A dual fuel injector for diesel and alternative fuels with a closed needle valve body

Abstract

The application aims to provide a cylinder high-pressure direct injection dual fuel nozzle with a closed needle valve body and integrated diesel and alternative fuel, belonging to the field of engine fuel injection. When the high-pressure control oil in the diesel control chamber flows out of the low-pressure area through the diesel control oil inlet hole and the pressure decreases, the high-pressure diesel from the diesel inlet hole drives the diesel needle valve to overcome the spring force of the diesel valve spring and lift up, and then the diesel is injected through the diesel injection hole. When the high-pressure control oil in the alternative fuel control chamber flows out of the low-pressure area through the alternative fuel control oil inlet hole and the pressure decreases, the high-pressure alternative fuel from the alternative fuel inlet hole drives the alternative fuel needle valve and diesel needle valve body to overcome the spring force of the alternative fuel valve spring and lift up, and then the alternative fuel is injected through the alternative fuel injection hole and the diesel injection hole. The application is suitable for various alternative fuels, the atomization field is uniform, is not disturbed by the cylinder pressure, the injection is stable, the linear gain of the injection amount is better, and the application has the characteristics of high reliability, low cost and the like.

Description

Technical Field

[0001] The present invention relates to an engine fuel injection system, specifically a nozzle. Background Technology

[0002] Due to their structural complexity, most integrated diesel and alternative fuel injection systems currently employ port injection. In-cylinder high-pressure, direct injection dual-fuel technology is still immature and exhibits some performance and reliability issues. Figure 2The existing in-cylinder high-pressure, direct-injection dual-fuel nozzle consists of a body 8, a substitute fuel needle valve body 9, a substitute fuel valve spring 11, a sealing bolt 12, a substitute fuel needle valve / diesel needle valve body 13, a diesel valve spring 14, a diesel needle valve 15, and a guide steel ball 16. In the existing technology, the body 8 and the substitute fuel needle valve body 9 are fixedly connected together, providing the nozzle with high-pressure diesel, substitute fuel, and the necessary control oil. A conical seat surface is formed in the lower part of the cavity of the substitute fuel needle valve body 9, and two stepped cylindrical holes are concentrically formed below the conical seat surface. A set of 902 substitute fuel injection holes is formed at the first cylindrical hole. A substitute fuel needle valve sealing line 134 is formed on the upper section of the outer conical surface at the lower end of the substitute fuel needle valve / diesel needle valve body 13. Below the outer conical surface where the substitute fuel needle valve sealing line 134 is located, a reverse conical surface is connected, and below that, a cylinder 133 is formed. The cylinder 133 is inserted into the cylindrical hole at the lower end of the substitute fuel needle valve body 9. The first cylindrical hole at the lower part of the cavity of the substitute fuel needle valve body 9 below the substitute fuel needle valve sealing line 134, together with the cavity under the jurisdiction of the substitute fuel needle valve / diesel needle valve body 13, constitutes a substitute fuel pressure chamber 904. A conical hole seat surface is formed at the lower end of the inner cavity of the substitute fuel needle valve / diesel needle valve body 13. Below the conical hole seat surface, a bladder-shaped cavity is formed, and a set of diesel injection holes 903 are formed in this cavity. A diesel needle valve sealing line 153 formed by a double cone shape is formed at the lower end of the diesel needle valve 15. The diesel needle valve sealing line 153 and the cavity governed by the substitute fuel needle valve / diesel needle valve body 13 constitute the diesel pressure chamber 132. When control oil flows from the diesel control oil inlet 804 to the low-pressure area, the high-pressure diesel from the diesel inlet 803 exerts an upward force on the diesel needle valve 15, overcoming the spring force of the diesel valve spring 14, and the diesel is ejected outward through the diesel injection port 903. When control oil flows from the substitute fuel control oil inlet 802 to the low-pressure area, the high-pressure substitute fuel from the substitute fuel inlet 801 exerts an upward force on the substitute fuel needle valve / diesel needle valve body 13, overcoming the spring force of the substitute fuel valve spring 11, and the substitute fuel is ejected outward through the substitute fuel injection port 902. When both the substitute fuel control oil inlet 802 and the diesel control oil inlet 804 are under high pressure, the substitute fuel needle valve sealing line 134 is closed by fitting with the conical seat surface at the lower part of the substitute fuel needle valve body 9. At the same time, the diesel needle valve sealing line 153 is closed by fitting with the conical seat surface at the lower end of the inner cavity of the substitute fuel needle valve and diesel needle valve body 13, and both sets of injections stop.

[0003] like Figure 2The deficiency of the prior art nozzle shown is that the positioning of the substitute fuel needle valve / diesel needle valve body 13 is affected by three sets of mating relationships, including: the upper mating stage, the lower substitute fuel needle valve sealing line, and the mating between the cylinder 133 of the substitute fuel needle valve / diesel needle valve body 13 and the cylindrical hole at the lower end of the substitute fuel needle valve body 9. These three mating relationships are actually in an over-positioning state. To solve the over-positioning problem, one of the three mating pairs must be selected, and its mating clearance enlarged to compensate for the errors of the other two pairs. Analyzing the importance of the three mating pairs reveals that: firstly, the mating stage of the upper substitute fuel needle valve / diesel needle valve body 13 and the mating between the lower substitute fuel needle valve sealing line must meet the sealing requirements. Comparatively, the only compromise that can be made is to enlarge the mating clearance between the cylinder 133 of the substitute fuel needle valve / diesel needle valve body 13 and the cylindrical hole at the lower end of the substitute fuel needle valve body 9. However, the enlarged fit clearance results in the following: during substitute fuel injection, the substitute fuel will form an annular jet along the fit clearance between the cylinder 133 of the substitute fuel needle valve / diesel needle valve body 13 and the cylindrical hole at the lower end of the substitute fuel needle valve body 9, thereby altering the concentration field distribution of the substitute fuel in the combustion chamber. Furthermore, when diesel injection and substitute fuel injection occur simultaneously, this annular jet will obstruct the ignition of the diesel spray, confining a portion of the diesel spray within the space covered by the annular jet, thus affecting the ignition effect.

[0004] Furthermore, the flow rate of the annular jet generated by the annular gap: In the formula: The flow rate of the annular jet, The diameter of cylinder 133, Average gap, kinetic viscosity Matching length, Relative eccentricity, pressure difference As can be seen from the above formula, besides the gap between the cylindrical body 133 and the cylindrical hole corresponding to the alternative fuel needle valve body 9 and the annular jet flow rate... In addition to the influence of relative eccentricity The variations in jet volume caused by these factors also have a significant impact on product consistency. Reducing the dispersion of the annular jet's flow requires improving processing precision, which obviously leads to increased costs.

[0005] like Figure 2The shortcomings of the existing nozzle shown also lie in the fact that a large surface area of ​​the lower end of the cylindrical head 133 of the alternative fuel needle valve body 9 is directly exposed inside the engine cylinder. The engine's combustion pressure can reach 140 bar or even higher. Under the action of this cylinder combustion pressure, the alternative fuel needle valve / diesel needle valve body 13 is subjected to an upward force of up to 260 N or even greater. This upward force obstructs the closing of the alternative fuel needle valve / diesel needle valve body 13, or even prevents it from closing in time, leading to a surge in injection volume for that cycle. Since the nozzle control is in a closed-loop state at this time, this results in a sharp decrease in injection volume for the next cycle. This repeated process causes significant oscillations in engine torque.

[0006] The large head of the cylindrical body 133 at the front end of the alternative fuel needle valve / diesel needle valve body 13 is exposed inside the engine cylinder, generating an upward force of up to 260N or even greater. This necessitates the use of a high-stiffness alternative fuel valve spring 11 to balance the force. As a result, while meeting the spring force requirements under large pulse widths, the impact on the cone hole seat surface of the alternative fuel needle valve body 9 is increased when the alternative fuel needle valve / diesel needle valve body 13 is seated, seriously affecting the product's durability.

[0007] Furthermore, the large head of the cylindrical part 133 at the front end of the alternative fuel needle valve / diesel needle valve body 13 is exposed inside the engine cylinder. Due to its large diameter and large heating area, the exposed surface of the alternative fuel needle valve / diesel needle valve body 13, which should be well cooled by being covered in fuel, is heated by the high-temperature combustion gas inside the cylinder. This heats the unburned fuel adhering to the outer surface of the alternative fuel needle valve / diesel needle valve body 13 to a temperature that causes coking, carbonization, and carbon deposit formation, or even higher temperatures, affecting the reliability of the nozzle. Summary of the Invention

[0008] The purpose of this invention is to provide a highly reliable, low-cost in-cylinder high-pressure direct injection dual-fuel nozzle with a closed needle valve body that integrates diesel and alternative fuels, suitable for various alternative fuels including gaseous and liquid fuels, with uniform atomization field, unaffected by cylinder pressure, stable injection, and better linearity of injection quantity gain.

[0009] The objective of this invention is achieved as follows: This invention discloses an in-cylinder high-pressure direct injection dual-fuel nozzle with a sealed needle valve body and integrated diesel and alternative fuels. Its features include: a main body, an alternative fuel needle valve body, a sealing bolt, a diesel needle valve, and an alternative fuel needle valve / diesel needle valve body. The main body is fixed to the alternative fuel needle valve body. The bottom of the alternative fuel needle valve body has both an alternative fuel injection hole and a diesel injection hole. The alternative fuel needle valve / diesel needle valve body is installed inside the alternative fuel needle valve body. The upper part of the sealing bolt is located inside the main body, and its lower part is installed inside the alternative fuel needle valve / diesel needle valve body. The diesel needle valve is installed inside the alternative fuel needle valve / diesel needle valve body. The bottom of the substitute fuel needle valve / diesel needle valve body is provided with a diesel pressure chamber that communicates with the diesel injection port. A substitute fuel storage chamber and a substitute fuel pressure chamber are formed between the substitute fuel needle valve body and the substitute fuel needle valve / diesel needle valve body. The substitute fuel pressure chamber communicates with the substitute fuel injection port. A diesel storage chamber is formed between the diesel needle valve and the substitute fuel needle valve / diesel needle valve body. The bottom of the diesel needle valve cooperates with the substitute fuel needle valve / diesel needle valve body to control the opening and closing of the diesel storage chamber and the diesel pressure chamber. The substitute fuel needle valve / diesel needle valve body cooperates with the substitute fuel needle valve body to control the opening and closing of the substitute fuel storage chamber and the substitute fuel pressure chamber.

[0010] The present invention may also include: 1. A substitute fuel control chamber is formed between the top of the sealing bolt and the main body. A substitute fuel valve spring is installed in the substitute fuel control chamber. The diesel needle valve, sealing bolt, and substitute fuel needle valve / diesel needle valve body form a diesel control chamber. A diesel valve spring is installed in the diesel control chamber. Diesel inlet, diesel control oil inlet, substitute fuel control oil inlet, and substitute fuel inlet are respectively opened on the main body. The diesel inlet connects to the diesel storage chamber. The diesel control oil inlet connects to the diesel control chamber. The substitute fuel control oil inlet connects to the substitute fuel control chamber. The substitute fuel inlet connects to the substitute fuel storage chamber.

[0011] 2. A diesel fuel passage is provided in the middle of the diesel needle valve, and the diesel fuel inlet is connected to the diesel fuel storage chamber through the diesel fuel passage.

[0012] 3. The substitute fuel needle valve and diesel needle valve body are completely enclosed in the cavity of the substitute fuel needle valve body.

[0013] 4. When injecting diesel fuel, the high-pressure control oil in the diesel control chamber flows from the diesel control oil inlet to the low-pressure area. The high-pressure diesel fuel for injection from the diesel inlet enters the diesel storage chamber and lifts the diesel needle valve upward against the spring force of the diesel valve spring. The diesel fuel is then sprayed outward from the diesel injection hole through the diesel storage chamber.

[0014] 5. When injecting substitute fuel, the high-pressure control oil in the substitute fuel control chamber flows to the low-pressure area through the substitute fuel control oil inlet. The high-pressure substitute fuel from the substitute fuel inlet enters the substitute fuel storage chamber and lifts the substitute fuel needle valve / diesel needle valve body upward against the spring force of the substitute fuel valve spring. The substitute fuel is then sprayed outward together through the substitute fuel injection hole and the diesel injection hole.

[0015] 6. When fuel injection stops, the high-pressure fuel entering the substitute fuel control chamber and the diesel fuel control chamber through the substitute fuel control oil inlet and the diesel control oil inlet, respectively, re-establishes high pressure and acts on the substitute fuel needle valve and the diesel needle valve. The part of the substitute fuel needle valve / diesel needle valve body located above the substitute fuel pressure chamber is attached to the substitute fuel needle valve body, and the diesel needle valve is attached to the conical seat surface made at the lower end of the substitute fuel needle valve / diesel needle valve body.

[0016] The advantages of this invention are: 1. The substitute fuel injection orifice 202 and the diesel fuel injection orifice 203 are both arranged on the substitute fuel needle valve body 2, and can complete the separate and precise injection of diesel fuel and substitute fuel. 2. The alternative fuel injection port 202 and the diesel injection port 203 are both arranged on the alternative fuel needle valve body 2, which not only eliminates the complicated process of opening the guide groove of the alternative fuel needle valve body 2, but also increases the sealing length of the components, thereby reducing leakage.

[0017] 3. The substitute fuel nozzle 202 and the diesel nozzle 203 are both arranged on the substitute fuel needle valve body 2. The substitute fuel is sprayed through the substitute fuel nozzle 202 and the diesel nozzle 203. The included angle between each nozzle remains unchanged, so that the substitute fuel spray distribution is more uniform.

[0018] 4. The substitute fuel injection hole 202 and the diesel injection hole 203 are both arranged on the substitute fuel needle valve body 2. When the substitute fuel is injected, the substitute fuel injection hole 202 and the diesel injection hole 203 inject the substitute fuel together, which has a better cooling effect on the part of the substitute fuel needle valve and diesel needle valve body 5 that extends into the cylinder, and helps to avoid coking and carbon deposits.

[0019] 5. The substitute fuel needle valve / diesel needle valve body 5 is completely enclosed in the cavity at the lower end of the substitute fuel needle valve body 2, thereby protecting the substitute fuel needle valve / diesel needle valve body 5 from the erosion of the high temperature and high pressure combustion gas in the cylinder, greatly improving the reliability of the nozzle. Attached Figure Description

[0020] Figure 1 This is a schematic diagram of the structure of the present invention; Figure 2 This is a schematic diagram of the existing technology.

[0021] Figure reference numerals: 1. Main body; 2. Alternative fuel needle valve body; 3. Alternative fuel valve spring; 4. Sealing bolt; 5. Alternative fuel needle valve / diesel needle valve body; 6. Diesel valve spring; 7. Diesel needle valve; 8. Main body; 9. Alternative fuel needle valve body; 11. Alternative fuel valve spring; 12. Sealing bolt; 13. Alternative fuel needle valve / diesel needle valve body; 14. Diesel valve spring; 15. Diesel needle valve; 16. Guide steel ball; 101. Alternative fuel inlet; 102. Alternative fuel control oil inlet; 103. Diesel inlet; 104. Diesel control oil inlet; 105. Alternative fuel control chamber; 201. Alternative fuel storage chamber; 202. Alternative fuel nozzle; 203. Diesel nozzle; 204. Alternative fuel pressure chamber; 501. Diesel storage chamber; 502. Diesel pressure chamber, 503 substitute fuel needle valve sealing line, 504 fuel isolation sealing line, 701 dynamic seal diameter, 702 diesel through groove, 703 diesel needle valve sealing line, 704 diesel control chamber, 801 substitute fuel inlet, 802 substitute fuel control oil inlet, 803 diesel inlet, 804 diesel control oil inlet, 805 substitute fuel control chamber, 901 substitute fuel storage chamber, 902 substitute fuel nozzle, 903 diesel nozzle, 904 substitute fuel pressure chamber, 131 diesel storage chamber, 132 diesel pressure chamber, 133 cylinder, 134 substitute fuel needle valve sealing line, 151 dynamic seal diameter, 152 diesel through groove, 153 diesel needle valve sealing line, 154 diesel control chamber. Detailed Implementation

[0022] The invention will now be described in more detail with reference to the accompanying drawings: Combination Figure 1-2The present invention includes: a body 1, a substitute fuel needle valve body 2, a substitute fuel valve spring 3, a positioning bolt 4, a substitute fuel needle valve / diesel needle valve body 5, a diesel valve spring 6, and a diesel valve core 7. The body 1 and the substitute fuel needle valve body 2 are concentrically fixed together. The substitute fuel injection port 202 and the diesel injection port 203 are both arranged on the substitute fuel needle valve body 2. The substitute fuel needle valve / diesel needle valve body 5 is completely enclosed in the cavity at the lower end of the substitute fuel needle valve body 2, thereby preventing the substitute fuel needle valve / diesel needle valve body 5 from being corroded by the high temperature and high pressure combustion gas of the cylinder. A conical seat surface is formed in the lower part of the cavity of the alternative fuel needle valve body 2. A groove divides the conical seat surface 54 into two sections in the middle of the conical seat surface. The upper section of the conical seat surface and the alternative fuel needle valve sealing line of the alternative fuel needle valve / diesel needle valve body 5 constitute the switch for alternative fuel. A set of alternative fuel injection holes 202 is formed in the groove at the lower part of the cavity of the alternative fuel needle valve body 2. The conical seat surface below the groove and the fuel isolation sealing line 504 of the alternative fuel needle valve / diesel needle valve body 5 function to isolate diesel fuel from alternative fuel. A set of diesel injection holes 203 is formed in the capsule cavity below the conical seat surface at the lower end of the alternative fuel needle valve body 2. The space governed by the alternative fuel needle valve sealing line 503 and the fuel isolation sealing line 504 constitutes the alternative fuel pressure chamber 204, and the space governed by the diesel needle valve sealing line 703 and the fuel isolation sealing line 504 constitutes the diesel pressure chamber 502.

[0023] The alternative fuel injection orifice 202 and the diesel fuel injection orifice 203 are both arranged on the alternative fuel needle valve body 2, which can complete the individual and precise injection of diesel fuel and alternative fuel. The substitute fuel nozzle 202 and the diesel nozzle 203 are both arranged on the substitute fuel needle valve body 2. The substitute fuel is sprayed through the substitute fuel nozzle 202 and the diesel nozzle 203. The included angle between each nozzle remains unchanged, so that the substitute fuel spray distribution is more uniform.

[0024] The substitute fuel injection port 202 and the diesel injection port 203 are both arranged on the substitute fuel needle valve body 2. When the substitute fuel is injected, the substitute fuel injection port 202 and the diesel injection port 203 inject the substitute fuel together, which has a better cooling effect on the part of the substitute fuel needle valve / diesel needle valve body 5 that extends into the cylinder, and helps to avoid coking and carbon deposits.

[0025] The substitute fuel needle valve / diesel needle valve body 5 is completely enclosed in the cavity at the lower end of the substitute fuel needle valve body 2, thereby protecting the substitute fuel needle valve / diesel needle valve body 5 from the erosion of the high temperature and high pressure combustion gas in the cylinder, greatly improving the reliability of the nozzle.

[0026] During diesel injection, the control signal opens the diesel control valve, requiring the high-pressure diesel in the diesel control chamber 704 to be depressurized. At this time, the high-pressure control oil in the diesel control chamber 704 flows from the diesel control oil inlet 104 to the low-pressure area. The high-pressure diesel for injection from the diesel inlet 103 enters the diesel storage chamber 501, lifting the diesel needle valve 7 against the spring force of the diesel valve spring 6. The diesel is then ejected from the diesel injection port 203 through the diesel storage chamber 501. During alternative fuel injection, the control signal opens the alternative fuel control valve, requiring the high-pressure control diesel in the alternative fuel control chamber 105 to be depressurized. At this time, the high-pressure control oil in the alternative fuel control chamber 105 flows from the alternative fuel control oil inlet 102 to the low-pressure area. High-pressure substitute fuel from the substitute fuel inlet 101 enters the substitute fuel storage chamber 201. The upward force on the substitute fuel needle valve / diesel needle valve body 5 overcomes the spring force of the substitute fuel valve spring 3, lifting it upward. The substitute fuel is then sprayed outward through the substitute fuel injection port 202 and the diesel injection port 203. When fuel injection stops, the control signal is closed, the fuel control valve leakage is closed, and the high-pressure fuel entering the substitute fuel control chamber 105 and the diesel fuel control chamber 704 through the substitute fuel control oil inlet 102 and the diesel control oil inlet 104 respectively re-establishes high pressure, acting on the substitute fuel needle valve 5 and the diesel needle valve 7. The substitute fuel needle valve sealing line 503 is sealed and closed by the conical seat surface at the lower part of the cavity of the substitute fuel needle valve body 2. At the same time, the diesel needle valve sealing line 703 is sealed and closed by the conical seat surface at the lower end of the inner cavity of the substitute fuel needle valve / diesel needle valve body 5. Both sets of injections stop.

Claims

1. A dual-fuel nozzle with a closed needle valve body and integrated diesel and alternative fuel, characterized in that: The system includes a main body, a substitute fuel needle valve body, a sealing bolt, a diesel needle valve, and a substitute fuel needle valve / diesel needle valve body. The main body is fixed to the substitute fuel needle valve body. The bottom of the substitute fuel needle valve body has both a substitute fuel injection port and a diesel fuel injection port. The substitute fuel needle valve / diesel needle valve body is installed inside the substitute fuel needle valve body. The upper part of the sealing bolt is located inside the main body, and its lower part is installed inside the substitute fuel needle valve / diesel needle valve body. The diesel needle valve is installed inside the substitute fuel needle valve / diesel needle valve body. The bottom of the substitute fuel needle valve / diesel needle valve body is connected to the diesel fuel needle valve body. The diesel pressure chamber is connected to the fuel injection port. The substitute fuel needle valve body and the substitute fuel needle valve / diesel needle valve body form a substitute fuel storage chamber and a substitute fuel pressure chamber. The substitute fuel pressure chamber is connected to the substitute fuel injection port. The diesel needle valve and the substitute fuel needle valve / diesel needle valve body form a diesel storage chamber. The bottom of the diesel needle valve cooperates with the substitute fuel needle valve / diesel needle valve body to control the opening and closing of the diesel storage chamber and the diesel pressure chamber. The substitute fuel needle valve / diesel needle valve body cooperates with the substitute fuel needle valve body to control the opening and closing of the substitute fuel storage chamber and the substitute fuel pressure chamber.

2. The in-cylinder high-pressure direct injection dual-fuel nozzle with a sealed needle valve body and integrated diesel and alternative fuel as described in claim 1, characterized in that: A substitute fuel control chamber is formed between the top of the sealing bolt and the main body. A substitute fuel valve spring is installed in the substitute fuel control chamber. The diesel needle valve, the sealing bolt, and the substitute fuel needle valve / diesel needle valve body form a diesel control chamber. A diesel valve spring is installed in the diesel control chamber. Diesel inlet, diesel control oil inlet, substitute fuel control oil inlet, and substitute fuel inlet are respectively opened on the main body. The diesel inlet connects to the diesel storage chamber. The diesel control oil inlet connects to the diesel control chamber. The substitute fuel control oil inlet connects to the substitute fuel control chamber. The substitute fuel inlet connects to the substitute fuel storage chamber.

3. The in-cylinder high-pressure direct injection dual-fuel nozzle with a sealed needle valve body and integrated diesel and alternative fuel as described in claim 1, characterized in that: The diesel needle valve has a diesel passage groove in the middle, and the diesel inlet hole is connected to the diesel storage chamber through the diesel passage groove.

4. A dual-fuel nozzle with a sealed needle valve body and integrated diesel and alternative fuels, as described in claim 1, is characterized in that: The alternative fuel needle valve and diesel needle valve body are completely enclosed in the cavity of the alternative fuel needle valve body.

5. A dual-fuel nozzle with a closed needle valve body and integrated diesel and alternative fuels, as described in claim 1, is characterized in that: When diesel fuel is injected, the high-pressure control oil in the diesel control chamber flows from the diesel control oil inlet to the low-pressure area. The high-pressure diesel fuel for injection from the diesel inlet enters the diesel storage chamber and lifts the diesel needle valve upward against the spring force of the diesel valve spring. The diesel fuel is then sprayed outward from the diesel injection hole through the diesel storage chamber.

6. A dual-fuel nozzle with a closed needle valve body and integrated diesel and alternative fuels, as described in claim 1, is characterized in that: When injecting substitute fuel, the high-pressure control oil in the substitute fuel control chamber flows to the low-pressure area through the substitute fuel control oil inlet. The high-pressure substitute fuel from the substitute fuel inlet enters the substitute fuel storage chamber and lifts the substitute fuel needle valve / diesel needle valve body upward against the spring force of the substitute fuel valve spring. The substitute fuel is then sprayed outward together through the substitute fuel injection hole and the diesel injection hole.

7. A dual-fuel nozzle with a closed needle valve body and integrated diesel and alternative fuels, as described in claim 1, is characterized in that: When fuel injection stops, the high-pressure fuel entering the substitute fuel control chamber and the diesel fuel control chamber through the substitute fuel control oil inlet and the diesel control oil inlet, respectively, re-establishes high pressure and acts on the substitute fuel needle valve and the diesel needle valve. The part of the substitute fuel needle valve / diesel needle valve body located above the substitute fuel pressure chamber is attached to the substitute fuel needle valve body, and the diesel needle valve is attached to the conical seat surface made at the lower end of the substitute fuel needle valve / diesel needle valve body.

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