(FairDiesel has changed its name -Site still under construction)
Low carbon, low emissions engine for automotive, aviation, marine and industrial applications.


The Covaxe engine

Covaxe Limited combines the axial and opposed piston engine architectures and applies new patented concepts to them to produce an exceptionally efficient, well-balanced lightweight engine with inherently low emissions 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, in which the piston motion is constrained to be virtually sinusoidal, and so the combustion cycle can be optimised.

Because the cam has four lobes, The complete cycle occurs twice for each revolution of the drive shaft.


Thermal Efficiency

Covaxe Limited uses the ability to design cam profiles flexibly, to optimise the thermal efficiency of the two-stroke compression-ignition engine.

With a conventional crank-driven compression-ignition engine the injection of fuel continues during the power stroke as the pistons move down the bore, or, in the case of an opposed-piston engine, as the pistons move apart.

Thus full combustion pressure is not generated at Top Dead Centre.

With the Covaxe Limited engine, the cams are profiled so as to maintain a constant combustion volume until fuel injection and combustion is complete, so that full combustion pressure and temperature are available to drive the pistons along the cylinders, thus maximising thermal efficiency. The engine combines this thermal efficiency advantage of a spark-ignition (gasoline) engine with that of a higher compression ratio engine. The combustion regime thereby reduces CO2 emissions, but can also be tailored to significantly reduce particulate emissions thus combining the advantages of gasoline and compression-ignition engines.

The illustration below shows a four-cylinder engine although our current baseline engine has seven cylinders.


Covaxe Limited 's use of the opposed-piston arrangement ensures that the forces within the engine are balanced to produce a quiet engine with exceptionally low vibration and even torque delivery without the need for a large heavy flywheel.

Simplicity and Maintainability

In addition to the significant emissions reduction, a striking feature of the cylindrical profile engine is the mechanical simplicity, with far fewer parts than an equivalent engine. Furthermore, the axial combustion forces are carried by the central shaft enabling a lightweight casing. We believe that the engine will therefore be very competitive in terms of price and weight per unit power output.

Covaxe Limited employs a patented modular cylinder assembly approach which enables ready access to main components for maintenance purposes, without having to totally dismantle the engine.

The engine is made in modular form for ease of manufacture and assembly.