Engine Exhaust Throttle Control for DPF Regeneration
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Solution Overview
Problem
Conventional engines face challenges in promoting DPF regeneration due to abrupt drops in exhaust temperature caused by the sudden opening of the exhaust throttle device, leading to stagnation of the regeneration process.
Innovation Solution
The engine controls catalyst activation and DPF regeneration processes by setting target exhaust temperatures in specific regions, with the exhaust throttle device's opening degree adjusted accordingly, and unburned fuel is supplied to promote regeneration, ensuring a controlled temperature gradient to prevent stagnation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If the exhaust throttle device abruptly opens during transition from catalyst activation to DPF regeneration, then the back pressure drops, but the exhaust temperature abruptly drops causing stagnation of DPF regeneration
Solution Approach 1:
The exhaust throttle device opening degree is dynamically adjusted based on the current operating phase (catalyst activation vs. DPF regeneration) and temperature feedback, rather than abrupt opening. The control device modulates the throttle opening gradually to maintain temperature while transitioning between operations.
Solution Approach 2:
The system uses exhaust temperature feedback from the temperature sensor to continuously adjust the exhaust throttle device opening degree. The control device monitors temperature and modulates throttle opening to maintain temperature within target ranges during both catalyst activation and DPF regeneration phases.
2Productivity
If the exhaust throttle device is controlled to maintain temperature, then DPF regeneration is promoted, but the control complexity increases
Solution Approach 1:
The control process is segmented into distinct phases (catalyst activation phase and DPF regeneration phase) with different target temperature regions. Each phase has predefined temperature targets and control strategies, simplifying the overall control logic while maintaining effectiveness.
Solution Approach 2:
The control device changes operational parameters (target temperature region, throttle opening degree) based on the current phase. During catalyst activation, a lower target temperature region is used, while during DPF regeneration, a higher target temperature region is targeted, with intermediate regions avoided.
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 prevents stagnation of DPF regeneration by maintaining a controlled temperature gradient, ensuring efficient regeneration and reducing thermal degradation of engine components.
Implementation Method 1
a catalyst (4) housed in the catalyst case (3), the catalyst (4) being on the exhaust upstream side of the exhaust throttle device (8)... unburned fuel supplied into the exhaust (5) is catalytically combusted
Implementation Method 2
an exhaust temperature sensor (9) disposed between the catalyst (4) and the exhaust throttle device (8)
Implementation Method 3
a DPF (12) disposed on the exhaust downstream side of the catalyst case (3)... the DPF (12) having an exhaust inlet (12a) and an exhaust outlet (12b)
Data Source
AI summary
An engine promoting DPF regeneration processing is provided. Catalyst activation processing and thereafter DPF regeneration processing are performed under control of a device. In the catalyst activation processing, a target temperature of exhaust at an exhaust exit of a catalyst is set to be in a first temperature region, and then the opening degree of an exhaust throttle device is controlled. In the DPF regeneration processing, the target temperature is set to be in a second temperature region. A target temperature of the exhaust at an exhaust inlet of a DPF is set to be in a third temperature region. The opening degree of the exhaust throttle device is controlled, and unburned fuel is supplied into the exhaust. The temperature regions are set to be successively higher, and a temperature difference between successive temperature regions is set to be successively lower.