具有車架結(jié)構(gòu)車輛的怠速震動分析外文文獻(xiàn)翻譯、中英文翻譯

1、附錄附錄A 外文文獻(xiàn)原文An Analysis of Idling Vibration for a Frame Structured VehicleABSTRACTA finite element model for an entire frame-structured sports utility vehicle was made to evaluate the characteristics of the idling vibrations for the vehicle. The engine exciting forces were determined by Soumas metho

2、d to simulate the idling vibrations. The modeling of the power plant and the entire vehicle was verified by the reasonable agreement of the experiment and calculation results. Attention was focused on the frequency of the first-order vertical bending mode for the frame. It has become clear that the

3、idling vibration level of the vehicle is lowered by decreasing the frequency of the first-order frame bending mode.INTRODUCTION One of the defects of a diesel vehicle, which has fuel and economical efficiency, is idling vibration for a vehicle body. In a diesel engine, sharp pressure rise caused by

4、the generation of the thermal energy affects the pistons. In the crank system, which converts the linear motion into the rotary motion, two types of reaction forces excite the engine block: the reaction caused by the alternation of the velocity vector in each moving parts, and by the non-uniform rot

5、ary motion generated by the finite number of cylinders. The forces transmit to an engine block, an engine foot, a rubber engine mount, a frame, a rubber cab-mount, and then a vehicle body, which make occupants uncomfortable. The idling vibration for large-sized commercial vehicles was estimated at t

6、he early development stage, and the measures against the vibration were taken by simulating the engine exciting forces with Soumas method,and entering them to a vehicle model. In this paper, the idling vibration was determined by entering the engine exciting forces to the vehicle model, which was ma

7、de of the finite element of the frame and the body for a small-sized recreational vehicle (RV). Also in this paper, how the natural modes for the frame changes in the vehicle condition is analyzed, and it was indicated that the natural frequency of the first-order vertical bending for the frame had

8、a significant effect.ANALYSIS OF THE VEHICLE BODY VIBRATIONFigure 1 shows the results of analyzing the frequencies of the acceleration in vertical vibration generated on the seat rail while idling in small-sized RV powered by 4-cylinder diesel engine. The main part of the idling vibration is the sec

9、ond-order engine rotation. The 0.5th, 1st, and 1.5th -orders are also critical. However, these orders are caused by the varied combustion between cylinders. A measure against the varied combustion can be expected by improving the injection system. In this research, only 24Hz of the second-order at t

10、he idling rotation speed of 720rpm is focused on as a measure in the vehicle structure. Besides, a measure for lowering the vibration is studied because the vertical vibration on seats has a great damaging effect on human sense.IDENTIFICATION OF THE ENGINE EXCITING FORCEThere are three paths for the

11、 engine to excite vibration to a vehicle body: through an engine mount, a driving system, and a tail pipe. In this paper, the path through an engine mount, which has a greatest effect, is studied. The various types of methods to identify the exciting force through an engine mount are known. In this

12、paper, Soumas method is used.OUTLINE OF SOUMAS METHODThe cause of the exciting force to an engine block in the controversial frequency domain of the idling vibration is considered. First, the combustion pressure that acts on the pistons is considered to cause the vibration. However, assuming that a

13、piston crankshaft does not move with a flywheel and an engine block fixed in some way, the engine components are supposed to be completely rigid in this frequency domain. In this situation, the engine block will not vibrate if the piston crankshaft does not move in spite of the rapid pressure rise i

14、n a combustion chamber due to the diesel combustion.Accordingly, the direct cause of the engine block vibration is not the combustion pressure but the reaction against the piston crankshaft movement. To determine the exciting force to the engine block, the reaction forces against the movement of the

15、 mass (mainly in crank system and piston system), which works inside and outside of the engine block, may be calculated.In Soumas method, the non-uniform rotary motion in the crank system is found by measuring the pulse generated in a ring gear of the flywheel. Then, the vertical motion in the conne

16、cted piston system is calculated to determine the exciting force to the engine block using each mass specification value.VERIFICATION OF THE ACCURACY IN THE EXCITING FORCEThe exciting forces are added at the point corresponding to the crankshaft on the entire vehicle model (described later). The vib

17、ration on the head cover and the right engine foot, which the exciting forces mostly affect, is estimated. The results of comparing the calculation with the experiment are shown in Figure 2 and 3. In Figure 2 and 3, 5 types of calculated results are shown considering the idling rotation speed change

18、s.In Figure 2 and 3, the calculation and the experiment are identified around 24 Hz, 48 Hz, and 72 Hz of 2nd, 4th, and 6th-orders at the speed of 720 rpm. The data of the left engine foot, which is not shown in this paper, is also almost identified. In this frequency domain, as for the vibration, th

19、e engine and the vehicle body are insulated by the engine mount. The body hardly affects the engine vibration. As the data of the experiment and the calculation is identified in this domain, the power plant modeling and the exciting force can be considered reasonable.However, around 12 Hz of 1st-ord

20、ers, data is not much identified. In this frequency domain, the vibration of the engine and the vehicle body are mutually coupled through the engine mount. Therefore, the accuracy of the vehicle body model has a damaging effect.IMPROVEMENT OF THE MEASURING ACCURACY IN LOW-FREQUENCY VIBRATIONThe engi

21、ne exciting force was determined using Soumas method, and the vibration in each part of the engine was calculated by adding the exciting force. So far, however, the calculated data has not been much identified with the actual measurement. Therefore, the accuracy of the actual measurement is improved

22、. In the surface vibration of the engine, the low-frequency vibration, which causes the idling vibration, and the high-frequency vibration, which causes noise, are mixed. When the mixed vibration is measured with a piezo element acceleration pickup, the high-frequency order is emphasized and the tar

23、get low-frequency order becomes relatively small. For example, the measured acceleration to time waveform for the vertical vibration in the right engine foot is shown in Figure 4. In this paper, a strain gage acceleration pickup, which measures force acting on the inner weight by strain, is used. Th

24、is device, which is larger than a piezo element acceleration pickup, is more sensitive to the acceleration. Besides, silicon oil is filled inside to protect the detecting parts in this device, which mechanically blocks off the high-frequency order. The measured acceleration to time waveform for the

25、vertical vibration with the device is shown in Figure 5. Compared with Figure 4, Figure 5 shows only the low-frequency order although the same area was measured. In this way, the high-frequency order is blocked off, which results in the higher sensitivity with the device. This time, the device, whic

26、h measures the acceleration ranging from 0 to 20m/s2,was used. This device is easily calibrated using G-forces because it has the higher sensitivity. When a piezo element acceleration pickup was used, the differences between the calculation and the experiment were 20-40% in the main order of the vib

27、ration, and a few times in other orders. Therefore, the principle of Soumas method using a piezo element acceleration pickup has been in doubt. However, the data of the experiment and the calculation has been identified as shown in Figure 2 and 3 since a strain gage acceleration pickup, which has be

28、en used in the experiment of movement performance, was used for an engine.Fig. 1 Seat rail vertical vibration Fig. 2 Head cover lateral vibrationFig. 3 Right engine foot vertical vibration Fig.4 Measurement with piezo element acceleration pickupENTIRE VEHICLE MODELFigure 6 shows the body model. Inte

29、rior and exterior equipments such as doors and seat are added in the form of 85 mass points to the main structure modeling detailed with sheet metal finite elements. The grid points are 61,912. Figure 7 shows the model where a frame, a suspension, and an engine are combined, and a fuel tank and a bu

30、mper is added in the form of concentrated mass. The grid points are 39,262.Combining the models shown in Figure 6 and 7 using cabmount makes the entire vehicle model. Total grid points mounts to 101,174. The calculation time is 3,293 seconds using IBMSP2, MSC/NASTRAN Version 70.5.2. The calculating

31、method is package calculation. If the model becomes on larger scale, the model must be calculated by the block structure.Figure 8 shows the frequency response function, indicating the responses of the frame with the right back engine mount after exciting the drivers seat rail. In the frequency rangi

32、ng from 20 to 30 Hz, which is required for the analysis, the data of the experiment is qualitatively identified with that of the calculation.Fig. 5 Measurement with strain gage acceleration pickup Fig. 6 Body modeFig.7 Frame,power plant and suspension model Fig.8 Frequency response functionCORRELATI

33、ON ANALYSIS OF THE MODESFrom the viewpoint of vibration characteristics, it can be considered that an entire vehicle is insulated by the engine mount and the cabmount, which have relatively small spring constants, although the insulation is not complete. When the entire vehicle is divided into block

34、 structures by each insulating mount and suspension, the body has 4 block structures:(1) Block where interior equipment is added in the form of concentrated mass to the body as shown in Figure 6, which is described as “body”, hereafter.(2) Block where the fuel tank and the bumper are added in the fr

35、om of concentrated mass to the frame as shown in Figure 7, which is described as “frame,” hereafter. (3) Power plant (4) SuspensionAmong the above block structures, (1) body and (2) frame have the natural frequency around 24 Hz in the idling vibration. The vibration characteristics for the body, the

36、 frame and the entire vehicle model are compared and investigated.COMPARISON OF NATURAL FREQUENCYFigure 9 shows the distribution of the natural vibration frequency in each block structure and in the vehicle condition. The frame has 17 natural modes below 50Hz. In Figure 7, the model mounting a power

37、 plant and a suspension on the frame, is called Y chassis, which has 35 natural modes below 50 Hz. Y chassis makes the entire vehicle model by mounting the body, which has 94 natural modes below 50 Hz.When the number of natural modes of Y chassis is added to 61 natural modes of the body, total numbe

38、r of the modes amounts to 96. The number of the natural modes of the entire vehicle model (94) is less than the above total number by 2 modes. This is because 2 natural modes became above 50 Hz by combining Y chassis and the body, as the result of analyzing the mode correlation described later.Fig.

39、9 Natural modes in frequency domain附錄B 外文文獻(xiàn)中文翻譯具有車架結(jié)構(gòu)車輛的怠速震動分析摘要建立全車架結(jié)構(gòu)SUV的有限元模型，用來評價車輛的怠速震動特性。用Souma理論確定發(fā)動機的動力來模擬怠速震動。發(fā)動機和整車的模型通過實驗和計算結(jié)果協(xié)調(diào)以后共同決定。注意力放在了車架一階縱向彎曲模型的頻率上。降低一階車架彎曲模型的頻率可以減少車輛的怠速震動已經(jīng)變得明確。簡介具有燃油經(jīng)濟性的柴油車的一個缺點就是車身的怠速震動。在柴油發(fā)動機里，由熱能積聚引起的壓力急劇上升會影響活塞。在把直線運動轉(zhuǎn)換成旋轉(zhuǎn)運動的曲軸系統(tǒng)里，有兩種反作用力使得發(fā)動機體振動：由移動部件運動換向引

40、起的反作用力，和有限的氣缸不均勻的轉(zhuǎn)動引起的。這個力傳遞到發(fā)動機機體，發(fā)動機底部，橡膠的發(fā)動機支座，車架，橡膠駕駛室支架，最后到車身，引起乘客不舒服。大型商用車的怠速震動的平復(fù)處于發(fā)展的初期，用Souma理論模擬發(fā)動機震動，然后建立模型。這篇論文中，將發(fā)動機置于車中來確定怠速震動，因為車架和車身的有限元被當(dāng)做一個小型休閑車。另外，在這篇文章中，也分析了車輛車架自然模式如何改變，并且指出車架一階縱向彎曲的自然頻率具有重要的影響。車身震動的分析圖A1顯示了四缸柴油機RV怠速過程中座椅扶手處采集的加速過程中縱向震動頻率的分析。怠速震動的主要部分是二階發(fā)動機轉(zhuǎn)動，第0.5，第1，和第1.5階同樣重要。

41、但是，這些不同是由于不同氣缸的燃燒不同而引起的。完善噴射系統(tǒng)可以解決燃燒的差異。在這個實驗中，只集中研究怠速轉(zhuǎn)速是720rmp時24Hz車架的二階震動。此外，也研究了降低振動的措施，因為座椅的縱向振動對人類的感覺有很大的破壞性影響。發(fā)動機引起作用力的判定發(fā)動機將振動傳遞給車身的路線有三種：通過發(fā)動機支座，驅(qū)動系統(tǒng)，和尾氣排放管。在這篇論文中，研究了起主要作用的發(fā)動機支座的路線。研究方法有很多種，這里用Souma理論。Souma理論的概要考慮引起發(fā)動機集體受力的有爭議的怠速振動頻率范圍。首先，作用在活塞上的燃燒壓力被認(rèn)為引起這個振動。但是，假設(shè)活塞曲軸并不隨飛輪移動并且機體以某種方式固定，在這個

42、頻率范圍發(fā)動機的零件被認(rèn)為是完全剛性的。在這種情況下，如果活塞曲軸不移動，發(fā)動機機體就不會振動，盡管柴油燃燒引起壓力的迅速上升。相應(yīng)地，引起發(fā)動機機體振動的直接原因不是燃燒壓力，而是活塞曲軸運動的反作用力。為了確定作用在發(fā)動機機體上的這個力，需要計算在機體內(nèi)外都發(fā)揮作用的反作用力。在Souma理論里，通過測量在飛輪齒圈上收集到的脈沖來發(fā)現(xiàn)曲軸系統(tǒng)的不協(xié)調(diào)旋轉(zhuǎn)運動。然后計算相連的活塞系統(tǒng)的縱向運動來確定發(fā)動機機體上的作用力。作用力準(zhǔn)確性的驗證在整車模型里（后續(xù)描述），振動力的增加和曲軸是對應(yīng)的。評估振動主要影響的引擎蓋和發(fā)動機右側(cè)底部。計算數(shù)據(jù)和實驗結(jié)果的比較結(jié)論在圖A2和圖A3中表示了出來。在圖A2和圖A3中，表示出來5種不同的計算結(jié)果，因為要考慮怠速轉(zhuǎn)速的變化。在圖A2和圖A3中，鑒定了在轉(zhuǎn)速為720rpm時第二第四和第六階的24Hz，48Hz和72Hz的計算數(shù)據(jù)和實驗結(jié)果。發(fā)動機左側(cè)底部的數(shù)據(jù)，在這篇論文中沒有顯示出來，但是也幾乎全部鑒定了出來。至于在這個頻率范圍內(nèi)，發(fā)動機和車身的振動被發(fā)動機支座隔離開來。車身幾乎影響不到發(fā)動機的振動。因為實驗數(shù)據(jù)和計算結(jié)果的鑒定是在這一范圍