Upshift Delay Mechanism for Fuel Cut Acquisition

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Solution Overview

Problem

Existing motor vehicle upshift management systems fail to optimize fuel efficiency by prematurely shifting gears during sudden pedal releases, leading to increased viscous losses and reduced fuel economy.

Innovation Solution

Implementing an upshift delay mechanism that activates a lockup clutch and prevents fuel from entering the engine when a sudden pedal release is detected, maintaining the current transmission mode indefinitely until the throttle is open, and engaging decel lockup control to utilize vehicle momentum and conserve fuel.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Loss of energy

If an upshift is performed during sudden pedal release, then the transmission shifts to a higher gear, but viscous losses increase and fuel economy deteriorates

Engineering Contradiction:

Improveviscous lossesVSAvoidfuel economy

Core Design Contradiction:

Loss of energyVSProductivity

Solution Approach 1:

The system performs preliminary detection of sudden pedal release conditions and pre-activates the lockup clutch before the upshift occurs. This preliminary action ensures the transmission is in lockup mode during the upshift, preventing viscous losses from occurring during the gear transition, thereby resolving the contradiction between maintaining smooth shifts and reducing energy loss.

Inventive Principle:

Principle #10Preliminary action

2Productivity

If the lockup clutch is engaged during upshift, then fuel cut time is extended and fuel economy improves, but engine stall may occur if engine speed falls below fuel recovery speed

Engineering Contradiction:

Improvefuel economyVSAvoidengine stall prevention

Core Design Contradiction:

ProductivityVSReliability

Solution Approach 1:

The system continuously monitors engine speed and compares it against the fuel recovery speed threshold. When engine speed approaches the critical threshold during lockup clutch engagement, the control system provides feedback to adjust the upshift timing or duration, preventing engine stall while maximizing fuel cut benefits. This feedback mechanism resolves the contradiction between extending fuel cut for economy and maintaining reliability.

Inventive Principle:

Principle #23Feedback

3Loss of energy

If upshift delay is implemented during sudden pedal release, then fuel efficiency is enhanced, but the system complexity increases

Engineering Contradiction:

Improvefuel efficiencyVSAvoidsystem complexity

Core Design Contradiction:

Loss of energyVSDevice complexity

Solution Approach 1:

The control system automatically detects sudden pedal release conditions using existing sensor data and autonomously determines when to activate the lockup clutch and delay upshift. The system serves itself by utilizing already-available throttle position and transmission mode information, eliminating the need for additional complex hardware or manual intervention, thus achieving fuel efficiency improvement without proportionally increasing system complexity.

Inventive Principle:

Principle #25Self-service

Data Source

PatentUS8352133B2Upshift delay for fuel cut acquisition

Publication Date: 2013.01.08 HONDA MOTOR CO LTD

AI summary

A system and method for upshift delay for fuel cut acquisition is disclosed. Decel lockup control may be activated if a lift foot upshift is prevented after sudden pedal release. Fuel economy may be increased by cutting fuel to the engine when decel lockup control is engaged. When the throttle is reapplied, the regular shift map resumes control and performs an upshift if necessary.