Oxidation Catalyst Warming via Exhaust Timing Control

Solution Overview

Problem

The inlet side end face of the oxidation catalyst device in exhaust purification systems can become clogged during low-speed low-load operation due to the adherence of soluble organic fractions and soot, which are highly viscous and easily deposited at low exhaust gas temperatures, affecting regeneration control of the collection filter.

Innovation Solution

An engine control method that adjusts the injection timing and opening-closing timing of valves to raise the exhaust gas temperature before and after supplying unburned fuel to the oxidation catalyst device, warming it until a predetermined period has passed to prevent clogging by drying or combustion-removing adherent substances.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Use of energy by moving object

If the exhaust gas temperature is low during low-speed low-load operation, then fuel economy is improved, but soluble organic fraction and soot adhere to the inlet side end surface of the oxidation catalyst device causing clogging

Engineering Contradiction:

Improvefuel economyVSAvoidclogging of oxidation catalyst device

Core Design Contradiction:

Use of energy by moving objectVSReliability

Solution Approach 1:

The control device performs warming control before supplying unburned fuel to the oxidation catalyst device. By adjusting injection timing and opening-closing timing of the exhaust valve, the exhaust gas temperature is raised above the low temperature threshold, and the oxidation catalyst device is warmed until a predetermined warming period has passed. This preliminary heating action prevents soluble organic fraction and soot from adhering to the inlet side end surface, thereby preventing clogging while maintaining fuel economy during low-speed low-load operation.

Inventive Principle:

Principle #10Preliminary action

2Reliability

If unburned fuel is supplied to the oxidation catalyst device to raise temperature for regeneration, then clogging is prevented, but fuel consumption increases

Engineering Contradiction:

Improveprevention of cloggingVSAvoidfuel consumption

Core Design Contradiction:

ReliabilityVSUse of energy by moving object

Solution Approach 1:

The control device performs warming control before supplying unburned fuel to the oxidation catalyst device. By adjusting injection timing and opening-closing timing of the exhaust valve, the exhaust gas temperature is raised above the low temperature threshold, and the oxidation catalyst device is warmed until a predetermined warming period has passed. This preliminary heating action prevents soluble organic fraction and soot from adhering to the inlet side end surface, thereby preventing clogging while maintaining fuel economy during low-speed low-load operation.

Inventive Principle:

Principle #10Preliminary action

3Reliability

If the exhaust gas temperature is raised by adjusting injection timing and valve timing, then adherence of soluble organic fraction and soot is prevented, but the complexity of control increases

Engineering Contradiction:

Improveprevention of adherenceVSAvoidcontrol system complexity

Core Design Contradiction:

ReliabilityVSDevice complexity

Solution Approach 1:

The control device changes operational parameters including injection timing of the cylinder injection valve, opening-closing timing of the exhaust valve, and the timing of supplying unburned fuel to the oxidation catalyst device. By dynamically adjusting these parameters based on exhaust gas temperature conditions, the system prevents adherence of soluble organic fraction and soot while maintaining manageable control complexity through coordinated parameter modification.

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 prevents adherence of soluble organic fractions and soot to the oxidation catalyst device, reducing clogging and minimizing residual unburned fuel, thereby maintaining system efficiency and preventing fuel consumption deterioration.

Implementation Method 1

an oxidation catalyst device that oxidizes a fuel and a nitrogen oxide contained in the exhaust gas

Methodology Applied

Scientific EffectOxidation: Oxidation

Implementation Method 2

an exhaust gas generated due to combustion of the injected fuel

Methodology Applied

Scientific EffectCombustion: Combustion

Data Source

PatentUS11022057B2Engine and control method therefor

Publication Date: 2021.06.01 ISUZU MOTORS LTD

AI summary

Based on an exhaust gas temperature on an upstream side acquired by an upstream temperature acquisition device, in performing control of supplying an unburned fuel to an oxidation catalyst device in a case where the exhaust gas temperature on the upstream side is lower than a low temperature, a control device performs control of adjusting at least one of an injection timing of a cylinder injection valve and opening-closing timing of an exhaust valve at least one of before and after the supplying control; raising a temperature of the exhaust gas that substantially free of unburned fuel discharged from the exhaust valve to be higher than the low temperature; and warming the oxidation catalyst device until a predetermined warming period has passed.