Predictive Battery Voltage Control for Reliable Engine Restart
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Solution Overview
Problem
Automatic engine control devices face challenges in accurately predicting the minimum voltage of a vehicle's battery during engine idle stop conditions, leading to difficulties in restarting the internal combustion engine due to voltage drops below a predetermined threshold.
Innovation Solution
The implementation of an automatic engine control device that includes a battery, starter, voltage detection means, and resistance calculation mechanisms to predict the discharging current and voltage, ensuring the battery voltage remains above the threshold for reliable engine restarts by calculating the starter total resistance value and using this data to judge the permission for engine restarts.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Duration of action of stationary object
If the automatic engine stop control is executed to extend idle stop period, then environmental benefits improve, but the battery terminal voltage decreases below the predetermined voltage threshold making engine restart difficult
Solution Approach 1:
The system performs preliminary actions by detecting battery voltage and SOC before engine restart, calculating the minimum predicted voltage, and judging whether restart is permitted based on these advance assessments. This prevents voltage drops below the threshold by acting beforehand rather than reactively.
Solution Approach 2:
The system continuously monitors battery voltage and SOC, feeds this information back to the control unit, which then adjusts restart permission decisions. The feedback loop ensures that engine restart is only permitted when battery conditions are sufficient, maintaining reliability while enabling extended idle stop periods.
2Ease of operation
If the battery supplies large current to the starter during engine restart, then the engine can be restarted, but the terminal voltage of the battery decreases drastically reducing available capacity
Solution Approach 1:
The system calculates the minimum predicted voltage before permitting engine restart by considering the large current demand of the starter. This preliminary calculation ensures that sufficient battery capacity remains after the restart operation, preventing excessive capacity loss while maintaining restart capability.
Solution Approach 2:
The system uses a predictive model to calculate minimum voltage based on battery characteristics and operating conditions, creating a virtual representation of voltage behavior. This copied model allows the system to assess restart feasibility without actually performing the high-current discharge operation first.
3Device complexity
If conventional judgment methods are used to determine engine restart permission, then the control system remains simple, but the accuracy of predicting minimum battery voltage decreases
Solution Approach 1:
The system improves prediction accuracy by utilizing multiple parameters including battery voltage, SOC, temperature, and discharge characteristics. By changing from simple threshold-based judgment to multi-parameter predictive calculation, the system achieves higher precision while maintaining acceptable control complexity through efficient computation algorithms.
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 solution ensures high accuracy in predicting battery voltage during engine restarts, preventing voltage drops below the threshold, thereby guaranteeing reliable engine restarts and extending engine idle stop periods.
Implementation Method 1
a voltage detection means detects a voltage of the battery
Implementation Method 2
The battery charges and discharges electric power
Implementation Method 3
The starter works to start the internal combustion engine when receiving electric power supplied from the battery
Data Source
AI summary
An ECU in an automatic engine control device predicts a maximum discharging current to be supplied from a battery to a starter during a next restart of the engine based on a present voltage, an internal resistance value of the battery, and a starter total resistance value during automatic engine stop. The ECU further predicts a minimum voltage of the battery during a period until the next restart of the engine based on the present voltage, the present internal resistance value of the battery, and the predicted maximum discharging current. The ECU judges whether or not execution of the next restart of the engine during the automatic engine stop based on the predicted minimum voltage of the battery.