JPH09195781A - Supercharger for engine - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a supercharger having two air intakes in parallel. SOLUTION: An air intake manifold 10 has a first intake tube 11 with a turbo charger 14, and a second intake tube 12 with a supercharger driven in connection with the revolution of the crank shaft 15 of the engine E. The air intake manifold 10 is formed by communicating air passed through an air filter 17 to an intake port 3 through the first intake tube 11 or the second intake tube 12 provided in parallel thereto. At the confluence section of the intake port 3 for the first intake tube 11 with the second intake tube 12 a transfer valve 18 is disposed for selecting either the first tube 11 or the second intake tube 12. When the engine rotates in high revolution zone, the transfer valve 18 is switched as shown in solid line in the figure and the air is charged by the turbo charger 14, while the engine rotates in low revolution zone, the transfer valve is switched as shown in dotted line in the figure to charge air by using the supercharger 16.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an engine supercharging device, and more particularly to an engine supercharging device using a turbocharger and a supercharger together.

[0002]

2. Description of the Related Art Generally, as a supercharger for an engine, a supercharger driven by rotation of a crankshaft and a turbocharger driven by energy of exhaust gas are known. Since it uses the turbocharger, there is a problem that the power loss of the engine occurs.On the other hand, the turbocharger has a low driving force because the exhaust gas energy is small at the time of starting the engine or at low speed operation, so that a sufficient supercharging pressure can be obtained. There is a problem that cannot be done.

To solve such a problem, for example, there is a method disclosed in JP-A-7-91267. FIG. 4 is a diagram showing a schematic configuration of the supercharger disclosed in Japanese Patent Laid-Open No. 7-91267. As shown in FIG. 4, a turbocharger 52 is provided on the upstream side of the air supply passage 51 of the engine E. The supercharger 5 is provided downstream of the charger 52 and upstream of the charge air cooling device 53 and the throttle valve 54.
5 are provided. The front and rear of the supercharger 55 are connected by a bypass path 56, and an opening / closing control valve 57 is provided in the bypass path 56.

When the engine E is operating at a low speed, the opening / closing control valve 57 of the bypass 56 is closed and the crankshaft 58 is closed.
The rotation of the supercharger 55 drives the supercharger 55 to supply air reliably, while the drive of the supercharger 55 is stopped during high-speed operation of the engine E, and the bypass path 56
The opening / closing control valve 57 is opened to supercharge only by the turbocharger 52.

[0005]

However, the above-mentioned conventional techniques have the following problems. Since the supercharger 52 and the turbocharger 55 are arranged in series, the total length of the air supply passage becomes long and the efficiency of supercharging decreases. When the engine E is operating at high speed, the influence of the supercharger 55 can be almost eliminated by using the bypass passage 57, but when the engine E is operating at low speed, the supercharger 5
5 acts via a turbocharger 52. That is,
During low speed operation of the engine E, the supercharging rate of the turbocharger 52 and the supercharging rate of the supercharger 55 are integrated,
As a result, it becomes difficult to adjust the supercharging pressure obtained at the air supply port of the engine E according to the engine characteristics.

[0006]

SUMMARY OF THE INVENTION An object of the present invention is to provide an engine supercharger capable of solving the above problems with a simple structure.

[0007]

According to a first aspect of the present invention, there is provided a turbocharger for an engine, which is interlocked with rotation of a crankshaft of the engine and a first air passage having a turbocharger. And a second air supply passage provided with a supercharger that is driven by the first air supply passage and a first air supply passage and a second air supply passage. A switching valve for switching between the air passage, an engine speed detecting means for detecting the engine speed, and a supercharger if the engine speed is within a predetermined low speed range based on the detected engine speed,
If the rotational speed is within a predetermined high speed range, the turbocharger is driven, and in response to the drive switching operation, control means for controlling the switching state to switch the communication state of the first air supply passage and the second air supply passage. It is characterized by having. An engine supercharging device according to a second aspect of the present invention is characterized in that, in addition to the above configuration, a turbocharger driving and releasing operation clutch device and a supercharger driving and releasing operation clutch device are provided. There is.

[0008]

According to the engine supercharging device of the present invention, the engine speed detecting means detects the engine speed, and the control device distributes them in parallel on the basis of the detected engine speed. Supercharging is performed by selecting either the first air supply passage or the second air supply passage provided. Specifically, if the detected engine speed is within a predetermined low speed range, the switching valve is operated so that the air supply port communicates with the outside through the second air supply passage provided with the supercharger. At the same time, drive the supercharger. If the detected engine speed is within a predetermined high speed range, the switching valve is operated so that the air supply port communicates with the outside through the first air supply passage in which the turbocharger is arranged. Drive the turbocharger.

With this structure, the supercharger can be supercharged in parallel in the low speed rotation range and the turbocharger can be supercharged in the high speed rotation range in parallel, and the length of the air supply passage can be increased. Can be shortened. Further, in the configuration in which the two air supply passages are provided in parallel without providing the switching valve, the air supercharged on one side escapes from the air supply passage on the other side, but the configuration according to claim 1 is adopted. As a result, this can be prevented and a practical supercharger can be provided. In addition, supercharger only supercharges in the low speed range and turbocharger only in the high speed range, so it is easy to set the required boost pressure according to the low speed range and the high speed range. There is an advantage that the supercharging characteristic can be easily adjusted according to.

According to the engine supercharging device of claim 2,
By providing a clutch device for driving and releasing the turbocharger and a clutch device for driving and releasing the supercharger, the above operation is automatically performed only by issuing a command from the control device to each clutch device. There is an advantage that the switching operation can be performed.

[0011]

BEST MODE FOR CARRYING OUT THE INVENTION Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings. FIG. 1 is a configuration diagram of an engine supercharging device according to a first embodiment of the present invention. In the present embodiment, a two-cycle diesel engine E is taken as an example of the engine E. In a diesel engine E shown in FIG. 1, a piston 2 is vertically slidably inserted into a cylinder 1, and an air supply port 3 and an exhaust port 4 are provided above the cylinder 1.
Is provided, the air supply valve 5 is provided in the air supply port 3, the exhaust valve 6 is provided in the exhaust port 4, the air supply passage 10 is provided in communication with the air supply port 3, and the exhaust passage 7 is provided in communication with the exhaust port 4. Is provided.

The air supply passage 10 has a first air supply passage 11 having a turbocharger 14 and a second air supply passage 12 having a supercharger 16 driven in association with the rotation of a crankshaft 15 of the engine E. have. The air supply passage 10 is the first air supply passage 1 in which the air that has passed through the air cleaner 17 is arranged in parallel.
It is configured by communicating with the air supply port 3 via the first or second air supply passage 12. First air supply passage 11 and second
A switching valve 18 for switching between the first air supply passage 11 and the second air supply passage 12 is arranged at a confluence portion of the air supply passage 12 on the air supply port 3 side. An air supply cooling device 8 for cooling the air supply and increasing the air supply density is provided between the merging portion and the air supply port 3.

The turbocharger 14 includes a control device 19
A turbo clutch device 23 that disconnects or connects the shaft 20a of the turbine 20 and the rotary shaft 21a of the blower 21 in response to a supercharge control signal from the turbo clutch device 23 is provided. The rotation of the turbine 20 provided in the exhaust passage 7 sucks the atmosphere in the first air supply passage 11 and sends the compressed air to the air supply port 3 as in the conventional turbocharger. The supercharger 16 employs a roots-type supercharger in which two eyebrow type rotors rotate in opposite directions in the case, and a supercharging control signal from a control device 19 causes a super clutch device 24 to operate the supercharger 16 and the crank. The connection state with the shaft 15 is configured to be released or connected.

Further, the crankshaft 15 has a rotation speed detector 2
5 is provided, and the engine speed is input to the control device 19. FIG. 2 is a flowchart showing an outline of supercharging control performed by the control device 19 of the supercharging device for the engine shown in FIG. The operation of the present supercharging device will be described based on this flowchart.

First, in step SP1, the engine speed detected by the speed detector 25 is input to the control device 19, and in step SP2 the supercharger 16 performs supercharging to determine whether it is in a mechanical supercharging speed range or a turbocharger. If it is determined that the detected rotation speed is within the mechanical supercharging rotation speed range, the super clutch device 24 is brought into the connected state in step SP3. This turns on the supercharger 16 and the turbo clutch device 2
3 is released, the turbocharger 14 is turned off, and the second air supply passage 12 is connected to the air supply port 3 and the first air supply passage 11 is disconnected from the air supply port 3 in step SP4. The valve 18 is operated to end the series of processes.

On the other hand, if it is determined in step SP2 that the rotational speed detected is in the turbocharging rotational speed range, the super clutch device 24 is turned off by turning off the super clutch device 24 in step SP3. The turbocharger 14 is turned on by connecting the turbo clutch device 23, and the step S
At P4, the switching valve 18 is operated so that the second air supply passage 12 is cut off from the air supply port 3 and the first air supply passage 11 is communicated with the air supply port 3, and the series of processes is ended.

The operation of this supercharging device will be further described with reference to FIG. FIG. 3 is a diagram showing the engine speed on the horizontal axis and the supply pressure on the vertical axis. As described above, sufficient turbocharging pressure cannot be obtained only by turbocharging in the low speed rotation range. Therefore, when it is in a predetermined low speed rotation range (mechanical supercharging speed range), a predetermined supercharging pressure is obtained only by the supercharger 16 and the switching speed Nc as a boundary is obtained.
In the above turbocharging speed range, the predetermined supercharging pressure is obtained only by supercharging the turbocharger 14.

The switching rotation speed Nc in FIG. 3 is selected so that the supercharging pressure by the supercharger 16 and the supercharging pressure by the turbocharger 14 are the same. In this case, the switching speed Nc can be appropriately changed depending on the use and characteristics of the engine used. That is, the reduction ratio of the supercharger 16 and the size, shape, and output of the turbine 20 of the turbocharger 14 are adjusted so that the engine speed and the rotational speed are relatively less likely to be affected by the switching. The supercharging pressure of the turbocharger 14 and the supercharging pressure of the supercharger 16 are set to be equal to each other at a rotational speed at which it is difficult to obtain.

Even if the supercharger 16 is actually turned on or the turbocharger 14 is turned on, the respective supply air pressures do not rise immediately, so the releasing and connecting operations of the clutch devices 23, 24 are carried out within the rising time of the supply air pressures. Switching operation is performed early with a margin. In FIG. 3, nt is the ON speed of the turbocharger when switching from the supercharger to the turbocharger, and ns is the ON speed of the supercharger when switching from the turbocharger to the supercharger.

The present invention is not limited to the above embodiment, and various design changes can be made without departing from the scope of the present invention. Hereinafter, such an embodiment will be described. (1) The configuration of the switching valve shown in FIG. 1 is a schematic configuration, and various conventionally known switching valves can be applied. (2) The turbocharger may be attached to not only the diesel engine but also the gasoline engine and the gas engine, but it is obvious that the invention can be applied to such an engine. (3) In the configuration shown in FIG. 1, the first air supply passage 11 and the second air supply passage 12 are joined together in front of the air cleaner 17, but the partition wall is formed in front of the air cleaner 17. It is also possible to form it so that the two air supply passages 11 and 12 do not merge.

[Brief description of the drawings]

FIG. 1 is a diagram showing a schematic configuration of a supercharging device for an engine according to a first embodiment of the present invention.

FIG. 2 is a flowchart for explaining the operation of one embodiment of the present invention.

FIG. 3 is a diagram for explaining the operation of the supercharging device for an engine of the present invention, in which the horizontal axis represents the rotation speed and the vertical axis represents the supercharging pressure.

FIG. 4 is a diagram showing a schematic configuration of a supercharging device disclosed in Japanese Patent Laid-Open No. 7-91267.

[Explanation of symbols]

3 ... Air supply port, 11 ... 1st air supply passage, 12 ... 2nd air supply passage, 14 ... Turbocharger, 15 ... Crankshaft, 16
... Supercharger, 18 ... Switching valve, 19 ... Control device,
23 ... Turbo clutch device, 24 ... Super clutch device, 25 ... Rotation speed detector, E ... Engine.

Claims (2)

[Claims] 1. A first air supply passage (11) having a turbocharger (14) and a crankshaft (1) of an engine (E).
5) The supercharger (1) driven by the rotation of
6) and a second air supply passage (12) and a first air supply passage (1)
The first air supply passage (11) and the second air supply passage (1) are arranged at the confluence of the air supply port (3) side of the first air supply passage (12) and the second air supply passage (12).
2), a switching valve (18), an engine speed detecting means (25) for detecting the engine speed, and a supercharger (16) if the engine speed is within a predetermined low speed range based on the detected engine speed. ) Is driven to drive the turbocharger (14) if the rotation speed is within a predetermined high speed range, and the first air supply passage (11) and the second air supply passage (12) are communicated in response to the drive switching operation. A supercharging device for an engine, comprising: a control means (19) for switching a state by a switching valve (18). 2. A clutch device (23) for driving and releasing the turbocharger (14) and a clutch device (24) for driving and releasing the supercharger (16).
The supercharger for the engine according to claim 1, further comprising: