Piezo Common Rail Injectors with Direct Control of Injector Switching

Abstract

The invention relates to a piezoelectric common rail fuel injector that directly controls the switch of the fuel injector, including a piezoelectric stack, a fuel injector body, an integral needle valve, a sealing pin installed in the inner cavity of the fuel injector, a guide block, Positioning sleeve, spacer, lever, spring force adjustment washer and return spring; guide block, positioning sleeve and spacer are fixed in the inner cavity of the fuel injector and arranged in sequence from top to bottom; the guide block is provided with the first Inner hole; the sealing pin is an I-shaped piece, which is located below the piezoelectric stack, and its middle part is inserted into the first inner hole of the guide block; a rectangular hole is arranged in the positioning sleeve, and the lever is located in it and below the sealing pin. The longitudinal section contains three fulcrums c, d, e; the lever is connected with the integral needle valve, and after receiving the downward force of the sealing pin, it drives the integral needle valve to move upward; the spring force adjustment gasket and the return spring are set on the integral needle valve . The invention has a simple structure, and effectively solves the problem in the prior art that long-time energized work affects the service life of electronic components.

Description

technical field [0001] The invention belongs to the technical field of an electronically controlled common rail fuel injection system for diesel engines, and relates to a piezoelectric common rail fuel injector that directly controls the switch of a fuel injector. Background technique [0002] Diesel engine common rail fuel injection system is an intelligent fuel injection system controlled by an electronic computer, and it is the only choice for diesel engines to meet China V and China VI emission standards. [0003] At present, since the injection pressure of the diesel engine is between 180 and 220 MPa, the hydraulic pressure acting on the needle valve of the nozzle is very large, and the expansion and contraction of the piezoelectric stack is very small, between 0.04 and 0.06, and the lift of the nozzle is between 0.2 and 0.3 , so the lift of the piezoelectric stack must be enlarged. In the past, diesel engines used common rail injectors controlled by piezoelectric crys...

AI Technical Summary

Problems solved by technology

In the past, diesel engines used common rail injectors controlled by piezoelectric crystals under the servo control method. The piezoelectric stack indirectly controlled the opening and closing of the injector through a pilot valve, but the opening and closing speed of the needle valve was relatively slow through the servo valve. , affecting the fuel supply rate, thereby affecting the diesel engine emission index, and using a pilot valve, a large amount of high-pressure fuel (about 20% or more of the total fuel volume) flows into the low-pressure chamber through the gap between the coupling parts and the oil outlet orifice, resulting in energy loss and system heating.

In addition, the structure of the common rail injector controlled by piezoelectric crystal is complex and difficult to process, and the fuel supply curve changes with the fuel supply pressure, making it difficult to adjust the fuel injector

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