JPS5827812A - Supercharger of internal-combustion engine - Google Patents

Abstract

PURPOSE:To reduce the torque variation at the time of mutual transfer of supercharging and improve the drivability of an engine by carrying out mechanical supercharging within a substantially middle speed rotational range of the engine, and inertial supercharging within the rotational ranges of higher rotational speed than the middle speed rotational range. CONSTITUTION:Transfer from mechanical supercharging to inertial supercharging or the reverse is carried out by providing a check valve 10 within a suction passage 9. When the rotation of an engine 1 exceeds middle rotational speed, the amount of air from a supercharger 2 becomes rather insufficient as compared to the amount of suction air to the engine 1, so the pressure within the suction passage becomes lower than the atmospheric air pressure and the check valve 10 is opened, thus inertial supercharging driving is performed. On the other hand, at a speed less than the middle speed, the amount of air from the supercharger 2 becomes more than that of the engine 1, and the pressure within the suction passage 9 becomes higher than that of the atmospheric air, thus the check valve 10 is closed and the mechanical supercharging state is resulted. By this procedure, when the check valve 10 is opened or closed, the pressure at both sides interposing the check valve therebetween becomes equal to the atmospheric pressure. Since a balancing zone is formed as a kind of a buffer zone, the variation of the suction pressure at the time of the above supercharging transfer becomes smooth.

Description

DETAILED DESCRIPTION OF THE INVENTION Seikan 8J4 relates to a supercharging device for the intake system of an internal combustion engine.

It is widely known that supercharging is used as a means of increasing the output and fuel efficiency of internal combustion engines, and three types of supercharging are known: exhaust turbo supercharging, mechanical supercharging, and inertial supercharging. Exhaust turbocharging uses the energy of the exhaust gas from the engine to drive the turbosupercharger, so even though it is extremely effective in medium to high speed rotation ranges where the energy of exhaust gas is large, it is In a slower rotation range, not only can no improvement in output be expected, but the responsiveness at the beginning of engine acceleration is poor, and there is a risk of supercharging due to the inertial rotation of the turbocharger during deceleration. Mechanical supercharging, on the other hand, uses the engine to rotate the supercharger, so it is effective even in the low engine speed range, has good acceleration response, and has advantages such as no supercharging during deceleration. On the other hand, the VCtd supercharger that secures a predetermined amount of intake air in the high speed range of the engine must be made considerably large. Not only is it not applicable to modern cars where the engine room is small and the front part of the car has a wedge-shaped nose shape from the viewpoint of air resistance, or where the space for installing the engine is limited in small cars, it also has high rotation speeds. There is a problem with the durability of the supercharger in the region, and
The power loss required to drive the supercharger increases approximately squarely with the rotational speed. Inertial supercharging also involves installing a surge tank on the intake line to the engine, and adjusting the length of the intake passage from the surge tank to the combustion chamber so that the amount of intake air is at its maximum in a specific rotation range where the engine is frequently used. Naruyo V
C setting, the structure is simpler than the above two, and the installation space does not increase dramatically, but on the other hand, it is effective in inertial supercharging in rotation ranges other than the above-mentioned specific rotation range. I couldn't get it.

In order to take advantage of the advantages of mechanical supercharging and inertial supercharging, the present invention performs mechanical supercharging up to a substantially medium rotational speed range of the engine, and performs inertial supercharging above that speed range. That is, in the diagram showing the relationship between engine rotation speed and output in Figure 1,
In contrast to the non-supercharging torque curve hole, when mechanical supercharging is performed, high performance is achieved in the rotation range below approximately medium speed of the engine, as in the case of mechanical supercharging. When using the curve (Q), considering that high performance is achieved in the rotation range above approximately medium speed rotation, mechanical supercharging is applied in the low to medium speed rotation range at approximately medium speed rotation, and Inertia supercharging is performed in the medium to high speed range of the engine to improve output over the entire engine speed range.

However, if this is done, torque fluctuations will occur in the engine output when switching from mechanical supercharging to inertia supercharging or from inertia supercharging to mechanical supercharging in the medium-speed rotation range, resulting in poor driver stability. Therefore, in the present invention, by providing a check valve in the intake system to perform the switching, torque fluctuations at the time of mutual switching between mechanical supercharging and inertial supercharging can be reduced and smooth switching can be achieved. In addition, the purpose of the pond is to completely stop the drive of the mechanical supercharger during inertia supercharging, reducing the durability of the mechanical supercharger and reducing the drive. Another purpose of the VC is to prevent an increase in power loss and to automatically control the boost pressure to a constant value during mechanical supercharging.

To explain the drawings of the embodiment below, in the figure (1
) indicates a multi-cylinder internal combustion engine, (2) indicates a positive displacement supercharger such as Roots, I-wing or reciprocating type, and the supercharger (2) is:
A power transmission mechanism such as a belt (4) or the like is connected from the engine shaft (3) or the like of the engine (1) with a relatively small capacity so as to perform predetermined supercharging only in a rotation range below approximately medium speed rotation of the engine. Rotationally driven through.

(5) is a surge tank for inertial supercharging, and the surge tank (5) is connected to the intake port (6) in each cylinder of the engine [1].
are connected to each other through independent intake pipes (7), and an opening into the surge tank (5) from the point where the intake port (6) in each cylinder opens into the combustion chamber of that cylinder. The intake passage length is 1. The length is set such that the amount of intake air is maximum in a rotation range of the engine that is approximately at or above a medium speed range.

(8) is an air cleaner, and an intake passage (9) connecting the air cleaner (8) and the surge tank (5) Vc//
It is sufficient to install an air flow meter (I51) and a throttle valve (16) as shown by the dashed line from the air cleaner (8), and in the case of a diesel engine, the intake passage (9)
No air flow meter or throttle valve is required inside.

In such a configuration, when the engine speed does not reach approximately medium speed, the intake passage (
9) VC is pressurized and supplied with air that is greater than the intake air amount of the engine, and the pressure inside the intake passage (9) becomes greater than atmospheric pressure, causing the check valve to close to 0.
(Since m closes to prevent backflow to the air cleaner (8) side, all of the pressurized air from the supercharger 5 (2) is sent to the engine, and the engine is operated with so-called mechanical supercharging.

Then, when the engine speed increases to a rotation range of approximately medium speed or higher, the amount of air from the supercharger (2) becomes insufficient relative to the amount of intake air to the engine, and the intake passage (9 ) approaches the atmosphere and then drops below the atmosphere, opening the check valve 00, so atmospheric air from the air cleaner (8) is directly introduced into the intake passage +91 VC through the check valve αQ. At this time, the length a of the intake passage from the surge tank (5) to the combustion chamber of each cylinder is set so that the amount of intake air is maximum in the engine speed range above approximately medium speed. In the rotation range above speed, the engine is operated with so-called inertia supercharging.

Also, when the engine speed decelerates from a medium speed or higher speed range to a medium speed or lower speed range, the amount of air from the supercharger (2) becomes larger than the amount of intake air of the engine, and the intake passage (9) Since the internal pressure becomes higher than atmospheric pressure and the check valve G[) closes, the mechanical supercharging state starts from this point on.

In this case, there is no check valve in the intake passage (9). OKInstead, by providing an on-off valve and switching between mechanical supercharging and inertial supercharging by opening and closing the on-off valve, it is possible to prevent the intake pressure from suddenly crossing atmospheric pressure before and after opening and closing the on-off valve. The torque of the engine changes accordingly, and the switching between mechanical supercharging and inertial supercharging is
Simply turn on/off the turbocharger without using a reverse valve
Even if the check valve 00 is installed in the intake passage (9) as described above, a sudden change will occur in the intake pressure and cause a fluctuation in the engine torque. When the check valve a0 opens or closes, the check valve 0
There is an equilibrium zone in which the pressure on both sides becomes approximately atmospheric pressure, and after this equilibrium zone the pressure shifts to above or below the atmosphere, and this equilibrium zone becomes a kind of buffer zone, so mechanical overload is prevented. Changes in intake pressure at the time of transition from air supply to inertia supercharging and from inertia supercharging to mechanical supercharging become smooth, making it possible to reduce engine torque fluctuations.

As described above, according to the present invention, it is possible to reduce torque fluctuations at the time of transition between mechanical supercharging and inertial supercharging, but even in inertial supercharging in a rotation range above approximately medium speed rotation of the engine, the supercharger (2) I drove it! If the supercharger (2) is left in a state of inertia supercharging, the durability of the supercharger (2) will be reduced and the power loss of the engine will be caused. suggest something.

That is, a means for turning on or off the power transmission to the supercharger (2), for example, an electromagnetic clutch mouth, is provided in the power transmission mechanism to the supercharger (2), and the electromagnetic clutch 07) is connected to the rotation speeder (18) of the engine.
) through the control circuit (19), and when the rotational speed of the engine (1) rises to m-4, where it becomes an inertial supercharging state of approximately medium speed or higher, the clutch U force is turned OFF and the supercharger (2 ) is stopped, and when the speed drops below approximately medium speed, the supercharger (2) is driven by turning on the clutch Oη, or in the case of a gasoline engine, the electromagnetic clutch (Iη is controlled by the throttle via the control circuit (19)). In relation to the valve (14) or (16), when the throttle valve (I4 or 06) is fully open or close to fully open, the clutch (lη is turned OFF) so that the supercharger (2
).

In this way, the drive 1 of the supercharger is stopped during operation with inertial supercharging, so the supercharger is not wasted and the durability of the supercharger is reduced and the power loss of the engine is lost. can be reliably prevented.

Furthermore, in order to prevent supercharging pressure from increasing unnecessarily during mechanical supercharging, a check valve [1G
A VC pressure sensor is provided on the downstream side or surge sensor +5), and the pressure sensor +j-'20) is connected to the control circuit 119.
One force transmission iON such as the electromagnetic clutch (1η etc.)
Or, in relation to the means for turning off, if the supercharging pressure becomes higher than a certain value, the supercharger (
2) should be stopped. In addition, the intake passage (9
) A bypass passage 1211 is provided as shown in FIG. 3 for the check valve GO+ provided in the bypass passage (2I).
Inside, there is a Taisephram type regulating valve (2
21 or a bypass passage 1 as shown in FIG.
21) Adjustment check valve opposite to K check valve αO (5))
, and the adjusting check valve Yu is configured to open when the pressure on the downstream side of the check valve (L() becomes equal to or higher than a certain boost pressure (in this case, the adjusting check valve Y-4423 + can be integrated with check valve α0), check valve α0
If a means is provided to release the boost pressure to the atmosphere when the downstream pressure exceeds a certain boost pressure, the boost pressure during mechanical boosting will be able to exceed a certain value. Therefore, it is possible to prevent the engine from being damaged due to high supercharging.

In summary, the first invention supercharges the engine by mechanical supercharging in the engine speed range below approximately medium speed, and by inertial supercharging in the engine speed range above that. The turbocharger used in this process can be a small one with a small capacity that is suitable for the engine's rotation range below approximately medium speed, so it can be easily applied to small cars and nose-heavy cars. V in the intake passage
Since this is carried out by the inverse ratio valve provided with C, it is possible to significantly reduce the torque variation 1 in the engine output during the movement switching.The second invention, in addition to the first invention, improves the durability of the supercharger. This has the effect of reliably preventing a decrease in engine power and an increase in engine power loss.

[Brief explanation of the drawing]

Fig. 1 is a diagram showing the relationship between engine speed and output, Fig. 2 is a diagram of an apparatus according to an embodiment of the present invention, and Figs. 3 and 4 are diagrams showing main parts of other embodiments of the present invention. It is. (1)...Engine, (2)...Supercharger, (4)...
Belt, (5)...surge tank, (8)...air cleaner, (9)...intake passage, αG...check valve,
(l)... Bypass passage, (Iη... Electromagnetic clutch. Figure 1 5-1 Procedural amendment (voluntary) September 2, 1981 and Japan Patent Office Commissioner Shima 1) Haru Judono 2 Invention' ) No. 8 Internal combustion engine supercharging device 3, Relationship to the case of the person making the amendment Patent applicant address: 1-1-4 Daihatsu-cho, Ikeda-shi, Osaka Prefecture, Agent 5. Amendment/subject Description (month, details) Add the following sentence next to "From reach (8)" on page 6, line 19 of the book.] A check valve 01 that opens only in the direction of the surge tank (5) is provided, and the reverse The suction passage 0]) to the supercharger (2) is located upstream of the valve 01, and the supercharging f@(2) is located downstream of the valve 01.
Connect the discharge passages α from + to each other. In this case, in the case of a carburetor type internal combustion engine, a carburetor 03 with a throttle valve 0 valve is installed in the intake passage (9) as shown by the two-dot chain line, and in the case of a fuel injection type internal combustion engine, (2), page 10, lines 4-5, ``When I throttled...'' was corrected to the following sentence. "In relation to the throttle valve Q4 of the carburetor q4 shown by the two-dot chain line or the throttle valve (3) shown by the one-dot chain line provided in the intake system, the throttle valve 0 or (a) is fully open or close to fully open, and When the engine speed is approximately medium speed or higher, ``(3), ``upstream of the check valve QQ'' is added in front of ``(3), page 11, line 10, 1 atmosphere''.

Claims (1)

[Claims] (1) A surge tank is provided in the intake passage leading from the air cleaner to the cylinder of the engine, and the length of the intake passage from the surge tank to the cylinder is increased in the rotation range of approximately medium speed or higher of the engine. A check valve is installed in the intake passage from the air cleaner to open only from the air cleaner toward the cylinders of the engine. A supercharger having a capacity suitable for the amount of intake air in the @J transition region of approximately medium speed or lower is connected via a power transmission mechanism, and the discharge port of the supercharger is connected to the intake passage on the downstream side of the reversal valve. A supercharging device for an internal combustion engine, characterized in that: [2] Claim No. 1 characterized in that the check valve is provided with means for releasing supercharging pressure to the atmosphere when the pressure on the downstream side thereof exceeds a certain supercharging pressure. A supercharging device for an internal combustion engine according to item 1. (3) A surge tank is provided in the intake passage leading from the air cleaner to the engine cylinder, and the length of the intake passage from the surge tank to the cylinder is adjusted so that the amount of intake air is at its maximum in the engine speed range above approximately medium speed. A check valve is provided in the intake passage from the air cleaner that opens only in the direction from the air cleaner to the cylinders of the engine. A supercharger with a capacity matching the amount of intake air is connected via a power transmission mechanism, the discharge port of the supercharger is connected to the intake passage downstream of the check valve, and the power transmission mechanism //i Turn on power transmission when the engine's synchronous rotation is below or above approximately medium speed.
A supercharging device for an internal combustion engine, characterized in that it is provided with a means for turning off the supercharging device. (4) The supercharging device for an internal combustion engine according to claim 3, wherein the means for turning on or off the power transmission is operated by pressure downstream from the inverse ratio valve.