JP2000320314A - Direct cylinder injection-type two-cycle engine - Google Patents

Abstract

PROBLEM TO BE SOLVED: To supply, as much as possible, optimum amount of lubricating oil. SOLUTION: In a direct cylinder injection-type two-cycle engine 9, fuel is injected directly into respective cylinders, air is introduced into a crank chamber 36 via a muffler 34, a throttle body 33 and a reed valve 40, and lubricating oil is fed from a lubricating oil discharge port 54 into the crank chamber. The amount of lubricating oil to be supplied from the lubricating oil discharge port in the low-speed rotation is not less than the amount, in which carbonization is not generated and also not more than the amount obtained by adding approximately manufacturing errors to the amount in which carbonization is not generated.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a direct in-cylinder injection two-cycle engine in which lubricating oil is supplied from a lubricating oil discharge port into a crank chamber.

[0002]

2. Description of the Related Art In a two-cycle engine, air is introduced into a crank chamber through a silencer, a throttle body, a reed valve, and the like, and the air in the crank chamber is supplied to a cylinder, that is, a cylinder. In a conventional two-stroke engine, fuel such as gasoline and lubricating oil are supplied in a mixed state upstream of the reed valve. The lubricating oil in which this fuel is mixed has a lower viscosity than the lubricating oil alone.

[0003]

In recent years, it has been considered that fuel is directly injected into a cylinder in order to gradually reduce the amount of unburned fuel, that is, hydrocarbon (HC). As described above, when the fuel is directly injected into the cylinder, the lubricating oil alone is supplied into the crank chamber, and the viscosity increases. Thus, the characteristics of the lubricating oil
Since it is significantly different from the conventional fuel mixture, the optimum value of the lubricating oil supply amount is different from the conventional one.

An object of the present invention is to provide a direct in-cylinder injection two-stroke engine capable of supplying an optimal amount of lubricating oil as much as possible.

[0005]

In the direct-injection two-stroke engine (9) of the present invention, fuel is directly injected into each cylinder, and a silencer (34), a throttle body (33) and a reed are provided. Air is introduced into the crank chamber (36) via the valve (40), and lubricating oil is supplied from the lubricating oil discharge port (54) into the crank chamber. Then, the amount of the lubricating oil supplied from the lubricating oil discharge port during the low-speed rotation is equal to or more than an amount that does not substantially cause carbonization.

Further, the amount of the lubricating oil supplied from the lubricating oil discharge port at the time of low-speed rotation is equal to or more than an amount that does not substantially cause carbonization, and is equal to or less than an amount obtained by adding an approximately manufacturing error to the amount that does not generate carbonization. There are cases.

Further, the amount of lubricating oil supplied per cylinder from the lubricating oil discharge port during low-speed rotation may be a value between 20 cc and 55 cc per hour.

In some cases, the amount of lubricating oil per cylinder supplied from the lubricating oil discharge port during low-speed rotation is a value between 20 cc and 40 cc per hour.

[0009]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Next, an embodiment of a direct in-cylinder injection two-stroke engine according to the present invention will be described with reference to FIGS. FIG. 1 is a side view of an outboard motor equipped with a direct in-cylinder injection two-stroke engine according to the present invention. FIG. 2 is a plan sectional view of a direct in-cylinder injection two-cycle engine. FIG. 3 is a left side view of a main part of the two-stroke engine with the cylinder head removed. FIG. 4 is a right side view of essential parts of the two-stroke engine with the cylinder head removed. FIG. 5 is a graph showing the relationship between the throttle opening and the discharge amount of lubricating oil. In this specification, the cylinder arrangement side is the rear side with respect to the crankshaft, and the starboard side is the right side (the left side in FIG. 2). Further, in FIG.
Are shown as communicating, but are vertically displaced, and a substantially horizontal partition wall is provided between them so as to be shut off. Then, in FIG. 3, link 1
In FIG. 1, only the rear end is shown.

In FIG. 1, the outboard motor is covered by a housing consisting of an upper cowling 1, a lower cowling 2, an upper casing 3 and a lower casing 4 in this order from the upper side. A mounting bracket 6 for mounting the outboard motor to a small boat is mounted and fixed to a transom 7 of the small boat. An outboard motor main body is rotatably attached to a rear portion of the mounting bracket 6 via a pivot shaft or the like.

Inside the cowlings 1 and 2 composed of the upper cowling 1 and the lower cowling 2, a two-stroke engine 9 of a direct in-cylinder V-type six-cylinder is arranged. The rotation of the crankshaft 10 of the engine 9 is transmitted to a propeller 12 rotatably provided at a rear end of the lower casing 4 via a drive shaft, a bevel gear, a propeller shaft, and the like.

In FIG. 2, the crankshaft 10 of the engine 9 has a substantially vertical axis, and a pair of left and right cylinders 11 are distributed behind the crankshaft 10 so as to form a V-shape in the left-right direction. It is arranged. The pair of left and right cylinders 11 is provided in three stages in the vertical direction, and the cylinders 11 are arranged in a total of six cylinders. Further, six pistons 13 are connected to the crankshaft 10 via connecting rods 14, respectively. The pistons 13 are slidably disposed inside the respective cylinders 11. The case 17 of the engine 9 includes a cylinder block 20 that forms the six cylinders 11 described above, a crankcase 21 that covers the cylinder block 20 on the crankshaft 10 side, and a combustion chamber 1 of the cylinder block 20.
A pair of left and right cylinder heads 22 covering and closing the 1a side
It consists of

The cylinder head 22 is provided with a solenoid openable / closable injector 23 and a spark plug 24. The fuel pump sucks fuel such as gasoline from the fuel tank, pressurizes the fuel, and supplies the fuel to the injector 23 via the fuel rail 25 or the like. Each cylinder 11 is provided with three scavenging ports 26 and one exhaust port 27, and the piston 13 is moved from the bottom dead center position (that is, the dead center closer to the crankshaft 10) to the top dead center position. When it moves, the scavenging port 26 and then the exhaust port 27 are closed in this order. Conversely, piston 1
When 3 moves from the top dead center position to the bottom dead center position, the air outlet 27 and then the scavenging port 26 are opened in this order.

At the front of the crankcase 21, an air inlet 31 is formed so as to bulge forward.
The throttle body 33 is connected to the front of the throttle body 33, and a silencer 34 is connected to the front of the throttle body 33. The throttle body 33 has a throttle valve 3
3a, and a valve shaft 33b of the throttle valve 33a.
Are connected to and linked to a throttle lever (not shown) via a throttle wire (not shown) or the like.
Then, operate the throttle lever to set the throttle valve 3
By changing the opening of the throttle body 3a, the throttle body 3
3 is adjusted.

Cylinder block 20 and crankcase 2
The crank chamber 36 covered by 1 is vertically partitioned by the partition wall into the number of cylinders, that is, six, and six small crank chambers 37 are formed. Similarly, the air introduction section 31 is also partitioned into upper and lower cylinders by the number of cylinders to form six air passages 32. The air passages 32 are mutually separated from the crank small chambers 37 corresponding to the same cylinder. The cylinder is in communication with the small crank chamber 37 corresponding to another cylinder. Each of the air flow paths 32 is provided with a reed valve 40 for preventing backflow. Also, each crank chamber 37 is
The scavenging port 26 of the corresponding cylinder 11 communicates with a scavenging passage 38. Each exhaust port 27 of the left cylinder 11 joins the left collective exhaust passage 41, while each exhaust port 27 of the right cylinder 11 joins the right collective exhaust passage 42. The combustion gas in the cylinder 11 is
Then, the air is discharged from the boss of the propeller 12 to the outside of the outboard motor through a left exhaust gas passage 41 and a right exhaust gas passage 42 through a muffler or the like.

An oil pump 52 such as a mechanical pump driven in conjunction with the rotation of the crankshaft 10 is connected to the lubricating oil tank 51 via a suction pipe 50. The pump 52 has a number of cylinders. Are formed. The air flow path 32 communicating with the cylinder 11 disposed on the right side is located above the left side wall 31a, while the air flow path 32 communicating with the cylinder 11 disposed on the left side is located on the right side. A discharge pipe 5 as a lubricating oil discharge port is provided on an upper portion of the wall 31b.
4 are provided so as to protrude from the outside to the inside by about 10 mm. The tip of the discharge pipe 54 extends right behind the reed valve 40. The outer end of the discharge pipe 54 is connected to the outlet 53 of the pump 52 by a supply hose 56 as a supply pipe. When the pump 52 operates, the lubricating oil in the lubricating oil tank 51 is discharged from the discharge pipe 54 into the air flow path 32 via the supply hose 56. It should be noted that in FIG.
Although the discharge pipe 54 is shown on both side walls of the left side wall 31a and the right side wall 31b of the (air passage 32) for easy understanding, in actuality, in each air passage 32, the left side wall 31a or the right side wall 31b Is provided in any one of.

The oil pump 52 is provided with a pump lever 96 for changing the discharge flow rate. One end of the pump lever 96 is connected to an output lever 33c of a valve shaft 33b of the throttle body 33 via a link 101 which is an interlocking mechanism, and the pump lever 96 rotates the valve shaft 33b of the throttle body 33. It is rotating in conjunction with. Then, when a throttle lever (not shown) is operated, the valve shaft 33b of the throttle body 33 rotates, and the opening of the throttle valve 33a (ie, the throttle opening).
Is changed, and the pump lever 96 is rotated via the output lever 33c of the throttle body 33, the link 101, and the like. Then, as the rotation of the pump lever 96 increases (that is, as the throttle opening increases), the oil discharge amount of the oil pump 52 increases as shown in FIG. That is, in FIG. 5, at low speed rotation such as idling with a small throttle opening, the discharge amount per one port (ie, discharge amount per cylinder), which is the amount of lubricating oil discharged from one discharge pipe 54, is about When the engine 9 is rotated at a high speed with a small throttle opening of 35 cc / Hr and the throttle opening is increased, the discharge amount per unit is increased.

In this embodiment, the discharge amount per cylinder at the time of low-speed rotation is about 35 cc / Hr. However, if the discharge amount is too small, carbonization occurs and carbon clogging occurs. Occurs. Also, at low temperature start,
Since the viscosity of the lubricating oil increases, if the discharge amount per cylinder during the low-speed rotation is too large, the cranking rotation speed will not rise to a predetermined value. Therefore, the optimal value of the discharge amount per cylinder at low speed rotation is
The maximum value is about 20 cc / Hr or more, which is an amount at which substantially no carbonization occurs, and the maximum value is about 55 cc / Hr or less, which is an amount at which a predetermined increase in the cranking speed is substantially impossible. In addition, if the discharge amount of the lubricating oil is increased, the consumption amount of the lubricating oil naturally increases. Therefore, when the discharge amount of the lubricating oil is as small as possible, the running cost and the like can be reduced. Therefore, it is preferable that the discharge amount per cylinder at the time of low-speed rotation be an amount that does not substantially cause carbonization, but a manufacturing error of ± 7 cc / Hr, that is, a manufacturing error of a total of 14 cc / Hr on the plus side and the minus side. Therefore, it is necessary to determine in consideration of these factors. Therefore, the discharge amount per cylinder at the time of low speed rotation is approximately 20 cc / Hr to 34
Although the value is between cc / Hr, considering the safety factor, the maximum value should be less than the value of about 40 cc / Hr which is the sum of the minimum value of about 20 cc / Hr and the manufacturing error. Is preferred.

Further, a drain inlet 61 is formed in the scavenging passage 38 on the lower side of each cylinder 11, as shown in FIGS. On the other hand, six drain return ports 6
3 is formed on the right side wall 31b of the air introduction part 31 in the odd-numbered air flow path 32 from the upper side, and is formed in the air introduction part 31 in the even-numbered air flow path 32 from the upper side.
On the left side wall 31a. Then, each drain return port 63 is connected to a drain inlet 61 corresponding to another cylinder 11 via a check valve (not shown).
4 are connected.

When the oil pump 52 is mounted, first, the oil pump 52 is connected to the suction pipe 50.
The lubricating oil tank 51 is connected to the discharge pipe 54 by a supply hose 56, and then the oil pump 52 is manually driven to fill the suction pipe 50 and the supply hose 56 with lubricating oil. The oil pump 52 is mounted so as to be linked with the crankshaft 10. Accordingly, the lubricating oil is discharged from the discharge pipe 54 from the beginning of the running-in operation of the engine 9 and the crank chamber 36 and the cylinder 11
Can be quickly lubricated.

When the engine 9 configured as described above is operated, the air in the cowlings 1 and 2 is sucked in from the silencer 34, and the flow rate of the air is adjusted by the throttle body 33. It flows into the air flow path 32 of the air introduction part 31. In this air flow path 32, the lubricating oil is discharged from the discharge pipe 54 and flows into the small crank chamber 37 of the crank chamber 36 along with the flow of air. The air in the crank chamber 36, that is, the air in the small crank chamber 37 flows into the combustion chamber 11 a of the cylinder 11 through the scavenging passage 38. This combustion chamber 11a
The fuel is discharged from the injector 23 as appropriate, and is ignited by the spark plug 24 and burned. The combustion gas, that is, the exhaust gas, passes through the left collective exhaust passage 41 and the right collective exhaust passage 42 and is exhausted to the outside of the outboard motor as described above.

As shown in FIG. 2, the crankshaft 10 rotates clockwise in a plan view, and the air in the crank chamber 36 is rotated in the same direction as the rotation of the crankshaft 10 due to the rotation of the crankshaft 10. That is, it is rotating clockwise. Then, the lubricating oil discharged from the discharge pipe 54 can scatter far along the flow of the air. The scattered lubricating oil can lubricate lubricating parts such as a small-end bearing and a large-end bearing, which are connecting portions of the connecting rod 14, and a sliding surface of the piston 11 in the cylinder 11,
The back surface of the piston 13 (that is, the crankshaft 10
Side surface) can be cooled.

The distal end of the discharge pipe 54 is located close to the reed valve 40 while being close to the reed valve 40, and the lubricating oil discharged from the discharge pipe 54 is supplied to the reed valve which operates in a flutter pattern. It is distributed by 40 opening and closing operations.

In the scavenging passage 38 below each cylinder,
Drain such as lubricating oil may accumulate. A drain inlet 61 is provided in the scavenging passage 38, and the drain inlet 61 is connected to a drain return port 63 of another cylinder via a return hose 64. Therefore, when the air pressure in the drain inlet 61 becomes higher than the air pressure in the air flow path 32 of the other cylinder, the drain accumulated near the drain inlet 61 passes through the return hose 64 and passes through the other cylinder. Into the drain return port 63. In this way, it is possible to reduce the drain flowing into the combustion chamber 11a of the cylinder 11 and burning. The backflow from the drain return port 63 to the drain inlet 61 is prevented by a check valve (not shown).

Further, in the air passage 32 communicating with the right cylinder 11, the left side wall 31 of the air passage 32
On the other hand, in the air flow path 32 communicating with the left cylinder 11, a discharge pipe 54 is provided on the right side wall 31 b of the air flow path 32, and lubricating oil from the discharge pipe 54 to the cylinder 11 Are substantially the same distance as shown by arrows A and B. Therefore, the amount of the lubricating oil supplied to each cylinder 11 is substantially the same, and is supplied in a well-balanced manner.

The discharge amount per cylinder at the time of low-speed rotation is approximately 20 cc / Hr
As described above, the cranking speed is not more than a predetermined rise of approximately 55 cc / Hr or less, so that the occurrence of carbonization can be prevented and the cranking speed can be smoothly started. The rotation speed can be increased to a value that can be performed. In addition, about 40 cc / Hr, which is about 20 cc / Hr or more, which is an amount that does not substantially generate carbonization, and about 20 cc / Hr, which is an amount that does not generate carbonization, and about 40 cc / Hr, which is obtained by adding a substantially manufacturing error
When it is not more than Hr, the consumption of lubricating oil can be reduced as much as possible. Further, since the lubricating oil is not diluted with the fuel, the formation of the oil film is good, and the seizure can be prevented, and the lubrication efficiency is improved. Therefore, the supply amount of the lubricating oil can be reduced as compared with the case where the conventional lubricating oil is mixed with the fuel. For example, 35 cc / Hr in this embodiment is reduced by about 25% as compared with the case where lubricating oil is mixed with fuel as in the conventional case.

The embodiment of the present invention has been described above in detail.
The present invention is not limited to the above embodiment,
Within the gist of the present invention described in the claims,
Various changes can be made. Modification examples of the present invention are exemplified below. (1) In the embodiment, the engine 9 is a V-type six-cylinder, but the number and type of the cylinders can be changed as appropriate.

(2) The positional relationship between the left and right members can be reversed. (3) In the embodiment, the lubricating oil discharge port is constituted by the discharge pipe 54, but is not necessarily formed in a pipe shape, and may be formed directly on the side walls 31 a and 31 b of the air introduction part 31. It is. However, the lubricating oil discharge port is formed in a pipe shape, and the side walls 31a, 31b
When the lubricating oil is projected into the inside of the air flow passage 32, the discharged lubricating oil can be prevented from flowing along the side walls 31a, 31b as much as possible. As a result, the lubricating oil can be scattered efficiently. Further, the discharge of the lubricating oil can be appropriately selected, such as mist or linear injection or dripping. Further, the lubricating oil can be discharged intermittently or continuously.

(4) In the embodiment, when the oil pump 52 is mounted, the oil pump 52 is driven by hand. However, the oil pump 52 can be driven by a drive source other than the crankshaft 10. (5) In the embodiment, the air introduction part 31 is cast integrally with the crankcase 21, but the air introduction part 3
1 can be formed separately from the crankcase 21 and then integrally formed by welding or bolting. (6) In the embodiment, the discharge pipe 54 as the lubricating oil discharge port is provided above the side walls 31a and 31b, but the arrangement position on the side walls 31a and 31b can be appropriately changed. For example, it is also possible to be below the side walls 31a, 31b. However, since the lubricating oil falls due to gravity, it is preferable that the lubricating oil be located above the side walls 31a and 31b.

[0030]

According to the present invention, since the fuel is directly injected into each cylinder, the unburned fuel, that is, the hydrocarbon (H
The discharge amount of C) can be reduced as much as possible. And
The lubricating oil is supplied to the crank chamber from the lubricating oil discharge port without being mixed with the fuel. The amount of the lubricating oil supplied from the lubricating oil discharge port is substantially equal to or more than the amount at which the lubricating oil is not generated at the time of low-speed rotation. As a result, carbon clogging can be prevented. In this way, an optimal amount of lubricating oil can be supplied during low-speed rotation of the direct in-cylinder injection two-cycle engine.

Further, the amount of the lubricating oil supplied from the lubricating oil discharge port at the time of low-speed rotation is equal to or more than an amount that does not substantially cause carbonization, and is equal to or less than an amount obtained by adding an approximately manufacturing error to the amount that does not generate carbonization. In this case, the direct in-cylinder injection two-stroke engine can be lubricated in an optimal state with a minimum amount of lubricating oil.

Further, when the amount of lubricating oil per cylinder supplied from the lubricating oil discharge port during low-speed rotation is a value between approximately 20 cc and 55 cc per hour, the occurrence of carbonization is prevented. And the engine can be started smoothly by increasing the cranking speed to a predetermined value.

When the amount of lubricating oil per cylinder supplied from the lubricating oil discharge port during low-speed rotation is a value between about 20 cc and 40 cc per hour, carbonization is prevented. And consumption of lubricating oil during low-speed rotation can be minimized.

[Brief description of the drawings]

FIG. 1 is a side view of an outboard motor equipped with a direct in-cylinder injection two-stroke engine according to the present invention.

FIG. 2 is a plan sectional view of a direct in-cylinder injection two-cycle engine.

FIG. 3 is a left side view of a main part of the two-stroke engine with a cylinder head removed.

FIG. 4 is a right side view of essential parts of the two-stroke engine with the cylinder head removed.

FIG. 5 is a graph showing a relationship between a throttle opening and a discharge amount of lubricating oil.

[Explanation of symbols]

 9 Engine 33 Throttle body 34 Silencer 36 Crank chamber 40 Reed valve 54 Discharge pipe (lubricating oil discharge port)

 ────────────────────────────────────────────────── ─── Continuing on the front page (72) Inventor Tokuyoshi Hiraoka 1400 Shimbashi-cho, Hamamatsu-shi, Shizuoka F-term in Sanshin Industrial Co., Ltd. (reference) 3G013 AA03 AA09 AA12 AB01 BA02 BA04 BB04 BB08 BB16 BB32 BC02 BC03 BC04 BD02 BD12 BD47 CA01 CA06 EA04

Claims (4)

[Claims] 1. A fuel is directly injected into each cylinder, air is introduced into a crank chamber through a silencer, a throttle body and a reed valve, and
In a direct in-cylinder injection two-cycle engine in which lubricating oil is supplied from the lubricating oil discharge port into the crank chamber, the amount of lubricating oil supplied from the lubricating oil discharge port during low-speed rotation is equal to or greater than an amount that does not substantially cause carbonization. A direct in-cylinder injection two-cycle engine characterized by the following. 2. A fuel is directly injected into each cylinder, air is introduced into a crank chamber through a silencer, a throttle body, and a reed valve, and
In a direct in-cylinder injection two-stroke engine in which lubricating oil is supplied from the lubricating oil discharge port into the crank chamber, the amount of lubricating oil supplied from the lubricating oil discharge port during low-speed rotation is at least an amount that does not substantially cause carbonization. A direct in-cylinder injection two-stroke engine characterized by being equal to or less than an amount obtained by adding a substantially manufacturing error to the amount in which carbonization does not occur. 3. A fuel is directly injected into each cylinder, air is introduced into a crank chamber through a silencer, a throttle body, and a reed valve, and
In a direct in-cylinder injection two-cycle engine in which lubricating oil is supplied from the lubricating oil discharge port into the crank chamber, the amount of lubricating oil supplied per cylinder from the lubricating oil discharge port during low-speed rotation is approximately one hour. A direct in-cylinder injection two-stroke engine characterized by a value between 20 cc and 55 cc per cylinder. 4. A fuel is directly injected into each cylinder, and air is introduced into a crank chamber through a silencer, a throttle body and a reed valve, and
In a direct in-cylinder injection two-cycle engine in which lubricating oil is supplied from the lubricating oil discharge port into the crank chamber, the amount of lubricating oil supplied per cylinder from the lubricating oil discharge port during low-speed rotation is approximately one hour. A direct in-cylinder injection two-stroke engine characterized by a value between 20 cc and 40 cc per cylinder.