Starter Motor Lock Determination via Dynamic Thresholds
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Solution Overview
Problem
Conventional startup control systems for internal combustion engines struggle to accurately determine when the engine is in a locked state, leading to premature shutdown of the starter motor and unnecessary power consumption, as they rely on fixed time thresholds rather than dynamic conditions such as battery state, temperature, and voltage.
Innovation Solution
A startup control device that estimates the energization current of the starter motor based on battery temperature, state of charge, and output voltage, and sets a lock determination time accordingly, determining the engine state by monitoring the engine speed, thereby preventing premature shutdown and optimizing energy usage.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a fixed time threshold is used to determine locked state, then the control system is simple, but the determination accuracy is low leading to premature shutdown
Solution Approach 1:
The patent applies dynamics by changing the fixed time threshold to a variable determination time that adapts based on battery conditions. The control device calculates different determination times according to battery temperature and SOC (state of charge), allowing the system to dynamically adjust the locked state determination criteria to match actual battery capabilities, thereby improving accuracy without requiring complex additional hardware
Solution Approach 2:
The patent changes the parameter of determination time from a fixed value to a variable value based on battery parameters (temperature and SOC). By establishing a relationship between battery conditions and appropriate determination times, the system optimizes the accuracy of locked state detection while maintaining relatively simple control logic through parameter adaptation
2Reliability
If the starter motor is energized for a longer time to ensure engine start, then startability is improved, but power consumption and load on starter motor increase
Solution Approach 1:
The patent changes the energization duration parameter based on battery conditions. By calculating optimal determination times according to battery temperature and SOC, the system extends energization time when battery conditions allow (improving startability) while preventing excessive energization when battery capacity is limited (reducing power consumption and starter motor load)
3Reliability
If the starter motor is stopped early to prevent overload, then protection is improved, but false locked state determination occurs
Solution Approach 1:
The patent adjusts the determination time parameter upward when battery conditions indicate sufficient capacity (high SOC, appropriate temperature). This allows the system to wait longer before declaring a locked state, reducing false positives while still maintaining protection by setting appropriate time limits based on calculated battery capabilities
Data Source
AI summary
A startup control device controls a starter motor. The startup control device includes lock determination circuitry and motor control circuitry. The lock determination circuitry estimates a current value supplied to the starter motor based on a temperature of a battery, a remaining electricity amount in the battery, and an output voltage of the battery when the battery supplies electricity to the starter motor, determines a threshold period of time according to the current value estimated, and determines that an internal combustion engine does not start if a rotational speed of the internal combustion engine does not exceed a referenced speed within the threshold period of time after starting supplying electricity to the starter motor. The motor control circuitry stops supplying electricity to the starter motor when the lock determination circuitry determines that the internal combustion engine does not start after starting supplying electricity to the starter motor.