Turbocharger design

Abstract

Consulta en la Biblioteca ETSI Industriales (8115)

[EN] Nowadays, the fuel consumpt ion of combust ion engines has become a relevant issue due to the decrease of petrol reserves and the higher need of alternat ive sources. Thus, car companies in part icular are invest ing a lot of money in the research and development of dif ferent technologies which might reduce the energy consumpt ion rates of this kind of engines. There are dif ferent ways to achieve this goal. One of the systems most used at present is the one that involves the use of the residual energy avai lable in the exhaust gasses of a combust ion engine, in order to increase its power. This procedure commonly called turbocharging, is based on an increment of air pressure which increases the ai r densi ty in the engine inlet . Hence, more fuel can be injected, and more power can be achieved. I t is by this means that both the ef f iciency of the engine and the grams of fuel per kW energy are improved. With this in mind, the aim of the project is to design a turbocharger for the World Touring Car Championship (WTCC). I t is wel l known that cars in this compet it ion are 2.0L and most of them use petrol engines. SEAT uses a 2.0L diesel engine, and has lead the championship since this turbocharged car was designed. This project presents the design of a turbocharger for a BMW 320Cd in order to achieve 270 hp, power that the SEAT WTCC is able to develop and is considered needed to be compet it ive in this championship. In order to design a turbocharger, the st ress and rotor dynamics analysis has been car ried out . The main forces act ing on the shaf t of the turbocharger are the net thrust due to the turbine and compressor and the torque, which is not very high because its rotat ional speed is up to 155000 rpm. Final ly, the turbocharger designed for this project is water & oil cooled with bearings, which allows the engine to develop 270 hp. In addit ion the net thrust load is supported by the bearings, and the shaf t has been designed to support the stresses and to keep the turbocharger rotat ing far away of the dif ferent crit ical speeds that it has.