DPF Abnormal Combustion Prevention via Throttle and Post-Injection Control
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Solution Overview
Problem
Existing aftertreatment systems for diesel engines fail to prevent abnormal temperature increases in Diesel Particulate Filters (DPFs) during rapid load changes, leading to potential breakage and thermal deterioration, and require unnecessary control measures that decrease combustion efficiency.
Innovation Solution
An exhaust gas treatment method that detects abnormal combustion conditions when shifting from high to low load conditions, increases exhaust gas flow by fully opening throttle valves, and reduces oxygen concentration to prevent temperature spikes, thereby maintaining efficient active regeneration and reducing fuel consumption.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If active regeneration is performed by post-injecting fuel to heat exhaust gas to combustion temperature, then particulate matter is burned and removed from the DPF, but the DPF internal temperature may increase abnormally when the engine shifts to low rotation low load operation
Solution Approach 1:
The control device predicts the possibility of abnormal temperature increase before it occurs by monitoring engine operation transitions. When a transition from high rotation/high load to low rotation/low load is detected during active regeneration, the system preemptively adjusts control parameters (throttle valve opening, post-injection amount) to prevent abnormal temperature rise before it happens
Solution Approach 2:
The control device continuously monitors engine operation parameters (rotation speed, load, exhaust gas temperature) and uses this feedback to determine whether abnormal temperature increase is likely. Based on this feedback, the system dynamically adjusts the throttle valve opening and post-injection fuel amount to maintain safe DPF temperatures while ensuring effective PM removal
2Reliability
If control measures are taken to prevent abnormal temperature increase in the DPF, then thermal deterioration is prevented, but combustion efficiency may decrease due to unnecessary control
Solution Approach 1:
The control device predicts the possibility of abnormal temperature increase before it occurs by monitoring engine operation transitions. When a transition from high rotation/high load to low rotation/low load is detected during active regeneration, the system preemptively adjusts control parameters (throttle valve opening, post-injection amount) to prevent abnormal temperature rise before it happens
Solution Approach 2:
The control device dynamically adjusts control parameters (throttle valve opening degree, post-injection fuel amount) based on the predicted possibility of abnormal temperature increase. By changing these parameters only when necessary (when abnormal temperature increase is predicted), the system prevents unnecessary control actions that would reduce combustion efficiency
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
Effectively prevents abnormal temperature increases in DPFs, preventing breakage and thermal deterioration, while maintaining combustion efficiency and reducing fuel consumption by accurately predicting and addressing abnormal combustion events.
Implementation Method 1
a diesel oxidation catalyst and a filter that collects particulate matter are provided in an exhaust pipe
Implementation Method 2
fuel is injected in an early post-injection. The fuel injected in the early post-injection is burned in a high-temperature atmosphere in the combustion cylinder
Implementation Method 3
an amount of heat removed from the DPF by the exhaust gas decreases
Data Source
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AI summary
In an exhaust gas treatment device in which a diesel oxidation catalyst and a DPF are provided in an exhaust pipe of an internal combustion engine, abnormal combustion in the DPF, occurring when the internal combustion engine varies from a high load condition to a low load condition, poses a problem. To solve this problem, in the present invention, a DPF abnormal combustion causing operation is determined to have occurred when the internal combustion engine shifts from a high rotation or high load operation region α to a low rotation, low load operation region β within a set time T1. When it is determined that a DPF abnormal combustion causing operation has occurred, abnormal combustion of PM collected in the DPF is suppressed by fully opening an intake throttle valve 44 in order to increase an exhaust gas flow so that heat is removed by sensible heat of the exhaust gas, thereby cooling a DPF device 52, and continuing a late post-injection in order to reduce an oxygen concentration of the DPF. As a result, an abnormal temperature increase in the DPF device 52 can be suppressed early.