Flow sensor for vehicle liquid heater which protects against overheating
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Solution Overview
Problem
Existing flow heaters for electric vehicles are prone to failure due to unpredictable coolant flow conditions, leading to potential overheating and fire risks, as they lack accurate flow detection mechanisms to prevent dry burning and damage to the heating resistor and insulating layers.
Innovation Solution
A flow heater with a swing mechanism that detects liquid flow using a magnet and hall sensor, triggering a failure protection procedure to switch off heating power when no flow is detected, and incorporating a bypass liquid path to maintain coolant flow and prevent overheating.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If no flow detection mechanism is installed, then the heater structure remains simple, but the heater is prone to overheating and dry burning causing failure
Solution Approach 1:
The patent uses magnetic field detection (analogous to color change detection) where the hall sensor detects the magnetic field changes caused by the swing mechanism's position to determine coolant flow status, enabling reliable flow detection without complex mechanical structures
Solution Approach 2:
The patent replaces complex mechanical flow detection mechanisms with a magnetic field-based detection system using a hall sensor and swing mechanism, reducing mechanical complexity while improving reliability through non-contact sensing
2Measurement precision
If a swing mechanism with hall sensor is added for flow detection, then flow detection accuracy improves, but the device complexity increases
Solution Approach 1:
The patent introduces a magnetic field as an intermediary between the swing mechanism and the hall sensor, allowing non-contact detection of coolant flow status. The swing mechanism's movement changes the magnetic field position, which the hall sensor detects to determine flow conditions with high precision
Solution Approach 2:
The swing mechanism serves multiple functions: it acts as both a flow detection indicator and a bypass valve controller. When coolant flows, the swing mechanism moves to close the bypass; when flow stops, it returns to open the bypass, providing both detection and protection functions
3Productivity
If heating power is continuously applied, then heating efficiency is high, but the risk of dry burning and overheating increases
Solution Approach 1:
The patent implements a feedback control system where the hall sensor continuously monitors coolant flow status and provides real-time feedback to the control unit. Based on this feedback, the control unit adjusts or cuts off heating power to prevent overheating and dry burning, ensuring safe operation
Solution Approach 2:
The patent uses the swing mechanism to preliminarily close the bypass channel when coolant flow is detected, ensuring that heating power is applied only when coolant is flowing through the heater channels, preventing dry burning before it can occur
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 provides real-time flow data for accurate control, preventing overheating and reducing the risk of heater failure, while minimizing the risk of leakage and energy consumption.
Implementation Method 1
If there is liquid flow, liquid pushed against the swing mechanism and causes it to move or pivot away from its resting position
Implementation Method 2
Outside of the passageway a hall sensor may be arranged to detect the position of the flap or valve block. A magnet, e.g., magnetic steel, is fixed on the flap or valve plate
Implementation Method 3
a heating source located on the outside of intermediate section of the passageway
Data Source
AI summary
A flow heater for new forms of vehicles. The flow heater comprises a passageway for liquid, a heating source, a swing mechanism arranged in the passageway, and a sensor for detecting a position of the swing mechanism. In some embodiments, the swing mechanism includes a flap and a stopper wherein the flap is hinged to an inner wall and the stopper is fixed to an inner wall and located to abut the flap in the absence of flow.