Vehicle Door Latch Control with Impact Sensor
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Solution Overview
Problem
Conventional powered vehicle door latches are prone to unintentional or accidental triggering, leading to unwanted unlatching of the door.
Innovation Solution
Incorporation of a variable resistance bend sensor and capacitive sensors in the exterior door handle to detect side impacts and user presence, respectively, which prevents the powered latch from unlatching unless both conditions are met within a predefined time interval upon actuation of the unlatch switch.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If an electrical unlatch switch is added to enable powered door unlatching, then ease of operation is improved, but reliability deteriorates due to risk of unintentional triggering
Solution Approach 1:
A control unit is introduced as an intermediary between the unlatch switch and the powered latch mechanism. The control unit processes signals from the unlatch switch and determines whether to activate the powered latch based on additional conditions (impact detection), thereby mediating between user input and system response to prevent unintentional unlatching
Solution Approach 2:
The system incorporates feedback from impact sensors that continuously monitor the door handle state. This feedback is sent to the control unit, which uses the impact information to determine whether to permit unlatching when the switch is activated, creating a closed-loop control system that enhances reliability
2Reliability
If impact sensors are added to detect side impacts and prevent accidental unlatching, then reliability is improved, but device complexity increases
Solution Approach 1:
The control unit performs multiple functions: it processes unlatch switch signals, receives and evaluates impact sensor data, determines unlatch permission based on impact conditions, and controls the powered latch activation. By making the control unit multi-functional, the system avoids adding separate dedicated circuits for each function, thereby limiting the increase in device complexity
Solution Approach 2:
The control unit combines the switch signal processing and impact detection evaluation functions into a single integrated control mechanism. Rather than having separate systems for switch control and impact sensing, the patent merges these functions into one control unit that handles both inputs and makes the unified decision regarding latch activation
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
Prevents unwanted unlatching by ensuring that only intentional user actions trigger the door opening, reducing accidental releases and enhancing safety and reliability.
Implementation Method 1
A variable resistance bend sensor extends along the outer side of the exterior door handle such that an impact force applied to the outer side of the handle changes an electrical resistance of the bend sensor
Implementation Method 2
a capacitive sensor on the exterior door handle capable of detecting a user's hand disposed in the gap
Data Source
AI summary
A vehicle door includes a powered latch configured to selectively retain the door in a closed position when the powered latch is latched, and permits the door to be opened when the powered latch is unlatched. The vehicle door further includes an exterior door handle having an outer side that faces away from the door structure, and an inner side that is spaced apart from an outer surface of the door to define a gap. A force sensor on the exterior door handle detects impact forces on the handle. The door also includes an unlatch switch that can be actuated by a user to request unlatching of the powered latch. A controller is configured to deny an unlatch request generated by actuation of the unlatch switch if the force sensor detects an impact on the exterior handle.