JPS6255416A - Suction system for engine - Google Patents

Abstract

PURPOSE:To enhance the air intake efficiency and to improve the acceleration or deceleration responding performance by installing a throttle valve in a suction pipe, through which a pressure wave propagates, and increasing the opening angle of the throttle valve when the 'accel-position' is on an opening position which is sufficient enough for the maximum amount of intake-air that the engine can takes in for a given engine speed to pass through the suction pipe. CONSTITUTION:Cylinder groups 1a to 1c and 1d to 1f are connected to independent intake air passage 4a and 4b via manifolds 2a and 2b, respectively. The intake air passages 4a and 4b are connected to each other by means of a connecting passage 7 with a closing valve 8, which is situated in the middle of the passages 4a and 4b. When the engine is running at a high speed, the closing valve 8 is opened so that the pressure wave of the intake air suitable for high speed operation is generated. Throttle valves 9a and 9b are provided downstream with respect to the connecting passage 7 and are opened or closed by a motor 10, according to the 'accel-pedal position.' When the 'accel-pedal position' is on a valve opening position which is sufficient enough for the maximum amount of intake air that the engine can take in for a given engine speed 13 to pass through the intake air passages 4a and 4b, the throttle valves 9a and 9b are opened further, exceeding the normal position.

Description

DETAILED DESCRIPTION OF THE INVENTION (Industrial Application Field) The present invention relates to an engine intake system that performs supercharging by the dynamic effect of intake air, that is, by pressure waves propagating in the intake passage. .

(Conventional technology and its problems) Conventionally, in automobile engines, etc., pressure waves generated in the intake passage due to the suction action of the piston, etc. are used to perform supercharging in a specific rotation range of the engine to improve output. Various air intake devices are known.

For example, in the engine intake system disclosed in Japanese Utility Model Application Publication No. 59-148425, the cylinders are divided into two groups of cylinders in which the intake l:jfi orders are not adjacent to each other, and the intake passages of the multiple cylinder groups are It is formed to a predetermined length upstream of the passage merging portion and then merged into the common intake passage.

In this intake system, the frequency of pressure waves generated in the intake passages of each cylinder group and whose phases are shifted by half a wavelength from each other is determined by the intake passages of each cylinder group and the intake passages up to the flow-side confluence. The engine's output is improved by the resonance of the intake air that occurs when the natural frequency matches the natural vibration frequency.

Here, the confluence of the intake passages of two cylinder groups creates a positive pressure by inverting the negative pressure wave that propagates upstream from the intake passage of each cylinder group by the positive pressure wave from the other cylinder group. It functions as a pressure reversal unit that converts pressure waves into waves and transmits them downstream.

In this prior art, a throttle valve is provided in the pressure propagation passage downstream of the pressure reversal part, and when the opening degree of the throttle valve is not sufficient, the pressure wave propagating in the intake passage is attenuated.
There is a problem in that the supercharging effect due to the pressure waves is not sufficiently exerted.

In other words, when the engine is running at low speeds, the same amount of air is supplied as when the throttle valve is fully open, that is, the amount of air that the engine can take in at that speed, even if the throttle valve is not fully opened. There are cases where the accelerator pedal is not depressed, and the accelerator pedal is depressed only to the accelerator position corresponding to the throttle valve opening sufficient to supply the above-mentioned intakeable air amount to the engine.

To solve this problem, a throttle valve is provided in a portion other than the intake passage used for pressure propagation. In the case of the above intake system,
26120, if a throttle valve is provided in the intake passage upstream of the pressure reversal section.

solve.

However, for an engine that performs supercharging by the dynamic effect of intake air as described above even when the engine rotates at low speeds, it is necessary to lengthen the pressure propagation passage.

Therefore, if the throttle valve is provided in an intake passage upstream other than the pressure propagation passage, the volume of the intake passage downstream of the throttle valve becomes large, causing a problem that the responsiveness of acceleration and deceleration deteriorates.

The present invention has been made in view of the above, and an object of the present invention is to provide an intake system for an engine that fully exhibits the dynamic effect of intake air at least at low rotation speeds without impairing the responsiveness of acceleration. This is the purpose.

(Means for Solving the Problems 1 Effect) In order to achieve the object described above, the present invention provides an engine that performs supercharging in a specific rotation range by pressure waves propagating in the intake passage. A throttle valve that controls the intake amount of the engine by its opening degree is provided inside the engine, and an accelerator linkage device that changes the opening degree of the throttle valve in accordance with the accelerator position, and an accelerator linkage device that changes the opening degree of the throttle valve in accordance with the accelerator position. and an opening correction device that increases the opening of the throttle valve to a degree corresponding to the accelerator position or more when the opening is sufficient to pass the intake air amount of the engine at the engine rotational speed. It is characterized by

With the configuration described above, by providing the throttle valve in the pressure propagation passage, it is possible to reduce the volume of the intake passage downstream of the throttle valve, thereby improving the responsiveness of acceleration and deceleration.

In addition, by increasing the opening of the throttle valve using the opening correction device, the attenuation of pressure waves by the throttle valve can be reduced, and the dynamic effect of intake air can be fully exerted even at low speeds.

Furthermore, the above-mentioned opening degree correction device increases the opening degree when the throttle valve opening degree becomes sufficient to pass the amount of intake air at the engine rotational speed at that time. This has the advantage that the amount of intake air does not increase against the driver's will.

(Example) Embodiments of the present invention will be described below with reference to the drawings.

FIG. 1 shows an example in which the present invention is implemented with a six-cylinder engine.

Cylinder groups 1a-If are %1 a-1d-1b-1f-1c
- Intake and ignition are performed in the order of 1e, and two cylinder groups 1a whose intake orders are not adjacent to each other.
The intake passage is divided into '=I C+ 1 d-1f.

The intake passage for each cylinder group is composed of two surge tanks 2a+2b, an independent intake passage 3 for each cylinder branched from the surge tanks 2a and 2b, and a resonance passage 4a+4b upstream of the surge tanks 2a and 2b.

Each of the resonance passages 4a+4b joins at the downstream end 6a of a common passage 6 provided with an air cleaner 5, so that supercharging is performed by the dynamic effect of intake air when the engine is running at a relatively low speed.
It's long enough.

A communication path 7 is provided in the middle of the resonance path 4a t 4b to communicate between the resonance paths 4a and 4b, and a resonance switching valve 8 is provided in the communication path 7.

When the engine is running at low speed, the resonance switching valve 8 is closed.
A is made to function as a pressure reversal part, so that the pressure wave of positive pressure and negative pressure generated by the suction action of the piston and stored in the surge tank 2at2b is reversed at 63 and transmitted to the surge tank.

At medium speeds, the resonance switching valve 8 is opened and the communication passage 7 functions as a pressure reversal section, and the dynamic effect of the intake air is used to perform supercharging in the same way as at low speeds, and each cylinder is independently operated at high speeds. The intake passage 3 is used as a pressure propagation passage, and the surge tank 2at2b
The length of each intake passage is adjusted so that it acts as a pressure reversal section.

The throttle valves 9at9b are each provided downstream of the communication passage 7 in the resonance passages 4a+4b, and control the intake air amount of the engine depending on the opening degree of the throttle valves 9a+9b, thereby controlling the output of the engine. In order to further reduce the volume of the intake passage downstream of the throttle valve and improve responsiveness to acceleration and deceleration, a throttle valve may be provided in the intake passage for each cylinder.

1 The opening degree of the aperture squares 9a+9b is adjusted by the control unit 11 via the motor 10.

The control unit 11 receives an accelerator sensor 12, determines an appropriate opening degree of the throttle valve based on the signal, and operates the motor 10.

FIG. 2 is a flowchart of the process carried out in this control unit.

Here, there is not enough air to pass through, which is determined by the engine speed.

Find the accelerator position 〇A corresponding to the minimum opening degree of the valve,
The motor is designed to compare the actual accelerator positions θ and θA, and when θ is smaller, set the throttle valves 6a+6b to the opening corresponding to the above-mentioned accelerator position θ, and otherwise open the throttle valves 9a+9b fully. Move 10.

That is, the throttle valves qa and 9b are normally controlled to have an opening degree corresponding to the accelerator position θ, as shown in FIG. 3(a). However, if the accelerator position 0 is the minimum opening of the throttle valve sufficient to pass the intake air amount determined by the engine rotational speed N, and the corresponding accelerator position f & IffA (Fig. 3 (b)), When also large, the throttle valves qa and 9b are fully opened.

However, a method other than this can also be used to detect when the throttle valve should be opened to an opening degree greater than the opening degree corresponding to the above-mentioned accelerator position θ.

Figure 4 shows the method of moving the throttle valve and the above accelerator position θ.
2 is a partial diagram of an example in which a method for detecting when to open a throttle valve based on an opening corresponding to an opening is implemented using a method different from that of the motor 10 and control unit 11 shown in FIG. 1. FIG.

When the accelerator is pressed, the wire 14 is pulled against the force of the spring 15, the lever 16 moves, and the throttle valve lever 17 in contact with the lever 16 moves against the force of the spring 18, and the I
The iris valves 9a+9b are opened.

Here, if the throttle valve opening corresponding to the accelerator position e is sufficient to allow the intake air amount of the engine to pass through, the pressure downstream of the throttle valve 9a becomes high, so this pressure is set in advance. When the pressure is higher than the set pressure, the following opening adjustment device will operate.

First, the three-way valve 20 connects the negative pressure tank 21 and the diaphragm device 22 at the end of the diaphragm device 19 .

In the negative pressure tank 2, a check valve 23 stores a large negative pressure equivalent to the flow of the throttle valve 9a during low-load operation.Using this negative pressure, the diaphragm device 22 The throttle valve lever 17 is moved so that the valves 9a+9b are opened wide according to the opening degree opened by the lever 16.

When the accelerator is released, the return lever 24 integrally formed with the lever 16 returns the throttle lever 17 by the force of the spring 15, reducing the opening degree of the throttle valves 9a + 9b and opening the throttle valves 9a.
By lowering the downstream pressure and returning the three-way valve 20 to its original state, the negative pressure in the diaphragm device 22 is gradually released to the atmosphere through the three-way valve 20 and the restrictor 25 provided at its atmosphere opening, and the force of the spring 18 is increased. The throttle valve lever 17 returns to the lever 16.
come into contact with.

In this example, the mechanism for detecting when the throttle valve should be wide open is simpler than in the example using electric control described above, but the delicate control of the throttle valve is not as easy as in the example described earlier. is better.

The above description focuses on an example of application to a 6-cylinder engine shown in FIG. 1. However, the present invention is also effective for engines other than 6-cylinder engines.

FIG. 5 shows an example in which the present invention is implemented with a four-cylinder engine.
The intake passages of the cylinder groups 101a to 101d are composed of one surge tank 102, an independent intake JO passage 103 for each cylinder branched from the surge tank 102, and a resonance passage 104 upstream of the →r-jitank 102. cleaner 105
The 0F flow is provided with a container 106 that functions as a pressure reversal section.

The length of the resonance passage 104 is set so that pressure waves are transmitted between the surge tank 102 and the container IQG, and the dynamic effect of intake air is exhibited at relatively low rotation speeds.

The throttle valve 109 is connected to the surge tank 1, which is used as a pressure propagation passage for exerting the dynamic effect of intake air at low rotation speeds.
02 and the container 106 in the resonant passage 104.
Yes, it controls the amount of air intake into the engine.

The following embodiments are all provided with a pressure reversal section.

However, the present invention is not limited to engines having a pressure reversal section.

In addition, the dynamic effect of intake air depends on the length of the intake passage, etc.
Since the supercharging effect due to the dynamic effect of intake air is not exerted except around a specific rotational speed, the calibration valve opening correction device may not be operated outside of the vicinity of the specific rotational speed.

(Effects of the Invention) As explained above, according to the present invention, by providing a throttle valve in the pressure propagation passage, it is possible to reduce the intake passage downstream of the throttle valve, thereby improving the responsiveness of acceleration and deceleration. can.

Further, by increasing the opening degree of the throttle valve using the opening degree correction device, it is possible to reduce the attenuation of pressure waves by the throttle valve, and to fully exhibit the dynamic effect of intake air.

Furthermore, the above-mentioned opening degree correction device increases the opening degree when the throttle valve opening degree becomes sufficient to pass the amount of intake air at the engine rotational speed at that time. This has the effect that the amount of intake air does not increase against the driver's will.

[Brief explanation of the drawing]

Fig. 1 is an overall view of the first embodiment of the present invention, Fig. 2 is a flowchart showing the operation of the main parts of the above embodiment, and Fig. 3 (al is a graph fbl showing the relationship between the accelerator position and the throttle valve opening). is a graph showing the relationship between set accelerator position #A and rotational speed 51jN, FIG. 4 is an enlarged view of the main parts of the second embodiment, and FIG. 5 is an overall view of the third embodiment. 2a+2b...・・・・・・・・・・・・・・・Surge tank, 3・・・・・・・・・・・・・・・Independent intake passage,
4a + 4b・・・・・・・・・・・・Resonance passage, 9at9b・・・・・・・ Throttle valve, 10
......Motor, 11...
・・・・・・・・・・・・Control unit, 12・
・・・・・・・・・・・・Accelerator sensor. 13・・・・・・・・・・・・Rotation speed sensor,
16・・・・・・・・・・・・・Lever, 17・・・・・・
・・・・・・・・・・ Throttle valve lever, 22・・・・・・・
・・・・・・・・・Diaphragm installation ff! , 1o2・
・・・・・・・・・・・・・・・Surge tank, 103・
......Independent intake passage, 104...
・・・・・・Resonance passage, 109・・・・・・・・・
Throttle valve Fig. 1 Fig. 3

Claims (1)

[Claims] In an engine that performs supercharging by pressure waves propagating in an intake passage, a throttle valve is provided in the pressure wave propagation passage of the intake passage and controls the intake air amount of the engine by the opening degree of the throttle valve; An accelerator linkage device that changes the opening degree of the throttle valve in accordance with the accelerator position, and the throttle valve opening degree corresponding to the accelerator position is sufficient to pass the amount of air that can be taken in by the engine at the engine rotational speed at that time. 1. An intake system for an engine, comprising: an opening correction device that increases the opening of the throttle valve to be greater than the opening corresponding to the accelerator position when the opening is at the accelerator position.