Liquid control valve

Abstract

The invention relates to a liquid control valve which is provided, for its operation, with a bonding chamber (30) filled with liquid and placed between a piston of a piezoelectric actuator (32) and a piston (25) that actuates a valve member. In order to compensate for liquid loss occurring in a bonding chamber (30) when briefly exposed to high pressure in each cycle of operation, the pressure differential existing in the low pressure chambers between, on the one hand, the bonding chamber (30) and, on the other hand, the piston surfaces (31) of the piezoelectric actuator (32) and the surfaces of the piston (25) that actuates the valve member, the surfaces being in both cases turned to the side opposite the bonding chamber (30), is used during the return stroke of the actuator piston (31) to have a refilling completed along slots (35, 36) without using any valve. This type of valve is intended for use in fuel injection systems of internal combustion engines for vehicles.

Description

technical field [0001] The present invention relates to a liquid control valve and an injection system using the valve. Background technique [0002] A similar valve is disclosed by EP0477400. Among them, the driving piston of the valve element is sealed and movably arranged in a small diameter part of a stepped hole, and a piston with a larger diameter driven by a piezoelectric actuator is set in a larger diameter part of the stepped hole . A fluid chamber is sandwiched between the two pistons in such a way that when the piston with the larger diameter is pushed a certain distance through the actuator, the drive piston of the valve element is pushed a greater distance in proportion to the transition ratio of the stepped bore cross section . The valve element, the driving piston, the piston with a larger diameter and the piezoelectric actuator are sequentially located on the same axis. [0003] The aforementioned valves have the problem that changes in length of the piez...

AI Technical Summary

Problems solved by technology

A device for completing refilling has been disclosed in the prior art mentioned at the beginning, but this device has the following disadvantages, that is, between the coupling chamber and a closed oil storage tank with a constant volume, there is always a gap between the two. One possible flow direction is open, which greatly affects the performance of the piezoelectric actuator.

In particular, the resulting increased volume leads to a compressibility that reduces the transport stiffness of the liquid column formed by the coupling chamber

The known devices mainly also have coupling chamber leaks that occur to compensate for tolerances in the working stroke

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