Power Transmission Oil Temperature Sensor Positioning
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Solution Overview
Problem
In hybrid vehicles, the oil temperature sensor is exposed to air when the mechanical and electric oil pumps are stopped, leading to incorrect temperature detection and delayed restart temperature detection, and using separate sensors increases costs, while submerging a single sensor in the oil pan results in varying oil temperatures.
Innovation Solution
A power transmission device configuration where the discharge passages of the mechanical and electric oil pumps are merged before connecting to an oil supply, with check valves and an oil temperature sensor positioned vertically lower than the oil-introducing portion, ensuring the sensor remains submerged and detects oil temperatures correctly.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If the oil temperature sensor is positioned at the same height as the oil-introducing portion, then the sensor can detect oil temperature during operation, but the sensor is exposed to air when pumps are stopped, leading to incorrect temperature detection
Solution Approach 1:
The oil temperature sensor is repositioned from a horizontal alignment with the oil-introducing portion to a vertical position below it. This dimensional change ensures that the sensor remains submerged in oil at the lowest point of the merging section, preventing air exposure and ensuring continuous accurate temperature detection regardless of pump operation status.
2Measurement precision
If separate oil temperature sensors are provided for mechanical and electric oil pumps, then temperature detection accuracy is improved, but equipment cost increases
Solution Approach 1:
Instead of providing separate temperature sensors for each pump, the patent merges the detection function into a single sensor positioned at the lowest point of the merged discharge passages. This single sensor detects the temperature of oil from both pumps, eliminating redundant components and reducing cost while maintaining detection accuracy.
Solution Approach 2:
The single oil temperature sensor positioned at the lowest point of the merging section serves a universal function by detecting the temperature of oil from both the mechanical and electric oil pumps simultaneously. This multi-functional positioning eliminates the need for separate sensors while ensuring accurate temperature monitoring of the combined oil flow.
3Device complexity
If a single oil temperature sensor is submerged in the oil pan, then equipment cost is reduced, but the temperature varies by location leading to incorrect detection
Solution Approach 1:
Instead of submerging the sensor anywhere in the oil pan, the patent positions the sensor at a specific local position - the lowest point of the merging section where discharge passages from both pumps converge. This precise local positioning ensures the sensor detects the actual temperature of the pumped oil rather than the variable temperature of the oil pan, maintaining high measurement precision with a single sensor.
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
Enables accurate detection of oil temperatures at the discharge ends of both pumps using a single sensor when stopped, reducing the time lag in temperature detection compared to existing systems and avoiding increased costs.
Implementation Method 1
a first check valve (18) and a second check valve (19) are respectively provided on the first discharge passage (15) and on the second discharge passage (16)
Implementation Method 2
an oil temperature sensor (20) is provided at a part of the merging section (17) which is disposed at a position that is vertically lower than an oil-introducing portion (22)
Implementation Method 3
the merging section (17) is disposed at a position that is vertically lower than an oil-introducing portion (22) of the oil cooler (14)
Data Source
AI summary
A power transmission device has a first check valve and a second check valve on the respective discharge passages. An oil temperature sensor is disposed at a position that is vertically lower than an oil-introducing portion of a merging section.