Dynamic Battery Thresholds for Stop-Start Engine Control
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Solution Overview
Problem
Existing engine systems for automatic stopping and starting based on battery state of charge (SOC) and temperature thresholds limit opportunities for fuel conservation, especially with new batteries, as they require high SOC and temperature levels for engine cranking performance, restricting frequent automatic engine stopping and starting.
Innovation Solution
Adjusting the battery SOC and temperature thresholds dynamically based on automatic engine cranking times, lowering thresholds when cranking times are short to allow more frequent engine stops and raising them when cranking times are longer to maintain performance, thereby enabling more frequent automatic engine stopping and starting.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If high battery SOC and temperature thresholds are used for automatic engine stopping and starting, then engine cranking performance is ensured, but opportunities for fuel conservation are reduced
Solution Approach 1:
The patent applies dynamics by making the battery SOC and temperature thresholds adjustable rather than fixed. The control system dynamically modifies these thresholds based on battery health status (SOH), allowing lower thresholds when battery health is high (new battery) and higher thresholds when battery health is low (aged battery). This resolves the contradiction by adapting the operating parameters to current system conditions, enabling fuel conservation opportunities when battery performance allows while maintaining cranking reliability when battery performance degrades.
Solution Approach 2:
The patent changes the parameters of battery SOC and temperature thresholds based on battery health status. When battery health is determined to be above a threshold, the system permits lower SOC thresholds (e.g., 20-40% instead of 70-80%) and/or lower temperature thresholds, thereby increasing opportunities for automatic engine stopping. When battery health falls below the threshold, the system raises these thresholds to ensure reliable cranking. This parameter adaptation directly resolves the contradiction between fuel conservation and cranking performance.
2Reliability
If fixed battery SOC and temperature thresholds are used, then engine starting reliability is maintained, but adaptability to battery aging and new battery conditions is reduced
Solution Approach 1:
The patent implements feedback by continuously monitoring battery health status (SOH) and using this information to adjust the SOC and temperature thresholds for automatic engine stopping and starting. The control system receives feedback about battery condition, processes this information, and modifies the operating thresholds accordingly. This closed-loop approach maintains engine starting reliability across the entire battery life cycle while adapting to both new and aged battery conditions, resolving the contradiction between fixed reliability and adaptability.
Solution Approach 2:
The patent applies preliminary action by assessing battery health status in advance and pre-adjusting the SOC and temperature thresholds before automatic engine stopping decisions are made. The system proactively modifies these parameters based on predicted battery performance needs, ensuring that reliability is maintained while maximizing fuel conservation opportunities appropriate to the battery's current state. This preliminary adjustment resolves the contradiction by preparing the system in advance for varying battery conditions.
Data Source
AI summary
Systems and methods for operating a vehicle that includes an engine that may be automatically stopped and started are described. In one example, thresholds for allowing or inhibiting of automatic engine stopping and starting may be adjusted in response to an automatic engine cranking time. Additionally, automatic engine stopping may be inhibited during some conditions.