An internal combustion engine with an exhaust gas accumulation chamber, a valve for controlling the flow of the exhaust gas into and from the exhaust gas accumulation chamber and a communicating passage for communicating the cylinder bore of the combustion chamber with the exhaust gas accumulation chamber, along which cylinder bore the piston is reciprocated. The valve is open from a first time in the compression stroke to a second time in the succeeding expansion stroke. Due to the combined operation of the valve and the movement of the piston, the exhaust gas is accumulated within the accumulation chamber only near the end of the expansion stroke and is spouted from the accumulation chamber only in the beginning of the compression stroke. The communicating passage is so arranged that the exhaust gas spouted from the accumulation chamber into the combustion chamber generates a swirl motion in the combustible gas mixture.