Vehicle Controller Neutral Shift Coast

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Solution Overview

Problem

Existing vehicle coasting control systems prohibit shift operations to neutral, leading to potential overreving or underreving issues when gear shift prohibition fails or when coasting is terminated, as they do not allow power transmission blocking or appropriate gear shifting for changing vehicle speeds.

Innovation Solution

A controller for vehicles that permits shift operation to neutral during coasting control, allowing power transmission blocking after coasting termination and prohibiting gear shifts after neutral transition, while adjusting gear based on vehicle speed to prevent overreving or underreving.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If shift operation to neutral is prohibited during coasting control, then overreving during high-speed travel is prevented, but power transmission cannot be blocked and overreving or underreving may occur when gear shift prohibition fails

Engineering Contradiction:
Improveprevention of overreving during coasting controlVSAvoidability to block power transmission or shift to appropriate gear
Core Design Contradiction:
ReliabilityVSAdaptability or versatility

Solution Approach 1:

The shift operation control is segmented into two distinct phases: during coasting control (where shift to neutral is permitted but shifts to driving gears are prohibited) and after coasting control termination (where shift to neutral is prohibited but shifts to appropriate driving gears are permitted). This segmentation allows the system to address different operational requirements in different phases, resolving the contradiction between preventing overreving and maintaining operational flexibility.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The shift operation prohibition is made dynamic by changing it based on the coasting control state. The electronic control unit dynamically adjusts which gear shifts are prohibited based on whether coasting control is active or has terminated, allowing the system to adapt to changing operational conditions and prevent overreving/underreving at termination while maintaining flexibility during coasting.

Inventive Principle:
Principle #15Dynamics

2Adaptability or versatility

If shift operation to neutral is permitted during coasting control, then power transmission can be blocked after coasting termination, but shift operation to particular gear may cause overreving or underreving at coasting termination

Engineering Contradiction:
Improveability to shift to neutral during coastingVSAvoidprevention of overreving or underreving at coasting termination
Core Design Contradiction:
Adaptability or versatilityVSReliability

Solution Approach 1:

The electronic control unit performs preliminary action by detecting the termination of coasting control and proactively prohibiting shift operations to particular gears before overreving or underreving can occur. This preliminary detection and response prevents the harmful effect from happening in the first place.

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The system uses feedback from the coasting control state detection to control shift operations. When coasting control terminates, the electronic control unit receives feedback about this state change and accordingly prohibits shift operations to particular gears, creating a closed-loop control system that prevents overreving and underreving.

Inventive Principle:
Principle #23Feedback

Data Source

PatentEP3199841B1Controller for vehicle and control method for vehicle
Publication Date: 2020.12.30 TOYOTA JIDOSHA KK
  • EP3199841B1 patent drawingFigure 1
  • EP3199841B1 patent drawingFigure 2
  • EP3199841B1 patent drawingFigure 3

AI summary

An electronic control unit (30; 110) permits a shift operation to a neutral position, by which a manual transmission 14 is switched to neutral, during coasting control. Accordingly, shifting to the neutral position can be performed only by the shift operation. Thus, power transmission can be blocked after termination of the coasting control. In addition, the electronic control unit (30; 110) prohibits the shift operation to a particular gear after the transmission is switched to neutral. Thus, overreving or underreving at the termination of the coasting control can be suppressed.