Wheel Torque-Based Actuator Control for Smooth Transmission Shifts
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Solution Overview
Problem
Conventional powertrain control systems for vehicles with multiple sources of propulsive power face challenges in managing transmission transitions, leading to inconsistent vehicle acceleration and jerky shifts, particularly in hybrid drivetrain configurations, due to rapid changes in rotational speed and torque requirements during gear shifts.
Innovation Solution
A wheel torque-based powertrain control architecture that determines a compensated TRNAIN torque request, including an inertia compensation component, to manage torque transitions during slipping states of the torque converter and gear shifts, using formulas to estimate torque converter clutch torque based on sub-states and applying low-pass filtering and blending techniques to ensure smooth acceleration.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If conventional powertrain control systems are used with multiple sources of propulsive power, then the system can accommodate hybrid drivetrain configurations, but the rotational speed changes rapidly during transmission shifts causing inconsistent vehicle acceleration and jerky shifts
Solution Approach 1:
The control system determines a compensated TRNAIN torque request that includes an inertia compensation component before the transmission shift occurs. This preliminary torque adjustment accounts for the expected rapid rotational speed changes during the shift, allowing the system to pre-position the torque to maintain smooth vehicle acceleration and prevent jerky shifts.
Solution Approach 2:
The system dynamically adjusts the TRNAIN torque request parameter by adding an inertia compensation component that is calculated based on the torque converter clutch torque estimate. This parameter modification allows the control system to adapt torque delivery during transmission transitions, maintaining acceleration consistency despite rapid rotational speed changes in hybrid drivetrain configurations.
2Stability of the object's composition
If TrnAin torque request is modified during transmission shifts to maintain smooth acceleration, then vehicle acceleration consistency is improved, but the complexity of torque management increases
Solution Approach 1:
The control system introduces a compensated TRNAIN torque request as an intermediary variable that mediates between the driver's torque demand and the actual torque delivery during transmission shifts. This intermediary torque request includes the inertia compensation component and serves as a buffer that simplifies the overall torque management by consolidating multiple control considerations into a single adjusted torque parameter.
3Ease of operation
If inertia compensation component is added to TRNAIN torque request, then jerky shifts are reduced, but the computational requirements and control complexity increase
Solution Approach 1:
The system replaces complex mechanical torque management mechanisms with a computational approach. By calculating the inertia compensation component based on torque converter clutch torque estimates and incorporating it into the TRNAIN torque request, the system achieves smooth shift operation through software-based torque adjustment rather than mechanical complexity.
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 solution ensures consistent and smooth vehicle acceleration during transmission transitions, reducing the perception of jerky shifts and improving fuel economy by decoupling TRNAIN torque from speed and coordinating torque requests across drivetrain actuators.
Implementation Method 1
a torque converter that is disposed in a power path between the source of rotary power and the transmission
Implementation Method 2
determining an estimate of the torque converter clutch torque based in part on the sub-state of the slipping state in which the torque converter is operating
Data Source
AI summary
Systems and control methods can provide for determining a TrnAin torque request from desired vehicle acceleration in a vehicle that utilizes a WTC architecture to allow for smooth transition between different transmission states, such as torque converter bypass clutch states and shifts between transmission gear ratios. The methods provide consistent and smooth vehicle acceleration profile during transmission state transitions. The methods also provide the ability to track the desired vehicle acceleration consistently from virtual driver demand sources, such as adaptive cruise control, autonomous vehicle, or remote parking, without allocating any additional resource to account for transmission state transitions. The proposed methods are applicable to any TC-based automatic transmission drivetrain, such as conventional powertrain, MHT, P4 HEV, or even BEV powertrains where the motor is located on the impeller side of a torque converter.