Hybrid Vehicle Control System Engine Start Threshold
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Solution Overview
Problem
Hybrid vehicle control systems face challenges in maintaining robustness and comfort during unintended operating mode changes, particularly in purely electric driving and internal combustion engine starting.
Innovation Solution
The control system uses an electronic control unit that detects vehicle speed and desired driving performance to start the internal combustion engine only when necessary, ensuring prolonged purely electric driving in urban areas while ensuring starting robustness and comfort, and uses dynamic performance prediction to anticipate and prepare for higher speeds outside urban areas.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the internal combustion engine is started frequently to ensure adequate driving performance, then the starting robustness is improved, but the duration of purely electric driving is reduced
Solution Approach 1:
The control system performs preliminary evaluation of the desired driving performance against threshold values before deciding to start the internal combustion engine. By predicting whether the electric motor will suffice based on current driving demands and battery state of charge, the system avoids unnecessary engine starts while ensuring robustness when needed.
Solution Approach 2:
The system dynamically adjusts the threshold for starting the internal combustion engine based on the state of charge of the battery. When the state of charge is high, the threshold is set higher to maintain purely electric driving longer. When the state of charge is low, the threshold is adjusted to ensure adequate starting robustness. This parameter adaptation resolves the contradiction by making the start decision context-dependent.
2Ease of operation
If the internal combustion engine is started early to ensure adequate driving performance, then the starting comfort is improved, but the loss of energy increases
Solution Approach 1:
The control system performs preliminary assessment of the driving situation by comparing the desired driving performance with threshold values that consider both comfort requirements and energy efficiency. The system predicts future energy needs based on current state of charge and driving patterns, allowing it to start the engine at the optimal moment that balances comfort with energy conservation.
Solution Approach 2:
The threshold for starting the internal combustion engine is dynamically adjusted based on the state of charge of the battery. When energy is abundant (high state of charge), the system allows longer purely electric operation. When energy is limited (low state of charge), the system adjusts thresholds to minimize energy loss while maintaining adequate starting comfort. This dynamic parameter adaptation resolves the contradiction between comfort and energy efficiency.
Data Source
AI summary
A control system has at least one electronic control unit for controlling an internal combustion engine in a hybrid vehicle, which records at least the vehicle speed and the driver's desired driving performance and the driving performance specified by a safety control system or a driver assistance system. The control unit is designed such that, below a pre-defined vehicle speed threshold and/or in the event of recognition of an urban area, while in a purely electric driving mode, it only engages the internal combustion engine when the current desired driving performance exceeds a pre-defined upper threshold, preferably once the maximum tractive force at the wheel for purely electric driving is at least reached.