Dual EGR Loop Control for Filter Clogging Prevention
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Solution Overview
Problem
Internal combustion engines with dual EGR loops face issues with clogged low-pressure EGR filters leading to premature maintenance and increased emissions, as existing methods fail to effectively manage the recirculation rates to prevent filter clogging and maintain emissions neutrality.
Innovation Solution
A method that dynamically adjusts the proportions of high-pressure and low-pressure exhaust gas recirculation rates based on operating parameters and pressure differences across the EGR filter, ensuring the total EGR rate meets predetermined values while keeping the pressure difference below critical thresholds, thereby extending maintenance intervals and preventing engine malfunctions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a low-pressure EGR filter is used to trap residues, then the compressor is protected from damage, but the filter becomes clogged during operation leading to increased pressure loss and engine malfunctions
Solution Approach 1:
The system dynamically adjusts the LP-EGR rate based on the differential pressure across the filter. When pressure loss increases due to clogging, the control unit reduces the LP-EGR valve opening to maintain pressure difference and prevent complete blockage, thereby adapting the system behavior to the filter's deteriorating state
Solution Approach 2:
The control unit changes the operating parameters by adjusting the LP-EGR rate and switching between HP-EGR and LP-EGR modes based on the differential pressure threshold. This parameter adjustment allows the system to operate effectively while managing filter clogging progression
2Object-generated harmful factors
If the LP-EGR rate is increased to meet total EGR rate requirements, then emissions are reduced, but the pressure difference across the filter increases leading to faster clogging
Solution Approach 1:
The differential pressure sensor provides continuous feedback on the filter's clogging state. The control unit uses this feedback to adjust the LP-EGR rate, reducing it when pressure difference approaches the threshold and maintaining higher rates when the filter is clean, thus balancing emissions control with filter protection
Solution Approach 2:
The system transitions from a static EGR control approach to a dynamic one where the LP-EGR rate continuously adapts to the filter's actual condition, allowing maximum emissions reduction when the filter is clean and progressive reduction as clogging occurs
3Duration of action of stationary object
If the differential pressure threshold is set low to prevent filter clogging, then maintenance intervals are extended, but the LP-EGR rate must be reduced limiting emissions control effectiveness
Solution Approach 1:
The system changes the control parameter (LP-EGR rate) based on the actual filter condition indicated by differential pressure. By setting the threshold appropriately and dynamically adjusting rates, the system achieves both extended maintenance intervals through proactive monitoring and maintained emissions control through adaptive compensation using HP-EGR
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 delays the need for maintenance by managing EGR rates to keep emissions neutral, reducing the risk of engine malfunctions and lowering operational costs by maintaining optimal engine performance and reducing emissions.
Implementation Method 1
in the LP-EGR loop the exhaust gas is cleaned by a low-pressure exhaust gas recirculation filter (LP-EGR filter)
Implementation Method 2
a compressor of the exhaust gas turbocharger driven by the turbine and arranged in a combustion air system of the internal combustion engine compresses combustion air
Implementation Method 3
a turbine of an exhaust gas turbocharger arranged in an exhaust system of the internal combustion engine is driven by exhaust gas from the internal combustion engine
Data Source
Figure 1
Figure 2~3
AI summary
The method involves diverting exhaust gas in upstream and dowstream of high and low pressure exhaust gas recirculation loops (46, 54) from a turbine (36). The exhaust gas is purified by a low pressure exhaust gas recirculation filter (48) in the low recirculation loop. A preset value for a total exhaust gas recirculation flow is determined as a function of an operating state of an internal combustion engine. Portions of low and high pressure exhaust gas recirculation flows of a total exhaust gas recirculation flow are determined as a function of a value of an operating parameter. An independent claim is also included for a control unit for an internal combustion engine.