Fuel Injection Control for Exhaust After-Treatment Temperature
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Internal combustion engine (ICE) exhaust after-treatment systems, particularly diesel particulate filters (DPF) and selective catalytic reduction (SCR) units, face challenges during low load and idle operations due to reduced exhaust temperatures, leading to increased fuel consumption, emissions, and the need for frequent regeneration cycles, which can reduce the lifespan of these components.
Innovation Solution
A method and control system that adjusts fuel injection in a four-stroke ICE to heat exhaust gases to a specific temperature by selectively regulating a group of cylinders, altering the fuel amount in consecutive induction strokes to maintain optimal exhaust temperatures for DPF and SCR unit operation, thereby reducing the need for parked regeneration and minimizing fuel consumption and emissions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If the engine operates with a rich air-fuel mixture during cold start to heat the EATS, then the EATS reaches operational temperature faster, but fuel consumption and engine emissions increase
Solution Approach 1:
The patent applies periodic action by alternately enriching and leaning the air-fuel mixture in a cyclic pattern. During specific cycles, the engine operates with a rich mixture to generate heat pulses in the exhaust, while other cycles use a lean mixture to reduce overall fuel consumption. This periodic enrichment strategy allows the EATS to reach operational temperature without continuously operating rich, thereby resolving the contradiction between heating the EATS and minimizing fuel consumption
Solution Approach 2:
The patent changes the air-fuel mixture parameter dynamically by adjusting the lambda value between rich (λ < 1) and lean (λ > 1) conditions based on EATS temperature requirements. The control system monitors EATS temperature and selectively enriches the mixture only when heating is required, rather than maintaining a consistently rich mixture. This parameter change approach enables efficient temperature management while minimizing unnecessary fuel consumption
2Reliability
If the engine performs parked regeneration to clean the DPF, then the DPF is regenerated successfully, but the vehicle requires stationary time and experiences increased fuel consumption
Solution Approach 1:
The patent implements continuous useful action by performing DPF regeneration during normal vehicle operation rather than requiring parked stationary regeneration. The control system continuously monitors DPF soot loading and initiates regeneration sequences during driving conditions when exhaust temperature and flow are sufficient. This approach maintains continuous vehicle operation while achieving DPF cleaning, eliminating the need for parked regeneration and associated downtime
Solution Approach 2:
The patent applies preliminary action by proactively managing DPF soot accumulation through periodic regeneration cycles before the filter becomes fully loaded. The control system monitors DPF status and initiates regeneration when soot loading reaches a threshold that would require parked regeneration if not addressed. This preliminary regeneration approach prevents the need for vehicle shutdown and parked regeneration, maintaining continuous operation
3Temperature
If the engine uses hot exhaust gas recirculation and intake air throttling to maintain EATS temperature, then the EATS functionality is maintained, but fuel consumption increases significantly
Solution Approach 1:
The patent uses periodic action by implementing intermittent exhaust gas recirculation rather than continuous operation. The control system activates EGR only during specific cycles or periods when exhaust temperature needs boosting, allowing the system to benefit from hot EGR heating without the continuous fuel penalty. This periodic EGR operation reduces overall fuel consumption compared to continuous EGR while still maintaining EATS functionality
Solution Approach 2:
The patent changes the EGR rate parameter dynamically based on operating conditions and EATS temperature requirements. Rather than maintaining a fixed high EGR rate, the control system adjusts the EGR percentage up or down depending on whether heating is needed and what the current engine load and temperature conditions are. This dynamic parameter adjustment optimizes the balance between maintaining exhaust temperature and minimizing fuel consumption
4Reliability
If frequent regeneration cycles are performed to keep the DPF clean, then the DPF back pressure is reduced, but the lifetime of the DPF and SCR unit is reduced
Solution Approach 1:
The patent implements feedback control by continuously monitoring DPF soot loading, exhaust temperature, and engine operating conditions to determine the optimal regeneration timing. The control system uses sensor feedback to assess when regeneration is truly necessary based on actual filter loading rather than operating on fixed time intervals. This feedback-based approach prevents unnecessary frequent regeneration cycles that would reduce component lifetime while still maintaining exhaust system performance when actually needed
Solution Approach 2:
The patent changes the regeneration frequency parameter dynamically based on actual DPF soot accumulation rates and operating conditions. Rather than performing regeneration on a fixed schedule, the control system adjusts regeneration timing based on monitored parameters such as differential pressure across the DPF, exhaust temperature profiles, and engine load patterns. This adaptive parameter adjustment optimizes the balance between maintaining performance and extending component lifetime by avoiding unnecessary regeneration cycles
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 the functionality of the exhaust after-treatment system during low load operations, reduces fuel consumption and emissions, extends the lifespan of DPF and SCR units, and minimizes the need for parked regeneration, while also providing heat for cabin heating, reducing the need for external heaters.
Implementation Method 1
heating exhaust gases to a selected specific temperature by fuel injection control in an internal combustion engine
Data Source
AI summary
The invention relates to a method to heat exhaust gases to a selected specific temperature by fuel injection control in an internal combustion engine (112), which engine comprises a control unit (115) registering the currently requested load and determining a required fuel amount in response to the requested load. The method involves registering low load operation of the internal combustion engine; registering an input from at least one exhaust after-treatment system (121) sensor indicating a detected condition; determining an exhaust temperature requirement for the detected condition and calculating a target exhaust temperature; selecting a group of cylinders to be regulated for achieving the target exhaust temperature; calculating a ratio for desired 1st and 2nd fuel amounts to be injected alternately in consecutive induction strokes for the selected group of cylinders to achieve the target exhaust temperature; wherein the ratio defines an offset between an increased 1st fuel amount to be injected in a cylinder of the selected group of cylinders for every second induction stroke, and a reduced 2nd fuel amount to be injected for the intermediate induction strokes.