JPH0123654B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a supercharging device for an intake system of an internal combustion engine.

[Conventional technology and its problems]

It is widely known that supercharging is used as a means to improve output and reduce fuel consumption in internal combustion engines. Some are equipped with a supercharger that is rotationally driven by an internal combustion engine.

This supercharging method is called mechanical supercharging. In mechanical supercharging, the supercharger is rotationally driven by an internal combustion engine, so compared to exhaust turbo supercharging, the rotation speed is lower. It is effective for supercharging in the operating range of the internal combustion engine, and has advantages such as good acceleration response. Since the machine is quite large, it is not suitable for mounting on a vehicle, and there is also a problem with the durability of the supercharger in a high rotation speed operating range.

Therefore, Japanese Patent Application Laid-open No. 55-139929 as a prior art discloses that the intake path from the air cleaner to the intake manifold is composed of an intake pipe for the high rotation range and an intake pipe for the low rotation range. A supercharger that is rotationally driven by an internal combustion engine by rotating a supercharger installed in the intake pipe for a low rotational range only in an operating range of rotational speed lower than a certain rotational speed of the internal combustion engine. It is proposed to perform mechanical supercharging by only in the operating range where the rotation speed is lower than a certain rotation speed.

However, this device switches from a supercharging state to a non-supercharging state by stopping the rotational drive of the supercharger in the high rotation speed operating range of the internal combustion engine, thereby creating a non-supercharging state. Because the output of the internal combustion engine changes rapidly and greatly when switching from a non-supercharged state to a supercharged state,
Drivability deteriorates, and since there is no supercharging in the high rotation speed range,
The acceleration performance and fuel consumption rate were low in this high rotational speed operating range.

Moreover, in the prior art, an intake pipe for a low rotation range equipped with a supercharger is arranged in parallel with an intake pipe for a high rotation range, and the intake pipe for the low rotation range is The inlet end of the intake pipe for the low rotation range is connected to the intake pipe for the high rotation range at a location near the air cleaner, while the outlet end of the intake pipe for the low rotation range is connected to the intake pipe for the high rotation range. Since it is configured to connect near the manifold, the intake pipe for the low rotation range becomes extremely long, which not only results in an increase in size, but also increases intake resistance, which reduces the effect of supercharging. It was hot.

The present invention, like the prior art, combines mechanical supercharging with
In the case where the engine is only operated in a driving range where the rotational speed is lower than a certain rotational speed, it is possible to prevent deterioration of drivability without increasing the size or reducing mechanical supercharging, and to improve acceleration in a driving range where the rotational speed is high. The purpose is to improve performance and fuel consumption.

[Means for solving problems]

In order to achieve this object, the present invention provides an internal combustion engine with a supercharger that is rotationally driven by the internal combustion engine, and a surge tank that extends in the direction of the cylinder row in the internal combustion engine. The length of the intake path from the surge tank to the combustion chamber in each cylinder is determined by connecting the intake port in each cylinder with an independent branch intake pipe for each cylinder.
The amount of intake air is set to be maximum in the operating range of the internal combustion engine at a rotation speed higher than the approximately medium speed rotation speed, and a main intake pipe line from an air cleaner is connected to the surge tank, and the main intake pipe line is connected to the surge tank. In some cases, the amount of intake air is set to be maximum in the operating range of the internal combustion engine at a rotation speed higher than a predetermined rotation speed in the approximately medium speed rotation range, and a main intake pipe line from the air cleaner is connected to the surge tank. The main intake pipe is opened at a rotation speed higher than a predetermined rotation speed in a substantially medium speed rotation range of the internal combustion engine, and the main intake pipe is opened at a rotation speed higher than a predetermined rotation speed in a substantially medium speed rotation range of the internal combustion engine. A supercharging switching valve is provided that closes the main intake pipe in an operating range where the rotational speed is lower than the rotational speed, and the main intake pipe has a supercharging switching valve connected to the supercharger at a portion upstream of the supercharging switching valve. The suction pipe from the supercharger is connected to the intake pipe from the supercharger to the downstream side of the supercharging switching valve, and the power transmission mechanism from the internal combustion engine to the supercharger includes an internal combustion engine (abbreviation for internal combustion engine). The structure is such that a means is provided to cut off power transmission to the supercharger in an operating range where the rotational speed is higher than a predetermined rotational speed in the medium speed rotational range.

[Effect]

With this configuration, when the internal combustion engine is operating at a rotation speed lower than a predetermined rotation speed in an approximately medium speed rotation range, power transmission from the internal combustion engine to the supercharger is disabled.
When turned on, the supercharger is rotated and
By closing the supercharging switching valve in the main intake pipe,
Atmospheric air from the air cleaner reaches the supercharger,
After being compressed by the supercharger, it is sent to each cylinder via the main intake pipe, surge tank, and each branch intake pipe, so supercharging of the internal combustion engine is
This is done using a supercharger.

When the internal combustion engine reaches a rotational speed higher than a predetermined rotational speed in an approximately medium speed rotational range, the power transmission to the supercharger is cut off, the rotational drive of the supercharger is stopped, and the main The supercharging selector valve in the intake pipe opens, and the air cleaner and surge tank communicate directly through the main intake pipe.
Atmospheric air from the air cleaner is taken into each cylinder from the surge tank through each branch intake pipe. In this case, the length of the intake path from the surge tank to the combustion chamber in each cylinder is adjusted so that the amount of intake air is maximized in the operating range of the internal combustion engine at a rotation speed higher than the predetermined rotation speed in the approximately medium speed rotation range. With this setting, air is drawn into each cylinder from the surge tank using inertial supercharging.

In other words, supercharging of an internal combustion engine is performed by mechanical supercharging when the internal combustion engine is operating at a rotation speed lower than a predetermined rotation speed in the approximately medium speed rotation range. In the operating range, inertial supercharging can be performed with the rotational drive of the supercharger stopped.

〔Example〕

Hereinafter, an embodiment of the present invention will be explained with reference to the drawings (Fig. 1). In the drawing, reference numeral 1 indicates a multi-cylinder internal combustion engine, and reference numeral 2 indicates a positive displacement supercharger such as Roots, movable blade, or reciprocating type. The supercharger 2 is rotationally driven from the crankshaft 3 of the internal combustion engine 1 via a power transmission mechanism such as a belt 4, and the power transmission mechanism includes a hand,
An electromagnetic clutch 5 is provided to cut off power transmission to the supercharger 2 when the rotational speed of the internal combustion engine 1 becomes higher than a predetermined rotational speed in a substantially medium rotational speed range.

Reference numeral 6 indicates a surge tank disposed on the side of the internal combustion engine 1 so as to extend in the direction of the cylinder row. The cylinders are connected via independent branch intake pipes 8, and the opening of each branch intake pipe 8 into the surge tank 6 from the point where the intake port 7 of each cylinder opens into the combustion chamber of the cylinder. The length of the intake path up to
The length is set such that the amount of intake air is maximized in the operating range of the internal combustion engine 1 at a rotation speed higher than a predetermined rotation speed in a substantially medium speed rotation range.

Reference numeral 9 indicates an air cleaner, and the air cleaner 9 and the surge tank 6 are connected via a main intake pipe 10 having a relatively large diameter.
Inside, a supercharging switching valve 11 and a carburetor 13 with a throttle valve 12 are provided in series, and the intake passage 10 has an intake port for the supercharger 2 at an upstream side of the supercharging switching valve 11. The discharge pipes 15 of the supercharger 2 are connected to the pipe lines 14 and the discharge pipes 15 of the supercharger 2 to the downstream side of the supercharging switching valve 11, and the supercharging switching valve 11 is connected to the throttle valve 12 of the carburetor 13, When the opening of the valve 12 is below a certain degree, the supercharging switching valve 1
1 closes, and when the throttle valve 12 opens beyond a certain opening degree, the supercharging switching valve 11 opens in conjunction with this.

In the case of a fuel injection type internal combustion engine, as shown in FIG. 2, an air flow meter 16 is installed in the main intake pipe 10 on the upstream side of the supercharging switching valve 11, and an intake air amount control throttle valve is installed on the downstream side. 17, and the throttle valves 17 and the supercharging selector valve 11 in the main intake line 10 are associated in the same manner as in the embodiment shown in FIG.

In addition, in the case of a diesel engine, the supercharging switching valve 11 in the main intake pipe 10, as shown in FIG.
Fuel injection pump 18 in diesel engine 1'
related to the fuel injection amount control rod 19 or accelerator pedal, etc.

In such a configuration, the internal combustion engines 1, 1'
In the case of an operating range in which the rotation speed is lower than a predetermined rotation speed in a substantially medium speed rotation range, the supercharger 2 is operated by the electromagnetic clutch 5.
is turned on, and the supercharging switching valve 11 in the main intake pipe 10 closes, so that the intake air from the air cleaner 9 reaches the supercharger 2, where it is compressed, and then passes through the main intake pipe. The internal combustion engine 1, 1' is operated with so-called mechanical supercharging, since the air is sent to each cylinder via the intake line 10, the surge tank 6, and each branch intake line 8.

When the internal combustion engine 1, 1' reaches a rotational speed higher than a predetermined rotational speed in the approximately medium-speed rotational region, the electromagnetic clutch 5 is turned OFF to stop driving the supercharger 2, and the main intake pipe Since the supercharging switching valve 11 in 10 is opened, the intake air from the air cleaner 9 is directly introduced into the surge tank 6 without passing through the supercharger 2, and then is introduced into each cylinder from each branch intake pipe 8. be done. In this case, the length of the intake path from the surge tank 6 to the combustion chamber of each cylinder is set so that the intake air is at its maximum in the operating range where the engine speed is higher than the predetermined engine speed in the approximately medium speed engine speed range. As a result, the internal combustion engines 1, 1' experience so-called inertia overload in the operating range where the rotational speed is higher than the predetermined rotational speed in the approximately medium-speed rotational speed range, with the power transmission to the supercharger 2 being turned off. Operated with salary.

〔Effect of the invention〕

As described above, according to the present invention, the following effects are achieved.

Supercharging of the internal combustion engine is performed by mechanical supercharging in the operating range where the engine speed is lower than a predetermined rotation speed in the approximately medium speed rotation range of the internal combustion engine. In a high rotational speed range, inertia supercharging is performed with the rotational drive of the supercharger stopped.In other words, the internal combustion engine operates at a predetermined rotational speed in the approximately medium speed rotational range, and then Mechanical supercharging is used in low rotational speed operating ranges, and inertial supercharging is used in higher rotational speed operations, unlike the prior art that switches between mechanical supercharging and non-supercharging. Because there is no major change in output, drivability can be improved without significant fluctuations in output.Moreover, inertial supercharging is not required in the operating range where the engine speed is higher than the predetermined speed in the approximately medium speed range of the internal combustion engine. By doing so, it is possible to improve the acceleration performance and the fuel consumption rate in the operating range where the rotation speed is higher than the predetermined rotation speed in the substantially medium speed rotation range.

Inertial supercharging in an operating range of a rotation speed higher than a predetermined rotation speed in a substantially medium speed rotation range of an internal combustion engine is carried out using a surge tank extending in the direction of the cylinder row, and the surge tank and the intake port of each cylinder independently. By arranging this to be carried out through branch intake pipes connected to each other, the efficiency of inertial supercharging is high, and the intake air can be equally distributed to each cylinder, which further enhances the above-mentioned effects. be able to.

By configuring the connection of the suction pipe to the turbocharger and the discharge pipe from the turbocharger to the main intake pipe before and after the supercharging switching valve installed in the main intake pipe, these suction pipes Since the lengths of the pipe and the discharge pipe are shortened, it is possible to avoid an increase in size, and the intake resistance is reduced, so that the reduction in mechanical supercharging by the supercharger can be reduced.

[Brief explanation of drawings]

The drawings show embodiments of the present invention; FIG. 1 shows the first embodiment, FIG. 2 shows the second embodiment, and FIG. 3 shows the third embodiment. 1, 1'...Internal combustion engine, 2...Supercharger, 4...
Belt, 5... Electromagnetic clutch, 6... Surge tank, 8... Branch intake pipe, 9... Air cleaner, 1
0... Main intake pipe, 11... Supercharging switching valve, 14...
...Suction pipe line, 15...Discharge pipe line.

Claims (1)

[Claims] 1. An internal combustion engine is provided with a supercharger rotationally driven by the internal combustion engine and a surge tank extending in the direction of the cylinder row in the internal combustion engine, and the surge tank and the intake port of each cylinder are connected to each other. Each is connected with an independent branch intake pipe, and the length of the intake path from the surge tank to the combustion chamber in each cylinder is determined in the operating range where the engine speed is higher than the predetermined speed in the approximately medium speed speed range of the internal combustion engine. The intake air amount is set to be maximum at A supercharging switching valve that opens the main intake pipe in an operating range where the rotational speed is higher than a predetermined rotational speed, and closes the main intake pipe in an operating range where the rotational speed is lower than a predetermined rotational speed in a substantially medium speed rotational range of the internal combustion engine. The main intake pipe is provided with a suction pipe to the supercharger at an upstream side of the supercharging switching valve, and a discharge pipe from the supercharger at a downstream side of the supercharging switching valve. The power transmission mechanism from the internal combustion engine to the supercharger includes a power transmission mechanism for transmitting power to the supercharger in an operating range of the internal combustion engine at a rotation speed higher than a predetermined rotation speed in a substantially medium speed rotation range of the internal combustion engine. A supercharging device for an internal combustion engine, characterized in that it is provided with means for shutting off.