Desmodromic is a technical term used in engineering to describe a particular type of valve gear in engines. The term is pronounced /dɛzməʊˈdrɒmɪk/ (dez-moh-drom-ick) and is spelled using the English alphabet. The word is derived from the Greek words "desmos" (meaning "bond" or "link") and "dromos" (meaning "road" or "track"). Desmodromic valve gears are known for their high performance and efficiency, making them a popular choice for racing engines.
Desmodromic is an adjective that refers to a specific type of mechanical design, particularly found in engine components, that utilizes a unique valve actuation system. It is derived from the combination of the Greek words "desmos" meaning "link" and "dromos" meaning "course" or "path."
In the context of engines, desmodromic systems are characterized by their use of mechanically operated valves instead of relying on more common methods such as springs or air pressure. This design ensures precise control over the motion of the valves, enabling the engine to achieve higher revolutions per minute (RPM) and ultimately deliver greater power output.
The core principle behind desmodromic systems is the use of both an opening cam and a closing cam to actuate the valves, each with its own dedicated lobe. This eliminates the need for springs to close the valves, and instead relies on direct mechanical linkages to facilitate both opening and closing actions. By mechanically controlling the valve motion in this manner, desmodromic systems can avoid common issues encountered with traditional valve actuation systems, such as valve float or inadequate valve control at high RPMs.
Most commonly associated with high-performance engines and racing vehicles, the use of desmodromic technology has been primarily exemplified by certain manufacturers in the automotive and motorcycle industry. It is regarded as a sophisticated valve actuation system that offers improved engine performance, responsiveness, and reliability.
The word "desmodromic" is derived from two Greek roots: "desmo" meaning "bond" or "ligament", and "dromos" meaning "track" or "way". The term was first used in the context of racing engines, specifically in reference to the desmodromic valve system. This system replaces the traditional valve spring mechanism with a direct linkage that opens and closes the valves. The linkage consists of interlocking components that create a positive control over the valve's movement. This precise and efficient mechanism is what led to the term "desmodromic" being coined.