Cylinder pressure monitoring system
AssigneeCreative Tool Company
InventorsDaniel J. Dooley, Terrence L. Dooley, Joseph L. Dooley
Life of this patent
Estimating the term…
Abstract
Disclosed is a transducer assembly and diagnostic apparatus for processing an electrical signal which varies with the pressure changes occurring within an engine cylinder. The transducer assembly consists of a U-shaped structure integrally formed in a sandwich arrangement and encompassing a pressure-responsive crystalline element. The assembly is sized such that it substantially encompasses the shank of a spark or glow plug of the engine such that axial forces from within the cylinder excite the transducer through the plug to produce a signal which is processed in an electrical circuit to provide timing or other diagnostic information.
Claims16
A transducer for developing an electrical signal in response to pressure variations within the combustion chamber of an engine of the type having (a) a threaded port extending from the combustion chamber to the outer surface of the engine and (b) a glow or spark plug having a shank portion threaded into said port and an enlarged head portion exterior to said shank portion, said transducer comprising:
- a housing sized and shaped for insertion around said shank portion while underlying said enlarged head portion, said housing having a thickness sufficient to insure that said glow or spark plug head portion compresses said housing against said engine and seats against said housing;
- a piezoelectric element disposed within said housing for developing an electrical signal in response to pressure variations on said glow or spark plug from within said combustion chamber;
- and
- terminal means for transmitting the electrical signal from said piezoelectric element.
A transducer for developing an electrical signal in response to pressure variations within the combustion chamber of an engine of the type having a port which is at least partially threaded extending from said combustion chamber through the engine and a glow or spark plug having a shank portion threaded into said port and an enlarged head portion, said transducer comprising;
- a substantially flat U-shaped element sized and shaped for insertion around the shank portion of said glow or spark plug while substantially underlying the expanded head portion of said glow or spark plug, said U-shaped element being of sufficient thickness to insure that the enlarged head portion of said plug seats firmly against said element;
- a piezoelectric crystalline element sandwiched within said U-shaped element for producing an electrical signal in response to axial pressure variations on said glow or spark plug from within said combustion chamber;
- and
- output terminal means for transmission of said electrical signal.
In combination with a diesel engine of the type having a combustion chamber associated with each cylinder and a threaded port from each combustion chamber to the outer surface of the engine into each of which is inserted a glow or spark plug having a shank portion threaded into said port and an enlarged head portion exterior to said shank portion and a transducer for developing an electrical signal in response to pressure variations within a combustion chamber, said transducer comprising
- a housing sized and shaped for insertion around said shank portion and underlying said enlarged head portion, said housing having a thickness sufficient to insure that said glow or spark plug head portion compresses said housing against said engine and seats against said housing;
- a piezoelectric element disposed within said housing for developing an electrical signal in response to pressure variations on said glow or spark plug from within the combustion chamber;
- and
- terminal means for transmitting the electrical signal from said piezoelectric element.
A monitoring system for fuel injected engines of the type having a spark or glow plug with an expanded head portion and a shank portion threaded into a port extending through the engine into the cylinder combustion chamber, said monitoring system comprising:
- a transducer assembly having a size and shape for surrounding said shank portion while underlying said head portion and a thickness sufficient to prevent said plug from seating internal to said port such that said transducer assembly is compressed by said expanded head portion against the engine so as to develop an electrical signal containing information corresponding to changes in axial pressure on said spark or glow plug from within said combustion chamber;
- circuit means for processing said electrical signal;
- and
- output indicating means coupled to said circuit means for providing a visual indication of at least a portion of said pressure information.
A method for dynamically monitoring the performance of an internal combustion engine of the type having at least one spark or glow plug threaded into a receptacle which extends from the outside of the engine into a cylinder combustion chamber and which plug has an enlarged head portion exterior to said engine, said method comprising the steps of:
- at least partially unscrewing said plug from its receptacle so as to unseat said plug from the engine;
- inserting around said plug a pressure responsive transducer which is shaped to fit around said plug between said enlarged plug head portion and the outer face of said engine;
- screwing said plug back into its receptacle until the enlarged head portion compresses said transducer against the outer face of said engine so that axial pressures on said plug from within said cylinder create pressure variations on said transducer which generate a transducer output signal.
A transducer assembly for developing an electrical signal indicative of pressure variations within the combustion chamber of an engine of the type having (a) an at least partially threaded port extending from said combustion chamber to the exterior of said engine and (b) a spark or glow plug threaded into said port and having a shank portion extending into said receptacle and an enlarged head portion exterior to said engine, said assembly comprising
- spacer means adapted to be compressed between said enlarged plug head portion and the exterior of said engine, said spacer means having sufficient thickness to prevent seating of said shank portion interior to said engine port;
- and
- a pressure responsive transducer element coupled to said spacer means and compressable therewith between said enlarged plug head portion and said engine so as to develop an electrical signal in response to pressure variations acting axially along said plug.
Dependencies are inferred from the claim text.