1. Combustion control

1.1 Thermodynamic cycle

As in any internal combustion engine, the evolution of pressure as a function of time, and therefore of cylinder volume, depends mainly on combustion kinetics and, secondarily, on heat loss through the cylinder walls. This combustion energy, often referred to as the heat release law by engine manufacturers, which results from the oxidation of the fuel by the oxygen trapped in the cylinder, is therefore particularly sensitive to the characteristics of the fuel, its diffusion in the air charge and the oxygen content of the air.

Four types of diagrams represent cycles well:

• average temperature of cylinder contents as a function of entropy (Eichelberg diagram), which highlights the heat involved...