Predictive Control for Engine NOx and CO2 Emission Trade-off

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Solution Overview

Problem

Combustion engines face a challenge in simultaneously reducing nitrogen oxide (NOx) and carbon dioxide (CO2) emissions, as measures that enhance combustion efficiency to lower CO2 emissions often increase NOx emissions, and vice versa, necessitating a method to optimize both emissions simultaneously while adhering to legal limits.

Innovation Solution

A predictive model-based control method that uses a selected prediction horizon, weighting factors, and correction factors to minimize a cost function incorporating NOx and CO2 emissions, adjusting regeneration strategies and heating measures for the catalytic converters, ensuring NOx emissions remain within legal limits while optimizing CO2 reduction.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Loss of energy

If combustion efficiency is increased to reduce carbon dioxide emissions, then carbon dioxide emissions are reduced, but nitrogen oxide emissions increase

Engineering Contradiction:

Improvecarbon dioxide emissionsVSAvoidnitrogen oxide emissions

Core Design Contradiction:

Loss of energyVSObject-generated harmful factors

Solution Approach 1:

The patent implements dynamic adjustment of setpoint values for engine actuators based on real-time traffic situations and driving behavior. The control system continuously adapts combustion parameters to optimize the trade-off between CO2 and NOx emissions under varying operating conditions, rather than using fixed optimization settings

Inventive Principle:

Principle #15Dynamics

Solution Approach 2:

The system changes combustion parameters dynamically by adjusting setpoint values for actuators based on measured traffic conditions and driving patterns. This allows the engine to operate at optimal points that balance CO2 reduction with NOx control for each specific situation

Inventive Principle:

Principle #35Parameter changes

2Object-generated harmful factors

If nitrogen oxide emissions are reduced using SCR or NSC systems, then nitrogen oxide emissions are reduced, but carbon dioxide emissions increase due to additional fuel consumption

Engineering Contradiction:

Improvenitrogen oxide emissionsVSAvoidcarbon dioxide emissions

Core Design Contradiction:

Object-generated harmful factorsVSLoss of energy

Solution Approach 1:

The system performs preliminary analysis of traffic situations and driving behavior to predict when NOx reduction measures will be most effective. By planning regeneration processes and SCR/NSC operations based on forecasted driving conditions, the system minimizes unnecessary fuel consumption while ensuring NOx limits are met

Inventive Principle:

Principle #10Preliminary action

Solution Approach 2:

The control system continuously monitors actual emissions, traffic conditions, and component states to adjust NOx reduction strategies in real-time. This feedback mechanism allows the system to optimize the balance between NOx reduction effectiveness and CO2 emissions by adapting to changing operating conditions

Inventive Principle:

Principle #23Feedback

3Object-generated harmful factors

If characteristic fields are used for implicit emission control, then emissions are controlled based on load and revolution rate, but individual driving behavior and traffic situations are not adequately considered

Engineering Contradiction:

Improveemissions controlVSAvoidadaptation to driving behavior and traffic situations

Core Design Contradiction:

Object-generated harmful factorsVSAdaptability or versatility

Solution Approach 1:

The system automatically analyzes driving behavior patterns and traffic situations without requiring manual input. It self-adjusts the emission control strategy based on measured data from sensors and navigation systems, making the control system adaptable to individual driving styles and specific traffic conditions

Inventive Principle:

Principle #25Self-service

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 allows for goal-oriented control of combustion engines and exhaust gas aftertreatment systems, effectively reducing harmful emissions by determining optimal weighting and correction factors, ensuring compliance with NOx limits and minimizing CO2 emissions.

Implementation Method 1

oxides of nitrogen are mainly reduced by means of the SCR method (Selective Catalytic Reduction)

Methodology Applied

Scientific EffectSelective catalytic reduction: Catalysis

Implementation Method 2

using NOx storage catalytic converters (NSC)

Methodology Applied

Scientific EffectAdsorption: Adsorption

Implementation Method 3

an indicator for requesting heating measures for the catalytic converters

Methodology Applied

Scientific EffectHeating: Heating

Data Source

PatentUS10787944B2Method for optimizing nitrogen oxide emissions and carbon dioxide emissions of a combustion engine

Publication Date: 2020.09.29 ROBERT BOSCH GMBH

AI summary

A method for simultaneous optimization of nitrogen oxide emissions and carbon dioxide emissions of a combustion engine with an exhaust gas aftertreatment system of a motor vehicle. The method comprises the following steps: at the start a prediction horizon (PH) is selected (100), then a nitrogen oxide limit value (mNOx_max) is specified (101). Minimisation (102) of a cost function (K) comprising the nitrogen oxide emissions and the carbon dioxide emissions is carried out, wherein the nitrogen oxide limit value (mNOx_max) is complied with. Then actuators of the combustion engine are set (105) to a setpoint value (S) that is determined when minimizing (102) the cost function (K). Finally, the steps of the method are repeated.