Construction Machine Noise Suppression via Partitioned Intake Duct
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Solution Overview
Problem
Construction machines with engine compartments face challenges in reducing noise emissions across a wide range of frequencies due to limitations in existing sound absorption techniques, particularly with high-frequency noise above 200 Hz and the need for large mufflers to suppress low-frequency noise, which are cumbersome and ineffective beyond narrow frequency ranges.
Innovation Solution
A construction machine design featuring a partitioned engine compartment with a duct system that encloses the air intake opening, creating a duct surrounding space to reflect sound and enhance noise suppression, combined with a perforated member and sound absorbers to manage noise across various frequencies in a compact configuration.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If interference type mufflers (Helmholtz resonator or side branch) are used to suppress low frequency noise, then low frequency noise (100 Hz to 200 Hz) is reduced, but the muffler becomes large and cannot be disposed in the engine compartment
Solution Approach 1:
The noise suppression chambers are nested within the existing engine compartment structure. The first and second intake chambers are integrated into the engine compartment's wall structure, with partition walls forming the chambers. This nesting approach allows the noise suppression functionality to be embedded within the existing compact space, avoiding the need for large external mufflers
Solution Approach 2:
Instead of using long side branches extending outward, the invention uses partition walls with openings to create acoustic pathways through the third dimension (through the wall thickness). The first intake chamber opening and second intake chamber opening provide acoustic communication paths that achieve noise suppression without requiring large external dimensions
2Object-affected harmful factors
If conventional sound absorbers or interference type mufflers are used, then noise suppression is achieved in a limited frequency range, but noise suppression beyond a narrow frequency range cannot be accomplished
Solution Approach 1:
The engine compartment is divided into multiple chambers (first intake chamber, second intake chamber, exhaust chamber) with partition members having specific openings. Each chamber is designed to target different frequency ranges, with the first intake chamber handling low frequency noise and the second intake chamber handling high frequency noise, thereby achieving broad-spectrum noise suppression across a wide frequency range
Solution Approach 2:
The partition members serve multiple functions: they structurally divide the engine compartment into separate chambers for organizational purposes, provide acoustic isolation between different noise sources, and create specific acoustic pathways through their openings to enable frequency-selective noise suppression. This multi-functionality allows a single structural element to address both spatial organization and broad-frequency noise control
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 design effectively reduces noise emissions across a wide frequency range, from 100 Hz to 500 Hz, in a compact form, without the need for large mufflers or active noise control systems, ensuring efficient airflow and noise suppression without the limitations of conventional methods.
Implementation Method 1
a duct (30) joined to the outer wall (15) so as to enclose the air intake opening (17), the duct (30) including an inner peripheral surface (31) enclosing a duct passage (32) leading to the air intake opening (17) and an outer peripheral surface (33). The duct (30) extends in a duct extension direction (30) different from the suction direction (X) and is disposed in the intake chamber (13) so as to define a duct surrounding space (40) around the outer peripheral surface (33) of the duct (30)
Data Source
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AI summary
The present invention provides a construction machine capable of preventing noise emission through an air intake opening of an engine compartment. The construction machine includes a partition member (25, 29) partitioning an accommodation space in an engine compartment (10) into a main chamber (11) and an intake chamber (13) while having an inter-chamber opening; a fan (21) disposed in the main chamber (11) to generate cooling air (C) flowing through an air intake opening (17), the intake chamber (13), the inter-chamber opening, and the main chamber (11) in this order by sucking air in the engine compartment (10) in a suction direction (X); a duct (30) joined to an outer wall (15) to enclose the air intake opening (17) and including an inner peripheral surface (31) enclosing a duct passage (32) leading to the air intake opening (17) and an outer peripheral surface (33). The duct (30) extends in a duct extension direction different from the suction direction (X) of the fan (21), disposed in the intake chamber (13) to define a duct surrounding space (40) around the outer peripheral surface (33) of the duct (30).