A control-oriented combustion model for a turbulent jet ignition engine using liquid fuel

Abstract

A control-oriented engine model is necessary for developing and validating the associated engine control strategies. For engines equipped with the turbulent jet ignition system, the interaction between the pre-and main-combustion chambers should be considered in the control-oriented model for model-based control strategies that optimize the overall thermal efficiency in real-time. Therefore, a two-zone combustion model based on the newly proposed parametervarying Wiebe function is proposed. Since the engine uses the liquid fuel, a pre-chamber air-fuel mixing and vaporization model are also developed. The model was validated using the experimental data from a single-cylinder turbulent jet ignition engine under different operational conditions, and the simulation results show a good agreement with the experimental data. The relative simulation error of the in-cylinder pressure is less than 8%. For most of the other pressure-related variables, such as indicated mean effective pressure and main-chamber burn duration, the relative errors are within 5%.

Experiments and modeling of a dual-mode, turbulent jet ignition engine

“…The burn dependency between pre- and main-combustion chambers was adapted from the already developed and tested concept of a parameter-varying Wiebe function 3,17 with a number of readjustments. Song et al 3,17 reported a high correlation between the mass flow rate of the turbulent jets and the rate of combustion in the main chamber. Thus, they linked the intensity of the turbulent jets to their combined mass flow rate.…”

“…In these equations, m · tur is the mass flow rate of turbulent jets; C p is the specific heat at constant pressure; T tur is the temperature of turbulent jets; E · tur is the rate of energy of turbulent jets; θ Spark is the crank angle degree at the time of spark timing; θ is the instantaneous crank angle degree; E · tur + is the filtered energy term to consider the effect of turbulent jets after spark timing and before top dead center of fire (TDCF) (0 CAD), while the flow direction is from pre- to the main-combustion chamber; β is a calibrating parameter to maintain the burn dependency of the pre- to the main-combustion chamber; b is the mathematical expression for the intensity of turbulent jets; 3,17 θ 0 , Main is the main chamber SOC which is calculated as ...…”

“…Pre-chamber evaporation was compensated with a two-step fuel injection event. Burn dependency between pre- and main-combustion chambers was also adapted from a previously developed and tested concept of a parameter-varying Wiebe function 3,17 with a number of readjustments. The engine system model developed was calibrated based on experimental data from the Prototype II DM-TJI engine.…”

“…The engine pre-chamber was equipped with a separate fuel injector, while the air delivery to the pre-chamber was provided through a high-pressure direct injection (DI) fuel injector. Engine specifications can be found in the work done by Vedula et al 2 Song et al 17 developed a control-oriented combustion model calibrated based on experimental data from the Prototype I DM-TJI engine. This study was a continuation of work published by Song et al 3 on a control-oriented model of a TJI system in a rapid compression machine.…”

“…This study was a continuation of work published by Song et al 3 on a control-oriented model of a TJI system in a rapid compression machine. Song and colleagues later expanded the work done in their study of 2017 17 to a state-space model for a gasoline-powered TJI engine. 18 The former 18 was also calibrated based on experimental data from the Prototype I DM-TJI engine at MSU.…”