Valve position detector
AssigneeFuji Oozx Inc.
InventorsAkiyoshi Mori, Makoto Adegawa, Haruki Kobayashi
Life of this patent
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Abstract
A poppet valve moves up and down in a valve operating mechanism in an internal combustion engine. A fixed electrode is supported on a cylinder head, and a moving electrode is carried by the poppet valve. The fixed electrode is connected to a circuit, which together comprises a variable condenser and a resistance. The valve moves up and down during firing operation of the engine. Variation in electrostatic capacitance is detected by means of the two electrodes, transmitted to the circuit via a lead and a ground connection, and converted to a voltage by the circuit, thereby enabling detecting valve position more exactly.
Claims5
A valve position detector, for detecting a position of a poppet valve driven by a valve operating mechanism, a valve stem of said valve being slidably supported by a cylinder head, said detector comprising:
- a variable capacitance electrode of an electrostatic capacitance sensor configured for detecting a position of said valve by detecting a variation in electrostatic capacitance when said valve is moved, said variable capacitance electrode being provided between said cylinder head or a stationary member integrally formed therewith, and said valve or a member which follows said valve,
- wherein said variable capacitance electrode further includes:
- a cylindrical fixed electrode which surrounds a valve stem of said valve concentrically with said valve stem, and is carried by the cylinder head;
- a cylindrical moving electrode carried by a valve spring retainer fixed to said valve, said fixed electrode and said moving electrode being configured so that they can be at least partially overlapped to form an opposing area varying to provide variable capacitance;
- and
- further comprising a tubular cover mounted between the valve spring retainer and the fixed electrode, configured to prevent foreign substances from invading between said two electrodes.
Dependencies are inferred from the claim text.