Motor Vehicle Undertray Air Inlet for Engine Cooling
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Solution Overview
Problem
Existing undertray trim panels with NACA air inlets restrict packaging space in the engine compartment due to their required dimensions and oblique design, which can lead to premature air flow separation and inadequate cooling of components located further from the inlet.
Innovation Solution
The design incorporates an upper and lower flat element extending arcuately rearward and upward, with a planar air ram plate and eddy-producing structures such as air guiding plates or small NACA air inlets, which maintain a constant flow cross section and deflect warmer air, allowing for improved air flow separation and increased packaging space.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If a NACA air inlet is used to cool components behind the engine, then cooling efficiency is improved, but packaging space in the engine compartment is reduced
Solution Approach 1:
The patent transitions from a traditional three-dimensional NACA air inlet to a two-dimensional flat air inlet structure integrated into the undertray trim panel. This dimensional reduction allows the air inlet to provide effective cooling while occupying minimal space in the engine compartment, resolving the contradiction between cooling efficiency and packaging space.
Solution Approach 2:
The flat air inlet is divided into multiple segments including an upper flat element, a lower flat element, and a rear end portion with specific geometric configurations. This segmentation allows each element to be optimized for its specific function while collectively achieving effective cooling with reduced overall space requirements.
2Temperature
If a NACA air inlet with sufficient length and height is used to reach components further from the engine, then cooling coverage is improved, but the inlet must extend closer to the roadway violating minimum spacing requirements
Solution Approach 1:
The patent uses a flat two-dimensional air inlet structure that extends in the longitudinal direction while maintaining minimal vertical height. This allows the air inlet to reach components further from the engine horizontally without violating minimum spacing requirements from the roadway, achieving extended cooling coverage while complying with spacing regulations.
3Temperature
If the air inlet structure is extended to cool components further from the engine, then cooling effectiveness is improved, but air flow separation occurs prematurely
Solution Approach 1:
The patent incorporates specific curvature radii at critical transitions: the upper flat element has a curvature radius of 5-15% of its length at the transition to the rear end portion, and the lower flat element has a curvature radius of 10-20% of its length. These curved transitions prevent flow separation by smoothly guiding the air flow around corners, maintaining flow stability while extending cooling coverage to distant components.
Solution Approach 2:
The patent optimizes geometric parameters including the curvature radii, the angle alpha (5-15 degrees) of the upper flat element, and the angle beta (15-30 degrees) of the lower flat element. By carefully selecting these parameters, the air flow remains attached and stable throughout the extended inlet structure, preventing premature flow separation while achieving effective cooling of distant components.
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
This configuration enhances cooling efficiency by maintaining cooler air flow to components while reducing the vertical and horizontal space requirements in the engine compartment, allowing for a more compact engine arrangement and improved aerodynamics.
Implementation Method 1
the air inlet contains eddy producing structures, the eddy producing structures either being a plurality of air guiding plates which extend along a vehicle vertical axis and a vehicle longitudinal direction in the air inlet and which are curved transversely such that an overall flow cross section in the vehicle longitudinal direction is substantially constant
Implementation Method 2
the air inlet supplies air flow in the undertray trim panel... the supplied fresh air flows... the warmer air which circulates in the engine compartment and has flowed through the front radiator and the associated fan
Data Source
AI summary
A motor vehicle undertray trim panel having an air inlet delimited toward the vehicle and toward the roadway by upper and lower flat elements, respectively, which extend arcuately rearward and upward in the direction of a vehicle engine compartment for air flow cooling. The rear end of the upper flat element is adjoined by a planar air ram plate which runs by a small amount substantially vertically upward, and ends substantially freely in the engine compartment. The air inlet contains eddy producing structures. The structures may be a plurality of air guiding plates which extend along the vehicle vertical axis and the vehicle longitudinal direction in the air inlet and which are curved transversely such that the overall flow cross section in the vehicle longitudinal direction is substantially constant, or a plurality of small air inlets which are integrated into the air inlet.