Cycle resolved control for HCCI engine load range expansion by combining ion current and pressure sensor
Cycle resolved control for HCCI engine load range expansion by combining ion current and pressure sensor
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DOI：
10.1016/j.proci.2020.09.003
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发表时间：
2021-04-13
影响因子：
3.4
通讯作者：
Li, Liguang
中科院分区：
文献类型：
--
作者：
Zhu, Denghao;Deng, Jun;Li, Liguang
均质充量压燃（HCCI）在提高发动机效率和超低NOx原始排放方面具有很大的潜力。然而，HCCI燃烧的主要困难是点火的可控性，特别是在边界条件下。在这些条件下，可能发生随机的异常燃烧，例如不完全燃烧或爆震。传统的基于发动机图谱的控制不足以克服这些问题。需要实时的缸内燃烧诊断和循环分解燃烧控制。本文对均质压燃发动机负气门重叠（NVO）期间的电离过程进行了数值研究。通过实验验证了离子电流能反映燃料重整质量的大小。与其他仅使用单个传感器（压力传感器或离子电流传感器）的研究相比，本文首次将两个传感器结合起来，以提高诊断准确性。此外，第一次，在NVO期间的离子电流用于控制。实验在轻载和高载边界条件下进行。在轻负荷边界条件下，采用两种传感器组合的方法，对随机不完全燃烧的诊断准确率可达91.3%，与单独使用其中一种传感器相比，误判率降低了30%。在控制器被激活之后，CA 50（sigma（CA 50））和IMEP（sigma（IMEP））的标准偏差分别减小了14.6%和11.3%。对于高负荷边界条件，σ（CA 50）和？IMEP分别降低了12.3%和15.4%。此外，爆震强度降低了9%。最终，最小载荷的IMEP从0.23 MPa减小到0.18 MPa，扩展22%，最大载荷的IMEP从0.33 MPa扩展到0.4 MPa，扩展21%。(c)2020燃烧研究所爱思唯尔公司出版All rights reserved.
Homogeneous charge compression ignition (HCCI) offers a high potential in engine efficiency enhancement and ultra-low NOx raw emissions. However, the main difficulty in HCCI combustion is its controllability of the ignition, especially at boundary conditions. At these conditions, stochastic abnormal combustion may happen, such as incomplete combustion or knock. Traditional engine map-based control is not enough to overcome these problems. Real-time in-cylinder combustion diagnosis and cycle resolved combustion control are required. In this study, the ionization process during negative valve overlap (NVO) interval in HCCI engines is numerically studied. It is identified that the ion current can reflect the quality of fuel reforming, which has been validated in the experiments. Compared to other studies that only use a single sensor (pressure sensor or ion current sensor), here for the first time, two sensors are combined to enhance the diagnostic accuracy. Besides, for the first time, ion current during NVO is employed for control. The experiments were conducted both at light load and high load boundary conditions. For light load boundary condition, by combining two sensors, the diagnostic accuracy rate of stochastic incomplete combustion is about 91.3%, and the misjudgment rate is reduced by 30% compared to only use one of them. After the controller is activated, the standard deviations of CA50 ( sigma (CA50) ) and IMEP ( sigma (IMEP) ) are reduced by 14.6% and 11.3%, respectively. For high load boundary condition, sigma(CA50) and ?IMEP are reduced by 12.3% and 15.4% respectively. Besides, the knock intensity is reduced by 9%. Ultimately, IMEP of the minimal load is reduced from 0.23 MPa to 0.18 MPa with an extension of 22%, and IMEP of the maximum load is expanded from 0.33 MPa to 0.4 MPa with an expansion of 21%.(c) 2020 The Combustion Institute. Published by Elsevier Inc. All rights reserved.