Study on influence of fuel injection parameters on combustion and emission characteristics of biodiesel engine

燃油喷射参数对生物柴油发动机燃烧与排放特性影响研究

College of Power Engineering, Naval University of Engineering, Wuhan 430033, China

Received: 27 August 2024

Abstract

Based on the dual solenoid valve control strategy of ultra-high pressure fuel injection device to achieve ultra-high pressure and variable law injection, a simulation model of the combustion process of biodiesel engine was established, and the model was modified and verified by experimental data. Then, the influence of the combustion and emission performance of biodiesel engine on the injection characteristics (injection pressure and injection law) was studied. The results indicate that when a certain control strategy is adopted to adjust the opening and closing timing of the solenoid valves in the fuel injector and electronic supercharger, ultra-high pressure and variable injection law can be achieved. Under the saddle-shaped fuel injection law, a higher injection pressure is beneficial for the mixing of fuel and air in the cylinder, which can improve fuel atomization and reducing soot emissions. When the fuel injection law changes from rectangular shape to sloping shape, and then to saddle-shaped, the maximum cylinder pressure and cylinder temperature of the biodiesel engine gradually decrease, resulting in better fuel air mixing and more complete combustion, additionally the NO_x generation decreases by 42.8% while the soot generation only increases by 1.8%.

摘要

在通过超高压燃油喷射装置双电磁阀控制策略实现超高压力和可调喷油规律喷射的基础上, 建立了生物柴油发动机燃烧过程模型, 并基于试验数据对模型展开了准确性验证, 而后研究了生物柴油发动机燃烧排放性能随喷油特性(喷油压力和喷油规律)的变化规律。结果表明: 当采用一定的控制策略, 调整喷油器和电控增压器中的电磁阀开启和关闭时序后, 能够实现超高压力和可变喷油规律喷射; 靴形喷油规律下, 喷油压力较大有利于缸内燃油和空气的混合, 提升燃油雾化效果, 降低Soot排放; 当喷油规律由矩形变为斜坡形, 再转变为靴形时, 生物柴油发动机缸压和缸温最高值逐渐降低, 缸内油气混合效果更好, 燃烧更充分, 并且NO_x生成量下降42.8%, 而Soot生成量仅上升1.8%。