JPH0338414Y2 - - Google Patents

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to an internal combustion engine equipped with a mechanical supercharger, and particularly to an intake passage control device for a mechanical supercharger that prevents noise in the intake system.

[Prior art]

In an internal combustion engine equipped with a mechanical supercharger, a bypass passage is provided upstream and downstream of the supercharger, and the bypass passage is opened except during high-load supercharging to divert air discharged from the supercharger to the upstream side of the intake passage. It is common to bypass (reverse flow) to the side. However, when the engine suddenly decelerates during high-load operation, almost all of the air discharged from the supercharger is bypassed to the upstream side, producing pulsating noise. This pulsating noise is also generated in a system that uses an electromagnetic clutch or the like to stop the operation of the supercharger during deceleration, and is radiated to the outside of the engine.

[Problems to be solved by the invention] The invention provides a mechanical supercharger in the intake passage, a throttle valve downstream of the supercharger, and a connection between the supercharger and the throttle valve. The purpose of this invention is to prevent the above-mentioned pulsating noise generated when reverse flow through the bypass passage from being dissipated to the outside of the engine in an internal combustion engine provided with a bypass passage that bypasses the intake passage to the upstream side of a supercharger.

[Means for solving problems]

According to the present invention, in an internal combustion engine equipped with a mechanical supercharger as described above, a normally open shutoff valve is provided in the intake passage upstream of the bypass passage opening upstream of the turbocharger, and the bypass passage is provided with a normally open shutoff valve. An intake passage control device for a mechanical supercharger is proposed in which the shutoff valve is fully closed under predetermined operating conditions in which the amount of air is large, thereby blocking pulsating noise that is about to be emitted upstream of the intake passage.

[Example 1] FIG. 1 is a schematic diagram of Example 1 of the present invention. In Fig. 1, 1 is an air cleaner, 2 is an air flow meter, 3 is an intake passage, 9 is a supercharger, 10 is a bypass passage, 11 is an electromagnetic clutch, 12 is a bypass valve, 13 is a rod, 14 is a link, and 15 is a 16 is a throttle valve, 18 is an internal combustion engine main body, and 19 is a belt, and these structures are similar to conventionally known internal combustion engines equipped with a mechanical supercharger.

That is, the throttle valve 16 is provided as close as possible to the engine body 18 on the downstream side of the mechanical supercharger 9, and the intake passage portion 3a between the supercharger 9 and the throttle valve 16 is located downstream of the mechanical supercharger 9. It is bypassed to the upstream side of the intake passage portion 3b via a bypass passage 10, and this bypass passage 10 is provided with a bypass valve 12.

Throttle valve 16 is rod 15, link 1
4. It is mechanically connected to the bypass valve 12 via the rod 13, and when the throttle valve 16 is opened from the state shown in the figure, the bypass valve 12 opens.
operates to gradually close.

The mechanically driven supercharger 9 that supercharges intake air is, for example, a Roots pump type supercharger, in which a pair of Roots-type rotors rotate within a housing and perform a pumping action to supercharge intake air. It is something to do. Of course, a supercharger consisting of a vane pump may be used instead of the Roots pump. The supercharger 9 is connected to the crankshaft of the internal combustion engine 18 via a belt 19, and when the electromagnetic clutch 11 is connected, it is rotated at a rotational speed corresponding to the engine rotational speed.

In the present invention, a normally open cutoff valve 4 is provided further upstream than the opening of the bypass passage 10 in the intake passage portion 3b on the upstream side of the supercharger 9.
The solenoid valve 6, which is made up of a coil 7, a spring 8, and a rod 5, is closed as shown in the figure by energizing it, and opened by cutting off the energization.

The electromagnetic clutch 11 of the supercharger 9 and the electromagnetic valve 6 for opening and closing the cutoff valve 4 are operated by control signals from the control device 20. The control device 20 receives an intake air amount signal from the air flow meter 2, a throttle valve 16 opening signal from the throttle opening sensor 17, and an engine rotation signal from the ignition device 21. Various calculations are performed within the controller to output control signals to the electromagnetic clutch 11 and electromagnetic valve 6 described above.

When the engine is idling, the throttle valve 16
is closed as shown in FIG. 1, and bypass valve 12 is open. On the other hand, the electromagnetic valve 6 is not energized and the cutoff valve 4 is open. During medium load, when the throttle opening or intake air amount/engine speed (Q/N) reaches a predetermined value, the electromagnetic clutch 11 is activated as is known.
The supercharger 9 is activated and supercharged. At full load, the throttle valve 16 is fully open, the bypass valve 12 is fully closed, and the engine is fully supercharged, as is known.

When the engine is decelerating, the throttle valve 16
The bypass valve 12 operates as shown in FIG. 1, as in the case of idling, and almost all of the air discharged from the supercharger 9 flows back into the upstream intake passage 3b of the supercharger 9 through the bypass passage 10. do. This backflow causes pulsating noise. In the first embodiment, when the throttle valve 16 is fully closed and the engine speed is above a predetermined speed, the electromagnetic valve 6 is energized and the cutoff valve 4 is closed. Therefore, the shutoff valve 4 prevents the pulsating noise generated by the reverse flow through the bypass passage 10 from flowing out through the intake passage 3 and the air cleaner 1 to the outside.

FIG. 2 is a flowchart showing a method of controlling the solenoid valve 6 in the first embodiment. First, the (throttle valve opening) signal from the throttle opening sensor 17 is taken in, and if the idle switch (hereinafter referred to as LL) is ON, that is, the throttle valve 16 is fully closed, then the engine signal from the ignition device 21 is A rotational speed signal is taken in, and if the engine rotational speed Ne is greater than a predetermined value x, the solenoid valve 6 is turned on and the cutoff valve 4 is closed. At other times, turn off the solenoid valve and shut off valve 4.
is open.

[Example 2] In FIG. 3, the parts numbered 1 to 21 are the same as in Example 1. In the second embodiment, an upstream pressure sensor 22 is provided in the upstream intake passage portion 3b of the supercharger 9.
A downstream pressure sensor 23 is provided in each of the downstream intake passages 3a. Shutoff valve 14, throttle valve 1
6 is the same as in Example 1. The control device 20 receives an intake air amount signal from the air flow meter 2, a throttle opening signal from the throttle opening sensor 17, and an engine rotation signal from the ignition device 21, as well as a pressure sensor 22 upstream of the supercharger and a pressure sensor downstream. 23
The electromagnetic clutch 11 and the electromagnetic valve 6 are actuated by taking in the pressure signal and performing various calculations.

In the second embodiment, during idling, medium load, and full load, the operation is similar to that in the first embodiment. During deceleration, when the throttle valve 16 is fully closed and the difference between the pressures detected by the pressure sensors 22 and 23 is greater than a predetermined value, the electromagnetic valve 6 is energized and the cutoff valve 4 is closed.

FIG. 4 is a flowchart showing a method of controlling the solenoid valve 6 in the second embodiment. If LL ON,
The pressure signals P ₁ and P ₂ from the sensors 22 and 23 are taken in, and if P ₂ - P ₁ is greater than a predetermined value y, the solenoid valve 6 is turned ON, and otherwise, the solenoid valve 6 is turned OFF. Other configurations and operations are the same as in the first embodiment.

[Embodiment 3] In FIG. 5, parts numbered 1 to 21 are the same as in Embodiment 1. In the third embodiment, an air flow meter 30 is provided in the middle of the bypass path 10. In addition to the intake air amount signal from the air flow meter 2, the throttle opening signal from the throttle opening sensor 17, and the engine rotation signal from the ignition device 21, the control device 20 receives the air flow rate from the air flow meter 30 of the bypass passage 10. The signal is taken in, various calculations are performed, and the electromagnetic clutch 11 and electromagnetic valve 6 are operated.

Embodiment 3 operates in the same manner as Embodiment 1 during idling, medium load, and full load, but during deceleration, the throttle valve 16 is fully closed (LL ON) as shown in the flowchart of FIG. Moreover, when the air flow meter 30 determines that the amount of air flowing backward through the bypass path 10 from the downstream side to the upstream side of the supercharger is greater than the predetermined amount Z, the solenoid valve 6 is energized and the cutoff valve 4 is closed. Other configurations and operations are the same as in Example 1.

[Example 4] In FIG. 7, parts numbered 1 to 21 are the same as in Example 1. In the fourth embodiment, a rotation speed sensor indicated by reference numeral 40 is attached to the supercharger 9 to detect the rotation speed of the supercharger 9.

Embodiment 4 operates in the same manner as Embodiment 1 during idling, medium load, and full load, but during deceleration, the throttle valve 16 is fully closed (LL ON) as shown in the flowchart of FIG. Moreover, when the rotation speed sensor 40 determines that the rotation speed Np of the supercharger 9 is greater than the predetermined rotation speed a, the electromagnetic valve 6 is energized and the cutoff valve 4 is closed.

In addition to the above Examples 1 to 4, it is of course possible to use all or some of the various sensors used in these Examples in combination.

In addition, in each of the above embodiments, it is described that the isolation valve 4 is fully closed, but if the intake passage is secured and the isolation valve 4 is closed, the sound isolation effect will be lower than when it is fully closed. However, when the engine speed drops due to insufficient air supply due to full closure, the shutoff valve 4
It is also readily apparent to those skilled in the art that no control device is required for opening.

[Effect of idea]

According to the present invention, the pulsating sound of air flowing backward through the bypass passage 10 is prevented from dissipating to the outside of the engine through the air cleaner 1, especially when the engine is in a decelerating state. As a result, noise can be prevented even when the throttle valve 16 is installed downstream of the supercharger 9, and since the throttle valve 16 can be installed as close to the engine body 18 as possible, the response of the engine can be improved. becomes good. Further, it is possible to prevent the air flow meter 2 from swinging due to the pulsation of the air flowing backward, thereby preventing malfunctions in fuel supply.

[Brief explanation of the drawing]

FIG. 1 is a schematic diagram of Embodiment 1 of the present invention, FIG. 2 is a flowchart showing the operation of Embodiment 1, FIGS. 3 and 4 are schematic diagrams and flowcharts of Embodiment 2, and FIGS. FIG. 6 is a schematic diagram and flowchart of Example 3, and FIGS. 7 and 8 are schematic diagrams and flowchart of Example 4. 2...Air flow meter, 3...Intake passage, 4
...Shutoff valve, 6...Solenoid valve, 9...Supercharger, 10
...Bypass path, 12...Bypass valve, 16...
Throttle valve, 17... Throttle opening sensor, 18... Engine body, 20... Control device.

Claims (1)

[Scope of utility model registration request] A mechanical supercharger is provided in the intake passage, a throttle valve is provided downstream of the supercharger, and a bypass passage is provided to bypass the intake passage between the supercharger and the throttle valve to the upstream side of the supercharger. In the internal combustion engine provided with the above-mentioned internal combustion engine, a normally open shutoff valve is provided in the intake passage upstream of the bypass passage opening upstream of the turbocharger, and the shutoff valve is closed under predetermined operating conditions in which a large amount of air flows backward through the bypass passage. An intake passage control device for a mechanical supercharger that is fully closed to block pulsating noise that is being emitted upstream of the intake passage.