The Analysis for the Influence of Engine Excitation on the Dynamical Behavior of Motor Vehicle

2012 ◽  
Vol 197 ◽  
pp. 179-184
Author(s):  
Li Xing Sun ◽  
Ge Qun Shu
Keyword(s):  
Dynamic Behavior ◽  
Dynamic Simulation ◽  
Motor Vehicle ◽  
Dynamical Behavior ◽  
Valve Train ◽  
Vertical Acceleration ◽  
Lumped Mass ◽  
Engine Model ◽  
Motorcycle Frame ◽  
Engine Excitation

In the multibody dynamics analysis for motor vehicle, engine excitation, as a major excitation affecting the dynamic behavior of motorcycle frame, should be discussed. In this paper, a real-sized virtual engine model is established to replace lumped mass sphere ever discussed in dynamic simulation of vehicle, on which elaborate dynamic simulation of the valve train in engine is conducted at working condition to investigate the dynamic response of frame. The vertical acceleration response of the frame is achieved by using solution formulations set in professional program, and the comparison is discussed between different simulation results of frame dynamic behavior with or without engine excitation to determine the significance of dynamic simulation with considering the interaction between excitation and mechanism which is then utilized to discuss the vibration and smoothness performance of whole mechanical system.

Investigation of an OHC Valve Train With Respect to Sound Quality

1995 ◽  
Author(s):  
In-Soo Suh ◽  
Sophie Debost
Keyword(s):  
Dynamic Behavior ◽  
High Speed ◽  
Transfer Functions ◽  
Sound Quality ◽  
Valve Train ◽  
Subjective Response ◽  
Frequency Range ◽  
Lumped Mass ◽  
Mass Model ◽  
Resonance Frequencies

Abstract Although the vibration generated by high speed dynamic movement of a valve train (VT) in an overhead camshaft SI engine is not a major source of engine noise, it still affects the overall sound quality of the engine, which is important to the subjective response of the customer. The purpose of this research is to determine the specific mechanism of the valve train dynamic behavior, which is responsible for noise generation, and the vibration transmission characteristic to engine surfaces. Dynamic simulation with a lumped mass model is developed to analyze the dynamic behavior of VT during operation, and reveal the resonance frequencies of VT modeshapes excited by the cam harmonics. Also, experimental measurements of the valve acceleration, transfer functions of vibration, and the structural response have been performed in the valve train rig. Based on the spectral analysis, two distinct noise generating mechanisms are determined. Vibration from VT components’ interaction, which is mainly excited by the harmonics of the cam profile during valve opening period, is dominant in the frequency range less than 6 kHz. On the other hand, valve seating is the dominant source in the frequency range from 6 kHz to 20 kHz. The more vibration energy from these two sources is transmitted through the structure via the VT system, rather than directly via the valve seat to the surfaces where sound is radiated, especially around the frequency of 5 kHz and 11 kHz. This fundamental investigation on the vibration sources and its transmission characteristics provides a new insight on the VT noise, which is an essential step toward the design of an engine with better sound quality.

Dynamic analysis of a helical gear reduction by experimental and numerical methods

2020 ◽  
Vol 68 (1) ◽  
pp. 48-58
Author(s):  
Chao Liu ◽  
Zongde Fang ◽  
Fang Guo ◽  
Long Xiang ◽  
Yabin Guan ◽  
...  
Keyword(s):  
Numerical Methods ◽  
Dynamic Analysis ◽  
Dynamic Behavior ◽  
Fourth Order ◽  
Numerical Models ◽  
Helical Gear ◽  
Operating Conditions ◽  
Dynamic Responses ◽  
Lumped Mass ◽  
Gear Mesh

Presented in this study is investigation of dynamic behavior of a helical gear reduction by experimental and numerical methods. A closed-loop test rig is designed to measure vibrations of the example system, and the basic principle as well as relevant signal processing method is introduced. A hybrid user-defined element model is established to predict relative vibration acceleration at the gear mesh in a direction normal to contact surfaces. The other two numerical models are also constructed by lumped mass method and contact FEM to compare with the previous model in terms of dynamic responses of the system. First, the experiment data demonstrate that the loaded transmission error calculated by LTCA method is generally acceptable and that the assumption ignoring the tooth backlash is valid under the conditions of large loads. Second, under the common operating conditions, the system vibrations obtained by the experimental and numerical methods primarily occur at the first fourth-order meshing frequencies and that the maximum vibration amplitude, for each method, appears on the fourth-order meshing frequency. Moreover, root-mean-square (RMS) value of the acceleration increases with the increasing loads. Finally, according to the comparison of the simulation results, the variation tendencies of the RMS value along with input rotational speed agree well and that the frequencies where the resonances occur keep coincident generally. With summaries of merit and demerit, application of each numerical method is suggested for dynamic analysis of cylindrical gear system, which aids designers for desirable dynamic behavior of the system and better solutions to engineering problems.

Dynamic Behavior of Aircraft Wings Modeled as Doubly-Tapered Composite Thin-Walled Beams

1999 ◽  
Author(s):  
Sungsoo Na ◽  
Liviu Librescu
Keyword(s):  
Composite Materials ◽  
Free Vibration ◽  
Dynamic Response ◽  
Dynamic Behavior ◽  
Transverse Shear ◽  
Dynamical Behavior ◽  
Time Dependent ◽  
Aircraft Wings ◽  
Helicopter Blades ◽  
Thin Walled

Abstract A study of the dynamical behavior of aircraft wings modeled as doubly-tapered thin-walled beams, made from advanced anisotropic composite materials, and incorporating a number of non-classical effects such as transverse shear, and warping inhibition is presented. The supplied numerical results illustrate the effects played by the taper ratio, anisotropy of constituent materials, transverse shear flexibility, and warping inhibition on free vibration and dynamic response to time-dependent external excitations. Although considered for aircraft wings, this analysis and results can be also applied to a large number of structures such as helicopter blades, robotic manipulator arms, space booms, tall cantilever chimneys, etc.

Research on Dynamic Simulation of AUV Launching a Towed Navigation Buoyage

2013 ◽  
Vol 433-435 ◽  
pp. 1170-1174
Author(s):  
Guang Pan ◽  
Zhi Dong Yang ◽  
Xiao Xu Du
Keyword(s):  
Angular Momentum ◽  
Boundary Conditions ◽  
Dynamic Simulation ◽  
Numerical Scheme ◽  
Mathematic Model ◽  
Dynamic Equations ◽  
Lumped Mass ◽  
Lumped Mass Method ◽  
Towed Cable ◽  
Undersea Vehicle

A mathematic model was established to simulate the process of AUV (autonomous undersea vehicle) launching a towed buoyage. Based on the lumped mass method and moment theorem and angular momentum theorem, dynamic equations of the cable and the buoyage were developed, respectively. Then the boundary conditions and the numerical scheme to deal with the cable with non-fixed length were presented. Moreover, the process of AUV launching a towed cable was simulated. By using the model, the results show the trajectory of buoyage and shape of towed cable can be well predicted.

Identification of firefly algorithm-based fluctuation coefficient of the exciting torque for vehicle driveline

2018 ◽  
Vol 233 (2) ◽  
pp. 317-326
Author(s):  
Qiaobin Liu ◽  
Wenku Shi ◽  
Zhiyong Chen
Keyword(s):  
Torsional Vibration ◽  
Firefly Algorithm ◽  
Vibration Response ◽  
Theoretical Modelling ◽  
Lumped Mass ◽  
Mass Model ◽  
Engine Torque ◽  
Lumped Mass Model ◽  
Vibration Performance ◽  
Engine Excitation

The unbalanced excitation force and torque generated by an engine that resonate with the natural frequency of drivetrain often causes vibration and noise problems in vehicles. This study aims to comprehensively employ theoretical modelling and experimental identification methods to obtain the fluctuation coefficients of engine excitation torque when a car is in different gear positions. The inherent characteristics of the system are studied on the basis of the four-degree-of-freedom driveline lumped mass model and the longitudinal dynamics model of vehicle. The correctness of the model is verified by torsional vibration test. The second order's engine torque fluctuation coefficients are identified by firefly algorithm according to the curves of flywheel speed in different gears under the acceleration condition of the whole open throttle. The torque obtained by parameter identification is applied to the model, and the torsional vibration response of the system is analysed. The influence of the key parameters on the torsional vibration response of the system is investigated. The study concludes that proper reduction of clutch stiffness can increase clutch damping and half-axle rigidity, which can help improve the torsional vibration performance of the system. This study can provide reference for vehicle drivetrain modelling and torsional vibration control.

Dynamic Modeling of an Overhead Valve Engine CAM-Follower System Using a Resistive Companion Dynamic Simulation Solver

2005 ◽  
Author(s):  
Daniel C. Sloope ◽  
David N. Rocheleau
Keyword(s):  
Mathematical Model ◽  
Dynamic Simulation ◽  
Dynamic Modeling ◽  
Valve Train ◽  
Test Bed ◽  
Virtual Test ◽  
Virtual Test Bed ◽  
Cam Follower ◽  
Valve Engine ◽  
The Mathematical Model

A computer simulation model of the valve train of a Honda GX30 engine was modeled using Virtual Test Bed (VTB), a resistive companion dynamic simulation solver. Traditionally VTB has been exclusive to solving electrical system models but using the resistive companion equivalence of through and across variables, it can be applied to mechanical systems. This paper describes a dynamic simulation of an overhead valve engine cam-follower system using the VTB software application. The model was created to show valve train position, velocity and acceleration to aid in development of a camless engine being developed at the University of South Carolina. The mathematical model was created using governing dynamic equations. Using C++ programming, the mathematical model was transformed into a Virtual Test Bed model. The VTB model successfully shows valve train component position, velocity and acceleration. The significance of this work is its novelty in using the Virtual Test Bed environment to handle dynamic modeling of mechanical systems, whereas to date, VTB has been primarily focused on resistive companion modeling of power electronic systems. This work provides the foundation for using VTB to tackle more complex mechanical models.

scholarly journals Dynamic Simulation of Adiabatic Catalytic Fixed-Bed Tubular Reactors: A Simple Approximate Modeling Approach

2014 ◽  
Vol 14 (1) ◽  
pp. 25
Author(s):  
Wiwut Tanthapanichakoon ◽  
Shinichi Koda ◽  
Burin Khemthong
Keyword(s):  
Dynamic Model ◽  
Dynamic Behavior ◽  
Dynamic Simulation ◽  
Flow Rate ◽  
Fixed Bed ◽  
Axial Dispersion ◽  
Fixed Bed Reactor ◽  
Inlet Temperature ◽  
Acetylene Hydrogenation ◽  
Tubular Reactors

Fixed-bed tubular reactors are used widely in chemical process industries, for example, selective hydrogenation of acetylene to ethylene in a naphtha cracking plant. A dynamic model is required when the effect of large fluctuations with time in influent stream (temperature, pressure, flow rate, and/or composition) on the reactor performance is to be investigated or automatically controlled. To predict approximate dynamic behavior of adiabatic selective acetylene hydrogenation reactors, we proposed a simple 1-dimensional model based on residence time distribution (RTD) effect to represent the cases of plug flow without/with axial dispersion. By modeling the nonideal flow regimes as a number of CSTRs (completely stirred tank reactors) in series to give not only equivalent RTD effect but also theoretically the same dynamic behavior in the case of isothermal first-order reactions, the obtained simple dynamic model consists of a set of nonlinear ODEs (ordinary differential equations), which can simultaneously be integrated using Excel VBA (Visual BASIC Applications) and 4th-order Runge-Kutta algorithm. The effects of reactor inlet temperature, axial dispersion, and flow rate deviation on the dynamic behavior of the system were investigated. In addition, comparison of the simulated effects of flow rate deviation was made between two industrial-size reactors.Keywords: Dynamic simulation, 1-D model, Adiabatic reactor, Acetylene hydrogenation, Fixed-bed reactor, Axial dispersion effect

scholarly journals Hyperchaotic Oscillation in the Deformed Rikitake Two-Disc Dynamo System Induced by Memory Effect

Complexity ◽  
2020 ◽  
Vol 2020 ◽  
pp. 1-10 ◽  
Author(s):  
Yanling Wang ◽  
Tengfei Lei ◽  
Xin Zhang ◽  
Chunbiao Li ◽  
Sajad Jafari
Keyword(s):  
Bifurcation Diagram ◽  
Dynamic Behavior ◽  
Lyapunov Exponents ◽  
Memory Effect ◽  
Dynamical Behavior ◽  
Phase Portraits ◽  
Generator System

The fundamental dynamics of the deformed Rikitake two-disc dynamo system is explored in this paper. Memory effect on the dynamical behavior of the generator system is studied by introducing a quadratic flux-controlled memristor. Hyperchaotic oscillation in the deformed Rikitake two-disk coupled generator is therefore firstly found. Lyapunov exponents, bifurcation diagram, and phase portraits prove the abundant dynamic behavior consistently.

Dynamic Behavior Analysis of an Axially Loaded Beam Supported by a Nonlinear Spring-Mass System

2021 ◽  
pp. 2150152
Author(s):  
Yuhao Zhao ◽  
Jingtao Du
Keyword(s):  
Dynamic Behavior ◽  
Stable Steady State ◽  
Bernoulli Beam ◽  
Lumped Mass ◽  
Mass System ◽  
Nonlinear Spring ◽  
Periodic State ◽  
Galerkin Truncation ◽  
Axially Loaded ◽  
Euler Bernoulli Beam

Dynamic analysis of an Euler–Bernoulli beam with nonlinear supports is receiving greater research interest in recent years. Current studies usually consider the boundary and internal nonlinear supports separately, and the system rotational restraint is usually ignored. However, there is little study considering the simultaneous existence of axial load, lumped mass and internal supports for such nonlinear problem. Motivated by this limitation, the dynamic behavior of an axially loaded beam supported by a nonlinear spring-mass system is solved and investigated in this paper. Modal functions of an axially loaded Euler–Bernoulli beam with linear elastic supports are taken as trail functions in Galerkin discretization of the nonlinear governing differential equation. Stable steady-state response of such axially loaded beam supported by a nonlinear spring-mass system is solved via Galerkin truncation method, which is also validated by finite difference method. Results show that parameters of nonlinear spring-mass system and boundary condition have a significant influence on system dynamic behavior. Moreover, appropriate nonlinear parameters can switch the system behavior between the single-periodic state and quasi-periodic state effectively.

Dynamic Simulation of Road Vehicle Performance Under Transient Accelerating Conditions

1996 ◽  
Vol 210 (1) ◽  
pp. 11-21 ◽  
Author(s):  
C-W Hong
Keyword(s):  
Steady State ◽  
Dynamic Simulation ◽  
Thermal Inertia ◽  
Engine Performance ◽  
Reconstruction Method ◽  
Passenger Cars ◽  
Road Vehicle ◽  
Vehicle Performance ◽  
Inertia Effects ◽  
Engine Model

A personal computer-based simulation package has been developed to design the powertrain system of passenger cars aiming to operate at optimal performance. This package is capable of dynamic simulation of road vehicle performance under transient accelerating conditions. Two methods are included: one is the traditional transient-reconstruction method using steady-state engine performance maps; the other is a dynamic simulation technique newly developed by the author. The latter is described in this paper. It is based on cyclic analysis of the engine thermofluid-combustion phenomena with additional considerations of flow inertia, thermal inertia and mechanical inertia effects. This transient engine model plus a dynamic powertrain model and a transient road-load simulation make it possible to predict the automobile performance under road-driving conditions. Two examples of transient performance prediction, including a sudden full-throttle acceleration at a fixed gear and a changing-gear starting acceleration from standstill, are demonstrated in this paper. These examples show that the relation between the engine speed and the road speed under accelerating conditions is very different to the steady-state relationships normally assumed.

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