Desmodromic valves, as used by Ducati motorcycles, are indeed a unique and distinctive feature of their engines. While other motorcycle and automobile manufacturers have experimented with desmodromic valve systems in the past, Ducati has been the most prominent and consistent proponent of this technology.
The primary advantage of desmodromic valves is the elimination of valve float, which occurs when the valves are unable to close properly at high engine speeds. In a traditional valve system, springs are used to close the valves, and at high RPMs, the springs may not be able to keep up with the valve motion, leading to a loss of power and potential engine damage. The desmodromic system, on the other hand, uses dedicated cams to both open and close the valves, ensuring precise control and eliminating the possibility of valve float.
They require additional components such as extra cams, rocker arms, and actuators, which increase manufacturing complexity and cost. This complexity can also make maintenance and repairs more challenging and expensive.
Weight and Packaging: Desmodromic valve systems tend to be heavier than traditional systems due to the additional components involved. In motorsports and high-performance applications, weight reduction is crucial, and manufacturers often prioritize lightweight designs. Additionally, the larger size and increased complexity of desmodromic systems can pose challenges in terms of engine packaging and overall design.
Advancements in Valve Spring Technology: Over the years, significant advancements have been made in valve spring technology, allowing traditional spring-operated systems to handle high RPMs more effectively. Advanced materials and design techniques have improved spring reliability and reduced the likelihood of valve float, narrowing the performance gap between traditional valve systems and desmodromic systems.
Performance Trade-offs: While desmodromic valves offer advantages in terms of precise valve control, they also introduce certain trade-offs. The increased friction and wear associated with the sliding action of the desmodromic components can affect overall engine efficiency and longevity. Manufacturers must carefully balance the benefits of the desmodromic system with the potential drawbacks in terms of performance, emissions, and durability.
Considering these factors, motor companies evaluate various trade-offs when selecting valve systems for their engines. While desmodromic valves have proven successful for Ducati in their niche market of high-performance motorcycles, other manufacturers have opted for alternative solutions that meet their specific requirements while balancing factors such as cost, weight, packaging, and overall engine performance.