EGR Pipe Canning for ATS Thermal Insulation

Resolve Bottlenecks,
Find Innovative SolutionsGenerate Solutions

Solution Overview

Problem

Existing EGR systems in internal combustion engines, particularly in heavy-duty vehicles, face inefficiencies in NOx reduction during engine warm-up due to the inability of after-treatment systems (ATS) to convert NOx at lower temperatures, necessitating increased low-pressure EGR usage which can lead to heat dispersion and reduced effectiveness.

Innovation Solution

The EGR system integrates an ATS component with a canning structure that creates a chamber for recirculating exhaust gas countercurrently around ATS components like SCR, DPF, and DOC, enhancing thermal insulation and potentially reducing the need for an EGR cooler by utilizing exhaust gas heat for insulation and refreshing the gas flow.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Object-generated harmful factors

If low-pressure EGR is used to reduce NOx during engine warm-up, then NOx production is limited, but heat dispersion occurs and EGR effectiveness is reduced

Engineering Contradiction:

ImproveNOx productionVSAvoidheat dispersion

Core Design Contradiction:

Object-generated harmful factorsVSLoss of energy

Solution Approach 1:

The invention converts the harmful heat dispersion in low-pressure EGR systems into a beneficial thermal insulation effect. The EGR conduit is designed to surround the ATS component (DOC, DPF, or SCR), creating a thermal insulation barrier that prevents heat loss to the environment. The exhaust gas flowing through the EGR conduit acts as a thermal insulator, converting the previously harmful heat dispersion into a useful thermal protection mechanism for the ATS components.

Inventive Principle:

Principle #22Blessing in disguise (Convert harm into benefit)

Solution Approach 2:

The invention implements a nested structure where the EGR conduit is arranged coaxially around the ATS component. The EGR conduit forms an annular passage that surrounds the catalyst housing, creating a nested configuration similar to nested dolls. This allows the EGR gas flow to occur in concentric layers around the ATS component, maximizing thermal insulation while maintaining compact space utilization.

Inventive Principle:

Principle #7Nested doll (Nesting)

2Object-generated harmful factors

If ATS components are used to convert NOx, then NOx reduction efficiency improves, but the system requires high operational temperature (light off temperature around 250°C) which is not achieved during engine warm-up

Engineering Contradiction:

ImproveNOx conversion efficiencyVSAvoidATS operational temperature

Core Design Contradiction:

Object-generated harmful factorsVSTemperature

Solution Approach 1:

The invention addresses the temperature requirement issue by converting the thermal energy that would otherwise be lost during engine warm-up into a useful heating source for the ATS components. The EGR conduit surrounding the ATS component captures and retains thermal energy, preventing heat dispersion to the environment. This ensures that the ATS components reach and maintain their light-off temperature (around 250°C) more quickly during engine warm-up, enabling effective NOx conversion even when the engine is not fully warmed up.

Inventive Principle:

Principle #22Blessing in disguise (Convert harm into benefit)

3Object-generated harmful factors

If EGR gas is withdrawn downstream of the turbine (low-pressure EGR), then NOx production is limited, but the EGR system loses thermal energy to the environment

Engineering Contradiction:

ImproveNOx productionVSAvoidthermal energy loss

Core Design Contradiction:

Object-generated harmful factorsVSLoss of energy

Solution Approach 1:

The invention transforms the previously harmful thermal energy loss in low-pressure EGR systems into a beneficial insulation mechanism. By arranging the EGR conduit to surround the ATS component, the hot EGR gas flowing through the conduit creates a thermal barrier that prevents heat loss from the ATS component to the environment. The thermal energy that would have been wasted is now retained and used to maintain ATS component temperature, improving overall system efficiency.

Inventive Principle:

Principle #22Blessing in disguise (Convert harm into benefit)

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 improves the thermal management of ATS components, enhances their efficiency, and aids in reaching operational temperatures faster, thereby optimizing NOx reduction and engine warm-up processes.

Implementation Method 1

a portion of the exhaust gas, after having crossed said first ATS component is recirculated through a conduit which partially surrounds the same first ATS component by increasing its thermal insulation from the ambient air

Methodology Applied

Scientific EffectThermal insulation: Thermal Insulation

Implementation Method 2

the thermal content of said portion of said exhaust gas is exploited to insulate said first ATS component and, on the other side, such portion of the exhaust gas is refreshed

Methodology Applied

Scientific EffectHeat transfer: Convection

Data Source

PatentEP3406874B1EGR layout of an internal combustion engine comprising an after treatment system

Publication Date: 2020.02.19 FPT MOTORENFORSCHUNG AG

Figure 1~2
Figure 3

AI summary

EGR layout of an internal combustion engine comprising an after treatment system (ATS), the ATS comprising at least one first component (DOC, DPF, SCR) suitable to reduce/eliminate pollutants contained in exhaust gas of said combustion engine, the EGR layout comprising an EGR pipe (EGRP) suitable to connect a point of an exhaust line (EP) with a point of an inlet line (IP) of said internal combustion engine, wherein, the EGR pipe is shaped as a canning (CN) defining a chamber (CH) enveloping said at least one first ATS component.