HEV Engine Pre-Warming Control for Accurate Start-Time Prediction
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Solution Overview
Problem
Conventional methods for controlling engine pre-warming in Hybrid Electric Vehicles (HEVs) are inefficient due to erroneous prediction of engine start time based on single State of Charge (SOC) slope, leading to wastage of energy and insufficient heat for warm-up.
Innovation Solution
A control unit that determines engine start-up time and heating time based on SOC, energy consumption, electric range, and vehicle speed at predefined intervals, allowing for continuous adjustment of the pre-warming process by initiating, discontinuing, and restarting it as needed.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If pre-warming process is initiated based on single SOC slope prediction, then engine warm-up control is implemented, but prediction accuracy is low leading to energy waste
Solution Approach 1:
The system dynamically adjusts the pre-warming control strategy by switching between different SOC slope calculation methods (first slope for initial prediction, second slope for refined prediction) based on real-time conditions. The control unit continuously monitors SOC changes and adapts the prediction approach, making the system flexible and responsive rather than static.
Solution Approach 2:
The system implements feedback control by continuously monitoring actual SOC values and comparing them with predicted values. The control unit uses the actual SOC trajectory to validate predictions and adjust the pre-warming control accordingly, ensuring the engine starts at the optimal time while minimizing energy waste from unnecessary pre-warming.
2Temperature
If pre-warming process continues until engine start, then engine is warmed up, but energy is wasted when engine starts earlier than predicted
Solution Approach 1:
The system performs preliminary SOC slope analysis to predict the optimal engine start time before actually initiating pre-warming. By calculating both first and second SOC slopes in advance, the system determines the precise moment when pre-warming should begin and end, avoiding unnecessary energy consumption from extended pre-warming while ensuring sufficient engine warmth.
Solution Approach 2:
The system changes the control parameter from a fixed pre-warming duration to a dynamic duration based on real-time SOC monitoring. The control unit adjusts the pre-warming end time parameter based on actual SOC trajectory, allowing the system to optimize the balance between achieving sufficient engine temperature and minimizing energy consumption.
3Device complexity
If conventional SOC-based prediction is used, then control is simple, but prediction is erroneous due to not considering future regenerative braking
Solution Approach 1:
The prediction process is segmented into distinct phases: first SOC slope calculation for initial prediction, and second SOC slope calculation for refined prediction. Each segment serves a specific purpose - the first provides a baseline prediction while the second incorporates future regenerative braking events to correct and refine the prediction, achieving high accuracy without overwhelming complexity.
Solution Approach 2:
The system performs preliminary analysis of future regenerative braking events before finalizing the engine start time prediction. By anticipating future charging events and incorporating them into the second SOC slope calculation, the system achieves accurate predictions without requiring complex real-time optimization during vehicle operation.
Data Source
AI summary
The present disclosure relates to a method and a control unit for controlling pre-warming process of an engine of a Hybrid Electric Vehicle (HEV). The method comprises determining start-up time of the engine. The method also comprises determining engine heating time for the engine. The pre-warming process of the engine is initiated prior to start up time of the engine. The process of pre-warming is discontinued when the determined start-up time of the engine is greater than the engine heating time and the process is restarted when the determined start-up time of the engine is less than the engine heating time and when the pre-warming process of the engine is discontinued. The above-mentioned process is reiterated at plurality of time intervals for controlling the pre-warming process of the engine which results in energy efficiency and sufficient heat for warm-up of the engine.