A V4 for the future of Ducati sport bikes
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A V4 for the future of Ducati sport bikes
[Image: ducatimediahdr.jpg]

The Ducati Desmosedici Stradale is born from the heart of the Ducati Desmosedici GP and now is ready to turn its power and excellence into pleasure for all roadgoing sportbike enthusiasts. Unique, light, compact, technically advanced, with an unmistakable sound.

An engineering masterpiece, capable of bringing together the smooth power delivery of its V4 with the racing attitude and the strength more of its 210 Cv.

V4 90°

For Ducati, the V4 layout at 90° is the utmost expression of sportiness for a motorcycle engine. It is no coincidence that it is the same solution used in the MotoGP Desmosedici engines. The 90° V layout of the cylinders creates a natural balancing of first-order forces without the need to resort to a balance shaft to eliminate the vibrations that notoriously entail increases in weight and power absorption. In addition to this primary benefit, which is extremely important for the reliability and mechanical efficiency of an engine that reaches rotation speeds greater than 14,000 rpm, there are others that make the configuration chosen by Ducati the most technically refined.

[Image: ducatiV4-1.jpg]

Desmo: blending tradition and the future

The new engine is designed around the Desmodromic system, a characteristic that helps make Ducati the fastest prototypes of the top racing class in motorcycle racing. With this high-rotation engine the "Desmo" achieves its maximum technical value, reaching levels of sophistication, compactness and lightness never seen before on a Ducati.

Counter-rotating crankshaft

On street bikes the crankshaft rotates in the same direction as the wheels. In contrast, in MotoGP the counter-rotating crankshaft that rotates in the opposite direction is commonly used. The Desmosedici Stradale has borrowed this technical solution to compensate for part of the gyroscopic effect produced by the wheels, making the bike more agile and precise when changing directions. The counter-rotating crankshaft also generates a torque due to inertia that tends to lower the front end during acceleration, and the rear end when braking, thus reducing the wheelie phenomenon.

[Image: ducatiV4-2.jpg]

"Twin Pulse" firing order

The crank pins, offset by 70° like on the Desmosedici GP, require a "Twin Pulse" firing order to generate power that is easy to handle and optimise traction when coming out of curves ("Big Bang" effect). Thanks to this firing order the Desmosedici Stradale makes a unique and distinctive sound.

MotoGP performance

The Desmosedici Stradale was developed to combine racing performance with all the necessities for road use.

To maximise mid-range torque - so important for the enjoyability of motorcycles on roads open to traffic - and to achieve torque and power at slower speeds, the engine has a larger displacement than the MotoGP version, specifically 1,103 cm³. It delivers a power output of more than 155 kW (210 hp) at 13,000 rpm and a maximum torque of over 120 Nm (12.2 Kgm) from 8,750 to 12,250 rpm in the Euro 4 version

Road and Track

The bore of (81 mm) is the same as that used by the Desmosedici GP engine and is the maximum dimension allowed by MotoGP regulations. It is also the highest in the four-cylinder supersport segment.

The stroke (53.5 mm) is longer compared to the Desmosedici GP engine in order to deliver higher torque on open road use, and to reduce maximum engine rotation speed.

The use of the same bore as the Desmosedici GP engine means that all the fluid dynamics (valves, intake pipes, throttle bodies), which in fact make up the heart of the engine where the performance is generated are also very similar in the two drive units.

Racing architecture

The V4 90° layout makes the engine extremely compact, allowing the centring of the masses and better integration into the bike. In fact, the Desmosedici Stradale has been inserted into the vehicle with the front bank of the cylinders rotated back by 42° with respect to the horizontal plane, as on the Ducati engines competing in MotoGP. This optimises the distribution of weight, allows for the use of more extensive radiators and makes it possible to shift the swinging arm pivot forwards.
Its architecture also generates a natural balancing of first-order forces, without the gain in weight and loss of power of a balance shaft.

[Image: ducatiV4-3.jpg]

Variable height intake funnels

Variable height intake funnels optimise cylinder filling at all rotation speeds with important benefits in terms of power and rideability. The fuel supply system is thus completed by oval throttle bodies, each with two injectors: one below the throttle and the other above.

Maintenance

Starting from the Desmosedici GP engine, the manufacturing technologies, the materials and the auxiliary components layouts have been modified to achieve the required road durability, achieving standard maintenance intervals of 24,000 km (Desmo Service), Euro 4 homologation and high production capacity.


An R version with a displacement of less than 1000 cc - which revs higher and is intended more for track use - is currently at the advanced development stage. This will provide the foundation for the homologated version that competes in the Superbike championship, where this engine will be used starting in 2019 (one year on from the launch of the respective road version, as per the Ducati tradition).

RACING DNA

V engine

For Ducati, the V4 layout at 90° is the utmost expression of sportiness for a motorcycle engine. It is no coincidence that it is the same solution used in the MotoGP Desmosedici engines. The 90° V layout of the cylinders creates a natural balancing of first-order forces without the need to resort to a balance shaft to eliminate the vibrations that notoriously entail increases in weight and power absorption. In addition to this primary benefit, which is extremely important for the reliability and mechanical efficiency of an engine that reaches rotation speeds greater than 14,000 rpm, there are others that make the configuration chosen by Ducati the most technically refined.

Compactness

Compared to a classic in-line four-cylinder, the lateral compactness of the V-engine allows greater centralisation of the masses and makes it possible to limit the weight on the front end of the bike. Furthermore, the shorter crankshaft generates a smaller gyroscopic effect. All these aspects have a positive impact on the bike's dynamics, helping to make it light and fast when changing directions. The large space available between the V of the cylinders made it possible to position the water pump and have a large volume airbox (12.8 litres) to allow the Desmosedici Stradale to breathe better.

Integration of engine and chassis

The optimal integration of engine and chassis is a fundamental concept behind every Ducati project. That is why the Desmosedici Stradale was developed to be mounted rotated backwards by 42°, like the Ducati MotoGP engines, to optimise weight distribution, use more extensive radiators and to shift the swinging arm pivot forwards as much as possible.

The Desmosedici Stradale was also designed to be a structural element of the frame. Connections to the main frame were added to the front of the upper casing and in the head of the rear bank. The engine block also acts as a connection for the rear suspension and swinging arm.


FEATURES

Desmodromic system 1/2

Like all Ducati engines, on the Desmosedici Stradale the design of the Desmodromic system is a key factor for obtaining top performance. The Desmodromic system in the Desmosedici Stradale uses components that have been completely redesigned and miniaturised to obtain very compact heads, achieving a level of sophistication, compactness and lightness never seen before on a Ducati bike. Each component of the system was designed and tested to safely reach the rotation speeds the V4 is capable of achieving. Also contributing to the compact engine heads are the new spark plugs, smaller than the standard model currently in production.

The four camshafts of the Desmosedici Stradale engine move the 16 steel valves, the intake valves having a diameter of 34 mm and the exhaust valves measuring 27.5 mm in diameter, quite large in relation to the 81 mm bore adopted. The valve seats are made of sintered steel.

Desmodromic system 2/2

Given the V4's high rotation speeds and the large size of the valves, the latter could not follow the cam closure profiles using a traditional spring system. This is why the Desmodromic system becomes indispensable. In Ducati's "Desmo" the valves are mechanically closed with an accuracy similar to that of the opening phase, making it possible to realise more pronounced cam profiles and extreme timing that optimise the dynamic flow of fluids both during intake and exhaust and therefore greater performance of the engine.

The camshafts are controlled by two “silent” timing chains. On the front timing system the chain drives the intake camshaft, which in turn transmits motion to the exhaust via a pair of gear wheels (mixed chain-gear timing system). On the rear timing system, on the other hand, the chain drives the exhaust shaft which transmits motion to the intake line. This choice minimises timing absorption, benefiting performance and reliability. The chain that controls the timing of the front cylinders is positioned on the right side of the engine and is driven by the crankshaft through a gear on the sprocket of the primary transmission. The one that drives the rear cylinders is situated on the left side of the engine and is driven by a gear that is part of the crankshaft. Each head has an "anti-beat" sensor that makes it possible to optimise the management of advance firing, avoiding knocking phenomena.


MATERIALS

Magnesium: precious alloy

Magnesium occupies a prominent position among the lighter metal materials. It is not by chance that in alloy form it is widely used in competitions. The Desmosedici Stradale uses magnesium alloy for numerous components, including head covers, oil sump, generator and clutch. A technical choice that also has a positive impact on the bike's look.

Aluminium: durability and lightness

The crankcases are made of aluminium using gravity die-casting and coupled with horizontal cut. The upper casing includes the four aluminium cylinder liners with nikasil coating that ensures low friction and protection against wear.

LIGHTNESS AND COMPACTNESS

Weight

The collaboration with Ducati Corse has made it possible to achieve a compact, lightweight and high performance engine. Weighing 64.5 kg, the Desmosedici Stradale is only 2 kg heavier than the 1,285 cm³ twin-cylinder Superquadro.

Pistons

Pistons having a diameter of 81 mm churn in the barrels of the cylinders, with two piston rings, low friction, plus oil scraper ring. They are moulded in aluminium and utilise the "box in box" technology that makes it possible to contain the skirt height and the thickness under the piston crown thus reducing friction and inertia loads while maintaining the required durability and stiffness.

Compression ratio

The compression ratio is 14:1, a high value that once again reflects a design of competitive origin. The pistons are coupled to steel forged rods with a centre distance of 101.8 mm.

GEARBOX AND CLUTCH

DQS Up & Down: changing gears like in a race

The perfect functionality of the six-speed gearbox is enhanced by the Ducati Quick Shift EVO (DQS EVO), which offers a fundamental evolution: changing gears with the throttle open. Furthermore, DQS EVO follows different logics to shift up and down. Integration with the slipper clutch and engine brake (Engine Brake Control) ensures the system's absolute effectiveness even on the track.

Slipper clutch

The wet clutch with progressive control optimally combines high torque drive and rider comfort. In competitive riding conditions, with sudden downshifts and strong engine braking, the slipper clutch counteracts the loss of stability of the rear end, offering excellent control while braking deep in corners.

DYNAMIC FLUID

Semi-dry casing lubrication

Like the MotoGP engines, the Desmosedici Stradale uses a semi-dry casing lubrication with delivery and recovery stages to ensure proper lubrication of all moving parts at all times.

The oil pump, driven by a chain, consists of four stages, one for lobe delivery and three for recovery, one with gears to draw oil from the heads through two ducts, while the other two pumps have lobes and ensure effective recovery of lubricating oil in any condition of engine use, while maintaining the engine crankcase underneath the pistons under controlled constant vacuum conditions, reducing losses due to ventilation, that is, the power absorption caused by the aerodynamic resistance offered by the air and the beating of the oil present in the connecting rod compartment.

The oil tank, which also serves as a filter housing, is situated in a magnesium oil sump mounted under the crankcase and connected to the gearbox compartment, but separate from the crankcase. For cooling the oil a dedicated radiator is used, secured below the water cooler.

Cooling system

The water pump, located in the V of the cylinders, is powered by a shaft driven by a cascade of gear wheels. Its location is designed to reduce the size of the circuit as much as possible, improving its efficiency and optimising engine weight.


HOMOLOGATION

MotoGP technology and regulatory compliance: the Desmosedici Stradale is Euro 4 approved.

*(Only for countries where Euro 4 regulations are applied)
08-09-2017, 01:59 PM
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