Hybrid Vehicle Drive Power Generation Control for Efficient Energy Management
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Conventional hybrid vehicles fail to sufficiently reduce fuel consumption and exhaust emissions due to inefficient energy management, often relying on internal combustion engines during travel stoppages and low-speed travel, which leads to increased fuel consumption and emissions, especially when the state of charge (SOC) of the battery falls below control limits.
Innovation Solution
A control apparatus for drive power generators in hybrid vehicles that includes a remaining distance calculation section, an electric motor travelable distance estimation section, and a travel mode selection section, which determines the most efficient travel mode based on the remaining distance to an external charge point and the vehicle's SOC, switching between electric motor and internal combustion engine power sources to minimize fuel consumption and emissions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If the upper and lower control limit values of the SOC are lowered as the vehicle approaches the external charge point, then the charge storage device can be charged with more electric power at the external charge point, but the SOC tends to fall below the lower control limit value before arrival, causing the engine to operate at low efficiency points
Solution Approach 1:
The system calculates the remaining distance to the external charge point and estimates the electric motor travelable distance in advance. Based on these preliminary calculations, it determines whether to maintain SOC control or switch to engine travel mode before the SOC actually falls below the control limit, preventing inefficient engine operation while ensuring sufficient charging capacity at the destination.
Solution Approach 2:
The control system dynamically adjusts the travel mode selection based on real-time conditions including remaining distance to charge point, estimated electric motor travelable distance, and current SOC. This dynamic adjustment allows the system to optimize between charging maximization and fuel efficiency depending on the specific situation, rather than using fixed control limits.
2Reliability
If the motor/generator is driven by the drive power of the engine to generate electric power to maintain SOC above the lower control limit value, then the SOC is maintained higher, but the period of operating the engine cannot be shortened sufficiently, increasing fuel consumption
Solution Approach 1:
The system performs preliminary calculation of the electric motor travelable distance and remaining distance to the external charge point before the SOC actually falls below the control limit. This allows the system to proactively switch to engine travel mode or alert the driver to charge, rather than reactively running the engine just to maintain SOC, thereby reducing unnecessary fuel consumption while ensuring reliability.
3Ease of operation
If the internal combustion engine is used to travel when a predetermined period elapses after charging by the external charging device, then the output of the rotary electric machine is limited and the driver is urged to perform charging, but the engine operates at inefficient points during travel stop and low speed travel
Solution Approach 1:
The system continuously monitors the remaining distance to the external charge point and compares it with the estimated electric motor travelable distance. Based on this feedback, it provides appropriate alerts to the driver or automatically switches travel modes, ensuring the engine operates efficiently only when necessary while maintaining ease of operation through clear charging management.
Data Source
AI summary
A hybrid vehicle control ECU calculates an estimated EV travelable distance based on a minimum travel cost and a usable charge amount of a battery, when a next external charge point, at which an external power source is available for charging, is set. The minimum travel cost indicates a minimum value of electric power amount consumed by a battery when a vehicle travels a unit distance. If the estimated EV travelable distance is longer, electric motor travel is selected estimating that it is possible to reach the next external charge point. If a remaining distance is longer and a present SOC is higher than a usable SOC lower limit, hybrid travel is selected. If the present SOC is lower than the usable SOC lower limit, a constant SOC travel is selected.