FEEG3002 Vehicle Powertrain, Noise and Vibration
Driven by both, legislation and consumer demand, automotive vehicle manufacturers have achieved considerable reductions in internal and external noise in recent decades. Key to understanding such advances and targeting future efforts is an appreciation of the contributions of the various noise sources and their dependence on operating conditions. This module provides an overview of noise sources in a vehicle and how they can be reduced or mitigated against. The powertrain (engine, clutch, gearbox, drive shaft and differential) is a predominant source of noise and vibration in some conditions and is considered here in some detail. The origins of powertrain related dynamic forces are examined and design principles are discussed for minimizing them both at source and in transmission to the vehicle.
Aims and Objectives
The aim of this module is to gain an understanding of powertrain related dynamic forces, how they can be reduced both at source and through the transmission path to the vehicle, and how they combine with other noise sources to determine overall interior and exterior noise.
Knowledge and Understanding
Having successfully completed this module, you will be able to demonstrate knowledge and understanding of:
- Understand noise transmission in a vehicle and recommend appropriate methods for noise control
- Understand how road roughness is quantified and used in simple vehicle models to predict road induced vibration
Subject Specific Practical Skills
Having successfully completed this module you will be able to:
- Calculate the basic loads imposed by gas-based and inertial forces in a multi-cylinder engine
- Employ measures to obtain partial or complete compensation for the inertial forces emanating from the crankshaft assembly
- Extract relevant information from an engine turning moment diagram in order to design a suitable flywheel
- Acquire skills in the design and analysis of gears and gear trains
- Become familiar with hydrokinetics powertrains and torque converters
- Implement and interpret simple physical models for vibration of a vehicle’s powertrain
- Create awareness of some of the quality issues related to the design of a luxury vehicle
Subject Specific Intellectual and Research Skills
Having successfully completed this module you will be able to:
- Basic design of a manual gearbox including the calculations of gear ratios, forces and toques
- Select powertrain mount properties to achieve required vibration isolation performance
- Discuss sources of noise in automotive vehicles and their characteristics
- Cite precise definitions of acoustic quantities and apply fundamental acoustic theory to predict them in a vehicle context
- Discuss the motivations for controlling noise and vibration in vehicles Appreciate some of the technical constraints and conflicts in designing a refined vehicle
Powertrain excitation Powertrain excitation: Review of balancing of rotating and reciprocating machinery Primary and secondary reciprocating forces and moments in multi-cylinder engines; Balancing methods Combustion forcing and torque fluctuations; Engine working loads, Turning-moment diagram and flywheel design, Friction clutch Power Transmission: Hydrokinetic drives: Fluid coupling and torque conversion, Torque-speed characteristics. Gears: Design and analysis, Simple, Compound, Epicyclic and differential gears. Automotive applications. Drive Trains: Design and Analysis, Planetary Gear Trains Basic design of a manual gearbox Powertrain and Chassis Vibration: Rigid body vibration, design criteria for mount system optimization, viscoelastic and hydro-elastic isolation mounts, source/receiver mobility models, transmission of powertrain vibration. Vehicle Noise: Fundamentals of acoustics: physical description and quantification of sound. Human response and sound quality. Motivation for noise control: legislation, quantitative analysis of the drive-by test. Noise sources: engine noise, intake and exhaust noise, tyre noise, wind noise. Airborne sound transmission: transmission loss through panels, materials for noise control. Structure-borne sound transmission: vibration isolation, damping. Experimental methods for noise path separation. Analysis of engine noise (e.g., engine order): processing of pre-recorded engine noise data. Assignment 1 (20%) Design of a Manual Gearbox Assignment 2 (0%) Powertrain vibration related assignment
Learning and Teaching
Teaching and learning methods
This is a one-semester module, the content of which is delivered predominantly through three one-hour lectures per week with one assignment to consolidate, expound upon and interlink topics covered in the lectures. The first assignment will involve basic analysis of a manual gearbox based on vehicle’s given specifications. The second assignment will involve processing of measured data from an engine mount and use of the results to predict rigid body powertrain vibration response. Tutorial sheets and solutions will be provided that cover quantitative examples in all four of the interconnected topic areas and one-to-one assistance and verbal feedback is facilitated through tutorial classes. Past exam papers will be available on Blackboard to aid personal study, feedback and revision.
|Practical classes and workshops||3|
|Completion of assessment task||35|
|Preparation for scheduled sessions||4|
|Total study time||150|
Resources & Reading list
T.D. Gillespie (1992). Fundamentals of Vehicle Dynamics.
S. Rao (1995). Mechanical Vibrations.
Naunheimer, H., Bertsche, B., Ryborz, J., Novak, W (2014). Automotive Transmissions: Fundamentals, Selection, Design and Application.
Holmes R. The Characteristics of Mechanical Engineering and Systems.
R.L. Norton. Design of Machinery: An Introduction to the Synthesis and Analysis of Mechanisms and Machines.
F.J. Fahy, J.G. Walker (1998). Fundamentals of Noise and Vibration, Chapter 7.
F.J. Fahy (2000). Foundations of Engineering Acoustics.
J.E. Shigley, J.J. Uicker (1995). Theory of machines and mechanisms.
|Exam (120 minutes)||80%|
|Exam (120 minutes)||100%|
Repeat type: Internal & External
Pre-requisite module/s: FEEG2002 Mechanics, Machines & Vibration.
To study this module, you will need to have studied the following module(s):
|FEEG2002||Mechanics, Machines & Vibration|