Conclusion on energy analysis
Analysis of energy transfer in automotive engines

The energy losses encountered in a combustion engine can be approached in different ways (figure 14 ). From a thermodynamic point of view, the main losses are convective and radiative exchanges between the gases and the chamber walls, and the thermal residue in the exhaust gases. Between them, these losses account for up to 60% of the injected power, leading to an efficiency of around 40%.

On a broader scale, the indicated power is not entirely reflected in useful mechanical power. The mechanical architectures used cannot totally cancel out friction losses, which account for 10% of the indicated mechanical power (or 4% of fuel power). What's...