Pressure sensor for the combustion chamber of an internal combustion engine

US4494401A · kind A · utility

Assignee

• Robert Bosch GmbH · DE

Inventors

• Klaus Dobler · Gerlingen, DE
• Ulrich Schoor · Stuttgart, DE
• Rudolf Heinz · Renningen, DE
• Thomas Frey · Friolzheim, DE
• Werner Grunwald · Gerlingen, DE

Key dates

• Filing date: Oct 11, 1983
• Grant date: Jan 22, 1985
• Expiry date: Oct 11, 2003

Classification

• Technology area (CPC F): Mechanical Engineering; Lighting; Heating
• CPC primary: F23Q2007/002
• WIPO field: Measurement
• WIPO sector: Instruments

Abstract

To sense pressure within the combustion chamber of an internal combustion engine (ICE), a plug element which already extends into the combustion chamber of the ICE, such as a sparkplug, or a glow plug, has a layer-like resistor applied to a ceramic insulator extending into the combustion chamber, for example, directly on the central insulator of a sparkplug or on the side of a ceramic glow plug bushing or plug element. If applied to a sparkplug then, preferably, the heater is shielded by metallic layers, separated from the metallic shielding layers by insulating layers, of which the top metallic layer preferably is platinum or a platinum-type metal to catalyze combustion of residues which, otherwise, might collect on the top layer and interfere with proper sensor operation. The layer-like sensor and conductive tracks may be of thick film construction; stamp-on printing with flexible printing stamps is suitable to apply the layer-like resistors.