The HDT motorcycle diesel engine is based on state-of-the-art high-speed automotive diesel engine technology, engineered into a complete power unit suitably sized and packaged for installation in a compact on/off road motorcycle.

The basis of the design is a technology demonstrator program for a motorcycle diesel engine carried out by Cranfield University in the United Kingdom.

The aim is to produce the best possible power and torque without the need for turbocharging. To achieve good power, an advanced, thermally robust, free-breathing four valve cylinder head is used, in combination with an indirect injection combustion system and intensive development and tailoring of the fuel injection characteristics. Indirect injection also gives lower combustion pressures – enabling lighter engine construction, less ‘diesel knock’ and low particulate emissions.
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The engine is of conventional mechanical design, optimized for this particular application. Lightweight reciprocating components give minimum vibration and reliability is assured by good design, high duty materials and advanced manufacturing techniques.

A deliberate decision was taken to use mechanically controlled fuel injection for the current engine, employing a purpose-designed injection pump. For the future, electronic control will allow further enhancements in performance. The engine is capable of operation on either diesel fuel (mineral and bio-diesel) or aviation kerosene.


The result is a simple, compact, lightweight power unit of more than twice the specific power output of conventional small diesel engines.

The usable engine speed range is also much greater than other diesel engines. Peak power of some 50 hp/litre is developed at around 5800 rev/min, with usable power available up to well over 6000 rev/min. This is combined with excellent low speed torque in a way which is unique for a diesel engine. The motorcycle thus has outstanding drivability with less need for gearchanging, which aids both on-road enjoyment and cross-country performance in the hands of expert and less experienced riders alike.

The technology is immediately transferable to other applications requiring small, lightweight,
high speed diesel engines.


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