Fluid handling – Line condition change responsive valves – With separate connected fluid reactor surface
Patent
1996-06-19
1999-05-11
Hepperle, Stephen M.
Fluid handling
Line condition change responsive valves
With separate connected fluid reactor surface
137510, 251337, F02M69/54
Patent
active
059017422
DESCRIPTION:
BRIEF SUMMARY
BACKGROUND OF THE INVENTION
The invention is based on a pressure control valve for an internal combustion engine. A pressure control valve is already known (U.S. Pat. No. 5,078,167) that is disposed on a fuel filter of a fuel supply system for an internal combustion engine and that has a base body in the middle region of which a tubular valve seat body with a valve seat face is secured. Between the base body and the valve seat body, a diaphragm is fastened firmly into the middle region, its periphery being fastened to a flange of the base body. A fuel inlet neck protrudes with great play into the valve seat body and is connected to the pressure side of the fuel feed pump. Some of the fuel flowing via the fuel inlet neck reaches the valve seat body and from there passes through the filter cloth of the fuel filter and after that, via an opening in the base body, acts on a pressure control side of the diaphragm. Connected to the return side of the diaphragm, remote from the pressure control side of the diaphragm, is a valve closing body, which in sealed fashion surrounds the fuel inlet neck and is displaced on the diaphragm by a motion of the diaphragm, so as to be lifted more or less away from the valve seat face of the valve seat body, counter to the force of a compression spring engaging the return side of the diaphragm. Such a pressure control valve is very complicated in design and because of the friction resulting from the sealing of the valve closing body on the fuel inlet neck, there is undesirable hysteresis and imprecision of control. Moreover, the valve closing body has a very large mass, which must be moved by the diaphragm fastened in its middle region and on its periphery firmly to the base body, and as a result the reaction speed of the pressure control valve to pressure changes is also impaired.
A pressure control valve is also known (U.S. Pat. 4,300,510) that is disposed on a fuel distributor line. A diaphragm of the pressure control valve is fastened on its periphery between an annular flange and the cap and in its middle region supports a valve closing body, which cooperates with a flat valve seat face on a valve seat body protruding into the fuel distributor line. A compression spring is supported on the side of the diaphragm remote from the valve seat body and on its other end rests on the cap. The pressure of the engine prevailing in the air intake line also acts on the side of the diaphragm remote from the valve seat body. Such a pressure control valve has the disadvantage that the masses that must be moved by the diaphragm are still relatively great, so that the reaction speed in the event of pressure changes is still too slow.
ADVANTAGES OF THE INVENTION
A pressure control valve of the invention, has the advantage over the prior art that it can be made in a simple way without major effort or expense, is compact in structure precisely controls the predetermined pressure, and reacts more quickly to pressure changes. The pressure control valve of the invention is also especially well-suited for controlling pressure in so-called "returnless" fuel injection systems, in which the excess fuel, pumped by the fuel pump and not injected through the injection valves, is returned to the fuel tank directly downstream of the fuel pump via the pressure control valve. Routing the return conduit through the diaphragm leads to a reduction in the masses moved and thus to an improvement in the reaction speed of the pressure control valve. The axial flow has advantages from the installation standpoint and enables better integration with other units.
Advantageous further features of and improvements to the pressure control valve are possible with the provisions recited.
As the valve closing body, it is especially advantageous to use a ball, which as is known can be made with high precision. It is also advantageous to flatten this ball so that it has a flat sealing face, which cooperates with a flat valve seat face that is moved by the diaphragm.
It is advantageous to embody the base body as a cup-shape
REFERENCES:
patent: 5065725 (1991-11-01), Spoetter
patent: 5076320 (1991-12-01), Robinson
patent: 5435345 (1995-07-01), Robinson et al.
Bueser Wolfgang
Drutu Lorenz
Frank Kurt
Kleppner Stephan
Liskow Uwe
Greigg Edwin E.
Greigg Ronald E.
Hepperle Stephen M.
Robert & Bosch GmbH
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