Exhaust Purification Device Temperature Control

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Solution Overview

Problem

The challenge is to prevent an excessive temperature rise in the exhaust gas purification device when regenerating it, especially when liquid fuel and compressed natural gas are mixed and combusted, as methane from CNG has low ignitability, leading to increased hydrocarbon (HC) emissions and potential overheating.

Innovation Solution

An HC supply amount control device is implemented to decrease the amount of HC supplied to the exhaust gas purification device when liquid fuel and CNG are combusted, calculating the difference in HC emissions between pure liquid fuel and mixed combustion scenarios to regulate the HC supply, thereby preventing excessive temperature rises and reducing unoxidized HC release.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If HC is supplied to the exhaust gas purification device to raise its temperature for regeneration, then the purification device can be regenerated, but the temperature may rise excessively when liquid fuel and CNG are mixed and combusted

Engineering Contradiction:
Improveregeneration of exhaust gas purification deviceVSAvoidtemperature of exhaust gas purification device
Core Design Contradiction:
ReliabilityVSTemperature

Solution Approach 1:

The HC supply amount is dynamically adjusted based on the combustion mode. When liquid fuel and CNG are mixed and combusted, the HC supply amount is decreased compared to when only liquid fuel is combusted. This dynamic adjustment prevents excessive temperature rise while ensuring sufficient regeneration in different operating conditions.

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The supply amount parameter of HC is changed according to the combustion mode. The control device decreases the HC supply amount when liquid fuel and CNG are mixed and combusted, thereby controlling the temperature parameter of the exhaust gas purification device to prevent excessive temperature rise during regeneration.

Inventive Principle:
Principle #35Parameter changes

2Temperature

If the HC supply amount is decreased to prevent excessive temperature rise, then temperature control is improved, but the regeneration effectiveness may be insufficient

Engineering Contradiction:
Improvetemperature of exhaust gas purification deviceVSAvoidregeneration effectiveness
Core Design Contradiction:
TemperatureVSReliability

Solution Approach 1:

The control device determines the combustion mode and adjusts the HC supply amount accordingly. This feedback mechanism ensures that the HC supply amount is optimized for each combustion mode, achieving both temperature control and sufficient regeneration effectiveness without excessive temperature rise.

Inventive Principle:
Principle #23Feedback

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 effectively suppresses excessive temperature increases in the exhaust gas purification device during regeneration, ensuring sufficient regeneration while minimizing HC release to the outside, thus maintaining optimal operating conditions.

Implementation Method 1

an exhaust gas purification device that is arranged in an exhaust passage of the internal combustion engine and has an oxidation function

Methodology Applied
Scientific EffectOxidation: Oxidation

Implementation Method 2

the temperature of the exhaust gas purification device will go up due to the heat of oxidation or combustion generated by the oxidation of this HC

Methodology Applied
Scientific EffectHeat of oxidation or combustion: Exothermic Reaction

Data Source

PatentEP2650498B1Exhaust gas purification system for an internal combustion engine
Publication Date: 2020.05.13 TOYOTA JIDOSHA KK
  • EP2650498B1 patent drawingFigure 1
  • EP2650498B1 patent drawingFigure 2
  • EP2650498B1 patent drawingFigure 3

AI summary

The present invention is intended to suppress, in an exhaust gas purification system for an internal combustion engine capable of mixing and combusting liquid fuel and compressed natural gas, an excessive rise in temperature of an exhaust gas purification device at the time when the exhaust gas purification device is caused to regenerate. In the exhaust gas purification system for an internal combustion engine according to the present invention, when the liquid fuel and the compressed natural gas are caused to mix and combust in the internal combustion engine at the time of regenerating the exhaust gas purification device, an amount of HC to be supplied to the exhaust gas purification device from an HC supply device is decreased in comparison with the time when only the liquid fuel is caused to combust in the internal combustion engine.