Two-stroke internal combustion engine

FIELD: mechanical engineering.

SUBSTANCE: invention relates to two stroke internal combustion crankcase compression engine designed for use in hand tools. According to invention, engine has at least one air channel between air intake and upper part, two scavenging channels with scavenging ports directed to side of discharge and located close to exhaust hole of cylinder. Engine has at least one scavenging port pointed to side of intake and located close of intake port of cylinder, delivery to said port being provided by at least one scavenging channel. Air channel and scavenging channels are of such design that such amount of air is fed and held in scavenging channels that nothing but air will get out during following scavenging process. Air intake from which air channel branches if provided with limiting valve controlled by at least one parameter of engine, for instance, under action of throttle valve of carburetor. Scavenging ports(s) pointed to side of intake is (are) arranged to provide beginning of delivering of air-fuel mixture later than scavenging with air through scavenging ports pointed to side of exhaust.

EFFECT: reduced consumption of fuel and discharge of noncombusted fuel with exhaust gases.

16 cl, 5 dwg

 

The technical field to which the invention relates.

Considering the invention relates to two-stroke internal combustion engine with scavenging of crankcase having at least one cylinder and one air channel located between the air inlet and the upper part of the at least two vent channels with vent Windows located close to the exhaust of the cylinder bore, and at least one directed to the intake side vent window, which is located close to the inlet of the cylinder and the flow in which is carried out using at least one vent channel or the like, and the air duct and vent channels are designed that vent channels may be filed and retained so much air that during the subsequent purging of them will not be leaving essentially nothing but air. Thus, there is fresh air in the purge channels located most close to the holes for the exhaust gases and fresh air is intended to serve as a buffer for the air-fuel mixture supplied closer to the inlet opening towards the outlet for the exhaust gases. This reduces fuel consumption and emissions from the exhaust. The engine before the aircraft is th is for hand tools.

Background of invention

Known internal combustion engines, provided with a supply of additional air into the air passages. They reduce fuel consumption and recovery of the products of combustion from exhaust gases, but in this engine it is difficult to regulate the ratio of air to fuel. In addition, a significant decrease in secretions from the exhaust gases can be difficult.

In a recently published report by the Society of automotive engineers with the reference number 2000-01-9000 described engine design similar to the one described at the beginning. Using non-return valves, so-called Reed-valve (reed valve), two vent channel closest to the exhaust outlet, is given so much air that it is enough for the whole process of purging. One or more vent channels with Windows located close to the intake side, will instead provide venting of the air-fuel mixture at the same time as other Windows will ensure the air purge. You should specify that this purging is done in parallel, that is, begins at the same time and continues throughout the process of purging. This principle is described as a layer-by-layer blowing in space. Fuel consumption and emissions from the exhaust gases Bud the t is considerably reduced compared with conventional two-stroke engine. However, at the same time, it should be noted that there will be loss of air-fuel mixture through the hole for the exhaust gases at the end of the process of purging during the time of rotation of the crank on the last 40-50 degrees before closing the holes for the exhaust gases. Obviously, this loss is undesirable. In addition, check valves are used to feed air passages located close to the hole for the exhaust gases, in a known manner. The narrowing of the cross section of flow in the reverse valve hinders the filling of the channels with air. However, valves of this type, commonly called the Reed-valves have a number of other disadvantages. They often have a tendency to enter into resonant vibrations, and at high speeds, which can reach many two-stroke engines, these valves can be difficult. In addition, this leads to additional costs and increase the number of components of the engine.

In the international patent application WO 98/57053 shows several different embodiments of the engine in which air is introduced into the purge channels through L-shaped or T-shaped recess in the piston. Thus, the check valves are missing. Air is supplied to all the purge channels and serves as a buffer against below the air-top the top of the mixture. Thus, there is an alternation of purge time and not in space, unlike the engine mentioned above. In all variants of the implementation of the recess in the piston has a very limited height in the place of its connection with the corresponding vent channel with the specified height essentially equal to the height of the real purge channel. The result of the implementation of this option is that the channel for air flow through the piston to vent the window opens much later compared to the channel for supplying air-fuel mixture in the crankcase is opened by the piston. Thus, the period of air supply significantly shorter than the period of the air / fuel mixture, however, this period can be determined using the angle or time of rotation of the crank. This can create difficulties in the regulation of the relations of the total quantity of air to the amount of fuel in the engine. This also means that the amount of air that can be added to each vent channel is significantly reduced, since the pressure that causes this addition is greatly reduced due to the fact that the inlet hole was already open for a certain period of time before the opening of the channel for air supply. This means that as the period of air supply and the driving force, causing the air supply, small. In addition, the flow resistance in the L-shaped and T-shaped channels, similar to the one shown, is quite high, partly due to the fact that the cross-section of the channel is small in area next to the vent window, and partially due to abrupt changes in flow direction caused by L-shaped or T-shaped. When air enters the purge window, immediately the direction of its flow is forcibly changed dramatically in the direction from the transverse direction of the cylinder so that instead of the lateral direction of the air will pass through the purge channel outwards and then downwards, i.e. the two curves at an angle of 90° consistently with the rapid change of direction. This is because the air passages of the engine are held in radial direction with respect to the cylinder. All this helps to increase the flow resistance and reducing the amount of air that can be added to the purge channels, which reduces the possibility of reducing fuel consumption and emissions of exhaust gases due to the use of this design.

The objective of the invention

The task under consideration of the invention is to significantly alleviate the above problems and achieve benefits in many ways.

Summary of the invention

You upomyanuta problem is solved using a two-stroke internal combustion engine according to the invention, having distinctive characteristics specified in the attached claims.

Thus, the internal combustion engine according to the invention is a two-stroke internal combustion engine with scavenging of crankcase having at least one cylinder and at least one air channel located between the air inlet and the upper part of the at least two vent channels directed to the output side vent Windows located close to the exhaust of the cylinder bore, and at least one directed to the intake side vent window located close to the inlet of the cylinder, and the flow in this window by using at least one the purge channel or the like, and an air channel and air passages are so designed that in the vent channels may be filed and retained so much air that during the subsequent purging of them will not be leaving essentially nothing but air in which the air duct passes from the air intake provided with a restrictive valve, which is controlled by at least one parameter of the engine, for example, by controlling the throttle valve of the carburetor, and directed to the intake side vent is (s) window (s) thus, what it/they provide (s) the beginning of the purge air-fuel mixture later than aimed in the output side vent window start blowing air.

Each directed to the intake side vent window has an upper edge which is located below in the axial direction, that is, closer to the crankcase than the corresponding upper edge of the other of the inlet ports.

In addition, the upper portion of each vent channel directed to the intake side vent window is connected to the air intake, but is of such design that it/they will be served is adapted amount of air that this number during the subsequent process of purging will end before the end of the air directed to the output side vent Windows, so directed to the intake side vent window (s) provide (s) the beginning of the purge air-fuel mixture during the process of purging.

The inlet through at least one connecting channel is connected to at least one connection hole in the cylinder wall of the engine, which is located in such a way that it is when the piston is at top dead center point connected with grooves present in the piston, and the data deepening lead to a number of the purge channel is directed through the output side vent window.

Deepening also lead to a number of vent channels through directed into the intake side vent window.

In the engine according to the invention when the piston is in its top dead point, the distance in axial direction between the upper edge of each recess in the piston and the bottom of each sent to the intake side vent window is less than the corresponding distance for each directed towards the issue of inlet ports, so that each directed to the intake side vent window will communicate with the intake later, when the piston moves upward in the direction of its top dead point.

At least one directed to the intake side vent window vent channel is made in the form of recesses in the cylinder wall, with the deepening during the process of purging interacts with a hole in the piston, so that the purge gases will pass by the piston through the hole and the recess.

Moreover, when the piston is in its top dead point, he covers all the groove so that air cannot leak from the recess.

Connecting the bore of the cylinder and each directed to the output side vent window shifted relative to each other along the periphery of the cylinder walls, napravlenie in the output side vent Windows are essentially in the transverse direction of the cylinder from each vent window.

Each of the connecting branch, which leads to a corresponding connecting hole is directed in the transverse direction of the cylinder or slightly up from it.

The recess in the piston, which is joined with the corresponding directed to the output side vent window is located so that the air supply occurs during the period essentially equal to or greater duration, calculated as the angle of rotation of the crank or time period regarding intake.

The period of air supply is more than 90% of the period of intake, but less than 100% of the intake period.

The recess in the piston, which is joined with the corresponding directed to the output side vent window, locally this window has a height in the axial direction, which is more than 1.5 times the height of each vent window, preferably more than 2 times the height of the vent window.

The upper edge of each of the connecting holes is as high as the lower edge of each sent to the output side vent window, or higher than the lower edge of each sent to the output side vent Windows, in the axial direction of the cylinder.

At least one channel provided with a check valve that goes from the intake to the top of the range purge the channels.

In an embodiment of the engine, at least one channel provided with a check valve that goes from the intake to the top, at least one vent channel directed to the intake side vent window, and this check valve is adapted to supply a more limited air flow in comparison with non-return valves belonging to purge channels, located next to the exhaust hole of the cylinder.

As mentioned above, as directed in the intake side vent Windows provide the beginning of a purge air-fuel mixture later than by aiming at the output side vent Windows starts blowing air, the air-fuel mixture will be less time to reach the exhaust hole. Thereby, it is possible to reduce the loss of air-fuel mixture through the exhaust hole. This can be done due to the fact that the purge channels that have aimed at the intake side vent Windows, partially filled with air or exhaust gases before purging. Thus first will be the gas that will cause the delay of the passage of the air-fuel mixture by blowing. In addition towards the intake side vent window can also be located so that the corresponding upper edge is located below in the axial direction in comparison with the corresponding edge of the other of the inlet ports. Due to the fact that at least one connection opening in the wall of the cylinder of the engine is such that it is at the moment when the piston is at top dead center, is connected to the flow paths available in the piston, the supply of fresh air in the upper part of the vent channels may be implemented entirely without check valves. This can be done because in the zones near the upper dead point or near the top dead point, there is a negative pressure in the purge channel relative to the surrounding air. Therefore, thus can be implemented passage of air through the channels in the piston without any check valves, which is a big advantage. Because the air supply takes place over a very long period of time, can be added a significant amount of air, so that it can be achieved very acceptable degree of reduction of emissions from the exhaust. Management is carried out using a restrictive valve in the air intake, while this valve is controlled by using at least one parameter of the engine. This design controls is considerably less complicated design compared with an adjustable intake. The inlet preferably has two connecting channel, the cat is who in one embodiment, are thus the piston cover them in its lower dead point. Control of restrictive valve can preferably be performed using the throttling of the engine or of the engine speed, separately or in combination with another parameter of the engine.

The above and other features and advantages will become more apparent from the following detailed description of various embodiments of the invention with reference to the attached figures of drawings.

Brief description of drawings

Below the invention will be described in more detail by means of various variants of its implementation with reference to the accompanying figures of the drawings. As for the elements, which are symmetrically arranged in the engine, then the element on the one hand, was given a numerical designation, while the element located on the opposite side, was given the same designation, but with character ‘. In the drawings, elements with the symbol ‘ are located above the plane of the paper and, therefore, not visible.

Figure 1 shows a side view of the engine according to the invention. The cylinder shown in cross-section, as part of the piston, which is shown in the top dead point. Purge channels are fully or partially filled with air.

Figure 2 shows the second variant of the invention, is within the open air passages. Figure 2-5 represent detailed images, enlarged in comparison with Fig 1.

Figure 3 shows a third variant embodiment of the invention, having directed in the direction of the intake air passages are made in the form of recesses in the cylinder wall communicating with the grooves in the piston. Air passages are filled with air.

Figure 4 shows the purge channel of the same type as figure 3, but in this case the air in the channel is not filed.

Figure 5 shows the purge channel of this type, which is used as the only blowing channel, and therefore it is located directly above the intake channel of the engine.

Description of embodiments

In figure 1 reference number 1 denotes an internal combustion engine according to the invention. He is a two-stroke engine type and has a vent channels 3, 3’. Channel 3’ is not visible because it is located above the plane of the paper. The engine has a cylinder 15 and the crankcase 16 of the engine, the piston 13 with the connecting rod 17 and the crank mechanism 18. In addition, the engine has an inlet port 22 with the inlet hole 33 and the intermediate part 24 connected to the inlet channel, with this part, in turn, is connected with the carburetor 25 with the throttle 26. Fuel 37 is fed through a carburetor. Usually the carburetor is connected to the input muffler with what omashu filter. This is not shown for clarity of the image. The same applies to the exhaust outlet and the muffler of the engine. These elements are conventional in all respects. Channels 3, 3’ to move are directed towards the release of Windows 9, 9’ in the wall 12 of the cylinder of the engine, located close to the exhaust hole 19 of the cylinder. The engine has a chamber 32 of combustion from the spark plug which is not shown. All this is conventional and therefore will not be described in more detail.

The distinguishing feature is that the inlet 2 provided with a restrictive valve 4, is located so that fresh air can be enjoyed in the cylinder. The inlet 2 has a connecting channel 6 leading to the cylinder, which is made with an outer connecting hole 7. Under the connecting hole with the given descriptions refers to the connecting hole on the inner side of the cylinder, while the cylinder hole on the outer side of the cylinder is called the external connecting hole. The inlet 2 is properly connected to the input muffler with filter, which is provided by the absorption of purified fresh air. If the requirements below, of course, this need will be missing. Input muffler not shown for clarity.

the thus, the the connecting channel 6 is connected to the external connecting hole 7. This is an advantage. At or after this hole channel is divided into two branches 11, 11’, each of which leads to a corresponding connecting hole 8, 8’. These elements are symmetrical, and the elements with the symbol ‘, as described above, are located above the plane of the paper. Thus, the outer connecting hole is located below the inlet port 22, which provides a number of advantages, such as lower temperatures and better use of space for hand tools.

However, the outer communication hole 7 can also be located over the inlet channel 22, which in this case is directed more horizontally. You can use the two connecting holes 7, 7’, wherever they were located. Thus, they can also be located on each side of the intake channel 22. Therefore, the inlet channel for the air passes through at least one connecting channel 6, 6’ to at least one of the connecting holes 8, 8’.

The recesses 10, 10’ in the piston forming the flow path, are located in the piston in such a way that they are when the piston is at top dead center provide the connection of the respective connecting holes 8, ’ with the upper part of the channels 3, 3’ to move, having directed towards the issue of inlet ports 9, 9’. The recesses 10, 10’ formed local recesses in the piston. The piston is made in a simple way, usually cast, with these local depressions.

Flow path also connects the air passages 5, 5’ with directed into the intake side vent Windows 14, 14’, respectively, with each connecting hole 8, 8’. The figure shows schematically how the various air passages were filled before purging. Air-fuel mixture present in the crankcase of the engine indicated by the reference number 29. It should be noted that the air-fuel mixture 29 comes to approximately half the purge channel 5. Above it is the air which has entered from the inlet 2. On the other hand, the whole the purge channel 3 is filled with air. This is necessary in order to go from directional to the output side inlet ports 9 and its corresponding window 9’ blowdown nothing but air, which serves as a buffer in relation to the exhaust outlet 19. On the other hand, directed to the inlet side of the inlet ports 14, 14’ must first be submitted to the air, and then air-fuel mixture 29. Thus there is a delay of the input air-fuel mixture that allows omensetter by blowing. As is evident from the figures, the upper edge directed toward the intake inlet ports 14, 14’ is also lower in the axial direction, that is, closer to the crankcase than the corresponding upper edge of the other of the inlet ports 9, 9’. This may help delay the process of purging sent to the intake side vent window. In this case also will be a delay of purge air, which, in turn, causes a delay of purge air-fuel mixture 29. This phenomenon depends on how high the top edge directed into the intake side vent window is concerning, on the one hand, directed to the output side of the inlet ports and, on the other hand, the exhaust hole. When the piston is in its lowered begins to open the exhaust hole, the pressure in the combustion chamber above the piston will rapidly fall, at the same time the pressure in the crankcase 16 of the motor piston will slowly increase. When the piston begins to open towards the output side inlet ports 9, 9’, there will be a flow through each window, which reduces the pressure differential between the combustion chamber and the crankcase. As the piston moves down quickly, usually often the first will be a small flow of exhaust gases into the box, then there will be the expiration of exhaust gases and air through the window in the opposite direction. By placing the upper edge directed into the intake side vent window, considerably below the upper edge directed into the output side vent window, ensure that blowing through this window will begin before the movement of the piston will begin to open directed to the intake side vent window. It is important that each vent channel 5, 5’ with the corresponding directed to the output side vent window 14, 14’ has submitted some air, which will end during the subsequent process of purging before the end of the air directed to the output side vent Windows 9, 9’. Thus, each vent channel 5, 5’ with directed into the intake side vent window 14, 14’ provides the beginning of a purge air-fuel mixture during the process of purging that is necessary in order to get the fuel to reach the combustion chamber. The amount of air-fuel mixture, which is "time" to reach the combustion chamber depends mainly, first, when will start the purge, which was discussed above, and, secondly, on how much air was lodged in the upper part of each directed to the intake side vent channel 5, 5’. This amount of air is determined by the parameters of the flow from the inlet 2 and cartradeindia in the output side inlet ports 9, 9’ and through directed into the inlet side inlet ports 14, 14’. Because a much greater amount of air must be brought in towards the output side inlet ports 9, 9’, this air flow is given priority. This is partly due to the fact that every directed to the intake side vent window will communicate with the inlet 2 later when the piston is moved in the direction of its top dead point. This is achieved because when the piston is in its top dead point, measured in an axial direction distance between the upper edge of the recess 10, 10’ in the piston and the bottom of each directed toward the intake inlet ports 14, 14’ will be less than the corresponding distance for each directed to the output side inlet ports 9, 9’. The fact that the air flow in each directed to the output side vent window 9, 9’ must occur before, also due to the fact that these Windows are made with a larger area compared to facing the intake side vent Windows 14, 14’. This is achieved mainly due to the fact that the top edge is much higher. But the bottom edge is also located below. Obviously aimed at the output side vent window can also be made wider than the human with directed into the intake side Windows. However, the flow resistance in each vent channel is also of great importance. Therefore, it is preferable that in aimed towards the production of purge channels 3, 3’ was a low flow resistance. Preferably, if aimed in the direction of release of the purge channels 3, 3’ extending from the respective inlet ports 9, 9’ essentially in the transverse direction of the cylinder, that is essentially tangentially to the circumference of the wall 12 of the cylinder. Thus, the flow occurs in the transverse direction of the cylinder from the connection holes 8, 8’ and directed to the output side vent Windows 9, 9’ and then in the same generally transverse direction at the beginning of each vent channel 3, 3’. These channels are held in the transverse direction to the output side of the cylinder, with the side of the cylinder they smoothly rotated down toward the crankcase and connected with him in the hole 20 of the crankcase. This design each vent channel 3, 3’ obvious application PCT/SE 00/00058 filed 14.01.2000. It is also clear that the corresponding directed to the intake side vent channel can be made of such form and direction. However, as directed in the intake side vent channel should have a greater resistance to flow and should not contain t is to much air, it may be preferred instead be directed towards the intake side vent channels 5, 5' down to the crankcase of the engine in the simplest way possible. Figure 1 shows a simple arrangement of the closed vent channel 5, 5’ with a hole 21, 21’ of the crankcase. However, this channel can be made even easier due to the fact that it will be opened in the direction of the cylinder throughout its length. In this case, it is preferably in the form of such axial grooves in the cylinder wall, which may be formed during casting of the cylinder under pressure. When the piston is in its top dead point, as shown in figure 1, it will close the groove in approximately one third of its length. Thus, the groove may be filled with air only up to the third. This takes into account the air that comes after top dead center, when the piston moves down and covers a large part of the groove. Compared with the closed directed to the intake side vent channel this is a limitation, which, however, also means advantage. This is due to the fact that in certain modes of engine operation, air can leak from the lower side of the piston, so that when different modes of operation of the engine is secured to a lesser extent and changing the amount of air.

The air flow in the ventilation channels may also be implemented using at least one channel provided with a check valve and passing from the inlet 2 to the top of the vent channels 3, 3’; 5, 5’. By performing the check valve belonging to the purge channel and is directed to the intake side vent window 14 with parameters different from the parameters of the check valve belonging to the purge channel located near the exhaust hole 19 of the cylinder, a smaller amount of air can be enjoyed in the purge channels directed to the intake side vent Windows. This means that the result described above can be achieved also in this way. Preferably a check valve, which belongs to the purge channel 5, is made more difficult opening, compared with non-return valve belonging to the purge channel 3. Thus, he will open later and close earlier, so that the air flow will be limited.

In the embodiment of figure 2 the purge channel 28 is located on the actual recesses 10 in the piston. This channel is designed as an open vent channel, i.e. in the form of passing in the axial direction of the grooves on the surface of the wall 12 of the cylinder. In the upper dead point of the upper side of archna is approximately flush with the upper edge of the connecting hole 8, 8’. In this case, the part of the open vent channel 28, which is located on this level is considered as the purge box 27. In this case, there are two symmetrical vent channel 28, 28’. You should pay attention to the fact that the purge channel 5 with a window 14 in figure 1 has a preferred location with respect to the exhaust outlet 19. He increasingly directed away from the exhaust holes than the purge box 27 figure 2. Even though the purge channel 28 is located on the actual recesses 10 in the piston, the air in it still can be drawn from this deepening with the provisions of the piston is close to top dead center. The figure shows two alternative systems air supply, this figure also illustrates the potential for receipt of exhaust gases down into the vent channel 28 when the piston moves down toward its bottom dead point. Three shows the solutions can be used individually or in combination of two or three solutions.

In its upper part, the purge box 27 is made with a projecting part 35, which corresponds to the recess 10 in the piston when it is close to its upper dead point. Thus the air may flow from the connecting holes 8 through increased is giving 10 and the protruding portion 35 to the top of the vent channel 28. When performing a protruding part 35 with the corresponding width in the channel 28 is adapted to enter the amount of air so that it will be filled approximately to the lower side of the piston 13. The protruding portion 34 of the recess 10 illustrates an alternative method of supplying air into the vent channel 28. In the position shown in the upper dead point and immediately before and after him, no air passes through the protruding portion 34. Obviously, this part can be located below, but for clarity it is shown as part located completely above the vent window 27. However, when the upper edge of the recess 10 is in contact with the lower side of the connecting hole 8, the air begins to flow from the protruding part 34 in the purge channel 28, and this continues until, until it is over the channel. Thus, air in the upper part of the channel 28 will be of the protruding part 34 in the same way as is used to supply air from the protruding part 35. In figure 2 the upper edge of the inlet ports 27 is shown positioned higher than the top edge directed towards the issue of inlet ports 9. This means that the piston will open the purge channel 28 before it "opens" the purge channel 3. Thus the blowing channel 28 will be created over the high pressure and will be a greater flow of exhaust gases down than in the purge channel 3. The top edge of the vent channel 28 preferably is located so high in the axial direction as the desired quantity of the exhaust gases will pass down into the vent channel 28. Adaptation may be such that the amount of exhaust gas itself provides the desired delay purge purge channel 28 of the air-fuel mixture. But adaptation can also be such that a certain amount of exhaust gases is served after previously filed number of air through the protruding portion 35 and/or 34. Since the flow of exhaust gases occurs when the piston is substantially lower compared to its position at top dead center, outdoor vent channel can be filled with exhaust gases to a lower level than it could be filled only with air, since the lower side of the piston is lower at the time of receipt of exhaust gases.

Figure 3 shows an implementation option, in which the purge box 27 has a preferred location near the vent window 9 is similar to figure 1. However, this is achieved in a completely different way. At least one directed towards the release of the purge box 27, 27’ with a vent channel 28, 28’ is made in the form of recesses 27, 28; 27’, 28’ in the cylinder wall. In the process of purging uh what about the deepening will interact with the hole 30, 30’ in the piston, so that the purge gases will pass by the piston through the hole and the recess. When the piston will be in its upper dead point, it will override all the deepening except as may be serving down part 36. Due to this part adapted fewer air-fuel mixture and air can be sucked when the piston approaches its top dead point. In the case when this protruding down portion 36 is not used, this mixture instead will remain or will be moved through the air flow down in aimed towards the release of the purge channel 3. This means that, when the piston is close to top dead center, the deepening will probably be filled with air in such quantity, what it can take. However, this amount of air is very small. The main part of the total air will instead fill the purge channels 3, 3’ next to the exhaust hole. In the process of purging the piston will be located so that its upper edge will be positioned approximately flush with the upper edge of the connecting hole 8. Thus, the hole 30 will be connected to the vent channel 28, i.e. the bottom of the recess, representing the purge channel, while the upper side is equal to the consumption will serve as inlet ports 27. You should pay attention to the fact that the upper edge of the inlet ports 27 is located substantially below the upper edge of the inlet ports 9. It means that there will be a delay in the process of purging, and he will begin then with a small amount of air, to be followed by the air-fuel mixture.

Figure 4 shows an implementation option, which in the recess 27, 28 is not receiving air from the connecting hole 8. Therefore, this recess provides the beginning of a purge air-fuel mixture directly to the moment when the piston begins to open the purge box 27. By placing the upper edge of the recesses 27, 28 particularly low can be provided with a very short and late blowing. Perhaps the top edge of the piston can be locally beveled to facilitate this. However, it should be noted that this is later than the purge box 9 will begin to open when the piston. In the recess 27, 28; 27’, 28’ air may be supplied through the protruding parts 34, 35, 36, as shown in figure 2 and 3. Its top edge can also be adapted to fill the deepening of the exhaust gases, as shown in figure 2.

Figure 5 uses only one recess 27, 28, and it is located directly above the inlet opening. If the piston is lowered in the described position in igna dead point, it becomes apparent, as the thread can pass through the hole 30 and pass the piston through the aperture 27, 28. The advantage of this option is that you only need one recess, but the disadvantage is that this deepening ends opposite the exhaust hole 19, so that there is a danger that the purge gases will penetrate into the exhaust hole earlier than in the other examples, particularly examples 1 and 3. The recess 27, 28 can be made in the inserted part, which is inserted from the outside into the cylinder, which thus can be manufactured through injection molding, resulting in cheaper cylinder. It is accordingly applicable to the examples according to Fig 3 and 4.

Usually the connecting holes 8, 8’ are arranged in such a manner in the axial direction of the cylinder that the piston closes them when it is in its bottom dead point. Thus the exhaust gases cannot penetrate into the connection hole and on through the possible air filter. But it is also possible to design, in which the connecting holes 8, 8’ are so high that they are to some extent open when the piston will be in its lower dead point. In this case, the dimensions are adjusted so that wish is inoe amount of exhaust gas will be fed into the connecting channel 6. Located high, the communication hole may also provide a means of reducing resistance to air flow when switching from the connection holes on the vent window 9.

The period of air supply from the connecting holes 8, 8’ directed to the output side vent window 9, 9’, where the air must come in the first place, is very important and to a large extent is determined by the flow paths in the piston, that is, the recess 10, 10’ in the piston.

Preferably the upper edge of the recess 10, 10’ is so high that when the piston is moved up from the lower dead point, this region reaches the lower edge of the corresponding directed to the output side inlet ports 9, 9’ at the same time or earlier than the lower edge of the piston reaches the bottom of the inlet. Thereby providing for the passage of air connection between the connecting holes 8, 8’ and vent Windows 9, 9’ is opened at the same time or earlier than opens the inlet opening. When the piston moves down after a stay in the top dead point, the connection providing passage of air, will also be closed at the same time or later than the inlet of the inlet. Thus, the air supply will occur within a period essentially equal to or greater dlitelnost is, designed in the form of a rotation angle of the crank or period of time compared to the inlet. This reduces the flow resistance. Often it is desirable that the intake period and the period of air supply had essentially the same length. The period of air supply preferably should be 90-110% of the period of intake. Since both of these period is limited to a maximum period during which the pressure in the crankcase is low enough, to allow maximum flow. Preferably provide maximum and uniform duration of the two periods. Thus, the position of the upper edge of the recess 10, 10’ will determine how early deepening "come in contact" with each respective vent window 9, 9’. Therefore, it is preferable that the recess 10, 10’ in the piston, which is joined with each corresponding directed to the output side vent window 9, 9’, locally at that window had the height in the axial direction, which is more than 1.5 times the height of the respective inlet ports, but preferably more than 2 times the height of the vent window. When this condition is fulfilled that the window has a normal height, so that the upper side of the piston when it is in its lower dead point races is alagaesia flush with the bottom side vent window or acts of one or two millimeters.

Preferably at the bottom of the recess is made of such form that the connection zone between the recess 10, 10 ' and the connecting hole 8, 8' was the maximum, because it reduces the flow resistance. This means that at the moment when the piston is in its top dead point, the recess 10, 10’ preferably is so far below that it does not overlap the connecting hole 8, 8’, as shown in figure 1. In General this means that the recess 10, 10’ in the piston, which is joined with each connecting hole 8, 8’, locally this hole has a height in the axial direction, which is more than 1.5 times the height of the respective connecting holes, but preferably more than 2 times the height of the connection holes.

The position fixing holes 8, 8’ relatively directed toward the exhaust inlet ports 9, 9’ in the axial direction can be changed significantly, provided that the holes and Windows are shifted from each other, i.e. in the direction tangent to the circumference of the cylinder, as shown in figure 1. Figure 1 illustrates the case where the connecting hole and the purge box 9, 9’ are overlapped in the axial direction, that is, the upper edge of each matched with the appropriate fixing holes located at the same height or above in the axial direction of the cylinder, than the lower edge of each of the respective inlet ports. One advantage is that in this type of structure is the hole and the window is largely aligned with each other, which reduces the flow resistance when the air flows from the connecting holes in the purge box. Consequently, more air can pass, which can lead to increased positive effects provided by the design, that is, reduced fuel consumption and lower emissions from the exhaust. In many two-stroke engines the upper side of the piston is on the same level with the lower edge of the exhaust hole and the lower edge of the inlet ports when the piston is in its bottom dead point. However, quite often the construction in which the piston acts as a millimeter or two above the bottom edge of the vent window. If the bottom edge of the vent window will be at an even lower altitude, between the connecting hole and the vent window will be created even greater overlap in the axial direction. When the air in the purge channel, the flow resistance decreases as due to the fact that the connecting hole and the vent window is largely aligned with each other and with ballshaped surface of the vent window.

Above stressed the importance of having an extended period of air supply to provide a low resistance to flow when switching between the cylinder and the piston. In addition, it was noted the advantage that the connecting hole is located at the same height or above in the axial direction of the cylinder than the lower edge of each of the respective inlet ports. When this condition is fulfilled, namely, that of the connecting hole/vent window shifted relative to each other along the periphery of the cylinder wall. Thus the transition from the hole 8 in the box 9 through the piston may occur in a direction slightly upward relative to the transverse direction of the cylinder. If, instead, the hole 8 would be located directly under the window 9, the transition would occur in the direction straight up. The result would be that the thread is first turned'd up and then, after reaching the vent window, would have changed its direction to the horizontal, that is consistently made two sharp turn. Due to the fact that the connecting hole and the vent window is shifted in the lateral direction from each other, allows the passage of the stream in the direction slightly upward with small turns.

As mentioned, provides bolshoyprospect, if aimed in the direction of release of the purge channels 3, 3’ will take place essentially in the transverse direction of the cylinder. In the passing direction slightly upward flow from the holes 8 in the box 9 will make a slight turn and then go straight in the transverse direction in the channel to move. Preferably the channel for movement takes place in the transverse direction of the cylinder to the place on the wall of the cylinder where there is a smooth rotation, so that the channel to move connects to the crankcase, where Carter has an inlet opening 20. Preferably each branch 11, 11’, leading to each respective connecting hole 8, 8’are located in such a way that it runs in the transverse direction of the cylinder or slightly up from this direction. Thereby indicate the preferred main direction of flow, which passes through the cylinder and the piston. In the shown embodiment, each branch passes at an angle from the bottom of the outer fixing holes 7, so that the branch has a first turn up after the external connecting hole, and then goes up and changes its direction on the cross, and takes place in the transverse direction to the connecting holes 8, 8’ in the wall 12 of the cylinder. Therefore, at the transition from the of alindra to the piston creates a zone of the flow passage in a direction slightly upward, after which the flow direction is preferably slightly changed to transverse the direction of flow in the channel for movement through which the stream runs right. Since the connecting hole 8 must be placed at a lower height than each corresponding purge box 9, this location is a natural. But you can also have one or two outer fixing holes above the intake channel 22-25. In this case, it preferably will be in a greater degree angle in the transverse direction of the cylinder than in the shown case. In this case, it can be located in such a way that each branch 11, 11’ will be essentially in the transverse direction of the cylinder to each of the corresponding connecting holes 8, 8’.

It seems that you can see the preferred flow upwards from the outer fixing holes 7 to the connecting hole 8 and further to purge the window 9 and the purge channel 3. In this case, it becomes obvious that the purge channel 3, passing to the inlet ports 9, takes place essentially in the direction tangentially relative to the cylinder, and the same is also largely true for the first part of the branches 11, passing from the connection holes 8. Thereby changing the direction of the with the of be small, when the air will pass from the branch 11 to the recess 10 of the piston and the purge channel 3.

1. Two-stroke engine (1) internal combustion engine with scavenging of crankcase having at least one cylinder (15) and at least one air channel located between the inlet (2) and the upper part of the at least two vent channels (3, 3’) directed toward the output side vent Windows (9, 9’)arranged close to the exhaust opening (19) of the cylinder, and at least one directed to the intake side vent window(14, 14’; 27, 27’), located close to the inlet (33) of the cylinder, and the flow in this window by using at least one vent channel(5, 5’; 28, 28’) or the like, and an air channel and air passages are so designed that the purge channels (3, 3’) can be filed and retained so much air that during the subsequent purging of them will not come out, essentially, nothing but air, wherein the air channel passes from the inlet (2)provided with a restrictive valve (4)and is managed by at least one parameter of the engine, for example, by controlling the throttle valve of the carburetor, and directed to the intake side cont the adjustment(s) window(s) (14, 14’; 27, 27’) is(s) so that it/they provide(s) the beginning of the purge air-fuel mixture (29) later than aimed in the output side vent window (9, 9’) begin blowing air.

2. The engine (1) internal combustion purge the crankcase according to claim 1, characterized in that each directed to the intake side vent window(14, 14’; 27, 27’) has an upper edge which is located below in the axial direction, that is, closer to the crankcase than the corresponding upper edge of the other of the inlet ports (9, 9’).

3. The engine (1) internal combustion purge the crankcase according to claim 1 or 2, characterized in that the upper part of each vent channel(5, 5’; 28, 28’) with directed into the intake side vent window(14, 14’; 27, 21’) connected to the air intake (2), but is of such design that it/they will be served is adapted amount of air that this number during the subsequent process of purging will end before the end of the air directed to the output side vent Windows (9, 9’)which is directed towards the inlet, vent window (s) provide(s) the beginning of the purge air-fuel mixture during the process of purging.

4. The engine (1) internal combustion purge the crankcase according to claim 1 or 2, Otley is audica fact, the inlet through at least one connecting channel (6, 6’) is connected, at least one connection opening (8, 8’) in the wall (12) of the engine cylinder, which is located in such a way that it is when the piston is at top dead center point connected with grooves (10, 10’)in the piston (13), and the data deepening lead to a number of vent channels (3, 3’) directed through the output side vent window (9, 9’).

5. The engine (1) internal combustion purge the crankcase according to claim 3 or 4, characterized in that the recesses (10, 10’) also lead to a number of vent channels(5, 5’; 28, 28’) through directed into the intake side vent window(14, 14’; 27, 27’).

6. The engine (1) internal combustion purge the crankcase according to claim 5, characterized in that when the piston is in its top dead point, the distance in axial direction between the upper edge of each of the recesses (10, 10’) in the piston, and the lower edge of each directed to the intake side vent window(14, 14’; 27, 27’) less than the corresponding distance for each directed to the output side vent window (9, 9’), so that each directed to the intake side vent window will communicate with the air intake (2) later when the piston moves upward in the direction of its top the th dead point.

7. The engine (1) internal combustion purge the crankcase according to any one of the preceding paragraphs, characterized in that at least one directed to the intake side vent window (27, 27’) with the purge channel (28, 28’) made in the form of deepening(27, 28, 27’, 28’) in the cylinder wall (15), with the deepening during the process of purging communicates with the hole (30, 30’) in the piston, so that the purge gases will pass by the piston through this the hole and the recess.

8. The engine (1) internal combustion purge the crankcase according to claim 7, characterized in that when the piston is in its top dead point, he covers all the deepening(27, 28, 27’, 28’), so that air cannot leak from the recess.

9. The engine (1) internal combustion purge the crankcase according to any one of the preceding paragraphs, characterized in that the connection opening (8, 8’) of the cylinder and each directed to the output side vent window (9, 9’) are shifted relative to each other along the periphery of the wall (12) of the cylinder, and directed to the output side vent Windows are essentially in the transverse direction of the cylinder from each inlet ports (9, 9’).

10. The engine (1) internal combustion purge the crankcase according to claim 9, wherein ka is the connecting branch (11, 11’), which leads to each respective connection opening (8, 8’), is directed in the transverse direction of the cylinder or slightly up from it.

11. The engine (1) internal combustion purge the crankcase according to any one of the preceding paragraphs, characterized in that the recess (10, 10’) in the piston, which is joined with the corresponding directed to the output side vent window (9, 9’), is located so that the air supply occurs during the period essentially equal to or greater duration, calculated as the angle of rotation of the crank or time period regarding intake.

12. The engine (1) internal combustion purge the crankcase according to any one of the preceding paragraphs, characterized in that period, the air supply is more than 90% of the period of intake, but less than 100% of the intake period.

13. The engine (1) internal combustion purge the crankcase according to any one of the preceding paragraphs, characterized in that the recess (10, 10’) in the piston, which is joined with the corresponding directed to the output side vent window (9, 9’), locally at that window has a height in the axial direction, which is more than 1.5 times the height of each vent window (9, 9’), preferably more than 2 times the height of the vent window.

14. Dr. who " (1) internal combustion purge the crankcase according to any one of the preceding paragraphs, characterized in that the upper edge of each of the connecting holes (8, 8’) is as high as the lower edge of each directed toward the issue, purge window (9, 9’), or higher than the lower edge of each sent to the output side vent window (9, 9’), in the axial direction of the cylinder.

15. The engine (1) internal combustion purge the crankcase according to claim 1 or 2, characterized in that at least one channel provided with a check valve, passes from the inlet (2) to the upper part of a number of vent channels (3, 3’).

16. The engine (1) internal combustion purge the crankcase according to claim 3 or 9, characterized in that at least one channel provided with a check valve, passes from the inlet (2) to the upper part, at least one vent channel (5, 5’) with directed into the intake side vent window (14, 14’), and this check valve is adapted to supply a more limited air flow in comparison with non-return valves belonging to purge channels located near the exhaust hole (19) of the cylinder.



 

Same patents:

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FIELD: mechanical engineering.

SUBSTANCE: invention relates to two stroke internal combustion crankcase compression engine designed for use in hand tools. According to invention, engine has at least one air channel between air intake and upper part, two scavenging channels with scavenging ports directed to side of discharge and located close to exhaust hole of cylinder. Engine has at least one scavenging port pointed to side of intake and located close of intake port of cylinder, delivery to said port being provided by at least one scavenging channel. Air channel and scavenging channels are of such design that such amount of air is fed and held in scavenging channels that nothing but air will get out during following scavenging process. Air intake from which air channel branches if provided with limiting valve controlled by at least one parameter of engine, for instance, under action of throttle valve of carburetor. Scavenging ports(s) pointed to side of intake is (are) arranged to provide beginning of delivering of air-fuel mixture later than scavenging with air through scavenging ports pointed to side of exhaust.

EFFECT: reduced consumption of fuel and discharge of noncombusted fuel with exhaust gases.

16 cl, 5 dwg

FIELD: engines and pumps.

SUBSTANCE: two-cycle engine with layer-by-layer blowdown includes piston, cylinder containing a piston with possibility of its back-and-forth movement, crankshaft that is connected to the piston by means of a piston-rod; casing containing the crankshaft with possibility of its rotation, gas mixture channel that supplies the gas mixture to the casing, blowdown channel that is continued between inlet blowdown opening that opens to the casing and blowdown opening that opens to cylinder and air channel that is connected to blowdown channel in intermediate position for supply of the air to blowdown channel. On some part of upward piston stroke, during which the piston moves towards the opposite side in relation to casing, the latter is connected to blowdown channel through blowdown opening; at that, negative pressure is created in the casing. Resistance to the flow from intermediate position of the blowdown channel where the air channel is connected to blowdown opening is lower than resistance to the flow from intermediate position, where air channel is connected to inlet blowdown opening. Versions of two-cycle engine design with layer-by-layer blowdown are described.

EFFECT: large amount of the air introduced to blowdown channel from air channel flows to blowdown opening and can enter the cylinder without changing the flow direction.

20 cl, 7 dwg

FIELD: mechanical engineering.

SUBSTANCE: invention relates to two stroke internal combustion crankcase compression engine designed for use in hand tools. According to invention, engine has at least one air channel between air intake and upper part, two scavenging channels with scavenging ports directed to side of discharge and located close to exhaust hole of cylinder. Engine has at least one scavenging port pointed to side of intake and located close of intake port of cylinder, delivery to said port being provided by at least one scavenging channel. Air channel and scavenging channels are of such design that such amount of air is fed and held in scavenging channels that nothing but air will get out during following scavenging process. Air intake from which air channel branches if provided with limiting valve controlled by at least one parameter of engine, for instance, under action of throttle valve of carburetor. Scavenging ports(s) pointed to side of intake is (are) arranged to provide beginning of delivering of air-fuel mixture later than scavenging with air through scavenging ports pointed to side of exhaust.

EFFECT: reduced consumption of fuel and discharge of noncombusted fuel with exhaust gases.

16 cl, 5 dwg

FIELD: mechanical engineering; internal combustion engines.

SUBSTANCE: according to invention, engine includes at least two groups of cylinders. Each group contains one or several cylinders in which working processes are synchronous. Working processes in separate groups of cylinders process through equal angular spaces. In process of operation of engine, fuel-air mixture is sucked into crankcase by each group of cylinders separately, is partially compressed and bypassed into combustion chamber of other group of cylinders in which scavenging of cylinders occurs at this moment.

EFFECT: improved performance characteristics of two-stroke internal combustion engine with crankcase displacement scavenging owing to improvement of gas exchange process.

1 dwg

FIELD: mechanical engineering.

SUBSTANCE: invention relates to two stroke internal combustion crankcase compression engine designed for use in hand tools. According to invention, engine has at least one air channel between air intake and upper part, two scavenging channels with scavenging ports directed to side of discharge and located close to exhaust hole of cylinder. Engine has at least one scavenging port pointed to side of intake and located close of intake port of cylinder, delivery to said port being provided by at least one scavenging channel. Air channel and scavenging channels are of such design that such amount of air is fed and held in scavenging channels that nothing but air will get out during following scavenging process. Air intake from which air channel branches if provided with limiting valve controlled by at least one parameter of engine, for instance, under action of throttle valve of carburetor. Scavenging ports(s) pointed to side of intake is (are) arranged to provide beginning of delivering of air-fuel mixture later than scavenging with air through scavenging ports pointed to side of exhaust.

EFFECT: reduced consumption of fuel and discharge of noncombusted fuel with exhaust gases.

16 cl, 5 dwg

FIELD: machine building.

SUBSTANCE: invention refers to bearing unit of crankshaft of internal combustion engine. The bearing unit consists of bearing (10) mounted on crankshaft (16) of the internal combustion engine, of seat (11, 15) of the bearing designed for placement of bearing (10) and of system (20) of packing designed for sealing relative to crankshaft (16) and seat (11, 15) of the bearing. At least one part of seat (11) of the bearing has a reinforcing element (12) positioned in the seat of the bearing. Also, surface (13) of at least one part of seat (11) of the bearing adjoining bearing (10) is made out of plastic. There are also claimed the internal combustion engine comprising the said bearing unit and a hand tool with a mechanical drive containing the said internal combustion engine.

EFFECT: improved bearing unit of crankshaft due to bearing unit sealing and optimal installation of bearing and/or bushing of bearing in seat of bearing with decreased allowances, which prevents bearing and/or bushing of bearing rotation in bearing seat; minimised hazard of bearing distortion and bearing and/or bushing of bearing compression in bearing seat under force causing finite destruction of bearing and/or bushing of bearing.

13 cl, 4 dwg

FIELD: engines and pumps.

SUBSTANCE: invention relates to hand-held devices driven by ICE. Proposed device comprises housing of engine (200) and ICE (202) with cylinder (204) and crankshaft. It incorporates fan wheel (214) driven by crankshaft to run about axle A. Fan casing (216) surrounds fan wheel (214) to interact therewith. Inlet (224) for air to be combusted is arranged radially outside fan wheel (214) to direct air to ICE (202) and has inlet (226) and channel (228). Inlet (226) has first edge (230) radially abutting on has wheel (214) outer periphery (220). Angle X between first line L1 extending radially from axle A parallel with the main direction of cylinder (204) and radius L2 extending radially from axle A so that to cross said first edge (230), is smaller than 70 degrees, preferably, smaller than 66 degrees and, more preferably, than 62 degrees. Invention covers the versions of hand-held device.

EFFECT: decreased weight.

20 cl, 6 dwg

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