JPH0253651B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to an improvement of a V-type internal combustion engine, and particularly to one in which higher-order residual unbalanced inertia force is minimized.

(Prior Art) A so-called phase crank (Japanese Unexamined Patent Publication No. 113646/1983) has been developed in which the crank pin of a V-type internal combustion engine is provided with a predetermined deflection angle to reduce the primary residual unbalanced inertia force to zero.

In this prior art, as shown in Fig. 6, the primary residual unbalanced inertia force becomes 0 when the crankshaft overbalance ratio δ and the crank pin relative angle β are β = 2α + 180° δ = 0.5.
There is a problem in that the higher-order residual unbalanced inertial force does not necessarily reach its minimum value.

(Objective of the Invention) An object of the present invention is to provide a V-type internal combustion engine that can bring the residual unbalanced inertia close to a minimum value, even including higher-order residual unbalanced inertia.

(Structure of the Invention) The present invention is characterized in that when the included angle α between one cylinder row and the other cylinder row, where both the reciprocating system mass and the rotating system mass are equal, is less than 60 degrees, around 40 degrees, only the first-order unbalanced inertia force is applied. When the deviation of the crankshaft overbalance rate relative to the case of 0 is △δ, the deviation rate of the crank pin relative angle β is △β, and the included angle is α, β = 2α + 180° + △β δ = 0.5 + △ By adjusting the overbalance ratio δ and the crank pin relative angle β expressed as δ (△β>0, △δ>0) to values exceeding 0, the first order higher order V characterized by minimizing the residual unbalanced inertia including
It is an internal combustion engine.

(Example) In FIG. 1 showing the case where the present invention is applied,
2 is the front cylinder and 4 is the rear cylinder. r
indicates the crank arm length, and L indicates the connecting rod length.

The overbalance rate δ is expressed as δ=n/m, where m is the mass of the reciprocating system such as the piston and piston pin, and n is the mass of the rotating system such as the counter balancer 6 and the crank pin 8. The rotating system mass n is the mass of the counter balancer 6 and the crank pin 8, which are located at opposing positions with the crankshaft center O in between and whose centrifugal forces act in directions that cancel each other out.

The deviation of the overbalance rate when only the first-order unimpinged inertia force is 0 and when the residual unimpeded inertial force including higher-order ones is the minimum value is △
If δ, the overbalance rate δ is δ=0.5+△δ...(1).

Similarly, the relative angle β between the front cylinder 2 and the rear cylinder 4 is β=2α+180°+Δβ (2) where the deviation is Δβ and the cylinder angle is α.

In Fig. 1, the resultant unimpulsive inertial force F when the crank rotation angle is θ is the unimpulsive inertial force component in the x direction.
If the unimpinged inertial force component in the Fx and y-axis directions is Fy, it is expressed as F=√ ² + ² ...(3). At this time, Fx and Fy are reciprocating system mass m, crank arm length r, and crankshaft angular velocity ω, then Fx = (Fr ¹ + Fr ² ) cosα−δmrω ²
(cosθ+cos(β−θ))……(4) Fy=(Fr ¹ −Fr ² )sinα−δmrω ²
(sinθ−sin(β−θ))……(5) Fr ¹ and Fr ² in equations (4) and (5) are Fr ¹ = mrω ² [cos (θ-α/2) + λcos2 (θ-α /2
)+sin(θ−α/2)・(λsin(θ−α/2)−ξ)
³ +ξsin(θ−α/2)/(1−(λsin(θ−
α/2)-ξ) ² ) ^3/2 ]...(6) Fr ₂ = mrω ² [cos(θ+α/2-β)+λcos2(θ+α
/2-β)+sin(θ+α/2-β)・(λsin(θ+α/2-β)+ξ) ³ −ξsin(θ+α/2-
β)/(1-(λsin(θ+α/2-β)-ξ) ² ) ^3/2
]...(7) However, λ=r/L, ξ=ε/L.

At this time, the characteristics of the deviations △β and △δ with respect to the included angle α at which the maximum value of the resultant inertial force F becomes the minimum are calculated by setting r = 36 mm, L = 124 mm, and ε = 0, and the graph shown in Fig. 2 is obtained. get. Therefore, if the residual unimpingement inertia force F is calculated by selecting the optimal △β and △δ for any included angle α, only the first-order unimpingement inertia force becomes 0 in the range α < 60°. It can be seen that when the residual unimpeded inertia force in this case is taken as 100%, the residual unimpeded inertial force F is reduced by selecting the optimal values of Δβ and Δδ.

Next, when α = 45°, r = 36 mm, L = 124 mm, and ε = 0, the overbalance rate δ and coefficient K = calculated by changing the crank pin relative angle β
The relationship of mrω ² is shown in Figure 3. Figures 3 and 2
From the figure, it can be seen that when the included angle α is 45°, the coefficient K becomes the minimum when δ=0.53 and β=280°.

(Effects of the Invention) As explained above, according to the present invention, the deviation of the overbalance rate δ of the crankshaft relative to the case where only the first-order unimpingement inertia force is 0 is calculated as △δ, and the deviation of the crankpin relative angle β is calculated as Δδ. △
Since δ and Δβ are selected, the residual unimpulsive inertial force F can be reduced. Moreover, it is not necessary to change the structure of the V-type engine, and the deviations △δ, △β
Since the residual unimpingement inertia force F is reduced only by selecting , it is extremely easy to implement. In other words, in the present invention, we have discovered that there is a position and balance ratio where the minimum vibration is obtained at a position different from the equation β = 2α + 180°, and that the maximum vibration is at a cylinder relative angle (cylinder included angle α) of 60 degrees. Based on the analysis result that the effect is greatest when the cylinder relative angle is less than 40 degrees, the deviation △δ of the overbalance ratio δ and the deviation △β of the crankpin relative angle β are set to 0. is set to a value that is different and exceeds 0, and as a result, the first-order unimpulsive inertia force does not become zero, but the residual unimpulsive inertia force including the first-order higher order can be minimized. It is.

(Another embodiment) (1) When the front cylinder 2 and the rear cylinder 4 are arranged outward by an offset amount ε as shown in FIG. 4, the offset amount ε=0 as shown in FIG. The minimum value of the maximum value of the residual unimpingement inertia force F can be made smaller than the case of FIG.

(2) The present invention is not limited to even-numbered V-type engines in which the number of cylinders in one cylinder row and the other cylinder row are equal; if the reciprocating system mass and the rotating system mass of both cylinder rows are equal to each other, for example, Odd number cylinder V with 2 cylinders and 1 cylinder in the rear cylinder row
It can also be applied to shaped engines.

[Brief explanation of the drawing]

Fig. 1 is a structural diagram of a V-type two-cylinder engine to which the present invention is applied, and Fig. 2 shows the cylinder angle of the engine shown in Fig. 1, the residual unimpingement inertia force, the deviation of the overbalance ratio, and the relative angle of the crankpin. Graph showing the deviation characteristic, FIG. 3 is a graph showing the overbalance rate-coefficient characteristic, FIG. 4 is a structural diagram showing another embodiment of the present invention, and FIG. 5 is the offset amount in the case of FIG. 4. - A graph showing the minimum value of the maximum value of the residual unimpulsive inertia force F, the overbalance ratio, and the crank pin relative angle characteristics. FIG. 6 is a structural diagram showing a conventional example. 2...Front cylinder, 4...Rear cylinder, 6...Counter balancer, 8...Crank pin.

Claims (1)

[Claims] 1. The included angle α between one cylinder row and the other cylinder row is 60, in which both the reciprocating system mass and the rotating system mass are equal.
At around 40 degrees, only the first-order unbalanced inertia force is 0.
When the deviation in the overbalance rate of the crankshaft is △δ, the deviation in the crank pin relative angle β is △β, and the included angle is α, then β=2α+180°+△β δ=0.5+△δ (△β>0, △δ>0) The overbalance rate δ and crank pin relative angle β, which are expressed as V characterized by minimizing the included residual unbalanced inertia force
internal combustion engine.