Hybrid gas turbine engine and flywheel propulsion system

• US 4,414,805 A
• Filed: 11/27/1981
• Issued: 11/15/1983
• Est. Priority Date: 11/27/1981
• Status: Expired due to Fees

• Current Assignee: General Motors Corporation (Motors Liquidation Co. GUC Trust)
• Original Assignee: General Motors Corporation (Motors Liquidation Co. GUC Trust)
• Inventors: Walker, Frank H.
• Primary Examiner(s): Casaregola, Louis J.
• Assistant Examiner(s): Stout, Donald E.
• Application Number:
  US06/325,335
• Time in Patent Office: 718 Days
• Field of Search: 60/39.04, 60/39.161, 60/39.27, 60/39.41, 60/39.5, 60/39.43, 60/39.163
• US Class Current: 60/792
• CPC Class Codes: F02C 3/10 with another turbine driving an output shaft but not driving the compressor
• CPC Class Codes: F02C 6/006 Open cycle gas-turbine in which the working fluid is expanded to a pressure below the atmospheric pressure and then compressed to atmospheric pressure
• CPC Class Codes: F02C 7/36 Power transmission arrangements between the different shafts of the gas turbine plant, or between the gas-turbine plant and the power user F02C3/107 - F02C3/13 and F02C7/32 take precedence; couplings for transmitting rotation F16D; gearing in general F16H
• CPC Class Codes: F02C 9/56 with power transmission control
• CPC Class Codes: Y02T 50/60 Efficient propulsion technologies, e.g. for aircraft

Abstract

A hybrid propulsion system particularly for automotive application including a subambient pressure cycle gas turbine engine having a primary turbine-compressor rotor assembly connected to a load shaft and a secondary turbine-compressor rotor assembly gas coupled with the primary rotor assembly, a flywheel rotatable with the secondary rotor assembly, and variable geometry nozzles at the turbines operative during engine operation at a steady state power output level to effect partial motive fluid expansion at the primary turbine to drive the load and the primary compressor and partial motive fluid expansion at the secondary turbine to drive the secondary compressor which maintains subambient pressure and during engine operation at a peak power output level to effect substantially total motive fluid expansion across only the primary turbine for increased power at the load shaft, the flywheel being operative during peak power level operation to drive the secondary compressor to maintain total motive fluid expansion to subambient pressure.

Claims

1. In combination with a subambient pressure cycle gas turbine engine having a peak power output level and a steady state power output level substantially less than said peak power output level and including a load shaft, a combustor, a primary compressor, a primary turbine drivingly connected to said primary compressor and to said load shaft, a secondary compressor, a secondary turbine drivingly connected to said secondary compressor, and duct means serially connecting said pimary compressor and said combustor and said primary turbine and said secodary turbine and said secondary compressor so that motive fluid generated in said combustor from combustion of fuel in air pressurized by said primary compressor may expand through respective ones of said primary and said secondary turbines to a subambient pressure level maintained by said secondary compressor and thereafter be compressed by the latter to ambient pressure, the combination comprising, a flywheel drivingly connected to said secondary compressor, and motive fluid expansion control means at said primary turbine and at said secondary turbine operative during engine operation at said steady state power output level to serially effect partial expansion of said motive fluid at said primary turbine whereby said steady state power output level is achieved at said load shaft and partial expansion at said secondary turbine whereby sufficient energy is extracted and directed to said secondary compressor to maintain said subambient pressure level and further operative during engine operation at said peak power output level to effect a substantially total expansion of said motive fluid at said primary turbine so that said peak power output level is achieved at said load shaft, said flywheel being operative to drive said secondary compressor during engine operation at said peak power output level thereby to maintain said subambient pressure level for said total motive fluid expansion.

2. The combination recited in claim 1 wherein said motive fluid expansion control means includes variable geometry means at said primary turbine and at said secondary turbine.

3. The combination recited in claim 1 wherein each of said primary and said secondry turbines is a radial flow turbine and each of said primary and said secondary compressors is a radial flow compressor.

4. A hybrid gas turbine engine and flywheel propulsion system comprising;

a subambient pressure cycle gas turbine engine having a peak power output level and a steady state power output level substantially less than said peak power output level and including a load shaft, a combustor, a first rotatable monorotor defining a primary radial flow compressor and a primary radial flow turbine, means drivingly connecting said first monorotor to said load shaft, a second rotatable monorotor defining a secondary radial flow turbine and a secondary radial flow compressor, and duct means serially connecting said primary compressor and said combustor and said primary turbine and said secondary turbine and said secondary compressor so that motive fluid generated in said combustor from combustion of fuel in air pressurized by said primary compressor may expand through respective ones of said primary and said secondary turbines to a subambient pressure level maintained by said secondary compressor and thereafter be compressed by the latter to ambient pressure;

a recuperator operative to effect heat exchange between said motive fluid after expansion through said secondary turbine and said pressurized air prior to combustion;

a heat exchanger operative to effect heat exchange between ambient air and said motive fluid after heat exchange in said recuperator;

a flywheel rigidly connected to said second monorotor; and

motive fluid expansion control means at said primary turbine and at said secondary turbine operative during engine operation at said steady state power output level to effect partial expansion of said motive fluid at said primary turbine whereby said steady state power output level is achieved at said load shaft and partial expansion at said seconday turbine whereby sufficient energy is extracted and directed to said secondary compressor to maintain said subambient pressure level and further operative during engine operation at said peak power output level to effect a substantially total expansion of said motive fluid at said primary turbine so that said peak power output level is achieved at said load shaft, said flywheel being operative to drive said secondary compressor during engine operation at said peak power output level thereby to maintain said subambient pressure level for said total motive fluid expansion.

5. A hybrid gas turbine engine and flywheel propulsion system comprising;

a subambient pressure cycle gas turbine engine having a peak power output level and a steady state power output level substantially less than said peak power output level and including a combustor, a load shaft connected to a load capable of back driving said load shaft through load inertia, a first monorotor defining a primary radial flow compressor and a primary radial flow turbine and supported on said engine for rotation at a first monorotor normal speed corresponding to engine operation at said steady state power output level and a first monorotor higher speed corresponding to engine operation at said peak power output level, means drivingly connecting said first monorotor to said load shaft, a second monorotor rotatably supported on said engine and defining a secondary radial flow turbine and a secondary radial flow compressor, and duct means serially connecting said primary compressor and said combustor and said primary turbine and said secondary turbine and said secondary compressor so that motive fluid generated in said combustor from combustion of fuel in air pressurized by said primary compressor may expand through respective ones of said primary and said secondary turbines to a subambient pressure level maintained by said secondary compressor and thereafter be compressed by the latter to ambient pressure;

a recuperator operative to effect heat exchange between said motive fluid after expansion through said secondary turbine and said pressurized air prior to combustion;

a heat exchanger operative to effect heat exchange between ambient air and said motive fluid after heat exchange in said recuperator;

a flywheel rigidly connected to said second monorotor and rotatable therewith;

first variable geometry motive fluid expansion control means at each of said primary turbine and said secondary turbine operative during engine operation at said steady state power output level to effect partial expansion of said motive fluid at said primary turbine whereby said steady state power output level is achieved at said load shaft and partial expansion at said secondary turbine whereby energy is extracted and directed to said secondary compressor to maintain said subambient pressure level and further operative during engine operation at said peak power output level to effect substantially total expansion of said motive fluid at said primary turbine so that said peak power output level is achieved at said load shaft, said flywheel being operative to drive said secondary compressor during engine operation at said peak power output level thereby to maintain said subambient pressure level for said total motive fluid expansion; and

second control means at said combustor and at each of said first and said second monorotors operative when substantially no engine power is demanded and said load shaft back drives said first monorotor to reduce the level of combustion in said combustor and to expand air compressed in said primary compressor through said secondary turbine to increase the speed of said second monorotor and said flywheel to a maximum second monorotor speed so that load kinetic energy is transferred to and stored in said second monorotor and then operative to mechanically accelerate said first monorotor to said first monorotor higher speed to thereby transfer to and store additional load kinetic energy in said first monorotor.