Utveckling av 2²

Sammanfattning

Environment friendly transports are one of the main topics in the industry and society today.

Shell organizes an annual university competition called Shell Eco Marathon. The goal is to build

the car that consumes the least fuel during a race. KTH participated for the first time in 2006.

The engine for this competition, DoubleTwo, has been developed within the school. The

principle is a two stroke counter piston HCCI engine with variable compression ratio. HCCI

stands for homogenous charge compression ignition. The combustion is quick and simultaneous

which leaves a high efficiency and naturally low emissions of NO

xand soot. The compression

ignition timing is instable which is the reason for using variable compression ratio. The

mechanical system for changing compression ratio is now patent protected.

So far the principle has been verified, but lots of tests remain. The indicated efficiency is 32,5 %

at a 6500 rpm and I

MEP(Indicated mean effective pressure) is 4 bar.

The project will be continued by other students and therefore this report is focusing on the

different systems around the engine and the function of the engine rather than engine tests.