[Active Engine Mounts]

by

Acknowledgement

I would take this opportunity to thank my research supervisor, family and friends for their support and guidance without which this research would not have been possible.

DECLARATION

I, [type your full first names and surname here], declare that the contents of this dissertation/thesis represent my own unaided work, and that the dissertation/thesis has not previously been submitted for academic examination towards any qualification. Furthermore, it represents my own opinions and not necessarily those of the University.

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Abstract

This paper is based on the topic of Engine Mount Modeling. The first chapter introduces the topic, followed by mathematical modeling for engine mounting in the second chapter. The third chapter is based on experimental design of the project. The fourth chapter is based on parameter identification, while the fifth chapter presents the simulation and validation system. The sixth chapter concludes the thesis, providing recommendations for future research.

Table of Contents

ABSTRACT4

CHAPTER 1 INTRODUCTION6

1.1 Desired Engine Mount Characteristics6

1.2 The Hydraulic Engine Mount6

1.3 Literature Review7

1.4 Objectives and Thesis Overview8

CHAPTER 2 MATHEMATICAL MODELING OF HYDRAULIC ENGINE MOUNTS9

2.1 Linear Model of a Typical Hydraulic Mount9

2.2 Mechanical System Model9

2.3 Mechanical System Model with a Bell10

2.4 Nonlinear Enhancement of the Bell Model11

2.5 Summary12

CHAPTER 3 EXPERIMENTAL DESIGN13

3.1 Goals and Approach13

3.2 Design Criteria14

3.3 Final Design14

3.4 Instrumentation15

3.5 Calibration15

3.6 Apparatus Capabilities16

CHAPTER 4 PARAMETER IDENTIFICATION17

4.1 Upper Chamber Compliance17

4.2 Lower Chamber Compliance17

4.3 Inertia Track Parameters18

4.4 Summary20

CHAPTER 5 SIMULATION AND VALIDATION OF SYSTEM MODELS22

5.1 Simulation Techniques22

5.2 Model Validation25

5.3 Summary26

CHAPTER 6 CONCLUSIONS AND RECOMMENDATIONS27

6.1 Conclusions27

6.2 Recommendations29

REFERENCES30

Chapter 1 Introduction

Automotive design encompasses many engineering disciplines and has captured the minds of many individuals. Using advanced technologies, the vehicles of today have been designed to represent a zone of comfort, handling, and driving pleasure. Extensive effort is focused on tuning the noise and vibration qualities to achieve the expected "feel" of a vehicle.

Reductions in body mass have increased engine-to-body weight ratios, which has raised the level of noise, vibration and harshness within vehicles. More sophisticated hydraulic mounts have been developed to address these issues. However, increased pressures to reduce vehicle development cost have forced engineers to develop these complex hydraulic mount systems in a limited time frame. The purpose of this work is to assist in reducing hydraulic mount development time by developing an effective hydraulic engine mount model and providing a physical explanation of internal dynamics.

1.1 Characteristics of the Engine Mount

Vehicle occupants receive undesirable vibrations through one of two possible excitation sources. The first source, from engine eccentricity, typically contains frequencies in the range of 25 to 200 Hz with amplitudes generally less than 0.3 mm. This frequency range corresponds to the required characteristics.

1.2 Engine Mount and Hydraulics

The passive hydraulic mount, illustrated in Figure 1.3, consists of two fluid-filled chambers connected through a decoupler and inertia track. Typically, the fluid within the mount is a mixture

Frequency Ratio (wdlwJ 3.5 4 (bj Figure 1.2: High frequency excitations: (a) SDOF forced input excitation; (b) transmitted force frequency domain plot. of ethylene glycol and water. The upper chamber is bound on top by the main ...