JPH04116608U - Engine combustion chamber structure - Google Patents

Abstract

(57) [Summary] (with amendments) [Configuration] The angle of inclination of the exhaust valve with respect to the axial direction of the cylinder is larger than the angle of inclination of the intake valve with respect to the axial direction of the cylinder, and the exhaust valve seat 9 is The intersection Po of the plane including the valve seat surface 9a of the exhaust valve seat 9 and the straight line 10 passing through the axis of the cylinder is the intersection point Po of the plane including the valve seat surface 8a of the intake valve seat 8 and the above straight line 1.
It is provided at a position farther from the piston than the intersection point Pi with the straight line passing through 0. [Effect] Freewheeling is possible without reducing the strength of the piston due to the deepening of the recessed portion of the piston.

Description

[Detailed explanation of the idea]

0001

[Industrial application field]

This invention is an engine equipped with an exhaust valve on the upper wall of the combustion chamber that opens and closes the exhaust port. This concerns the combustion chamber structure.

0002

[Conventional technology]

Conventionally, in engines, there is a method disclosed in, for example, Japanese Utility Model Application Publication No. 64-53421. The cylinder head, which forms the upper wall of the combustion chamber, is The intake and exhaust valves that open and close the intake and exhaust ports have almost the same slope. arranged at an angle.

0003

[Problem that the idea aims to solve]

However, considering the intake efficiency, the above intake port is not formed straight. It is better to Therefore, for example, in a V-type engine, the If the intake manifold extends downward and is connected to the intake port, The intake port has a relatively small inclination angle with respect to the axial direction of the cylinder. is formed. Along with this, the angle of inclination of the intake valve relative to the cylinder axis direction has also changed. It is provided in a state where it becomes smaller. On the other hand, the exhaust port is located below the engine. The cylinder is connected via the exhaust pipe extending downward and the exhaust manifold extending downward. The angle of inclination with respect to the axial direction is large. Along with this, the exhaust valve The lubricant is also provided with a large inclination angle with respect to the axial direction of the cylinder.

0004 As mentioned above, if an intake valve and an exhaust valve are provided, the exhaust valve Since the gap between the and the piston becomes narrower, in order to avoid interference between the two, as shown in Figure 4, In other words, a depression, that is, a recessed portion 52 is formed on the upper surface side of the piston 51. and, When the inclination angle of the exhaust valve 53 is large, it is necessary to form the recess portion 52 deeply. In such cases, the thickness t of the piston end becomes thinner, resulting in insufficient strength. There is a problem that there is a possibility that

[0005]

[Means to solve the problem]

The combustion chamber structure of the engine according to the invention of claim 1 is a system that solves the above problems. The inclination angle of the exhaust valve with respect to the cylinder axial direction is In an engine combustion chamber structure whose angle of inclination is larger than that of the intake valve, the following We are taking the following measures.

[0006] That is, the valve seat of the above exhaust valve includes the valve seat surface of the exhaust valve. The intersection of the plane and the straight line passing through the axis of the cylinder includes the valve seat surface of the intake valve. The position is further away from the piston than the intersection of the surface facing the piston and the straight line passing through the axis of the cylinder. It is set up so that

[0007] The combustion chamber structure of the engine according to the invention of claim 2 is designed to solve the above problem. The inclination angle of the exhaust valve with respect to the cylinder axial direction is The angle of inclination is larger than that of the intake valve, temporarily causing the exhaust valve to open and In the combustion chamber structure of an engine where the intake valve is opened at the same time, the following steps should be taken. I am taking dan.

[0008] In other words, each cylinder has multiple exhaust valves and intake valves. The valve seat of the exhaust valve includes a valve seat surface of the exhaust valve. The intersection of the surface and the straight line passing through the axis of the cylinder includes the valve seat surface of the intake valve. The position is further away from the piston than the intersection of the surface and the straight line passing through the axis of the cylinder. It is set up like this.

[0009]

[Effect]

According to the structure of claim 1, the valve seat of the exhaust valve is The intersection of the plane including the seat surface and the straight line passing through the axis of the cylinder is the valve of the intake valve. The distance from the piston is greater than the intersection of the surface including the seat surface and the straight line passing through the axis of the cylinder. The valve seat position of the exhaust valve is , the position is retracted away from the piston. Along with this, the exhaust valve The position is also retracted in the direction away from the piston, so the axis of the cylinder Even if the angle of inclination of the exhaust valve with respect to the direction is large, the piston Interference between the exhaust valve and piston can be prevented without making the recess deep. can.

0010 According to the structure of claim 2, in addition to the effect of the structure of claim 1, the intake port is It is possible to suppress air taken in through the exhaust port from blowing through to the exhaust port.

[0011] In other words, for example, in an engine with 4 valves per cylinder, the number of valves is large. Therefore, the intake valve and the exhaust valve are provided close to each other. And this In such an engine, the exhaust valve is temporarily open and the intake valve is open. If both occur at the same time, the air taken in through the intake port will be exhausted as is. A blow-through to the air port is likely to occur. However, the combustion chamber of this engine In the structure, the position of the valve seat of the exhaust valve regresses away from the piston. In other words, the opening of the exhaust port on the combustion chamber side Retract in the direction away from the piston relative to the opening on the intake port side on the baking chamber side. Therefore, the above-mentioned blow-by of the intake air can be suppressed.

0012

【Example】

An embodiment of the present invention will be described below with reference to FIGS. 1 to 3.

[0013] As shown in Figure 1, the engine has a cylinder head 1 on the bottom surface corresponding to each cylinder. A combustion chamber 2 is formed. The cylinder head 1 communicates with the combustion chamber 2 mentioned above. An intake port 3 and an exhaust port 4 are formed. Intake port 3 has an An intake valve 5 is provided to open and close an opening on the combustion chamber 2 side in the air port 3. The air port 4 has an exhaust valve that opens and closes the opening on the combustion chamber 2 side of the exhaust port 4. 6 is provided.

[0014] An intake manifold (not shown) extending from above is connected to the intake port 3 above. In consideration of intake efficiency, the intake port 3 is located relatively close to the axis of the cylinder. It is formed with a small inclination angle with respect to the direction. Along with this, the intake valve The tube 5 is also provided with a small angle of inclination with respect to the axial direction of the cylinder.

[0015] On the other hand, the exhaust port 4 is connected to an exhaust pipe (not shown) provided below the engine. , is connected via the exhaust manifold that extends downward, so that the axial direction of the cylinder It is formed with a large inclination angle relative to the Along with this, the exhaust valve 6 The cylinder is also provided with a large inclination angle with respect to the axial direction of the cylinder.

[0016] In this embodiment, the engine is a V-type engine, and each combustion chamber 2 has two intakes. It is equipped with air valves 5, 5 and two exhaust valves 6, 6. Therefore, as shown in Figure 2 As shown, the surface of the cylinder head 1 facing the combustion chamber 2, which is formed together with the cylinder 7, Two openings for the intake port 3 and two openings for the exhaust port 4 are formed. . Additionally, the engine temporarily maintains the open state of the intake valve 5 and the open state of the exhaust valve 6. This is a Miller cycle engine where both occur at the same time.

[0017] An intake valve seat 8 is provided at the opening of the intake port 3, and an intake valve seat 8 is provided at the opening of the intake port 3. An exhaust valve seat 9 is provided in the opening of the exhaust valve 4 . Exhaust valve seat 9 As shown in FIG. 3, the valve seat surface 9a, which is the lower surface of the exhaust valve seat 9, is The intersection Po of the plane including the straight line 10 passing through the axis of the cylinder 7 is the intake valve seat 8. (not shown) from the intersection point Pi of the plane including the valve seat surface 8a and the above-mentioned straight line 10. It is located far away from the piston. That is, the exhaust valve seat The valve seat 9 is offset upwardly with respect to the intake valve seat 8.

[0018] In addition, the inner diameter of the exhaust valve seat 9 is the part where the exhaust valve seat 9 is provided. It is smaller than the inner diameter of exhaust port 4 at the position, suppressing backflow of exhaust gas. has been done.

[0019] The above-mentioned intake valve 5 and exhaust valve 6 are each valve motor provided above them. 11 to open and close the corresponding intake and exhaust ports 3 and 4. The sea urchin is turning. In the valve train 11, a tappet hole formed in the cylinder head 1 A bucket-shaped tappet 13 is attached to each of the wheels 12, 12. Each tapete The valve lash mechanism 14 is connected to the tappet 13 through a fluid-type valve lash mechanism 14 built into the tappet 13. Then, the valve stem 5a of the intake valve 5 or the valve stem 6a of the exhaust valve 6 is connected. A spring 15 is installed between the tappet 13 and the cylinder head 1. The spring 15 exerts an upward pushing force on the tappet 13. has been added.

[0020] With the above configuration, the tappet 13 is connected to the cylinder from the tappet hole 12. exposed on the upper surface of the head 1, and each It is pressed into contact with the camshafts 16 disposed directly above. Also, tappet 13. 13 slides inside the tappet hole 12 to drive the intake and exhaust valves 5 and 6. When the tappet 13 and the camshaft 1 are Complete contact with 6 is maintained.

[0021] In the above configuration, when the camshafts 16 rotate, each cam surface causes Then, the tappets 13, 13, that is, the intake valve 5 and the exhaust valve 6 slide up and down. , an intake action and an exhaust action on the combustion chamber 2 are performed. On the other hand, for example Kamsha Due to a malfunction of the lift 16, the exhaust valve 6 is kept in the open position at its lowest position. The term "held" means a recess formed in the piston corresponding to the exhaust valve 6, i.e., as shown in the figure. The piston and exhaust valve 6 are prevented from interfering, and the piston is Freewheeling properties of the engine are ensured. In this case, as mentioned above, the exhaust valve The seat 9 is relative to the intake valve seat 8, i.e. the exhaust valve 6 is relative to the intake valve 5. The above recess is small because it is offset upward. It is now possible to deal with this situation. This prevents the strength of the piston from decreasing. There is.

[0022] Additionally, this engine temporarily maintains the open state of the intake valve 5 and the open state of the exhaust valve 6. It is a Miller cycle engine that simultaneously generates the Since the intake valve and exhaust valve are close to each other, normally intake port 3 is Air taken in through the exhaust port 4 can easily blow through to the exhaust port 4. However, the book In the engine, as mentioned above, the exhaust valve seat 9 is relative to the intake valve seat 8. In other words, the opening of the exhaust port 4 on the combustion chamber 2 side is connected to the intake port on the combustion chamber 2 side. It is offset upwards with respect to the opening on the air port 3 side, so The above-mentioned intake air blow-through is suppressed.

[0023]

[Effect of the idea]

As described above, the combustion chamber structure of the engine according to the invention of claim 1 has the valve of the exhaust valve. The valve seat is a straight line that passes through the plane that includes the valve seat surface of the exhaust valve and the axis of the cylinder. The intersection with is a straight line passing through the plane that includes the valve seat surface of the intake valve and the axis of the cylinder. The configuration is such that it is located further away from the piston than the intersection with the piston. Ru.

[0024] This prevents the strength of the piston from decreasing due to the deep recess of the piston. This prevents interference between the exhaust valve and piston and improves freewheeling. This has the effect of making it possible to make the system more flexible.

[0025] The combustion chamber structure of the engine according to the invention of claim 2 has the exhaust valve and the intake valve as described above. A plurality of valves are provided for each cylinder, and the exhaust valve valve The seat is defined by a straight line passing through the plane including the valve seat surface of the exhaust valve and the axis of the cylinder. The intersection of is the straight line passing through the plane that includes the valve seat surface of the intake valve and the axis of the cylinder. The configuration is such that it is located further away from the piston than the intersection of .

[0026] As a result, in addition to the effect of the invention of claim 1, the air taken in through the intake port This has the effect of suppressing air from blowing into the exhaust port.

[Brief explanation of drawings]

FIG. 1 is a longitudinal sectional view of a cylinder head of an engine showing an embodiment of the present invention.

FIG. 2 is a view of the combustion chamber with the intake valve and exhaust valve removed, as seen from the direction C shown in FIG. 1;

FIG. 3 is a sectional view taken along line A-A in FIG. 2;

FIG. 4 is an explanatory diagram of an assessment section in a conventional engine.

[Explanation of symbols]

1 cylinder head 1 2 Combustion chamber 3 Intake port 4 Exhaust port 5 Intake valve 6 Exhaust valve 8 Intake valve seat 8a Valve seat surface 9 Exhaust valve seat 9a Valve seat surface

Claims (2)

[Scope of utility model registration request] [Claim 1] In an engine combustion chamber structure in which the angle of inclination of the exhaust valve with respect to the axial direction of the cylinder is larger than the angle of inclination of the intake valve with respect to the axial direction of the cylinder, the valve seat of the exhaust valve is , the intersection of the plane containing the valve seat surface of the exhaust valve and a straight line passing through the axis of the cylinder is farther from the piston than the intersection of the plane containing the valve seat of the intake valve and a straight line passing through the axis of the cylinder. A combustion chamber structure of an engine, characterized in that the combustion chamber is provided in such a manner that the combustion chamber is located at a certain position. 2. The angle of inclination of the exhaust valve with respect to the axial direction of the cylinder is larger than the angle of inclination of the intake valve with respect to the axial direction of the cylinder, so that the open state of the exhaust valve and the open state of the intake valve are temporarily changed. In the combustion chamber structure of an engine in which these conditions occur simultaneously, a plurality of the above-mentioned exhaust valves and intake valves are provided per cylinder, and the valve seat of the exhaust valve is separated from the surface including the valve seat surface of the exhaust valve. The point of intersection with the straight line passing through the axis of the cylinder is located further away from the piston than the point of intersection between the plane including the valve seat surface of the intake valve and the straight line passing through the axis of the cylinder. Characteristic combustion chamber structure of the engine.