Cycle-to-cycle transient model of 4-stroke combustion engines

In 4-stroke combustion engines, managing the cycle-to-cycle transient characteristics of the mass of the air, the fuel and the burnt gas is an important issue due to the cycle-to-cycle coupling caused by the imbalance of cyclic combustion. This paper presents a discrete-time model that represents the cycle-to-cycle transient behavior of in-cylinder state variables under the assumption of measurability of the total gas mass and the residual gas fraction. It is shown that if the state variables are chosen as total fuel mass, residual unburnt air and the burnt gas mass, then the system is modeled as a time-varying linear system. Validation results is demonstrated which conducted on a full-scaled gasoline engine test bench.