Rocker Arm Research Articles

Motion and Stress Analysis of Cam System for Marine Diesel Engine 93 KW

The developments of maritime sector in Indonesia shows increasing demand for ships. Especially ships with size of 30 GT has problem with low availability of the ship engine, which most of the ships still use non marine diesel engine as its main propulsion. The problem gives interest to make a step to improve by design marine diesel engine using reverse engineering method. Cam system of marine diesel engine design was needed to be calculate to select the material and the motion. The design of cam system needs study about the stress analysis in cam system to make sure the distribution of force and moment. The result of stress analysis was used to select material of components in cam system. The motion analysis result was used to be input data of stress analysis. The condition to obtain the stress of components was on maximum condition, its contain pressure, torque, rotation, and force. All component that calculated are camshaft, lifter (flat-tappet), push rod, rocker arm, spring, and valve. Each component was given two different materials and material selection was based on safety factor of each component. Material for camshaft and lifter were malleable cast iron, for push rod and rocker arm were mild steel, for spring was ASTM A231, for intake valve was steel JIS SUH3, and for exhaust valve was steel JIS SUH35. The result of motion analysis were angular velocity of camshaft with value was 2400 deg/sec, friction force between camshaft and lifter with maximum value was 125.393 N, and contact force between camshaft and lifter with maximum value was 845.307 N, and linear velocity of intake valve with maximum value was 696.573 mm/s, and linear velocity of exhaust valve was 463.734 mm/s.

Ergonomic evaluation of conventional agricultural sprayerswith respect to human performance

Ergonomic intervention in spraying operation can provide a reasonable basis for recommendation on operating methods and improvement in operation for more output and safety. Two commercially available sprayers namely knapsack sprayer and rocker sprayer were evaluated with nine male subjects for the study. Age, weight and height of the selected subjects are 30.33±1.93 years, 68.33±9.51 kg and 168.51±5.55 cm respectively. The major operational parameters including pressure and lever arm distance of the sprayers were selected and optimized based on human performance. Heart beat rate and operating energy requirement for ergo refined knapsack and rocker arm sprayers were observed as 93-120 beats per minute, 97-120 beats per minute, and 18.86- 24.31 KJ min-1, 19.27-25.54 KJ min-1 respectively. The field evaluation results showed that ergo refined knapsack sprayer and ergo refined rocker sprayer reduced the energy expenditure by 7% and 8%, oxygen consumption as percentage of VO2 max by 19% and 23%, “HR results gave a reduction of 22% and 23%, ODR results gave a reduction by 4% and 5% and BPDS score indicated a reduction of 13% to 12% respectively from the conventional sprayers. The above results confirmed that the ergo refined sprayers provided better comfort and efficiency to the operator.

Simulation analysis of the EUSAMA Plus suspension testing method including the impact of the vehicle untested side

The work deals with the simulation analysis of the half car vehicle model parameters on the suspension testing results. The Matlab simulation software was used. The considered model parameters are involved with the shock absorber damping coefficient, the tire radial stiffness, the car width and the rocker arm length. The consistent vibrations of both test plates were considered. Both wheels of the car were subjected to identical vibration, with frequency changed similar to the EUSAMA Plus principle. The shock absorber damping coefficient (for several values of the car width and rocker arm length) was changed on one and both sides of the vehicle. The obtained results are essential for the new suspension testing algorithm (basing on the EUSAMA Plus principle), which will be the aim of the further author's work.

Analysis of a failed rocker arm shaft of a passenger car engine

This paper investigates the failure of a rocker arm shaft of a passenger car. The shaft failed by brittle fracture across one of the four holes supporting the shaft into the cylinder head. The running distance of the engine just before failure was 40,626km. Visual examinations of etched sections of the failed shaft and a new one revealed four distinct zones of darker etching appearance. These zones correspond to the four locations where the rocker arms fit the shaft.Microscopic observations of the failed shaft revealed that the four dark-etching areas are surface hardened zones of martensitic microstructure. Furthermore, scanning the microstructure along the failed shaft showed that the heat treatment was so mistakenly extended by excessive heating so that the structure of the shaft near the supporting holes contains considerable content of martensite phase. This conclusion has been confirmed by the results of hardness measurements along the surface of the shaft.Microscopic investigations of the failed shaft revealed the presence of microcracks close to the supporting holes. These cracks may have been induced in the shaft by the non-uniform cooling during quenching in the course of heat treatment, or may be nucleated by repeated loading during service. This premature failure has occurred by the rapid crack propagation because of the lower fracture toughness of the martensite.

An Improved Genetic Fuzzy Logic Control Method to Reduce the Enlargement of Coal Floor Deformation in Shearer Memory Cutting Process

In order to reduce the enlargement of coal floor deformation and the manual adjustment frequency of rocker arms, an improved approach through integration of improved genetic algorithm and fuzzy logic control (GFLC) method is proposed. The enlargement of coal floor deformation is analyzed and a model is built. Then, the framework of proposed approach is built. Moreover, the constituents of GA such as tangent function roulette wheel selection (Tan-RWS) selection, uniform crossover, and nonuniform mutation are employed to enhance the performance of GFLC. Finally, two simulation examples and an industrial application example are carried out and the results indicate that the proposed method is feasible and efficient.

Effects of holding time during pre-sintering and post-forging annealing on the microstructure and mechanical properties of Ti parts fabricated by powder compact forging

Hydride-dehydride (HDH) Ti powder was consolidated into fully dense parts of rocker arms for internal combustion engines by powder compact forging at 1350°C. The microstructure, tensile mechanical properties and fracture behavior of forged Ti parts were studied. It was found that fully dense forged Ti parts had a fine α lamellar structure, and increasing the holding time of the powder compact at 1350°C from zero to 5min and post-forging annealing at 550°C for 6h are two effective ways to improve the level of consolidation of the Ti parts by removing weakly bonded interparticle boundaries (IPBs), leading to a significant increase of their ductility. The former approach is a better way of improving the level of consolidation due to the fact that it does not cause significant microstructure coarsening and clear decrease of tensile strength of the Ti parts. The correlation between the yield strength of the forged Ti parts without and with annealing and their average α-Ti lamellar thickness shows that it follows the Hall–Petch relationship, and the sensitivity of the yield strength of α-Ti to the average lamellar thickness is clearly higher than its sensitivity to the average size of equiaxed grains.

Shaping the Strength of Cast Rocker Arm for Special Purpose Vehicle

Abstract The article discusses the weldment to casting conversion process of rocker arm designed for operation in a special purpose vehicle to obtain a consistency of objective functions, which assume the reduced weight of component, the reduced maximum effort of material under the impact of service loads achieved through topology modification for optimum strength distribution in the sensitive areas, and the development of rocker arm manufacturing technology. As a result of conducted studies, the unit weight of the item was reduced by 25%, and the stress limit values were reduced to a level guaranteeing safe application.

Experimental Assessment of Ball Joints Operation Using Servo-Hydraulic Testing Systems

The paper reports experimental results from tests carried out at room temperature on servo-hydraulic system dedicated for examination of the exploitation properties of rocker arms. The ball joint of this element was modified by an application of composite coating such as the tungsten carbide (WC). To apply cyclic loading to rocker arms the griping system was designed and elaborated. Results from tests performed on the composite coated ball joints were compared with data obtained for typical elements. Variations of the following parameters versus time i.e. force, temperature and surface topography of balls were analysed with respect to exploitation properties of the modified ball joints. An increase of the wear coefficient was achieved for sliding joints of the steel ball-steel cups coated by the WC.

English

This is part two of the paper on conceptual design of an engine valve. The previous paper describes the background and the need of an engine valve for an internal combustion engine. The present state of the engine valve technology and the innovations incorporated in its design has been described. This paper presents the conceptualization of an innovative valve train aiming at lesser number of components, reduction in friction and wear, proper sealing, and trimming down pumping losses. Various geometric designs of valve trains have been detailed and compared. Finally a convolution based poppet valve mechanism, which is free from numerous mechanical elements like camshaft, cam, push rod, rocker arm and rocker bearing has been recommended. Finite element analysis of convoluted spring has been carried out to ascertain safe limits in terms of stresses and achieving desirable valve lift. Magnetorheological fluid and electromagnet are used to vary the valve-lift.

Assessment of a Jack-Up Offshore Launching Through Model Tests and Field Measurements

Recently, an experimental campaign was carried out to assess the feasibility of the launching operation of two jack-up units using a barge as the launching platform. This experimental study was divided in four stages. In stages 1 to 3, a series of preliminary model tests were performed in order to provide scientific understanding of the mechanics of the operation and investigate systematically the influence of launching parameters. The experimental approach developed for testing this operation and the results of the preliminary launching tests have already been discussed in detail. Based on the analyses of the experimental results of stages 1 to 3 and the results of numerical simulation tools in stage 4, a final launching condition was designed and a new set of model tests was specified to check the safety of the operation. This paper presents the results and analyses of the experimental tests of stage 4. The conditions tested in this stage covered the expected real launching condition and possible deviations in some launch parameters. The tests results include the 6 degree-of-freedom (DOF) motions and trajectories of the launched jack-up and the launch barge, and the reaction forces on the barge rocker arms. Later on, the success of the launching operations of P-59 and P-60 jack-up units confirmed the experimental investigation results and the feasibility of this novel launching procedure. During the launching of unit P-60, field measurements were performed that confirmed that model tests as an efficient tool for the assessment of high risk operations.

Cascaded Nonlinear Control of a Duocopter with Disturbance Compensation by an Unscented Kalman Filter

A cascaded control strategy for an innovative Duocopter test rig - a helicopter with two rotors combined with a guiding mechanism - is presented in this paper. The guiding mechanism consists of a rocker arm with a sliding carriage that enforces a planar workspace of the Duocopter. The Duocopter is attached to the carriage by a rotary joint and offers 3 degrees of freedom. The derived system model has similarities with a PVTOL and a planar model of a quadrocopter but involves additional terms due to the guiding mechanism. In the paper, a model-based cascaded control strategy is proposed: in the outer MIMO control loop, sliding mode techniques are employed to control both the horizontal and the vertical Duocopter position. The rotation angle of the Duocopter is controlled in a linear inner control loop using flatness-based techniques. An additional feedforward control takes into account known parts of the coupling forces between the carriage and the rocker. The control structure is extended by an Unscented Kalman Filter (UKF) that provides estimates for the state vector and, moreover, estimates for remaining errors concerning the feedforward coupling forces. The sum of the feedforward part and the estimated part can be used to accurately compensate for the impact of the guiding mechanism on the motion of the Duocopter frame. Thereby, an excellent tracking performance in vertical and horizontal direction can be achieved. The efficiency of the proposed control strategy is demonstrated by experiments.

Using Polymers as the Main Material in Engine Blocks and Components

A substance which has a Molecular structure built up chiefly or completely from a large number of similar units bonded together, e.g. many synthetic organic materials used as plastics and resins. Plastics are very often used to quickly develop models in the automotive industry. A plastic prototype of a rocker arm can be created with 24 hours whereas a full metal model would take up to months and cost several times greater than then the plastic model. Rapid prototyping cuts the time factor in a manufacturing environment significantly and when time is cut so is the cost. The last and most important thing about plastics is that they are extremely recyclable. They are much easier to recycle than typical metals

A New Numerical Method for Developing the Lumped Dynamic Model of Valve Train

The dynamics of valve train is influenced by stiffness, size, and mass distribution of its components and initial valve clearance and so on. All the factors should be taken into consideration correctly by dynamic model and described qualitatively and quantitatively through mathematical variables. This paper proposes a new simplified method for valve train components, namely, mode matching method (MMM) for camshaft, pushrod, rocker arm, valve, and valve spring. In this method, the amount of lumped masses for each flexible component is determined based on its natural frequencies and the considered frequency range. As a result, the dynamic model of each component is required to match its low order modes within the considered frequency range. The basis of this method is that the contributions of each component to valve train vibration are mainly in the low order modes. The numerical model of valve train is verified by an experiment conducted on a motor driven valve train system.

Densification Behavior and Microstructure Evolution of LTCC Film Constrained by Rigid Substrate

LTCC films constrained by rigid substrate were sintered at different temperatures ranging from 760 °C to 800 °C. An optical dilatometer together with a rocking arm was employed to record sintering strains of the constrained films during the sintering process. The densification behavior of constrained films was systematically studied through the measured sintering strains by comparing with that of freely sintered films. For the constrained films, the final density was smaller and the activation energy for the densification was larger than that of the freely sintered ones. Moreover, anisotropic microstructure was induced by the tensile stress.

Synthesis and kinematic and dynamic analysis of a variable valve lift mechanism with general contact curve

In this paper, a new type of continuously variable valve lift (VVL) system is presented. The mechanism comprises a standard roller finger follower, the camshaft, and an intermediate rocker arm used between them. When the adjustment shaft rotates, the intermediate rocker arm is repositioned with respect to the cam and the roller of the rocker finger. This means that, when the rotation angle of the adjustment shaft is controlled, the valve lift height is also controlled. The intermediate rocker arm is equipped with a special developed contact surface, which is one of the novelties of this paper. The profile of the contact surface is analytically determined using the theory of the envelope curves. Using a certain cam profile, the kinematic analysis of the mechanism proceeds, resulting in the family of the valve lift laws. This paper also establishes the general conditions to design a variable valve timing (VVT) mechanism with continuous VVL and mechanical actuation. Numerical simulation shows that the mechanism continuously varies valve lift height and timing phases, while the valve’s opening time remains constant. The last parts of the paper are dedicated to different aspects concerning the elastohydrodynamic lubrication and valve train dynamics. The study is performed by comparing the optimized cam and a standard harmonic one which achieves the same maximum displacement of the valve. The optimized cam ensures better safety in functioning, a smaller preload, leading to a greater oil film thickness, and not causing excessive deformations in the engine. The calculation model is a general one, and it may be applied to other mechanisms with similar configuration.

Nonlinear Aeroelastic Analysis for a Rudder with a Hydraulic Booster

Nonlinear aeroelastic characteristics of a rudder with a hydraulic booster are investigated, including the structural nonlinearity and dynamics of the hydraulic booster. The component mode substitution method is used to establish the nonlinear governing equations based on the fundamental dynamic equations of the hydraulic booster and rocker arm. Simulations are carried out when the control command is not zero and further analysis is conducted when the freeplay angle is changed. The results show that the effects of the actuator and the structural nonlinearity have a significant influence on the flutter characteristics. In the nonlinear condition, the phase and frequency of the control command have both an influence on the flutter characteristics.

An Experimental Approach for the Offshore Launching of Jack-Ups

Recently, as part of the building contract for the new Brazilian jack-up drilling platforms, an operational challenge was raised: to launch these units from the building site, where neither dry dock nor launching ground ways exist. Economically, the best alternative was to launch these jack-ups using the available barges used commonly for jacket launch. Due to the marked differences between a jacket and a jack-up, the implementation of this novel launch operation required a careful feasibility study. Model tests were required to measure the motions of the barge and the jack-up and to evaluate the loads on the barge rocker arms. The present paper discusses the experimental approach, test setup, calibration procedures, and some results from the hydrodynamics perspective.

Design Manufacturing and Cost Estimation of Camshaft Used In Two Wheeler

The camshaft and its associated parts control the opening and closing of the two valves. The associated parts are push rods, rocker arms, valve springs and tappets. This shaft also provides the drive to the ignition system. The camshaft is driven by the crankshaft through timing gears. Cams are made as integral parts of the camshaft and are designed in such a way to open the valves at the correct timing and to keep them open for the necessary duration. In this project, a camshaft is designed for a two wheeler engine by using theoretical calculations. Cam profile is designed by using the calculations. A 3D model of the Camshaft is created using modeling software Pro/Engineer. For manufacturing cam shaft following manufacturing method are used by Machining, Casting and Forging. From above processes we selected casting processes because it’s used for bulk production. For the manufacture of Camshaft Core and Cavity is to be extracted from the model using manufacturing module in Pro/Engineer. Total Mould base is to be designed for the camshaft which is ready to go for production. CNC Program is to be generated for both core and cavity using roughing and finishing processes. This is also done in manufacturing module in Pro/Engineer. Total cost required for the manufacturing of die is estimated. From this project we will learn a manufacturing method for camshaft. Pro/ENGINEER is the standard in 3D product design, featuring industry-leading productivity tools that promote best practices in design.

A New Approach to Calculating Feeder Size and Location with Simulation Software

A new approach of feeder calculation was introduced in this paper. By using the simulation software, the feeder size and location can be calculated easily and test by run simulation, the results can be seen directly. Take the rocker arm as an example, the method was introduced by using SOLIDCast.

Static Strength Analysis of Components of Flap Control System for a Certain Type of Aircraft

Pull rod and rocker arm are important parts of aircraft control system, its strength, stiffness and stability can largely affect the aircrafts control effect, sometimes the flight safety will be influenced [2]. A type of aircraft control system has been upgraded and modified, therefore the pull rod and rocker arm of the flap control system need to take the static strength test. Based on field test and finite element simulation analysis, this paper has the static strength of pull rod and rocker arm checked, and to verify the correctness of the finite element model and lay foundation for the optimization design of components of aircraft control system.