WO2017028537A1

WO2017028537A1 - Fuel injector for marine diesel engine

Info

Publication number: WO2017028537A1
Application number: PCT/CN2016/077377
Authority: WO
Inventors: 唐文献; 章金鑫; 张建; 刘博�; 李大保; 王筱蓉; 刘辰朋; 晏飞
Original assignee: 江苏科技大学
Priority date: 2015-08-14
Filing date: 2016-03-25
Publication date: 2017-02-23
Also published as: CN105134439B; CN105134439A

Abstract

A fuel injector for a marine diesel engine comprises a main body (1), a plunger assembly and a solenoid valve control module. The main body (1) receives high-pressure fuel via a high-pressure fuel tube, the high-pressure fuel reaches an opening-closing plunger cavity via an internal fuel channel, and at the same time, a high-pressure servo hydraulic oil reaches a control plunger cavity via an internal oil channel. Under the action of the pressure of the high-pressure fuel and servo hydraulic oil, the opening-closing plunger (2) stops at a top dead center. A control opening of an external solenoid valve (8) is switchably connected to a high-pressure oil channel or a low pressure oil channel by using a control signal to perform rapid switching, so as to change a liquid pressure in a control chamber and a downward stroke of a control plunger (9), and in turn pressurize the servo hydraulic oil in the control plunger cavity and push the opening-closing plunger (2) to move downward, such that opening or closing of a lower end oil channel of the opening-closing plunger (2) is achieved to control fuel injection. The fuel injector effectively achieves a fast response and stable operational performance, and at the same time, the portions for electronic control and fuel injection are provided independent from each other to realize modularization for the entire fuel injector, thus facilitating maintenance and repair.

Description

Marine diesel injector

Technical field

The invention belongs to the field of engine design and relates to an injector, in particular to an external solenoid valve piston opening and closing injector for use on a marine diesel engine.

Background technique

The injector of the fuel injection device, which is a key component of the diesel engine, has been developed into the current electronically controlled injector, which has higher requirements on the control accuracy of injection timing, fuel injection law and fuel injection quantity, and the manufacturing precision requirements of the components. And the injector has higher requirements for the suitability of different oils.

At present, the common electromagnet and the needle valve coupler are commonly used, and the common rail injector structure for injecting and discharging through the needle valve is difficult to manufacture, sensitive to oil, and the injector is low in modularity and difficult to maintain. Poor interchangeability.

Summary of the invention

OBJECT OF THE INVENTION In order to overcome the deficiencies in the prior art, the present invention provides a marine diesel injector that effectively achieves rapid response and stable performance, while the electronic control and fuel injection portions are independent of each other, and the entire injector is realized. Modular, so maintenance and repair is convenient.

Technical Solution: In order to solve the above technical problem, a marine diesel injector of the present invention comprises a body, a piston assembly and a solenoid valve control module;

The upper part of the body is provided with a solenoid valve control module, and the upper part is further provided with a high-pressure oil pipe interface for receiving high-pressure fuel. The high-pressure oil pipe connection communicates with the inner hole of the mounting body located in the body, and the inner hole of the mounting seat is connected with the first oil passage. a groove is arranged in a lower part of the inner body, and a piston assembly is installed in the groove;

The piston assembly includes an opening and closing piston, an opening and closing piston rod and a fuel injector, wherein the opening and closing piston has a piston body on the upper and lower sides and a cylindrical structure in the middle portion, and the opening and closing piston rod is thin at the upper end and thick at the lower end, and is opened and closed. The piston and the inner wall of the groove of the body form an outer piston cavity, and the opening and closing piston and the opening and closing piston rod form an inner piston cavity, and the outer piston cavity communicates with the high pressure oil pipe through the first oil passage, and is provided on the cylindrical structure of the opening and closing piston The oil hole of the oil inlet, the inner piston cavity communicates with the outer piston cavity through the oil hole, the fuel injection nozzle is located at the lower end of the opening and closing piston, and the fuel injection nozzle is provided with an oil injection hole;

The solenoid valve control module includes an external solenoid valve, a mounting base and a control piston. The external solenoid valve is connected to the body through a mounting base, the control piston is located in the mounting base, and an oil storage chamber is arranged at an upper portion of the body. The piston rod of the control piston is inserted into the oil storage chamber, and the liquid in the oil storage chamber flows into the top end of the opening and closing piston through the third oil passage.

Preferably, the body is provided with a fuel leakage hole, and the fuel leakage hole communicates with the second oil passage communicating with the outside, the first oil passage intersects with the second oil passage, and the inner hole of the mounting seat is tapered. The fuel leakage hole communicates with the outside world. After the fuel enters through the horizontal hole, it will only flow downward due to the pressure, and its liquid level will not exceed the height of the horizontal hole. (Connector principle: the liquid level of the pipe connected to the air Not higher than the level of the horizontal pipe); but in the case of oil return, The opposite is true. When the fuel returns to the intersection of the horizontal hole and the vertical hole, it can flow out from the hole that is in contact with the air to complete the leak.

Preferably, the body is provided with an upper oil passage communicating with the oil storage chamber, and the top end of the upper oil passage is provided with an external servo hydraulic system.

Preferably, the installation base is provided with a leakage oil return port communicating with the control piston.

Preferably, an adjustment pad for adjusting the volume of the reservoir chamber is mounted between the mounting base and the body.

The body of the invention receives the high-pressure fuel through the high-pressure oil pipe and reaches the opening and closing piston cavity through the internal oil passage, and the high-pressure servo hydraulic oil reaches the control piston cavity through the internal oil passage, the high-pressure fuel pressure is slightly larger than the high-pressure servo hydraulic oil pressure, and the high-pressure fuel oil The combination of pressure and hydraulic servo hydraulic oil pressure, the opening and closing piston stops at the top dead center, and the control port of the external solenoid valve changes the oil circuit of the high pressure or low pressure to change the oil pressure of the control room. And controlling the downward stroke of the piston, thereby compressing the servo hydraulic oil of the control piston chamber, pushing the opening and closing piston to travel downward, thereby realizing the opening and closing of the lower end oil passage of the opening and closing piston to achieve the fuel injection control.

The invention adopts the opening and closing piston assembly instead of the needle valve coupling member, realizes the hydraulic opening and closing of the injector, and combines with the external electromagnetic control to realize the modular structure and the multiple injection, and has the performance stability and the processing precision requirement. Low, easy maintenance and adaptability to fuel quality changes, especially suitable for medium and low speed marine high power diesel engines.

Advantageous Effects: The marine diesel injector of the present invention combines the high flow rate and high response speed controlled by an external solenoid valve with the high suitability and low manufacturing difficulty of the heavy duty oil of the piston open/close injector, and effectively realizes rapid response. The work performance is stable, and the electronic control and fuel injection parts are independent of each other, and the entire injector is modularized, so that maintenance and repair are convenient.

DRAWINGS

Figure 1 is a schematic view of the structure of the present invention;

Fig. 2 is a schematic view showing the state after the downward movement of the present invention.

detailed description

As shown in Figures 1 and 2, the marine diesel injector of the present invention includes a body 1, a piston assembly and a solenoid valve control module. The upper portion of the body 1 is provided with a high pressure oil pipe connection 13 and a mounting seat 11, and the high pressure oil pipe connection 11 is connected to an external high pressure oil pipe to receive high pressure fuel from a high pressure oil pump or a high pressure fuel common rail system. The mounting seat 11 is connected to the high-pressure oil pipe port 13 and has an oil hole, that is, an inner hole of the mounting seat. The oil hole is tapered, and is in contact with the interface of the high-pressure oil pipe and is sealed, and the oil hole is connected with the first oil passage. At the same time, the body 1 is provided with a fuel leakage hole 12, the fuel leakage hole is connected with the second oil passage communicating with the outside, the first oil passage intersects with the second oil passage, and the fuel leakage hole 12 is connected with the high pressure common rail system or the high pressure oil pump. In the case that the injector 4 has oil returning, the fuel can be leaked to avoid fuel leakage to the injector 4 elsewhere, which affects the working efficiency of the injector 4.

The piston assembly is disposed at a lower portion of the body 1 and includes an opening and closing piston 2, an opening and closing piston rod 3, and a fuel injector 4. The opening and closing piston 2 is provided with an upper and lower piston body, and the intermediate portion has a cylindrical structure for connection. The opening and closing piston 2 and the lower portion of the body 1 form an outer piston chamber 6, and the high pressure fuel enters the outer piston chamber 6 through the first oil passage of the body; the inner piston chamber 5 is formed between the opening and closing piston 2 and the piston rod 3, and the piston 2 is opened and closed. The middle cylinder is provided with oil holes for oil supply. The injector 4 is connected to a lower end of the opening and closing piston 2. The opening and closing piston 2 slides downward along the opening and closing piston rod 3, and the outer piston chamber 6 communicates with the oil hole of the fuel injector 4. When the outer piston chamber 6 communicates with the oil hole of the injector 4, the fuel in the outer piston chamber 6 enters the nozzle 4 to effect fuel injection. As the opening and closing piston 2 slides downward, the oil hole on the middle cylinder of the opening and closing piston 2 is closed by the lower end of the opening and closing piston rod 3. As shown in Fig. 2, the inner piston chamber 5 is disconnected from the outer piston chamber 6 to form a closed space. . As the opening and closing piston 2 moves downward, the oil pressure of the inner piston chamber 5 continues to increase, forming a certain level of high-pressure fuel, and the opening and closing piston 2 has an upward movement tendency under the action of its oil pressure. When the oil pressure in the inner piston chamber 5 is sufficient to overcome the pressure applied to the upper end of the opening and closing piston 2, the opening and closing piston 2 moves up until the outer piston chamber 6 is disconnected from the injector oil hole, and the fuel injection is stopped. At the same time, the inner piston chamber 5 communicates with the outer piston chamber 6, and the opening and closing piston 2 is reset by the action of pressure.

The solenoid valve control module is mounted on the top of the body 1, and includes an external solenoid valve 8, a mounting base 10, an adjustment washer 7, an external servo hydraulic system 15, and a control piston 9, the external solenoid valve 8 Mounted on the body 1 by a mounting base 10, the mounting base 10 is fixed to the body 1 by screws, the control piston 9 is placed in the inner cavity of the mounting base 10, and the bottom of the control piston 9 An oil storage chamber is formed between the end and the body 1, and the external servo hydraulic system 15 controls the pressure of the servo hydraulic oil entering the oil storage chamber through the upper oil passage of the body 1, the adjusting gasket 7 clamp It is placed between the mounting base 10 and the body 1, and the volume of the oil storage chamber is adjusted by changing the thickness. The left side of the mounting base 10 is provided with a leaking oil return port 14 for discharging the leaked control oil to prevent the oil from entering the lower oil storage chamber. The servo hydraulic oil pressure in the oil storage chamber is equal to the fuel pressure in the outer piston chamber 6, so that the opening and closing piston 2 is maintained in an equilibrium state. The external solenoid valve 8 receives the external control signal, changes the stroke of the control piston 9, controls the servo hydraulic oil entering the oil storage chamber to flow to the upper end chamber of the opening and closing piston 2, and pushes the opening and closing piston 2 to move downward.

The specific working process of the present invention is as follows: when the external solenoid valve 8 is not energized, its internal control port is connected to the low pressure servo oil, and the control piston 9 is subjected to an upward servo oil pressure greater than that from the control chamber of the external solenoid valve 8 Under the servo oil pressure, the control piston 9 is kept in a stationary state, and the injector 4 is not sprayed. When the external solenoid valve 8 receives the control signal of the electronic control unit and is energized, its internal control port is quickly switched to the high-pressure servo oil, and the servo oil in the control chamber pushes the control piston 9 downward to push the servo oil in the oil storage chamber into the opening and closing. The upper end chamber of the piston 2 pushes the opening and closing piston 2 downward, so that the outer piston chamber 6 is connected to the fuel injector 4, and the fuel injector 4 realizes fuel injection. As the opening and closing piston 2 moves downward, the oil pressure of the inner piston chamber 5 continues to increase, forming a certain level of high-pressure fuel, and the opening and closing piston 2 has an upward movement tendency under the action of its oil pressure. When the oil pressure in the inner piston chamber 5 is sufficient to overcome the pressure applied to the upper end of the opening and closing piston 2, the opening and closing piston 2 moves up until the outer piston chamber 6 is disconnected from the injector oil hole, and the fuel injection is stopped. At the same time, the inner piston chamber 5 and outside The piston chamber 6 is connected, and the opening and closing piston 2 is reset by the action of pressure. By precisely arranging the oil hole size in the middle of the cylinder of the opening and closing piston 2, that is, its relative position with the oil hole of the fuel injector 4, and the volume and shape of the oil storage chamber, the injector can be realized under the rapid switching of the electromagnetic valve 8. The rapid movement of the opening and closing piston 2 enables a flexible injection mode and real-time adjustment. The above description is only a preferred embodiment of the present invention, and it should be noted that those skilled in the art can also make several improvements and retouchings without departing from the principles of the present invention. It should be considered as the scope of protection of the present invention.

Claims

A marine diesel injector, comprising: a body, a piston assembly and a solenoid valve control module;

The upper part of the body is provided with a solenoid valve control module, and the upper part is further provided with a high-pressure oil pipe interface for receiving high-pressure fuel. The high-pressure oil pipe connection communicates with the inner hole of the mounting body located in the body, and the inner hole of the mounting seat is connected with the first oil passage. a groove is arranged in a lower part of the inner body, and a piston assembly is installed in the groove;

The piston assembly includes an opening and closing piston, an opening and closing piston rod and a fuel injector, wherein the opening and closing piston has a piston body on the upper and lower sides and a cylindrical structure in the middle portion, and the opening and closing piston rod is thin at the upper end and thick at the lower end, and is opened and closed. The piston and the inner wall of the groove of the body form an outer piston cavity, and the opening and closing piston and the opening and closing piston rod form an inner piston cavity, and the outer piston cavity communicates with the high pressure oil pipe through the first oil passage, and is provided on the cylindrical structure of the opening and closing piston The oil hole of the oil inlet, the inner piston cavity communicates with the outer piston cavity through the oil hole, the fuel injection nozzle is located at the lower end of the opening and closing piston, and the fuel injection nozzle is provided with an oil injection hole;

The solenoid valve control module includes an external solenoid valve, a mounting base and a control piston. The external solenoid valve is connected to the body through a mounting base, the control piston is located in the mounting base, and an oil storage chamber is arranged at an upper portion of the body. The piston rod of the control piston is inserted into the oil storage chamber, and the liquid in the oil storage chamber flows into the top end of the opening and closing piston through the third oil passage.
The marine diesel fuel injector according to claim 1, wherein the body is provided with a fuel leakage hole, and the fuel leakage hole communicates with a second oil passage communicating with the outside, and the first oil passage intersects with the second oil passage. The inner hole of the mounting seat is tapered.
The marine diesel fuel injector according to claim 1, wherein the body is provided with an upper oil passage communicating with the oil storage chamber, and an upper servo oil system is disposed at a top end of the upper oil passage.
The marine diesel fuel injector according to claim 3, wherein the mounting base is provided with a leaking oil return port that communicates with the control piston.
The marine diesel fuel injector according to claim 4, wherein an adjusting gasket for adjusting a volume of the oil storage chamber cavity is mounted between the mounting base and the body.