WO2006119698A1

WO2006119698A1 - Intake cam and exhaust cam of camshaft of internal combustion engine

Info

Publication number: WO2006119698A1
Application number: PCT/CN2006/000912
Authority: WO
Inventors: Jiaquan Yan
Original assignee: Jiaquan Yan
Priority date: 2005-05-13
Filing date: 2006-05-08
Publication date: 2006-11-16
Also published as: CN1861989A

Abstract

An intake cam and exhaust cam of camshaft of internal combustion engine are disclosed, wherein the cam profile includes a base circle segment, a vale-opening buffer segment, a working segment and a valve-closing buffer segment; in the cold situation, the ending point of the valve-opening buffer segment is located before the point where the valve clearance is eliminated; and in the cold situation, the beginning point of the valve-closing buffer segment is located after the point where the valve clearance begins to occur .

Description

Inlet and exhaust cams on the camshaft of internal combustion engines

The present invention relates to an intake and exhaust cam on a camshaft of an internal combustion engine, the cam profile of which includes a base circle, a valve opening buffer section, a working section and a valve closing buffer section. Background technique

The internal combustion engine works by burning fuel in the cylinder to work, thereby outputting power to the outside. In the case of a certain displacement of the internal combustion engine, if you want to increase the power output, the effective way is to provide more fuel and make it fully and effectively burned. However, it is easy to provide more fuel in the cylinder, but it is necessary to provide More air makes it harder to burn the fuel. The crankshaft speed of the internal combustion engine is very high. The stroke of each piston is very short. For example, the engine of Shanghai Santana sedan has a speed of 5600r/min at maximum power and a travel time of only 0.0054s, so that the short intake and exhaust time is The charging efficiency and exhaust efficiency of the internal combustion engine have high requirements. To this end, efforts have been made to improve the laws and countermeasures for improving the charging efficiency and the exhaust efficiency to improve the performance of the internal combustion engine. However, since the cam profile design of the conventional internal combustion engine camshaft has the following problems, that is, the end point of the valve opening buffer section is set after the elimination of the valve clearance point, and the start point of the valve closing buffer section is set before the start of the valve clearance point, the cam profile The design technique reduces the fullness factor of the cam profile, which affects the charging efficiency and exhaust efficiency, and reduces the power of the internal combustion engine. The camshaft cam contour map in the tenth "gas distribution phase" of the "Liberation CA1091 Truck Map" published by Liaoning Science and Technology Press shows that the end of the valve opening buffer section of the cam profile is located after the valve clearance point is eliminated. And the starting point of the valve closing buffer section is before the start of the valve clearance point. Summary of the invention

SUMMARY OF THE INVENTION The technical problem to be solved by the present invention is to provide an intake and exhaust cam capable of improving the fullness coefficient of a cam profile, thereby improving the gassing efficiency and exhaust efficiency of the internal combustion engine.

In order to solve the above problem, the contours of the intake and exhaust cams on the camshaft of the internal combustion engine of the present invention include a base circle, a valve opening buffer section, a working section and a valve closing buffer section. In the cold state, the end point of the valve opening buffer section is set at Before the valve clearance point is eliminated, and the starting point of the valve closing buffer section is set after the valve clearance point begins to appear.

Depending on the direction of travel of the cam, starting from the cam base circle, the invention first arrived is referred to as "front" or "start", and the latter invention is referred to as "post" or "final".

Since the internal combustion engine has a valve clearance to compensate for the amount of expansion of the valve and its transmission after being heated,

- 1 - Confirmation In the design of the cam profile of 2006/000912, before the working section, a buffer section slightly larger than the maximum valve clearance is arranged to avoid excessive impact load on the valve. After passing through the buffer section, the working section then accelerates the valve lifter and the transmission mechanism, and the valve is quickly slammed. On the same principle, after the working section, a buffer section slightly larger than the maximum valve clearance is arranged for the valve to be closed. A valve clearance begins to appear. The valve clearance is the clearance reserved during cold assembly. The design of the buffer section in the conventional cam profile is also based on the elimination of the valve clearance in the cold state. However, the normal operation of the internal combustion engine is performed in the hot state. In the hot state, the valve and its transmission mechanism are thermally expanded, which inevitably causes the valve clearance to further shrink. Therefore, in the running heat state of the internal combustion engine, the elimination of the valve clearance point follows the reduction of the valve clearance and moves forward, and the same principle begins to appear. The clearance point also moves backwards following the reduction of the valve clearance. The internal combustion engine is obviously used for work. Therefore, when designing the intake and exhaust cams, it should be based on the working state. However, since it is difficult to determine the value of the valve clearance in the working state, the present invention is designed when designing the cam profile. Referring to the value of the valve clearance in the cold state, by setting the end point of the valve opening buffer section to the cold state, a certain cam angle before the valve clearance point is eliminated to compensate for the thermal expansion of the valve and its transmission mechanism due to the hot state. Actually eliminate the cam angle of the forward movement of the valve clearance point, and a certain cam angle after the start of the valve clearance point by setting the starting point of the valve closing buffer section to the cold state, to compensate for the thermal expansion of the valve and its transmission mechanism due to the hot state. As a result, the cam angle of the valve clearance point is actually started to occur, which occurs in the cold state, and the end point of the valve opening buffer section is located before the valve clearance point is eliminated and the starting point of the valve closing buffer section is located after the valve clearance point begins to appear. phenomenon. Due to the large number of internal combustion engine models, the structure, displacement and valve clearance are different, so the end point of the valve opening buffer section starts to cancel the valve clearance point in the cold state and the starting point of the valve closing buffer section starts to the cold state. The amplitude of the cam angle that moves after the occurrence of the valve clearance point should vary from model to model. The end point of the valve opening buffer section moves to the cold state to eliminate the valve clearance point before moving the one-degree cam angle or the valve closing buffer section to the cold state, and then the valve clearance point starts to move after the first cam angle, which is equivalent to extending the working section by one degree. The cam angle, and each extended cam angle of the working section, can improve the fullness coefficient of the corresponding cam profile, increase the time of the valve opening, and increase the charging efficiency and exhaust efficiency, thereby improving the power output of the internal combustion engine.

For a vehicle internal combustion engine with a displacement of 0.07I^6.5L, the valve clearance is between 0.05mm and 0.4mm. In the cold state, the end point of the valve opening buffer in the inlet and exhaust cam profiles is set to a cold state. The optimum range before the clearance of the valve clearance point is between 2° and 9° cam angle. · The same principle, the starting point of the valve closing buffer section in the intake and exhaust cam profiles is set after the valve clearance point starts to appear in the cold state. The optimum range is between 2° and 9° cam angles.

As a preferred configuration of the present invention, the valve opening buffer section is composed of an acceleration section and an equal speed section, and the valve closing buffer section is composed of an equal speed section and a deceleration section for mitigating an impact load on the valve. DRAWINGS

The invention will now be described in further detail with reference to the drawings and embodiments.

Figure 1 is a schematic view of the contours of the intake and exhaust cams on the camshaft of the existing internal combustion engine.

2 is a schematic view showing the contours of the intake and exhaust cams on the camshaft of the internal combustion engine of the present invention.

Figure 3 is a graph showing the speed and lift variation of the valve opening buffer section in the cam profile shown in Figure 2. detailed description

Figure 1 shows a schematic diagram of the contours of the intake and exhaust cams on the camshaft of the existing internal combustion engine. The figure is taken from the tenth "gas phase" of the "Liberation CA1091 Truck Map" published by Liaoning Science and Technology Press. Camshaft cam profile. In the figure, 1 is the cam, point 9 is the cam axis, point 7 is to eliminate the valve clearance, point 8 is to start the valve clearance, point 4 is the maximum valve lift, point 6·-point 1 is the cam base circle 10, point 2 - Point 3 is the valve opening buffer section 11, point 3 - point 4 to point 5 is the working section 12, and point 5 - point 6 is the valve closing buffer section 13. The figure shows that the end point 3 of its valve opening buffer section 11 is after the valve clearance point 7 is eliminated in the cold state, and the starting point 5 of the valve closing buffer section 13 is in the cold state before the valve clearance point 8 begins to appear.

2 is a schematic view showing the contours of the intake and exhaust cams on the camshaft of the internal combustion engine of the present invention, which differs from the cam profile of FIG. 1 only in that the end point 3 of the valve opening buffer section 11 is in the cold state before the valve clearance point 7 is eliminated. And the start point 5 of the valve closing buffer section 13 is located after the valve clearance point 8 starts to appear in the cold state. After the internal combustion engine is started in the cold state and enters the idle condition, in the initial stage, due to the above structural reasons, the elimination of the valve clearance point 7 and the beginning of the occurrence of the valve clearance point 8 are respectively located above the acceleration section and the deceleration section of the working section 12, It will cause a certain impact load on the valve, but the speed of the idle condition is relatively low, so that the impact load is not too large. As the warm-up process continues, the temperature of the body and the valve and its transmission will gradually increase, and the elimination of the valve clearance point 7 and the beginning of the valve clearance point 8 will continue to increase with the expansion of the valve and its transmission mechanism. After moving forward and backward respectively, the impact load on the valve is also gradually reduced. After the internal combustion engine reaches the normal operating temperature, the elimination of the valve clearance point 7 and the beginning of the occurrence of the valve clearance point 8 respectively exceed the end point 3 of the valve opening buffer section 11 and The valve closes the starting point 5 of the buffer section 13 and is seated on the buffer section to achieve a reasonable working state. In the hot state in which the internal combustion engine is normally operated, when the cam 1 is moved to the base circle 10 in the moving direction shown in Fig. 2, the tappet is at the lowest position, the valve is closed, and when it is operated to the point 2, the tappet starts to move up, As can be seen from the above, the elimination of the valve clearance point 7 in the hot state has been displaced on the valve opening buffer section 11, so that the valve clearance is eliminated when the cam 1 is operated to the point 7, and the valve starts to open, at the end of the operation to the valve opening buffer section 11. At 3 o'clock, the lifter starts to move up, and the valve gradually opens. After crossing point 4, the valve gradually closes. In the same principle, the valve clearance point 8 that has begun to appear in the hot state has been displaced on the valve closing buffer section 13, so that when the cam 1 is decelerating When the valve reaches the starting point 5 of the valve closing section 13 and reaches 8 o'clock, the valve closes and the valve clearance begins. When the point 6 is reached, the tappet is at the lowest position.

As shown in FIG. 2, since the end point 3 of the valve opening buffer section 11 is in the cold state, a certain cam angle before the valve clearance point 7 is eliminated and the starting point 5 of the valve closing buffer section 13 are located at a certain cam angle after the start of the valve clearance point 8. Compared with the working segment 12 in FIG. 1, the working angle of the cam is extended, thereby obtaining a more full cam profile than the cam shown in FIG. 1, which increases the time of the valve opening and increases the cross-sectional value of the valve opening, thereby improving The charging efficiency and exhaust efficiency increase the power output of the internal combustion engine.

Figure 3 is a diagram showing the speed and lift variation of the valve opening buffer section in the cam profile shown in Figure _{2, where} point ₃ is the valve opening buffer section 11, point 7 is the valve clearance, 14 and 16 are the tappets. Acceleration section, 15 is the speed section of the tappet, 17 is the valve clearance, 18 is the speed, 19 is the cam angle one degree. The figure shows that the valve opening buffer section 11 is composed of an acceleration section 14 and an equal velocity section 15 for rapidly moving the tappet up to a certain position and generating a certain speed, and the speed section 15 is used. To reduce the impact load on the valve when the valve clearance is eliminated. By the same principle, the valve closing buffer section 13 of Fig. 2 is composed of an equal velocity section and a deceleration section.

The amplitude of the cam angle of the forward end of the valve opening buffer section 11 and the amplitude of the cam angle of the rearward shifting of the starting point 5 of the valve closing buffer section 13 are related to the equal speed of the valve clearance, the rocker arm ratio and the buffer section thereof, and thus are designed When entering and exhausting the cam profile, the above factors should be considered comprehensively, depending on the structure of the various internal combustion engines. The internal combustion engine is the most widely used. In order to determine the optimum range of the cam angle before the valve clearance point 7 is set in the cold state when the starting point 3 of the valve opening buffer section 11 is set, the 6105Q diesel engine, the 462Q gasoline engine and the 70 type are selected. The motorcycle gasoline engine has three sets of cam profile design. In the design of the three sets of cam profiles, the valve clearance value provided by the manufacturer is used. The cam lift amount is shown in the following table. The end point 3 of the valve opening buffer section 11 and the cam lift amount associated with the elimination of the valve clearance point 7, the same principle, these values are equally applicable to the relevant setting between the start point 5 of the valve closing buffer section 13 and the start of the valve clearance point 8.

Table 1: Intake Cam Lift Table for 6105Q Diesel Engine (Unit: mm)

Cam angle (degrees) 1 2 3 4 5 6 7 8 9 10 Acceleration 0.0002 0.0005 0.0010 0.0018 0.0028 0.0037 0 0 0 0 Speed 0.0002 0.0007 0.0017 0.0035 0.0063 0.0100 0.0100 0.0100 0.0100 0.0100 Lift 0.0002 0.0009 0.0026 0.0061 0.0124 0.0224 0.0324 0.0424 0.0524 0.0624 Cam Angle (degrees), 11 12 13 14 15 16 17 18 19 20 Acceleration 0 0 0.0005 0.0015 0.0025 0.0035 0.0045 0.0055 0.0065 0.0075 Speed 0.0100 0.0100 0.0105 0.0120 0.0145 0.0180 0.0225 0.0280 0.0345 0.0420 Lift 0.0724 0.0824 0.0929 0.1049 0.1194 0.1374 0.1599 0.1879 0.2224 0.2644 Table 2: Intake cam lift of the 462Q gasoline engine (unit: mm)

Table 3: Intake cam lift table for a 70-type motorcycle gasoline engine (unit: mm)

Table 1 shows the intake cam lift of the 6105Q diesel engine. The displacement of the engine is 6.5L. The table shows the cam angle lift before the valve clearance is eliminated in the cold state. In the cold state, the valve clearance is 0.40mm, and the rocker arm ratio is 1.546. According to the valve clearance, the gap between the cam and the tappet is multiplied by the rocker arm ratio. When the engine is in the cold state, the gap between the cam and the tappet is 0.2587mm. In the hot state, the valve and its transmission mechanism will be thermally expanded, so that the valve clearance will shrink. As for the accurate data of the expansion amount, it is difficult to measure in the working state of the engine. Generally, it is inferred from the test by the manufacturer. In other words, it is difficult to eliminate the valve clearance by the amount of thermal expansion of the valve and its transmission mechanism in the working state, so that there is a "咔嗒" valve sound during the operation of the engine. Due to the uncertainty of the amount of thermal expansion of the valve and its transmission mechanism, the lift amount in Table 1 is designed according to the amount of valve clearance remaining 30% in the hot state, that is, in the hot state, the valve clearance is 0.12mm (0.40mm multiplied by 30%), then the cam-spindle clearance in the hot state is 0.0776mm (0.12 divided by 1.546). When the cam eliminates the cam-spindle clearance, the valve begins to open. As can be seen from Table 1, the cam angle 1°-12° is the valve opening buffer section, which consists of an acceleration section of 1° to 6° and an equal velocity section of 7°-12°. When the 20° cam angle is cold, it is eliminated. In addition to the valve clearance point, the valve clearance point is eliminated when 12° is hot, and the valve opens the end point 12 of the buffer section. In the cold state, the cam angle position of 8° before the valve clearance point is eliminated, so that the working segment can be extended by at least 8° cam angle compared with the cam profile of the conventional internal combustion engine, thereby improving the fullness coefficient and the charging efficiency of the intake cam profile. . By the same principle, the valve closing buffer section can also extend the working section by at least 8 by the above design. The cam corner.

Table 2 shows the intake cam lift of the 462Q gasoline engine. The engine has a displacement of 0.8L. The table shows the cam angle lift before the valve clearance is eliminated in the cold state. In the cold state, the valve clearance is 0.13mm, the rocker arm ratio is 1.5, and the cam-rocker clearance is 0.0867rmn in the cold state. In the hot state, the residual valve clearance is calculated according to 30%. In the hot state, the valve clearance is 0.039mm. In the hot state, the cam-rocker gap is 0.026 mm, and the cam angle is 1°-8. The valve opening buffer section is composed of an acceleration section of 1° to 5° and an equal speed section of 6°-8°. When the 13° cam angle is cold, the valve clearance point is eliminated, and when the 8° cam angle is hot, the valve is eliminated. The valve clearance point, the end point of the valve opening buffer section is 8°, and the cam angle position of 5° before the valve clearance point is eliminated by 13° in the cold state, so that the working section can be extended by at least 5° cam angle compared with the cam profile of the conventional internal combustion engine. , thereby increasing the fullness coefficient and the charging efficiency of the intake cam profile. By the same principle, the valve closing buffer section can also extend the working section by a cam angle of at least 5° by the above design.

Table 3 shows the intake cam lift of the 70-type motorcycle gasoline engine. The displacement of the engine is 0.07L. The table shows the cam angle lift before the valve clearance is eliminated in the cold state. In the cold state, the valve clearance is 0.05nun, the rocker arm ratio is 1.5, and the cam-rocker clearance is 0.0333mm in the cold state. In the hot state, the residual valve clearance is calculated according to 30%. In the hot state, the valve clearance is 0.015mm. In the hot state, the cam-rocker gap is O.Olnun, and the cam angle is 1°-6°, which is the valve opening buffer section, which is composed of an acceleration section of 1° to 4° and an equal velocity section of 5°-6°, 9°. When the cam angle is cold, the valve clearance point is eliminated. When the 6° cam angle is hot, the valve clearance point is eliminated. The end point of the valve opening buffer section is 6°. In the cold state, the cam angle of 3° before the valve clearance point is eliminated by 9°. The position allows the working segment to be extended by a cam angle of at least 3° compared to the cam profile of a conventional internal combustion engine, thereby increasing the fullness factor and charging efficiency of the intake cam profile. By the same principle, the valve closing buffer section can also extend the working section by a cam angle of at least 3° by the above design.

From the intake cam lift of the three sets of vehicle internal combustion engines, it can be known that the end point of the valve opening buffer section is in the cold state, and the cam angle position of 3°-8° before the valve clearance point is eliminated, which is 0.05-0.4 mm for the valve clearance. For a vehicle internal combustion engine, it is equivalent to between 2° and 9° cam angles. In the same principle, the starting point of the valve closing buffer section is at a cam angle position of 3°-8° after the valve clearance point starts in the cold state, which is equivalent to 2°-9 for the valve clearance in the 0.05-0.4nim vehicle internal combustion engine. ° between the cam corners.

The details of the above embodiments are merely illustrative of the invention and are not intended to limit the invention, it should be understood The configuration of the valve train, the change in the valve clearance size and the speed of the buffer section, etc., etc. affect the end point 3 of the valve opening buffer section 11 or the start point 5 of the valve closing buffer section 13 before the valve clearance point 7 is eliminated in the cold state. In the cold state, the value of the cam angle position after the valve clearance point 8 starts to appear. The type of the internal combustion engine is various. For the internal combustion engine, there is a portable engine with a displacement of 50 ml or less and a displacement of 8 L or more. In addition to the internal combustion engine, heavy-duty engines, such as marine internal combustion engines, internal combustion engines, and internal combustion engines, vary in position and value due to differences in structure and numerical values. In the conventional intake and exhaust cam design techniques, the end point 3 of the valve opening buffer section 11 is set to the cold state only after the valve clearance point 7 is eliminated, and the valve clearance is started in order to start the cold state in order to eliminate the valve clearance in the cold state. When the starting point of the valve closing buffer section 13 is set to be in the cold state before the valve clearance point 8 starts to appear, it is apparent from the above description that the design is obviously not suitable for the thermal state of the normal operation of the internal combustion engine. Therefore, the present invention proposes Setting the end point 3 of the valve opening buffer section 11 to a certain cam angle after the valve clearance point 8 is eliminated before the valve clearance point 7 is eliminated and the starting point 5 of the valve closing buffer section 13 is set to the cold state, to compensate In the hot state, the valve and its transmission mechanism are subject to changes in the amount of thermal expansion, thereby extending the working section, increasing the fullness coefficient of the cam profile, and improving the charging efficiency and the exhaust efficiency. In theory, after the valve clearance is eliminated, the working section should be immediately entered to make the valve open quickly. Therefore, in the conventional cam profile design, the end point 3 of the valve opening buffer section 11 and the elimination of the valve clearance point 7 in the cold state are relatively close. Therefore, it is easy to set the end point 3 of the valve opening buffer section 11 before the valve clearance point 7 in the cold state when designing the cam profile of the present invention. Many other variations are obvious without departing from the spirit of the invention, and are considered to be within the scope of the invention.

From the above description, it can be seen that the invention has the following characteristics: It is suitable for the transformation of the internal combustion engine, has superior technical solutions, is simple to implement, has low transformation cost, is easy to popularize, and can effectively improve the charging efficiency and the exhaust efficiency, thereby improving the internal combustion engine. Power output, with good economic benefits.

Claims

Rights request

An intake and exhaust cam on a camshaft of an internal combustion engine, the cam profile including a base circle (10), a valve opening buffer section (11), a working section (12) and a valve closing buffer section (13), wherein: In the cold state, the end point (3) of the valve opening buffer section (11) is set before the valve clearance point (7) is eliminated.

The intake and exhaust cams on the camshaft of the internal combustion engine according to claim 1, wherein: in the cold state, the end point (3) of the valve opening buffer section (11) is set at the elimination of the valve clearance point (7). ) Before the 2°~9° cam angle.

The intake and exhaust cams on the camshaft of the internal combustion engine according to claim 1 or 2, wherein: the valve opening buffer section (11) is composed of an acceleration section (14) and an equal velocity section (15). .

An intake and exhaust cam on a camshaft of an internal combustion engine, the cam profile comprising a base circle (10), a valve opening buffer section (11), a working section (12) and a closing buffer section (13), characterized in that: In the cold state, the starting point (5) of the valve closing buffer section (13) is set after the start of the valve clearance point (8).

The intake and exhaust cams on the camshaft of the internal combustion engine according to claim 4, wherein: in the cold state, a starting point (5) of the valve closing buffer section (13) is set at a point where a valve clearance point begins to occur ( 8) After the 2°~9° cam angle between.

The intake and exhaust cams on the camshaft of the internal combustion engine according to claim 4 or 5, wherein: the valve closing buffer section (13) is composed of an equal velocity section and a deceleration section.