Vehicle Start Control via Engine Torque Feedback
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Solution Overview
Problem
In vehicles equipped with automated manual transmission (AMT) or dual clutch transmission (DCT), it is challenging to perform precise start control due to uncertainties in engine torque and clutch transmission torque, leading to potential rattling, vibration, and compromised drivability.
Innovation Solution
A vehicle start control method that determines the need for engine torque control based on slip amount, engine RPM error, and additional conditions, using proportional and integral components to adjust engine torque, and incorporates feedforward and feedback components for clutch torque control, ensuring stable and smooth vehicle starting.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If only clutch slip control is performed during vehicle start, then the control system remains simple, but engine torque uncertainty causes vibration and rattling
Solution Approach 1:
The patent implements feedback control by continuously monitoring engine RPM deviation from target RPM and adjusting engine torque accordingly. The controller calculates the difference between actual and target engine RPM and uses this feedback signal to modulate engine torque, thereby eliminating vibration and rattling caused by torque uncertainty during clutch engagement.
Solution Approach 2:
The patent dynamically changes engine torque as a control parameter based on real-time engine RPM measurements. By adjusting engine torque magnitude in response to RPM deviations, the system compensates for torque uncertainty and achieves smooth clutch engagement without vibration, transforming a static torque application into a dynamic adaptive process.
2Stability of the object's composition
If engine torque is actively controlled during start, then vehicle starting becomes smoother, but control system complexity increases
Solution Approach 1:
The patent makes the controller perform multiple functions: it manages both clutch slip control and engine torque control, and handles various operating conditions (normal start, TCS activation, HAC activation). By integrating these functions into a single controller that adapts its behavior based on system state, the patent achieves stable vehicle starting without proportionally increasing overall system complexity.
Solution Approach 2:
The patent implements dynamic control where engine torque is continuously adjusted based on real-time engine RPM feedback. The control strategy adapts its behavior depending on the operating condition (normal starting, TCS mode, HAC mode), transforming a static control approach into a dynamic one that maintains stability while managing complexity through conditional logic.
3Adaptability or versatility
If clutch transmission torque varies during engagement, then adaptability to different conditions is improved, but prediction accuracy of required torque deteriorates
Solution Approach 1:
The patent uses feedback control to compensate for the inability to precisely predict clutch transmission torque. By monitoring engine RPM response during clutch engagement and adjusting engine torque in real-time, the system adapts to varying clutch characteristics without requiring accurate prior knowledge of the torque transmission curve, thereby resolving the contradiction between adaptability and prediction accuracy.
Data Source
AI summary
A vehicle start control method includes: a condition determination step of determining, by a controller, whether or not it is necessary to control an engine torque in addition to a slip control of a clutch when a vehicle has started moving; and an engine control step of controlling, by the controller, the engine torque according to an engine error revolutions per minute (RPM) which is a difference between a target engine RPM and an actually measured engine RPM, when it is necessary to control the engine torque in addition to the slip control of the clutch.