Hybrid Vehicle Control System Optimizing Engine Specific Fuel Consumption
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Solution Overview
Problem
Hybrid vehicles face reduced fuel efficiency when the engine is not warmed up or operated at low speeds and loads, as the specific fuel consumption for charging batteries is high, leading to increased energy inefficiency.
Innovation Solution
A control system that determines when the required power is less than a reference power and adjusts the engine to operate at a more fuel-efficient point, generating excess power to charge the battery efficiently, thereby reducing fuel consumption by operating the engine at a high-energy efficiency point even when the required power is low.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Use of energy by moving object
If the engine operates at low speed and low load to match driver power demand, then the vehicle can operate in electric mode with motor propulsion, but the specific fuel consumption increases due to inefficient engine operation when charging the battery
Solution Approach 1:
The control system dynamically adjusts the engine operating point based on real-time conditions. When the engine is warmed up and operating conditions are favorable, the controller increases engine power output beyond immediate vehicle needs to charge the battery at efficient specific fuel consumption points. This dynamic adjustment allows the engine to operate at optimal efficiency points rather than being constrained to match low vehicle power demands directly.
Solution Approach 2:
The control system performs preliminary charging of the battery when the engine is in a favorable state (warmed up, operating at efficient specific fuel consumption points). By charging the battery in advance during efficient operating conditions, the system prepares energy storage for later use during periods when efficient charging is not possible, thereby reducing overall fuel consumption.
2Quantity of substance
If the engine is operated at high specific fuel consumption points to charge the battery, then electricity can be accumulated in the battery for later use, but fuel economy is reduced when the vehicle is propelled by the motor using this accumulated electricity
Solution Approach 1:
The control system continuously monitors engine operating conditions, specific fuel consumption, and battery state of charge. Based on this feedback, the controller determines the optimal timing and amount of battery charging. When the engine is warmed up and operating at favorable specific fuel consumption points, the system increases charging rate. When conditions are unfavorable, the system reduces or stops charging, thereby optimizing the trade-off between battery charging and fuel economy.
Solution Approach 2:
The control system changes operating parameters (engine power output, charging rate) based on engine temperature and specific fuel consumption conditions. When the engine is warmed up and operating efficiently, the system increases the charging parameter to accumulate more electricity. When conditions are unfavorable, the system adjusts parameters to maintain fuel economy, thereby optimizing the balance between electricity accumulation and fuel consumption.
3Loss of energy
If the engine operates at the most fuel efficient point irrespective of driver demand, then specific fuel consumption is minimized during engine operation, but the vehicle cannot meet variable driver power demands
Solution Approach 1:
The power supply is segmented into two sources: the engine for efficient electricity generation and the battery for immediate power delivery. The engine operates at optimal efficiency points to generate electricity, which is stored in the battery. The battery then supplies power to meet variable driver demands. This segmentation allows the engine to focus on efficient operation while the battery handles the adaptive power delivery requirements.
Solution Approach 2:
The battery acts as an intermediary between the engine and the motor. The engine generates electricity at efficient operating points and supplies it to the battery, which then delivers power to the motor as needed. This intermediary role allows the engine to operate independently at optimal efficiency points while the battery provides the necessary adaptability to meet variable driver power demands.
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 approach reduces fuel consumption and improves energy efficiency by charging the battery with electricity generated at a low fuel cost and propelling the vehicle using the stored electricity, minimizing excessive electricity generation and improving overall fuel economy.
Implementation Method 1
a generator that is driven by the engine to generate electricity
Implementation Method 2
an electric storage device that is charged by the electricity generated by the generator
Implementation Method 3
a drive motor to which the electricity is supplied from the electric storage device to generate a torque for propelling the hybrid vehicle
Implementation Method 4
an engine that generates a torque by burning fuel
Data Source
AI summary
A control system for a hybrid vehicle configured to reduce fuel consumption. A controller is configured to execute a first determination to determine that a required power is less than a reference power, and a second determination to determine that a condition to start an engine is satisfied. If the answers of the first determination and the second determination are YES, a target power of the engine is set to a predetermined power which is greater than the required power, and which can be generated by consuming smaller amount of fuel. Then, the generator is driven by the engine being operated to achieve the predetermined power, and an electric power generated by the generator to be accumulated in a battery is set to a value calculated based on a difference between the target power and the required power.