Parallel Resistor and Current Control Device for Vehicle Starter
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
The existing starting current limiting systems for motor vehicles face challenges in managing high starting currents during warm starts, which can lead to voltage drops at the battery poles, affecting comfort consumers, and require expensive power semiconductor switches to prevent semiconductor switch breakdown.
Innovation Solution
A starting current limiting system that uses a parallel circuit with a current intensity control device and a low-impedance resistor to limit the starting current, where the resistor handles the initial high current during warm starts, and the current control device takes over after the start-up phase, preventing semiconductor switch overload and maintaining power supply to comfort consumers.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If a single current control device with semiconductor switches is used to limit starting current, then the device complexity is reduced, but the semiconductor switches can be overloaded and break down due to high starting currents of more than 500 A
Solution Approach 1:
The current control function is segmented into two parallel branches: one with a semiconductor switch for normal current control and another with a diode for handling high starting currents. This segmentation allows each component to operate within its optimal current range, preventing semiconductor overload while maintaining system simplicity
Solution Approach 2:
The diode branch acts as an intermediary that activates during high starting current conditions to protect the semiconductor switch. The diode provides a parallel current path that limits the current through the semiconductor switch to safe levels during engine starting, while being transparent during normal operation
2Object-affected harmful factors
If the starting current is limited using a resistor in series with the starter, then the voltage drop at battery poles is reduced, but the current through the resistor remains limited even during cold starts when full current is not necessary
Solution Approach 1:
The system dynamically adapts its current limitation behavior based on operating conditions. During cold starts, the semiconductor switch closes to bypass the resistor, allowing full current flow when needed. During warm starts, the semiconductor switch remains open and the resistor limits current to prevent voltage drops, providing adaptive current management
3Reliability
If expensive power semiconductor switches are used to prevent breakdown during warm starts, then the reliability is improved, but the manufacturing cost increases significantly
Solution Approach 1:
The diode is used as a simple, inexpensive protective element that sacrificially handles the high starting current stress. Instead of requiring expensive high-current-rated semiconductor switches, the system uses a cheap diode to absorb the stress during starting, allowing the use of lower-cost semiconductor switches for normal operation
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 system effectively limits starting currents, preventing voltage drops and protecting semiconductor switches, while ensuring continuous power supply to comfort consumers with minimal structural effort and cost, using a combination of a resistor and current control device.
Implementation Method 1
a parallel circuit consisting of a branch with a current intensity control device and a branch with an electrical resistance is arranged between the first connection and the second connection
Implementation Method 2
which preferably has semiconductor switches, so-called 'alloying through' of the semiconductor switches can occur in the event of a warm start
Data Source
Figure 1~3
Figure 4~5
Figure 6
AI summary
The current limiting system (2) has current control device (12) whose primary electrical terminal (4) is connected with terminal of battery (8) of motor vehicle, and secondary electrical terminal (6) is connected to starter (10). An electric resistor (14) is connected parallel to current control device, between the primary and secondary electrical terminals, such that the starter current is passed through the electric resistor during start of motor vehicle, and is passed through the current control device after the start of motor vehicle. An independent claim is included for method for operating starting current limiting system.