Stirling engine power control
AssigneeMechanical Technology Incorporated
InventorJames P. Fraser
Life of this patent
Estimating the term…
Abstract
A power control method and apparatus for a Stirling engine including a valved duct connected to the junction of the regenerator and the cooler and running to a bypass chamber connected between the heater and the cylinder. An oscillating zone of demarcation between the hot and cold portions of the working gas is established in the bypass chamber, and the engine pistons and cylinders can run cold.
Claims14
A power control for a Stirling engine having a working space including an expansion space in which heated working gas can expand to produce power, and a compression space in which working gas can be compressed, said working space comprising the volume of a gas cylinder;
- a heater, a regenerator, and a cooler connected together in series;
- gas motive means movable in said cylinder for circulating a working gas from said expansion space, through said heater, said regenerator and said cooler and into said compression space, and then back again in a cyclic flow for producing a pressure wave in the working space, and also movable in said cylinder under the influence of said pressure wave for producing power;
- said power control comprising:
- a bypass chamber for inhibiting thermal mixing of hot and cool working gas and having two ends, a first end communicating with said heater and a second end communicating with said expansion space of said cylinder;
- a gas bypass conduit connecting the junction of said expansion space of said cylinder and said bypass chamber to said compression space so as to bypass at least said heater and regenerator;
- and
- an adjustable valve in said bypass conduit for controlling the proportion of gas flowing into said expansion space of said cylinder through said bypass conduit.
In a Stirling engine having piston means movable in at least two cylinders, a first cylinder including a compression space and a second cylinder including an expansion space, for circulating a working gas through a gas flow path including a hot region which encompasses a heater and hot portions of a regenerator, and a cold region which encompasses cool portions of said regenerator and a cooler, for producing a pressure wave and for moving under the influence of said pressure wave to produce output power, a power control comprising:
- a bypass chamber having two gas flow connections, a first connected to said expansion cylinder and a second connected to said heater and further including a hot gas end, a cool gas end and a gas interface section having a temperature gradient, said bypass chamber inhibiting the thermal mixing of hot and cold gas volumes in said heater and said expansion cylinder, respectively;
- a conduit connecting said cold region of said gas flow path to said expansion cylinder;
- a valve in said conduit to vary the proportion of working gas passing through said conduit;
- whereby the amplitude of the cyclic flow through said regenerator and heater for each of all working cycles can be varied to vary the pressure amplitude in each cycle and thereby change the power output.
A method of modulating the power of a Stirling engine having a plurality of pistons disposed for reciprocation in a plurality of expansion and compression cylinders for circulating a charge of working gas through a closed gas flow path including said cylinders, a set of heat exchangers including a cooler, regenerator, and heater for each of said pistons, gas flow passages connecting in series said cylinders and said heat exchangers, and bypass means for connecting said cooler to said expansion cylinder, the method comprising:
- producing output power from said engine by producing a pressure wave in the gas flow path and moving said pistons under the influence of said pressure wave;
- bypassing a selected portion of said gas around said regenerator and said heater to reduce the output power of said engine;
- and
- causing said expansion and compression cylinders to be in a cool zone of said engine so that said pistons reciprocate in said cool zone.
Dependencies are inferred from the claim text.