Abstract: In an internal combustion engine, for the operation at part-load, a heat exchanger collects heat from the exhaust gas and re-injects the collected heat into the intake gas being at an intermediate stage (p3c) of the compression. The exhaust gases are cooled down from point Q81c to point Q61c. The intake gases are heated up from point Q33c to point Q43c. The average combustion temperature is higher while the exhaust gas temperature is lowered, wherefore the yield is definitely increased.