Utveckling av kyl- och smörjsystem för ekobilen Agilis HCCI motor
Every year, KTH participates in the Shell Eco Marathon, a competition whose goal is to design a vehicle that can go as far as possible using only the equivalent energy of one liter of petrol fuel. This year, one of KTH?s contributions to this race is the Agilis prototype; a car powered by a uniquely configured HCCI-engine developed at the university. The engine is dependent of several subsystems in order to work properly, among other, systems for cooling and lubrication.Combustion engines are in need of a cooling system that reduces the heat developed during the combustion. In general, two main types of cooling systems are employed; either air cooling, where the outside of the cylinder is exposed to a flow of the surrounding air, ore water cooling, where water flows in tubes around the engine, and the heat are transferred by the water to the surrounding air through a heat exchanger.The purpose of the lubrication system is to prevent the friction that builds up in the interference between moving parts in the engine. Several principles of lubricating the engine are used today. Bigger engines are commonly lubricated by forcing lubricants through pipes, exposing them to the moving parts. A simpler system is keeping the lubricant inside the crankcase, letting the rapid motion of the crankshaft make the lubricant splash around and on to the moving parts of the engine.An HCCI-engine can be described as a combination of a petrol and diesel engine. In resemblance to the diesel engine, the ignition is created by compression. It has the same efficiency and emission levels as a diesel.Water cooling and splash lubrication are employed in the Agilis engine. These systems are assembled of existing components rather than crafted especially for this application, due to limitations in time and resources for production. Mounts and transmission for powering the pumps and other components have been manufactured.For further improvement-work, it is recommended to design as many of the included components as possible. The reason being the possibility to achieve higher efficiency with a system made up of exclusively custom made parts.