Torque Converter Locking Control for Powertrain Smoothness
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Power variation during gear shifts in powertrains with torque converters, particularly in heavy machinery, leads to reduced fuel efficiency and rough engine operation, as the engagement or disengagement of the lock-up clutch affects engine speed and throttle control.
Innovation Solution
An electronic controller is used to receive locking and throttle signals, determining the torque converter's state and operating condition to select appropriate load-control power curves, reducing power variation by derating engine power or shifting engine speeds during transitions from converter-drive to direct-drive modes.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of energy
If the torque converter locking mechanism is engaged to improve fuel efficiency, then fuel consumption decreases, but engine roughness and power variation increase during gear shifts
Solution Approach 1:
The electronic controller performs preliminary detection of the torque converter's locking state and throttle position before gear shifts occur. By anticipating the gear shift event and the locking mechanism engagement, the controller pre-adjusts engine power output to prevent power variation and engine roughness during the transition, while still allowing fuel efficiency improvements when the converter is locked.
Solution Approach 2:
The system dynamically adjusts engine power curves based on real-time operating conditions including throttle position, gear ratio, and torque converter locking state. The controller selects different power curves from a library of predetermined curves, enabling the engine to operate smoothly during gear shifts while maintaining fuel efficiency benefits when the converter is locked.
2Object-generated harmful factors
If the locking mechanism is restricted to only a few gear ratio selections to avoid power variation, then engine operation smoothness improves, but overall fuel efficiency decreases
Solution Approach 1:
The system changes the engine operating parameters by selecting from multiple predetermined power curves that are tailored to different operating conditions. Each power curve represents a different combination of engine speed and torque characteristics, allowing the controller to optimize for both smooth operation and fuel efficiency across all gear ratios, not just a limited selection.
Solution Approach 2:
The electronic controller continuously monitors the torque converter's locking state through feedback signals and uses this information to dynamically adjust engine power output. This closed-loop control allows the system to maintain smooth engine operation while exploiting fuel efficiency benefits across all gear ratios by adapting power delivery to the actual locking state.
3Productivity
If the lock-up clutch is engaged for all transmission gear ratios, then direct-drive efficiency improves, but appreciable power variation occurs to the wheels during shifts
Solution Approach 1:
The controller performs preliminary detection of the locking state and throttle position before gear shifts occur. By anticipating the shift event, the controller pre-adjusts engine power output to compensate for the upcoming change in drivetrain characteristics, preventing wheel power variation while maintaining direct-drive efficiency benefits.
Solution Approach 2:
The system changes engine operating parameters by selecting appropriate power curves from a library of predetermined curves tailored to different operating conditions. This allows the engine to deliver power in a manner that compensates for the direct-drive connection, smoothing out power delivery to the wheels during gear shifts while maintaining the efficiency benefits of locked converter operation.
Data Source
AI summary
A machine powertrain includes an engine operably connected to a torque converter and a transmission. A switch associated with the torque converter provides a locking signal indicative of a locked or unlocked condition of the torque converter. A throttle sensor associated with the throttle provides a throttle signal. An electronic controller receives the locking signal and the throttle signal, and controls operation of the engine at least partially based on the throttle signal and the locking signal. The electronic controller determines whether a locked or unlocked condition of the torque converter is present based on the locking signal, determines whether a part throttle operating condition or a full throttle operating condition is present based on the throttle signal, and selects a load-control power curve when the part throttle operating condition is present and when the torque converter switches from the unlocked to the locked condition.