Double-fluid atomization injection system without independent air source supply device

Abstract

The invention belongs to the technical field of fuel atomization of an internal combustion engine, and particularly relates to a double-fluid atomization injection system without an independent gas source supply device, which comprises a control module, a waste gas circulation system and an air-assisted fuel injection device, and is characterized in that the waste gas circulation system comprises an exhaust passage, an exhaust pressure sensor, an injection pressure sensor and an EGR (Exhaust Gas Recirculation) valve; one end of the exhaust passage is used for being communicated with an exhaust system on the exhaust valve side of an engine, and the exhaust pressure sensor, the jet pressure sensor and the EGR valve are all installed on the exhaust passage. The air-assisted fuel injection device comprises a fuel inlet, an injection outlet and a premixing cavity, the fuel inlet and the injection outlet are communicated with the premixing cavity, and the end, away from the exhaust valve, of the exhaust passage is communicated to the premixing cavity; and the control module is electrically connected with the exhaust pressure sensor, the air injection pressure sensor and the air-assisted fuel injection device. The problem that an independent air source supply device needs to be externally connected in the air-assisted fuel injection technology of the aviation heavy oil engine is solved.

Description

Technical Field

[0001] The invention belongs to the technical field of fuel atomization of internal combustion engines, and in particular relates to a dual-fluid atomization injection system without an independent gas source supply device. Background Art

[0002] The atomization and clean combustion of fuel have become increasingly important as emission regulations become increasingly stringent, especially in the field of aviation piston engines. With the development trend of single fuel, heavy oil has attracted widespread attention due to its high energy density and high stability, and has become an important research direction in the field of aviation power. However, in high-altitude environments, the poor atomization of heavy oil and the difficulty in forming a mixture caused by low intake pressure and low intake temperature are bottleneck issues that restrict the development and application of aviation heavy oil piston engines. In order to achieve efficient atomization of heavy oil and precise control of the mixture in high-altitude environments, the air-assisted fuel injection (AAFI) technology based on the principle of dual-fluid atomization has attracted widespread attention and research.

[0003] AAFI uses compressed gas to promote the secondary breakage of fuel, and can obtain smaller spray particle size and spray penetration distance at a lower injection pressure. The spray particle size after atomization can be maintained within the order of 10μm, thereby avoiding the phenomenon of fuel wall adhesion while ensuring a good atomization level. This provides an effective way to solve the technical difficulties of heavy oil injection and improve the power and fuel utilization of aviation heavy oil piston engines. Current research on air-assisted injection technology has shown that the spray droplet size using AAFI is significantly smaller than that without AAFI, and AAFI can achieve micron-level atomization efficiency under heavy oil low-pressure injection.

[0004] Although air-assisted injection technology has good fuel atomization advantages, in actual applications, it requires an independent air supply device and a relatively complex and cumbersome structural design, which greatly increases the cost of the air-assisted fuel injection system and hinders its promotion and application in engineering. If the above problems are solved, it will not only promote the development of aviation piston engines, but also achieve new breakthroughs in vehicle power systems. Summary of the invention

[0005] The present invention is intended to provide a dual-fluid atomizing injection system without an independent air source supply device, so as to solve the problem that an external independent air source supply device is required in the air-assisted fuel injection technology of aviation heavy oil engines.

[0006] In order to achieve the above-mentioned object, the scheme of the present invention is: a dual-fluid atomization injection system without an independent air source supply device, including a control module, an exhaust gas circulation system and an air-assisted fuel injection device:

[0007] An exhaust gas circulation system, including an exhaust passage, an exhaust pressure sensor, an injection pressure sensor, and an EGR valve, wherein one end of the exhaust passage is used to be connected to the exhaust system on the exhaust valve side of the engine, and the exhaust pressure sensor, the injection pressure sensor, and the EGR valve are all installed on the exhaust passage, wherein the exhaust pressure sensor is located on the intake side of the EGR valve, and the injection pressure sensor is located on the exhaust side of the EGR valve;

[0008] The air-assisted fuel injection device comprises a fuel inlet, an injection outlet and a premixing chamber, wherein the fuel inlet and the injection outlet are connected to the premixing chamber, and an end of the exhaust passage away from the exhaust valve is connected to the premixing chamber;

[0009] The control module is electrically connected to the exhaust pressure sensor, the jet pressure sensor and the air-assisted fuel injection device.

[0010] The working principle of this scheme is as follows: the atomizing injection system starts from the scavenging process after the engine combustion. After the engine works, the piston moves upward, and the exhaust valve opens to compress the exhaust gas and discharge it from the exhaust duct. The exhausted exhaust gas is guided to the air-assisted fuel injection device through the EGR valve to act on the direct injection process of the fuel in the cylinder. The EGR valve can achieve different openings to control the exhaust gas pressure entering the air-assisted fuel injection device. The opening size depends on the pressure value detected by the jet pressure sensor. The monitored pressure value will be fed back to the control module, and the control module will control the opening size of the EGR valve according to the pressure value, thereby determining the amount of exhaust gas flowing into the air-assisted fuel injection device.

[0011] The beneficial effects of this solution are:

[0012] 1. Solved the atomization problem of aviation fuel:

[0013] First of all, the advantages of the air-assisted fuel injection device can promote the atomization, breakage and evaporation of high-density and high-kinematic viscosity heavy fuels. In the device of the present invention, by combining EGR with AAFI, the exhaust gas discharged after combustion in the engine is used as the compressed gas source for breaking and atomizing in the air-assisted fuel injection device. Compared with the use of traditional compressed gas, the use of exhaust gas recirculation can not only effectively reduce the emission problems in the engine combustion process, but also the interaction of the impact shear of the exhaust gas on the fuel spray can fully break the heavy oil into small droplet spray particles, and the high-temperature EGR exhaust gas can heat the fuel, effectively promoting the evaporation and diffusion of the fuel spray, so that it can form a high-quality homogeneous mixture in the cylinder, optimize the combustion process in the cylinder of the engine, and improve the energy utilization rate and engine thermal efficiency.

[0014] 2. Solve the configuration problem of air-assisted fuel injection device on aviation heavy oil piston engine at present stage: The present invention can effectively solve this problem, without adding additional independent air source supply device on aviation piston engine, and can be realized by introducing exhaust gas into air-assisted fuel injection device by using mature EGR technology. To a great extent, the stability and lightweight design of aviation heavy oil piston engine are guaranteed.

[0015] 3. Combine air-assisted fuel injection technology with engine exhaust gas recirculation technology (EGR); EGR high-temperature exhaust gas further promotes fuel atomization, reduces the amount of heat absorbed during the evaporation of fuel in the cylinder, accelerates the formation of the mixture, shortens the ignition delay period, and improves combustion efficiency.

[0016] Optionally, a pressure relief pipe is provided on the exhaust pipe, one end of which is connected to the exhaust pipe, and the connection point is located between the exhaust pressure sensor and the EGR valve, and a back pressure valve is installed on the other end of the pressure relief pipe. The function of the back pressure valve is to prevent the excessive pressure in the intake duct from causing the engine to exhaust and run abnormally. When the exhaust pressure sensor detects that the pressure is too high, the back pressure valve will open to relieve the pressure.

[0017] Optionally, a one-way valve is provided on one end of the exhaust pipe close to the air-assisted fuel injection device to prevent the oil-air mixture in the premixing chamber of the air-assisted fuel injection device from flowing back into the exhaust pipe.

[0018] Optionally, a pressure stabilizing chamber is provided between the jet pressure sensor and the one-way valve on the exhaust pipe. As a pressure buffer, the pressure stabilizing chamber can filter out the pressure fluctuations generated by the engine during the exhaust process, reduce airflow disturbances, reduce the impact of pressure fluctuations on fuel injection, and improve overall performance.

[0019] Optionally, the air-assisted fuel injection device also includes a fuel nozzle and a mixed gas nozzle, the fuel nozzle is arranged between the fuel inlet and the premixing chamber, and the mixed gas nozzle is arranged between the premixing chamber and the injection outlet, and the fuel nozzle and the mixed gas nozzle are both electrically connected to the control module through wiring terminals. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] Figure 1 It is a structural schematic diagram of a dual-fluid atomizing injection system without an independent gas source supply device in an embodiment of the present invention;

[0021] Figure 2 Schematic diagram of the structure of the air-assisted fuel injection device in an embodiment of the present invention. DETAILED DESCRIPTION

[0022] The following is further described in detail through specific implementation methods:

[0023] The symbols in the drawings of the specification include: air-assisted fuel injection device 1, cylinder 2, intake valve 3, intake duct 4, cylinder liner 5, crankshaft 6, connecting rod 7, piston 8, cylinder body 9, exhaust valve 10, exhaust duct 11, exhaust pressure sensor 12, back pressure valve 13, EGR valve 14, injection pressure sensor 15, pressure stabilizing chamber 16, one-way valve 17, fuel inlet 18, fuel nozzle terminal 19, fuel nozzle 20, air flow inlet 21, premixing chamber 22, mixed gas nozzle terminal 23, mixed gas nozzle 24, injection outlet 25.

[0024] Example

[0025] This embodiment is basically Figure 1 , Figure 2 As shown: a dual-fluid atomizing injection system without an independent air source supply device, including a control module, an exhaust gas circulation system and an air-assisted fuel injection device 1:

[0026] The engine in this example is a heavy oil piston 8 type engine, which includes a cylinder 2 head, an intake valve 3, an intake duct 4, a cylinder liner 5, a crankshaft 6, a connecting rod 7, a piston 8, a cylinder block 9 and an exhaust valve 10.

[0027] The exhaust gas circulation system includes an exhaust passage 11, an exhaust pressure sensor 12, a jet pressure sensor 15, and an EGR valve 14. One end of the exhaust passage 11 is used to connect to the exhaust system on the exhaust valve 10 side of the engine. The exhaust pressure sensor 12, the jet pressure sensor 15, and the EGR valve 14 are all installed on the exhaust passage 11, wherein the exhaust pressure sensor 12 is located on the intake side of the EGR valve 14, and the jet pressure sensor 15 is located on the exhaust side of the EGR valve 14; a pressure relief pipe is also provided on the exhaust pipe, one end of the pressure relief pipe is connected to the exhaust pipe, and the connection point is located between the exhaust pressure sensor 12 and the EGR valve 14, and a back pressure valve 13 is installed on the other end of the pressure relief pipe. A one-way valve 17 is provided on one end of the exhaust pipe close to the air-assisted fuel injection device 1. A pressure stabilizing chamber 16 is provided between the jet pressure sensor 15 and the one-way valve 17 on the exhaust pipe.

[0028] The air-assisted fuel injection device 1 comprises a fuel inlet 18, an injection outlet 25, a premixing chamber 22, a fuel nozzle 20 and a mixed gas nozzle 24. The fuel inlet 18 and the injection outlet 25 are respectively located at both ends of the premixing chamber 22 and are both connected to the premixing chamber 22. The fuel nozzle 20 is arranged between the fuel inlet 18 and the premixing chamber 22, and the mixed gas nozzle 24 is arranged between the premixing chamber 22 and the injection outlet 25. One end of the exhaust passage 11 away from the exhaust valve 10 is connected to the premixing chamber 22 through the airflow inlet 21 on the premixing chamber 22.

[0029] The control module, which is the engine ECU in this embodiment, the exhaust pressure sensor 12, the jet pressure sensor 15, the air-assisted fuel injection device 1, the fuel nozzle 20 (including the fuel nozzle terminal 19) and the mixed gas nozzle 24 (including the mixed gas nozzle terminal 23) are all electrically connected to the control module through the terminal.

[0030] After the fuel in the engine is burned, the piston 8 moves upward after the engine has finished working, and the exhaust valve 10 opens to discharge the compressed exhaust gas from the exhaust passage 11. The exhausted exhaust gas is guided to the air-assisted fuel injection device 1 through the EGR valve 14 to act on the direct injection process of the fuel in the cylinder. The EGR valve 14 can achieve different openings to control the pressure of the exhaust gas entering the air-assisted fuel injection device 1. The opening size depends on the pressure value detected by the injection pressure sensor 15. The monitored pressure value will be fed back to the control module, and the control module will control the opening size of the EGR valve 14 according to the pressure value, thereby determining the amount of exhaust gas flowing into the air-assisted fuel injection device 1.

[0031] The injection process is as follows: the fuel enters the air-assisted fuel injection device 1 from the fuel inlet. After the ECU sends an electrical signal to the air-assisted fuel injection device 1 through the wiring port, the solenoid valve of the air-assisted fuel injection device 1 opens to spray fuel into the premixing chamber 22. At this time, the premixing chamber 22 is already filled with exhaust gas of a certain pressure and temperature entering from the air inlet. When it is sprayed into the premixing chamber 22, it will interact with the compressed gas therein to achieve the first crushing of the fuel. Subsequently, after the mixture nozzle is energized through the wiring port, the oil-gas mixture after the initial crushing and atomization is sprayed from the outlet into the cylinder under the action of air pressure to achieve the secondary crushing and atomization of the fuel.

[0032] This embodiment combines the air-assisted fuel injection technology based on the dual-fluid atomization mechanism with the EGR technology, and solves the heavy oil atomization problem of the aviation piston 8 engine by introducing exhaust gas. At the same time, it eliminates the redundant equipment structure such as the air compressor or gas cylinder required for preparing compressed gas in the existing technical solution, and does not need to use an independent gas source, which greatly improves the reliability and lightness of the aviation piston 8 engine. At the same time, it creates favorable conditions for the application and promotion of air-assisted injection in commercial vehicles.

[0033] The above are only embodiments of the present invention. The invention is not limited to the fields involved in this implementation case. The common sense such as the known specific structures and characteristics in the scheme is not described in detail here. The ordinary technicians in the relevant field know all the common technical knowledge in the technical field to which the invention belongs before the application date or the priority date, can obtain all the existing technologies in the field, and have the ability to apply the conventional experimental means before that date. The ordinary technicians in the relevant field can improve and implement this scheme in combination with their own abilities under the enlightenment given by this application. Some typical known structures or known methods should not become obstacles for ordinary technicians in the relevant field to implement this application. It should be pointed out that for those skilled in the art, without departing from the structure of the present invention, several deformations and improvements can be made, which should also be regarded as the protection scope of the present invention, which will not affect the effect of the implementation of the present invention and the practicality of the patent. The protection scope required by this application shall be based on the content of its claims, and the specific implementation methods and other records in the specification can be used to explain the content of the claims.

Claims

1. A dual-fluid atomizing spray system without an independent gas supply device, characterized in that: Includes control module, exhaust gas recirculation system and air-assisted fuel injection: An exhaust gas circulation system, including an exhaust passage, an exhaust pressure sensor, an injection pressure sensor, and an EGR valve, wherein one end of the exhaust passage is used to be connected to the exhaust system on the exhaust valve side of the engine, and the exhaust pressure sensor, the injection pressure sensor, and the EGR valve are all installed on the exhaust passage, wherein the exhaust pressure sensor is located on the intake side of the EGR valve, and the injection pressure sensor is located on the exhaust side of the EGR valve; The air-assisted fuel injection device comprises a fuel inlet, an injection outlet and a premixing chamber, wherein the fuel inlet and the injection outlet are connected to the premixing chamber, and an end of the exhaust passage away from the exhaust valve is connected to the premixing chamber; The control module is electrically connected to the exhaust pressure sensor, the jet pressure sensor and the air-assisted fuel injection device.

2. The dual-fluid atomizing spray system without independent air source supply device according to claim 1, characterized in that: The exhaust pipe is also provided with a pressure relief pipe, one end of which is connected to the exhaust pipe, and the connection point is located between the exhaust pressure sensor and the EGR valve, and the other end of the pressure relief pipe is installed with a back pressure valve.

3. The dual-fluid atomizing spray system without independent gas source supply device according to claim 2, characterized in that: A one-way valve is arranged on one end of the exhaust pipe close to the air-assisted fuel injection device.

4. The dual-fluid atomizing spray system without independent gas source supply device according to claim 3, characterized in that: A pressure stabilizing chamber is provided between the jet pressure sensor and the one-way valve on the exhaust pipe.

5. The dual-fluid atomizing spray system without independent air source supply device according to claim 4, characterized in that: The air-assisted fuel injection device also includes a fuel nozzle and a mixed gas nozzle. The fuel nozzle is arranged between the fuel inlet and the premixing chamber, and the mixed gas nozzle is arranged between the premixing chamber and the injection outlet. The fuel nozzle and the mixed gas nozzle are both electrically connected to the control module through wiring terminals.

Images