JPS608338B2 - Fuel injection method for fuel-injected multi-cylinder internal combustion engine - Google Patents

Description

[Detailed description of the invention] The present invention relates to a fuel-injected multi-cylinder internal combustion engine.

An internal combustion engine has been proposed as a gasoline fuel injection type internal combustion engine in which each cylinder is provided with one fuel injection valve, and each fuel injection valve injects fuel into the intake boat of the corresponding cylinder. . Although this type of internal combustion engine has the advantage of making the fuel supplied to each cylinder uniform, it not only does not sufficiently atomize the fuel supplied into the fuel chamber, but also requires a large number of fuel injection valves. In order to solve this problem, one fuel injection valve is installed in the intake manifold gathering part, and the fuel injected from this fuel injection valve is distributed to each cylinder. In this type of internal combustion engine, fuel injection is usually performed in synchronization with the ignition timing or top dead center of each cylinder, or fuel injection is performed regardless of the crank angle position.However, regardless of the crank angle position, Of course, when fuel is injected in synchronization with the ignition timing or top dead center, there is a problem that the distribution of fuel to each cylinder is not uniform.This is illustrated in Figure 7. Fig. 7 schematically shows a four-cylinder internal combustion engine, where K is an intake manifold;
Now the throttle valve, M is the fuel injection valve, N is the intake valve, a,
b, c, and d indicate the first cylinder, the second cylinder, the third cylinder, and the fourth cylinder, respectively. Further, arrows p shown below each cylinder a, b, c, and d indicate the direction of movement of the piston of the corresponding cylinder. The ignition order of the four-cylinder internal combustion engine shown in Fig. 7 is 1-3-4-2, and a, d, g, and j in Fig. 7 are the 1st cylinder a, the 3rd cylinder c, and the 4th cylinder d, respectively. , shows the case where No. 2 cylinder b is at the ignition timing. In Fig. 7a, when the first cylinder a is at the ignition timing, fuel injection is started from the fuel injection valve M, while at this time, the third cylinder c is in the latter half of the intake stroke, and the fourth cylinder d is at the beginning of the intake stroke. . At this time 3
The previously injected fuel is sucked into the incense cylinder c. on the other hand,
As shown in Fig. 7b, by the time the piston of the No. 3 cylinder c starts to rise, a portion of the fuel injected from the fuel injection valve M in Fig. 7a is sucked into the No. 3 cylinder c. . Then, when the intake valve N of the No. 3 cylinder c closes, FIG. 7c? As shown in d, the remaining fuel injected from the fuel injection valve M is 4
It is sucked into cylinder d. Next, as shown in FIG. 7e, when the No. 4 cylinder d starts to rise, a part of the fuel injected in FIG. 7D is sucked into the No. 4 aromatic cylinder d.
On the other hand, when the intake valve N of the No. 4 cylinder d closes, the remaining injected fuel is sucked into the No. 2 cylinder b, as shown in Fig. fgg. Then, as similarly shown in Fig. 7h, when the second aromatic cylinder b starts to rise, a part of the fuel injected in Fig. 7g is sucked into the second cylinder b, and the second cylinder b begins to rise. As shown by i9j, when the intake valve N of the second cylinder b closes, the remaining injected fuel is sucked into the first aromatic cylinder a. Next, as shown in FIG. 7k, when the No. 1 cylinder a starts to rise, a part of the fuel injected in FIG. As shown by a, when the intake valve N of the first cylinder a closes, the remaining injected fuel is sucked into the third aromatic cylinder c. As is clear from the above explanation, when the fuel injection timing is synchronized with the ignition timing, the fuel injected from the fuel injection valve M is distributed and supplied to the pair of cylinders. The same is true even when they are synchronized.However, even when the injected fuel is distributed and supplied to a pair of cylinders in this way, for example, the 4th cylinder d is far from the fuel injection valve M, so Here, only a small portion of the fuel injected from the fuel injection valve M is sucked into the No. 4 cylinder d, while most of the remaining fuel is taken into the No. 2 cylinder b. Since b is close to fuel injector M, a considerable portion of the fuel injected from fuel injector M in g is sucked into No. 2 cylinder b, and the remaining fuel is transferred from fuel injector M. In this way, when the injected fuel is distributed and supplied to a pair of cylinders, the fuel is drawn into the second cylinder b and the third cylinder c, which are close to the fuel injection valve c.
A relatively large amount of fuel is supplied to the cylinders 1 and 4, which are distant from the fuel injection valve c, while a relatively small amount of fuel is supplied to the cylinders 1 and 4, which are distant from the fuel injection valve c. There is a problem with uniformity. An object of the present invention is to provide an internal combustion engine with a simple structure in which injected fuel can be sufficiently atomized, the distribution of fuel to each cylinder can be made uniform, and fuel injection control with good responsiveness can be ensured.

Hereinafter, the present invention will be described in detail with reference to the accompanying drawings.

Referring to Figures 1 and 2, the turtle is the engine body "2
3 is an intake manifold fixed to the engine body, 3 is an intake manifold assembly part, 4 is a substantially horizontal manifold flange arranged above the intake manifold assembly part 3, and 5 is an integrally formed mounting flange 6 at its lower end. "A cylindrical throttle duct 7 with a substantially uniform cross section extending vertically is formed within the throttle duct body 5.

As shown in FIG. 2, the mounting flange 6 of the throttle duct body is connected to the manifold flange 4 through a gasket 8.
Further, a thin-walled cylinder 8 is integrally formed at the lower end of the throttle duct body 5 and projects into the intake manifold gathering section 3.The lower end of this thin-walled cylinder 9 is as shown in FIG. The lower end edge 88 is formed in a knife-edge shape, and the lower end edge 88 is arranged so as to edge out a distance from the inner circumferential wall surface of the intake manifold gathering part 8.In the slot I engine body seal, there is a groove extending in the longitudinal direction of the engine body seal. An extending throttle shaft turtle 1 is arranged, and a butterfly valve-shaped throttle valve body is fixed to the groin of the throttle shaft.Hereafter, for convenience of explanation, we will refer to the throttle valve body located on the side of the engine body as opposed to the throttle shaft shell. The throttle valve body on the opposite side from the right side valve body turtle 2a is called the left side valve body turtle 2, etc. The throttle shaft of the throttle valve turtle 2 is connected to an accelerator pedal in a wheel cab (not shown), and when the accelerator pedal is depressed, the throttle valve turtle 2 is rotated clockwise. On the other hand, a swirl-type fuel injection valve turtle 3 is arranged on the inner wall surface of the throttle duct 7, which is downstream of the throttle valve 12 and located on the side of the engine body. As shown in Fig. 1, the electric heat at the fuel nozzle of this fuel injector 13 is directed downward.Moreover, the distance from the fuel nozzle to the throttle shaft is less than half of the inner orifice of the throttle duct meter. 3 shows a sectional view of the swale type fuel injection valve 33 shown in FIG. 2 to a partially enlarged sectional view of FIG. Then, 2G is a fuel injection valve housing, 8th is a valve holder fixed to the tip of the housing 20, 22 is a needle that can be reciprocated within the valve holder 2 in order to control the opening and closing of the fuel injection port. 23 is a movable core L fixed to the upper end of the movable needle 22; 2 is a compression spring for pressing the movable needle; 25
is the movable core suction solenoid, 26 is the solenoid 251
The connectors for supplying this power are shown respectively. As shown by the broken line in the figure, there is a bag hole 2 in the movable needle 22.
3 and a radial hole 28 are formed, so that in FIG. The fuel flows through the movable needle 22 and the cylindrical inner wall surface 31 of the two valve holders through the intake hole 27 and the radius hole 2 of the movable needle 22.
An annular chamber 32 formed therebetween is supplied. On the other hand, this annular chamber 32 has a pair of radial holes 3 formed in the valve holder 21.
It is connected to a swirling chamber 36 through a three-ring annular chamber 34 and a pair of fuel holes 35 . On the other hand, as shown in FIG. 2, the fuel conduit 29 is connected to a fuel tank 81 via a fuel pump 37. On the other hand, the connector 6 behind the solenoid 2 is connected to an electronic control circuit 39 for controlling the fuel injection timing.
Accordingly, the solenoid 25 is energized based on the output signal of the electronic control circuit 3, and as a result, when the movable needle 22 opens the fuel injection port, the fuel is sent from the fuel conduit 29 into the annular chamber 32 as described above. The fuel flows into the swirling chamber 38 through the radial hole 3, the annular chamber 34, and the fuel hole 36, and is then jetted out from the fuel jet nozzle 4.As shown in FIG. 38, and when the movable needle 22 closes the fuel injection low turtle, the fuel flowing into the swirling chamber 36 from the fuel hole 3 causes a powerful swirl in the swirling chamber 3. Then, this swirling fuel flow flows through the fuel jet port 4 while swirling.
After being ejected, the fuel spreads out due to centrifugal force as shown in Figure 3. In this way, in the swirl-type fuel injection valve blade 3 as shown in FIG. 2 or 3, the fuel is spread while swirling, so that the atomization of the fuel is extremely promoted. Furthermore, it is preferable that the fuel injection angle is within the range of 8' to 120 degrees as indicated by 8 in FIGS. 2, there is further shown a governor mechanism located within the distributor housing.

As is well known, this governor mechanism includes a governor plate 41 that is connected to the engine crankshaft and rotates at half the rotational speed of the crankshaft, and a pair of governor plates that are pivotally mounted on the governor plate 41 by pivot pins 42. A governor weight 43 and a governor cam umbrella 4 rotatably provided with respect to a governor plate 41 are provided, and an operating shaft 45 is fixed on the governor cam turtle 4. On the other hand, a pair of pins are mounted on the governor cam 44. 46 is fixed, and a tension spring 47 is tensioned between the pin turtle 6 and the pivot pin 42.The cam surface 4 of the governor cam 44 and the cam surface 49 of the governor weight 3 are always held by the spring force of the tension spring turtle. When the engine speed increases, the governor weight 43 rotates in the direction of arrow W due to centrifugal force, and the governor cam 4 rotates due to centrifugal force.
The turtle rotates in the direction of the arrow x against the governor plate 4. On the other hand, a disk 8 made of, for example, a magnetic material is fixed on the operating shaft 45, and four notches 6 arranged at equal angular intervals are formed around the disk 5.
Further, a solenoid 52 is arranged opposite to the peripheral part of the disk 59, and one end of the winding of this solenoid 52 is connected to a power source 53.
The end of the terminal is grounded via a resistor 54 and connected to the electronic control circuit 39 via a coupling capacitor 55. When the engine starts operating and the disk 58 rotates, the magnetic flux density inside the solenoid 52 changes every time the solenoid 52 faces the six notches of the disk 58.
The pulse signal indicated by R in the figure is connected to the coupling capacitor 6.
The electronic control circuit 3 is supplied through 5. At the output of the electronic control circuit 39, a fuel injection pulse triggered by the negative pulse of the pulse signal R is generated. The fuel injection action from the fuel injection valve turtle 3 is started. The electronic control circuit 33 is triggered by the negative pulse to generate the fuel injection pulse.
Since this is already well known, it will not be explained in detail here. FIG. 6 shows the intake valve timing & of each cylinder of the internal combustion engine according to the present invention. From FIG. It can be seen that the valve closes five umbrella blades after the bottom dead center.

On the other hand, the solenoid 52 is arranged so that when the engine speed is small, that is, when the advance action by the distributor's cabana mechanism is not performed, the trigger signal for the fuel injection pulse is generated five seconds after bottom dead center. be done. Therefore, when the engine speed is small, the fuel injection action is started from the fuel injection valve 3 in synchronization with the opening operation of the intake valve every 180 degrees of the crank angle. On the other hand, as mentioned above, as the engine speed increases, an advancing action occurs due to the side of the governor, and the governor cam and disk field 0 are also advanced relative to the governor plate 4.
As shown in the figure, the fuel injection start timing 8o, which is synchronized with the intake valve face valve timing, is advanced to the front side of the intake valve closing timing as shown by arrow Z as the engine speed increases.
As shown in Fig. 2, during low-load operation where the relationship between the slosh valve electric current and the throttle duct T is small, the flow velocity of the air flowing between the right side valve body electric 2a and the inner wall surface of the throttle duct T increases. Farther than the flow velocity of the air flowing between the inner wall surfaces, and the right valve weight a and the throttle duct? For example, the airflow that has passed between the inner wall surfaces of the throttle duct 7 once leaves the inner wall surface of the throttle duct 7 as shown by the arrow Q, and then flows again along the inner wall surface of the throttle duct 7.
This has been confirmed by observation using i-len photographs.

Therefore, as shown in FIG. 2, by arranging the fuel injection low crane of the fuel injection valve turtle 3 at a distance downstream from the throttle shaft turtle shaft, the fuel injected from the fuel injection valve turtle 3 is directed by the arrow Q. The air flow shown is forced towards the center of the throttle duct 7, and the injected fuel is thus evenly distributed within the throttle duct 7. In addition, by using the swirl type heat injection valve bone 3, the atomization of the fuel is promoted in the middle. By arranging the fuel injection valve quantity 8 on the side of the right valve body 12a where the airflow passing through is faster, the injected fuel is torn apart by the high-speed airflow, thus further promoting atomization of the fuel. Next, the atomized fuel flows into the intake manifold gathering part 3 together with the intake air, but at this time, the adhered liquid fuel descending on the inner wall surface of the throttle duct flows into the knife-edge-shaped lower edge of the thin-walled cylinder. The liquid fuel is then broken off by the air mixture flow, thus promoting atomization of the liquid fuel adhering to the inner wall surface of the throttle duct.Next, the fuel fed into the intake manifold collecting section 3 is While flowing through the branch pipes, the vaporization of the fuel is further promoted and the fuel is then supplied into the combustion chambers of each cylinder.As mentioned above, fuel is injected from the fuel injection valve 13 in synchronization with the opening of the intake valve. In other words, the fuel injection start timing according to the present invention is shown in Fig. c?
This is the time shown in f9 i,1. Therefore, in this case, while fuel is flowing from the fuel injection valve 83, only one of the four cylinders is injected.
Since only the intake valves of the cylinders are open, all the fuel injected from the fuel injection valve 3 is supplied to one of the four cylinders, thus making the distribution of fuel to each cylinder uniform. It turns out. Furthermore, as the engine speed increases and the flow velocity of the intake air increases accordingly, the relatively heavy fuel ejected from the fuel injector cannot immediately flow into the combustion chamber together with the intake air. As described above, it is preferable to advance the fuel injection timing as the engine speed increases.As described above, according to the present invention, it is possible to equalize the distribution of fuel to each cylinder. Since the vaporization of the fuel is promoted during the process, good combustion can be ensured.

Brief explanation of the drawings: The first diagram is a plan view of the internal combustion engine according to the present invention, the first diagram is a cross-sectional view taken along the Rolo line in the turtle diagram, and the third diagram is a side view of the fuel injection valve in the crab diagram. Cross-sectional view: "Figure 4 is a partially enlarged side cross-sectional view of Figure 3. Figure 5 is a cross-sectional view taken along the line V-V of Figure 6. Figure 6 is a diagram showing the opening timing of the intake valve. 7 is a diagram showing each operating state of the subordinate internal combustion engine.

Box...Intake manifold also 3...Intake manifold gathering part,
7...Throttle duct, Tortoise 2...Throttle valve ~ Tortoise 3...'Fuel injection valve.

Figure 1 Figure 3 Figure 4 Figure 2 Figure 5 Figure 6 Figure 7 Figure 7

Claims (1)

[Claims] 1. 4 fired sequentially with equal crank angle intervals.
The four cylinders are connected to a common intake manifold so that fuel supplied from at least one fuel injection valve is distributed to each cylinder via the intake manifold. A fuel injection method for a multi-cylinder internal combustion engine in which fuel is intermittently injected from a fuel injection valve in synchronization with the closing timing of an intake valve of each cylinder. 2. In the fuel injection method for a fuel injection multi-cylinder internal combustion engine according to claim 1, the fuel injection timing from the fuel injection valve is advanced to the front side of the intake valve closing timing as the engine speed increases. A fuel injection method for a fuel-injected multi-cylinder internal combustion engine.