JP2772769B2 - V-type 8-cylinder engine - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a V-type eight-cylinder equally-spaced four-cycle internal combustion engine having a bank angle other than 90 degrees.

[0002]

2. Description of the Related Art Generally, in a V-type multi-cylinder internal combustion engine such as a V-type six-cylinder or an eight-cylinder, their bank angles are 60 degrees and 90 degrees.
Having a certain value such as degree is considered to be oscillatingly advantageous and has become practical.

On the other hand, recently, a V-type six-cylinder engine having a narrow bank angle of 10 degrees or less has been developed and mounted on an actual vehicle. However, this type of engine still has an unbalanced moment, and is dissatisfied with vibration.

[0004] For details of the above points, see "Mechanical Engineering Handbook", "Automotive Engineering Handbook" and "Conference papers and research reports".
And Japanese Patent Application Laid-Open No. 61-41034.
No. and U.S. Pat. No. 3,308,680 and N
o. No. 3,978,828.

[0005]

In the V-type eight-cylinder four-cycle internal combustion engine, when the bank angle is not 90 degrees, the primary unbalance of the reciprocating and rotating parts is larger than when the bank angle is 90 degrees. It is considered that the moment increases and the engine vibration increases. For this reason, V-type eight-cylinder engines having a bank angle other than 90 degrees are hardly developed. However, if the bank angle is fixed at 90 degrees in this way, the space and design around the engine are also fixed, which makes it impossible to design a versatile vehicle.

Accordingly, it is an object of the present invention to set the bank angle to 90
Even if it is set to a degree other than the degree, the bank angle is not much different from the one with a bank angle of 90 degrees. Therefore, by providing a V-type eight-cylinder engine that can have a degree of freedom in car design. is there.

[0007]

According to the V-type eight-cylinder engine of the present invention, the bank angle is set to about 53 °, about 37 °, about 143 °, or about 127 °, and the couple weight is set with respect to the x-axis. Are mounted on the crankshaft with a mounting phase of θ ₀ + π, and the ratio of the magnitude of the couple weight is such that the bank angle is about 5
3/4 or about 127 ° (4/5) 10 ^1/2
m _rec and bank angle about 37 ° or about 143 °
V-type eight-cylinder engine, wherein (3/5) is set to 10 ^1/2 m _rec .

Here, the x-axis indicates the direction of the center line of the V-shape,
And θ ₀ is a phase constant whose magnitude is about 5
45 ° for 3 ° or about 127 °, 90 ° for a bank angle of about 36 °, 0 ° for a bank angle of about 143 °, and m _rec = m _p + ( 1-c _p)
a m _r (where, m _p and m _r is the mass of the piston and connecting rod, also c _p is the piston pin center and the connecting rod between the center of the crank pin length of piston pin and L the length between the center and the center of gravity of the connecting rod is L _P / L in the case of the L _P).

[0009]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Referring to the accompanying drawings, a description will be given of a V-type eight-cylinder engine according to an embodiment of the present invention, together with a design theory thereof.

[0010] In order to achieve the above object, the present invention provides:
First, a dynamic analysis is performed on the vibrating force and the vibrating moment generated in the V-type eight-cylinder engine, and the bank angle that can be theoretically established is pursued using the conditions for reducing the vibrating moment of the V-type engine. Has achieved the development of an engine having exactly the same vibratory performance as a conventional V-type 8-cylinder 4-cycle internal combustion engine.

(1) Basic Theory i) Motion and Symbol of Single-Cylinder Engine In a reciprocating multi-cylinder engine, a point on the crankshaft at the center of the engine is defined as an origin O, and the crankshaft is located on a horizontal plane including the z-axis and y-axis.
Consider a rectangular coordinate system O-xyz in which the axis and the movement direction of the piston are parallel to the xy plane. The direction of movement of the piston makes an angle of α with the x axis in a V-type engine, but α = 0 in an in-line multi-cylinder engine.

Now, consider the movement of a single cylinder in which the direction of movement of the piston coincides with the x-axis as shown in FIG. The center of the piston pin and the crank pin is O _P , C, the center of gravity of the connecting rod is G, the radius of the crank is r, the length of the connecting rod is L, G
Let the length between C be L _c and the length between GO _{P be} L _P. The masses of the piston and the connecting rod are m _p and _mr , the rotation angle of the crank is θ, and the angle between the connecting rod and the movement direction of the piston is δ,
r / L = λ, and L _P / L = c _P. The sign of the angle is x
The clockwise direction of the z-axis is defined as positive with the axis as the base line. Relative to the crankshaft, by adding balancing weights previously mass m _r (L _P / L) in the center C and symmetrical position Q of the crank pin, thereby reducing the vibratory force of the y-axis direction. At this time, the inertial force F _x (θ) generated in the x-axis direction is expressed by the following equation.

[0013]

(Equation 1)

Ii) In-line four-cylinder constituting a V-type eight-cylinder engine In general, a V-type engine has two in-line engines arranged in a V-shape,
It has a common crankshaft. In the case of a V-type eight-cylinder engine (hereinafter referred to as a V8-type engine), an in-line four-cylinder is a constituent element. Here, first, a cylinder arrangement of in-line four cylinders will be considered. Table 1 shows two standard types of in-line four cylinder crank phases.

[0015]

[Table 1]

In this table, J is the cylinder array number.
In the type (a), the pitch is not generated because the crank is arranged symmetrically with respect to the origin O.
However, an inertial force F _x (θ) is generated in the x-axis direction, and is expressed as follows.

[0017]

(Equation 2)

From this, F _x (θ) is given by the equation (2),
It can be calculated using (3). Next, the cylinder arrangement of the in-line four cylinders of the type (b) will be considered. Table 1
And G (θ) and F (θ) of the sequence number J are represented as G _J and F _J, and _J represents i, j, ν, and μ. i, j,
The number of combinations of arrays of ν and μ is 4! It is. At this time, if indicated the pitching moment about the y-axis acting on the engine as M _y, M _y is expressed by the following equation.

[0019]

(Equation 3)

From this, only the first-order terms are included in parentheses.
In the pitching moment of the equation (11), only the first-order periodic function remains. That is, such a combination system establishes a V8 type engine in which no vibration moment occurs.

Table 2 shows that the series 4
It shows eight types of cylinder arrangement of cylinders.

[0022]

[Table 2]

(2) Cylinder arrangement theory of a V-type 8-cylinder engine a. FIG. 2 shows two series engines R using the same coordinate system as FIG.
₁ and R ₂ are diagrams illustrating a V-type engine. The directions of piston movement of R ₁ and R ₂ are X ₁ and X ₂ axes, and the angles between them and the x axis are α ₁ and α ₂ . α ₁ and α ₂ are positive when clockwise on the z axis. Assuming that the bank angle of the V-type engine is α ₀ , the following equation holds.

Α ₀ = α ₂ −α ₁ (14) In FIG. 2, P ₁ and P ₂ denote the centers of the piston pins of the respective cylinders, C ₁ and C ₂ denote the centers of the crank pins,
Q ₁ and Q _{2 respectively} indicate positions symmetrical with the center of the crankpin where the balance weight is added.

FIG. 3 is a crank configuration diagram of a V8 type engine. The crank phase of one row of the V type is θ, θ + π / 2,
When θ + π and θ−π / 2, they are numbered 1, 2,
3, 4 and the other columns are (1), (2), (3),
(4).

FIG. 3 (b) shows that x generated in the V8 engine
The inertial forces F _x (θ) and F _y (θ) in the axial and y-axis directions are expressed by the following equations.

[0027]

(Equation 4)

For _My02 , the subscripts are (i),
(J), (ν) and (μ) will be rewritten and expressed by the same formula.

Here, R ₁ and R ₂ in FIG. ₂ are configured as an array such as two sets of in-line four cylinders in FIG. FIG.
(A) shows that the origin of each row of R ₁ and R ₂ is shifted in the crankshaft direction by s ₀ . However, since the sum of the vibrating forces in each row is affected only by the fourth term or higher, the deviation is not considered for the vibrating moment.

B. Cylinder arrangement of V-type eight-cylinder engine The cylinder arrangement of in-line four-cylinders constituting the V8-type engine showed that the combinations shown in Table 2 were basic. In the V8 engine, since they are arranged in two rows, the total number of combinations is 64.

Table 3 shows the 64 combinations.

[0032]

[Table 3]

The upper row of each combination in the table shows the cylinder arrangement in the first row, and the lower row shows the cylinder arrangement in the second row. Each row in the table is obtained by changing the cylinder arrangement in the lower row sequentially while keeping the cylinder arrangement in the upper row constant. For these combinations, the relationship between the generated vibration moment and the optimum bank angle must be examined in detail.

(3) Exciting Moment and Bank Angle In the calculation of the exciting moment in each of the combinations shown in Table 3, ω was treated as a constant as in the conventional method. As a result of the calculation, it was found that the characteristics of the excitation moment can be arranged for each row in Table 3. Therefore, each row in Table 3 is changed to Case
In the following, the results of analysis are shown for the combinations in the first column of each Case.

[0035] CaseI sequence of this case is as follows.

[0036] The first row 1 2 4 3 second column (4) (1) (3) (2) this sequence, first, when obtaining the M _y01, M _y02 of two rows from equation (17), the following Is represented as

[0037]

(Equation 5)

[0038]

(Equation 6)

Next, when the same calculation is performed for α ₀ = −π / 2, an inverted grinding motion occurs. Therefore, M _y ^*, the disappearance of M _x ^*, require reversal type of balance shaft, not practical.

FIG. 4 shows an example of the configuration of a Case I crank. FIG. 4A shows the shape and phase of the crank, and FIG. 4B shows the disappearance of the vibrating moment.

[0041] CaseII sequence of this case is as follows.

First column 1 2 4 3 Second column (4) (3) (1) (2) When M _y and M _x are obtained in the same manner as in Case I, the following equation is obtained.

[0043]

(Equation 7)

Here, θ ₀ = −π / 4. From this, it becomes precession of Seitengata, like Casei, the balance weight, M _y ^*, M _x ^* can be eliminated. Α _{0 in} this case is a practical value.

Next, when the same calculation is performed with α ₀ = − | cos ⁻¹ (3/5) |, in this case, an inverted balance shaft is required, which is not practical.

FIG. 5 shows an example of the configuration of a Case II crank. FIG. 5A shows the shape and phase of the crank, and FIG. 5B shows the disappearance of the vibrating moment.

[0047] CaseIII sequence of this case is as follows.

First column 1 2 4 3 Second column (3) (2) (4) (1) Similarly, M _y and M _x are obtained, and the conditions for making them circular circular motions are as follows. Then, the following equation is obtained.

[0049]

(Equation 8)

FIG. 6 shows an example of a Case III crank configuration. FIG. 6A shows the shape and phase of the crank, and FIG. 6B shows the disappearance of the vibrating moment.

[0051] CaseIV sequence of this case is as follows.

1st row 1 2 4 3 2nd row (3) (4) (2) (1) Similarly, when conditions for a circular grinding motion are obtained, the following equation is obtained. cos α ₀ = 1 (41) From this, α ₀ = 0, and the engine is an in-line eight-cylinder engine.

[0053] CaseV sequence of this case is as follows.

First column 1 2 4 3 Second column (1) (2) (4) (3) By the same calculation, the following equation is obtained for α ₀ .

Cos α ₀ = −1 (42) From this, α ₀ = π. In this case, the engine is a horizontally opposed 8-cylinder engine.

Case VI The sequence in this case is as follows.

First column 1 2 4 3 Second column (1) (4) (2) (3) By the same calculation, the following equation is obtained for α ₀ .

[0058]

(Equation 9)

The sequence in Case VII is as follows.

First column 1 2 4 3 Second column (2) (1) (3) (4) In this case, similarly, the following equation is obtained for α ₀ .

[0061]

(Equation 10)

Case VIII The sequence in this case is as follows.

First column 1 2 4 3 Second column (2) (3) (1) (4) When α ₀ is obtained by the same calculation, α ₀ = π / 2, and the same result as Case I is obtained. .

(4) V8 type engine and bank angle As described above, in the V8 type engine, the terms of the second order and higher are eliminated because of the combination of in-line four cylinders, and the primary terms can also be eliminated by the balance weight. all right.
These features are classified into Case I to VIII, and the bank angles obtained in each Case are summarized as follows.

The V8 engine has two types having a 90 ° bank angle, about 53 ° type, about 37 ° type, about 143 ° type,
There are one type each of about 127 ° bank angle, horizontal facing type, and series type. With the exception of the horizontally opposed type and the series type, the unbalanced moment of the engine can be eliminated by adding a balance weight to the crankshaft, similarly to the conventional 90 ° V type. Among them,
The about 53 ° and about 37 ° types can be said to be newly obtained practical bank angles.

[0066]

[Equation 11]

[0067]

According to the engine configuration of the present invention, the bank angle can be set to a practical narrow angle or a wide angle, and the degree of freedom of design such as downsizing of the engine is increased.

With regard to the V-type eight-cylinder engine, 64 kinds of arrangement systems capable of extinguishing the pitching and yawing vibration moments by weight were examined dynamically. As a result, regarding the bank angle, in addition to the 90 ° V type, the horizontally opposed type, and the in-line type which are currently in practical use, new about 53 °, about 37 °, about 143 °, and about 127 ° V type eight-cylinder engine are used. It turns out that it holds. Also,

(Equation 12)

As described above, the V-type eight-cylinder engine is a conventional nine-cylinder engine.
It was found that there are four types of engines with different angles other than the 0 ° V type.

[Brief description of the drawings]

FIG. 1 is a view for explaining the movement of a single cylinder in which the direction of movement of a piston coincides with the x-axis.

FIG. 2 shows the use of the same coordinate system as in FIG.
₁ and R ₂ are diagrams illustrating a V-type engine.

FIG. 3 is a crank configuration diagram of a V8 engine.

FIG. 4 is a diagram for explaining a crank of Case I, where (a) shows the shape and crank phase of the crank,
(B) is a diagram showing the disappearance of the vibrating moment.

5A and 5B are diagrams for explaining a Case II crank; FIG. 5A shows a crank shape and a crank phase;
(B) is a diagram showing the disappearance of the vibrating moment.

6A and 6B are diagrams for explaining a Case III crank. FIG. 6A is a diagram illustrating a shape and a crank phase of the crank, and FIG. 6B is a diagram illustrating disappearance of the vibrating moment.

[Explanation of symbols]

O _P ... piston pin center, C ... of the crank pin center,
G ... center of gravity of the connecting rod, r ... crank radius, L ... length of the connecting rod, L _c ... length between GC, L _P ... GO _P between the length of, theta
… Crank rotation angle, δ… Angle formed by the connecting rod with the movement direction of the piston, α ₀ … Bank angle, Q… Crank pin center C
And symmetrical position.

Claims (1)

(57) [Claims] 1. A bank angle of about 53 °, about 37 °, about 14
Set at 3 ° or about 127 ° and the couple weight is x
It is attached to the crankshaft with an attachment phase of θ ₀ + π with respect to the shaft, and the ratio of the magnitude of the couple weight is (4/5) when the bank angle is about 53 ° or about 127 °.
10 ^1/2 m _rec to, also V-type 8-cylinder engine, characterized in that when the bank angle is approximately 37 ° or approximately 143 ° is set (3/5) to 10 ^1/2 m _rec. Where x
The axis indicates the centerline direction of the V-shape, and θ ₀ is the phase constant, the magnitude of which is about 53 ° or about 127 °.
45 ° for 9 ° and 9 for a bank angle of about 36 °
0 °, for the bank angle of approximately 143 ° is 0 °, also a _{m rec = m p + (1} -c p) m r ( here,
The mass of m _p and m _r is the piston and connecting rod, also c _p is the center and the center of gravity of the connecting rod length of the connecting rod is L piston pin between the centers of the crank pins of the piston pin L _P / L where the length between them is L _P ).