Automatic Transmission Shift Control via Active Torque Source Speed Synchronization

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Solution Overview

Problem

Conventional automatic transmission shift control methods suffer from prolonged shifting times and deteriorated shift quality due to passive synchronization of input and output shaft speeds, especially under varying road conditions and in hybrid vehicles without torque converters, leading to compromised drivability and fuel efficiency.

Innovation Solution

A shift control method that actively synchronizes input and output shaft speeds by controlling the torque source's speed, using a controller to determine shift conditions, release and engage elements, and perform speed control based on predefined conditions and slopes to minimize energy loss and improve shifting efficiency.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Loss of time

If passive synchronization by slips is used, then shift quality is maintained under certain conditions, but shifting time is lengthened and shift quality deteriorates under varying running conditions

Engineering Contradiction:

Improveshifting timeVSAvoidshift quality

Core Design Contradiction:

Loss of timeVSReliability

Solution Approach 1:

Instead of passively allowing slips to synchronize speeds, the invention actively controls the torque source speed to achieve synchronization. The controller determines a target speed for the torque source and actively adjusts it to match the required input shaft speed, inverting the traditional passive approach to an active control strategy that reduces shifting time while maintaining quality

Inventive Principle:

Principle #13The other way round (Inversion)

Solution Approach 2:

The invention changes the control parameter from hydraulic pressure alone to torque source speed control. By determining a target speed for the torque source based on current running conditions and actively controlling it, the system adapts to varying conditions (slope, load, temperature) without requiring multiple calibration maps, thus reducing shifting time while maintaining reliable shift quality across all conditions

Inventive Principle:

Principle #35Parameter changes

2Reliability

If multiple calibration maps are prepared for different running conditions, then shift quality is improved for covered conditions, but the number of calibration maps cannot be infinitely increased and conditions not considered still suffer from poor shift quality

Engineering Contradiction:

Improveshift qualityVSAvoidnumber of calibration maps

Core Design Contradiction:

ReliabilityVSDevice complexity

Solution Approach 1:

The invention creates a universal control strategy that works across all running conditions without requiring separate calibration maps for each condition. The controller determines target torque source speed based on current operating parameters (output shaft speed, gear ratio, temperature, load), making the system adaptable to any condition rather than relying on pre-programmed maps for specific scenarios

Inventive Principle:

Principle #6Universality (Multi-functionality)

Solution Approach 2:

The invention transitions from static calibration maps to dynamic speed control. The target speed of the torque source is determined dynamically based on current running conditions including output shaft speed, gear ratio, temperature, and load. This dynamic approach allows the system to adapt to any condition in real-time, eliminating the need for extensive pre-calibration while maintaining high shift quality

Inventive Principle:

Principle #15Dynamics

3Loss of energy

If torque converter is not used in hybrid vehicle, then fuel efficiency is improved, but shift quality deteriorates due to lack of passive speed synchronization

Engineering Contradiction:

Improvefuel efficiencyVSAvoidshift quality

Core Design Contradiction:

Loss of energyVSReliability

Solution Approach 1:

The invention replaces the mechanical speed synchronization function of the torque converter with an electronic control system. The controller determines target speed for the torque source and actively controls it to achieve input shaft speed synchronization, substituting the passive mechanical torque converter function with an active electronic control strategy that maintains shift quality without the energy loss associated with torque converters

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

Data Source

PatentUS9855953B2Shift control method of automatic transmission and shift control apparatus using the method

Publication Date: 2018.01.02 HYUNDAI MOTOR CO LTD

AI summary

A shift control method of an automatic transmission may include determining, by a controller, whether a shift condition is satisfied, beginning, by the controller, release of an off-going element and engagement of an on-coming element when the shift condition is satisfied, determining, by the controller, whether a speed control entry condition is satisfied while performing the release of the off-going element and the engagement of the on-coming element, determining, by the controller, a target speed of a torque source when the speed control entry condition is satisfied, performing, by the controller, speed control of the torque source using the target speed of the torque source, determining, by the controller, whether a speed control completion condition is satisfied while performing the speed control, and completing, by the controller, the release of the off-going element and the engagement of the on-coming element when the speed control completion condition is satisfied.