JPS5910357Y2 - Intake air amount control device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a device for controlling the amount of intake air by providing a rotary valve in an intake port upstream of an intake valve of an internal combustion engine.

One obstacle to improving the fuel efficiency of internal combustion engines is the problem of pumping loss due to the throttling action of a butterfly-type throttle valve installed in the intake passage.

Pumping loss is negative work based on the suction negative pressure that acts on the piston after the intake valve is opened, and the work loss becomes larger in a low load region where the suction negative pressure increases.

Therefore, when operating with the throttle valve fully open or in a diesel engine without a throttle valve, pumping loss is significantly reduced and fuel efficiency is improved.

In a normal spark ignition engine, the amount of intake air is controlled by a throttle valve, so this intake throttle loss cannot be eliminated.

For this reason, as shown in Utility Model Publication No. 50-20164, there are some systems that move a cam to variably operate the valve timing, but this system moves a cam that rotates at high speed and is subject to a large force. The mechanism was extremely complicated.

Therefore, instead of eliminating the butterfly-type throttle valve from the intake passage, the present invention provides a second rotano-type valve in the intake port, and controls the opening period of the second valve when the intake valve is opened, thereby increasing the amount of intake air. An object of the present invention is to provide an intake air amount control device which eliminates the intake throttling effect, reduces pumping loss, and improves fuel efficiency.

Hereinafter, embodiments of the present invention will be described based on the drawings.

In Fig. 1, 1 is a cylinder, 2 is a cylinder head,
3 is a combustion chamber, and communication between the combustion chamber 3 and the intake port 4 is opened and closed by an intake valve 6 that follows a cam 5 that rotates in synchronization with engine rotation, and this intake valve 6 is operated near top dead center during the engine intake stroke. The valve is opened from to near the bottom dead center, and remains closed otherwise.

Note that 7 is a rocker arm for the intake valve, 8 is a rocker arm for the exhaust valve, and 9 is a rocker arm for the exhaust valve.
9 is driven by a cam 5 disposed coaxially with the camshaft or an exhaust valve cam (not shown).

A rotary valve 10 is provided as a second intake valve immediately before the intake valve 6 so that the volume between the intake port 4 and the intake valve 6 is as small as possible. It rotates around an axis perpendicular to the axis, and opens and closes the intake port 4 through communication with the valve hole 11.

Therefore, when the rotary valve 10 is open, air (air mixture) is sucked into the combustion chamber 3 via the intake valve 6, but when the rotary valve 10 is closed, even though the intake valve 6 is open. No air is taken in, and therefore the amount of intake air is controlled based on the overlap between the opening period of the rotary valve 10 and the opening timing of the intake valve 6.

By the way, the rotor shaft 13 of the rotary valve 10 is
As is clear from the figure, the valve hole 11 is freely slidable in the axial direction with respect to the rotation axis, and the shape of the valve hole 11 is such that the opening area changes with respect to the movement in the axial direction. is formed on the tapered surface 12.

The shape of the intake ports 1 and 4 on the valve peripheral surface is a rectangle 4a, and therefore the opening period of the rotary valve 10 decreases as the rotor shaft 13 moves to the right in FIG.

A piston 16 of a hydraulic cylinder 15 is in contact with the end of the rotor shaft 13 via a thrust bearing 14, and as the oil pressure in the hydraulic chamber 18 increases against the return spring 17, the piston 16 moves to the right. .

The oil pressure supplied to the oil pressure chamber 18 is controlled by a solenoid valve 21 operated by a signal from a control circuit 20, and the oil pressure increases or decreases depending on the engine rotation speed signal and the accelerator opening.

On the other hand, rotation from the engine crankshaft is transmitted via a gear 24 to a gear 23 fixed to the other end of the rotor shaft 13 .

Note that the effective meshing length of the gear 24 is determined in accordance with the amount of displacement of the rotor shaft 13 in the axial direction.

Next, it will be explained in more detail, including its effect.

The opening/closing timing of the intake valve 6 is appropriately set in consideration of the air-fuel mixture filling efficiency during high-speed engine operation.On the other hand, the rotary valve 10 opens twice per revolution, so in a 4-cycle engine The rotary valves 10 and 10 are set to rotate so as to rotate with each revolution of the crankshaft, and to open the rotary valve 10 while the intake valve 6 is opening.

In the operating range where the accelerator opening is small, the hydraulic pressure supplied to the hydraulic cylinder 15 is large, and therefore the rotor shaft 13 is
Moving to the right in the figure, the open period of the rotary valve 10 becomes near the minimum.

In such a case, even if the intake valve 6 and the rotary valve 10 open at the same time, the rotary valve 10 will close before the intake valve 6 (or delay the opening of the rotary valve 10), so that the intake air will be reduced. quantity becomes smaller.

The longer the rotary valve 10 is open, the more the intake air amount increases.
The position becomes as shown in Figure 2, and the opening period of the rotano valve 10 and the opening period of the intake valve 6 match (or the opening period of the rotary valve 10 becomes larger), and the maximum intake air amount is reached. is obtained.

By controlling the amount of intake air in this way, the negative intake pressure that acts on the piston when the rotary valve 10 and intake valve 6 overlap is different from when the intake passage is throttled by a throttle valve.
Since almost no throttling action occurs when the rotary valve 10 is opened, the pressure becomes approximately atmospheric.

Further, after the rotary valve 10 is closed, the downstream intake port 1-4 and the combustion chamber 3 become a sealed space, and the suction work caused by the subsequent descent of the piston can be recovered to some extent as the piston's lifting action during the compression stroke.

Therefore, the negative work that acts on the piston during the intake stroke is significantly reduced compared to a conventional system in which the amount of intake air is controlled using a throttle valve, and fuel efficiency is improved by reducing so-called pumping loss.

Note that in order to enhance the effect of reducing pumping loss, the space volume from the rotary valve 10 to the intake valve seat may be reduced as much as possible.

Furthermore, if the rotary valve 10 is not opened at all during engine deceleration, in other words, if the rotor shaft 13 is moved so far that the valve hole 11 is removed from the intake port 4, fuel can be cut during deceleration, thereby improving fuel efficiency. Further improvements will be made.

As described above, according to the present invention, the rotary valve is provided upstream of the intake valve to control the amount of intake air without causing an intake throttling effect, thereby improving fuel efficiency by reducing pumping loss.

The amount of intake air can be increased or decreased with a simple structure of moving the rotary valve in the rotor axial direction depending on the operating condition, and there is an advantage that it can be put into practical use at low cost.

[Brief explanation of the drawing]

FIG. 1 is a sectional view showing an embodiment of the present invention, FIG. 2 is a front view of a rotary valve, and FIG. 3 is a diagram showing the operating characteristics of the present invention. 2...Cylinder head, 3...Combustion chamber, 4...Intake port, 5...Cam, 6
... Intake valve, 10 ... Rotary valve, 11 ... Valve hole, 13 ... Rotor shaft, 15 ... Hydraulic cylinder, 24・・・・・・
control circuit.

Claims (1)

[Scope of utility model registration request] A rotary valve for opening and closing the port is provided at the intake port upstream of the intake valve, the intake valve and the rotary valve are driven in synchronization with engine rotation, and a drive means is provided for displacing the rotary valve in the axial direction. An intake air amount control device configured to change a valve opening period in accordance with the amount of displacement, and increase or decrease the overlap of a rotary valve with respect to an intake valve in accordance with operating conditions.