- Tell us about the
new engine, what were you trying to accomplish?
The new engine needed to compliment the motorcycle's design criteria of
a lightweight, versatile Multistrada. We had to deliver a broad
power-band, and aesthetically the engine needed to have an aggressive
look while maintaining certain trademark Ducati architecture. The best
engine to fulfill the menu of requests was a new air-cooled, twin-spark
1000cc engine, based on the best of our existing liquid and air-cooled
engines, but with a new approach and design to increase power,
efficiency and reliability.
- Gianluigi, what are
the main characteristics of the Multistrada family engine?
We're talking about a completely revised engine. The project is based on
the 904cc single cam-shaft Desmodue that power the Monster 900, the 900
SS and the renowned MH900e. It was by no means easy to improve such an
extensively developed engine.
- What approach did
you and your team use in taking on this venture?
We decided to work on two levels at the same time: on the one hand, to
redesign the top ends, that is the cylinder-piston-head assemblies, and
on the other, to optimise the cooling system. The synergy between these
two factors resulted in the creation of a perfect engine for a "total"
bike like the Multistrada; I imagine that the late engineer Taglioni,
creator of the original engine, would have been completely satisfied
with it.
- Can you tell us in
greater detail how you developed the top end of the engine?
As far as the top end is concerned, the design of the Desmodromic head
and of the combustion chamber is new: the angle between the valves has
been decreased from 60° to 56°, whilst maintaining the same tried and
tested rocker arms. The valves are larger in diameter and the stems are
thinner: so the engine can "breathe" better and less heat is transmitted
to the head. The camshafts turn in plain bearing aluminium heads instead
of heavy and cumbersome ball bearings, a solution inherited from the
Testastretta. Also, there are now two spark plugs. The twin ignition
system has various advantages, guaranteeing perfect combustion at any
RPM…lower fuel consumption, lower emissions and a smaller spark advance
angle. Finally, the diameter of the timing pulley, through which the
drive is transmitted to the camshaft from the belt, has increased: the
belt now follows a more direct route.
- What about cooling?
We worked long and hard on studying and improving the heat balance. Heat
flows must be well "matched" in a sound, efficient engine: excessive
temperatures disturb the engine running by causing distortions in the
involved parts, such as the valves, rocker arms, piston and head… A new
rotational casting process has enabled us to obtain an extra cooling fin
on the head, and consequently, better control of the material structure,
especially in the combustion chamber area. An extra cooling fin has also
been added for the cylinder; this has improved the heat exchange in the
cam belt housing area.
- The head and the
cylinder are now connected via a gasket, a sophisticated choice that
allows the contact area between the two parts to be increased, thus
improving the downward heat flow and averting harmful deformations.
Finally, the exhaust pipe has been shortened: this ensures more
efficient heat transmission from the head to the exhaust system.
- How would you
describe the end result?
It's a robust and extremely reliable engine with one litre capacity
(992cc, to be exact), which provides more power and a definite increase
in torque. Road bikes are mostly used at low to medium RPM: for this
reason, we've favoured more torque at low RPM, for total riding
satisfaction.
Ducati Multistrada
Click here for an
interview with director of Ducati Design - Pierre Terblanche |
