Just weeks before unveiling Ducati’s brand new 1199 Panigale motorcycle at the EICMA International Motorcycle Show in Milan (10-13 November), the Italian manufacturer has revealed the secrets behind its 2012 superbike.
When designing Ducati’s latest engine, the Superquadro, its engineers were given a design brief to create the new generation Superbike engine for the Ducati 1199 Panigale with more power, torque, user-friendliness, reduced weight and scheduled maintenance costs. Given a blank canvas to create the new powerplant, the innovative Superquadro engine gets its name from its massively over-square bore and stroke ratio. What’s more, it has increased power to a twin-cylinder production milestone of 195hp and 98.1 lb-ft torque. The software will also allow user-friendly Riding Modes that deliver power appropriate to the rider’s style and environment.
The engine’s construction has enabled a reduction in overall vehicle weight and major services have been extended to 15,000 miles.
Only Fabio Taglioni’s masterpiece 90° L-twin configuration and Desmodromic valve control have been retained from previous engines. Everything else is new.
With the engine being a fully stressed chassis member, its architecture has been re-calculated to provide the best construction for layout, weight distribution and strength.
The cylinders, which remain at 90°, have been rotated backwards around the crankcases by a further 6°, until the front cylinder is 21° from horizontal. This has enabled the engine to be positioned 32mm further forwards for improved weight distribution.
The crankcases are vacuum die-cast using Vacural technology to ensure optimal weight saving, consistent wall thickness and increased strength. They also incorporate the outer water-jacket, eliminating the jointing face at the base of the cylinders. Instead, the Superquadro has separate nikasil-coated aluminum “wet-liners” inserted into the top of the crankcase apertures. This design enables secure fixing of the cylinder head directly to the crankcase, improved sealing and enhanced heat dissipation from the thin cylinder-liners directly into the surrounding coolant.
The primary-drive casing, clutch casing and outer cover, sump and cam covers are all cast in magnesium alloy, ensuring a lightweight engine despite its increased strength.
In addition to cylinder position, the crankcases now use shell main bearings for the crankshaft, previously only used by Ducati on the Desmosedici RR engine.
Removing the roller bearings has enabled an increase in diameter of the crank journals for enhanced rigidity and an increase the crankcase section around the main bearing area for improved strength.
The shell bearings are force-fed oil from internal drillings within the main bearing pillars to keep the new crankshaft well lubricated. It is quickly scavenged back into the oil sump with the introduction of a new MotoGP-style vacuum pump.
The pump is driven by the main oil pump shaft and effectively maintains constant vacuum in the crankcase area below the pistons, reducing atmospheric resistance during the down-stroke of the piston and controlling the internal “breathing” of the engine.
In calculating the optimum configuration to achieve the next step forward in power output for the L-twin engine, Ducati and Ducati Corse engineers increased engine speed and enhanced breathing with the incredible bore and stroke of 112x60.8mm. This resulted in an output of 195hp at 10750rpm and 98.1 lb-ft at 9000rpm.
The new bore and stroke ratio of 1.84:1 effectively increases RPM with the ultra-short stroke of the crankshaft and increases the cylinder area to enable increased valves diameters. Inlet valve sizes have increased from 43.5 to 46.8mm, and exhaust valves from 34.5 to 38.2mm.
With such large inlet valves operating at higher RPM, the intense inertial forces have been controlled by using titanium instead of steel, a solution only previously used on “R” models.
The new valves are actuated by racing-derived rocker arms, 'super-finished' for reduced friction and fatigue, and then coated in polymeric-like carbon (PLC), a process originally developed for the aerospace industry.
The race-derived Superquadro pistons have a distinctive double-ribbed undercrown to achieve high strength and reduced friction by using minimal piston wall surface area. Using technology developed by Ducati Corse, the design enables reliable operation of the 112mm-diameter pistons when performing at high RPM.
The improved volumetric efficiency of the increased inlet valve diameters is further capitalized by increasing the oval throttle body dimensions from an equivalent diameter of 63.9 to a high-flowing 67.5mm.
The Ride-by-Wire throttle bodies feed air across twin injectors per cylinder, one positioned below the butterfly for enhanced flexibility, and one above for outright power. With enhanced breathing, the challenge was to program the fuel mapping for a smoother cycle-to-cycle operation without compromising emissions. To achieve this, Ducati introduced a secondary air system that completes the oxidization of unburned hydrocarbons and effectively reduces HC and CO levels.
The system is activated when the ECU recognizes specific conditions via the lambda and throttle sensors. It then opens a valve enabling a flow of clean air from the main airbox to a reed valve situated in each cylinder head, which enables one-way flow into an air gallery exiting into the exhaust port near the exhaust valve.
Entering the hottest point of the exhaust gases, the fresh charge of air enhances the burn environment, eliminating unburned fuel that might escape during the exhaust cycle.
High engine speeds combined with large valves means it would be impossible for the valve’s rocker-arm to follow the cam lobe’s steep closure profile using normal springs. The Desmo system actuates valve closure mechanically with the same method as it opens, enabling steep cam profiles, radical timing, large valves and high operating speeds. This system is used on every Ducati motorcycle and is constantly proven on Ducati Corse World Superbikes and Desmosedici MotoGP bikes.
Controlling such large valves with the Desmodromic system also led engineers to replace the original belt-drive concept, used since the introduction of the Ducati Pantah in 1979, with a combined chain and gear-drive arrangement.
The conventional bush-type chain runs from the crankshaft to the cylinder head where a single sprocket positioned between inlet and exhaust camshafts, is attached back-to-back to a gear wheel mounted on its own short shaft.
The attached gear meshes directly with gears on the ends of both the inlet and exhaust cams, which are also designed with +/- adjustment for ultra-precise cam-calibration.
On the end of each exhaust cam drive gear is a centrifugal flyweight which retracts at speeds below tick-over to rotate a “protrusion” from the concentric section of the cam, thus creating sufficient inlet valve lift to act as a de-compressor.
This device enables the Superquadro to be started without using a larger battery and starter motor, which has reduced overall weight by approximately 7.3 lb. When the engine starts and the camshafts begin to rotate at idle, the centrifugal flyweight flicks out, retracting the “protrusion” back into the cam and allowing complete valve closure for full compression.
Ducati’s engineers also increased the dimensions between the centers of the six-speed gearbox shafts, enabling larger diameter, stronger gears to transmit the power.
New for a top-of-the-range Ducati Superbike is a “wet”, oil-bath clutch. Based closely on the design of the Multistrada and Diavel components, the clutch assembly features a “slipper” function and a progressive self-servo mechanism that compresses the friction plates when driven by the engine.
While enhancing frictional efficiency, this also results in a rider-friendly light clutch lever at the handlebar. Conversely, when the drive force is reversed (over-run), the mechanism reduces pressure on the friction plates, enabling a true racing “slipper” action, reducing the destabilizing effect of the rear-end under aggressive down-shifting and providing a smoother feel when closing the throttle or down-shifting under normal riding conditions.