Internal-combustion engines – Charge forming device – Exhaust gas used with the combustible mixture
Patent
1998-08-14
1999-11-02
Argenbright, Terry M.
Internal-combustion engines
Charge forming device
Exhaust gas used with the combustible mixture
25112907, 25112915, F02M 2507
Patent
active
059750642
DESCRIPTION:
BRIEF SUMMARY
PRIOR ART
The invention is based on an exhaust gas recirculation valve. In one such exhaust gas recirculation valve, known from German Patent Disclosure DE-A 43 38 194, the valve seat is embodied as a conical seat that points into the interior of the exhaust gas recirculation line. A conical valve member comes into contact with this seat and is put in the closing position by the force of the spring and lifted from the valve seat by the electromagnetic force of the electromagnet. Such a valve has the disadvantage of being urged in the closing direction by the exhaust gas pressure in the closing position, so that considerable forces are required, in particular additionally when there is negative pressure in the tube, to put the valve in the opening position. This necessitates a large-sized electromagnet and high energy, which must be furnished at high cost by suitably embodied end stages.
ADVANTAGES OF THE INVENTION
The exhaust gas recirculation valve has the advantage over the prior art that by furnishing the movable wall, an equalization of the exhaust gas pressures acting on the valve member can be attained at the valve member. Accordingly, the actuation forces that the valve must exert in the opening position are only slight, thus allowing fast, exact switching of the exhaust gas recirculation valve. Moreover, the electromagnet can be small in size and can be operated with only a small input of energy. The expense for an electric trigger stage for the winding of the electromagnet is correspondingly small as well. In an especially advantageous way, the exhaust gas recirculation valve can be held in intermediate positions by means of analog or quasi-analog triggering that is clocked with a variable duty cycle.
In an advantageous further feature, the communication of the control chamber is effected via a conduit passing through the valve shaft, so that an immediate communication is realized without a separate line laid between the exhaust gas recirculation line and the control chamber. The result is a particularly small structure that is easy to assemble with few opportunities for mistakes. For pressure equalization, particularly in accordance with claim 3, the surface area of the valve member acted upon in the closing direction by the exhaust gas pressure is substantially equal in size to the surface area of the movable wall that acts in the opening direction of the valve member. By way of the dimensioning of this surface area, the closing force with the electromagnet not excited and the opening force of the electromagnet can be adjusted exactly. In a further advantageous feature, the movable wall comprises a diaphragm. The embodiment of the exhaust gas recirculation valve has the advantage that in the event of a crack in the diaphragm, the compensation for the exhaust gas pressure in the closing direction is dispensed with, and the valve can be kept securely closed by the exhaust gas pressure upstream of the valve member. A partial stream of exhaust gas then passes via the control chamber, the torn diaphragm, and the pressure chamber into the tube in the form of a partial quantity of an exhaust gas recirculation, which can be defined by the cross section of the conduit. In particular, if the diaphragm fails, hot exhaust gas is prevented from flowing out into the surroundings of the exhaust gas recirculation valve and reaching the engine compartment of the associated motor vehicle, where it could cause damage.
In another advantageous feature, the movable wall is embodied as a piston, so that failure of the kind that can be possible if a diaphragm is used is reliably avoided. With this embodiment, above all, the surface areas that act upon the valve member in compensation for the exhaust gas pressure in the closing direction of the valve can be determined very accurately. In an advantageous further feature a shielding cap is provided on the valve member, ahead of the mouth of the conduit; it assures that the pressure in the control chamber is not varied as a function of a dynamic head pressure but rathe
REFERENCES:
patent: 4921208 (1990-05-01), LaMarca
patent: 5065979 (1991-11-01), Detweiler et al.
patent: 5188073 (1993-02-01), Ejiri et al.
patent: 5701874 (1997-12-01), Sari et al.
patent: 5785034 (1998-07-01), Moedinger et al.
Hezel Bruno
Jauernig Peter
Krimmer Erwin
Miehle Tilman
Wizgall Eberhard
Argenbright Terry M.
Castro Arnold
Greigg Ronald E.
Griegg Edward E.
Robert & Bosch GmbH
LandOfFree
Exhaust gas recirculation valve for an internal combustion engin does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Exhaust gas recirculation valve for an internal combustion engin, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Exhaust gas recirculation valve for an internal combustion engin will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-2122355