Electronic Door Latch Backup Power with Current Limiting
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Solution Overview
Problem
Existing electronically controlled door latches in vehicles face challenges in maintaining power supply during long-term parking situations or power failures, particularly when used with devices that require electrical operation, as supercapacitors discharge rapidly and current solutions do not effectively manage current flow to ensure access to the vehicle.
Innovation Solution
An electronically controlled door latch arrangement incorporating a supercapacitor group connected via a current limiter, which limits current flow to maintain charge and provide auxiliary power when the main power source is unavailable, using a current limiter to interrupt the connection above a predetermined threshold, ensuring the supercapacitor group does not discharge completely.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If supercapacitors are used to provide backup power to the eLatch during long-term parking, then the eLatch can operate during power failures, but the supercapacitor discharges rapidly and cannot maintain power supply for extended periods
Solution Approach 1:
A current limiter is introduced as an intermediary component between the supercapacitor and the eLatch. This current limiter actively regulates and restricts the discharge current from the supercapacitor to a safe, controlled level, preventing rapid discharge while ensuring sufficient power delivery to the eLatch during backup operations.
Solution Approach 2:
The system changes the current parameter by implementing dynamic current limiting. The current limiter monitors and adjusts the discharge current based on predefined thresholds, transforming the uncontrolled rapid discharge into a controlled, sustained discharge that can maintain power supply for extended parking periods.
2Ease of operation
If the supercapacitor group is continuously connected to the external device, then power is always available, but the charge in the supercapacitor group is lost during long-term parking
Solution Approach 1:
The current limiter incorporates feedback mechanisms that continuously monitor the charge state and current flow from the supercapacitor. Based on this feedback, the system dynamically adjusts the discharge rate to balance power availability with charge preservation, preventing complete discharge during long-term parking while maintaining operational readiness.
Solution Approach 2:
The current limiter implements periodic monitoring and control cycles, repeatedly assessing the charge state and adjusting current flow accordingly. This periodic action ensures that the supercapacitor maintains sufficient charge over extended periods while still providing power when needed.
3Ease of operation
If mechanical Bowden cables or levers are used for the eLatch, then the door can be opened without power, but the system becomes more complex and less reliable
Solution Approach 1:
The patent replaces mechanical Bowden cables and levers with an electronically controlled system. Instead of mechanical linkages, the eLatch uses electronic actuators controlled by a control unit, eliminating the need for complex mechanical backup mechanisms while maintaining or improving reliability through electronic control and diagnostic capabilities.
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 solution maintains sufficient power to operate external devices like electronically actuated door handles, even in long-term parking or power failure scenarios, by managing current flow to preserve supercapacitor charge and ensure reliable access to the vehicle.
Implementation Method 1
a supercapacitor group (3), wherein the supercapacitor group (3) is galvanically conductively connected to the external device (2) via the interconnected current limiter (4)
Implementation Method 2
the current limiter (4) is configured to interrupt a current to the external device (2) from the supercapacitor group (3) at a predetermined current limit value
Data Source
Figure 1~2
AI summary
The invention relates to an electronically controlled door latch arrangement for a vehicle (17), the arrangement comprising an external device (2), a supercapacitor group (3) and a current limiter (4), wherein the supercapacitor group (3) is galvanically conductively connected to the external device (2) via the interconnected current limiter (4), the supercapacitor group (3) is chargeable with a main supply power provided by a main power source (5) of the vehicle (17) during a normal operating state, such that in the event of an unavailability of the main supply power, an auxiliary supply power is provided to the external device (2) employing the supercapacitor group (3) during a backup operating state, and the current limiter (4) is configured to interrupt a current to the external device (2) from the supercapacitor group (3) at a predetermined current limit value, such that the charge in the supercapacitor group (3) is maintained. In this way an easy, cheap and reliable solution for feeding an electronically controlled door latch with power in long term parking situations is provided.