Vehicle Launch Control Clutch Torque Rate Limiting
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Solution Overview
Problem
In vehicles with dry clutches, improper control of clutch torque during launch can cause rattling and impact, leading to an unstable and rough vehicle start.
Innovation Solution
A vehicle launch control method that uses a controller to determine target clutch torque through two distinct methods, incorporating feed-forward and feedback components based on accelerator pedal input, with rate limiting to prevent excessive torque variation, ensuring smooth and stable engine synchronization.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Speed
If clutch torque is increased rapidly to accelerate vehicle launch, then launch speed increases, but vehicle rattling and impact occur
Solution Approach 1:
The controller determines target clutch torque in advance based on accelerator pedal manipulation quantity, and applies rate limiting to the increment of target clutch torque. This preliminary control action prevents excessive torque changes that cause rattling and impact, while still achieving smooth vehicle launch.
Solution Approach 2:
The patent dynamically adjusts the increment of target clutch torque based on current operating conditions. The rate limiter adapts the torque increase rate according to engine speed and other parameters, allowing optimal balance between launch performance and comfort throughout the launch process.
2Object-affected harmful factors
If clutch torque is controlled smoothly to prevent rattling, then vehicle launch comfort improves, but launch response time increases
Solution Approach 1:
The patent changes the control parameters dynamically during launch. The target clutch torque increment is adjusted based on engine speed, accelerator pedal position, and other parameters. This allows rapid initial torque application for quick response, then smoother torque increase to prevent rattling as launch progresses.
Solution Approach 2:
The controller continuously monitors engine speed and other parameters during launch, and adjusts the target clutch torque increment accordingly. This feedback mechanism ensures rapid response when needed while preventing excessive torque changes that cause rattling, optimizing both response time and comfort.
3Productivity
If target clutch torque increment is increased to improve launch acceleration, then productivity increases, but engine speed stability deteriorates
Solution Approach 1:
The controller calculates and limits the target clutch torque increment in advance before applying it. This preliminary rate limiting ensures that engine speed remains stable during torque transitions, preventing instability while still allowing sufficient acceleration for productive launch.
4Stability of the object's composition
If rate limiting is applied to target clutch torque increment, then engine speed stability improves, but device complexity increases
Solution Approach 1:
The patent implements rate limiting by changing control parameters based on engine speed and operating conditions. The controller adjusts the maximum allowable torque increment according to current state, providing simple yet effective stability control without complex additional hardware or algorithms.
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 method effectively controls clutch torque to prevent rattling and ensure smooth vehicle launch, improving driving performance and marketability by stabilizing engine speed and torque transitions.
Implementation Method 1
a feed-forward component, based on a target engine speed variation determined according to the manipulated quantity of an accelerator pedal by a driver
Implementation Method 2
a feedback component, based on a target engine speed determined according to the manipulated quantity of the accelerator pedal
Data Source
AI summary
A vehicle launch control method may include judging, by a controller, whether or not a vehicle starts to be launched, determining, by the controller, target clutch torque through a designated first determination method and controlling a clutch based on the determined target clutch torque, upon judging that the vehicle starts to be launched, and determining, by the controller, target clutch torque through a designated second determination method differing from the first determination method and controlling the clutch based on the determined target clutch torque, when an engine speed variation and engine speed jerk respectively satisfy designated variation conditions and jerk conditions during determination of the target clutch torque through the first determination method and control of the clutch based on the determined target clutch torque.