Sheathed Element Glow Plug Having a Combustion Chamber Pressure Sensor

Abstract

A sheathed element glow plug includes an integrated combustion chamber pressure sensor for a self-igniting internal combustion engine for measuring combustion chamber pressures, in particular for combustion chamber signal-based engine control. The sheathed element glow plug has a heating element and a glow plug housing, as well as a glow plug axis. The glow plug housing has a receptacle area for receiving the heating element, a housing body, and at least one flexibility area situated between the housing body and the receptacle area. At least one force measuring element is installed in the glow plug housing.

Description

FIELD OF THE INVENTION[0001]The present invention relates to a sheathed element glow plug having an integrated combustion chamber pressure sensor. Sheathed element glow plugs of this type are used in particular in self-igniting internal combustion engines for measuring a combustion chamber pressure.BACKGROUND INFORMATION[0002]As a result of increasingly strict exhaust gas legislation, in particular for diesel engines, the demands for reduced emissions of harmful substances by self-igniting internal combustion engines are becoming stricter. Today's engine management systems are expected to ensure low emissions of harmful substances and low fuel consumption, in addition to having a long service life at the same time. Combustion may be optimized in the combustion chamber of a diesel engine in particular by using regulated injection of fuel. Regulated injection may be controlled in particular by electronic engine control units, which are already routinely used in today's motor vehicles....

AI Technical Summary

Benefits of technology

[0005]Therefore, according to example embodiments of the present invention, a sheathed element glow plug for a self-igniting internal combustion engine has an integrated combustion chamber pressure sensor and which avoids the disadvantages of the devices as described above. In particular, the sheathed element glow plug permits the fluctuations in the sensor pre-tension, caused by temperature, and the mechanical friction of individual components of the sheathed element glow plug during operation, which, as described above, may result in problems in certain c

Problems solved by technology

However, for using such devices, a separate bore hole must be provided in the cylinder head wall, which is not always feasible for reasons of space and it also means additional assembly effort, including additional operations.

In particular, in today's four-valve internal combustion engines, making additional bore holes is hardly implementable in practice due to the extremely tight space constraints.

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.

The device described in German Published Patent Application No. 196 80 912 has, however, numerous practical disadvantages.

This in turn may result in friction and thus in a corruption of the combustion chamber pressure signal; in particular there is the additional risk of soot deposition on the guide between the stationary part (i.e., the part fixedly connected to the cylinder head) and the moving part of the sheathed element glow plug.

Another disadvantage of the device described in German Published Patent Application No. 196 80 912 is tha

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