JPH05222934A - Four cycle engine - Google Patents

Abstract

PURPOSE:To improve fuel consumption by making lean burning possible while riding feeling is being made excellent, and also restrain the discharge quantity of nitrogen oxide. CONSTITUTION:A combustion chamber made up of a cylinder assembly housing a piston, and the piston, is divided into two. Mixture of a stoichiometric air-fuel ratio is supplied to one divided combustion chamber 5A, at the same time mixture containing exhaust gas is supplied to the other divided combustion chamber 5B, the air-fuel ratio of the mixture containing exhaust gas is changed according to an engine load, and at the same time the supply quantity of exhaust gas can also be changed according to the 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-mentioned circumstances, and it is possible to improve fuel economy by enabling lean burn while improving the ride feeling, and at the same time suppress the emission of nitrogen oxides. The object is to provide a possible 4-cycle engine.

[0005]

According to the present invention, a combustion chamber constituted by a cylinder assembly for accommodating a piston and the piston is divided into two, and one of the divided combustion chambers is supplied with a mixture having a stoichiometric air-fuel ratio. At the same time, the air-fuel mixture containing the exhaust gas is supplied to the other split combustion chamber, the air-fuel ratio of the air-fuel mixture containing the exhaust gas changes according to the engine load, and the supply amount of the exhaust gas also according to the engine load. It is configured to change.

[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.

Further, since the normal combustion is always carried out in the divided combustion chamber to which the stoichiometric air-fuel ratio is supplied, it means that all the cylinders are always operating. Therefore, there is no impact when the cylinder is reactivated after being deactivated like a variable cylinder number engine, and a smooth riding feeling can be realized.

Further, in the divided combustion chamber to which the exhaust gas is supplied, the amount of oxygen in the exhaust gas is small, so that even when lean burn is carried out in the divided combustion chamber, the ternary element for reducing nitrogen oxides is reduced. The reduction action of the catalyst is not hindered, and the emission of nitrogen oxides during lean burn can be suppressed.

Moreover, the exhaust gas is supplied at the maximum amount when the engine is under a low load and is not supplied when the engine is under a high load. Therefore, the amount of oxygen in the lean air-fuel mixture can be surely reduced, and therefore, the discharge of nitrogen oxides during lean burn can be surely suppressed.

[0010]

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

FIG. 1 is a schematic view showing a combustion chamber and an intake system of an engine showing a first embodiment of a four-cycle engine according to the present invention, and FIG. 2 is a sectional view around the combustion chamber of the engine shown in FIG. 3 is a view of the combustion chamber of FIG. 2 seen from the piston side, and FIG.
FIG. 4 is a sectional view taken along line IV-IV in FIG. 2.

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 which 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. The cylinder block 1, the cylinder head 6 and the head cover constitute a cylinder assembly. As shown in FIG. 3, the cylinder head 6 has L-side intake holes 7A and R for each combustion chamber 5 as shown in FIG.
The side intake hole 7B and the L side exhaust hole 8A and the R side exhaust hole 8B are opened. From these L side intake holes 7A and R side intake holes 7B, as shown in FIG.
The A and R side intake ports 9B respectively extend, and the L side exhaust holes 8A and R side exhaust holes 8B extend from the L side exhaust ports 10A and R.
Each side exhaust port 10B extends. These L-side exhaust port 10A and R-side exhaust port 10B are formed so as to join.

Further, as shown in FIG. 4, 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. 3, 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 shape 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 divided 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 FIG. 1), the suction process is performed simultaneously for both the L-side split combustion chamber 5A and the R-side split combustion chamber 5B, and then the compression process and the like are performed simultaneously.

The L side intake port 9A and the R side intake port 9B of each cylinder 3 for introducing the air-fuel mixture are independent as shown in FIG. 1, 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
L side throttle valve (primary throttle valve) 18A and L side fuel injector 19A
However, an R side throttle valve (secondary throttle valve) 18B and an R side fuel injector 19B are installed in the R side intake manifold 16B.

The L-side throttle valve 18A and the R-side throttle valve 18B are opened / closed by a link mechanism having an L-side valve lever 20A and an R-side valve lever 20B, as shown in FIGS. 3, 4 and 5.

That is, the L side valve lever 20A is connected to the L side throttle valve 18A via the valve rod 21, and the throttle cable 22 is connected. Therefore, the opening degree of the L-side throttle valve 18A is directly determined by the operation of the throttle cable 22, and is set to an opening degree proportional to the engine speed as shown by the solid line A in FIG. Therefore, the air amount proportional to the engine speed is supplied to the L-side split combustion chamber 5A.

Further, cam surfaces 23a and 23b are continuously formed on the L-side valve lever 20A as shown in FIG. Further, the R-side valve lever 20B is connected to the R-side throttle valve 18B via the valve rod 25, and the cam pin 24 is planted at the tip thereof. The cam pin 24 is provided so as to come into contact with the cam surfaces 23a and 23b of the L-side valve lever 20A. The R-side valve lever 20B is rotated in accordance with the engine speed of the L-side valve lever 20A, so that the cam pin 24 in the engine low load range.
Does not rotate against the cam surfaces 23a and 23b, so that the cam pin 24 does not rotate in the medium load range of the engine.
Then, the cam pin 24 contacts the cam surface 23b and further rotates in the high engine load range. Therefore, the R-side throttle valve 18B is fully closed in the engine low load range as shown by the chain line B in FIG.
The engine is gradually opened in the medium load range, and further opened and fully opened in the engine high load range. Therefore, R
The R-side throttle valve 18B is provided in the side split combustion chamber 5B.
The amount of air is supplied according to the opening degree of.

On the other hand, as shown in FIGS. 1 and 4, an EGR (exhaust gas circulation) port 26 is connected to the R side intake port 9B of each cylinder 3. This EGR port 26 is used for the R side fuel injector 1
The EGR pipe 27 is connected to the R-side intake port 9B on the downstream side of 9B and extends to the R-side intake manifold 16B. The other end of this EGR pipe 27 is L
The exhaust gas is connected to the merging portion of the R-side exhaust port 10A and the R-side exhaust port 10B, and exhaust gas is supplied to the R-side intake port 9A.
It is provided so that it can be supplied into B. Further, an EGR valve 28 is arranged on the EGR pipe 27. The EGR valve 28 is connected to a servomotor 30 via a valve rod 29. When the pressure difference between the L-side intake port 9A and the R-side intake port 9B is input as an electric signal, the servo motor 30 receives the EGR valve 28 based on this pressure difference.
Adjust the opening of.

That is, as shown by the chain double-dashed line C in FIG.
The opening degree of the EGR valve 28 is gradually increased in the engine low load range in which the R-side throttle valve 18B is fully closed,
The opening of the R-side throttle valve 18B is gradually reduced in the middle load range of the engine. R side throttle valve 1
The EGR valve 28 is fully closed in the engine high load range in which the valve 8B is further opened and is fully opened. Therefore, no air is supplied to the R-side split combustion chamber 5B in the low engine load region, only exhaust gas is supplied, air and exhaust gas are supplied in the medium engine load region, and only air in the high engine load region. Supplied.

Now, the L side fuel injector 19A and the R side fuel injector 1 shown in FIGS.
By injecting fuel from 9B, the L-side split combustion chamber 5A,
Air-fuel mixture having a predetermined air-fuel ratio is supplied to each of the R-side split combustion chambers 5B. That is, the L-side fuel injector 19
The fuel injection amount from A is adjusted so that the air-fuel mixture supplied to the L-side split combustion chamber 5A always has the stoichiometric air-fuel ratio,
In addition, the adjustment of the fuel injection amount from the R-side fuel injector 19B is configured such that the air-fuel ratio of the air-fuel mixture including the exhaust gas supplied to the R-side split combustion chamber changes according to the engine load.

Here, the air-fuel mixture containing the exhaust gas having the air-fuel ratio corresponding to the engine load means the air-fuel mixture having the stoichiometric air-fuel ratio when the engine is highly loaded, and the air-fuel ratio is larger and thinner than the stoichiometric air-fuel ratio when the engine is under medium load. The air-fuel mixture is a lean air-fuel mixture that has a larger air-fuel ratio when the engine load is low than when it is medium-load, and includes the case where only exhaust gas is used. Thus, normal combustion is performed in the L-side split combustion chamber 5A with a stoichiometric air-fuel mixture, and lean burn (lean burn) is performed in the R-side split combustion chamber 5B with a lean air-fuel mixture according to the engine load. To be done. However, when the engine load is high, the air-fuel mixture having the stoichiometric air-fuel ratio is also supplied to the R-side split combustion chamber 5B, so that the L-side and R-side split combustion chambers 5
Normal combustion is carried out in A and 5B. In addition,
The combustion order of the cylinder 3 shown in FIG. 1 is as follows: # 1 → # 3 → # 4 → #
The order is 2. A broken line D in FIG. 6 indicates the opening degree of the EGR valve which has been conventionally implemented.

According to the above embodiment, the L-side split combustion chamber 5A
To the R-side split combustion chamber 5B.
Since the air-fuel mixture having the air-fuel ratio corresponding to the engine load is supplied to the R side divided combustion chamber 5B, the air-fuel mixture having a large air-fuel ratio is supplied to the R-side split combustion chamber 5B when the engine has a low load or a medium load. Therefore, when the engine has a low load / medium load, lean burn is performed in the split combustion chamber 5B, so that fuel is saved and fuel economy can be improved.

Further, in the above embodiment, even when lean burn is carried out in each of the divided combustion chambers 5B of four cylinders, normal combustion is always carried out in the divided combustion chambers 5A, and eventually all the cylinders operate. In addition, the valve operating device always operates the four valves 11A, 11B, 12A, 12B for each cylinder as usual. As a result, there is no shock like the engine with variable number of operating cylinders, and smooth engine operation,
The ride 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, generally, when lean burn is carried out, the amount of oxygen in the air-fuel mixture increases, so that the nitrogen oxide reducing action of the three-way catalyst is hindered and the amount of nitrogen oxide NOx produced increases. .. In the first embodiment, the lean burn is executed because the EGR valve 28 is opened during the engine low / medium load operation to introduce the exhaust gas containing almost no oxygen into the R-side intake manifold 16B. Even so, since the amount of oxygen in the air-fuel mixture is small, it does not hinder the reduction action of nitrogen oxide NOx by the three-way catalyst,
As a result, the emission amount of nitrogen oxide NOx can be suppressed. In particular, nitrogen oxide NO during medium load operation where combustion temperature becomes high
The emission amount of x can be suppressed.

Further, since the exhaust gas supplied to the R-side split combustion chamber 5B has a lower density at high temperature than the atmosphere, it has a great effect of reducing pumping loss.

The R-side split combustion chamber 5B in which lean burn is performed has a lower combustion temperature than the L-side split combustion chamber 5A in which normal combustion is performed.
Since high-temperature (about 300 ° C.) exhaust gas is supplied to B, the combustion temperatures in both split combustion chambers 5A and 5B are substantially the same. Therefore, it is possible to prevent the temperature in each cylinder from becoming uniform and to prevent only one side from having a high temperature, reduce thermal stress and prevent thermal deformation, ensure sealing performance, and prevent abnormal ignition.

Since the EGR port 26 is connected to the R side intake port 9B at the downstream position of the R side fuel injector 19B, the R side throttle valve 18
B carbon stains, R side fuel injector 19B rubber or resins deteriorated by high temperature gas,
Further, it is possible to prevent deterioration and evaporation of the fuel inside the R-side fuel injector 19B.

Further, as shown in FIG. 4, a cooling layer 38 is provided between the EGR port 26 and the intake passage of the R-side intake manifold 16B, and cooling water or cooling air is introduced into the cooling layer 38. Therefore, the temperature of the R-side fuel injector 19B installed in the R-side intake manifold 16B can be prevented from increasing in temperature.

FIG. 7 is a diagram for explaining the operation of the valve lever in the second embodiment of the four-cycle engine according to the present invention. In the second embodiment, the same parts as those in the first embodiment are designated by the same reference numerals and the description thereof will be omitted.

In the second embodiment, the L side valve lever 3
The L side throttle valve 18A is connected to 1A, and the R side throttle valve 18B is connected to the R side valve lever 31B. The throttle cable 22 is connected to one end of the L-side valve lever 31A, and the cam roller 32 is installed at the other end. Further, the cam surface 33a is provided on the R side valve lever 31B.
And 33b are continuously formed. The L-side valve lever 31A is directly rotated by the operation of the throttle cable 22, and the cam roller 32 of the L-side valve lever 31A is rotated.
Is the cam surfaces 33a and 33b of the R-side valve lever 31B
The R-side valve lever 31B is rotated by abutting against.

The opening of the L-side throttle valve 18A is adjusted in proportion to the engine speed by the rotation of the L-side valve lever 31A by the operation of the throttle cable 22, as shown by the solid line A in FIG. .. Further, the R-side throttle valve 18B is fully closed when the engine has a low load, as shown by the chain line B in FIG. 6, and when the engine has a medium load, the cam roller 32 contacts the cam surface 33a and the R-side valve lever 31B rotates. And gradually opened. Further, when the engine load is high, the R-side throttle valve 18B is fully opened by the cam roller 32 contacting the cam surface 33b to rotate the R-side valve lever 31B and further opening operation. The EGR valve 28 includes the L-side throttle valve 18A and the R-side throttle valve 18 described above.
L side intake manifold 16A and R based on the opening degree of B
Corresponding to the pressure difference in the side intake manifold 16B, FIG.
The opening degree is adjusted as indicated by the two-dot chain line C.

Therefore, also in this second embodiment,
Similar to the first embodiment, the ride feeling can be improved and the lean burn can be performed to improve the fuel consumption, and the emission of nitrogen oxides can be suppressed. Has a great effect.

FIG. 8 is an explanatory view of the operation of the valve lever in the third embodiment of the four-cycle engine according to the present invention. The same parts as those in the first embodiment are designated by the same reference numerals and the description thereof will be omitted. To do.

In the third embodiment, the L side valve lever 3
4A is connected to the L side throttle valve 18A, and R side valve lever 34B is connected to the R side throttle valve 18B. The throttle cable 22 is connected to the L-side valve lever 34A, and the L-side valve lever 34A is directly rotated by operating the throttle cable 22. The R-side valve lever 34B is operatively connected to the L-side valve lever 34A via the idle lever 35 and the connecting rod 36. That is, the idle lever 35 is provided rotatably coaxially with the L-side valve lever 34A, and the connecting rod 36 is provided with the R-side valve lever 34B and the idle lever 35.
Connect the both ends of and. A locking plate 37 is fixed to the idle lever 35, and when the L-side valve lever 34A is locked to the locking plate 37, the idle lever 35 rotates synchronously with the L-side valve lever 34A.

The L side throttle valve 18A is based on the rotation of the L side valve lever 34A by the operation of the throttle cable 22, and the solid line in FIGS. 8 (A), (B), (C) and (D) and FIG. As shown in A, the opening operation is performed in proportion to the engine speed. Further, when the engine load is low, the R-side throttle valve 18B is in a fully closed state without rotating the R-side valve lever 43B as shown in FIGS. 8 (A) and 8 (B). ′) When the engine has a medium load, as shown in FIGS. 8B and 8C,
The R-side valve lever 34B rotates to gradually open the R-side throttle valve 18B. When the engine has a high load, the R-side valve lever 34B rotates as shown in FIGS. 8C and 8D, and the R-side throttle valve 18B is further operated to be fully closed.

In the third embodiment, the L-side throttle valve 18A, the R-side throttle valve 18B and the EGR valve 28 have the same characteristics as the valve opening characteristics shown in FIG. 6, but the characteristics of the R-side throttle valve 18B. As shown by the one-dot chain line B'in FIG. 9, the valve opening of the L-side throttle valve 18A shown by the solid line A is exceeded when the engine has a high load. However, there is no practical problem, and the cost can be reduced as compared with the case of the L-side valve lever 20A and the R-side valve lever 20B of the first embodiment. Other,
Also in the third embodiment, the same effect as that of the first embodiment can be obtained.

FIGS. 10, 11 and 12 are conceptual diagrams showing the combustion chamber and the intake system of the fourth, fifth and sixth embodiments of the 4-cycle engine according to the present invention, respectively.

In the fourth embodiment shown in FIG. 10, the L-side intake manifold 38A and the R-side intake manifold 38B are joined on the upstream side, and the throttle valve 18 is joined to this joining portion.
Is installed and one throttle valve 18 is provided for each cylinder. Further, in the fifth embodiment shown in FIG. 11, the throttle valve 18 of the fourth embodiment is set to the L side and the R side.
The throttle valve 18 is provided in the upstream side of the surge tank 17 instead of being installed at the confluence portion of the side intake manifolds 38A and 38B, and the throttle valve 18 is made common to each cylinder. These fourth
In the fifth embodiment, the distance m ₁ from the center of the cylinder 3 to the tip of the EGR port 26, and the intake manifold 2
By selecting the distance m ₂ to the merging portion of 2A and 22B, the exhaust gas is changed to the intake manifold 22A.
It can be prevented from wrapping around inside.

In the sixth embodiment shown in FIG. 12, the L side intake manifold 16A of the first embodiment shown in FIG. 1 is connected to the L side surge tank 17A, and the R side intake manifold 16B is connected to the R side surge tank 17B. However, the L side surge tank 17A and the R side surge tank 17B have L
Side throttle valve 18A, R side throttle valve 18
B are installed respectively. Further, in the sixth embodiment, the L-side EGR pipe 3 that guides the exhaust gas is provided.
9A and R side EGR pipe 39B are installed, and R side EGR pipe is installed.
Exhaust gas is supplied from the pipe 39B to the R-side intake port 9B of each cylinder 3 via the large-diameter R-side EGR port 40B as in the first to fifth embodiments. Furthermore, L side E
Also from the GR pipe 39A, the L side intake port 9A of each cylinder 3
Exhaust gas is supplied via the small-diameter L-side EGR port 40A. At this time, the L side EGR pipe 39
The L side EGR valve 41 is connected to the A and R side EGR pipes 39B.
The A and R side EGR valves 41B are installed respectively. R
The side EGR valve 41B operates in the same manner as the EGR valve 28 of the first to fifth embodiments, and the L side EGR valve 41A is fully closed at high load and is slightly opened at low and medium loads. L
The reason why the side EGR valve 24A is slightly opened at the time of low / medium load is to reduce the combustion temperature in the divided combustion chamber 5A and suppress the emission of nitrogen oxides.

FIG. 13 is a conceptual diagram showing a combustion chamber and an intake system showing a seventh embodiment of a four-cycle engine according to the present invention. In the seventh embodiment, the same parts as those in the first and sixth embodiments are designated by the same reference numerals and the description thereof will be omitted.

As shown in FIGS. 13 and 14, four cylinders 3 are formed in series in a cylinder block 1 installed in a crankcase 40, and a piston 41 is provided in each cylinder 3.
Is housed. The piston 41 is connected to the crankshaft 42 via the connecting rod 4, and the crankshaft 42 is rotatably supported in the crankcase 40. The cylinder block 1 includes a cylinder head 4
3, a head cover (not shown) are sequentially installed, and the cylinder block 1, the cylinder head 43, and the head cover constitute a cylinder assembly.

The pistons 41 are attached to the cylinder head 43.
Combustion chambers (44A, 44B) are formed between and, and adjacent combustion chambers are connected via a connecting portion 44C. One of the adjacent combustion chambers is the L-side split combustion chamber 44A, and the other combustion chamber is the R-side split combustion chamber 44B. L side split combustion chamber 4
4A has an L side intake valve 45A and an L side exhaust valve 46
Two A's are arranged, and two R-side intake valves 45B and two R-side intake valves 46B are also arranged in the R-side split combustion chamber 44B. L-side and R-side exhaust ports 47A and 47B are connected to exhaust holes (not shown) in which the L-side and R-side exhaust valves 46A and 46B are arranged, respectively. These L-side and R-side exhaust ports 47A and 47B are joined in the exhaust manifold 48.

L-side and R-side intake ports 49A and 49B, which join, are respectively connected to intake holes (not shown) in which the L-side and R-side intake valves 45A and 45B are arranged. The L-side and R-side intake manifolds 50A and 50B are connected to the side intake ports 49A and 49B, respectively.
The L-side intake manifold 50A includes the L-side surge tank 17
R side intake manifold 50B is connected to R side surge tank 17B, and L side throttle valve 1 is connected.
Air is supplied into the L-side split combustion chamber 44A and the R-side split combustion chamber 44B by the opening operations of the 8A and R-side throttle valves 18B, respectively. Further, an L-side fuel injector 19A and an R-side fuel injector 19B are installed in the L-side intake manifold 50A and the R-side intake manifold 50B, respectively. Furthermore, the R-side intake port 49B has an EGR pipe 27 and an EGR port 26.
Exhaust gas is supplied by opening the EGR valve 28 via.

Here, the EGR port 26 is the R-side fuel injector 19B at the R-side intake port 49B.
Is connected to the downstream side of. Further, the opening / closing operation of the L-side throttle valve 18A, the R-side throttle valve 18B and the EGR valve 28 is operated as shown in FIG. 6 using the link mechanism of the first embodiment or the second embodiment, or the third operation. It operates as shown in FIG. 9 using the link mechanism of the embodiment. Therefore, the L-side split combustion chamber 44A is supplied with an amount of air proportional to the engine speed, and the R-side split combustion chamber 44B receives only exhaust gas at low engine load and exhaust gas and air at medium engine load. When loaded, only air is supplied.

Further, the L side fuel injector 19
The fuel injection amount of A is adjusted so that the air-fuel mixture supplied to the L-side split combustion chamber 44A has a stoichiometric air-fuel ratio. Also, R
The side fuel injector 19B is connected to the R side split combustion chamber 4
The air-fuel mixture containing exhaust gas supplied to 4B becomes a stoichiometric air-fuel mixture at high engine load, becomes a lean air-fuel ratio larger than the stoichiometric air-fuel ratio at medium engine load, and further becomes air-fuel ratio at low engine load. The fuel injection amount is adjusted so that a large lean mixture is obtained.

Further, in the cylinder head 43, the L-side split combustion chamber 44A, the R-side split combustion chamber 44B and the connecting portion 44 are provided.
Spark plugs 51A, 51B and 51C are installed at positions facing C respectively. These spark plugs 51A,
51B and 51C are ignited at the same time, and two adjacent L-side split combustion chambers 44A and R-side split combustion chambers 44B are formed.
The two pistons 41 operate synchronously. Therefore, the adjacent cylinders 3 forming the L-side split combustion chamber 44A and the R-side split combustion chamber 44B simultaneously perform the steps of intake, compression, explosion and exhaust.

Also in the seventh embodiment, lean burn is carried out in the R-side split combustion chamber 44B, so that the fuel consumption can be improved and the R-side split combustion chamber 44B is improved.
Since exhaust gas can be supplied to the
It is possible to suppress the emission amount of nitrogen oxide NOx during implementation of lean burn. Furthermore, since the two pistons 41 that respectively configure the L-side split combustion chamber 44A and the R-side split combustion chamber 44B operate in synchronism, the engine operates smoothly and the riding comfort can be improved. Besides, in the seventh embodiment, the same effect as that of the first embodiment can be obtained.

In each of the above-mentioned embodiments, in the divided combustion chambers 5B and 44B to which the air-fuel ratio whose air-fuel ratio changes according to the engine load is supplied, depending on the concentration of the air-fuel mixture, for example, only the exhaust gas when the engine has a low load When R is supplied, the ignition of the R side spark plugs 15B and 51B 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. Furthermore, L-side split combustion chamber 5A
The partition wall forming the R-side divided 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.

[0053]

As described above, according to the four-cycle engine of the present invention, the combustion chamber formed by the cylinder assembly for accommodating the piston and the piston is two.
The air-fuel ratio of the air-fuel mixture is divided into two, and one of the divided combustion chambers is supplied with a stoichiometric air-fuel ratio, and the other of the divided combustion chambers is supplied with an air-fuel mixture containing exhaust gas. The exhaust gas supply amount can be changed according to the engine load as well, so that all cylinders are operated to improve the ride feeling while enabling lean burn and fuel consumption. Can be reduced, and at the same time, the exhaust amount of nitrogen oxides can be suppressed by supplying the exhaust gas.

[Brief description of drawings]

FIG. 1 is a schematic diagram showing a combustion chamber and an intake system of an engine in a first embodiment of a four-cycle engine according to the present invention.

2 is a cross-sectional view around a combustion chamber of the 4-cycle engine shown in FIG.

FIG. 3 is a view of the combustion chamber of FIG. 2 viewed from the piston side.

FIG. 4 is a sectional view taken along line IV-IV in FIG.

FIG. 5 is an operation explanatory view of the valve lever shown in FIG.

FIG. 6 is a graph showing opening characteristics of the throttle valve and EGR valve of FIG.

FIG. 7 is an operation explanatory view of the valve lever in the second embodiment of the four-cycle engine according to the present invention.

8 (A), (B), (C) and (D) are operation explanatory views of the valve lever in the third embodiment of the four-cycle engine according to the present invention.

9 is a valve characteristic diagram of the throttle valve and the EGR valve shown in FIG.

FIG. 10 is a schematic diagram showing a relationship between a combustion chamber of an engine and an intake system in a fourth embodiment of a four-cycle engine according to the present invention.

FIG. 11 is a schematic diagram showing a relationship between an engine combustion chamber and an intake system in a fifth embodiment of a four-cycle engine according to the present invention.

FIG. 12 is a schematic diagram showing a relationship between an engine combustion chamber and an intake system in a sixth embodiment of a four-cycle engine according to the present invention.

FIG. 13 is a schematic diagram showing a relationship between a combustion chamber of an engine and an intake system in a seventh embodiment of a four-cycle engine according to the present invention.

14 is a sectional view taken along line XIV-XIV in FIG.

[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 13 Piston Side Partition 14 Cylinder Head Side Partition 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 20A L side valve lever 20B R side valve lever 22 Throttle cable 24 Cam pin 26 EGR port 27 EGR pipe 28 EGR valve 41 Piston 44A L Side division combustion chamber 44B R Side division material combustion chamber 44C Connection part

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[Procedure amendment]

[Submission date] July 6, 1992

[Procedure Amendment 1]

[Document name to be amended] Statement

[Correction target item name] 0009

[Correction method] Change

[Correction content]

Moreover, the exhaust gas is supplied at the maximum amount when the engine load is low and is not supplied at the time when the engine load is high, so that the lean air-fuel mixture has a large air-fuel ratio. Therefore, the amount of oxygen in the lean air-fuel mixture can be surely reduced, and therefore, the discharge of nitrogen oxides during lean burn can be surely suppressed.

[Procedure Amendment 2]

[Document name to be amended] Statement

[Correction target item name] 0014

[Correction method] Change

[Correction content]

Further, as shown in FIG. 4, 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 exhaust gas from the combustion chamber 5.

[Procedure 3]

[Document name to be amended] Statement

[Correction target item name] 0017

[Correction method] Change

[Correction content]

Therefore, the L-side divided combustion chamber 5A introduces the air-fuel mixture from the L-side intake port 9A via the L-side intake valve 11A, and ignites the air-fuel mixture by the L-side ignition plug 15A to burn it. The generated exhaust 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 produced exhaust 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 FIG. 1), the suction process is performed simultaneously for both the L-side split combustion chamber 5A and the R-side split combustion chamber 5B, and then the compression process and the like are performed simultaneously.

[Procedure amendment 4]

[Document name to be amended] Statement

[Correction target item name] 0021

[Correction method] Change

[Correction content]

Further, cam surfaces 23a and 23b are continuously formed on the L-side valve lever 20A as shown in FIG. Further, the R-side valve lever 20B is connected to the R-side throttle valve 18B via the valve rod 25, and the cam pin 24 is planted at the tip thereof. The cam pin 24 is provided so as to come into contact with the cam surfaces 23a and 23b of the L-side valve lever 20A. The R-side valve lever 20B is rotated in accordance with the engine speed of the L-side valve lever 20A, so that the cam pin 24 in the engine low load range.
Does not rotate against the cam surfaces 23a and 23b, so that the cam pin 24 does not rotate in the medium load range of the engine.
The cam pin 24 abuts on the cam surface 23b in the high engine load range and abuts on the L side valve lever 20.
It rotates synchronously with A. Therefore, the R-side throttle valve 18B is fully closed in the low engine load range, gradually opened in the medium engine load range, and further opened in the high engine load range, as shown by the chain line B in FIG. Is fully opened. Therefore, the amount of air corresponding to the opening of the R-side throttle valve 18B is supplied to the R-side split combustion chamber 5B.

[Procedure Amendment 5]

[Document name to be amended] Statement

[Name of item to be corrected] 0022

[Correction method] Change

[Correction content]

On the other hand, as shown in FIGS. 1 and 4, an EGR (exhaust gas recirculation) port 26 is connected to the R side intake port 9B of each cylinder 3.
The EGR port 26 communicates with the R-side intake port 9B on the downstream side of the R-side fuel injector 19B, extends to the R-side intake manifold 16B, and is connected to the EGR pipe 27. The other end of this EGR pipe 27 is L
The exhaust gas is connected to the merging portion of the R-side exhaust port 10A and the R-side exhaust port 10B, and exhaust gas is supplied to the R-side intake port 9A.
It is provided so that it can be supplied into B. Further, an EGR valve 28 is arranged on the EGR pipe 27. The EGR valve 28 is connected to a servomotor 30 via a valve rod 29. When the pressure difference between the L-side intake port 9A and the R-side intake port 9B is input as an electric signal, the servo motor 30 receives the EGR valve 28 based on this pressure difference.
Adjust the opening of.

[Procedure correction 6]

[Document name to be amended] Statement

[Name of item to be corrected] 0023

[Correction method] Change

[Correction content]

That is, as shown by the chain double-dashed line C in FIG.
The opening degree of the EGR valve 28 is gradually increased in the engine low load range in which the R-side throttle valve 18B is fully closed,
The opening of the R-side throttle valve 18B is gradually reduced in the middle-load range of the engine in which it opens suddenly. R side throttle valve 1
The EGR valve 28 is fully closed in the engine high load range in which the valve 8B is further opened and is fully opened. Therefore, no air is supplied to the R-side split combustion chamber 5B in the low engine load region, only exhaust gas is supplied, air and exhaust gas are supplied in the medium engine load region, and only air in the high engine load region. Supplied.

[Procedure Amendment 7]

[Document name to be amended] Statement

[Correction target item name] 0028

[Correction method] Change

[Correction content]

Further, in general, when lean burn is carried out, the combustion gas contains a large amount of oxygen, so that the nitrogen oxide reducing action of the three-way catalyst is obstructed and the emission amount of nitrogen oxide NOx increases. .. In this first embodiment, the EGR valve 28 is opened during operation of the engine at low / medium load, and R
Since the exhaust gas containing almost no oxygen is introduced into the side intake manifold 16B, the amount of oxygen in the air-fuel mixture is small even if lean burn is performed, so that the three-way catalyst reduces NOx in the nitrogen oxides. As a result, the emission amount of nitrogen oxide NOx can be suppressed. In particular, it is possible to suppress the emission of nitrogen oxides NOx during medium load operation where the combustion temperature becomes high.

[Procedure Amendment 8]

[Document name to be amended] Statement

[Correction target item name] 0035

[Correction method] Change

[Correction content]

The opening of the L-side throttle valve 18A is adjusted in proportion to the engine speed by the rotation of the L-side valve lever 31A by the operation of the throttle cable 22, as shown by the solid line A in FIG. .. Further, the R-side throttle valve 18B is fully closed when the engine has a low load, as shown by the chain line B in FIG. 6, and when the engine has a medium load, the cam roller 32 contacts the cam surface 33a and the R-side valve lever 31B rotates. Then, the opening operation is suddenly performed. Further, in the R-side throttle valve 18B, when the engine has a high load, the cam roller 32 comes into contact with the cam surface 33b to rotate the R-side valve lever 31B, and the L-side throttle valve 1B is rotated.
8A is synchronized with the opening operation, resulting in a fully open state. EG
The R valve 28 is an L side intake manifold 16A and an R side intake manifold 16B based on the opening degrees of the L side throttle valve 18A and the R side throttle valve 18B.
The opening degree is adjusted as indicated by the chain double-dashed line C in FIG. 6 according to the internal pressure difference.

[Procedure Amendment 9]

[Document name to be amended] Statement

[Correction target item name] 0039

[Correction method] Change

[Correction content]

The L side throttle valve 18A is based on the rotation of the L side valve lever 34A by the operation of the throttle cable 22, and the solid line in FIGS. 8 (A), (B), (C) and (D) and FIG. As shown in A, the opening operation is performed in proportion to the engine speed. Further, when the engine load is low, the R-side throttle valve 18B is in a fully closed state without rotating the R-side valve lever 43B as shown in FIGS. 8 (A) and 8 (B). ′) When the engine has a medium load, as shown in FIGS. 8B and 8C,
The R-side valve lever 34B rotates, and the R-side throttle valve 18B is rapidly opened. When the engine has a high load, as shown in FIGS. 8C and 8D, the R-side valve lever 34B is rotated, and the R-side throttle valve 18B is operated to open in synchronization with the L-side throttle valve 18A to be in a fully opened state.

[Procedure Amendment 10]

[Document name to be amended] Statement

[Correction target item name] 0042

[Correction method] Change

[Correction content]

In the fourth embodiment shown in FIG. 10, the L-side intake manifold 38A and the R-side intake manifold 38B are joined on the upstream side, and the throttle valve 18 is joined to this joining portion.
Is installed and one throttle valve 18 is provided for each cylinder. Further, in the fifth embodiment shown in FIG. 11, the throttle valve 18 of the fourth embodiment is set to the L side and the R side.
The throttle valve 18 is provided in the upstream side of the surge tank 17 instead of being installed at the confluence portion of the side intake manifolds 38A and 38B, and the throttle valve 18 is made common to each cylinder. These fourth
In addition, in the fifth embodiment, the distance m ₁ from the center of the cylinder 3 to the tip of the EGR port 26, and the intake manifold 3
By selecting the distance m ₂ to the merging portion of 8A and 38B, the exhaust gas is changed to the intake manifold 38A.
It can be prevented from wrapping around inside.

[Procedure Amendment 11]

[Document name to be corrected] Drawing

[Name of item to be corrected] Figure 3

[Correction method] Change

[Correction content]

[Figure 3]

[Procedure Amendment 12]

[Document name to be corrected] Drawing

[Name of item to be corrected] Fig. 4

[Correction method] Change

[Correction content]

[Figure 4]

[Procedure Amendment 13]

[Document name to be corrected] Drawing

[Name of item to be corrected] Figure 5

[Correction method] Change

[Correction content]

[Figure 5]

[Procedure Amendment 14]

[Document name to be corrected] Drawing

[Correction target item name] Figure 8

[Correction method] Change

[Correction content]

[Figure 8]

[Procedure Amendment 15]

[Document name to be corrected] Drawing

[Name of item to be corrected] Fig. 13

[Correction method] Change

[Correction content]

[Fig. 13]

Continuation of the front page (51) Int.Cl. ⁵ Identification code Internal reference number FI Technical display location F02M 25/07 550 G 8923-3G R 8923-3G 580 B 8923-3G (72) Inventor Chiaki Hirata Hamamatsu, Shizuoka Prefecture 300, Takatsuka-cho, Ichi, Japan Suzuki Stock Company (72) Inventor, Kunaki Ishibe 300, Takatsuka-cho, Hamamatsu City, Shizuoka Prefecture Suzuki Stock Company

Claims (4)

[Claims] 1. A combustion chamber constituted by a cylinder assembly for accommodating a piston and the piston is divided into two, and 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. A mixture containing exhaust gas is supplied, and the air-fuel ratio of the mixture containing exhaust gas changes according to the engine load,
A four-cycle engine characterized in that the supply amount of the exhaust gas can be changed according to the engine load. 2. The four-cycle engine according to claim 1, wherein the divided combustion chamber is constituted by dividing one combustion chamber constituted by one piston and a cylinder assembly for accommodating the piston. 3. The cylinder according to claim 1, wherein each of the divided combustion chambers is configured to be adjacent to each other by a cylinder assembly accommodating one piston adjacently and each piston.
Cycle engine. 4. The exhaust gas injection position is set on the downstream side of the fuel injection in the intake passage connected to the other split combustion chamber.
Cycle engine.