JPH0654090B2 - Engine intake system - Google Patents

Description

TECHNICAL FIELD The present invention relates to an intake system for an engine having a plurality of intake ports with different closing times.

(Prior Art) In an engine, there is an intake system that employs an inertial supercharger provided with a vibrator so as to change the pressure vibration frequency of the air in the resonance chamber in response to the operating state of the engine. . This method is used, for example, in Japanese Utility Model Laid-Open No. 58-1.
It is disclosed in Japanese Patent No. 4425.

In this case, the inertial supercharger has a low engine load,
Conversely speaking, the pressure wave is generated in the high load operation region to improve the intake charging efficiency.

On the other hand, an intake system for an engine is generally provided with one intake passage for each cylinder, but in recent years, two parallel intake passages are provided for each cylinder for the purpose of improving filling efficiency and mixing. One of them is provided on the P (primary) side and the other is on the S (secondary) side, and for example, an S-side intake valve is closed at a timing later than the P-side intake valve.

As described above, when the above-described vibrator is provided in an engine having two intake ports with different closing timings, it is assumed that P
If it is provided on the side, since the S side is opened when the P side is vibrated, the pressure wave due to the vibration escapes from the S side, and as a result, the pressurizing effect cannot be effectively obtained in the combustion chamber. .

(Object of the Invention) The present invention has been made in view of the above problems,
The purpose of the present invention is to enhance the intake air charging efficiency without complicating the structure.

(Structure of the Invention) In order to achieve the above object, according to the present invention, there is provided an intake system for an engine having a plurality of intake ports having different closing times for one cylinder. The exciter is provided only in the passage communicating with the intake port with the slower intake port, and the exciter has a positive peak value of the pressure wave generated by the exciter, and the closing time of the intake ports is earlier than the other. After the closing of the intake port, before the closing of the intake port whose closing timing is late among the plurality of intake ports, it is set so as to come to the intake port whose closing timing is late.

With the above-described configuration, the pressure wave generated by the vibration exciter is prevented from leaking out from the intake ports other than the intake port whose closing timing is late. Therefore, it is possible to more effectively increase the intake air charging efficiency without complicating the structure.

Embodiment An embodiment of the present invention will be described below with reference to the drawings.

FIG. 1 relates to the first embodiment, 1 is a cylinder, and a crankcase 2 is provided in the lower part thereof. The cylinder 1 is provided with a piston 3, and the crankcase 2 is provided with a crankshaft 4. On the other hand, in the upper part of the cylinder 1, a combustion chamber 5 is formed, and an exhaust passage 8 having an exhaust valve 7 for opening and closing an exhaust port 6 is connected.

On the other hand, the intake passage has the first intake passage 9 as the first stage,
The following second intake passage 10 is provided.

The first intake passage 9 is provided with an air cleaner 12 and an air flow meter 13 arranged near the downstream side thereof.

On the other hand, the second intake passage 10 is a parallel type of the P-side intake passage 10P and the S-side intake passage 10S. The P-side intake port 14P and the P-side intake port 14P are provided in the P-side and S-side intake passages 10P and 10S, respectively. A valve 15P and an S-side intake valve 15S are provided at the S-side intake port 14S so as to be openable and closable.

A surge tank 16 is provided between each of the P-side and S-side intake passages 10P and 10S and the first intake passage 9, and the surge tank 16 has a portion from the first intake passage 9 to the P-side.
It is partitioned by a branch passage wall 17 so as to be branched into the intake passages 10P and 10S on both sides. This branch passage wall 17
P-side and S-side throttle valves 18P and 18S are provided at the upstream end of the.

One of the P-side intake passage 10P and the S-side intake passage 10S, that is, the upstream side of the P-side intake passage 10P, the injector 19 is installed, and in particular, the surge tank 16 upstream of the S-side intake passage 10S. The shaker 20 is provided at a position corresponding to, and the S-side intake valve 15S on which the shaker 20 is installed is the P-side intake valve 15
It is a side that opens later and closes later than P, and is characterized in that the vibrator 20 is arranged in the intake passage 10S on the S side that closes later. The relationship is shown as corresponding symbols P and S in FIG.

In this case, the vibrator 20 has a solenoid 22 inside a vibrator body 21, and a vibrating plate 23 that reciprocally vibrates by the solenoid 22 is attached to the back surface of a vibrating diaphragm 24. ing.

On the other hand, reference numeral 25 is a control circuit, and an intake air flow rate signal 26 for inputting an intake air flow rate by the air flow meter 13 and an intake air temperature sensor 27
The intake air temperature signal 28, which is input as the intake air temperature, is input as the intake air temperature signal 28, and the throttle valve 18P and 18S are respectively input as a slot opening signal 30 which is input through a slot opening sensor 29. A crank angle signal 32 is input by 31.

In response to such an input, the control circuit 25 outputs a fuel control signal 33 to the injector 19 and an exciter actuation signal 34 to the exciter 20, respectively.

Here, the intake air flow rate signal 26 is input only for fuel control, and the intake air temperature signal 28, the throttle opening signal 30, and the crank angle signal 32 are also used for the fuel control.

On the other hand, the crank angle signal 32 is for calculating the engine speed as well as the crank angle for setting the vibration timing, and the intake air temperature signal 28 is for calculating the pressure propagation time of the vibration exciter 20 described later. Is entered as.

Here, the crank angle signal 32 is, for example,
It is transmitted from the crank angle sensor 31 facing the pulsar provided on the outer periphery of the flywheel (not shown) of the engine,
As a result, the crank angle signal 32 input to the control circuit 25 is supplied to a phase and rotation speed detection circuit (not shown) and is used for setting an excitation timing described later.

In this case, a signal from the distributor or the like may be used.

Next, based on the flow chart shown in FIG.
The control of the shaker 20 in the figure will be described.

At step P1, the operating state of the engine is detected.

In this case, the engine speed is calculated from the throttle opening signal from the throttle opening signal 30 in FIG. 1 and the crank angle signal 3 from the crank angle sensor 31.

Next, at step P2, it is judged from the above whether or not it is the rotational speed zone in which the vibrator 20 is operated. In this case, the rotation speed zone for operating the vibration exciter 20 is the fourth
It is shown as an example in the figure. That is, FIG. 4 is a rotational torque curve with respect to the engine speed, where:
Z1 and Z2 are the vibration exciter operating zones. The vibrator exciter operating zone is located in the middle (medium speed) specific region Zi where the rotational torque temporarily decreases and in the vicinity of the throttle opening being fully opened. It is set as a region Z2.

Here, when the engine is in the vibration exciter operating zone Z1 or Z2 (YES), the process returns to step P3, and when not (NO), the process returns.

In step P3, the intake air temperature t and the intake air flow rate Q are read into the control circuit 25, and in the next step P4, the pressure propagation time is calculated.

When the pressure propagation time is calculated, the next step P5
Detects θ. This θ is a value that indicates at what timing the vibration exciter 20 should be activated on the crank angle. That is, as shown in FIG. 5, the pressure propagation time is Δθ on the crank angle, and the pressure wave is If the timing of the end of propagation is θo on the crank angle, θ = θo-
The relationship is Δθ.

Here, if the suitable value of θo is set so that the peak of the propagated pressure wave falls within the range of 50 degrees before the intake port closing start point IC on the crank angle, the mixed gas once sucked flows backward. The pressure can be effectively increased without

From this, when θ is calculated, the actual crank angle is read in step P6, and it is determined in step P7 whether or not the timing angle θ has been reached.

When the set timing angle θ is reached in this way, step P8
At, the shaker 20 is activated.

Therefore, in the above configuration, only the P-side intake port 14P is opened at the time of low load, and the S-side intake port 14S is opened / closed in addition to the P-side intake port 14P at the time of high-load operation. Since the shaker 20 is installed on the side of the intake ports 14P, 14S that corresponds to the high-load S-side intake port 14S, pressure is passed through the S-side intake port 14S after the P-side intake port 14P has already closed. The pressure wave does not escape from the P-side intake port 14P as a result of the action of the wave, and therefore the filling efficiency can be effectively increased.

Further, when the load is low, the mixed gas is sucked only through the P-side intake port 14P, but since the S-side intake port 14S is closed, the sucked gas is passed through the S-side intake port 14S to the vibrator 20. The mixed gas does not blow back, and in this case, since the S-side throttle valve 18S is closed, there is no possibility that the vibrating diaphragm 24 of the shaker 20 is contaminated by the mixed gas.

In particular, if the timing at which the pressure wave due to vibration acts through the S-side intake port 14S is set immediately before the intake valve closing start point as in the above-described embodiment, the pressure in the combustion chamber 5 may increase. At a certain timing, a higher pressure wave acts on the compressed gas in the combustion chamber 5 through the S-side intake passage 10S, so that the pressure is effectively increased through the S-side intake port 14S, and the intake air flows backward. There is an advantage that it is introduced in large quantities.

Next, a second embodiment shown in FIG. 6 will be described.

The second embodiment shows an engine having a so-called partial supercharging type intake device, that is, supercharging is not performed by the supercharger 35 with respect to the total amount of air taken in, and it corresponds to high load operation. Then, by adding supercharging only in the S-side intake passage 10S, the necessary and sufficient supercharging effect can be obtained with the small-sized supercharger 35.

For such a so-called partially supercharged engine,
The present invention can be applied as follows.

That is, the vibration exciter 20 is provided in the surge tank 16 provided in the S-side intake passage 10S having the supercharger 35.

With this configuration, during high load operation, the intake air from the supercharger 35 is introduced into the S-side intake port 14S through the intercooler 36, whereby the intake air pressure level is generally increased, Since the vibration is applied at the same timing as in the first embodiment, the peak point of the intake pressure can be increased more effectively. Here, 37 in FIG. 6 is a transmission pulley,
38 is an electromagnetic clutch, 39 is a potentiometer, and 40 is a bypass passage having a relief valve 41.

Further, in the above-described embodiment, when the vibration diaphragm 24 is vibrated via the vibration plate 23 as shown in FIG. 1, a pressure difference due to a negative pressure is generated before and after the vibration diaphragm 24, especially at a light load. Although easy, here, the surge tank 16 and the inside of the vibration exciter 20 are made to communicate with each other by the pressure balancing communication passage 42, thereby reducing the above-mentioned pressure difference, thereby improving the durability of the vibration exciter 20. Is done.
The present invention can also be applied to a rotary engine.

(Effects of the Invention) As described above, the present invention can effectively increase the charging efficiency of intake air without complicating the structure.

[Brief description of drawings]

FIG. 1 is a system diagram of an engine intake system showing a first embodiment of the present invention, FIG. 2 is a valve opening curve diagram showing opening and closing timings of intake valves on the P side and S side, and FIG. Fig. 4 shows the engine torque curve showing the exciter operating zone, Fig. 5 (I) is the pulse current waveform diagram applied to the exciter, and Fig. 5 (II) is the intake air. The valve opening curve diagram and FIG. 6 are system diagrams showing the second embodiment. 14P, 14S ... intake port, 20 ... vibrator.

Front page continuation (72) Inventor Toshiki Okazaki 3-1, Shinchi, Fuchu-cho, Aki-gun, Hiroshima Mazda Co., Ltd. (56) Bibliographic references Sho 54-167208 (JP, U) JP 47-43365 (JP) , B1)

Claims (1)

[Claims] 1. An intake system for an engine having a plurality of intake ports having different closing times for one cylinder, wherein a shaker is provided only in a passage communicating with an intake port having a later closing time among the plurality of intake ports. And the positive peak value of the pressure wave generated by the shaker is after the closing of the intake port of the plurality of intake ports whose closing timing is early, An intake device for an engine, characterized in that it is set so as to come to an intake port with a late closing time before closing an intake port with a late closing time of the ports.