SCR Catalyst Preheating Burner Control
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Selective catalytic reduction (SCR) catalysts in exhaust systems are ineffective at low engine startup temperatures, leading to high nitrogen oxides (NOx) emissions, as they require warming before engine startup to function optimally and have limited ammonia storage capacity, which decreases with increasing temperature.
Innovation Solution
An exhaust control system that includes a burner with a fuel injector, air pump, and spark plug to preheat the SCR catalyst before engine startup, using a mobile device's proximity or timed signals to initiate heating, and a DEF injector to begin ammonia production when the catalyst reaches a predetermined temperature, optimizing air-to-fuel ratios for lean combustion and minimizing emissions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-generated harmful factors
If the SCR catalyst is warmed before engine startup, then NOx emissions are reduced, but the burner component lifespan decreases
Solution Approach 1:
The system performs preliminary warming of the SCR catalyst before engine startup by activating the burner and air pump in advance. The control module detects upcoming startup conditions and initiates heating sequences that bring the catalyst to optimal temperature before the engine begins operation, ensuring immediate NOx reduction capability upon startup.
Solution Approach 2:
The system employs periodic heating cycles rather than continuous operation. The burner and air pump are activated in controlled intervals to reach target temperatures, then allowed to cycle off, reducing thermal stress on components while maintaining catalyst effectiveness. This periodic operation extends burner lifespan while achieving the necessary warming.
2Temperature
If the air pump is activated before engine startup, then SCR catalyst heating is improved, but energy consumption increases
Solution Approach 1:
The air pump is activated in advance of engine startup to establish the necessary airflow for burner operation and catalyst heating. The control module timing ensures the pump runs only during the preheating phase, stopping before startup to minimize energy consumption while ensuring the catalyst is ready for immediate operation.
Solution Approach 2:
The system dynamically adjusts air pump operation based on real-time temperature feedback from the SCR catalyst. The pump speed and duration are optimized to reach target temperatures efficiently, reducing unnecessary energy consumption while maintaining effective heating performance.
3Speed
If fuel injection is increased for burner heating, then SCR catalyst warming speed increases, but fuel consumption increases
Solution Approach 1:
The fuel injector operates in periodic cycles during the preheating phase, delivering fuel in controlled bursts rather than continuous injection. This allows the burner to maintain high temperatures during active heating cycles while reducing overall fuel consumption during transition and maintenance phases.
Solution Approach 2:
The system dynamically adjusts fuel injection parameters including quantity, timing, and duration based on real-time catalyst temperature feedback. The control module optimizes the air-to-fuel ratio and injection timing to achieve maximum heating efficiency at minimum fuel consumption, adapting parameters as the catalyst approaches target temperature.
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 by warming the SCR catalyst before engine startup, maximizing ammonia storage and reducing NOx output after startup, while also extending the lifespan of burner components through controlled airflow and temperature management.
Implementation Method 1
The burner combusts air and fuel to warm the SCR catalyst
Implementation Method 2
a spark plug configured to ignite an air/fuel mixture within the combustion chamber of the burner
Implementation Method 3
The air pump delivers air to the combustion chamber and exhaust system
Implementation Method 4
a fuel injector configured to inject fuel into the combustion chamber of the burner
Data Source
AI summary
An exhaust control system of a vehicle includes a fuel injector configured to inject fuel into a combustion chamber of a burner of an exhaust system upstream of a selective catalytic reduction (SCR) catalyst; an air pump configured to pump air into the combustion chamber of the burner; a spark plug configured to ignite an air/fuel mixture within the combustion chamber of the burner; a fuel control module configured to, while an engine is off before an engine startup, selectively actuate the fuel injector and begin fuel injection; a pump control module configured to, while the engine is off before the engine startup, selectively turn on the air pump; and a spark control module configured to, while the engine is off and before the engine startup, selectively apply power to the spark plug and begin providing spark.