Differential Oil Cooling With Tank Recirculation and Thermal Valve
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Solution Overview
Problem
Engine power output requirements and towing loads often cause differential oil temperatures to exceed threshold limits, and while some oil formulations offer fuel economy improvements, they have lower temperature threshold limits, necessitating effective cooling solutions without the added cost of conventional coolant systems.
Innovation Solution
A differential cooling system comprising a housing with a tank containing oil, where a valve allows cooler oil from the tank to be recirculated when the housing oil temperature exceeds a predetermined level, using either a wax valve or a controller and temperature sensor for temperature regulation, ensuring efficient oil temperature management.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If conventional coolant systems are used to cool differential oil, then temperature control is effective, but system cost and complexity increase
Solution Approach 1:
The patent extracts the cooling function from a complex conventional coolant system and implements it through a simple auxiliary tank connected to the differential housing. The tank stores cool oil and provides it to the differential when needed, eliminating the need for complex coolant pumps, radiators, and control systems while maintaining effective temperature control.
Solution Approach 2:
The system uses the differential's own rotation to drive the oil circulation. The rotating differential housing splashes oil from the auxiliary tank back into the differential without requiring external pumps or motors, making the system self-powered and significantly reducing complexity.
2Use of energy by moving object
If fuel-efficient oil formulations are used, then fuel economy improves, but temperature threshold limits are reduced
Solution Approach 1:
The auxiliary tank pre-cools the oil before it enters the differential by storing oil in a separate chamber that is cooler than the operating differential. This preliminary cooling action allows fuel-efficient oil with lower temperature thresholds to operate safely by ensuring the oil starts at a lower temperature before undergoing shear heating in the differential.
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 system effectively cools the differential oil, preventing overheating and extending the temperature threshold of the oil, thereby enhancing fuel efficiency and reducing the need for costly conventional coolant systems.
Implementation Method 1
The valve may be a wax valve. The wax valve may be adapted to close when the oil temperature in the housing is below the predetermined level.
Implementation Method 2
a temperature sensor that senses the oil temperature of the oil in the housing and provides a signal to the controller when the oil temperature of the oil in the housing is above a predetermined level
Implementation Method 3
The housing contains oil that is splashed by a gear within the housing.
Implementation Method 4
A tank inlet receives oil from the housing and directs the oil to the tank until the tank is full. A tank outlet provides oil to the housing from the tank. The tank outlet includes a valve that opens when the oil temperature in the housing is above a predetermined level to allow the oil in the tank to be supplied to the housing and recirculated
Data Source
AI summary
A cooling system differential oil contained in the housing of a differential for a vehicle. The differential includes a housing containing a first portion of differential oil. A tank contains a second portion of differential oil. An inlet passage is provided through which differential oil flows from the housing to the tank. An outlet passage is provided through which differential oil flows from the tank to the housing. A valve is disposed in the outlet passage that has a closed position preventing differential oil from flowing through the outlet passage. The valve has an open position in which differential oil is permitted to flow from the tank to the housing in response to the temperature of the differential oil in the housing exceeding a predetermined temperature.