Electrically Heated Catalyst Warm-Up During Engine Idle

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Solution Overview

Problem

Current exhaust aftertreatment systems are not sufficiently operational shortly after the start of a journey, leading to ineffective reduction of exhaust emissions, particularly in compliance with stringent future emission regulations.

Innovation Solution

An electrically heatable catalytic converter is used in conjunction with increasing the internal combustion engine speed to at least 1000 min^-1 during idling, with the catalytic converter being heated via the generator, and a departure restriction is activated to ensure the exhaust gas aftertreatment system is ready before the start of the journey, utilizing a combination of electrical heating and engine speed increase to achieve a sufficient operating state.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Object-generated harmful factors

If the exhaust aftertreatment system is activated before the start of the journey, then exhaust emissions can be effectively reduced, but the energy consumption and complexity of the system increase

Engineering Contradiction:
Improveexhaust emissionsVSAvoidenergy consumption
Core Design Contradiction:
Object-generated harmful factorsVSUse of energy by moving object

Solution Approach 1:

The system performs preliminary heating of the catalytic converter before the journey starts using electrical heating elements integrated into the catalyst structure. This preliminary action ensures the catalyst reaches its light-off temperature before the engine begins operating, enabling immediate emissions reduction without requiring prolonged warm-up during actual driving.

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The patent introduces an intermediary heating system that bridges the gap between cold start conditions and catalyst activation. The electrical heating system acts as a mediator to provide the necessary thermal energy to activate the catalyst before the exhaust gas flow from engine operation becomes sufficient for maintaining catalyst temperature.

Inventive Principle:
Principle #24Intermediary (Mediator)

2Reliability

If the catalytic converter is heated using conventional exhaust gas heating, then the system structure remains simple, but the catalyst activation time is too long to meet stringent emission standards

Engineering Contradiction:
Improveemissions complianceVSAvoidcatalyst activation time
Core Design Contradiction:
ReliabilityVSLoss of time

Solution Approach 1:

The system activates the catalyst before the journey begins through electrical heating, eliminating the warm-up delay that would otherwise occur during initial driving. This preliminary activation ensures the catalyst is ready to reduce emissions immediately when the engine starts operating under load.

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The patent replaces the conventional passive thermal heating method (relying solely on hot exhaust gases) with an active electrical heating system. This substitution allows precise control of heating power and timing, dramatically reducing the time required to reach catalyst activation temperature compared to passive exhaust gas heating alone.

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

3Loss of time

If electrical heating power is increased to heat the catalyst faster, then catalyst activation is achieved, but the load on the generator and energy input increase significantly

Engineering Contradiction:
Improveheating timeVSAvoidgenerator load
Core Design Contradiction:
Loss of timeVSPower

Solution Approach 1:

The electrical heating system operates in periodic cycles rather than continuously, providing high power bursts of heating when needed to raise catalyst temperature, then reducing or stopping when the catalyst approaches activation temperature. This periodic operation reduces average generator load while still achieving rapid catalyst activation.

Inventive Principle:
Principle #19Periodic action

Solution Approach 2:

The system dynamically adjusts the electrical heating power parameter based on the catalyst's temperature state and engine operating conditions. By changing the heating power parameter from high to low as the catalyst warms up, the system achieves rapid activation while minimizing overall energy consumption and generator load.

Inventive Principle:
Principle #35Parameter changes

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 effectively reduces exhaust emissions before and during the journey by ensuring the catalytic converter is adequately heated, maintaining low emissions before starting and efficiently reducing pollutants after the start of driving.

Implementation Method 1

electrical heating of the electrically heatable catalyst

Methodology Applied
Scientific EffectJoule heating: Joule Heating

Data Source

PatentEP4102036B1Method for heating an electrically heated catalyst at idle
Publication Date: 2024.06.05 VOLKSWAGEN AG
  • EP4102036B1 patent drawingFigure 1
  • EP4102036B1 patent drawingFigure 2

AI summary

The invention relates to a method for heating an electrically heated catalyst (105), wherein the method comprises the following steps: electrical heating of the electrically heated catalyst (105) and increasing the speed of the internal combustion engine (10); wherein the steps of the method are carried out while the internal combustion engine is idling and the speed is increased to at least 1000 rpm. The invention further relates to a motor vehicle designed to carry out the method. The combination of electrical heating of the catalyst and increasing the engine speed according to the invention effectively reduces raw emissions shortly after the start of the journey.