Hybrid Vehicle Charging Control for NV Mitigation
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Solution Overview
Problem
Existing hybrid vehicle systems face challenges in efficiently increasing the power storage amount of a power storage device while minimizing noise and vibration (NV) characteristics, particularly during low travel loads where engine operation is inefficient and worsens NV characteristics.
Innovation Solution
A hybrid vehicle system with an electronic control unit that switches between strong and weak charging modes based on travel load conditions, promoting charging when necessary and suppressing it during low loads, and automatically switching to strong charging if the weak mode persists or if the power storage amount decreases, ensuring efficient power storage increase.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If charging of the power storage device is promoted by increasing the output of the internal combustion engine, then the power storage amount is increased quickly, but noise and vibration (NV) characteristics worsen
Solution Approach 1:
The patent applies parameter changes by switching between two distinct charging modes (strong charging mode and weak charging mode) based on travel load conditions. In strong charging mode, the engine output is increased to charge the power storage device quickly, while in weak charging mode, the engine output is reduced to minimize NV characteristics. This dynamic parameter adjustment resolves the contradiction between charging speed and NV performance.
2Productivity
If the internal combustion engine operates at low travel load to charge the power storage device, then charging is enabled, but charging efficiency decreases
Solution Approach 1:
The patent implements parameter changes by monitoring travel load conditions and switching between charging modes accordingly. When travel load is large, the system operates in strong charging mode with high engine output for efficient charging. When travel load is small, the system switches to weak charging mode with reduced engine output, preventing inefficient energy conversion and maintaining optimal charging efficiency across different operating conditions.
3Productivity
If charging promotion control is continuously applied regardless of travel load, then the power storage amount increases, but NV characteristics and energy efficiency worsen during low load periods
Solution Approach 1:
The patent applies dynamics by making the charging control system adaptive and responsive to changing travel load conditions. The electronic control unit continuously monitors travel load and dynamically switches between strong charging mode and weak charging mode. This dynamic control ensures that charging promotion is applied when needed (high travel load) while suppressing charging when travel load is low, thereby maintaining power storage amount increase without continuously degrading NV characteristics and energy efficiency.
4Productivity
If the engine output is increased for rapid charging, then the power storage device charges faster, but energy efficiency decreases
Solution Approach 1:
The patent resolves this contradiction through parameter changes by implementing two distinct engine output levels corresponding to strong charging mode and weak charging mode. The system selects the appropriate output level based on travel load conditions, achieving high charging rates when energy efficiency is less critical (high travel load) and maintaining energy efficiency when travel load is low. This conditional parameter adjustment optimizes the trade-off between charging rate and energy efficiency.
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 enhances efficiency and mitigates NV issues by optimizing charging based on travel load conditions, ensuring the power storage amount is increased as requested by the user even during low travel loads, thereby improving overall system performance.
Implementation Method 1
a power generation device (6, 10), each comprising a stator and a rotor, the power generation device (6, 10) being configured so as to generate charging power of the power storage device (16) by using an output of the internal combustion engine (2)
Data Source
AI summary
Provided are a hybrid vehicle and control method thereof. The hybrid vehicle has a power storage device, an internal combustion engine, a power generation device, an input device and an electronic control unit. The electronic control unit is configured to control charging of the power storage device by the power generation device in such a manner that charging of the power storage device is promoted when an increase of the power storage amount is requested through the input device, and in a state where an increase of the power storage amount has been requested through the input device, to suppress charging of the power storage device when a travel load is small, as compared to when the travel load is large, and to mitigate suppression of charging of the power storage device when a predefined condition is met during suppression of charging of the power storage device.