吉林大学机械学院本科毕业设计外文翻译格式.doc

吉林大学本科毕业论文外文翻译本科生毕业设计（论文）翻译资料中文题目： 配合新一代液力变矩器的柴油动力线的一些特性 英文题目：some properties of a diesel driveline with hydrodynamic torque converters of thelastest generation学生姓名： 学 号： 班 级： 专 业：机械工程及自动化指导教师： Some properties of a diesel drive line with hydrodynamic torque converters of the latest generationAbstractDynamic properties of a drive line with a controlled Diesel engine, hydrodynamic transmission mechanism, additional gearing and a loading-working machine producing common monoharmonic loading are investigated. Solution of the dynamic problem is based on phenomenological experimental data: driving torque-speed characteristic in the part of the prime mover and so-called external static characteristic in the hydrotransmission part. The non-linear task is solved by a modified harmonic balance method that was described in preceding publications by the author. Keywords: Machine drive line; Controlled Diesel drive; Hydrodynamic torque converter; Working machine; Periodic loading; Stationary dynamic state Nomenclature and abbreviationsa, b - -Coulomb and viscous non-dimensional friction losses Ai, Bi - -coefficients in mathematical expression of torque-speed characteristic i, im -kinematic transmission, supplementary gearing transmission ratio I, Iz -mean reduced moment of inertia in driving and loading part k, kK -tangent slopes of (i) and K(i) curves respectively K -moment transmission M -Diesel-engine moment MD(,z) -controlled torque-speed driving characteristic MDmax(), MDmin() -torque-speed characteristic for maximal and minimal fuel supply M1, (), M2, () -pump loading moment and turbine driving moment MT1, MT2 -friction loss moment in driving and loading part Mz, Mza -mean value and amplitude of loading moment -hydrodynamic converter characteristic radius t -time T, TD-Watt regulator and Diesel-engine time constant u, z -gas lever and regulator displacement w -common dynamic variable -regulator structural parameter -regulator damping ratio -coefficient of rotation moment -loading angular velocity , -index denoting mean value and periodical component -hydraulic medium density -rotation angle 1, (), 2 -pump and turbine angular velocity DM -Diesel-engineG, GD -additional and Watt-regulator gearing HdPT -hydrodynamic power transmission IJ -InjectorLM -loading mechanism (working machine) P, R, T-pump, reactor, turbineArticle OutlineNomenclature 1. Introduction 2. Mathematical model of the system 3. Stationary dynamic solution at monoharmonic loading4. Results evaluation and concluding remarks 1. IntroductionDynamic properties of a drive line (actuating unit) consisting of a controlled Diesel engine (DM), hydrodynamic power transmission system (HdPT), additional gearing (G) and a loading mechanism (LM) or working machine are investigated. The working machine loads the prime mover and the transmissions with a prescribed moment. A simple idealised schematic layout of the complete system is given in Fig. 1. The considered Diesel engine is a standard production: ZETOR 8002.1 controlled by a mechanical (Watts) or electronic regulator RD governing fuel injector IJ. In the place of the hydrodynamic power transmission there are gradually applied hydrodynamic torque converters of the latest generation that have been projected and tested in WUSAM (Research and Projecting Institute of Machines and Mechanisms), j.s.c. Zvolen, Slovakia. These converters represent a three component assembly composed of a rotational pump (P), turbine (T) and a reactor (R) that may revolve in one direction as a free wheel. Advantage of these converters is the fact that their external dimensions and the dimensions of their individual components are identical and they may be mutually changed and arbitrarily combined in order to reach demanded properties. They differ only by internal configuration and blade geometry. According to 1 up to now more than 70 various types have been experimentally tested and from them the ones have been chosen that optimally fulfilled required properties. The mechanical system under consideration represents a sophisticated energy transfer chain from a sourceprime mover to working mechanism. Because every real drive is of finite power, any periodic loading always evokes vibrations of all the dynamic variables even though we suppose all the connecting shafts and gearings rigid and backlash free. The influence of dynamic loading on the prime mover may be just controlled by a suitable choice of the torque converter. Fig. 1.Schematic layout of the Diesel drive line.In the paper influence of constant and periodic loading on time course of all the dynamic variables of the system (and particularly on the variables of the prime mover) is investigated at application of some selected types of hydrodynamic torque converters of the latest generation. For fulfilling this task it is necessary to create a suitable mathematical model of the whole combined system and then find its stationary solution corresponding to a required loading. 2. Mathematical model of the systemAt the beginning it is necessary to emphasize that mathematical modelling of the drive line in question is based, in our approach, on knowledge of the published phenomenological data: stationary torque-speed characteristic of the prime mover and so-called external static characteristic of the applied hydrodynamic torque converter. It is a much simpler process than modelling based on thermodynamic equations of burning fuel mixture in the Diesel engine and on hydrodynamic equations of real streaming working medium in very complicated cavities of the torque converter. The characteristics are usually given by manufacturer of the individual system components. This is different and simpler approach to solution of the problem than one may find e.g. at Ishihara 2, Hrovat and Tobler 3, Kesy and Kesy 4, Laptev 5 and some others. The derived dimensional and non-dimensional mathematical models of the mechanical system are introduced in 6. The non-dimensional, reduced, so-called single-shaft model (in the driving and loading part), was derived in the form of combined system of the following differential and algebraic equations:(1)(2)(3)(4)M2=KM1,(5)=(i),(6)K=K(i),(7)(8)(9)where the meaning of the individual symbols is explained in nomenclature. In the non-dimensional model all the dynamic variables and parameters are expressed by means of properly chosen relative standard quantities so that the model of the system might be the most simple. Transformation of the original equations system to the non-dimensional form Figs. (1), (2), (3), (4), (5), (6), (7), (8) and (9) is described in detail in 6. As for this cited paper, it is necessary to say that the relative standard value of loading angular frequency has been settled according to the relation , where in denominator is relative standard value of time. For this value, the time constant of the regulator has been just chosen, i.e. , where the related dimensional dynamic variables are distinguished by upper bars. The introduced mathematical model has nine variables: M, M1, 1, z, , K, i, M2, 2 and their meaning is explained in nomenclature. The first three equations represent mathematic model of the prime mover where in inertia moment I there is included inertia moment of the pump and equivalent part of the working medium because driving and pump shafts are connected by a rigid clutch. The right side of Eq. (3) represents the controlled stationary torque-speed characteristic for which it holds:MD(1,z)=MDmax(1)-MDmax(1)-MDmin(1)z,(10)where MDmax(1), MDmin(1) represent its non-dimensional extreme branches for maximal and minimal fuel supply and z is the non-dimensional regulator deviation. If the experimentally measured dependences MDmax(1), MDmin(1) are expressed by second degree polynomials then the controlled non-dimensional torque-speed characteristic has the form:(11)From the introduced model it is evident that at chosen parameter value u driving speed growth causes regulator displacement to increase and fuel supply to decrease. The idealised controlled torque-speed characteristic for a chosen parameter value u (gas lever displacement) is schematically depicted in Fig. 2. From Eq. (2) it is evident that the structural parameter must be chosen in such away that regulator self-oscillations should not occur. Eqs. Figs. (4), (5), (6), (7) and (8), in the sense of considerations in 6, represent the dynamic equations of the torque converter. Eq. (9) represents simplified motion equation of the loading mechanism under assumption that the reduced inertia moment Iz does not depend on rotation angle . In this reduced inertia moment there is involved inertia moment of the turbine with equivalent part of the working medium too. It is obvious that in this inertia moment and in all moments of the loading mechanism there is considered gear ratio im of the supplementary gearing of the originally non-reduced system. Eqs. Figs. (6) and (7) represent the external static characteristic of the hydrodynamic transmission, i.e. formal dependences of and K on the kinematic ratio i and the dependences are given for every converter type in graphical form. The dynamic variables and K are defined in non-dimensional form very simply by non-linear relations Figs. (4) and (5). In a general way these non-dimensional variables are defined by means of dimensional values (distinguished by upper bars) as follows:(12)where individual symbol meaning may be found in nomenclature. As we have chosen (according to Fig. 2) for the relative standard value of angular velocity the idle motion angular velocity of the Diesel engine at maximal fuel supply, i.e. at z=0, then from Figs. (4) and (12) it is evident that the relative standard moment value is(13)It means that if for the applied drive s1 and all the applied converter types have equal characteristic radius m and if we consider mean value kgm3 at stationary thermic regime then the relative standard value of the moment is Nm for all the considered converter types. The external static characteristics of the applied converters with internal labelling: M350.222, M350.623M, M350.675, M350.72M3M, are (according to the measuring records 7) successively introduced in Fig. 3(a)(d). When the torque-speed characteristic is known and the measured dependences Figs. (6) and (7) are at disposal, it is possible to solve the combined system of differential and algebraic equations Figs. (1), (2), (3), (4), (5), (6), (7), (8) and (9). This is a little complicated task because the differential and algebraic equations in the accepted mathematical model are non-linear. Stationary dynamic state of the system was calculated by a modified harmonic balance method that is fully described in 8. Fig. 2.Idealised diagram of the driving torque-speed characteristic.Fig. 3.External static characteristics of the hydrodynamic power transmissions: M350.222, M350.623M, M350.675, M350.72M3M.3. Stationary dynamic solution at monoharmonic loadingIn this section stationary solution of the system Figs. (1), (2), (3), (4), (5), (6), (7), (8) and (9) will be looked for always with the same prime mover and successively considering all the converters types whose external static characteristics are introduced in Fig. 3(a)(d). If each of the nine dynamic variables is denoted by a common symbol wM, M1, 1, z, , K, i, M2, 2 then, in accordance with applied method, every dynamic variable may be formally expressed as a sum of its mean and its centred periodic component, i.e.:w=w+w.(14)Following the mentioned method, on restrictive presumption that it holds:MzaMzww,(15)the system Figs. (1), (2), (3), (4), (5), (6), (7), (8) and (9) splits into two independent systems of equations: a system of non-linear algebraic equations for calculation w and a combined system of linearised differential and algebraic equations for calculation w. If one considers that friction losses in the driving part are implicitly expressed already in the torque-speed characteristic of the drive and in the external static characteristic of the applied hydrodynamic torque converter and friction losses in the loading part are supposed as a combination of Coulomb and viscous friction, i.e.:MT2=a+b2,(16)then the non-linear algebraic system has the form:(17)The combined system of the linearised differential and algebraic equations is(18)where for writing abbreviation it is denoted:(19)The solution process of both equation systems Figs. (17) and (18) is introduced in 8. The system of non-linear equations (17) was calculated for three parameter levels u (u=0.3,0.4,0.6) that respond to 30%, 40%, and 60% of the maximal gas lever displacement. To each chosen parameter value u, a certain driving angular velocity interval responds. From Fig. 2 and from Eq. (2) it is evident that for a chosen value u the corresponding mean driving angular velocity value must lie in interval:1a11b,(20)where for border values of the interval it holds:(21)For the chosen parameter value u=0.3 and for different mean values Mz, the calculated mean values w (for the drive line with given drive and all the considered converter types) are introduced in diagrams in Fig. 4(a)(d). Analogical mean values w of the same variables corresponding with the parameter u=0.4 are in Fig. 5(a)(d). Finally, the calculated mean values w corresponding with parameter u=0.6 and identical torque converter types are depicted in Fig. 6(a)(d). Here it is important to remind that x-coordinates in Fig. 4, Fig. 5 and Fig. 6 represent the mean angular velocity interval (20) gradually for parameters u=0.3,0.4,0.6 and the decimal fractions on this section denote only its decimal division. From the calculated mean values w in Fig. 4, Fig. 5 and Fig. 6 and from the introduced external static characteristics in Fig. 3a complete nine of the mean values w can be determined for any mean loading value Mz and estimated loss moment value MT2 in the loading part. When this complete nine w is known then it is possible, in the sense of the applied method, to construct all the constant coefficients of the combined differential and algebraic system (18) for calculation w. This system is already linear and may be solved by known classical methods. First of all, we take interest in stationary dynamic solution. In sense of the procedure one may express the centred periodic component of every dynamic variable in the form:w=Mza(Wccost+Wssint),(22)where notations Wc, Ws represent cosine and sine components of the dynamic factor (transmissibility) of corresponding dynamic variable. Detailed computing procedure is introduced in 8. For transmissibility of the centred periodic component of every dynamic variable it holds:(23)As an example in Fig. 7, Fig. 8, Fig. 9, Fig. 10 and Fig. 11 there are successively introduced dynamic characteristics of the centred periodic components of dynamic variables: moment (M) and angular velocity of the drive (1), loading moment of the pump (M1), moment (M2) and angular velocity of the turbine (2) for the system with hydrodynamic converter M350.222 and for chosen parameter value u=0.4. Results are given in two forms of dynamic characteristics, namely as classic frequency response functions (upper parts) and as Nyquist diagrams (lower parts). Both types of dynamic characteristics are calculated for four values of the loading mechanism inertia moment: kgm2 and for supplementary gear ratio im=1. Equal sections of loading angular velocity with value corresponding to equal sections on frequency response function x-coordinates are in the Nyquist diagrams separated by bold points as well. In dynamic calculations, the Diesel-engine time constant s, regulator time constant s and the regulator damping ratio =0.55 were considered. The left parts of the dynamic characteristics in Fig. 7, Fig. 8, Fig. 9, Fig. 10 and Fig. 11 correspond to the dynamic regime with mean values: =0.111, K=3.12,i=0.127, which are quantified by bold points on the left thin vertical in the external static characteristic in Fig. 3(a), when the converter works in so-called friction clutch regime. Mean values of dynamic variables, corresponding to this dynamic regime, are: M=0.0506, M2=0.158, 1=0.673, 2=0.0855, Mz=0.152, z=0.0849. These values are also accentuated in Fig. 5(a) by bold points on thin vertical line. In this dynamic regime the converter works with mean transfer energy efficiency 0.405. The right parts of the dynamic characteristics introduced in Fig. 7, Fig. 8, Fig. 9, Fig. 10 and Fig. 11 correspond to dynamic regime with mean values: =0.111,K=1.1, i=0.74, represented by bold points on the right thin vertical on the external static characteristic in Fig. 3(a) when the converter works in so-called moment converter regime with mean energy transfer efficiency higher than 0.8. The mean values of dynamic variables corresponding to this dynamic state are: M=0.0506, M2=0.0557, 1=0.673, 2=0.4986, Mz=0.0466, z=0.0849 and are marked out in Fig. 5(a) as well on thin vertical line by bold points. Non-dimensional friction losses at dynamic calculation were considered according to (16) as follows: , , where is dimensional relative moment standard value (13). Fig. 4.Mean values of the chosen dynamic variables w of the system with convert