Tandem Axle Lubrication Control for 6×2 and 6×4 Operation
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Solution Overview
Problem
Tandem axle systems face inefficiencies and component wear issues due to inadequate lubrication levels when transitioning between 6×2 and 6×4 axle configurations, with existing systems either reducing efficiency or durability.
Innovation Solution
An adjustable lubrication system that adjusts oil levels in the axle sump based on the axle configuration using an external reservoir, electric pump, and gravity feed, ensuring optimal lubrication levels for both configurations without parasitic power loss.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Force
If a tandem axle system operates with a 6×4 axle configuration (both axles powered), then tractive power is increased, but fuel efficiency is reduced
Solution Approach 1:
The system dynamically transitions between 6×4 and 6×2 axle configurations based on operating conditions, allowing the vehicle to optimize between tractive power and fuel efficiency. The second axle can be connected or disconnected from the drive shaft, enabling the system to adapt its powertrain characteristics to match road conditions, load requirements, and speed ranges.
2Reliability
If the oil level in the axle sump is increased for 6×4 operation, then component wear is reduced, but vehicle efficiency is reduced during 6×2 operation
Solution Approach 1:
The lubrication system dynamically adjusts oil levels in the axle sump based on the current axle configuration. During 6×4 operation, the system maintains higher oil levels to ensure adequate lubrication for both axles. During 6×2 operation, the system reduces oil levels to minimize parasitic drag and improve fuel efficiency, while still maintaining sufficient lubrication for the engaged axle.
Solution Approach 2:
The system changes the oil level parameter in the axle sump according to the operating mode. This parameter adjustment allows the system to optimize the balance between lubrication adequacy and efficiency, with higher oil levels providing better lubrication but increased drag, and lower oil levels reducing drag but potentially compromising lubrication.
3Quantity of substance
If a pump is used to transfer engine oil to an external reservoir during 6×4 operation, then oil level adjustment is achieved, but parasitic power loss occurs and pump failure risks low oil levels
Solution Approach 1:
The system uses gravity feed from the engine oil system to automatically maintain oil levels in the axle sump during 6×4 operation, eliminating the need for an additional pump. The engine's own oil circulation system serves the dual purpose of lubricating the engine and replenishing the axle sump, reducing component count and potential failure points.
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 enhances vehicle efficiency in the 6×2 configuration and reduces component wear in the 6×4 configuration, providing the benefits of both configurations while maintaining customer satisfaction.
Implementation Method 1
the first oil passage including an electric pump
Implementation Method 2
the second oil passage including a valve
Data Source
AI summary
Methods and systems are provided for adjusting a lubrication system based on an axle configuration of a tandem axle with a disconnect feature. In one example, a method may include adjusting an oil level in an axle sump of a tandem axle based on an axle configuration of the tandem axle (e.g., whether the tandem axle is operating with one of a 6×4 axle configuration and a 6×2 axle configuration), the axle sump selectably coupled to an external reservoir via a first passage and a second passage, the first passage including an electric pump, the second passage including a valve, and the tandem axle coupled to a drivetrain of a motor vehicle. In this way, an amount of oil in the axle sump may be adjusted based on the tandem axle configuration.