KR100827831B1 - Cylinder head - Google Patents

Abstract

In the present invention, in the cylinder head equipped with a seat ring in which the intake valve is in contact with each of the plurality of intake ports connected to the combustion chamber of the internal combustion engine, an intake port equipped with an eccentric seat ring eccentric to the center of the outer diameter, Mix the intake port equipped with the standard seat ring in which the center of outer diameter and center of inner diameter are matched. As a result, the flow coefficient is secured by the intake port equipped with the standard seat ring, and the swirl flow is strengthened by the intake port equipped with the eccentric seat ring. Compatibility becomes possible

Description

Cylinder head {Cylinder head}

The present invention relates to a cylinder head capable of improving the combustibility of a lean burn engine and maintaining high engine thermal efficiency while maintaining low NOx.

In an internal combustion engine such as a gas engine, a seat ring is attached to an opening of an intake port connected to a combustion chamber, and provides a seat surface in contact with an intake valve for opening and closing the opening.

An example of a conventional sheet ring shape is shown in FIG. This seat ring (hereinafter referred to as a standard seat ring) is annular, and its inner diameter φ A and outer diameter F are concentric, i.e., the inner diameter φ A and the outer diameter F are the same center (a). Have

In a gas engine, combustion of fuel gas and air mixture is performed by flame propagation. Therefore, active use of air flow contributes to improvement of thermal efficiency by shortening combustion time.

However, since the inner diameter phi A and the outer diameter F are concentric in the standard seat ring, the swirl ratio is small in a gas engine equipped with the standard seat ring, and it is difficult to improve the combustibility using the flow of air. .

In addition, recent diesel engines are designed such that relatively high power is obtained relative to the size of the engine. In other words, it is required to be a high BMEP (Brake Mean Effective Pressure) engine. Therefore, in order to secure the amount of air required for combustion, a high pressure ratio supercharger is employed, or the intake and exhaust port of the cylinder head also tends to be designed in a shape having a large cross-sectional area and less bending. In the port having such a shape, the flow coefficient is high, but no strong swirl flow occurs.

On the other hand, a pilot oil ignition gas engine has been developed for the purpose of purifying exhaust gas by high combustion and high output and high thermal efficiency. In this pilot oil ignition gas engine, the production cost is reduced by making the main components common with the diesel engine.

Although the cylinder head of the pilot oil ignition gas engine has a high flow coefficient for common use with a diesel engine, the swirl ratio is zero, and improvement in combustibility using air flow cannot be expected.

Accordingly, in the development of the pilot oil ignition gas engine, it is desired to improve the swirl ratio while minimizing the decrease in the flow rate coefficient in order to improve the thermal efficiency.

This invention is made | formed in view of the said situation, and an object of this invention is to provide the cylinder head which can satisfy both the maintenance of a flow coefficient which is an opposite element, and the reinforcement of swirl flow, and to improve thermal efficiency.

Next, a means for solving the problem will be described with reference to the drawings corresponding to the embodiments.

That is, the present invention, in the cylinder head equipped with a seat ring in which the intake valve is in contact with each of the plurality of intake ports connected to the combustion chamber of the internal combustion engine, the intake air is equipped with an eccentric seat ring eccentric to the center of the outer diameter The port and the intake port equipped with a standard seat ring in which the outer diameter center and the inner diameter center coincide with each other.

In this cylinder head, as a result of the mixing of the intake port with the eccentric seat ring and the intake port with the standard seat ring, the flow coefficient is secured by the intake port with the standard seat ring. The swirl is strengthened by the intake port. As a result, it is possible to satisfy both the securing of the flow coefficient, which is the opposite element, and the strengthening of the swirl flow, and a higher thermal efficiency is obtained than when only the standard seat ring is mounted or when only the eccentric seat ring is mounted.

In this case, Preferably, two intake ports are provided along the direction from the intake manifold side to the opposite side with the cylinder head interposed therebetween, and a standard seat ring is attached to one intake port, and the other intake port is provided. Mount the eccentric seat ring on the As a specific example, the camshaft is provided on the opposite side with the cylinder head interposed between the intake manifold side, and two intake ports are provided between the intake manifold side and the camshaft side of the cylinder head. A standard seat ring may be attached to the intake port, and an eccentric seat ring may be attached to the other intake port.

In this cylinder head, in a structure in which two intake ports are provided, that is, a structure having a minimum intake port necessary by implementing the present invention, a standard seat ring is mounted on one of the intake ports, and the other intake port is provided. On the eccentric seat ring is mounted. As a result, even when two intake ports are provided, it is possible to satisfy both the securing of the flow coefficient, which is the opposite element, and the strengthening of the swirl flow, and when only the standard seat ring is attached to the two intake ports, or the eccentricity. High thermal efficiency is obtained as compared with the case where only the seat ring is mounted.

More preferably, the eccentric seat ring is attached to an intake port located at a relatively distant position as viewed from the intake manifold side.

As a result, an effective swirl flow can be generated using the wall surface of the cylinder liner which is relatively far from the intake manifold side.

In this case, more preferably, two exhaust ports parallel to the two intake ports are provided in the cylinder head in parallel, and the narrow portion around the eccentric seat ring is about 45 in the direction from the manifold side toward the cam shaft side. Towards the exhaust port at an angle.

In this cylinder head, an eccentric seat ring is attached to an intake port located at a relatively distant position when viewed from the intake manifold side, and a narrow portion around the eccentric seat ring is about the direction from the manifold side toward the camshaft side. By facing the exhaust port side at an angle of 45 °, the wall surface of the cylinder liner can be effectively used, and swirl flow can be effectively generated in the combustion chamber.

In addition, since the direction of intake air is along the wall of the cylinder liner and the direction of interference is less from the intake port with a standard seat ring, the flow rate can be secured and the flow rate can be secured.

1 is a cross-sectional view of an eccentric seat ring for use in a cylinder head according to the present invention.                 

FIG. 2 is a plan view of the eccentric seat ring shown in FIG. 1. FIG.

3A is a plan view illustrating an example (No. 1) of a seat ring combination mounted on a cylinder head.

3B is a plan view illustrating an example (No. 2) of the seat ring combination mounted to the cylinder head.

3C is a plan view illustrating an example (No. 3) of the seat ring combination mounted to the cylinder head.

4: A is a top view which shows the example (No.4) of the seat ring combination mounted to the cylinder head.

4B is a plan view illustrating an example (No. 5) of the seat ring combination mounted on the cylinder head.

4C is a plan view illustrating an example (No. 6) of the seat ring combination mounted to the cylinder head.

5A is a plan view illustrating an example (No. 7) of a seat ring combination mounted on a cylinder head.

5B is a plan view illustrating an example (No. 8) of the seat ring combination mounted to the cylinder head.

5C is a plan view illustrating an example (No. 9) of the seat ring combination mounted on the cylinder head.

6A is a plan view illustrating an example (No. 10) of a seat ring combination mounted to a cylinder head.

6B is a plan view illustrating an example (No. 11) of the seat ring combination mounted on the cylinder head.

6C is a plan view illustrating an example (No. 12) of a seat ring combination mounted on a cylinder head.

7A is a plan view illustrating an example (No. 13) of a seat ring combination mounted on a cylinder head.

7B is a plan view illustrating an example (No. 14) of the seat ring combination mounted to the cylinder head.

7C is a plan view illustrating an example (No. 15) of a seat ring combination mounted on a cylinder head.

FIG. 8 is a graph showing the flow rate coefficient and the dimensionless swirl number in the variation of the seat ring combination shown in FIGS. 3A to 7C.

FIG. 9 is a plan view of a cylinder head having a seat ring configuration corresponding to combination No. 11 shown in FIG. 6B.

FIG. 10 is a graph comparing thermal efficiency between an engine having a cylinder head shown in FIG. 9 and an engine provided with only a standard seat ring.

11 is a cross-sectional view of a standard seat ring used in a conventional cylinder head.

Hereinafter, a preferred embodiment of the cylinder head according to the present invention will be described with reference to the drawings.

The present invention properly selects the mounting portion and the eccentric direction of the intake port seat ring mounted on the cylinder head of the gas engine, enhances swirl flow without lowering the flow rate coefficient, promotes air flow during combustion, It is to improve. The present invention can be applied to an engine in which combustion of a mixer is performed by flame propagation, that is, a pilot oil ignition gas engine, a spark ignition gas engine, a spark ignition gasoline engine, or the like. In addition, the engine employing the technique of the present invention is used, for example, in stationary power generation equipment for industrial or general life.

1 is a cross-sectional view of a seat ring (hereinafter referred to as an eccentric seat ring) used in a cylinder head according to the present invention, and FIG. 2 is a plan view of the eccentric seat ring shown in FIG.

The eccentric seat ring 1 shown in FIG. 1 is attached to the opening of the intake port provided in the cylinder head. The eccentric seat ring 1 includes a valve seat portion 9 having an inlet portion 5 having a hole 3 open to the intake port side, a seat surface 7 provided on the combustion chamber side and contacted with an intake valve, and a cylinder. The coupling part 11 etc. for attaching to the opening of a head are comprised.

In the eccentric seat ring 1, the outer diameter center and the inner diameter center of the hole 3 do not coincide. That is, in the eccentric seat ring 1, the inner diameter center of the hole 3 is eccentric with respect to the outer diameter center. Specifically, the circumferential surface of the inner diameter phi A having the center b eccentrically by the E from the outer diameter center a forms the inner circumferential surface of the hole 3. Here, the direction from the outer diameter center a to the inner diameter center b is called the eccentric direction of the eccentric seat ring 1.

In order to obtain such an eccentric hole 3, after forming the circumferential surface of the inner diameter phi A having the same center a as the outer diameter, the circumferential surface is cut to form the circumferential surface of the inner diameter phi B. do. As a result, as shown in FIG. 1, the part of the inner peripheral surface of the hole 3 on the opposite side to the eccentric direction of the eccentric seat ring 1 forms the circumferential surface 3a when the peripheral surface of the inner diameter phi A was formed. Although contact | connected, the other part forms the flat peripheral surface 3b toward the eccentric direction of the eccentric seat ring 1, and gradually widens up and down. The upper and lower widths of the flat circumferential surface 3b become widest on the eccentric direction side (left side in FIG. 1) of the eccentric seat ring 1.

On the other hand, in addition to the eccentric seat ring 1, the standard seat ring shown in Fig. 11 is fitted to the opening of the intake port so that the center of the outer diameter a and the center of the inner diameter phi A of the hole 3 coincide with each other. In this standard seat ring, the hole 3 and the outer diameter are concentric circles.

That is, in the cylinder head which concerns on a present Example, the intake port with which the eccentric seat ring 1 was attached, and the intake port with which the standard seat ring was mounted are mixed.

In the present embodiment, by optimally selecting the mounting portions and the eccentric direction of these eccentric seat rings 1 and the standard seat ring, it is possible to make both of the opposite elements of securing the flow rate coefficient and strengthening the swirl flow. An example thereof will be described below with reference to FIGS. 3 to 7.

3A to 7C are plan views schematically illustrating the cylinder head. This cylinder head has two openings A and B and two openings C and D in one cylinder. In these figures, the left side is the camshaft side and the right side is the manifold side (both the intake manifold and the exhaust manifold are on the same side).                 

In this cylinder head, one end of the two intake ports 13 and 14 shown by the dotted line in FIG. 3A is connected to the combustion chamber via the openings A and B. FIG. These openings A and B are opened and closed by intake valves (not shown), respectively. Although not shown, the other ends of these intake ports 13 and 14 are connected to each other so as to be upstream and downstream with respect to the flow of intake air.

The openings A and B are arranged so that the line segments passing through the openings A and B centers extend from the manifold side to the opposite side (camshaft side in the example shown in the figure).

On the other hand, the openings C and D of the exhaust port (not shown) connected to the combustion chamber are arranged in parallel with the respective openings A and B of the intake ports 13 and 14. These openings C and D are opened and closed by an exhaust valve (not shown), respectively.

Next, using the steady flow test apparatus using an impeller, the result of comparing the flow coefficient in the cylinder head shown in FIGS. 3A-7C and the intensity | strength of swirl flow is demonstrated, referring FIGS. 3A-8.

A total of 15 drawings shown in FIGS. 3A to 7C show the combination of the positions of the standard seat rings and the eccentric seat rings mounted in the respective openings A to D, and the eccentric direction of the eccentric seat rings in the steady flow test. 3A to 7C, the outer diameter center of the eccentric seat ring coincides with the opening center on which the eccentric seat ring is mounted. 3A to 7C, the arrow d indicates the eccentric direction of the eccentric seat ring.

The flow coefficients and swirls aimed at a flow coefficient of 0.51 and a dimensionless swirl coefficient of 0.134, which are about the same as those of a conventional gas engine.

This target value was adopted for the following reasons. In other words, the conventional gas engine has a low output per unit cylinder volume, and a small output of less than 1.23 MPa, and even less than 1.47 MPa when expressed using BMEP, and thus does not require much combustion air. In the design of the intake port of the cylinder head in such a conventional gas engine, the contradictory elements such as the flow coefficient and the swirl flow can be made appropriate without using a special technique. However, the output per cylinder volume is 1.47 MPa or more, preferably 1.72 MPa or more, more preferably, for the purpose of reducing the initial cost, increasing the engine power generation efficiency, reducing the operating cost, and pursuing economic feasibility. In the case of a high output of 1.96 MPa or more, a larger amount of air is required than in the prior art, and an intake port must be designed with the emphasis on the flow coefficient.

On the other hand, it is necessary to set the swirl to an appropriate value in order to promote flame propagation of the mixer starting from the ignition source in the cylinder of the gas engine and to ensure reliable combustion of the mixer. In general, however, when the output per unit cylinder volume is made high, if the flow coefficient is ensured to be the same as that of the conventional gas engine, the swirl flow cannot be at the same intensity as that of the conventional gas engine.

Therefore, in this embodiment, a flow rate coefficient of 0.51 and a dimensionless swirl number of 0.134, which are the same as those of a conventional gas engine, are aimed at maintaining the flow coefficients and swirls, which are such opposite elements, even in a high output engine. In other words, the present embodiment uses a combination of a standard seat ring and an eccentric seat ring to maintain the same flow rate coefficient and dimensionless swirl number as a conventional gas engine, thereby making the output per cylinder higher than before, The aim is to reduce operating costs by reducing costs or improving engine power generation efficiency, and to improve economics. Further, even if the present embodiment is applied to an engine having a BMEP of less than 1.23 MPa, it is possible to improve the thermal efficiency due to the enhancement of the swirl.

In FIG. 8, the flow coefficient and the dimensionless swirl number at the time of maximum valve lift in the combination of various seat rings shown in FIGS. 3A to 7C are displayed. In addition, +-of the dimensionless swirl number in the vertical axis | shaft of FIG. 8 shows the direction of a swirl flow, and as shown in FIG. 3A, counterclockwise direction is + and clockwise direction is-as seen from the bottom face of a cylinder head. .

As shown in Fig. 3A (seat ring combination No. 1), when the standard seat ring is mounted on both of the openings A and B, as shown in Fig. 8, the flow coefficient is high as 0.6 or more, The month is zero.

In contrast, as shown in Figs. 3B, 3C, 4A, 4B, 4C, and 5A, when the eccentric seat ring is attached to both of the openings A and B (combination N0.2 to N0.7), Fig. As shown in Fig. 8, the dimensionless swirl number can be increased from 0.15 to 0.2, but the flow coefficient decreases from 0.45 to 0.48.

Further, as shown in Figs. 5B, 5C, 6A, 6B, 6C, 7A, 7B, and 7C, a standard seat ring is provided on one side of the openings A and B, and an eccentric seat ring on the other side. The relationship between mounting (combination Nos. 8 to 15) and the direction of the eccentric seat ring and air flowability was evaluated.

As a result, it was shown that the target characteristic was obtained when the eccentric seat ring was attached to the opening B shown in Fig. 6B and the direction was turned inward 45 ° from the liner wall (combination No. 11).

Since the opening B is located at a position relatively far from the intake manifold side, it is considered that the effect of causing swirl flow is obtained by using the wall surface of the cylinder liner. Also in this case, a flow rate coefficient of about 0.54 to 0.55 is secured by attaching the standard seat ring to the opening A.

That is, by mixing the intake port with the eccentric seat ring 1 with the eccentric holes 3 and the intake port with the standard seat ring with the uneccentric holes 3, the standard seat ring is mounted. The flow rate coefficient is secured by the intake port, and the swirl flow is strengthened by the intake port provided with the eccentric seat ring 1.

This makes it possible to secure both the flow coefficient, which is the opposite element, and to reinforce the swirl flow, and to achieve a higher thermal efficiency than when only the standard seat ring is mounted or when only the eccentric seat ring 1 is mounted.

Example

Next, the engine which has the seat ring structure corresponding to combination No. 11 (FIG. 6B) is created, and the result of having performed the operation performance test is demonstrated.

FIG. 9 is a plan view showing a cylinder head of an engine having a seat ring configuration corresponding to combination No. 11, and FIG. 10 is a graph comparing thermal efficiency between the engine shown in FIG. 9 and an engine equipped with a standard seat ring.

The engine according to this embodiment is provided with a seat ring having a configuration of the combination N0.11 (Fig. 6B) in the cylinder head of a six-cylinder engine having a cylinder diameter of 220 mm. That is, the eccentric seat ring is attached to the intake port located at a position relatively far from the intake manifold side, and the narrow portion of the edge of the eccentric seat ring is approximately at the camshaft side as indicated by the arrow d in the figure. It is arranged toward the exhaust port at an angle of 45 degrees.

As a result, in the case of the seat ring configuration according to the present embodiment, as shown in Fig. 10, it can be seen that the thermal efficiency is 0.2 to 0.5 point higher than when the standard seat ring is mounted.

As can be seen from the results of this embodiment, the eccentric seat ring is mounted on the intake port located at a relatively distant position from the intake manifold side, and the narrow portion of the edge of the eccentric seat ring is approximately at the camshaft side. By arranging toward 45 degrees of exhaust port side, the wall surface of a cylinder liner can be utilized effectively, and swirl flow can be produced effectively with respect to a combustion chamber. In addition, since the intake air introduction direction is in the direction along the wall of the cylinder liner and less interference with the intake air from the intake port equipped with the standard seat ring, the flow coefficient can be secured while enhancing the swirl flow.

In addition, in the above-mentioned embodiment, as shown in FIG. 1, the eccentric seat ring 1 which has a left-right asymmetric shape is the convex peripheral surface 3a of the inner diameter (phi) A which has the same center as the outer diameter center a. Although the example which formed the circumferential surface of the inner diameter (phi B) in the eccentric position by cutting process was formed after forming the above, the present invention is not limited to this. For example, the inner circumference may be a convex circumferential surface over the entire circumference, or the inner circumference may be a flat circumferential surface over the entire circumference, and an eccentric sheeting having a different thickness but having substantially similar left and right shapes may be formed.

In addition, in the above-mentioned embodiment, although the eccentric seat ring 1 has the inner diameter phi B larger than the inner diameter phi A of the standard seat ring, the inner diameter of the eccentric seat ring is the standard sheet for the swirl reinforcement. It is not necessarily larger than the inner diameter of the ring. For the intake port of the cylinder head with a large flow coefficient, the inner diameter of the eccentric seat ring 1 may be made smaller than that of the standard seat ring. However, in a realistic design, since the flow coefficient and swirl flow are opposite characteristics, it is preferable to make the inner diameter of the eccentric seat ring larger than the inner diameter of the standard seat ring.

In addition, in the above-mentioned embodiment, as shown by the dotted line in FIG. 3A, two intake ports 13 and 14 are respectively connected to the combustion chamber, and the other end of each intake port 13 and 14 is upstream with respect to the flow of intake air. Although the example connected to each other so that it might become a downstream relationship was shown, it is good also as a structure which connects each intake port to an intake manifold independently.

In addition, in the above-mentioned embodiment, although the example which showed the left side to the camshaft side and the right side to the manifold side (both intake manifold and exhaust manifold are in the same side) was shown in FIGS. 3A-7C, The manifold may be provided on the cam shaft side so as to be located on the opposite side, and the intake manifold may face the exhaust manifold through the cylinder.

Claims (7)

In the cylinder head is provided with a seat ring in which the intake valve is in contact with each of a plurality of intake ports connected to the combustion chamber of the internal combustion engine, Two intake ports are provided along the direction from the intake manifold side to the opposite side with the cylinder head interposed therebetween, Two exhaust ports are provided in parallel with the cylinder head so as to be parallel to the two intake ports, An eccentric seat ring in which the inner diameter center is eccentric with respect to the outer diameter center is attached to the intake port located at a relatively distant position from the intake manifold side, and the outer intake port is made to coincide with the outer diameter center and the inner diameter center. In addition to being equipped with a standard seat ring, A narrow head of the edge of the eccentric seat ring faces the exhaust port side at an angle of 45 ° with respect to the direction from the manifold to the camshaft side. delete In the cylinder head is provided with a seat ring in which the intake valve is in contact with each of a plurality of intake ports connected to the combustion chamber of the internal combustion engine, Two intake ports are provided between the intake manifold side and the camshaft side in a direction from the intake manifold side to the opposite side with the cylinder head interposed therebetween, Two exhaust ports are provided in parallel with the cylinder head so as to be parallel to the two intake ports, An eccentric seat ring in which the inner diameter center is eccentric with respect to the outer diameter center is attached to the intake port located at a relatively distant position from the intake manifold side, and the outer intake port is made to coincide with the outer diameter center and the inner diameter center. In addition to being equipped with a standard seat ring, A narrow head of the edge of the eccentric seat ring faces the exhaust port side at an angle of 45 ° with respect to the direction from the manifold to the camshaft side. delete delete delete delete

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