The results show that the lean quasi-homogeneous mixtures can be formed by early-injection, and the shape of combustion chamber has an obvious effect on density and temperature fields of mixture.

Quasi homogeneous charge compression ignition (QHCCI) combustion may be with low emissions, especially for soot and NO_X, according as the most fuel which is pre-mixed is lean burnt.

Under the condition of quasi-equal level condition, density distribution of homogeneous layers are conflict with the real Earth density distribution.