Diesel Soot Filter Temperature Control via Oxygen-Constrained Fuel Injection
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Solution Overview
Problem
Conventional diesel exhaust systems face challenges in efficiently regenerating catalyst soot filters due to insufficient exhaust gas temperatures under certain load conditions, which hinder the effective burning of soot into less harmful materials.
Innovation Solution
The system employs an Engine Control Module (ECM) that determines the target light-off temperature based on current exhaust flow, using a feed-forward model and PID controller to calculate and adjust fuel injection, ensuring the exhaust gas reaches the necessary temperature for soot regeneration by generating a combined fuel injection value that maintains optimal temperature and oxygen conditions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If fuel injection is increased to raise exhaust gas temperature for soot regeneration, then temperature reaches required levels, but oxygen concentration decreases below levels needed for efficient combustion
Solution Approach 1:
The system implements feedback control by continuously monitoring both exhaust gas temperature and oxygen concentration, then adjusting fuel injection and exhaust flow valve positions dynamically to maintain both parameters within optimal ranges for soot regeneration
Solution Approach 2:
The system changes operating parameters (fuel injection quantity and exhaust flow valve position) based on real-time measurements of temperature and oxygen levels, adapting the regeneration process to maintain optimal conditions despite varying engine loads
2Temperature
If exhaust flow is restricted to increase temperature for soot burning, then temperature reaches light-off levels, but oxygen supply is reduced hindering combustion efficiency
Solution Approach 1:
The exhaust flow valve is dynamically adjusted based on real-time temperature and oxygen measurements, allowing the system to optimize the balance between temperature maintenance and oxygen supply for efficient soot combustion under varying conditions
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 ensures consistent and efficient soot regeneration in catalyst soot filters, even under varying engine conditions, by precisely controlling fuel injection to achieve and maintain the required temperature and oxygen levels for effective soot conversion.
Implementation Method 1
combustion of the first amount of fuel thereby causing the first temperature signal to approach the target light off temperature
Implementation Method 2
the ECM includes a first PID controller that generates, based on the first difference signal, a first error signal that is added to the calculated first amount of fuel
Data Source
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Figure 2
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AI summary
A system and method for controlling soot regeneration in a catalyst soot filter ("CSF") (16) of an exhaust system (10) for a diesel engine (12) by measuring the inlet temperature of a diesel oxidation catalyst ("DOC") (14) coupled to the CSF (16), determining a target light off temperature for the DOC (14), injecting a first fuel amount into a cylinder of the engine (12) to cause the DOC (14) inlet temperature to approach the target light off temperature, measuring the CSF (16) inlet temperature and pressure across the CSF (16), determining a target CSF (16) inlet temperature for regeneration, injecting a second fuel amount for combustion in the DOC (14) to cause the CSF (16) inlet temperature to approach the target CSF (16) inlet temperature.