Particulate Matter Sensor Voltage Control for Exhaust Detection
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Solution Overview
Problem
Existing particulate matter (PM) sensors for internal combustion engines face challenges in balancing detection sequence time and heater power consumption, with long detection times for low PM discharge rates and frequent resets leading to high power consumption during high discharge rates.
Innovation Solution
The apparatus adjusts the voltage applied across electrodes based on PM discharge amount, engine load fluctuations, and average operating time to optimize deposition rate and reduce power consumption, using a sensor system with voltage adjusting means and discharge amount index acquisition.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of time
If the voltage applied across the electrodes is increased to speed up particulate matter deposition and shorten detection time, then the detection sequence time is reduced, but the heater power consumption increases due to frequent resets
Solution Approach 1:
The patent applies dynamic voltage adjustment where the voltage across the electrodes is not fixed but varies based on detected PM concentration levels. When PM concentration is low, higher voltage is applied to accelerate deposition and reduce dead zone time. When PM concentration is high, lower voltage is applied to prevent excessive deposition that would trigger frequent heater resets. This dynamic adjustment resolves the contradiction by adapting the voltage level to current operating conditions.
Solution Approach 2:
The patent changes the voltage parameter based on PM discharge amount detection. By monitoring PM concentration and adjusting the voltage parameter accordingly, the system optimizes the balance between detection speed and power consumption. The voltage parameter is increased when PM levels are low to shorten detection time, and decreased when PM levels are high to reduce reset frequency and power consumption.
2Use of energy by moving object
If the voltage applied across the electrodes is decreased to reduce heater power consumption, then power consumption is limited, but the detection sequence time increases due to slower particulate matter deposition
Solution Approach 1:
The system dynamically adjusts voltage based on real-time PM concentration feedback. When PM concentration is detected to be low, the voltage is automatically increased to maintain fast deposition rates and short detection times. When PM concentration is high, voltage is reduced to prevent excessive deposition. This dynamic response ensures optimal performance across varying operating conditions without manual intervention.
Solution Approach 2:
The patent implements a feedback control mechanism where the detected PM concentration level feeds back to the voltage control system. This feedback loop enables the system to automatically adjust voltage to maintain optimal detection performance. The feedback ensures that voltage is increased when PM levels are low (to maintain fast detection) and decreased when PM levels are high (to reduce power consumption and reset frequency).
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 shortens detection times during low PM discharge and reduces heater power consumption during high discharge rates, ensuring accurate and timely particulate matter detection while managing energy usage effectively.
Implementation Method 1
voltage is applied across the electrodes to thereby generate an electric field, so that the charged particulate matter in an exhaust gas is attracted by the electric field for trapping
Implementation Method 2
the heater is energized and the particulate matter deposited is thereby burned and removed
Data Source
AI summary
An object of the present invention is to provide a particulate matter detecting apparatus for an internal combustion engine that can maintain an appropriate balance between reduction in time required for one detecting sequence and limiting of power consumption of a heater for sensor reset.The particulate matter detecting apparatus for an internal combustion engine includes: a sensor disposed at an exhaust passage of an internal combustion engine, the sensor including a pair of electrodes for trapping particulate matter; voltage applying means for applying voltage across the electrodes; discharge amount index acquiring means for acquiring a predetermined index associated with a discharge amount of the particulate matter; and voltage adjusting means for adjusting the voltage to be applied across the electrodes based on the index acquired by the discharge amount index acquiring means such that the voltage is lower when the discharge amount is large than when the discharge amount is small.