Deresso Habtamu, Nallamothu Ramesh Babu, Ancha Venkata Ramayya, Yoseph Bisrat
Department of Mechanical Engineering, Adama Science and Technology University, Adama, Ethiopia.
Department of Mechanical Engineering, Jimma University Institute of Technology, Jimma, Ethiopia.
Heliyon. 2022 May 31;8(6):e09602. doi: 10.1016/j.heliyon.2022.e09602. eCollection 2022 Jun.
Diesel engine is the prime mover on land transportation industry and used in a variety of power generation applications due to their higher fuel efficiency. However, the engine research community faces a major hurdle rigorous restriction introduced in the Glob to reduce pollutant emissions from internal combustion engines. Different piston bowl shape designs allows more precise mixing before combustion to enhance in the optimization using computational calculations to reduce emissions. The investigation was to reduce the NOx and PM emissions using combustion simulation comparing with each piston of a single-cylinder engine at a CR of 24, 4-stroke, and water-cooled Engine. The four piston bowl shapes of DSEVL2 BMW M47T, Shallow Hesselman, Lombardini 15LD350, and DOOSANP158FE were analyzed by the Diesel-RK combustion simulation. After successful validating; the simulation model shows that the peak cylinder pressure of Piston-2 is 131bar and the peak cylinder pressure of Piston-4 is 113bar. The Maximum Cylinder Temperature of the Piston-2 is 2048.2k, and the lowest value of Cylinder Temperature of the Piston-4 is 1680.9k the cylinder temperature of Piston-2 is 18% higher than Cylinder Temperature of Piston-4. The simulation result indicates that the temperature is within the acceptable limit in between 1400-2000k except for the piston temperature of 2048.2k. The PHRR of the Piston-3 is 0.082 with great variation in between maximum and minimum due to the presence of pre-and post-injection, the HRR-P4 is 0.035 J/°CA with the single injections. The HRR of the Piston-3 is the highest while HRR of the Piston-4 lowest with 39%. The NOx in the exhaust gas is 25.62 in the NOx piston-1; 16 in NOx of Piston-2, 18.2 in NOx-P3, and NOx-P4 is 12.74 g/kWh respectively. The NOx of the NOx-P2 is lower than first and second piston due to the lower fuel fraction of NWF dilution outer the sleeve, low fuel fraction in core of the free spray, low fuel fraction in fronts of the free spray, low fuel fraction in the core of the fuel free spray. The Particulate Matter emission in PM-P1 is 0.35, and PM-P2 is 0.43 g/kWh which is higher than all the other. Although there is a substantial decrease in PM, a penalty in NOx is observed for PM-P1 but PM of the P2 is higher after the peak result of emission.
柴油发动机是陆地运输行业的主要动力源，由于其燃油效率较高，还被应用于各种发电领域。然而，发动机研究领域面临着一项重大障碍，即全球范围内为减少内燃机污染物排放而出台的严格限制。不同的活塞碗形状设计能够在燃烧前实现更精确的混合，从而通过计算优化来减少排放。本研究旨在通过燃烧模拟，比较一台压缩比为24、四冲程、水冷的单缸发动机的各个活塞，以降低氮氧化物（NOx）和颗粒物（PM）排放。利用Diesel-RK燃烧模拟分析了DSEVL2宝马M47T、浅赫塞尔曼、 Lombardini 15LD350和斗山P158FE这四种活塞碗形状。在成功验证之后，模拟模型显示活塞2的最高气缸压力为131巴，活塞4的最高气缸压力为113巴。活塞2的最高气缸温度为2048.2K，活塞4的最低气缸温度为1680.9K，活塞2的气缸温度比活塞4的高18%。模拟结果表明，除了活塞温度为2048.2K外，温度在1400 - 2000K的可接受范围内。由于存在预喷射和后喷射，活塞3的热释放速率（PHRR）为0.082，最大值和最小值之间变化很大，活塞4单次喷射时的热释放速率（HRR-P4）为0.035 J/°CA。活塞3的热释放速率最高，而活塞4的热释放速率最低，相差39%。排气中的氮氧化物，活塞1为25.62，活塞2为16，活塞3为18.2，活塞4为12.74 g/kWh。活塞2的氮氧化物含量低于第一和第二个活塞，这是由于套筒外部NWF稀释的燃油比例较低、自由喷雾核心区域的燃油比例较低、自由喷雾前端的燃油比例较低、无燃油自由喷雾核心区域的燃油比例较低。活塞1的颗粒物排放（PM-P1）为0.35，活塞2的颗粒物排放（PM-P2）为0.43 g/kWh，高于所有其他活塞。尽管颗粒物排放大幅下降，但活塞1在颗粒物排放方面氮氧化物有所增加，不过在排放峰值后活塞2的颗粒物排放更高。
