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Ducati creates most powerful single-cylinder road engine

Ducati Superquadro Mono. [Credit: All images courtesy Ducati]

 

 

High-performance Italian motorcycle maker Ducati says its new Superquadro Mono is the most powerful single-cylinder engine in the world, besting by far its legendary Supermono 550 engine of 30 years ago. The 659-cc Superquadro Mono features a Desmodromic system and was created by choosing refined materials and solutions for each component.

The new engine will equip a yet-to-be-revealed new Ducati bike as part of a Ducati world premiere event on Nov. 2. Ducati says the new engine will also be used on motorcycles "for A2 license holders in a detuned version."

The Superquadro Mono delivers a maximum power of 77.5 hp at 9,750 rpm and is capable of reaching 10,250 rpm, values that Ducati says have never been achieved before by a road single-cylinder engine. According to Cycle World, torque peaks at 46 lb-ft at 8,000. The torque has a maximum value of 6.4 kgm at 8,000 rpm. In racing configuration with Termignoni exhaust, this single-cylinder is able to reach a max power value of 85 hp at 9,500 rpm.

The single-cylinder powerplant is based on the Panigale 1299 engine, the 1,285-cc Superquadro, which represents the maximum evolution of the Ducati street-legal twin-cylinder. The Superquadro Mono inherits the 116-mm diameter piston from the Panigale engine, the shape of the combustion chamber, the 46.8-mm diameter titanium intake valves, the 38.2-mm steel exhaust valves, and the Desmodromic system (which is a reciprocating engine poppet valve that is positively closed by a cam and leverage system rather than a spring).

The name Superquadro comes from the extreme ratio between the bore and very short stroke that allows for rotation speeds typical of racing engines. On the Superquadro Mono, this ratio is equal to 1.86 and is the most extreme in the category thanks to a stroke of just 62.4 mm. The record bore of 116 mm allows the adoption of large-diameter valves to benefit performance, which would not be possible without the Desmodromic system. This system, which Ducati also uses on the MotoGP bikes, "allows the limits imposed by the valve springs to be overcome," enabling extreme valve lift. In this way, the Desmodromic system contributes significantly both to performance and to reaching very high rotation speeds.

Ducati says the 116-mm bore piston "is an absolute record for a production single cylinder." It features a "box in box" layout like the pistons of the Panigale V4 R -- a double-truss base that combines rigidity and resistance by reducing the thrust surfaces to rein in friction. Additionally, the piston pin is equipped with a Diamond Like Carbon (DLC) surface coating, the same treatment used for the piston skirt of the Panigale V4 R. The compression ratio is equal to 13.1:1. As on the Desmosedici MotoGP engine, the rocker arms of the Desmodromic system also make use of a DLC surface coating to reduce friction and increase resistance to fatigue. Distribution is controlled through a mixed "silent" gear/chain system.

Fuel feed is handled by a single oval-section throttle body with a diameter of 62 mm, with an under-throttle injector controlled by a ride-by-wire system that offers three different power modes: high, medium, and low.

The die-cast engine crankcases integrate the water jacket around the cylinder barrel and are made just like those on the 1299 Superleggera but in aluminum rather than steel. Big benefits come in terms of weight and cooling due to the thinness of the walls. This solution also allows the head to be fixed directly to the crankcase, obtaining a much more compact engine with the same structural rigidity. The clutch, alternator, and head covers are made of cast magnesium alloy.

The crankshaft is asymmetrical and mounted on differentiated main bearings to contain the weight. Engine balancing is guaranteed by the presence of two balancing countershafts (one front and one rear) mounted on ball bearings inside the crankcase and controlled by gears. The countershafts also control the water and oil pumps.

The layout of the two countershafts, placed on the side of the crankshaft, allows the first-order inertia forces to be completely balanced without introducing further unwanted forces or moments. Ducati says that thanks to this solution, the engine is capable of running at very high speeds while maintaining a vibration level comparable to a 90-degree V-twin.

The Superquadro Mono relies on two lobe pumps: a delivery pump that ensures efficient lubrication of the engine and a recovery pump (located in the connecting rod compartment) that takes the oil from the side compartments of the alternator and clutch covers in order to reduce the friction losses of the lubricant with the moving parts. This pump, together with a valve placed in the blow-by circuit, brings the crankshaft compartment under depression in order to reduce the resistance of the moving parts and to ensure effective recovery of the lubricating oil in any conditions of use of the engine.

The transmission relies on a six-speed gearbox with racing ratios derived from Ducati's experience gained with the Panigale V4. The first gear is long to allow its use in slow corners, exploiting the maximum thrust available. The clutch is in an oil bath with progressive interlocking hydraulic control, characterized by a particularly reduced lever load and specifically developed to offer easy and intuitive braking.

The gearbox can be equipped with Ducati Quick Shift (DQS) Up & Down. In this scenario, the DQS relies on a magnetic hall effect sensor and not the traditional load cell to improve accuracy and reliability.

Sourced: Ducati, Cycle World (torque values only)

Published October 2023

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