Millerzyklus

The Millerzyklus, known in English as the Miller cycle, is a type of thermodynamic cycle used in internal combustion engines to improve efficiency. It was developed by Ralph Miller in the 1940s as an alternative to traditional Otto cycle engines. The primary feature of the Miller cycle is the modification of the intake and compression processes to reduce the work required during compression without sacrificing power output, thus increasing overall efficiency.

In a typical Miller cycle engine, the intake valve remains open during part of the compression stroke, resulting in a lower effective compression ratio compared to the expansion ratio. This process is achieved through either a delayed intake valve closure (also called the delayed intake cycle) or by employing a supercharger to compensate for the reduced trapped volume. The cycle generally involves a high expansion ratio and a lower compression ratio, which minimizes thermal losses and improves fuel efficiency.

The advantages of the Miller cycle include higher thermal efficiency, better fuel economy, and lower emissions. However, its implementation often requires additional components such as superchargers or turbochargers to maintain power levels, which can increase complexity and cost.

The Miller cycle is utilized in various modern engines, particularly in hybrid vehicles and some high-efficiency gasoline engines, where improved fuel consumption and reduced emissions are prioritized. It is considered a promising technology for achieving more sustainable and efficient internal combustion engine performance in the context of evolving automotive standards.