Patent ID: 6293303
Filing Date: 2001-09-25
Classification: F01L,G01D,Y10T

Abstract:
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; andfurther 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.