Freezing Diagnosis for Differential Pressure Sensor Pipes
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Solution Overview
Problem
Existing freezing diagnosing devices for exhaust systems struggle to accurately detect the freezing state of differential pressure sensor pipes in low-temperature environments, leading to errors in soot accumulation estimation and self-diagnosis of particulate matter filters due to condensation and freezing of water vapor.
Innovation Solution
A freezing diagnosing device equipped with an ambient temperature sensor, liquid temperature sensor, and a freezing determination unit that estimates heat transfer and dissipation to determine the freezing state and release state of the pipe, preventing control execution until the pipe is thawed.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If differential pressure detection is performed in low-temperature environments, then soot accumulation estimation and filter diagnosis can be conducted, but water vapor condensation and freezing in the pipe will occur causing detection errors
Solution Approach 1:
The system performs preliminary freezing determination by comparing ambient temperature and liquid temperature against predetermined thresholds before executing differential pressure-based soot accumulation estimation. This preliminary check prevents detection errors by identifying freezing conditions in advance, ensuring reliable measurements only when temperatures are above freezing thresholds.
Solution Approach 2:
Temperature sensors act as intermediary elements that monitor ambient and liquid temperatures to predict freezing conditions. These temperature measurements serve as intermediate indicators that inform the control unit whether differential pressure detection should proceed, indirectly protecting against freezing-related detection errors without directly preventing condensation.
2Device complexity
If freezing determination is based only on ambient temperature, then the system remains simple, but it cannot accurately detect freezing state when exhaust heat keeps the pipe above freezing
Solution Approach 1:
The system merges multiple temperature parameters (ambient temperature and liquid temperature) into a comprehensive freezing determination process. By combining these temperature inputs with predetermined thresholds, the system achieves accurate freezing state detection that accounts for exhaust heat effects, while maintaining relative simplicity through threshold-based comparison logic.
Solution Approach 2:
The temperature sensors serve multiple functions: they monitor both ambient conditions and liquid temperatures, and their readings are used for both freezing determination and informing regeneration control. This multi-functionality allows accurate freezing detection without adding separate dedicated sensors for each parameter.
3Measurement precision
If the system prohibits control execution when freezing is detected, then accurate detection is maintained, but engine control and filter regeneration are delayed
Solution Approach 1:
The system dynamically adjusts control execution based on real-time freezing determination results. When temperatures indicate no freezing risk, differential pressure-based control and regeneration operations proceed normally. When freezing conditions are detected, control is temporarily prohibited. This dynamic adaptation minimizes time loss while maintaining measurement precision.
Solution Approach 2:
The system continuously monitors temperature parameters and uses this feedback to determine whether to permit or prohibit control execution. This feedback loop allows the system to resume operations as soon as temperature conditions improve, minimizing delays while ensuring accurate detection during critical measurement periods.
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
Accurately determines the freezing and thawing states of the pipes, preventing false readings and ensuring accurate differential pressure detection, thereby maintaining proper engine control and filter regeneration operations.
Implementation Method 1
an ambient temperature sensor configured to detect an ambient temperature
Implementation Method 2
a liquid temperature sensor configured to detect a temperature of a liquid held in the engine
Implementation Method 3
water vapor contained in the exhaust gas discharged from the engine can transform into condensed water in a pipe for introducing the exhaust gas to a differential pressure sensor
Implementation Method 4
The condensed water can be frozen in some cases
Implementation Method 5
a transferred heat estimator configured to estimate an amount of heat transferred from the exhaust passage to the pipe
Implementation Method 6
a dissipated heat estimator configured to estimate an amount of heat dissipated from the pipe
Data Source
AI summary
A freezing diagnosing device to be installed in an engine includes an ambient temperature sensor, a liquid temperature sensor, and a freezing determination unit. The ambient temperature sensor detects an ambient temperature. The liquid temperature sensor detects the temperature of a liquid held in the engine. The freezing determination unit determines that a freezing state of a pipe coupled to a pressure sensor in the engine is established when one or both of a first condition and a second condition are satisfied. The first condition is that the ambient temperature detected by the ambient temperature sensor is equal to or less than a first threshold. The second condition is that the temperature of the liquid detected by the liquid temperature sensor is equal to or less than a second threshold.