Cold-Start Exhaust Filtration With Ozone Soot Oxidation

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Solution Overview

Problem

Internal combustion engines emit significant soot particles during cold-start conditions due to insufficient fuel evaporation at low coolant temperatures, leading to incomplete filtration by the particulate filter, which increases particulate emissions.

Innovation Solution

A bypass filtration system with a ozone generator is introduced to divert exhaust during cold starts, using a bypass particulate filter and ozone injection to oxidize soot particles, enhancing filtration efficiency and regenerating the filter.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If the exhaust is passed through the particulate filter during cold start, then some filtration is achieved, but the filtration efficiency is partial and insufficient

Engineering Contradiction:

Improveparticulate emissions reductionVSAvoidfiltration efficiency

Core Design Contradiction:

ReliabilityVSProductivity

Solution Approach 1:

The exhaust filtration system is divided into two separate paths: the main path through the particulate filter for normal operation, and a bypass path with a second particulate filter for cold start conditions. This segmentation allows each filter to be optimized for its specific function, with the bypass filter providing enhanced filtration capability when needed most during cold starts.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The system changes the filtration parameters by introducing a second particulate filter in parallel during cold start conditions. This parameter change enables the system to achieve higher filtration efficiency (reducing particulate emissions by up to 90%) when the engine is cold, while maintaining normal operation through the primary filter during warm-up.

Inventive Principle:

Principle #35Parameter changes

2Reliability

If the bypass filtration system is used during cold start, then particulate emissions are reduced by up to 90%, but the device complexity increases

Engineering Contradiction:

Improveparticulate emissions reductionVSAvoidexhaust system structure

Core Design Contradiction:

ReliabilityVSDevice complexity

Solution Approach 1:

The exhaust system is segmented into multiple filters with selective activation. The bypass filter is only activated during cold start conditions, allowing the system to achieve high emissions reduction (up to 90%) when needed while avoiding the complexity of having two always-active filters. The control system selectively opens/closes the bypass path based on engine temperature.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The system dynamically adjusts the filtration path based on engine operating conditions. During cold start, the bypass filter is activated to provide enhanced filtration. During normal operation, the primary filter handles the exhaust flow. This dynamic configuration allows the system to achieve high emissions reduction during cold starts without permanently increasing device complexity.

Inventive Principle:

Principle #15Dynamics

3Reliability

If ozone is injected to oxidize soot particles, then filtration effectiveness is maintained and backpressure is reduced, but energy consumption increases

Engineering Contradiction:

Improvefilter effectivenessVSAvoidozone generation energy

Core Design Contradiction:

ReliabilityVSUse of energy by moving object

Solution Approach 1:

The system uses ozone to oxidize soot particles captured by the bypass filter, converting the harmful soot into less harmful oxidation products. This process maintains filter effectiveness and reduces backpressure by removing accumulated particulate matter. The ozone generator provides the necessary oxidative capability to regenerate the filter during cold start conditions.

Inventive Principle:

Principle #22Blessing in disguise (Convert harm into benefit)

Solution Approach 2:

The system employs ozone as a strong oxidant to accelerate the oxidation of soot particles in the bypass filter. This accelerated oxidation process efficiently removes particulate matter from the filter during cold start, maintaining filter effectiveness and reducing backpressure. The ozone generator provides the concentrated oxidizing agent needed for rapid soot combustion.

Inventive Principle:

Principle #38Strong oxidants (Accelerated oxidation)

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

The system effectively reduces cold-start particulate emissions by up to 90% through oxidative conversion of soot to CO2 and CO, maintaining filter effectiveness and reducing backpressure.

Implementation Method 1

oxidative conversion of soot to CO2 and CO

Methodology Applied

Scientific EffectOxidation: Oxidation

Data Source

PatentUS12421881B2System and method for reducing internal combustion engine emissions

Publication Date: 2025.09.23 SAUDI ARABIAN OIL CO

AI summary

A system for reducing internal combustion engine emissions. The system includes an exhaust line for feeding an exhaust from an internal combustion engine to a catalytic converter and a particulate filter to produce a filtered exhaust. The system further includes a filter effluent line to feed this filtered exhaust to a tailpipe. The system further includes a bypass filtration system to receive the filtered exhaust and further filter the exhaust and return it to the filter effluent upstream of the tailpipe. The system further includes an ozone generator and a flow line to feed ozone to the bypass filtration system.