A two-stroke heavy fuel piston engine of the spark ignited type
By using an auxiliary air pump and an auxiliary fuel supply system in an spark-ignition two-stroke heavy oil piston engine, the problems of poor atomization and combustion performance of heavy oil piston engines have been solved, achieving fine atomization and efficient combustion of heavy oil, improving the power-to-weight ratio and reducing fuel consumption.
Patent Information
- Application Number
- CN201911135319.4
- Authority / Receiving Office
- CN · China
- Patent Type
- Patents(China)
- Current Assignee / Owner
- Priority Date
- 2019-09-30
- Filing Date
- 2019-11-19
- Publication Date
- 2026-05-15
- Estimated Expiration
- 2039-11-19
AI Technical Summary
Existing low-power heavy oil piston engines for aviation suffer from poor atomization and combustion performance, resulting in problems such as low power-to-weight ratio, complex structure, increased airframe weight, and increased fuel consumption.
It adopts an spark-ignition two-stroke heavy oil piston engine. Through an auxiliary gas pump and a gas-assisted fuel supply system, the eccentric wheel drives the pump piston to work, precisely controlling the gas supply. The oil-gas mixture is injected into the combustion chamber at supersonic speed through the auxiliary gas metering injection valve, achieving fine atomization of heavy oil.
It improves the combustion performance of heavy oil, increases the power-to-weight ratio, reduces engine weight and fuel consumption, and simplifies the structure.
Smart Images
Figure CN110848066B_ABST
Abstract
Description
Technical Field
[0001] This invention belongs to the field of engine technology, and specifically relates to an spark-ignition two-stroke heavy oil piston engine. Background Technology
[0002] Heavy oil is highly viscous, has a high flash point, and is difficult to volatilize, making it safer and more reliable during transportation and storage. As a result, it is highly favored in the military, shipbuilding, and aero-engine fields, especially in the field of small unmanned aerial vehicle (UAV) engines, where it has great development potential. The United States has listed heavy oil engines as one of the important development goals of UAV technology in its "Unmanned Aerial Vehicle (UAV) Roadmap (2005-2030)". In order to enhance national defense capabilities, my country is also actively promoting the research and development of heavy oil engines.
[0003] Currently, most low-power heavy oil piston engines for aviation are two-stroke engines. The reason for using a two-stroke design is to meet the high power-to-weight ratio requirements of aviation engines. Two-stroke engines themselves have a simple structure, fewer moving parts, high power density per unit volume, and relatively low weight, which meets the requirements of lightweight and high power-to-weight ratio for UAV power systems. However, due to the high viscosity of heavy oil, its atomization and combustion performance are poor. Traditional compression ignition or spark ignition methods are insufficient to achieve the combustion requirements of heavy oil engines. Therefore, methods such as fine atomization, auxiliary preheating of heavy oil, and improved combustion chamber structure are typically used to meet the combustion requirements of heavy oil engines. However, excessive addition of auxiliary preheating equipment leads to structural complexity, increased airframe weight, decreased power-to-weight ratio, increased fuel consumption, and shorter flight range. Summary of the Invention
[0004] The purpose of this invention is to provide a spark-ignition two-stroke heavy oil piston engine, thereby overcoming the shortcomings of traditional heavy oil engines such as poor atomization and combustion performance and low power-to-weight ratio.
[0005] To achieve the above objectives, the present invention provides a spark-ignition two-stroke heavy oil piston engine, comprising: an engine body including a crankcase, a crankshaft disposed within the crankcase, and an extended end shaft disposed on one side of the crankshaft; an auxiliary air pump including a pump cylinder head and a pump cylinder body, a pump cylinder bore disposed within the pump cylinder body, a pump piston disposed within the pump cylinder bore, a gas compression chamber formed between the piston top of the pump piston and the pump cylinder head and the pump cylinder bore, an outlet port communicating with the gas compression chamber being provided on the pump cylinder head, a one-way gas valve being provided between the outlet port and the gas compression chamber, and a pressure relief valve assembly communicating with the gas compression chamber; the extended end shaft being rotatably connected to one end of a pump connecting rod via an eccentric wheel, the extended end shaft being rotatably connected to one end of a pump connecting rod via an eccentric wheel. The other end is connected to the piston of the air pump via a piston pin; and an air-assisted fuel supply system, which includes an overflow pressure regulating valve, the oil inlet side pipeline of the overflow pressure regulating valve being connected in series with the heavy oil tank and the oil pump to form an oil inlet circuit, the air inlet of the overflow pressure regulating valve being connected to the air outlet of the auxiliary air pump, the oil outlet pipeline of the overflow pressure regulating valve being connected to the inlet of the heavy oil metering injection valve, the outlet of the heavy oil metering injection valve being connected to one inlet of the oil-air mixing rail, the other inlet of the oil-air mixing rail being connected to the air outlet pipeline of the overflow pressure regulating valve, the outlet of the oil-air mixing rail being connected to the inlet of the auxiliary air metering injection valve, the auxiliary air metering injection valve having a Laval injection port, the Laval injection port being located at the top of the combustion chamber of the engine body.
[0006] Preferably, in the above technical solution, an air pump cylinder sleeve is embedded in the air pump cylinder body, and the air pump cylinder bore is located inside the air pump cylinder sleeve along the axis of the air pump cylinder sleeve; a recessed stop is provided at one end of the air pump cylinder sleeve facing the air pump cylinder head, the recessed stop coincides with the axis of the air pump cylinder bore, and its diameter is larger than the diameter of the air pump cylinder bore; an annular oil reservoir is provided on the stepped surface between the recessed stop and the air pump cylinder bore, and the outline of the oil reservoir corresponds to the outline of the air pump cylinder bore; a gas inlet hole is provided on the air pump cylinder sleeve, and the gas inlet hole connects the air pump cylinder bore to the outside of the air pump cylinder sleeve.
[0007] Preferably, in the above technical solution, the air pump cylinder body is further provided with a crankshaft chamber, the crankshaft chamber is connected to the end of the air pump cylinder bore facing away from the air pump cylinder head; two air pump main shaft holes are provided opposite to each other on the side of the air pump cylinder body, the air pump main shaft holes are connected to the crankshaft chamber; the side of the air pump cylinder body is also provided with an air inlet hole connected to the crankshaft chamber.
[0008] Preferably, in the above technical solution, the gas inlet hole is interconnected with the crankshaft chamber.
[0009] Preferably, in the above technical solution, the one-way valve includes a valve plate that is slidably disposed in the recessed stop, the diameter of the valve plate being adapted to the diameter of the recessed stop; a first spring is provided between the valve plate and the top of the gas compression chamber.
[0010] Preferably, in the above technical solution, the eccentric wheel is sleeved on one end of the air pump connecting rod through a first bearing, and the extended end shaft is disposed in the main shaft hole of the air pump through a second bearing, and passes through the eccentric hole of the eccentric wheel and is fixed to the eccentric wheel.
[0011] Preferably, in the above technical solution, the pressure relief valve assembly includes: an upper pressure relief pipe disposed in the air pump cylinder head, one end of which is connected to the gas compression chamber; a pressure relief valve chamber disposed in the cylinder wall of the air pump cylinder body, the bottom of which is connected to one end of a lower pressure relief pipe, the opening of which is located on the mounting surface between the air pump cylinder body and the air pump cylinder head, and corresponds to the other end of the upper pressure relief pipe; the lower pressure relief pipe is disposed in the cylinder wall of the air pump cylinder body, and its other end is connected to the crankshaft chamber; a pressure relief valve seat disposed at the opening of the pressure relief valve chamber, a pressure relief hole is formed through the center of the pressure relief valve seat, and a conical hole is formed below the pressure relief hole; and a valve stem sleeved in the pressure relief valve chamber, one end of which faces the pressure relief valve seat and is provided with a steel ball, and a second spring is provided between the other end of the valve stem and the bottom of the pressure relief valve chamber.
[0012] Preferably, in the above technical solution, the engine body is a single-cylinder or multi-cylinder structure.
[0013] Compared with existing technologies, the present invention has the following advantages:
[0014] 1. The auxiliary air pump in this invention uses the engine crankshaft to directly drive the pump piston through an eccentric wheel, which makes the phase relationship between the crankshaft and the eccentric wheel more precise, improves the driving efficiency of the air pump, simplifies the structure, reduces the weight of the engine, and improves the power-to-weight ratio.
[0015] 2. The gas-assisted fuel supply system of the present invention combines auxiliary gas with heavy oil, and injects the gas-oil mixture at supersonic speed through the Laval injection port in the auxiliary gas metering injection valve, so that the heavy oil is finely atomized and forms tiny particles in the combustion chamber for combustion, thereby improving the combustion performance of heavy oil. Attached Figure Description
[0016] Figure 1 This is a structural diagram of a first embodiment of the spark-ignition two-stroke heavy oil piston engine of the present invention.
[0017] Figure 2This is a cross-sectional view of a first embodiment of the spark-ignition two-stroke heavy oil piston engine of the present invention.
[0018] Figure 3 This is a cross-sectional view of a second embodiment of the spark-ignition two-stroke heavy oil piston engine of the present invention.
[0019] Figure 4 This is a cross-sectional view of the auxiliary air pump of the spark-ignition two-stroke heavy oil piston engine of the present invention.
[0020] Figure 5 yes Figure 4 Local magnification in Figure I .
[0021] Figure 6 This is a structural diagram of the cylinder liner of the auxiliary air pump.
[0022] Figure 7 This is a connection diagram of the gas-assisted fuel supply system in this invention.
[0023] Explanation of key figure labels:
[0024] 1-Engine block, 2-Auxiliary air pump, 3-Air-assisted fuel supply system, 4-Spark plug, 11-Cylinder block, 12-Cylinder head, 13-Crankcase, 14-Crankshaft, 15-Piston connecting rod assembly, 17-Combustion chamber, 18-Tachometer, 20-Crankshaft chamber, 21-Gas compression chamber, 22-Air pump cylinder liner, 23-Air pump piston, 24-Eccentric wheel, 25-Valve plate, 26-Depression relief valve assembly, 27-Air pump cylinder bore, 28-Recessed stop, 29-Oil reservoir, 210-Gas inlet hole, 211-Air pump cylinder head, 212-Air pump cylinder block, 213-Air pump spindle bore, 214-Inlet port, 215-Outlet port, 216-First spring, 217-Upper pressure relief pipe, 218 - Pressure relief valve chamber, 219- Lower pressure relief pipe, 220- Pressure relief valve seat, 221- Pressure relief hole, 222- Valve stem, 223- Steel ball, 224- Second spring, 225- First bearing, 226- Eccentric hole, 227- Second bearing, 228- Convex ring, 229- Curved boss, 230- Air pump connecting rod, 31- Overflow pressure regulating valve, 32- Heavy oil tank, 33- Oil pump, 34- Extended end shaft, 35- Heavy oil metering injection valve, 36- Oil-air mixing rail, 37- Auxiliary air metering injection valve, 38- Oil inlet pipe, 39- Oil return pipe, 310- Air outlet pipe, 311- Oil outlet pipe, 161- Intake manifold, 162- Throttle valve, 163- Exhaust pipe, 164- Lubricating oil pipe. Detailed Implementation
[0025] The specific embodiments of the present invention will now be described in detail with reference to the accompanying drawings, but it should be understood that the scope of protection of the present invention is not limited to the specific embodiments.
[0026] Example 1
[0027] like Figure 1 , Figure 2 , Figure 4 and Figure 7 As shown, this embodiment is an spark-ignition two-stroke, two-cylinder, opposed heavy oil piston engine, comprising: engine body 1, auxiliary air pump 2, air-assisted fuel supply system 3, spark plug 4, cylinder block 11, cylinder head 12, crankcase 13, crankshaft 14, piston connecting rod assembly 15, combustion chamber 17, speed encoder 18, overflow pressure regulating valve 31, heavy oil tank 32, oil pump 33, extended end shaft 34, heavy oil metering injection valve 35, oil-air mixing rail 36, auxiliary air metering injection valve 37, oil inlet pipe 38, oil return pipe 39, exhaust pipe 310, oil outlet pipe 311, intake manifold 161, throttle valve 162, exhaust pipe 163, and lubricating oil pipeline 164. The engine body 1 includes a crankcase 13, in which a crankshaft 14 is installed. One end of an extended shaft 34 is connected to the output end of the crankshaft 14, and the other end of the extended shaft 34 is connected to an output spline shaft. Two cylinder blocks 11 of the engine are horizontally positioned on both sides of the crankcase 13, and the two cylinder blocks 11 are staggered along the axis of the crankshaft 14. A cylinder head 12 is installed at the cylinder port of each of the two cylinder blocks 11. A set of piston connecting rod assembly 15 is installed in each piston cylinder of each cylinder block 11. The movable end of the connecting rod in the piston connecting rod assembly 15 is installed on the crankshaft 14. A combustion chamber 17 is carved out in each cylinder head 12 at a position opposite to the cylinder port of the cylinder block 11. Two pairs of spark plugs 4 are installed on the cylinder head 12, and the ignition points of each pair of spark plugs 4 are close to each other, and their tails are symmetrically installed at a certain angle on the top of the combustion chamber 17. A speed encoder 18 is fixedly installed on the output end of the crankshaft 14.
[0028] The engine body 1 also includes an intake and exhaust system, a lubricating oil supply system, and an electronic control system. The intake and exhaust system includes an intake manifold 161 connected to the crankcase 13, an exhaust pipe 163 connected to the cylinder block 11, and a throttle valve 162 installed inside the intake manifold 161. The lubricating oil supply system includes a lubricating oil nozzle installed on the crankcase, which is connected to a lubricating oil tank and a lubricating oil metering pump located outside the engine body 1 via a lubricating oil pipe 164. The electronic control system includes an engine electronic control unit, which is connected to a cylinder temperature sensor, a speed sensor, an intake air temperature and pressure sensor, a throttle position sensor, an atmospheric pressure sensor, an ignition coil sensor, a fuel level sensor, and a lubricating oil level sensor via wiring harnesses.
[0029] The auxiliary air pump 2 is mounted on the crankcase 13 and located at the extended end shaft 34. The overflow pressure regulating valve 31 is mounted on the auxiliary air pump 2 and connected to it. The heavy oil metering injection valve 35, the oil-air mixing rail 36 and the auxiliary air metering injection valve 37 are all mounted on the top of the cylinder head 12.
[0030] Continue to refer to Figure 1 , Figure 4 and Figure 7 In the gas-assisted fuel supply system 3, the overflow pressure regulating valve 31 has two ports on its inlet side: an inlet port and a return port. These two ports are connected in series with the heavy oil tank 32 and the oil pump 33 through the inlet pipe 38 and the return pipe 39, respectively, to form an inlet circuit. The overflow pressure regulating valve 31 is directly installed on the auxiliary gas pump 2, and the outlet port 215 of the auxiliary gas pump 2 is directly connected to the inlet port of the overflow pressure regulating valve 31. The inlet of the heavy oil metering injection valve 35 is connected to the outlet port of the overflow pressure regulating valve 31 through the outlet pipe 311, and the outlet of the heavy oil metering injection valve 35 is connected to one inlet of the gas-fuel mixing rail 36. The outlet port of the overflow pressure regulating valve 31 is connected to the other inlet of the gas-fuel mixing rail 36 through the outlet pipe 310. The outlet of the gas-fuel mixing rail 36 is connected to the inlet of the auxiliary gas metering injection valve 37. The nozzle of the auxiliary gas metering injection valve 37 is a Laval nozzle, and this Laval nozzle is located at the top of the combustion chamber 17.
[0031] Continue to refer to Figure 4 , Figure 5 and Figure 6The auxiliary air pump 2 in this embodiment includes: a crankshaft chamber 20, a gas compression chamber 21, an air pump cylinder liner 22, an air pump piston 23, an eccentric wheel 24, a valve plate 25, a pressure relief valve assembly 26, an air pump cylinder bore 27, a concave stop 28, an oil reservoir 29, a gas inlet hole 210, an air pump cylinder head 211, an air pump cylinder body 212, an air pump main shaft bore 213, an air inlet hole 214, an air outlet hole 215, a first spring 216, an upper pressure relief pipe 217, a pressure relief valve chamber 218, a lower pressure relief pipe 219, a pressure relief valve seat 220, a pressure relief hole 221, a valve stem 222, a steel ball 223, a second spring 224, a first bearing 225, an eccentric hole 226, a second bearing 227, a convex ring 228, a curved boss 229, and an air pump connecting rod 230. The air pump cylinder head 211 is connected to the air pump cylinder body 212 by bolts. The air pump cylinder body 212 has a cylinder liner mounting hole inside, and the hole is located on the mounting surface between the air pump cylinder head 211 and the air pump cylinder body 212. The crankshaft chamber 20 is located inside the air pump cylinder body 212 and is connected to the side hole of the cylinder liner mounting hole facing away from the mounting surface of the air pump cylinder body 212. The side wall of the air pump cylinder body 212 has two mutually aligned air pump spindle holes 213, both of which are connected to the crankshaft chamber 20. The side wall of the air pump cylinder body 212 also has multiple air intake holes 214 that are connected to the crankshaft chamber 20. On the outer wall of one end of the air pump cylinder liner 22, four curved bosses 229 are evenly arranged circumferentially around the axis of the air pump cylinder liner 22. On the outer wall of the other side of the air pump cylinder liner 22, a raised ring 228 is provided. On the air pump cylinder liner 22, between the raised ring 228 and the curved bosses 229, 3 to 12 gas inlet holes 210 are arranged circumferentially, communicating with the inner hole of the air pump cylinder liner 22. The inner hole of the air pump cylinder liner 22 is the air pump cylinder bore 27. The air pump cylinder liner 22 is embedded into the air pump cylinder body 212 by tightly fitting it into the cylinder liner mounting hole. Since the curved bosses 229 and the raised ring 228 have a certain thickness, an overhead area is formed between the outer wall of the air pump cylinder liner 22 and the cylinder liner mounting hole. This overhead area communicates with the crankshaft chamber 20, and the gas inlet holes 210 connect the air pump cylinder bore 27 to the overhead area. A recessed stop 28 is provided at one end of the air pump cylinder liner 22 facing the air pump cylinder head 211. The recessed stop 28 coincides with the axis of the air pump cylinder bore 27, and its diameter is larger than that of the air pump cylinder bore 27. A stepped surface is formed between the recessed stop 28 and the air pump cylinder bore 27. An annular oil reservoir 29 is carved on the stepped surface. The outline of the oil reservoir 29 corresponds to the outline of the air pump cylinder bore 27. The width and height of the oil reservoir 29 are 0.3~3mm. The air pump piston 23 is installed in the air pump cylinder bore 27, with its piston top facing the air pump cylinder head 211. The area formed between the piston top of the air pump piston 23, the air pump cylinder head 211, and the air pump cylinder bore 27 is a gas compression chamber 21. An outlet hole 215 communicating with the gas compression chamber 21 is opened on the air pump cylinder head 211.A valve plate 25 is installed inside the recessed stop 28. The diameter of the valve plate 25 is such that it forms a clearance fit with the recessed stop 28 with a small tolerance value, so that the valve plate 25 can slide up and down inside the recessed stop 28. The thickness of the valve plate 25 is no more than 1.5mm. A first spring 216 is installed between the valve plate 62 and the top of the cylinder compression chamber 21. The valve plate 25 and the first spring 216 together form a one-way valve.
[0032] The extended end shaft 34 passes through the crankshaft chamber 20 and is installed in the two air pump main shaft holes 213 through the second bearing 227; a section of the extended end shaft 34 located in the crankshaft chamber 20 passes through the eccentric hole 226 and is fixed to the eccentric wheel 24 by means of a key or interference fit. The eccentric wheel 24 is installed in the first bearing 225, which is installed at one end of the air pump connecting rod 230. The other end of the air pump connecting rod 230 is connected to the air pump piston 23 through a piston pin.
[0033] Continue to refer to 4 and Figure 5 The pressure relief valve assembly 26 includes an upper pressure relief pipe 217, which is located in the air pump cylinder head 211. One end of the upper pressure relief pipe 217 passes through the air pump cylinder head 211 and is connected to the top of the gas compression chamber 21. The other end of the upper pressure relief pipe 217 is located on the mounting surface of the air pump cylinder head 211. The pressure relief valve chamber 218 is located in the side wall of the air pump cylinder body 212, and its opening is located on the mounting surface of the air pump cylinder body 212. The opening of the pressure relief valve chamber 218 is aligned with the opening of the upper pressure relief pipe 217. The bottom of the pressure relief valve chamber 218 is connected to one end of the lower pressure relief pipe 219, which is also located in the side wall of the air pump cylinder body 212. The other end of the lower pressure relief pipe is located on the wall of the cylinder liner mounting hole, so that the lower pressure relief pipe is connected to the overhead area between the outer wall of the air pump cylinder liner 22 and the cylinder liner mounting hole. A pressure relief valve seat 220 is embedded in the opening of the pressure relief valve chamber 218. A pressure relief hole 221 is opened through the center of the pressure relief valve seat 220. The lower part of the pressure relief hole 221 is a conical hole. The top surface of the pressure relief valve seat 220 is flush with the top surface of the lower housing 212. A valve stem 222 is installed in the pressure relief valve chamber 218. A steel ball 223 is provided at one end of the valve stem 222 facing the pressure relief valve seat 220. A second spring 224 is installed between the other end of the valve stem 222 and the bottom of the pressure relief valve chamber 218. The tension of the second spring 224 can press the steel ball 223 tightly into the conical hole at the bottom of the pressure relief valve seat 220.
[0034] Example 2
[0035] like Figure 3As shown, this embodiment is a spark-ignition two-stroke single-cylinder heavy oil piston engine. The difference between this single-cylinder engine and the spark-ignition two-stroke twin-cylinder opposed heavy oil piston engine in Embodiment 1 lies only in the engine body 1. The engine body 1 in this embodiment includes a crankcase 13, in which a crankshaft 14 is installed. A cylinder block 11 is located on one side of the crankcase 13, and a cylinder head 12 is installed at the cylinder port of the cylinder block 11. A piston-connecting rod assembly 15 is installed inside the cylinder block 11, and the connecting rod in the piston-connecting rod assembly 15 is mounted on the crankshaft 14. A combustion chamber 17 is located in the cylinder head 12 at a position opposite to the cylinder port of the cylinder block 11. An extended end shaft 34 is connected to the output end of the crankshaft 14, and a speed encoder 18 is also fixedly installed on the output end of the crankshaft 14. A pair of spark plugs 4 are installed on the cylinder head 12, and the ignition points of the two spark plugs 4 are close to each other, with their tails forming a certain angle and symmetrically installed on the top of the combustion chamber 17.
[0036] In this embodiment, the types and installation methods of the auxiliary air pump 2, the air-assisted fuel supply system 3, the lubricating oil supply system, and the engine electronic control system are the same as those of the spark-ignition two-stroke twin-cylinder opposed heavy oil piston engine in Embodiment 1, and will not be repeated here.
[0037] The working principle of the spark-ignition two-stroke heavy oil piston engine of this invention will be further explained below to enable those skilled in the art to more clearly understand the technical solution:
[0038] 1. When the heavy oil piston engine is working, the crankshaft 14 directly drives the air pump connecting rod 230 through the eccentric wheel 24 to drive the air pump piston 23. By changing the installation angle of the eccentric wheel 24, the phase difference between the eccentric wheel 24 and the crankshaft 14 can be directly obtained, thereby more accurately controlling the movement sequence of the air pump piston 23 and the timing of the auxiliary gas supply. The one-way valve of the air pump limits the air pressure value and opening time when the valve plate 25 opens by adjusting the elastic force of the first spring 216, thereby accurately limiting the gas supply pressure and supply amount of the auxiliary gas pump 2. When the valve plate 25 moves up and down, the lubricating oil inside the oil reservoir 29 will adhere to the gaps around it, thereby increasing the viscosity of the gas and preventing the auxiliary gas from being sucked back when the air pump piston 23 moves downward, thus ensuring the stability of the auxiliary gas supply.
[0039] 2. The auxiliary air pump 2 is also equipped with a pressure relief valve assembly 26. When the air pump piston 23 compresses the gas, if the pressure inside the gas compression chamber 21 is too high, the gas will overcome the elastic force of the second spring 224 and push the steel ball 223 open, so that the gas returns to the crankshaft chamber 20 and balances the excessive air pressure.
[0040] 3. The outlet 215 of the auxiliary air pump 2 is directly connected to the inlet of the overflow pressure regulating valve 31. The oil pump 33 draws heavy oil from the heavy oil tank 32 and delivers it to the inlet side of the overflow pressure regulating valve 31 through the inlet pipe 38. The heavy oil forms a certain pressure on the inlet side of the overflow pressure regulating valve 31. The overflow pressure regulating valve 31 can control the pressure on the inlet side and the air inlet side, and form a stable pressure difference between the two sides. Excess oil on the inlet side is returned to the heavy oil tank 32 through the return pipe 39. The heavy oil metering injection valve 35 can control the injection timing and injection quantity of heavy oil. The auxiliary air enters the oil... In the air-fuel mixing rail 36, since the nozzle of the auxiliary gas metering injection valve 37 is a Laval nozzle, its Laval physical structure allows the auxiliary gas to be injected into the combustion chamber 17 at five times the speed of sound. At this time, the auxiliary gas forms extremely high turbulent kinetic energy in the mixing rail 36. When the heavy oil metering injection valve 35 is opened, the heavy oil is injected into the mixing rail 36 and then carried by the turbulent kinetic energy of the auxiliary gas to the nozzle and injected into the combustion chamber 17. When the oil-fuel mixture is released from the nozzle, the heavy oil is atomized into particles smaller than 6 μm. Through fine atomization, the combustion performance of the heavy oil is improved, and it can burn rapidly to form an explosive airflow that drives the piston of the engine to do work.
[0041] In summary, the heavy oil engine of this invention directly drives the auxiliary air pump via an eccentric wheel, which not only improves the starting efficiency of the auxiliary air pump and makes the phase relationship between the crankshaft and the eccentric wheel more precise, but also simplifies the engine structure, improves the power-to-weight ratio, and reduces fuel consumption. Furthermore, this invention utilizes a gas-assisted fuel supply system to finely atomize heavy oil into small particles and inject them into the combustion chamber, thereby improving the combustion performance and utilization rate of heavy oil.
[0042] The foregoing description of specific exemplary embodiments of the invention is for illustrative and explanatory purposes. These descriptions are not intended to limit the invention to the precise forms disclosed, and it will be apparent that many changes and variations can be made in accordance with the foregoing teachings. The exemplary embodiments were chosen and described in order to explain the specific principles of the invention and its practical application, thereby enabling those skilled in the art to implement and utilize various different exemplary embodiments of the invention, as well as various different choices and variations. The scope of the invention is intended to be defined by the claims and their equivalents.
Claims
1. A spark-ignition two-stroke heavy oil piston engine, characterized in that, include: The engine body (1) includes a crankcase (13) with a crankshaft (14) inside the crankcase (13) and an extended end shaft (34) on one side of the crankshaft (14). An auxiliary air pump (2) includes an air pump cylinder head (211) and an air pump cylinder body (212). The air pump cylinder body (212) has an air pump cylinder bore (27). An air pump piston (23) is located within the air pump cylinder bore (27). The piston top of the air pump piston (23) forms a gas compression chamber (21) between the air pump cylinder head (211) and the air pump cylinder bore (27). The air pump cylinder head (211) has an outlet hole (215) communicating with the gas compression chamber (21). A gas check valve is provided between the outlet hole (215) and the gas compression chamber. A pressure relief valve assembly (26) is connected to the gas compression chamber. The extended end shaft (34) is rotatably connected to one end of the air pump connecting rod (230) via an eccentric wheel (24). The other end of the air pump connecting rod (230) is connected to the air pump piston (23) via a piston pin. The gas-assisted fuel supply system (3) includes an overflow pressure regulating valve (31). The oil inlet pipe of the overflow pressure regulating valve (31) is connected in series with the heavy oil tank (32) and the oil pump (33) to form an oil inlet circuit. The air inlet of the overflow pressure regulating valve (31) is connected to the air outlet (215) of the auxiliary gas pump (2). The oil outlet pipe of the overflow pressure regulating valve (31) is connected to the inlet of the heavy oil metering injection valve (35). The outlet of the heavy oil metering injection valve (35) is connected to one inlet of the oil-gas mixing rail (36). The other inlet of the oil-gas mixing rail (36) is connected to the air outlet pipe of the overflow pressure regulating valve. The outlet of the oil-gas mixing rail (36) is connected to the inlet of the auxiliary gas metering injection valve (37). The auxiliary gas metering injection valve (37) has a Laval injection port, which is located at the top of the combustion chamber (17) of the engine body (1).
2. The spark-ignition two-stroke heavy oil piston engine according to claim 1, characterized in that, The air pump cylinder body (212) is fitted with an air pump cylinder sleeve (22), and the air pump cylinder bore (27) is located inside the air pump cylinder sleeve (22) along the axis of the air pump cylinder sleeve (22). A recessed stop (28) is provided at one end of the air pump cylinder sleeve (22) facing the air pump cylinder head (211). The recessed stop (28) coincides with the axis of the air pump cylinder bore (27), and its diameter is larger than the diameter of the air pump cylinder bore (27). An annular oil reservoir (29) is provided on the stepped surface between the recessed stop (28) and the air pump cylinder bore (27). The outline of the oil reservoir (29) corresponds to the outline of the air pump cylinder bore (27). A gas inlet hole (210) is provided on the air pump cylinder sleeve (22), and the gas inlet hole (210) connects the air pump cylinder bore (27) with the outside of the air pump cylinder sleeve (22).
3. The spark-ignition two-stroke heavy oil piston engine according to claim 2, characterized in that, The air pump cylinder body (212) is also provided with a crankshaft chamber (20), which is connected to the end of the air pump cylinder bore (27) facing away from the air pump cylinder cover (211); the side of the air pump cylinder body (212) is provided with two air pump main shaft holes (213), which are connected to the crankshaft chamber (20); the side of the air pump cylinder body (212) is also provided with an air inlet (214) connected to the crankshaft chamber (20).
4. The spark-ignition two-stroke heavy oil piston engine according to claim 3, characterized in that, The gas inlet (210) is connected to the crankshaft chamber (20).
5. The spark-ignition two-stroke heavy oil piston engine according to claim 2, characterized in that, The one-way valve includes a valve plate (25) that is slidably disposed in the recess (28), the diameter of the valve plate (25) being adapted to the diameter of the recess (28); a first spring (216) is provided between the valve plate (25) and the top of the gas compression chamber (21).
6. The spark-ignition two-stroke heavy oil piston engine according to claim 3, characterized in that, The eccentric wheel (24) is sleeved on one end of the air pump connecting rod (230) through the first bearing (225), and the extended end shaft (34) is provided in the air pump main shaft hole (213) through the second bearing (227), and passes through the eccentric hole (226) of the eccentric wheel (24) and is fixed to the eccentric wheel (24).
7. The spark-ignition two-stroke heavy oil piston engine according to claim 3, characterized in that, The pressure relief valve assembly (26) includes: An upper pressure relief pipe (217) is provided in the air pump cylinder head (211), and one end of the upper pressure relief pipe (217) is connected to the gas compression chamber (21); The pressure relief valve chamber (218) is located in the cylinder wall of the air pump cylinder body (212). The bottom of the pressure relief valve chamber (218) is connected to one end of the lower pressure relief pipe (219). The opening of the pressure relief valve chamber (218) is located on the mounting surface between the air pump cylinder body (212) and the air pump cylinder cover (211), and corresponds to the other end of the upper pressure relief pipe (217). The lower pressure relief pipe (219) is located in the cylinder wall of the air pump cylinder body (212), and its other end is connected to the crankshaft chamber (20). A pressure relief valve seat (220) is located at the opening of the pressure relief valve chamber (218), and a pressure relief hole (221) is formed through the center of the pressure relief valve seat (220). Below the pressure relief hole (221) is a conical hole. A valve stem (222) is fitted inside the pressure relief valve cavity (218). One end of the valve stem (222) faces the pressure relief valve seat (220) and is provided with a steel ball (223). A second spring (224) is provided between the other end of the valve stem (222) and the bottom of the pressure relief valve cavity (218).
8. The spark-ignition two-stroke heavy oil piston engine according to claim 1, characterized in that, The engine body (1) is a single-cylinder or multi-cylinder structure.