Insulating Heater Ring for Soot Combustion in Electrically Heated Catalyst

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Solution Overview

Problem

Conventional electrically heated exhaust gas control devices fail to address the issue of soot accumulation, which can lead to short-circuiting and heat generation failures due to the conductive nature of soot in exhaust gases, especially during cold engine starts in hybrid vehicles.

Innovation Solution

An electrically heated catalytic device with a heater ring made of insulating material, positioned upstream of the energization-exothermic substrate, combusting soot deposits and preventing short-circuiting by using the energization-exothermic substrate as a heat source, along with an insulating mat and dense portions for enhanced heating efficiency and durability.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Temperature

If an energization-exothermic honeycomb carrier is used to generate heat for heating the catalyst, then the catalyst can be heated quickly even in cold conditions, but soot accumulation on the carrier causes short-circuiting and heat generation failure

Engineering Contradiction:

Improvecatalyst temperatureVSAvoidheat generation reliability

Core Design Contradiction:

TemperatureVSReliability

Solution Approach 1:

The device is divided into two separate functional components: an insulating honeycomb carrier for heat generation and a metal catalyst carrier for catalytic activity. This segmentation prevents soot accumulation on the energization-exothermic carrier from causing short-circuiting, while still enabling effective heat transfer to the catalyst.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

An insulating honeycomb carrier acts as an intermediary between the heating mechanism and the catalyst. It transfers heat to the catalyst while its insulating properties prevent soot-induced short-circuiting, thereby maintaining reliable heat generation even in the presence of soot accumulation.

Inventive Principle:

Principle #24Intermediary (Mediator)

2Use of energy by moving object

If the engine is stopped frequently during EV running in hybrid vehicles, then energy consumption is reduced, but the exhaust system remains cold and catalyst activity is low

Engineering Contradiction:

Improveenergy consumptionVSAvoidexhaust system temperature

Core Design Contradiction:

Use of energy by moving objectVSTemperature

Solution Approach 1:

The energization-exothermic honeycomb carrier is activated in advance to preheat the catalyst before cold exhaust gas arrives. This preliminary heating action ensures the catalyst reaches its operating temperature quickly, maintaining catalytic activity even when the engine is stopped frequently during EV running.

Inventive Principle:

Principle #10Preliminary action

Solution Approach 2:

The heating mechanism operates periodically to maintain catalyst temperature during intermittent engine operation. By providing periodic heat activation, the system ensures the catalyst remains active despite frequent stop-start cycles associated with hybrid vehicle EV running modes.

Inventive Principle:

Principle #19Periodic action

3Device complexity

If soot is allowed to accumulate on the energization-exothermic carrier, then the device structure is simplified, but short-circuiting occurs and heat generation fails

Engineering Contradiction:

Improvedevice structureVSAvoidheat generation reliability

Core Design Contradiction:

Device complexityVSReliability

Solution Approach 1:

The insulating properties of the honeycomb carrier material are utilized to convert the potential harm of soot accumulation into a beneficial feature. The insulating carrier prevents soot-induced short-circuiting, transforming what would be a harmful accumulation into a non-problematic condition that does not compromise heat generation reliability.

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

Effectively removes soot deposits through combustion, preventing short-circuiting and maintaining device performance and durability, while reducing power consumption by optimizing heat transfer and storage properties.

Implementation Method 1

an energization-exothermic substrate (a catalytic carrier) that is formed of a material generating heat through energization

Methodology Applied

Scientific EffectJoule heating: Joule Heating

Implementation Method 2

a soot combustion removal portion that removes through combustion soot in exhaust gas, which is deposited on the heater ring, by heat of the heater ring

Methodology Applied

Scientific EffectCombustion: Combustion

Implementation Method 3

When the substrate generates heat through energization, the heater ring is heated through the transfer of the heat to the heater ring

Methodology Applied

Scientific EffectHeat transfer: Conduction (thermal)

Data Source

PatentUS8701394B2Electrically heated catalytic device and vehicle equipped with electrically heated catalytic device

Publication Date: 2014.04.22 TOYOTA JIDOSHA KK

AI summary

An electrically heated catalytic device includes an electrically heated catalyst accommodated in an outer casing provided on an exhaust pipe. A heater ring made of an insulating material is provided adjacent to an outer peripheral edge portion of an upstream end face of the electrically heated catalyst. The heat of the electrically heated catalyst is transferred to the heater ring by generating resistive heat in the electrically heated catalyst. When the soot in exhaust gas accumulates on the surface of the heater ring, the deposits of soot is removed through combustion by the heat from the surface of the heater ring.