Glow Plug Containing a Combustion Chamber Pressure Sensor

Abstract

The invention relates to a glow plug ( 11 ) comprising a combustion chamber pressure sensor ( 19 ) for an internal combustion engine. Said plug essentially consists of a housing ( 13 ), a glow element ( 17 ) that is located in the housing ( 13 ) and a channel ( 21 ) for measuring the combustion chamber pressure. An inventive heating element, ( 26 ) which is connected to the channel ( 21 ), prevents the clogging of the combustion chamber pressure sensor ( 19 ) that is located at the end of the channel ( 26 ) by coking or combustion residues. The glow plug ( 11 ) comprising a combustion chamber pressure sensor ( 19 ) is preferably used in the automobile industry.

1 - 13 . (canceled) 
   
   
       14 . A glow plug, comprising:
 a combustion chamber pressure sensor;   a housing;   a glow element disposed in the housing;   at least one channel leading to the combustion chamber pressure sensor and used for measuring a combustion chamber pressure, wherein the at least one channel is able to be heated by at least one heating element.   
   
   
       15 . The glow plug as recited in  claim 14 , wherein the at least one channel extends approximately parallel to the glow element along an inner wall of the housing. 
   
   
       16 . The glow plug as recited in  claim 15 , wherein the at least one channel is represented by a profile provided on a sleeve abutting the inner wall of the housing. 
   
   
       17 . The glow plug as recited in  claim 15 , wherein the at least one channel is represented by a smooth-surfaced sleeve abutting a profile provided on the inner wall. 
   
   
       18 . The glow plug as recited in  claim 16 , wherein:
 the sleeve includes an inner ring and an outer ring, and   the heating element is embedded between the inner ring and the outer ring.   
   
   
       19 . The glow plug as recited in  claim 18 , wherein the heating element includes a heating meander that is electrically isolated from the inner ring and the outer ring. 
   
   
       20 . The glow plug as recited in  claim 19 , wherein the heating meander is laminated in between two films using thick-film technology. 
   
   
       21 . The glow plug as recited in  claim 14 , wherein the at least one channel includes a catalytic coating ( 31 ). 
   
   
       22 . The glow plug as recited in  claim 14 , wherein the heating element is operated one of permanently in a first mode and cyclically in a second mode. 
   
   
       23 . The glow plug as recited in  claim 22 , wherein the first mode and the second mode are performed one of statically at a fixed temperature and dynamically in temporally fixed heating cycles. 
   
   
       24 . The glow plug as recited in  claim 22 , wherein the heating element is operated using mapping regulation. 
   
   
       25 . The glow plug as recited in  claim 22 , further comprising:
 a temperature sensor for monitoring a temperature of the heating element.   
   
   
       26 . The glow plug as recited in  claim 25 , wherein:
 a temperature of the heating element is monitored by monitoring an electrical resistance of the heating element.   
   
   
       27 . The glow plug as recited in  claim 23 , wherein when monitoring an electrical resistance of the heating element, the heating element is operated with switched current, and a temperature measurement for monitoring the electrical resistance of the heating element is performed in an interval between heating phases.