Claims
- 1. An electrically-operated canister purge valve for controlling purging of fuel vapors from a vapor collection canister to an internal combustion engine in accordance with a purge control signal that sets the extent to which the canister purge valve allows purge flow, the canister purge valve having an operating mechanism which comprises a linear solenoid actuator having a central longitudinal axis, the linear solenoid actuator comprising an electromagnet coil and stator structure associated with the coil for conducting magnetic flux created as a result of electric current flow in the coil, the stator structure comprising an air gap disposed coaxial with the axis, a mass that is positioned by the linear solenoid actuator along the axis, the mass including an armature disposed coaxial with the axis proximate the air gap for positioning along the axis as a function of magnetic force resulting from electric current flow in the coil and a valve element that is positioned axially by and with the armature in relation to a valve seat for establishing the extent to which the canister purge valve allows flow through the purge flow path, the mass bearing a relationship to electric current flow in the coil such that over a range of less than fully open positions wherein the valve element is unseated from the valve seat, the mass is positionable to plural discrete positions within that range each discrete position corresponding to a respective D.C. current component value of the electric current flow in the coil.
- 2. An electrically-operated canister purge valve as set forth in claim 1 in which the mass, while positioned at any particular one of the plural discrete positions within the range, can follow a fluctuating component of the electric current flow in the coil without the valve element contacting the valve seat.
- 3. An electrically-operated canister purge valve as set forth in claim 1 in which the electromagnet coil comprises a through-hole that is coaxial with the axis, and the air gap is disposed within the through-hole of the electromagnet coil.
- 4. An electrically-operated canister purge valve as set forth in claim 1 in which the operating mechanism includes a bias spring for exerting a spring force to urge the mass along the axis in a direction of seating the valve element on the valve seat.
- 5. An electrically-operated canister purge valve as set forth in claim 4 in which the bias spring has a substantially linear force vs. compression characteristic.
- 6. An electrically-operated canister purge valve as set forth in claim 1 further including an electric circuit for applying the purge control signal to the valve as a pulse-width-modulated signal that creates electric current in the coil which comprises a D.C. component for causing the mass to be positioned to a respective one of the plural discrete positions, and a fluctuating component that causes the mass to execute a fluctuating motion along the axis about the respective one of the plural discrete positions without the valve element contacting the seat.
- 7. An electrically-operated canister purge valve for controlling purging of fuel vapors from a vapor collection canister to an internal combustion engine in accordance with a purge control signal that sets the extent to which the canister purge valve allows purge flow, the canister purge valve comprising a linear solenoid actuator having a central longitudinal axis, the linear solenoid actuator comprising an electromagnet coil and stator structure associated with the coil for conducting magnetic flux created as a result of current flow in the coil, the stator structure comprising an air gap disposed coaxial with the axis. an armature that is disposed coaxial with the axis, proximate the air gap for positioning along the axis as a function of magnetic force resulting from current flow in the coil a valve element that is positioned axially by and with the armature in relation to a valve seat for establishing the extent to which the canister purge valve allows flow through the purge flow path, the armature having an association with the stator structure such that an axial component of magnetic force acting on the armature in a direction that increasingly opens the valve, is substantially linearly related to the average current flow in the coil over an operating range of average current flows, a bias spring that exerts a spring force that urges the armature and valve element toward the valve seat, and an electric circuit for applying the purge control signal to the valve as a pulse-width-modulated signal that creates in the coil an electric current waveform which comprises a D.C. component that is selectable over a range of D.C. component values for causing the armature to be positioned to a corresponding position along the axis over a range of positions linearly related to the range of D.C. component values, and a fluctuating component that is related to frequency of the pulse-width-modulated signal to cause the armature to execute a fluctuating motion along the axis about the position to which the armature is positioned by the D.C. component.
- 8. An electrically-operated canister purge valve comprising a purge flow path adapted to be disposed between an intake manifold of an internal combustion engine and a fuel vapor collection canister of a fuel vapor collection system for such an engine, wherein such a canister collects vapor generated by volatile fuel in a fuel tank, said canister purge valve controlling the purging of such a canister to such an intake manifold in accordance with a purge control signal that sets the extent to which said canister purge valve allows purge flow through said purge flow path, said canister purge valve comprising a linear solenoid actuator having a central longitudinal axis and comprising an electromagnet coil and stator structure associated with said coil for conducting magnetic flux created as a result of current flow in said coil, said stator structure comprising an air gap disposed coaxial with said axis, an armature that is disposed coaxial with said axis proximate said air gap for positioning along said axis as a function of magnetic force resulting from current flow in said coil, a valve element that is positioned axially by and with said armature in relation to a valve seat for establishing the extent to which the canister purge valve allows flow through said purge flow path, said armature having an association with said stator structure such that an axial component of magnetic force acting on said armature in a direction that increasingly opens said valve, is substantially linearly related to the average current flow in said coil over an operating range of average current flows, a bias spring that exerts a spring force that urges said armature and valve element toward said valve seat, and an electric circuit for applying the purge control signal to the valve as a pulse-width-modulated signal that creates in the coil an electric current waveform which comprises a D.C. component that is selectable over a range of D.C. component values for causing the armature to be positioned to a corresponding position along said axis over a range of positions linearly related to the range of D.C. component values, and a fluctuating component that is related to frequency of the pulse-width-modulated signal to cause the armature to execute a fluctuating motion along the axis about the position to which the armature is positioned by the D.C. component.
- 9. An electrically-operated canister purge valve as set forth in claim 8 in which the electromagnet coil comprises a through-hole that is coaxial with the axis, and the air gap is disposed within the through-hole of the electromagnet coil.
- 10. An electrically-operated canister purge valve as set forth in claim 8 in which the bias spring also has a substantially linear force vs. compression characteristic.
Parent Case Info
This a divisional of application Ser. No. 08/739,741 filed on Nov. 7, 1996 now U.S. Pat. No. 5,727,532.
US Referenced Citations (22)
Foreign Referenced Citations (1)
Number |
Date |
Country |
0015167 |
Jan 1982 |
JP |