Knock sensor
AssigneeRobert Bosch GmbH
InventorsRobert Entenmann, Joerg Bonitz, Stefan Unland, Romuald Fries, Robert Sloboda, Klaus Schenk, Karl Dums
Life of this patent
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Abstract
A knock sensor for indirect or direct fixing to an internal combustion engine has a housing (10) with a pressure sleeve (11) on the outer side of which a piezoceramic disk, a seismic mass (16), the contact disks (14), and the insulating disks (13) are arranged. The insulating disks (13) or the piezoelectrical disk (15) are or is made slightly electrically conductive so that the voltage spikes which occur due to the pyroelectrical effect can be easily eliminated. In this way, faulty measuring and interference can be avoided in the electrical circuit connected to the knock sensor.
Claims25
Knock sensor for an internal combustion engine, said knock sensor comprising
- a housing (10);
- at least one piezoelectrical element (15) arranged between contact disks (14), said at least one piezoelectrical element (15) and said contact disks (14) residing in said housing (10);
- a seismic mass (16) for picking up vibrations of the internal combustion engine, said seismic mass being positioned to act on said at least one piezoelectrical element (15);
- and
- at least one insulating disk (13) arranged between a support surface in said housing and one of said contact disks (14) and at least one other insulating disk (13) arranged between said seismic mass (16) and another of said contact disks (14),
- wherein said at least one insulating disk (13) and said at least one other insulating disk (13) are made of electrically conductive material having an electrical conductivity less than that of said contact disks (14) but large enough to eliminate electrical charges generated by a pyroelectric effect.
Knock sensor for an internal combustion engine, said knock sensor comprising
- a housing (10);
- at least one piezoelectrical element (15) arranged between contact disks (14), said at least one piezoelectrical element (15) and said contact disks (14) residing in said housing (10);
- a seismic mass (16) for picking up vibrations of the internal combustion engine, said seismic mass being located so as to act on said at least one piezoelectrical element (15);
- and
- at least one insulating disk (13) arranged between a support surface (12) in said housing and one of said contact disks (14) and at least one other insulating disk (13) arranged between said seismic mass (16) and another of said contact disks (14),
- wherein said at least one piezoelectrical element (15) is doped with an electrically conductive material so as to eliminate electrical charges generated by a pyroelectric effect.
Knock sensor for an internal combustion engine, said knock sensor comprising
- a housing (10);
- at least one piezoelectrical element (15) arranged between contact disks (14), said at least one piezoelectrical element (15) and said contact disks (14) residing in said housing (10);
- a seismic mass (16) for picking up vibrations of the internal combustion engine, said seismic mass being located so as to act on said at least one piezoelectrical element (15);
- and
- at least one insulating disk (13) arranged between a support surface in said housing and one of said contact disks (14) and at least one other insulating disk (13) arranged between said seismic mass (16) and another of said contact disks (14),
- wherein said at least one insulating disk (13) and said at least one other insulating disk (13) consist of electrically conductive material having an electrical conductivity less than that of said contact disks (14) and said at least one piezoelectrical element (15) is doped with an electrically conductive material so as to eliminate electrical charges generated by a pyroelectric effect.
Dependencies are inferred from the claim text.