Dual Voltage Power Control for Engine Starting Reliability
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Solution Overview
Problem
In hybrid vehicles, the starter motor may fail to start the internal combustion engine when the voltage of the primary energy storage device falls below a predetermined level, leading to engine shutdown issues without user input, necessitating a solution to diagnose faults and ensure reliable engine restart.
Innovation Solution
The system employs a dual energy storage setup with a first DC voltage of 48V and a second DC voltage of 12V, utilizing a switch and DC/DC converter to apply power from the second battery to the starter motor when the first battery's voltage is insufficient, along with a fault diagnostic module to manage engine shutdown and restart based on voltage conditions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If the vehicle uses a single primary energy storage device (48V battery) for starter motor power, then the device complexity is reduced, but the reliability of engine starting deteriorates when voltage falls below predetermined level
Solution Approach 1:
The energy storage system is segmented into two separate energy storage devices: a primary energy storage device (48V battery) and a secondary energy storage device (12V battery). Each device operates independently and can be selectively engaged based on voltage conditions, allowing the system to maintain reliability while managing complexity through functional division.
Solution Approach 2:
The system changes the voltage parameter by switching between two different voltage sources (48V and 12V) based on the state of charge of the primary energy storage device. When the primary device voltage drops below a predetermined level, the system transitions to using the secondary energy storage device, ensuring reliable engine starting regardless of the primary device's voltage state.
2Reliability
If the vehicle implements a dual energy storage system with voltage monitoring and switching, then the reliability of engine starting is improved, but the device complexity increases
Solution Approach 1:
The system incorporates a voltage monitoring mechanism that continuously detects the voltage level of the primary energy storage device and provides feedback to the control logic. When the voltage falls below a predetermined threshold, the feedback signal triggers automatic switching to the secondary energy storage device, enabling reliable engine starting without requiring complex manual intervention or sophisticated control algorithms.
Solution Approach 2:
A switch serves as an intermediary component between the primary and secondary energy storage devices, controlled by a control module. This intermediary mechanism simplifies the overall system architecture by providing a straightforward on/off connection that enables seamless transition between power sources based on voltage conditions, avoiding the need for complex power electronic converters or sophisticated control systems.
3Ease of operation
If the vehicle uses the primary energy storage device exclusively for the starter motor, then the ease of operation is maintained, but the loss of information regarding voltage fault conditions increases
Solution Approach 1:
The system performs preliminary diagnostic action by monitoring the voltage level of the primary energy storage device before engine starting attempts. The fault diagnostic module proactively detects when voltage falls below a predetermined level and prepares the secondary energy storage device for engagement, ensuring that voltage fault conditions are identified and addressed before they prevent successful engine starting.
Solution Approach 2:
The system provides self-service through automatic fault detection and power source switching. The fault diagnostic module continuously monitors voltage conditions and automatically engages the secondary energy storage device when needed, eliminating the need for manual intervention or complex user decisions. This self-service approach maintains operational simplicity while preserving critical voltage fault information through automated system responses.
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
Ensures reliable engine starting and controlled shutdowns by diagnosing voltage faults and switching power sources, preventing unintended engine shutdowns and ensuring the engine can be restarted when needed.
Implementation Method 1
A DC/DC converter is configured to, when the switch is closed, convert a first DC voltage of the second energy storage device to a second DC voltage
Data Source
AI summary
In a vehicle, a first energy storage device has a first direct current (DC) operating voltage; and a second energy storage device has a second DC operating voltage. The second DC operating voltage is greater than or less than the first DC operating voltage the first DC operating voltage. A switch is connected between the first and second energy storage devices. A fault diagnostic module, while an internal combustion engine of the vehicle is shut down, diagnoses that a fault is present when a voltage of the first energy storage device is less than a predetermined DC voltage. The predetermined DC voltage is less than the first DC operating voltage. A switch control module closes the switch when the fault is diagnosed. A starter control module, when the fault is diagnosed, applies power to a starter from the second energy storage device via the switch.