Gearshift Point Determination via Engine Target Speed
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Solution Overview
Problem
Conventional methods for determining downshift and upshift points in a gearbox are time-consuming and costly, requiring extensive calibration and are not always effective across various driving situations, leading to unsatisfactory results.
Innovation Solution
A method and system that determine downshift and upshift points relative to an engine target speed, allowing for flexible and simplified adjustments without recalibrating every shift point, using a control unit connected to the gearbox and engine, where shift points are indirectly controlled via the engine target speed to maintain stability and adapt to changing conditions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If conventional tabulated shift points are used for gearbox control, then gear changes can be executed based on engine speed thresholds, but extensive calibration is required which is time-consuming and costly
Solution Approach 1:
The patent changes the fundamental parameter from fixed tabulated shift points to dynamically calculated shift points based on engine target speed. Instead of using pre-determined engine speed thresholds that require extensive field calibration, the system calculates shift points using a formula involving engine target speed, gear ratios, and transmission characteristics, thereby eliminating time-consuming calibration procedures while maintaining effective gear change execution
Solution Approach 2:
The patent creates a simplified mathematical model that copies the essential behavior of complex calibrated shift patterns. By using a formula-based approach that replicates the functional relationship between engine speed and gear selection, the system achieves the effectiveness of extensive calibration without actually performing the time-consuming field tests and data collection required by conventional methods
2Reliability
If extensive calibration is performed to optimize shift points for various driving situations, then gear change strategies can be optimized, but the results are not always satisfactory across all driving conditions
Solution Approach 1:
The patent transforms the static, pre-calibrated shift points into dynamic, continuously adaptable shift points. The system uses engine target speed as a variable parameter that automatically adjusts to different driving conditions, allowing the gear change strategy to adapt in real-time to varying loads, speeds, and operating conditions without requiring separate calibration for each situation
Solution Approach 2:
The patent creates a universal shift point calculation method that functions effectively across all driving situations. The formula-based approach using engine target speed, gear ratios, and transmission characteristics serves as a multi-functional solution that replaces multiple situation-specific calibration sets, providing reliable gear change optimization whether the vehicle is accelerating, cruising, or operating under load
3Adaptability or versatility
If individual shift points are adjusted for different driving conditions, then performance can be optimized, but recalibration of every shift point is required which increases complexity
Solution Approach 1:
The patent extracts the essential variables needed for shift point determination from complex calibration data. By identifying and using only the critical parameters (engine target speed, gear ratios, transmission characteristics), the system eliminates the need to calibrate and manage numerous individual shift points for different conditions, thereby reducing calibration complexity while maintaining adaptability
Solution Approach 2:
The patent performs preliminary establishment of the shift point calculation formula during system design, before actual operation. The mathematical relationship between engine target speed and shift points is pre-defined using basic transmission parameters, allowing the system to automatically adapt to different conditions without requiring preliminary field calibration or complex setup procedures
Data Source
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AI summary
The present invention relates to a method for determination of one or more downshift and upshift points for a gearbox in a motor vehicle, which vehicle comprises an engine connected to, in order to drive, said gearbox, where a downshift point represents a first engine speed at which said gearbox is adapted to effecting a downshift, and an upshift point represents a second engine speed at which said gearbox is adapted to effecting an upshift. Said method comprises one or more downshift and upshift points being determined relative to an engine target speed C?r which is a desired speed for said engine. The invention relates also to a system, a motor vehicle, a computer programme and a computer programme product thereof.