Pressure control valve with pressurized membrane

#The invention relates to a pressure control valve with a pressurized membrane for closing and opening a gas passage.

#Holch, U.S. Pat. No. 5,090,393, for instance, discloses the integration of a pressure control valve in an intake path for the internal combustion engine of a motor vehicle. This pressure control valve is, for instance, installed in a ventilation line between the crankcase and the air intake duct or the air filter, or into the ventilation line of the fuel tank in a motor vehicle by means of two flanges. In each case, the object is to prevent the pressure or the negative pressure in the units that are to be vented from exceeding a predefined value. To this end, a membrane is provided, which by opening a duct, for instance against the force of a valve spring, controls the passage and closes it if necessary.

#In this known arrangement, on the membrane side opposite the unit to be vented, a ventilation bore is present inside the valve housing, which pressurizes the valve chamber with atmospheric pressure. In many applications, however, the supply of atmospheric pressure is very complex, for example, if the pressure control valve is located in a sealed pressure chamber. In this case, the atmospheric or ambient pressure would have to be supplied by means of an additional duct or a hose or the like.

#The invention will be described in further detail hereinafter with reference to an illustrative preferred embodiment shown in the accompanying drawing FIGURE which is a sectional side elevation of a pressure control valve according to the invention having a pressurized membrane for closing and opening a gas passage in a ventilation arrangement for a crankcase of an internal combustion engine in a motor vehicle.

#The FIGURE shows an arrangement with a pressure control valve 1. In practical operation, this pressure control valve 1, which is installed in a ventilation line between the air intake duct and the crankcase of an internal combustion engine (not shown), draws in blow-by gases from the engine crankcase in the direction of arrow 2.

#Gas entry 3 is connected with the crankcase and is arranged at a distributor plate or a roll of a non-woven material. A membrane 5 is provided, which under pressure of a helical spring 6 abutting the housing of a valve chamber 8, is pushed against an opening 7 representing the gas passage, which can be closed by means of the membrane 5. The opening 7 leads into a volume with an ambient pressure Pamb, normally atmospheric pressure.

#To assure that valve chamber 8 has ambient pressure as well, a ventilation hole 9 is arranged directly in the membrane 5, so that a movement of the membrane 5 to open and close the opening 7 can be effected directly by the pressure differences between the ambient pressure Pamb and the pressure inside the crankcase of the engine.