Transmission of vibrations from the engine to the car body

Measurement Science and Technology, 2002

This paper describes the application of a tracking laser Doppler vibrometer (TLDV) for vibration measurements on automotive components and the advances in data processing. A Lagrangian approach is adopted: the target point moves continuously and it is tracked by the measurement laser spot, thus no relative velocity between the target and the laser spot exists. By eliminating the relative motion of the laser beam on the surface, speckle noise is drastically reduced. Measuring on a moving reference frame opens an innovative way to look at automotive component vibrations, because the space-time evolution of the vibration can be measured under simulated operative conditions. After a presentation and discussion of the measurement technique, attention is focused on three different applications in the automotive field: the side-wall vibration of a rolling tyre, the out-of-plane vibration of a timing belt and the rubber blade vibration of complex motion windscreen wipers. The development of optimized TLDV measurement systems for each specific application is shown and some results are presented.

Journal of KONES, 2015

Fast development of technology over the last decades has contributed to the adverse effects that may affect human health (both physical and mental). Such negative effects may include noise and vibration. These phenomena are accompanied by most of the technological processes. Need for more efficient and productive processes is causing rising trend in intensifying of these phenomena. It is unavoidable to increase efficiency without increasing the operating speed of machinery and equipment. The main goal of this paper is to carry out NVH (noise, vibration and harshness) analysis of engines; compression-ignition engine (diesel) and spark-ignition engine (gasoline) equipped in the same type of vehicle. But purpose is laying on presented methodology, not results of researches (but of course it will be presented too) which often (mainly) is made for failure detections. This paper will also cover influence of the engine mounting on generated acoustic vibrations followed by comparative NVH analysis of states occurring in diesel and gasoline engine. Scope of the work: a) theoretical introduction, b) presentation of vibration measurement (using LDV: Laser Doppler Vibrometry), c) NVH analysis in two types of engines, d) comparison of results, e) conclusions.

2017 6th International Conference on Industrial Technology and Management (ICITM), 2017

In a vehicle production environment, obtaining information on the condition of the assembled vehicle, allows for increased quality while minimizing rework minutes at the same time. The cost of this information is associated with additional time in production, increasing the overall cost of the vehicle. The focus of this paper is development of a system for contactless measurement and investigation of vibrations present in the vehicle and the Rolling Road vehicle testing facility as a mean of identifying failures or degradation in the vehicle or testing facility. Measurements are performed using a contactless Laser Vibrometer based system which facilitates capturing the vibrations without interfering with the vehicle and other standard testing procedures. Signal conditioning and analysis methods are applied to measured vibration signals in an attempt to detect irregularities and determine their transient characteristics from the captured signals. Data analysis techniques employed in this initial trial of the system include Short Time Fourier and Wavelet Transforms. Proposed testing method including experimental setup, captured signals and some preliminary analysis results are discussed in this paper.

2007

The objective of this work is represented by a laser vibrometer application on a diesel engine for the identification of noise sources associated with its structural vibration. The first investigation has been concentrated on the possibility to identify as well as quantify the structural noise emissions of a direct injection diesel engine, used mainly for agricultural application as well as small off-road vehicles. In fact, the quantity of noise emitted by the structure represents a large part of overall noise level. The structural noise is directly, in fact, associated with the surface velocity of the engine structure and/or of its components and for this reason is very important to correlate the vibration and acoustic analyses. Through the use of a scanner laser vibrometer (mod. PSV400 Polytec), the vibration maps have been determined of the four accessible investigated surfaces around the engine (according to the standard ISO 3744). In particular, a set of 48 scanning data have b...

IOP Conference Series: Materials Science and Engineering, 2020

The aim of the research is to improve knowledge about the behaviour of materials and structures, to develop models and tools useful in the process of design of structures and machines and to capitalize on a technical culture in terms of analysis, design and manufacturing methodologies. We also set out to show the influence of which types of vibrations have an effect on the operation of the crankshaft mechanism of a car engine, as well as their influence on the operation of the camshaft system, all of which are taken into account in any design process in this field. The generalization of the theory of elasticity and the dynamics of viscous fluids led to the creation of the linear theory of viscos-elasticity, the bodies with such a behaviour obeying the principle of overlapping Boltzmann. Thus, mechanical models were built consisting of spring and damping systems, the springs describing the elastic properties of the body, and the dampers on the viscous ones.

Journal of Sound and Vibration, 2000

This paper builds on a previous study of the velocity sensed by a single laser vibrometer beam incident on a target in an arbitrary direction to predict the velocity sensed by multiple laser beams with arbitrary orientations. The usefulness of parallel beam arrangements is demonstrated and a concise new theory for the di!erence velocity sensitivity for two parallel beams is presented. Parallel beam arrangements for virtually unambiguous measurement of torsional vibration are presented along with arrangements that allow measurement of the pitch and yaw vibration to be derived. Resolution of individual pitch and yaw motions is shown not to be possible by any geometrical arrangement of the beams but a post-processing technique that enables the genuine pitch and yaw vibrations to be estimated from the measurements of the pitch and yaw vibration sets is demonstrated and validated experimentally in the laboratory. Measurements of pitch and yaw vibration are, for the "rst time, obtained from the crank-shaft of a running diesel engine, enabling identi"cation of the "rst natural frequency of the crank-shaft in bending.

Production Engineering Archives, 2017

There are several methods of automotive diagnostics used in services to detect a large variety of faults and damages of various parts of engines of internal combustion. Undoubtedly, they are effective, but they are simply unable to find all types of mechanical faults occurring during the operation. This is the reason why authors of this paper tried to use a special tool, which has been proven for years for detecting faults of rolling element bearing in rotating machinery. During their research, the authors tried to find valuable results by measuring vibration of various parts of engines. Three items were tested, a Diesel engine and two Otto motors. A large number of measurements have been taken at various speed, at different points, in different directions, with different parameter setup, etc. However, there was one setup which has been applied to all three engines. It is the measurement setup of vibration velocity, in the frequency range of 2 Hz-300 Hz. Valuable consequences have b...

SAE Technical Paper Series, 2013

The problems of vibration and noise from an internal combustion engine are common because of the wide variety of parts and components that make up an internal combustion engine. In recent years engines have evolved considerably in relation to the control of vibration and noise emitted, since these effects reduce the useful life of the internal components of the engine itself and, besides giving discomfort to the occupants of the vehicle. The objective of this work was to identify and describe the main sources of vibration and noise in an internal combustion engine. The methodology used in this work involved instrumentation of an internal combustion engine (Otto cycle), the experimental tests of the engine on a test bench and involved the application of analytical techniques for treatment and analysis of experimental data.

In automobile industry, the vibrations generated in the IC engine affects the performance of the vehicle and quality of comfort while riding the vehicle. The factors which are affected under continuous vibration of IC engine are drivability, stability and comfort. All these factors are reducing while there is an increase in vibrations produced by the engine. Reciprocating as well as rotating parts of the engine are producing vibrations continuously in the internal combustion engine. The inertial forces are produced by these reciprocating and rotating parts. These inertial forces are changing with compression and combustion characteristics inside the engine. The vibrations produced by the engine can be minimized by reducing those unbalanced forces generated during its functioning, otherwise anti vibration mounts are placed in between engine and its base. Many researchers have performed experimentations to see reasons behind the vibration generations also to reduce vibrations at interface between engine and its base. In this paper a thorough collection of data related to engine vibrations is made to provide a platform for future work. It encompasses various work carried on engine rigid body modeling. The paper is framed as engine rigid body modeling, engine vibrations in detail and at last some experimental work performed on a single cylinder diesel engine to measure vibrations using FFT spectrum analyzer.

n auto mobile industry, the vibrations generated in the IC engine affects the performance of the vehicle and quality of comfort while riding the vehicle . The factors which are affected under continuous vibrati on of IC engine are drivability, stability and comfort . All these factors are reducing while there is an increase in vi brations produced by the engine . Reciprocating as well as rotating parts of the engine are producing vibrations continuously in the internal combustion engine . The inertial forces are produced by these r eciprocating and rotating parts . These inertial forces are changing with compression and combustion characteristics inside the engine. The vibrations pro duced by the engine can be minimized by reducing those unbalanced forces g enerated during its functioning , otherwise anti vibration mounts are placed in between engine and its base. Many researchers have performed experimentations to see reasons behind the vibration generations also to reduce vibrations at interface between engine and its base. In this paper a thorough collection of data related to engine vibrations is made to provide a platform for future work. It encompasses various work carried on engine rigid body modeling . The paper is frame d as engine rigid body modeling , engine vibrations in detail and at last some experimental work performed on a single cylinder diesel engine to measure vibrations using FFT spectrum a nalyzer