Homogenizing Grid for Vehicle Heating Airflow
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Solution Overview
Problem
Existing heating devices in motor vehicles, particularly those with high voltage PTC heating elements, face challenges in maintaining uniform air flow distribution and temperature control, leading to thermal imbalances and comfort issues due to the need for cooling of electronic control units and heat sinks.
Innovation Solution
A homogenizing grid is introduced upstream of the electric heating device, featuring a combination of larger first openings for cooling heat sinks and smaller second openings for uniform air distribution, along with a solid part to manage airflow and maintain a temperature difference within ±5°C across air outlets.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If heat sinks are arranged on one side of the heating device to cool the electronic control unit, then the electronic control unit is cooled effectively, but thermal imbalance occurs between air outlets on opposite sides of the heating device
Solution Approach 1:
The homogenization grid implements local quality by creating different opening configurations in different zones: a first zone with larger openings facing the heat sink side to provide additional cooling, and a second zone with smaller openings facing the opposite side to maintain thermal balance. This localized differentiation allows the system to cool the electronic control unit effectively while preventing thermal imbalance at the air outlets.
2Reliability
If more air is directed to heat sinks for cooling, then thermal protection cutoff is avoided, but temperature difference between air outlets exceeds the desired tolerance
Solution Approach 1:
The homogenization grid applies parameter changes by varying the opening sizes in different zones to control air flow distribution. The first zone has larger openings to increase air flow to the heat sink side for cooling, while the second zone has smaller openings to restrict air flow to the opposite side. This parameter differentiation maintains temperature uniformity within the desired ±5°C tolerance while providing sufficient cooling to prevent thermal protection cutoff.
3Temperature
If a homogenization grid with uniform openings is used, then air flow is distributed evenly, but insufficient cooling is provided to the heat sinks on one side
Solution Approach 1:
The homogenization grid implements local quality by creating different opening configurations in different zones: a first zone with larger openings facing the heat sink side to provide additional cooling, and a second zone with smaller openings facing the opposite side to maintain thermal balance. This localized differentiation allows the system to cool the electronic control unit effectively while preventing thermal imbalance at the air outlets.
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 ensures effective cooling of electronic control units and uniform air flow distribution, preventing thermal protection cutoffs and meeting comfort temperature requirements by maintaining a consistent temperature difference across the heating device's air outlets.
Implementation Method 1
a motor-driven fan unit also called a blower to cause the air flow to circulate from the air inlet to the air distribution outlet
Implementation Method 2
heat sinks can be provided in thermal contact with the connector carrying the electronic control unit
Implementation Method 3
the heating device comprises resistive elements, for example with a positive temperature coefficient (PTC), such as PTC stones
Data Source
Figure 1~2
Figure 3~4
AI summary
The invention concerns a grid (14) for homogenising an air stream for a heating apparatus for a motor vehicle comprising an electric heating device, said grid comprising: - a first area (Z1) having at least one first opening (29) intended to be arranged upstream from at least one heat sink in the direction of flow of said air stream, said at least one heat sink being arranged on one side of said heating device, and - a second area (Z2) separate from the first area (Z1) and having a plurality of second openings (31) intended to be arranged upstream from at least one heating element of said heating device in the direction of flow of said air stream. The invention also concerns a heating apparatus comprising: - an electrical heating device comprising: at least one heating element, an electronic control unit, and at least one heat sink arranged on one side of said heating device, and - such a grid (14) arranged upstream from said heating device in the direction of flow of said air stream.