Honda reveals EXlink engine technology

As the electric motor becomes an increasingly popular alternative for vehicular propulsion, the internal combustion engine hasn't run out of puff just yet.

Honda has revealed its new Extended Expansion Linkage Engine technology, or EXlink for short, which adds an extra pivot point (or trigonal link) between the connecting rod and crankshaft that is designed to improve efficiency.

Likened to the Atkinson cycle engine, which was pioneered some 130 years ago, the EXlink setup's four stroke action is different from a conventional four-stroker in that the extra pivot point allows for different length strokes.

As such, the intake and compression strokes are shorter, while the combustion and exhaust strokes are almost 50% longer (1.4 times longer according to Honda).

The result is improved energy efficieny, and as Honda's press statement reads, it is "The first small engine of its type to be commercially produced," with an "...expansion stroke longer than its compression stroke to realize an expansion ratio higher than its compression ratio."

Got all that?

In simple terms, the engine internals are more complex but allow for improved fuel efficiency.

The engine can use the same amount of fuel as a regular (Otto cycle) four-stroke engine but make more energy with it.

Words don't really do the concept justice, and the best way to grasp how the EXlink setup works is to check out the animations - go to the Honda tech page for the pretty pictures.

The EXlink engine is currently being tested in very small capacity single-cylinder liquid-cooled engines that are being used in generators for household heating. Running on natural gas, the EXlink engine exhaust is also used to heat water for the hot water system.

The Honda EXlink system delivers significant fuel reductions in four-stroke engines, but it remains to be seen if the technology can be reproduced in larger capacity engine blocks.

Though it's unlikely we'll see a Honda CBR600RR with EXlink technology, small capacity scooters might just work. Imagine filling up with 10 litres of fuel and be able to travel 1000 kilometres?

However the addition of more moving parts also throws up the potential of more weak links. Nevertheless, this is an interesting development in the evolution of the internal combustion engine could have a big impact on the future of energy generation.