Transmission Brake Launch System Torque Control
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Solution Overview
Problem
Conventional vehicle launch methods require drivers to manually manipulate brakes and throttle, which can be unsafe and limited by the foundation brake system's ability to hold the vehicle stationary, restricting torque and performance.
Innovation Solution
A transmission brake launch system that uses a control system to engage and release specific clutches in the transmission, allowing for greater torque transfer than the foundation brake system, enabling improved vehicle staging and launch control by locking the transmission and then releasing it to propel the vehicle.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Force
If the foundation brake system is used to hold the vehicle stationary during launch, then the vehicle can be held in place, but the torque holding capability is limited and restricts performance
Solution Approach 1:
The transmission brake acts as an intermediary device between the engine and the foundation brake system. It provides a dedicated torque reaction path through transmission clutches that can handle higher torque loads than the foundation brakes alone, enabling improved launch performance without overloading the foundation brake system.
Solution Approach 2:
The system replaces reliance on the foundation brake system for torque reaction with a transmission-based brake system. By using transmission clutches to create a mechanical lock that reacts engine torque through the transmission gear set, the system achieves superior torque holding capability compared to foundation brakes alone.
2Force
If the driver manually manipulates brakes and throttle to increase engine power, then available torque is increased, but the driver must simultaneously perform multiple tasks which is difficult to safely or correctly perform
Solution Approach 1:
The control system automatically manages the complex coordination of brake release and throttle application. It monitors vehicle conditions and autonomously controls the transmission brake clutches and engine torque, eliminating the need for the driver to manually coordinate multiple tasks while still achieving optimal launch performance.
Solution Approach 2:
The control system continuously monitors vehicle speed, engine torque, and clutch engagement status to dynamically adjust brake release and torque application. This feedback mechanism ensures safe and correct operation by responding to real-time conditions, replacing the need for manual driver judgment and coordination.
3Force
If additional clutches are added to the transmission to enable the brake launch function, then torque holding capability is improved, but the device complexity increases
Solution Approach 1:
The transmission clutches serve dual functions: their primary role in gear selection and their secondary role as brake launch actuators. By programming the control system to engage specific existing clutches in a predetermined pattern, the system achieves brake launch capability without adding dedicated brake clutches, thus avoiding increased hardware complexity.
Solution Approach 2:
The system merges the brake launch function with the existing transmission clutch architecture. Instead of creating a separate brake system, it combines the torque reaction function with the transmission's existing clutch mechanisms, allowing one set of components to perform multiple functions and reducing overall system complexity.
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 enhances vehicle acceleration by utilizing the transmission's powertrain capabilities to hold the vehicle stationary under greater torque, allowing for faster and more controlled launches with increased engine torque and powertrain inertia.
Implementation Method 1
The plurality of clutches includes only five clutches... actuation of different combinations of a predetermined number of clutches of the plurality of clutches provides powerflow
Data Source
AI summary
A transmission launch system includes a control system and a transmission having a plurality of clutches, where actuation of combinations of a predetermined number of clutches provides powerflow for different transmission drive gears. The control system is configured to initiate a performance launch of the vehicle where the transmission is commanded to engage a combination of the predetermined number of clutches corresponding to a forward drive gear. The transmission is then commanded to engage an additional clutch to lock its output shaft such that engine torque is prevented from being transferred to vehicle drive wheels. The engine generates drive torque greater than a capacity of a vehicle brake system and the control system then commands release of the additional clutch thereby unlocking the output shaft and allowing powerflow in the forward drive gear such that the generated engine drive torque is transferred to the drive wheels to propel the vehicle.