JPH02140424A - Internal combustion engine using commonly mechanical supercharger and exhaust gas turbosupercharger - Google Patents

Abstract

PURPOSE:To control the operation and stopping of a mechanical supercharger by setting the speed of an engine at which a magnetic clutch is disengaged when the engine speed is raised higher than that at which the magnetic clutch is engaged when the engine speed is lowered. CONSTITUTION:A mechanical supercharger 21 is provided in mid course of an air supply passage 20, the one end of which is connected to a blower 16 of an exhaust gas turbosupercharger 13 and the other end is opened to the atmosphere. A belt 22 is provided to transmit power from the output shaft 23 of an engine body 10 to a mechanical supercharger 21, and a magnetic clutch 25 is provided to connect power to a power transmitting mechanism when the engine speed is at low and middle ranges and disconnect power from the engine when the engine speed is at high range. The speed of the engine at which the magnetic clutch 25 is disengaged when the engine speed is raised is set higher than that at which the magnetic clutch 25 is engaged when the engine speed is lowered. By this, frequent engagement and disengagement of the magnetic clutch 25 can be avoided even when the engine is operated near the engagement and disengagement speed zone. Thus, the supercharger can be operated smoothly since supercharging pressure is not fluctuated.

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to an internal combustion engine that uses both a so-called hybrid mechanical supercharger and an exhaust turbo supercharger.

(Prior art and its problems) As is well known, a mechanical supercharger called a supercharger has a high supercharging capacity in a low speed range, and an exhaust turbo supercharger has a high supercharging capacity in a high speed range. is high.

When using an internal combustion engine as a main marine engine for driving a screw, it is effective to use both of the above-mentioned superchargers in combination in terms of low-speed navigation in ports and the frequency of forward and reverse switching.

In the field of this type of combination engine, a prior art in which the operation of a mechanical supercharger is controlled by an electromagnetic clutch is already known, for example, in Japanese Patent Laid-Open No. 149521/1983.

However, the operation of the mechanical supercharger is controlled by an electromagnetic clutch.
In the case of N-OP P control, if the engine is operated in an intermittent rotation speed range where the electromagnetic clutch is disconnected and connected, the mechanical supercharger will repeatedly start and stop, causing so-called chattering. And it's not desirable.

(Object of the Invention) The present invention provides a so-called hybrid supercharged engine that uses both a mechanical supercharger and an exhaust turbo supercharger, which can smoothly control the operation and stop of the mechanical supercharger in the intermittent range of the electromagnetic clutch. The aim is to provide an internal combustion engine that

(Structure of the Invention) (1) Technical Means The present invention provides an exhaust turbo supercharger between an exhaust system and an air intake system of an internal combustion engine, one end of which is connected to a blower of the exhaust turbo supercharger, and the other end of which is connected to a blower of the exhaust turbo supercharger. A mechanical supercharger is installed in the middle of the air supply passage that opens to the atmosphere, and a power transmission mechanism is installed that transmits power to the output shaft of the internal combustion engine and the mechanical turbocharger. An electromagnetic clutch is provided that connects to transmit power and opens to cut off power transmission in a high-speed range, and the rotation speed at which the electromagnetic clutch is released when the rotation speed increases in the intermittent rotation speed range of this electromagnetic clutch is determined by This internal combustion engine uses both a mechanical supercharger and an exhaust turbo supercharger, and is characterized in that the rotation speed is set higher than the rotation speed at which the electromagnetic clutch is connected when the rotation speed decreases.

(2) The mechanical supercharger operates by setting the rotation speed at which the electromagnetic clutch is opened when the operating rotation speed increases to be higher than the rotation speed at which the electromagnetic clutch is engaged when the rotation speed decreases.
Make the stop smooth.

(Embodiment) FIG. 1 shows a case in which the present invention is applied to a marine diesel engine, particularly a marine main engine for driving a ship's screw, and 10 is a diesel engine main body. Exhaust system 11 of engine body 10
An exhaust turbo supercharger 13 is provided between the air supply system 12 and the air supply system 12 . An exhaust pipe 15 is connected to the turbine 14 of the exhaust turbo supercharger 13 . An air supply pipe 17 is connected to the blower 16, and an intercooler 18 is interposed in the middle of the air supply pipe 17.

One end of an air supply passage 20 is connected to the blower 16, and the other end of the air supply passage 20 is open to the atmosphere. A roots-type mechanical supercharger 21 (supercharger) is provided in the middle of the air supply passage 20. The mechanical supercharger 21 includes, for example, a belt 22
Power is extracted from the output shaft 23 of the engine body 10 using a power transmission mechanism (power transmission mechanism) or the like. An electromagnetic clutch 25 is interposed on the pulley 24 on the output shaft 23 side. Therefore, when the electromagnetic clutch 25 is disengaged, the belt 22 does not rotate, thereby extending the life of the belt 22. Other gear trains, chains, etc. may be used instead of Bell I/22.

A bypass passage 26 that bypasses the mechanical supercharger 21 is connected to the air supply passage 20, and a control valve 27 is interposed in the middle of the bypass passage 26.

The control valve 27 has a structure in which a check valve 28 and a relief valve 29 are integrated. When the mechanical supercharger 21 is stopped, the check valve 28 is opened to supply atmospheric air to the blower 16 through the bypass passage 26 that bypasses the mechanical supercharger 21, and the mechanical supercharger 21 is activated. Check valve 2 when
8 is closed, and when the amount of supercharging air in the mechanical supercharger 21 is too large, a relief valve 29 is opened to release a part of the supercharging air to the upstream side of the bypass passage 26. There is.

In FIG. 2 showing a control device for the electromagnetic clutch 25, reference numeral 30
is a rotation sensor that detects the rotation speed of the output shaft 23 in a non-contact manner. A detection signal 31 from the rotation sensor 30 is input to a controller 32, and after being processed by the controller 32, a control signal 33 is output from the controller 2 to the electromagnetic clutch 25. The control signal 33 is designed to control the electromagnetic clutch 25 on and off at, for example, a rotation speed of about 70% of the rated speed, as shown in FIG. 3, which will be described in detail later.

In Figure 3, which shows the engine speed N - applied voltage of the electromagnetic clutch, the intermittent speed range 35 where the electromagnetic clutch 25 switches from 0N to 0[')' is between N1 at idle and N2 at rated. The rating is set to approximately 70%.

In this intermittent rotation speed range 35, when the rotation speed N increases, N
4 switches from ON to OFF, and when the rotation speed N decreases, N3, which is lower than N4, switches from OFF to ON.
It is now switched to .

Therefore, with hysteresis control as shown in FIG. 3, even when the engine is operated in the vicinity of the intermittent rotation speed range 35, the mechanical supercharger 21 is not activated and stopped as frequently as in the past, and the engine is operated. The condition becomes stable.

In Fig. 4, which is a graph of rotation speed N - average effective pressure Pc (shaft torque T) plotting the practical exhaust concentration, when only the exhaust turbo supercharger 13 is operated, the characteristic
If the engine is operated with Pe raised above the above level, the exhaust smoke will become too thick, which poses a practical problem.

On the other hand, in the combined operation range where the mechanical supercharger 21 of N1 to 0.7XN2 and the exhaust turbo supercharger 13 operate, the amount of air supply increases due to supercharging by the mechanical supercharger 21, so that the characteristic X2
Even if the output is increased to , the exhaust smoke remains at the same level as characteristic X1.

By operating the mechanical supercharger 21, the range in which the system can be operated with clean exhaust air is expanded by the range R.

Next, details of the power take-off section to the mechanical supercharger 21 will be explained. Conventionally, as shown in FIG. 5, a mechanical supercharger 21
Since the electromagnetic clutch 25 is provided on the side, the belt 22 constantly rotates. On the other hand, in the case of the present invention, as shown in FIG. 6, the electromagnetic clutch 25 is provided on the pulley 24 on the engine body 10 side, and 41 on the mechanical supercharger 21 side is directly connected, so the electromagnetic clutch 25 is disconnected. In this case, the belt 22 does not rotate, and the life of the belt 22 is long.

Furthermore, as shown in FIG. 7, the conventional gear train that drives the pulley 24 on the engine main body 10 side includes a crank gear 42 fixed to the output shaft 23 (FIG. 1), a pump gear 43, and an idle gear. 44 meshes, idle gear 4
4 meshes with a fuel pump gear 45 for driving the fuel pump and a cam gear 46 for intake and exhaust valves, and a seawater pump gear 47 meshes with the cam gear 46.

In this conventional gear train, a pulley 24 (FIG. 5) is provided at the end of the output shaft 23, and the belt 22 is connected to the pulley 40.
However, when the explosive force of the combustion chamber is generated, an upward reaction force is applied to the end of the output shaft 23. Due to this reaction force, the belt 22 which takes out power to the pulley 40 is not preferably placed in a position where the upward external force increases due to the strength of the output shaft 23. Therefore, the arrangement of the belt 22 and the pulley 40 is limited to so-called horizontal pulling that extends in the lateral direction, and there is a restriction in the direction of power extraction.

Therefore, in the present invention, as shown in FIG.
A drive gear 48 for an electromagnetic clutch that meshes with the drive gear 48 is provided, and power is extracted from the drive gear 48. As shown in FIG. 9, the drive gear 48 is fixed to a cylinder block 49 of the engine body 10 and a support 52 that is pivotally supported by a gear case 50. As shown in FIG. A pulley 24 is rotatably supported on the right end of the shaft 52, and an electromagnetic clutch 25 is provided between the pulley 24 and the shaft 52.

Therefore, no matter what direction the belt 22 is placed, no external force due to the belt drive acts on the output shaft 23 (FIG. 8), and the strength of the output shaft 23 is not adversely affected. In addition, drive gear 4
Since the number of teeth of 8 can be set to increase the speed with respect to the output shaft 23, the rotation speed of the mechanical supercharger 21 increases.

(Effects of the Invention) As explained above, in the internal combustion engine that uses both the mechanical supercharger and the exhaust turbo supercharger according to the present invention, the mechanical supercharger 21
The electromagnetic clutch 25 that controls the operation and stopping of the
As shown in the figure, within the intermittent rotational speed range 35, the rotational speed at which the electromagnetic clutch is opened when the rotational speed increases is set higher than the rotational speed at which the electromagnetic clutch is engaged when the rotational speed decreases. Even when operating in a rotation range near the intermittent rotation speed range 35, fluctuations in supercharging pressure due to frequent activation/stop switching of the electromagnetic clutch 25 do not occur, and the supercharged engine can operate smoothly.

[Brief explanation of the drawing]

Fig. 1 is a schematic structural diagram of a supercharged engine that adopts the present invention, Fig. 2 is a structural schematic diagram showing the control system of the electromagnetic clutch, Fig. 3 is a graph of engine rotation speed vs. applied voltage, and Fig. 4 is a graph of engine rotation speed. -A graph of average a dynamic pressure, Fig. 5 is a schematic diagram of the structure of a conventional belt drive, Fig. 6 is a schematic diagram of the structure of the belt drive of the present invention, Fig. 7 is a schematic diagram of the structure of a conventional gear train, and Fig. 8 is a schematic diagram of the structure of the belt drive of the present invention. FIG. 9 is a schematic diagram of the structure of the gear train of the present invention, which is a schematic view taken along A-A 11 of FIG. 8. 10... Engine body, 11... Exhaust system,
]2... Air supply system, 13... Exhaust turbo supercharger, 20
...Air supply passage, 21...Mechanical supercharger, 25...
Electromagnetic clutch patent applicant Yanmar Diesel Aji Co., Ltd. Representative Patent attorney Tadataka Hishin 1- ,' ,,,,,)
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Claims (1)

[Claims] An exhaust turbo supercharger is installed between the exhaust system and the air supply system of an internal combustion engine, and a mechanical supercharger is installed in the middle of the air supply passage, with one end connected to the blower of the exhaust turbo supercharger and the other end open to the atmosphere. set up a machine,
A power transmission mechanism is provided to transmit power to the output shaft of the internal combustion engine and the mechanical supercharger, and the system is connected to this power transmission mechanism to transmit power in the medium and low speed range, and to cut off power transmission in the high speed range. An electromagnetic clutch that opens is provided, and the rotation speed at which the electromagnetic clutch is opened when the rotation speed increases in the intermittent rotation speed range of the electromagnetic clutch is set higher than the rotation speed at which the electromagnetic clutch is connected when the rotation speed decreases. An internal combustion engine that uses both a mechanical supercharger and an exhaust turbo supercharger.