Drivetrain Control Strategy for Smooth Gear Shifts
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing methods for reducing disturbances in vehicle drive trains during gear changes, such as jerking due to torsional vibrations, face challenges from driveline backlash and compliance, which complicate the design of effective control strategies, especially in vehicles with internal combustion engines and manual transmissions.
Innovation Solution
A control strategy that utilizes torque control, speed control, and position control to synchronize engine and transmission shaft speeds, manage driveline twist, and detect backlash transitions, allowing for smooth powertrain state changes by manipulating engine torque and clutch engagement/disengagement, even with simple electronic clutches.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If torque control is implemented to reduce drivetrain disturbances during gear changes, then vehicle judder is reduced, but control strategy complexity increases due to driveline backlash and compliance
Solution Approach 1:
The control strategy performs preliminary actions by detecting backlash transitions before they complete and preemptively adjusting engine torque to prevent harmful torsional vibrations. The system identifies when the drivetrain is approaching a backlash transition point and modifies torque in advance to ensure smooth gear changes and avoid vehicle judder.
Solution Approach 2:
The system implements feedback control by continuously monitoring drivetrain state, detecting backlash transitions, and adjusting engine torque based on detected conditions. The control unit receives feedback about drivetrain position and torque conditions, then modifies engine torque output to maintain smooth operation and prevent vibrations during gear changes.
2Stability of the object's composition
If engine torque is manipulated to synchronize shaft speeds during gear changes, then transition smoothness is improved, but the risk of uncontrollable drivetrain movement into reverse twist increases
Solution Approach 1:
The control strategy performs preliminary synchronization of shaft speeds before clutch engagement by detecting backlash transitions and adjusting engine torque in advance. This preliminary action ensures that when the clutch engages, the drivetrain is already in a stable state, preventing uncontrollable movement into reverse twist and ensuring reliable powertrain state transitions.
Solution Approach 2:
The control system uses the detected backlash transition as an intermediary signal to coordinate torque manipulation and clutch engagement timing. By using the backlash transition detection as a reference point, the system mediates between engine torque control and clutch actuation to achieve smooth, reliable transitions without causing reverse twist.
3Ease of manufacture
If simple electronic clutches are used instead of complex systems, then cost is reduced, but the ability to precisely control clutch engagement timing is limited
Solution Approach 1:
The system compensates for limited clutch control precision by implementing feedback control through backlash transition detection. The control unit continuously monitors drivetrain state and adjusts engine torque based on detected backlash transitions, effectively replacing the need for highly precise clutch control mechanisms while maintaining smooth engagement timing.
Solution Approach 2:
The invention replaces complex mechanical clutch control systems with an electronic control strategy that manipulates engine torque based on detected backlash transitions. This substitution uses electronic sensing and control to achieve precise engagement timing without requiring complex mechanical clutch actuation systems, reducing overall system complexity while maintaining control precision.
Data Source
Figure 1~2
Figure 3(a)~6
Figure 7~8
AI summary
The invention relates to a method for reducing disturbances in the drivetrain of a motor vehicle with an internal combustion engine and a clutch arranged between an engine output shaft and a transmission input shaft during gear changes, wherein a target value for the speed of the internal combustion engine during a gear change is set to a value based on a predicted input speed of a transmission at the end of the shifting process. While the drivetrain is engaged, torque control (TC) is performed to build up or reduce drivetrain twist, and, if no drivetrain twist is present, speed control (SC) is performed to synchronize the speeds of the engine output shaft (2) and the transmission output shaft (7), as well as position control (PC) to hold the drivetrain in a dead-gear state (IL).