Diesel Post-Injection Timing for Exhaust Regeneration
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Solution Overview
Problem
Diesel engine after treatment device regeneration is hindered by low exhaust temperatures, and existing methods for post injection control are not accurate enough to prevent fuel from impinging on cylinder walls in liquid form, leading to engine degradation and emissions issues.
Innovation Solution
Adjusting the amount of post injection fuel based on cylinder mixture density and temperature to improve fuel spray penetration estimates, and considering cylinder volumetric efficiency to optimize the timing of fuel injection, ensuring that fuel does not impinge on the cylinder walls in liquid form.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If fuel is injected late in the cylinder cycle (during exhaust stroke) to increase exhaust system temperature for after treatment device regeneration, then exhaust temperature increases, but liquid fuel impinges on cylinder walls causing engine degradation and oil dilution
Solution Approach 1:
The patent adjusts the fuel injection timing parameter based on cylinder temperature and density conditions. By monitoring these parameters and modifying injection timing accordingly, the system optimizes fuel spray penetration to prevent wall impingement while maintaining sufficient exhaust temperature for after treatment device regeneration.
Solution Approach 2:
The patent implements a feedback control system that monitors cylinder temperature and density, then adjusts fuel injection timing in response. This closed-loop approach ensures that injection timing is optimized in real-time to prevent fuel from impinging on cylinder walls while still achieving the desired exhaust temperature increase.
2Object-affected harmful factors
If fuel injection timing is adjusted to prevent fuel spray from impinging on cylinder walls, then fuel wall impingement is reduced, but exhaust temperature may not increase sufficiently for after treatment device regeneration
Solution Approach 1:
The patent dynamically adjusts multiple parameters including injection timing, injection duration, and fuel quantity based on real-time cylinder temperature and density measurements. This multi-parameter optimization allows the system to prevent wall impingement while ensuring sufficient fuel combustion to raise exhaust temperatures for after treatment device regeneration.
3Productivity
If larger amounts of fuel are injected to improve after treatment device regeneration, then regeneration effectiveness increases, but fuel spray penetration increases causing more fuel to reach cylinder walls in liquid form
Solution Approach 1:
The patent optimizes the fuel injection parameters (timing, duration, quantity) as a coordinated set rather than adjusting them independently. By changing multiple parameters simultaneously based on cylinder conditions, the system achieves sufficient fuel combustion for effective after treatment device regeneration while controlling spray penetration to prevent liquid fuel from reaching cylinder walls.
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 reduces engine degradation, emissions, and oil dilution, allowing for larger fuel injection amounts without wall impingement, and can extend engine oil change intervals without requiring costly in-cylinder sensors.
Implementation Method 1
inject fuel late in a cylinder cycle (e.g., during an exhaust stroke) so that the fuel can oxidize in the exhaust system, thereby increasing the exhaust system temperature
Implementation Method 2
Cylinder mixture density and temperature provide a more accurate estimate of fuel spray penetration than cylinder pressure or injector delta pressure since cylinder mixture density and temperature account for both fuel evaporation and momentum transfer
Implementation Method 3
Cylinder mixture density and temperature provide a more accurate estimate of fuel spray penetration than cylinder pressure or injector delta pressure since cylinder mixture density and temperature account for both fuel evaporation and momentum transfer
Data Source
AI summary
Methods and systems for regenerating an after treatment device are disclosed. In one example, the possibility of introducing fuel to oil during after treatment device regeneration is reduced. The methods and systems may reduce engine degradation and improve engine emissions.