Vehicle Control Apparatus Managing SOC Thresholds for Fuel Economy
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Solution Overview
Problem
Existing vehicle systems prioritize torque assist mode over delivering electric power to the electrical load, leading to inefficiencies in fuel economy as they do not secure power delivery to the load, thereby missing opportunities to improve fuel efficiency.
Innovation Solution
A control apparatus is introduced that includes a stop controller for idle stop mode, a start controller for restarting the engine, a power generation controller to maintain battery charge, a torque assist controller for assisting vehicle movement, and an SOC determiner to manage state of charge thresholds, ensuring electric power is prioritized for the electrical load and used efficiently.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Force
If the system prioritizes torque assist mode over delivering electric power to the electrical load, then the vehicle movement assistance is improved, but the fuel economy deteriorates due to missed opportunities to supply electric power to the electrical load
Solution Approach 1:
The system dynamically adjusts the SOC threshold parameter based on vehicle speed and torque requirements. When vehicle speed is high and torque demand is low, the threshold is raised to prioritize electric power delivery to the load. When vehicle speed is low or torque demand is high, the threshold is lowered to permit torque assist mode, thereby optimizing fuel economy across different operating conditions.
Solution Approach 2:
The control system continuously monitors vehicle operating conditions (speed, torque demand, battery SOC) and dynamically switches between torque assist mode and electric power delivery mode. This dynamic adjustment allows the system to capture fuel economy opportunities by delivering electric power to the load when conditions permit, while still providing torque assist when necessary for vehicle performance.
2Use of energy by moving object
If the system enters idle stop mode to save fuel, then the fuel economy is improved, but the reliability deteriorates due to potential power supply issues for restarting the engine
Solution Approach 1:
The system performs preliminary charging of the storage battery during vehicle operation by controlling the rotating electrical machine to generate electric power and charge the battery. This preliminary action ensures that sufficient electric power is stored before idle stop mode is engaged, guaranteeing reliable engine restart capability while maximizing fuel economy benefits during the idle stop period.
Solution Approach 2:
The control system continuously monitors battery SOC and provides feedback to the idle stop control. When SOC falls below a predetermined threshold, the system automatically cancels or prevents entry into idle stop mode, ensuring that the engine can always be restarted reliably. This feedback mechanism maintains restart reliability while still capturing fuel economy opportunities when battery charge is sufficient.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
This solution enhances fuel economy by ensuring electric power is delivered to the electrical load before engaging torque assist mode and maintains the internal combustion engine in idle stop mode when possible, improving power efficiency and extending the idle stop duration.
Implementation Method 1
a rotating electrical machine which selectively works in a torque assist mode to assist in moving a vehicle and a power generation mode to generate electricity
Implementation Method 2
a storage battery which is charged by electric power delivered from the rotating electrical machine
Data Source
AI summary
A control apparatus is used in a vehicle equipped with an internal combustion engine, a rotating electrical machine, and a storage battery. The control apparatus stops the engine when a state of charge (SOC) of the storage battery is higher than a lower limit, and an automatic stop condition is met and also restarts the engine when the SOC of the storage battery is lower than the lower limit, and an automatic restart condition is met. The control apparatus also controls operation of the rotating electrical machine to generate electricity to increase the SOC above a target SOC and also actuates the rotating electrical machine to assist in driving the vehicle when the SOC is higher than a torque assist enable SOC. The target SOC is set higher than the lower limit. The torque assist enable SOC is set higher than the target SOC. This improves the fuel economy.