JPH0350326A - Internal combustion engine - Google Patents

Abstract

PURPOSE:To improve the combustion efficiency by opening and closing an air intake passage communicating with air intake valves except a central air intake valve in low and middle speed regions in accordance with load in an engine provided with the air intake valve facing a center of a combustion chamber and a plurality of air intake valves facing one side of the combustion chamber. CONSTITUTION:In a four cycle engine 1 provided with an air intake valve 3-4 facing a substantially central portion of a combustion chamber 40, a plurality of air intake valves 3-1 to 3-3 arranged at one side of the combustion chamber 40 so as to surround the air intake valve 3-4 and two exhaust valves 4-1 and 4-2 in a cylinder head 2, an air intake passage 16 commonly communicating with the air intake valves 3-1 to 3-2 and respective air intake passages 17, 18 communicating with the respective air intake valves 3-3, 3-4 are formed in the cylinder head 2. These air intake passages 16 to 18 are controlled by a valve mechanism 23 including a motor 27 so as to open and close the air intake passages 17, 16 communicating with the air intake valves 3-1 to 3-3 in the low and middle speed regions of the engine by a slide valve 24 in accordance with load.

Description

Detailed Description of the Invention (Field of Industrial Application) The present invention comprises an intake valve facing approximately the center of a combustion chamber, and a plurality of intake valves facing one side of the combustion chamber, and an intake valve connected to each intake valve. The present invention relates to an internal combustion engine in which passages are opened and closed according to rotational speed and load.

(Prior Art) In an internal combustion engine, the higher the rotation speed, the larger the required gas flow rate, so the opening areas of the intake and exhaust boats must be made larger. In particular, since the flow velocity of intake air is lower than that of exhaust air, the narrow opening area of the intake boat must be larger than that of the exhaust boat.

By the way, if a single intake and exhaust boat is provided, the diameters of the intake and exhaust valves will become large, and their weight will become large, resulting in an inconvenience that the inertial force acting on them will also become large.

Therefore, internal combustion engines have emerged that are equipped with multiple intake and exhaust boats and intake and exhaust valves.In such internal combustion engines, the intake passage connected to each intake valve is opened and closed according to the engine speed and load. This ensures maximum intake inertia effect.

(Problem to be Solved by the Invention) However, in an internal combustion engine that has one intake valve facing approximately the center of the combustion chamber and a plurality of intake valves facing one side of the combustion chamber, each intake valve When opening and closing the intake passage connected to the engine according to the rotational speed, the order of opening and closing becomes a problem. In other words, in the low and medium speed range, if you open the intake passage that connects to the central intake valve facing approximately the center of the combustion chamber,
The intake air flowing into the combustion chamber from the central intake valve collides with the intake air flowing from the other intake valves, reducing the speed of the intake air, which weakens the swirl that occurs within the combustion chamber, leading to a decrease in the combustion efficiency of the intake air. In addition, the internal pressure of the combustion chamber increases, reducing intake air filling efficiency and reducing engine performance.

The present invention has been made in view of the above problems, and its purpose is to improve the combustion efficiency and charging efficiency of the intake air by preventing interference of the intake air in the combustion chamber in the low and medium speed range, thereby improving performance. An object of the present invention is to provide an internal combustion engine capable of achieving the following objectives.

(Means for Solving the Problems) In order to achieve the above object, the present invention includes a central intake valve facing approximately the center of a combustion chamber, and a plurality of intake valves facing one side of the combustion chamber, each intake valve In an internal combustion engine, the intake passages connected to the intake valves are opened and closed depending on the rotation speed and load in the low and medium speed range, and the intake passages connected to the intake valves other than the central intake valve are opened and closed depending on the load in the high speed range. One of its features is that the intake passages connected to all intake valves are opened and closed depending on the load.

(Function) According to the present invention, in the low to medium speed range, the intake passage connected to the central intake valve is closed, so that intake air is forced to flow into the combustion chamber from the intake valves arranged around the central intake valve. , the intake air flowing in from each intake valve does not interfere with each other. Therefore, the flow velocity of the intake air is not reduced, a strong swirl is generated in the combustion chamber, and the combustion efficiency of the intake air is increased, and an increase in the internal pressure of the combustion chamber is prevented, and the filling efficiency of the intake air is kept high. This increases engine performance.

(Example) An example of the present invention will be described below based on the accompanying drawings.

FIG. 1 is a cutaway side view of the cylinder head of the internal combustion engine according to the present invention; FIG. 2 is a plan view showing the intake passage of the internal combustion engine; FIG. 3 is a plan view showing the valve mechanism of the internal combustion engine; Fig. 4 is a view taken in the direction of arrow ① in Fig. 1, Fig. 5 is a sectional view taken along the line v-v in Fig. 4, Fig. 6 is a block diagram showing the configuration of the opening/closing control system of the intake passage, and Fig. 7 is a diagram showing the structure of the intake passage opening/closing control system. It is a graph showing the relationship between the engine rotation number N and the maximum stroke amount S of the opening/closing valve when the throttle is fully opened.

The illustrated internal combustion engine 1 is a four-stroke OHC engine, which has four intake valves 3-3 in a cylinder head 2.
1.3-2.3-3.3-4 and two exhaust valves 4-1
．． It has a score of 4-2.

The intake valve 3-4 is connected to a combustion chamber 40 as shown in FIG.
The other intake valves 3-1.
3-2 and 3-3 are arranged on one side of the combustion chamber 40 so as to surround the intake valve 3-4, as shown in FIG.

Further, the exhaust valves 4-1, 4-2 are arranged so as to face the other side of the combustion chamber 40.

Thus, each intake valve 3-1 to 3-4 and exhaust valve 4-
1.4-2 is urged toward the closing side by springs 5..., 6..., and these are applied to the cylinder by cams 7-1.7-2゜7-3 arranged at the top of the rad 2. .7-4.8
-1.8-2 (see Figure 3), they are opened and closed at appropriate timing. That is, as shown in FIG. 3, camshafts 9, 10.
1 are arranged parallel to each other and rotatable, and the cam shaft has a cam 7-1 for opening and closing the intake valves 3-1 to 3-3.
1 to 7-3 are provided, and the cam shaft 10 is provided with a cam 7-4 that opens and closes the central intake valve 3-4.
cam 8-1. which opens and closes exhaust valve 4-1.4-2.
8-2 is provided. A large-diameter gear 12 is connected to one end of the camshaft 9, and the gear 12 meshes with a gear 13 of the same diameter that is connected to one end of the camshaft 11. A small-diameter gear 14 is connected to the other end of the camshaft 11, and this gear 14 meshes with a gear 15 of the same diameter that is connected to the negative end of the camshaft 10.

On the other hand, as shown in FIGS. 1 and 2, the cylinder head 2 includes an intake passage 16 commonly connected to the intake valves 3-1.3-2, and each intake valve 3-3.3-2. One intake passage 17°18 each connected to 4-1.4 and each exhaust valve 4-1.
Exhaust paths 19, 19 connected to 4-1 are formed.

1 and 2 on the end face of the cylinder head 2.
As shown in the figure, the intake passages 16, 17 and 18 are opened in this order, one end of a spacer 20 is attached to this end face, and a bell mouth shaped opening is provided at the other end of the spacer 20. The funnel 21 having the structure is tied together. The spacer 20 also includes injectors 22 that inject fuel into the intake passages 16, 17.18, respectively, and a Hartz mechanism 23 that opens and closes the intake passages 16, 17.18 according to the engine speed and load. is installed.

Here, the configuration of the valve mechanism 23 will be explained based on FIGS. 4 and 5.

A rectangular plate-shaped slide valve 24 is provided at the end of the spacer 20 to open and close the intake passages 16, 17, 18 by sliding in the left-right direction in FIG. It is covered by 25.

A motor 27 is attached to the cover member 25 via stays 26, 26, and as shown in FIG. The pinion 28 is connected to the shaft 28a of the pinion 28 by a coupling 29. And pinion 2
8 meshes with a rack 24a carved in the slide valve 24 in its sliding direction (perpendicular to the paper plane of FIG. 5), and a rack 24a is connected to the input shaft end of a potentiometer 30. Gear 31 is in mesh.

Incidentally, the driving of the valve mechanism 23 is controlled by a control system shown in FIG. That is, the motor 27 of the valve mechanism 23 is driven by a driver 32, and a control signal is given to the driver 32 from a control unit 33. In other words, the throttle opening detected by the throttle position sensor 34 and the engine rotation speed N detected by the rotation sensor 35 are input to the control unit 33, and the control unit 33 inputs the throttle opening detected by the throttle position sensor 34 and the engine rotation speed N detected by the rotation sensor 35. The drive amount of the motor 27 is determined according to the rotational speed N, and a control signal corresponding to this drive amount is sent to the driver 32.

The control unit 33 also has a map of the maximum stroke amount S of the slide valve 24 with respect to the engine speed N shown in FIG. In the map shown in Fig. 7, the horizontal axis is the engine speed N, and the vertical axis is at full load (
The maximum stroke amount S of the slide valve 24 when the slot is fully open), and the engine rotation speed N is N as shown in the figure.

In the following low speed range (N≦Nl), the maximum stroke MS of the slide valve 24 at full load becomes SI shown in FIG. 4, and the intake passage 16 is fully open at this time. In a partial load state other than a full load state, the intake passage 16 is opened and closed according to the load. That is, the engine rotation speed N detected by the rotation sensor 35 shown in FIG.
is less than N1, the control unit 33 determines the drive amount C of the motor 27 according to the throttle opening (load) detected by the throttle position sensor 34 using the following equation.

C=AxS□ (1) In the above equation, A (≦1) is a coefficient determined according to the engine load (throttle opening), and the motor 27 is rotated by θ according to the drive amount C. When the motor 27 is driven, this rotation is transmitted to the pinion 28 and
8 is rotationally driven, and a slide valve 24 having a rack 24a that meshes with the rack 24a by the rotation of the pinion 28.
is slid within the range of the stroke amount SI, thereby opening and closing the intake passage 16 in accordance with the engine load at that time. Incidentally, the rotation angle θ of the motor 27 is detected by the potentiometer 30, and this detection data is fed back to the control unit 33, and the control unit 33 monitors the drive amount C and the rotation angle θ relative to the drive amount C.

Therefore, in this low speed range, the required amount of intake air flows into the combustion chamber 40 from the intake valves 3-1.3-2, but the intake valves 3-1.3-2 are arranged approximately on the same circumference. Therefore, the intake air flowing into the combustion chamber 40 from these does not interfere with each other, and strong swirls in the circumferential and longitudinal directions are generated within the combustion chamber 40, increasing the combustion efficiency of the intake air. . Furthermore, the internal pressure of the combustion chamber 40 does not increase, and the intake air filling efficiency is maintained high.

On the other hand, in a medium speed range where the engine rotation speed N detected by the rotation sensor 35 shown in FIG. 6 is N, <N≦N2 (see FIG. 7), the slide valve The maximum stroke amount S at full load of 24 is S
2 (see Figure 4). That is, when the slide valve 24 strokes by S2, the intake passage 16.17 becomes fully open, and at partial loads other than full load, the intake passage 16.17 opens the slide valve 2 according to the load at that time.
It is opened and closed by 4. Note that the drive amount C of the motor 27 at this time is calculated using the following equation.

C=AxS2--- (2) Therefore, in this medium speed range, the required amount of intake air flows into the combustion chamber 40 from the intake valves 3-1.3-2.3-3, but in this case Also, since the intake valves 3-1 to 3-3 are arranged approximately on the same circumference, the intake air flowing into the combustion chamber 40 from these does not interfere with each other, and the intake valves 3-1 to 3-3 are arranged on the same circumference, so that the intake air flowing from these into the combustion chamber 40 does not interfere with each other, and as in the low speed range. A strong vertical swirl is generated within the combustion chamber 40, increasing the combustion efficiency and charging efficiency of the intake air, thereby ensuring high engine performance.

In addition, in a high-speed range where the engine rotation speed N detected by the rotation sensor 35 shown in FIG. 6 is N>N2 (see FIG. 7), the slide valve 2 is
The maximum stroke amount S at full load of No. 4 is S3 (
(See Figure 4). That is, 2. When the slide valve 24 strokes by 83, all the intake passages 16, 17, 18 are fully open, and at a partial load other than the full load, the intake passages 16, 17, .
18 is opened and closed by a slide valve 24 depending on the load at that time.

Note that the drive amount C of the motor 27 at this time is calculated using the following equation.

C=AxS,---(3) Therefore, in this high speed range, a required amount of intake air flows into the combustion chamber 4o from all the intake valves 3-1 to 3-4 and is used for combustion.

(Effects of the Invention) As is clear from the above description, the present invention includes a central intake valve facing approximately the center of the combustion chamber, and a plurality of intake valves facing one side of the combustion chamber. In an internal combustion engine in which continuous intake passages are opened and closed according to the rotation speed and load, in low and medium speed ranges, the intake passages connected to the intake valves other than the central intake valve are opened and closed according to the load, and in high speed ranges. The intake passages connected to all intake valves are opened and closed according to the load, which prevents intake air from interfering with the combustion chamber in the low and medium speed ranges, increases the combustion efficiency and charging efficiency of the intake air, and improves the performance of the internal combustion engine. This has the effect of making it possible to improve the performance.

[Brief explanation of drawings]

FIG. 1 is a cutaway side view of the cylinder head of the internal combustion engine according to the present invention; FIG. 2 is a plan view showing the intake passage of the internal combustion engine; FIG. 3 is a plan view showing the valve mechanism of the internal combustion engine; Figure 4 is a sectional view taken along line IV-■ in Figure 1, and Figure 5 is a cross-sectional view of Figure 4.
Figure 6 is a block diagram showing the configuration of the opening/closing control system for the intake passage, and Figure 7 shows the relationship between the engine speed N and the maximum stroke amount S of the opening/closing valve when the throttle is fully open. This is a graph showing. l... Internal combustion engine, 3-1 to 3-4-... Intake valve, 16, 17.18-... Intake passage, 23-... Valve mechanism, 24... Slide valve, 27-... Motor , 30... Potentiometer, 32-... Driver 33... Control unit, 34... Throttle position sensor, 35... Rotation sensor, 40... Combustion chamber.

Claims (1)

[Claims] An internal combustion engine that is equipped with a central intake valve that faces approximately the center of a combustion chamber, and a plurality of intake valves that face one side of the combustion chamber, and that opens and closes the intake passage connected to each intake valve depending on the rotation speed and load. In the low and medium speed range, the intake passages connected to the intake valves except the central intake valve are opened and closed according to the load, and in the high speed range, the intake passages connected to all the intake valves are opened and closed according to the load. An internal combustion engine characterized by: