A kind of fuel injection valve and diesel engine

Abstract

The invention discloses a fuel injection valve and a diesel engine, which belong to the field of engine fuel injection valves. The control valve sleeve of the fuel injection valve is provided with an oil outlet passage, and a throttle orifice is provided with a low-pressure oil passage, which is beneficial to reduce The risk of cavitation corrosion on the sealing cone surface at the top of the small throttle orifice; the first throttle ring and the second throttle ring are successively formed between the long needle valve and the inner wall of the control valve sleeve during the lifting process, and the first throttle The areas of the annular belt and the second throttle annular belt gradually increase with the rise of the long needle valve, and the first throttle annular belt and the second throttle annular belt play a throttling role together, so that the oil flows into the control chamber from the oil inlet hole The flow of high-pressure oil in the valve decreases rapidly, so that the pressure in the control chamber drops rapidly, and the opening delay is shortened; the areas of the first throttle ring and the second throttle ring gradually decrease with the decline of the long needle valve, and the oil inlet The flow of high-pressure oil flowing into the control chamber from the hole increases gradually, and the pressure in the control chamber builds up rapidly, which improves the closing speed of the long needle valve and shortens the closing delay time.

Description

technical field [0001] The invention relates to the technical field of engine fuel injection valves, in particular to a fuel injection valve and a diesel engine. Background technique [0002] In order to meet the increasingly stringent emission requirements, fuel injection valves, which have an important impact on diesel engine emissions, need to further improve their injection accuracy and response speed. At present, for the high-pressure common rail injection system, the fuel injection valve controls the opening and closing of the needle valve through the control valve. The orifice in the control valve generally realizes the exchange of the fuel in the control chamber with the outside world through the oil inlet orifice and the oil outlet orifice. The oil inlet hole introduces high-pressure oil into the control chamber to generate closing force on the needle valve, and the oil outlet hole releases high-pressure oil into the low-pressure oil chamber to reduce the closing f...

AI Technical Summary

Problems solved by technology

[0003] In the existing fuel injection valve, there is only one oil outlet orifice and an oil inlet orifice, and the flow rate of the oil inlet orifice should be smaller than the oil outlet orifice flow, so as to realize the control of the opening and closing of the needle valve. However, due to the The throttling effect of the oil orifice on the high-pressure oil, the oil inlet speed is slow, and it takes a long time for the high-pressure oil to fill the control chamber through the oil inlet orifice after the injection, which leads to too much delay in the closing of the needle valve. Large, slow response, unable to meet the needs of multiple injections and precise control of oil volume

[0004] In order to solve this technical problem, a fuel injection valve is proposed in the prior art, which adopts a two-position three-way control valve structure. This structure realizes the oil discharge of the oil outlet orifice at the time of fuel injection through the control valve, The function of injecting oil in the opposite direction when oiling realizes one hole for dual purposes and improves the closing speed of the needle valve. However, the structure of the injection valve is complicated, and it is difficult to process and assemble, and there are many coupling parts in it, and the static leakage of fuel in actual work The volume is large, and long-term work has a greater impact on the sealing cone surface in contact with the throttle orifice and the ball valve, and cavitation is prone to occur at the sealing cone surface

Images