SCR Catalyst Warmup Control via Exhaust Mass Flow Targeting
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Solution Overview
Problem
Internal combustion engines face challenges in balancing emissions regulations with the need for efficient catalyst heating during the warmup period, as the SCR catalyst is not at the desired temperature, leading to increased NOx and hydrocarbon emissions.
Innovation Solution
A system with a controller that determines a catalyst heating metric and controls the turbocharger, fuel injection system, or EGR system to reach a target value, ensuring the SCR catalyst reaches the desired temperature while minimizing NOx emissions, and diagnoses malfunctions by comparing the metric to a reference value.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-generated harmful factors
If the SCR catalyst is used to reduce NOx emissions, then emissions are reduced, but the catalyst is not at the desired temperature during warmup period, leading to increased emissions
Solution Approach 1:
The system changes operational parameters during warmup by determining a catalyst heating metric based on exhaust energy and emissions, then adjusting turbocharger, fuel injection, or EGR parameters to reach a target metric value that optimizes both catalyst heating and emissions reduction
Solution Approach 2:
The controller continuously monitors the catalyst heating metric and compares it to a target value, using this feedback to dynamically adjust engine operating parameters (turbocharger boost, fuel injection timing/quantity, EGR rate) to maintain optimal catalyst temperature while minimizing emissions
2Object-generated harmful factors
If the catalyst heating metric is monitored and controlled, then emissions are reduced and catalyst temperature is optimized, but the system complexity increases
Solution Approach 1:
The existing controller is enhanced to perform multiple functions: it calculates the catalyst heating metric using existing sensor data, determines target values based on operating conditions, controls multiple engine parameters (turbocharger, fuel injection, EGR), and performs fault diagnosis by comparing metric values to reference values, all within a single control unit
Solution Approach 2:
The system uses existing sensor measurements and engine operating data to self-determine the catalyst heating metric and automatically adjust parameters without requiring additional external intervention or complex auxiliary systems
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 NOx emissions during the warmup period by optimizing catalyst heating and identifies system malfunctions, ensuring compliance with emissions regulations and maintaining efficient engine operation.
Implementation Method 1
A common component in many of these exhaust aftertreatment systems is a selective catalytic reduction (SCR) system, which reduces a quantity of nitrous oxide (NOx) present in the exhaust gas by injecting a reductant into the flow of exhaust combined with the exhaust gas interacting with a catalyst. The catalyst reacts with the exhaust gas to form harmless nitrogen and water.
Data Source
AI summary
Systems and apparatuses include an engine, an aftertreatment system including a catalyst, and a controller coupled to the aftertreatment system and the engine. During a warmup period for an engine, the controller determines a value regarding a mass flow rate of exhaust gas based on information received from at least one of the engine or the aftertreatment system. The controller receives a target value regarding the mass flow rate of the exhaust gas. The controller controls at least one of the engine, the aftertreatment system, or at least one component associated therewith to reach or attempt to reach the target value regarding the mass flow rate of the exhaust gas.