Hybrid Engine Start-Stop Threshold Control for External Load Management
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Solution Overview
Problem
Existing engine control systems in hybrid electric vehicles fail to efficiently manage battery state of charge (SOC) and power loads from external accessories, leading to intermittent power losses and wear on electrical devices, which can affect battery life and fuel consumption.
Innovation Solution
A controller system that dynamically adjusts the SOC thresholds based on detected loads and user input, postponing engine start and stop events to maintain battery charge and prevent power interruptions, while considering the magnitude and type of current drawn by accessories.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Use of energy by moving object
If the engine is automatically started and stopped to meet energy needs, then fuel consumption is optimized, but battery state of charge stability deteriorates when external loads are present
Solution Approach 1:
The engine control system dynamically adjusts the SOC threshold based on detected load conditions. When an external load is detected drawing power from the battery, the system lowers the SOC threshold at which engine start is initiated, allowing the engine to run longer and recharge the battery to compensate for the external power draw. This dynamic adjustment resolves the contradiction by adapting engine operation to maintain battery stability while optimizing fuel consumption.
Solution Approach 2:
The control system continuously monitors battery SOC levels and external load conditions, using this feedback to adjust engine start/stop decisions. When the system detects that an external load is drawing power from the battery, it receives feedback about the declining SOC and responds by initiating engine start at a higher SOC threshold than normal, thereby maintaining battery stability while managing fuel consumption efficiently.
2Stability of the object's composition
If the SOC threshold is lowered to accommodate external power loads, then battery stability is maintained, but engine start frequency increases leading to higher fuel consumption
Solution Approach 1:
The system dynamically adjusts the SOC threshold based on the presence and magnitude of external loads. Rather than using a fixed threshold, the threshold becomes a variable parameter that adapts to conditions - lowering it only when necessary to maintain battery stability during external power draws, and raising it back to normal levels when loads are removed, thereby minimizing unnecessary engine starts and fuel consumption.
Solution Approach 2:
The control system changes the SOC threshold parameter in response to detected load conditions. When external loads are present, the threshold parameter is adjusted to a lower value to allow more aggressive battery discharge; when loads are absent, the threshold returns to its normal higher value. This parameter change strategy resolves the contradiction by optimizing both battery stability and fuel consumption based on real-time conditions.
3Use of energy by moving object
If the engine starts at higher SOC thresholds to reduce start frequency, then fuel consumption decreases, but battery power stability deteriorates under external load
Solution Approach 1:
The system employs dynamic threshold adjustment that responds to external load detection. When loads are present, the SOC threshold for engine start is lowered to maintain battery stability; when loads are absent, the threshold increases to reduce engine start frequency. This dynamic behavior resolves the contradiction by adapting engine operation to maintain reliability while optimizing fuel consumption.
Solution Approach 2:
The control system uses feedback from load detection and SOC monitoring to make intelligent engine start decisions. The feedback loop detects when external loads are drawing power and adjusts the engine start threshold accordingly, preventing battery instability while avoiding unnecessary engine starts during normal operation, thus resolving the contradiction between fuel efficiency and power stability.
Data Source
AI summary
An engine control system for a vehicle includes a controller that initiates a start of the engine in response to a state of charge (SOC) of a battery falling below an engine start threshold, initiates a stop of the engine in response to the SOC exceeding an engine stop threshold, and adjusts a value of the engine start threshold based on whether a load remote from the vehicle is drawing power from the battery.