JPH05133252A - Four cycle engine - Google Patents

Abstract

PURPOSE:To improve riding feeling and perform lean burning to improve fuel consumption. CONSTITUTION:A combustion chamber 5 is formed of the piston 2 contained in a cylinder block 1 and the cylinder head 6 mounted on the cylinder block 1. In a four cycle engine comprising this combustion chamber 5 provided with air intake valves 11A and 11B and exhaust valves 12A and 12B, partition walls 13 and 14 are formed at each central position of the cylinder head and/or piston where two air intake valves and exhaust valves are arranged to divide into two chambers. In a divided combustion chamber 5A, 5B, air-fuel mixture of a theoretical air-fuel ratio is supplied, and air-fuel ratio of air-fuel mixture to be supplied in the other divided combustion chamber 5B, 5A can be varied according to an engine load.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a four-cycle engine, and more particularly to improvement of a combustion chamber of a four-cycle engine.

[0002]

2. Description of the Related Art Among gasoline engines, an engine having a variable number of operating cylinders has been conventionally proposed for the purpose of improving fuel efficiency. In the case of a four-cycle engine, for example, this variable cylinder number engine operates all four cylinders at full engine load, but cuts off the ignition of, for example, two cylinders out of four cylinders at partial engine load,
It is configured to operate only two cylinders. In this way, by increasing or decreasing the number of operating cylinders,
It is trying to save fuel supply to the engine and improve fuel efficiency.

[0003]

However, in the engine with variable number of operating cylinders as described above, the cylinders that operate when the ignition is cut or re-ignited are changed, so that the impact at that time is large and a smooth riding feeling is obtained. May be damaged.

The present invention has been made in consideration of the above circumstances, and it is possible to improve leaning and fuel consumption while improving the ride feeling.
The purpose is to provide a cycle engine.

[0005]

According to the present invention, a combustion chamber is formed by a piston housed in a cylinder block and a cylinder head installed in the cylinder block.
In a four-cycle engine in which two intake valves and two exhaust valves are arranged in the combustion chamber, at least one of the cylinder block and the piston has two intake valves and two exhaust valves. A partition wall is formed at a central position, the combustion chamber is divided into two, one of the divided combustion chambers is supplied with a mixture having a stoichiometric air-fuel ratio, and the other of the divided combustion chambers is supplied with an air-fuel ratio of an engine load. It is configured to be variable according to

[0006]

Therefore, according to the four-cycle engine of the present invention, one of the split combustion chambers is always supplied with the stoichiometric air-fuel ratio, while the other split combustion chamber is supplied with the air-fuel ratio of the air-fuel mixture. Therefore, when the engine is at low and medium loads, a lean mixture with a thin fuel and a large air-fuel ratio is supplied to the other split combustion chamber. Therefore, lean burn is possible in the other split combustion chamber, and the fuel economy of the engine as a whole can be improved.

[0007]

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

FIG. 1 is a sectional view around the engine combustion chamber showing a first embodiment of a four-cycle engine according to the present invention, and FIG.
4 is a sectional view taken along line III-III in FIG. 1, and FIG. 4 is a schematic view showing a combustion chamber and an intake system of the engine of FIG.

The four-cycle engine in this embodiment is an in-line four-cylinder engine in which four cylinders (cylinders) 3 for accommodating pistons 2 are arranged in series in a cylinder block 1 as shown in FIG. The piston 2 is connected to one crankshaft (not shown) via a connecting rod 4, and this crankshaft is connected to the cylinder block 1
Is rotatably housed in a crankcase (not shown) for installing the.

A cylinder head 6 that forms an individual combustion chamber 5 with each piston 2 is installed on the cylinder block 1, and a head cover (not shown) is mounted on the cylinder head 6. As shown in FIG. 2, the cylinder head 6 has an L side intake hole 7A and an R side intake hole 7B, and an L side exhaust hole 8A and an R side exhaust hole 8 for each combustion chamber 5.
B is opened. From these L side intake holes 7A and R side intake holes 7B, as shown in FIG. 3, L side intake ports 9A,
The R side intake port 9B extends, and the L side exhaust hole 8
An L side exhaust port 10A and an R side exhaust port 10B extend from the A and R side exhaust holes 8B, respectively. These L-side exhaust port 10A and R-side exhaust port 10B are formed so as to join.

Further, as shown in FIG. 3, the L side intake hole 7
An L side intake valve 11A and an R side intake valve 11B are arranged in the A and R side intake holes 7B, respectively, and an L side exhaust hole 8A,
An L-side exhaust valve 12A and an R-side exhaust valve 12B are arranged in the R-side exhaust hole 8B, respectively. The L-side intake valve 11A and the R-side intake valve 11B, and the L-side exhaust valve 12A and the R-side exhaust valve 12B are operated according to the process of the 4-cycle engine by a valve operating device (not shown). That is, the L-side intake valve 11A and the R-side intake valve 11B are used for intake, compression, and
Of the processes of explosion and exhaust, the intake process is opened to introduce the air-fuel mixture into the combustion chamber 5, and the L-side exhaust valve 1
The 2A and R side exhaust valves 12B are opened in the exhaust process to discharge the waste gas from the combustion chamber 5.

Now, each combustion chamber 5 is, as shown in FIG.
It is divided into an L-side split combustion chamber 5A and an R-side split combustion chamber 5B. In this section, a piston-side partition wall 13 erected on the top surface of the piston 2 and a cylinder head-side partition wall 14 vertically installed in the combustion chamber 5 of the cylinder head 6 come into contact with each other at the top dead center of the piston 2. It is composed of

As shown in FIG. 2, the cylinder head side partition wall 14 extends from the central position of the L side intake hole 7A and the R side intake hole 7B to the central position of the L side exhaust hole 8A and the R side exhaust hole 8B. The partition wall 13 on the piston side is formed corresponding to the position of the partition wall 14 on the cylinder head side.
Therefore, the L-side intake valve 11A is installed in the L-side split combustion chamber 5A.
And an L side exhaust valve 12A are arranged, and an R side intake valve 11B and an R side exhaust valve 1 are provided in the R side split combustion chamber 5B.
2B is arranged. Further, in the cylinder head 6, one L-side split combustion chamber 5A and one R-side split combustion chamber 5B are provided.
The side spark plug 15A and the R side spark plug 15B are installed, respectively.

Therefore, the L-side split combustion chamber 5A introduces the air-fuel mixture from the L-side intake port 9A through the L-side intake valve 11A, and ignites the air-fuel mixture by the L-side spark plug 15A to burn it. The generated waste gas is discharged from the L side exhaust port 10A via the L side exhaust valve 12A.
Similarly, the R-side split combustion chamber 5B introduces the air-fuel mixture from the R-side intake port 9B via the R-side intake valve 11B, ignites the introduced air-fuel mixture in the R-side ignition plug 15B, and burns it. The generated waste gas is discharged from the R side exhaust port 10B via the R side exhaust valve 12B. Since the pistons 2 are the same in the L-side split combustion chamber 5A and the R-side split combustion chamber 5B of the same cylinder, the same process is performed at the same time. For example, in the cylinder 3 having the cylinder number # 1 (see FIGS. 4 and 5), the L-side split combustion chamber 5A and the R-side split combustion chamber 5B are included.
At the same time, the intake process is performed at the same time, and then the compression process is performed at the same time.

As shown in FIG. 4, the L side intake port 9A and the R side intake port 9B of each cylinder 3 into which the air-fuel mixture is introduced are independent, and the L side intake manifold 16A and the R side intake manifold 16B are respectively provided at the respective ports. Connected. These L-side and R-side intake manifolds 16A and 16B
Is connected to the surge tank 17 to guide air from an air cleaner (not shown). L side intake manifold 16A
The L side throttle valve 18A and the L side fuel injector 19A are attached to the R side intake manifold 16B.
The side throttle valve 18B and the R side fuel injector 19B are installed, respectively.

By the fuel injection from the L-side fuel injector 19A and the R-side fuel injector 19B, the air-fuel mixture having a predetermined air-fuel ratio is supplied to each of the L-side split combustion chamber 5A and the R-side split combustion chamber 5B. The adjustment of the fuel injection amount from each of the L-side and R-side fuel injectors 19A and 19B is performed so that the air-fuel mixture supplied to one of the L-side split combustion chamber 5A or the R-side split combustion chamber 5B always has the stoichiometric air-fuel ratio, The air-fuel ratio of the air-fuel mixture supplied to the other is configured to change according to the engine load. Further, in the adjustment of the fuel injection amount, as shown in FIG. 5, the air-fuel mixture having the stoichiometric air-fuel ratio and the air-fuel mixture having the air-fuel ratio corresponding to the engine load are mixed in the L-side split combustion chamber 5A and the R-side split combustion chamber 5B. Is provided so as to be alternately changed for each intake process. The combustion order of each cylinder shown in FIG. 5 is # 1 → # 3 → # 4 → # 2.

Here, the air-fuel mixture having the air-fuel ratio corresponding to the engine load means the air-fuel mixture having the theoretical air-fuel ratio when the engine is heavily loaded, and the air-fuel mixture having a larger air-fuel ratio than the theoretical air-fuel ratio when the engine has a medium load. , A lean mixture with a larger air-fuel ratio at low engine load than at medium load, including the case of air only. In this way, the L-side split combustion chamber 5
One of the A-side and R-side split combustion chambers 5B performs normal combustion with a stoichiometric air-fuel mixture, and the other split combustion chamber performs lean burn with a lean air-fuel mixture according to the engine load. To be done. In particular, when the engine is under high load, the air-fuel mixture having the stoichiometric air-fuel ratio is supplied to both of the split combustion chambers 5A and 5B, and normal combustion is performed in both of the split combustion chambers 5A and 5B.

According to the above embodiment, the split combustion chambers 5A, 5
One of B, for example, the L-side split combustion chamber 5A is supplied with the stoichiometric air-fuel ratio, and the other split combustion chamber, for example, R-side split combustion chamber 5B is supplied with the air-fuel ratio of the air-fuel ratio according to the engine load. Therefore, when the engine has a low load or a medium load, a thin air-fuel mixture having a large air-fuel ratio is supplied to the other split combustion chamber, for example, the R-side split combustion chamber 5B. Therefore, when the engine has a low load / medium load, the lean burn is performed in one of the divided combustion chambers 5A and 5B, so that the fuel is saved and the fuel efficiency can be improved.

Further, in the above embodiment, even when lean burn is carried out in each of the split combustion chambers 5A or 5B of four cylinders, normal combustion is always performed in the other of the split combustion chambers 5A or 5B. After being carried out, all the cylinders are operated, and the valve operating device is always operating the four valves 11A, 11B, 12A, 12B for each cylinder as usual. As a result, there is no impact unlike the engine with a variable number of operating cylinders, the engine operates smoothly, and the riding feeling can be improved. Moreover, it is possible to prevent troubles such as carbon sticks caused by the valve operating mechanism being stopped for a long time.

Further, the divided combustion chambers 5A and 5B of the respective cylinders are constantly supplied with the air-fuel mixture having the stoichiometric air-fuel ratio and the air-fuel mixture having the air-fuel ratio which changes according to the engine load, alternately. It is possible to prevent only one side of the piston 2 of the cylinder and the combustion chamber 5 from becoming hot. As a result, the temperature in each cylinder is made uniform, thermal stress is reduced, and thermal deformation is prevented,
Sealing property can be secured and abnormal ignition can be prevented.

FIGS. 6, 7 and 8 are conceptual diagrams respectively showing the combustion chamber and the intake system of the second, third and fourth embodiments of the 4-cycle engine according to the present invention.

In the second embodiment shown in FIG. 6, the L-side intake manifold 20A and the R-side intake manifold 20B are merged on the upstream side, and the throttle valve 18 is provided for each cylinder.
It is one by one. In addition, in the third embodiment shown in FIG. 7, the throttle valve 18 of the second embodiment is not installed at the confluence of the L-side and R-side intake manifolds 20A and 20B, but is provided upstream of the surge tank 17 and the throttle valve is provided. 18 is common to each cylinder.

In the fourth embodiment shown in FIG. 8, the L-side and R-side intake manifolds 16A and 16B of the first embodiment shown in FIG.
Are connected to the L-side surge tank 17A and the R-side surge tank 17B, respectively.
An L side throttle valve 18A and an R side throttle valve 18B are installed on the upstream side of the R side surge tank 17B. In the above-described second to fourth embodiments, the number of throttle valves can be reduced and the cost can be reduced.

In each of the above embodiments, the L-side divided combustion chamber 5A or the R-side divided combustion chamber 5B is supplied to the divided combustion chamber in which the air-fuel ratio changes depending on the engine load. L side spark plug 15 depending on the concentration of
The ignition of the A and R side spark plugs 15B may be cut off. In each of the above embodiments, a carburetor may be used as the fuel supply device instead of the fuel injector. Further, the partition wall forming the L-side split combustion chamber 5A and the R-side split combustion chamber 5B may be formed only on the piston 2 side or only on the combustion chamber 5 side of the cylinder head 6.

[0025]

As described above, according to the four-cycle engine of the present invention, at least one of the cylinder block and the piston forming the combustion chamber has two intake valves and two exhaust valves arranged in the center thereof. A partition is formed at a position, the combustion chamber is divided into two, one of the divided combustion chambers is supplied with a stoichiometric air-fuel ratio mixture, and the other divided combustion chamber is supplied with the air-fuel ratio of the air-fuel ratio as an engine load. Since it is configured to be able to change according to the above, lean burn is possible while operating all the cylinders, so that it is possible to improve fuel economy while improving the riding feeling.

[Brief description of drawings]

FIG. 1 is a sectional view around an engine combustion chamber showing a first embodiment of a 4-cycle engine according to the present invention.

FIG. 2 is a view of the combustion chamber of FIG. 1 viewed from the piston side.

FIG. 3 is a sectional view taken along the line III-III in FIG.

4 is a schematic diagram showing a combustion chamber and an intake system of the engine of FIG.

5 is a diagram showing the relationship between the air-fuel mixture supplied to each of the divided combustion chambers in FIG. 1 and the steps of a 4-cycle engine.

FIG. 6 is a schematic diagram showing a relationship between an engine combustion chamber and an intake system in a second embodiment of a four-cycle engine according to the present invention.

FIG. 7 is a schematic diagram showing a relationship between an engine combustion chamber and an intake system in a third embodiment of a four-cycle engine according to the present invention.

FIG. 8 is a schematic diagram showing a relationship between an engine combustion chamber and an intake system in a fourth embodiment of a four-cycle engine according to the present invention.

[Explanation of symbols]

 1 Cylinder block 2 Piston 5 Combustion chamber 5A L-side split combustion chamber 5B R-side split combustion chamber 6 Cylinder head 9A L-side intake port 9B R-side intake port 11A L-side intake valve 11B R-side intake valve 12A L-side exhaust valve 12BR Side exhaust valve 13 Piston side bulkhead 14 Cylinder head side bulkhead 16A L side intake manifold 16B R side intake manifold 18A L side throttle valve 18B R side throttle valve 19A L side fuel injector 19B R side fuel injector

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[Procedure amendment]

[Submission date] July 6, 1992

[Procedure Amendment 1]

[Document name to be amended] Statement

[Name of item to be corrected] Claim 1

[Correction method] Change

[Correction content]

[Procedure Amendment 2]

[Document name to be amended] Statement

[Name of item to be corrected] 0002

[Correction method] Change

[Correction content]

[0002]

2. Description of the Related Art Among gasoline engines, an engine having a variable number of operating cylinders has been conventionally proposed for the purpose of improving fuel efficiency. For example, in the case of a four-cycle engine, this variable number-of-cylinders engine operates all four cylinders when the engine is fully loaded, but when the engine is partially loaded, for example, the valve operation of the valve operating device of two cylinders out of four cylinders is performed. Is stopped or the fuel supply is stopped to operate only two cylinders. In this way, by increasing or decreasing the number of operating cylinders, the fuel supply amount to the engine is saved and the fuel consumption is improved.

[Procedure 3]

[Document name to be amended] Statement

[Name of item to be corrected] 0003

[Correction method] Change

[Correction content]

[0003]

However, in the variable cylinder number engine as described above, the cylinder to be operated changes when the valve operation of the valve train is stopped or when the fuel supply is stopped, or when it is restarted or resupplied. Therefore, the impact at that time is large and the smooth riding feeling may be impaired.

[Procedure amendment 4]

[Document name to be amended] Statement

[Correction target item name] 0005

[Correction method] Change

[Correction content]

[0005]

According to the present invention, a combustion chamber is formed by a piston housed in a cylinder block and a cylinder head installed in the cylinder block.
In a four-cycle engine in which two intake valves and two exhaust valves are arranged in the combustion chamber, at least one of the cylinder head and the piston is provided with each of the two intake valves and exhaust valves. A partition wall is formed at a central position, the combustion chamber is divided into two, one of the divided combustion chambers is supplied with a mixture having a stoichiometric air-fuel ratio, and the other of the divided combustion chambers is supplied with an air-fuel ratio of an engine load. It is configured to be variable according to

[Procedure Amendment 5]

[Document name to be amended] Statement

[Name of item to be corrected] 0025

[Correction method] Change

[Correction content]

[0025]

As described above, according to the four-cycle engine of the present invention, at least one of the cylinder head and the piston forming the combustion chamber has two intake valves and two exhaust valves arranged in the center thereof. A partition is formed at a position, the combustion chamber is divided into two, one of the divided combustion chambers is supplied with a stoichiometric air-fuel ratio mixture, and the other of the divided combustion chambers is supplied with the air-fuel ratio of the air-fuel ratio as an engine load. Since it is configured to be able to change according to the above, lean burn is possible while operating all the cylinders, so that it is possible to improve fuel economy while improving the riding feeling.

─────────────────────────────────────────────────── ─── Continuation of the front page (51) Int.Cl. ⁵ Identification code Internal reference number FI Technical display location F02D 41/34 C 9039-3G F02M 69/00 360 G 9248-3G F02P 15/08 302 302 A 8923- 3G

Claims (1)

[Claims] 1. A four-cycle cycle in which a piston housed in a cylinder block and a cylinder head installed in the cylinder block form a combustion chamber, and two intake valves and two exhaust valves are arranged in the combustion chamber. In the engine, a partition wall is formed in at least one of the cylinder block and the piston at a central position where each of the two intake valves and the exhaust valves is arranged, and the combustion chamber is divided into two, and one of the two is divided. A four-cycle engine characterized in that an air-fuel mixture having a stoichiometric air-fuel ratio is supplied to a combustion chamber, and the air-fuel ratio of the air-fuel mixture supplied to the other split combustion chamber can be varied according to the engine load.