Y Xác định hệ số khối lượng quay phục vụ việc mô phỏng động lực học chuyển động của ô tô

is a coefficient that takes into account the effect of rotating parts of the crankshaft mechanism and the drivetrain system on the driving dynamics of cars. The paper presents the results of the research to determine the rotation mass coefficient of Hyundai Starex by theory (based on the experimental data set of rotation details of the crankshaft mechanism, components of the drivetrain system and use of Inventor software) combined with experimentation (test vehicle on a roller test bed). The research results are used as input parameters for simulation models, calculating parameters for evaluating the quality of linear motion dynamics of Hyundai Starex cars. Keywords: Moment of inertia; rotating mass coefficient; roller test platform (Chassis Dynamometer). Túm tắt Hệ số khối lượng quay (γ m ) là hệ số kể đến ảnh hưởng của cỏc chi tiết chuyển động quay của cơ cấu khuỷu trục thanh truyền và hệ thống truyền lực đến động lực học chuyển động của ụtụ. Bài bỏo trỡnh bày kết quả nghiờn cứu xỏc định hệ số khối lượng quay của xe Hyundai Starex bằng lý thuyết (dựa trờn bộ dữ liệu đo thực nghiệm cỏc chi tiết chuyển động quay của cơ cấu khuỷu trục thanh truyền, cỏc bộ phận thuộc hệ thống truyền lực và sử dụng phần mềm Inventor) kết hợp với thực nghiệm (thử xe trờn bệ thử con lĕn). Kết quả nghiờn cứu được dựng làm thụng số đầu vào cho mụ hỡnh mụ phỏng, tớnh toỏn cỏc thụng số đỏnh giỏ chất lượng động lực học chuyển động thẳng của xe Hyundai Starex. Từ khúa: Moment quỏn tớnh; hệ số khối lượng quay; bệ thử con lĕn (Chassis Dynamometer). 1. INTRODUCTION The inertial force has a great influence on the linear motion of the vehicle when accelerating or decelerating. The inertial force consists of two components: The inertial force of linear motion and the inertial force of rotational motion. The inertial force of linear motion depends on the vehicle’s mass and its acceleration. Meanwhile, the inertial resistance of rotation is dependent on the moment of inertia and angular acceleration of all rotating parts starting from the transmission crankshaft of the engine to the active wheel of the vehicle. To simplify the calculation of driving dynamics, rotation coefficient (γ m ) is often used when considering the effect of rotational inertia drag [1, 2]. However, because the exact determination of rotational mass coefficient is quite complicated, some studies [4, 6] often use the following empirical formulas [1, 2]: (1) In which: ξ0 - Gear ratio of the powertrain. We see that the determination of γ m according to 201.04 0.0025mg x= + Reviewer: 1. Assoc.Prof.Dr. Tran Van Nhu 2. Assoc.Prof.Dr. Le Van Quynh LIấN NGÀNH CƠ KHÍ - ĐỘNG LỰC 55Tạp chớ Nghiờn cứu khoa học, Trường Đại học Sao Đỏ, ISSN 1859-4190, Số 1 (68) 2020 formula (1) has not included the specific structural characteristics of the engine and the powertrain of the vehicle. The experimental coefficients in (1) are fixed, so there is not enough basis to be able to choose an appropriate vehicle. Moreover, in specialized software that simulates the dynamics of vehicles such as GT-Drive, Simdriveline in Matlab/Simulink. It is necessary to have input about inertia moment parameters of each cluster such as engine, gearbox, cardan shaft, active bridge, wheel [10, 11]. Accurate and detailed determination of the rotating mass coefficient γ m according to the characteristics of the vehicle is difficult because it is necessary to identify inertia moment of many details in the structure of crankshaft mechanism, drivetrain system and tires. These details have a complex structure; some of them have heterogeneous materials and material distribution. Today, along with the development of simulation software (SolidWorks, Catia, Inventor...), the calculation of the inertia moment of the details is easier when there are sufficient structural parameters and their materials. The rotating mass coefficient is determined by calculation (theoretically) as above should also be checked and compared with the rotating mass coefficient determined experimentally with vehicles when operating on roller testing platforms. This paper presents the results of the research on determining the detailed rotating mass coefficient of Hyundai Starex cars by theory (using Inventor software combined with the measurement data set for dimensions, the volume of related details) combined with the experiment (on the roller testing platform, the active wheel of Hyundai Starex is forced to rotate by the roller of the testing platform). The research results are used as input parameters for the model of linear motion simulation of Hyundai Starex cars [5]. 2. THEORETICAL BASIS FOR DETERMINING THE ROTATING MASS COEFFICIENT The influence of rotating mass coefficient on the driving motion of the vehicle is determined by the formula [1]: (2) In which: γ m - The rotating mass coefficient; F - Traction at active wheels; ∑R - total drag of the road and air; m - vehicle mass; a - car acceleration. In formula (2), is determined by formula [1]: (3) In which: I w - moment of inertia of the active wheel; I 1 , I 2 ,...I n - moment of inertia of component rotating masses with corresponding gear ratios; ξ1, ξ2,...ξ3 rbx - rolling radius of wheels; I - rotating mass coefficient of total rotating components from the engine to the active wheel. According to [9], rotating mass coefficient ( zI ) for the axis of rotation of any solid object is determined by the formula: (4) In which: r - turning radius of the differential mass dm, m; r - density of material, kg/m3; dV - the volume of differential mass dm, m3. For components with relatively simple structures (cardan shaft, semi-axle, active wheel), Inventor software will be directly used for calculation and determination of rotating mass coefficient. For complex assemblies (crankshaft mechanism structure, gear box) will use a combination of calculation results from Inventor with the theoretical formulas to determine inertia moment. Inertia moment of the engine eI is determined by the formula, [8]: 2( )e cgi fw c cr c cyl fwI I I m m R n I= + = + + (5) With: cgiI - inertia moment of crankshaft and parts mounted on the shaft, [kg.m2]; fwI - inertia moment of flywheel, [kg.m2]; cm - Shaft mass, [kg]; crm - Big part volume, [kg]; cR - turning radius of crankshaft, [m]; cyln - Engine cylinder number. The inertia moment of a gearbox is determined by the formula [12]: mF R mag- =ồ 2 2 2w 1 1 2 2 2 2 2 2 21 ... 1n nm bx bx bx bx bx I I I I I mr mr mr mr mr x x xg = + + + + + = +ồ ồ ồ ồ 2 2. . .zI r dm r dVr= =ũ ũ NGHIấN CỨU KHOA HỌC 56 Tạp chớ Nghiờn cứu khoa học, Trường Đại học Sao Đỏ, ISSN 1859-4190, Số 1 (68) 2020 With: II - inertia moment of the primary shaft of gearbox (clutch shaft), [kg.m2]; III - inertia moment of intermediate axis, [kg.m2]; ai - the gear ratio of the gear pair always matches the gearbox; zkI - inertia moment of plain gear on secondary shaft, [kg.m2]; ki - transmission ratio of gearbox to gear pair of k gear; m - the number of plain gears on the secondary shaft; lI - inertia moment of reverse gear, [kg.m2]; li - the gear ratio of the number of reverse gears is calculated from the primary shaft of the gearbox to the regular reverse gears that are dynamically related to the gears on the intermediate shaft. 3. RESULTS OF DETERMINING THE ROTATING MASS COEFFICIENT 3.1. According to the theoretical method The object of the study is the engine and powertrain of the Hyundai Starex CVX (model 2008) with the main specifications shown in Table 1: Table 1. Main specifications of Hyundai Starex, [14] No Parameter Unit Value 1 Engine (Model: D4CB 2.5 TCI-A) Diesel, 4-stroke, 4-cylinder, 1-line, VGT turbocharger, using Common Rail-type injection system 2 Vehicle weight - Front axle - Rear axle kg 2,285 1,235 1,050 3 Base length ì Width m 3,2 ì 1,920 4 Gearbox ratios - 5 Gear 1 4,393 Gear 2 2,306 Gear 3 1,356 Gear 4 1,0 Gear 5 0,763 6 Tire radius m 0,3535 Due to the lack of detailed design documents of the crankshaft mechanism, drivetrain system, the author chose to directly determine the parameters of interest on the actual details of the engine and the vehicle with an appropriate measuring device. The results of building a 3D drawing of the main components in the crankshaft mechanism structure of the D4CB 2.5 TCI-A engine in Inventor software are shown in Figure 1. Figure 1. Figure (3D) key details of the crankshaft mechanism structure in 2014 Autodesk Inventor software The results of calculation and determination of the inertia moment of the crankshaft mechanism and drivetrain system of Hyundai Starex by the theoretical method are presented in Table 2. Table 2. Results of calculating the inertia moment of the crankshaft mechanism and drivetrain system No Inertia moment Unit Value 1 Inertia moment of engine, eI kg.m2 0,75 2 Inertia moment of transmission at gear 1, 1hI kg.m 2 0,0079 3 Inertia moment of transmission at gear 2, 2hI kg.m 2 0,0083 4 Inertia moment of transmission at gear 3, 3hI kg.m 2 0,0088 5 Inertia moment of transmission at gear 4, 4hI kg.m 2 0,0077 6 Inertia moment of transmission at gear 5, 5hI kg.m 2 0,0085 7 Inertia moment of cardan shaft, pI kg.m2 0,01152 8 Inertia moment of drive shaft, dI kg.m2 0,01389 9 Inertia moment of half shaft, dsI kg.m2 0,003 10 Inertia moment of wheel, wI kg.m2 1,26 Combining the data in Table 2 with formula (3) we will determine the total inertia moment and rotating mass coefficient of Hyundai Starex car with different manual numbers as shown in Table 3. 2 2 2 1 m h I II a zk k l l k I I I i I i I i- - - = = + + +ồ (6) LIấN NGÀNH CƠ KHÍ - ĐỘNG LỰC 57Tạp chớ Nghiờn cứu khoa học, Trường Đại học Sao Đỏ, ISSN 1859-4190, Số 1 (68) 2020 Table 3. Total inertia moment and rotating mass coefficient determined by theory No Specs Unit Gear 1 Gear 2 Gear 3 Gear 4 Gear 5 1 Total inertia moment, I LT kg.m2198,11 55,62 23,61 19,23 18,4 2 I e /I LT % 0,379 1,348 3,177 3,900 4,076 I h /I LT % 0,004 0,015 0,037 0,040 0,046 I p /I LT % 0,006 0,021 0,049 0,060 0,063 I d / I LT % 0,007 0,025 0,059 0,072 0,075 I ds /I LT % 0,002 0,005 0,013 0,016 0,016 I w / I LT % 0,636 2,265 5,337 6,552 6,848 3 Rotating mass coefficient, γ mLT 1,70 1,194 1,082 1,067 1,064 From Table 2 and Table 3, we see: Inertia moment of the active wheel accounts for the largest proportion in the total inertia moment (because the active wheel has the largest mass and turning radius) compared to the remaining components. However, according to formula (3), the impact of engine inertia moment on the total inertia moment is the largest because in addition to the engine having a relatively large inertia moment ( eI = 0,75), the ratio of engine to active wheel is the largest, especially when at No. 1, the transmission ratio of the powertrain is the largest (ξso1= 4,393 ì 3,615 = 15,881). 3.2. According to the experimental method 3.2.1. Experimental equipment The experiment of determining the rotating mass coefficient of Hyundai Starex is conducted on the 48 “roller test platform (at Chassis Dynamometer at Light Duty Test Cell of National Motor Vehicle Emission Test Center/Vietnam Register) with a layout. as shown in Figure 2. Main specifications of 48” roller testing platform (AVL Zửllner GMBH) are shown in Table 4. During the test, the vehicle speed - v (km/h), the pulling power of the roller P (kW), the pulling force of the roller F (N) are determined directly from the roller test platform. Other parameters such as the external torque exerting on the active wheel - M (Nm), the angular acceleration of the active wheel -e (m/s2) are determined indirectly from the measurement parameters ( F , v ) of the platform. Inertia moment of total empirical measurement is determined by the formula, [3]: Where: M t , M g , e t , e g - the external torque and the active wheel angular acceleration when the roller accelerates and decelerates. Figure 2. General layout of Chassis Dynamometer at Light Duty Test Cell-NETC Table 4. Main specifications of 48 roller test platform, [7] No Specifications Unit Value 1 Maximum weight of active bridge kg 4500 2 Test vehicle weight kg 454ữ5448 3 Inertial mass of 2 rollers kg 1678 4 Maximum acceleration m/s2 5,3 5 Maximum pulling force N 5870 6 Maximum test speed km/h 200 3.2.2. The order of conducting experiments To determine the inertia moment, the roller test platform is controlled to operate in a “passive” mode (using the roller of the testing platform to turn the vehicle’s active wheel), the engine does not start, the clutch is in the state closed, and the position of the gear varies from 1 to 5. In each hand, use the rollers of the testing platform to pull the wheel to actively accelerate to the speed max 3 v , and then disconnect the power to the rollers to let the wheel actively decelerate to 0 km/h. 3.2.3. Experimental results After determining the external torque values and acceleration of the active wheel angle, proceed to select the values M t , M g , e t , e g at the time that the active wheel angular velocity when accelerating and decelerating is equal [3]. The empirical results determine the values M t , M g , e t , e g corresponding to the transmissions are presented in Table 5. t gTN t g M MI e e - = + (6) NGHIấN CỨU KHOA HỌC 58 Tạp chớ Nghiờn cứu khoa học, Trường Đại học Sao Đỏ, ISSN 1859-4190, Số 1 (68) 2020 Table 5. Experimental results to determine M t , M g , e t , e g No Parameter Unit Gear 1Gear 2Gear 3Gear 4Gear 5 1 External torque, when accelerating, M t Nm 3,478 853 332 195 166,6 2 External torque, when decelerating, M g Nm 8,9 1,58 2,47 4,71 6,97 3 Acceleration of wheel angle when accelerating et rad/ s2 8,602 7,61 6,97 4,76 4,3 4 Acceleration of wheel angle when slowing down, e g rad/ s2 8,601 7,62 6,98 4,81 4,28 The value of the total and rotating mass coefficient determined by empirical method is shown in Table 6. Table 6. Inertia moment of total and rotating mass coefficient determined by experiment No Parameter Unit Gear 1 Gear 2Gear 3Gear 4Gear 5 1 Total inertia moment, I TN kg.m2 201,64 56,01 23,64 19,84 18,6 2 Rotation mass coefficient, γ mTN 1,71 1,196 1,083 1,069 1,065 4. COMMENTS In Table 7 presents the results of determining inertia moment, rotation mass coefficient with 3 cases: Calculating based on empirical formula (1); Theoretical calculations (Table 3) and experimentally on roller test platforms (Table 6). We see: Table 7. Summary of the results of determining inertia moment and rotation mass coefficient on 3 alternatives No Parameter Unit Gear 1 Gear 2 Gear 3 Gear 4 Gear 5 1 Total inertia moment (experimental), I TN kg.m2 201,64 56,01 23,64 19,84 18,6 2 Total inertia moment (theoretical), I LT kg.m2 198,11 55,62 23,61 19,23 18,4 Compare I LT to I TN % 1,75 0,7 0,13 3,07 1,08 No Parameter Unit Gear 1 Gear 2 Gear 3 Gear 4 Gear 5 3 Total inertia moment total (experience), I KN kg.m2 191.45 61.03 28.57 20.75 16.85 Compare to I KN I T % 5,05 8,96 20,85 4,59 9,41 4 Rotation mass coefficient (theoretical), γ mTN 1,71 1,196 1,083 1,069 1,065 5 Rotation mass coefficient (theoretical), γ mLT 1,70 1,194 1,082 1,067 1,064 Compare γmLT to γmTN % 0,58 0,17 0,09 0,19 0,09 6 Rotation mass coefficient (experience), γ mLT 1,67 1,21 1,1 1,07 1,06 Compare γ mTN to γmTN % 2,34 1,17 1,66 0,09 0,47 - The value of inertia moment and rotation mass coefficient tends to decrease when moving to a higher gear. - At gear 1, the inertia moment and rotation mass coefficient spin a lot bigger than at gear 5 in all 3 options. - Rotation mass coefficient when determined experimentally has difference value when determined by theory. Specifically, the errors in turn are 0,58%, 0,17%, 0,09%, 0,19%, and 0,09% at gears: 1, 2, 3, 4 and 5. The cause of this error is mainly due to the theoretical calculation ignoring the compression pressure values in the engine cylinder, but when experimented, the engine cylinder still has the compression pressure (not burning). In addition, ignoring other factors such as auxiliary parts of rotation in the engine, wheel slip to the road surface, tire pressure,... - Rotation mass coefficient when determined experimentally has a different value from the empirical formula. Specifically, the errors are respectively 2,34%, 1,17%, 1,66%, 0,09%, 0,47% at gears: 1, 2, 3, 4, and 5. The main cause of errors is due to the fact that when determining by empirical formula, only the transmission ratio of the powertrain is concerned, not the structural characteristics of each vehicle. LIấN NGÀNH CƠ KHÍ - ĐỘNG LỰC 59Tạp chớ Nghiờn cứu khoa học, Trường Đại học Sao Đỏ, ISSN 1859-4190, Số 1 (68) 2020 5. CONCLUSION The paper has identified the total inertia moment and rotation mass coefficient of Hyundai Starex CVX by theory (on the basis of using Inventor software) and experiment (on roller test platform), corresponding to each transmission number of the gearbox. The detailed value of inertia moment of parts and rotation mass coefficient calculated by Inventor software has high accuracy and will be used as input parameters for Hyundai Starex’s linear motion simulation software such as GT-Drive, Matlab Simulink. REFERENCES [1] J.Y,Wong (2008), Theory of ground vehicles, John Wiley &Sons, Inc. [2] Thomas D. Gillespie (2014), Fundamentals of Vehicle Dynamics, Society of Automotive Engineers Inc. [3] Xerghờiev L.V (1990), Lý thuyết xe tĕng (Tài liệu dịch), Học viện KTQS. [4] Nguyễn Đỡnh Tuấn, Phạm Trung Kiờn, Nguyễn Hoàng Vũ (2012), Phỏt triển mụ hỡnh mụ phỏng động lực học chuyển động thẳng của xe tĕng trong Matlab/Simulink/ SimDriveline, Khoa học và Kỹ thuật, Học viện Kỹ thuật Quõn sự. [5] Nguyễn Hoàng Vũ (2014), Thuyết minh đề tài NCKH & PTCN cấp Quốc gia “Nghiờn cứu chế tạo thử nghiệm ECU phự hợp cho việc sử dụng nhiờn liệu diesel sinh học với cỏc mức pha trộn khỏc nhau”, mó số ĐT.08.14/ NLSH, thuộc Đề ỏn phỏt triển nhiờn liệu sinh học đến nĕm 2015, tầm nhỡn đến nĕm 2025. [6] Nguyễn Hoàng Vũ (20120), Bỏo cỏo tổng kết đề tài NCKH & PTCN cấp Quốc gia “Nghiờn cứu sử dụng nhiờn liệu diesel sinh học (B10 và B20) cho phương tiện cơ giới quõn sự”, mó số ĐT.06.12/NLSH, thuộc Đề ỏn phỏt triển nhiờn liệu sinh học đến nĕm 2015, tầm nhỡn đến nĕm 2025. [7] AVL Zửllner GMBH, Chassis Dynamometer System for Exhaust Emission Analysis. [8] Raffaele Di Martino (2005), Modelling and Simulation of the Dynamic Behaviour of the Automobile, PhD thesis in Mechanical Engineering, University of Salerno. [9] Aleksander UBYSZ (2010), Problems of rotational mass in passenger vehicles, Department of Vehicle Construction, Faculty of Transport, Silesian Technical University, Poland. [10] GT-SUITE (2011), Vehicle Driveline and HEV tutorial, Gamma Technologies, Inc. [11] Matlab&Simulink, SimDriveline™ User’s Guide, The Mathwork, Inc, 2010. [12] Lờ Vĕn Tụy (2012), Thử nghiệm và mụ phỏng ụ tụ trờn bệ thử động lực học, Đại học Bỏch khoa Đà Nẵng. [13] [14] Hyundai Motor Company, Technical Specifications for H1 – Bus NGHIấN CỨU KHOA HỌC 60 Tạp chớ Nghiờn cứu khoa học, Trường Đại học Sao Đỏ, ISSN 1859-4190, Số 1 (68) 2020 THễNG TIN TÁC GIẢ Vu Thanh Trung - Summary of training and research process (time of graduation and training and research program): + 2006: Graduated from University with a major in Dynamic Mechanical Engineering + 2011: Graduated Master degree in Automotive Engineering - Summary of current Job: Lecturer, Faculty of Automotive, Sao Do University - Areas of interest: Automotive dynamics; new energy, alternative fuel in vehicle; Control engineering application for automotive systems. - Email: vuthanhtrung286@gmail.com - Phone: 0968567683 Ngo Thi My Binh - Summary of training and research process (time of graduation and training and research program): + 2006: Graduated from University with English major + 2010: Graduated Master of English major - Summary of current job (positions, offices): Lecturer, Department of Tourism and Foreign Languages, Sao Do University - Areas of interest: Basic English, English for Automotive Engineering Technology, English for Business and Tourism. - Email: tienganhmybinhsd@gmail.com - Phone. 0984188873