Exhaust Gas Purification Unit Regeneration Control

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Solution Overview

Problem

Existing methods for regenerating diesel particulate filters in low-load or idling situations, such as in refuse removal trucks, often fail to achieve sufficient exhaust gas temperature and mass flow, risking filter destruction or incomplete regeneration due to inadequate consideration of exhaust gas properties.

Innovation Solution

A method that sets a predefined minimum engine speed and torque to ensure the exhaust gas mass flow and temperature exceed specific values during regeneration, thereby creating suitable conditions for filter regeneration, regardless of external temperature control measures.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Temperature

If the engine operates at high load for a longer time, then the exhaust gas temperature and mass flow are sufficient for regeneration, but the vehicle application (refuse removal truck) spends significant time on idle speed with short driving distances, resulting in relatively cool exhaust gas

Engineering Contradiction:
Improveexhaust gas temperatureVSAvoidadaptability to idle speed operation
Core Design Contradiction:
TemperatureVSAdaptability or versatility

Solution Approach 1:

The control system changes engine operating parameters (speed, load, injection timing) to achieve sufficient exhaust gas temperature and mass flow for regeneration even during idle speed operation. The controller monitors exhaust gas properties and adjusts parameters dynamically to maintain conditions suitable for filter regeneration.

Inventive Principle:
Principle #35Parameter changes

2Temperature

If fuel injection amount is increased or post-injection is used to increase exhaust gas temperature, then the temperature increases, but a sufficiently high temperature is normally not reached with such a measure alone

Engineering Contradiction:
Improveexhaust gas temperatureVSAvoidfuel consumption
Core Design Contradiction:
TemperatureVSUse of energy by moving object

Solution Approach 1:

The system changes multiple parameters simultaneously (engine speed, load, injection timing, injection amount) rather than relying solely on increasing fuel injection. This combination of parameter changes achieves higher temperature efficiency than fuel injection alone.

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The control system prepares the engine operating conditions in advance before regeneration is needed, adjusting parameters to build up sufficient exhaust gas temperature and mass flow, ensuring regeneration can proceed effectively when required.

Inventive Principle:
Principle #10Preliminary action

3Temperature

If a separate burner is used for heating up the filter in low-load or idling situations, then the filter can be heated to regeneration temperature, but this is a rather complicated solution requiring additional equipment such as the burner itself and an air compressor

Engineering Contradiction:
Improvefilter temperatureVSAvoidsystem complexity
Core Design Contradiction:
TemperatureVSDevice complexity

Solution Approach 1:

The engine itself serves to heat the filter for regeneration by controlling its own operating parameters to produce sufficient exhaust gas temperature and mass flow, eliminating the need for external burners and air compressors. The exhaust gas from the engine's normal operation is utilized for the regeneration process.

Inventive Principle:
Principle #25Self-service

Solution Approach 2:

The invention extracts and utilizes the heat energy already present in the exhaust gas from the engine's normal operation, rather than adding external heating equipment. The exhaust gas flow itself is harnessed to provide the necessary temperature for regeneration.

Inventive Principle:
Principle #2Taking out (Extraction)

4Reliability

If regeneration is attempted with insufficient exhaust gas mass flow, then the filter may be destroyed due to inadequate cooling and heat dissipation

Engineering Contradiction:
Improvefilter safetyVSAvoidregeneration efficiency
Core Design Contradiction:
ReliabilityVSProductivity

Solution Approach 1:

The control system continuously monitors exhaust gas properties (temperature, mass flow) and uses this feedback to determine when regeneration conditions are met. The controller adjusts engine parameters based on real-time measurements to ensure safe and effective regeneration, preventing filter destruction while maintaining productivity.

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 prevents filter destruction by maintaining sufficient exhaust gas mass flow and temperature, allowing for effective regeneration even in low-load situations, ensuring the regeneration process occurs safely and efficiently.

Implementation Method 1

a purification unit (13) arranged in an internal combustion engine system (1)

Methodology Applied
Scientific EffectFiltration: Filter (physical)

Implementation Method 2

To clean such a filter by injecting fuel and burning the particles, the temperature of the exhaust gas leaving the engine should normally be at least around 250°C

Methodology Applied
Scientific EffectCombustion: Combustion

Implementation Method 3

burning the particles

Methodology Applied
Scientific EffectOxidation: Oxidation

Implementation Method 4

The exhaust gas is therefore normally led through an after-treatment system adapted to purify the exhaust gas

Methodology Applied
Scientific EffectConvection: Convection

Implementation Method 5

if the temperature is too low the desired chemical reactions do not take place or the reaction rate becomes too low, and if the temperature is too high the components might be destroyed

Methodology Applied
Scientific EffectThermal conduction: Conduction (thermal)

Data Source

PatentEP2041406B2Method and system for regenerating an exhaust gas purification unit
Publication Date: 2021.03.03 VOLVO TRUCK CORP
  • EP2041406B2 patent drawingFigure 1
  • EP2041406B2 patent drawingFigure 2

AI summary

The invention concerns a method for regenerating an exhaust gas purification unit (13) arranged in an internal combustion engine system (1). The invention is characterized "in that the method comprises the step of setting a predefined minimum engine speed such that the exhaust gas mass flow exceeds a predefined flow value during the regeneration process. The invention also concerns an internal combustion engine system (1 ) comprising an exhaust gas purification unit (13) adapted to be operated according to said method.