Engine Auto Start Electrical Load Subsystem Sequencing
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Solution Overview
Problem
During engine auto-starts in micro-hybrid vehicles, existing systems face challenges in efficiently managing the reactivation of electrical load subsystems to prevent voltage drops and ensure priority-based restoration of essential systems without conflicting with driver requests, particularly when the alternator or integrated starter generator is not fully operational.
Innovation Solution
A method where a controller sequentially enables subsets of electrical load subsystems based on predefined engine speed ranges and output thresholds, categorizing them by priority to balance system performance and customer expectations, ensuring that critical systems are restored first as the engine speed increases, and only enabling them when the alternator or integrated starter generator can handle the demand.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If all electrical load subsystems are enabled simultaneously during engine auto-start, then system restoration is faster, but voltage drops occur and system stability deteriorates
Solution Approach 1:
The patent divides electrical load subsystems into multiple priority groups (first priority, second priority, third priority) and enables them sequentially based on engine speed thresholds. This segmentation prevents simultaneous activation of all loads, avoiding voltage drops while ensuring critical systems are restored first.
Solution Approach 2:
The system pre-establishes priority categories and enabling thresholds before engine auto-start occurs. During startup, subsystems are enabled in predetermined sequences based on pre-defined engine speed ranges, ensuring stable voltage recovery before higher-power loads are activated.
2Reliability
If critical subsystems are enabled first during auto-start, then system priority requirements are met, but non-critical subsystems experience delayed restoration
Solution Approach 1:
The system dynamically adjusts which subsystems are enabled based on real-time engine speed measurements. As engine speed increases and exceeds predefined thresholds, additional subsystems are progressively enabled, transitioning from critical-only restoration to comprehensive restoration without manual intervention.
Solution Approach 2:
The patent uses engine speed as a changing parameter to control subsystem enabling. Different subsystems are activated when engine speed enters specific ranges (e.g., first threshold, second threshold, third threshold), allowing the system to adapt restoration behavior to available power generation capacity.
3Ease of operation
If the controller manages all subsystem enabling, then priority-based control is achieved, but control complexity increases
Solution Approach 1:
The controller logic is segmented into discrete threshold-based decision points. Each threshold corresponds to a specific subsystem priority level, simplifying the control algorithm to a series of if-then statements based on engine speed comparisons, rather than complex prioritization logic.
Data Source
AI summary
An automotive vehicle includes an engine, a plurality of electrical load subsystems, and at least one controller. During an auto start of the engine, the at least one controller detects a starter disengage condition. In response to detecting the starter disengage condition, the at least one controller periodically determines a value of an operating parameter associated with the vehicle, causes a first subset of the electrical load subsystems to be enabled when the value of the operating parameter falls with a first predefined range of values, and causes a second subset of the electrical load subsystems to be enabled when the value of the operating parameter falls within a second predefined range of values.