Hybrid SCR Preheating Using Engine Airflow During Cold Start

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Solution Overview

Problem

Existing aftertreatment systems in vehicles face challenges in effectively reducing nitrogen oxides (NOx) emissions during cold start conditions due to the SCR device's temperature sensitivity, requiring time to reach optimal operating temperatures for efficient NOx conversion, which delays vehicle use and increases emissions.

Innovation Solution

A hybrid powertrain system that uses the electrical drivetrain to fulfill vehicle drive loads while the internal combustion engine generates airflow and heat for the aftertreatment system, allowing the SCR device to be preheated without fueling the engine, thereby accelerating temperature reach and improving NOx reduction efficiency.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Object-generated harmful factors

If the vehicle drive load is kept unfulfilled until the SCR device temperature is within effective range, then NOx emissions are reduced, but vehicle usability is compromised

Engineering Contradiction:

ImproveNOx emissionsVSAvoidvehicle usability

Core Design Contradiction:

Object-generated harmful factorsVSEase of operation

Solution Approach 1:

The system performs preliminary heating of the SCR device using an exhaust heating device before the vehicle drive load is fulfilled. This preliminary action brings the SCR device temperature into the effective range (200°C-280°C) in advance, so that when the vehicle starts, the emissions treatment system is already ready to operate effectively without delaying vehicle usability.

Inventive Principle:

Principle #10Preliminary action

2Temperature

If the internal combustion engine is operated to heat the aftertreatment system during cold start, then SCR device temperature reaches effective range faster, but fuel consumption increases

Engineering Contradiction:

ImproveSCR device temperatureVSAvoidfuel consumption

Core Design Contradiction:

TemperatureVSUse of energy by moving object

Solution Approach 1:

An exhaust heating device is introduced as an intermediary component to heat the aftertreatment system. This intermediary device can be heated by the internal combustion engine and then transfer the heat to the exhaust stream and SCR device, providing a more efficient and controlled heating pathway compared to direct engine operation alone.

Inventive Principle:

Principle #24Intermediary (Mediator)

Solution Approach 2:

The system changes the operational parameters of the internal combustion engine during cold start, operating it without fuel or in a fuel-inefficient mode solely to generate airflow for the exhaust heating device. This parameter change allows the engine to function as an air mover rather than a power source, reducing fuel consumption while still achieving the temperature rise needed for effective SCR operation.

Inventive Principle:

Principle #35Parameter changes

3Productivity

If the internal combustion engine is operated without fuel to generate airflow for heat transport, then SCR device heating efficiency is improved, but engine power output is lost

Engineering Contradiction:

Improveheating efficiencyVSAvoidengine power output

Core Design Contradiction:

ProductivityVSPower

Solution Approach 1:

The internal combustion engine is designed to perform multiple functions: it can operate in fuel-efficient mode to generate airflow for the exhaust heating device during cold start, and then switch to normal power-generating mode once the SCR device is heated. This multi-functionality allows the same component to serve both heating and power generation needs at different times.

Inventive Principle:

Principle #6Universality (Multi-functionality)

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 approach enables efficient NOx reduction at lower temperatures, reducing untreated emissions and allowing vehicle use without delaying startup, thus enhancing emissions treatment and user accessibility.

Implementation Method 1

operating the internal combustion engine to generate airflow for transport of heat through the aftertreatment system

Methodology Applied

Scientific EffectAirflow generation:

Implementation Method 2

directing a heat source to raise a temperature through a selective catalytic reduction (SCR) device of the aftertreatment system

Methodology Applied

Scientific EffectHeat transport: Convection

Implementation Method 3

Selective Catalytic Reduction (SCR) device to treat the exhaust by performing nitrogen oxide (NOx) reduction

Methodology Applied

Scientific EffectCatalytic reduction: Catalysis

Implementation Method 4

nitrogen oxides (NOx) aftertreatment systems are temperature sensitive and there is an optimal amount of heat required for the SCR device to effectively treat the exhaust

Methodology Applied

Scientific EffectNOx conversion:

Data Source

PatentUS11999341B2Aftertreatment heat up strategies in vehicles with hybrid powertrains

Publication Date: 2024.06.04 EATON INTELLIGENT POWER LTD

AI summary

A method of heating an aftertreatment system includes fulfilling a vehicle drive load of a vehicle via an electrical drivetrain of a vehicle hybrid powertrain, wherein the vehicle hybrid powertrain comprises the electrical drivetrain and an internal combustion engine; while the electrical drivetrain is fulfilling the vehicle drive load, operating the internal combustion engine to generate airflow for transport of heat through the aftertreatment system; and directing a heat source to raise a temperature through a selective catalytic reduction (SCR) device of the aftertreatment system.