Generation of electricity from exhaust gas

摘要

A turbo-generator system generates electricity from the exhaust gas of an internal combustion engine 1. The electric current generated by the generator 11 (e.g. a switched reluctance machine) is controlled so as to maintain the turbine 3 at a first pre-set rotational speed. The amount of electric current demanded from the generator 11 is limited or reduced if the electrical system 17 cannot accept a greater electric current or if the exhaust gas pressure upstream of the turbine 3 is too great. In such cases, the proportion of the exhaust gas permitted to bypass the turbine 3 is controlled so as to maintain the turbine 3 at a second pre-set rotational speed that is slightly greater than the first. The turbine's preset speeds are chosen to maximise electrical generating efficiency and for turbine safety. The system maximises the amount of electricity generated, avoids excessive exhaust gas back-pressure on the engine 1, and avoids overloading the electrical system 17.