JPH0423094B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an improvement of a Siamese intake two-valve internal combustion engine.

Conventionally, in a two-valve intake internal combustion engine, combustion is improved by stopping the inflow of fresh air from one intake valve during low load to form a swirl around the cylinder axis within the combustion chamber. However, in the case of the so-called four-valve type, in which two exhaust valves are provided opposite the intake valve, cooling of the exhaust valve on one side is insufficient, which tends to cause knocking, making it impossible to maintain a high compression ratio. If the ignition plug is placed at the center of the combustion chamber, which coincides with the cylinder axis, an intake air stagnation area is formed near the cylinder axis, slowing down the intake air flow rate near the ignition plug, and preventing scavenging around the ignition plug. When the amount becomes sufficient, not only the ignitability deteriorates but also the combustion efficiency decreases. Furthermore, in a gasoline injection engine, if one injector is used, fuel cannot be injected into the intake valve where the inflow of fresh air is stopped, and only air flows from this intake valve at high output. This causes insufficient mixing of the air-fuel mixture within the combustion chamber, resulting in a decrease in output. If two injectors are used as a countermeasure to this problem, the air-fuel mixture can be made uniform, but there are various problems such as the need to control the injector on the side of the inactive intake valve, which significantly increases costs.

The present invention was made in view of the above-mentioned problems, and aims to prevent intake air from stagnation near the ignition plug by directing a high-velocity intake air flow toward the ignition plug without causing swirl around the cylinder axis. It is an object of the present invention to provide an intake two-valve internal combustion engine that greatly contributes to improving ignition performance and increasing combustion efficiency.

In order to achieve the above object, the present invention provides a surge tank on the upstream side of an intake port, divides a portion of the intake port near the combustion chamber into two intake subports by a vertical wall, and separates each of the intake subports into an intake port. An intake valve that communicates with the combustion chamber through a valve and has an ignition plug located at the center of the top of the combustion chamber that coincides with the axis of the cylinder, and an exhaust valve that is located between the ignition plug and the opposite side of the intake valve. In the two-valve internal combustion engine, the vertical wall is set on a center line of the intake port intersecting the axis of the cylinder, and the two intake sub-ports are arranged at substantially symmetrical positions with respect to the vertical wall, and The surge tank and the intake port are connected by two intake passages having downstream outlets arranged above and below a plane perpendicular to the vertical wall, and one of the two intake passages is longer than the other. The intake sub-port is formed into a length, and the relatively short intake passage is completely closed at the confluence of the two intake passages on the intake port side or in the relatively short intake passage when the engine is under low load or rotates at low speed. The engine is characterized in that a control valve is disposed on the upper wall or the lower wall to divert the intake air and to fully open the relatively short intake passage when the engine is under high load or rotates at high speed. and,
With this configuration, by operating the control valve when the engine is under low load or rotating at low speed, an equal two-axis vertical swirl is generated in the left and right directions within the combustion chamber, and the streamline vector of the intake air is aligned with the combustion chamber. The scavenging air around the ignition plug is sufficient to direct the air toward the ignition plug located at the center of the top of the ignition plug.

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

FIG. 1 is a sectional view showing a first embodiment of the present invention, FIG. 2 is a sectional view taken along the - line in FIG. 1, and FIG. 3 is a schematic diagram of a four-cylinder engine also showing the first embodiment. 4 is a sectional view showing the second embodiment, FIG. 5 is a sectional view taken along the line - in FIG. 4, and FIGS. 6 to 10 are explanatory views showing other embodiments. be.

In Figures 1 to 3, 1 is a cylinder head, 2 is two exhaust valves per cylinder, and 3 is two intake valves located symmetrically with the exhaust valve 2 with the axis of the cylinder 20 as the center. , 21 is the cylinder 20
The ignition plug is located at the center of the top of the combustion chamber, which coincides with the axis of the combustion chamber, and 4 is the intake port. Intake port 4
is a vertical wall 22 provided on the center line of the intake port, the part of which is closer to the combustion chamber intersects the axis of the cylinder.
The intake subport 4a, 4b is divided into two intake subports 4a, 4b, and each intake subport 4a, 4b communicates with the combustion chamber via the intake valve 3. 5 is an injector that injects fuel toward the intake valve 3; 51 is a delivery pipe that supplies fuel to the injector 5 of each cylinder; and 6 is a notch that allows fresh air to flow in only from the upper part of the intake port 4 when the intake port 4 is fully closed. 7 is a branch that is partitioned into two upper and lower stages when the control valve 6 is fully open;
71 divides the branch 7 and surge tank 9 upstream from the control valve 6 into two stages, the first branch 8 having a longer distance and the second branch 1 having a shorter distance.
It is a full board that forms 0 and 0. In FIG. 1, l ₁ indicates the length of the first branch 8, and l ₂ indicates the length of the second branch 10. Further, 72 is a curved surface along which the end of the control valve 6 opposite to the side having the notch extends up to a certain angle, and a plane that partially contacts the back surface of the control valve 6 when the control valve 6 is fully closed. It is a wall surface made up of Further, in FIG. 3, 11 is a start injector that supplies fuel to the second branch 10 during a cold start, 61 is a rotating shaft that connects the control valves 6 of each cylinder, and 62 is a rotating shaft 6.
A lever 63 attached to the end of the engine 1 is an actuator that drives the lever 62, and controls the opening and closing operations of the control valve 6 according to the load or rotational speed of the engine. 12 is a throttle valve linked to an accelerator pedal 13.

The configuration of the first embodiment is as described above,
Next, the action will be explained.

At idle, at low load, at low speed, at low rotation speed, etc., the actuator 63 is actuated by a signal representing the engine condition, and the control valve 6 is rotated in the closing direction to allow the flow from the surge tank 9 to pass through the first branch 8. The fresh air flows through the notch in the upper part of the control valve 6 to the upper wall of the intake port 4, flows directly to the upper wall of the intake subports 4a and 4b, and flows into the combustion chamber from each intake valve 3. , after heading towards exhaust valve 2,
It flows in a spiral in the vertical direction, forming a so-called biaxial vertical swirl. At this time, the exhaust valve 2 is sufficiently cooled by fresh air, and the spark plug is sufficiently scavenged, so that the ignition performance and knock resistance can be improved, eliminating the problems in the prior art. Also,
Due to the action of the control valve 6 and the wall surface 72, fresh air does not flow into the second branch 10, so the positive pressure wave reflected from the surge tank 9 flows through the long first branch 8 and effectively controls the piston movement in the cylinder. By matching, the output (torque) can be improved due to the so-called intake inertia effect.

During high load or high speed rotation, the control valve 6 is fully open and fresh air flows into the intake port 4 from the short second branch 10, so the intake inertia effect is matched for high speed rotation and low speed rotation. The output will improve as time goes on. In FIG. 1, the two-dot chain line indicates a state in which the control valve 6 moves from a fully closed state to an open state.

FIG. 4 shows a second embodiment of the present invention, and FIG. 5 is a sectional view taken along the - line in FIG. 4. The difference between this embodiment and the first embodiment is that in the first embodiment, a butterfly valve type control valve 6 having a notch at the top is disposed upstream of the injector 5; A control body 14 is formed in the intake port 4 on the downstream side of the injector 5, and a rotary valve 15 having an elongated hole-shaped opening 151 in the center is disposed within the control body 14 as shown in FIG. It's what I did. Therefore, in FIG. 4, the same components as in the first embodiment are given the same reference numerals, and their explanation will be omitted.

In FIG. 4, the two-dot chain line indicates when the rotary valve 15 is fully closed, and at this time, the intake air that has passed through the first branch 8 passes through the diagonally inclined opening 151. , the air flows unevenly toward the lower wall of the intake port 4 and flows into the combustion chamber. Further, although the rotary valve 15 shown by a solid line in the figure is fully open, the operation and effect of the second embodiment are the same as those of the first embodiment.

6A and 6B show a third embodiment, in which the control valve 101 is provided on the second branch side.

FIGS. 7A and 7B show a fourth embodiment, in which the control valve 102 is retractable.

As described above, according to the two-valve intake internal combustion engine according to the present invention, by operating the control valve when the engine is under low load or rotating at low speed, vertical swirls on two axes equally on the left and right sides are generated in the combustion chamber. However, the scavenging air around the ignition plug provided at the center of the top of the combustion chamber becomes sufficient, which not only improves ignition performance but also improves combustion efficiency. Furthermore, when the present invention is applied to a four-valve internal combustion engine having two exhaust valves, the generation of the vertical swirl sufficiently cools the exhaust valves, thereby preventing a decrease in knocking resistance. Furthermore, when the engine is under low load or running at low speeds, the intake air flows selectively through the relatively long intake subpassage, so the intake inertia effect is matched for low speed rotation, while at high speeds the short intake subpassage flows through the relatively long intake subpassage. Since the engine is also opened, the intake inertia effect is matched to high-speed rotation, and output can be improved at both low-speed and high-speed rotation. Moreover, since one control valve has both the function of generating a vertical swirl and the function of maximizing intake inertia, the structure is simple.

Furthermore, if the present invention is applied to a gasoline injection engine as shown in the first and second embodiments, by simply arranging one injector at the gathering part of the intake sub-port, fuel can be distributed evenly from each intake valve to the combustion chamber. This has the additional effect of preventing a decrease in output due to insufficient mixing of the air-fuel mixture.

Further, the present invention can achieve the same effect even if a carburetor is used for each cylinder instead of an injector as a fuel supply device.

Further, according to the present invention, when combined with a supercharger, the supercharging pressure can be used as the control pressure of the actuator to compensate for the decrease in torque until supercharging is fully activated by the intake inertia effect. Further, by sharing the first and second branches, the supercharger can be operated from a low rotation speed.

Furthermore, when the present invention is combined with knocking prevention by water jetting, water can be jetted from the same position as in the second embodiment to promote atomization by drifting.

Furthermore, when the present invention is combined with a method of supplying fuel into a surge tank, vaporization is promoted by flowing the branch shape at high speed through pulsation.

Furthermore, when the present invention is combined with a diesel engine, diesel knock can be prevented and smoke can be reduced.

Note that when a helical port is used for one or both of the intake ports in the embodiment, it is preferable to create a biased flow along the upper wall surface of the intake port.

[Brief explanation of drawings]

1 is a sectional view of a first embodiment of the present invention, FIG. 2 is a sectional view taken along the - line in FIG. 1, FIG. 3 is a schematic plan view of a four-cylinder engine in the first embodiment, and FIG. The figure is a sectional view of the second embodiment, and FIG. 5 is a sectional view of the fourth embodiment.
A cross-sectional view along the - line in the figure, Figure 6 A and B are the 3rd
Explanatory diagrams of the embodiment, FIGS. 7A and 7B are explanatory diagrams of the fourth embodiment. 3... Intake valve, 4... Intake port, 6, 15,
101, 102, 103, 104, 105, 10
6...Control valve, 7...Branch, 8...First branch, 9...Surge tank, 10...Second branch, 71...Battery plate.

Claims (1)

[Claims] 1 Install a surge tank upstream of the intake port,
A portion of the intake port near the combustion chamber is divided into two intake subports by a vertical wall, each of the intake subports is communicated with the combustion chamber via an intake valve, and a portion of the top of the combustion chamber that is aligned with the axis of the cylinder is connected to the combustion chamber. In an intake two-valve internal combustion engine, in which an ignition plug is arranged at a central position, and an exhaust valve is arranged between the ignition plug and the intake valve on the opposite side, the intake valve is arranged such that the vertical wall intersects with the axis of the cylinder. The surge tank and the intake port are set on the center line of the port, and the two intake sub-ports are arranged at substantially symmetrical positions with respect to the vertical wall, and the surge tank and the intake port are placed above and below a plane perpendicular to the vertical wall. The two intake passages are connected by two intake passages each having a downstream outlet, and one of the two intake passages is formed longer than the other.
When the engine is under low load or rotates at low speed, the relatively short intake passages are completely closed and air is drawn into the upper or lower wall of the intake subport. 1. A two-valve intake internal combustion engine, characterized in that a control valve is disposed to bias the flow of air and fully open the relatively short intake passage when the engine is under high load or at high speed.