Manual Gearbox Gear Detection Without Position Sensors

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Solution Overview

Problem

Current methods for determining the engaged gear in a manual gearbox rely on additional sensors, increasing costs, weight, and storage space, and are not effective in situations where the drive train is not closed or when electronically controlled clutches are used.

Innovation Solution

A method that calculates the engaged gear by analyzing the engine's revolution rate over time, its derivative, and vehicle speed using pre-defined characteristic curves, eliminating the need for additional sensors and allowing gear determination even with a partly open drive train.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If additional sensors are used to detect the exact position of the gear lever, then measurement precision of gear position is improved, but device complexity and cost increase

Engineering Contradiction:

Improvegear position detection accuracyVSAvoidsensor system complexity

Core Design Contradiction:

Measurement precisionVSDevice complexity

Solution Approach 1:

The system uses existing sensors (engine revolution rate sensor, vehicle speed sensor) to determine gear position without requiring additional dedicated gear position sensors. The control unit processes data from these existing sensors to infer gear engagement state, making the system self-sufficient using already-available components.

Inventive Principle:

Principle #25Self-service

Solution Approach 2:

The patent replaces mechanical position detection (physical sensors on the gear lever) with a calculation-based approach using engine revolution rate and vehicle speed data. This substitutes mechanical sensing with electronic data processing to achieve the same functional goal.

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

2Measurement precision

If additional sensors are installed for gear detection, then measurement precision is improved, but weight increases

Engineering Contradiction:

Improvegear position detection accuracyVSAvoidvehicle weight

Core Design Contradiction:

Measurement precisionVSWeight of moving object

Solution Approach 1:

Inventive Principle:

Principle #25Self-service

3Measurement precision

If additional sensors are used for gear detection, then measurement precision is improved, but storage space requirements increase

Engineering Contradiction:

Improvegear position detection accuracyVSAvoidstorage space

Core Design Contradiction:

Measurement precisionVSVolume of moving object

Solution Approach 1:

Inventive Principle:

Principle #25Self-service

4Device complexity

If calculation based on engine revolution rate and vehicle speed is used, then device complexity is reduced, but measurement precision deteriorates in certain conditions

Engineering Contradiction:

Improvedetermination system complexityVSAvoidgear determination accuracy

Core Design Contradiction:

Device complexityVSMeasurement precision

Solution Approach 1:

The patent uses characteristic curves that are pre-determined for different gear engagement scenarios. These curves represent the expected relationship between engine revolution rate, its derivative, vehicle speed, and gear position. By comparing real-time measurements against these pre-established patterns, the system achieves accurate gear determination even with a simpler calculation-based approach.

Inventive Principle:

Principle #10Preliminary action

Solution Approach 2:

The system continuously monitors engine revolution rate, calculates its derivative over time, and compares the measured values against characteristic curves for different gears. This feedback mechanism allows the control unit to accurately determine gear position by matching the current operational state with expected patterns for each gear engagement.

Inventive Principle:

Principle #23Feedback

Data Source

PatentUS11231106B2Method for determining the engaged gear in a manual gearbox

Publication Date: 2022.01.25 FORD GLOBAL TECH LLC

AI summary

A method for determining the engaged gear in a manual gearbox of a vehicle comprising a number of gears is described, wherein the vehicle comprises an engine, the manual gearbox, and at least one clutch. The method comprises the following steps: determination of the revolution rate of the engine as a function of time; differentiating the determined revolution rate of the engine against time; determination of the speed of the vehicle; and determination of the engaged gear based on characteristic curves of the revolution rate of the engine as a function of time for a number of the gears in the case of a fixed rate of engagement of the clutch, the revolution rate of the engine, the differential of the revolution rate of the engine against time and the speed of the vehicle.