JP2504232Y2 - Intake device for 2-cycle engine - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial application] The present invention relates to a reed valve type intake device applied to a two-cycle engine.

[Conventional technology]

FIG. 6 shows a reed valve 2 arranged in the intake passage 1
The cycle engine is shown.

As shown in FIG. 7, the reed valve 2 has a pair of valve seats in which the intake downstream sides (the left side in the figure) are connected to each other.
The valve seats 3 and 3 are provided with leads 5 and 5 which cover the vent holes 4 and 4, respectively.

When the piston of the engine rises, the negative pressure generated in the crankcase causes the reeds 5, 5 of the reed valve 2 to deform and move from the closed position shown by the solid line to the open position shown by the chain line. The air-fuel mixture from the carburetor that is not installed is supplied into the crankcase through the ventilation holes 4, 4.

[Problems to be solved by the device]

In order to increase the output of the engine, the above reed valve 2
The area of the ventilation hole 4 may be increased. However, in this way, although the output in the high engine speed range is improved, the combustion of the engine in the low engine speed range is not smoothly performed and the output is reduced.

In view of such a situation, an object of the present invention is to provide an intake system for a two-cycle engine that can improve the output characteristics of the engine regardless of its rotational speed range.

[Means for solving the problem]

The present invention provides a valve seat block having a V-shaped side surface and upper and lower surfaces forming an upper valve seat and a lower valve seat, respectively, a mounting frame integrally formed along a base end peripheral edge of the valve seat block, An upper lead that opens and closes a vent hole provided in the upper valve seat and a lower lead that opens and closes the vent hole toward the lower valve seat are provided, and the upper lead is formed of a magnetic material and is provided on the upper valve seat. A magnetic path for applying a magnetic attraction force to the upper lead is formed, and a reed valve in which a coil forming an electromagnet together with the magnetic path is attached to the mounting frame, and a rotation for detecting the engine speed. The coil is energized when the engine speed detected by the engine speed detection means and the engine speed detection means indicates a preset low speed range value. It is characterized in that it comprises a magnet control means.

[Action]

In a state where the engine speed is in the low speed range preset, the upper lead is forcibly attracted to the upper valve seat by the magnetic attraction force, and as a result, the intake amount is reduced.

〔Example〕

Hereinafter, embodiments of the present invention will be described with reference to the drawings.

In the intake device of the present invention, the V-type reed valve 10 illustrated in FIG. 1 is used. In addition, this reed valve
Reference numeral 10 is arranged in an intake passage of a two-cycle engine (not shown).

The reed valve 10 has a mounting frame 11 and a valve seat block 12 having a V-shaped side surface, which are integrally molded of aluminum alloy.

The mounting frame 11 is integrally formed along the peripheral edge of the base end of the valve seat block 12, and the coil 15 is wound around the side portion 14 located above the window 13 provided above the valve frame.

The valve seat block 12 has an upper valve seat 16 and a lower valve seat 16 ', respectively, on the upper surface and the lower surface thereof.
Is composed.

As shown in FIG. 2, the upper valve seat 16 is formed with three vent holes 18a, 18b and 18c penetrating through the seat 16, and as shown in FIG. On the valve seat 16, upper leads 24a, 24b, and 24c for opening and closing the ventilation holes 18a to 18c are provided.
Each of the upper leads 24a, 24b, and 24c is formed of a material such as a steel plate having elasticity and magnetism, and the rear end portion of each is fixed to the valve seat 16.

On the other hand, a portion of the upper valve seat 16 located below the tips of the upper leads 24a, 24b, 24c is provided with a magnetic path for applying a magnetic attraction force to these leads 24a, 24b, 24c. Therefore, iron plates 19, 20, 21 and 22) are arranged in an array.

The iron plates 19 and 20 located at the one side edge and the other side edge of the valve seat 16 are extended along the one side edge and the other side edge of the mounting frame 11, and the extension portions thereof are The upper end is coupled to one end and the other end of the iron plate 23 arranged on the side portion 14 of the mounting frame 11.

The iron plates 19, 20, 21 and 22 are arranged so that their surfaces coincide with the surface of the valve seat 16.

When the coil 15 is excited, the iron plates 19 to 23 and the upper leads 24a to 24c form a closed magnetic circuit, and the magnetic attraction force generated at that time causes the tip of the lead 24a to move to the iron plate 1.
9,21 and lead 24b that lead to iron plate 21,22
That of 24c is adsorbed to the iron plates 20 and 22, respectively.

In this way, the coil 15 and the iron plates 19-23 are connected to the leads 24a-2
It functions as an electromagnet forcibly attracting 4c to the valve seat 16 side.

By the way, as shown in FIG. 3, the lower valve seat 1
6'also has ventilation holes 18a'-18 corresponding to the above ventilation holes 18a-18c.
c'and lower leads 24a 'to 24c' for opening and closing these vent holes 18a 'to 18c' are provided.

However, the lower valve seat 16 ′ has the above-mentioned iron plates 19 to 22.
Since the coil is not provided, magnetic attraction does not act on the leads 24a 'to 24c' even when the coil 15 is excited.

In FIG. 3, reference numerals 25 and 25 'indicate stoppers for restricting the operation amounts of the upper leads 24a to 24c and the lower leads 24a' to 24c ', respectively, which are omitted in FIG. Has been done.

The engine speed sensor 30 shown in FIG. 1 detects the speed of a two-cycle engine (not shown) to which this embodiment is applied, and outputs a signal corresponding to this speed to a speed range determination circuit 31. To do.

The rotation speed range determination circuit 31 has a comparison element for determining whether or not the engine rotation speed shows a preset low rotation speed range value. When it is determined that the engine speed is in the low speed range, an electromagnet drive command is output to the drive circuit 32, whereby the coil 15 is excited.

Now, assuming that the engine speed shows a value in a low speed range, the coil 15 is excited, and as a result, the upper leads 24a to 24c are magnetically attracted to the upper valve seat 16 side. Therefore, when a negative pressure is generated in the crankcase of the engine, as shown in FIG. 4, only the lower leads 24a'-24c 'are opened, and as a result, the vent holes 18a'-1
The air-fuel mixture is supplied into the crankcase via 8c '.

On the other hand, when the engine speed increases and shows a value in the high speed range, the coil 15 is demagnetized, so
The magnetic attractive force acting on 24a to 24c disappears.

As a result, as shown in FIG. 5, the leads 24a to 24c and the lower leads 24a 'to 24c' are opened together by the action of the negative pressure, whereby the vent holes 18a to 18c and 18a 'to 18c' are opened.
The air-fuel mixture is supplied into the crankcase (not shown) via both of the above.

Thus, in the intake system according to this embodiment, the intake amount when the engine is operating in the low speed range is
Compared to when operating in the high speed range, it decreases.

Therefore, if the air flow rate of the reed valve 10 is set so that the maximum output is obtained in the state shown in Fig. 5, an appropriate amount of air-fuel mixture is supplied to the engine even in the low rotation speed range, whereby the low rotation speed is obtained. The output in the range is improved.

As described above, since the magnetic attraction is not applied to the lower leads 24a'-24c ', these leads 24a'-2c
It is also possible to form 4c 'with a material such as FRP which is not a magnetic material.

[Effect of device]

According to the present invention, since the intake air amount during the operation in the low engine speed range is reduced as compared with the intake air amount during the operation in the high engine speed region, the engine speed range from the low engine speed range to the high engine speed range is increased. It is possible to improve the engine output.

In addition, since the coil, which is a component of the electromagnet, is provided in the mounting frame, in other words, since only the magnetic path for applying the magnetic attraction force to the upper lead is provided in the upper valve seat, the valve seat block is not provided. It is not necessary to have a special shape for disposing and wiring the coil. And
A coil having a large capacity can be used to form a magnet having a sufficient magnetic attraction force, and wiring of the coil can be facilitated and heat generation can be reduced.

Further, since only the upper lead is adsorbed, the flow height of the supply air during the operation in the low rotation speed range becomes low, and therefore the blow-by due to the inertia of the air-fuel mixture during the scavenging should be reduced as much as possible. You can

[Brief description of drawings]

FIG. 1 is a perspective view conceptually showing an embodiment of an air intake device according to the present invention, FIG. 2 is a perspective view showing an arrangement of ventilation holes and iron plates, and FIGS. 6 is a sectional view showing the operation of the embodiment, FIG. 6 is a sectional view showing an example of a two-cycle engine, and FIG. 7 is an enlarged sectional view showing the structure of the seed valve of FIG. 10 ... Reed valve, 11 ... Mounting frame, 12 ... Bubble seat block, 15 ... Coil, 16 ... Upper bubble seat,
16 '... Lower bubble sheet, 18a-18c, 18a'-18c' ...
… Ventilation holes, 19 ～ 23 …… Steel plate, 24a ～ 24c …… Upper lead,
24a 'to 24c' ... lower lead, 31 ... engine rotation sensor, 32 ... rotation speed range judgment circuit, 33 ... drive circuit.

Claims (1)

(57) [Scope of utility model registration request] 1. A valve seat block (12) having a V-shaped side surface, and an upper surface and a lower surface constituting an upper valve seat (16) and a lower valve seat (16 '), respectively, and a base of the valve seat block 12. A mounting frame (11) integrally formed along the peripheral edge, and upper leads (24a, 24c) for opening and closing the vent holes (18a, 18b, 18c) provided in the upper valve seat (16).
b, 24c) and the lower lead (2) for opening and closing the vent holes (18a ', 18b', 18c ') provided in the lower valve seat (16').
4a ′, 24b ′, 24c ′), and the upper leads (24a, 24b,
24c) is made of a magnetic material, and a magnetic path (19, 20, 21, 22) for applying a magnetic attraction force to the upper leads (24a, 24b, 24c) is provided on the upper valve seat (16). And a reed valve (10) formed by additionally attaching a coil (15) constituting an electromagnet together with the magnetic path (19, 20, 21, 22) to the mounting frame (11) and the engine speed. A rotation speed detection means (30) for detecting, and a magnet for energizing the coil (15) when the engine rotation speed detected by the rotation speed detection means (30) shows a preset low rotation speed range value. An intake device for a two-cycle engine, comprising: a control means (31, 32).