Engine PM Sensor Control for Dead Zone Elimination
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Solution Overview
Problem
Conventional particulate matter sensors in internal combustion engines face challenges in detecting PM changes immediately after PM reset due to high power consumption and a 'dead zone' where sensor output is close to zero, leading to delayed detection of increased PM levels, especially when the PM filter becomes defective.
Innovation Solution
A control device for internal combustion engines that includes a particulate matter sensor with elimination means, judgment means to determine if PM is below a reference amount, and control means to terminate the elimination process when the PM is judged to be below this amount, allowing immediate sensor output changes and reducing power consumption by optimizing the elimination process duration based on engine operating status and temperature.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the heater operates for a predetermined period to eliminate PM completely, then the PM accumulation is reset effectively, but the power consumption increases significantly
Solution Approach 1:
The heater operates only until the PM amount reaches a predetermined threshold level rather than eliminating all PM completely. This partial elimination is sufficient to restore sensor functionality while consuming less power than complete elimination would require.
Solution Approach 2:
The control device continuously monitors the sensor output and detects when PM accumulation reaches the threshold level. Based on this feedback, the control device activates the heater only when needed and terminates heating when the threshold is reached, optimizing power consumption while ensuring reliable PM reset.
2Reliability
If the heater eliminates PM virtually completely, then the sensor is reset to initial state, but the sensor output remains close to zero for a certain period
Solution Approach 1:
Instead of eliminating PM completely, the heater stops operation when PM accumulation reaches a predetermined threshold. This leaves a small amount of PM remaining on the sensor, which is sufficient to maintain electrical conduction and generate valid sensor output signals immediately after reset.
Solution Approach 2:
The control device predicts when PM accumulation will reach the threshold level based on sensor output trends and operating conditions. The heater is activated in advance to prevent the sensor from entering the dead zone state, ensuring continuous monitoring capability.
3Device complexity
If the PM reset is performed for a fixed duration, then the control logic is simple, but the power consumption varies with different PM accumulation levels
Solution Approach 1:
The control device monitors the sensor output and activates the heater based on feedback regarding PM accumulation levels. The heating process continues until the sensor output indicates that PM has reached the predetermined threshold, ensuring adaptive power consumption matched to actual PM levels.
Solution Approach 2:
The control device adjusts the heater operation parameters (activation timing, duration) based on the detected PM accumulation level. When PM accumulation is high, the heater operates longer; when PM is already low, the heater operates briefly or not at all, optimizing power consumption according to actual conditions.
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
Enables continuous PM detection post-reset, reduces power consumption, and minimizes the 'dead zone' by terminating the elimination process when the PM is at a level that allows electrical conduction, ensuring timely detection of PM changes and extending sensor functionality.
Implementation Method 1
elimination means for burning and eliminating particulate matter attached to the particulate matter sensor
Implementation Method 2
When the sensor comes into contact with the exhaust gas so that the PM in the exhaust gas is accumulated between the electrodes, electrical conductivity between the electrodes changes in accordance with the amount of accumulated PM
Data Source
AI summary
An internal combustion engine control device having a particulate matter sensor which has a pair of electrodes disposed at a distance from each other and measures the amount of particulate matter in a gaseous body, and elimination means for burning and eliminating particulate matter attached to the particulate matter sensor. The control device performs a particulate matter elimination process to judge whether the amount of particulate matter attached to the particulate matter sensor is smaller than a reference particulate matter amount that is predefined as the minimum amount of remaining particulate matter required to bring the pair of electrodes into electrical conduction at one or more spots. When the amount of particulate matter is judged to be smaller than the reference particulate matter amount, the control device causes the elimination means to terminate the particulate matter elimination process.