New Operating Strategies Afforded by Fully Variable Valve Trains
New Operating Strategies Afforded by Fully Variable Valve Trains
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全可变气门机构提供新的操作策略
DOI：
10.4271/2004-01-1386
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发表时间：
2004
期刊：
影响因子：
--
通讯作者：
K. Douglas
中科院分区：
文献类型：
--
作者：
J. Turner;M. Bassett;R. Pearson;G. Pitcher;K. Douglas
用于四冲程发动机的电动液压和机电气门机构技术正在出现，其允许比使用基于机械的系统能够实现的气门事件的更大的灵活性和控制。在利用这些系统的益处方面所做的大部分工作都是针对改善发动机燃料经济性和减少排放。在目前的工作中，已经进行了研究，使用发动机模拟程序，在一些可能的好处，发动机的性能，可能会促进完全可变气门机构（FVVT）系统的灵活性。模拟研究表明，FVVT系统，由现实的打开和关闭率的限制，提供足够的范围内的阀门事件的持续时间和定时，使发动机产生非常高的特定输出，同时实现高水平的扭矩在低速和中速范围。它还表明，一个FVVT系统可以修改基本的进气歧管调整机制，通过修改发动机点火顺序，而不求助于可变几何歧管系统。此外，一个“气动混合”的概念的操作进行了研究，并进一步的操作策略，包括差动缸加载，这成为可行的FVVT系统后，通过也进行了讨论。
Electrohydraulic and electromechanical valve train technologies for four-stroke engines are emerging which allow much greater flexibility and control of the valve events than can be achieved using mechanically-based systems. Much of the work done on exploiting the benefits of these systems has been directed towards improving engine fuel economy and reducing emissions. In the present work a study has been made, using an engine simulation program, in to some of the possible benefits to engine performance that may be facilitated by the flexibility of fully variable valve train (FVVT) systems. The simulation study indicates that FVVT systems, limited by realistic opening and closing rates, provide sufficient range in the valve event duration and timing to enable the engine to produce very high specific outputs whilst achieving a high level of torque in the low- and mid-speed range. It is also shown that an FVVT system makes it possible to modify the basic intake manifold tuning mechanism by modifying the engine firing order, without recourse to variable geometry manifold systems. Additionally, the operation of a 'pneumatic hybridisation' concept are investigated and a range of further operating strategies, including Differential Cylinder Loading, which become viable upon the adoption of FVVT systems are also discussed.