Gearshift Point Determination Using Engine Speed Difference
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Solution Overview
Problem
Conventional gearbox shift point determination methods fail to adapt dynamically to varying driving conditions, such as road gradient and vehicle weight, leading to suboptimal drivability, acceleration, comfort, and fuel efficiency.
Innovation Solution
A method for determining shift points based on an engine target speed and a first engine speed difference, which considers the engine's desired speed and torque delivery capacity, allowing for adaptive shift point adjustment in real-time according to changing conditions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If tabulated engine speed limits are used for gearshift determination, then the control system is simple to implement, but the system cannot adapt dynamically to varying driving conditions such as road gradient and vehicle weight
Solution Approach 1:
The patent applies dynamics by transitioning from static tabulated shift points to dynamic shift point determination based on real-time engine target speed and engine speed difference. The system continuously calculates optimal shift points adapting to changing driving conditions including road gradient and vehicle weight, making the gearshift control adaptive rather than fixed.
Solution Approach 2:
The patent changes the parameters used for shift point determination from fixed engine speed thresholds to dynamic parameters including engine target speed and engine speed difference. By monitoring changes in these parameters over time, the system determines optimal shift points that adapt to current driving conditions while maintaining manageable computational complexity.
2Ease of operation
If conventional tabulated shift points are used, then the system is easy to operate, but drivability and fuel efficiency are suboptimal
Solution Approach 1:
The patent implements feedback by continuously monitoring engine speed, comparing it to target speed, and using the engine speed difference to determine optimal shift points. This closed-loop approach ensures the engine operates in optimal efficiency ranges while maintaining simple automatic operation without driver intervention.
Solution Approach 2:
The system performs self-service by automatically determining and executing gearshifts based on real-time engine performance data. The control unit independently calculates optimal shift points using engine target speed and engine speed difference, eliminating the need for manual driver judgment while optimizing fuel efficiency and drivability.
3Reliability
If shift points are optimized for specific engine types, then performance is maximized, but the system requires specific adjustments for each engine type
Solution Approach 1:
The patent achieves universality by creating a shift point determination method that works across different engine types without specific calibration. The approach using engine target speed and engine speed difference is universally applicable to various engines, providing reliable performance optimization while maintaining adaptability to different engine characteristics through the generalizable calculation methodology.
Data Source
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AI summary
The present invention relates to a method for determination of one or more shift points for a gearbox in a motor vehicle which comprises an engine connected to, in order to drive, said gearbox, where a shift point represents an engine speed at which said gearbox is adapted to effecting a downshift or upshift, said one or more shift points are determined on the basis of an engine target speed ? T and a first engine speed difference ?? TT , said target speed ? T is a desired speed for said engine, said first engine speed difference ?? TT is a difference between a first engine speed at a first time t 1 and said target speed ? T at a second time t 2, and said first and second times t 1 and t 2 are separated by a time period T. The invention relates also to a system, a motor vehicle, a computer programme and a computer programme product thereof.