Classifications

• • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
  • F02—COMBUSTION ENGINES; HOT-GAS OR COMBUSTION-PRODUCT ENGINE PLANTS
  • F02M—SUPPLYING COMBUSTION ENGINES IN GENERAL WITH COMBUSTIBLE MIXTURES OR CONSTITUENTS THEREOF
  • F02M26/00—Engine-pertinent apparatus for adding exhaust gases to combustion-air, main fuel or fuel-air mixture, e.g. by exhaust gas recirculation [EGR] systems
  • F02M26/52—Systems for actuating EGR valves
  • F02M26/53—Systems for actuating EGR valves using electric actuators, e.g. solenoids
  • F02M26/54—Rotary actuators, e.g. step motors

Definitions

• the invention relates to a valve closing mechanism.
• valves are required to shut off or meter fluid flows.
• a regulation of the amount of recirculated exhaust gas is usually carried out as a function of the operating state of the engine. Valves are required for this regulation. This applies to numerous other applications, for example in the field of automotive technology and here for example for shutting off an exhaust stream, which is not returned, but reaches an exhaust system in which one or more switching flaps are provided to resonant body or cooler before catalysts or off.
• valves in use are widely different types.
• the valve In certain applications, in the field of automotive engineering, for example in the regulation, the connection or disconnection of an exhaust gas flow, the situation arises that the valve must be closed against an extremely high pressure, while in the closed state, a comparatively small force is required to keep the valve in the closed state.
• the reason for this is that, in the open state, in addition to the static pressure, which also bears against the valve in the closed state, there is the dynamic pressure due to the fluid flow. against this pressure, the valve must be closed, while this pressure is no longer present when the valve is closed due to the suppressed flow, so that a smaller force is sufficient to keep the valve in the closed state.
• the closing since the valve must be closed against fluid flow, the closing requires a high force, which in particular increases exponentially with the closing path, because the valve is increasingly exposed to the dynamic pressure of the fluid flow during closing.
• EP 0 856 657 A2 describes an exhaust gas recirculation valve in which a cam is fixedly connected to the motor shaft, so that a valve tappet can be actuated by means of the outer cam track.
• a closing spring is provided on the valve stem.
• a spring can be provided for an automatic return of the cam itself, which is supported on the housing.
• US Pat. No. 4,840,350 discloses an exhaust gas recirculation valve in which a rotary element for actuating the valve is rotated. Between the rotary member and a stationary member, a torsion spring is provided to effect a return. On the rotary member, a pin is provided in an eccentric position, to which a valve stem is mounted, by means of which the valve can be actuated.
• EP 1 028 249 A2 describes an exhaust gas recirculation valve with a gear ratio by means of gears, it being possible for a slip clutch to be provided on a gearwheel in order to avoid damage to the gearwheel in the event of overloading.
• the invention has for its object to provide a valve closing mechanism of simple design, by means of which the force required to close the valve force can be applied efficiently and reliably.
• This engine can be of any type.
• it may be an electric drive, for example in the form of an electric motor, in turn, for example, a stepper motor, a so-called.
• With the rotating motor shaft a so-called rotary part is connected. This rotating part is rotated to open and close the valve by the motor shaft.
• a so-called actuating part is further provided, which is rotatably and eccentrically mounted on the rotary member and resiliently connected thereto.
• a bearing for the actuating part is eccentric with respect to the motor shaft on the rotary part, For example, a protruding from the rotary member bearing bush provided.
• the operating part is rotatably mounted.
• a resilient connection which defines the position of rotary and operating part to each other.
• This arrangement normally acts in such a way that the force of the motor is transmitted from the rotary part via the resilient connection to the actuating part in such a way that it is rotated and can cause an opening and closing of the valve.
• an increasing force is required to close the valve.
• the dynamic pressure of the fluid flow to be blocked inhibits or brakes the closing movement of the valve.
• This effect also applies to the actuating part suitably connected to the valve. Due to the non-rigid, but resilient connection between the actuating part and the rotary member, however, the rotary member driven by the motor can continue to rotate in the closing direction, and the resilient connection is tensioned.
• the eccentric bearing of the operating member provided on the rotary member also moves circumferentially around the motor shaft.
• This movement of the eccentric bearing has the consequence that the actuating part, at least slightly moves, even against the growing force due to the dynamic pressure. This movement takes place according to the eccentricity of the bearing of the operating part.
• the arrangement relationship of the eccentric bearing of the operating part with respect to the motor shaft, especially in view of their movement when closing, is such that the bearing of the operating part at a rotation of the motor shaft, during the closing movement, slightly in Closing direction of the valve moves.
• This force can be used in the particular case that the valve to be closed due to the growing dynamic pressure must be closed by a force which exceeds the operating force of the engine, as an extremely high closing force, which closes the valve securely.
• the force transmitted via the eccentric bearing increases in accordance with the angle of rotation of the motor. This force builds up slowly and reaches its maximum when maximum use is made of the eccentricity.
• this closure takes place and the resilient connection between the rotary and actuating member causes the rotation of the two components with respect to each other is returned to the initial state.
• the force amplification described when closing a valve can be used to the effect that, for example in exhaust gas recirculation valves may occur that the valve remains open when the engine is stopped.
• a blockage of the valve could occur, at least to a small extent, because a valve rod sticks in its guide could.
• the mechanism according to the invention generates an extensive force that can be used to release such a bond.
• the invention is particularly suitable for, but not limited to, use as a valve which selectively opens or shuts off or regulates an exhaust flow.
• the valve closing mechanism according to the invention can also be used in conjunction with an exhaust gas flow at various locations.
• the use in connection with an exhaust gas recirculation valve is conceivable, which regulates the exhaust gas flow to be supplied on the fresh air side.
• the valve closing mechanism according to the invention can be provided in a region in which intake air and exhaust gas already mixed leave the valve housing.
• the valve-closing mechanism is applicable to arrangements in an exhaust system in which one or more valves may be provided to connect or disconnect, for example, coolers in the region of catalysts or sound boxes.
• valve closing mechanism according to the invention can also be used in the field of automotive engineering or other technical fields and develops its advantages in particular when fluids, ie any liquids or gases, flow through a valve, which are such that the described feature when closing a valve occurs.
• valve-closing mechanism according to the invention can also be used with any fluids, if it may be desirable in certain situations to apply an extremely excessive closing force on the valve.
• valve for the invention is irrelevant. Although in principle a rotational movement of the rotary and the operating part. This can be used to operate a valve that is between the opening and closing Closed position is rotated, for example, a flap valve.
• the invention is applicable to a lift valve by providing a suitable power transmission mechanism between the rotating operating member and the valve member to be moved translationally.
• special features and preferred embodiments reference is made in addition to the preceding and following explanations to the disclosure of EP 03 006 733 of the applicant. This application relates to a similar mechanism used when opening a valve. It will be appreciated that all of the measures referred to in this context, if used to some extent reversed, can be used for the present valve closure mechanism.
• the eccentric mounting of the actuating part on the rotary member is designed such that the eccentric bearing is moved at least slightly in the closing direction upon rotation of the motor shaft, starting from an open state of the valve.
• the desired effect is particularly reliable reachable.
• the rotary member has an eccentric pin
• the actuating member is provided with a circumferentially extending slot in which the pin is guided.
• the eccentric pin provided on the rotary part moves in the oblong hole of the actuating part.
• the eccentricity of the pin can be in the range of a few millimeters or centimeters.
• the resilient connection it is preferable for the resilient connection to be formed between the pin of the rotary member and the operating member.
• a pin may also be provided on the actuating part, and a torsion spring is aligned with its axis approximately in alignment with the motor shaft and anchored to the two pins.
• the actuation of the valve can be carried out directly by the actuating element.
• a suitable power transmission mechanism may be provided.
• the actuator be connected to the valve via a lever drive. In this way, a further over- or reduction of the force applied by the actuator force can be carried out and used in an advantageous manner for a reliable operation of the valve.

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• Engineering & Computer Science (AREA)
• Chemical & Material Sciences (AREA)
• Combustion & Propulsion (AREA)
• Mechanical Engineering (AREA)
• General Engineering & Computer Science (AREA)
• Mechanically-Actuated Valves (AREA)

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Cited By (1)

Citations (3)

• 2004
  • 2004-09-28 EP EP04023070A patent/EP1640593A1/fr not_active Withdrawn

Patent Citations (3)

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