JP2785904B2 - Diesel engine stop device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a diesel engine for automatically stopping an engine when a lubricating oil level in an oil pan falls below a predetermined level to prevent a large engine damage such as seizure of the engine due to insufficient lubricating oil capacity. The present invention relates to improvement of an engine stop device.

[0002]

2. Description of the Related Art An oil level warning device for an internal combustion engine disclosed in Japanese Utility Model Publication No. 57-50483 has been proposed as a device for detecting a shortage of lubricating oil. This device operates when the tip of a pressure detecting tube immersed in lubricating oil of an oil pan detects a negative pressure in a crankcase due to a decrease in the level of lubricating oil. An electric signal is sent to the warning. However, this conventional technique cannot be applied to a small engine, such as a diesel engine for a small agricultural work machine, which does not have a battery and has no power generation device.

[0003] Therefore, as an engine stopping device applicable to a small diesel engine in which a battery and a power generation device are not mounted, an engine decompression device disclosed in Japanese Utility Model Laid-Open No. 1-152009 has been proposed. In this device, a latch portion is formed in a valve drive system that opens and closes a valve of an engine, while a lift-up rod that latches the latch portion and holds the lift-up state is orthogonal to the latch portion. Will be arranged. Then, when the tip of the pressure detecting tube immersed in the lubricating oil of the oil pan detects a negative pressure in the crankcase due to a decrease in the level of the lubricating oil, the actuator is actuated by this negative pressure and drives the lift-up rod, Forcibly open the valve via the valve drive system.

[0004]

SUMMARY OF THE INVENTION The above conventional example (Japanese Utility Model Laid-Open No. 1)
No. -152009), the lift-up rod incorporated in the diaphragm-type actuator is configured to forcibly open the valve, so the actuator must be mounted near the exhaust valve, the mounting position is restricted, and the design is free. There is no degree. Further, since the diaphragm-type actuator is mounted near the high-temperature exhaust muffler, the actuator is required to have heat resistance, and the cost is increased.

Accordingly, an object of the present invention is to provide an engine stop device which can be applied to a diesel engine having no battery and not having a power generation device, wherein the mounting position of the actuator can be freely set. To provide a stopping device. Another object of the present invention is to provide a diesel engine stopping device that does not require heat resistance by separating an actuator from a position of an exhaust muffler.

[0006]

SUMMARY OF THE INVENTION In order to achieve the above object, the present invention provides a method for detecting a negative pressure in a crankcase when a tip of a pressure detecting pipe immersed in lubricating oil of an oil pan detects a decrease in the level of lubricating oil. The negative pressure actuator drives the negative pressure actuator through the pressure detection tube, drives the transmission mechanism with the negative pressure actuator, and forcibly opens the exhaust valve with the transmission mechanism to stop the engine. The transmission mechanism includes a decompression pin and a spring for driving the exhaust valve in the opening direction, a decompression bar for reciprocating the decompression pin, and a stopper for locking the decompression bar for holding the decompression pin at the standby position. Further, it is desirable that the negative pressure actuator is a diaphragm type actuator and is disposed near the air cleaner and above the engine, and the transmission mechanism is preferably disposed near the exhaust valve.

[0007]

When a negative pressure in the crankcase is detected at the tip of the pressure detecting tube immersed in the lubricating oil of the oil pan due to a decrease in the level of the lubricating oil, the negative pressure drives the negative pressure actuator through the pressure detecting tube. The negative pressure actuator drives the stopper to release the decompression bar, and the decompression pin urged by the spring forcibly opens the exhaust valve to stop the engine.

[0008]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Embodiments of the present invention will be described below with reference to the accompanying drawings. The drawings should be viewed in the direction of reference numerals.
FIG. 1 is a conceptual diagram of a stop device for a diesel engine according to the present invention. The diesel engine stopping device 1 includes a pressure detection pipe 11, a one-way valve 15, an air vent 18, a negative pressure actuator 21, a transmission mechanism 30, and a valve mechanism 40 attached to the oil pan 3 of the diesel engine 2.
, And these configurations will be described in detail below.

An oil supply pump 7 is connected to a lower filter 6 in the oil pan 3, and lubricating oil is supplied from a pump to each bearing in the diesel engine 2 through a lubrication line 8. The pressure detection tube 11 will be described later (described with reference to FIG. 2). In the one-way valve 15, the valve body 16 is opened by the negative pressure detected by the pressure detection pipe 11.

The air vent 18 has a small-diameter orifice 19 therein, and when the one-way valve 15 is opened, a small amount of outside air is sucked to balance the pressure. The negative pressure actuator 21 is a diaphragm type actuator. The negative pressure when the one-way valve 15 is opened causes the rubber diaphragm 22 to be displaced by the negative pressure and pulls the drive rod 23.

The transmission mechanism 30 includes an exhaust valve 44 described later.
Is forcibly opened to stop the engine.

The transmission mechanism 30 includes a decompression pin 31 and a spring 32 for driving the exhaust valve 44 in the opening direction.
A decompression bar 33 for reciprocating the decompression pin, and a stopper 34 for locking the decompression bar to hold the decompression pin at the standby position.
As will be described later in detail, the rocker arm 42 is pressed by the cam 31 a formed at the tip of the decompression pin 31 to open the exhaust valve 44.

The valve mechanism 40 of the diesel engine is
An overhead valve type valve operating mechanism drives a valve body 43 from a cam (not shown) via a tappet, a push rod 41 and a rocker arm 42 to drive an intake valve (not shown) and an exhaust valve 44.
Open and close. The exhaust valve 44 is provided in the cylinder head 45, and the exhaust port 46 is connected to the exhaust muffler 51 via the exhaust pipe 52.

FIG. 2 is a front view of the diesel engine according to the present invention. The oil pan 3 is provided with a pressure detecting tube 11 having a distal end 11a immersed in lubricating oil OL, and a proximal end thereof connected to a suction side (primary side) of a one-way valve 15 via a joint 12 and a conduit 13. Have been.
An air vent 18 and a negative pressure actuator 21 are connected to a secondary side of the one-way valve 15 by a conduit 25.

The one-way valve 15, the air vent 18 and the negative pressure actuator 21 are arranged near the air cleaner 54 on the opposite side of the exhaust muffler 51 and above the engine 2, and are attached to the engine by a support member 55. Therefore, the negative pressure actuator 21 is far from the position of the exhaust muffler 51 and is not exposed to high heat, so that heat resistance is not required. Further, since the negative pressure actuator 21 is located at a position considerably higher than the lubricating oil OL, the oil does not enter and there is no possibility of malfunction.

FIG. 3 is a plan view of the diesel engine according to the present invention, and shows a one-way valve 15 and an air vent 18.
And that the negative pressure actuator 21 is disposed substantially on the same plane near the corner of the air cleaner 54. In this figure, a valve arm chamber 1a is attached to an upper portion of a cylinder head (not shown) substantially in the vicinity of the center. The valve arm chamber 1a has an exhaust valve 44 opened and closed by a rocker arm 42, and a rocker arm 56. Valve 57
And are arranged.

The transmission mechanism 30 is disposed near the exhaust valve 44, and the decompression pin 31 is provided in the valve arm chamber 1a.
Are rotatably supported, and the stopper 34 is swingably supported.

FIG. 4 is an exploded perspective view of a main part of the transmission mechanism according to the present invention. The decompression pin 31 has a cam 3
1a is integrally formed, and the decompression bar 33 is fixed to the other end. A spring 32 composed of a torsion spring is wound around the decompression pin 31,
Are biased in the clockwise direction in this figure (this figure shows a state in which the decompressor 33 is tilted counterclockwise). The decompression bar 33 is formed with a notch groove 33a cut out in the longitudinal direction of the lever.

At a position adjacent to the decompression bar 33,
A stopper 34 formed by bending a plate material is disposed. The stopper 34 is supported by a support pin 35 so as to be swingable, and the swing direction is a direction orthogonal to the extending direction of the decompression pin 31. The stopper 34 has one end 34 a in the swinging direction connected to the drive rod 23 of the negative pressure actuator 21 (not shown), and the other end 34 b engaged with the notch groove 33 a of the decompression bar 33.

The operation of the diesel engine stop device having the above configuration will be described below. In FIG. 1, when a proper amount of the lubricating oil OL is accumulated in the oil pan 3, the tip 11a of the pressure detecting tube 11 is immersed in the lubricating oil. When the engine is operated, the piston moves up and down in the cylinder, so that a positive pressure and a negative pressure are generated alternately in the crankcase 4, and pressure fluctuations occur alternately.

Accordingly, the lubricating oil OL in the oil pan 3
Although this is also affected by pressure fluctuations, this lubricating oil considerably buffers, so that only a slight negative pressure is detected in the pressure detecting tube 11. In the one-way valve 15, the valve body 16 is slightly opened by the minute negative pressure. However, a small amount of outside air is sucked from the orifice 19 of the air vent 18.
Does not displace.

The decompression lever 33 of the transmission mechanism 30
Is turned counterclockwise against the urging force of the spring 32, and the notch groove 33 a is engaged with the stopper 34.
That is, the decompression pin 31 is held in a standby state. Accordingly, since the rocker arm 42 is not pressed by the cam 31a, the exhaust valve 44 normally operates to open and close, and the engine is operated.

Next, a case where the oil level of the lubricating oil OL is significantly reduced for some reason will be described. In FIG.
When the lubricating oil OL drops to the oil level LL indicated by the imaginary line, the tip 11a of the pressure detecting tube 11 is exposed from the oil level, and directly detects the pressure fluctuation occurring in the crankcase 4. Therefore, when the tip 11a of the pressure detecting tube 11 detects a negative pressure in the crankcase 4 due to a decrease in the level of the lubricating oil OL, the negative pressure is applied to the pressure detecting tube 11, the one-way valve 15
And act on the diaphragm 22 of the negative pressure actuator 21 to displace it.

For this reason, the diaphragm 22 pulls and drives the drive rod 23 as shown in FIG. At this time, since the engagement between the stopper 34 and the notch groove 33a is released, the decompression lever 33 is rotated by the urging force of the spring 32, and is inverted to the upper position in FIG. Therefore, since the rocker arm 42 is pressed by the cam 31a, the exhaust valve 43 is forcibly opened. For this reason, the engine is stopped because the gas is not compressed in the cylinder. In addition, the decompression lever 33 is inverted to the upper position to notify that the capacity of the lubricating oil is insufficient.

[0025]

As described above, according to the present invention, when the tip of the pressure detecting tube immersed in the lubricating oil of the oil pan detects a negative pressure in the crankcase due to a decrease in the level of the lubricating oil, the negative pressure is applied to this pressure. A negative pressure actuator is driven through a detection pipe, a transmission mechanism is driven by the negative pressure actuator, and the transmission mechanism is used to forcibly open an exhaust valve to stop the engine. A decompression pin and a spring for driving the valve in the opening direction, a decompression bar for reciprocating the decompression pin, and a stopper for locking the decompression bar for holding the decompression pin in a standby position, so that a battery is mounted. Engine stop that can be applied to diesel engines that do not have An apparatus, can be freely set the mounting position of the actuator by changing the length of such transmission mechanism, downsizing of the entire engine by appropriately disposed around the engine.

Further, since the negative pressure actuator is a diaphragm type actuator and is disposed near the low temperature air cleaner and the transmission mechanism is disposed near the exhaust valve, the actuator is away from the position of the high temperature exhaust muffler. In addition, it is possible to avoid thermal injury, and it is possible to prevent oil from penetrating into the actuator by being disposed above the engine. The device has a relatively simple configuration and can be downsized.

[Brief description of the drawings]

FIG. 1 is a conceptual diagram of a diesel engine stop device according to the present invention.

FIG. 2 is a front view of the diesel engine according to the present invention.

FIG. 3 is a plan view of the diesel engine according to the present invention.

FIG. 4 is an exploded perspective view of a main part of the transmission mechanism according to the present invention.

FIG. 5 is an explanatory diagram of the operation of the diesel engine stop device according to the present invention.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 ... Diesel engine stop device, 2 ... Diesel engine, 3 ... Oil pan, 4 ... Crankcase, 11 ...
Pressure detection tube, 11a ... tip, 15 ... one-way valve,
18 air vent 21 negative pressure actuator 22
Diaphragm, 30 ... transmission mechanism, 31 ... decomp pin,
32: spring, 33: decompression bar, 34: stopper, 40: valve mechanism, 44: exhaust valve, 51: exhaust muffler, 54: air cleaner.

──────────────────────────────────────────────────続 き Continuation of the front page (56) References JP-A 62-176414 (JP, U) JP-A 5-47313 (JP, U) (58) Fields surveyed (Int. Cl. ⁶ , DB name) F01M 11/12 F02D 13/08 F02D 17/00 F02D 17/04

Claims (2)

(57) [Claims] When an end of a pressure detecting pipe immersed in lubricating oil of an oil pan detects a negative pressure in a crankcase due to a decrease in the level of lubricating oil, the negative pressure is applied to a negative pressure actuator via a pressure detecting pipe. In the diesel engine stopping device that drives and drives the transmission mechanism with this negative pressure actuator, and forcibly opens the exhaust valve with this transmission mechanism to stop the engine, the transmission mechanism drives the exhaust valve in the opening direction. A decompression pin and a spring, a decompression bar for reciprocating the decompression pin, and a stopper for locking the decompression bar for holding the decompression pin at a standby position. The lever is released and the spring and biased decomp pin operate the exhaust valve. Diesel engine stop device characterized by opening. 2. When the tip of a pressure detecting pipe immersed in lubricating oil of an oil pan detects a negative pressure in a crankcase due to a decrease in the level of lubricating oil, the negative pressure is used to operate a negative pressure actuator via a pressure detecting pipe. In the diesel engine stopping device for driving and driving the transmission mechanism with the negative pressure actuator and forcibly opening the exhaust valve with the transmission mechanism to stop the engine, the negative pressure actuator is a diaphragm type actuator and is located near the air cleaner. And a transmission mechanism disposed near an exhaust valve, wherein the transmission mechanism is disposed near an exhaust valve.