JP2007064134A - Blow-by gas suction reduction device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a means preventing a situation that it is difficult to stop an engine due to suction of blow-by gas when a blow-by gas suction reduction device is provided on an industrial engine. <P>SOLUTION: A flow passage change over valve V is installed in a blow-by gas duct 2 communicating from an inside of an engine main body to an intake air duct 1. Blow-by gas from the engine main body is changed over to the intake air duct 1 and an atmospheric air open duct 3 by operation of the flow passage change over valve V. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a blow-by gas intake reduction device for an internal combustion engine for an industrial machine including a construction machine, and more particularly to a blow-by gas intake reduction device having means for ensuring safety when an accident such as a fall of an installed industrial machine occurs.

  A technique for preventing air pollution by recirculating blowby gas that has flowed out of a combustion chamber of an internal combustion engine into a crankcase or the like into an intake system and burning it is known. In an internal combustion engine provided with such a blow-by gas intake reduction device, when a large amount of oil mist is contained in the blow-by gas, even if the fuel is shut off to stop the engine, it does not stop immediately, but enters the combustion chamber. There is a risk that the oil in the blow-by gas that has flowed in will burn and the engine will continue to run.

  In addition, industrial machinery including construction machinery, such as excavators, is relatively easy to fall over. At that time, the mounted engine is in a sideways or overturned state, and oil is sucked into the intake pipe from the blow-by gas line connected to the inside of the cylinder head. Even if the fuel is cut off, the oil that has flowed into the combustion chamber from the intake pipe continues to burn, and the engine may not be stopped safely. Furthermore, if the engine continues to rotate while being laid down or overturned, oil is not sucked into the lubrication system, which may cause serious trouble such as engine burn-in.

Therefore, as a technology for dealing with such problems, in a vehicular diesel engine, an intake system blow-by gas recirculation position is opened upstream of the intake throttle valve, and the throttle valve is closed to block intake and intake of blow-by gas. The technique to do is proposed (refer patent document 1).
In addition, as a means to prevent engine overrun due to blow-by gas intake, a rotation speed detector is provided, and when the detected rotation speed exceeds a predetermined rotation speed, the on-off valve provided in the intake passage is closed to stop the engine. (See Patent Document 2).

However, these techniques do not assume a case where a large amount of oil flows, such as a fall accident of the engine of the industrial machine.
From the viewpoint of safety measures against troubles that are relatively infrequent and have a high cost with a complicated configuration such as operating an intake shutter, etc., these technologies are not compatible with this. What is needed is a simple, low-cost and reliable operation.
Japanese Utility Model Publication No. 58-114807 JP-A-5-10156

  The present invention addresses the above-mentioned problems, and when an engine for an industrial machine is provided with a blow-by gas intake reduction device, at the time of a fall, the situation where it is difficult to stop the engine due to oil suction from the blow-by gas conduit does not occur. It aims to provide a means to do.

  According to the present invention, in the blow-by gas intake reduction device used for an internal combustion engine for industrial machinery, the flow switching means (V) is connected to the blow-by gas conduit (2) communicating with the intake conduit (1) from within the engine body. The flow of the blow-by gas (G) from the inside of the engine body can be switched to the intake pipe (1) and the open air pipe (3) by the operation of the flow path switching means (V). (First invention).

  The operating means for switching the flow path switching means (V) is a manual operation (second invention).

Alternatively, the operating means for switching the flow path switching means (V1) is the electromagnetic coil (7), and the operation is operated in conjunction with the engine key (9) (third invention).
The above operation is preferably configured such that blow-by gas communicates with the intake pipe (1) when the engine key (9) is turned on.

Alternatively, the operating means for switching the flow path switching means (V2) is a hydraulic piston (8) that operates with the oil pressure of the engine lubrication system (fourth invention).
Note that the above operation is preferably configured such that the blow-by gas communicates with the open air pipe (1) when the oil pressure of the engine lubrication system becomes a specified value or less.
Of course, a simple structure such as a diaphragm may be used regardless of the hydraulic piston.

According to the present invention having the above-described configuration, the following operational effects can be obtained.
(1) In the event of an accident such as a fall of an industrial machine, the operation of the flow path switching means stops the intake-air reduction of blow-by gas and switches to open air. Therefore, the operation is continued by sucking oil from the blow-by gas line. Can be stopped.
(2) The structure is simple, no special sensor is required, and the flow path switching means is small and simple provided in the blow-by gas line, unlike the throttle valve and shutter provided in the conventional intake system. It can be configured with anything.
(3) According to the hydraulic operation system (fourth invention), in the event of an accident such as a fall, the flow path switching can be operated due to a decrease in the hydraulic pressure, and a simple structure can be configured.

Embodiments of the present invention will be described below with reference to the accompanying drawings.
FIG. 1 is a schematic diagram illustrating a blow-by gas intake reduction device for an internal combustion engine E mounted on an industrial machine such as an excavator, according to the present invention.
In the drawing, a flow switching means V is interposed in the blow-by gas pipe 2 communicated with the inside of the cylinder head cover 10, and the tip thereof is between the air cleaner (not shown) of the intake pipe 1 and the cylinder head 11 (for example, The air release pipe 3 is branched from the flow path switching means V so that the blow-by gas G can be switched to either the return to the intake air A or the open air. Yes.

  That is, the blow-by gas G leaked from the combustion chamber rises from the crankcase C to the inside of the cylinder head cover 10 and reaches the flow path switching means V from the blow-by gas pipe 2 and is recirculated to the intake pipe 1 during normal operation. Alternatively, in the event of an accident such as a fall, the flow path is switched by an operating means to be described later to open to the atmosphere.

  FIG. 2 shows an embodiment of the flow path switching means. In the figure, the flow path branch valve V is provided with a blow-by gas inlet 5 a communicating with the head cover 10 in the valve body 5, an outlet 5 b communicating with the intake pipe 1, and an outlet 5 c leading to the atmosphere opening pipe 3. The valve 5v provided in the valve body 5 is configured to be able to switch between opening and closing of the outlet 5b to the intake pipe and the outlet 5c to open to the atmosphere by operating the manual lever 6.

  With the above configuration, in the normal operation state, the valve 5v of the flow path branch valve V is positioned on the right side of the figure, and the blow-by gas G from the cylinder head cover 10 is discharged from the inlet 5a of the flow path branch valve V. It exits to the outlet 5b, is recirculated into the intake pipe 1, enters the combustion chamber together with the intake air A, and burns. When an accident occurs such as when the engine is stopped or overturned, the manual lever 6 is pulled to close the outlet 5b with the valve 5v (the state shown in FIG. 2), and the outlet 5c is allowed to flow out to the atmosphere release pipe 3.

  Therefore, when an industrial machine equipped with an engine to which the present invention is applied, such as an excavator, has caused a fall accident due to rough terrain operation, the operation should continue by inhaling oil from the blow-by gas line even if the fuel is shut off. Even in such a situation, by operating the manual lever 6, the flow of the blow-by gas G can be switched to the open atmosphere 3, the intake of oil into the combustion chamber can be shut off, and the engine can be stopped.

Next, the embodiment shown in FIGS. 3 and 4 is different from the embodiment of FIG. 2 in the operation means of the flow path switching means. That is, the flow path branch valve V1 has a configuration in which the electromagnetic coil 7 is attached as an operating means to operate the valve 5v. The electromagnetic coil 7 is wired from the engine key 9, and when the engine key 9 is ON (FIG. 4), the valve 5v opens the intake pipe side outlet 5b and closes the atmosphere release side outlet 5c.
That is, since the key 9 is ON when the engine is operating, the blow-by gas G is always recirculated to the intake pipe 1. On the other hand, if the key 9 is turned OFF when an accident or abnormality occurs, the fuel is shut off as shown in FIG. Further, the blow-by gas G is also cut off from the intake pipe and released to the atmosphere and is not sucked into the engine, so that the engine is surely stopped.

  In the embodiment shown in FIGS. 5 and 6, a hydraulic operation means is used as the flow path switching means. In the figure, the piston 8b in the hydraulic cylinder 8a is connected to the valve 5v of the flow path branch valve V2, and the oil pressure P of the engine lubrication system is guided to one end (left side in the figure) of the piston 8b. The side is released to the atmospheric pressure p0 and is urged by a spring 8c in a direction to cancel the force due to the hydraulic pressure P.

Therefore, when the hydraulic pressure becomes a predetermined value or less, such as when the engine is stopped, the valve 5v closes the intake pipe side outlet 5b and opens the air release side outlet 5c by the urging force of the spring 8c. It is not recirculated to 1, but is opened to the atmosphere (FIG. 5).
During normal operation, the hydraulic pressure P overcomes the urging force of the spring 8c, the valve 5v closes the air release outlet 5c, and the blow-by gas G is returned to the intake pipe 1 from the outlet 5b (FIG. 6).

  Here, if an industrial machine equipped with such an engine causes an accident such as a fall and the oil in the oil sump is washed away, the suction pipe (K in FIG. 1) of the lubrication system is exposed from the oil level and the oil pressure decreases. Occurs, the branch valve V2 is switched to the atmosphere opening side 3, the suction of the blow-by gas G is stopped, and the engine is surely stopped. Of course, the blow-by gas G is also shut off in the case of an emergency stop due to detection of a decrease in hydraulic pressure not caused by an accident.

The schematic diagram explaining the blowby gas intake reduction apparatus of this invention. The schematic diagram which shows one Embodiment (manual type) of the flow-path switching means by this invention. The schematic diagram which shows the time of engine stop of other embodiment (electromagnetic coil action | operation type) of the flow-path switching means of this invention. The schematic diagram which shows the time of normal driving | operating of embodiment of FIG. The schematic diagram which shows the time of engine stop of further another embodiment (hydraulic piston action type) of the flow-path switching means of this invention. The schematic diagram which shows the time of normal driving | operating of embodiment of FIG.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 ... Intake pipe 2 ... Blow-by gas pipe 3 ... Atmospheric open pipe 5 ... Valve body 5a ... Blow-by gas inlet 5b ... Intake pipe side outlet 5c ... Atmospheric open side outlet 5v ... Valve 6 ... Manual lever 7 ... Electromagnetic coil switching valve actuation means 8 ... Hydraulic switching valve actuation means 9 ... Engine keys V, V1, V2 ... Flow path switching valve

Claims (4)

  In a blow-by gas intake reduction device used for an internal combustion engine for an industrial machine, a flow switching means is interposed in a blow-by gas conduit communicating with the intake conduit from the inside of the engine body, and the engine main body is activated by the operation of the flow switching means. A blow-by gas intake and reduction device characterized in that the blow-by gas from the inside can be switched between an intake pipe and an air-open pipe.   The blow-by gas intake reduction device according to claim 1, wherein the operation means for switching the flow path switching means is a manual operation.   2. The blow-by gas intake reduction device according to claim 1, wherein the operation means for switching the flow path switching means is an electromagnetic coil, and the operation is operated in conjunction with an engine key.   2. The blow-by gas intake reduction device according to claim 1, wherein the operation means for switching the flow path switching means is a hydraulic piston that is operated by an oil pressure of an engine lubrication system.

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