Internal Combustion Engine Aftertreatment Temperature Control
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Solution Overview
Problem
Internal combustion engine exhaust aftertreatment systems face inefficiencies in emission reduction at low temperatures, leading to fouling and inadequate performance due to unburned hydrocarbons and NOx formation, as they often operate below their activation temperature.
Innovation Solution
The system injects fuel into fewer combustion cylinders, directing exhaust through the aftertreatment system while diverting uncombusted gas away, thereby raising the exhaust and aftertreatment system temperatures, and employs an auxiliary load through an orifice to increase engine torque and temperature, ensuring the aftertreatment system operates above its activation temperature.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of energy
If the engine operates under light load, low speed conditions, then fuel consumption is reduced, but exhaust temperature decreases below activation temperature
Solution Approach 1:
The exhaust system is segmented into multiple pathways: a first pathway directs exhaust from fueled cylinders through the aftertreatment system, while a second pathway directs uncombusted gas from non-fueled cylinders away from the aftertreatment system. This segmentation allows selective routing of hot exhaust to maintain aftertreatment temperature while reducing overall fuel consumption.
Solution Approach 2:
The system changes the operational parameters of different cylinders: some cylinders are fueled and combusted to generate hot exhaust, while other cylinders receive uncombusted gas. This parameter change creates temperature differentiation that enables the aftertreatment system to operate above activation temperature even during light load conditions.
2Power
If fuel is injected into all combustion cylinders, then power output is maintained, but aftertreatment system temperature remains below activation temperature
Solution Approach 1:
The system extracts uncombusted gas from non-fueled cylinders and directs it away from the aftertreatment system through a separate pathway. This extraction prevents the cooling effect of uncombusted gas from lowering the aftertreatment system temperature below the activation threshold.
Solution Approach 2:
The cylinder group is segmented into fueled cylinders and non-fueled cylinders. Exhaust from fueled cylinders is routed through the aftertreatment system to maintain temperature, while uncombusted gas from non-fueled cylinders is diverted through a separate pathway, enabling temperature control while maintaining overall power output.
3Quantity of substance
If the aftertreatment system operates below activation temperature, then emissions may be reduced in quantity, but the system becomes fouled by unburned hydrocarbons
Solution Approach 1:
The system takes preliminary action by directing hot exhaust from fueled cylinders through the aftertreatment system before uncombusted gas from non-fueled cylinders can enter. This preliminary heating action prevents the subsequent entry of cold uncombusted gas from causing fouling, maintaining system reliability.
Solution Approach 2:
The system maintains continuous useful action by ensuring hot exhaust continuously flows through the aftertreatment system from fueled cylinders. This continuous thermal input keeps the aftertreatment system above activation temperature, preventing the conditions that lead to hydrocarbon adsorption and fouling.
4Quantity of substance
If uncombusted gas is directed through the aftertreatment system, then emissions are diluted, but the system temperature drops below activation temperature
Solution Approach 1:
The exhaust system is segmented into two separate pathways: one for hot exhaust from fueled cylinders that maintains aftertreatment temperature, and another for uncombusted gas from non-fueled cylinders that is directed away from the aftertreatment system. This segmentation prevents temperature dilution while still allowing emission control.
Solution Approach 2:
Uncombusted gas is extracted from the exhaust stream at the cylinder source and directed through a separate pathway away from the aftertreatment system. This extraction prevents the cooling effect of uncombusted gas from dropping the aftertreatment system temperature below activation 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
This method enhances the aftertreatment system's performance by increasing exhaust gas temperature, reducing unburned hydrocarbons, and limiting NOx formation, ensuring effective emission reduction and preventing fouling, even under low load and cold conditions.
Implementation Method 1
Combusting the quantity of fuel in fewer than all of the plurality of combustion cylinders raises the combustion temperature, thereby raising the exhaust temperature
Implementation Method 2
Exhaust from the fueled cylinders is directed through the aftertreatment system... raising the exhaust and aftertreatment system temperatures
Implementation Method 3
The uncombusted gas may be directed into an intake manifold in fluid communication with the plurality of combustion cylinders through an orifice, thereby applying an auxiliary load to the engine
Data Source
AI summary
A system and method are disclosed for improving the performance of an aftertreatment system by elevating its temperature above an activation temperature. According to at least one aspect of the present disclosure, the method includes injecting a quantity of a fuel into certain fueled cylinders of a plurality of combustion cylinders of an internal combustion engine, the plurality of combustion cylinders further including non-fueled cylinders. Exhaust from the fueled cylinders is directed through the aftertreatment system while uncombusted gas from the non-fueled cylinders is directed away from the aftertreatment system. In certain embodiments, the uncombusted gas may be directed into an intake manifold in fluid communication with the plurality of combustion cylinders through an orifice. The system includes an engine having exhaust valves to control flow of the exhaust and uncombusted gas and a controller configured to perform the operations of the method.