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P11221 - Noise Reduction for Internal Combustion Engines. Faculty Advisor : Ed Hanzlik Customer : Dr. Alan Nye. Team Leader : Christopher Morehouse Mechanical Engineers : - Julie Maier - Caroline Bills - Ted Zachwieja. Agenda. Problem Overview Project Objectives
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P11221 - Noise Reduction for Internal Combustion Engines Faculty Advisor: Ed Hanzlik Customer: Dr. Alan Nye Team Leader: Christopher Morehouse Mechanical Engineers: - Julie Maier - Caroline Bills - Ted Zachwieja
Agenda • Problem Overview • Project Objectives • Customers and Users • Project Flow Chart & Plan • Engine Model Overview • Design Options • Design Feasibility • Next Steps • Questions & Discussions
Background • Noise abatement - growing field • Formula SAE Sound Constraints • Conventional Methods Reduce Performance • No RIT Background in this Field • Multiple Applications Possible • Customer: Dr. Nye • Users: Formula SAE Team • EE 2010-2 Team
Project Scope • Investigate physics of sound generation and transmission • Identify and locate major noise contributors in ICE • Analyze and model noise generation of ICE • Propose design for noise reduction mechanism • Provide background to EE team for parallel ANC project • Provide noise reduction demonstrator for Spring 2011 ImagineRIT
Project Deliverables • Engine Sound Model • ANC System Constraints • Demonstrator for ImagineRIT
Relationship Diagram • ES 1 Reduce noise level • ES 4 Passes B10.2.1 of the SAE Formula rules • ES 7 Component Costs • ES 12 Change in Engine Max Power
Sound is Pressure http://www.school-for-champions.com/science/noise_cancellation.htm
How We Measure Sound • Digital Signal Processing • Decibel Meters • Sound Pressure Indicators
IC Engine Sources Pressure Waves
Current Design • Glass Pack • Low Flow Restriction • Low Noise Attenuation
Unpacked Concentric Tube Resonators • Design #1: Single-pass • Design #2: Multi-pass • Passive http://www.eastsidemufflers.com/mufflers.htm
Packed Concentric Tubes • Design #3: Metal Foam • Design #4: Full Length of the Exhaust System • Design #5: Rock Wool and Stainless Steel Wool www.stainlessworks.net
Designs #3 & #4: Metal Foams www.bundesregierung.de
Foams • Permeability • Pore Size • Level of Reticulation • Absorption Area • Length • Curves • Thickness • Scott Acoustical Laboratories
Foams www.bundesregierung.de
Optimal Foam Structure Industrial Noise Control Handbook. Cheremisinoff and Cheremisinoff
Absorption Area Industrial Noise Control Handbook. Cheremisinoff and Cheremisinoff
Metal Foams • Available in a variety of densities • Available in a variety of pore sizes • ERG Duocel • Test kit en route • Aluminum • Copper • Silicon Carbide • Reticulated Vitreous Carbon (RVC)
ERG Duocel Metal Foams ERGaerospace.com
Design #5: Rock Wool • A fibrous insulation made from basalt • Custom Muffler and Auto Repair, LA • Cone Engineering, Inc., CA • MagnaFlow Exhaust
Design #7: Exhaust Silencer Insert • Applied to exhaust tip • Reflects Sound Waves back into exhaust stream
Design #10: Active Noise Cancellation (ANC) This generates more sound by the adding of two waves.
ANC continued Introducing a wave 180 degrees out of phase of the targeted noise being cancelled.
How ANC Applies to Cars Three Major components of sound generation occur in a car Dominating noise comes from the muffler
Feedback Control http://focus.ti.com.cn/cn/lit/an/spra042/spra042.pdf
List of Design Options • Current Glass Pack* • Unpacked Concentric Tube Resonator • Multi-pass Resonator • Metal Foam* • Entire Length of Exhaust System Wrapped • Lava Rock/Rockwool and Stainless Steel Wool* • Multiple Exhaust Pipes (Combination) • End Cap Silencer (Combination) • ANC • Variable Length Resonator - Single Pass • Variable Length Resonator - Multiple Pass