An electric turbo-compound (ETC) system is defined where a turbine coupled to a generator (

turbogenerator A turbo generator is an electric generator connected to the shaft of a steam turbine or gas turbine for the generation of electric power. Large steam-powered turbo generators provide the majority of the world's electricity and are also used b ...

) is located in the

exhaust gas Exhaust gas or flue gas is emitted as a result of the combustion of fuels such as natural gas, gasoline (petrol), diesel fuel, fuel oil, biodiesel blends, or coal. According to the type of engine, it is discharged into the atmosphere through a ...

flow of a reciprocating engine to harvest waste heat energy and convert it into electrical power. An example of an ETC system is where a turbogenerator is located downstream of a

turbocharger In an internal combustion engine, a turbocharger (often called a turbo) is a forced induction device that is powered by the flow of exhaust gases. It uses this energy to compress the intake gas, forcing more air into the engine in order to pr ...

turbine of an

internal combustion engine An internal combustion engine (ICE or IC engine) is a heat engine in which the combustion of a fuel occurs with an oxidizer (usually air) in a combustion chamber that is an integral part of the working fluid flow circuit. In an internal co ...

(ICE). The power generated from the ETC system can be used to feed into an electrical grid or provide power to local electrical loads such as engine auxiliaries. ETC systems are commercially available for stationary power gensets and at an advanced stage of development for automotive applications to improve the

fuel efficiency Fuel efficiency is a form of thermal efficiency, meaning the ratio of effort to result of a process that converts chemical potential energy contained in a carrier (fuel) into kinetic energy or work. Overall fuel efficiency may vary per device, ...

of gas and diesel engines by recovering waste energy from the exhaust gases. The ETC system is typically located downstream of the turbocharger of an ICE. The exhaust gases expand first through the turbocharger turbine and then through the ETC turbine, which drives a high-speed

alternator An alternator is an electrical generator that converts mechanical energy to electrical energy in the form of alternating current. For reasons of cost and simplicity, most alternators use a rotating magnetic field with a stationary armature.G ...

generating DC or AC power. In gensets, this extra power is added to the power output from the primary generator, increasing the system efficiency. For automotive application the ETC would become the primary generator used to power the vehicle’s auxiliary systems.

References

{{Reflist Turbines