Capacitive cylinder pressure sensor
AssigneeTeknologian tutkimuskeskus VTT Oy
InventorsTeuvo Sillanpää, Panu Koppinen, Kai-Erik Elers
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Abstract
A capacitive pressure sensor for an internal combustion engine is provided having a housing having a bottom surface, variable capacitor and circuitry. The variable capacitor is formed by a stationary electrode and an elastically bendable electrode. Pressure exerted on the bottom surface acts to bend the elastically bendable electrode. This bending alters the capacitance of the variable capacitor. The circuitry is configured to generate a signal based on the variable capacitance of the variable capacitor. This capacitance is representative of the pressure exerted on the bottom surface.
Claims20
A capacitive pressure sensor mountable to the cylinder head of an internal combustion engine, the capacitive pressure sensor comprising:
- a cylindrical housing having a threaded outer surface and a bottom surface;
- a variable capacitor having a stationary electrode and an elastically bendable electrode, the stationary electrode being disposed within the housing and the elastically bendable electrode being arranged between the stationary electrode and the bottom surface;
- and
- circuitry configured to generate a signal based on the variable capacitance of the variable capacitor, the signal being representative of a pressure exerted on the bottom surface;
- wherein the stationary electrode is disposed substantially perpendicular relative to the outer surface of the housing.
A capacitive pressure sensor apparatus mountable to the cylinder head of an internal combustion engine for measuring pressure in a cylinder of the engine, the sensor apparatus comprising:
- a cylindrical housing having a side wall;
- a stationary electrode disposed within the housing, and a movable electrode exposed and responsive to pressure changes in the cylinder, said electrodes forming a capacitor having a capacitance varying according to said pressure changes;
- and
- a circuitry disposed in the housing for generating a signal representing said varying capacitance,
- wherein the stationary electrode is disposed substantially perpendicularly relative to the side wall of the housing, and the movable electrode forms at least a part of the bottom wall of the housing.
Dependencies are inferred from the claim text.