JP3018849B2 - Cylinder head of internal combustion engine - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an improvement in a cylinder head of an internal combustion engine.

[0002]

2. Description of the Related Art An exhaust valve of an internal combustion engine is exposed to combustion gas and is under a severe thermal environment, and high cooling performance is required.

As a cylinder head of a conventional internal combustion engine,
For example, there is one shown in FIG.
141 publication).

To explain this, an intake port 7 for introducing intake air into the combustion chamber 2 and an exhaust port 6 for discharging exhaust gas from the combustion chamber 2 are formed in the cylinder head 1. The cylinder head 1 is of a so-called cross-flow type in which an intake port 7 and an exhaust port 6 are opened on the left and right side walls 16 and 14, respectively.

The cylinder head 1 has an intake valve 3 that opens and closes an intake port 7 with respect to the combustion chamber 2, an exhaust valve 4 that opens and closes an exhaust port 6 with respect to the combustion chamber 2, and intake and exhaust valves 3, 4.
There is provided a valve mechanism for opening and closing the motor through the rocker arm 10 and a cam (not shown) in synchronization with the rotation of the engine.

The heat received by the intake / exhaust valves 3 and 4 from the combustion gas is transferred to the cylinder head 1 via the valve seat 8 and the valve guide 9, and is transmitted to the cooling water and the outside air circulating from the cylinder head 1 through the water jacket 8. Heat is dissipated.

[0007]

However, in such a conventional cylinder head 1 of an internal combustion engine, the intake valve 4 is exposed to low-temperature intake air flowing through the intake port 7 to promote heat dissipation. Since the exhaust valve 4 is exposed to the high-temperature exhaust gas flowing through the exhaust port 6 and is heated, the exhaust valve 4 may be heated to cause knocking or the like.

There is also a need to generate a vortex in the intake air flowing into the combustion chamber from the intake port 7 to promote air flow in the combustion chamber to reduce ignition delay and increase combustion speed.

However, when the intake port 7 is inclined so as to be along the cylinder direction to generate a vertically swirling vortex, that is, a tumble, in the intake air flowing into the combustion chamber 2, such a conventional cylinder is used. In the head 1, the intake port 7 and the exhaust port 6 extend from the combustion chamber 2 in the left-right direction of the cylinder head 1, so that the inclination angle of the intake port 7 is restricted, and the combustion chamber 2
There is a problem that a strong tumble cannot be generated.

The present invention has been made in view of the above problems, and has as its object to generate a strong tumble in the intake air and enhance the cooling performance of the exhaust valve.

[0011]

According to the first aspect of the present invention,
An intake port for introducing intake air into the combustion chamber, an exhaust port for discharging exhaust gas from the combustion chamber, an intake valve for opening and closing the intake port with respect to the combustion chamber, and an exhaust valve for opening and closing the exhaust port with respect to the combustion chamber. In a cylinder head of an internal combustion engine having a valve mechanism that opens and closes an intake / exhaust valve in synchronization with rotation of the engine, both the intake port and the exhaust port are opened on one side wall, and the intake port is connected to the exhaust port. And the stem of the exhaust valve penetrates both the exhaust port and the intake port.

According to a second aspect of the present invention, in the first aspect, a fuel injection valve for supplying fuel to an intake port is provided, and a fuel injection direction of the fuel injection valve is directed to a stem portion of the exhaust valve.

[0013]

According to the first aspect of the present invention, the intake port is formed alongside the exhaust port so that the intake port can be connected to the combustion chamber along the cylinder. For this reason, a strong tumble is generated in the air-fuel mixture flowing into the cylinder through the intake port as the piston descends. By enhancing the tumble, it is possible to promote air flow in the combustion chamber, reduce ignition delay, increase combustion speed, and improve engine output and fuel economy.

Since the stem of the exhaust valve is provided through the intake port, the heat received by the exhaust valve from the combustion gas is exposed to the low-temperature intake air flowing through the intake port, so that the heat is radiated. . As a result, it is possible to sufficiently secure the cooling property of the exhaust valve, to improve the heat resistance thereof, and to suppress the occurrence of knocking and the like.

According to the second aspect of the present invention, since the fuel injection direction of the fuel injection valve is directed to the stem of the exhaust valve, the fuel injected from the fuel injector collides with the stem of the exhaust valve, and the fuel is injected from the exhaust valve. The heat radiation to is promoted.

Further, the fuel spray injected from the fuel injection valve is heated by the stem of the high-temperature exhaust valve, so that the atomization of the fuel is promoted and the combustibility is enhanced.

[0017]

Embodiments of the present invention will be described below with reference to the accompanying drawings.

As shown in FIGS. 1 and 2, a combustion chamber 2 is defined in a cylinder head 1 between a piston 5 and two intake ports 7 for introducing intake air into one combustion chamber 2. Two exhaust ports 6 for discharging exhaust gas from the combustion chamber 2 are formed. The cylinder head 1 is of a so-called counter flow type, in which each intake port 7 and each exhaust port 6 open on the left side wall 16 of the cylinder head 1.

The cylinder head 1 has two intake valves 3 for opening and closing each intake port 7 with respect to the combustion chamber 2, two exhaust valves 4 for opening and closing each exhaust port 6 with respect to the combustion chamber 2,
A valve mechanism for opening and closing the intake and exhaust valves 3 and 4 in synchronization with the rotation of the engine via a cam 11, a lifter 12, a valve spring 13 and the like is provided.

In FIG. 2, reference numeral 15 denotes a plug post through which an unillustrated ignition plug is inserted. The ignition plug is disposed between the intake and exhaust valves 3 and 4 so as to face the center of the combustion chamber 2.
In the figure, reference numeral 29 denotes a boss for fitting the lifter 12, 26, 2
Reference numeral 7 denotes a hole for fitting each of the valve guides 32 and 42, and reference numeral 25 denotes a joining flange portion for a rocker cover (not shown).

Assuming that the direction in which the crankshaft (not shown) to which the connecting rod 19 is connected to the cylinder 20 accommodating the piston 5 is located downward and the direction in which the combustion chamber 2 is located upward, each intake port 7 is provided with each exhaust port. It is arranged above the port 6 side by side.

Each intake port 7 has a downstream portion 21 extending substantially parallel to the cylinder 20 from the combustion chamber 2, a curved portion 22 curved from the downstream portion 21 along the exhaust port 6, and a curved portion 22.
Upstream portion 23 extending in a direction substantially orthogonal to cylinder 20 from
Having.

The stem 31 of the intake valve 3 is provided through the intake port 7. A valve guide 32 is press-fitted into the cylinder head 1, and a stem portion 31 is slidably supported via the valve guide 32.

The stem portion 41 of the exhaust valve 4 is provided to penetrate both the exhaust port 6 and the intake port 7. A valve guide 42 is press-fitted into the upper deck portion 17 of the cylinder head 1, a valve guide 43 is press-fitted into the port partition portion 18, and a stem portion 41 is inserted through each valve guide 42, 43.
Are slidably supported.

The cylinder head 1 has an intake / exhaust port 7,
A water jacket 8 is formed around 6. Cooling water sent from a water pump (not shown) circulates through the water jacket 8 to remove heat from the cylinder head 1.

A manifold 50 is connected to the left side wall 16 of the cylinder head 1. In the manifold 50, an intake pipe 51 communicating with each intake port 7 and an exhaust pipe 52 communicating with each exhaust port 6 are integrally formed.

A fuel injection valve 60 for supplying fuel to each intake port 7 is provided. A mounting boss 53 for the fuel injection valve 60 is formed integrally with the manifold 50.

The fuel injection valve 60 is arranged so that its fuel injection direction is directed to the stem 41 of the exhaust valve 4.

The operation will be described below.

In the intake stroke in which the piston 5 descends, the intake valve 3 is lifted, and the air introduced from the intake pipe 51 is mixed with the fuel injected from the fuel injection valve 60 and passes through each intake port 7 to the combustion chamber. Inhaled in 2.

By forming the intake port 7 side by side above the exhaust port 6, it is possible to arrange the downstream portion 21 of the intake port 7 along the cylinder 20. For this reason, a strong tumble is generated in the air-fuel mixture flowing into the cylinder 20 through the intake port 7. By strengthening the tumble, the air flow in the combustion chamber 2 is promoted to reduce the ignition delay, the combustion speed is increased, and the output of the engine and the fuel consumption can be improved.

The heat received by the intake / exhaust valves 3 and 4 from the combustion gas is transferred to the cylinder head 1 via the valve seat 8 and the valve guides 32, 42 and 43 maintained at a temperature in the range of, for example, 600 to 800K. The heat is radiated from the cylinder head 1 to the cooling water or the outside air maintained in a temperature range of, for example, 360 to 380 K circulating through the water jacket 8.

In addition, since the intake valve 4 is exposed to intake air at, for example, 310 to 330 K flowing through the intake port 7 to promote heat radiation, sufficient cooling performance can be ensured.

On the other hand, the exhaust valve 4 is heated by being exposed to high-temperature exhaust gas flowing through the exhaust port 6, but flows through the intake port 7 because the stem portion 41 is provided through the intake port 7. Exposure to low-temperature intake air promotes heat dissipation.

Further, since the fuel injected from the fuel injection valve 60 collides with the stem 41 of the exhaust valve 4, the exhaust valve 4
The heat release to the fuel is promoted.

As a result, it is possible to sufficiently secure the cooling property of the exhaust valve 4, to improve its heat resistance, and to suppress the occurrence of knocking and the like.

The fuel spray injected from the fuel injection valve 60 is heated by the stem 41 of the high-temperature exhaust valve 4, so that atomization of the fuel is promoted and the combustibility is enhanced.

Next, another embodiment shown in FIG. 3 will be described. The parts corresponding to those in FIG. 1 are denoted by the same reference numerals.

A valve guide 42 slidably supporting the stem 41 of the exhaust valve 4 is press-fitted into the upper deck portion 17 of the cylinder head 1, while the stem 41 is slid directly into the port partition 18. A valve guide hole 45 to be freely inserted is formed.

The cylinder head 1 is made of an aluminum alloy, and the guide portion 46 facing the valve guide hole 45 and the exhaust port 6 is formed by spraying a copper-based metal having a higher thermal conductivity than the aluminum alloy with a laser. You.

In this case, the heat that the exhaust valve 4 receives from the combustion gas is promoted to be transmitted from the stem portion 41 to the cylinder head 1 through the valve guide portion 46 having a high thermal conductivity. The amount of heat released to the cooling water circulating through the nozzle 8 is increased.

[0042]

As described above, according to the first aspect of the present invention, the intake port for introducing intake air into the combustion chamber, the exhaust port for discharging exhaust gas from the combustion chamber, and the opening and closing of the intake port with respect to the combustion chamber. One side wall of a cylinder head of an internal combustion engine including an intake valve, an exhaust valve that opens and closes an exhaust port with respect to a combustion chamber, and a valve mechanism that drives the intake and exhaust valves to open and close in synchronization with rotation of the engine. Because both the intake port and the exhaust port are open in the section, the intake port is formed side by side above the exhaust port, and the stem part of the exhaust valve is penetrated through both the exhaust port and the intake port. A strong tumble is generated in the inflowing air-fuel mixture to improve engine output and fuel efficiency, while the exhaust valve stem is exposed to low-temperature intake air flowing through the intake port to promote heat radiation. A result, the enhanced heat resistance of the exhaust valve, is suppressed the occurrence of knocking or the like.

According to a second aspect of the invention, in the first aspect of the invention, a fuel injection valve for supplying fuel to the intake port is provided, and the fuel injection direction of the fuel injection valve is directed to the stem of the exhaust valve. The fuel injected from the injection valve collides with the stem of the exhaust valve, and the radiation of the fuel from the exhaust valve to the fuel is promoted. Is enhanced.

[Brief description of the drawings]

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

FIG. 2 is a plan view of the cylinder head.

FIG. 3 is a cross-sectional view of an engine showing another embodiment.

FIG. 4 is a sectional view of a cylinder head showing a conventional example.

[Description of Signs] 1 Cylinder head 2 Combustion chamber 3 Intake valve 4 Exhaust valve 5 Piston 6 Exhaust port 7 Intake port 11 Cam 20 Cylinder 41 Exhaust valve stem 42 Valve guide 43 Valve guide 45 Valve guide hole 46 Valve guide 60 Fuel Injection valve

──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. ⁷ Identification code FI F02B 23/08 F02B 23/08 S 31/00 31/00 Z F02M 31/135 F02M 69/04 P 69/04 31/12 301T (58) Field surveyed (Int.Cl. ⁷ , DB name) F02F 1/42 F01L 1/26 F01P 1/08 F02B 23/00-23/10 F02B 31/00 F02M 31/135 F02M 69/04 F01L 3 / 08

Claims (2)

(57) [Claims] An intake port for introducing intake air into the combustion chamber; an exhaust port for discharging exhaust gas from the combustion chamber; an intake / exhaust valve for opening / closing the intake / exhaust port with respect to the combustion chamber; In the cylinder head of an internal combustion engine having a valve mechanism that opens and closes in synchronization with the rotation of the engine, both the intake port and the exhaust port are opened on one side wall, and the intake port is arranged above the exhaust port. A cylinder head for an internal combustion engine, wherein the cylinder head is formed and a stem portion of an exhaust valve passes through both an exhaust port and an intake port. 2. A cylinder head for an internal combustion engine according to claim 1, wherein a fuel injection valve for supplying fuel to the intake port is provided, and a fuel injection direction of the fuel injection valve is directed to a stem portion of the exhaust valve.