Exhaust Pressure Sensor Temperature Control
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Solution Overview
Problem
Current pressure sensors in internal combustion engine exhaust systems lack sufficient accuracy to reliably identify a defective diesel particulate filter due to low flow resistance and small differential pressure differences, which are exacerbated by temperature influences.
Innovation Solution
A pressure sensor with a temperature control device that maintains a constant temperature level using a tempering fluid or electric heating/cooling, combined with temperature-compensating electronics to minimize temperature gradients and enhance measurement accuracy.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If a pressure sensor is used in an exhaust system with low flow resistance, then the device complexity is reduced, but the measurement precision deteriorates due to insufficient accuracy to detect small differential pressure differences
Solution Approach 1:
The patent changes the temperature parameter of the pressure sensor by introducing a temperature control device that heats the sensor to a constant temperature level. This parameter change compensates for temperature-induced measurement errors, enabling accurate detection of small differential pressure differences (e.g., 4-5 hPa) in low flow resistance exhaust systems without increasing device complexity
Solution Approach 2:
The patent replaces mechanical/thermal stabilization methods with an active temperature control device that uses heating elements and temperature sensors to maintain a constant temperature level. This substitution enables precise measurement of small pressure differences by eliminating temperature gradients that would otherwise affect measurement accuracy
2Measurement precision
If temperature control is implemented to improve measurement accuracy, then the measurement precision is improved, but the use of energy increases due to heating and cooling requirements
Solution Approach 1:
The temperature control device implements a feedback mechanism using temperature sensors to monitor the temperature level of the pressure sensor and adjust the heating elements accordingly. This feedback control maintains a constant temperature level, reducing energy consumption compared to continuous heating, while ensuring measurement accuracy is maintained
Solution Approach 2:
The patent optimizes the temperature parameter by maintaining the sensor at a constant elevated temperature rather than allowing it to fluctuate with ambient conditions. This parameter stabilization reduces the energy required for temperature control while improving measurement precision by eliminating temperature-induced measurement errors
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 highly accurate pressure and differential pressure measurements by reducing temperature-related inaccuracies, allowing for effective monitoring and control of diesel particulate filters in exhaust systems.
Implementation Method 1
a temperature control fluid is passed through the sensor housing, with the temperature in the sensor housing being kept at a constant temperature level by controlled heating, preferably by electrically operated heating of the temperature control fluid
Implementation Method 2
a temperature control fluid is passed through the sensor housing
Implementation Method 3
The sensor function is realized by a membrane, which is heated to a temperature above the ambient temperature by a heating means
Data Source
Figure 1
Figure 2
AI summary
The pressure sensor (11) has a sensor housing (13) with a pressure measuring cell arranged in the sensor housing, where the pressure measuring cell is provided with sensor electronics and is connected with a measuring medium line, particularly an exhaust measuring line (9,10). A tempering device (14) is provided for the pressure sensor for increasing the measurement accuracy. The sensor electronics of the pressure sensor is designed as an application-specific integrated semiconductor circuit. An independent claim is included for a method for actuating a pressure sensor.