Exhaust Line Thermal Protection via Richness Setpoint Control

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Solution Overview

Problem

Existing methods fail to effectively control and protect the components of a heat engine's exhaust line from excessive temperature, which can lead to damage, particularly in gasoline engines with direct or indirect injection, as they do not adequately manage the thermal conditions across the exhaust system.

Innovation Solution

A process that determines a setpoint temperature for the exhaust gases and develops a richness setpoint to ensure this temperature is not exceeded, using prepositioning and regulation maps based on engine parameters, and inverting models of the exhaust line to calculate the necessary enrichment, thereby protecting components from thermal damage.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Power

If the exhaust gas temperature is allowed to increase to improve engine efficiency, then power output is improved, but the temperature of exhaust line components may exceed critical temperature and cause damage

Engineering Contradiction:

Improveengine power outputVSAvoidthermal damage to exhaust line components

Core Design Contradiction:

PowerVSObject-affected harmful factors

Solution Approach 1:

The system performs preliminary identification of which exhaust line component is closest to its maximum temperature limit and pre-calculates the required richness setpoint to prevent temperature exceedance. This proactive approach allows the engine to operate at optimal power levels while preventing thermal damage before it occurs.

Inventive Principle:

Principle #10Preliminary action

Solution Approach 2:

The system continuously monitors exhaust gas temperature and component temperatures, compares them against maximum limits, and dynamically adjusts the richness setpoint based on feedback from temperature sensors. This closed-loop control ensures power optimization while maintaining thermal safety of exhaust line components.

Inventive Principle:

Principle #23Feedback

2Object-affected harmful factors

If enrichment of combustion is increased to reduce exhaust gas temperature, then thermal protection is improved, but CO2 emissions increase

Engineering Contradiction:

Improvethermal protection of exhaust line componentsVSAvoidCO2 emissions

Core Design Contradiction:

Object-affected harmful factorsVSLoss of energy

Solution Approach 1:

The system applies enrichment selectively and locally - it enriches combustion only to the extent necessary to protect the specific exhaust line component that is closest to its temperature limit. This targeted approach minimizes CO2 emissions while providing adequate thermal protection, avoiding unnecessary enrichment across all operating conditions.

Inventive Principle:

Principle #3Local quality

Solution Approach 2:

The system dynamically changes the richness parameter based on real-time temperature measurements and component thermal states. By continuously adjusting the richness setpoint to match actual thermal conditions, the system minimizes enrichment (and thus CO2 emissions) while maintaining adequate thermal protection of exhaust line components.

Inventive Principle:

Principle #35Parameter changes

3Object-affected harmful factors

If maximum richness is used to protect exhaust line components, then thermal protection is improved, but engine performance deteriorates

Engineering Contradiction:

Improvethermal protection of exhaust line componentsVSAvoidengine performance

Core Design Contradiction:

Object-affected harmful factorsVSPower

Solution Approach 1:

The system applies partial enrichment rather than maximum enrichment - it uses only the amount of richness necessary to protect exhaust line components from thermal damage. By applying the minimum necessary enrichment to achieve thermal protection, the system maintains engine performance while preventing component damage.

Inventive Principle:

Principle #16Partial or excessive action

Solution Approach 2:

The system dynamically adjusts the richness setpoint based on real-time operating conditions and thermal states of exhaust line components. Rather than using fixed maximum richness, the system optimizes enrichment levels continuously, maintaining engine performance while providing thermal protection when and where needed.

Inventive Principle:

Principle #15Dynamics

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 limits exhaust gas temperatures at the engine outlet, preventing component damage by determining the optimal enrichment level, reducing CO2 emissions, and minimizing calibration costs by leveraging existing direct models without additional testing.

Implementation Method 1

the fuel/air mixture

Methodology Applied

Scientific EffectCombustion: Combustion

Data Source

PatentEP2807353B1Method for thermal protection of the exhaust line of an internal combustion engine

Publication Date: 2017.03.08 PSA AUTOMOBILES SA

AI summary

The invention relates to a method for the thermal protection of the components of the exhaust line of a heat engine according to which the temperatures of the exhaust gases and the walls of the exhaust line are predetermined and according to which, when the component of the exhaust line has reached the maximum temperature limit thereof, this is detected. According to the invention, the method consists of: - determining (54) a setpoint temperature (T3setpoint) of the exhaust gases at the outlet of said engine, and - developing (56) a setpoint richness (ϕsetpoint) used to ensure said setpoint temperature of the exhaust gases.