Emulação do ciclo atkinson utilizando uma válvula de pistão

Abstract

The advancement of humanity presents new technological demands, no different in the automotive environment, where ever they are needed most economic engines, powerful and produce less polluting to the environment. One idea which is able to combine all of these characteristics has been proposed by Atkinson, where the cycle can provide a higher yield than the Otto cycle through an expansion stroke greater than the compression stroke. This paper presents a technology where it implements a piston controlled exhast port in place of the traditional exhaust valve, in order to obtain the Atkinson cycle from the correct synchronization of the movements. The methodology applies the new geometric relationships created by the piston controlled exhaust port so that the project proceed to a compact, efficient and advantageous compared to other models. The final result is a model that achieves a Atkinson ratio equal to 1.2, using an auxiliary piston 60 mm in diameter, 63 mm stroke and in an additional volume equal to 5.45 cm³ surface. The auxiliary cylinder is coupled in a space of 50 mm in the head and the auxiliary piston has an operating cycle which is half of the main piston cycle. This model also allows for future enhancements, it is possible to improve the diagram of the intake valves, adjust the geometry of the combustion chamber and vary the auxiliary piston stroke.