JPS6146646B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an internal combustion engine in which a second intake valve is provided upstream of an intake valve to control the amount of intake air and reduce engine pumping loss.

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

Pumping loss is negative work based on the negative suction pressure that acts on the piston after the intake valve opens.
The work loss becomes larger in the lower load range 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 normal spark ignition engines, the amount of intake air is controlled by a throttle valve, so it is impossible to eliminate intake throttle loss.

Therefore, the present invention eliminates the butterfly type throttle valve from the intake passage, provides a second valve that can open and close the passage at the engine intake port, and controls the opening period of the second valve when the intake valve is opened. The purpose of the present invention is to provide a spark ignition internal combustion engine which controls the amount of intake air and eliminates the intake throttling effect, resulting in less pumping loss and excellent fuel efficiency.

Embodiments of the present invention will be described below based on the drawings.

In FIG. 1, 1 is a cylinder, 2 is a cylinder head, and 3 is a piston, and a combustion chamber 4 is defined by these.

Communication between the combustion chamber 4 and the intake port 5 is provided by an intake valve 6.
The intake valve 6 is opened and closed in synchronization with engine rotation via the
is driven by the valve mechanism 7 to open from near top dead center to near bottom dead center during the engine suction stroke.

Reference numeral 8 indicates a rocker arm for the intake valve, and reference numeral 9 indicates a rocker arm for the exhaust valve, which are driven by an intake cam 11 and an exhaust cam 12 mounted on a camshaft 10, respectively, to open and close the intake valve 6 and the exhaust valve 13.

By the way, a rotary valve 15 is provided in the intake port 5 as a second intake valve just before the intake valve 6, and the rotary valve 15 rotates about an axis perpendicular to the intake port axis,
6 opens and closes the intake port 5.

Therefore, when the rotary valve 15 is open, air (air mixture) is sucked into the cylinder 1 via the intake valve 6, but when the rotary valve 15 is closed, even if the intake valve 6 is opened. No air is taken in, so the intake air amount is controlled based on the overlap between the opening timing of the rotary valve 15 and the opening timing of the intake valve 6.

Here, the rotary valve 15 is designed to rotate in conjunction with the camshaft 10, and as shown in FIG.
8 meshes with the gear 19 of the camshaft 10, and as a result, it is driven in synchronization with the rotation of the engine crankshaft.

As a means for variably controlling the opening/closing phase of the rotary valve 15 according to the engine operating state (accelerator opening degree), a differential gear consisting of a combination of bevel gears is provided between the drive shaft 17 and the rotary valve 15. A gear mechanism 20 is interposed.

The gear 21a is coaxially directly connected to the drive shaft 17, and the gear 21b opposite thereto is directly connected coaxially to the rotary valve 15, while the gears 22a and 22b are rotatably supported by the control shaft 23 and connected to the gear 21a. , 21b.

Therefore, when the control shaft 23 is rotated in the rotational direction (circumferential direction) of the gears 21a, 21b as shown in FIG.
The meshing phase of gears a and 22b changes, and the gear 21a
Since there is a phase difference in the rotational transmission angle between and 21b,
Utilizing this, the opening period of the rotary valve 15 can be advanced or delayed relative to the rotation of the camshaft 10, that is, the opening and closing of the intake valve 6.

The rotation angle of the control shaft 23 is controlled such that it increases or decreases depending on the amount of depression of the accelerator pedal, for example. In the figure, 25 is a spark plug, and 26 is an exhaust manifold.

The structure is as described above, and the operation thereof will be explained next with reference to FIG.

The opening/closing timing of the intake valve 6 is appropriately set in consideration of the air-fuel mixture filling efficiency in the cylinder during high-speed engine operation.On the other hand, if the opening period of the rotary valve 15 is controlled as shown in the figure, both Air-fuel mixture is inhaled only while both valves are open (shaded area).

Therefore, if the amount of overlap is reduced, the amount of intake air (air mixture filling amount in the cylinder) will be decreased, and if the amount of overlap is increased, the amount of intake air will be increased, and the rotary valve 15 will be closed during the period when the intake valve 6 is open. The maximum flow rate occurs when the valve is fully opened.

Such timing control of the opening period of the rotary valve 15 is performed by displacing the rotation transmission phase angle of the differential gear mechanism 20 via the control shaft 23. The valve is moved relatively early and delayed in high load areas.

On the other hand, when the intake air amount is controlled in this way, the suction negative pressure that acts on the piston 3 when the rotary valve and the intake valve overlap is hardly throttled by the throttle valve, and the rotary valve 15 is synchronized with the engine rotation. Since the rotary valve 15 rotates and has a fully open time, the pressure is close to atmospheric pressure, and after the rotary valve 15 is closed, the downstream intake port 5 and the combustion chamber 4 become a sealed space, and the suction loss due to the subsequent descent of the piston 3 is Since the pumping loss can be recovered to some extent as a pulling action of the piston 3 during the compression stroke, the pumping loss is significantly reduced compared to a control method using a normal throttle valve.

Note that in order to enhance the pumping loss reduction effect, the intake port space from the rotary valve 16 to the valve seat of the intake valve 6 may be reduced as much as possible.

When the engine decelerates, by reducing the valve overlap between the rotary valve 15 and the intake valve 6 to zero, it is possible to realize a so-called fuel cut system during deceleration, in which no air-fuel mixture is supplied into the cylinder, which further improves fuel efficiency. Improvements will be made.

As described above, the present invention provides the intake port with an intake valve that opens and closes in synchronization with engine rotation, and provides a cylindrical rotary valve that is close to the upstream side of the intake valve and perpendicular to the intake port. The rotary valve is rotatably driven in synchronization with the engine rotation, and is provided with a control means for relatively changing the opening/closing phase of the rotary valve, and the valve opening overlap amount of the rotary valve with respect to the opening/closing period of the intake valve increases as the engine load increases. Since the control means is linked with the load control means of the control means, the amount of intake air can be controlled according to the amount of valve opening overlap of the rotary valve, and by reducing the amount of valve opening overlap in the partial load region of the engine, pumping loss can be reduced. It is possible to improve fuel efficiency by reducing fuel consumption. Further, since the rotary valve is cylindrical and is provided close to the intake valve, the downstream passage space when the rotary valve is closed is reduced, and the effect of reducing pumping loss is large.

[Brief explanation of the drawing]

FIG. 1 is a sectional view of the present invention, FIG. 2 is a plan view of the valve train, FIG. 3 is a front view of the differential gear mechanism, and FIG. 4 is an explanatory diagram showing the valve opening and closing characteristics of the present invention. DESCRIPTION OF SYMBOLS 1... Cylinder, 3... Piston, 4... Combustion chamber, 5... Intake port, 6... Intake valve, 7... Valve mechanism, 10... Camshaft, 11... Intake cam, 1
2...Exhaust cam, 15...Rotary valve, 16
... Valve hole, 17 ... Drive shaft, 20 ... Differential gear mechanism, 21a, 21b, 22a, 22b ... Bevel gear, 23 ... Control shaft.

Claims (1)

[Claims] 1. An intake valve that opens and closes in synchronization with engine rotation is provided at the intake port, and a cylindrical rotary valve is provided close to the upstream side of this intake valve and perpendicular to the intake port.
This rotary valve is rotationally driven in synchronization with engine rotation, and a control means is provided to relatively change the opening/closing phase of this rotary valve, and the amount of overlap in opening of the rotary valve with respect to the opening period of the intake valve increases the engine load. 1. A spark ignition internal combustion engine, characterized in that said control means is linked with engine load control means so that the load increases as the load increases.