Hybrid Vehicle Drive Control Using Electrical Path Power Split
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Solution Overview
Problem
The existing vehicle drive devices do not always control the engine operating point to an optimal fuel efficiency point, leading to decreased fuel efficiency when the operating point deviates from the optimal point.
Innovation Solution
A vehicle drive device with a first power source, a hydraulic transmission, a torque splitter, and an electronic control device that controls the torque split ratio and engine operating point by adjusting the electrical path amount, using the second rotating machine as a second power source when the engagement device is engaged.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Use of energy by moving object
If the engine operating point is controlled to an optimal fuel efficiency point, then the fuel efficiency of the engine is improved, but the overall fuel efficiency of the vehicle may not be maximized due to power transmission path constraints
Solution Approach 1:
The power transmission system is segmented into multiple independent power sources (engine and second rotating machine) with separate control. The engine can be controlled to optimal fuel efficiency points while the second rotating machine compensates for power deficits, allowing independent optimization of each component's fuel efficiency contribution to the overall vehicle performance.
Solution Approach 2:
The system dynamically changes operating parameters by switching between different power source combinations and adjusting the torque split ratio. When the engagement device is engaged, the second rotating machine is activated to supplement or replace engine power, enabling the engine to operate at more efficient points while maintaining required vehicle power output.
2Use of energy by moving object
If the engagement device is in an engaged state and the second rotating machine is used as a second power source, then the overall fuel efficiency of the vehicle is improved, but the device complexity increases
Solution Approach 1:
The second rotating machine serves multiple functions: it acts as a power source to improve fuel efficiency when engaged, provides torque to the second output shaft for power distribution, and can replace the engine under certain conditions. This multi-functionality justifies the added complexity by delivering significant fuel efficiency improvements through a single versatile component.
Solution Approach 2:
The engagement device acts as an intermediary that selectively connects or disconnects the second rotating machine from the power transmission path. This mediator component enables the system to switch between simple engine-only operation and complex dual-power-source operation, allowing the system to incur complexity only when the fuel efficiency benefits are realized.
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
The device improves the overall fuel efficiency of the vehicle by determining whether the fuel efficiency is improved by operating the first rotating machine to generate electricity and using the second rotating machine as a power source, and adjusting the engine operating point accordingly.
Implementation Method 1
a hydraulic transmission that transmits power from the first power source via a fluid
Implementation Method 2
operating the first rotating machine to generate electricity
Implementation Method 3
using the second rotating machine as a second power source
Data Source
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AI summary
It is determined whether fuel efficiency of a vehicle is improved by operating a first rotating machine to generate electricity to such an extent that an electrical path amount becomes a desired electrical path amount for controlling an operating point of an engine to a desired operating point and driving and operating a second rotating machine as a second power source, the electrical path amount being a magnitude of electric power in an electrical path through which the electric power is transferred between the first rotating machine and the second rotating machine. When the electronic control device determines that the fuel efficiency of the vehicle is improved, the first rotating machine is operated to generate electricity to such an extent that the electrical path amount becomes the desired electrical path amount and the second rotating machine is driven and operated as the second power source.