针对某天然气发动机的稳压式进气管进气均匀性较差的问题，综合考虑配气相位、燃气混合及各缸进气流量分配，采用一三维耦合数值仿真手段进行了改进优化。试验结果表明，采用改进后的进气管在机组功率为额定功率的80%以上时，各缸的爆压不均匀性控制在1.5%以内，很好地解决了各缸工作均匀性较差和排温差别较大的问题，为功率的进一步提升提供了保障。

For the poor intake uniformity of constant-pressure intake manifold of natural gas engine, the 1D and 3D coupled numerical simulation was conducted to improve and optimize the intake manifold design by taking into consideration the valve timing, fuel and air mixing and airflow distribution for each cylinder comprehensively. The experimental results show that the unevenness of peak cylinder pressure between cylinders can be controlled within 1.5% by using the modified intake manifold when the power of generation sets is over 80% of the nominal power. The poor intake uniformity of each cylinder and great difference between exhaust temperatures are solved well through the modifications, which provides the basis for further improvement of power.