Exhaust Purification System Air-Based Control Sequence
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Solution Overview
Problem
Existing exhaust purification systems face challenges in effectively reducing fuel consumption during NOx purge operations, as injection-based control is often initiated before the intake air amount is reduced to the target level, leading to inefficient fuel use.
Innovation Solution
An exhaust purification system that includes a NOx catalyst, air flow-rate acquisition means, and a controller for performing air-based and injection-based controls in a coordinated manner, ensuring that air-based control reduces the air flow-rate to a target level before initiating injection-based control for catalyst regeneration, thereby preventing premature injection-based control and optimizing fuel consumption.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If injection-based control is started before air-based control reduces intake air amount to target level, then catalyst regeneration can begin earlier, but fuel consumption deteriorates
Solution Approach 1:
The system performs air-based control first to reduce the intake air amount to the target level before initiating injection-based control. This preliminary action ensures that the exhaust air-fuel ratio reaches the appropriate state before adding extra fuel for catalyst regeneration, preventing premature injection and optimizing fuel consumption while maintaining regeneration effectiveness.
2Manufacturing precision
If air-based control and injection-based control are performed in combination, then exhaust lambda can be decreased to target lambda, but control coordination becomes complex
Solution Approach 1:
The control process is segmented into two distinct phases: air-based control phase (reducing intake air to target level) and injection-based control phase (increasing fuel injection for regeneration). By dividing the combined control into sequential segments with clear transition criteria, the system achieves precise exhaust lambda control while managing control complexity through structured phase separation.
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 suppresses fuel consumption deterioration by ensuring that air-based control is fully implemented before starting injection-based control, thereby optimizing the NOx purge process and maintaining efficient fuel use.
Implementation Method 1
When the exhaust is in a lean atmosphere, the NOx-occlusion-reduction-type catalyst occludes NOx contained in the exhaust
Implementation Method 2
when the exhaust is in a rich atmosphere, the NOx-occlusion-reduction-type catalyst detoxifies and releases the occluded NOx with hydrocarbon contained in the exhaust by reduction and purification
Data Source
AI summary
An exhaust purification system including a NOx catalyst 32 provided in an exhaust passage of an internal combustion engine 10 and purifying NOx in exhaust; a MAF sensor 40 for acquiring an air flow-rate of the internal-combustion engine 10; a control unit 60, 70 that execute catalyst regeneration treatment of recovering a NOx purification ability of the NOx catalyst 32 by performing, in combination, air-based control of reducing air flow-rate of the internal-combustion engine 10 to a predetermined target air flow-rate and injection-based control of increasing a fuel injection amount, wherein, in a case of executing the catalyst regeneration treatment, the control unit 60, 70 starts with the air-based control and starts the injection-based control when the air flow-rate acquired by the MAF sensor 40 is reduced to the target air flow-rate.