JPH0828323A - Air-fuel ratio control device for engine - Google Patents

Abstract

PURPOSE:To effectively attain improvement of engine performance and suppress excessive consumption of fuel by accurately adjusting an air-fuel ratio of air-fuel mixture to be supplied to a cylinder based on detection of property of exhaust by means of an exhaust sensor. CONSTITUTION:An exhaust sensor 91 is arranged for detecting property of exhaust 100 generated by combustion inside a cylinder. An air-fuel ratio of air-fuel mixture intaken in the cylinder is adjusted based on the detection signal of the exhaust sensor 91. A guide passage 115 is formed for guiding the exhaust 100 outside a system, while an accumulator chamber 119 communicated with the guide passage 115 is formed. The property of the exhaust 100 in the accumulator chamber 119 is detected by the exhaust sensor 91. A throttle 131 is provided on one division end 122 of the guide passage 115 to the accumulator chamber 119.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an engine used for ships, motorcycles, automobiles and the like. More specifically, an exhaust sensor for detecting the property of exhaust gas is provided, and a cylinder is detected by a detection signal of the exhaust sensor. The present invention relates to an engine air-fuel ratio control device that adjusts the air-fuel ratio of an air-fuel mixture sucked into the engine.

[0002]

2. Description of the Related Art Conventionally, some engines mounted on automobiles are constructed as follows.

That is, a mixture of air and fuel is appropriately supplied to the cylinder, and this mixture is burned in the cylinder. By this combustion, burnt gas is generated, and exhaust gas containing this burned gas is discharged from the inside of the cylinder.

An exhaust sensor for detecting the properties of the exhaust gas is provided. Then, the air-fuel ratio (A / F) of the air-fuel mixture is adjusted to a desired value by the detection signal of this exhaust sensor, whereby the performance of the engine and the wasteful consumption of fuel are suppressed. ing.

[0005]

By the way, when the engine is a two-cycle engine, a fresh air blow-through phenomenon occurs in the scavenging process, and in the exhaust gas, in addition to the burned gas, a new air flow is generated. O ₂ components in the air are mixed.

[0006] Then, for the amount of the O ₂ component, which may reach about 100 times the O ₂ component of burned gas produced by combustion in the cylinder.

Therefore, in the above-mentioned conventional structure, even if the property of the exhaust gas is detected, the property of the burnt gas cannot be accurately grasped by this, that is, the mixture gas supplied into the cylinder is not detected. The air-fuel ratio cannot be accurately grasped.

Therefore, in the above-mentioned conventional configuration, it is not possible to accurately adjust the air-fuel ratio to a desired value based on the detection of the property of the exhaust gas. As a result, the engine performance is improved and the wasteful consumption of fuel is suppressed. However, there is a disadvantage that it cannot be achieved sufficiently.

On the other hand, in order to lubricate the engine, normally, the lubricating oil is supplied together with the air-fuel mixture into the cylinder. In this case, a part of the lubricating oil which is unburned oil after lubricating the cylinder passes through the guide passage. There is a risk that this lubricating oil will flow through the pressure accumulating chamber and adhere to the sensor element portion of the exhaust sensor. Then, if the lubricating oil adheres to the sensor element in this manner, the detection accuracy and detection responsiveness of the exhaust sensor decrease, and
This exhaust sensor is deteriorated at an early stage and causes a problem in life.

[0010]

SUMMARY OF THE INVENTION The present invention has been made in view of the above circumstances, and more accurately requests the air-fuel ratio of the air-fuel mixture to be supplied into the cylinder based on the detection of the property of the exhaust gas by the exhaust gas sensor. The object is to improve the engine performance and suppress wasteful consumption of fuel more effectively by adjusting the value.

Further, the lubricating oil discharged from the cylinder together with the exhaust gas is prevented from adhering to the sensor element portion of the exhaust gas sensor to improve the detection accuracy and detection responsiveness of the exhaust gas sensor, The purpose is to improve the life.

[0012]

[Means for Solving the Problems] The present invention for achieving the above object is as follows.

Incidentally, this "means for solving the problem"
In the section, the terms in parentheses below correspond to the terms in the claims.

The engine air-fuel ratio control system of the present invention comprises:
An exhaust sensor 91 for detecting the properties of the exhaust gas 100 generated by the combustion in the cylinders 16-18 is provided, and the air-fuel ratio of the air-fuel mixture 99 sucked into the cylinders 16-18 is adjusted by the detection signal of the exhaust sensor 91. And a guide passage 115 for guiding the exhaust 100 to the outside of the system is provided,
A pressure accumulating chamber 119 communicating with the guide passage 115 is provided, and the property of the exhaust gas 100 in the pressure accumulating chamber 119 is determined by the exhaust gas sensor 9 described above.
1, the throttle portion 131 is provided at one divided end (inlet) 122 of the guide passage 115 to the pressure accumulating chamber 119.

In the above case, the throttle portion (drain hole) 131 may be formed on the bottom surface 132 of the pressure accumulating chamber 119.

Further, at least a part of the bottom surface 132 of the pressure accumulating chamber 119 may be inclined so as to face downward as it faces the throttle portion (drain hole) 131.

[0017]

[Operation] The operation of the above configuration is as follows.

In the "action" section, the terms in parentheses below correspond to the terms in the claims.

Exhaust sensor 9 for detecting the properties of exhaust 100
In the case where the air-fuel ratio of the air-fuel mixture 99 sucked into the cylinders 16 to 18 is adjusted by the detection signal of 1,
A guide passage 115 for guiding the exhaust 100 to the outside of the system is provided, a pressure accumulating chamber 119 communicating with the guide passage 115 is provided, and the property of the exhaust 100 in the pressure accumulating chamber 119 is detected by the exhaust sensor 91.

Therefore, when the exhaust gas 100 having a high pressure flows into the pressure accumulating chamber 119 through the guide passage 115, the large pressure of the exhaust gas 100 is temporarily accumulated in the pressure accumulating chamber 119. Therefore, immediately after this, even if the exhaust gas 100 having a low pressure tries to flow into the pressure accumulating chamber 119, this flow is blocked. Then, the property of the exhaust gas 100 having a large pressure is detected by the exhaust gas sensor 91.

By the way, particularly the two-cycle engine 10
Then, the pressure in the cylinders 16 to 18 becomes the maximum pressure in the "explosion process", and the pressure is gradually reduced as the "scavenging process" is started.

In the "explosion process", the cylinders 16 to 1
Most of the exhaust gas 100 to be discharged from the inside of the cylinder 8 is composed of burnt gas, and the cylinders 16 to 18 are almost filled with burned gas at the maximum pressure.

On the other hand, in the "scavenging process", the exhaust 100 is discharged from the inside of the cylinders 16 to 18 into the exhaust passages 43 and 4.
It is discharged into 7,48, but immediately after this discharge,
The pressure inside the exhaust passages 43, 47, 48 becomes maximum, and the pressure gradually decreases as the scavenging progresses.

Then, the exhaust 100 passes through the exhaust passage 43,
Immediately after being discharged into the exhaust passages 47, 48, the scavenging has just started, and the amount of fresh air blown into the exhaust passages 43, 47, 48 is small.
Most of the exhaust gas 100 in 47, 48 is composed of burnt gas, that is, the exhaust passages 43, 47, 48 are almost filled with burned gas at the maximum pressure.

Therefore, in the cylinders 16 to 18 and the exhaust passage 4
Most of the exhaust 100 that produces the maximum pressure in the exhaust system such as 3, 47, 48 is composed of burnt gas, and the exhaust 100 having a high pressure is used in the guide passage 11
When the gas flows into the pressure accumulating chamber 119 through No. 5, the exhaust gas 100
Most of them are burnt gas.

As described above, once the exhaust gas 100 having a large pressure is stored in the pressure accumulating chamber 119, immediately after that, the fresh air mixture 99 containing a large amount of O ₂ component flows into the pressure accumulating chamber 119. Attempts to prevent this inflow will this be due to the low pressure. Therefore, as described above, the properties of the exhaust 100, which is mostly burned gas, are detected by the exhaust sensor 91.

Therefore, based on the detection by the exhaust sensor 91, the air-fuel ratio of the air-fuel mixture 99 at that time can be accurately grasped, and according to this, the subsequent air-fuel ratio can be adjusted to a desired value more accurately. You can

Further, in particular, as shown in FIG. 1, one dividing end (inflow port) of the guide passage 115 to the pressure accumulating chamber 119.
A diaphragm 131 is provided at 122.

For this reason, the exhaust 100 discharged from the "inside of the cylinder" and flowing through the guide passage 115, and the cylinders 16-18.
The fine particles of the lubricating oil, which is unburned oil and has been discharged from the “in-cylinder” after lubricating the oil, tries to flow from the portion having a large cross-sectional area of the guide passage 115 toward the portion having a small cross-sectional area in the throttle portion 131. When doing so, the direction of the flow is suddenly changed (arrow G in FIG. 1).

At this time, since the exhaust gas 100 has a small inertial force, its flow can be suddenly changed and smoothly flows into the pressure accumulating chamber 119 through the throttle portion 131. However, since the fine particles of the lubricating oil have a large inertial force, the flow cannot be suddenly changed, and a part of them cannot be changed in the guide passage 115.
It collides with the inner surface of and is attached to this inner surface. Then, the flow of the lubricating oil is weakened and the throttle portion 1
The passage of 31 will be suppressed.

Therefore, the amount of the lubricating oil flowing into the pressure accumulating chamber 119 is reduced, so that the lubricating oil is suppressed from adhering to the sensor element portion 106 of the exhaust sensor 91.

In the above case, the throttle portion (drain hole) 131 may be formed on the bottom surface 132 of the pressure accumulating chamber 119.

In this way, the bottom surface 1 of the pressure accumulating chamber 119 is
When the lubricating oil is accumulated on 32, the lubricating oil is discharged from the pressure accumulating chamber 119 through the throttle portion (drain hole) 131.

Further, at least a part of the bottom surface 132 of the pressure accumulating chamber 119 may be inclined downward so as to face the throttle portion (drain hole) 131.

In this way, the bottom surface 1 of the pressure accumulating chamber 119 is
The lubricating oil that tries to collect on 32 flows smoothly on the inclined surface 132a toward the throttle portion (drain hole) 131 due to its own weight, and as described above, the throttle portion (drain hole) 1
It is discharged from the pressure accumulating chamber 119 through 31.

[0036]

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

(Example 1)

1 to 10 show the first embodiment.

In FIG. 2, reference numeral 1 is a ship as an example of a vehicle, and an arrow Fr indicates the forward direction of the ship 1. The right and left described below means the direction toward the front.

The boat 1 has a hull 2, and an outboard motor 3 is detachably attached to the stern of the hull 2. The outboard motor 3 includes a bracket 4 attached to the stern.
And an outboard motor body 6 pivotally supported by a pivot shaft 5 with respect to the bracket 4.

The outboard motor main body 6 is provided with a power transmission device 8, and the power transmission device 8 is composed of a transmission case 9 constituting an outer shell thereof, and a transmission mechanism housed in the transmission case 9. The transmission case 9 is pivotally supported on the bracket 4 by the pivot shaft 5. The outboard motor body 6 is a two-cycle multi-cylinder engine 1 which is an internal combustion engine.
This engine 10 is detachably attached to the upper end of the transmission case 9 and is covered with a cover 11 so as to be openable and closable. The transmission case 9 extends downward into the water and has a cylindrical shaft 13 at the lower end of the transmission case 9.
And a propeller 14 is attached to the shaft 13.

Then, the propeller 14 is provided to the output portion of the engine 10 via the transmission mechanism of the power transmission device 8.
Are linked to work together.

2 to 8, the engine 10 described above is used.
Is the first cylinder 16, the second cylinder 17, and the third cylinder 18
Of a plurality of (three) cylinders, and these cylinders are arranged side by side so as to be vertically stacked.

The engine 10 includes the cylinders 16-1.
8 has a common crankcase 19, and this crankcase 19 has a vertically oriented crankshaft 20 whose axis is substantially vertical.
The crankshaft 20 is rotatably supported by the crankcase 19 about its axis.

The cylinder main bodies 22 of the cylinders 16 to 18 are integrally attached to the rear portion of the crankcase 19, and the axes of the cylinder main bodies 22 extend forward and backward in parallel with each other. A cylinder head 23 is detachably attached to the protruding end of each of the cylinder bodies 22. The cylinder bodies 22 are integrated with each other to form a cylinder block 24, and the cylinder heads 23 are also integrated with each other.

Each of the cylinder bodies 22 has a cylinder hole 25 whose axial center extends in the front-rear direction, and a piston 26 is slidably fitted in the cylinder hole 25 in the front-rear direction. Each of these pistons 26 is connected to the crankshaft 20 by a connecting rod 27.

In the cylinder hole 25, the cylinder head 2
The space surrounded by 3 and the piston 26 corresponds to the "inside of the cylinder", and the above "inside of the cylinder" where the piston 26 is close to the cylinder head 23 to some extent becomes the combustion chamber 29. Three spark plugs 30 are attached to the cylinder head 23 so as to correspond to the combustion chambers 29, and the discharge portions 31 of the spark plugs 30 face the combustion chambers 29.

Three intake ports 33 are formed on the front surface of the crankcase 19, and reed valves 34 are attached to the intake ports 33, respectively. In addition, the intake manifold 35,
A throttle body 36 that houses the throttle valve 36a,
And the silencer 37 is successively arranged. An inlet pipe 38 that opens rearward is attached to the upper end of the silencer 37. The inlet pipe 38, silencer 37, throttle body 36, intake manifold 3
5 and the reed valve 34 are communicated with each other by an intake passage 39 provided inside each of them.
Moreover, each of the intake passages 39 communicates with the intake port 33.

The throttle valves 36a are connected to the interlocking means 40.
Are connected to each other. When the operator operates the operation section, the throttle valves 36a are synchronized with each other via the interlocking means 40 to perform the same opening / closing operation.

In the cylinder body 22 around each cylinder hole 25, a plurality (three) of scavenging passages 41 are formed for each cylinder hole 25. Each of these scavenging passages 41 is arranged in the combustion chamber 2 inside the crankcase 19.
It communicates with 9.

An exhaust manifold 42 is attached to the left side of the cylinder block 24, and one end side of the first exhaust passage 43 in the exhaust manifold 42 is branched into a plurality (three) and formed in each cylinder body 22. Exhaust port 4
It opens to each combustion chamber 29 through 4. On the other hand, an exhaust guide 46 is provided between the cylinder block 24 and the transmission case 9, and the second exhaust passage 47 in the exhaust guide 46 and the other end side of the first exhaust passage 43 communicate with each other. Has been made. A third exhaust passage 48 is formed in the transmission case 9, one end of the third exhaust passage 48 communicates with the second exhaust passage 47, and the other end opens into the water through the shaft 13.

4 and 7, the engine 10 is provided with a water-cooling type cooling device 50. The cooling device 50 includes a first cooling water jacket 51 formed in the cylinder block 24 around each cylinder hole 25, a second cooling water jacket 52 formed in the exhaust manifold 42, and the second exhaust passage 47. A third cooling water jacket 53 formed in the exhaust guide 46 so as to surround the cooling water, and a fourth cooling water jacket 54 formed in the transmission case 9 so as to surround the third exhaust passage 48. The jackets 51 to 54 communicate with each other directly or via the cooling water communication passage 55. The lower end of the fourth cooling water jacket 54 communicates with the downstream side of the third exhaust passage 48.

A water pump for supplying cooling water 56 such as seawater is provided to the first cooling water jacket 51, and the cooling water 56 sequentially passes through the cooling water jackets 51 to 54 through the cooling water communication passage 55. And, it is drained into the water through the downstream end of the third exhaust passage 48. Then, in the middle of this flow, the cooling water 56 cools the first to third cylinders 16 to 18, whereby the first to third cylinders 1
6-18 cylinder heads 23 and cylinder blocks 24
Are kept in a predetermined temperature range.

In FIG. 2, fuel 5 is supplied to the engine 10.
A fuel supply device 60 for supplying 9 is provided. The fuel supply device 60 has a plurality (three) of fuel injection valves 61 corresponding to the first to third cylinders 16 to 18, and each of these fuel injection valves 61 is detachably attached to the throttle body 36. . These fuel injection valves 61 appropriately inject fuel 59 into the intake passage 39 extending from the throttle body 36 to the reed valve 34.

A low-pressure fuel pump 64 for sucking and supplying the fuel 59 stored in the fuel tank 63 to each of the fuel injection valves 61, and a high-pressure fuel pump for pressurizing and supplying the fuel 59 from the low-pressure fuel pump 64. 65 are provided in series. A water separation filter 66 and a vapor separator 67 are connected in series between the low pressure fuel pump 64 and the high pressure fuel pump 65. Further, as described above, the pressure regulator 69 that adjusts the pressure of the fuel 59 supplied to the fuel injection valve 61 to a predetermined pressure is provided, and the above devices are connected to each other by the fuel passage 70.

Each of the fuel injection valves 61 is of an electromagnetic type, and when it is electrically turned on (or off), the period is set as a fuel injection period, and the fuel 59 is taken into the intake passage 3 only during this period.
It is designed to be injected within 9.

In the above case, only the fuel tank 63 of the fuel supply device 60 is supported by the hull 2, and the others constitute the outboard motor 3.

In FIG. 2, an engine control device 73 for controlling the engine 10 is provided. The engine control device 73 includes an electronic control device body 74,
The ignition plugs 30, the fuel injection valve 61, the low pressure fuel pump 64, and the high pressure fuel pump 65 are electrically connected to the control device main body 74. A flywheel magnet 75 is attached to the upper end of the crankshaft 20. The flywheel magneto 75 supplies power to the control device main body 74 directly or via a battery.

Various sensors for detecting the driving state of the engine 10 are provided, and all of these are electrically connected to the control device main body 74.

That is, as the sensors, a crank angle sensor 76 for detecting the rotation angle of the crankshaft 20, a crankcase internal pressure sensor 77 for detecting the pressure in the crankcase 19, and a pressure in each of the cylinders 16 to 18 are detected. An in-cylinder pressure sensor 78, a knock sensor 79 for detecting a state inside the cylinders 16 to 18, an intake temperature sensor 80 for detecting a temperature in the intake passage 39, and a throttle opening sensor 81 for detecting an opening of the throttle body 36 are provided. Has been.

A cylinder temperature sensor 82 for detecting the temperature of each cylinder 16-18, a back pressure sensor 83 for detecting the upstream pressure in the third exhaust passage 48, an atmospheric pressure sensor 84 for detecting atmospheric pressure, and a cooling. A cooling water temperature sensor 85 for detecting the temperature of the water 56, a shift sensor 86 for detecting the shift state of the power transmission device 8, and a trim angle sensor 87 for detecting the vertical rotation position of the outboard motor 3 around the pivot shaft 5 are provided. It is provided.

On the other hand, an air-fuel ratio control device 89 is provided, and this air-fuel ratio control device 89 is provided with an exhaust gas introducing means 90 and an exhaust gas sensor 91 provided in this exhaust gas introducing means 90.

In addition, 93 is a starter, and 94 is an oil tank.

2 to 8, when the engine 10 is driven, in each of the first to third cylinders 16 to 18, when the piston 26 moves from the bottom dead center position on the crankshaft 20 side to the combustion chamber 29 side, The scavenging passage 41 and the exhaust port 44 are sequentially closed by the piston 26. Further, when the piston 26 moves to the combustion chamber 29 side in this way, the inside of the crankcase 19 becomes negative pressure. Then, the silencer 37, the throttle body 36, the intake manifold 35, the reed valve 34, and the intake passage 39 in the intake port 33 sequentially become negative pressure, and the outside air 97 which is air 97
Is sucked into the intake passage 39 from the intake port 33.

Next, the fuel injection valve 61 is connected to the intake air 98.
The fuel 59 is injected by and the air-fuel mixture 99 is generated. Then, this air-fuel mixture 99 becomes the crankcase 19 described above.
Inhaled into. This is the "inhalation process".

On the other hand, after the scavenging passage 41 and the exhaust port 44 are closed as described above, when the piston 26 is further moved to the combustion chamber 29 side, the air-fuel mixture which has already been sucked into the combustion chamber 29 is moved. 99 are compressed. This is the "compression process".

Immediately before the piston 26 reaches the top dead center, the air-fuel mixture 99 is ignited and burned by the discharge of the discharge portion 31 of the spark plug 30 controlled by the engine control device 73, and the gas expands. As a result, the piston 26 is pushed back to the crankshaft 20 side after passing the top dead center. This is the "explosion process".

By the movement of the piston 26 toward the crankshaft 20, the air-fuel mixture 99 sucked into the crankcase 19 is precompressed. The reed valve 34 is closed by the pressure at this time.

During the movement of the piston 26 toward the crankshaft 20, the exhaust port 44 is opened first. Then, the exhaust 100, which is the burned gas of the air-fuel mixture 99, is discharged through the exhaust port 44 and the exhaust port 44. This is the "exhaust process".

Then, the exhaust 100 has the first exhaust passage 4
3, the second exhaust passage 47, the third exhaust passage 48, and the shaft 13 are sequentially passed through to be discharged into the water. in this case,
The cooling water 56 after cooling the cylinders 16 to 18 passes through the fourth cooling water jacket 54 and the cooling water communication passage 55 and is discharged into the water together with the exhaust 100.

When the piston 26 moves toward the crankshaft 20 and the exhaust port 44 is opened as described above, the scavenging passage 41 is subsequently opened. Then, as described above, the air-fuel mixture 99 that has been pre-compressed in the crankcase 19 is discharged.
Is introduced into the combustion chamber 29 through the scavenging passage 41, and the air-fuel mixture 99 pushes out a portion of the burned gas remaining in the combustion chamber 29 into the first exhaust passage 43, and 99 fills the combustion chamber 29. This is the "scavenging process". And after this, the piston 26
Returns to the bottom dead center position.

In the above case, some of the air-fuel mixture 99 that has flowed into the combustion chamber 29 through the scavenging passage 41 is blown to the first exhaust passage 43 side (this is referred to as "fresh air blow-through phenomenon"). It is mixed with burnt gas and is discharged as the exhaust 100.

From the above-mentioned state, the piston 26 moves again to the combustion chamber 29 side, and the above-described processes are repeated to rotate the crankshaft 20. Then, the engine 10 outputs power through the crankshaft 20, and this power causes the propeller 14 to rotate via the power transmission device 8 to allow the ship 1 as a driven body to travel.

FIG. 10 is a diagram showing the movement of the piston 26. In this figure, the first cylinder 16, the second cylinder 17,
And the third cylinder 18 has a crank angle of 12 in this order.
Drive with a phase difference of 0 °.

1 to 9, the exhaust sensor 9
Reference numeral 1 is for detecting the properties of the exhaust 100. The detection signal of the exhaust sensor 91 is input to the control device main body 74, and the control of the control device main body 74 controls the length of the fuel injection period of the fuel injection valve 61 to be short or long.
The air-fuel ratio (A / F) of the air-fuel mixture 99 is automatically adjusted to an appropriate value.

In this case, the crank angle sensor 7
The driving state of the engine 10 is input to the control device main body 74 by various sensors such as No. 6, and the fuel injection period of the fuel injection valve 61 is controlled by the control device main body 74 so that the air-fuel ratio becomes a desired value. It is supposed to be done. In this way, the engine performance is improved and the fuel
The useless consumption of 9 is suppressed.

In FIG. 9, the exhaust sensor 91 is O ₂
A sensor, which is configured as follows.

That is, the exhaust sensor 91 has a circular protective outer cylinder 104 made of sheet metal, and a fastener 105 is attached to one end of the protective outer cylinder 104. Further, the same as above, a sensor element portion 106 made of zirconia is housed in the protective outer cylinder 104, and one end of this sensor element portion 106 has the protective outer cylinder 1
It projects from one end of 04. The sensor element unit 106
A lead wire 107 is provided for electrically connecting the control device body 74 to the control device body 74.

A hollow portion 108 is formed inside the sensor element portion 106. Same as above, platinum electrodes are plated on both the inside and outside surfaces of the sensor element portion 106, and the oxygen concentration, which is the property of the exhaust 100, is detected by the electromotive force generated according to the difference in oxygen concentration inside and outside the sensor element portion 106. .

Further, a protector 109 is provided which closes the projecting end of the sensor element portion 106 so as to be openable and closable.
The protector 109 includes a cylindrical sheet metal protector body 110 and a plurality of through holes 111 formed in the protector body 110.
0 is detachably attached to one end of the protective outer cylinder 104. Further, the exhaust gas 10 is passed through the through hole 111.
0 can freely flow inside and outside the protector body 110.

Further, a ceramic heater 112 is provided in the sensor element portion 106, and the heater 112 is provided.
By appropriate heating of the sensor element unit 106 by
The accuracy of the exhaust sensor 91 is improved.

Further, all the parts such as the protective outer cylinder 104 and the like which constitute the exhaust sensor 91 are located on the same axis 113 and have a slender shape as a whole.

1 to 9, the exhaust gas introducing means 90 of the air-fuel ratio control device 89 has a guide passage 115 for guiding the exhaust gas 100 to the outside of each cylinder hole 25 outside the system. Is a circular metal guide pipe 11
It is composed of 6.

The one end opening 117 of the guide passage 115 is
The second cylinder 17, which is an example of a certain cylinder, has an opening “inside the cylinder”, and the one end opening 117 is opened and closed by the operation of the piston 26 of the second cylinder 17. Also,
Same as above, the other end opening 118 of the guide passage 115 opens "in the cylinder" of the first cylinder 16 which is an example of another cylinder, and the other end opening 118 is opened and closed by the operation of the piston 26 of the first cylinder 16. It is supposed to do.

In the above case, the one end opening 117 is the other end opening 1
It is located slightly closer to the top dead center (combustion chamber 29) side than 18. The one-end opening 117 is located slightly above the top dead center side end of the exhaust port 44 (or at substantially the same position as the top dead center side end of the exhaust port 44), and
It is located closer to the top dead center than the scavenging port 41a.

A pressure accumulating chamber 119 having a cross section larger than that of the guide passage 115 is provided in the middle of the guide passage 115. The pressure accumulating chamber 119 is formed by a rectangular parallelepiped sheet metal accumulating case 120. .

In FIG. 1, the pressure accumulating chamber 119 will be described in more detail. The midway part of the guide passage 115 is divided, and one dividing end 122 on the one end opening 117 side of the guide passage 115 is the above-mentioned. It is connected to the lower wall of the pressure accumulating case 120 and opens into the pressure accumulating chamber 119. Also,
The other split end 123 of the guide passage 115 on the other end opening 118 side is connected to the upper wall of the pressure accumulating case 120 and opens into the pressure accumulating chamber 119. The pressure accumulation case 12
The exhaust gas sensor 91 is detachably fastened to the rear side wall of the sensor element unit 106 by a fastener 105,
The protector 109 covering this is the pressure accumulating case 120.
It faces the inside of the accumulator 119.

In FIG. 10, in each phase of the cylinders 16 to 18, the exhaust port 44 opens at about 90 ° from the top dead center (a portion in FIG. 10), and the scavenging port 41a opens at about 120 ° ( (Part b in FIG. 10). Also,
At about 240 °, the scavenging port 41a of the same as above is closed (part c in FIG. 10), and at about 270 °, the exhaust port 4 of the same as above.
4 is closed (part d in FIG. 10) and returns to the top dead center. Less than,
This is repeated.

3 to 6 and FIG. 10, the other end opening 118 immediately after the scavenging port 41a is opened by the sliding of the piston 26 in the "exhaust process" and the "scavenging process" of the first cylinder 16. Is opened "in the cylinder" (A part in FIG. 10). Then, the high-pressure exhaust gas 100 accumulated in the pressure accumulating chamber 119 in advance passes through the other end opening 118 and the first cylinder 1
6 is released into the “in-cylinder”, and the pressure accumulated in the pressure accumulating chamber 119 decreases (A to B in FIG. 10). The opening of the other end opening 118 means full opening, and the opening of one end opening 117 described later also means full opening.

When the pressure inside the accumulator 119 drops to some extent, the piston 26 slides in the "explosion process" of the second cylinder 17 immediately before the exhaust port 44 opens (or almost at the same time), and the scavenging port 41a. Before opening, the one end opening 117 is opened to “inside the cylinder” of the second cylinder 17 (see B part in FIG. 10). At this time, the second cylinder 17
Is immediately after the "explosion process", and the pressure of the exhaust 100 in the "in-cylinder" of the second cylinder 17 is high.
00 vigorously flows from the one-end opening 117 through the guide passage 115 into the pressure accumulating chamber 119 and is sufficiently accumulated therein, and the pressure in the accumulating chamber 119 rapidly increases (B to C in FIG. 10).
Part).

As described above, the one end opening 117 of the guide passage 115 in the second cylinder 17 is located at the top dead center side of the scavenging port 41a. Therefore, the "explosion process" of the second cylinder 17 is performed. The sliding of the piston 26 at “” causes the one end opening 117 to open at a timing earlier than that of the scavenging port 41a. Therefore, the high-pressure exhaust gas 100 smoothly flows into the accumulator chamber 119 through the one-end opening 117, and at that pressure, the air-fuel mixture 9 that has flowed into the “in-cylinder” through the scavenging port 41a that opens thereafter.
9 is prevented from flowing into the pressure accumulating chamber 119. Further, at this time, as described above, a part of the exhaust gas 100 in the high-pressure accumulator chamber 119 flows back into the “inside cylinder” of the second cylinder 17, so that the mixture 99 flows into the accumulator chamber 119 more. Certainly blocked.

As described above, the sliding of the piston 26 in the "explosion process" of the second cylinder 17 causes one end opening 117 to occur.
When the exhaust gas 100 is stored in the pressure accumulating chamber 119 between the time when the scavenging port 41a is opened and the time when the scavenging port 41a is opened. The volume of the pressure accumulating chamber 119 is set so that the pressure of the exhaust gas 100 in the pressure accumulating chamber 119 is kept higher than the pressure, so that the mixture 99 flows more reliably into the pressure accumulating chamber 119. Be blocked by.

On the other hand, as described above, immediately after the one end opening 117 of the second cylinder 17 is opened "in the cylinder",
Immediately before opening the scavenging port 41a, the other end opening 118 is closed in the first cylinder 16 (C in FIGS. 3, 5, and 10).
Part).

In the portions B to C in FIG. 10, reference numeral E in FIG. 10 is the same as in FIG. 10 except that the other end opening 118 is “in the cylinder” of the first cylinder 16.
The pressure at the other end opening 118 when it is opened. Further, reference symbol F in FIG. 10 indicates the pressure of the one-end opening 117 when the one-end opening 117 is opened “in the cylinder” of the second cylinder 17.

Further, P _{0 in} FIG. 10 is the maximum pressure in the “in-cylinder” of the first cylinder 16 when the other end opening 118 is open in the “in-cylinder” of the first cylinder 16. Further, the maximum pressure in the “in-cylinder” of the second cylinder 17 when the one-end opening 117 is opened in the “in-cylinder” of the second cylinder 17 is almost the same as P ₀ .

Then, the exhaust gas 100 in the pressure accumulating chamber 119 is discharged.
The minimum pressure of is maintained at a high pressure above the maximum pressure P ₀ . Therefore, the “scavenging process” of the first cylinder 16
Then, even if the air-fuel mixture 99 in the “in-cylinder” of the first cylinder 16 tries to flow into the pressure accumulating chamber 119 through the other end opening 118, this is lower than the maximum pressure P _{0, and} therefore the air-fuel mixture is The inflow of 99 into the pressure accumulating chamber 119 is blocked.

Thereafter, the one end opening 117 is opened "in the cylinder" of the second cylinder 17 until the second cylinder 17 shifts from the "intake process" to the "compression process", and the exhaust port 44 is opened.
Is closed immediately (or almost at the same time) (part D in FIG. 10).

As described above, in the first cylinder 16, the other end opening 1
18 is closed and the open end 117 of the second cylinder 17 is open (portions C to D in FIG. 10), the pressure accumulating chamber 1 having a high pressure.
From within 19, as described above, "in the cylinder" of the second cylinder 17
A reverse flow of the exhaust gas 100 occurs (in the direction of the imaginary line arrow in FIGS. 1, 5, and 6), and the pressure in the pressure accumulating chamber 119 decreases.

After this, the one end opening 117 and the other end opening 118 are both kept closed (FIG. 10).
(Middle D to A parts), the pressure in the pressure accumulating chamber 119 leaks to each “in-cylinder” of the first cylinder 16 and the second cylinder 17, and gradually decreases.
After that, the process returns to the portion A in FIG. 10 and the above-described operation is repeated.

When the other end opening 118 of the first cylinder 16 is opened again at the portion A in FIG.
6, the pressure in the "in-cylinder" is low immediately after the scavenging port 41a is opened as described above.
Between the parts, the exhaust gas 100 in the accumulator 119 flows into the “in-cylinder” of the first cylinder 16 through the other end opening 118.

The one end opening 117 is the other end opening 11
Since the second cylinder 17 is located on the top dead center side, the opening of the one end opening 117 of the second cylinder 17 when viewed from the top dead center is the other end opening 118 of the first cylinder 16 when viewed from the top dead center. Faster than timing, that is,
The pressure at the one end opening 117 when the one end opening 117 is opened (B portion in FIG. 10) is larger than the pressure at the other end opening 118 when the other end opening 118 is opened (A portion in FIG. 10). Become.

Therefore, the one end opening 11 is formed in the second cylinder 17.
When 7 is opened (B portion in FIG. 10), the exhaust gas 100 of the second cylinder 17 more smoothly flows into the pressure accumulation chamber 119 through the opening 117 at the one end and is sufficiently accumulated in the pressure accumulation chamber 119.

As a result of the above, the exhaust 100 of the second cylinder 17 can be reliably introduced into the accumulator 119 for each cycle. In addition, the air-fuel mixture 99, which is fresh air containing a large amount of O ₂ component, enters the accumulator 119 from the second cylinder 17 and the first cylinder 16.
Are prevented from flowing in.

Then, in the portions C to D in FIG.
The properties of the exhaust gas 100 in the pressure accumulating chamber 119 are detected by the exhaust gas sensor 91. In this case, in the “explosion process” in the second cylinder 17, the exhaust gas 10 generated in the second cylinder 17 is detected.
Since 0 is mostly composed of burnt gas, and is filled with the exhaust gas 100 of the second cylinder 17 while blocking the inflow of the air-fuel mixture 99 into the pressure accumulating chamber 119 as described above, The accumulator 119 will be filled with the burned gas generated in the second cylinder 17. Therefore, since the air-fuel mixture 99 is not mixed, the property of the exhaust 100 in each cycle of the second cylinder 17 is accurately detected by the exhaust sensor 91, that is, the O ₂ concentration is detected with high accuracy.

The above-mentioned one end opening 117 is formed in the piston 26.
May be opened toward the top dead center side so that it always remains open regardless of the operation of
17 may be formed on the cylinder head 23.

In FIG. 1, in order to lubricate the engine 10, lubricating oil is supplied to the "inside cylinders" of the first to third cylinders 16 to 18 together with the air-fuel mixture 99.

On the other hand, the guide passage 11 to the pressure accumulating chamber 119 is provided.
The one divided end 122 which is the inflow port of No. 5 is provided with a throttle portion 131 substantially coaxially with the one divided end 122.

Therefore, the exhaust 100 discharged from the "inside the cylinder" and flowing through the guide passage 115, and the cylinders 16 to 1
Lubricating oil particles which are unburned oil discharged from the "inside the cylinder" after lubricating 8 will flow from the large cross-sectional area of the guide passage 115 toward the small cross-sectional area of the throttle 131. Then, the flow direction is suddenly changed (arrow G in FIG. 1).

At this time, since the exhaust gas 100 has a small inertial force, the flow can be suddenly changed and smoothly flows into the pressure accumulating chamber 119 through the throttle portion 131. However, since the fine particles of the lubricating oil have a large inertial force, the flow cannot be suddenly changed, and a part of them cannot be changed in the guide passage 115.
It collides with the inner surface of and is attached to this inner surface. Then, the flow of the lubricating oil is weakened and the passage of the throttle 131 is suppressed. Therefore, the amount of the lubricating oil flowing into the pressure accumulating chamber 119 is reduced, so that the lubricating oil is suppressed from adhering to the sensor element portion 106 of the exhaust sensor 91.

Further, one of the divided ends 122 of the guide passage 115 is oriented vertically, and the one of the divided ends 122 is arranged.
Has an upper end opened to the bottom surface 132 of the pressure accumulating chamber 119. Further, at the upper end of the one divided end 122, the inner surface of the guide passage 115 is formed as a truncated cone-shaped inclined surface 115 a that is directed upward in the radial direction of the guide passage 115 toward the narrowed portion 131. Therefore, as described above, the exhaust gas 100 passes through the one divided end 122 and the accumulator chamber 11
When flowing into the inside 9, fine particles of lubricating oil
When the lubricating oil collides with and is adhered to the 5a, the lubricating oil smoothly flows down along the inclined surface 115a, so that fine particles of the lubricating oil are surely prevented from flowing into the accumulator 119. .

The core of the throttle portion 131 has a hole core and the sensor element portion 106 of the exhaust sensor 91 and the protector 109.
It is deviated from, and opens toward the inside of the pressure accumulating chamber 119.

Therefore, the exhaust gas 1 passes through the throttle 131.
Even if the fine particles of the lubricating oil flow into the pressure accumulating chamber 119 together with 00, the fine particles of the lubricating oil will be
6 and the protector 109 are prevented from directly colliding and easily adhering.

Further, a drain hole is formed on the bottom surface 132 of the pressure accumulating chamber 119, and in the illustrated example, the drain hole is constituted by the throttle portion 131 for simplification of the structure. Then, mainly when the exhaust 100 flows backward to the second cylinder 17 side (the phantom line arrow in FIG. 1) as described above, the exhaust 100 promotes the exhaust 100 and the self-weight causes the exhaust 100 to be on the bottom surface 132 of the accumulator chamber 119. The lubricating oil collected in the
The pressure accumulating chamber 119 is immediately passed through the guide passage 115 including 31.
Emitted from. This lubricating oil is used in the second cylinder 1
It is returned to the No. 7 side and used for lubrication of this second cylinder 17.

Further, the vicinity of the throttle portion 131, which is at least a part of the bottom surface 132 of the pressure accumulating chamber 119, is a conical inclined surface 132a which is inclined downward toward the throttle portion 131. .

Therefore, the bottom surface 132 of the pressure accumulating chamber 119 is
The lubricating oil that tries to collect upward flows smoothly on the inclined surface 132a toward the throttle 131 due to its own weight, and
As described above, the pressure is discharged from the pressure accumulating chamber 119 through the guide passage 115 including the throttle portion 131.

Therefore, it is possible to prevent the lubricating oil from trying to accumulate in the pressure accumulating chamber 119, and therefore, it is possible to more reliably prevent the lubricating oil from adhering to the sensor element portion 106 of the exhaust sensor 91.

Then, as described above, the exhaust sensor 91
The high-precision detection signal detected by the above is input to the control device main body 74 of the engine control device 73. Therefore, based on this input signal, the actual air-fuel ratio of the air-fuel mixture 99 supplied "in the cylinder" at that time Is accurately calculated.

On the other hand, the control device main body 74 is supplied with the detection signals of the throttle opening sensor 81, the cylinder temperature sensor 82, etc., and the drive state of the engine 10 is judged based on these input signals. A target air-fuel ratio suitable for the state is determined.

Then, the actual air-fuel ratio and the target air-fuel ratio are compared with each other, whereby the injection conditions such as the fuel injection period (injection amount) by the fuel injection valve 61 are determined, and the subsequent mixture 99 of the air-fuel mixture 99 is determined. The air-fuel ratio is automatically adjusted to a desired value that matches the driving state of the engine 10.

Although the above is based on the illustrated example, the engine 10 may be a 4-cycle engine. The engine 10 may be driven by an industrial machine other than a vehicle. The accumulator 119 has a guide passage 115.
It is not necessary to intervene in the middle part, and it may be connected to the end of the guide passage 115. That is, for example, in FIG.
The upper guide passage 115 of the pressure accumulating chamber 119 may be eliminated and only the lower guide passage 115 may be provided. In this case, the exhaust gas 10 flowing into the pressure accumulating chamber 119 through the lower guide passage 115.
0 is a period from B to D in FIG. 10 and flows back into the second cylinder 17 when the pressure in the second cylinder 17 becomes lower than the pressure in the pressure accumulating chamber 119.

(Example 2)

11 to 16 show the second embodiment.

11 to 13, the guide passage 11
The one end opening 117 of No. 5 is the above-mentioned first example which is an example of a certain cylinder.
The opening is made “inside the cylinder” of the cylinder 16, and the one end opening 117 is provided.
Is opened and closed by the operation of the piston 26 of the first cylinder 16. Further, the other end opening 118 of the guide passage 115 opens to “inside the cylinder” of the third cylinder 18 which is an example of another cylinder, and the other end opening 118 operates the piston 26 of the third cylinder 18. It is designed to open and close.

14 and 15, the pressure accumulating chamber 119 is constructed as follows.

That is, the pressure accumulating chamber 119 formed in the pressure accumulating case 120 is composed of an upper chamber 134 and a lower chamber 135 which are vertically arranged close to each other. One dividing end 122 of the guide passage 115 is opened through a plurality of first throttle portions 136 with respect to an intermediate portion in the vertical direction of the lower chamber 135. Further, the other divided end 123 of the guide passage 115 is opened to the bottom surface 132 of the lower chamber 135 through a drain hole 139 having the shape of a throttle. Further, one split end 122 of the guide passage 115 is short-circuited to the other split end 123 through the bypass passage 140 formed in the pressure accumulating case 120. In this case, the exhaust gas 1 flowing through the bypass passage 140 toward the other divided end 123
A part of 00 passes through the drain hole 139 and the lower chamber 13
5, the fine particles of the lubricating oil contained in a part of the exhaust 100 are attached to the inclined surface 115a and separated from the exhaust 100, and the lubricating oil is separated from the other end 1
Runs down to side 23. The bypass passage 140 may be omitted.

On the other hand, a second throttle portion 141 communicating with the lower chamber 135 is formed on the bottom surface 132 of the upper chamber 134, and the first throttle portion 136 and the second throttle portion 141 constitute the throttle portion 131. are doing. In addition, the second throttle unit 1
41 also serves as a drain hole, and is the bottom surface 1 of the upper chamber 134.
The reference numeral 32 is an inclined surface 132a which is inclined downward as it goes toward the second throttle portion 141.

11 to 16, the third cylinder 18
In the “exhaust process” and the “scavenging process”, the other end opening 118 is opened in the combustion chamber 29 immediately after the scavenging port 41a is opened by the sliding of the piston 26 in the third cylinder 18 (FIG. 16). Middle part A). Then, the exhaust gas 100 accumulated in the pressure accumulating chamber 119 in advance passes through the other end opening 118 and is released into the third cylinder 18, and the pressure accumulated in the pressure accumulating chamber 119 is reduced (A in FIG. 16). ~ Part B).

While the pressure in the pressure accumulating chamber 119 is decreasing, the piston 26 in the first cylinder 16 slides,
The one-end opening 117 is opened in the combustion chamber 29 immediately before the exhaust port 44 opens (or almost at the same time) and before the scavenging port 41a opens (B portion in FIG. 16). At this time, the first cylinder 16 is immediately after the “explosion process”, and the pressure of the exhaust gas 100 in the first cylinder 16 is high.
Is vigorously flowed into the pressure accumulating chamber 119 from the opening 117 through the guide passage 115 and is sufficiently accumulated therein, and the pressure in the accumulating chamber 119 rapidly rises (B to C in FIG. 16).

On the other hand, the one end opening 117 is the other end opening 11
Since it is located on the top dead center side with respect to No. 8, the timing at which the other end opening 118 in the third cylinder 18 opens is the first cylinder 1
6, the timing at which the one end opening 117 opens is delayed, and the pressure at the one end opening 117 when the one end opening 117 opens is larger than the pressure at the other end opening 118 when the other end opening 118 opens. Become.

Therefore, when the one-end opening 117 is opened as described above, the exhaust 100 of the first cylinder 16 causes the one-end opening 11 to open.
7 and the one divided end 122 to flow into the pressure accumulating chamber 119, and is sufficiently accumulated in the pressure accumulating chamber 119.

Next, as described above, immediately after the one end opening 117 in the first cylinder 16 is opened "in the cylinder",
The other end opening 118 is closed in the third cylinder 18 (C portion in FIG. 16). After that, the one-end opening 117 is closed when the first cylinder 16 shifts from the “suction process” to the “compression process” (portion D in FIG. 16).

As described above, while the other end opening 118 is closed and the one end opening 117 is open (C to D in FIG. 16).
Part), a reverse flow of the exhaust gas 100 occurs from the inside of the pressure accumulation chamber 119 having a high pressure to the first cylinder 16 (in the direction of the imaginary line arrow in FIG. 14), and the pressure of the pressure accumulation chamber 119 decreases.

After that, both the one end opening 117 and the other end opening 118 are kept closed (FIG. 16).
(Parts D to A), the pressure in the pressure accumulating chamber 119 gradually decreases due to leakage into the first cylinder 16 and the third cylinder 18. After that, the process returns to the portion A in FIG. 16 and the above operation is repeated.

When the other end opening 118 is opened again at the portion A in FIG. 16, immediately after the scavenging port 41a is opened in the third cylinder 18, the pressure in the "in-cylinder" is low.
6 between A and C, the pressure accumulating chamber 11 passes through the other end opening 118.
The exhaust gas 100 in 9 flows into the “inside cylinder” of the third cylinder 18.

Then, in the portions C to D in FIG.
A property of the exhaust gas 100 in the upper chamber 134 of the pressure accumulating chamber 119 is detected by the exhaust gas sensor 91. In this case, in the “explosion process” in the first cylinder 16, most of the exhaust gas 100 that is about to be discharged from the first cylinder 16 is composed of burnt gas, so the accumulator 119 is set to burn the burned gas. Will be satisfied with. Therefore, since the air-fuel mixture 99 is not mixed, the property of the exhaust gas 100 is accurately detected by the exhaust gas sensor 91.

As described above, the exhaust gas 1 in the first cylinder 16
00 flows into the pressure accumulating chamber 119 through the guide passage 115 (B to C in FIG. 16), the guide passage 115
Exhaust gas 10 from one divided end 122 toward the pressure accumulating chamber 119
A part of 0 flows into the lower chamber 135 through the first throttle 136. Further, the other part of the exhaust gas 100 in the guide passage 115 and most of the lubricating oil particles in the exhaust gas 100 are sent to the bypass passage 140 by the inertial force thereof, and from there to the other divided end 123 side of the guide passage 115. I will be told.

In the above case, the exhaust gas 100 flowing into the lower chamber 135 through the first throttle portion 136 is the same as the first throttle portion 1 described above.
The exhaust 10 because it suddenly changes direction when passing through 36
The lubricating oil is separated from 0 by inertial force, that is, the lower chamber 13
The exhaust gas 100 having a reduced content of lubricating oil is allowed to flow into the valve 5.

Further, the exhaust gas 1 flowing into the lower chamber 135
00 is made to flow into the upper chamber 134 through the second throttle portion 141. At this time, since the volume of the lower chamber 135 is large, the flow velocity of the exhaust gas 100 in the lower chamber 135 sharply decreases. Therefore, most of the lubricating oil particles in the exhaust gas 100 are on the bottom surface 132 of the lower chamber 135 due to their gravity. It is turned to and separated. Then, the lubricating oil accumulated on the bottom surface 132 is discharged to the other divided end 123 side through the drain hole 139.

Further, the lubricating fine particles that have flowed into the upper chamber 134 together with the exhaust gas 100 are the bottom surface 13 of the upper chamber 134.
When the lubricating oil tries to collect on the upper surface 2,
The upper part is turned to the second throttle part 141, and the second throttle part 1
It is discharged to the lower chamber 135 side through 41, and further discharged to the other divided end 123 side through the drain hole 139.

On the other hand, when the backflow of the exhaust gas 100 occurs from the pressure accumulating chamber 119 to the first cylinder 16 as described above (FIG. 16).
Middle C to D parts, direction of imaginary line arrow in FIG. 14,), upper chamber 1
Lubricating oil that tries to collect on the bottom surface 132 of 34 passes through the second throttle portion 141 more smoothly and is discharged to the lower chamber 135 side.

In the above case, the exhaust gas 100 in the upper chamber 134 reaches the upper chamber 134 by passing from the side of the one divided end 122 to the first throttle portion 136 and the second throttle portion 141. Since the amount of the lubricating oil contained therein is sufficiently reduced in two stages, the lubricating oil is more reliably suppressed from adhering to the sensor element portion 106 of the exhaust sensor 91.

Particularly, in FIG. 14, one of the divided ends 12 is
2 is located above the other split end 123.

Therefore, the lubricating oil that has flown into the pressure accumulating chamber 119 through the one divided end 122 together with the exhaust gas 100, due to its inertia force and natural flow, has the other divided end 123.
And is smoothly discharged from the pressure accumulating chamber 119.

Therefore, it is suppressed that the lubricating oil stays in the pressure accumulating chamber 119, and accordingly, the adhesion of the lubricating oil to the sensor element portion 106 of the exhaust sensor 91 is further suppressed.

Since other structures and operations are the same as those of the first embodiment, the same reference numerals are given to the drawings and the description thereof will be omitted.

(Example 3)

FIG. 17 shows the third embodiment.

According to this, one divided end 122 of the guide passage 115 is opened in the lower chamber 135 without passing the throttle portion.

Since the other structure and operation are the same as those of the second embodiment, the same reference numerals are given to the drawings and the description thereof will be omitted.

(Example 4)

FIG. 18 shows the fourth embodiment.

According to this, the lower chamber 135 shown in the second embodiment does not exist, and the one dividing end 122 and the pressure accumulating chamber 119 communicate with each other through the throttle portion 131, and the same dividing one is provided. The end 122 and the other divided end 123 have the drain hole 13
It communicates through 9.

Since other structures and operations are the same as those in the second embodiment, common reference numerals are given to the drawings and the description thereof will be omitted.

(Example 5)

FIG. 19 shows the fifth embodiment.

According to this, the end portion of the guide pipe 116 forming the one divided end 122 projects into the lower chamber 135. On the other hand, one end of a pipe 143 having the same cross-sectional shape as the guide pipe 116 is attached to the open end of the bypass passage 140 into the lower chamber 135, and the other end of the pipe 143 projects into the upper and lower chambers 135. There is.

The ends of the guide pipe 116 at the one end 122 and the other end of the pipe 143 are substantially parallel to each other and are vertically offset from each other.

Therefore, the exhaust gas 100 flowing from one divided end 122 side of the guide passage 115 to the pipe 143 side flows while bending in a zigzag shape.
Fine particles of the lubricating oil are effectively separated from zero due to the difference in the inertial force. Then, the separated lubricating oil is supplied to the lower chamber 135.
It is stored on the inner bottom surface 132, passes through the drain hole 139, and is discharged to the other divided end 123 side.

Since the other structure and operation are the same as those of the second embodiment, the same reference numerals are given to the drawings and the description thereof will be omitted.

(Example 6)

FIG. 20 shows the sixth embodiment.

Since this embodiment has almost the same structure, operation, and effect as those of the second to fifth embodiments, common reference numerals are given to the drawings, and duplicated description will be omitted.

In the figure, an oil sump chamber 144 is integrally formed in the lower part of the pressure accumulating case 120, and the downstream end of the bypass passage 140 opens into the oil sump chamber 144. An oil discharge port 145 is formed at the lower end of the oil sump chamber 144, and a plug 146 that closes the oil discharge port 145 so as to be openable and closable is provided.

Then, the lubricating oil separated from the exhaust gas 100 is stored in the oil storage chamber 144. Further, if the oil discharge port 145 is opened by operating the plug 146 as appropriate, the lubricating oil in the oil sump chamber 144 is discharged.

According to the above construction, the single guide passage 115 for connecting the cylinder and the pressure accumulating chamber 119 is provided, so that the structure is simplified. Further, the lubricating oil that has reached the accumulator 119 side from the cylinder side is prevented from flowing into the accumulator chamber 119 and returning to the cylinder side. Therefore, the lubricating oil is prevented from adhering to the exhaust gas sensor 91, and the lubricating oil is also prevented from being generated in the combustion chamber "in the cylinder" to generate exhaust smoke.

[0166]

According to the present invention, when the air-fuel ratio of the air-fuel mixture sucked into the cylinder is adjusted by the detection signal of the exhaust gas sensor for detecting the property of the exhaust gas, the exhaust gas is discharged outside the system. A guide passage for guiding is provided, a pressure accumulating chamber communicating with the guide passage is provided, and the property of the exhaust gas of the pressure accumulating chamber is detected by the exhaust sensor.

Therefore, when the exhaust gas having a large pressure flows into the pressure accumulating chamber through the guide passage, the large pressure of the exhaust gas is temporarily accumulated in the pressure accumulating chamber. For this reason,
Immediately after this, even if an exhaust gas having a low pressure tries to flow into the pressure accumulating chamber, the inflow is blocked. Then, the property of the exhaust gas having the large pressure is detected by the exhaust gas sensor.

By the way, particularly in a two-cycle engine, the pressure in the cylinder becomes maximum during the "explosion process", and the above pressure gradually decreases as the "scavenging process" progresses.

In the "explosion process", most of the exhaust gas to be discharged from the cylinder is composed of burnt gas, and at the maximum pressure, the cylinder is almost filled with burnt gas. There is.

On the other hand, in the "scavenging process", the exhaust gas is discharged from the inside of the cylinder into the exhaust passage. Immediately after this discharge, the inside of the exhaust passage reaches the maximum pressure, and the pressure is increased as the scavenging progresses. Taper off.

Immediately after the exhaust gas is discharged into the exhaust passage, the scavenging has just started, and the amount of fresh air blown into the exhaust passage side is small. Is composed of burnt gas, that is, the inside of the exhaust passage is almost filled with burnt gas at the maximum pressure.

Therefore, most of the exhaust gas that produces the maximum pressure in the exhaust system such as in the cylinder or in the exhaust passage is composed of burnt gas, and the exhaust gas having a large pressure passes through the guide passage and is accumulated in the accumulator chamber. Most of the above exhaust gas is burnt gas when flowing into the.

Then, as described above, once the large pressure exhaust gas is accumulated in the pressure accumulating chamber, immediately after that, the O ₂
Even if a fresh air mixture containing a large amount of components tries to flow into the pressure accumulating chamber, the pressure is low, so that the inflow is blocked. Therefore, as described above, the properties of the exhaust gas, which is almost burnt gas, are detected by the exhaust gas sensor.

Therefore, based on the detection by the exhaust sensor, the air-fuel ratio of the air-fuel mixture at that time can be accurately grasped, and according to this, the subsequent air-fuel ratio can be adjusted to the desired value more accurately. . As a result, improvement of engine performance and suppression of wasteful fuel consumption can be achieved more effectively.

A throttle portion is provided at the inlet of the guide passage to the pressure accumulating chamber.

Therefore, the exhaust gas discharged from the "inside of the cylinder" and flowing through the guide passage and the fine particles of the lubricating oil which is the unburned oil discharged from the "inside of the cylinder" after lubricating the cylinder are When an attempt is made to flow from a portion having a large cross-sectional area of the guide passage toward a portion having a small cross-sectional area in the narrowed portion, the direction of the flow is suddenly changed.

At this time, since the exhaust gas has a small inertial force, the flow can be suddenly changed and smoothly flows into the pressure accumulating chamber through the throttle portion. However, since the fine particles of the lubricating oil have a large inertial force, the flow cannot be changed suddenly, and some of them collide with the inner surface of the guide passage and are attached to this inner surface. Then, the flow of the lubricating oil is weakened and the passage of the throttle oil is suppressed.

Therefore, the amount of the lubricating oil flowing into the pressure accumulating chamber is reduced, so that the lubricating oil is suppressed from adhering to the sensor element portion of the exhaust sensor. As a result, the detection accuracy of the exhaust sensor and the responsiveness of the detection are improved, and the deterioration of the exhaust sensor is suppressed, so that the life is improved.

Further, as described above, since the adhesion of the lubricating oil to the sensor element portion of the exhaust sensor is prevented, it is not necessary to increase the capacity of the pressure accumulating chamber for this prevention. The volume of the chamber can be reduced to make the exhaust introduction means compact.

In the above case, a drain hole may be formed on the bottom surface of the pressure accumulating chamber.

With this arrangement, when the lubricating oil accumulates on the bottom surface of the pressure accumulating chamber, the lubricating oil passes through the drain hole,
It is discharged from the accumulator.

Therefore, the accumulation of the lubricating oil in the pressure accumulating chamber is suppressed, and the adhesion of the lubricating oil to the sensor element portion of the exhaust sensor is suppressed. Therefore, the above effect is further improved.

Further, at least a part of the bottom surface of the pressure accumulating chamber may be inclined downward so as to face the drain hole.

In this way, the lubricating oil that tries to collect on the bottom surface of the pressure accumulating chamber smoothly flows toward the drain hole on the inclined surface due to its own weight, and passes through the drain hole as described above. It is discharged from the accumulator.

Therefore, since the lubricating oil is prevented from accumulating in the pressure accumulating chamber, the lubricating oil is more reliably prevented from adhering to the sensor element portion of the exhaust sensor, and the above-mentioned effect is further improved. To do.

[Brief description of drawings]

FIG. 1 is a partially enlarged cross-sectional view of FIG. 3 in Embodiment 1.

FIG. 2 is a general diagram of the first embodiment.

FIG. 3 is a side view of the engine according to the first embodiment.

FIG. 4 is a rear partial cross-sectional view of the engine according to the first embodiment.

5 is a sectional view taken along line 5-5 of FIG. 3 in Example 1. FIG.

6 is a sectional view taken along line 6-6 of FIG. 3 in the first embodiment.

FIG. 7 is a bottom partial cross-sectional view of the lower portion of the outboard motor in the first embodiment.

FIG. 8 is a plan view of the engine according to the first embodiment.

FIG. 9 is a vertical cross-sectional view of the exhaust sensor according to the first embodiment.

FIG. 10 is an operation explanatory diagram based on the engine cycle according to the first embodiment.

FIG. 11 is a diagram corresponding to FIG. 3 in the second embodiment.

FIG. 12 is a diagram corresponding to FIG. 4 in the second embodiment.

FIG. 13 is a diagram corresponding to FIG. 8 in the second embodiment.

FIG. 14 is a diagram corresponding to FIG. 1 in the second embodiment.

15 is a partially enlarged partial cross-sectional view of FIG. 11 in Embodiment 2. FIG.

FIG. 16 is a diagram corresponding to FIG. 10 in the second embodiment.

FIG. 17 is a diagram corresponding to FIG. 1 in the third embodiment.

FIG. 18 is a diagram corresponding to FIG. 1 in Example 4.

FIG. 19 is a diagram corresponding to FIG. 1 in Example 5.

FIG. 20 is a diagram corresponding to FIG. 1 in Example 6.

[Explanation of symbols]

 10 Engine 16 First Cylinder (Cylinder) 17 Second Cylinder (Cylinder) 18 Third Cylinder (Cylinder) 26 Piston 29 Combustion Chamber 39 Intake Passage 41a Scavenging Port 43 First Exhaust Passage (Exhaust Passage) 44 Exhaust Port 47 Second Exhaust Passage (Exhaust Passage) 48 Third Exhaust Passage (Exhaust Passage) 59 Fuel 89 Air-Fuel Ratio Control Device 90 Exhaust Inlet Means 91 Exhaust Sensor 97 Outside Air 98 Intake 99 Mixture 100 Exhaust 106 Sensor Element Part 115 Guide Passage 115a Inclined Surface 116 Guide Pipe 117 One-end opening 118 Other-end opening 119 Accumulation chamber 120 Accumulation case 122 One divided end (inlet) 131 Throttling part (drain hole) 132 Bottom surface 132a Sloping surface

Claims (3)

[Claims] 1. An engine provided with an exhaust sensor for detecting a property of exhaust gas generated by combustion in a cylinder, and adjusting an air-fuel ratio of an air-fuel mixture sucked into the cylinder by a detection signal of the exhaust sensor. In the air-fuel ratio control device, a guide passage for guiding the exhaust to the outside of the system is provided, a pressure accumulating chamber communicating with the guide passage is provided, and the property of the exhaust of the pressure accumulating chamber is detected by the exhaust sensor, An air-fuel ratio control device for an engine, wherein a throttle portion is provided at an inlet of the guide passage to the pressure accumulating chamber. 2. The air-fuel ratio control device for an engine according to claim 1, wherein a drain hole is formed on the bottom surface of the pressure accumulating chamber. 3. The air-fuel ratio control device for an engine according to claim 2, wherein at least a part of the bottom surface of the pressure accumulating chamber is inclined downward toward the drain hole.