Active Hood Impact Sensor Using Optical Fiber and Membrane Switch
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Solution Overview
Problem
Existing active hood systems fail to operate effectively when a pedestrian crashes with parts of the vehicle that do not have a mounted sensing sensor, leading to inadequate protection against secondary crashes between the pedestrian's head and engine components.
Innovation Solution
An impact sensor system comprising optical fiber sensors and a membrane switch, disposed between an energy absorber and a back beam in the bumper, which senses impact forces and determines the crash position, enabling the active hood system to distinguish between pedestrian and object impacts and precisely identify crash locations to minimize damage.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a sensing sensor is mounted on a specific part of the front of the vehicle, then the sensor can detect crashes at that location, but the active hood system fails to operate when the pedestrian crashes with parts of the front of the vehicle where the sensing sensor is not mounted
Solution Approach 1:
The sensing sensor is divided into multiple sensing regions (first sensing region, second sensing region, third sensing region, fourth sensing region) corresponding to different parts of the bumper. Each region independently detects crashes in its specific area, ensuring comprehensive coverage of the entire front of the vehicle without requiring multiple separate sensors.
Solution Approach 2:
A single sensing sensor mounted in the bumper performs multiple detection functions by covering four different sensing regions. The sensor can detect crashes from various positions (front, side, angle) and types (pedestrian, object) across the entire front of the vehicle, making one component serve multiple protective roles.
2Reliability
If the sensing sensor is mounted on the bumper, then it can detect pedestrian crashes, but it cannot distinguish between pedestrian crashes and object crashes
Solution Approach 1:
Different sensing regions of the sensor are assigned different detection functions. The first and second sensing regions detect front crashes, while the third and fourth sensing regions detect side crashes. By analyzing which specific region is activated and the characteristics of the impact in that region, the system can distinguish between pedestrian crashes (typically softer, distributed impact) and object crashes (typically harder, concentrated impact).
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 operates the active hood system to reduce impact forces on pedestrians by accurately determining crash positions and types, thereby minimizing damage and enhancing pedestrian protection.
Implementation Method 1
an optical fiber sensor disposed on a front of the rear member and configured to sense an impact force delivered from the bumper at the time of the crash with the pedestrian
Implementation Method 2
a light emitting element disposed on the upper portion of the front of the rear member and configured to emit light while being pressed at the time of the crash with the pedestrian, and a light receiving element disposed on the lower portion of the front of the rear member and configured to absorb the light emitted from the light emitting element to convert the light into electrical energy
Data Source
AI summary
An impact sensor of an active hood system includes a rear member, optical fiber sensors, a front member and membrane switch. Each of the optical fiber sensors is disposed on upper and lower portions of a front of the rear member and senses an impact force delivered from a bumper at the time of a crash with a pedestrian. The front member is disposed at the front of the rear member and has a protrusion part pressing the optical fiber sensors by the impact force delivered from the bumper at the time of the crash with the pedestrian. The membrane switch is disposed between the front member and the optical fiber sensor, divided into a plurality of regions from a left of the front member to a right thereof, and configured to sense a region which is pressed when the pedestrian crashes with the region.