Heating Catalyst Control for Stable Exhaust Aftertreatment Temperature
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Solution Overview
Problem
Existing methods for heating components of exhaust-gas aftertreatment devices in internal combustion engines suffer from fluctuations in heat emission due to varying exhaust-gas mass flow and composition, leading to inefficient temperature control and potential emission slip.
Innovation Solution
A method involving a heating catalyst that reacts a partial exhaust-gas flow with fuel, controlling the fuel and flow based on exhaust-gas temperature and engine operating conditions using a characteristic map, allowing for open-loop or closed-loop control without direct temperature sensors.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If a heating catalyst is used to generate heat by reacting exhaust gas with fuel, then the temperature of exhaust-gas aftertreatment components can be increased, but large fluctuations in heat emission occur due to varying exhaust-gas mass flow and composition
Solution Approach 1:
The patent implements a control device that continuously monitors the actual exhaust-gas temperature and compares it with a desired temperature. Based on this feedback, the control device adjusts the fuel supply amount to the heating catalyst to compensate for fluctuations in heat emission caused by varying exhaust-gas conditions, thereby stabilizing the temperature of aftertreatment components.
Solution Approach 2:
The patent changes the parameter of fuel supply amount to the heating catalyst based on detected operating conditions. By dynamically adjusting this parameter in response to varying exhaust-gas mass flow and composition, the system compensates for heat emission fluctuations and maintains stable component temperatures.
2Temperature
If internal engine measures are used to raise exhaust-gas temperature, then heat is introduced into aftertreatment components, but efficiency and pollutant emissions of the engine are adversely affected
Solution Approach 1:
The patent introduces a heating catalyst as an intermediary device between the engine and the aftertreatment components. Instead of modifying engine operation to raise exhaust temperature, the heating catalyst uses a partial flow of exhaust gas reacted with fuel to generate heat locally, thereby introducing heat into the aftertreatment components without adversely affecting engine efficiency or emissions.
Solution Approach 2:
The patent segments the exhaust-gas flow, directing only a partial flow through the heating catalyst while the majority of exhaust gas bypasses this heating zone. This segmentation allows heat generation in the aftertreatment components without requiring the entire exhaust system to be modified, preserving engine efficiency while achieving the desired temperature increase in specific components.
3Measurement precision
If temperature sensors are used for direct measurement of exhaust-gas temperature, then accurate temperature control is achieved, but device complexity and cost increase
Solution Approach 1:
The patent replaces the mechanical/physical system of direct temperature measurement with temperature sensors with a calculation-based approach. The control device determines the exhaust-gas temperature by calculating from operating parameters of the internal combustion engine and heat emission characteristics of the heating catalyst, thereby achieving accurate temperature control without the complexity and cost of direct temperature sensing in the exhaust stream.
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 stabilizes the temperature of exhaust-gas aftertreatment components, ensuring efficient operation with reduced energy consumption and minimal emissions, even under dynamic load conditions.
Implementation Method 1
a partial flow of an exhaust-gas flow is at least partially reacted with fuel in a heating catalyst and fed back to the exhaust-gas flow
Implementation Method 2
heat can be generated, on the one hand, by an exothermic reaction independently of the operation of the internal combustion engine and fed to the exhaust-gas aftertreatment device
Implementation Method 3
at least one component which purifies the raw exhaust gas of the internal combustion engine. This purification often comprises a catalytic post-oxidation
Implementation Method 4
catalytic post-oxidation, the filtering of particles or the catalytic reaction of nitrogen oxides with a reducing agent
Implementation Method 5
the filtering of particles or the catalytic reaction of nitrogen oxides with a reducing agent
Implementation Method 6
the catalytic reaction of nitrogen oxides with a reducing agent
Implementation Method 7
the catalytic reaction of nitrogen oxides with a reducing agent
Data Source
AI summary
A method for introducing heat into an exhaust-gas aftertreatment device connected to an internal combustion engine which outputs an exhaust-gas flow is disclosed. The exhaust-gas aftertreatment device may comprise one or more of an oxidation catalyst component, a particulate filter component and an SCR system component, the method comprising: at least partially reacting a partial flow of the exhaust-gas flow with fuel in a heating catalyst and feeding the reacted partial flow back into the exhaust-gas flow; and controlling the amount of fuel fed to the heating catalyst and/or the partial flow of exhaust-gas flow fed to the heating catalyst based on an exhaust-gas temperature upstream and/or downstream of said one or more components in accordance with at least one heating-catalyst characteristic map, wherein the exhaust-gas temperature upstream and/or downstream of said one or more components is indirectly determined from an operating state of the internal combustion engine, without direct measurement by temperature sensors. A computer readable medium stores a signal sequence representing data suitable for transmission by means of a computer network, to an open-loop or closed-loop control device to carry out the abovedescribed method.