Breakable Cross Member Release System for Front Crash Uncoupling
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Solution Overview
Problem
Existing solutions for uncoupling the cross member in a motor vehicle's engine compartment during a front crash either force the powertrain to move backward and deform the passenger compartment or fail to completely uncouple the cross member from other components, leading to increased stress on occupants.
Innovation Solution
A release system that includes breakable connection members and supports designed to automatically break during a crash, allowing the cross member to pivot and slide under the vehicle floor, thereby uncoupling it from the longitudinal members and preventing the powertrain from being dragged with the sub-frame.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Stability of the object's composition
If the powertrain is connected to the sub-frame with breakable connection members that allow the sub-frame to bend and drag the powertrain backward, then the powertrain remains constrained to the sub-frame during deformation, but the powertrain risks hitting and deforming the passenger compartment structure
Solution Approach 1:
The connection system is divided into two independent breakable connection member sets: first connection members connecting the sub-frame to longitudinal members, and second connection members connecting the powertrain to the sub-frame. This segmentation allows the powertrain to be completely separated from the sub-frame during crash, preventing it from being dragged backward and deforming the passenger compartment, while the sub-frame can still deform independently to absorb energy.
Solution Approach 2:
The second connection members connecting the powertrain to the sub-frame are designed to break during crash, effectively extracting/removing the powertrain from the sub-frame constraint. This allows the powertrain to remain stationary relative to the vehicle body while the sub-frame deforms and moves backward, eliminating the harmful effect of powertrain-induced passenger compartment deformation.
2Object-affected harmful factors
If the powertrain is uncoupled from the cross member using supports that automatically break, then the powertrain is released from the cross member, but the cross member remains connected to other body components and continues to transmit stresses to occupants
Solution Approach 1:
The connection system is segmented into multiple breakable connection members: first connection members (connecting sub-frame to longitudinal members) and second connection members (connecting powertrain to sub-frame). This segmentation ensures that both the powertrain and cross member are completely uncoupled from the deforming sub-frame structure, preventing stress transmission to occupants while maintaining a relatively simple overall design.
Solution Approach 2:
The breakable connection members are pre-designed with weakened areas at specific locations to ensure they break at predetermined moments during crash deformation. This preliminary design ensures that the cross member is uncoupled at the optimal time, preventing it from transmitting stresses to occupants while avoiding the need for complex active control systems.
3Object-affected harmful factors
If pyrotechnic devices are used to uncouple the cross member, then the cross member can be released, but the system becomes more complex and expensive
Solution Approach 1:
The breakable connection members are designed with inherent weakened areas that cause them to automatically break when subjected to crash loads, without requiring any external activation systems. The connection members self-destruct through their designed structural weaknesses, eliminating the need for pyrotechnic devices, sensors, or control systems, thereby significantly reducing system complexity and cost while achieving the same protective function.
Solution Approach 2:
The breakable connection members are designed as simple, inexpensive mechanical components with predetermined break points, replacing expensive and complex pyrotechnic release systems. These disposable connection members perform their function once during a crash event and then fail, providing an economical solution that achieves the same safety outcome without the high cost and complexity of pyrotechnic technology.
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 uncouples the cross member from the longitudinal members, allowing the powertrain to move independently and avoid deforming the passenger compartment, reducing stress on occupants and simplifying the design by eliminating the need for pyrotechnic devices.
Implementation Method 1
breakable connection members and supports designed to automatically break during a crash
Data Source
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AI summary
A motor vehicle (1) has a passenger compartment (2) and two longitudinal members (8) provided with respective rear portions (10) arranged longitudinally in the area of the passenger compartment (2) and with respective struts (9), which project forward relative to the passenger compartment (2); the motor vehicle further has a a powertrain (4), which is supported by the cross member (20) and/or by the struts (9), and a cross member (20) with front connection points (24) connected to the longitudinal members (8) so as to be suspended, by means of respective breakable connection members (25), and with rear connection points (30) connected to the aforesaid rear portions (10) by means of connection devices (32) having weakened areas designed so as to break when a given load threshold is exceeded, in order to completely uncouple the cross member (20) from the longitudinal members (8).