JPH04128534A - Fuel controller of engine - Google Patents

Abstract

PURPOSE:To prevent misfire caused by a wet ignition due to adhesion of fuel injected from a center port by decreasing a fuel injection quantity fed to the center port from that fed to both side parts as a load becomes smaller, causing poor combustibility. CONSTITUTION:Three intake ports 8-10 which open to a combustion chamber independently from each other are arranged approximately along the crank shaft direction per cylinder in an intake three-valve engine, and respective intake valves are arranged at the opening parts to the combustion chambers of respective intake ports, and also an ignition plug 31 is arranged in the approximate center part of the top area of each combustion chamber. In this case, fuel is injected to the respective intake ports by a means 51. An engine load is detected by a means 42. The means 51 is controlled by a means 52 in such a manner that a fuel injection quantity to a center port 9 among the three intake ports 8 to 10 is decreased from the fuel injection quantity to the side ports 8 and 10 as an engine load becomes smaller when the output of the means 42 is received.

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to a fuel control device for an intake three-valve engine having three intake ports, and particularly to one for injecting and supplying fuel.

(Prior Art) Conventionally, as a fuel control device for a multi-valve engine having a plurality of intake valves for each cylinder, for example, as disclosed in Japanese Utility Model Application Publication No. 1988-131, each cylinder opens independently into a combustion chamber. The main fuel injection valve injects fuel into the center port of the three intake ports, and the auxiliary fuel injection valve injects fuel into the side ports on both sides. By operating only the main fuel injection valve and supplying fuel only from the center port when the engine is operating at low load,
By increasing the degree of stratification within the combustion chamber, and by operating both the main fuel injection valve and the auxiliary fuel injection valve during high-load operation to supply fuel from the three intake ports, a uniform air-fuel mixture is produced. It is known what was made to form.

(Problem to be solved by the invention) By the way, in the so-called multi-valve engine as described in the above publication, due to the configuration of its valve mechanism, the intake valve and the exhaust valve are located on the ~ side and the other side of the combustion chamber, respectively, with approximately camshafts. Since they are arranged along the direction, that is, the crankshaft direction, the openings of the independent intake ports and exhaust ports to the combustion chamber corresponding to the ribs are also arranged in the same way. Therefore, especially in a model with three intake valves, that is, three intake ports, the center port of the three intake ports may be arranged so that it intersects with the center of the cylinder bore on the extension line toward the combustion chamber side. many.

Furthermore, in a multi-valve engine, the spark plug is generally disposed approximately at the center of the top of the combustion chamber, that is, near the center line of the cylinder bore, due to the arrangement of the intake and exhaust valves and combustibility as described above.

Therefore, in a three-valve intake engine, the fuel injected into the central center port tends to collect near the spark plug after flowing into the combustion chamber. In this case,
When the combustibility is poor depending on the engine operating condition, for example, during low load operation, the throttle valve is closed, so the amount of residual gas is large and the air density is low, resulting in poor combustibility.

Also, at low engine speeds, the intake air flow rate is slow and the mixing of air and fuel is poor, resulting in poor spark plug performance. In such a case, if the atomized fuel that flows in from the center port and flies directly toward the ignition plug or the fuel that travels along the wall surface becomes large and adheres to the ignition plug, the ignition plug will get wet and cause a misfire. This will cause further combustibility and will not have a significant adverse effect on engine drivability.

The invention was made in view of these points, and its purpose is to prevent the spark plug from getting wet when combustibility is poor, such as at low load or low rotation speed, in a 3-valve intake engine. The objective is to suppress misfires and improve combustibility, while achieving high air utilization at high loads or high rotations to obtain high output.

(Means for Solving the Problems) In order to achieve the above object, the present invention reduces the amount of fuel injected into the center port during low load or low rotation.

Specifically, the solution taken in the invention of claim (1) is that each cylinder is provided with three intake ports that open into the combustion chamber independently along the direction of the crankshaft, and the combustion of each intake port is An intake valve is disposed at each opening to the combustion chamber, and a spark plug is disposed approximately in the center of the top of the combustion chamber. As shown in FIG. 1, there is a fuel injection means 51 for injecting fuel into each intake port, a load detection means 42 for detecting the engine load, and a load detection means 42 for detecting the engine load. A control means 52 that controls the fuel injection means 5 so that the smaller the fuel injection amount, the smaller the amount of fuel injected into the center port of the three intake ports, compared to the amount of fuel injection into the side ports on both sides thereof. The configuration includes the following.

Moreover, in the invention of claim (2), instead of the load detecting means 42 in claim (1), a rotation speed detecting means 45 for detecting the rotation speed of the engine is provided, and instead of the control means 52,
In response to the output of the same rotation speed detecting means 45, the fuel injection means 51 is controlled so that the lower the engine speed, the smaller the amount of fuel injected to the center port compared to the amount of fuel injected to the site port. The control means 53 is arranged to be biased.

In the invention of claim (3), each cylinder is provided with three independent intake ports that open into the combustion chamber substantially along the crankshaft direction, and each intake port has three independent intake ports that open into the combustion chamber. The target is an engine with 13 intake valves in which an intake valve is provided and a spark plug is provided approximately at the center of the top of the combustion chamber. Of the three intake ports, fuel injection means 54 injects fuel only into the sight ports on both sides, and load detection means 4 that detects the load of the engine.
2, and in response to the output of this load detection means 42, in the low load operating region of the engine, the combustion rate is as low as the intake air! The control means 55 that controls the fuel injection means 54 to inject fuel outside the intake stroke in the high-load operation region of the engine is visible.

Further, in the invention of claim (4), in claim (3), instead of the load detecting means 42, a rotation speed detection means 45 for detecting the rotation speed of the engine is provided, and instead of the first control stage 55, In response to the output of this rotation speed detection means 45, fuel 1, 1 is injected during the intake stroke in the low engine speed range, and fuel is injected outside the intake stroke in the high engine speed range. control means 56 for controlling the fuel injection means 54;
The structure is based on the following.

(Function) With the above configuration, in the invention of claim (1), the control means 52 makes the amount of fuel 11R injected to the center port at the center smaller than the amount of fuel injected to the side ports on both sides at low loads where combustibility deteriorates. Because of this, when operating with low negative G-forces due to combustibility, atomized fuel flows in from the center port and flies directly towards the spark plug! -1 decreases, making it difficult for fuel to stick to the spark plug, preventing misfires due to wetting the spark plug, and improving combustibility. During high-load operation without combustibility problems, the amount of fuel injected into the center port is not reduced compared to the amount of fuel V + injection into the side ports, so the air flowing into the combustion chamber from the center port has no effect on combustion. It is used to improve the air flow rate and ensure high output.

Furthermore, in the invention of claim (2), the first stage control 53 makes the amount of fuel injected to the center port at the center of the engine's rotation range where combustibility deteriorates smaller than the amount of fuel injected to the site ports on both sides. At low speeds where combustibility is poor, as in the case of claim (1), the amount of atomized fuel t1 flowing from the center port and flying towards the ignition plug decreases, making it difficult to adhere to the ignition plug. This prevents misfires due to wet spark plugs and improves combustibility. and,
At high speeds where there is no problem with combustibility, the amount of fuel injected into the center port is not reduced compared to the amount of fuel injected into the side port 1, so the air flowing into the combustion chamber from the center port is effectively used for combustion. High output is TRF due to improved air utilization rate! will be maintained.

Further, in the invention of claim (3), the fuel injection means 54 injects fuel only to the sight ports on both sides of the three intake ports, and the control-1 stage 55 causes the intake stroke to be Inject fuel 11 with 1B
In the load operation range, fuel is injected outside the intake stroke, so in the low load operation closed range where combustibility is poor. The fuel injected to the side port directly flows into the combustion chamber only from the side port, and the fuel flows from the center port with air flowing out, and most of the atomized fuel flies directly toward the spark plug. This prevents fuel from adhering to the spark plug and making it wet, preventing misfires and improving combustibility. Furthermore, in high-load operating ranges, fuel injected into the side port outside of the intake stroke hits the intake valve and rebounds, and a portion of it flows into the adjacent center port, and then into the combustion chamber from the center port during the intake stroke. I will do it. Therefore, the air flowing in from the center port is effectively utilized as a mixture, improving the air utilization rate and ensuring high output.

Furthermore, in the invention of claim (4), fuel is injected only to the sight port as in claim (3), and the control means 56 injects fuel during the intake stroke in the low rotation region and outside the intake stroke in the high rotation region. Therefore, in the low rotation range where combustibility is poor, almost no atomized fuel flows in from the center port and directly hits the spark plug, as in the case of claim (3). Misfires due to salt leakage are prevented and combustibility is improved. Furthermore, in the high rotation range, as in the case of claim (3), the fuel injected outside the intake stroke bounces off the intake valve, and part of it flows into the center port, so the air flowing in from the center port is mixed. The air is used effectively as air, improving the air utilization rate and ensuring high output.

(Example) J': Sid, Examples of the present invention will be described based on the drawings.

FIGS. 2 and 3 show an in-line four-cylinder engine with three intake valves equipped with a fuel control device according to an embodiment of the present invention. Although these figures show only one cylinder as a representative, the other cylinders have the same configuration.

In these figures, 1 is the engine body, 2 is the cylinder block, 3 is the cylinder head joined to the top surface of this cylinder block 2, and 4 is the cam housing disposed on the cylinder/rad 3. be. A cylinder 5 is formed in the cylinder block 2, and a piston 6 is slidably fitted into the cylinder 5. Also, inside the cylinder 5 are two inclined walls 7 on the lower surface of the cylinder spatula F' 3.
A combustion chamber 7 is defined by a, 7b and the top surface of the piston 6.

On the left side of the cylinder bore of the cylinder head 3, there are three independent first to third intake ports 8. which introduce fresh air into the cylinder 5. 9. 10 are provided.

One end of each of the first to third intake ports 8 to 0 opens to the left inclined wall 7a of the combustion chamber 7, and the other end opens to the left side wall of the cylinder head 3. are gathered in. .

The central second intake port (center port) 9 is arranged so that the cylinder bore center is on its extension, and the first and third intake ports (side ports) 8.1
0 is approximately on both sides of the center port 9 in the crankshaft direction.
“They are arranged in rows.

Furthermore, on the right side of the cylinder bore of the cylinder head 3, there are two independent exhaust ports 1.
2, 1.3 are provided. This independent exhaust bow 1-1
2.13 has one end opening at the right side inclined wall 7b of the combustion chamber 7, and the other end opening at the right side wall of the combustion chamber 7, converging into one exhaust port 14 on the right side wall of the combustion chamber 7.

Furthermore, the openings of these two independent V ports 12.1.3 into the combustion chamber 7 are aligned in the crankshaft direction.

The cylinder head 3 has first to third intake ports 8 to
] Three first to third intake valves 1 corresponding to 0 and opening and closing the combustion chamber side openings of the first to third intake ports 8 to 10, respectively.
5.16.17 are provided. Each intake valve 15~
17 has an umbrella-shaped valve head disposed in the opening and a valve shaft extending upward from the valve head, and is slidably fitted into the cylinder head 3 at the valve shaft. It is inserted and can be moved down -F. These intake valves 15~
] A disk-shaped spring seat 18 1 is attached to the end of the valve shaft 7.
8.18 or installed, this spring seat 18.1
Valve springs 19, 19.19 are respectively compressed between 8, 1.8 and the cylinder head 3, and the spring force causes each of the first to third intake valves 15 to 17 to move upward, that is, to close them. It is biased in the direction. And these intake valves 1
5 to] 7 above and extending in the crankshaft direction (cylinder row direction) to the left side of the cam housing 4, and each of the first to third
Three intake cams 20 20 corresponding to intake valves 15 to 17
20 and an integrally formed intake camshaft 21 are provided. Each of the intake valves 15 to 15 is rotated by the intake camshaft 2] or the crankshaft (not shown), so that they come into contact with the intake cams 20, 20. Shasta 22, 22.2
It is driven to open and close at predetermined timing via swing arms 23, 23.23 supported by 2.

Further, two V1 air valves 24 and 25 are provided which correspond to the independent exhaust ports 12 and 13 and open and close the combustion chamber side openings of the independent exhaust ports 121B, respectively. This exhaust valve 2
4.25 is a drive mechanism having the same configuration as each of the intake valves 15 to 17 described above.

That is, the exhaust valves 24, 25 are arranged in the opening with an umbrella-shaped valve head, and are slidably inserted into the cylinder 3 on the valve shaft extending upward from the valve head, and are inserted into the eaves 11 at the top. F movement is possible, and the valve spring 27.27, which is compressed between the spring seat (26.26) attached to the end of the valve shaft and the cylinder head 3, is unable to move in the valve closing direction. energized. And this exhaust valve 24.25
At the upper right side of the cam housing 4, an exhaust camshaft 28 is disposed in parallel with the intake camshaft 21. The exhaust valves 24 and 25 are rotationally driven by the υF gas phase camshaft 2 crankshaft, and are connected to two exhaust cams 29 integrally formed on the exhaust-only camshaft 28.
, 2Q, each end or hydraulic lash adjuster 2
It is driven to open and close at a predetermined timing via swing arms 23, 23 supported by 2.22.

Further, a plug hole 30 is provided in the cylinder head 3 and the cam housing 4 above the combustion chamber 7, and a spark plug 31 has an ignition point 31a in the plug hole 30 with its ignition point 31a located approximately in the middle of the top of the combustion chamber 7. It is installed facing my husband.

An intake passage '-32 is connected to the left side wall of the cylinder head 3 so as to communicate with the intake port 1.

In this intake passage 32, in order from the upstream side, there is a throttle valve 33 for adjusting the intake air port, a surge tank 34 for absorbing intake pulsation, etc., and a sight port 8 and 10 as a fuel directing means 51. A site injector 35 for injecting and supplying fuel I4 and a center injector 36 for injecting and supplying fuel to the center port 9 are provided. The site injector 35 has two nozzles that inject fuel toward the two site ports 8 and 10, as shown by the dashed line in FIG. Intake passage 32 on the side
It has a small nozzle that injects fuel only into the center port 9, and its operation is controlled by the control unit 5.

Further, an exhaust passage 37 is connected to the right side wall of the cylinder head 3 so as to communicate with the exhaust port 4.

Furthermore, in FIG. 3, 40 is a throttle position sensor that detects the opening degree of the throttle valve 33, 41 is an idle switch that outputs an ON signal when the throttle valve 3B is fully open, and 42 is a throttle! - A boost sensor as a load detection means that detects the negative pressure in the intake passage 32 downstream of the double valve 33, 43 a water temperature sensor that detects the engine cooling main temperature inside the water jacket 2a in the cylinder block 2, and 44 a water temperature sensor for the distributor 38. A crank angle sensor 45 detects the crank angle from the rotation signal of the distributor 37, and a rotation speed sensor 45 serves as a rotation speed detection means for detecting the engine rotation speed, and the output signals of these sensors are sent to the control unit 50. has been entered.

Next, the control unit 50 as a control means
The operation control of the site injector 35 and center injector 36 will be explained based on the flowchart of FIG. 4. In the same figure, after starting, in step S1, the engine operating conditions are intake negative pressure PB corresponding to the engine load, engine rotation speed R, and crank angle C.
A is read, and in step S2, the fuel injection amount from the side injector 35 is calculated from the intake negative pressure PB and the engine rotation speed R based on the fuel injection amount characteristic diagrams shown in FIGS. 5 and 6. Site injector 35 corresponding to
Determine the pulse width TS of the activation signal. Similarly, in step S3, the amount of fuel injected from the center injector 36 is calculated, and the nose width Tc of the activation signal of the center injector 36 corresponding to this is determined. Here, the fuel injection characteristics shown in Fig. 5 are as follows: The higher the intake negative pressure P, that is, the lower the engine load, the smaller the amount of fuel injected to the center port becomes by 2 compared to the amount of fuel injected to each side port. Furthermore, the fuel injection characteristics shown in Fig. 6 show that the lower the engine speed, the more the amount of fuel injected into the center port becomes smaller at each side port.
・It is smaller than the amount of fuel injected into. Next, in step S4, it is determined whether the crank angle CA is a predetermined injection start crank angle Is. Here, if the injection start crank angle Is is No, then the crank angle CA or the above I
The system waits until the injection start crank angle Is reaches YES, and proceeds to step S5, where fuel is simultaneously injected from the side injector 35 and center injector 36.
-1 Start injection. Next, the process proceeds to step S6, where it is determined whether the crank angle CA has reached the crank angle at which injection from the center injector 36 ends. This is done by calculating the amount of advance of the crank angle during the period required for the injection at that time from the pulse width Tc of the activation signal of the center injector 36, and then determining whether or not the advance amount has advanced from the injection start crank angle Is. If it is NO that it has not advanced yet, wait until it has advanced and change the crank angle CA or injection path]
If the answer is YES after reaching the crank angle of ', go to step S.
Proceed to step 7 and finish fuel injection from the center injector 36.
'do. Then, in step S8, as in the case of step S6 above, the crank angle CA or
It is determined whether the crank angle has reached the point at which the injection from No. 5 ends.

In this case, the crank angle at which the side injector 35 ends the injection after the center injector 36 ends the injection is determined based on the fuel injection characteristics shown in FIGS. 6 and 7 above.
This is because the amount of fuel injected from the center injector 36 is equal to or less than that, so if the injections are started at the same time and are injected in the same manner, the injection from the center injector 36 will finish first.

In step S8, the crank angle CA has not yet reached the crank angle at which the injection of the side injector 35 ends.
If it is O, wait until it advances and check the crank angle CA or injection path r.
When the crank angle has reached YES, step S9
Proceed to `` and terminate the injection from the sight injector 35.''
Shi, return.

Therefore, in the above embodiment, as shown in the fuel injection characteristics shown in FIG. 5 and FIG. The center injector 36 and the side injector 35 are controlled by $ to make them smaller, respectively.
Therefore, during low-load, low-speed rotation with poor upsizing, atomized water flows in from the center port 9 and flies directly toward the ignition point 3 of the spark plug 3, which is located on its extension. The amount of fuel decreases, and the fuel adheres to the ignition point 31a of the spark plug 310, making it less likely to cause a misfire due to wetting the spark plug, thereby improving combustibility (ignitability). During high-load, high-speed rotation when high output is required without any combustibility problem, the amount of fuel injected into the center port 9 is reduced to the side port 1, as shown in FIGS. 5 and 6.
-8. Since the amount of fuel injected is almost the same and is almost the same as that of 10, the air flowing into the combustion chamber 7 from the center port 9 is effectively used for combustion as an air-fuel mixture. , it is possible to improve air utilization efficiency and ensure high output.

In the embodiment, the fuel injection amount from the Zytoidine J-injector 35 and the center injector 36 may be calculated based only on the fuel injection characteristic diagram shown in FIG. 5, or the fuel injection amount shown in FIG. The calculation may be performed based only on the fuel injection characteristic diagram, and in either case, the same effect as in the above embodiment can be obtained.

In addition, as the fuel injection Ef stage 51, each intake port 8.9
．． Alternatively, one initiator may be provided with a 3-injector injector that supplies 1 J of fuel to each of the intake ports 89 and 10 separately, or a 3-injector type injector may be provided that supplies 1 J of fuel to each of the intake ports 89 and 10, respectively. You may also provide one.

The following FIG. 7 shows another embodiment. In this embodiment, the center 1' and the sictor' 36 are removed from the above embodiment, and the fuel is injected and supplied only to the site ports 1, 8, and 1 [] as the fuel injection means 54. This is the same as the above embodiment. Site-in 2 and Ekta 3 in the control unit 5 [] as a control means in case 2
The motion control of '5a'A'1 will be explained based on the flowchart 1 in FIG. In the same figure, after the start,
In step Q1, the intake negative pressure pB, . Part 1. Then, in step Q2, the pulse width ~'C of the operation signal of the sight injector 352 centered on the fuel injection amount at that time is determined from the above-mentioned intake negative pressure PB and the engine speed R based on a preset value. Next, proceed to step Q3. Based on the intake negative pressure PB and the engine speed R, the crank for starting fuel injection from the site injector 35a is determined based on the fuel injection timing characteristic diagrams shown in FIGS. 9 and 10. Determine the angle CAS. In this case, the injection timing characteristics shown in Fig. 9 are such that fuel is injected during the intake stroke when the intake negative pressure ps is above a certain level, that is, in the normal load or low to medium load range, and outside the intake stroke in the high load range. I am trying to inject fuel with this. In addition, the injection timing characteristics (4
In the low engine speed range, fuel is injected during the intake stroke, and in the high engine speed range, fuel is injected outside the intake stroke. Then, the process proceeds to step Q4, where it is determined whether the crank angle CA has reached the injection start crank angle CAS determined in step Q1.

Here, if the Clark angle CAS for starting injection has not yet been reached and it is ONO, change the crank angle CAS for starting injection.
Wait until the crank angle CAS reaches the injection start crank angle, and if YES, proceed to step Q5 and start fuel injection from the site jetter [35a]. Next, the process proceeds to step Q6, where it is determined whether or not the crank angle CA has reached the crank angle at which injection of fuel IIA from the jetter 35a is completed.

The pulse width VC determined in step Q:l above is used for kneading.
The advance of the crank angle during the period required for the injection at that time;
It is determined whether the crank angle CA has advanced by the amount of advance L1 from the crank angle CAS at the start of the injection. At this point, if the answer is NO that the injection has not progressed, continue the injection until it has progressed, and if the answer is YES that the injection has progressed to the crank angle CA or the crank angle at which the injection ends, proceed to step Q.
7, the injection from the site injector 35a is finished, and the process returns.

Therefore, in the embodiment shown in FIGS. 7 to 1 [] above, fuel is injected and supplied later to the site ports 8 and 10, and the injection timing characteristics are smaller than those shown in FIGS. 9 and 10. As shown in the figure, fuel is injected during the intake stroke when the engine is in the low engine speed range, during the intake stroke when the engine is in the high load and high speed range, and outside the intake stroke when the engine is in the high load and high speed range. In the case of a low-speed CJ with poor performance, the fuel injected from the side injector 35a during the intake stroke flows directly into the combustion chamber 7 only from the side ports 8 and 10, and from the center port 9. Only air flows into the combustion chamber 7, and only air flows into the combustion chamber from the center port 9. Therefore, there is almost no atomized fuel flying directly toward the ignition point 31a of the spark plug 3 located on the extension of the center port 9, and the fuel does not adhere to the ignition point 31a of the spark plug 31 and get wet. It is possible to prevent misfires and improve flammability. Furthermore, in the high angular load height simultaneous rotation region where there is no problem with combustibility and a high 1-force is required, the fuel injected at site ports 8 and 10 outside of the intake stroke will once flow through the intake valves 15 and 16.
It bounced off and some of it hit the neighboring Center Port 9.
and flows into the combustion chamber 7 from the center port 9 during the intake stroke. In this case, the air flowing from the center port 9 is effectively used as an air-fuel mixture for combustion, thereby improving the air utilization rate and ensuring high output.

Incidentally, in the above embodiment as well, the site-in 7 extractor 35
The injection timing of a may be determined based only on the injection timing characteristic diagram shown in FIG. 9, or may be determined based only on the injection timing characteristic diagram shown in FIG. 10. In either case, the same effect as in the above embodiment can be obtained.

(Effects of the Invention) As explained above, according to the fuel control device of the invention of claim (1), the amount of fuel injection to the low-load culm and the central center port, where combustibility deteriorates, is controlled on both sides. Since the fuel injection amount is small compared to the fuel injection amount to the site port, during low load operation, misfires due to the flow of atomized fuel from the center port adhering to the spark plug are prevented, and flammability is improved. In addition, the air flowing in from the three intake ports during high-load operation can be effectively utilized for combustion, thereby achieving both high output and ensuring high output by improving the air utilization rate.

In addition, in the invention of claim (2), the fuel injection port to the central center port is made smaller compared to the fuel injection amount to the sight ports on both sides as the engine speed becomes lower. As a result, at low speeds, it is possible to prevent misfires caused by the atomized fuel from the center port getting wet with stones on the spark plug, improving combustibility, and at high speeds, it is possible to prevent misfires due to the atomized fuel from the center port getting wet with the spark plug. By effectively using the incoming air for combustion, it is possible to achieve high output by improving the air utilization rate.

In the engine fuel control device according to the invention of claim (3), the fuel 1,1 is injected and supplied only to the sight ports on both sides of the three intake ports; Since the fuel is injected during the intake stroke in the region where fuel is injected, and outside the intake stroke in the high-load operating region, fuel is injected into the combustion chamber only from the site port and is injected from the center port in the low-load operating region where combustibility is poor. Without the inflow of rJA atomized fuel, it is possible to improve combustibility by preventing misfires due to the adhesion flow of fuel #4 on the spark plug, and in high-load operating ranges, the fuel injected into the side port is removed from the intake air. Some of the fuel is bounced back by the valve and flows into the adjacent center port, where it flows into the combustion chamber through the three intake ports, improving air utilization and maintaining high output.

Further, in the invention of claim (4), the fuel 11 is injected and supplied only to the sight ports on both sides of the three intake ports, and the injection timing is set in the intake stroke in the low engine speed region and in the high engine speed region. Since the fuel is injected outside the intake stroke, the same problem as in claim (3),
In addition, in the low rotation range where combustibility is poor, it is possible to prevent misfires due to the adhesion of fuel to the spark plug, thereby improving combustibility, and in the high rotation range, it is possible to improve the air utilization rate. Output can be secured.

[Brief explanation of drawings]

FIG. 1 shows a block diagram showing the configuration of the present invention. Figures 2 to 6 show embodiments of the present invention, and Figure 21 is a plan perspective view, Figure 3 is a sectional view taken along line I-1 in Figure 2, and Figure 4 shows the control in the control unit. The flowcharts shown in FIGS. 5 and 6 are characteristic diagrams of the fuel injection amount. FIG. 7 to FIG. 1 [) show another embodiment, FIG. 7 is a diagram corresponding to FIG. 2, FIG. 8 is a 70-chart diagram showing control in the control unit, FIG.
Figure 0 is a characteristic diagram of fuel injection timing. 1 Engine body 7 - Combustion chamber 8 / 1st intake port (sight port!) 9 2nd intake port (seater port)] 0 3rd intake port (sight port) 31 / spark plug '31a / ignition point 32 / intake Passage 35-,. 35a Zyto injector (fuel injection means) 36・Setup>・Jetta (fuel injection means) 42 Boot sensor (load detection means) 45 Rotation speed sensor (rotation speed detection means) 5 [Control unit 51.54 Fuel injection means 52, 53. 55. 56...Control means path 4 Figure

Claims (4)

[Claims] (1) Three intake ports that open into the combustion chamber independently are provided for each cylinder approximately along the crankshaft direction, and an intake valve is provided at the opening of each intake port to the combustion chamber. In addition, in the three-intake valve engine in which the spark plug is disposed approximately at the center of the top of the combustion chamber, fuel injection means for injecting fuel into each of the intake ports; load detection means for detecting the load of the engine; Based on the output of this load detection means, the smaller the engine load, the smaller the amount of fuel injection to the center port among the three intake ports mentioned above compared to the amount of fuel injection to the side ports on both sides. A fuel control device for an engine, comprising: control means for controlling the fuel injection means. (2) Each cylinder is provided with three intake ports that open into the combustion chamber independently along the direction of the crankshaft, and an intake valve is provided at the opening of each intake port to the combustion chamber. In addition, in the three-intake valve engine in which the spark plug is disposed approximately at the center of the top of the combustion chamber, there is provided a fuel injection means for injecting fuel into each of the intake ports, and a rotation speed detection means for detecting the rotation speed of the engine. Based on the output of this rotational speed detection means, the lower the engine rotational speed, the more the fuel injection amount to the center port is compared to the fuel injection amount to the side ports on both sides of the three intake ports. 1. A fuel control device for an engine, comprising: control means for controlling the fuel injection means so as to reduce the fuel injection means. (3) Three intake ports that open into the combustion chamber independently are provided for each cylinder approximately along the crankshaft direction, and an intake valve is provided at the opening of each intake port to the combustion chamber. In addition, in the three-valve intake engine in which the spark plug is disposed approximately at the center of the top of the combustion chamber, a fuel injection means for injecting fuel only into the side ports on both sides of the three intake ports; A load detection means for detecting the load, and a system configured to receive the output of the load detection means and inject fuel during the intake stroke in a low-load operating range of the engine, and inject fuel outside the intake stroke in a high-load operating range of the engine. A fuel control device for an engine, comprising: control means for controlling the fuel injection means. (4) Three intake ports that open into the combustion chamber independently are provided for each cylinder approximately along the crankshaft direction, and an intake valve is provided at the opening of each intake port to the combustion chamber. In addition, in the three-valve intake engine in which the spark plug is disposed approximately at the center of the top of the combustion chamber, a fuel injection means for injecting fuel only into the side ports on both sides of the three intake ports; A rotation speed detection means for detecting the rotation speed; and a system that receives the output of the rotation speed detection means and injects fuel during the intake stroke in a low engine rotation region, and injects fuel outside the intake stroke in a high engine rotation region. and a control means for controlling the fuel injection means.