Auxiliary Braking Axle Shift-Assist Drivetrain Control
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Solution Overview
Problem
Engine downspeeding negatively affects the performance of auxiliary braking apparatuses in commercial vehicles, as their efficacy is positively related to engine speed, leading to overheating and reduced effectiveness of foundation braking systems.
Innovation Solution
A vehicle driveline system with a control system that selectively engages a second axle assembly with a different drive ratio when an auxiliary braking system is detected, allowing for engine speed management to enhance braking performance during auxiliary braking operations.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Use of energy by moving object
If engine downspeeding is used to improve fuel efficiency, then fuel efficiency is improved, but auxiliary braking performance deteriorates because efficacy is positively related to engine speed
Solution Approach 1:
The system dynamically adjusts the drivetrain configuration by selectively engaging the second axle assembly based on operating conditions. When auxiliary braking is detected, the control system engages the second axle to provide a different drive ratio that maintains engine speed within the optimal range for auxiliary braking apparatus efficacy, thus resolving the contradiction between fuel efficiency and braking performance
Solution Approach 2:
The system changes the drive ratio parameter by engaging the second axle assembly with a different drive ratio than the first axle assembly. This parameter change allows the engine to operate at higher speeds during auxiliary braking operations while still achieving fuel efficiency during normal operation, thereby maintaining both fuel efficiency and auxiliary braking performance
2Power
If engine downspeeding is used to maintain horsepower, then horsepower is maintained, but foundation braking systems overheat and effectiveness is reduced
Solution Approach 1:
The control system dynamically engages the second axle assembly when auxiliary braking is detected, creating a drivetrain configuration that allows engine speed to remain higher during braking operations. This dynamic adjustment prevents excessive heat generation in foundation braking systems while maintaining required horsepower levels
3Reliability
If auxiliary braking apparatus are used to reduce stopping distances, then stopping distances are reduced, but engine speed must be increased which reduces fuel efficiency
Solution Approach 1:
The drivetrain is segmented into two separate axle assemblies with different drive ratios. The first axle assembly is used for normal operation to maximize fuel efficiency, while the second axle assembly is selectively engaged during auxiliary braking operations to optimize stopping distance performance. This segmentation allows both contradictory requirements to be satisfied in their respective operating conditions
Data Source
AI summary
A vehicle driveline including a first axle assembly having a first drive ratio. A second axle assembly in selective driving engagement with the first axle assembly, the first and second axle assemblies having a second drive ratio when in driving engagement. A control system in electrical communication with the first and second axle assemblies, wherein the control system selectively engages the second axle assembly with the first axle assembly.