Motorcycle Exhaust Lambda Sensor Placement for Emission Validation

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Solution Overview

Problem

Current exhaust gas cleaning systems for single-track vehicles, such as motorcycles, are inadequate for meeting future emission standards like EU 5, as they lack validation of exhaust gas cleaning quality and are not efficiently designed for these vehicles.

Innovation Solution

Placing two lambda sensors in the exhaust gas flow of internal combustion engines, with the first sensor close to the cylinder head and the second sensor behind the catalytic converter, to effectively measure and validate the exhaust gas cleaning process, optimizing space usage and improving measurement accuracy.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Speed

If a single lambda sensor is placed upstream of the catalytic converter, then the control frequency is improved, but the validation of exhaust gas cleaning quality is lost

Engineering Contradiction:
Improvecontrol frequencyVSAvoidexhaust gas cleaning validation
Core Design Contradiction:
SpeedVSMeasurement precision

Solution Approach 1:

The exhaust gas measurement function is segmented into two distinct tasks performed by two separate lambda sensors: one sensor upstream of the catalytic converter for control purposes, and another sensor downstream for validation of cleaning quality. This segmentation allows both control frequency and cleaning validation to be achieved simultaneously without compromise.

Inventive Principle:
Principle #1Segmentation

2Measurement precision

If the first lambda probe is placed close to the cylinder head, then the measurement accuracy is improved, but the installation space requirements increase

Engineering Contradiction:
Improveexhaust gas measurement accuracyVSAvoidinstallation space
Core Design Contradiction:
Measurement precisionVSVolume of moving object

Solution Approach 1:

The patent utilizes the vertical dimension and available space in the non-visible area of the motorcycle exhaust system. By routing exhaust system components with vertical flow (catalytic converters and silencers) between the rear wheel and swingarm, the design creates three-dimensional space utilization that accommodates the close placement of the first lambda probe near the cylinder head while maintaining compact overall packaging.

Inventive Principle:
Principle #17Another dimension (Dimensionality change)

3Volume of moving object

If the second lambda probe is placed close to the catalytic converter, then the space usage is optimized, but the measurement of cleaned exhaust gas flow is compromised

Engineering Contradiction:
Improveinstallation spaceVSAvoidcleaned exhaust gas measurement
Core Design Contradiction:
Volume of moving objectVSMeasurement precision

Solution Approach 1:

The patent employs asymmetric positioning of the second lambda probe at a specific distance (maximum four times the diameter of the catalytic converter) downstream from the catalytic converter. This asymmetric placement optimizes the balance between space utilization and measurement accuracy by positioning the sensor in a location where the exhaust gas flow has stabilized enough for accurate measurement while still maintaining compact packaging suitable for motorcycle applications.

Inventive Principle:
Principle #4Asymmetry

Applied Scientific Principles

This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.

Function Achieved in This Case

This configuration enhances exhaust gas measurement, ensures more environmentally friendly operation, and meets future emission standards by validating the quality of exhaust gas cleaning, while efficiently utilizing available installation space.

Implementation Method 1

sensors are used to measure the oxygen concentration in the exhaust gas

Methodology Applied
Scientific EffectOxygen concentration measurement:

Implementation Method 2

the internal combustion engine has a catalytic converter

Methodology Applied
Scientific EffectCatalytic conversion: Catalysis

Data Source

PatentEP3655634B1Exhaust gas system for an internal combustion engine
Publication Date: 2023.05.03 BAYERISCHE MOTOREN WERKE AG
  • EP3655634B1 patent drawingFigure 1

AI summary

The invention relates to an exhaust gas system for an internal combustion engine of a single-track vehicle, wherein the exhaust gas system can be arranged on an exhaust gas outlet of a cylinder head of the internal combustion engine and wherein a first lambda probe close to the cylinder head is provided in the exhaust gas system and is arranged before an exhaust gas cleaning system in the flow direction of an exhaust gas, wherein a second lambda probe is provided in the exhaust gas system after the exhaust gas cleaning system in the flow direction of the exhaust gas, wherein the second lambda probe is arranged at a maximum distance away from the exhaust gas cleaning system equal to four times the diameter of the exhaust gas cleaning system. As a result of the design of the exhaust gas system for an internal combustion engine of a single-track vehicle according to the invention, the lambda probe is arranged in the non-visible region of the single-track vehicle, while simultaneously examining the quality of the exhaust gas cleaning.