MINIMISES ENGINE WEAR.
For its size, Dtorque’s unique 800cm3 reciprocating two-cylinder diesel powerhead design produces an impressive 50hp. More important is its 111Nm torque output, which outstrips that of most of the latest 70hp petrol outboards on the market. But what’s most impressive is minimal vibration.
The secret behind that is the company patented ‘Spaceball’ design. The aluminium cylinder block houses dual crankshafts which rotate in opposite directions to absorb the considerable vibration that a conventional small two-cylinder diesel engine would normally generate.
For the user, the benefits are immediately apparent. Less vibration, less noise, and lighter boat handling without having to continually wrestle with the tiller to correct for torque steering all mean less operator fatigue – and less stress on the engine, too.
The engineering refinement doesn’t end there. Common-Rail fuel injection — rare indeed in diesel engines as small as this one — and turbocharging with integrated charge air cooling are just two of a list of features which contribute to performance, fuel saving and lower emissions.
All of the moving parts of the vertically-mounted Dtorque engine are clearly seen in this CADCAM screen display. Central to the assembly are the dual crankshafts with their miniature counterrotating flywheels. Light weight connecting rods are connected to crankshafts by two inline pistons, while aspiration is provided by four camshaft-driven valves per cylinder.
This two-dimensional diagram shows clearly how the two reciprocating pistons complement each other at the full extent of their up and down strokes. It may look simple, but the asymmetric engine cycle with its short compression stroke, longer intake stroke and shorter expansion stroke required particular attention from the Dtorque engineering design team. The benefit, however, is improved thermal efficiency with an extended piston work stroke.
The end result of Dtorque´s engineering design and development work is a remarkably neat and compact engine package, as seen in this overhead rendering. As in the tradition of the finest Swiss mechanical watch making, all of the vital components fit together with in a beautifully elegant and intricate symmetry.