TY - JOUR

T1 - Mixture formation and controlled auto-ignition combustion in four-stroke gasoline engines with port and direct fuel injections

AU - Cao, Li

AU - Zhao, Hua

AU - Jiang, Xi

AU - Kalian, Navin

PY - 2005/8

Y1 - 2005/8

N2 - Controlled auto-ignition (CAI) combustion, also known as homogeneous charge compression ignition (HCCI) can be achieved by trapping residuals with early exhaust valve closure in both port and direct fuel injection four-stroke gasoline engines. A multi-cycle three-dimensional engine simulation program has been developed and applied to study the effect of injection on in-cylinder mixing and CAI combustion. The full engine cycle simulation, including complete gas exchange and combustion processes, was carried out over several cycles in order to obtain the stable cycle for analysis. The combustion models used in the present study are based on the Shell auto-ignition model and the characteristic-time combustion model, both of which have been modified to take the high level of residual gas into consideration. A liquid sheet break-up spray model was used for the droplet break-up processes. The analyses show that the injection timing plays an important role in affecting the in-cylinder air/fuel mixing and mixture temperature, which in turn affects the CAI combustion and engine performance. In comparison with the port fuel injection case, an early direct injection at exhaust valve closure can lead to higher load and lower fuel consumption.

AB - Controlled auto-ignition (CAI) combustion, also known as homogeneous charge compression ignition (HCCI) can be achieved by trapping residuals with early exhaust valve closure in both port and direct fuel injection four-stroke gasoline engines. A multi-cycle three-dimensional engine simulation program has been developed and applied to study the effect of injection on in-cylinder mixing and CAI combustion. The full engine cycle simulation, including complete gas exchange and combustion processes, was carried out over several cycles in order to obtain the stable cycle for analysis. The combustion models used in the present study are based on the Shell auto-ignition model and the characteristic-time combustion model, both of which have been modified to take the high level of residual gas into consideration. A liquid sheet break-up spray model was used for the droplet break-up processes. The analyses show that the injection timing plays an important role in affecting the in-cylinder air/fuel mixing and mixture temperature, which in turn affects the CAI combustion and engine performance. In comparison with the port fuel injection case, an early direct injection at exhaust valve closure can lead to higher load and lower fuel consumption.

KW - controlled auto-ignition (CAI)

KW - homogeneous charge compression ignition (HCCI)

KW - port fuel injection (PFI)

KW - gasoline direct injection (GDI)

KW - injection timing

U2 - 10.1243/146808705X30611

DO - 10.1243/146808705X30611

M3 - Journal article

VL - 6

SP - 311

EP - 329

JO - International Journal of Engine Research

JF - International Journal of Engine Research

SN - 2041-3149

IS - 4

ER -