JPS59115451A - Reciprocating internal combustion engine - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a reciprocating internal combustion engine, and more particularly to a reciprocating internal combustion engine with an improved coupling structure between a piston and a connecting rod.

In commonly used reciprocating internal combustion engines, a piston in a cylinder is pivotally connected to the small end of a connecting rod through a piston pin, with each part of the piston in a fixed position relative to the piston pin.

Therefore, the combustion chamber volume (the volume of the chamber formed by the cylinder head, intake and exhaust valves, and the upper surface of the piston head when the piston is located at the top dead center) is always constant.

On the other hand, the air-fuel mixture drawn into the cylinder during the intake stroke of the reciprocating internal combustion engine flows into the cylinder with a slight inflow delay relative to the downward movement of the piston due to its inertia and throttle resistance. Inflow. This delay in the inflow of the air-fuel mixture causes a reduction in the filling rate when the piston speed is high, that is, when the reciprocating internal combustion engine is operating at high speed.

When the piston speed is low, that is, when the reciprocating internal combustion engine is operating at low speed, the closing timing of the intake valve is delayed, resulting in a decrease in the filling rate.

The decrease in the filling rate directly causes a decrease in the shaft output of the reciprocating internal combustion engine.

As is clear from the full-throttle performance curve a of a typical reciprocating internal combustion engine in Fig. 1, the shaft output of the reciprocating internal combustion engine is
It shows a maximum at R, and exhibits a characteristic that decreases when the engine speed R is smaller or larger than this engine speed R.

In order to compensate for the shortcomings in the shaft output of reciprocating internal combustion engines that exhibit the above-mentioned full-throttle performance curve a, a supercharger has been proposed that blows excess air-fuel mixture into the cylinder. This supercharger certainly has the effect of increasing the shaft output of the reciprocating internal combustion engine, as shown by the full-throttle performance curve in FIG.

However, according to the full-throttle performance curve of the turbocharger in Figure 1,
On the side where the engine speed is higher, this has the effect of expanding the range in which the shaft output is maximum, but on the side where the engine speed is lower, it does not have the effect of improving the shortcoming that the shaft output drops rapidly.

Furthermore, since the reciprocating internal combustion engine is equipped with a supercharger, the structure of the reciprocating internal combustion engine becomes complicated, and the manufacturing cost thereof also increases.

SUMMARY OF THE INVENTION An object of the present invention is to provide a reciprocating internal combustion engine that does not have a complicated configuration and is therefore inexpensive to manufacture.

Another object of the present invention is to provide a reciprocating internal combustion engine that improves shaft output at each engine speed.

Another object of the present invention is to provide a reciprocating internal combustion engine in which the pressure of the air-fuel mixture in the combustion chamber is maintained substantially constant or the pressure fluctuations of the air-fuel mixture are alleviated even when the filling rate is reduced fc. That's true.

Another object of the present invention is to provide a reciprocating internal combustion engine that can more completely exhaust combustion gases during the exhaust stroke.

A feature of the present invention for achieving these objects is that in a reciprocating internal combustion engine, a piston and a connecting rod consisting of a piston head and a piston body are arranged so that at least a part of the piston is within a certain range along the longitudinal axis of the piston. A compression spring is interposed between the piston head and the connecting rod, and the compression spring fills the combustion chamber volume. This is done so that it is adjusted according to the rate.

Therefore, according to the reciprocating internal combustion engine according to the present invention, even if the filling rate in each cycle fluctuates up or down with respect to the standard filling rate for the reciprocating internal combustion engine of the present invention, especially when it decreases, the mixture in the combustion chamber The air pressure is automatically adjusted within a set range to become the standard mixture pressure for the reciprocating internal combustion engine of the present invention. That is, since the reciprocating internal combustion engine according to the present invention eliminates the adverse effects of fluctuations, especially decreases, in the filling rate, it is possible to obtain a reciprocating internal combustion engine with a relatively large shaft output even in a low speed range.

Further, the reciprocating internal combustion engine according to the present invention can increase the amount of combustion gas exhausted to the outside of the cylinder by the action of the compression spring even during the exhaust stroke.

Hereinafter, preferred embodiments of the present invention will be described in detail with reference to FIGS. 2 to 5.

As shown in FIGS. 2 and 3, a piston 12 is slidably disposed within the cylinder 11 of the a-compound internal combustion engine according to the present invention. At the piston side wall,
A piston 12 is located at a diametrically opposite position of the piston cross section.
A long hole 14, which is long in the longitudinal axis direction, is formed in each case.

It is desirable that the vicinity of the inner circumferential wall 14a of these elongated holes 14 be surface treated by surface hardening or other methods to improve mechanical strength.

Both ends of a piston pin 16 are loosely fitted into the elongated hole 14, and a small end 16a of the connecting rod 16 is connected to the piston pin 16. The large end of the connecting rod 16 (see Figure 5) is
It is coupled to the crankshaft 18.

A compression coil spring 15 is interposed between the ceiling inner wall surface 12b of the piston head 12a of the piston 12 and the small end 16a of the connecting rod 16. Both ends of this compression coil spring 15 abut on the ceiling inner wall surface 12b and the small end 16a of the connecting rod 16, respectively. In addition to this, compression coil spring 1
5 always elastically urges the piston 12 toward the cylinder head 11a of the cylinder 11 within a distance within which the elongated hole 14 can move relative to the piston pin 13.

The upper surface of the piston head 12& of the piston 12 that has reached the top dead center, the inner surface of the cylinder head 11a, and the intake and exhaust valves 19
A and 19b form a combustion chamber 17 with variable volume.

In the present invention, when the piston 12 is located at the top dead center, the piston pins 1, ! 1 d! 4 to hole 14
88t of the combustion chamber 17 when it comes into contact with the upper edge (in other words, when the compression coil spring 15 is compressed to the maximum of the set range) is defined as the standard combustion chamber volume, and occupies this standard combustion chamber volume. For the reciprocating internal combustion engine according to the present invention, the pressure exhibited by the air-fuel mixture at a standard filling rate is defined as the standard combustion chamber pressure.

The spring constant of the compression coil spring 15 is equal to the standard combustion chamber pressure υ
is also selected to be slightly larger (to counteract the weight of the piston 120).

In the case of this embodiment, it is desirable that the spring constant of the compression coil spring 15 is 9/crn.

Hereinafter, the functions and effects of the reciprocating internal combustion engine will be explained with reference to FIGS. 5(a) to 5(7) in the case where the filling rate is equal to or higher than the standard filling rate.

First, as shown in Fig. 5(a)K, the piston 1
2 is pushed up and located at the top dead center at a crank angle of 0°, that is, at the start of the intake stroke.

Next, while the reciprocating internal combustion engine transitions from the state shown in FIG. 5(a) to the state shown in FIG. 5(0), the piston 12 descends from a crank angle of 0° to a crank angle of 90° to perform an intake stroke do.

As shown in FIG. 5(B), when the piston 12 has descended to a crank angle of 90°, the exhaust valve 19b is already closed and the intake valve 19a is open, so that fresh air-fuel mixture is pumped into the cylinder. It has already flowed into the interior.

Next, as shown in Fig. 5, the piston 1
2 reaches the bottom dead center at a crank angle of 180°, that is, at the end of the intake stroke.

While the reciprocating internal combustion engine transits from the state shown in FIG. 5(a) to the state shown in FIG. 5(c), that is, from the start to the end of the intake stroke, the piston 12
The piston pin 16 is pushed up to its maximum position by the restoring force of the piston pin 16.

Next, the reciprocating internal combustion engine changes from the state shown in FIG.
During the transition to the state shown in the figure), the intake and exhaust valves 19a and 19
b are both closed.

FIG. 5) shows a state in which the piston pin 13 has already left the lower end edge of the elongated hole 14 at a crank angle of 270°. The timing at which the piston pin 16 separates from the lower end edge of the elongated hole 14 depends on the filling rate.

The above-mentioned reciprocating internal combustion engine is shown in Fig. 5 (E) from the state shown in Fig. 5).
During the transition to the state of , that is, from the middle of the compression stroke to the end of the compression stroke, the piston 12 moves until the piston pin 13 comes into contact with the upper edge of the elongated hole 14 .
It is pressed down to position 6.

In other words, if the filling rate is equal to or higher than the standard filling rate, the piston 12 is located at the top dead center without being pushed up at the end of the compression stroke.

Conversely, the filling rate is the spring constant of the compression coil spring 15 and the elongated hole 1.
If p is smaller than the standard filling rate than the allowable filling rate variation range determined by the moving distance of the piston pin 16 in the piston 12 during the compression stroke, the piston 12
The piston pin 13 is pushed up against the position t until the piston pin 3 comes into contact with the lower edge of the elongated hole 14.

Further, if the filling rate is smaller than the standard filling rate within the allowable filling rate fluctuation range, the piston 12 will move the piston pin 16 between the upper and lower edges of the elongated hole 14 according to the difference between the standard filling rate and the filling rate. Piston pin 1 to the extent that it does not come into contact with any
It is pushed up against the 6 position.

The air-fuel mixture in the combustion chamber 17 is ignited near when the piston 12 reaches the top dead center in the compression stroke, and in the process of combustion of this air-fuel mixture, the reciprocating internal combustion engine changes from the state shown in FIG. 5 (e). The main expansion stroke begins in the state shown in FIG. 5 (G).

During this time, the compression coil spring 15 is compressed by the expansion pressure of the combustion gas in the hollow portion 1ib, with the piston pin 16 in contact with the upper edge of the elongated hole 14.

Finally, while the reciprocating internal combustion engine is transitioning from the state shown in FIG. 5 (g) to the state shown in FIG.

Therefore, the pressure in the hollow part 11b gradually decreases, and as the pressure in the hollow part 11b becomes smaller than the spring constant of the compression coil spring 15, the compression coil spring 15 becomes
Unloaded. As a result, until the reciprocating internal combustion engine reaches the state shown in FIG. It rises due to the resilience of 15.

Since the piston 12 can exhaust combustion gas to the outside of the cylinder 11 by the amount pushed up by the compression coil spring 15, the degree of temperature rise near the cylinder head 11 is reduced by υ compared to a general reciprocating internal combustion engine. Thereby, the life of the cylinder 11 can be extended.

In the above embodiment, if the spring constant of the compression coil spring 15 is determined so that the piston pin 13 comes to rest at the middle position of the elongated hole 14 when the filling rate becomes the standard filling rate, the filling rate becomes higher than the standard filling rate. Even when the pressure is large, the air-fuel mixture pressure in the combustion chamber 17 can be automatically adjusted to be constant.

Another embodiment of the present invention will be described below with reference to FIG. The same reference numerals are used to designate the same parts as in the previous embodiments of the present invention. In the embodiment shown in FIG. 4, the piston 20 is composed of a piston body 22 and a piston head 23, which are separate from each other. The piston body 22 and the piston head 26 are connected by a plurality of guide pins 26 that allow relative movement of a certain distance between the piston body 22 and the piston head 23.

The connecting rod 16 is connected to the piston body 2 by the piston pin 16.
It is connected to 2.

The ceiling inner wall surface 2 lobe b of the piston head 23 and the connecting rod 1
A compression coil spring 15 is interposed between the small end 16a of the spring 6 and the small end 16a of the spring 6. Both ends of the compression coil spring 15 are brought into contact with the ceiling self-suction surface 2Mb and the small end 16a of the connecting rod 16, respectively.

In the case of the embodiment shown in FIG. 4, unlike the embodiments shown in FIGS. 2 and 3, only the piston head 2 moves relative to the piston pin 1 within the range limited by the guide pin 26. do.

In the case of the embodiment shown in FIG. 4 as well, the pressure of the air-fuel mixture in the combustion chamber 17 is automatically adjusted to be approximately constant within the range set by the compression coil spring 15. The operation of this automatic adjustment is the same as the operation in the cases of FIGS. 5(a) to 5(7), and therefore will not be described in detail again.

[Brief explanation of drawings]

FIG. 1 is a shaft-out Kerr rotational speed curve diagram showing the full-throttle performance of a conventional reciprocating internal combustion engine, FIG. 2 is a partial vertical sectional view of a reciprocating internal combustion engine according to an embodiment of the present invention, and FIG. I- in Figure 2
4 is a longitudinal sectional view of a reciprocating internal combustion engine according to another embodiment of the present invention, and FIG. 5 is an explanatory diagram of the operation of the reciprocating internal combustion engine according to the embodiment of FIG. 2. 12... Piston, 12a... Piston head, 1
3... Piston pin, 14... Long hole, 14a...
Inner peripheral wall, 15... Compression coil spring, 16... Connecting rod, 17... Combustion chamber, 20... Piston, 22...
Piston body, 23...Piston head, 26...
guide pin. Figure 1

Claims (1)

[Claims] (1) In a reciprocating internal combustion engine, a piston consisting of a piston head and a piston body and a connecting rod move relative to each other within a certain range along the longitudinal axis of the piston. The combustion chamber is connected by a piston pin that engages with the piston body, and a compression spring is interposed between the piston head and the connecting rod, and the compression spring adjusts the volume of the combustion chamber according to the filling rate. A reciprocating internal combustion engine. (2. In the reciprocating internal combustion engine according to claim 1, a long hole is formed in the piston body at both opposing positions in the longitudinal axis direction of the piston, and the piston pin is inserted into the long hole. A reciprocating internal combustion engine that is loosely fitted. (3) A reciprocating internal combustion engine according to claim 2, wherein a quenched hardened layer is formed near the inner peripheral wall of the elongated hole. ) A reciprocating internal combustion engine according to claim 1, wherein a part of the piston is a piston head. (5) A reciprocating internal combustion engine according to claim 4, wherein the reciprocating internal combustion engine A reciprocating internal combustion engine in which a guide pin is interposed between a piston head and the piston body for guiding relative movement between the piston head and the piston body. (6) Permitted scope of claim 1 The reciprocating internal combustion engine according to any one of items 1 to 5, wherein the compression spring has a spring constant of approximately 12.6 to 9/crn.