Turbocharger

A turbocharger is a centrifugal compressor driven by a turbine wheel in the exhaust gas stream, used to force a greater mass of air into diesel engine cylinders than the piston can induct naturally. This process, known as pressure charging, raises mean effective pressure, increases power output, and improves fuel efficiency. On large two-stroke engines the turbocharger typically operates in conjunction with an auxiliary blower that maintains scavenge air pressure during slow running and manoeuvring when exhaust energy is insufficient to drive the turbine alone. Maintenance of turbochargers is prescribed in the maker's instruction manual and is subject to planned maintenance system records reviewed during classification surveys. Engineers carry out routine water washing of the turbine side and dry grit cleaning of the compressor side at sea, and record blower speeds, exhaust temperatures, and boost pressure in the engine log. A sudden drop in boost pressure or rise in exhaust temperatures can indicate compressor fouling, turbine damage, or the onset of surge — all of which must be investigated promptly to prevent loss of propulsion or engine damage.