Suzuki's research and development team has recently submitted a series of patent applications showcasing their innovative variable valve timing (VVT) system tailored explicitly for the iconic Hayabusa hyper bike. This development indicates that Suzuki is committed to extending the Hayabusa's legacy as it celebrates its 25th anniversary, aiming to enhance its performance and adapt it to comply with evolving emissions regulations.

While Suzuki's GSX-R1000 already incorporated a mechanical valve-phasing VVT system in 2017, the new patents focus exclusively on the Hayabusa, revealing a more flexible, electronically-controlled, and hydraulic method for adjusting the intake cam timing.

This advanced VVT system promises to reduce the Hayabusa's emissions and improve fuel efficiency. Simultaneously, it aims to recapture the power lost during the last overhaul, which was necessary to align the bike with Euro5 emissions standards.

The VVT system itself follows a conventional design, featuring a hydraulic cam phaser positioned between the sprocket and the intake camshaft. This phaser can subtly adjust the camshaft's position relative to the sprocket, advancing or retarding the intake valve timing.

Much like other cam-phasing VVT systems found in vehicles such as Ducati motorcycles and Kawasaki's GTR1400, this system employs engine oil pressure, controlled by an electronic solenoid, to move the camshaft in relation to the sprocket. This approach has been a staple in the automotive industry for many years.

It's important to note that while the GSX-R1000's mechanical VVT system also alters intake cam timing by rotating it relative to the sprocket, its primary focus is on enhancing performance rather than achieving a significant reduction in emissions. This is evident from the fact that the GSX-R1000 has been withdrawn from the European market due to its inability to meet Euro5 emission standards.

The GSX-R1000's system relies on metal balls situated in slightly misaligned radial channels within the cam phaser. As the camshaft spins faster, centrifugal force propels the balls outward, causing a delay in intake cam timing. At lower engine speeds, a spring restores the balls to their central position, advancing the timing.

This unique solution originated from Suzuki's now-defunct MotoGP project, as hydraulic and electronic VVT mechanisms are prohibited in MotoGP. However, this system is less versatile compared to the hydraulic kit currently in development for the Hayabusa.

With an electric actuator governing the flow of oil to the cam phaser, under the control of the bike's engine management system, the hydraulic VVT can independently advance or retard valve timing based on engine speed, aligning it with the specific requirements of emissions regulations.

For instance, the system can retard intake timing at low revs and minimal throttle input, reducing valve overlap to prevent unburned fuel from entering the exhaust. Conversely, when the throttle is opened, timing can be advanced to enhance torque, only to be later retarded at high engine RPM to prolong the intake valve opening. The electronically-controlled VVT provides endless possibilities for optimization.

While this technology is already established, especially in the automotive industry, Suzuki's patent applications are distinct in their focus on the placement of the VVT actuator and the cleverly designed oil channels connecting it to the cam phaser, minimizing any interference with other aspects of the motorcycle's design.

Suzuki Hayabusa VVT engine – what we know so far

• All about timing: The Suzuki set-up uses& an electric actuator to& divert oil pressure to& four chambers inside& the sprocket half of the& cam-phaser, each& containing vanes that& are connected to the& camshaft half of the& phaser. Direct oil to one& side of the vanes and& the timing advances,& switch the oil pressure& to the other side of the& vanes and it retards.
• Clever design keeps it neat: Seen from the front, the repositioned actuator, despite being an external addition to an existing engine rather than designed in from day one, doesn’t add any more width to the bike.
• Same bottom end: Oil channels inside the cylinder walls and the cylinder head take the oil to the cam phaser, so those parts need to be changed, but there’s an external pipe taking oil from the oil pump to the actuator, so the engine’s bottom end doesn’t need to be revised.
• No frame mods needed: Normally, the solenoid-based actuator would be mounted on the cylinder head, near the phaser, but Suzuki have shifted it down onto the side of the cylinder. That means there’s no need to modify the Hayabusa’s frame, saving lots of R&D expense.
• Reliability is built-in: Mounting the actuator lower down reduces the vibration it’s subjected to, according to Suzuki’s patents, improving its reliability. The design is also claimed to make the actuator less susceptible to damage if the bike is dropped.

#Hayabusa #Sportbike #GSXR1300