JPH05340264A - V type four cylinder four stroke engine - Google Patents

Abstract

PURPOSE:To reduce generation of primary inertial couple force by specifying the relative angle and phase angle of each crank pin with respect to the V-type enlarging angle of a cylinder axial line, and also specifying the reciprocating part weight of each cylinder. CONSTITUTION:In a V-type four stroke engine 21, right and left cylinder axial lines (C), (C) are expanded in V-type, and also the ignition intervals of respective cylinders 26 are set at different intervals. In this case, when the V-type expansion angle is set to theta, the relative angle between first and second crank pins 24a, 24b is set to pi-2theta, and also the phase angles of first and third crank pins 24b, 24d are set to 360 deg., and the phase angles of second and fourth crank pins 24b, 24d are set to 360 deg.. On the other hand, in each reciprocating part mass of each cylinder 26 according to each crank pin 24, the reciprocating part masses of second and third cylinders are set to levels larger than the reciprocating part masses of first and fourth cylinders. It is thus possible to reduce primary inertial couple force.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a V-type 4-cylinder 4-stroke engine, in which the ignition intervals of the cylinders that expand into a V-type are unequal intervals, and in particular, they are suitable for mounting on an outboard motor. It is a thing.

[0002]

2. Description of the Related Art In an outboard motor using an internal combustion engine as a power source, mounting a 4-stroke engine is advantageous in terms of fuel consumption and emission control because it does not blow through fresh air unlike a 2-stroke engine. An outboard motor equipped with a V-type 6-cylinder 4-stroke engine having a vertical crankshaft is known from Japanese Patent Application Laid-Open No. 62-267561.

[0003]

By the way, it is conceivable to install a four-cylinder V-type four-stroke engine in which the number of cylinders is reduced in order to cope with an arbitrary output in addition to the reduction in weight. It is necessary to consider the commercial characteristics. In the V-type 4-cylinder 4-stroke engine, if the ignition intervals of the cylinders are equal, the influence of the reaction force of the drive torque can be suppressed, but the primary inertia couple is large. When the ignition intervals are unequal intervals, especially when the crank angle is 180 °, the influence of the primary inertia couple can be suppressed, but the reaction force of the driving torque becomes large, and it is mounted on the outboard motor. In the case of a thing, the transmission of vibration to the hull side becomes large.

Therefore, an object of the present invention is to expand into a V-shape.
To provide a V-type 4-cylinder 4-stroke engine capable of suppressing the generation of a primary inertia couple while suppressing the influence of the reaction force of the driving torque even if the ignition intervals of the two cylinders are unequal intervals. is there.

[0005]

In order to solve the above problems, the present invention is a V-type 4-cylinder 4-stroke engine in which the cylinder axis is expanded to a V-type and the ignition intervals of the cylinders are unequal intervals. In the crankpin of the crankshaft, when the V-shaped expansion angle of the cylinder axis is θ, the relative angle of the first and second crankpins from one end side is π−2θ,
The phase angle of the first and third crankpins is 360 °, the phase angle of the second and fourth crankpins is 360 °,
The mass of each reciprocating portion of the cylinder corresponding to each crankpin is such that the mass of each reciprocating portion of the second and third cylinders is larger than the mass of each reciprocating portion of the first and fourth cylinders. In the above, for example, each mass of the piston pins of the second and third cylinders is larger than each mass of the piston pins of the first and fourth cylinders. Specifically, the piston pins of the first and fourth cylinders are hollow, and the piston pins of the second and third cylinders are solid or more than the piston pins of the first and fourth cylinders. It is characterized by being thick and hollow.

[0006]

[Operation] V-type 4 in which the ignition intervals of the cylinders are unequal intervals
Even in a cylinder four-stroke engine, the relative angle between the first and second crank pins is π−2θ (θ: V-shaped expansion angle of the cylinder axis), and the phase angle between the first and third crank pins is Since the mass of each reciprocating part of the second and third cylinders is set to be larger than the mass of each reciprocating part of the first and fourth cylinders by setting the phase angle of 360 ° and the phase angle of the second and fourth crankpins to 360 °, The secondary inertial couple is canceled or the primary inertial couple is reduced according to the difference in the mass of the cylinder reciprocating portions. In addition, the adjustment is simple because it is performed by adjusting the mass of the piston pin individually. Moreover, since the piston pin is processed, it is easy to process.

[0007]

Embodiments of the present invention will be described below with reference to the drawings. 1 and 2 showing an application example of the V-type 4-cylinder 4-stroke engine to the outboard motor according to the present invention, 1
Is an outboard motor mounting means, and 20 is an outboard motor body. The outboard motor mounting means 1 includes a stern bracket 2 fixed to the stern of a hull (not shown), and a swivel case 4 swingably supported by the stern bracket 2 via a tilt shaft 3 having a horizontal axis. And a swivel shaft 5 rotatably supported by the swivel case 4 and having an axis line in a substantially vertical direction.
The support member 8 that is integrally provided above and below the swivel shaft 5 and supports the outboard motor body 20 includes an upper support member 8a and a lower support member 8b. Further, the upper support member is integrally provided with a mounting portion 7 for an operation handle or a remote control steering cable extending forward. Then, the upper support member and the lower support member 8
Are for supporting the outboard motor main body 20 via vibration-proofing means (vibration-proof rubber) not shown.

The outboard motor body 20 is provided with four upper and lower cylinders 26, 26 extending rearward and rearward in a left-right V-shape with the crankshaft 22 oriented substantially vertically, and the left and right cylinder axis lines C are provided. , C, V type 4 with V type expansion angle less than 90 °
The cylinder four-stroke engine 21 is arranged in the upper part, and the case means 60 is assembled below the four-stroke engine 21. Engine 2
1, reference numeral 23 is a journal portion of the crankshaft 22, 2
4 is the same crank pin, 25 is the same crank web, 27 is a piston, 28 is a piston pin, 29 is a connecting rod, 3
Reference numeral 1 is a crankcase, 32 is a cylinder block, 33 is a cylinder head, 34 is a cylinder head cover, 35 is a timing belt device, 36 is a cam shaft, 37 is a rocker arm, 38 is an intake valve, and 39 is an exhaust valve. V above
The 4-cylinder 4-stroke engine 21 is covered with an engine cover 41, and is formed inside the V bank from an air intake 42 provided in the engine cover 41 via a silencer 43, a carburetor 44, and an intake pipe 45. Intake is performed in each of the two left and right intake passages 46, 46, 47 is a combustion chamber, and 48 is an exhaust passage formed outside the V bank of the cylinder head 33. This exhaust passage 48
Extend downward outside the V bank of the cylinder block 32.

A mount case 51 is integrally provided below the engine 21 by bolting to the lower surfaces of the crankcase 31 and the cylinder block 32. Reference numeral 52 is a starter motor, 53 is a flywheel, 54 is a ring gear, and 56 is an oil filter. The case means 60 assembled below the V-type 4-cylinder 4-stroke engine 21 is the mount case 5.
1 Extension case 61 bolted to the bottom
And a gear case 71 bolted to the lower surface of the extension case 61.

The extension case 61 accommodates the vertical shaft 62 directly connected to the lower end of the crank shaft 22, and is connected to two lower exhaust passages 48, 48 formed in the vertical direction outside the V bank of the cylinder head 33. The exhaust pipes 63, 63 and the oil pan 64 bolted to the lower surface of the mount case 51 are housed. 64b is an oil drain bolt, and 65 is an upper mount lid portion integrally formed with the oil pan 64. The gear case 71 includes a driving bevel gear 7 at a lower portion of the vertical shaft 62 and a lower end portion thereof.
2. Propeller shaft 7 equipped with propeller 73 as a propelling means
4, a pair of driven bevel gears 7 for advancing and retreating the ends thereof
5,76 and dog clutch 7 for switching between forward and backward movements therebetween
7, the bell crank type clutch operating mechanism 78 and an operating shaft (not shown) are housed. Reference numeral 82 is a partition wall, 83 is an exhaust chamber, 84 is a propeller shaft holder, 86 is an exhaust port, 91 is a cooling water intake port, 92 is a water pump, and 94 is a hose.

In the outboard motor having the above construction, the V-type 4-cylinder 4-stroke engine 21 in which the V-type expansion angle of the left and right cylinder axes C, C is less than 90 ° is shown in FIGS.
As shown in FIG.
a and piston 27a, second crank pin 24b and piston 27b, third crank pin 24c and piston 27c, fourth crank pin 24d and piston 27
In the case of d, the crank pin phase angle and the cylinder ignition sequence will be described below. Here, the first piston 27a and the third piston 27c are on one cylinder 26, 26 row side in the V-shaped arrangement, and the second piston 27b and the fourth piston 27d are on the other cylinder 26, 26 row side. belongs to.

First, regarding the crankpin phase angle,
When the V-shaped expansion angle of the left and right cylinder axes C, C is θ, the first crank pin 24a and the second crank pin 2
The relative angle of 4b is π−2θ, and as shown in FIGS. 3 and 4, the phase angle between the first crank pin 24a and the third crank pin 24c is 360 °, and the second crank pin 24 is
The phase angle between b and the fourth crank pin 24d is set to 360 °. Regarding the cylinder ignition sequence, when the rotation direction of the crankshaft is the arrow R direction, the cylinder 26 corresponding to the first piston 27a, the second piston 27b, the third piston 27c, and the fourth piston 27d ... The ignition order is set in the order of, and the ignition intervals are set to unequal intervals. Moreover, the crank balance is set to about 50%.

As described above, in the V-type four-cylinder four-stroke engine in which the ignition intervals of the cylinders 26 ... Are unequal intervals, as shown in FIG. 4, the piston 27a of the cylinder 26a corresponding to the first crank pin 24a. And the mass of the reciprocating part including the piston 27b of the cylinder 26b corresponding to the second crank pin 24b is M _rec .
_rec , cylinder 2 corresponding to the third crank pin 24c
The mass of the reciprocating portion including the piston 27c of 6c is M _rec , the fourth
If the reciprocating unit mass comprising a piston 27d of the cylinder 26d corresponding to the crank pin 24d of the m _rec, the crank radius r, its angular velocity omega, the first crank pin 24
The distance L between a and the fourth crank pin 24d, the distance l between the second crank pin 24b and the third crank pin 24c
If so, the primary inertia couple is as shown in FIG. That is, when the crank balance is 50%, the primary inertial force generated by the first cylinder 26a is (1/2) m _rec
-Rω ² , the primary inertial force generated by the second cylinder 26b is (1/2) M _rec · rω ² , and the primary inertial force generated by the third cylinder 26c is (1/2) M _rec・ Rω ² , 4th
The primary inertial force generated by the cylinder 26d is (1 /
2) It is represented by m _rec · rω ² .

From the balance of the moments of the mass of the reciprocating portion of the cylinder, (1/2) m _rec · rω ² × L
And (1/2) M _rec · rω ² × l are equal, the primary inertial force generated by the engine is completely canceled. That is, the mass M _rec of the reciprocating portions of the second and third cylinders 26b and 26c is set to the first and fourth cylinders 26a and 26d.
By making each reciprocating part mass of m _rec larger than 1
The secondary inertial couple is canceled. Or at least M
_{According to rec} −m _rec , the primary inertial couple is reduced.

Next, as described above, the mass M _rec of each reciprocating part of the second and third cylinders 26b and 26c is made larger than the mass m _rec of each reciprocating part of the first and fourth cylinders 26a and 26d. An example will be described. In the specific example, the piston pin 28 is used for easy adjustment and easy processing.
This is achieved by changing the mass of the first and fourth piston pins 28a and 28d.
As a general hollow piston pin 28A as shown in (A),
The second and third piston pins 28b and 28c are shown in FIG.
The solid piston pin 28B as shown in (B) or the thick hollow piston pin 28C as shown in FIG. 6 (C) is used.

According to the outboard motor having the above structure,
On the upper part of the outboard motor main body 20, left and right cylinder axis C, V of C
Since the V-type 4-cylinder 4-stroke engine 21 having a mold expansion angle of less than 90 ° is mounted, not only is it advantageous in terms of fuel consumption and emission control by the 4-stroke engine, but also the conventional V-type 6-cylinder 4 Compared to an outboard motor equipped with a stroke engine, the number of parts is reduced and the weight is reduced, and the engine can be compactly housed in terms of height. Moreover, in the above-described V-type 4-cylinder 4-stroke engine 21, the relative angle between the first crank pin 24a and the second crank pin 24b is π−.
As 2θ, the phase angle between the first crank pin 24a and the third crank pin 24c is 360 °, and the phase angle between the second crank pin 24b and the fourth crank pin 24d is 36 °.
Set to 0 ° and crank balance of 50%,
Since each reciprocating part mass M _rec of the second and third cylinders 26b and 26c is set to be larger than each reciprocating part mass m _{rec of} the first and fourth cylinders 26a and 26d, the first cylinder 26a and the second cylinder 26a Cylinder 26b, third cylinder 2
6c and the fourth cylinder 26d, the primary inertial force of the engine is basically not generated even if the ignition intervals are unequal intervals, and the primary inertial couple has an equal ignition interval. It is still smaller than that of the 180 ° crank, and the fluctuation component of the reaction force of the driving torque can be made smaller than that of the 180 ° crank.

Therefore, when the V-type 4-cylinder 4-stroke engine 21 is mounted on the outboard motor, it is possible to suppress the transmission of vibrations to the hull without providing a primary couple balancer. The crankcase 31 can be compactly housed. Due to the above, the outboard motor part that enters the inside of the hull when tilting up is compact,
It is possible to provide an advantageous outboard motor even when two aircraft are used. Further, since the primary inertial couple direction generated by the engine is the V-type 4-cylinder 4-stroke engine 21 generated in the plane orthogonal to the thrust direction of the outboard motor, it is transmitted to the hull.
It is possible to almost eliminate the influence of the secondary inertial couple, and it is possible to further reduce the transmission of vibration. When the crankshaft 22 is rotated in the opposite direction, the first, fourth, third,
The ignition order may be the order of the second cylinder.

By the way, in the embodiment, the engine mounted on the outboard motor is used. However, the application example of the engine is not limited to the embodiment but may be arbitrary, and a specific detailed structure or the like may be applied. Of course, it can be changed appropriately.

[0019]

As described above, according to the V-type 4-cylinder 4-stroke engine of the present invention, the relative angle of the first and second crankpins is π-2θ (θ: V-type expansion angle of the cylinder axis). Then, set the phase angle of the first and third crank pins to 36
0 °, 360 ° phase angle of second and fourth crankpin
Since the reciprocating mass of each of the second and third cylinders is made larger than the reciprocating mass of each of the first and fourth cylinders, even if the ignition intervals of each cylinder are unequal, the primary inertia The force can be canceled or the primary inertia couple can be reduced according to the difference in the mass of the reciprocating portions of the cylinders. Therefore, it is suitable for mounting on the outboard motor. Further, according to the second aspect, the adjustment is simple because the adjustment is performed for a single item by changing the mass of the piston pin. Moreover,
According to the third aspect, since the piston pin is processed, it is easy to process.

[Brief description of drawings]

FIG. 1 is a vertical sectional side view schematically showing an example of application of a V-type 4-cylinder 4-stroke engine to an outboard motor according to the present invention.

FIG. 2 is a cross-sectional view of the V-type 4-cylinder stroke engine portion.

FIG. 3 is a plan view illustrating a crankpin phase.

FIG. 4 is a perspective view of the same.

FIG. 5 is a diagram for explaining the balance of moments of the cylinder reciprocating portion mass.

FIG. 6 is a perspective view showing a piston pin processing example.

[Explanation of symbols]

21 ... V-type 4-cylinder 4-stroke engine, 22 ... Crank shaft, 24 ... Crank pin, 25 ... Crank web, 2
6 ... Cylinder, 27 ... Piston, 28 ... Piston pin,
29 ... connecting rod, C ... cylinder axis.

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[Procedure amendment]

[Submission date] March 23, 1993

[Procedure Amendment 1]

[Document name to be corrected] Drawing

[Name of item to be corrected] Figure 1

[Correction method] Change

[Correction content]

[Figure 1]

Claims (3)

[Claims] 1. A V-type 4-cylinder 4-stroke engine in which the cylinder axis is expanded into a V-shape and the ignition intervals of the cylinders are unequal, and the crankpin of the crankshaft is the V-shape of the cylinder axis. When the expansion angle is θ, the relative angle of the first and second crank pins from the one end side is π−2θ.
Then, the phase angles of the first and third crank pins are set to 360
And the phase angle of the second and fourth crankpins is 360 °, and the mass of each reciprocating part of the cylinder corresponding to each crankpin is the same as the mass of each reciprocating part of the second and third cylinders. The V-type 4-cylinder 4-stroke engine is characterized in that the mass of each reciprocating portion of the cylinder 4 is made larger. 2. The V-type four-cylinder according to claim 1, wherein masses of piston pins of the second and third cylinders are larger than masses of piston pins of the first and fourth cylinders. 4-stroke engine. 3. The piston pins of the first and fourth cylinders are hollow, and the piston pins of the second and third cylinders are solid or more than the piston pins of the first and fourth cylinders. The V-type 4-cylinder 4-stroke engine according to claim 2, wherein the V-type 4-cylinder 4-stroke engine is thick and hollow.