Pressure measuring glow plug

Abstract

This disclosure relates to a glow plug comprising a housing tube, a glow element, which protrudes from the housing tube and is movable against a return force in the longitudinal direction of the housing tube, an inner pole connected to the glow element for applying supply voltage to the glow element, and a sensor for measuring a pressure acting on the glow element. According to this disclosure, a ground contact of the sensor, which is in the form of a tube or a sleeve, surrounds a section of the inner pole, and a signal contact of the sensor extends between the ground contact and a wall of the housing tube.

1 - 11 . (canceled) 
     
     
         12 . A glow plug comprising:
 a housing tube;   a glow element, which protrudes from the housing tube and is movable against a reset force in the longitudinal direction of the housing tube;   an inner pole electrically connected to the glow element for applying a supply voltage to the glow element;   a sensor for measuring a pressure acting on the glow element;   a ground contact of the sensor, said ground contact comprising a tube or sleeve surrounding a section of the inner pole; and   a signal contact of the sensor extending between the ground contact and a wall of the housing tube.   
     
     
         13 . The glow plug according to  claim 12 , wherein the sensor comprises a piezoelectric sensor. 
     
     
         14 . The glow plug according to  claim 12 , wherein the sensor comprises a ring surrounding the inner pole. 
     
     
         15 . The glow plug according to  claim 12 , wherein the ground contact is connected on a side of the sensor facing the glow element, and the signal contact of the sensor is connected on an opposing side of the sensor facing away from the glow element. 
     
     
         16 . The glow plug according to  claim 12 , wherein both the ground contact and the signal contact have an overhanging end section that contacts the sensor. 
     
     
         17 . The glow plug according to  claim 16 , wherein the overhanging end section of the signal contact is located between an insulator ring and the sensor. 
     
     
         18 . The glow plug according to  claim 12 , wherein the ground contact of the sensor is electrically insulated with respect to the tube housing. 
     
     
         19 . The glow plug according to  claim 12 , wherein the inner pole is connected to a potential connection of the glow element and the tube housing is connected to a ground connection of the glow element. 
     
     
         20 . The glow plug according to  claim 12 , wherein the signal contact of the sensor encloses the ground contact. 
     
     
         21 . The glow plug according to  claim 20 , wherein the ground contact of the sensor protrudes at both ends thereof from the signal contact of the sensor. 
     
     
         22 . The glow plug according to  claim 12 , wherein the inner pole protrudes at both ends thereof from the ground contact of the sensor.