Vehicle Propulsion Circuit for Low-Speed Battery Charging
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Solution Overview
Problem
Current vehicle propulsion systems charge batteries at high engine speeds, leading to engine wear, noise, and emissions when the vehicle is stationary, as they rely on high engine speed for efficient charging, which is not feasible at lower speeds.
Innovation Solution
A propulsion circuit that includes a generator, power rectifier, DC bus, propulsion battery system, and converters, allowing selective charging at lower engine speeds by switching between rectifier states and configuring battery units in series or parallel to manage voltage and reduce engine load, thereby reducing noise and emissions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If the engine is operated at high speed to charge the battery, then the charging efficiency is improved, but the engine wear, noise, and emissions increase
Solution Approach 1:
The system dynamically switches between two rectifier operating states based on real-time conditions. The controller monitors engine speed and charging needs, then selects the appropriate state: high-speed state for efficient charging when engine speed is sufficient, or low-speed state when engine speed is limited. This dynamic adaptation resolves the contradiction by allowing the system to optimize charging efficiency when possible while accepting lower efficiency only when necessary to avoid harmful effects.
Solution Approach 2:
The system changes the rectifier's operating parameters by switching between two distinct states with different characteristics. In the high-speed state, the rectifier operates with parameters optimized for maximum charging power transfer. In the low-speed state, the rectifier adjusts its parameters to function effectively at reduced engine speeds, enabling charging while minimizing engine wear, noise, and emissions. This parameter transformation allows the system to adapt to different operational constraints.
2Object-generated harmful factors
If the engine speed is reduced to decrease noise and emissions, then the harmful factors are reduced, but the battery charging efficiency decreases
Solution Approach 1:
The controller dynamically adjusts the rectifier's operation based on engine speed conditions. When engine speed drops below the optimal charging threshold, the system transitions to the low-speed state, which maintains charging functionality at reduced efficiency. This dynamic response allows the system to prioritize reducing noise and emissions when engine speed is limited, while the controller manages expectations for charging throughput accordingly.
Solution Approach 2:
The low-speed state provides a partial charging solution rather than full charging capacity. When engine speed is constrained, the system accepts reduced charging efficiency as a necessary compromise, delivering partial charging power sufficient to meet minimum requirements while avoiding the harmful effects of high-speed operation. This partial action approach resolves the contradiction by matching charging effort to available engine capacity.
3Power
If the rectifier operates in high-speed state for charging, then the charging power is sufficient, but the system cannot adapt to low engine speed conditions
Solution Approach 1:
The rectifier is designed with multi-functionality, capable of operating in two distinct states to serve different purposes. The high-speed state provides high charging power when engine conditions permit, while the low-speed state enables operation when engine speed is constrained. This universal design allows a single rectifier system to handle the full range of engine operating conditions, resolving the contradiction between power output and adaptability.
Solution Approach 2:
The system incorporates dynamic state switching that allows the rectifier to adapt its operational characteristics based on real-time engine speed conditions. The controller continuously monitors engine parameters and transitions between high-speed and low-speed states as needed, enabling the system to maintain functionality across varying operating conditions. This dynamic behavior provides the adaptability needed to resolve the contradiction between optimized power delivery and versatility.
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
Enables efficient battery charging at lower engine speeds, reducing engine wear, noise, and emissions, while maintaining propulsion capabilities, by utilizing converters and battery configuration to manage voltage and power distribution effectively.
Implementation Method 1
The generator is configured to receive an input from the engine, and to provide an alternating current (AC) output
Implementation Method 2
The power rectifier is configured to receive the AC output from the generator and provide a DC output responsive to receiving the AC output from the generator
Implementation Method 3
The at least one converter is configured to convert a direct current to an alternating current
Data Source
AI summary
A propulsion circuit for a vehicle includes an engine, a generator, a power rectifier, a direct current (DC) bus, a propulsion battery system, and at least one converter. The generator is coupled to the engine and configured to receive an input from the engine, and to provide an alternating current (AC) output. The power rectifier is configured to receive the AC output from the generator and provide a DC output responsive to receiving the AC output. The DC bus is coupled to the rectifier. The propulsion battery system is coupled to the DC bus. The at least one converter is configured to convert a direct current to an alternating current, and is coupled to the DC bus. Further, the propulsion circuit includes at least one charging component that is configured to selectably provide a charge to the battery system via at least one of the at least one converter.