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.

1 - 11 . (canceled) 
   
   
       12 . A sheathed element glow plug for a compression-ignition internal combustion engine, comprising:
 a first module containing a heating element and a glow plug housing; and   a pressure measuring module, a side of the pressure measuring module which faces away from the heating element being adjacent to the first module, at least one force measuring element being integrated into the pressure measuring module, the at least one force measuring element being adapted to generate an electrical signal as a function of a force, the at least one force measuring element being 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.   
   
   
       13 . The sheathed element glow plug as recited in  claim 12 , wherein the at least one force measuring element includes at least one of a piezoelectric force measuring element, a piezoresistive force measuring element, a capacitive force measuring element, an inductive force measuring element, and a force measuring element having strain gages. 
   
   
       14 . The sheathed element glow plug as recited in  claim 12 , wherein the glow plug housing and the pressure measuring module are one of connected by an integral joint, or friction-locked to each other. 
   
   
       15 . The sheathed element glow plug as recited in  claim 12 , further comprising:
 at least one additional force transmission element, a force being transmittable from the heating element to the at least one force measuring element with the aid of the at least one force transmission element.   
   
   
       16 . The sheathed element glow plug as recited in  claim 12 , wherein the at least one force transmission element has a force transmission ram. 
   
   
       17 . The sheathed element glow plug as recited in  claim 15 , wherein the at least one force measuring element has at least one actuator surface extending perpendicularly to an axis of the sheathed element glow plug, the at least one force measuring element is radially attached to a housing of the pressure measuring module, and a force being exertable in an axial direction directly or indirectly onto the at least one actuator surface using the at least one force transmission element. 
   
   
       18 . The sheathed element glow plug as recited in  claim 15 , further comprising:
 at least one diaphragm between the at least one force transmission element and the at least one force measuring element, the at least one diaphragm being preferably integrated into the at least one force measuring element.   
   
   
       19 . The sheathed element glow plug as recited in  claim 15 , further comprising:
 at least one vibration damping element installed in the glow plug housing, the at least one vibration damping element filling, one of fully or partially, at least one cavity between the at least one force transmission element and the glow plug housing.   
   
   
       20 . The sheathed element glow plug as recited in  claim 19 , wherein the at least one vibration damping element has at least one resin. 
   
   
       21 . The sheathed element glow plug as recited in  claim 12 , further comprising:
 at least one separating wall between the glow plug housing and the pressure measuring module, the at least one separating wall having at least one force transmission opening.   
   
   
       22 . A method for manufacturing a sheathed element glow plug for a compression-ignition internal combustion engine, comprising:
 assembling a first module having a heating element and a glow plug housing, the heating element being connected to the glow plug housing;   assembling a pressure measuring module having at least one force measuring element, the at least one force measuring element adapted to generate an electrical signal as a function of a force; and   connecting the pressure measuring module to the first module so that a force is transmittable to the at least one force measuring element via the heating element.