Advanced Control on Multi-Mode Combustion Diesel Engines during Transient Operations

燃油经济性和发动机排放是世界范围内交通运输领域的关键问题。为了有效地解决这些问题，先进的燃烧模式，如HCCI(均质充气压缩点火)、LTC(低温燃烧)、PCCI(预混充气压缩点火)，通过允许发动机在接近峰值效率的情况下运行，显示了巨大的优势。根据美国能源部最近发布的年度进展报告，使用先进的燃烧模式有可能将重型发动机的燃油效率提高到高达55%，将轻型汽车的燃油效率提高到35%到50%。 要实现先进燃烧的广泛采用，必须克服控制中的两个重要障碍。一是先进的燃烧模式通常发生在自动点火时(即没有明确的燃烧启动指示器)，因此需要更全面地考虑和控制缸内条件。另一个挑战在于当燃烧模式因发动机运行条件不同而改变时的瞬变控制。对发动机效率和安全性至关重要的是形状良好的轨迹，它可以避免在瞬时运行过程中发生不必要的中间燃烧。 这项研究将通过以下几个方面来解决这些挑战：1.开发稳健的缸内状态建模和估计方法，该方法可以通过现成的进气/排气歧管测量数据有效地提取缸内状态信息；2.研究先进的燃烧模式和暂态动力学；3.实现一种新的非线性暂态控制方法，称为非平衡暂态轨迹成形(NETTS)，以解决燃烧模式切换中的不良暂态影响。

Fuel economy and engine emissions are critical issues in transportation sector worldwide. To effectively handle these issues, advanced combustion modes, such as HCCI (homogeneous charge compression ignition), LTC (low temperature combustion), PCCI (premixed charge compression ignition), have shown substantial advantages by allowing engines to operate near their peak efficiency. According to the recent annual progress report from the U.S. Department of Energy, using advanced combustion modes has the potential to increase the fuel efficiency of heavy duty engine to as high as 55%, and that of the light-duty vehicle to the range of 35% to 50%. To achieve a broad adoption of advanced combustion, two important barriers in control must be overcome. One is that advanced combustion mode typically occurs with auto-ignition (i.e., lack of an explicit start of combustion indicator), and thus requires a more comprehensive consideration and control of the in-cylinder conditions. The other challenge lies in the control of transients when combustion modes change due to different engine operation conditions. Critical to engine efficiency and safety are well-shaped trajectories which avoid undesired intermediate combustion during the transient operations. This proposed research will focus on solving these challenges by: 1. Developing robust in-cylinder condition modeling and estimation methods, which can effectively extract the in-cylinder condition information by readily available measurements from the intake/exhaust manifolds; 2. Investigating the advanced combustion modes and transient dynamics; 3. Implementing a novel nonlinear transient control methodology, referred to as Non-Equilibrium Transient Trajectory Shaping (NETTS), to tackle undesirable transient effects in combustion mode switchings.