JPS6361712A - Intake device for engine - Google Patents

Abstract

PURPOSE:To improve charging efficiency by providing an auxiliary intake port which is closed to the open air and communicates with other cylinders besides and intake port for supplying intake air in each combustion chamber, and establishing the opening time of the auxiliary intake port to be earlier than that of the intake port for supplying the intake air. CONSTITUTION:The combustion chamber of each cylinder 2 has an intake port 6 which communicates with an air cleaner 14 and makes air intaking action, and is provided with an auxiliary intake port 9 which communicates mutually with other cylinders through a communicating passage 22 closed to the open air and an intake air diffusing chamber 21 besides said intake port 6 in each combustion chamber. The opening time of said port 9 is established to be earlier than that of said port 6. Thus pressure vibration generated in the communicating passage 22 can produce dynamic effect in said port 6 through the combustion chamber to improve charging efficiency through synergetic action with the dynamic effect in an intake system.

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to an intake system for an engine that utilizes the dynamic effect of intake air to improve charging efficiency.

(Prior Art) Various engine intake devices have been known that utilize fluctuations in intake pressure as the engine operates to increase intake air filling efficiency. For example, JP-A-59-1735
In the device disclosed in the October bulletin, the intake manifold is divided into a plurality of cylinder groups whose intake order is not adjacent to each other, and the intake passages are merged upstream of each intake manifold assembly. The intake passages between the sections and between each intake manifold assembly section and the above-mentioned merging section are communicated via volume sections, and a first opening and a second opening m are provided at these two communication sections. Valves are provided, and the opening and closing of these valves are controlled according to the operating conditions of the engine.

According to this device, when the double-opening valve is closed and
When only the second on-off valve is opened and when the first on-off valve is opened, the inverse %1 position of the intake pressure wave changes in stages, and the actual length of the passage related to the period of pressure oscillation changes. Since the speed changes, it is possible to enhance the dynamic effect and improve the filling efficiency at low speed, medium speed, and ^ speed Meijo.

However, in such conventional devices, the intake passage (the intake manifold and the intake passage upstream of the intake manifold), which is the flow path for supplying intake air introduced from the outside to each cylinder, is
Incorporating a structure to provide the above-mentioned dynamic effects complicates the intake system, limits the length of the intake passage, and places restrictions on the layout of the intake system.

Furthermore, if only the intake passage through which intake air is supplied has a dynamic effect, there is a limit to the degree of freedom in adjusting the dynamic effect according to the required operating range and the degree to which the charging efficiency can be improved.

(Objective of the Invention) In view of the above circumstances, the present invention has been developed to provide a dynamic system that uses pressure propagation between cylinders or between cylinders and an intake expansion chamber that is closed from the outside air, in addition to the original intake system that supplies intake air. By providing an auxiliary system that has an effect, the structure of the intake system can be simplified, the filling efficiency can be improved, etc. The present invention provides an intake device.

(Structure of the Invention) The present invention provides, in addition to an intake port that supplies intake air to a combustion chamber,
An auxiliary intake port opened during the intake stroke and this auxiliary intake port communicated only with the auxiliary intake bow 1 of other cylinders,
Alternatively, a communication path is provided to communicate with the closed intake expansion chamber from the outside air, and the opening timing of the auxiliary intake port is set earlier than the opening timing of the intake port.

With this configuration, apart from the original intake system that supplies intake air, pressure oscillations are generated in the communication passage connected to the auxiliary intake port, producing a dynamic effect. In particular, the auxiliary intake port opens earlier than the intake port. By this, the Lf force vibration in the communication passage is strengthened due to the influence of the residual exhaust pressure, and the dynamic effect is enhanced.

(Embodiment) FIGS. 1 and 2 show a first embodiment of the present invention, and in this embodiment, the present invention H1li is applied to a 4-cylinder, 4-recycle reciprocating engine. In these figures, a combustion chamber 4 is formed above a piston 3 in each cylinder 2 of an engine main body 1.

The combustion chamber 4 is opened and closed by an intake valve 5.
An intake port 6 that supplies intake air to the exhaust port 6 and an exhaust port 8 that is opened and closed by an exhaust valve 7 are opened.
An auxiliary intake port 9 is opened to enhance the dynamic effect of intake air. This auxiliary intake valve 1-0 is the auxiliary intake valve 10.
It is opened during the intake stroke.

The intake port 6 of each cylinder 2 is connected to an intake passage 11 for each cylinder, and this intake passage 11 for each cylinder is connected to an upstream intake passage 1
2 is connected to a surge tank 13 into which outside air is introduced. The upstream intake passage 12 is provided with an air cleaner 14, an air flow meter 15, and a throttle valve 16, and the intake passage 11 is provided with a fuel injection valve 17. Further, the exhaust port 8 is connected to an exhaust manifold 18.

On the other hand, the auxiliary intake port 9 is connected to an intake expansion chamber 21 provided separately from the surge tank 13 via a communication passage 22. The intake expansion chamber 21 is closed to outside air and communicates only with the auxiliary intake port 9 via a communication passage 22.

Further, a shutter valve 23 is installed in the communication passage 22 to open and close the communication passage 22 depending on the operating state.

This shutter valve 23 is controlled by a control unit 26 that receives signals from an engine rotation speed sensor 24 and a throttle opening sensor 25 via driving means such as a three-way solenoid valve 27 and a negative pressure responsive actuator 28. The communication passage 22 is closed in a low rotation speed range where dynamic effects due to pressure fluctuations in the passage 22 cannot be obtained or in a low load range where dynamic effects are not required.

FIG. 3 shows the opening area of the intake port 6 by the intake valve 5 (line A) and the opening area of the auxiliary intake port 9 by the auxiliary intake valve 1o (line B).

As shown in this figure, the opening timing 10 and closing timing 1c of the intake port 6 by the intake valve 5 are set in the same way as before, that is, it starts opening a little before the bottom dead center DC and reaches the bottom dead center BD.
Closed a little later than C.

On the other hand, the opening timing 10' of the auxiliary intake port 9 by the auxiliary intake valve 10 is set to be earlier than the opening timing IO of the intake port 6 by the intake valve 5.

-〇- Note that the passage length of the communication passage 22 is set so that the pressure waves in the communication passage 22 resonate at a specific engine rotation speed that is characterized by improved output. In order to do this, the natural frequency of the air column in the communication passage 22 is set to be an integral multiple (for example, twice or four times) of the number of intakes per cylinder of the engine per unit time at the specified engine speed. The length of the communication path 22 may be set in advance.

The operation of such an intake device will be explained with reference to FIGS. 4 and 5.

Figure 4 shows the pressure fluctuations around intake port 6, inside the cylinder, and around auxiliary intake bow 1 to 9 during the intake stroke at a specific engine speed, when the opening timing of auxiliary intake port 9 is earlier than that of intake port 6 ( Lines C, D.

E) When both lines are opened at the same time (line Co
, Do, Eo). Also, Figure 5 shows the intake pressure wave (line F) near the intake bow 1-6
and pressure waves (line G) near the auxiliary intake port 9 are schematically shown over several cycles.

J shown in these figures: In the cylinder during the intake stroke, a pressure fluctuation occurs in which the negative pressure reaches its maximum at a predetermined time in the middle of the intake stroke when the rate of change in volume is large, and in response to this, the intake air is increased near the intake port 6. Pressure oscillations occur, and pressure oscillations also occur within the communication path 22 due to pressure propagation between the air WJ2 and the intake expansion chamber 21. This pressure vibration acts on the auxiliary intake port 9, and also influences the pressure fluctuation within the cylinder and the intake pressure vibration near the intake port 6, giving a vJ effect. In particular, when resonance occurs within the communicating passage 22, for example, as shown in FIG. 5, the period T of the natural vibration of the air column within the communicating passage 22 becomes the suction period T-.

The dynamic effect is enhanced when the natural frequency is 1/4 of the number of inhalations (4 times the number of inhalations).

In other words, when large pressure vibrations occur in the communication passage 22 due to resonance, the negative pressure in the cylinder a; (See Figure 4). Therefore, the intake pressure at the end of the intake stroke is increased and the amount of intake air supplied from the intake port 6 is increased, and the intake air stored in the intake expansion chamber 21 is also pushed from the auxiliary intake port 9 into the combustion chamber 4.
These effects enhance filling efficiency.

In particular, if the opening timing IO' of the auxiliary intake port 9 is set earlier than the opening timing 10 of the intake port 6, pressure waves in the communication passage 22 near the auxiliary intake port 9 (the fourth
Line E) in the figure is further strengthened than when the auxiliary intake bow 1-9 is opened at the same time as the intake port 6 (line Eo). In other words, by advancing the opening timing 10' of the auxiliary intake port 9, the pressure wave near the auxiliary intake port 9 increases due to the influence of the residual exhaust pressure in the cylinder immediately after the auxiliary intake port interval Io'. (E+ part), the oscillation increases the maximum negative pressure in the middle of the intake stroke (E2 part), and the oscillation also increases the pressure at the end of the intake stroke (F3).
part). In this way, the amplitude of the pressure wave near the auxiliary intake port 9 increases, and along with this, the pressure fluctuation inside the cylinder (
Line D) and the intake pressure wave near the intake port 6 (line C) are also strengthened compared to when the auxiliary intake port 9 is opened at the same time as the intake port 6 (line Do and line Co).
〇-ru. Therefore, the dynamic effect will be further enhanced.

Note that the auxiliary intake port 9, communication passage 22, etc. that provide the above-mentioned dynamic effect are provided separately from the original intake system for supplying intake air, so the original intake system may be compared depending on the layout etc. You can set the rules as you like. Furthermore, even if the intake passage 11 is in the original intake system, if the length of the intake passage 11 is set so as to enhance the dynamic effect at the specified engine speed, this and the resonance effect in the communication passage 22 can synergize. dynamic effect is enhanced.

FIG. 6 shows a second embodiment of the invention, in which:
The substantial passage length of the intake passage 11 for each cylinder from the surge tank 13 to the intake port 6 is made variable. That is, the intake passage 11 is formed with a relatively long passage part 11a and a short passage part 11b which are bifurcated into two at the upstream side and connected to the surge tank 13, respectively. Shatta valve 30 for changing intake passage length
is provided. 31 opens the shirt valve 30 -1
0=Negative pressure responsive actuator that operates to close; 32 is a three-way solenoid valve that receives a signal from the control unit 26 and controls the supply of negative pressure to the actuator 31; Further, the structure of the auxiliary intake port 9, the communication passage 22, the intake expansion chamber 21, etc., the setting of the opening timing of the auxiliary intake port 9, etc. are the same as in the first embodiment.

Then, the control unit 26 controls the shatter valve 23 of the communication passage 22 and the shatter valve 30 for changing the length of the intake passage, respectively, depending on the operating state, for example,
While the shatter valve 23 of the communication passage 22 is opened in an appropriate operating range other than the low rotation range or low load range, the intake passage length changing shatter valve 30 is opened in a relatively high-load operating range at a rotation speed higher than a predetermined rotation speed. It is scheduled to be held at

According to the stomach filling of the second embodiment, on the side of the intake passage 11 that supplies intake air, the above-mentioned shutter valve 30 is closed in the low rotation range, and the length of the intake passage is substantially lengthened, and in the high rotation range, the above-mentioned intake passage length is substantially lengthened. Since the intake passage length is substantially shortened by operating the shatter valve 30, the dynamic effect of the pressure vibration itself in the intake passage is enhanced on both the low rotation side and the high rotation side.

In this case as well, apart from the ``-2 intake passage 11, a dynamic effect can also be obtained by the communication passage 22 between the auxiliary intake port 9 and the intake engineering chamber 21, and in particular, the opening timing of the auxiliary intake port 9 can be controlled. By opening the intake port 6 earlier than the opening timing, the dynamic effect is enhanced due to the influence of the residual exhaust pressure.

FIG. 7 shows a third embodiment of the invention, in which:
Communication path 2 between the auxiliary intake bow 1-9 and the intake expansion chamber 21
A rotary timing valve 34 that opens and closes in synchronization with the engine is provided in the engine 2, and the actual opening timing of the auxiliary intake port 9 is adjusted by this timing valve 34. That is, when the auxiliary intake valve 10 is opened 1
11 is set early enough so that the timing valve 34 is opened after the auxiliary intake valve 10 is opened, so that the opening timing of the timing valve 34 becomes the actual opening timing of the auxiliary intake valve 1-0. The opening/closing timing of the timing valve 34 can be adjusted from -12 to -12 by a phase adjusting means (not shown). As shown in FIG. 8, the actual opening timing [0' of the auxiliary intake bow 1-9 by the timing valve 34 is advanced from the opening time IIIO of the intake port 6, but on the low engine speed side. The timing valve 34 is controlled to make the advance angle small and to increase the advance angle on the high rotation side.

According to this embodiment, on the low rotation side, the advance angle is made small, thereby suppressing the suction of exhaust gas into the communication passage 22, and on the high rotation side, the advance angle is made large, thereby reducing the residual exhaust pressure. 1 is sufficiently applied to the pressure within the communication path 22.

FIG. 9 shows a fourth embodiment of the invention. In this example,
In a two-cylinder rotary rev engine, pressure waves are propagated between the cylinders. That is,
A rotor housing 41 of each cylinder is equipped with a substantially triangular rotor 42 that rotates planetarily, and this rotor 42 defines three chambers 43 corresponding to combustion chambers.

Further, in addition to the intake port 45 that supplies intake air, an auxiliary intake port 46 is formed in the side housing 44 of each cylinder, and these ports 1 to 45 and 46 are opened and closed as the rotor 42 rotates. It has become.

Intake passages 48 connected to the intake ports 45 of each cylinder merge downstream of the surge tank 47, and the merged portion communicates with the surge tank 47. In addition, the auxiliary intake port 46
is communicated with the auxiliary intake port 46 of the other cylinder via a communication passage 49, and this communication passage 49 does not directly communicate with the intake passage 48, but communicates only the auxiliary intake ports 46 of both cylinders with each other. There is. Other parts equivalent to those of the first embodiment will be omitted with the same numerals as ``t'' and their explanations will be omitted.

FIG. 10 shows the opening area of the intake port 45 (line 1'') and the opening area of the auxiliary intake port 46 (line I) in this embodiment. With the rotation of
The port shape is set so that it can be opened earlier than [110].

According to this embodiment, if the length of the communication passage 49 is set so that the pressure wave propagation time between the cylinders through the communication passage 49 corresponds to the operating interval of both cylinders at a specific engine speed, the specified The dynamic effect is increased at engine speed.

That is, as shown in FIG. 11, an intake pressure wave shown by line J is generated near the intake port 45 as the intake port 45 opens and closes, while an intake pressure wave shown by line J is generated near the auxiliary intake port 46 as the auxiliary intake port 46 opens and closes. A pressure wave is generated as shown by the line. A dynamic effect is obtained by propagating this pressure wave between the two cylinders through the communication passage 49. In particular, when the pressure wave is propagated with a time corresponding to the operating interval of both cylinders, resonance occurs. As a result, the pressure fluctuation in the communication v849 becomes large, and the intake pressure wave is also strengthened due to its influence. Also in this case, by setting the opening timing 10' of the auxiliary intake port 46 earlier than the opening timing IO of the intake bows 1 to 45, the pressure waves near the auxiliary intake port 46 and the intake pressure waves are reduced due to the influence of the residual exhaust pressure. This will further enhance the dynamic effect.

In addition to these embodiments, in a reciprocating engine, the auxiliary intake ports of each cylinder are connected through a communication passage, or in a rotary piston engine, the auxiliary intake port and the intake expansion chamber, which is closed from the outside air, are connected through a communication passage. It may be possible to communicate.

(Effects of the Invention) As described above, the present invention provides an auxiliary intake port and an auxiliary intake port that is connected to the auxiliary intake port of another cylinder or is closed from the outside air, in addition to the intake port for supplying intake air and the intake system connected thereto. A communication passage is provided that communicates with the intake expansion chamber, and the dynamic effect is enhanced by the pressure vibrations generated within this communication passage, so the M4 of the original intake system for supplying intake air is
The structure can be simplified, or the dynamic effect can be enhanced synergistically with the original intake system and the passage. That'-
In particular, the opening timing of the auxiliary intake port is made earlier than the opening timing of the intake port, and the residual exhaust pressure in the cylinder before the intake port 1 to 1 interval is effectively used to increase the pressure in the communication passage. Since the fluctuation is strengthened, the dynamic effect of the auxiliary intake port and the communication passage can be further enhanced, and the filling efficiency can be improved by -1.

[Brief explanation of the drawing]

Fig. 1 is a schematic plan view showing the first embodiment of the present invention, Fig. 2 is a side view of the same, Fig. 3 is a view showing the opening area of the intake port and auxiliary intake port, and Fig. 4 is a specific engine rotation speed. Fig. 8 is a diagram showing pressure fluctuations near the intake port, in the cylinder, and near the auxiliary intake port, a schematic side view, and Fig. 8 is a diagram showing the relationship between the auxiliary intake port actual interrogation timing and the engine rotation speed in the third embodiment. , FIG. 9 is a schematic side view showing the fourth embodiment, FIG. 10 is a diagram showing the opening area to the intake port and auxiliary intake port 1 in the fourth embodiment, and FIG. 11 is according to the fourth embodiment. It is a figure which shows the pressure fluctuation state in case. DESCRIPTION OF SYMBOLS 1...Engine body, 2...Cylinder, 4...Combustion chamber, 5゜45...Intake ball l~, 9.46...Auxiliary intake port, 21...Intake expansion chamber, 22 .49...Communication path. = 17- Figure 1 Figure 7 Figure 8

Claims (1)

[Claims] 1. In addition to the intake port that supplies intake air to the combustion chamber, there is also an auxiliary intake port that is opened during the intake stroke, and an intake expansion that communicates only with the auxiliary intake ports of other cylinders or is closed from the outside air. What is claimed is: 1. An intake system for an engine, comprising: a communication path communicating with a chamber; and an opening timing of the auxiliary intake port is set earlier than an opening timing of the intake port.