使用電磁氣閥於汽油引擎之效率改善

改善火花點火SI引擎中燃油消耗與廢氣排放等問題對於車輛產業研究是一門相當重要的議題。目前已有許多解決方法如混合動力、電動車、燃料電池、GDI直噴、VCR可變壓縮比等技術，而針對SI引擎來說，VVT可變汽門正時與CDA汽缸休止技術可以最有效且直接改善油耗與廢排的性能表現。以EMV電子氣閥技術應用的引擎可以消除節流閥的流量限制，而使用根據不同負載下停用部分汽缸的汽缸休止技術也可擁有較高的指示平均有效壓力IMEP，相對的也能大幅降低pumping loss。另一方面，電子氣閥能達到連續性的控制氣門正時，也都能更加改善引擎效率、提升性能表現。目前就眾多VVT與CDA的技術當中，以永磁電磁複合式電子氣閥 ( PM/EM Hybrid EMV ) 最有發展潛力。為克服傳統EMV的缺點，本研究將探討一種新型永磁電磁複合式電子氣閥，使用磁路分析軟體設計最佳化參數。並針對SI引擎的汽門動態響應提出EMV汽門緩接觸控制策略。而利用永磁的磁力吸附汽門電樞並以驅動電流釋放的控制方法，比起傳統EMV機構可以更有效的達到節能效果。　　本研究另外針對無節流閥SI引擎之循環建立動態模型，並模擬包含EMV電子氣閥與汽缸休止技術，而模擬結果顯示出在不同轉速下的最佳汽門正時：進氣閥門關閉的最佳正時隨著引擎轉速有線性的變化，而開啟的時機對引擎性能並沒有顯著的影響。另外本研究指出引擎在不同負荷下進行汽缸休止模式也可成功的提高引擎效率，並針對引擎全範圍的負載設計出不同的汽缸休止控制策略。結果顯示引擎於低負載時令兩汽缸進行休止 (50% CDA) 可明顯改善燃油消耗量，而引擎中負載時使單汽缸休止 (25% CDA) 可以讓燃油消耗有最佳表現。SI引擎搭配恰當的VVT與CDA控制策略，可使其引擎效能於低負載時增加30%以上，中負載時增加11.7%。

關鍵字

可變汽門正時；電子氣閥；汽缸休止技術；無凸輪引擎；無節流閥引擎；緩接觸；磁通量；引擎效率

並列摘要

Improving fuel consumption and emission in SI engines are an important issue for engine researchers and manufacturers. There are many methods to solve these problems as hybrid vehicle, electric vehicle, fuel cell, new energy, gasoline direct injection (GDI), variable ratio compression (VCR), etc. Meanwhile, variable valve timing (VVT) and cylinder deactivation (CDA) are promising methods in reducing fuel consumption and emission in SI engines. An SI engine which uses electromagnetic valve train (EMV) will eliminate flow restriction from the throttle valve and produce higher indicated mean efficiency pressure (IMEP) due to the disabling of some of the working cylinders at part load. Therefore, pumping loss can be significantly reduced at part-load conditions. In addition, duration and timing of valve events are variably controlled at different operating conditions. This contributes to the improvement of engine efficiency. Several techniques have been developed to perform VVT and CDA. An EMV with permanent magnet and electromagnetic coils (PM/EM) installed together is the most potential. In this study, a new hybrid EMV with PM/EM, which significantly differs from existing EMVs, has been designed to overcome the drawbacks of conventional EMVs. Magnetic simulation has been applied to analyze the magnetic flux and to optimize EMV parameters. Moreover, the study presents soft landing control strategies that can fully satisfy the valve dynamics in SI engines. The way of utilizing PM and optimal actuating current to catch and release valves has many advantages in energy consumption for valve catching and releasing when compared with other EMVs The study also develops a dynamic model of an unthrottled camless SI engine to simulate the engine cycle. The model uses an EMV system that allows valve train control and cylinder deactivation techniques to be carried out in simulation flexibly. The simulated results show the optimal valve timing for different engine speeds. The optimal timing of intake valve closing depends on engine speed linearly, while the intake valve opening insignificantly influences engine performance. Additionally, this study also shows that cylinder deactivation modes can be successfully applied in improving engine efficiency at different engine loads. Different cylinder deactivation strategies have been applied for the full range of engine loads. The study concludes that the two-cylinder deactivation mode (50% CDA) considerably improves fuel consumption at low engine load. Meanwhile, one-cylinder deactivation (25% CDA) is an optimal fuel economy mode at medium engine load. With proper uses of VVT and CDA strategies, the efficiency of an SI engine can be increased more than 30% at low engine load and 11.7 % at medium engine load.

並列關鍵字

Variable valve timing ； electromagnetic valve train ； cylinder deactivation ； camless engine ； unthrotted engine ； soft landing ； magnetic flux ； engine efficiency

參考文獻

[37] Y. Shiao and Y. J. Zheng, “The Dynamic Analysis and Actuation of a New Hybrid Electromagnetic Valve for Engines,” Journal of National Taipei University of Technology., vol. 44–2, pp. 1–15, 2012.

[44] L. An, Actuation and Analysis of a New Hybrid Electromagnetic Valve for a Camless Engines, Master Thesis, National Taipei University of Technology, Taiwan, 2011.

[1] O. A. Kutlar, H. Arslan, and A. T. Calik, “Methods to Improve Efficiency of Four Stroke, Spark Ignition Engines at Part Load,” Energy Conversion and Management, vol. 46, no. 20, pp. 3202–3220, Dec. 2005.

[2] N. Milovanovic, D. Blundell, S. Gedge, and J. Turner, “Cam Profile Switching ( CPS ) and Phasing Strategy vs Fully Variable Valve Train ( FVVT ) Strategy for Transitions between Spark Ignition and Controlled Auto Ignition Modes,” SAE 2005-01-0766, 2005.

[3] G. Maas, H. Neukirchner, O. Dingel, and O. Predelli, “Potential of an Innovative , Fully Variable Valvetrain,” SAE 2004-01-1393, 2004.

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使用電磁氣閥於汽油引擎之效率改善

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