Hybrid Vehicle Controller Engine Start Threshold
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Solution Overview
Problem
Hybrid vehicles face high fuel consumption when frequently starting the engine, especially during external power supply, as the catalyst requires warming, which consumes additional fuel.
Innovation Solution
A vehicle controller is implemented to start the internal combustion engine only when the state of charge of the electric storage device reaches a lower limit value, and to set this limit lower for undrivable conditions during external power supply, reducing engine start frequency and catalyst warm-up fuel consumption.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Power
If the engine is frequently started to maintain state of charge, then the electric storage device can supply power externally, but fuel consumption increases
Solution Approach 1:
The controller dynamically adjusts the lower limit value of state of charge based on vehicle condition (drivable vs. undrivable). When the vehicle is undrivable and providing external power, a lower state of charge threshold allows the engine to start less frequently, reducing fuel consumption while still meeting external power supply demands.
2Reliability
If the engine is started frequently to warm up the catalyst, then exhaust gas purification is maintained, but additional fuel is consumed
Solution Approach 1:
The state of charge lower limit value is adjusted based on whether the vehicle is drivable. When undrivable during external power supply, the lower limit is set smaller, allowing the engine to remain off longer even if catalyst temperature needs maintenance, thereby avoiding unnecessary fuel consumption for catalyst warm-up cycles.
3Reliability
If the lower limit value is set high to ensure vehicle drivability, then the vehicle can be driven reliably, but engine start frequency increases during external power supply
Solution Approach 1:
Different state of charge lower limit values are applied to different operational contexts: a higher limit when the vehicle needs to be drivable, and a lower limit when the vehicle is undrivable and providing external power. This contextual differentiation optimizes both drivability reliability and power generation efficiency.
Solution Approach 2:
The lower limit value is not fixed but dynamically adjusted based on the vehicle's operational state (drivable vs. undrivable condition). This dynamic adjustment allows the system to optimize engine start frequency according to current operational requirements.
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 significantly reduces fuel consumption during external power supply by minimizing engine starts and catalyst warm-up, especially when the vehicle is in an undrivable condition, thereby improving power generation efficiency.
Implementation Method 1
a power generator 130, 135 that generates electric power using power of the internal combustion engine
Implementation Method 2
The internal combustion engine warms up the catalyst device using the exhaust gas
Data Source
AI summary
A vehicle includes an engine, a first motor generator that is configured to generate electric power using the power of the engine, an electric storage device that is configured to store the electric power that is generated by the first motor generator, a connection part through which the electric power that has been stored in the electric storage device is supplied to the outside of the vehicle; and an ECU that is configured to start the engine when the SOC of the electric storage device reaches a predetermined starting threshold value. The ECU sets a starting threshold value ON2 that is used when the vehicle is in an undrivable condition and electric power is being supplied to the outside of the vehicle through the connection part to a value smaller than a starting threshold value ON1 that is used when the vehicle is in a drivable condition.