Vehicle Control Unit Uphill Start Logic with Dynamic Set Time
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Solution Overview
Problem
Existing vehicle control systems face challenges in accurately determining when to execute uphill start control, leading to erroneous determinations on flat roads and discomfort for occupants, due to variations in vehicle speed and gradient thresholds.
Innovation Solution
A vehicle control unit with multiple determination units and flags to assess vehicle speed and gradient conditions, using different threshold values and set times to differentiate between uphill and flat road scenarios, ensuring appropriate drive power distribution and reducing erroneous activations.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If the set time for determining uphill start control is shortened to allow rapid re-execution after cancellation, then the uphill starting performance is improved, but the system may erroneously execute uphill start control on flat roads causing occupant discomfort
Solution Approach 1:
The patent changes the parameter of set time dynamically based on the cancellation situation type. When the flag indicates the vehicle may have descended slightly, a shorter set time (e.g., 0.5 seconds) is used to enable rapid re-execution. When the flag indicates normal cancellation, a longer set time (e.g., 1.5 seconds) is used to prevent erroneous activation on flat roads. This parameter adaptation resolves the contradiction by adjusting the time threshold according to the specific operational context.
Solution Approach 2:
The system dynamically adjusts the determination criteria based on the cancellation situation type flag. Instead of using a fixed set time, the system switches between different time thresholds depending on whether the vehicle likely descended or stopped normally. This dynamic adaptation allows the system to optimize uphill starting performance when needed while maintaining reliability under normal conditions.
2Measurement precision
If the system determines uphill gradient continuously to improve control accuracy, then the uphill start control precision is improved, but the computational load and system complexity increase
Solution Approach 1:
The system performs preliminary determination of the cancellation situation type flag before re-evaluating uphill start control conditions. By pre-classifying the cancellation reason (normal stop vs. possible descent), the system prepares the appropriate set time threshold in advance, avoiding complex real-time calculations during the critical re-evaluation phase and reducing computational load.
Solution Approach 2:
The control logic is segmented into distinct determination units: a first cancellation determination unit that sets the flag, and a second cancellation determination unit that uses the flag to select appropriate set times. This segmentation divides the complex control system into manageable modules, each handling specific aspects of the decision-making process, thereby reducing overall system complexity while maintaining precision.
Data Source
AI summary
When a vehicle speed is equal to or higher than a first vehicle speed threshold value or an uphill gradient is lower than a first gradient threshold value and uphill start control is cancelled, if a state where the vehicle speed is lower than a second vehicle speed threshold value and the uphill gradient is equal to or higher than a second gradient threshold value continues for a first set time, uphill start control is executed. When the vehicle speed is decreased after being once increased within a range where the vehicle speed is lower than the first vehicle speed threshold value and uphill start control is cancelled, if a state where the vehicle speed is lower than the second vehicle speed threshold value and the uphill gradient is equal to or higher than the second gradient threshold value continues for a second set time, the uphill start control is executed.