Intake Temperature Sensor Heat Sink Design
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Solution Overview
Problem
Conventional intake temperature sensors face accuracy and responsiveness issues at low air mass flow due to increased thermal resistance, leading to detection delays and errors, as they are not effectively designed to reduce thermal influence from attachment parts and self-heating.
Innovation Solution
A temperature detecting element is fixed to a heat sink directly exposed to the intake flow, reducing thermal resistance and improving accuracy and responsiveness by enhancing heat dissipation and mechanical protection.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If the intake-temperature detecting element is directly exposed to intake flow using a metal terminal, then the structural simplicity is maintained, but the thermal resistance from the surface of the detecting element to the intake flow rapidly increases at low air mass flow, causing detection accuracy degradation and detection delay
Solution Approach 1:
The patent transitions from a one-dimensional direct exposure configuration to a three-dimensional heat sink structure with extended surfaces. The heat sink includes a detection element mounting portion and plate portions extending in multiple directions, increasing the surface area for thermal exchange with the intake flow without complicating the overall device structure.
Solution Approach 2:
The patent introduces a heat sink as an intermediary component between the detection element and the intake flow. The heat sink acts as a thermal mediator that enhances heat transfer efficiency, particularly at low air mass flow conditions, by providing extended surface areas that facilitate better thermal coupling with the passing air.
2Speed
If the intake-temperature detecting element is directly exposed to intake flow, then the detection responsiveness is improved, but the thermal time constant reaches several tens of seconds at low air mass flow, increasing detection delay
Solution Approach 1:
The heat sink structure extends in multiple spatial dimensions with plate portions that increase the effective surface area for thermal exchange. This dimensional expansion allows for enhanced heat transfer capability that reduces the thermal time constant and detection delay without sacrificing structural simplicity.
3Device complexity
If the intake-temperature detecting element is disposed in a sub-passage, then the structural integration is improved, but the thermal influence from the sub-passage structure and circuit board causes temperature errors, particularly at low air mass flow
Solution Approach 1:
The patent extracts the detection element from the thermally influenced sub-passage environment and mounts it on a heat sink that is directly exposed to the intake flow. This extraction removes the detection element from the harmful thermal environment of the circuit board and housing, eliminating the source of temperature measurement errors.
Solution Approach 2:
The heat sink serves as a thermal intermediary that isolates the detection element from harmful thermal influences while maintaining direct exposure to the intake flow. The heat sink's extended surfaces provide a dedicated thermal pathway that is independent of the circuit board and housing thermal fields.
4Object-affected harmful factors
If the circuit board employs materials with high thermal resistance, then the self-heating influence is reduced, but the thermal resistance to the airflow is insufficient, causing the thermal time constant to reach several tens of seconds
Solution Approach 1:
The heat sink structure compensates for the high thermal resistance of the circuit board material by providing extensive surface area in multiple dimensions. The plate portions extend in directions that maximize exposure to the intake flow, creating sufficient thermal coupling despite the insulating circuit board substrate.
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 enables high-speed and accurate intake temperature detection even at low air mass flow, reducing thermal time constants and detection delays, thereby improving controllability in engine control systems.
Implementation Method 1
a heat sink 4 directly exposed to the intake flow in the intake pipe 3... reducing thermal resistance and improving accuracy and responsiveness by enhancing heat dissipation
Implementation Method 2
fixing a temperature detecting element to a heat sink directly exposed to the intake flow... enhancing heat dissipation
Data Source
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AI summary
An intake temperature sensor 9 capable of precisely detecting the temperature of intake at high speed even in a low air mass flow zone is provided. In an intake temperature sensor 9 having a temperature detecting element 6 inserted in an opening provided in an intake pipe 3 to be disposed in the intake pipe, a temperature detecting element is mechanically joined with a heat sink 4 directly exposed to the flow of the intake flowing in the intake pipe, and the temperature of the intake is output based on an output obtained from the temperature detecting element. Thus, the thermal resistance of the temperature detecting element with respect to the intake flow can be reduced; therefore, the intake temperature sensor 9 capable of precisely detecting the temperature of the intake at high speed even in the low air mass flow zone can be provided.