Crank Pin Research Articles

Couple Stress Effects on the Dynamic Behavior of Connecting Rod Bearings in Both Gasoline and Diesel Engines

An isothermal hydrodynamic analysis of big end connecting rod bearings for both diesel and gasoline engines lubricated with couple stress fluids is undertaken. Based on the V. K. Stokes micro-continuum theory, an incompressible modified Reynolds equation is derived from the fluid motion and mass conservation equations using the assumptions of thin-film theory. The hydrodynamic performance and the crank pin center trajectories are determined numerically by means of the Booker mobility technique. Compared with the Newtonian lubricant case, the lubricants with couple stresses provide an increase of the minimum film thickness, and a drastic decrease of the power loss, peak pressure, and flow rate over one engine cycle for both engines.

OS-A3: An extended expansion stroke using multiple linkage system in general purpose engine(OS-A High Efficiency and Low Emission Engine by Variable Mechanism,Organized Session Papers)

Research has been conducted on an extended expansion engine, using a multiple linkage system to increase the thermal efficiency of general-purpose engines. A four jointed linkage was used between the connecting rod and the crank pin of a standard piston-crank system. The end of the linkage rotates at half the speed of the crankshaft, resulting in piston strokes unequal length in each revolution. The length of the expansion stroke is greater than that of the compression stroke, thereby providing an extended expansion cycle.

Optimizing parameters of complexly loaded friction bearings

Crankshaft rod bearings of a combustion engine are used as an example to show the technique and results of optimization of the design parameters of friction bearing under a complex load. The field of hydrodynamic pressures in a lubricating layer, which separates the crank pin and the bearing lining, is determined by integrating the equation for filling of the gap. This approach ensures observance of the condition of lubricant continuity at the boundaries of discontinuity and restoration of the lubricating layer. The lubricant viscosity, which is assumed to be an effective function of the temperature of the lubricating layer, is adjusted at each step of the calculation of the crank pin’s motion trajectory.

Dynamic analysis of a slider–crank mechanism with eccentric connector and planetary gears

In this study, the kinematic and dynamic analysis of a modified slider–crank mechanism which has an additional eccentric link between connecting rod and crank pin, as distinct from a conventional mechanism, are presented. This new extra link that may be called the eccentric connector transmits gas forces to the crank, and it also drives a planetary gear mechanism transmitting a great deal of driving forces to the output. In order to drive the planetary gear train, a pinion fixed to the eccentric connector is used. Consequently, the driving force is transmitted to crankshaft by means of two different ways. For the comparison, the dynamic analysis results of developed slider–crank mechanism have been evaluated with respect to that of a conventional slider–crank mechanism. As a result, although both the conventional and the modified slider–crank mechanisms have the same stroke and the same gas pressure in the cylinder, it is observed that the modified mechanism has a bigger output torque than that of the conventional mechanism.

Design of neural networks model for transmission angle of a modified mechanism

This paper discusses Neural Networks as predictor for analyzing of transmission angle of slider-crank mechanism. There are different types of neural network algorithms obtained by using chain rules. The neural network is a feedforward neural network. On the other hand, the slider-crank mechanism is a modified mechanism by using an additional link between connecting rod and crank pin. Through extensive simulations, these neural network models are shown to be effective for prediction and analyzing of a modified slider-crank mechanism’s transmission angle.

Analysis of tool wear and surface finish in hard turning

Hard turning is a profitable alternative to finish grinding. The ultimate aim of hard turning is to remove work piece material in a single cut rather than a lengthy grinding operation in order to reduce processing time, production cost, surface roughness, and setup time, and to remain competitive. In recent years, interrupted hard turning, which is the process of turning hardened parts with areas of interrupted surfaces, has also been encouraged. The process of hard turning offers many potential benefits compared to the conventional grinding operation. Additionally, tool wear, tool life, quality of surface turned, and amount of material removed are also predicted. In this analysis, 18 different machining conditions, with three different grades of polycrystalline cubic boron nitride (PCBN), cutting tool are considered. This paper describes the various characteristics in terms of component quality, tool life, tool wear, effects of individual parameters on tool life and material removal, and economics of operation. The newer solution, a hard turning operation, is performed on a lathe. In this study, the PCBN tool inserts are used with a WIDAX PT GNR 2525 M16 tool holder. The hardened material selected for hard turning is commercially available engine crank pin material.

低速ディーゼルエンジン用組立型クランク軸の高強度鋳鋼材料の開発及びクランク軸の応力評価と応力測定

High strength cast steel, Throw Grade 5, has been developed for semi-built-up crankshafts to cover all current types of low speed diesel engines. Material test results with test pieces taken from a full-scale crankthrow are reported. Manufacturing approvals for this material have been taken from major classification societies. Prior to the application of this cast steel to an actual crankshaft, the crank pin fillet stresses at several points were measured in the workshop. The dynamic stress of each point, as analyzed with the finite element method, corresponds well with the measured data. Finally, application of this material to the crankshaft of an engine in a severe vibratory condition is introduced to show effective use of the material.

Improving kinematic and structural performance of Geneva mechanisms using the optimal control method

A method is proposed to improve the performance of the conventional Geneva mechanism. Rather than driving the input crank at a uniform speed, this method uses optimal control theory to synthesize the speed of the crank. In this paper, design criteria are first developed based upon the elimination of the impact loading at the beginning and end of the motion cycle. In addition, three approaches to program the crank speed are introduced. In the first approach, the crank speed is designed to be optimal so as to minimize the output acceleration. In the second approach, the crank speed is determined by minimizing the input motor torque. The third approach uses the degree of wear between the crank pin and wheel slot as the index to optimize the crank speed. All design objectives are formulated as a parameterized optimization problem and solved via an efficient numerical method. Furthermore, trade-offs among the desired characteristics are taken into account by formulating the problem as a multiobjective optimization problem. Two examples are given to illustrate the design procedure.

Crankshaft Analysis of Strain Distribution Generated by the Influence of Bending and Torsional Vibration in Operation.

One of the main parts of the diesel engine, the crankshaft has the important items related with noise, vibration, and durability. The precise prediction as to these items will be, therefore, useful for understanding the vibration mechanism and for improving these items in an early design stage. This paper describes a new method of predicting these items in operation, by means of several techniques in consideration of the non-linearity in the oil film stiffness and exciting force, applied to the V6 type crankshaft. The accuracy of the simulation is demonstrated by comparing the calculated results with the actual vibration. The visualized simulation results are analytically cleared that the strain at the crank pin fillet is increased by the bending vibration coupled with the torsional vibration.

Prediction of Crank Pin Journal Temperature Based on the Oil Flow Rate.

Prediction of Crank Pin Journal Temperature Based on the Oil Flow Rate.

Analysis of the Influence of Crankshaft System Vibrations on the Crankshaft Bending Stresses in a V-10 Diesel Engine. 2nd Report. Crankshaft Stresses Induced by Gyroscopic Vibrations of the Crankshaft System.

The three-dimensional vibrations of a crankshat system were calculated using the dynamic stiffness matrix method taking into account gyroscopic effects. The dynamic bending stresses at fillets of the No.1 crank journal and the No.1 crank pin were measured. From the experimental and calculated results we found that: (1) the maximum bending stresses are caused by bending vibrations coupled with torsional vibrations, and the second largest bending stresses are induced by bending vibrations caused by the mass-elastic system of the torsional damper about the axis orthogonal to the No.1 crank throw plane and by gyroscopic vibrations of the inertia ring of the torsional damper; (2) forward whirl and reverse whirl of the crankshaft are induced in a crankshaft system with gyroscopic vibrations. With forward whirl, the center of the crankshaft front end traces an elliptical locus in the same direction as that of crankshaft rotation, whereas the direction is reversed with reverse whirl.

Stress Analyses of the Big End of Diagonally Split Connecting Rod. Shapes of Serrations.

The big end of a connecting rod of medium-speed diesel engines is frequently diagonally split to reduce its width to enable easy assembly and disassembly. Accordingly, shearing forces occur along the interface between the shank and cap. To support these shearing forces, serrations which have shapes similar to screw threads are machined at both contact surfaces. It is reported that failure is sometimes observed around serrations, which seems to be caused by stress concentrations at the root of serrations and the relative displacement between mating surfaces. In this study, the strength of serrations subjected to basic loading, such as compression, shear and bending, is analyzed by FEM which deals with elastic contact problems, where the effects of the configuration of serration, pitch errors of the serration occurring during machining and coefficients of friction at contact surfaces are estimated. In addition, the effects of the distance between the serration and the blind hole in which a crank pin bolt is tapped, are also discussed by employing the axisymmetric model.

New method of crankshaft design for high speed diesel engines : Ito, M., Himokouchi, H., Arakawa, H., Numata, A. and Kajimoto, K. Mitsubishi Juko Giho (1993) 30 (6), 531–534 (in Japanese)

In this work the failure analysis of the crankshaft of diesel engine was performed. Visual examination of the crankshaft fracture showed that beach marks, typical for fatigue failure were observed. Additional observations of the crack initiation zone indicated that crack origin was not covered by material defects or corrosion products. Performed hardness test of the fractured crank pin showed that large HRC values were observed in central part of the pin only. On the corner of cylindrical pin surface where the crack origin was located the hardness of material was much smaller. In order to explain the reason of premature crankshaft damage, the finite element method was utilized. The results of nonlinear static analysis showed that during work of the engine with maximum power the high stress area was located in crack initiation zone. Based on results of performed investigations it was concluded that the main reason of premature fatigue failure was high-cycle fatigue of the material in external zone of the crank pin where the small structural radius was designed. In final part of the work the recommendations for increase of the fatigue life of analyzed crankshaft were formulated.

Device and method for altering the acoustic signature of an internal combustion engine

An apparatus and method for altering the acoustic signature of an internal combustion engine is disclosed. Several techniques for altering the acoustic signature of an engine are shown, including time-varying, disabling or cutout of individual cylinders of an engine in a random fashion in order to reduce the periodic characteristics of the exhaust noise of the engine. Alternate embodiments include offsetting crank pins to transform an even firing engine into an uneven firing engine, inhibiting the fueling of individual cylinders, and inhibiting the ignition signals provided to individual cylinders. A combination of the above techniques may also be implemented in order to disperse the exhaust noise energy present over a wide frequency range, making acoustic detection of the exhaust signature difficult. Cylinder cutout schemes are implemented over a single or multiple engine cycle to disperse exhaust noise pulses over time and randomize measurable spectral noise composition.

Tin alloy coating of aluminium bearings by brush plating

To meet the growing requirements for higher performance internal combustion engines, high strength, light aluminium alloy crank pin bearings are required to be plated with lead-tin, lead-tin-copper or lead-indium overlays. To achieve good adhesion the conventional zincate plus nickel strike route is employed. However, there is some evidence that nickel has undesirable seizure properties, and it would, therefore, be beneficial if it could be eliminated from the product. The objective of this work was to devise an improved plating process taking account of this problem

Plasma nitriding improvements of fatigue properties of nodular cast iron crankshafts

Crankshafts of the pearlitic-sorbitic nodular cast iron type JUS NL.80 (similar to DIN GGG-80) heat treated to get a tensile strength of 820–900 GPa ( i.e. a Vickers hardness of 268–295 HV) were plasma and ammonia gas nitrided. The glow discharge plasma nitriding was performed for 20 h at about 500 °C in a gas mixture of 55% N 2 and 45% H 2. The gas nitriding was performed for 28 h at 510 °C in the ammonia gas. Evaluation of the nitrided surfaces was conducted by optical microscopy, X-ray diffractometry and microhardness measurements. Journal and crank pin dimensions and surface roughness were measured both before and after nitriding. Bending fatigue testing of crankshafts was performedv using a fatigue testing rig. The fatigue limit was evaluated at 5.0 × 10 6 cycles. The fractures happened at the transition radius of the journal with cracks starting beneath the nitrided layer. It was found that the nitrided crankshafts had 18% higher dynamical strength in relation to the unnitrided crankshafts. In this respect, no differences were found between plasma- and gas-nitrided crankshafts. The changes in the surface roughness and journal and crank pin diameters after plasma nitriding can be well controlled. In this respect, plasma nitriding gave better results than ammonia gas nitriding.

Study on the Vibration and Strength of the Long Stroke Diesel Engine Crank Shaftings

A calculation method, by which suitable vibration and strength estimation for crank shaftings of recent 2-stroke cycle marine diesel engine can be obtained is desired, because other methods proposed before have difficulties in application for such type engines. Theoretical analysis as well as full scale measurement has been carried out in The Research Institute of Nippon Kaiji Kyokai, and as a result, a new analysis system has been developed. The system is composed mainly of a free vibration analysis routine, a forced vibration analysis routine and a crank pin fillet strain calculation routine. Evaluation of crank throw stiffness by FEM calculation, a new determination method of crank exciting force, calculation of crank pin fillet strain with a new concept response factor which is determined by FEM zooming calculation, are newly introduced. One can analyse torsional, axial and coupled torsional-axial vibration of shafting system and get pin fillet strain wave form including added components induced by the vibration. Calculation results show good agreement with measured ones.

Study on the Vibration and Strength of the Long Stroke Diesel Engine Crank Shaftings

Following the previous report which proposed a new calculation model for crank shaftings of the long stroke marine diesel engine and an evaluation method for the stiffness of crank throws, a calculation method for the coupled axial-torsional forced vibration is presented in this report. In the method, conversion of the crank pin force into the equivalent axial force is newly introduced. Moreover, accurate axial-torsional vibration measurements were carried out during both shop and sea trials. Minute analysis on the test results revealed the mechanism of the vibration.Calculation results by the new method show fairly good agreement with the measured ones only except for higher harmonics oscillation at the resonance of 1-node torsional vibration, which is recognized to be caused by non-linearity of the thrust block stiffness.

Design of Spherical Drag-Links Between Positions of Unity Velocity Ratio

While synthesizing a planar drag-link between positions of unity velocity can be reduced to a problem of synthesizing a planar crank-rocker, this is not the case with a spherical drag-link. Synthesis equations for designing spherical drag-links between positions of unit velocity ratio are derived from equations previously obtained for matching two prescribed velocity ratios. It has been shown that the loci of both crank pins are spherical ellipses and great circles. An example is given.

重油中の触媒残さによる機関摩耗について

FCC slurry bottom oil and FCC cycle oil are getting used as base stock for making a marine heavy fuel even in Japan. The marine heavy fuel which contains FCC slurry bottom oil and FCC cycle oil contains small quantity of catalyst fines, because it can not be recovered completely by a catalyst reclaimer. The catalyst fines in a fuel oil are very abrasive ones and wear engine parts such as piston rings, a cylinder liner and parts of a fuel injection pump.But, few data concerned with the relation between catalyst fines and engine wear have been presented, specially the quantitative relations. Therefore, influence of catalyst fines on engine wear has been investigated by the engine tests with the heavy fuels contained known quantities of catalyst fines.The five kinds of heavy fuels which contain catalyst fines of 0, 30, 60, 100 and 150 ppm, were prepared for the engine tests. The engine test of 30 hour duration was carried out for each fuel.Main items measured included the wears of piston rings, a cylinder liner, crank-pin metals, a plunger, a barrel, a delivery valve and a needle valve, and Fe and n-pentane insoluble contents in lubricant.From the test results, the followings are concluded.1. Piston ring and cylinder liner wears increase in proportion to an increase of catalyst fines content in a fuel oil.2. In the case of a trunk piston type engine, Fe and n-pentane insoluble contents in lubricant increase in proportion to an increase of catalyst fines content in a fuel oil, and crank pin metal wear increases consequently.