IJE TRANSACTIONS C: Aspects Vol. 27, No. 9 (September 2014) 1449-1456    Article Under Proof

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M. Delkhosh, M. SaadatFoumani and P. Rostami
( Received: August 12, 2013 – Accepted: May 22, 2014 )

Abstract    Among different goals defined in vehicle design process, fuel consumption (FC) is one of the most important objectives, which significantly has taken into account lately, both by the customers and vehicle manufacturers. One of the significant parameters which impacts the vehicle FC is the efficiency of vehicle's power train. In this paper, a half-toroidal continuously variable transmission (CVT) is considered as the vehicle power train. Its efficiency is sensitive to its geometry, and variation of its geometry can result the vehicle FC reduction. On the other hand, geometry variation affects its weight and fatigue life, which are considered as major contributing factors in the power train design. This paper aims to optimize half-toroidal CVT in order to minimize its weight, FC of the vehicle equipped with it, and provide the desired fatigue life. After introducing half-toroidal CVT, the method of calculating the mentioned objective functions is presented. A specific importance weight for each objective is considered. These weights are functions of their related objectives. A single objective optimization is implemented for each objective, and their optimal values are obtained. Then, these objectives are optimized simultaneously using Global Criterion method.


Keywords    Continuously Variable Transmission, Half-Toroidal, Fuel Consumption, Fatigue Life, Multi-objective Optimization, Importance Weight, Global Criterion



در میان اهداف معرفی شده در پروسه طراحی خودرو یکی از مهمترین معیارها مقدار مصرف سوخت خودرو است، که مدنظر هر دو گروه سازنده خودرو و مشتری است. یکی از پارامترهای موثر بر مصرف سوخت خودرو، بازده سیستم انتقال قدرت است. در این مقاله سیستم انتقال قدرت پیوسته (CVT) نصف چنبره، به عنوان سیستم انتقال قدرت خودرو در نظر گرفته می­شود. بازده این مجموعه به هندسه آن وابسته است و تغییر آن می­تواند به کاهش مصرف سوخت خودرو انجامد. از طرفی، تغییر هندسه آن روی وزن و عمر خستگی آن نیز تاثیر می­گذارد. در این مقاله، هدف بهینه­سازی CVT نصف چنبره در جهت کاهش مصرف سوخت خودرو، کاهش وزن آن و تامین مطلوبات سازنده در زمینه عمر خستگی آن است. پس از معرفی CVT نصف چنبره، روش محاسبه توابع هدف بیان شده ارائه می­شود. برای هر کدام از این توابع یک ضریب وزنی تعریف می­شود که مقدار آن به مقدار تابع هدف بستگی دارد. هرکدام از توابع هدف به تنهایی بهینه می­شوند و مقادیر بهینه آنها بدست می­آید. در نهایت، این توابع هدف به صورت همزمان به کمک روش Global Criterion بهینه­یابی می­شوند.



1.     Ebrahimi, R. and Mercier, M., "Experimental study of performance of spark ignition engine with gasoline and natural gas", International Journal of Engineering,  Vol. 24, (2010), 65-74.

2.     Yousufuddin, S. and Mehdi, S.N., "Effect of ignition timing, equivalence ratio, and compression ratio on the performance and emission characteristics of a variable compression ratio si engine using ethanol unleaded gasoline blends", International Journal of Engineering Transactions B: Applications,  Vol. 21, No. 1, (2008), 97-106.

3.     Delkhosh, M. and Foumani, M.S., "Optimisation of full-toroidal continuously variable transmission in conjunction with fixed ratio mechanism using particle swarm optimisation", Vehicle System Dynamics,  Vol. 51, No. 5, (2013), 671-683.

4.     Delkhosh, M., Foumani, M.S. and Boroushaki, M., "Geometrical optimization of parallel infinitely variable transmission to decrease vehicle fuel consumption", Mechanics Based Design of Structures and Machines,  Vol. 42, No. 4, (2014), 483-501.

5.     He, H., Li, H., Qin, D. and He, P., "Optimization design for structural parameters of toroidal cvt for automobiles", Journal of Mechanical Engineering,  Vol. 5, (2009), 47-60.

6.     Akbarzadeh, S. and Zohoor, H., Sensitivity analysis of torque transmission efficiency of a half-toroidal CVT., SAE Technical Paper. (2006)

7.     Delkhosh, M., Foumani, M.S., Boroushaki, M., Ekhtiari, M. and Dehghani, M., "Geometrical optimization of half toroidal continuously variable transmission using particle swarm optimization", Scientia Iranica,  Vol. 18, No. 5, (2011), 1126-1132.

8.     Delkhosh, M. and Foumani, M.S., "Multi-objective geometrical optimization of full toroidal CVT", International Journal of Automotive Technology,  Vol. 14, No. 5, (2013), 707-715.

9.     Delkhosh, M. and Foumani, M.S., "Modelling and optimization of toroidal continuously variable transmission in ece driving cycle", International Journal of Engineering,  Vol. 26, No. 12, (2013), 1535-1542.

10.   Carbone, G., Mangialardi, L. and Mantriota, G., "A comparison of the performances of full and half toroidal traction drives", Mechanism and Machine Theory,  Vol. 39, No. 9, (2004), 921-942.

11.   Attia, N.A., Datong, Q., Wankai, S. and Huaying, L., "A parametric study on the contact stress of half toroidal continuously variable transmission", Journal of Chongqing University,  Vol. 2, No. 2, (2003).

12.   Budynas R.  and Nisbett K., "Shigley’s mechanical engineering design, 9th edition", McGraw-Hill Science/Engineering/Math,  ., (2010).

13.   Machida, M. and Murakami, Y., "Development of the half toroidal cvt powertors unit", NSK Tech. J,  Vol. 9, No. 669, (2000), 15-26.

14.   Dutta-Roy, T. and Zhang, N., "Effect of a half-toroidal continuously variable unit on the dynamics of a complete powertrain: A parametric free vibration analysis", Proceedings of the Institution of Mechanical Engineers, Part D: Journal of Automobile Engineering,  Vol. 218, No. 5, (2004), 471-484.

15.   De Weck, O.L., "Multiobjective optimization: History and promise", in Invited Keynote Paper, GL2-2, The Third China-Japan-Korea Joint Symposium on Optimization of Structural and Mechanical Systems, Kanazawa, Japan. Vol. 2, (2004).

16.   deWeck O.L.  and Kim I.Y., "Multiobjective optimization via the adaptive weighted sum method", 10th AIAA/ISSMO Multidisciplinary Analysis and Optimization Conference, Albany, New York,, (2004).

17.   Statnikov, R.B. and Matusov, J.B., "Multicriteria optimization and engineering, Chapman and Hall,  (1995).

18.   Marler, R.T. and Arora, J.S., "Survey of multi-objective optimization methods for engineering", Structural and Multidisciplinary Optimization,  Vol. 26, No. 6, (2004), 369-395.

19.   Das, I. and Dennis, J.E., "A closer look at drawbacks of minimizing weighted sums of objectives for pareto set generation in multicriteria optimization problems", Structural Optimization,  Vol. 14, No. 1, (1997), 63-69.

20.   Rao, S.S. and Rao, S., "Engineering optimization: Theory and practice", John Wiley & Sons,  (2009).

21.   Yu, P.-L., "A class of solutions for group decision problems", Management Science,  Vol. 19, No. 8, (1973), 936-946.

22.   Wu, J., Zhang, C.-H. and Cui, N.-X., "Pso algorithm-based parameter optimization for hev powertrain and its control strategy", International Journal of Automotive Technology,  Vol. 9, No. 1, (2008), 53-59.

23.   Yeniay, O., "Penalty function methods for constrained optimization with genetic algorithms", Mathematical and Computational Applications,  Vol. 10, No. 1, (2005), 45-56.

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