Compound engine system with rotary engine
AssigneePratt & Whitney Canada Corp.
InventorAndré Julien
Life of this patent
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Abstract
A compound engine system comprising a rotary engine having a volumetric compression ratio lower than its volumetric expansion ratio, and a recess defined in the peripheral wall of the rotor in each of the chambers having a volume of more than 5% of the displacement volume of the chamber. The expansion in the turbine section compensates for the relatively low expansion ratio of the rotary engine.
Claims19
A compound engine system comprising:
- a rotary engine having a stator body having walls defining an internal cavity, and a rotor body mounted for eccentric revolutions within the cavity, peripheral walls of the rotor and stator bodies cooperating to provide rotating chambers of variable volume when the rotor body moves relative to the stator body, the volume of each chamber varying between a minimum volume and a maximum volume with a difference between the maximum and minimum volumes defining a displacement volume, the peripheral wall of the rotor body having a recess defined therein in each of the chambers, a volume of each recess being more than 5% of the displacement volume, the rotary engine having at least one inlet port and at least one exhaust port in successive communication with each of the chambers;
- a compressor section communicating with the at least one inlet port;
- and
- a turbine section connected to the at least one exhaust port.
A method of improving combustion stability of a compound engine system including at least one rotary engine having rotating chambers each having a volume varying between a minimum volume and a maximum volume, the method comprising:
- positioning inlet and outlet ports of the rotary engine such that the rotary engine has a volumetric compression ratio lower than a volumetric expansion ratio thereof;
- and
- for each of the rotating chambers, shaping a respective recess in a rotor of the rotary engine to form part of the chamber, the respective recess being shaped with a volume corresponding to more than 5% of a displacement volume of the chamber, wherein the displacement volume corresponds to a difference between the maximum and minimum volumes of the chamber.
Dependencies are inferred from the claim text.