Hybrid Vehicle Parking Lock Control Device Reducing Noise
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Solution Overview
Problem
Hybrid vehicles experience significant noise and vibration issues when the parking lock is released due to the lack of friction and resistance, leading to prolonged shaking of engine, motor, and transmission units.
Innovation Solution
A control device that sets the lowest shift stage as a preparation shift stage when the parking lock is engaged, using the second shift mechanism to secure a larger inertial mass and reduce noise and vibration upon release, and adjusts the shift stages based on the vehicle's ability to start using the electric motor or internal combustion engine.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If the parking lock mechanism is engaged without setting a preparation shift stage, then the structure remains simple and operation is straightforward, but significant noise and vibration occur when the parking lock is released due to lack of friction and resistance
Solution Approach 1:
The control device sets a preparation shift stage (first or second shift stage) before engaging the parking lock mechanism. This preliminary action ensures that when the parking lock is released, there is already friction and resistance from the engaged shift stage, preventing the parking lock gear and meshing member from shaking excessively. The invention applies preliminary action by preparing the transmission system in advance to mitigate the harmful effects of parking lock release.
2Object-affected harmful factors
If the lowest shift stage is set as preparation shift stage using the second shift mechanism, then a larger inertial mass is secured to reduce noise and vibration, but the device complexity increases due to coordination between multiple shift mechanisms
Solution Approach 1:
The control device sets the lowest shift stage (first or second shift stage) as the preparation shift stage before engaging the parking lock mechanism. This preliminary engagement of a low gear provides maximum inertial mass and friction, effectively reducing noise and vibration when the parking lock is released. The system prepares the transmission in advance to ensure smooth operation upon parking lock release.
Solution Approach 2:
The control device changes the shift stage parameter to the lowest available stage (first or second shift stage) when preparing for parking lock engagement. By selecting the lowest shift stage, the system maximizes the inertial mass and friction characteristics of the transmission, which effectively dampens vibrations and reduces noise during parking lock release. This parameter change optimizes the mechanical properties of the system for the specific operation.
3Reliability
If the control device adjusts shift stages based on vehicle starting capability, then reliability of starting is improved, but the control complexity increases due to multiple decision parameters
Solution Approach 1:
The control device determines whether the vehicle can be started using the electric motor alone and adjusts the preparation shift stage accordingly. This feedback mechanism ensures that the transmission is properly configured based on the actual starting capability, improving reliability. The system monitors vehicle state and makes intelligent decisions about shift stage selection to ensure dependable starting under various conditions.
Solution Approach 2:
The control device dynamically adjusts the preparation shift stage based on real-time vehicle conditions and starting capability. Rather than using a fixed shift stage, the system adapts the transmission configuration according to whether electric motor-only starting is feasible, optimizing both reliability and efficiency for each specific situation.
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
Effectively reduces noise and vibration by securing a larger inertial mass during parking lock release and ensures responsive starting, even when the vehicle cannot be started using the electric motor, by setting the appropriate shift stages and preventing battery depletion.
Implementation Method 1
secure a larger inertial mass and reduce noise and vibration upon release
Data Source
AI summary
Noise and vibration occurring when a parking lock is released can be efficiently reduced in the hybrid vehicle which includes an internal combustion engine and an electric motor serving as the driving sources and a stepped type transmission divided into two systems of a shift shaft at an odd shift stage side and a shift shaft at an even shift stage side. A 2-speed stage is selected as a pre-shift stage set when a meshing member is meshed with a parking lock gear and a parking lock mechanism has a parking lock state. The 2-speed driving gear is joined to an output shaft using a second engagement switching mechanism in a state in which the 2-speed stage is set as the pre-shift stage so that a larger inertial mass can be secured as an inertial mass of a parking lock gear and members joined to an output shaft.