Virtual Launch Torque Control for Smooth ACC Relaunch
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Solution Overview
Problem
Current adaptive cruise control (ACC) systems in heavy-duty vehicles cannot automatically and smoothly relaunch the vehicle from a standstill or low speed, especially in heavy traffic situations.
Innovation Solution
The implementation of an automated virtual launch (AVL-TG) system that generates launch torque requests based on vehicle weight, grade, and engine speed, allowing the vehicle to be launched to a cruise control handover speed without driver input.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Extent of automation
If current ACC systems only modulate vehicle speed while in motion, then the system operation is simple, but the vehicle cannot automatically relaunch from standstill in heavy traffic situations
Solution Approach 1:
The system performs preliminary actions by pre-calculating launch torque demands and preparing powertrain components before actual launch is needed. The controller stores launch torque demand information and prepares the automated manual transmission for smooth engagement, enabling automatic relaunch capability without requiring complex real-time decision-making during the launch moment.
Solution Approach 2:
The patent introduces an intermediary launch torque demand signal that mediates between the ACC system and the automated manual transmission. This intermediate torque demand acts as a bridge, translating ACC speed modulation commands into appropriate torque requests for the transmission, thereby enabling automatic relaunch while maintaining modular system architecture.
2Ease of operation
If automated manual transmission requires closing a clutch to launch, then the transmission control is precise, but the launch process becomes complex and requires multiple input criteria
Solution Approach 1:
The system enables self-service by allowing the automated manual transmission to autonomously manage its own clutch engagement and launch process. The transmission controller receives the launch torque demand signal and independently determines the appropriate clutch engagement strategy, eliminating the need for complex external coordination and multiple input criteria from the driver or other systems.
Solution Approach 2:
The patent applies parameter changes by dynamically adjusting the launch torque demand based on varying operating conditions such as vehicle speed, load, and transmission state. The controller modifies torque demand parameters in real-time to optimize clutch engagement characteristics, enabling smooth automatic launch while simplifying the control interface.
3Reliability
If the vehicle comes to a full stop in heavy traffic, then the vehicle can maintain safe distance, but the vehicle cannot smoothly follow lead traffic without driver intervention
Solution Approach 1:
The system implements feedback by continuously monitoring vehicle speed, position relative to lead traffic, and transmission state. The controller uses this feedback information to determine when launch conditions are met and to adjust the launch torque demand in real-time, ensuring the vehicle maintains safe following distance while automatically relaunching to follow lead traffic smoothly.
Data Source
AI summary
Automated launch torque is provided. An automated virtual launch torque generation (AVL-TG) system may be included in a vehicle, such as a heavy duty truck, that may interoperate with an adaptive cruise control (CC) system to move the vehicle from a standstill or low speed to a CC handover speed. The AVL-TG system may determine a tip-in torque curve configured to mimic a torque curve generated by a human operator's acceleration pedal tip-in from a standstill or low speed. The tip-in torque curve may be represented by torque demand values corresponding to a dynamic pedal saturation level applied over a dynamic pedal rate. The torque demand values determined by the AVL-TG system may mimic an expected or human vehicle operator generated torque request, and may operate to successfully close the clutch and smoothly launch the vehicle from a standstill or low speed.