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1
Al-Sabeeh, A. K. "Double Crank External Geneva Mechanism". Journal of Mechanical Design 115, nr 3 (1.09.1993): 666–70. http://dx.doi.org/10.1115/1.2919242.
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A designer specified motion characteristics can be obtained using the double crank external Geneva mechanism presented in this work. This mechanism basically consists of double cranks and double curved slots that work together in generating the desired output motion. In other words, the profiles of the slots are defined based on the specified output motion. This feature opens the door for big motion improvements, such as minimizing the maximum acceleration and eliminating infinite jerk. Furthermore, it allows for stepping angles larger than 120 deg (the upper limit for simple Geneva mechanism) and even operates at smaller overall pressure angle. In this paper, the equations defining the slot profiles for some desired output motion are derived. The expression for the pressure angle as a function of the crank displacement angle is obtained. The equations are put into application by an example design of double slotted replacement Geneva mechanism, showing the applicability of the approach and the improvement gained in reducing the pressure angle.
2
Rankin, Jeffery W., i Richard R. Neptune. "The Influence of Seat Configuration on Maximal Average Crank Power during Pedaling: A Simulation Study". Journal of Applied Biomechanics 26, nr 4 (listopad 2010): 493–500. http://dx.doi.org/10.1123/jab.26.4.493.
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Manipulating seat configuration (i.e., seat tube angle, seat height and pelvic orientation) alters the bicycle-rider geometry, which influences lower extremity muscle kinematics and ultimately muscle force and power generation during pedaling. Previous studies have sought to identify the optimal configuration, but isolating the effects of specific variables on rider performance from the confounding effect of rider adaptation makes such studies challenging. Of particular interest is the influence of seat tube angle on rider performance, as seat tube angle varies across riding disciplines (e.g., road racers vs. triathletes). The goals of the current study were to use muscle-actuated forward dynamics simulations of pedaling to 1) identify the overall optimal seat configuration that produces maximum crank power and 2) systematically vary seat tube angle to assess how it influences maximum crank power. The simulations showed that a seat height of 0.76 m (or 102% greater than trochanter height), seat tube angle of 85.1 deg, and pelvic orientation of 20.5 deg placed the major power-producing muscles on more favorable regions of the intrinsic force-length-velocity relationships to generate a maximum average crank power of 981 W. However, seat tube angle had little influence on crank power, with maximal values varying at most by 1% across a wide range of seat tube angles (65 to 110 deg). The similar power values across the wide range of seat tube angles were the result of nearly identical joint kinematics, which occurred using a similar optimal seat height and pelvic orientation while systematically shifting the pedal angle with increasing seat tube angles.
3
Wu, Bai Zhong. "The Optimization Design of Cheese Bionic Kneader with Response Surface Method(RSM)". Advanced Materials Research 299-300 (lipiec 2011): 1115–19. http://dx.doi.org/10.4028/www.scientific.net/amr.299-300.1115.
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One kind of cheese kneading experiment test rig was designed, which can imitates artificial kneading movement. Response surface method was used to enhance the performance of the machine. It was investigated that the influence of crank rolling velocity, crank length and crank angle on kneading quality and efficiency. The results show that factors influence the working efficiency list in order as follows: the crank rolling velocity, the angle between a connecting bar and a kneading bar, the crank length. The best combination of optimised parameters are: the crank rolling velocity is 62r/min, the crank length is 28mm, the angle between a connecting bar and a kneading bar is 125°.
4
Łutowicz, Marek, i Dominika Cuper-Przybylska. "Influence of the Instantaneous Angular Speed (IAS) of Marine Diesel Engine on its Indication Results". Solid State Phenomena 236 (lipiec 2015): 204–11. http://dx.doi.org/10.4028/www.scientific.net/ssp.236.204.
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The paper presents a method of transforming the time axis to the axis of the crank angle rotation based on the pressure measured in time domain and simplified model of the engine dynamics. Indicating is to register the pressure in synchronism with the engine crank angle rotation. Usually in the ad hoc measurements the crankshaft rotation angle transducer is avoided, and the measurements are performed in time domain. For further analysis time axis is transformed for crank angle axis on the base of linear transform. Pressure waveforms obtained during the research were subject of the described transform. During the research instantaneous angular speed (IAS) of the engine crankshaft has been changed by reducing fuel dosage to selected cylinders. Mean indicated pressure (MIP) was calculated. Values o pressure on the begging and the end of compression, opening and closing angles of valves were also determined.
5
Worn, Ryan, i Dan B. Dwyer. "A novel method based on first principles to determine the accuracy and reliability of force measurements reported by bicycle power meters." Journal of Science and Cycling 8, nr 1 (9.10.2019): 26–31. http://dx.doi.org/10.28985/jsc.v8i1.396.
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The accuracy and reliability of instrumented bicycle crank systems (i.e. power meters) is an important consideration for sport scientists who evaluate cycling performance and pedalling biomechanics. Many crank systems report power and or force/s on the left and right crank arms separately, or indexes of pedalling effectiveness, although crank systems that have genuinely independent force transducers on the left and right crank arms are rare. There is a need to be able to evaluate the accuracy and reliability of the measurements of power meters without the requirement for expensive and or complex instrumentation. The present study describes a relatively simple and novel method of assessing the accuracy and reliability of measures of crank angle, radial force and tangential force. The method is demonstrated in its application to an instrumented crank system (Axis Cranks ™). Reported crank forces were compared with actual applied forces to determine accuracy and some procedures used to assess the measurement of force were duplicated to determine reliability. The crank system measured crank angle with an average RMS error of 1.84 degrees across pedalling rates of 30-150 r/min. The absolute error of radial and tangential force measurements were 6% and 3.2% respectively (RMSE) and the relative error (accuracy of change in force) of radial and tangential force were 1.48% and 0.25% respectively (RMSE). Repeated measurements of force were found to be highly reliable (intra-class coefficient > 0.998). The method presented in this report could be used to evaluate the accuracy and reliability of other power meters and instrumented crank systems.
6
Chen, B.-C., Y.-Y. Wu i F.-C. Hsieh. "Estimation of engine rotational dynamics using a closed-loop estimator with stroke identification for engine management systems". Proceedings of the Institution of Mechanical Engineers, Part D: Journal of Automobile Engineering 219, nr 12 (1.12.2005): 1391–405. http://dx.doi.org/10.1243/095440705x35062.
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In order to study the effect of the crank sensor noise on the engine management system (EMS), an algorithm using a closed-loop estimator with stroke identification is proposed to estimate the engine rotational dynamics. Estimated crank angle and engine speed are used for fuel injection and ignition control systems. The closed-loop estimator design is based on a linear model by assuming that the engine rotational inertia is constant. Since the effective inertia actually varies with different crank angles, the stability of the proposed algorithm is assessed using the Lyapunov stability theorem. Performances of the proposed and traditional algorithms are evaluated using a non-linear engine model with a four-plus-one-tooth crankshaft wheel in Matlab/Simulink. The estimated crank angle and engine speed of the traditional algorithm can be significantly affected by large sensor noises resulting from the poorly grounded ignition coil. It was found that the proposed algorithm can mitigate the noise impact and thus maintain the desired engine control performance.
7
King, Mark A., i Maurice R. Yeadon. "Determining Subject-Specific Torque Parameters for Use in a Torque-Driven Simulation Model of Dynamic Jumping". Journal of Applied Biomechanics 18, nr 3 (sierpień 2002): 207–17. http://dx.doi.org/10.1123/jab.18.3.207.
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This paper describes a method for defining the maximum torque that can be produced at a joint from isovelocity torque measurements on an individual. The method is applied to an elite male gymnast in order to calculate subject-specific joint torque parameters for the knee joint. Isovelocity knee extension torque data were collected for the gymnast using a two-repetition concentric-eccentric protocol over a 75° range of crank motion at preset crank angular velocities ranging from 20 to 250°s–1. During these isovelocity movements, differences of up to 35° were found between the angle of the dynamometer crank and the knee joint angle of the participant. In addition, faster preset crank angular velocities gave smaller ranges of isovelocity motion for both the crank and joint. The simulation of an isovelocity movement at a joint angular velocity of 150°s–1 showed that, for realistic series elastic component extensions, the angular velocity of the joint can be assumed to be the same as the angular velocity of the contractile component during most of the isovelocity trial. Fitting an 18-parameter exponential function to experimental isovelocity joint torque/ angle/ angular velocity data resulted in a surface that was well behaved over the complete range of angular velocities and within the specified range of joint angles used to calculate the surface.
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Sereda, N. A. "MATHEMATICAL MODEL AND AREA OF EXISTENCE OF THE FAMILY CRANKS AND MOBILE MECHANISMS WITH THE MAXIMUM TRANSMISSION ANGLE". Spravochnik. Inzhenernyi zhurnal, nr 285 (grudzień 2020): 20–26. http://dx.doi.org/10.14489/hb.2020.12.pp.020-026.
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The article examines crank-rocker mechanisms. Such mechanisms are used in transport and technological machines. The article is devoted to the search for a new family of crank-rocker mechanisms. A mathematical model of a new family of crank-rocker mechanisms is obtained. In this family, the maximum transmission angle reaches 90 when the crank angle is 75. Thus, the new family of crank-rocker mechanisms differs from the known families by the position of the mechanism in which the maximum of the transmission angle function takes place. It is shown that, with a certain ratio of link lengths, the new family corresponds to the known families KKM-5 and KKM-7. The area of existence of a new family of crank-rocker mechanisms is established. This area is bounded by the arc of the circle of the unit radius and the curve. The mentioned curve is based on a joint solution of a mathematical model of a new family of mechanisms and the famous Kolchin straight line. The dependence for the minimum transmission angle is obtained. A formula for determining the angle of the rocker arm span is proposed. A graphical interpretation of the mentioned dependencies and formulas is constructed. The scope of existence of a new family of crank-rocker mechanisms and graphical interpretations are used in determining the geometric parameters of mechanisms. These mechanisms are part of a new family of mechanisms.
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Loveikin, Viacheslav, Kostiantyn Pochka, Mykola Prystailo, Maksym Balaka i Olha Pochka. "Impact of cranks displacement angle on the motion non-uniformity of roller forming unit with energy-balanced drive". Strength of Materials and Theory of Structures, nr 106 (24.05.2021): 141–55. http://dx.doi.org/10.32347/2410-2547.2021.106.141-155.
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The impact of the cranks displacement angle on the motion non-uniformity is determined for three forming trolleys of a roller forming unit with an energy-balanced drive mechanism. At the same time, the specified unit is presented by a dynamic model with one freedom degree, where the extended coordinate is taken as the angular coordinate of the crank rotation. For such a model, a differential equation of motion is written, for solved which a numerical method was used. The inertia reduced moment of the whole unit, and the resistance forces moment, reduced to the crank rotation axis, to move of forming trolleys during the formation of products from building mixtures are determined, and also the nominal rated power of the electric motor was calculated, when solved a differential equation of motion. According to these data, asynchronous electric motor with a short-circuited rotor was chosen, for which a mechanical characteristic is constructed by the Kloss formula. Having solved the differential equation of motion with all defined characteristics, we obtain the change function of the crank angular velocity from start-up moment and during steady motion mode. After that, we calculated the time corresponding to the angular velocity value, and obtained the change function of the crank angular acceleration from start-up moment and during steady motion mode. The motion non-uniformity of the roller forming unit has been determined by the motion non-uniformity factor, the motion dynamism factor and the extended factor of motion assessment during steady motion mode. The impact of drive cranks displacement angle on the motion non-uniformity has been traced, as a result, the specified factors have the minimum values at cranks displacement on the angle Δφ=60°. The results may in the future are used to refine and improve the existing engineering methods for estimating the drive mechanisms of roller forming machines, both at design stages and in practical use.
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Midha, A., R. J. Cipra i K. Farhang. "Analysis and Design of Basic Linkages for Harmonic Motion Generation". Journal of Mechanisms, Transmissions, and Automation in Design 107, nr 4 (1.12.1985): 499–506. http://dx.doi.org/10.1115/1.3260752.
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This paper deals with basic planar linkages driven by relatively small cranks, and as a consequence generating approximate simple harmonic motion at the output members. A unique approach is presented to yield the kinematic equations, as exemplified by planar crank-rocker and offset slider-crank linkages. The method involves the presumption of a mean linkage configuration and a small motion excursion therefrom. Its validity is demonstrated by means of several error plots, generated for varying, nondimensional linkage parameters and a constant mean transmission angle. These plots also serve to illustrate the order of approximation involved for a particular combination of parameters. Finally, the synthesis of a crank-rocker linkage for a representative set of requirements is exemplified using the equations developed herein.
11
Farhang, K., A. Midha i A. Bajaj. "A Higher-Order Analysis of Basic Linkages for Harmonic Motion Generation". Journal of Mechanisms, Transmissions, and Automation in Design 109, nr 3 (1.09.1987): 301–7. http://dx.doi.org/10.1115/1.3258794.
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In an earlier work, a perturbation technique was first presented to obtain approximate simple harmonic equations for describing the output motions of rudimentary linkages, i.e., a crank-rocker and a slider-crank, with relativley small input cranks. The technique involved consideration of a small motion excursion about a so-called “mean linkage configuration.” These equations were facilitated through truncation of the binomial series expansion of the output motions, expressed in terms of the input crank angle. Assuming a small crank to ground link length ratio, terms containing second or higher powers of this ratio were neglected. This paper retains terms containing higher powers in an effort to improve upon (i) the definition of the mean linkage configuration, and (ii) the harmonic motion content representation of the output motions. The improvements made due to the “modified” equations, relative to the “original” ones, are pictorially presented as being significant.
12
Tanık, Engin. "Transmission angle in compliant slider-crank mechanism". Mechanism and Machine Theory 46, nr 11 (listopad 2011): 1623–32. http://dx.doi.org/10.1016/j.mechmachtheory.2011.07.001.
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MOSNEGUTU, EMILIAN, NARCIS BARSAN, MIRELA PANAINTE-LEHADUS, DANA CHITIMUS i CLAUDIA TOMOZEI. "INFLUENCE OF THE CRANK MECHANISM POSITION IN THE MOTION OF AN OSCILLATING SIEVE". Journal of Engineering Studies and Research 27, nr 4 (15.12.2021): 36–43. http://dx.doi.org/10.29081/jesr.v27i4.297.
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This article presents a study that aims to visualize the influence exerted by the position of the crank mechanism on the motion performed by the sieve supports respectively, on the displacement of an oscillating sieve. The study was oriented for a specific constructive case and involves the connecting rod position changing, the drive mechanism in relation to the horizontal, respectively at the angles 0 - 75° and -45 - 0°. Also, were identifying the variation of the angle described by the motion of the sieve support. From the obtained results analysis, it was found that in the case of 12.71° of the connecting rod angle, in relation to the horizontal, the lowest value of the angle described by the motion of the tie rod between the extreme points was obtained. Also, for the value of the connecting rod angle of approximately 6.5° equal angles described by the extreme positions of the sieve support in relation to the vertical were obtained. It is found that the variation of the connecting rod angle directly influences the variation of the angles described by the connecting rod in relation to the horizontal, the measured value being corresponding to the extreme points P1 and P2.
14
Han, Haotong. "Synthesis on cardioid crank rocker mechanism with approximate uniform motion". Journal of Physics: Conference Series 2557, nr 1 (1.07.2023): 012008. http://dx.doi.org/10.1088/1742-6596/2557/1/012008.
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Abstract The cardioid crank is a planetary mechanism that generates a cardioid line. It is a crank with varying length and speed that moves along the cardioid line. The cardioid crank is used to replace the crank of the crank rocker mechanism, and its rocker mechanism with approximate uniform motion is obtained. The kinematic analysis method of the cardioid crank rocker mechanism is studied in this paper. The calculating method for the limit position and oscillating angle and the time ratio of the guide bar are given. Finally, the approximate uniform motion conditions of the rocker are obtained. The synthesis method of the approximate uniform motion mechanism is put forward in accordance with the time ratio or rocker oscillate angle, the minimum length of the guide bar is calculated, and the influence of center distance on the kinematic performance of the mechanism is discussed.
15
Suareo, F. O., i K. C. Gupta. "Design of Quick-Returning R-S-S-R Mechanisms". Journal of Mechanisms, Transmissions, and Automation in Design 110, nr 4 (1.12.1988): 423–28. http://dx.doi.org/10.1115/1.3258939.
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An algebraic method is presented to synthesize quick-returning R-S-S-R mechanisms which satisfy the given time-ratio and follower oscillation angle requirements. In these designs, the three parameters, which define the follower spheric joint, satisfy a quadratic condition. When the shaft angle between the input and output shafts is zero, this quadratic condition reduces to the equation of a circle which is a familiar classical result for the planar case. The solution space for the quick-returning R-S-S-R linkage is such that, for each set of choices for crank length a2, follower axial distance S4, and initial follower angle φ0, there are four sets of follower length a4, initial crank angle θ0, crank axial distance S2, and coupler length a3. These designs are screened so that they do not have branch defect, have transmission angle values in a given range, and have reasonable link length proportions.
16
Farhang, K., i Y. S. Zargar. "Design of Spherical 4R Mechanisms: Function Generation for the Entire Motion Cycle". Journal of Mechanical Design 121, nr 4 (1.12.1999): 521–28. http://dx.doi.org/10.1115/1.2829492.
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Spherical 4R mechanisms are studied for which the crank is relatively smaller than the remaining links. The theory of small-crank mechanisms is applied to obtain approximate descriptions for the follower angular displacement in terms of the input crank angle. The follower angle is presumed to comprise a mean and a perturbational motion. This results in an approximate expression in which the follower displacement is given as a linear combination of simple harmonic functions of the first and second harmonics of the crank angle. The approximate equations are utilized for synthesis of spherical 4R mechanisms for function generation. In contrast to the conventional design procedures, the use of the approximate equations allows the synthesis of spherical mechanisms in which a prescribed function is satisfied for the entire motion of the mechanism. In addition to design examples, sample error charts are provided to assist the designer in ascertaining feasible ranges for design and corresponding orders of error.
17
Zweiri, Y. H., J. F. Whidborne i L. D. Seneviratne. "Detailed analytical model of a single-cylinder diesel engine in the crank angle domain". Proceedings of the Institution of Mechanical Engineers, Part D: Journal of Automobile Engineering 215, nr 11 (1.11.2001): 1197–216. http://dx.doi.org/10.1243/0954407011528734.
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A detailed analytical non-linear dynamic model for single-cylinder diesel engines is developed. The model describes the dynamic behaviour between fuelling and engine speed and includes models of the non-linear engine and dynamometer dynamics, the instantaneous friction terms and the engine thermodynamics. The model operates in the crank angle domain. The dynamometer model enables the study of the engine behaviour under loading. The instantaneous friction model takes into consideration the viscosity variations with temperature. Inertia variations with piston pin offset are presented. In-cycle calculations are performed at each crank angle, and the correct crank angles of ignition, speed variations, fuel supply and air as well as fuel burning rate are predicted. The model treats the cylinder strokes and the manifolds as thermodynamic control volumes by using the filling and emptying method. The model is validated using experimentally measured cylinder pressure and engine instantaneous speeds, under transient operating conditions, and gives good agreement. The model can be used as an engine simulator to aid diesel engines control system design and fault diagnostics.
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Su, Hui. "Rocker Mechanism Study of Crank Angle between Extreme Positions". Applied Mechanics and Materials 268-270 (grudzień 2012): 1270–73. http://dx.doi.org/10.4028/www.scientific.net/amm.268-270.1270.
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Harman, E., H. G. Knuttgen i P. Frykman. "Automated data collection and processing for a cycle ergometer". Journal of Applied Physiology 62, nr 2 (1.02.1987): 831–36. http://dx.doi.org/10.1152/jappl.1987.62.2.831.
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A system is described for collection and processing of data from a cycle ergometer. Cycle pedals, specially made to withstand the extremely high forces exerted during maximal power cycling, contain transducers to measure pedal angle relative to the crank and foot forces both perpendicular and parallel to the pedal surface. An additional transducer monitors crank position. Output signals are conditioned, amplified, digitized by a 12-bit analog-to-digital converter, fed into a computer at 100 Hz/channel, and mathematically smoothed to attenuate noise. For each sample interval, foot force components perpendicular and parallel to the crank arm are calculated. Power generated on each crank revolution is determined from transducer information. Computer graphics display pedaling parameters vs. crank angle in both rectangular and circular format. Data files containing variables descriptive of pedaling force curves are produced to enable computerized statistical analysis of cycling performance.
20
Ahmadi, Bahman, i Behnam Ahmadi. "Optimal synthesis of crank-rocker mechanisms with optimum transmission angle for desired stroke and time-ratio using genetic programming". Advances in Mechanical Engineering 14, nr 10 (październik 2022): 168781322211312. http://dx.doi.org/10.1177/16878132221131291.
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Dimensional synthesis of crank-rocker mechanisms applied to provide some desired values of stroke and time ratio, is of utmost importance for designing an efficient mechanism. In the synthesis and manufacturing of crank-rocker mechanisms, the designers are further challenged by other design criteria, such as quality of motion. In this study, a novel approach based on genetic programming (GP) is proposed for dimensional synthesis of planar crank-rocker mechanisms with optimum transmission angle over the desired stroke and time-ratio. An analytical approach is elaborated which leads to an interesting relationship of length of the coupler and rocker links. It is, therefore, advised that by adopting equal lengths for coupler link and rocker link, one can guarantee the optimality of the transmission angle’s deviation ([Formula: see text]), ensuring the Grashof condition. Consequently, through an inverse modeling approach, GP method is utilized to construct some explicitly mathematical formulas to represent all the sizes and dimensions of the crank-rocker mechanism based on the any desired values of both stroke and time-ratio. In this way, an input-output data set consisting of all the dimensions and the sizes of the links as the input variables and both the stroke and time-ratio as output variables is first constructed using the pertinent mathematical equations. Indeed, such approach of inverse modeling using GP simplifies greatly the synthesis of the crack-rocker mechanisms for any desired values of both stroke and time-ratio. The proposed approach has been applied for kinematic synthesis of a crank-rocker mechanism. A comparison between the obtained results of this work and the analytic method, clearly illustrates the efficiency of the proposed approach.
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Kirby, James T. "LARGE-ANGLE PARABOLIC EQUATION METHODS". Coastal Engineering Proceedings 1, nr 20 (29.01.1986): 32. http://dx.doi.org/10.9753/icce.v20.32.
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Large-angle parabolic equation methods for the propagation of surface water waves are discussed. The methods described here are limited to forms which are solvable by the Crank-Nicolson method, but are successful in opening the allowed range of propagation directions to ~ 50° with respect to normal incidence.
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Li, Chao, Yang Yu i Man Zhao. "Analysis of Loads at Crankshaft Bearing for Scroll Compressor". Applied Mechanics and Materials 160 (marzec 2012): 42–46. http://dx.doi.org/10.4028/www.scientific.net/amm.160.42.
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According to the tangential force of crank pin approximately for radial force four times, between the radial gas force Fr and tangential gas force Ft acting on the orbiting scroll, the radial force is invariableness with the spindle rotation angle, but tangential force Ft with the spindle rotation angle changes, and in the discharge angle θ* at maximum. As a result of our comprehensive analyses to loads at crankshaft bearing of the scroll compressor as well as installation angle of the counter weight and mass of the counterweight, it is concluded that the imbalance residual quantity of the crank pin tangential force effects on crankshaft bearing and radial force acting on the crank pin, which results from gas force of orbiting scroll, is balanced, and the vibration of the scroll compressor is decreased. This paper puts forward a set of formulas, which are derived based on analysis of the loads at crankshaft of scroll compressor. The formulas can be used to determine the parameters of installation angle of the counterweight and the force of loads at crankshaft for scroll compressor.
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Du, Zheng, Bowen Zhang i Jiguang Han. "Synthesis of cardioid crank rocker dwell mechanism". Journal of Physics: Conference Series 2557, nr 1 (1.07.2023): 012010. http://dx.doi.org/10.1088/1742-6596/2557/1/012010.
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Abstract The cardioid crank rocker mechanism is a mechanism obtained by replacing the crank of a crank rocker mechanism with a cardioid crank. The cardioid crank is a planetary mechanism capable of generating cardioid curves. Using the cardioid crank as the driving crank of the crank rocker mechanism is equivalent to a crank with variable speed and length moving along the cardioid line, changing the motion characteristics of the rocker. The motion characteristics of the cardioid crank rocker mechanism are studied, and the limit position of the rocker and the calculation method of the intermittent interval is given. The influence of the planetary linkage length and center distance on the intermittent interval, and how to complete the mechanical design with known intermittent angle are discussed respectively, and a comprehensive analysis is made.
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Zhang, Meng, Jinhua Wang, Zuohua Huang i Norimasa Iida. "Numerical study of effects of the intermediates and initial conditions on flame propagation in a real homogeneous charge compression ignition engine". Thermal Science 18, nr 1 (2014): 79–87. http://dx.doi.org/10.2298/tsci121225062z.
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The premixed flame speed under a small four stock homogeneous charge compression ignition engine, fueled with dimethyl ether, was investigated. The effects of intermediate species, initial temperature, initial pressure, exhaust gas recirculation, and equivalence ratio were studied and compared to the baseline condition. Results show that, under all conditions, the flame speeds calculated without intermediates are higher than those which took the intermediates in consideration. Flame speeds increase with the increase of crank angle. The increase rate is divided into three regions and the increase rate is obviously high in the event of low temperature heat release. Initial temperature and pressure only affect the crank angle of flame speed, but have little influence on its value. Equivalence ratio and exhaust gas recirculation ratio do not only distinctly decrease the flame speed, but also advance the crank angle of flame speed.
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Ismail, Ahmad Yusuf, Gangta Na i Bonyong Koo. "Topology and Response Surface Optimization of a Bicycle Crank Arm with Multiple Load Cases". Applied Sciences 10, nr 6 (24.03.2020): 2201. http://dx.doi.org/10.3390/app10062201.
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This paper presents an application of topology optimization and response surface method to optimize the geometry of a bicycle crank arm and the experimental validation of it. This is purposely to reduce the crank arm mass and create a preliminary design of a lightweight structure necessary for the high-performance bicycle development. A three-dimensional bike crank arm model was made in the SpaceClaim software followed by a static finite element analysis using ANSYS Workbench 2019 R1. A multiple cycling load was applied simultaneously in seven crank angles of 30, 45, 60, 90, 120, 135, and 150° relative to the horizontal position to create the multiple loads to the crank. From there, topology optimization was then conducted to investigate the effect of mass constraint, stress constraint, angle of cycling, and crank materials on the topological pattern result. To minimize stress concentration at corners, a shape optimization using the response surface method was conducted and obtained the final geometry. From the result, it is shown that both optimization methods not only successfully reduce the crank arm mass and provide several optimum design options but also are able to reduce the maximum stress in the crank arm up to 20% after the optimization process. The experimental validation using a newly developed wireless measurement system shows a considerable agreement to the numerical results.
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Caldwell, Graham E., Li Li, Steve D. McCole i James M. Hagberg. "Pedal and Crank Kinetics in Uphill Cycling". Journal of Applied Biomechanics 14, nr 3 (sierpień 1998): 245–59. http://dx.doi.org/10.1123/jab.14.3.245.
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Alterations in kinetic patterns of pedal force and crank torque due to changes in surface grade (level vs. 8% uphill) and posture (seated vs. standing) were investigated during cycling on a computerized ergometer. Kinematic data from a planar cine analysis and force data from a pedal instrumented with piezoelectric crystals were recorded from multiple trials of 8 elite cyclists. These measures were used to calculate pedal force, pedal orientation, and crank torque profiles as a function of crank angle in three conditions: seated level, seated uphill, and standing uphill. The change in surface grade from level to 8% uphill resulted in a shift in pedal angle (toe up) and a moderately higher peak crank torque, due at least in part to a reduction in the cycling cadence. However, the overall patterns of pedal and crank kinetics were similar in the two seated conditions. In contrast, the alteration in posture from sitting to standing on the hill permitted the subjects to produce different patterns of pedal and crank kinetics, characterized by significantly higher peak pedal force and crank torque that occurred much later in the downstroke. These kinetic changes were associated with modified pedal orientation (toe down) throughout the crank cycle. Further, the kinetic changes were linked to altered nonmuscular (gravitational and inertial) contributions to the applied pedal force, caused by the removal of the saddle as a base of support.
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Lu, Yingying, i Wanhua Su. "Effects of the injection parameters on the premixed charge compression ignition combustion and the emissions in a heavy-duty diesel engine". Proceedings of the Institution of Mechanical Engineers, Part D: Journal of Automobile Engineering 231, nr 7 (23.04.2017): 915–26. http://dx.doi.org/10.1177/0954407017701023.
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Numerous combustion strategies have been suggested for compression ignition engines in order to meet the stringent emission regulations with minimal sacrifice in the fuel economy. Premixed charge compression ignition combustion has the potential to reduce the nitrogen oxide emissions and the soot emissions while maintaining a high thermal efficiency and has become the research focus recently. Experiments and simulations were used to study the effects of the injection mode and the injection timing on the premixed charge compression ignition combustion and the emissions in a heavy-duty diesel engine at low and medium loads. The results reveal the following. At low loads, when the injection timing of a single injection is 35° crank angle before top dead centre because of the impinging position of the spray, the mixture is divided into two parts: the fuel above the chamber and the fuel in the piston bowl. This helps to utilize fully the in-cylinder air to form a homogeneous mixture. Also the nitrogen oxide emissions are the lowest. At medium loads, with a single injection, the injection mass is increased, the injection duration is prolonged and the mixing timing is reduced. As a result, the soot emissions, the carbon monoxide emissions and the unburned hydrocarbon emissions are increased dramatically; the best emissions are gained at an injection timing of 35° crank angle before top dead centre owing to the combined effect of the optimized mixing time and the optimized mixing space. At medium loads, with multiple injections, the injection mass is divided into four pulses, the mixing timings of which are all increased. The mixing space of the fuel–air mixture is also improved, and a more homogeneous mixture is obtained, which is beneficial to decreasing the soot emissions, the carbon monoxide emissions and the unburned hydrocarbon emissions in comparison with those for the single-injection case. When the injection timings of multiple injections are 80° crank angle before top dead centre, 65° crank angle before top dead centre, 50° crank angle before top dead centre and 35° crank angle before top dead centre, the best trade-off between the performance and the emissions can be achieved at medium loads.
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Söylemez, Eres. "Classical transmission-angle problem for slider–crank mechanisms". Mechanism and Machine Theory 37, nr 4 (kwiecień 2002): 419–25. http://dx.doi.org/10.1016/s0094-114x(01)00083-0.
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Ma, Zhi Yi, Fu Lei Zhao, Ya Peng Li, Meng Lv, Le Xue i Teng Zhang. "Analysis and Calculation of Complete Combustion Level of Biodiesel Compared with Diesel". Advanced Materials Research 512-515 (maj 2012): 496–99. http://dx.doi.org/10.4028/www.scientific.net/amr.512-515.496.
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Many studies and experiments prove that biodiesel produces less CO, HC and smoke emissions, produces more NOX emission and burns more completely than diesel. Firstly, for evaluating complete combustion level for biodiesel compared with diesel, the paper indicates that heat release ratio can not act independently as the standard; secondly the second maximal heat release ratio and combustion beginning crank angles are combined with Peak heat release ratio; lastly, CAcenter(the corresponding crank angle of centric of instantaneous heat release ratio curve) is introduced and it is the best factor which can accurately reflect the complete combustion level of biodiesel.
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Kang, Yi Hua, Jun Tu, Jian Bo Wu i Yan Hua Sun. "The High-Speed Ultrasonic Testing Method for Steel Pipes Based on Linear Reciprocating Probes". Advanced Materials Research 301-303 (lipiec 2011): 919–23. http://dx.doi.org/10.4028/www.scientific.net/amr.301-303.919.
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This paper presents the high-speed ultrasonic testing methods for steel pipes currently, and points the existing difficulties, such as the instability in signal transmission, the problem of water coupling, and so on. Then the inspection method based on linear reciprocating probes is proposed to achieve the purpose of fewer probes and higher detecting speed. The mathematics model which adopts the slider-crank mechanism to realize the probes swinging fast in line is established as there is blind spot between the adjacent probes in high-speed inspection. With the help of simulation of Matlab, the relation curve between the rotation speed of crank and the rotation angle of crank is acquired, as well as the line speed of the steel pipe and the rotation angle of crank. The experiment platform is set up according to the simulation data, and the results verify the feasibility of the method.
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Harada, Takashi, Naomichi Tanaka i Takayuki Fujitsuka. "Design of an Arc-Core Moving Mechanism for Injection Molding Using a Link and Cam Mechanism". International Journal of Automation Technology 15, nr 3 (5.05.2021): 366–74. http://dx.doi.org/10.20965/ijat.2021.p0366.
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A novel plastic injection mold design for a product with a deep arc-hole based on the kinematic analysis is proposed. To move the wide angle arc-core, a hybrid mechanism combining a slider-crank and a swing cam is designed. The force transmission coefficient of the slider-crank and the pressure angle of the swing cam are used to evaluate the dimensions of the mechanism. The motion of the designed mechanism was confirmed by using a prototype made with a 3D printer.
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Al-Smadi, Y. M., K. Russell i R. S. Sodhi. "Four-bar motion generation with elasticity constraints and optimization". Proceedings of the Institution of Mechanical Engineers, Part K: Journal of Multi-body Dynamics 223, nr 3 (2.06.2009): 245–53. http://dx.doi.org/10.1243/14644193jmbd173.
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In conventional planar four-bar motion generation, all mechanism links are assumed rigid or non-deforming. Although the assumption of link rigidity in kinematic synthesis may be generally appropriate and often practiced, a statically loaded planar four-bar mechanism will undergo a degree of elastic deflection, particularly the crank and follower links. In this work, a non-linear optimization problem is formulated for planar four-bar motion generation that considers an applied coupler force and corresponding crank static torque, crank transverse deflection, and follower buckling. The output from the non-linear optimization problem – mechanism fixed and moving pivot loci – are input for a search algorithm that down selects a mechanism solution that satisfies transmission angle conditions, Grashof conditions, and a mechanism compactness condition. The final output of the presented method is planar four-bar motion generator that approximates prescribed coupler poses with satisfactory crank deflection and without follower buckling and also satisfies conditions for link rotatability, transmission angle and compactness.
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Raghunathan, C., i C. Manoharan. "Investigations of mechanical behavior in gear pump using design of software". International Journal of Engineering & Technology 3, nr 4 (15.09.2014): 435. http://dx.doi.org/10.14419/ijet.v3i4.1917.
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This research study focused on the various aspects of tribological phenomenon using design of experiments approach, results are analyzed and compared to evaluate the gear performance. Though lot of research work had been carried out on the hydrodynamic gear under static loads, till date no one consider the parameter say stiffness, damping co-efficient, squeeze film effects and the pressure distribution at various crank angle under dynamic load conditions and its effects on inertia forces of gear pump. It covers sinusoidal load, journal speed, face width and mass flow rate with respect to variations in oil film thickness. Frictional test rig was used to measure the frictional force and oil film thickness at various crank angles for every three minutes at an interval of every 15 degree crank angle. The response surface methodology (RSM) analysis shows appreciable increases in respect of performances in mass flow rate, face width, speed and loading against the Taguchi design of experiment results whereas the film thickness is almost same in both RSM and Taguchi design of experiment results. Particular attention is given in this research exertion to learn how the variation in gear dimensions influences the characteristics of the hydrodynamic gear pump. Keywords: Hydrodynamic Gear Pump, Oil Film Thickness, Mathematical Modeling, Taghuchi and RSM, Eddycurrent Cap Sensor.
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Varshney, Ayush, Arshad H. Khan, M. Yaqoob Yasin, Zahid A. Khan i Mohammad Asjad. "On the optimal dynamic design of laminated composite folded plates: a multi-criteria decision analysis". Multidiscipline Modeling in Materials and Structures 16, nr 2 (4.10.2019): 322–39. http://dx.doi.org/10.1108/mmms-06-2019-0116.
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Purpose The purpose of this paper is to present the multi-objective optimization of the dynamic response of isotropic and laminated composite folded plates. The dynamic analysis has been carried out using the finite element method based on the first-order shear deformation theory. Design/methodology/approach Hamilton’s principle has been employed for the derivation of the governing equations. Natural frequencies are obtained using the eigenvalue extraction method. The optimal combination of the crank angle, lamination scheme and boundary conditions on the natural frequencies of folded plates for their safe and optimal dynamic design has been obtained. The analysis has been carried out using finite element approach based on FSDT to obtain the dynamic equation of single- and double-fold laminated plates. In total, 15 experiments as per Taguchi’s standard L15 orthogonal array have been performed. Further, standard deviation (SD) based TOPSIS method is used to perform multi-response optimization of folded plates in order to rank the combination of the input parameters. Findings SD integrated with TOPSIS reveals that Experiment No. 8 (crank angle=90° and anti-symmetric lamination scheme=0°/90°/0°/90°), Experiment No. 14 (crank angle=150° and anti-symmetric lamination scheme=0o/90o/0o/90o), Experiment No. 2 (crank angle=30° and anti-symmetric lamination scheme=0°/90°/0°/90°) and Experiment No. 3 (crank angle=30° and symmetric lamination scheme=0°/90°/0°/90°) occupy rank 1 for one fold, one end clamped, one fold, two ends clamped, two folds, one end clamped and two folds, two ends clamped conditions, respectively, in order to maximize the modal response corresponding to the fundamental mode. Originality/value SD-based technique for order of preference by similarity to ideal solution (TOPSIS) method is used to rank the process parameters. The optimum combination of the input parameters on the multi-response optimization of dynamics of the folded plates has also been evaluated using the analysis of mean (ANOM).
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Wang, Yu. "Kinematic Analysis and Optimization Design of an Eccentric Crank Slide-Block Mechanism Based on ADAMS". Advanced Materials Research 189-193 (luty 2011): 997–1000. http://dx.doi.org/10.4028/www.scientific.net/amr.189-193.997.
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Operating principle and motion characteristics of an eccentric crank slide-block mechanism are analyzed. A virtual prototype model of the eccentric crank slide-block mechanism is set up based on ADAMS,a simulation software. The kinematics analysis of the eccentric crank slide-block mechanism,it is given.Under the premise of meeting the requirements of slide stroke and travel velocity-ratio coefficient, based on ADAMS, each component size of the eccentric crank slide-block mechanism with best pressure angle (α max ) min can be easily obtained. The equations and the calculations can be used in engineering practice.
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Fernandez, Victor. "Characteristics of Slider Crank Mechanism Using Modeling Simulations". ACMIT Proceedings 4, nr 1 (19.03.2017): 127–35. http://dx.doi.org/10.33555/acmit.v4i1.67.
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This document will analyze the different effects of the length and the angular velocity affecting theperformance of the slider crank system. The performance of the slider crank system is simulated and shownusing MATLAB with reference of the model represented by a mathematical formula. The result of thesimulation is represented by several graphs, showing the relation of the length and angular velocity of therotary motion of the slider crank mechanism and the angle generated by the translational motion of theslider.
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Chainov, N. D., i P. R. Vallejo Maldonado. "Balancing the Moments of a VR5 Engine Taking into Account a Desaxial Crank Mechanism and Cylinder Camber Angle". Proceedings of Higher Educational Institutions. Маchine Building, nr 05 (722) (maj 2020): 41–49. http://dx.doi.org/10.18698/0536-1044-2020-5-41-49.
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Automobile piston engines with a desaxial crank mechanism are characterized by increased vibration activity associated with a cyclic change in the pressure of the working fluid in the cylinders and inertial forces associated with the reciprocating and rotational movement of the crank mechanism moving masses. Properties reflecting the consumer properties of the engine, including acoustic characteristics, are largely determined by the level of vibration of the structural elements of the desaxial crank mechanism and, first of all, by the balance of inertial forces during operation. The article discusses balancing of five-cylinder four-stroke VR type engines with a desaxial crank mechanism and uniform flash alternation. The authors introduce formulas that can be used to determine and analyze moments of the inertia forces of the reciprocating and rotating masses arising in VR5 engines at the set values of the cylinder camber angle, the ratio of the crank radius to the connecting rod length and the relative displacement of the cylinder axis. A method of balancing the moments of inertia forces of the reciprocating and rotating masses is proposed.
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Swamy, Baragati Raghavendra. "Design and Optimization of Crankshaft for 4-Stroke Single Cylinder Engine using Pro-E". International Journal for Research in Applied Science and Engineering Technology 10, nr 6 (30.06.2022): 3816–28. http://dx.doi.org/10.22214/ijraset.2022.44182.
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Abstract: The design of a crankshaft is of 4 stroke single cylinder engine. so that two revolution of crankshaft for each stroke. The peak pressure acting on the engine crankshaft is 63 bar. The crankshaft of the located model is designed using pro engineering with the accurate dimensions and material standards of located Honda crankshaft. Pro engineer is one of the best design software in design tools were we can easily design components based on it dimensions and analyzing it with accurate results. Crankshaft dynamic analysis is done by using mechanism. Dynamic analysis is used to find out the motion of the bodies with represents to applied loads with the time frame of crank angle. The crank angle is calculated with respect to seconds as it takes 0.008 sec for each stroke with to revolution. This value re calculated by using spread sheet. The results of the analysis indicate the forces diagram of given connections at different crank angle. The piston acceleration is calculated to find out the theoretical and experimental results values of graph shown in results.
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TUTAK, Wojciech, i Arkadiusz JAMROZIK. "Modelling of the thermal cycle of a gas engine using AVL FIRE Software". Combustion Engines 141, nr 2 (1.05.2010): 105–13. http://dx.doi.org/10.19206/ce-117152.
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Paper presents results of modelling gas engine thermal cycle using AVL FIRE and KIVA 3V software. There are described three combustion models used in software. KIVA and FIRE software are used in Institute of Internal Combustion Engines and Control Engineering for analysis of thermal cycle of IC engines. FIRE software gives many possibilities with many combustion models. All used combustion models are dependent on turbulence of flow field before ignition. Comparison of modelling results of thermal cycle of IC engine is presented in paper. Pressure, temperature, heat release and turbulence parameters variations in function of crank angle as well as spatial distribution of above mentioned quantities at selected crank angles were determined.
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Hanafi, M. H. M., W. M. F. Wan Mahmood, Mohd Fadzli Bin Abdollah, S. A. Rafeq, N. F. M. Nor, Z. M. Zulfattah, S. A. Shamsudin i A. Ibrahim. "Comparison of Soot Particle Movement based on Crank Angle". Procedia Engineering 68 (2013): 245–50. http://dx.doi.org/10.1016/j.proeng.2013.12.175.
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Şaka, Ziya. "The double crank RSSR mechanism with constant transmission angle". Forschung im Ingenieurwesen 62, nr 5 (maj 1996): 146–48. http://dx.doi.org/10.1007/bf02607969.
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Zhang, Li Hua, Tao Tao Liu i Guang Hui Li. "A Design of Ginkgo Cleaner". Applied Mechanics and Materials 397-400 (wrzesień 2013): 919–23. http://dx.doi.org/10.4028/www.scientific.net/amm.397-400.919.
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In order to solve the cleaning problem of ginkgo after husking, the author puts forward a design scheme of air-shaker cleaning device for ginkgo kernel and husk. The device consists of feed, fan, shaker and outlet. The parameters of shaker are determined: sieve motion direction angle is 8o, sieve angle of inclination is 20o, crank radius is 0.020m, crank rotational speed n is 320rmp. Test results show that the cleaner has steady transmission, low noise, stable performance and its productivity is 2.2t/h, loss ratio is 1.20%, cleaning ratio is 95.21%. It can meet the production requirements.
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Sun, Ying Jie, Yang Li, Chun Yu Wang, Yao Chun Li i Yun Feng Liang. "Research of Working Mode Conversion Based on GDI Engine". Applied Mechanics and Materials 741 (marzec 2015): 546–49. http://dx.doi.org/10.4028/www.scientific.net/amm.741.546.
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This paper designs the control strategy of working mode conversion from stoichiometric homogeneous mixture to lean homogeneous mixture. First of all, after the types and parameters of electric hardware were selected in this system, a complete circuit layout of engine control system was designed, which used microcontroller named MC9S12XDP512 as control chip and the test bench was built. Then, we adjust the fuel injection pulse width and throttle opening to realize lean burn (lambda = 1.4) of torque being 40N.m at speed of 2500 r / min, and adjust injection timing to find the best injection timing which is 350 crank angle degree, and adjust the ignition advance angle to find the best ignition advance angle which is 13 crank angle degree. Finally, the work mode conversion was completed by the optimal parameters linear interpolation, reducing the fuel injection pulse width and increasing the throttle opening at the same time.
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R.Girimurugan i A. S. Nithiya guru. "EFFECT OF CUMULATIVE HEAT RELEASE OF A VARIABLE COMPRESSION RATIO DIESEL ENGINE OPERATING WITH PONGAMMIA PINNATA OIL BLENDS FOR DIFFERENT CRANK ANGLES". EPH - International Journal of Science And Engineering 2, nr 3 (27.09.2016): 22–30. http://dx.doi.org/10.53555/eijse.v2i3.162.
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In this experimental study cumulative heat release of a variable compression ratio (VCR) Diesel engine operating with diesel and Pongamia pinnata oil blends were studied under different crank angle (-360˚ to +359˚), five different percentage loading conditions (0%, 25%, 50%, 75% & 100%), two compression ratio (17:01 & 18:01) and three different Pongamia pinnata oil blends (B10, B15 & B20) which are blended with diesel by volumetric basis (100 ml Pongamia pinnata oil: 900 ml pure Diesel, 150 ml Pongamia pinnata oil: 850 ml pure Diesel, 200 ml Pongamia pinnata oil: 800 ml pure Diesel) respectively. For comparative purpose initially the engine was run by pure Diesel. This study shows that the cumulative heat release is maximum (1.01 kJ//s) when the engine operates with Pongamia pinnata oil (B10 blend) which was blended with pure Diesel on full load conditions (100% load) at a crank angle of 42˚ and compression ratio 17:01. This study shows that the cumulative heat release is minimum (0.58 kJ/s) when the engine operates with pure Diesel on no load conditions (0% load) at a crank angle of 48˚ and compression ratio 17:01.
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Mohammed, S. E., M. B. Baharom i A. Rashid A. Aziz. "Estimation of Counterweight for Shaking Force Balancing of a Crank-Rocker Mechanism". Applied Mechanics and Materials 663 (październik 2014): 135–40. http://dx.doi.org/10.4028/www.scientific.net/amm.663.135.
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This paper proposes a method of balancing the shaking force of a crank-rocker mechanism which rotates at a constant angular speed with zero-unbalanced angle. In this approach, the kinematic synthesis and dynamic behavior of the mechanism are combined. The method is realized by modeling the mass of the connecting rod to represent two concentrated masses placed at the crank and rocker pins. The shaking forces balancing are done by adding counterweight masses to the crank and the rocker. The verification and numerical computation of the proposed balancing technique were carried out using ADAMS Software. The results showed that the sum of all the resultant forces was completely eliminated for the newly-balanced crank rocker mechanism.
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Akalin, Ozgen, i Golam M. Newaz. "Piston Ring-Cylinder Bore Friction Modeling in Mixed Lubrication Regime: Part II—Correlation With Bench Test Data". Journal of Tribology 123, nr 1 (29.12.1999): 219–23. http://dx.doi.org/10.1115/1.1286338.
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A bench friction test system for piston ring and liner contact, which has high stroke length and large contact width has been used to verify the analytical mixed lubrication model presented in a companion paper (Part 1). This test system controls the speed, temperature and lubricant amount and records the friction force, loading force, crank angle signal and contact temperature data simultaneously. The effects of running speed, applied normal load, contact temperature and surface roughness on friction coefficient have been investigated for conventional cast-iron cylinder bores. Friction coefficient predictions are presented as a function of crank angle position and results are compared with bench test data. Analytical results correlated well with bench test results.
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Sui, Wenbo, i Carrie M. Hall. "Combustion phasing modeling and control for compression ignition engines with high dilution and boost levels". Proceedings of the Institution of Mechanical Engineers, Part D: Journal of Automobile Engineering 233, nr 7 (1.08.2018): 1834–50. http://dx.doi.org/10.1177/0954407018790176.
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Because fuel efficiency is significantly affected by the timing of combustion in internal combustion engines, accurate control of combustion phasing is critical. In this paper, a nonlinear combustion phasing model is introduced and calibrated, and both a feedforward model–based control strategy and an adaptive model–based control strategy are investigated for combustion phasing control. The combustion phasing model combines a knock integral model, burn duration model, and a Wiebe function to predict the combustion phasing of a diesel engine. This model is simplified to be more suitable for combustion phasing control and is calibrated and validated using simulations and experimental data that include conditions with high exhaust gas recirculation fractions and high boost levels. Based on this model, an adaptive nonlinear model–based controller is designed for closed-loop control, and a feedforward model–based controller is designed for open-loop control. These two control approaches were tested in simulations. The simulation results show that during transient changes, the CA50 (the crank angle at which 50% of the mass of fuel has burned) can reach steady state in no more than five cycles and the steady-state errors are less than ±0.1 crank angle degree for adaptive control and less than ±0.5 crank angle degree for feedforward model–based control.
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Dunne, Julian F., i Colin Bennett. "A crank-kinematics-based engine cylinder pressure reconstruction model". International Journal of Engine Research 21, nr 7 (16.10.2019): 1147–61. http://dx.doi.org/10.1177/1468087419881869.
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A new inverse model is proposed for reconstructing steady-state and transient engine cylinder pressure using measured crank kinematics. An adaptive nonlinear time-dependent relationship is assumed between windowed-subsections of cylinder pressure and measured crank kinematics in a time-domain format (rather than in crank-angle domain). This relationship comprises a linear sum of four separate nonlinear functions of crank jerk, acceleration, velocity and crank angle. Each of these four nonlinear functions is obtained at each time instant by fitting separate m-term Chebyshev polynomial expansions, where the total 4 m instantaneous expansion coefficients are found using a standard (overdetermined) linear least-square solution method. A convergence check on the calibration accuracy shows that this initially improves as more Chebyshev polynomial terms are used, but with further increase, the overdetermined system becomes singular. Optimal accuracy Chebyshev expansions are found to be of degree m = 4, using 90 or more cycles of engine data to fit the model. To confirm the model accuracy in predictive mode, a defined measure is used, namely the ‘ calibration peak pressure error’. This measure allows effective a priori exclusion of occasionally unacceptable predictions. The method is tested using varying speed data taken from a three-cylinder direct-injection spark ignition engine fitted with cylinder pressure sensors and a high-resolution shaft encoder. Using appropriately filtered crank kinematics (plus the ‘calibration peak pressure error’), the model produces fast and accurate predictions for previously unseen data. Peak pressure predictions are consistently within 6.5% of target, whereas locations of peak pressure are consistently within ±2.7 °CA. The computational efficiency makes it very suitable for real-time implementation.
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Guo, Peng Jiang, Xi Yan Gao i Yun Bang Tang. "Analysis of Combustion Characteristics and Influencing Factors of Space Dispersed Double-Wall-Jet Combustion System". Advanced Materials Research 308-310 (sierpień 2011): 1302–13. http://dx.doi.org/10.4028/www.scientific.net/amr.308-310.1302.
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Based on the ideas of wall-guiding-spray and spatial dispersion, A new type of diesel engine double-wall-jet combustion system is designed. The effect of speed, load and injection condition on the double-wall-jet combustion system is researched by testing, on the double-wall-jet combustion system, the combustion modes for whole working condition is analyzed, the comparison of combustion and performance between the original machine with the new one is carried out. The results showed that: Instantaneous heat release rate of double-wall-jet combustion system shows a single peak. As the speed increases, the corresponding crank angle of ignition retards, the peak outbreak pressure increases and then decreases, the peak instantaneous heat release rate, the peak average temperature, the peak cylinder pressure rise ratio, and the cumulative heat release per unit mass of working gas is reduced. As the load increases, the corresponding crank angles of peak cylinder pressure and gravity center of heat release rate are postponed. With the load increasing, the ignition crank angle corresponds early at low speed, and the ignition point does not change significantly with the load at high speed. The effect of the injector hole diameter/number on the cylinder pressure and instantaneous heat release rate curve is not significant at high speed and large loads, but at low speed and large loads is significant. Cylinder pressure of 6-Φ21 injector is higher than 5-Φ25, the instantaneous heat release rate of 6-Φ21 injector has a trend of a single peak, the instantaneous heat release rate of 5-Φ25 injector has a trend of a double peak and the focus of the heat release rate postponed. With the advancing of injection timing, the ignition crank angle and combustion phase advances, the peak cylinder pressure increases. Injection pressure has little effect on the combustion characteristics. By comparison with the original machine, while maintaining the power performance of the same circumstances, the cylinder pressure and NOx emissions of double-wall-jet engine are reduced in degree, fuel consumption rate is not almost changed, and the same plane rather, smoke intensity is improved at low speed, smoke intensity at high speed smoke high-speed only deteriorates of 0.2-0.3 BSU.
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Bessot, Nicolas. "Effects of pedal rate and power output on cycling kinematics". Movement & Sport Sciences - Science & Motricité, nr 101 (2018): 23–31. http://dx.doi.org/10.1051/sm/2018011.
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The aim of this study was to examine the effect of changes in pedal rate and power output in the cycling kinematics of endurance cyclists. Nine male competitive cyclists performed 16 submaximal effort trials of 4 minutes’ duration on a cycle ergometer. Power output was imposed at 50, 100, 150, and 200 W successively for each pedal rate studied (45, 70, 95, 120 rev · min−1). The ankle, knee and hip flexion/extension, and pedal angle (pedal axis/malleolus medialis compared to the horizontal) were analysed. We observed an increase of mean pedal angle and a decrease of magnitude in pedal mobilisation when pedal rate increased or power output decreased. The mean pedal angle recorded during a crank cycle seems to depend on pedal load (power/pedal rate ratio). The supposed effect of pedal rate, power and pedal load on pedal angle was confirmed by adjusting a sin function (with pedal rate, power and power/pedal rate ratio as variables) representing the evolution of pedal angle during the crank evolution to experimental data. The modifications due to power and pedal rate change that were observed in pedal kinematics were generally transferred to the upper joints of the legs.