a conventional crank-driven diesel engine the injection of fuel continues during the power stroke.
Thus full combustion pressure is not generated at Top Dead Centre.
With the FairDiesel Limited engine, the cams are profiled so as to retain the pistons at Top Dead Centre until fuel injection is complete, so that full combustion pressure and temperature are available to drive the pistons along the cylinders, thus maximising thermal efficiency, as in a Spark-ignition engine.
Four (illustrated), six and more cylinder versions of the engine are also planned, with up to 32 cylinders feasible for power generation
http://www.fairdiesel.co.uk/p1.htm
