Diesel Engine DPF Regeneration Control via Intake Throttling
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Solution Overview
Problem
Conventional diesel engines face excessive PM accumulation in the DPF due to limited intake throttling in air intake amount feedback control, leading to postponed DPF regeneration and potential DPF exchange requirements, especially in light load and low exhaust gas temperature operating states.
Innovation Solution
A diesel engine system that includes a DOC, DPF, PM accumulation estimating device, control unit, DPF regenerating device, DOC inlet exhaust gas temperature detector, intake throttle device, and load detector, which initiates DPF regeneration by mixing unburned fuel into exhaust gas when PM accumulation reaches a threshold, and switches between air intake amount feedback control and exhaust gas temperature feedback control to ensure the DOC inlet exhaust gas temperature reaches activation temperature for efficient regeneration.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If air intake amount feedback control is used with limited intake throttling, then engine stability is maintained, but DOC inlet exhaust gas temperature does not reach activation temperature and DPF regeneration is postponed
Solution Approach 1:
The control system dynamically switches between air intake amount feedback control and exhaust gas temperature feedback control based on operating conditions. When exhaust gas temperature is low and PM accumulation reaches threshold, the system transitions to temperature feedback control with increased intake throttling target values to rapidly raise temperature and initiate regeneration, resolving the contradiction between maintaining stability and achieving temperature targets.
Solution Approach 2:
The system changes the target value parameter for intake throttling from a fixed air intake amount to a higher value optimized for temperature increase when in exhaust gas temperature feedback control mode. This parameter change enables the intake throttling amount to be sufficiently large to raise exhaust gas temperature to DOC activation temperature, overcoming the limitation of conventional fixed target values.
2Temperature
If intake throttling amount is increased to raise exhaust gas temperature, then DPF regeneration is accelerated, but engine rotation stability deteriorates
Solution Approach 1:
The system dynamically adjusts the intake throttling target value based on the control mode. In exhaust gas temperature feedback control, the target value is set higher to enable rapid temperature rise for regeneration. In air intake amount feedback control, the target value is lower to maintain engine stability. This dynamic adjustment resolves the contradiction by adapting throttling magnitude to operational context.
Solution Approach 2:
The system uses exhaust gas temperature feedback to determine when to switch to high-throttling mode for regeneration. The feedback mechanism monitors temperature and PM accumulation, triggering appropriate control mode transitions that balance temperature rise requirements with engine stability considerations.
3Loss of time
If exhaust gas temperature feedback control is used with high intake throttling, then DPF regeneration is initiated quickly, but engine load response becomes sluggish
Solution Approach 1:
The control mode dynamically adapts to operational requirements. Exhaust gas temperature feedback control with high intake throttling target values is activated only when temperature is low and regeneration is needed, enabling quick regeneration initiation. The system switches between modes based on real-time conditions, optimizing both regeneration speed and load response characteristics for different operating scenarios.
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 prevents excessive PM accumulation in the DPF, allows for early and efficient DPF regeneration, stabilizes engine rotation, and ensures swift start-up of regeneration processes by adjusting intake throttling based on load and temperature feedback controls.
Implementation Method 1
unburned fuel is mixed into exhaust gas 10 in the DPF regenerating processing by the DPF regenerating device 5 under control of the control unit 4 as illustrated in FIG. 1, temperature of exhaust gas 10 rises by catalytic combustion at the DOC 1 of the unburned fuel
Implementation Method 2
PM accumulated on the DPF 2 is burned and removed and the DPF 2 is regenerated
Data Source
AI summary
The present invention provides a diesel engine capable of preventing a PM accumulation amount from increasing excessively. If DOC inlet exhaust gas temperature (“IEGT”) does not reach a predetermined value T0, a control unit carries out air intake amount feedback control (“AIAFC”), and a target value of intake throttling is set to a predetermined air intake amount. If the DPF regenerating processing is not started even if elapsed time reaches a predetermined value t after AIAFC is started in a state where the DOC IEGT does not reach the predetermined value T0, the control unit changes AIAFC to exhaust gas temperature feedback control (“EGTFC”). In EGTFC, the control unit changes a target value of intake throttling to a predetermined DOC IEGT T0. If application of a load exceeding a predetermined amount is detected before the DOC IEGT reaches the predetermined value T0, the control unit returns EGTFC to AIAFC.