Glow Plug Pressure Sensor Isolation via Sleeve Routing
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing pressure-measuring glow plugs for internal combustion engines face interference between the glow plug and pressure sensor due to the routing of the glow current line within the pressure sensor, affecting the accuracy of pressure measurements.
Innovation Solution
The glow current line is routed outside the pressure sensor, using a sleeve-shaped pressure transmission element with a radial recess to guide the line past the sensor, and connected to a high-current contact outside the pressure measuring unit, avoiding interference and allowing for adjustable mechanical preload of the pressure sensor.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If the glow current line is routed through the pressure sensor, then the electrical connection is simplified, but the pressure measurement accuracy deteriorates due to interference from the glow plug contact
Solution Approach 1:
The patent divides the electrical connection path into separate segments: the glow current line is routed through a dedicated bore in the support element, completely separate from the pressure sensor's electrical path. This segmentation eliminates interference between the high-current glow plug circuit and the low-current pressure sensor circuit, resolving the contradiction between connection simplicity and measurement accuracy.
Solution Approach 2:
The glow current line is extracted from the pressure sensor assembly and routed through an alternative path via the support element bore. This extraction removes the source of electrical interference from the pressure measurement zone, allowing accurate pressure sensing while maintaining electrical connectivity for the glow plug function.
2Stability of the object's composition
If the clamping sleeve is tightly fitted to the housing, then the assembly is mechanically stable, but the pressure sensor accuracy deteriorates due to friction affecting the pressure transmission
Solution Approach 1:
The patent introduces a radial recess in the pressure transmission element as an intermediary feature between the clamping sleeve and housing. This recess creates a controlled clearance that eliminates frictional interference on the pressure sensor while maintaining mechanical stability through the clamping sleeve's positioning function. The intermediary clearance zone decouples the mechanical stability function from the pressure transmission function.
Solution Approach 2:
The radial recess creates a localized clearance zone specifically at the interface between the clamping sleeve and housing, while other portions of the assembly maintain tight fits for stability. This local modification to the geometry allows frictionless pressure transmission in the critical zone while preserving overall mechanical stability elsewhere in the assembly.
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 enhances the accuracy of pressure measurements by isolating the glow plug contact from the pressure sensor and enabling adjustable mechanical preload, reducing friction and maintaining measurement precision.
Implementation Method 1
The pressure sensor is prestressed with the spring force of a flexible membrane
Implementation Method 2
The pressure sensor is prestressed with the spring force of a flexible membrane
Data Source
Figure 1
Figure 2
Figure 3~4
AI summary
The invention relates to a pressure measuring glow plug comprising a housing (13, 14) in which a tubular heating element (21) for igniting a combustion mixture of an internal combustion engine and a pressure measuring unit (30) for detecting the pressure in the combustion chamber of the internal combustion engine are arranged. The tubular heating element (21) has a glow current contact (23) for an electric heating element (22). A pressure transfer element (50) is secured to the end of the tubular heating element (21) facing away from the combustion chamber, and transfers the combustion chamber pressure, which acts on the tubular heating element (21), to the pressure measuring unit (30). The pressure transfer element (50) is designed in a sleeve-like manner and forms a receiving chamber (51) for the glow current contact (23) of the heating element (22) on the tubular heating element side.