The present invention concerns an external heat source engine comprising: —at least one cylinder (2), —a piston (3) that is movable back and forth in the cylinder, —a cylinder head (4) defining a working chamber (5) with the piston and the cylinder, —a heat exchanger (6) for exchanging heat between a working gas and a heat-transfer fluid, —a distribution comprising two rotary slide valves (20, 30) mounted so as to be able to rotate in the cylinder head and bringing the working chamber selectively into communication with the following resources: •a working gas inlet (A), •a cold end (B) of the exchanger, •a hot end (C) of the exchanger, •an exhaust (D). The slide valves (20, 30) comprise internal passages that open through the side wall of same through at least one opening that communicates selectively with the working chamber (5) via at least one opening formed in the cylinder head (4).

The present invention concerns an external heat source engine comprising: at least one cylinder (2), a piston (3) that is movable back and forth in the cylinder, a cylinder head (4) defining a working chamber (5) with the piston and the cylinder, a heat exchanger (6) for exchanging heat between a working gas and a heat-transfer fluid, a distribution comprising two rotary slide valves (20, 30) mounted so as to be able to rotate in the cylinder head and bringing the working chamber selectively into communication with the following resources: a working gas inlet (A), a cold end (B) of the exchanger, a hot end (C) of the exchanger, an exhaust (D). The slide valves (20, 30) comprise internal passages that open through the side wall of same through at least one opening that communicates selectively with the working chamber (5) via at least one opening formed in the cylinder head (4).

An efficient stirling engine comprises an expansion chamber with a heater and a compression chamber with a cooler, wherein the two chambers are connected through a regenerator. A passage between the heater and the expansion chamber is provided with a first valve system, a passage between the cooler and the compression chamber is provided with a second valve system, the first valve system can close or open the passage between the heater and the expansion chamber, and the second valve system can close or open the passage between the cooler and the compression chamber. After adopting the structure above, when a heating end is heated to expand, a cooling end at the other end is closed, and on the contrary, when the cooling end is cooled to shrink, the heating end at the other end is closed, so that the heating energy is fully used, so as to increase the efficiency of the stirling engine.

An efficient stirling engine comprises an expansion chamber with a heater and a compression chamber with a cooler, wherein the two chambers are connected through a regenerator. A passage between the heater and the expansion chamber is provided with a first valve system, a passage between the cooler and the compression chamber is provided with a second valve system, the first valve system can close or open the passage between the heater and the expansion chamber, and the second valve system can close or open the passage between the cooler and the compression chamber. After adopting the structure above, when a heating end is heated to expand, a cooling end at the other end is closed, and on the contrary, when the cooling end is cooled to shrink, the heating end at the other end is closed, so that the heating energy is fully used, so as to increase the efficiency of the stirling engine.