Engine Fueling for Thermal Management of Exhaust Catalysts
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Exhaust aftertreatment systems in internal combustion engines face performance deterioration due to low exhaust gas temperatures, which can lead to the buildup of harmful species in catalysts and reductant piping systems, necessitating periodic high-temperature operations to maintain healthy catalyst conditions.
Innovation Solution
A method and system that increase the engine load by adjusting fuel flow rate and pressure to raise exhaust gas temperatures above predefined thresholds, using a controller and fuel metering device to divert excess fuel, ensuring continuous real-time manipulation of fuel flow to maintain optimal operating conditions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If the engine operates at low speed or low load to meet performance requirements, then fuel consumption is reduced, but exhaust gas temperature drops below the threshold needed for healthy catalyst operation
Solution Approach 1:
The system implements periodic thermal management by alternating between normal operation and high-temperature regeneration cycles. The controller monitors catalyst temperature and periodically increases engine load or fuel injection to raise exhaust temperature above the threshold, then returns to normal operation, creating a periodic action pattern that maintains catalyst health over time.
Solution Approach 2:
The system changes operating parameters by adjusting engine load, fuel injection rate, or exhaust flow rate to raise exhaust gas temperature. The controller modifies these parameters dynamically based on temperature sensor feedback, transitioning the system from low-temperature operation to high-temperature regeneration mode when catalyst temperature drops below the threshold.
2Reliability
If the engine operates at high temperature to maintain healthy catalyst conditions, then catalyst performance is preserved, but fuel consumption increases
Solution Approach 1:
The system maintains continuous catalyst protection by monitoring temperature continuously and initiating high-temperature operation whenever the threshold is approached. This ensures uninterrupted catalyst health maintenance without allowing temperature to drop below functional levels, providing continuous useful action for emissions control.
Solution Approach 2:
The system uses the engine's own exhaust heat and combustion process to regenerate the catalyst, rather than requiring external heating systems. The controller leverages the engine's natural thermal output and combustion energy to raise exhaust temperature, making the system self-sufficient for thermal management.
3Reliability
If periodic high-temperature operation is implemented to prevent species buildup in catalysts, then catalyst performance is maintained, but system complexity increases
Solution Approach 1:
The system implements feedback control by using temperature sensors to monitor exhaust gas or catalyst temperature and feeding this information back to the controller. The controller automatically adjusts engine operation based on this feedback, creating a closed-loop system that maintains catalyst temperature within the required range without manual intervention.
Solution Approach 2:
The system uses existing engine components (fuel injection system, engine control unit, exhaust manifold) for thermal management, making these components serve dual functions: normal engine operation and catalyst heating. This multi-functionality avoids adding dedicated heating equipment, reducing overall system complexity.
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 effectively maintains healthy catalyst conditions by ensuring exhaust gas temperatures are consistently above thresholds, preventing performance deterioration and promoting efficient operation of exhaust aftertreatment systems.
Implementation Method 1
increasing at least one of a fuel flow rate and a fuel flow pressure of a fuel pump powered by the engine
Implementation Method 2
exhaust gas emitted from an engine operating at an engine speed below a predetermined speed threshold or a low engine load
Implementation Method 3
one or more catalysts that reduce an emission of particulate matter, nitrogen oxides (NOx), hydrocarbons, and other environmentally harmful pollutants
Data Source
AI summary
A method includes receiving information indicative of a temperature of exhaust gas emitted from an engine operating at an engine speed, determining that the temperature of the exhaust gas is below a predefined temperature threshold, determining an engine load sized to increase the temperature of the exhaust gas above the predefined temperature threshold, increasing a load on the engine to the determined engine load while maintaining the engine at the engine speed by increasing at least one of a fuel flow rate and a fuel flow pressure of the fuel pump powered by the engine, and diverting the excess fuel from the fuel flow path upstream of the engine. Increasing at least one of the fuel flow rate and the fuel pressure of the fuel pump causes excess fuel to be provided to the engine than is necessary to maintain the engine at the engine speed.