Automatic Transmission Target State Arbitration During Gear Transitions

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Solution Overview

Problem

Existing methods for controlling kinematic chain state changes in vehicle transmissions fail to efficiently select a new target ratio during transitions, leading to reliability issues and delayed driver acceleration, as they do not effectively manage changes in response to driver requests for acceleration intensity and time constraints.

Innovation Solution

A method that arbitrates between available transmission states based on response time and acceleration intensity criteria, allowing only eligible states to be selected as targets, ensuring compliance with driver demands by assigning priority coefficients and managing transitions to maintain optimal acceleration performance.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If the transmission continues with the initial target state during transition, then the state change can be completed, but the response time to driver acceleration requests increases and acceleration intensity decreases

Engineering Contradiction:
Improvestate change completionVSAvoidacceleration response time
Core Design Contradiction:
ReliabilityVSLoss of time

Solution Approach 1:

The patent applies dynamics by making the target state selection adaptive and changeable during the transition phase. Instead of fixing the initial target state, the system continuously monitors driver acceleration requests and dynamically selects new target states from multiple candidate states to optimize both response time and acceleration intensity while ensuring reliable state change completion.

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The patent changes the parameter of target state selection by introducing multiple candidate states with different gear ratios and characteristics. The system evaluates and selects among these candidates based on current driving conditions, driver requests, and transition progress, thereby optimizing the balance between response time and acceleration performance.

Inventive Principle:
Principle #35Parameter changes

2Productivity

If the transmission selects a new target state during transition to improve acceleration response, then the acceleration intensity increases, but the complexity of state management increases

Engineering Contradiction:
Improveacceleration performanceVSAvoidstate management complexity
Core Design Contradiction:
ProductivityVSDevice complexity

Solution Approach 1:

The patent segments the state management process into distinct phases: identifying candidate target states, evaluating them against multiple criteria (response time, acceleration intensity, reliability), and selecting the optimal state. This segmentation makes the complex decision-making process more manageable and systematic.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The patent performs preliminary actions by pre-identifying and evaluating multiple candidate target states before the transition completes. This allows the system to have ready-made options that can be quickly selected based on current conditions, reducing the complexity of real-time decision-making during active transitions.

Inventive Principle:
Principle #10Preliminary action

3Productivity

If the transmission discards the initial target and selects a new target during transition, then the acceleration response to driver requests improves, but the reliability of the state change process decreases

Engineering Contradiction:
Improveacceleration responseVSAvoidstate change reliability
Core Design Contradiction:
ProductivityVSReliability

Solution Approach 1:

The patent implements feedback by continuously monitoring the transition progress, driver acceleration requests, and vehicle state. This feedback loop allows the system to evaluate whether to maintain the initial target or switch to a new candidate target, making informed decisions that balance acceleration response with state change reliability.

Inventive Principle:
Principle #23Feedback

Solution Approach 2:

The system performs self-service by autonomously evaluating multiple candidate states and selecting the most appropriate target based on predefined criteria and current conditions. This self-contained decision-making process ensures that acceleration requests are responded to efficiently while maintaining reliable state changes without external intervention.

Inventive Principle:
Principle #25Self-service

Data Source

PatentEP3803160B1Method for selecting a target for the state of the drive train of an automatic transmission
Publication Date: 2022.12.14 NISSAN MOTOR CO LTD
  • EP3803160B1 patent drawingFigure 1
  • EP3803160B1 patent drawingFigure 2

AI summary

The invention relates to a method for selecting a target for the state (CRT_GBX_DLS_TGT) of the drive train of an automatic transmission, in a transition phase between a current state and a state initially adopted as a target among many others in order to satisfy an acceleration request of the driver, characterised in that an arbitration between maintaining the initial target and selecting a new target is activated if the change of state between the current state and the initial state is currently being performed in the transmission and if the initial target no longer respects the acceleration requirement of the driver.