JPS6394023A - Intake-air control device for engine - Google Patents

Abstract

PURPOSE:To prevent the torque of an engine from lowering on the low speed side of a set rotational speed, by performing delay control for the timing of the initiation of air-intake in the set rotational speed range, and by releasing the delay control on the lower side of the set rotational range. CONSTITUTION:A throttle valve 17 is disposed in an auxiliary intake-air passage 9a downstream of a main intake-air pipe 13. Further, a cylindrical timing valve 18 is rotatably disposed in a downstream side of an intake-air passage 19 and is connected to a crank shaft 24 through the intermediary of a spark advance mechanism 22. The timing of initiation of air intake is delayed from the the to dead center of air intake in a set rotational speed range so as to increase the rate of charge. A bypass valve 20 is opened on the lower speed side of the set rotational speed range to release delay control by the timing valve 18. With this arrangement, it is possible to prevent the torque of an engine from lowering on the lower speed side.

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to an intake control device for an engine, and more particularly to a device for controlling an intake device that performs intake using pressure waves generated in an intake passage.

(Prior Art) Engines have been proposed that utilize dynamic effects of intake air, such as intake inertia and resonance effects, to increase charging efficiency and thereby ensure high output.

However, when attempting to improve filling efficiency by utilizing the effect of pressure waves of intake air, the following problems arise. In other words, when the engine speed decreases, the downward speed of the piston decreases, and therefore the generated negative pressure wave becomes smaller.
The effect of improving the filling rate also decreases. In addition, while the propagation of pressure waves occurs at a constant speed, the speed of sound, the desired timing for the pressure wave to push the intake air changes depending on the engine rotational speed. It is difficult to obtain the effect of improving filling efficiency by waves.

In view of these circumstances, Japanese Patent Application Laid-Open No. 55-107018 discloses an air supply reservoir provided in the intake passage upstream of the intake valve, and an air supply passage provided in communication between the cylinder and this intake air reservoir. , an air supply control valve having a valve plate that rotates at the same speed as the rotational speed of the crankshaft or one-half the rotational speed of the crankshaft, and the cylinder and the air supply reservoir are communicated with each other according to the rotational speed of the crankshaft by this control valve. An intake structure for an engine is disclosed in which the intake air structure of the engine is controlled so that the effect of increasing the filling rate due to the pressure waves of the intake air can be obtained in a wide range of revolution speeds.

(Problems to be Solved by the Invention) In general, the engine rotational speed (hereinafter referred to as the tuned rotational speed) at which the effect of increasing the filling rate due to the pressure waves generated in the intake system is obtained is expressed by the following functional expression.

θeν N=□ ・・・・・・・・・■ Nicode, N: Synchronized rotation speed (ROM), θe: Effective open period eg), C: Specificity of the intake system during the intake valve open period The frequency is (112).

The effective valve opening period does not mean the opening period of the intake system, but is the period during which intake air is actually introduced into the cylinder.In the structure disclosed in the above publication, the opening and closing period of the intake air control valve is , is included within the valve opening period of the intake valve, so the effective valve opening period is when the intake air control valve is open.

In the device of this publication, the intake valve is fff! During this period, the valve opening timing is changed according to the engine speed, and by controlling the valve opening timing according to the engine speed, it is possible to shift the timing of the generation of negative pressure waves. Therefore, the effect of increasing the filling rate due to pressure waves can be obtained in a certain range of engine speed ranges.

That is, in this 5A setting, by changing θe in the above equation 0, the range in which the tuned rotation speed can be obtained is expanded according to the variable range.

However, the engine speed range in which such an effect can be obtained is limited, and the filling rate cannot be increased in the entire range.

Therefore, in areas where the opening timing of the control valve cannot be changed, the timing at which the pressure wave pushing effect can be obtained,
There was a problem in that there was a large deviation in the intake timing, and when an extreme deviation occurred, the engine torque was lower than if it were not controlled by a control valve.

In order to solve this problem, it is possible to make the timing of the control valve variable throughout the engine rotation range, but
The device becomes large and complicated, making it impractical.

This invention was made in view of these problems, and its purpose is to delay the actual intake start timing in a set rotation range and maintain the effect of increasing intake air filling due to pressure waves. It is an object of the present invention to provide an engine intake air control all device which can prevent a decrease in engine torque as much as possible at least on the low speed side of a set rotation range.

(Means for Solving the Problems) In order to achieve the above object, the present invention provides an engine intake control device which is provided on the upstream side of the intake port of the intake passage communicating with the combustion chamber of the engine. a timing valve that retards the intake timing from the intake top dead center of the combustion chamber; a canceling means for canceling the intake start timing delay caused by the timing valve; an engine rotation speed detection means for detecting the engine rotation speed; The intake start timing delay control by the timing valve is performed in a predetermined rotation range according to the output, and the release f operates the release means at least on the low speed side of the predetermined rotation range, and the control means is configured.

(Function) According to the engine intake control system configured as described above, the actual intake start timing is delayed by the timing valve in a predetermined rotation range, and the intake air is filled by pressure waves for 1 ton.
ltl can be increased, and at the low speed side of this rotation range, the delay in the intake start timing caused by the timing valve is canceled, so the state returns to a state where the intake start timing is not delayed, and at least the engine torque under normal operating conditions is reduced. Secured.

(Embodiments) Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the accompanying drawings.

1 to 3 show an embodiment of an engine intake system according to the present invention.

The intake system shown in the figure is one in which the present invention is applied to an in-line four-cylinder engine, in which four cylinder bores 3 are formed in the cylinder block 2 of the engine 1, and a piston 4 is reciprocated in each cylinder bore 3. It is arranged so that it can move freely.

A cylinder head 5 is connected above the cylinder block 2 , and a space formed by a space above the piston 4 in the cylinder bore 3 and a lower recessed portion of the cylinder head 5 constitutes a combustion chamber 6 . An intake port 7 and an exhaust port 8 are open in the combustion chamber 6, and an intake passage 9 and an exhaust passage 10 are formed in the cylinder head 5 so as to communicate with the intake port 7 and exhaust port 8. An intake valve 11 is associated with the intake port 7, and an exhaust valve 12 is associated with the exhaust port 8. In addition, the cylinder head 5
The spark plug 12a is arranged so that its tip protrudes into the combustion chamber 6. A manifold is connected to the intake passage 9 of each cylinder, and a fuel injection valve 12b is attached near this connection. 4th cylinder and 2nd cylinder. The third cylinder is merged with the auxiliary intake passages 9a and 9a separately on the upstream side, and this n1 intake passage 9
a and 9a merge again on the upstream side to form the main intake passage 13.
is formed.

An air cleaner 14 is installed at the upstream end of the main intake passage 13, and an air flow meter 15 for measuring the intake air flow area is installed downstream of the air cleaner 14.

Further, sub-intake passages 9a, 9a on the downstream side of the main intake passage 13
A cylindrical timing valve 18 is rotatably disposed in the intake passage 9 on the downstream side of the auxiliary intake passage 9a.

Further, a bypass passage 19 is provided downstream of the timing valve 18 in the intake passage 9, and a bypass valve 20 is installed at the connection portion between each intake passage 9 and the bypass passage 9. By opening the valves, the intake passages 9 are brought into communication with each other.

In the radial direction of the timing valve 18, an opening 21 is provided corresponding to each cylinder and communicates with the intake passage 9 of each cylinder at a predetermined rotational position.

In this embodiment, the ignition is performed in the order of 1-3-4-2, so in order to avoid mutual interference of intake air, the opening positions for the first and fourth cylinders and the opening positions for the second and third cylinders are determined. and are formed with the same orientation. As shown in FIG. 1, the rotation shaft 18a of the timing valve 18 is connected to a pulley 23 via an advance mechanism 22. As shown in FIG. The pulley 23 is connected via a belt 26 to a drive pulley 25 attached to the end of the crankshaft 24.

In this embodiment, the opening 21 is constituted by a through hole, and since the timing valve 18 is opened every half turn, the timing valve 18 is rotated at 1/2 the speed of the crankshaft 24.

Therefore, the diameter of the pulley 23 for the timing valve 18 is set to twice the diameter of the drive pulley 25 of the crankshaft 24.

The advance mechanism 22 includes a helical gear 27 attached to the end of the rotating shaft 23a of the pulley 23, and a timing valve 18.
a helical gear 28 disposed opposite the helical gear 27 on the pulley 23 side attached to the end of the rotating ring 18a, and an adjustment piece 2 meshing with both helical gears 27 and 28.
9. The adjustment piece 29 can change the meshing position with the helical gears 27 and 28 in the direction of the rotation axis of the timing valve 18. When the adjustment piece 29 moves in the axial direction and the meshing position changes, the helical gear 27.
The relative rotational position with respect to 28 changes, thereby changing the advance angle field.

An actuator 30 is provided to adjust the axial position of the adjustment piece 29.
is preferably operated by a command signal from a control unit 31 incorporating a microcomputer. In this embodiment, a signal N representing the engine speed is input to the control unit 31, and the control unit 31 determines the amount of advance according to this speed signal, and controls the actuator 3.
0 to drive the advance angle mechanism 22.

Further, the control unit 31 is configured to also input an engine load signal, and the control unit 31
outputs a command signal to the actuator 20a of the bypass valve 20 to open the bypass valve 20 in a predetermined operating range according to the rotation speed and the load value.

In the above structure, in this embodiment, the timing valve 18
rotates at 1/2 the speed of the crankshaft 24. Therefore, the opening 21 of the timing valve 18 is the intake passage 9 of each cylinder.
The timing of communication, that is, the opening period of the timing valve 18 corresponds to the opening period of the intake valve 11 of each cylinder. In this embodiment, the period during which the intake valve 11 is open and the timing valve 18 is open is when intake air is substantially introduced into the combustion chamber 6, and therefore, this period is the effective valve opening period. .

Referring to FIG. 3 in conjunction with FIG. 3, the opening period of the timing valve 18 is changed according to the engine speed N, and as the engine speed N increases, the timing changes as shown by the solid line in the figure. The opening timing of the valve 18 is set to approach the opening timing of the intake valve 11. On the other hand, engine 1
When the rotational speed of the timing valve 18 becomes lower, the opening timing of the timing valve 18 is shifted to the lag side by the action 2)J of the advance angle mechanism 22, as shown by the broken line in the figure. When the timing valve 18 inquires, intake air is actually introduced into the combustion chamber 6, but when the valve opens, a negative pressure wave of the intake air is generated on the downstream side of the timing valve 18, and this negative pressure wave It reaches the main intake passage 13 through the auxiliary intake passage 9a.

At a point 9b where the sub-intake passages 9a and 9a of the main intake passage 13 merge, the negative pressure wave is a first wave whose phase is shifted by half a wave from each other.
The second, third, and fourth cylinders interfere with each other, and the negative pressure waves that interfere are reversed and return as positive pressure waves, which finally reach the combustion chamber 6.

In this embodiment, the intake system is configured so that this positive pressure wave reaches the combustion chamber 6 at the end of the intake stroke. It is designed to increase high filling efficiency. and,
Considering that the larger the amplitude of the negative pressure wave generated when the timing valve 18 is opened, the larger the reverse positive pressure wave will be generated, resulting in a larger filling efficiency increasing effect, in this embodiment, the piston speed is slow, and therefore, At low rotation speeds, when the generated negative pressure wave tends to be small, the timing valve 1
The opening timing of the valve No. 8 is delayed compared to when the rotation speed is high, so that a larger negative pressure wave is generated.

In addition, the engine rotational speed, that is, the tuned rotational speed N (rIIIl) at which the effect of increasing the filling rate due to the pressure wave can be obtained, is determined by the effective valve opening period θe (deg) and the intake system's specific motion number ν(
+12) is expressed as N-θe·ν/6, but in the device of this embodiment, the advance mechanism 22 is used to change the effective valve opening period θe from θn+ax to θ1n according to the change in the rotation speed. , it is possible to obtain a synchronized rotation speed over a wide rotation speed range, and as a result, a wide rotation speed range from low rotation to medium rotation (N1 to N2)
It is possible to obtain the effect of increasing the filling rate.

Here, when the engine 10 rotation speed is higher than N2, even if the timing valve 18 is shifted to the advance side from θl1lin, the passage resistance will increase, which will have a negative effect on ensuring a high filling amount. There is a rift.

Therefore, in this embodiment, when the rotation is high above N2, the actuator 20a is operated to open the bypass valve 20,
The two-way υI control by the timing valve 18 is released, and the required three intake airs are introduced from another intake passage 9 via the bypass passage 19.

In addition, in the rotation range where the engine 1 rotation speed is lower than N1, the amount near the timing valve 18 is increased to θ+max.
If the setting is left as is, the timing between the intake valves 110 and the timing between the timing valves 18 will deviate significantly, causing
The output of the engine 1 is lower than when the interval is not implemented.

Therefore, in this embodiment, the actuator 20a is operated during low rotations below N1, and the control by the timing valve 18 is canceled in the near future.

In other words, in the intake air control tIl implementation of the engine 1 of this embodiment, when the engine 1 rotational speed is between N1 and N2, the timing valve 18 is controlled to be retarded 1 by θmax to θ according to the rotational speed.
It is variable intermittently or continuously up to 1n to increase the filling effect by pushing the negative pressure wave, and in the rotation range before and after that (lower than N1, higher than N2), the intake week by the timing valve 18 is not controlled. I am trying to avoid the negative effects of control in the near future.

Therefore, in general, it is realistic that the variable range of control during the intake week is approximately 20% of the rotation speed of engine 1, so the continuous 1-pu control range is Even if the engine rotational speed is set on the high side and the intake air filling effect is obtained over a wide range, the decrease in engine torque in the uncontrollable region can be minimized as much as possible.

4 to 6 show a second actual cancer example of the present invention.

In the embodiment shown in the figure, the present invention is applied to a type 6 six-cylinder engine 1', in which the intake passages 9 of the first to third cylinders are merged by an auxiliary intake passage 9a-, and the Fifth
The intake passages 9 of the cylinders are joined by another 01 intake passage 98', and each sub-intake passage 9a'' is individually provided with a timing valve 18-.18-.

The timing valve 18' has a hollow cylindrical shape, and an opening 21-, which communicates with the intake passage 9 of each cylinder at a predetermined rotational position, is provided in the peripheral wall of the timing valve 18', corresponding to each cylinder.

In this embodiment, the timing valve 18- is connected to the engine 1.
The diameter of the pulley 23' is set to correspond to the rotation speed of the pulley 23'.

Therefore, the a11 intake passages 9a-, 9a- are merged on the upstream side to form the main intake passage 13, and the 01 intake passage 9 is formed between the main intake passage 13 and the timing valve 18'.
A control valve 32 is provided to communicate between a- and 9a-.

Moreover, each timing valve 18-. As shown in FIG. 5, the intake passage 9 on the downstream side of the intake passage 18- is provided with a N-open release valve 33 for partially opening and closing the intake passage 9, respectively.

During this period, the release valve 33 receives the output signal from the control unit 31 and operates the actuator 2 as in the above embodiment.
0a, and when the release valve 33 is opened, the opening timing of the intake valve 11 and the same timing of the timing valve 18- overlap, and the immediate damage caused by the timing valve 18' is substantially canceled.

Now, in the intake control device of this embodiment configured as described above, as shown in FIG.
In the rotation range of N1 to N2, the intake period of the timing valve 18' is controlled in the same way as in the above embodiment.
When the control valve 32 is opened, the resonance point moves from NRI to NR2.

Therefore, due to the proximity of the timing valve 18', the resonance point NR1 is moved to the lower speed side, and the resonance point NR2 is moved to the lower speed side.
If the specifications of the intake system are selected so that the intake system can be moved approximately midway between NR1 and NR2, high torque performance can be obtained over a wide range from low speed to high speed.

In this embodiment as well, in the region where the engine speed is lower than N1, the region between N2 and N3, and the region higher than N5, the control valve 33 is operated in the vicinity of each, and the control valve 33 is operated in the vicinity of the timing valve 18'. By canceling the above, the same effects as in the first embodiment can be obtained.

FIG. 7 shows a third embodiment of the present invention. In this embodiment, the basic structure is the same as that of the first embodiment shown in FIG. and sub-intake passage 9a.
The intake passage of the intake passage 9 is formed only by the main intake passage 13'.

A timing valve 18'' corresponding to the four-cylinder engine 1 and having the same structure as the timing valve 18' shown in FIG. 4 is provided in the main intake passage 13', and a throttle valve 17 is provided upstream thereof. Further, on the upstream side thereof, there is provided a volume portion 16 having a certain volume for reversing the negative pressure wave generated in the intake system.

Further, one end of the bypass passage 19- provided downstream of the timing valve 18'' communicates with the main intake passage 13' downstream of the throttle valve 17 via the communication portion 34, and when the bypass valve 2o is opened, It is configured to introduce intake air into each intake passage 9 via the communication portion 34.

In this embodiment, the negative pressure wave generated on the downstream side of the timing valve 18'' due to the downward movement of the piston 4 is reversed in the volume portion 16 and becomes a positive pressure wave, which reaches the combustion chamber 6.

In addition, in the intake system of this embodiment, similarly to the first embodiment, the timing valve 18'' is opened and released by controlling the bypass valve 20 in the rotational speed range before and after the control.

Note that the advance angle mechanism 22 of this embodiment is almost the same as that of the first embodiment, but the pulley 23 attached to the rotation @ 23a
- is set to the same diameter as the drive pulley 25.

FIGS. 8 and 9 show a fourth embodiment of the present invention, and in this embodiment, the steps shown in FIGS.
The intake system natural frequency ν variable line drawing for a six-cylinder engine is applied to an in-line four-cylinder engine, and in this example, the first
．． The intake passage 9 of the fourth cylinder, the second cylinder. The intake passages 9 of the third cylinder are joined to each other by sub-intake passages 9a, 9a, and timing valves 18'' corresponding to the two cylinders are provided in the sub-intake passages 9a, 9a, respectively, and the sub-intake passages 9a.

9a is provided with a control valve 32' which allows these ports to communicate with each other.

Furthermore, gears 35 and 35 having the same diameter and meshing with each other are attached to the rotating shaft 23a' of the timing valve 18'', and a drive pulley attached to the crankshaft 24 is attached to one rotating shaft 23a-. A pulley 23 '' having the same diameter as 25 is connected via a belt 26 .

Incidentally, an advance angle mechanism 22 is attached between the pulley 23'' and the gear 35.

Further, in the intake passage 9 on the downstream side of each timing valve 18'', a release valve 33 having the same configuration as in FIG. 5(a) is installed.

The intake control device configured as described above is controlled in the same manner as the second embodiment shown in FIG. 4, and the same effects can be obtained.

In the above embodiments, all timing valves 18.
18-. In the weeks 18" and 18"', the case where the control is canceled also on the high speed side of the engines 1 and 1- was exemplified, but
The release may be performed only on the low rotation side.

Further, in the above embodiments, an example in which the present invention is applied to a reciprocating engine has been described, but the present invention can be similarly applied to a rotary piston engine.

(Effects of the Invention) As described in detail in the embodiments above, according to the engine intake device according to the present invention, the opening timing of the timing valve is controlled in a predetermined rotation range of the engine, and the actual intake start timing is By delaying the timing, while ensuring the effect of increasing intake air filling obtained by reversing the negative pressure wave, the timing valve's timing is canceled at least on the low speed side of the variable range. During the week, there is no significant difference between the timing and the intake timing, and a significant drop in engine torque due to this can be avoided.

[Brief explanation of the drawing]

FIG. 1 is a schematic diagram of an engine showing a first embodiment of the present invention;
Figure 2 is a detailed sectional view of the main part of Figure 1, Figure 3 (a) is a diagram showing the opening timing of the intake valve and timing valve, and Figure 3 (b) is a diagram showing the timing valve control and its operation. FIG. 3 is a diagram showing the relationship between the release and the engine rotation speed. Fourth
The figure is a schematic diagram of the engine showing the second embodiment, and FIG.
) is an explanatory diagram of another embodiment of the timing valve release means, FIG. 5(b) is an explanatory diagram of the operation of the same release means, and FIG. be. FIG. 7 is a schematic diagram of an engine showing the third embodiment. FIG. 8 is a schematic diagram of an engine showing the fourth embodiment, and FIG. 9 is an explanatory diagram of the control state of the engine of the embodiment shown in FIG. 1.1'... Engine 6... Combustion chamber 9.
...Intake passage 11...Intake valve 18.1
8", 18'!, 18"'...Timing valve 19, 19'...Bypass passage 20...Bypass valve 22...Advance mechanism 31...Control unit patent applicant Mazda Corporation Company agent Patent attorney - Kensuke Shiro Patent attorney Masari Matsumoto Flute 1 Figure 3 Engine rotation speed Figure 6 Control meter Engine rice rolling Figure 4 Figure 5 Procedures 11 official book (method) 6゜Showa November 9, 1962 7゜ Commissioner of the Japan Patent Office Kunio Ogawa 1, Indication of the case Patent Application No. 129853, filed in 1988 Address 3-1 Shinchi, Fuchu-cho, Aki-gun, Hiroshima Name Name Ma
Tsuda Co., Ltd. 4, agent address: 12-7, Shinbashi 2-I, Minato-ku, Tokyo, IQ, 27, 1986 (shipment date) "Brief explanation of drawings" column of the ML document subject to amendment From page 22, line 6 [1st line] to page 8, line 8 [Figure 3(a) 4..., Figure 3(b) is]”
The statement has been corrected to read, ``Figure 3C is a diagram showing the opening timing of the intake valve and the timing valve.''

Claims (1)

[Claims] A timing valve that is provided on the upstream side of an intake port of an intake passage communicating with a combustion chamber of an engine and delays the intake start timing from the intake top dead center of the combustion chamber, and a canceling means that cancels the intake start timing delay caused by the timing valve. and an engine rotation speed detection means for detecting the engine rotation speed, and an intake start timing delay control by the timing valve is performed in a predetermined rotation range according to the output of the engine rotation speed detection means, and at least at a low speed in the predetermined rotation speed range. An intake air control device for an engine, comprising a release control means for activating the release means on the side.