Implementation of an exhaust system for an opposed piston two stroke HCCI engine

Abstract

Consulta en la Biblioteca ETSI Industriales (8534)

[EN] The aim of this thesis is the improvement of the operation of an opposed piston two stroke engine with HCCI-combustion. The main focus is the charge exchange process, concretely the exhaust process. The engine has been studied from the perspective of the two stroke Otto cycle. Charge exchange process in two stroke engines is characterized by the need of expelling the burnt gases and introducing the fresh mix each expansion stroke, and the absence of valves. Control of the gas flow through the cylinder motivates two of the most characteristic systems on two-stroke engines: scavenging compressor and exhaust pipe. The design and implementation of these two systems has needed the development of several tasks: port timing has been characterized; a compressed air intake installation has been built in order to be able to modify the inlet air conditions; different injection systems have been tested as well. Finally, an exhaust pipe has been installed and tuned. With this aim, a logical approach to the problem has been done: ¿ The behavior of compressible gas flow through ducts has been studied. ¿ The influence of the dimensions of the exhaust pipe has been understood by doing a design. ¿ The experimental observation of the pressure pulse propagation through the exhaust flow has allowed the exhaust pipe tuning.