Gasoline Particulate Filter Soot Level Control
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Solution Overview
Problem
Gasoline particulate filters (GPFs) with higher filtration features become less efficient when clean, leading to reduced soot capture rates and increased exhaust backpressure, which affects engine power and fuel efficiency, and the optimal soot level varies with operating conditions, causing inefficiencies in emissions control.
Innovation Solution
A method to actively maintain a target soot level on the GPF by adjusting fuel injection timing and pressure, using a lower filtration capability GPF, and controlling ash levels to optimize soot capture and reduce backpressure, by determining the target soot level based on engine temperature, load, and operating conditions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If a higher filtration capability GPF with denser mesh is used, then emissions quality is improved, but exhaust backpressure increases and engine power decreases
Solution Approach 1:
The patent applies dynamics by making the filter's effective filtration capability variable through controlled soot accumulation. The filter transitions from a static high-mesh-density design to a dynamic system where soot loading modulates the actual filtration behavior, allowing the system to adapt between high capture efficiency (when soot-loaded) and low backpressure (when clean).
Solution Approach 2:
The invention changes the operational parameters of the filter by controlling the soot level on the filter media. By adjusting engine operating parameters (fuel injection timing, air-fuel ratio) to maintain optimal soot accumulation, the system effectively changes the filter's capture rate and backpressure characteristics without physically altering the filter structure.
2Object-affected harmful factors
If a higher filtration capability GPF with denser mesh is used, then soot capture rate is improved, but exhaust backpressure increases
Solution Approach 1:
The patent converts the harmful effect of soot accumulation (which normally increases backpressure and reduces efficiency) into a beneficial function. By deliberately allowing controlled soot accumulation on a lower mesh density filter, the system uses the soot layer to enhance particle capture while the underlying lower-density structure prevents excessive backpressure buildup.
3Productivity
If the filter is regenerated to remove all soot, then filtration efficiency is maximized, but emissions control during cold-start deteriorates
Solution Approach 1:
The system performs preliminary action by maintaining a residual soot level on the filter before cold-start conditions occur. This pre-existing soot layer ensures that when cold-start conditions arise, the filter is already in an optimal state for particle capture, eliminating the need for rapid soot accumulation during the critical cold-start period.
4Object-affected harmful factors
If a higher mesh density GPF is used, then emissions quality is improved, but device cost increases
Solution Approach 1:
The patent employs a lower mesh density filter that is cheaper to manufacture, and compensates for its lower inherent filtration capability by using controlled soot accumulation to achieve the required emissions performance. This approach replaces an expensive permanent high-performance filter with a cheaper filter plus a controlled operational strategy.
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 improves the operational efficiency of the GPF, reduces exhaust backpressure, and enhances engine power and fuel efficiency while maintaining emissions quality, using less expensive filter components.
Implementation Method 1
a gasoline particulate filter (GPF) with a lower than threshold filtration mesh density, coupled to the exhaust passage
Implementation Method 2
A soot level at the GPF may be estimated based on inputs from one or more pressure sensors coupled upstream and/or downstream of the GPF
Data Source
AI summary
Methods and systems are provided for optimal operation of a gasoline particulate filter coupled to an engine exhaust system. Based on engine operating conditions, a target soot level on the GPF may be determined, and one or more engine operating parameters may be adjusted to maintain the actual GPF soot level at the target level. In one example, if the actual GPF soot level is lower than the target level, one or more of a fuel injection timing and a fuel rail pressure may be adjusted to increase soot generation, and if the actual GPF soot level is higher than the target level, the GPF may be regenerated until the actual soot level reaches the target level.