Vehicle Shift Point Control Using Sensorless Slope Estimation
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Solution Overview
Problem
Existing multi-gear transmission systems in vehicles, particularly electric heavy-duty trucks, lack accurate slope and weight sensing, leading to suboptimal shift points and potential shifting failures on slopes with varying loads.
Innovation Solution
A method and apparatus for determining a target shift point in vehicles by calculating a slope indication value based on slope drag, vehicle weight, and reference mass, without requiring slope and gravity sensors, and adjusting the shift line accordingly.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If slope and gravity sensors are installed to accurately perceive road conditions, then measurement precision of slope and weight is improved, but device complexity and data acquisition costs increase
Solution Approach 1:
The patent replaces physical slope and gravity sensors with a computational model that calculates slope indication values using force analysis. The controller computes slope drag force based on vehicle parameters (mass, rolling resistance coefficient, air resistance coefficient) and motion state (acceleration, speed), then derives the slope indication value from these calculations, eliminating the need for additional sensing hardware.
Solution Approach 2:
The vehicle's existing sensor system (accelerometers, speed sensors, engine parameters) serves dual purposes: monitoring vehicle operation and providing data for slope calculation. The controller utilizes already-acquired vehicle state data to compute slope indication values, making the existing sensor infrastructure work for both its original function and slope detection.
2Productivity
If shift points are optimized based on accurate slope and weight data, then shift quality and energy efficiency are improved, but device complexity increases due to additional sensors
Solution Approach 1:
The patent replaces physical slope and gravity sensors with a computational model that calculates slope indication values using force analysis. The controller computes slope drag force based on vehicle parameters (mass, rolling resistance coefficient, air resistance coefficient) and motion state (acceleration, speed), then derives the slope indication value from these calculations, eliminating the need for additional sensing hardware.
Solution Approach 2:
The patent changes the approach from direct physical measurement to computational parameter derivation. Instead of measuring slope directly with sensors, the system calculates it by changing the parameter representation from physical quantity measurement to mathematical model computation, using force balance equations to derive slope indication values from readily available vehicle operational parameters.
3Device complexity
If conventional shift lines are used without slope compensation, then device complexity is reduced, but shift quality deteriorates on slopes leading to shifting failures
Solution Approach 1:
The patent implements dynamic adjustment of shift lines based on real-time slope indication values. The controller continuously updates the shift line parameters according to the calculated slope conditions, making the transmission control adaptive to changing road gradients. This dynamic approach maintains shifting reliability across varying slope conditions without requiring complex mechanical modifications.
Solution Approach 2:
The patent changes the approach from direct physical measurement to computational parameter derivation. Instead of measuring slope directly with sensors, the system calculates it by changing the parameter representation from physical quantity measurement to mathematical model computation, using force balance equations to derive slope indication values from readily available vehicle operational parameters.
Data Source
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AI summary
Embodiments of the present disclosure relate to a method, an apparatus, a device, a vehicle, and medium for determining a shift point of a vehicle. The method includes determining the slope drag of the vehicle based on the drive force, rolling resistance, air resistance, and acceleration resistance of the vehicle. The method further includes determining the slope indication value for the vehicle based on the slope drag and reference mass of the vehicle, wherein the slope indication value is associated with the slope of the vehicle. Further, the method further includes determining a target shift point of the vehicle in slope condition based on the slope indication value, and the gear and throttle opening of the vehicle. Through the method according to the examples of the present disclosure, in the absence of a slope sensor and a gravity sensor, the appropriate shift point of the vehicle can also be determined based on the slope indication value to optimize the shift point and the shifting force, improve the shift quality, and avoid shifting failures and other serious driving faults.