Aftertreatment Catalyst Preheating for Zero NOx Cold-Start Emissions

Solution Overview

Problem

During the warmup period of an engine after a cold start, the aftertreatment system, particularly the SCR system, does not achieve desired NOx reduction due to insufficient catalyst temperature, leading to high NOx emissions.

Innovation Solution

An electric exhaust gas recirculation (EGR) pump is used to generate airflow through an exhaust aftertreatment system heater without starting the engine, heating the catalyst to the required temperature before engine operation, using a reverse airflow direction and leveraging a turbocharger or electric motor to spin the engine without combustion.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Temperature

If the engine is started during cold weather to warm up the aftertreatment system, then the catalyst temperature increases, but NOx emissions increase due to insufficient conversion efficiency

Engineering Contradiction:

Improvecatalyst temperatureVSAvoidNOx emissions

Core Design Contradiction:

TemperatureVSObject-generated harmful factors

Solution Approach 1:

The system performs preliminary heating of the aftertreatment system using a heater element before engine operation. This preliminary action raises the catalyst temperature to the required level (above 200°C) before the engine starts, ensuring that when the engine begins operating, the aftertreatment system is already at optimal temperature for NOx conversion, thereby preventing high emissions during the warmup period

Inventive Principle:

Principle #10Preliminary action

Solution Approach 2:

A heater element is introduced as an intermediary device between the engine and the aftertreatment system. This intermediary provides the necessary thermal energy to the catalyst and aftertreatment components without requiring the engine to run, thus decoupling the heating function from the engine operation and enabling temperature elevation without generating NOx emissions

Inventive Principle:

Principle #24Intermediary (Mediator)

2Object-generated harmful factors

If the engine is kept off during cold weather to prevent NOx emissions, then emissions are reduced, but the aftertreatment system does not reach required temperature

Engineering Contradiction:

ImproveNOx emissionsVSAvoidaftertreatment system temperature

Core Design Contradiction:

Object-generated harmful factorsVSTemperature

Solution Approach 1:

The system performs preliminary heating of the aftertreatment system using a heater element before engine operation. This preliminary action raises the catalyst temperature to the required level (above 200°C) before the engine starts, ensuring that when the engine begins operating, the aftertreatment system is already at optimal temperature for NOx conversion, thereby preventing high emissions during the warmup period

Inventive Principle:

Principle #10Preliminary action

Solution Approach 2:

A heater element is introduced as an intermediary device between the engine and the aftertreatment system. This intermediary provides the necessary thermal energy to the catalyst and aftertreatment components without requiring the engine to run, thus decoupling the heating function from the engine operation and enabling temperature elevation without generating NOx emissions

Inventive Principle:

Principle #24Intermediary (Mediator)

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 method ensures zero NOx emissions during the warmup period by maintaining the aftertreatment system temperature, allowing efficient SCR conversion efficiency upon engine startup.

Implementation Method 1

initiate the heater to increase a temperature of the aftertreatment system

Methodology Applied

Scientific EffectHeating: Heating

Implementation Method 2

control the pump to generate an airflow directed from the intake to the heater to increase the temperature of the aftertreatment system

Methodology Applied

Scientific EffectConvection: Convection

Implementation Method 3

A common component in many of these exhaust aftertreatment systems is a selective catalytic reduction (SCR) system, which reduces a quantity of nitrous oxide (NOx) present in the exhaust gas by injecting a reductant into the flow of exhaust combined with the exhaust gas interacting with a catalyst. The catalyst reacts with the exhaust gas to form nitrogen and water.

Methodology Applied

Scientific EffectCatalysis: Catalysis

Data Source

PatentUS20250334091A1Systems and methods for zero NOX emissions during an operating period

Publication Date: 2025.10.30 CUMMINS INC

AI summary

A system, method, and apparatus for zero or low NOx emissions during a certain operating period are provided. A system can include an aftertreatment system including a catalyst. The system can include a pump coupled to at least an intake of an engine and an exhaust of the engine. The system can include a heater positioned downstream of the engine. The system can further include a controller coupled to at least the aftertreatment system. the pump, and the heater. During a warmup period for the aftertreatment system. the controller is configured to maintain the engine in an off state. initiate the heater to increase a temperature of the aftertreatment system while the engine is in the off state. and control the pump to generate an airflow directed from the intake to the heater to increase the temperature of the aftertreatment system.