JPS6011211B2 - Fuel injection system for even-numbered cylinder engines - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an injection type fuel supply system for a gasoline engine with four or more even-numbered cylinders, and particularly relates to a fuel supply system configured to uniformly distribute fuel among each cylinder. .

As disclosed in Japanese Patent Application Laid-Open No. 53-1723, an electrically controlled fuel injection valve is installed near the intake valve of each cylinder of an engine equipped with multiple cylinders, and the same amount of fuel is injected into each cylinder under certain operating conditions. A device configured to supply fuel from a fuel injection valve has already been put into practical use.

This injection type fuel supply system that has been put into practical use uses a 4-stroke gasoline engine, but the number of cylinders is 4,
There are examples where cylinders 6 and 8 are often used, and up to 12 cylinders are used. In these injection type fuel supply devices, the fuel injection valve is installed near the intake valve of each cylinder as described above, so the fuel injection valve is installed near the intake valve of each cylinder. A substantially uniform amount of fuel is inhaled during the intake stroke. However, in both cases, fuel is simultaneously injected once per engine revolution from the fuel injection valves installed in each cylinder, so each cylinder is supplied with fuel during various processes, and fuel is supplied at the optimum time for each cylinder. may not necessarily be provided. This creates a problem when the engine is running at high speeds. Since such a conventional fuel supply system requires a fuel injection valve for each cylinder, it is costly and requires a lot of time to install.

To overcome this drawback, attempts have been made to install a single fuel injector in the upstream intake passage where multiple cylinders diverge, but this reduces the uniformity of fuel distributed to each cylinder. . This is because it becomes more difficult to make the airflow uniform among multiple cylinders as the number of cylinders increases, and fuel distribution also deteriorates. In this case, fuel is injected the same number of times as the number of cylinders during two rotations of the engine, and during the intake stroke of each cylinder, but as mentioned above, the airflow between the cylinders is not equal, so the fuel is distributed unevenly. It is not possible to eliminate the disadvantage of becoming. An object of the present invention is to provide an injection type fuel supply device suitable for supplying a uniform amount of fuel to each cylinder of an even-numbered engine with four or more cylinders, and its features include:
Four or more cylinders that operate without duplication of the same process are divided into two groups with even-numbered and odd-numbered operating orders, and are connected to two intake passages, and a throttle valve and each cylinder are connected to each intake passage. This is achieved by connecting an intake regulating valve section equipped with an intermittent fuel injection valve that injects fuel in response to the intake stroke of the cylinder.

FIG. 1 is a plan view showing an injection type fuel supply system for a six-cylinder engine, which is an embodiment of the present invention. 1 is a six-cylinder engine, and a cooling fan 7 is attached to the end of the engine.

This engine has first to sixth cylinders installed from the cooling fan 7 side, and their mounting positions are indicated by numbers 1 to 6. The cylinders 1 to 3 and the cylinders 4 to 6 are integrated into two intake manifolds 2, which are connected to a vertically mounted intake regulating valve section 3.

FIG. 2 is a vertical sectional view of the intake air regulating valve section of FIG. 1, in which the same parts as in FIG. 1 are given the same reference numerals.

An intake regulating valve part 3 is installed on the end face of the intake manifold 2 on the intake inlet side.
is installed, and a throttle valve 8 for adjusting the amount of intake air is rotatably mounted inside the intake air regulating valve section 3. A throttle valve stem 4 to which the throttle valve 8 is fixed extends outside the intake cylinder and is connected to another throttle valve shaft 4 by a connector 5 shown in FIG. That is, 2
The relationship between the two throttle valves 8 is increased or decreased in conjunction with the operating state of the six-cylinder engine, and the opening and closing operations are performed by the driver. A fuel injection valve 6 is attached downstream of the throttle valve 8. FIG. 3 is a graph showing the process of the six-cylinder engine shown in FIG. 1, with the leftmost column showing the cylinder number and the top column showing the rotation angle of the crank.

The shaded area in each cylinder column indicates the intake stroke, which corresponds to an interval of 180 degrees in terms of crank rotation angle. However, it is well known that in actual intake valve operation, the valve opens just before the shaded area and opens immediately after the shaded area. Since the 1st to 3rd cylinders are operated at different crank rotation angles of 240°, the intake operation is performed at 1200 different crank rotational positions.

In other words, the three cylinders operate in a well-balanced manner. On the other hand, the crank rotation angle for 4 to 6 cylinders is 240 at the same time.
o It forms a well-balanced group that operates at different times, and operates so that the same operation does not overlap with groups 1 to 3, so if the fuel injection is appropriate, this 6-cylinder engine rotates smoothly. 6 from the fuel supply device configured in this manner and the fuel injection valve at one location as described above.
Let's compare and examine the device that supplies fuel to the cylinders.

When there is one fuel injection valve, there is also one intake manifold 2 and one intake adjustment valve part 3, so fuel is injected six times during two engine revolutions so that fuel is distributed as evenly as possible to all intake cylinders. Injection takes place. At this time, fuel injection is performed every 120 degrees of crank rotation angle. Therefore,
Assuming that fuel injection is started at the time when each intake stroke begins (as mentioned above, when the piston begins to descend for intake, not when the intake valve begins to open), this injection start time is determined by the crank rotation. corner oo, 120o, 24
It is at 0o, 3600, 480o, 6000. An electromagnetic type injection valve is used as the fuel injection valve 6, and the amount of fuel supplied by this injection valve is determined by the valve opening time.

Engine or constant torque operation (constant manifold pressure)
When operated, approximately equal amounts of fuel are required each time. That is, it is necessary that the engagement times of the fuel injection valves be equal. Furthermore, the injected fuel must be completely supplied to the engine before the next injection starts.
If the maximum operating speed of the engine is 600 pm, then 3
．． The maximum amount of fuel must be ejected once every 3 milliseconds. This suggests that the following problems will occur. That is, during high speed rotation, fuel is injected over a wide crank rotation angle range, and during low speed rotation, fuel is injected over a very short rotation angle range.

The six cylinders in this case are 1, 5, and 3 as shown in Figure 3.
, 6, 2, and 4 are arranged to operate in this order. First, when considering low speed rotation, the crank rotation angle is oo
Since the first cylinder is not in the suction stroke, most of the fuel injected at this time is sucked into the third cylinder, which is in the suction stroke. Similarly, the fuel injected at 120o is injected into the 6th cylinder, the fuel injected at 240o into the 2nd cylinder, the fuel injected at 360o into the 4th cylinder, the fuel injected at 4800o into the 1st cylinder, and the fuel injected at 600o. The fuel is sucked into the fifth cylinder. That is, when the engine is rotating at a low speed, the amount of fuel injected is small and the injection is completed in a short time, so there is no problem even if the fuel is injected from one location. However, at high speed rotation, fuel is injected over a wide rotation angle range (within 1200 degrees), so the direction of the airflow changes while passing through the intake manifold 2, and the fuel enters the two cylinders.

That is, the fuel injected at the crank rotation angle oo initially rides on the airflow flowing into the third cylinder and is sucked in, but gradually comes to be sucked into the sixth cylinder. In this case, as can be seen in FIG. 1, fuel is supplied to the third and sixth cylinders, which are two cylinders apart. Next, the fuel injected at a crank rotation angle of 240o is initially supplied only to the second cylinder, but gradually moves to the fourth cylinder, and finally comes to be supplied only to the fourth cylinder. That is, in this case, as seen in FIG. 1, fuel is sucked into the second and fourth cylinders, which are one space apart. In addition, the fuel injected at a crank rotation angle of 360 initially flows only into the first cylinder, and then gradually flows into the fifth cylinder.
Fuel is supplied between two separate cylinders. In this way, during high-speed operation, the interval between the two cylinders into which fuel is taken changes, so the airflow changes over time and fuel distribution tends to become uneven. Furthermore, as mentioned above, the fuel injection time is limited to 3.3 milliseconds or less, which makes it difficult to inject a large amount of fuel in a short period of time using an extremely fast-acting and expensive fuel injection device. This will cause problems.
However, in the fuel supply system of this embodiment shown in FIG. 1, the fuel injection period is every 2400 crank rotation angles, so at 600 pm, the fuel injection period is 6.67 milliseconds.

If this is the case, a relatively inexpensive electromagnetic fuel supply valve that is commonly used at present can be used satisfactorily. Also, as shown in Fig. 3, the cylinders are operated in the order of 1, 5, 3, 6, 2, 4, and the 1st to 3rd cylinders are in the 1st group, and the 4th to 6th cylinders are in the 2nd group. and the first group has a crank rotation angle of 12
Since fuel is injected at 0o, 3600, and 6000, and fuel is injected at 00, 2400, and 4800 in the second group, there is no duplication of intake strokes. Also, regarding the first group, ``The airflow direction does not change significantly because the intake process moves to the next cylinder in the order of 3rd cylinder, 2nd cylinder, and 1st cylinder. However, when it moves from 1st cylinder to 3rd cylinder. Although the airflow direction changes relatively significantly when the two cylinders are placed, the direction of the airflow does not change that much because the cylinders are adjacent to each other.This is also true between the cylinders in the second group.
Since cylinders in the intake stroke are alternately present in the first group and the second group, even when the engine is operated at high speed, there is little variation in the intake air flow, and smooth operation is possible. As described above, the electric fuel supply system of this embodiment operates so that the strokes of four or more cylinders do not overlap, is divided into two groups, is connected to two intake passages, and is installed upstream of the intake passage. By providing the fuel injection valve in the air regulating valve section, it is possible to supply uniform fuel to each cylinder at any rotation speed.

Note that each cylinder takes in air in different groups alternately, so an even airflow always flows through the intake manifold.

Furthermore, by dividing each cylinder into two groups, it is possible to use the inexpensive electromagnetic fuel supply valves that are currently widely used, and the engine runs smoothly, making effective use of fuel and purifying exhaust gas. It has the advantage of The fuel injection device of the present invention has the effect of being able to supply uniform fuel to each cylinder in a timely manner.

[Brief explanation of drawings]

Fig. 1 is a plan view of an injection type fuel supply system for a six-cylinder engine which is an embodiment of the present invention, Fig. 2 is a vertical sectional view of the intake regulating valve section of Fig. It is a graph showing the process of a 6-cylinder engine. 1... 6-cylinder engine, 2... Intake manifold, 3... Intake adjustment valve section, 6... Fuel injection valve, 8... Throttle valve. Hair 1 figure Hair 2 figure Tsutomu 3 figure

Claims (1)

[Scope of Claims] 1. In a four-cycle engine having four or more even-numbered cylinders that operate without duplication of the same process, the even-numbered cylinders are divided into groups of even-numbered cylinders and odd-numbered cylinders whose operating order is as follows: a first supplying air to the even-numbered cylinder groups;
a second supplying air to the intake passage and the odd-numbered cylinder groups;
A fuel injection device for an even-numbered cylinder engine, wherein an intake passage is provided, and a throttle valve and an intermittent fuel injection valve for injecting fuel corresponding to the intake stroke of the even-numbered cylinders are arranged in each of the first intake passage and the second intake passage. 2. In claim 1, the even-numbered cylinders are 6
The first intake passage and the second intake passage are a combination of three cylinders in which the same process is operated at positions with crank angles different by 240 degrees, and the fuel injection valve is an integration of six cylinders. A fuel injection device for even-numbered cylinder engines that injects fuel in synchronization with the intake stroke of the engine.