JPS5990717A - Intake device for 4-cycle internal-combustion engine - Google Patents

Abstract

PURPOSE:To permit the titled device to improve a fuel atomization in all operating ranges, by providing one of plurality of intake passages communicating each other around an intake valve with a regulating valve adapted to open and close in response to operating conditions, in a 4-cycle internal-combustion engine having three adjacent intake valves provided on every cylinder. CONSTITUTION:A regulating valve 44 is closed to withdraw an intake air from an intake passage 40a to a communicating chamber 46 while a vehicle is operated under a reduced load and low speed. By closing an intake valve 20, the intake air produces a violent turbulent. As a result, a fuel injected into the communicating chamber 46 is quickly atomized and when the intake valve 20 is opened the fuel enters into a combustion chamber 16 as a consistent fuel-air mixture. On the other hand, while the vehicle is operated under an increased load and high speed, the regulating valve 44 is opened for guiding the intake air from intake passages 40a, 40b to the communicating chamber 46. In consequence, the fuel injected through an injection valve 48 is diffused inside the communicating chamber 46 to lower the amount thereof that deposits on an inner wall. In this manner, the atomization of fuel is facilitated. By arranging as described above, the fuel can be better atomized under all operating conditions, and thereby improving the combustion of fuel.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a four cycle internal combustion (Kineki) intake system which has three intake valves adjacent to each other for one cylinder and injects fuel into the intake passage. .

There is a four-cycle internal combustion engine in which three adjacent intake valves are provided for one cylinder. When one fuel injection valve is used for one cylinder in this type of engine, the mounting position of the injection valve has a large effect on combustion. For example, it is conceivable to connect the downstream side of one intake passage to three intake valves and inject fuel into this intake passage. However, in this case, the cross-sectional area of the intake passage is not large, and the intake flow velocity is small during low-load, low-speed operation, so fuel tends to adhere to the inner wall of the intake passage and form a wall flow, resulting in the problem of worsening fuel atomization. arise.

Therefore, it is conceivable to provide three intake passages independently for each intake valve, and to open and close some of the intake passages according to operating conditions such as operating load and speed. However, in this case, if you try to supply fuel from one fuel injector, one for low load and low speed will be used.
If fuel is injected into only one intake passage, the result will be . If all the intake passages are opened at high speeds, the fuel will be distributed non-uniformly within the combustion chamber, resulting in poor combustion.

The present invention has been made in view of the above circumstances.
The purpose of the present invention is to provide an intake system for a four-stroke internal combustion engine that can improve fuel Nj in all operating ranges and improve and stabilize combustion even though multiple fuel injection valves are used. do.

In order to achieve this object, the present invention provides a four-stroke internal combustion engine having three intake valves that are in contact with each other at one angle for one cylinder, including an outstanding number of intake passages communicating with the intake valves, and a plurality of intake passages in the vicinity of the intake valves. A communication chamber that communicates the intake passages with each other, and a fuel injection valve that is provided in the communication chamber and injects fuel toward the central intake valve, and at least one of the intake passages is opened and closed according to operating conditions. It is equipped with a control valve.

The present invention will be described in detail below based on the illustrated embodiments.

? :] Fig. 1 is a partially sectional plan view of the first embodiment of the present invention, Fig. 8152 is a sectional view taken along the line ■-■, and Fig. 3 is a torque characteristic diagram. In FIGS. 1 and 2, numeral 10 is a 7 cylinder body, 12 is a cylinder head, and 14 is a piston.
A combustion chamber 16 is formed by these. The cylinder head 12 has two exhaust valves 18 (18a, 18
'b) and three mutually adjacent intake valves 20 (20a
, 20b, 20c) are provided. These exhaust and intake valves 18 and 20 are opened and closed by a known double overhead camshaft type valve mechanism comprising overhead camshafts 22, 24, rocker arms 26, 28, etc., respectively. 30 is a rad cover to the cylinder, 32 is an exhaust passage communicating with the exhaust valve 18, and the first
In the figure, 34 is a spark plug.

36 is a surge tank, 38 is a surge tank 3 for each generous
6 and the cylinder head 12. Inside the intake pipe 38 is a first intake passage 40a.

A second intake passage 40b is formed. First intake passage 4
0a and the second intake passage 40b have approximately the same diameter, and these passages 4. A butterfly-shaped control valve 44 that opens and closes the second intake passage 40b is attached to the valve shaft 42 that passes through Oa and 40b. This control valve 44 is controlled to open and close in response to operating conditions, such as increases and decreases in operating load and engine speed.

The downstream side of the intake passage 40 is connected to a communication chamber 46 provided in the cylinder head 12, and this communication chamber 46 is connected to the three intake valves 2.
Connects to 0.

48 is an electric fuel injection valve. This injection valve 48 is the second
As shown in the figure, the distribution pipe 5 disposed at the upper part of the intake pipe 38
0 and the two parts of the communication chamber 46 of the cylinder 12, and its injection port is directed toward the central intake valve 20b.

This injection valve 48 is opened at a predetermined timing by an electric signal output from a controller (1'', I not shown), and the fuel inside the distribution pipe 50 pressurized to a predetermined pressure is injected into the communication chamber 46. Sprays intermittently.

The operation of this 2131 embodiment is as follows. low 1'
During load/low speed operation, the control valve 44 is closed and the first intake air is closed.
Intake air is guided to the communication chamber 46 from the η path 40a.

During low-speed operation, the pulsation of the intake air is large, and the first intake air, m'
(Since the passage 40a has a small diameter, the intake inertia is also large. Therefore, when the intake valve 20 is closed, the intake air enters the jTV passage chamber 46 from the first intake passage 40a and generates strong turbulence.
The fuel that was injected intermittently at No. 6 was quickly and well atomized and homogenized by 1t:' due to the turbulent flow of air! :
L': Aiki occurs and the combustion chamber 16 opens as the intake valve 20 opens.
flows into. At this time, the turbulent flow within the communication chamber 46 also strengthens the snorl, and combustion can be stabilized.

During high load/high speed operation, the control valve 44 opens and the intake air is y'
, 41, enters the communication chamber 46 from the second intake passages 40a, 40b. Fuel is injected from the injection valve 48.
1 diffuses within the relatively wide communication chamber 46 over a long distance η1f without hitting the inner wall. This reduces the amount of fuel adhering to the inner wall and promotes atomization of the fuel.

In FIG. 3, the solid line A represents the torque characteristic when the control valve 44 is kept open, and shows that the torque decreases significantly due to the decrease in the intake inertia effect at medium and low speeds.

By combining these two characteristics A and B, it is possible to improve the torque characteristics by combining the two characteristics A and B according to the torque characteristics diagram for the case in which the control valve 44 is closed.

Figure ε114 is a partially sectional plan view of the second embodiment.

This embodiment is similar to the first intake passage 4 in the first embodiment.
0a is formed to have a smaller diameter than the 332 intake passage 40b. According to this embodiment, the injection port of the injection valve 48 is agl.
, m2 intake passage 4.0 a, 401) from υ5C between 2] S2 intake passage 4. The number of deviations is Ob.

As a result, when the control valve 44 opens under high load and high speed, the intake air flowing into the communication chamber 46 from the second intake passage 401) is 8i'
! : Compared to the first embodiment, less water was injected from the injection valve 48.
centre? j - better contact and atomization of the fuel is further promoted. In addition, since the second intake passage 40b has a small diameter, 8['
Compared to the lj1 actual/J'fH example, it is possible to increase I-lux due to intake inertia from a lower speed. Furthermore, since the amount of deviation of the first intake passage 40a with respect to the communication chamber 46 is larger than that in the first embodiment, the vortex generated in the communication chamber 46 becomes even stronger at low speeds when the control valve 44 is closed, and the intake air When the valve 20 is opened, an even stronger swirl (suction vortex) is generated within the combustion chamber 16 due to this vortex. This /ζ stabilizes combustion at low speeds, making the effect of smoothing low speed operation even more noticeable.

FIG. 5 is a partially sectional plan view of the third embodiment. In this embodiment, the coffin 1 intake passage 40a is arranged in the center, while the second intake passage 40b is divided into two, each with a control valve. 4
4.44.

According to this embodiment, the intake air passing through the first intake passage when the control valve 44 is closed at low load and low speed hits the fuel injected from the injection valve 48 well, and the atomization is particularly good at low load and low speed. This is further improved compared to the first and second embodiments.

FIG. 6 is a partially sectional plan view of the fourth embodiment, and this embodiment is similar to the first embodiment. Second. Third intake passage 40a.

40b and 40c, and 9' sandwiching the first intake passage 40a.
, '42+, the third intake passages 40b, 40c are provided with control valves 44a, 44b whose opening and closing timings differ from each other.

According to this embodiment, as in the third embodiment (Fig. 25), not only atomization at low speeds is promoted, but also torque characteristics can be improved at the same time. That is, FIG. 7 is a torque characteristic diagram of this fourth embodiment, and the actual MA in this diagram is the control valve 44a.
, 44b are kept open, and the broken line B shows the characteristics when both control valves 44a and 44b are closed in the low speed range, and the chain f! iIc is the characteristic when only the control valve 44'b is opened in the medium speed range.

By opening and closing the control valves 44a and 44b at different operating speeds and combining these characteristics A, B, and C, it is possible to: 1) improve torque in the medium speed range compared to Examples 1 to 3; be able to.

, ko (Figure 18 is a partially sectional plan view of the fifth embodiment, and this embodiment is the same as that of the fourth embodiment (Figure 6)) by swapping the positions of the intake passage 40a and the second intake passage 40b. It is something that

According to this embodiment, as in the fourth embodiment (FIG. 6), not only can the torque in the medium speed range be increased, but also r'+i
Note i': j': As in the second embodiment (FIG. 4), the swirl is strengthened in the low speed range, so rotation during low speed operation becomes even smoother.

In addition, Boo! '; In Figures 4, 5, 6, and 8, the same parts as in Figure 1 are designated by the same symbols 4.j, so the explanations will not be repeated.

As described above, the present invention allows a plurality of intake passages to communicate with each other through communication chambers provided near three intake valves, and injects fuel into the communication chamber oriented toward the central 11 branch valves. A control valve was provided in the intake passage, and the control valve was configured to open and close depending on the operation and the increase/decrease of the reverse rotation speed. Therefore, when the load is low and the engine speed is low, the control valve closes and the intake air passes through only a portion of the intake passage, making it possible to effectively utilize intake inertia to improve air supply efficiency and increase output. At this time, a strong turbulent flow is generated in the communication chamber due to the intake pulsation, and the fuel injected into the communication chamber is mixed well with the intake air due to this turbulence, and atomization of the fuel is promoted. This wasteful combustion is improved and fuel efficiency can be improved. Note that the turbulent flow in the communication chamber also strengthens the turbulence (swirl) of the intake air flowing into the combustion chamber, reducing fluctuations in combustion from cycle to cycle and making operation easier.

On the other hand, the fuel is injected obliquely near the center of the communication chamber, so the injected fuel can spread over a relatively long distance without hitting the inner wall, and the atomization of the fuel is favorable under all operating conditions. This makes it possible to improve combustion and fuel efficiency.

[Brief explanation of the drawing]

Fig. 1 is a partially sectional plan view of the first embodiment, 2M is an n-n1 sectional view thereof, Fig. 3 is a torque characteristic diagram, and Fig. 4.5
．． Figure 6 is the second. Third. A partially sectional plan view of the fourth embodiment, and FIG. 7 is a torque characteristic diagram of the fourth embodiment, 'i!
Figure A8 is a plan view of part i:'f' of the fifth embodiment. 20... Intake valve, 40... Intake passage, 44... Control valve, 46... Communication chamber, 48... Fuel injection valve. Patent applicant Yamahachi Motor Co., Ltd.

Claims (1)

[Claims] In a four cycle internal combustion engine having three intake valves adjacent to each other for one intake valve, a plurality of intake passages leading to the intake valve, a communication chamber communicating the intake passage near the intake valve, and A fuel injection valve is provided in the communication chamber and injects fuel toward the central intake valve (iii) At least one of the intake JUL paths is provided with a control valve that opens and closes depending on operating conditions Intake system for 4-cycle internal combustion engine.