Engine Control Device Battery Status Determination via Swing-Back Crankshaft Rotation
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Solution Overview
Problem
Vehicles equipped with idle-stop control systems face challenges in determining battery status accurately during engine restart, leading to potential engine stop issues due to low battery power.
Innovation Solution
An engine control device that performs swing-back control by driving the crankshaft in a reverse rotation direction with a higher current value or duty ratio initially, followed by a lower setting to prevent piston over-rotation, allowing precise battery status determination and reducing power consumption.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Power
If the current value or duty ratio of supply current is increased to ensure sufficient power for engine restart, then the power supply capability is improved, but the battery power consumption increases and may lead to battery depletion
Solution Approach 1:
The patent applies dynamics by making the current value or duty ratio of supply current variable rather than constant. The controller adjusts the current value or duty ratio based on the detected battery status, allowing the system to optimize between power supply capability and power consumption dynamically. This resolves the contradiction by adapting the power delivery to actual battery conditions.
Solution Approach 2:
The patent changes the parameter of supply current (current value or duty ratio) based on battery status detection. By detecting battery voltage or other status indicators and adjusting the supply current parameters accordingly, the system ensures sufficient power for engine restart while preventing excessive power consumption that would deplete the battery.
2Reliability
If the current value or duty ratio is set high to ensure reliable engine restart, then the restart reliability is improved, but the piston may over-rotate beyond top dead center causing control precision loss
Solution Approach 1:
The patent uses dynamics by adjusting the current value or duty ratio in two distinct time periods during reverse rotation. In the first time period, a higher current value ensures reliable piston movement past top dead center. In the second time period, the current value is reduced to prevent over-rotation. This temporal dynamic adjustment resolves the contradiction between reliability and precision.
Solution Approach 2:
The patent segments the reverse rotation process into two time periods with different current values. The first time period uses higher current to ensure the piston reaches beyond top dead center, while the second time period uses lower current to maintain control precision and prevent over-rotation. This segmentation allows each phase to be optimized independently.
3Device complexity
If the battery status is not accurately determined before idle-stop control, then the system complexity is reduced, but the risk of engine stop during idle-stop increases
Solution Approach 1:
The patent applies preliminary action by detecting and determining battery status before executing idle-stop control. The controller detects battery voltage or other status indicators in advance, determines whether the battery can support the motor during restart, and only then permits idle-stop control to proceed. This preliminary check ensures reliability without significantly increasing system complexity.
Solution Approach 2:
The patent uses feedback by continuously monitoring battery status and using this information to control idle-stop functionality. The controller detects battery voltage, determines battery status based on this detection, and provides feedback control by enabling or disabling idle-stop control accordingly. This feedback mechanism ensures reliable operation while maintaining reasonable system complexity.
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
Enables precise battery status assessment and prevents piston over-rotation, ensuring reliable engine restart and efficient power management during idle-stop control.
Implementation Method 1
a motor (70) driven based on a supply current from a battery (96) drives a crankshaft (48) in a reverse rotation direction
Data Source
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AI summary
Object To detect the status of a battery by utilizing reverse rotation drive of a crankshaft at the time of engine start-up. Solving Means An engine control device (10) has an ECU (36) configured to perform, in starting an engine (E), swing-back control in which a motor (70) driven based on a supply current from a battery (96) drives a crankshaft (48) in a reverse rotation direction, and after the drive in the reverse rotation direction, drives the crankshaft (48) in a normal rotation direction. The ECU (36) has: a supply controller (128) configured to set a duty ratio of the supply current used in a first time period (T1) to a value larger than that used in a second time period (T2), the first time period (T1) extending from a time point at which the reverse rotation of the crankshaft (48) is started to a predetermined time point, the second time period (T2) extending from the predetermined time point; and a battery status determination unit (126) configured to determine a status of the battery (96) based on a state of voltage of the battery (96) in the first time period (T1).