二级增压柴油机压缩比和喷油提前角优化研究

为解决某V型柴油机由单级增压改为二级增压后，最高燃烧压力过高问题，通过GT-Power软件建立柴油机仿真模型，利用试验数据进行校核，仿真研究了喷油提前角和压缩比对二级增压柴油机性能及最高燃烧压力的影响规律。以二级增压柴油机的试验最高燃烧压力作为限制条件，以转矩达到最大为目标，利用GT-POWER中的DOE工具对喷油提前角和压缩比进行联合优化。仿真结果表明：降低压缩比能够有效降低最大转矩点(1 300 r/min)和标定点(2 100 r/min)的最高燃烧压力，压缩比每降低1，最大转矩点最高燃烧压力降低0.8 MPa，标定点最高燃烧压力降低1.16 MPa；得出优化后的压缩比和喷油提前角相对变化值为14.9°CA和4.3°CA. 根据试验机的结构条件，利用试验机在柴油机台架上验证了优化结果的可行性。

Research on Compression Ratio and Fuel Injection Advance Angle Optimization of Two-stage Turbocharged Diesel Engine

To address the issue that the maximum combustion pressure is too high after a certain V shape diesel engine is modified into two-stage turbocharged system from one-stage turbocharged system, the effects of fuel injection advance angle and compression ratio on the performance and maximum combustion pressure of two-stage turbocharged diesel engine are simulated by building a simulation model on the software GT-Power and using experimental data, and the united optimization of both the fuel injection advance angle and compression ratio is conducted with the tool DOE of GT-Power by taking experimental maximum combustion pressure of the two-stage turbocharged engines as limitation and taking the maximum torque as goal. The decrease of the compression ratio can effectively reduces the maximum combustion pressure at 1 300 rpm and 2 100 rpm. For every 1 decreased in the compression ratio, the maximum combustion pressure is decreased by 0.8 MPa at 1 300 rpm and 1.16 MPa at 2 100 rpm, respectively. Relative variations of optimized compression ratio and fuel injection advance angle are 14.9°CA and 4.3°CA, respectively. The feasibility of the result is validated according to the structural condition of the testing diesel engine. Verification with trial machine is conducted on diesel engine bench.