Engine Vibration Research Articles

Experimental Study Results Processing Method for the Marine Diesel Engines Vibration Activity Caused by the Cylinder-Piston Group Operations

The article discusses the method and results of processing statistical data from an experimental study of vibrations in marine diesel engines caused by the operation of cylinder-piston groups. The results of the application of a ranking method for identifying factors that influence vibration in marine diesel engines are presented to determine the most significant ones. A series of experiments were conducted according to special plans to actively implement the random balance method. This helped to establish the correctness of selecting the most significant factors from a variety of factors that influence the process under study. The article presents a mathematical model that enables the calculation of current values and prediction of changes in the most significant indicators, with the clearance between the piston and the cylinder liner being the most important.

Особливості розроблення піроболтів з низькими ударними та віброімпульсними характеристиками

One of the systems in the integrated launch vehicle responsible for prelaunch processing and launch is a ground thermal conditioning system, which supplies the low-pressure air into the launch vehicle’s “dry” compartments. Thermal conditioning system is mated with the launch vehicle, using the mating interfaces, proper functioning of which enhances reliability of the ground support equipment, the launch vehicle and the entire space launch system. The article describes key requirements to the interfaces of the thermal conditioning system and the drawbacks of the existing designs. The article proposes a new design concept of the interface that connects the pipeline of the ground thermal conditioning system to the orifice of the launch vehicle using the corrugated rubber hose composed of three basic parts, attached with the help of a metal lock/release assembly. The proposed solution provides reliable leaktightness, ease of operation, providing multiple connections to the launch vehicle, including at various angles, and automatic disconnection by rocket motion or manual removal in case of launch abort. Using rubber as a high-elasticity structural material to manufacture the hoses, enabled minimization of efforts required to disconnect the interface from the launch vehicle. In its high-elasticity state, rubber can absorb and dissipate mechanical energy within a wide range of temperatures, which prevents transmission of engine vibrations to the ground thermal conditioning system. The article presents key properties of rubber used as a structural material and its peculiarities to be considered during design of similar products. Unlike metal showing two types of deformation (elastic and plastic), rubber can exhibit three types of deformation (elastic, superelastic and plastic). In the process of interface design, we took into account two types of deformations (elastic and superelastic ones). Experimental studies of the interface showed its full compliance with technical specification. Key words: orifice of the launch vehicle, corrugated rubber hose, lock/release assembly, superelastic deformation, leaktightness.

Methods to Reduce the Noise and Vibration of Engine

Abstract: Engine vibration and noise are crucial features that impact a vehicle's overall driving experience. The purpose of this research paper is to look into methods for reducing an engine's noise and vibration levels. The research looks at a number of methods, including dynamic balance, material selection, and design analysis. A noise level and a vibration analyzer were used to measure the engine's noise and vibration levels. The results showed that by putting these methods into action, levels of noise and vibration were significantly reduced.

How Do Microalgae Biodiesel Blends Affect the Acoustic and Vibration Characteristics of the Direct Injection Diesel Engine: An Experimental Examination

Abstract The noise and vibration characteristics play a vital role in the effectiveness of engine operations and performance of internal combustion engines. Accumulation of the higher amplitude of both noise and vibration affects the comfort of the engine. So far, most of the research done on the performance, combustion, and emission characteristics only. Less importance is shown in the form engine vibration and sounds created by the engine operation. This paper presents and explores the importance and experimental results of noise and vibration by the compression ignition diesel engine with the fuels of diesel and microalgae biodiesel. The produced microalgae biodiesel blends were SMB10%, SMB20%, and SMB30%. The experimental results were conducted at different engine loads varying across 25%, 50%, 75%, and 100%. The inline, four-cylinder, water-cooled, and naturally aspirated DI diesel engine was used as an experimental setup. From the comparative results between the diesel and microalgae biodiesel, it is found that the use of microalgae blended biodiesel reduced the noise and vibration. The higher the percentage of blends, the greater the reduction in sound and vibration will be. Apart from possessing the performance and emission qualities, the microalgae biodiesel blends proved to be an efficient fuel in reduced vibration and noise qualities too. In three directions, the vibrations were measured as lateral, longitudinal, and vertical vibrations. The vibration in the lateral direction was significantly reduced. Compelling the results, it is understood that the use of the microalgae blends can be sustainable from the perspective of engine wear and tear.

Productivity analysis focusing on internal combustion engine vibration when using local fuels and additives

The purpose of this article is to analyze the vibrations and behavior of an internal combustion engine of three vehicles: A1, J1, K1 which are exposed to both the geography, relief and road conditions of the Metropolitan District of Quito. To implement the quantitative methodology in the research it is important to perform a complete analysis of the vehicle based on its technical data sheet: A1, J1, K1, in order to identify both fuel consumption and the use of additives to reduce the friction that cause vibrations in the engine, especially the condition of the road. In addition, it is important to check how the level of vibrations can be reduced, the percentage of fuel when using additives and to verify the data provided by the vibration study of each vehicle. The results show that the tests carried out at 3500 RPM in vehicle A1 show a value of 27%, in vehicle J1 a value of 17% and vehicle K1 a value of 15%, these values are related to the use of additives. The results of the research are linked to field tests, individual tests, comparison of results and discussion of the feasibility of each of the tests performed on each vehicle to find similarities or marked differences.

Investigation of exhaust emissions and performance of a diesel engine fueled with preheated raw grape seed oil/propanol blends

The enrichment of alternative fuels with oxygen in diesel engines is one of the influential techniques utilized to improve performance and lower emissions. This work analyzed the influences of grape seed oil-propanol fuel mixture, which can be an alternative to diesel fuel, on diesel engine. Grape seed oil (GSO), which was used raw, was extracted from grape seeds by cold pressing method. In order to improve physical and chemical attributes of fuel mixtures, preheating process was applied. The engine tests were realized in an air cooled single cylinder diesel engine. GSO was stirred with diesel fuel in volumes of 10% and 30% and also 5% propanol was added. In this study, CO, NOX, smoke, HC, BSFC, EGT, BTE, vibration and noise parameters of diesel engine were taken into consideration. Moreover, thermal images of the engine were also recorded. The results indicated that BSFC, CO, smoke and HC diminished but NOX, BTE, EGT, vibration and noise increased in the preheated and propanol added test fuels. Preheating process for grape seed oil ensured a convenient fuel flow and decreased the oil viscosity and propanol addition contributed to the enrichment of the fuel in terms of oxygen.

A High-Temperature Accelerometer with Excellent Performance Based on the Improved Graphene Aerogel.

A high-temperature accelerometer plays an important role for ensuring normal operation of equipment in aerospace, such as monitoring and identifying abnormal vibrations of aircraft engines. Phase transitions of piezoelectric crystals, mechanical failure and current leakage of piezoresistive/capacitive materials are the prominent inherent limitations of present high-temperature accelerometers working continuously above 973 K. With the rapid development of aerospace, it is a great challenge to develop a new type of vibration sensor to meet the crucial demands at high temperature. Here we report a high-temperature accelerometer working with a contact resistance mechanism. Based on the improved graphene aerogel (GA) prepared by a modulated treatment process, the accelerometer can operate continuously and stably at 1073 K and intermittently at 1273 K. The developed sensor is lightweight (sensitive element <5 mg) and has high sensitivity (an order of magnitude higher than MEMS accelerometers) and wide frequency response range (up to 5 kHz at 1073 K) with marked stability, repeatability and low nonlinearity error (<1%). These merits are attributed to the excellent and stable mechanical properties of the improved GA in the range of 299-1073 K. The accelerometer could be a promising candidate for high-temperature vibration sensing in space stations, planetary rovers and others.

Modeling and Measuring of Relative Motion at Contact Point of Electrical Connector for the Prediction of Vibration-Induced Fretting Damage

The relative motion at the contact interface induced by engine vibration is one of the most significant causes for the fretting damage. However, at present, several vibration simulations models have been investigated in literature to predict fretting degradation. Unfortunately, those finite element (FE) models do not take into account all the connector components (more than 10) with the cable, the non-linear mechanical contact and the prestress state of different components after assembled process. This paper describes and illustrates the approaches used for a three-dimensional FE modeling and vibration simulation of electrical connector to evaluate the relative displacement between the terminals at contact point, and when the fretting occurs. A series of experimental tests were also conducted to validate the simulation. A sinusoidal vibration with a single frequency and amplitude were applied to the connector system. It was demonstrated that, test and simulation presented similar results. Finally, an approach for predicting connector risk of fretting damage is established by combining the contacts endurance and relative motion at contact point and eventually quantify the threshold amplitude of fretting.

Intake Manifold Material Selection and Fluid Flow Analysis for Formula Society of Automotive Engineers (FSAE) Race Car

The Formula SAE competition is organised for students who want to design and build a Formula-style race car. To limit the car's performance for safety and to encourage problem-solving skills, a 20mm restrictor was installed between the carburetor and the intake manifold to reduce air intake. When airflow is restricted, a bottleneck effect occurs, and less air is supplied to the engine for combustion, lowering engine efficiency. The goal of this project is to find a solution to this problem within the rules' limitations. This is accomplished by selecting an intake manifold that provides the best uniform distribution through each outlet and selecting a material that can withstand engine stress and vibrations while maintaining a relatively low temperature to ensure consistent velocity and pressure. Computational Fluid Dynamics (CFD) software is used to analyse the design's fluid flow, static, and thermal analysis, and the results are compared for each design. The best design and material will be used on the Universiti Malaysia Perlis Automotive Racing Team (UniART) race car

Project-based learning goes wrong: the trials, tribulations, and triumphs of managing first-year and fourth-year engineering projects

Project-based learning (PBL) has many advantages for both students and instructors. The students are afforded the opportunity to work on self-driven, meaningful projects that model engineering problems they may see in their future careers. For the instructor, PBL emphasizes problem-solving strategies, requires students to learn relevant technical skills through self-study, underscores the importance of team work, and encourages student buy-in. However, PBL techniques present their own sorts of difficulties, especially when applied in large courses of 50 + students. For example, an instructor must strike a balance between fostering creativity and enthusiasm, while also keeping students on task and focused on the purpose of the project. Managing many small groups or a few large groups can be logistically challenging due to the sheer number of unique projects and students involved. This presentation will focus on two engineering courses, first-year introduction to engineering and fourth-year vibrations, in which project-based learning was employed with partial success. In these courses, there were logistic complications, issues with team dynamics, and problems with final presentations that can hopefully serve as good lessons (or warnings) for others interested in developing project-based courses.

EVALUATION OF VIBRATION AND NOISE CHARACTERISTICS OF A COMPRESSION-IGNITION ENGINE FUELLED WITH NATURAL GAS-BIODIESEL DUAL FUEL

As environmental requirements become more stringent and the planet becomes more polluted, the replacement of conventional diesel is attracting more interest. For alternative fuels, such as biodiesel and natural gas, to be used, their effects must be examined not only in terms of the engine’s environmental indicators but also in terms of engine vibrations and sound pressure. This study examined the influence of dual fuel – biodiesel and natural gas – on vibrations and sound pressure of a compression-ignition (CI) engine. Conventional diesel or hydrotreated vegetable oil biodiesel was used as a pilot fuel for gas ignition. The gaseous fuel was natural gas, which was injected into the intake manifold with different energy shares of the gaseous fuel (40%, 60% and 80%). Tests were performed at a constant engine crankshaft speed and a fixed start of pilot fuel injection of 6° BTDC while the fuel composition and engine load were changed. This experiment revealed correlations between gas energy share (GES) in liquid fuel and ecological and energy indicators of a CI engine.

Lightweight intelligent engine vibration prediction model with small samples

Lightweight intelligent engine vibration prediction model with small samples

Mirror-assisted multi-view high-speed digital image correlation for dual-surface dynamic deformation measurement

Based on the recently proposed mirror-assisted multi-view digital image correlation (MV-DIC), we establish a cost-effective and easy-to-implement mirror-assisted multi-view high-speed digital image correlation (MVHS-DIC) method and explore its applications for dual-surface full-field dynamic deformation measurement. In contrast to the general requirement of four expensive high-speed cameras for dual-surface dynamic deformation field measurement, the established mirror-assisted MVHS-DIC halves the cost by involving only two synchronized high-speed cameras and two planar mirrors. The two synchronized highspeed cameras can dynamically measure the front and rear surfaces of a sheet sample simultaneously through the reflection of the two mirrors The results on the two surfaces are then transformed into the same coordinate system, leading to the required dual-surface 3D dynamical deformation fields. The effectiveness and accuracy of the established system are validated through modal tests of a cantilever aluminum sheet. The vibration measurement of a drum and dual-surface transient deformation measurement of a smartphone in the drop-collision process further prove its practicability. Benefiting from the attractive advantages of multiview dynamic deformation measurement in a cost-efficient way, the established mirror-assisted MVHS-DIC is expected to encourage more comprehensive dynamic mechanical behavior characterization of regular-sized materials and structures in vibration and impact engineering fields.

Determining the Influence of a Magnetic Field on the Vibration and Fuel Consumption of a Heavy Diesel Engine

Most of the fuels used in internal combustion engines are liquid fuels. The magnetic behavior of fuel leads to a change in the interaction of hydrocarbon and oxygen molecules. This study aimed to evaluate the fuel consumption and engine vibration (time domain) of the Perkins A63544 diesel engine using magnetized fuel. The vibration of an internal combustion engine can cause failure in engine components and discomfort and injury to users. Engine vibration behavior changes due to changes in fuel types and engine combustion. Therefore, in this study, the vibration behavior of the tractor engine (Perkins model, four-stroke, direct injection diesel) was evaluated in stationary mode at different engine speeds due to changes in fuel types. Three accelerometers (CTC AC102 model) were used to measure the vibration acceleration. The fuels used included diesel as a normal control and fuels that had been subjected to magnetic field intensities of 1000, 2000, 3000, and 4000 gauss. The longitudinal, vertical, and lateral vibration signals with 5 levels of engine speed were measured. The results illustrated that the vibration root mean square (RMS) values were essentially (p &lt; 0.01) affected by the engine speed, fuel type, and their interactions. It was found that for the 4000-gauss magnetized fuel, the average vibration acceleration using the five velocity settings reduced by 15%, 15.30%, 12.40%, 12.35%, and 15.38% compared to the respective control fuels. The results showed that engine fuel consumption and specific fuel consumption decreased by 2.3% using the 4000-gauss magnetized fuel compared with the normal control fuel.

Research on Structure Design and Control Method of Magnetorheological Suspension Based on Improved Fruit Fly Optimization Algorithm

To reduce engine vibration, a semi-active controlled magnetorheological suspension is designed. First, the magnetic circuit of the new magnetorheological suspension is simulated. Furthermore, the non-parametric forward and inverse dynamic models of the magnetorheological suspension with the Elman neural network are established, where the modeling results and accuracy are analyzed. Second, according to the characteristics of semi-active vibration control of engine suspension, an improved fruit fly optimized proportional-integral-differential (PID) controller is proposed. Compared with the original fruit fly optimized PID controller and particle swarm optimization PID controller, the control strategies based on the proposed methods are simulated by MATLAB. Then, a vibration control experiment is carried out under different control strategies. The simulation and experiment results show that the PID controller based on the improved fruit fly optimization algorithm has the advantages of short adjustment time and fast dynamic response.

Effect of vibration and pressure on the air-bioCNG mixture inside the manifolds of dual-fuel diesel engines

Abstract The vibration generated by diesel engines may influence air and gaseous fuel mixing in dual-fuel mode. This study is performed on the manifolds of single and twin-cylinder engines in diesel-bioCNG dual-fuel mode. It examines the effect of the engine vibration and variable manifold pressure on the flow behaviour of the air-bioCNG mixture. The objective is to observe the flow inside the manifolds and mixture quality at the outlet. The mentioned work has found little attention till date. The computational comparison of the flow characteristics inside the intake manifold of the single-cylinder engine is done for an F-shape manifold of the twin-cylinder engine during suction stroke. The experiments are conducted to record both the engines' vibration signature and cycle data. For this, the same operating parameters are maintained: compression ratio of 16.5, engine speed of 1500 rpm, engine load range (0 Nm to 34 Nm) and 80% bioCNG substitution. It employs the boundary conditions, such as the vibration amplitude along three axes, variable manifold pressure, and the mass flow rates of air and bioCNG. The parameters to analyse the mixture flow are pressure, velocity, turbulence, helicity and mass fraction of CH4. The mixture at the manifold outlet of the single-cylinder engine improved to average uniformity index of 0.9924, indicating better homogeneity. Further, the manifold of twin-cylinder engine attained the indexes of 0.1484 and 0.2401 for its two cylinders, showing non-homogeneity.

Robustness analysis of magnetorheological elastomer-based vibration isolation system with optimal fuzzy controller

Due to adjustable stuffiness with applied magnetic fields, magnetorheological elastomer (MRE)-based vibration isolation method has attracted more attention in vibration engineering fields, such as precision-fabrication or precision-measurement platform for high-tech facilities, civil structure. However, there exists parameter uncertainty in dynamic model of control system, such as variation load mass in different working conditions, increasing or decreasing stiffness due to the rubber aging induced by the temperature and humidity of the environment. So it is necessary to investigate and evaluate quantitatively the robustness of MRE-based vibration isolation control system. This paper addresses that. Firstly, the dynamic model of MRE vibration isolation system with consideration of uncertain stiffness of the isolator and load mass is established. Then, a fuzzy controller (FC) is designed under the certain amplitude and frequency excitation, the parameters of FC are optimized by genetic algorithm. On this basis, RI (robustness index) is proposed to divide the robustness of the system under variation of parameters (stiffness of MRE isolator and load mass) as ‘good’, ‘fair’ and ‘poor’ level. Lastly, simulation and experiments are carried out to evaluate quantitatively the robustness performance of MRE vibration control system with designed optimal FC, respectively. The results show that the designed optimal FC has greater RI than experienced-based FC for different variation range stiffness of MRE isolator and load mass, and demonstrates outstanding robustness.

Numerical investigation of power flow input into a fuselage due to jet engine induced wing vibrations

The wings of passenger aircrafts are constantly vibrating due to various loads. There are transient low-frequency vibrations caused by gust loads. But there are also higher-frequency vibrations caused by the vibration load of the jet engines. The higher-frequency stationary vibrations of the wing are partially introduced as a power flow into the fuselage and radiated there as sound, which is then perceived as noise. In this work, which is part of the EU CleanSky2 framework, this chain of effects is being investigated in more detail aiming for the quantification of the vibrational power flow input into the fuselage by utilizing structural intensity. In this paper, numerical investigations are carried out on FEM models of an Airbus A320 wing generated with a parametric model generator. First, the structural components mainly responsible for the power transmission are identified, and second, the magnitude of the power input into the fuselage is determined in dependence of the pylon position along the wing. The engine vibrations are approximated by a custom-developed model. In the further course of the project, these numerical results will be validated by a test campaign. For this purpose, a real wing of an A320 is available as a test structure.

High-resolution vibro-acoustic measurement and analysis of the DLR ISTAR aircraft to assess engine-induced cabin noise

Aircraft engines, especially when mounted directly to the fuselage, inject a considerable amount of tonal vibrations into the airframe causing audible and comfort reducing cabin noise. Reducing this noise requires the development of specialised noise reduction systems. This is a time consuming and expensive endeavour. To speed up and ease this process a sufficiently detailed numerical model of the aircraft structure and the force injected by the engines is required. The DLR ISTAR, a Dassault Falcon 2000, was used for an extensive vibration measurement campaign. The goal of this campaign was twofold: Getting spatially dense information about the aircrafts vibro-acoustic behaviour to later update a finite element model for calculations in the mid-frequency range and to analyse the vibration injected by running engines into the fuselage structure. The measurements include the vibrational response to both shaker excitation and engine vibration of the DLR ISTAR at about 1400 positions acquired by a rowing grid of sensors. The results are presented in the form of operational deflection shapes and energy transfer paths calculated using structural intensity analysis.

Multi-Objective Optimization Design Method for Whole-Aeroengine Coupling Vibration

With the increasing thrust-to-weight ratio of modern aeroengines and the widespread adoption of thin-walled casing, the impact of the coupling vibration effect between the rotor and stator on the critical speed, rotor–stator mode shape coordination, and response characteristics of the whole engine have become increasingly prominent. However, the vibrational design of the whole-engine coupling has thus far relied on human experience, revealing a need for the study of its intelligent optimization. In this study, to quantitatively analyze the vibration of the whole engine, three vibration evaluation indexes were defined, which were risk coefficients for the critical speed, rotor strain energy, and cross-section rotor–stator rubbing. Using these indexes as the optimization targets, a multi-objective intelligent optimization design method for aeroengine support stiffness was proposed. The design optimization of the support stiffness of a turbofan engine with a large bypass ratio was performed. The results showed that the vibration index of the whole machine can be reduced to different degrees and that the whole-engine coupling vibration is optimized.