Auxiliary Energy Storage Device Voltage Stabilization During Engine Cranking
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Solution Overview
Problem
Automatically stopping and starting engines in vehicles leads to voltage drops at auxiliary loads, causing diagnostic faults and electrical anomalies due to the temporary high electrical energy demand from the starter motor, which existing DC-DC boost converters are unable to effectively stabilize, especially for higher power loads.
Innovation Solution
A method involving a switch device module that decouples the primary energy storage device and starter motor from auxiliary loads during engine cranking, while coupling an auxiliary energy storage device to maintain stable voltage, ensuring the primary energy storage device and starter motor are only reconnected once the auxiliary device has taken over, thereby preventing voltage drops.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a DC-DC boost converter is used to stabilize battery voltage during engine autostart, then voltage stability for low power loads is improved, but the system becomes cost prohibitive and ineffective for higher power loads
Solution Approach 1:
The electrical system is segmented into two independent power domains: a primary ESD domain for the starter motor and a secondary ESD domain for auxiliary loads. This segmentation allows each domain to be independently managed, avoiding the need for complex DC-DC converters while maintaining voltage stability for auxiliary loads during cranking events.
Solution Approach 2:
The secondary ESD is extracted from the traditional single-battery configuration and positioned to directly serve auxiliary loads. By taking out the secondary ESD and connecting it directly to auxiliary loads through a switch device, the system eliminates the need for DC-DC conversion while providing dedicated power support during engine cranking.
2Device complexity
If the primary ESD supplies power to both the starter motor and auxiliary loads simultaneously, then system simplicity is maintained, but voltage drops occur at auxiliary loads during engine cranking
Solution Approach 1:
The switch device dynamically reconfigures the electrical system during engine cranking by opening the connection between the primary ESD and auxiliary loads, and closing the connection between the secondary ESD and auxiliary loads. This dynamic switching ensures voltage stability at auxiliary loads while maintaining overall system simplicity through automated control.
Solution Approach 2:
The switch device acts as an intermediary that temporarily redirects power flow from the primary ESD to the secondary ESD during cranking events. This intermediary mechanism allows the primary ESD to focus on starter motor power while the secondary ESD supports auxiliary loads, preventing voltage drops without complex conversion circuits.
3Power
If higher power loads are supported during engine cranking, then system capability is improved, but voltage deterioration accelerates and stabilization becomes ineffective
Solution Approach 1:
By segmenting the power system into primary and secondary ESDs with dedicated functions, the system can support higher power loads on auxiliary circuits during cranking without compromising the starter motor's power requirements. The secondary ESD is specifically sized and positioned to handle auxiliary load power demands independently.
Solution Approach 2:
The secondary ESD is pre-positioned and pre-charged to provide immediate power support to auxiliary loads before and during engine cranking. This preliminary preparation ensures that when higher power loads are demanded during cranking, the secondary ESD is ready to supply power without causing voltage deterioration.
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 effectively stabilizes voltage during engine starting events, preventing voltage sag and associated electrical issues, and is applicable to higher power loads without the cost limitations of traditional DC-DC boost converters.
Implementation Method 1
an auxiliary electrical energy storage device (ESD) is electrically coupled to one or more auxiliary loads within a predetermined delay since the active Start_ON signal was received
Implementation Method 2
A primary ESD and a starter motor are electrically decoupled from the one or more auxiliary loads only after the auxiliary ESD has been electrically coupled to the one or more auxiliary loads
Data Source
AI summary
Method for voltage stabilization during an engine starting event of a vehicle includes receiving, at a switch device module, an active Start_ON signal from a starter solenoid module indicating initiation of the engine starting event. At the switch device module, an auxiliary electrical energy storage device (ESD) is electrically coupled to one or more auxiliary loads within a predetermined delay since the active Start_ON signal was received. A primary ESD and a starter motor are electrically decoupled from the one or more auxiliary loads only after the auxiliary ESD has been electrically coupled to the one or more auxiliary loads. In response to a predetermined condition occurring while the primary ESD and the starter motor are electrically decoupled from the one or more auxiliary loads, the primary ESD and the starter motor are electrically coupled to the one or more auxiliary loads.