The 65° V4 engine: The state of the art in superbike engine technology
For years, Aprilia has known that the narrow V configuration is the ideal engine solution for maximum performance, mass centralisation and dynamic bike balance. Used in the past for the marque's sports twins and revived for the RSV4 Superbike project, this engine architecture immediately proved to be competitive on the track.
The 65° V4 engine in the Aprilia RSV4 R is very closely related to the powerplant which, with Max Biaggi at the helm, has proven to be mind-bendingly quick on the track. An engine delivering incredible performance which also allows a remarkable degree of freedom in the design of the chassis. Thanks to this engine, the chassis engineers have been able to create a superlative chassis architecture worthy of the reputation of Aprilia's finest hypersports machines.
In addition to the engineering exclusiveness of a configuration that is without par anywhere in the world, the technical advantages of Aprilia's 65° V4 are:
- The engine sits perfectly within the frame for optimised mass centralisation
- The possibility of creating an ideal chassis layout, with the pinion shifted far forward and a long swingarm
- Absolute slimness; with overall width comparable to that of a twin cylinder bike
- Minimised frontal area, translating to huge benefits in terms of aerodynamic efficiency
- The possibility of very large bores; the slimness of the engine means that the engineers can define very oversquare combustion chamber layouts, increasing the valve diameter and improving efficiency
- Optimum fluid dynamics with an angle between cylinders greater than the industry standard of 60°, leaving more space for straight intake ducts.
The engine was entirely developed by Aprilia's in-house R&D division, a centre of technological excellence and one of the most advanced facilities of its kind in Europe, which benefits from the invaluable support of the highly successful Aprilia Race Division. The goal of the engineers was not just to achieve class beating performance but also to make the engine much more usable than any of its rivals, because horsepower alone means nothing if the rider cannot make full use of every last ounce of power. The narrow V architecture has resulted in an engine that is incredibly compact in length, offering advantages in terms of mass centralisation and minimising the inertia ellipse, which in turn made it possible to define an extremely high performance chassis.
The innovative timing system (with the chain driving only the intake camshaft, which in turn drives the exhaust camshaft via a gear) has made extremely compact heads (just 250 mm at the rear of the engine) especially in the area beneath the frame spars, which are thus much narrower than would otherwise be possible.
A countershaft dampens first and second order vibrations, making the engine even smoother than a 90° V twin.
The monobloc crankcase with integrated cylinder liners ensures maximum rigidity and consistent performance.
State of the art electronics
The electronic management system is another example of the V4 engine's technological supremacy. Full Ride-by-Wire technology eliminates any direct connection between the throttle grip and the throttle valves, which are entirely controlled by a latest Marelli control unit that also controls the ignition and the 8 injectors (the 4 secondary fan pattern injectors come into play at high loads).
Each bank has a dedicated servo unit actuating its own two throttle bodies only. This means that the aperture of the four throttle valves and, as a consequence, the quantity of fuel injected, can be controlled independently. This solution, applied here for the first time ever in a production bike, opens up practically infinite possibilities for power delivery control. This technology offers immediately tangible benefits to the rider, with triple mapping (adjusting power delivery and maximum power) selectable directly from the handlebar allowing the character of the bike to be modified to suit the rider's personal riding style or the track conditions at any time.
- T - TRACK: no-compromise performance for track use
Unleashes the full 180 bhp of fury at the slightest twist of the grip. Recommended for expert riders in ideal track and weather conditions;
- S-SPORT: for exciting road use
Smooth power delivery. Torque limited in the first 3 gears for greater control. For an exciting but less challenging ride;
- R - ROAD: Total usability in all conditions
Power reined in to 140 HP in all gears. Greater usability in all conditions.
A butterfly valve in the exhaust optimises power delivery.
The transmission has also been designed to the meet most advanced criteria to offer the maximum performance possible. To underscore the racing soul of the V4 engine, it is mated to a cassette gearbox with a wet sump lubrication system (with oil in the crankcase). The wet clutch features a mechanical slipper system for optimised engine braking torque control and stability under hard braking.
THE 65° V4 ENGINE in short
monobloc with integrated cylinder liners
4 valves per cylinder (Titanium and Nymonic) operated directly by a camshaft driven by a mixed chain/gear system, lateral timing chain, central gear train.
electronic injection with 2 injectors per cylinder and integrated independent Ride by Wire system for each bank. Three mappings selectable from handlebar.
six speed cassette gearbox
Multiplate wet clutch with slipper system
Magneti Marelli control unit managing ignition, injection and Ride by Wire system.