Automatic Transmission Torque Control for Upthrust Shock Suppression

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Solution Overview

Problem

Conventional automatic transmission systems experience upthrust shock due to a sudden rise in engine torque during auto-upshift from first gear to second gear, which compromises acceleration performance.

Innovation Solution

The upper limit torque is gradually raised from the low gear upper limit torque to a higher high gear upper limit torque during the inertia phase of auto-upshift, using a prescribed gradient, to smooth the transition and prevent shock.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Power

If the second gear upper limit torque is set higher than the first gear upper limit torque, then acceleration performance is improved, but upthrust shock occurs due to sudden torque rise during auto-upshift

Engineering Contradiction:

Improveacceleration performanceVSAvoidupthrust shock

Core Design Contradiction:

PowerVSObject-affected harmful factors

Solution Approach 1:

The upper limit torque is dynamically adjusted during the inertia phase of auto-upshift, transitioning from the first gear upper limit torque to the second gear upper limit torque according to shift progress degree, rather than maintaining a fixed torque value

Inventive Principle:

Principle #15Dynamics

Solution Approach 2:

The upper limit torque parameter is changed gradually during the inertia phase based on the shift progress degree, transforming the torque from the first gear level to the second gear level in a controlled manner to prevent sudden torque rises

Inventive Principle:

Principle #35Parameter changes

2Object-affected harmful factors

If the upper limit torque is raised gradually during the inertia phase, then upthrust shock is suppressed, but acceleration performance may be compromised

Engineering Contradiction:

Improveupthrust shock suppressionVSAvoidacceleration performance

Core Design Contradiction:

Object-affected harmful factorsVSPower

Solution Approach 1:

The upper limit torque is preliminarily adjusted during the inertia phase before the upshift is completed, preparing the torque transition in advance to ensure smooth connection to the second gear upper limit torque without compromising acceleration

Inventive Principle:

Principle #10Preliminary action

Solution Approach 2:

The torque transition is maintained continuously during the entire inertia phase, ensuring uninterrupted and smooth torque delivery from first gear to second gear, preventing both shock and performance loss

Inventive Principle:

Principle #20Continuity of useful action

Data Source

PatentUS11110930B2Control device for automatic transmission

Publication Date: 2021.09.07 JATCO LTD

AI summary

A control device for an automatic transmission includes a traveling drive source, an automatic transmission, an AT controller, and a traveling drive source controller. The AT controller is configured to execute shifting by changeover of friction elements upon receiving a shift request. The traveling drive source controller is configured to execute torque limit control of the traveling drive source when a request for limiting a torque by an upper limit torque is input from the AT controller. The AT controller has an upper limit torque change processing unit configured to change the upper limit torque from a low gear upper limit torque to a high gear upper limit torque when auto-upshift is executed. The upper limit torque change processing unit is configured to raise the upper limit torque using a prescribed gradient during an inertia phase when the inertia phase is started with the auto-upshift.