高效增压直喷氢内燃机近零 NO_x 排放试验优化

Thermal efficiency and near-zero NO_x emission(NO_x＜20×10^-6)were experimentally optimized on a 2.0 L turbocharged direct injection hydrogen engine with lean combustion. The experiments were carried out at large load and speed operating range with different injection phases and pressures. At speed range of 2 000—3 500 r/min，near-zero NO_x emission could be achieved at an average effective pressure exceeding 1 MPa and the power output is 2.6 times higher than that under the naturally aspirated condition. It is found that the highest brake mean effective pressure and brake thermal efficiency can be achieved when the end of hydrogen injection timing is 80° CA BTDC. After optimization，the hydrogen engine reaches the maximum torque of 204 N·m at 2 500 r/ min，the maximum power of 72 kW at 3 500 r/min and the highest effective thermal efficiency of 41.5% at 2 000 r/ min. Near-zero NO_x emission range covers the common operating conditions of passenger cars. The experimental results are used to develop control strategies for the high-efficiency near-zero emission hydrogen engine.