AIRCRAFT PROPULSION SYSTEMS : A DIESEL HYBRID ENGINE

Document Type : Original Article

Authors

1 Graduate student, Dpt. of Mechanical Engineering, Bologna University, Forlì, Italy.

2 Professor, Dpt. of Mechanical Engineering, Bologna University, Forlì, Italy.

Abstract

ABSTRACT
Recent developments in diesel piston engine technology have increased performance
in a very significant way. In this paper a new hybrid diesel-turbine engine is introduced
and it is compared to up-to-date turboprops. The weak point of the common rail engine
is the difficulty to obtain very fast injectors for large engines. Automotive injectors are
available only for small power outputs. The problem was solved with a dual chambers
piston with two injectors per cylinder. It is then possible to use off-the-shelf automotive
common rail components even on very large diesel engines with benefits on
combustion especially at medium low power level. The other more interesting
advantage is a significant increase on crankshaft maximum speed and reduction of
head mechanical stress. It is then possible to have smaller and more powerful
turbodiesel and hybrid engines. Another advantage is the improved reliability of a dual
injection system. The diesel – turbine hybrid power unit proposed in this paper
combines the advantages of the turboprop/turbofan/turboshaft and piston turbo-dieselprop
/ turbo-diesel-fan / turbodiesel engines. However, It should be clear than the
automotive commercial common rail components should be treated to use jp4, jp8 and
jet(A1) fuels and to fulfil aeronautical requirements.

Keywords