Automatic Transmission Control for Supercharger Temperature Management

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Solution Overview

Problem

Conventional automatic transmission control devices fail to prevent supercharger temperature increases and resulting durability issues when a vehicle is equipped with a supercharger, as they rely on engine load detection and do not account for supercharger temperature, leading to potential overheating and durability deterioration.

Innovation Solution

A control device for an automatic transmission with a manual mode that includes a temperature sensor to detect the supercharger's temperature, a judgment unit to determine if it exceeds a predetermined value, and a gear ratio changeover unit to shift to a higher gear ratio, lowering engine rotation speed and reducing supercharger temperature, even during manual-mode operation.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If the conventional automatic transmission control device relies on engine load detection (throttle opening and engine rotation speed) to determine high-load operation state, then the control logic is simple and easy to implement, but the supercharger temperature cannot be accurately detected leading to inadequate over-revolution prevention when the supercharger is hot

Engineering Contradiction:
Improvesupercharger temperature detection accuracyVSAvoidcontrol device complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The patent introduces intake air temperature as an intermediary parameter to indirectly detect supercharger temperature. Instead of directly measuring supercharger temperature, the system uses the temperature of intake air (which is heated by the supercharger) as a proxy indicator. This intermediary approach enables reliable supercharger temperature detection without requiring direct contact sensors on the supercharger itself, thus improving reliability while maintaining relatively simple device complexity.

Inventive Principle:
Principle #24Intermediary (Mediator)

2Reliability

If the automatic transmission control device performs forcible upshift based on engine load detection, then the over-revolution prevention mechanism is simple, but the supercharger may still overheat and deteriorate in durability when the supercharger is already at high temperature

Engineering Contradiction:
Improvesupercharger durabilityVSAvoidoperation status
Core Design Contradiction:
ReliabilityVSEase of operation

Solution Approach 1:

The patent implements a feedback mechanism where the control device continuously monitors intake air temperature and uses this information to dynamically adjust the upshift determination. When intake air temperature exceeds a predetermined threshold, the system modifies its upshift logic to be more conservative, performing forcible upshifts at lower engine loads to prevent supercharger overheating. This feedback loop ensures supercharger durability by adapting the over-revolution prevention strategy based on real-time thermal conditions.

Inventive Principle:
Principle #23Feedback

Solution Approach 2:

The patent changes the operational parameters for upshift determination based on intake air temperature conditions. When the supercharger is detected to be hot (high intake air temperature), the system adjusts the threshold values and timing parameters for forcible upshift, making the upshift occur earlier or more readily. This parameter adjustment ensures that the transmission protects the supercharger from excessive speeds and temperatures, thereby improving supercharger durability under varying thermal conditions.

Inventive Principle:
Principle #35Parameter changes

Data Source

PatentEP3045780B1A system, a control method and a computer program of an automatic transmission
Publication Date: 2018.05.30 JATCO LTD
  • EP3045780B1 patent drawingFigure 1
  • EP3045780B1 patent drawingFigure 2
  • EP3045780B1 patent drawingFigure 3

AI summary

Provided is a control device of an automatic transmission, by which a supercharger can be prevented from becoming high in temperature and deteriorating in durability. An automatic transmission is connected to an engine (1) in which a supercharger (2) is mounted and has a manual mode to manually select a desired gear ratio from a plurality of fixed gear ratios. A control device includes a manual mode detection unit, a temperature judgment unit (31) and a gear ratio changeover unit (43) arranged such that, when the manual mode detection unit detects that the automatic transmission is in the manual mode and when the temperature judgment unit judges that the temperature of the supercharger is higher than or equal to a predetermined value, the gear ratio changeover unit changes the gear ratio of the automatic transmission to a higher gear ratio and thereby lowers the rotation speed of the engine (1).