Sheathed Element Glow Plug Having an Integrated Pressure Measuring Element

Abstract

In combustion chamber signal-based engine control in particular, a reliable and at the same time cost-effective option for detecting a combustion chamber pressure in compression-ignition internal combustion engines is required. A sheathed element glow plug is proposed, which has a glow plug module and a pressure measuring module connected to the glow plug module. The glow plug module has a heating element and a glow plug housing. The pressure measuring module has at least one force measuring element, which is integrated into the pressure measuring module. The at least one force measuring element is designed to generate an electrical signal as a function of a force. In the mounted state of the sheathed element glow plug, the at least one force measuring element is connected to the heating element in such a way that a force is transmittable to the at least one force measuring element via the heating element.

Description

FIELD OF THE INVENTION[0001]The present invention relates to a sheathed element glow plug having an integrated pressure measuring element and a method for manufacturing a sheathed element glow plug of this type. In particular, the present invention relates to a sheathed element glow plug which, in addition to a heating element and a glow plug housing, has a pressure measuring module having at least one force measuring element.BACKGROUND INFORMATION[0002]As a result of increasingly strict legal exhaust gas regulations, in particular for diesel engines, the requirements for reduced emissions of harmful substances by compression-ignition internal combustion engines are becoming stricter. Modern engine management systems should ensure low fuel consumption, while having a long service life.[0003]Combustion in the combustion chamber of a diesel engine may be optimized in particular by using regulated injection of fuel. This regulated injection may be controlled in particular by electronic...

AI Technical Summary

Benefits of technology

[0014]An example sheathed element glow plug according to the present invention has numerous advantages compared to conventional devices. In particular, the use of a separate pressure measuring module and the modular design have the effect that the external dimensions of the at least one force measuring element are no longer limited by the internal space of the glow plug housing. This makes a greater selection of force measuring elements commercially available, which helps reduce production costs and avoid delivery bottlenecks. Occasionally force measuring elements having a higher accuracy, l

Problems solved by technology

However, for using such devices, a separate bore hole must be provided in the cylinder head wall, which means additional assembly effort.

In addition, stand-alone sensors require additional bore holes in the cylinder head of the internal combustion engine, which, in particular in the case of four-valve engines as designed today, raises considerable problems due to the very scarce available space.

Furthermore, in general, systems of this type are relatively expensive and the service life of systems of this type is significantly shorter than that of a typical vehicle, mostly due to the high operating temperatures.

On the other hand, the signal quality of such combustion chamber pressure sensors is strongly dependent on the variation of forces in the entire mechanical complex and usually does not meet the requirements that have been set.

DE 196 80 912 C2 has the disadvantage in particular that the pressure sensor is directly connected to the heating section and is therefore exposed to high thermal stresses and temperature fluctuations.

DE 196 80 912 C2 is complicated because the heating s

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