Active crankcase negative pressure breathing device for an engine

Abstract

The utility model discloses a kind of active crankcase negative pressure breathing devices of engine, including breather housing being installed on crankcase by crankcase cover plate, and oil-gas separation device is installed on the upper opening of the breather housing of sealing cover, shunt centrifugal filter device for removing impurities contained in oil by centrifugal force is installed in the inner chamber of breather housing, centrifugal filter device is driven to rotate by the oil pressure provided by engine, and the centrifugal filter device also synchronously drives fan device for extracting mixed oil gas in crankcase. The utility model is simple in structure, safe and reliable, and can actively extract and separate mixed gas in crankcase.

Description

Technical Field

[0001] This utility model relates to the technical field of engines, and in particular to an active crankcase negative pressure breathing device for engines. Background Technology

[0002] When an engine is running, the high-temperature, high-pressure gases produced by fuel combustion in the combustion chamber can seep down into the crankcase through the piston ring gaps, increasing the pressure inside the crankcase. In gas engines using natural gas or other combustible gases as fuel, these downflowing high-temperature, high-pressure gases contain some combustible gases. Prolonged downflow can increase the concentration of combustible gases in the crankcase, creating an explosion risk. This downflowing mixture contains unburned fuel vapor, high-temperature water vapor, acidic gases (SO2), combustion exhaust gases, and particulate matter (smoke), which can cause the following damage to the engine oil in the oil pan and engine performance: 1. Engine oil dilution: Unburned fuel and vapors dilute engine oil, reducing its viscosity and lubrication performance, leading to a decrease in oil film strength and exacerbating wear on machine parts.

[0003] 2. Accelerated oil oxidation: High-temperature exhaust gas and oxygen accelerate oil oxidation, generating gum and deposits that clog the oil passages.

[0004] 3. Acidic corrosion: SO2 in the exhaust gas combines with water vapor to form sulfuric acid, which corrodes metal parts such as cylinder walls and piston rings, leading to rust and wear.

[0005] 4. Formation of sludge and carbon deposits: Water vapor mixes with engine oil to form an emulsion, which combines with unburned carbon particles to form sludge, clogging the oil filter and oil passages.

[0006] 5. Decreased lubrication performance: High-temperature particles (such as carbon soot) in blow-by gas will grind the engine oil, destroy its lubrication, and aggravate the wear of components such as crankshaft and camshaft.

[0007] Traditional crankcase breathers only have a simple ventilation function. They directly discharge the oil-gas mixture in the crankcase to the atmosphere or return it to the oil pan after simple filtration through a condenser or cooling mesh. The following two structures are common: Figure 1The diagram shows a breather with a condenser structure. This type of breather mainly consists of three parts: a condenser 71, a breather body 72, and a drain port 73. The condenser 71 is composed of an inner tube, a middle tube, and an outer shell, which are fitted together sequentially. The air-fuel mixture in the crankcase enters the breather body 72 through the crankcase flange 74, then passes upwards through the condenser flange 75 and enters the inner tube of the condenser 71. After entering the inner tube, the air-fuel mixture needs to enter the middle tube space through the opening at the top and the top of the inner tube, and then flows out through the opening at the bottom of the middle tube into the outer shell space of the condenser 71. The air-fuel mixture in the crankcase needs to go through this up-and-down cycle multiple times before finally being discharged into the atmosphere through the exhaust flange 76 at the top. During this process, the temperature of the air-fuel mixture in the crankcase will drop significantly. Most of the oil mist and water vapor in the mixture will condense into liquid and flow from the small hole at the bottom of the inner tube to the bottom of the breather body 72 for accumulation. Due to the different densities of oil and water, some of the condensed oil can flow back to the oil pan through the crankcase connecting flange 74. The remaining dirty oil and wastewater can be discharged periodically by opening the ball valve of the drain port 73.

[0008] Figure 2 The diagram shows a respirator with a cooling plate structure. The respirator includes a longitudinally arranged first straight pipe 81, an inclined second straight pipe 82, and a horizontally arranged third straight pipe 83, wherein a cooling plate assembly 84 is disposed within the first straight pipe 81. Figure 3 As shown, the cooling plate assembly 84 consists of a support rod 841 and cooling plates 842 spaced apart and mounted on the support rod. The cooling plates 842 are metal plates with numerous holes, and the holes on adjacent cooling plates 842 are staggered to increase airflow resistance. After the crankcase mixture enters the third straight pipe 83 and the second straight pipe 82 sequentially, it is first blocked by multi-layered baffles 85 welded to the third straight pipe 83 and the second straight pipe 82. The baffles 85 are staggered vertically, with each baffle 85 only blocking most of the diameter of the straight pipe. The lower baffle 85 has a notch at its bottom to facilitate the return of condensed engine oil to the crankcase. After passing through the third straight pipe 83 and the second straight pipe 82, the air-fuel mixture enters the bottom of the first straight pipe 81, and then passes through the layers of cooling plates 842 before finally connecting with the atmosphere. During this process, the airflow velocity in the crankcase is greatly reduced, and most of the oil mist and water vapor in the air-fuel mixture will condense into liquid and fall to the bottom of the first straight pipe 81 for storage. Furthermore, due to the different densities of engine oil and water, some of the condensed engine oil can flow back to the oil pan through the third straight pipe 83, while the remaining dirty oil and wastewater can be discharged periodically by opening the ball valve of the drain port 86.

[0009] Both of the above respirators have the following defects: 1. Three major leakage problems: Due to the layers of obstruction by the condenser and cooling fins, the air-fuel mixture in the crankcase cannot be discharged in time, resulting in positive pressure in the crankcase. This causes the air-fuel mixture to overflow (air leakage) from the crankshaft oil seal, engine block window cover, cylinder head cover, inspection window cover, and oil pump base, and then leak oil after cooling. Even the coolant may leak out from weak points due to thermal expansion (water leakage).

[0010] 2. Environmental pollution and safety hazards: The direct emission of untreated crankcase mixture into the engine compartment not only pollutes the environment, but may also cause fires or explosions due to the accumulation of oil and gas.

[0011] 3. Limited functionality: Traditional breathers cannot actively regulate crankcase pressure and do not have auxiliary ventilation capabilities, especially under high engine load conditions, when the oil-gas concentration and positive pressure in the crankcase are relatively high.

[0012] While some existing improvement solutions attempt to actively reduce crankcase pressure by adding fans or negative pressure structures, they generally suffer from problems such as complex structures, insufficient negative pressure stability, and low oil-gas separation efficiency, making it difficult to meet the reliability requirements of long-term ship operation. Furthermore, electric motor-driven fans generate electrical sparks, posing a safety hazard in areas where oil and gas accumulate (especially in natural gas engines). Summary of the Invention

[0013] The technical problem to be solved by this utility model is to provide an active crankcase negative pressure breathing device for an engine that is simple in structure, safe and reliable, and can actively extract and separate the mixed gas in the crankcase, in light of the current status of the prior art.

[0014] The technical solution adopted by this utility model to solve the above-mentioned technical problems is as follows: An active crankcase negative pressure breathing device for an engine includes a breather housing mounted on the crankcase via a crankcase cover plate, and an oil-gas separation device with a sealing cover mounted on the upper opening of the breather housing. A centrifugal filter device, utilizing centrifugal force to filter and remove impurities from the engine oil, is installed inside the breather housing. The centrifugal filter device is driven to rotate by the engine oil pressure, and simultaneously drives a fan device for extracting the mixed oil and gas from the crankcase. The mixed oil and gas discharged by the fan device enters the oil-gas separation device and is decelerated, condensed, and separated. The separated gas from the mixed oil and gas is discharged into the atmosphere, and the condensed oil from the mixed oil and gas flows back into the crankcase. The bottom of the breather housing is formed with an oil supply channel for supplying pressurized engine oil, and an oil quantity control device is installed in the oil supply channel that automatically adjusts the opening size of the oil inlet according to changes in engine oil pressure.

[0015] To optimize the above technical solution, the specific measures also include: An annular baffle is formed in the inner cavity of the aforementioned respirator housing. The cavity above the annular baffle forms an exhaust chamber that connects to the oil-gas separator, and the cavity below the annular baffle forms an oil return chamber. The oil return chamber is connected to the crankcase via a crankcase cover plate. A bottom protrusion ring is also formed on the bottom surface of the oil return chamber. The bottom protrusion ring cooperates with the bottom of the centrifugal filter device to form an oil discharge chamber for discharging the press oil after operation. An oil discharge hole is formed at the bottom of the oil discharge chamber for connecting the oil discharge chamber and the oil return chamber.

[0016] The above-mentioned oil-gas separation device consists of a bellows, a conical filter, a breather cover, a return oil pipe, a chuck, and a clamp. The conical filter is installed inside the bellows, and the exhaust port and air inlet of the bellows are both fixed with chucks by clamps. The chuck on the air inlet of the bellows is welded and fixed to the breather cover, which covers the upper opening of the breather housing. The return oil pipe passes through the annular partition of the breather cover and the breather housing in sequence to guide the oil separated by the oil-gas separation device into the return oil chamber of the breather housing (2).

[0017] Multiple conical filters are arranged sequentially inside the corrugated pipe; an annular oil collection groove is formed on the breather cover to collect the separated oil, and the upper end of the return oil pipe is connected to the annular oil collection groove; two semi-circular holes are formed in the inner circle of the annular oil collection groove to allow the oil and gas discharged from the exhaust chamber to enter the oil and gas separation device, and a crossbeam is formed between the two semi-circular holes.

[0018] The aforementioned oil supply channel consists of a first longitudinal hole, a second longitudinal hole, and a horizontal valve hole; a throat is formed between the first and second longitudinal holes, and the horizontal valve hole connects to the throat; an oil quantity control device is installed in the horizontal valve hole, which consists of a valve block, a spring, and a plug; the plug is spirally sealed in the outer port of the horizontal valve hole, and the valve block is pressed and sealed in the throat by the spring to control the connection and disconnection between the first and second longitudinal holes; the second longitudinal hole is formed at the center position inside the bottom convex ring.

[0019] The centrifugal filter device described above is assembled from a central shaft, a connecting shaft, and a rotor assembly. The lower end of the central shaft is spirally installed in the second longitudinal hole of the respirator housing. A central oil passage axially communicating with the second longitudinal hole is machined inside the central shaft. The upper end of the central shaft is spirally connected to the connecting shaft. The upper end of the connecting shaft passes through the central hole formed by the I-shaped crossbeam and is then locked and fixed to the respirator cover plate as a whole by a thin nut. The rotor assembly is rotatably mounted on the central shaft.

[0020] The aforementioned rotor assembly consists of a rotor, an inner cover, and a filter cartridge. The rotor is rotatably supported on the central shaft via an upper and lower bushing. A locking nut for preventing axial movement of the rotor is screwed onto the shaft. The inner cover is inverted on the inner ring stop formed by the rotor, and the filter cartridge is inverted on the outer ring stop formed by the rotor. The upper end of the filter cartridge is screwed and clamped to the rotor by a locking nut.

[0021] The rotor is formed with four oil channels in equal arcs; radial oil holes are formed on the central shaft to allow oil in the central oil channel to flow into the oil channel; a centrifugal chamber is formed between the inner cover and the filter cartridge to allow impurities to be separated from the oil under centrifugal force, and an oil outlet is formed on the inner cover to connect the oil channels and the centrifugal chamber; an oil collecting chamber is provided between the inner cover and the rotor, and a top oil channel is provided between the upper end of the inner cover and the top wall of the filter cartridge to allow oil in the centrifugal chamber to enter the oil collecting chamber; an oil spray port is radially arranged below the rotor to spray oil in the oil collecting chamber into the oil discharge chamber.

[0022] The inner wall of the filter cartridge is evenly distributed with ribs, which are thicker at the top and thinner at the bottom; the central shaft is also formed with a lubrication oil passage for providing lubricating oil to the upper and lower bushings, and the lubrication oil passage is radially connected to the central oil passage.

[0023] The aforementioned fan device is a cylindrical annular fan consisting of fan blades, an upper connecting plate, and a bottom annular plate. Multiple fan blades are evenly welded onto the bottom annular plate, and the upper connecting plate is welded and fixed to the upper end of the fan blades. The upper connecting plate is tightened and fixed to the locking nut by connecting bolts.

[0024] Compared with existing technologies, this utility model's negative pressure breathing device has an oil volume control device installed in the oil supply channel that automatically adjusts the oil inlet opening according to changes in oil pressure. The inner cavity of the breathing device housing contains a centrifugal filter that uses centrifugal force to remove impurities from the oil. The centrifugal filter also simultaneously drives a fan device to extract the oil-gas mixture from the crankcase. The oil-gas mixture discharged by the fan device enters an oil-gas separator where it is slowed, condensed, and separated. This utility model's negative pressure breathing device can adaptively adjust the crankcase pressure under different engine operating conditions. Under high operating conditions, the crankcase pressure is high, the oil pump speed is high, the amount of oil flowing through the centrifugal filter device is large, and the negative pressure capacity generated by the fan device is also high. The negative pressure generated by the fan device can efficiently extract the oil-gas mixture from the crankcase, creating negative pressure within the crankcase. This negative pressure reduces the concentration of the air-fuel mixture inside the crankcase, lowering the risk of explosion and the energy of an explosion. At the same time, the negative pressure inside the crankcase can eliminate the possibility of the mixture containing lubricating oil leaking out through the gaps between the front and rear ends of the crankshaft and uneven areas such as the crankcase cover and camshaft cover, by taking advantage of the pressure difference between the inside and outside. This also eliminates the phenomenon that the leaked mixture will condense into oil stains when it encounters the relatively cool external environment, thus keeping the engine surface clean.

[0025] Under low operating conditions, although the oil pump speed is low and the oil flow rate is small, the centrifugal filter and fan rotate slowly, resulting in a limited ability to create negative pressure. However, due to the low leakage in the combustion chamber and the low pressure inside the crankcase under low operating conditions, negative pressure can still be created. The fan device in this invention also has the following advantages: 1. There is no need to install additional motors and fans for crankcase ventilation, which saves costs and space, and simplifies the engine's external piping. 2. With no ignition point, crankcase ventilation is safer and more reliable, making it ideal for engines with flammable gases in the crankcase, such as natural gas engines and methanol engines.

[0026] 3. No manual operation is required; the engine will start automatically once started.

[0027] 4. The power source for the negative pressure fan device is the oil pressure from the engine's pump. Therefore, this structure can automatically adjust the fan speed according to the engine speed, always keeping the negative pressure in the crankcase within a stable range. Attached Figure Description

[0028] Figure 1 This is a schematic diagram of a traditional respirator with a condenser structure. The attached figures are labeled as follows: condenser 71, breather body 72, drain port 73, crankcase connecting flange 74, condenser flange 75, and exhaust flange 76.

[0029] Figure 2 This is a schematic diagram of a traditional respirator with a cooling plate structure. The attached figures are labeled as follows: first straight pipe 81, second straight pipe 82, third straight pipe 83, cooling plate assembly 84, baffle 85, and drain outlet 86.

[0030] Figure 3 yes Figure 2 Schematic diagram of the middle cooling plate assembly; The attached diagrams are labeled as follows: support rod 841, cooling plate 842.

[0031] Figure 4 This is a schematic diagram of the structure of this utility model; Figure 5 This is a schematic diagram of the structure of the oil-gas separation device of this utility model; Figure 6 This is a schematic diagram of the structure of the oil quantity control device of this utility model assembled in the respirator housing; Figure 7 This is a schematic diagram of the centrifugal filter device of this utility model; Figure 8This is a schematic diagram of the device structure of the fan device and centrifugal filter device of this utility model.

[0032] Figures 4 to 8 The reference numerals in the attached drawings are as follows: connecting bolt L, thin nut M1, anti-loosening nut M2, locking nut M3, crankcase 1, crankcase cover 11, breather housing 2, exhaust chamber 2a, oil return chamber 2b, oil drain chamber 2c, oil drain hole 2d, first longitudinal hole 2e, second longitudinal hole 2f, horizontal valve hole 2g, annular partition 21, bottom protruding ring 22, oil-gas separator 3, bellows 31, conical filter screen 32, breather cover 33, annular oil collection groove 33a, semi-circular hole 33b, straight crossbeam 331, oil return... Pipe 34, chuck 35, clamp 36, plug 37, centrifugal filter device 4, centrifugal chamber 4a, oil collection chamber 4b, central shaft 41, central oil passage 41a, radial oil hole 41b, lubricating oil passage 41c, connecting shaft 42, rotor 43, oil passage 43a, oil spray nozzle 43b, inner cover 44, filter cartridge 45, rib plate 451, upper bushing 46, lower bushing 47, fan device 5, fan blade 51, upper connecting plate 52, bottom ring plate 53, oil quantity control device 6, valve block 61, spring 62, plug 63. Detailed Implementation

[0033] The embodiments of this utility model will be described in further detail below with reference to the accompanying drawings.

[0034] Figures 4 to 8 This is a schematic diagram of the structure of this utility model. like Figures 4 to 8As shown, this utility model discloses an active crankcase negative pressure breathing device for an engine, including a crankcase 1, a breather housing 2, and an oil-gas separator 3. A crankcase cover plate 11 is fixedly installed on the crankcase 1, and the crankcase cover plate 11 has breathing and oil return channels formed in it, communicating with the inside of the crankcase 1. The breather housing 2 is connected to the crankcase cover plate 11 and is installed on the crankcase 1 through the crankcase cover plate 11. The breather housing 2 has an upper opening, and the sealing cover of the oil-gas separator 3 is installed on the upper opening of the breather housing 2. A diversion centrifugal filter device 4 is installed in the inner cavity of the breather housing 2. The rotation driving force of the centrifugal filter device 4 is driven by the pressure of the engine oil. The centrifugal filter device 4 can use the centrifugal force generated by its rotation to filter and remove impurities contained in the engine oil, thereby maintaining the cleanliness of the engine oil. While the centrifugal filter device 4 is rotating, it also drives a fan device 5 simultaneously. The fan unit 5 is used to extract the mixed oil and gas in the crankcase 1 through the breather and oil return channels formed in the crankcase cover plate 11, creating negative pressure inside the crankcase 1 to prevent the risk of explosion and oil leakage due to increased pressure caused by the accumulation of oil and gas inside the crankcase 1. The mixed oil and gas discharged by the fan unit 5 directly enters the oil-gas separator 3, where it is slowed down, condensed, and separated. The gas separated from the mixed oil and gas is discharged into the atmosphere through the exhaust port at the upper end of the oil-gas separator 3, while the engine oil separated from the mixed oil and gas can flow back into the crankcase 1 through the breather and oil return channels of the crankcase cover plate 11. Figure 6 As shown, the bottom of the breather housing 2 is also formed with an oil supply channel. The pressurized oil used to drive the centrifugal filter device 4 to rotate is supplied through this oil supply channel, and the port of the oil supply channel is connected to an oil pipe. The oil supply channel of this utility model is also equipped with an oil quantity control device 6. When the oil pressure is less than the set spring pressure, the oil quantity control device 6 can close the oil supply channel. When the oil pressure is greater than the set spring pressure, the oil quantity control device 6 can automatically adjust the opening of the oil inlet according to the change of oil pressure. That is, the greater the oil pressure, the larger the opening of the oil quantity control device 6, and the more oil is supplied.

[0035] In the embodiments, such as Figure 4 and Figure 6As shown, an annular partition 21 is formed in the inner cavity of the breather housing 2, dividing the inner cavity of the breather housing 2 into upper and lower cavities. The cavity above the annular partition 21 forms an exhaust cavity 2a that connects to the oil-gas separator 3, while the cavity below the annular partition 21 forms an oil return cavity 2b. The oil return cavity 2b is connected to the crankcase 1 via the breather and oil return channels of the crankcase cover plate 11. A bottom protrusion ring 22 is also formed on the bottom surface of the inner cavity of the oil return cavity 2b. This bottom protrusion ring 22 cooperates with the bottom of the centrifugal filter device 4 to form an oil discharge cavity 2c for discharging the press oil after operation. An oil discharge hole 2d is formed at the bottom of the oil discharge cavity 2c for connecting the oil discharge cavity 2c and the oil return cavity 2b.

[0036] In the embodiments, as shown Figure 5 As shown, the oil-gas separator 3 is assembled from a bellows 31, a conical filter 32, a breather cover 33, an oil return pipe 34, a chuck 35, and a clamp 36. Specifically, the conical filter 32 is installed inside the bellows 31, with multiple conical filters 32 arranged sequentially inside the bellows 31, preferably sequentially installed on each consecutive wave of the bellows 31. The conical filter 32 is used to condense and separate the mixed oil and gas discharged from the fan unit 5. The condensed oil flows along the conical surface of the filter 32 onto the inner wall of the bellows 31. The exhaust port at the upper end and the air inlet at the lower end of the bellows 31 are both secured to the chuck 35 by the clamp 36. The exhaust port at the upper end of the bellows 31 can be easily connected to an external exhaust pipe via a chuck 35. The chuck 35 on the air inlet of the bellows 31 is welded and fixed to the breather cover 33, which in turn mates with the upper opening of the breather housing 2. The entire oil-gas separator 3 is fixedly installed on the upper opening of the breather housing 2 via the breather cover 33, and a plug 37 is also installed on the breather cover 33. The oil return pipe 34 of this invention passes sequentially through the breather cover 33 and the annular partition 21 of the breather housing 2, guiding the oil separated by the oil-gas separator 3 into the oil return chamber 2b of the breather housing 2.

[0037] To facilitate the collection of engine oil flowing down the inner wall of the bellows 31, an annular oil collecting groove 33a is formed on the breather cover 33 to collect the condensed engine oil. The lower end of the chuck 35 on the air inlet of the bellows 31 is welded and fixed in the annular oil collecting groove 33a. A hole is formed in the annular oil collecting groove 33a to allow the return oil pipe 34 to pass through. The upper end of the return oil pipe 34 is connected to the annular oil collecting groove 33a through this hole, allowing the engine oil in the annular oil collecting groove 33a to flow along the return oil pipe 34 into the return oil chamber 2b of the breather housing 2, and finally back into the crankcase. Figure 5It can also be seen that, in the inner ring of the annular oil collecting groove 33a, two semi-circular holes 33b are formed. The semi-circular holes 33b are used to allow the mixed oil and gas discharged from the exhaust chamber 2a to enter the oil-gas separator 3 through the holes. A straight beam 331 is formed between the two semi-circular holes 33b, and a central hole is machined in the center of the straight beam 331.

[0038] In the embodiments, as shown Figure 6 As shown, the oil supply channel of this utility model consists of a first longitudinal hole 2e, a second longitudinal hole 2f, and a horizontal valve hole 2g. A throat is formed between the first longitudinal hole 2e and the second longitudinal hole 2f, and the horizontal valve hole 2g connects to the throat.

[0039] The oil quantity control device 6 of this invention is installed in the horizontal valve orifice 2g. This device 6 consists of a valve block 61, a spring 62, and a plug 63. The plug 63 spirally seals the outer port of the horizontal valve orifice 2g to prevent oil leakage. The valve block 61 is pressed and sealed in the throat by the spring 62, controlling the flow between the first longitudinal orifice 2e and the second longitudinal orifice 2f. The second longitudinal orifice 2f is formed at the center position within the bottom protruding ring 22. When the oil pressure in the first longitudinal orifice 2e is higher than the spring force of the spring 62, the oil can push the valve block 61 to compress the spring 62, moving it to the right to open the throat, allowing oil to enter the second longitudinal orifice 2f through the throat. Furthermore, the greater the oil pressure, the greater the distance the valve block 61 moves to the right, and the larger the angle at which the throat opens. Therefore, the oil quantity control device 6 can automatically adjust the opening of the oil inlet according to changes in oil pressure.

[0040] In the embodiments, as shown Figure 7 As shown, the centrifugal filter device 4 of this utility model is assembled from a central shaft 41, a connecting shaft 42, and a rotor assembly. The lower end of the central shaft 41 is screwed into the second longitudinal hole 2f of the respirator housing 2, and a central oil passage 41a axially communicating with the second longitudinal hole 2f is machined inside the central shaft 41. The upper end of the central shaft 41 is screwed to the connecting shaft 42, and the upper end of the connecting shaft 42 passes through the central hole formed by the I-shaped crossbeam 331, and then the connecting shaft 42 is locked and fixed to the respirator cover plate 33 as a whole by a thin nut M1. The rotor assembly is rotatably mounted on the central shaft 41.

[0041] The rotor assembly consists of a rotor 43, an inner cover 44, and a filter cartridge 45. The rotor 43 is rotatably supported on the central shaft 41 via an upper bushing 46 and a lower bushing 47. A locking nut M2 for preventing axial movement of the rotor 43 is screwed onto the connecting shaft 42. The inner cover 44 is inverted onto the inner ring stop formed by the rotor 43, and the filter cartridge 45 is inverted onto the outer ring stop formed by the rotor 43. The upper end of the filter cartridge 45 is screwed and clamped to the rotor 43 by a locking nut M3. The outer circumferential surface of the upper end of the rotor 43 is machined with external threads that can engage with the locking nut M3.

[0042] In this embodiment, the rotor 43 of this invention has four oil channels 43a formed with equal arcs; the central shaft 41 has radially formed radial oil holes 41b that allow oil in the central oil channel 41a to flow into the oil channels 43a. A centrifugal chamber 4a is formed between the inner cover 44 and the filter cartridge 45, and an oil outlet is formed on the inner cover 44 to connect the oil channels 43a and the centrifugal chamber 4a. Thus, oil can be sprayed into the centrifugal chamber from the central oil channel 41a, the radial oil holes 41b, the oil channels 43a, and the oil outlet of the inner cover 44. When the rotor 43 rotates, the oil entering the centrifugal chamber 4a experiences centrifugal force, causing impurities and particles to be adsorbed onto the inner wall of the filter cartridge 45. While being adsorbed, the impurities and particles also move downwards and accumulate below the filter cartridge 45 and the inner cover 44. This achieves centrifugal filtration, keeping the oil clean and extending its lifespan.

[0043] The present invention further includes an oil collecting chamber 4b between the inner cover 44 and the rotor 43. A top oil passage is provided between the upper end of the inner cover 44 and the top wall of the filter cartridge 45, allowing the oil in the centrifugal chamber 4a to enter the oil collecting chamber 4b. An oil spray nozzle 43b, connected to the oil collecting chamber 4b, is radially arranged below the rotor 43. Thus, when the centrifugal chamber 4a is full of oil, the oil in the centrifugal chamber 4a can enter the oil collecting chamber 4b between the inner cover 44 and the rotor 43 through the top oil passage at the upper end of the inner cover 44, and finally be sprayed out from the oil spray nozzle 43b into the oil discharge chamber 2c, thereby driving the rotor 43 to rotate.

[0044] In this embodiment, the inner wall of the filter cartridge 45 of this invention is evenly distributed with ribs 451, which are thicker at the top and thinner at the bottom, so that the adsorbed impurities and particles can move downward along the ribs 451. The central shaft 41 of this invention is also formed with a lubrication oil passage 41c for providing lubricating oil to the upper bushing 46 and the lower bushing 47, and the lubrication oil passage 41c is radially connected to the central oil passage 41a.

[0045] like Figure 8 As shown, the fan device 5 of this utility model is a cylindrical annular fan composed of fan blades 51, an upper connecting plate 52, and a bottom annular plate 53. Multiple fan blades 51 are evenly welded onto the bottom annular plate 53, and the upper connecting plate 52 is welded and fixed to the upper end of the fan blades 51. The fan device 5 is fitted around the outer periphery of the centrifugal filter device 4. The upper connecting plate 52 is screwed onto the centrifugal filter device 4 via connecting bolts L and locking nuts M3, thus fixing the fan device 5 onto the centrifugal filter device 4. Therefore, the centrifugal filter device 4 can synchronously drive the fan device 5 to rotate, forming an upward airflow within the exhaust chamber 2a of the breather housing 2. This carries the mixed oil and gas in the crankcase 1 towards the oil-gas separator 3, and the separated gas is finally discharged into the atmosphere, creating a negative pressure inside the crankcase.

[0046] A method for evacuating air from an active crankcase negative pressure breathing device for an engine is as follows: When the engine is running, the engine oil circulates in the lubrication system under the action of the oil pump and builds up oil pressure. One path of pressurized oil enters the oil supply channel of the breather housing 2 through the oil pipe. This path of pressurized oil acts on the oil quantity control device 6 in the oil supply channel, causing the oil quantity control device 6 to open and enter the central oil passage 41a of the central shaft 41 of the split centrifugal filter device 4. The central oil passage 41a is connected to the radial oil hole 41b and the lubricating oil passage 41c. The oil entering the lubricating oil passage 41c can form a good lubricating oil film between the upper bushing 46 and the lower bushing 47. The oil entering the radial oil hole 41b can be directly sprayed into the centrifugal chamber 4a of the centrifugal filter device 4 through the oil passage 43a of the rotor 43 and the oil outlet of the inner cover 44. After the centrifugal chamber 4a is full of oil, the overflowing oil can enter the oil collection chamber 4b between the inner cover 44 and the rotor 43 from the top oil passage at the upper end of the inner cover 44. Finally, it is sprayed out from the radially arranged oil nozzle 43b below the rotor 43, thereby driving the rotor 43 to rotate. After the rotor 43 rotates, the oil inside the filter cartridge 45 is subjected to centrifugal force. Impurities and particles with larger masses are thrown onto the inner wall of the filter cartridge 45 due to the greater centrifugal force. At the same time, because the filter cartridge 45 has evenly distributed ribs 451 with coarser upper sections and thinner lower sections, impurities and particles are not only adsorbed but also move downwards along the ribs 451 and accumulate at the bottom of the filter cartridge 45 and the inner cover 44. This achieves centrifugal filtration, keeping the oil clean and extending its lifespan.

[0047] When the split-flow centrifugal filter device 4 starts working, the fan device 5 fixed on the rotor assembly of the centrifugal filter device 4 also starts rotating, forming an outward and upward airflow. This causes the mixed oil and gas in the crankcase 1 to be carried by the airflow generated by the fan device 5 and blown towards the oil-gas separator 3, creating a negative pressure in the crankcase 1. The mixed oil and gas is filtered and condensed by the multi-layer conical filter screen 32 in the oil-gas separator 3. The resulting oil flows along the conical surface of the conical filter screen 32 to the inner wall of the bellows 31, and then flows down the inner wall to the annular oil collection groove 33a on the breather cover plate 33. It then flows through the oil return pipe 34 to the oil return chamber 2b of the breather housing 2, and finally mixes with the clean oil discharged from the split-flow centrifugal filter device 4 before flowing back to the oil pan in the crankcase.

[0048] The above embodiments provide a systematic and detailed description of the present utility model. These are merely preferred embodiments of the present utility model and are not intended to limit the present utility model. For those skilled in the art, the present utility model can have various modifications and variations. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present utility model should be included within the protection scope of the present utility model.

Claims

1. An active crankcase negative pressure breathing device for an engine, comprising a breather housing (2) mounted on a crankcase (1) via a crankcase cover plate (11), and an oil-gas separation device (3) with a sealing cover mounted on the upper opening of the breather housing (2); characterized in that: The inner cavity of the breather housing (2) is equipped with a centrifugal filter device (4) that uses centrifugal force to filter and remove impurities contained in the engine oil; the centrifugal filter device (4) is driven to rotate by the engine oil pressure, and the centrifugal filter device (4) also drives a fan device (5) for extracting the mixed oil and gas in the crankcase (1); the mixed oil and gas discharged by the fan device (5) enters the oil-gas separator (3) and is decelerated, condensed and separated; the gas separated from the mixed oil and gas is discharged into the atmosphere, and the oil separated from the mixed oil and gas flows back into the crankcase (1); the bottom of the breather housing (2) is formed with an oil supply channel for supplying pressurized engine oil, and an oil quantity control device (6) is installed in the oil supply channel that can automatically adjust the opening of the oil inlet according to the changes in the oil pressure.

2. The active crankcase negative pressure breathing device for an engine according to claim 1, characterized in that: An annular partition (21) is formed in the inner cavity of the respirator housing (2). The cavity above the annular partition (21) forms an exhaust cavity (2a) that connects to the oil-gas separator (3). The cavity below the annular partition (21) forms an oil return cavity (2b). The oil return cavity (2b) is connected to the crankcase (1) via the crankcase cover plate (11). The bottom surface of the oil return cavity (2b) is also formed with a bottom protrusion ring (22). The bottom protrusion ring (22) cooperates with the bottom of the centrifugal filter device (4) to form an oil discharge cavity (2c) for discharging the press oil after operation. The bottom of the oil discharge cavity (2c) is formed with an oil discharge hole (2d) for connecting the oil discharge cavity (2c) and the oil return cavity (2b).

3. The active crankcase negative pressure breathing device for an engine according to claim 2, characterized in that: The oil-gas separation device (3) consists of a bellows (31), a conical filter (32), a breather cover (33), a return oil pipe (34), a chuck (35), and a clamp (36). The conical filter (32) is installed inside the bellows (31). The exhaust port and air inlet of the bellows (31) are both fixed with a chuck (35) by clamp (36). The chuck (35) on the air inlet of the bellows (31) is welded and fixed to the breather cover (33), which covers the upper opening of the breather housing (2). The return oil pipe (34) passes through the breather cover (33) and the annular partition (21) of the breather housing (2) in sequence to guide the oil separated by the oil-gas separation device (3) into the return oil chamber (2b) of the breather housing (2).

4. The active crankcase negative pressure breathing device for an engine according to claim 3, characterized in that: The corrugated pipe (31) is provided with multiple conical filter screens (32) arranged in sequence from top to bottom; the breather cover plate (33) is formed with an annular oil collecting groove (33a) for collecting the separated oil, and the upper end of the return oil pipe (34) is connected to the annular oil collecting groove (33a); the inner circle of the annular oil collecting groove (33a) is formed with two semi-circular holes (33b) for allowing the oil and gas discharged from the exhaust chamber (2a) to enter the oil and gas separation device (3), and a straight beam (331) is formed between the two semi-circular holes (33b).

5. An active crankcase negative pressure breathing device for an engine according to claim 4, characterized in that: The oil supply channel is composed of a first longitudinal hole (2e), a second longitudinal hole (2f), and a horizontal valve hole (2g); a throat is formed between the first longitudinal hole (2e) and the second longitudinal hole (2f), and the horizontal valve hole (2g) is connected to the throat; the oil quantity control device (6) is installed in the horizontal valve hole (2g), and the oil quantity control device (6) is composed of a valve block (61), a spring (62), and a plug (63); the plug (63) is spirally sealed in the outer port of the horizontal valve hole (2g), and the valve block (61) is pressed and sealed in the throat by the spring (62) to control the opening and closing between the first longitudinal hole (2e) and the second longitudinal hole (2f); the second longitudinal hole (2f) is formed in the center position of the bottom protruding ring (22).

6. The active crankcase negative pressure breathing device for an engine according to claim 2, characterized in that: The centrifugal filter device (4) is assembled from a central shaft (41), a connecting shaft (42), and a rotor assembly. The lower end of the central shaft (41) is spirally installed in the second longitudinal hole (2f) of the respirator housing (2). The central shaft (41) has a central oil passage (41a) that axially connects to the second longitudinal hole (2f). The upper end of the central shaft (41) is spirally connected to the connecting shaft (42). The upper end of the connecting shaft (42) passes through the central hole formed by the crossbeam (331) and is locked and fixed to the respirator cover plate (33) by a thin nut (M1). The rotor assembly is rotatably mounted on the central shaft (41).

7. An active crankcase negative pressure breathing device for an engine according to claim 6, characterized in that: The rotor assembly consists of a rotor (43), an inner cover (44), and a filter cartridge (45). The rotor (43) is rotatably supported on the central shaft (41) via an upper bushing (46) and a lower bushing (47). A locking nut (M2) for preventing axial movement of the rotor (43) is screwed onto the connecting shaft (42). The inner cover (44) is upside down on the inner ring stop formed by the rotor (43), and the filter cartridge (45) is upside down on the outer ring stop formed by the rotor (43). The upper end of the filter cartridge (45) is screwed and clamped to the rotor (43) by a locking nut (M3).

8. An active crankcase negative pressure breathing device for an engine according to claim 7, characterized in that: The rotor (43) has four oil channels (43a) formed at equal arcs; the central shaft (41) has radially formed radial oil holes (41b) that allow oil in the central oil channel (41a) to flow into the oil channels (43a); a centrifugal chamber (4a) is formed between the inner cover (44) and the filter cartridge (45) to separate impurities from the oil under centrifugal force, and the inner cover (44) has formed a channel for connecting the oil. The channel (43a) and the oil outlet of the centrifugal chamber (4a); an oil collecting chamber (4b) is provided between the inner cover (44) and the rotor (43), and a top oil passage is provided between the upper end of the inner cover (44) and the top wall of the filter cartridge (45) to allow the oil in the centrifugal chamber (4a) to enter the oil collecting chamber (4b); an oil spray port (43b) is radially arranged below the rotor (43) to spray the oil in the oil collecting chamber (4b) into the oil discharge chamber (2c).

9. An active crankcase negative pressure breathing device for an engine according to claim 8, characterized in that: The inner wall of the filter cartridge (45) is evenly distributed with ribs (451), which are thicker at the top and thinner at the bottom; the central shaft (41) is also formed with a lubricating oil passage (41c) for providing lubricating oil to the upper bushing (46) and the lower bushing (47), and the lubricating oil passage (41c) is radially connected to the central oil passage (41a).

10. An active crankcase negative pressure breathing device for an engine according to claim 9, characterized in that: The fan device (5) is a cylindrical annular fan composed of fan blades (51), an upper connecting plate (52) and a bottom annular plate (53); multiple fan blades (51) are uniformly welded on the bottom annular plate (53), and the upper connecting plate (52) is welded and fixed to the upper end of the fan blades (51). The upper connecting plate (52) is pressed and fixed on the locking nut (M3) by connecting bolts (L).

Images