DC-DC Converter Output Current Threshold Control for Engine Starting
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
In vehicles with a starter motor that starts an engine, the power consumption by the starter motor and accessories can lead to a shortfall in the output of the DC-DC converter, affecting engine start performance, especially when high power is consumed by accessories during engine starting.
Innovation Solution
A control device that includes an engine, a starter motor, a direct-current-to-direct-current converter, and a controller, which switches between engine-driven and engine-stopped traveling modes, executes output limit control to lower the output current by reducing the output voltage of the DC-DC converter when the current exceeds a threshold, and initiates boost permitting control to increase the output limit threshold during engine start, ensuring reliable engine starting.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Power
If the DC-DC converter supplies power to both the starter motor and accessories during engine starting, then the power consumption increases, but the output current is limited by the converter's capacity, causing a shortfall in power supply
Solution Approach 1:
The patent dynamically adjusts the output current threshold of the DC-DC converter based on operating conditions. During engine starting, the controller increases the output current threshold to allow higher current flow to the starter motor, ensuring reliable engine start while preventing overheating during normal operation
Solution Approach 2:
The patent changes the output current threshold parameter of the DC-DC converter from a fixed value to a variable value that adapts to different operating modes. The threshold is increased during engine starting and decreased during normal operation, optimizing power delivery for each condition
2Reliability
If the DC-DC converter maintains a fixed output current threshold, then the converter operates safely within limits, but the starter motor cannot receive sufficient power during engine starting
Solution Approach 1:
The system transitions from a static output current threshold to a dynamic threshold that changes based on the operating state. The controller detects engine starting conditions and temporarily increases the threshold, allowing the converter to safely deliver higher power during critical moments while maintaining safety limits during normal operation
Solution Approach 2:
The controller prepares the DC-DC converter for high-power output by pre-adjusting the output current threshold before engine starting occurs. This preliminary adjustment ensures the converter is ready to immediately supply the required power to the starter motor when starting is detected
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
The control device ensures reliable engine starting by preventing output shortfalls from the DC-DC converter, allowing for increased power supply to the starter motor and accessories, thereby improving engine start performance.
Implementation Method 1
The direct-current-to-direct-current converter is configured to supply an electric power of the battery to the starter motor, and is configured to lower an output voltage to be supplied to the starter motor
Data Source
AI summary
A control device includes an engine, a starter motor configured to perform engine start, a direct-current-to-direct-current converter, a battery coupled to the starter motor with the direct-current-to-direct-current interposed therebetween, and a controller. The controller is configured to execute control of switching between first and second traveling modes. The direct-current-to-direct-current converter is configured to supply an electric power of the battery to the starter motor, and to lower an output voltage to be supplied thereto. The controller is configured to execute output limit control of lowering the output voltage to lower the output current, in a case where an output current of the direct-current-to-direct-current converter becomes equal to or higher than a threshold. The controller is configured to initiate boost permitting control when initiating the engine start in association with switching from the second to first traveling mode. The boost permitting control makes the threshold higher than a usual threshold.