Intake Noise Attenuation Device for Engine Airflow
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Solution Overview
Problem
Existing intake manifold noise reduction systems using air diffusers with radial vanes can decrease bulk airflow, leading to reduced engine power output and noise generation due to turbulent airflow around discontinuities, which complicates packaging and airflow control.
Innovation Solution
A noise attenuation device with a plurality of vanes is positioned directly downstream of the throttle body in the intake passage, where the vanes extend inwardly for a predetermined height equal to the difference between the radius of the throttle body and the intake passage, diffusing and redirecting airflow to reduce noise without obstructing bulk airflow.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If radial vanes protrude into the intake path to reduce noise, then noise attenuation is improved, but bulk airflow is decreased
Solution Approach 1:
The noise attenuation device applies local treatment only at the discontinuity location where radius changes occur, rather than using radial vanes throughout the entire intake path. This localized approach targets the specific noise source without obstructing the main airflow path, resolving the contradiction between noise attenuation and bulk airflow maintenance
Solution Approach 2:
A noise attenuation device with vanes is introduced as an intermediary component positioned at the discontinuity. The device height is specifically designed to be substantially equal to the radius difference, allowing it to mitigate noise at the transition zone while leaving the main intake passage open for uninterrupted bulk airflow
2Productivity
If throttle bore is increased to counteract flow restrictions, then bulk airflow is improved, but packaging space and airflow controllability are worsened
Solution Approach 1:
Instead of increasing the throttle bore size (excessive action), the invention uses a partial action approach by adding a noise attenuation device with height equal to the radius difference. This partial modification addresses the noise issue without requiring larger components, thereby maintaining compact packaging while preserving bulk airflow
3Object-affected harmful factors
If radial vanes are used to disrupt air flow pattern, then noise is reduced, but engine power output is decreased
Solution Approach 1:
The invention applies noise attenuation locally at the discontinuity where radius changes cause turbulence, rather than using radial vanes that extend into the main airflow path. This localized disruption of airflow pattern reduces noise without significantly impacting the bulk airflow that determines engine power output
Solution Approach 2:
The harmful noise-generating turbulence is extracted and addressed specifically at the discontinuity location, separating the noise attenuation function from the main airflow path. This allows noise reduction without the penalty of reduced engine power output that occurs when radial vanes obstruct the primary airflow
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
The solution effectively decreases noise emanating from the intake passage while maintaining engine power output by diffusing and redirecting airflow, thereby addressing the issues of noise reduction and airflow control.
Implementation Method 1
The vanes may diffuse and/or redirect air flow that may otherwise impinge onto surfaces of the intake passage and produce an undesired noise
Data Source
AI summary
Methods and systems are provided for a noise attenuation device. In one example, a system may include a noise attenuation device located downstream of a throttle body with a height less than or equal to a difference in radiuses between a bore of the throttle body and an intake passage.