Hybrid Engine Control via Battery SOC and Torque
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Solution Overview
Problem
Hybrid vehicles face challenges in controlling optimal engine operating points to minimize battery discharge and maximize charging, especially when the exhaust gas recirculation system is repeatedly started and stopped, leading to degraded fuel efficiency and increased exhaust gas emissions.
Innovation Solution
An engine operation control system that adjusts the engine operating point based on the battery state of charge (SOC) and driver requirement torque, using a controller to vary the engine operating point between optimal, EGR max, part-load max, and full-load max lines to minimize discharge and maximize charging, while ensuring driver torque requirements are met.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-generated harmful factors
If the EGR operation is repeatedly started and released based on variations of engine torque, then exhaust gas reduction is achieved, but fuel efficiency is degraded
Solution Approach 1:
The patent applies dynamics by making the engine operating point adjustable and movable across different operating regions (optimal, EGR max, part-load max, full-load max lines) based on real-time battery SOC levels and driver torque requirements. This dynamic adjustment allows the system to optimize fuel efficiency when battery charge is sufficient while ensuring adequate charging when SOC is low, thereby resolving the contradiction between exhaust gas reduction and fuel efficiency
Solution Approach 2:
The system changes the operating parameters of the engine by shifting the operating point between different characteristic lines (optimal, EGR max, part-load max, full-load max) based on battery SOC thresholds. This parameter change strategy enables the engine to operate at different efficiency points depending on battery charge levels, preventing fuel efficiency degradation while maintaining exhaust gas reduction capabilities
2Reliability
If the engine operating point is controlled to minimize battery discharge, then battery SOC is defended, but driver requirement torque may not be satisfied
Solution Approach 1:
The patent applies local quality by assigning different priorities to different operating regions based on battery SOC levels. When SOC is high, the system prioritizes fuel efficiency and battery charging by operating on the optimal line. When SOC is low, it switches to EGR max or full-load max lines that provide higher torque output. This localized optimization for different SOC conditions ensures both battery reliability and driver torque requirements are met
Solution Approach 2:
The system dynamically adjusts the engine operating point based on real-time battery SOC monitoring and driver torque requirements. By making the operating point movable between different characteristic lines, the system can satisfy driver torque demands while managing battery discharge, resolving the contradiction between battery SOC defense and torque delivery
3Loss of energy
If the engine operating point is adjusted based on battery SOC and driver torque, then fuel efficiency is enhanced, but system complexity increases
Solution Approach 1:
The patent applies segmentation by dividing the battery SOC range into multiple threshold levels (high, medium, low SOC regions) and associating each region with specific operating lines (optimal, EGR max, part-load max, full-load max). This segmented approach simplifies control logic compared to continuous optimization, enabling fuel efficiency enhancement through discrete operating region selection based on SOC thresholds and driver torque requirements
Data Source
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AI summary
An engine operation control system and method of an eco-friendly vehicle are provided to achieve optimal engine operating efficiency by changing a region for using an engine operating point based on a battery state of charge (SOC) region and a driver requirement torque. The system and method satisfy a driver requirement torque and achieve defense of battery state of charge (SOC) and optimal engine operating efficiency by changing an engine operating point based on a battery state of charge (SOC) and a driver requirement torque to an engine operating point where a battery discharge amount is minimized and a battery charging amount is maximized.