To optimize the fuel and air mixing process and improve the utilization rate of air in highlyintensified single-cylinder diesel engine, the re-entrant combustion chambers with step-typed lip and tilted lip were designed, and the influence law of throat diameter on combustion process was acquired by the experiment. By using the step-typed lip combustion chamber with a thoat diameter of 72 mm, the target of 2.6 MPa BMEP could be achieved under the excess air coefficient of 1.5~1.7, which had the characteristics of low fuel consumption, exhaust temperature and smoke and short combustion duration. The re-entrant combustion chamber with tilted lip presented lower fuel consumption, exhaust temperature and peak combustion pressure, faster heat release rate and shorter comustion duration than the counterpart with step lip under the same BMEP.
