Exhaust Pipe Injection PID Control for Regeneration Stability
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Solution Overview
Problem
Existing exhaust gas purification systems face challenges in accurately controlling exhaust pipe injection during traveling automatic regeneration, especially with repeated acceleration and deceleration, leading to unstable exhaust gas temperatures and incomplete regeneration due to PID control recalculations and injector contamination.
Innovation Solution
The system continues PID control integration even when the exhaust brake valve is closed during traveling automatic regeneration, using the accumulated integral control term as the initial operation amount upon reopening, and resets PID control when the brake valve is continuously closed or the vehicle is stopped, ensuring consistent exhaust gas temperature management.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If PID control is reset when exhaust brake valve is closed during traveling automatic regeneration, then the control system responds to current conditions, but the integral control term is lost and regeneration temperature stability deteriorates
Solution Approach 1:
The control system performs preliminary action by continuing to integrate the control term even when the exhaust brake valve is closed, rather than resetting it. This maintains the accumulated integral control term in memory, ensuring that when the valve opens, the integration continues from where it left off, thereby maintaining temperature stability without losing control history.
Solution Approach 2:
The useful action of integrating the control term continues uninterrupted even when the exhaust brake valve is closed. The system maintains continuous integration by using the accumulated integral control term as the initial operation amount when the valve opens, ensuring seamless continuation of the regeneration process without resetting the integration history.
2Loss of energy
If exhaust pipe injection is stopped when exhaust brake valve is closed, then fuel consumption is reduced, but regeneration temperature drops and regeneration efficiency decreases
Solution Approach 1:
The control system uses feedback by continuously monitoring the exhaust brake valve state and adjusting the injection amount accordingly. When the valve is closed, the system reduces injection to save fuel while maintaining the integral control term, ensuring that when the valve opens, the system can quickly restore optimal regeneration temperature without wasting fuel during the closed period.
Solution Approach 2:
The system dynamically adjusts the exhaust pipe injection amount based on the real-time state of the exhaust brake valve. The injection amount is calculated using the accumulated integral control term, allowing the system to optimize fuel consumption when the valve is closed while maintaining the capability to quickly respond and restore regeneration efficiency when the valve opens.
3Stability of the object's composition
If PID control is continuously calculated during frequent brake valve operations, then regeneration temperature is maintained, but calculation complexity increases
Solution Approach 1:
The control system performs preliminary action by accumulating the integral control term in advance during brake valve closure periods. This preliminary accumulation ensures that when the valve opens, the system already has the necessary integrated value to maintain temperature stability, avoiding the need for complex real-time calculations during the critical opening moment.
Solution Approach 2:
The useful action of integrating the control term continues uninterrupted during frequent brake valve operations. By maintaining continuous integration and using the accumulated integral control term as the initial operation amount when the valve opens, the system maintains regeneration temperature stability without requiring complex recalculations, thus reducing overall control complexity.
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 allows for precise control of exhaust pipe injection, maintaining target regeneration temperatures and improving regeneration efficiency and injector durability by preventing integral term resets during frequent brake valve operations.
Implementation Method 1
regeneration is performed by oxidizing, as appropriate, and removing the collected and deposited PM
Implementation Method 2
removing the PM collected on the CSF by burning with such high-temperature exhaust gas
Implementation Method 3
a DOC (Diesel Oxidation Catalyst) constituted by an active catalyst that oxidizes the unburned fuel
Implementation Method 4
a DOC (Diesel Oxidation Catalyst) constituted by an active catalyst that oxidizes the unburned fuel
Implementation Method 5
ammonia is generated by the heat of the exhaust gas
Implementation Method 6
NO x is reduced and decreased on the SCR catalyst by the ammonia
Data Source
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AI summary
Provided is an exhaust gas purification system in which exhaust pipe injection by PID control can be accurately controlled in traveling automatic regeneration even with repeated acceleration and deceleration or even when an exhaust brake valve is closed. A DPD 25 is connected to an exhaust pipe 20 of a diesel engine 10, an exhaust gas temperature during automatic regeneration of the DPD 25 is detected, and the difference between the detected exhaust gas temperature and a target regeneration temperature is determined. In a case where an exhaust pipe injection amount is PID controlled based on this difference, when an exhaust brake valve 24 is closed during traveling automatic regeneration, the exhaust pipe injection is stopped and calculation of an integral control term by the PID control is continued as long as the exhaust valve brake valve 24 is closed, and when the exhaust brake valve 24 is opened, the integral control term that has been continuously calculated is taken as an initial operation amount.