Diesel Particulate Filter Soot Sensor Efficiency Detection
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Solution Overview
Problem
Current soot sensors in diesel particulate filters (DPFs) are unable to provide continuous measurements of soot concentration, making it unreliable to determine DPF efficiency during real-road running, as they only offer mean values over wide time ranges due to their operational characteristics of alternating soot loading and regeneration phases.
Innovation Solution
A method involving a counter that increments based on soot concentration measurements and response time, allowing for the detection of unsuitable DPF efficiency by setting a borderline value and determining when the next regeneration phase begins, thereby enabling reliable evaluation of DPF efficiency without continuous measurement.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a soot-sensor is used to measure soot concentration at the DPF outlet, then DPF efficiency can be evaluated, but the sensor cannot provide continuous measurement and only returns mean values over wide time ranges
Solution Approach 1:
The patent introduces a counter as an intermediary element that accumulates soot concentration values over time and compares them against threshold values. This counter acts as a mediator between the imperfect soot-sensor measurements and the DPF efficiency determination, enabling reliable efficiency assessment even with non-continuous, mean-value sensor readings. The counter accumulates measurements during soot-loading phases and compares the accumulated value against thresholds to determine whether DPF efficiency is above or below a borderline value.
2Duration of action of stationary object
If the soot-sensor operates with alternating soot loading and regeneration phases, then the sensor can function continuously, but it cannot provide continuous soot concentration measurements for real-road running evaluation
Solution Approach 1:
The patent applies preliminary action by accumulating soot concentration measurements in a counter during the soot-loading phase before regeneration occurs. The counter accumulates values throughout the entire soot-loading phase, so that when regeneration begins, the accumulated value is already available for comparison against threshold values. This allows the system to determine DPF efficiency based on data collected before the regeneration interruption, effectively compensating for the measurement gaps caused by alternating operational phases.
3Reliability
If a counter is introduced to accumulate soot concentration values, then DPF efficiency can be reliably determined, but the system complexity increases
Solution Approach 1:
The patent changes the parameter being monitored from instantaneous soot concentration to accumulated soot concentration represented by a counter value. Instead of trying to process continuous concentration signals, the system transforms the problem by accumulating discrete measurements over time and comparing the accumulated value against threshold parameters. This parameter transformation simplifies the evaluation logic while maintaining reliability, as the counter provides a straightforward numerical representation of total soot exposure that can be directly compared to predefined thresholds.
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 method provides a reliable strategy to assess DPF efficiency, allowing for timely replacement or notification of unsuitable conditions, ensuring compliance with emission regulations and maintaining vehicle performance.
Implementation Method 1
Current in-development soot sensors are conductometric sensors comprising a plurality of electrodes mutually separated on an insulating substrate provided for loading soot. As the soot is loaded on this substrate, an electrical current starts to flow between the electrodes of the soot-sensor and then gradually increases.
Implementation Method 2
When the current exceeds a predetermined threshold, the soot-sensor is subjected to a regeneration phase, during which the accumulated soot is burned off by means of a dedicated heater associated to the substrate
Data Source
AI summary
A method is provided to operate a diesel particulate filter of a Diesel engine equipped with a soot-sensor located in an outlet of the diesel particulate filter, the soot-sensor operating according to a succession of soot loading phases mutually separated by a regeneration phase. The method includes, but is not limited to setting a borderline value of the efficiency of the diesel particulate filter, resetting a value of a counter, during a regeneration phase of the soot-sensor, this value representing a soot loading level of the soot-sensor, iteratively increasing the value of this counter, during a next soot loading phase of the soot-sensor, at least until the value reaches a predetermined threshold value of the counter, and detecting an unsuited efficiency of the diesel particulate filter, if a next regeneration phase of the soot-sensor begins when the value of the counter is below the predetermined threshold value of the counter.