Gearbox Control Unit Prevents Double Gear Shifts

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Solution Overview

Problem

Conventional automated gearboxes often experience unwanted double gear changes when a driver manually intervenes during an automatic gear change, leading to engine stalling and inefficient fuel consumption.

Innovation Solution

A method and system that prevent unwanted double gear changes by allowing manual gear changes only if the mode selector is activated at least twice during a gear change period, with the first activation barring manual changes and subsequent activations allowing them, thereby mimicking driver control while reducing complexity.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of operation

If manual gear change is allowed during automatic gear change, then driver control over gear selection is improved, but unwanted double gear changes occur causing engine stalling

Engineering Contradiction:
Improvedriver controlVSAvoidgear change stability
Core Design Contradiction:
Ease of operationVSReliability

Solution Approach 1:

The control unit blocks manual gear change requests that are received during an automatic gear change process. By preemptively preventing the manual override during the critical gear transition period, the system avoids the harmful interaction between automatic and manual control signals that would cause double gear changes and engine stalling.

Inventive Principle:
Principle #10Preliminary action

2Reliability

If manual gear change is blocked during automatic gear change, then engine stalling is prevented, but driver's ability to override automatic gear selection is reduced

Engineering Contradiction:
Improvegear change stabilityVSAvoidmanual override capability
Core Design Contradiction:
ReliabilityVSAdaptability or versatility

Solution Approach 1:

The system dynamically adjusts its responsiveness to manual gear change requests based on the current operational state. During automatic gear change, the control unit temporarily disables manual override to ensure stability. Outside this period, full manual control is restored, allowing the system to adapt between safety and driver autonomy based on real-time conditions.

Inventive Principle:
Principle #15Dynamics

3Reliability

If mode selector activation is required twice for manual gear change, then unintended activations are prevented, but system complexity increases

Engineering Contradiction:
Improveintended gear change executionVSAvoidactivation detection logic
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The control unit registers the first activation of the mode selector during automatic gear change and stores this information. When a second activation is detected, the system verifies the stored activation record and then permits the manual gear change. This preliminary recording of the first activation simplifies the logic by using memory rather than complex real-time state machine transitions.

Inventive Principle:
Principle #10Preliminary action

Data Source

PatentEP2478272B1Prevention of unwanted double gear changes for a gearbox
Publication Date: 2014.12.17 SCANIA CV AB
  • EP2478272B1 patent drawingFigure 1~3
  • EP2478272B1 patent drawingFigure 2

AI summary

The present invention relates to a method for prevention of unwanted double gear changes for a gearbox in a motor vehicle which comprises an engine connected to, in order to drive, said gearbox. The gearbox is also adapted to effecting a manual gear change in an automatic mode if a mode selector connected to said gearbox is activated. The method is characterised in that said manual gear change is barred if the mode selector is only activated a first time during a gear change period which represents a period of time during which an automatic gear change is effected in said automatic mode. The present invention relates also to a system, a computer programme, a computer programme product and a motor vehicle which are adapted to preventing an unwanted double gear change.