Power Train Mounting System Roll Displacement Control
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Conventional four-point power train mounting systems are inadequate for supporting high-performance and high-power engines, such as V-6 engines, as they result in increased roll displacement and poor Noise, Vibration, and Harshness (NVH) performance due to low spring constants in roll mounts, leading to amplified vibrations and noise felt by passengers.
Innovation Solution
A power train mounting system with a transversely mounted power train configuration, featuring engine, transmission, front, and rear mounts, where the front and rear mounts are the primary load-bearing components with higher spring constants to support 75-85% of the power train weight, while the engine and transmission mounts, positioned over the principal axis of inertia, support the remaining load and restrict roll displacement, improving NVH performance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Stability of the object's composition
If the spring constant of the roll mount is dramatically raised to restrict roll displacement, then roll displacement is reduced, but NVH performance deteriorates because the roll mounts become ineffective in damping torque-related vibrations from the power train
Solution Approach 1:
The patent divides the load-bearing function among multiple mounts with different characteristics: front and rear mounts (primary load bearing with higher spring constants) and engine/transmission mounts (secondary load bearing with lower spring constants positioned over the principal axis of inertia). This segmentation allows each mount to specialize in specific functions, resolving the contradiction between roll control and vibration damping.
Solution Approach 2:
Different mounts are assigned different spring constants based on their location and function. The front and rear mounts have higher spring constants for load bearing, while the engine and transmission mounts have lower spring constants for vibration damping. This local differentiation of mechanical properties allows simultaneous optimization of roll stability and NVH performance.
2Object-affected harmful factors
If the spring constant of the roll mount is kept low in conventional systems, then NVH performance is maintained, but roll displacement becomes amplified by action-reaction forces from the power train and roll mounts
Solution Approach 1:
The patent segments the mounting system into primary load-bearing mounts (front and rear) and secondary stabilizing mounts (engine and transmission mounts over the principal axis of inertia). This segmentation allows the secondary mounts to control roll displacement without requiring high spring constants, thus maintaining NVH performance while improving roll stability.
3Device complexity
If conventional four-point mounting systems are used for high-power engines, then the system structure is simple, but the system becomes inadequate for supporting heavier engines due to increased roll displacement and poor NVH performance
Solution Approach 1:
The patent enhances the conventional four-point system by repositioning the engine and transmission mounts over the principal axis of inertia and assigning them secondary load-bearing roles. This segmentation of functions among the four mounts improves support capability for heavier engines while maintaining the simplicity of the four-point structure.
Solution Approach 2:
The patent changes the spring constant parameters of different mounts to optimize performance. Front and rear mounts have higher spring constants for load bearing, while engine and transmission mounts have lower spring constants for vibration damping and roll control, enabling the system to support heavier engines effectively.
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 reduces roll displacement and enhances NVH performance by distributing the load and managing vibrations, providing superior ride comfort and noise insulation for both medium- to heavy-weight engines like I-4 and V-6 engines.
Implementation Method 1
the present invention provides installation heights and spring constants of the engine mount and transmission mount such that the front and rear mounts become the primary load bearing mounts
Data Source
AI summary
A power train mounting system includes a front mount, a rear mount, an engine mount, and a transmission mount. Installation heights and spring constants of each mount are predetermined such that the majority of the weight of the power train is supported by the front and rear mounts. Mounting axes of the engine mount, front mount, and rear mount are vertical while the mounting axis of the transmission mount is lateral. The transmission mount may include bridges which vary its spring constant during vehicle roll.