JPS58117317A - Suction device for four-cycle engine - Google Patents

Abstract

PURPOSE:To flow a suction from a by-suction path forcibly into a cylinder by closing an opening and closing valve at the downstream of a throttle valve in a low-load operation zone containing idling. CONSTITUTION:When the quantity of an accelerator grip 13 turned and operated is little, a wire 26 is not pulled bacause the quantity of a connecting member 25 displaced is also little, and the opening and closing valve 17 is closed. The suction does not pass through a suction path 3, flows into the cylinder (a) from the by-suction path 18, and is changed into a spiral vortex. When the quantity of the accelerator grip 13 turned and operated exceeds a predetermined value, the wire 26 is pulled, and the opening and closing valve 17 is opened. In intermediate-load and high-load operation zones, the opening and closing valve 17 is opened completely, and the suction flows into the cylinder 2 through the suction path 3 and a suction valve 5.

Description

[Detailed description of the invention] The present invention relates to an intake system for a four-cycle engine.

In a four-cycle engine VC, the pA of the amount of intake air taken into the cylinder is normally adjusted by a throttle valve of a carburetor provided in the intake system.

However, the throttle valve is said to be fully closed at about 11 degrees or an extremely low torque of 1 degree in a low load operating range including engine idling.

For this reason, the resistance when the intake air passes through the throttle valve becomes large, increasing the resistance to the intake air into the cylinder, and the amount of intake air drawn into the cylinder tends to be insufficient. The intake valve, which opens and closes the passage, closes later than usual.

However, in this case, the loss of the amount of intake air into the cylinder, that is, the pumping loss increases, and the fuel consumption rate of the engine decreases.

The present invention was developed in view of the epic situation, and its purpose is to improve the fuel consumption rate by slightly changing the pumping loss in the low engine operating range, including the idle link of the engine. There is a thing called VC.

One embodiment of the present invention will be explained with reference to drawings regarding an intake system for a four-stroke engine for a motorcycle.
4-stroke engine, (a) UN engine (A) consists of four cylinders, below (b) is the cylinder head, (c) is the U cylinder head cover.

A liner (1) is cast into the inner periphery of the cylinder (a), and a piston (d) is fitted into the liner (1) in a freely V-fitted manner.

(2) is a combustion chamber formed between the lower surface of the cylinder head (b) and the upper end of the piston (a) located at top dead center, and this combustion chamber (2) has an intake passage (3) and an exhaust passage. aisle(
4) and are open facing each other.

(5) is an intake valve that opens and closes the intake passage (3); (6)
are exhaust valves that open and close the exhaust passage (4), and each of these intake and exhaust valves (51<6)σ has a rocker arm (7) at its upper end.
) (8) k connected to one camshaft (9),
As the camshaft (9) rotates, the amount of kA is reduced. (9a) is a cam for driving the intake valve (5) provided in the cam [11H9], and (9b) Fi is a cam for driving the exhaust valve (6).

(It is a carburetor installed on the upstream side of the intake passage (3) on IQσ, and it is a carburetor installed on the upstream side of the intake passage (3)
) is connected to rubber whale joint tll)k.

(2) is a throttle valve provided in the intake passage (3) of the carburetor a1, and by adjusting the opening of this throttle valve α4, the amount of intake air sucked into the cylinder (a) is adjusted. It looks like this.

The throttle valve 02 is connected to an accelerator grip 03 provided on a steering handle (not shown), and is opened and closed by rotating the grip.

A is an operating rod connected to the support @II (12a) of the throttle valve (6), and is connected to the operating member C10 via a wire Q5.

The operating member 0Q is connected to the accelerator grip via a wire (c) so as to rotate together with it, and the wire 4 from the operating lever MU is connected to the wire (c).
6) is provided with a locking part (16a) for winding it up.

The locking part (16a) in item IJ is such that the vicinity of the connection part of the wire α protrudes in the same direction in the rotational direction of the actuating force αQ, and the part away from the connection part is rearward in the rotational direction of the actuation member Ofj. It's retreating.

Therefore, the amount of rotational operation of the accelerator grip α1 is small f
! In the case where the wire .alpha.$ is wound up, there is less wire .alpha., so the throttle valve .alpha. and,
When the amount of rotational operation of the accelerator grip α3 exceeds a predetermined value, the wire (15) is pulled greatly, so the opening degree of the throttle valve (2) σ accelerator grip (130) increases rapidly in proportion to the rotational operation. .

FIG. 3 shows a graph of changes in the opening degree of the throttle valve @ with respect to the amount of rotational operation of the accelerator grip α3.

The part indicated by the dotted line in the figure represents the change in the opening degree of the conventional throttle valve, and in comparison with this, the throttle valve (c) of this example initially had a larger opening degree than the conventional one, and from there the accelerator grip The opening degree gradually increases until the rotational operation amount (to) reaches a predetermined value or more, and thereafter the opening degree increases as in the conventional case.

(lη is the intake air amount lll1!F(3) between the mi1 distribution throttle valve 04 and the intake valve (5), preferably enshiff (
A) IUl: Intake passage (3) VC5 is a general cut-off on-off valve.

This on-off valve 07) is fully closed in the low-load operating range of the engine (A) and closes the intake passage (3) on the downstream side of the throttle valve (2), and (c) is the support shaft (17a) of the on-off valve αη.
It is an operating rod connected to the operating member (16) by two wires (C) @ connected via a cylindrical connecting member (C).

The tip of the wire on the operating rod (c) side is inserted into the connecting member (c), and a gap is provided between it and the bottom wall (25a) of the connecting part (to) that holds it. ing.

-10, One end of the wire @ of the operating member 00 and 1 is locked to the operating member αQ, and the bent end is connected to the connecting member via a spring (C).

(16b) is the throttle valve (
This locking portion is provided adjacent to the locking portion (16a) of the wire aQ connected to the wire aQ (2), and is configured to fully lock the wire on the operating member (g) side.

As the actuating member rotates in conjunction with the rotating operation of the accelerator grip α4, the wires secured to the parts (1 to 1) are pulled, causing the spring (c) to actuate the valve. 6- Although the offshore member 9 is displaced upward in Figure 1 VC, if the amount of operation of the open piaxel grip αJ is small, the displacement of the connecting part is also small, so The wire (C) of the operating rod (C) 1u11 is not locked to the bottom wall (25a) of the member, and the wire (C) is not pulled.

Therefore, the on-off valve 07) maintains the fully closed state.

Then, when the rotation operation lid of the accelerator grip 03 reaches a predetermined level or more, the wire (c) on the operating rod (c) side is connected to the connecting member (c).
C) is engaged and pulled, and the operating rod (C) rotates downward in Figure iA1 to open [if+valve αη is opened.

In addition, after the on-off valve 0''i) is fully opened, the pi (c) is knitted as the accelerator grip αJ is rotated, and only the wire (b) on the operating member M side is pulled 'D). It has become.

FIG. 3 shows changes in the opening lf of the opening/closing valve α force of the accelerator grip αJ with respect to the rotary operation lid in relation to a single change in the throttle valve α.

As is clear from Figure 111, the opening/closing -3f IJ71 was initially fully closed, and when the number of times the accelerator grip reached a predetermined level or more, the opening degree suddenly increased and became fully open. The fully open state is #1Ilf+.

0 is the intake passage (3) on the upstream and downstream sides of the on-off valve αη.
) is an auxiliary intake passage that communicates with the valve q7) by bypassing the valve q7). This sub-intake passage 0 barrel has a smaller cross-sectional area than the intake passage (3), is formed adjacent to the passage (3) on the wall that constitutes the intake passage (3), and has an opening on the downstream side ( 18
a) is the combustion chamber (2) from the opening (3a) of the intake passage (3).
) It is facing away from the center of the navel.

Therefore, the intake air from the intake control passage frame a is transferred to the cylinder (a
) and forms a vortex, allowing the combustion of the intake air to occur at high speed and stably.

(19H This is a sub-intake valve that opens and closes the sub-intake passage α, and is provided in a vertical hole (7) intersecting with the sub-intake passage 0 so as to be slidable up and down with a guide qη.

This auxiliary intake valve UL [the above-mentioned intake and exhaust valve (51(6) is driven by the camshaft (9) and the rocker arm) is connected to the valve so that it can be closed earlier than the intake valve (5). ing.

Therefore, in order to satisfy all the operating conditions of the sub-intake valve α-, the cam (9C) for driving the valve (1!!) is parallel to the cam (9a) for driving the intake valve (5) on the camshaft (91). The top portion of the cam shaft (9) is positioned forward of the cam (9a) for the intake valve (5) in the rotational direction.

Note that the arrow in the figure is a plug that closes the vertical hole (E).

, such intake system & is the throttle valve of the carburetor αQ in the low load operating range including the idle link of the engine (A), 12
Since it is opened more widely than before, the intake air passes through the throttle valve 02 and flows into the intake passage (3) on the downstream side of the throttle valve 02 without encountering large resistance.

Therefore, since the throttle valve C1 is closed by the σ angle closing valve Uη of the intake passage (3) at tN and 1ltll, the intake air flows from the intake passage (3) to the auxiliary intake passage 4, and from there the auxiliary intake passage An appropriate amount is sucked into the cylinder (al) through valve 01.

10,000, in the medium load and still negative operating range of the engine (A), the f''i on/off valve (17) is fully opened, and the cylinder (a) is Inhaled air is drawn in.

Since the present invention is configured as described above, the intake passage is closed by the on-off valve in the low-load operating range including engine idle, and the intake air flows from the intake passage downstream of the throttle valve of the carburetor to the auxiliary intake passage and the auxiliary intake passage. Since the intake valve is sucked into the cylinder through the valve, and the sub-intake valve is closed earlier than the intake valve, the opening of the throttle valve of the carburetor can be fully increased in the low-load operating range including the idle link of the engine. This makes it possible to reduce the intake resistance of intake air, allow an appropriate amount of intake air to be drawn into the cylinder, reduce the loss of intake air amount, that is, the pumping loss, and improve the fuel consumption rate of the engine.

Also, when the engine is in an operating range other than the above-mentioned low-load operating range, the on-off valve is fully open and the intake passage is opened.
Intake air is drawn into the cylinder through the intake passage and intake valve as before, and does not interfere with engine operation.

Therefore, the intended purpose can be achieved.

[Brief explanation of the drawing]

10- Fig. 1 is a longitudinal sectional view showing the intake device of the present invention, Fig. 2 is a sectional view taken along line (Il)-(II) in Fig. 1, and Fig. 3 is a longitudinal sectional view showing the intake device of the present invention. It is a graph which shows the opening degree change of an on-off valve. In the figure (A)... 4-cycle engine (a)... Cylinder (2)... Combustion chamber (3)... Intake passage (5
)...Intake valve (1[J...Carburizer 02...Throttle valve q″θ...Opening/closing valve 04...Sub-intake passage (11...Sub-intake valve

Claims (1)

[Claims] (I) In a 4-cycle engine, the intake mm between the throttle valve and the intake valve of the carburetor provided on the intake line
In addition, an on-off valve is installed that is fully closed in the low-load operating range, including engine idle link, and is fully open in other operating ranges, and intake ventilation is installed on the upstream and downstream sides of this on-off valve. An intake system for a four-cycle engine, which is provided with a sub-intake passage which is communicated by bypassing τ, and which is provided with a sub-intake valve that closes at one time earlier than the above-mentioned intake valve. (2) An intake system for a four-cycle engine according to claim 1, wherein the auxiliary intake passage faces the combustion chamber in a manner that is deflected from the center of the combustion chamber.