Internal combustion engine

Abstract

The invention discloses a valve mechanism of an internal combustion engine. The timing device comprises a timing gear, a valve guide pipe, a valve seat and a valve, and further comprises a transmission shaft, a support, a locking device installed on the support and a connecting part for connecting the support and the valve, wherein the transmission shaft is distributed on a shaft body and provided with a disc-shaped object A and a disc-shaped object B which have specific phases and correspond to the valve. Opening and closing of an air valve are achieved through relative movement between a groove in a disc-shaped object A on a transmission shaft and a protrusion on a support and / or a connection part, and sealing after the air valve is closed is achieved through cooperation and interaction of a fan-shaped arc end face of a disc-shaped object B on the transmission shaft and a locking device. The valve spring directly acting on the valve does not exist in the valve mechanism of the internal combustion engine, the phenomenon that when the valve mechanism of the internal combustion engine operates at a high speed, the valve is not closed and is opened by the cam rotating at a high speed is avoided, and the resonance phenomenon generated by the valve spring and the energy loss caused by the valve spring are avoided.

Description

2. Technical field:

[0001] The present invention relates to an internal combustion engine, and in particular to a valve train of the internal combustion engine. 3. Background technology:

[0002] At present, the valve train of a four-stroke internal combustion engine is composed of a valve train group and a valve group. The valve train group is all the parts from the timing gear to the valve action. Its composition varies depending on the form of the valve train. Its function is to drive the valve to open and close at a fixed time. The composition of the valve group has basically nothing to do with the form of the valve train. When this valve train is working, the valve exists in three states: valve opening process, valve closing process, and valve keeping closed process; the valve opening process is to drive the valve to open directly or indirectly through the rotation of the cam on the camshaft, and compress the valve spring at the same time; the valve closing process is that the valve is driven to close under the tension of the valve spring; the valve keeping closed process is that the valve is kept closed under the pre-tension of the valve spring. Since the forces for opening and closing the valve come from the cam and the valve spring respectively, and the directions of the forces acting on the valve are opposite, it is difficult to achieve perfect coordination when the forces are switched. Usually, when the speed of the internal combustion engine reaches a certain high, the valve is opened by the high-speed rotating cam before it is completely closed, causing the valve to separate from the cam; in addition, when the operating frequency of the valve spring is equal to or an integer multiple of the natural vibration frequency, the valve spring will resonate, and the valve timing will be destroyed during resonance, and the valve will rebound and impact. In addition, since the tension of the valve spring needs to be overcome to open the valve, the valve spring will produce a certain amount of energy loss.

[0003] IV. Purpose of the invention:

[0004] The purpose of the present invention is to overcome the defects of the existing internal combustion engine valve mechanism. By improving the valve transmission method of the internal combustion engine valve mechanism, the two processes of valve opening and valve closing are combined into one process of valve opening and closing, so as to achieve smooth conversion of the direction of the force acting on the valve, eliminate the phenomenon of separation of the mechanism contact parts, eliminate the resonance of the valve spring, and eliminate the energy loss caused by the valve spring.

[0005] V. Technical solution:

[0006] The valve train of an internal combustion engine of the present invention comprises a timing gear, a valve, a valve guide, and a valve seat, and is characterized in that: it also comprises a transmission shaft, a disc A and a disc B distributed on an axis body and having a specific phase corresponding to the valve, a bracket, a locking device installed on the bracket, and a connecting portion connecting the bracket and the valve; the axial projection of the disc A is an irregular sector, the center angle of which is η, 115°≤η≤145°, and a groove is provided on the disc surface; the axial projection of the disc B is a sector, and the corresponding center angle is β; the η angle bisector and the β angle bisector are The angle of the axial projection is equal to 180 degrees, and the sum of η and β is equal to 360 degrees; one end of the connecting portion is connected to the bracket, and the other end is connected to at least one of the valves, and the bracket and / or the connecting portion have an axial protrusion; the radial projection of the transmission shaft axis intersects perpendicularly with the radial projection of the center line of the bracket, the connecting portion, and the valve; when the transmission shaft rotates, the protrusion moves relatively in the groove in some phases, and the fit is a clearance fit, and in other phases, the fan-shaped arc end face of the disk B cooperates and interacts with the locking device.

[0007] 6. Beneficial effects:

[0008] The structural feature of the present invention is that the relative movement between the groove on the disk A on the transmission shaft and the axial protrusion on the bracket and / or the connecting part is used in the valve mechanism to drive the driven part composed of the bracket, the connecting part and the valve to move up and down, so as to realize the process from opening to closing of the valve, and the fan-shaped arc end face of the disk B cooperates and interacts with the locking device to realize the sealing after the valve is closed; the two are combined to simplify the valve opening process, closing process and valve keeping closed state process of the existing internal combustion engine valve mechanism into two parts: the valve "opening and closing" process and the "valve keeping closed state" process. In particular, the present invention realizes the smooth conversion of the direction of the force in the valve opening and closing process. The entire device removes the valve spring directly acting on the valve, so that the valve is effectively controlled during the working process, solves the problem of contact parts detaching when the existing internal combustion engine valve mechanism works at high speed, eliminates the valve spring resonance phenomenon and the energy loss caused by the valve spring.

[0009] 1: Energy consumption of valve spring:.

[0010] Known conditions: Complete combustion of 1kg of gasoline can release 46000kj of heat.

[0011] Assumptions: A conventional four-cylinder gasoline engine with four valves in each cylinder runs at 2,000 rpm, with a force of 600N for each valve to open and a valve stroke of 10mm for one hour.

[0012] Valve spring energy consumption: = 1 hour * valve working times per minute * number of valves * valve opening force * stroke

[0013] Q (actual valve spring energy consumption) = 60*2000 / 2*16*600*0.01 = 5760 (kj);

[0014] 1L (93# gasoline) = 0.737kg;

[0015] Q(1L-93# gasoline)=46000*0.737=33902(kj)

[0016] Q(actual valve spring fuel consumption) = Q(actual valve energy consumption) / Q(1L-93# gasoline)

[0017] Q (actual valve spring fuel consumption) = 5760 / 33902 = 0.170 (L) = 170 (ml);

[0018] 2: The influence of resonance on the valve mechanism:

[0019] Due to the existence of valve springs in the existing internal combustion engine valve train, the entire valve train constitutes an elastic system. The operating frequency of the valve spring overlaps with its natural frequency to produce resonance, causing valve rebound impact and affecting the normal operation of the internal combustion engine.

[0020] 3: The impact of high speed on the valve mechanism:

[0021] a: Assume that the speed of an internal combustion engine is 8000 rpm;

[0022] b: Assume that the time it takes for the valve spring to close the valve is 0.02 seconds;

[0023] Because the camshaft speed is half of the crankshaft speed, 8000 / 2 / 60=200 / 3 (rev / second), the time for the camshaft to rotate one circle is 3 / 200 seconds. If the time required for the valve to close under the action of the valve spring tension is greater than 15 thousandths of a second, the valve will not close tightly, and the intake and exhaust valves may even be open, disrupting the normal working cycle of the internal combustion engine.

[0024] VII. Illustrations:

[0025] Figure 1 Schematic diagram of the principle of the present invention;

[0026] Figure 2 Parts diagram of an embodiment of the present invention;

[0027] Figure 3 An exploded view of the active part of an embodiment of the present invention;

[0028] Figure 4 An exploded view of a driven part of an embodiment of the present invention;

[0029] Figure 5 An assembly diagram of an embodiment of the present invention;

[0030] Figure 6 An exploded view of an embodiment of the present invention;

[0031] Figure 7 Other forms of the present invention 1 Exploded view;

[0032] Figure 8 Other forms of the present invention 2 Exploded view;

[0033] Fig. 9 Other forms of the present invention 3 explosion view;

[0034] Fig.10 A schematic diagram of the thrust profile of the valve train of the present invention;

[0035] Fig.11 Schematic diagram of the pressure angle of the valve train of the present invention.

[0036] In the figure, 1 is the timing gear, 2 is the transmission shaft body, 2-1 is the irregular sector disk (disc A), 2-2 is the sector disk (disc B), 2-1-1 is the groove on the irregular sector disk, 2-2-1 is the arc end face of the sector disk, 3 is the connecting part, 3-1 is the lifting ear on the connecting part, 4 is the bracket, 4-1 is the axial holes at the two transverse ends of the bracket, 4-2 is the axial cylindrical protrusion (roller) on the bracket, 5 is the valve, 6 is the key, 7 is the transmission shaft head nut, 8 is the pin, 9 is the small pin, 10 is the valve guide, 11 is the valve seat, 12 is the locking device = positioning bead, η is the center angle corresponding to the theoretical outline of the groove, η = ∠COD, β is the center angle of the sector disk, β = ∠EOF, A is the disc A, B is the disc B, and CD is the theoretical outline of the groove.

[0037] 8. Best Practice:

[0038] In order to reduce the mass of the driven part of the valve mechanism of the internal combustion engine and reduce its kinetic inertia, this embodiment adopts a scheme in which the groove on the drive shaft disk A drives the driven part, so that the mass of the driven part is relatively reduced; in order to further simplify the structure, the disk A and the disk B are combined into a "remaining circular disk", so that the entire valve mechanism is more concise.

[0039] like Figure 1 , Figure 2 , Figure 3 , Figure 4 As shown: the active part of the valve train of the internal combustion engine includes a timing gear 1 and a transmission shaft 2, and the driven part includes a connecting part 3, a bracket 4, a valve 5, and a locking device 12. The valve guide 10 and the valve seat 11 are installed on the cylinder head in a static fit manner.

[0040] Timing gear: In this embodiment, the timing gear 1 has no essential difference from the timing gear used in existing internal combustion engines.

[0041] Drive shaft: Figure 2 , Figure 3 As shown: In this embodiment, the drive shaft 2 is provided with pairs of incomplete circular disks with specific phases and grooves 2-1-1 that are opposite and mirror images of each other. Each pair of disks corresponds to the valves one by one, and the spacing between the disks is equal to the thickness of the connecting portion 3. In other words: the phases of each pair of incomplete circular disks are arranged on the drive shaft 2 according to the ignition sequence, each pair of incomplete circular disks corresponds to the valves of each cylinder one by one, and the grooves of each pair of incomplete circular disks are opposite and mirror images of each other; the incomplete circular disk is composed of an irregular sector and a sector, and there is a groove 2-1-1 on the irregular sector disk surface, and the width of the groove 2-1-1 is equal to the diameter of the axial cylindrical protrusion 4-2 on the downward probe steel plate on the bracket 4, as shown in FIG. Figure 1 , Figure 2 As shown: the theoretical groove profile CD is a smooth curve, and the central angle corresponding to the theoretical groove profile CD is η, η = ∠COD; the central angle of the other part of the sector is β, β = ∠EOF; η + β = 360°, 115° ≤ η ≤ 145°.

[0042] Connection: Figure 4 As shown: In this embodiment, the connecting portion 3 is long and has a U-shaped groove in the upper half. The reason why the connecting portion 3 is made into a U-shaped groove in this embodiment is to facilitate the processing and manufacturing of parts. A rectangular open groove is also possible, or an asymmetric structure such as an open groove is not used. The width of the groove is equal to the diameter of the corresponding transmission shaft journal. There is a lifting ear 3-1 at the top of the groove, and there is a vertical circular hole at the bottom of the connecting portion 3. The diameter of the hole is equal to the diameter of the valve stem.

[0043] Bracket: As Figure 4 As shown: In this embodiment, the bracket 4 is viewed from above in the shape of an "I" character, and holes 4-1 are axially opened at the two horizontal ends of the "I" character, and the diameter of the hole is equal to the diameter of the ear 3-1 at the top of the "U"-shaped groove of the connecting part 3. There is a preset vertical hole for installing the locking device 12 in the middle position of the two horizontal parts of the "I" shape, and a steel plate is inserted down at the "vertical" position of the "I"-shaped bracket 4. The thickness of the steel plate is equal to the thickness of the connecting part 3, and there is an axial protrusion 4-2 at the bottom end of the steel plate, and the protrusion 4-2 is cylindrical.

[0044] Locking device: The locking device 12 adopts a positioning bead.

[0045] This embodiment is connected in the following manner: Figure 3 , Figure 5 As shown: the timing gear 1 is connected to the transmission shaft 2 through a key 6, a keyway and a shaft head lock nut 7; Figure 5, Figure 6 As shown in the figure: The journal of the drive shaft corresponding to the "U"-shaped groove of the connecting part 3 passes through the "U"-shaped groove, and is placed between two mirror-image incomplete circular disks. The fit between the journal of the drive shaft and the "U"-shaped groove, and between the connecting part 3 and the incomplete circular disk is a clearance fit; the lifting lug 3-1 at the top of the "U"-shaped groove is fitted with the hole 4-1 on the bracket 4, and is fixedly connected by a pin 8 in a press fit manner. The downward-probing steel plate on the bracket 4 is placed inside the "U"-shaped groove opening of the connecting part 3; the hole at the bottom of the connecting part 3 is fitted with the valve stem, and the valve stem is fixed by a pin 9; the positioning bead 12 is installed in the reserved installation hole on the "I"-shaped bracket 4 in a press fit manner.

[0046] When the timing gear 1 drives the drive shaft 2 to rotate, when the arc end face 2-2-1 of the fan-shaped part of the incomplete circular disk cooperates with and interacts with the positioning bead 12 installed on the bracket 4, the valve 5 is in the closed state. Since the distance from the lowest point of the positioning bead 12 to the axis of the drive shaft is less than the radius of the fan-shaped part of the incomplete circular disk, the positioning bead 12 is squeezed by the arc end face 2-2-1 of the fan-shaped part, generating a force in the opposite direction to the opening direction of the valve 5. The opposite force causes the bracket 4, the connecting part 3, and the valve 5 to have a movement trend in the opposite direction to the opening direction of the valve 5, making the valve 5 closely fit with the valve seat 11, realizing the sealing after the valve 5 is closed. At this time, the rotation angle of the drive shaft 2 is β, and the valve 5 is in the closed state within this rotation angle; when the arc end face 2-2-1 of the fan-shaped part of the incomplete circular disk separates from the positioning bead 12 installed on the bracket 4, the axial cylindrical protrusion 4-2 on the steel plate where the bracket 4 probes downward into the "U"-shaped groove opening of the connecting part 3 enters the groove 2-1-1 on the incomplete circular disk. The protrusion 4-2 moves in the groove 2-1-1, and the fit between the two is a clearance fit. Since the valve 5 is restricted by the valve guide 10, the valve 5, the connecting part 3, and the bracket 4 can only move along the center line of the valve guide 10. Since the difference between the distance from the point on the theoretical profile CD of the groove to the axis of the drive shaft and the rotation radius OC changes from small to large and then from large to small, when the drive shaft 2 continues to rotate, the valve 5 gradually opens from the closed state to the maximum lift, and then from the maximum lift to the closed state, completing the opening and closing process of the valve 5. At this time, the rotation angle of the drive shaft 2 is η. Since η + β = 360°, as the drive shaft 2 rotates, it enters the next cycle and repeats continuously. [Student: Ф (推程运动角) = η / 2Ф (回程运动角) = η / 2Ф S(近休止角) = β η + β = 360°]

[0047] In the above internal combustion engine valve train, the protrusion that interacts with the groove can be set not only on the bracket, but also on the connecting part, or at the common position of the bracket and the connecting part.

[0048] In the above-mentioned embodiments, the valve mechanism of the internal combustion engine is connected to one valve by a connecting portion, and it can also be connected to two or more valves of the same type in the same cylinder through a connecting rod or other means.

[0049] In the above-mentioned embodiment, the locking device of the valve mechanism of the internal combustion engine adopts a positioning bead. When the positioning bead is squeezed by the arc end face of the fan-shaped disk, the spring inside the positioning bead is compressed, so that the spring tension generated by it causes the valve to remain in a closed state; the locking device can also be a steel leaf spring or other elastic material installed on the bracket, as long as it is squeezed by the arc end face of the fan-shaped disk, the bracket, connecting part, and valve will produce a movement trend opposite to the valve opening direction, and the valve and the valve seat can fit tightly.

[0050] The valve mechanism of the internal combustion engine of the present invention realizes light load operation during operation, so the material can be 40Cr, surface quenched to 56-60HRC, or 38CrMoA1, nitrided to 60-67HRC. In this embodiment, materials such as 20Cr, 20CrMn, etc., which are surface quenched to a hardness of 55-60HRC, should also be suitable.

[0051] In the above embodiment, the disk A and the disk B on the shaft of the transmission shaft are combined to form a residual circular disk. Its structural feature is that the two residual circular disks with grooves on the sides are mirror images of each other, the grooves are opposite, and the connecting part is placed in the middle of the two residual circular disks; of course, the implementation method can also adopt other layout arrangements, such as Figure 7 As shown: two incomplete circular disks with grooves on one side are mirrored to each other, and then merged back to back into one after mirroring. The grooves are on both sides of the disk surface to form a new "incomplete circular disk", and the incomplete circular disk is placed in the groove of the connecting part.

[0052] The disk A and disk B can also be arranged separately, and the combinations are as follows: Figure 8 As shown in the figure: one is that two disc-shaped objects A with grooves on one side are mirror images of each other, and then they are merged back to back into one. The grooves are on both sides of the disc surface to form a new disc-shaped object A. The disc-shaped object A is placed in the groove of the connecting part, and the two disc-shaped objects B are placed on both sides of the connecting part respectively; the other is as shown in the figure. Fig. 9 As shown: two disk-shaped objects A with grooves on one side are mirror images of each other, the grooves are opposite to each other, the connecting part is placed in the middle of the two disk-shaped objects A, and a single disk-shaped object B is placed in the groove of the connecting part; another type is that two disk-shaped objects A with grooves on one side are mirror images of each other, the grooves are opposite to each other, and are placed on both sides of the connecting part, and two disk-shaped objects B are also placed on both sides of the connecting part.

[0053] The above embodiment and the internal combustion engine valve mechanism described later all adopt a double groove structure for each unit, in order to make the whole mechanism run more stably. In fact, each unit can also adopt a single groove structure, which is simpler! But the stability is not as good as the double groove structure.

[0054] The internal combustion engine valve mechanism of the present invention belongs to the category of cam mechanism. In the present invention, the camshaft is called a transmission shaft in order to distinguish it from the camshaft in the existing internal combustion engine valve mechanism. In addition, the method of maintaining high-pair contact in the existing internal combustion engine valve mechanism (valve opening and closing) is achieved by force locking, and the force for opening and closing the valve comes from the cam and the valve spring. The method of maintaining high-pair contact in the internal combustion engine valve mechanism (valve opening and closing) of the present invention is completed by form locking, and the force on the valve comes from the groove on the irregular sector disk; when the valve of the existing internal combustion engine valve mechanism is in a closed state, the sealing of the valve is affected by the pre-tensioning force of the valve spring, while the present invention is achieved by the cooperation and interaction between the arc end face of the sector disk and the locking device, which is similar to the force-locking type disc cam mechanism.

[0055] Regarding the selection of the motion law of the follower in the valve mechanism of an internal combustion engine, the motion law of the valve in the existing valve mechanism of an internal combustion engine generally adopts the fifth-order polynomial motion law (the profile of the cam determines the valve motion law), and the characteristic of the fifth-order polynomial motion law is that it is "suitable for high speed and medium load". The valve mechanism of the internal combustion engine of the present invention does not have a valve spring directly acting on the valve, thereby realizing light load operation. The valve motion law can select the "sinusoidal acceleration motion law", and the characteristic of the sinusoidal acceleration motion law is that it is "suitable for high speed and light load". By changing the valve motion law, the cam profile is improved, thereby improving the ventilation efficiency of the internal combustion engine.

[0056] The extrapolated profile equation is:

[0057] Use the inversion method to establish a coordinate system and find the coordinates of the high-pair contact point; as shown in Figure 10:

[0058] Base circle radius r b ; offset distance e; B0 is the starting point of the push stroke; B is the arbitrary contact point of the high pair (roller center); O is the rotation center; S is the displacement of the follower; the roller radius is r r ; tanθ is the slope of the normal line at point B; h is the stroke.

[0059] BB'=S A'B'=S0A'B=S0-S

[0060]

[0061]

[0062] The coordinates of point B are the coordinates of the roller center:

[0063] The actual profile equation of the groove wall is:

[0064]

[0065]

[0066] Pressure angle: As shown in Figure 11:

[0067] lop=V / ω(point p is the relative instantaneous center) tanα=(e+lop) / (S0-S)

[0068] Because: S0 2 +e 2 =r b 2 So: tanα=(e+lop) / [(r b 2 -e 2 ) 1 / 2 -S]

[0069] Base circle radius;

[0070]

[0071] α<[α](allowable pressure angle)pressure angle range(25°-35°)

[0072]

[0073] S needs to satisfy the law of sinusoidal acceleration motion;

[0074] Right now:

[0075]

[0076]

[0077] Or S satisfies the law of motion of a quintic polynomial;

[0078] Right now:

[0079]

[0080]

[0081] A buffer section needs to be set at the connection between the near rest and the push stroke, and the connection between the return stroke and the near rest. A smooth transition needs to be ensured at the connection between the push stroke and the return stroke. The Camtra plug-in in the SolidWorks software is used to generate the cam.

Claims

1. A valve train for an internal combustion engine comprising a timing gear, a valve, a valve guide, and a valve seat, characterized in that: It also includes a transmission shaft, a bracket, a locking device installed on the bracket, and a connecting part connecting the bracket and the valve, with a disk A and a disk B distributed on the shaft body with specific phases corresponding to the valves; the axial projection of the disk A is an irregular sector with a center angle of η, and a groove is provided on the disk surface; the axial projection of the disk B is a sector with a corresponding center angle of β; the angle between the η angle bisector and the β angle bisector axial projection is equal to 180 degrees, and the sum of η and β is equal to 360 degrees; one end of the connecting part is connected to the bracket, and the other end is connected to at least one of the valves, and the bracket and / or the connecting part have an axial protrusion; the radial projection of the axis of the transmission shaft intersects perpendicularly with the radial projection of the center line of the bracket, the connecting part, and the valve; when the transmission shaft rotates, the protrusion moves relatively in the groove in some phases, and the fit is a clearance fit, and in other phases, the sector arc end face of the disk B cooperates and interacts with the locking device.

2. The valve train of an internal combustion engine according to claim 1, characterized in that: 115°≤η≤145°.

3. The valve train of an internal combustion engine according to claim 1, characterized in that: The theoretical profile of the groove is a smooth curve.

4. The valve train of an internal combustion engine according to claim 1, characterized in that: The contact point between the locking device and the arc end surface of the sector disk of the disk-shaped object B is a pointed bottom, a flat bottom, a curved bottom or a roller.

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