Air Mass Sensor Pressure-Equalizing Chamber for Turbocharger Vibration
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Solution Overview
Problem
Existing air mass sensors are susceptible to vibration excitations from exhaust turbochargers, leading to significant deviations in air mass flow measurements due to high-frequency pressure pulsations, which can impair engine operation.
Innovation Solution
The air mass sensor design incorporates a flow channel and electronics chamber connected via an opening to form a pressure equalization volume, with sensor electronics partially or fully encapsulated in a potting compound, and features openings with specific dimensions and configurations to reduce vibration excitations.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If the flow channel is designed to conduct air mass flow through the housing, then the air mass flow measurement function is achieved, but vibration excitations from turbochargers cause significant deviations in measurement results
Solution Approach 1:
The electronics chamber acts as an intermediary pressure equalization volume between the flow channel and the external environment. It absorbs high-frequency pressure pulsations from turbochargers through its volume, preventing these vibrations from directly affecting the measurement elements in the flow channel, thus improving measurement accuracy while maintaining the air mass flow measurement function
Solution Approach 2:
The patent changes the physical parameters of the flow channel by introducing a pressure equalization volume (the electronics chamber) with specific volume requirements (more than 0.5 cm³ and less than 20 cm³). This parameter change modifies the vibrational characteristics of the flow channel, reducing its sensitivity to turbocharger-induced vibrations while preserving the measurement capability
2Reliability
If the electronics chamber is connected to the flow channel via an opening for pressure equalization, then vibration responses are reduced, but the opening dimensions must be precisely controlled
Solution Approach 1:
The opening is designed as a gap or thin-walled structure that provides pressure equalization functionality. The gap configuration (with width at least five times its height) acts as a flexible pressure equalization path that is tolerant to manufacturing variations, allowing the electronics chamber to function as a pressure equalization volume without requiring precise opening dimensions
3Object-affected harmful factors
If sensor electronics are encapsulated in potting compound to protect from environmental influences, then protection from air mass flow is achieved, but access to sensor components is restricted
Solution Approach 1:
The sensor electronics are encapsulated in a potting compound that creates a protective copy or surrogate environment around the electronic components. This encapsulation protects the electronics from the air mass flow and environmental influences while maintaining the functional integrity of the sensor, as the potting compound serves as a protective barrier that does not interfere with the sensing function
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 design minimizes vibration responses caused by high-frequency pressure pulsations, ensuring reliable air mass flow measurements even at critical excitation frequencies, thereby improving sensor robustness and measurement accuracy.
Implementation Method 1
the electronics chamber forming a pressure equalization volume for the flow channel
Implementation Method 2
This allows, in particular, the amplitude of vibration excitations resulting from high-frequency pressure pulsations of turbochargers to be reduced
Data Source
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AI summary
The invention relates to an air mass sensor (2) for determining an air mass flow (L), comprising a housing (4) and sensor electronics (6), the sensor electronics (6) being at least partly located in an electronics chamber (8) of the housing (4), the housing (4) having a duct (14) for guiding an air mass flow (L) to be measured through the housing (4), the duct (14) and the electronics chamber (8) being connected to one another via an opening (26), the electronics chamber (8) forming a pressure compensation volume for the duct (14).