Gear Device Oil Temperature Control via Heat Exchanger
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Solution Overview
Problem
Conventional gear devices experience drive loss and reduced fuel efficiency due to high viscous resistance from lubricating oil at low temperatures, particularly during cold starts, as they lack an efficient mechanism to quickly raise the oil temperature and reduce oil amount.
Innovation Solution
A gear device with a circulation pump that controls the temperature of lubricating oil by exchanging heat with engine cooling water in a heat exchanger, positioned outside the enclosure, and adjusts the oil level by varying the pumping amount, using sensors to optimize oil quantity and temperature based on vehicle speed and oil temperature.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If the gear device uses conventional natural warm-up methods (friction between gears, churning energy of lubricating oil, heat transmission from engine), then the structure remains simple with no exclusive warm-up device, but the temperature of lubricating oil rises slowly especially at cold start, causing high viscous resistance and increased drive loss
Solution Approach 1:
The patent merges the gear device with the engine cooling water system by introducing a heat exchanger that utilizes the engine cooling water to heat the lubricating oil. This combination allows the gear device to benefit from the engine's thermal energy without requiring a separate, complex warm-up system, thus resolving the contradiction between structural simplicity and effective temperature control.
Solution Approach 2:
The heat exchanger acts as an intermediary between the engine cooling water and the lubricating oil, enabling heat transfer from the cooling water to the oil. This mediator component facilitates efficient warm-up of the lubricating oil while maintaining the simplicity of the overall system architecture.
2Reliability
If the gear device fills a specified amount of oil inside the housing for lubrication and cooling, then adequate lubrication is provided, but the drive loss from churning resistance increases, deteriorating fuel efficiency
Solution Approach 1:
The patent introduces an oil level control mechanism that dynamically adjusts the amount of lubricating oil in the housing based on operating conditions. By making the oil quantity adjustable rather than fixed, the system can optimize the balance between adequate lubrication and minimized churning resistance, thereby reducing drive loss while maintaining reliable lubrication when needed.
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 quickly raises the lubricating oil temperature, reduces viscous resistance, and minimizes oil quantity, resulting in lower drive loss and improved fuel efficiency with fewer components, effectively addressing the issue of cold-start fuel inefficiency.
Implementation Method 1
causing the lubricating oil and cooling water for an internal combustion engine to exchange heat with each other in the heat exchanger
Data Source
Figure 1~2
Figure 3~4
AI summary
Provided are a gear device in which lubricating oil for cooling and lubricating gears to be driven therein is adjusted to a temperature and an amount suitable for the speed of a vehicle, and a vehicle having the gear device mounted thereon. In a transmission 1 which adjusts the temperature of lubricating oil OL by supplying the lubricating oil OL from a lower part of a housing (enclosure) 11 of the transmission 1 into a heat exchanger 12 by means of a circulation pump 13 and causing the lubricating oil OL and engine cooling water W to exchange heat with each other in the heat exchanger 12, the level of the lubricating oil OL retained in an oil pan 11a when the circulation pump 13 is stopped is defined as a highest oil level L1, while the level of the lubricating oil OL retained in the oil pan 11a when the amount of the lubricating oil OL pumped up by the circulation pump 13 is maximum is defined as a lowest oil level L2. The heat exchanger 12 is disposed at a position outside the housing 12 and higher than the highest oil level L1. The transmission 1 comprises a control device 20 which controls the amount of the oil to be pumped up by the lubricating pump 13 to adjust the height of the level OL of the oil which varies between the highest oil level L1 and the lowest oil level L2.