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以降低微粒排放为目标,在一台带旁通阀的二级涡轮增压重型柴油机上探索了不同油压策略对柴油机恒转速增转矩5s典型瞬变过程燃烧及微粒排放的影响。研究结果表明:二级涡轮增压器有助于改善柴油机负荷加载瞬变过程空气量供给,旁通阀关闭时采用全程增油压方式可有效降低瞬变过程烟度排放峰值;但随着旁通阀开度增大,提高油压却使烟度峰值不降反升;在旁通阀小开度下采用分段增油压策略,有助于改善发动机负荷加载初期缸内燃烧热力学状态,促进中大负荷阶段油气充分混合,并在10%旁通阀开度下实现最大烟度峰值降幅达51.5%;旁通阀开度增大也会导致燃油经济性恶化,而采用分段增油压策略能够有效抑制这一恶化趋势。
In order to reduce the particle emission, a two-stage turbocharged heavy-duty diesel engine with bypass valve was used to explore the effect of different hydraulic strategies on the combustion and particulate emissions of 5s typical transient process of diesel engine with constant rotating speed. The results show that the two-stage turbocharger can help to improve the air supply during the load transient of diesel engine. When the by-pass valve is closed, the total oil pressure increase can effectively reduce the smoke emission peak during transient process. However, Increasing the opening of the valve increases the hydraulic pressure so that the smoke peak does not fall or rise; using a bypass hydraulic valve with a small opening increases the thermodynamic state of combustion in the initial stage of engine load loading, To promote medium and large load phase of oil and gas mixture, and at the opening of 10% bypass valve maximum smoke peak reduction of 51.5%; bypass valve opening will lead to deterioration of fuel economy, and the use of sub-oil Pressure strategy can effectively inhibit this deterioration trend.