Abstract The understanding of reactivity controlled compression ignition has greatly improved throughout recent years. While its potential for extremely low NO x and soot emissions has been confirmed numerous times, there remain some ambiguities about the ability of this concept to attain very high efficiency. Now that increasingly stringent CO 2 regulations come into effect worldwide, it is particularly the efficiency aspect that is of great interest. This work combines a heat release study with regression analysis to identify the influence of combustion parameters on the heat release rate shape and the relation it has with efficiency and associated loss channels. A metric called burn ratio is introduced as the ratio of burn durations after and before the centroid of combustion. The burn ratio is found to correlate well to fuel reactivity stratification, and generally characterizes the heat release rate shape. Further regression analysis revealed a synergy between fuel reactivity stratification and the intake manifold pressure. Heavily boosted conditions and relatively early diesel injections result in a notable suppression of heat transfer losses, although some stratification remains necessary to find a balance between heat loss and combustion efficiency. Specifically, this balance is essential to achieve high gross indicated efficiency, for which the burn ratio is finally used to optimize fuel injection.

中文翻译：

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以 E85 和柴油为燃料的重型 RCCI 发动机中最佳总指示效率的热释放率整形

摘要 近年来，对反应性控制压燃的理解有了很大的提高。虽然其极低 NO x 和烟尘排放的潜力已被多次证实，但关于该概念获得非常高效率的能力仍存在一些模糊性。现在越来越严格的 CO 2 法规在全球范围内生效，特别是效率方面引起了极大的兴趣。这项工作将放热研究与回归分析相结合，以确定燃烧参数对放热率形状的影响及其与效率和相关损失通道的关系。作为燃烧质心前后燃烧持续时间的比率，引入了称为燃烧比的度量。发现燃烧比与燃料反应性分层密切相关，并且通常表征放热率形状。进一步的回归分析揭示了燃料反应性分层和进气歧管压力之间的协同作用。大幅提升的条件和相对较早的柴油喷射导致热传递损失的显着抑制，尽管仍然需要进行一些分层以找到热损失和燃烧效率之间的平衡。具体来说，这种平衡对于实现高总指示效率至关重要，为此燃烧比最终用于优化燃料喷射。大幅提升的条件和相对较早的柴油喷射导致热传递损失的显着抑制，尽管仍然需要进行一些分层以找到热损失和燃烧效率之间的平衡。具体来说，这种平衡对于实现高总指示效率至关重要，为此燃烧比最终用于优化燃料喷射。大幅提升的条件和相对较早的柴油喷射导致热传递损失的显着抑制，尽管仍然需要进行一些分层以找到热损失和燃烧效率之间的平衡。具体来说，这种平衡对于实现高总指示效率至关重要，为此燃烧比最终用于优化燃料喷射。