JPH0111932Y2 - - Google Patents

Description

[Detailed Description of the Invention] This invention relates to a blow-by gas recirculation device that returns gas containing unburned components leaking from between the piston and cylinder of an engine to the combustion chamber while adjusting the internal pressure of the engine.

Conventionally, when blow-by gas generated in the crank chamber of an engine is recirculated to the engine intake path, various negative pressures are generated in the intake path depending on the operating conditions of the engine. When gas is returned to the intake path, the internal pressure of the engine changes in various ways, and when the negative pressure is large, the internal pressure of the engine drops too much, which increases the generation of blow-by gas and tends to cause deterioration of the seal part. There was a problem that when the internal pressure of the engine rose, oil would blow out from the filler cap, level gauge, or seal.

For this purpose, some devices are installed with a pressure regulating valve in the blow-by gas recirculation path, but in conventional devices of this type, a spring was placed on the atmospheric chamber side of the diaphragm, so the engine internal pressure was Since the pressure is mainly regulated on the positive pressure side, there is a risk of the oil blowing out as described above, and the adjustment of the internal pressure required by the engine is unsatisfactory.
In addition, if the water in the blow-by gas that adheres around the valves cools down when the engine is stopped and the valves freeze, the valves will remain closed when the engine is restarted, increasing the engine internal pressure and causing the aforementioned oil leak. Ta.

The purpose of this invention is to eliminate the drawbacks of the conventional blow-by gas recirculation device, to make it possible to always keep the engine internal pressure almost equal to atmospheric pressure from the side below atmospheric pressure, and to prevent oil from blowing out to the outside of the engine even when the device freezes. It is an object of the present invention to provide an excellent blow-by gas recirculation device that is free from fear.

The blowby gas recirculation device of this invention which achieves the above object connects the diaphragm chamber connected to the blowby gas take-off pipe to the blowby gas recirculation pipe via an opening and an orifice, and connects the diaphragm that opens and closes this opening to at least a large It is characterized by being energized by a spring that maintains the opening in an open state using atmospheric pressure.

Embodiments of this invention will be described below with reference to the drawings.

FIG. 1 is a side view of an engine main body showing the structure of an embodiment of the blow-by gas recirculation device of this invention. In this embodiment, blowby gas is taken out from a blowby gas outlet 1b provided in a crankcase 1a of an engine 1, and is returned to an intake pipe 2 via a diaphragm device 10. 3 is an intake manifold, and 4 is an oil pan.

FIG. 2 is a sectional view taken along the line A--A in FIG. 1, showing the configuration of the diaphragm device 10 of this invention.
The diaphragm device 10 of this invention is attached to a diaphragm device body 12 so that one side of the diaphragm 11 faces the atmosphere, and is biased from inside the body 12 toward the atmosphere by a spring 14. 15 is a spring holder. A diaphragm chamber 16 surrounded by the device body 12 and the diaphragm 11 communicates with a blowby gas outlet 1b provided in the crankcase 1a of the engine 1 as shown in FIG. 1 using a blowby gas outlet pipe 5.

Furthermore, an annular sealing protrusion 17 is provided at the center of the diaphragm 11 on the side of the diaphragm chamber 16, and an extension 6a of the blow-by gas recirculation pipe 6 is provided at the opposite lower part of the sealing protrusion 17 with a slight gap therebetween.
When the diaphragm 11 moves toward the diaphragm chamber 16 against the spring 14, the opening 16b in the diaphragm chamber 16 of the extension 6a opens.
is sealed by the seal protrusion 17. In this embodiment, the blow-by gas recirculation pipe 6 communicates with the intake pipe 2 as shown in FIG.

In addition to these configurations, this invention further includes an orifice 18 that communicates with the diaphragm chamber 16 in the extension 6a of the blow-by gas reflux pipe 6,
A part of the blowby gas flowing through the blowby gas take-off pipe 5 is made to directly flow into the blowby gas recirculation pipe 6. Further, in this embodiment, a cover 13 is provided entirely on the atmosphere side of the diaphragm 11 to cover the diaphragm 11, so as to prevent the diaphragm 11 from being damaged by objects entering from the outside. This cover 13 is provided with an atmospheric hole 13a communicating with the atmosphere and dimples on the diaphragm surface side so that the atmosphere is always uniformly applied to the diaphragm 11 surface.

In the blow-by gas recirculation device of this invention configured as described above, the internal pressure of the engine 1 is always maintained at atmospheric pressure by appropriately selecting the strength of the spring 14 that biases the diaphragm 11 of the diaphragm device 10 and the diameter of the orifice 18. The pressure can be made to substantially match atmospheric pressure from below. In other words, when the engine internal pressure becomes higher than atmospheric pressure, diaphragm 1
1 is away from the opening 6b in the diaphragm chamber 16 of the extension 6a of the blow-by gas return pipe, so the blow-by gas flows into the blow-by gas return pipe 6 from both this opening 6b and the orifice 18 and flows into the intake pipe 2. The internal pressure of the engine is maintained at a pressure value slightly lower than atmospheric pressure. Also,
When the intake pipe negative pressure is small, the diaphragm 11 closes or opens the opening 6b in the diaphragm chamber 16 of the extension part 6a due to the differential pressure between the intake pipe negative pressure and the engine internal pressure, so that the engine internal pressure is almost reduced to the negative pressure side. It operates to maintain atmospheric pressure.

Furthermore, when the negative pressure in the intake pipe increases, the diaphragm 11 completely seals the opening 6b with the seal protrusion 17, so the blow-by gas flows into the blow-by gas return pipe 6 only from the orifice 18. As a result, the engine internal pressure does not become a large negative pressure. With the blow-by gas recirculation device of this invention that operates as described above, the internal pressure of the engine is maintained close to atmospheric pressure on the negative pressure side, as shown in FIG.

Further, in this invention, when the engine is stopped, the diaphragm 11 of the diaphragm device 10 is connected to the opening 6.
b remains open, so even if the engine is stopped with water in the blow-by gas still attached and this water freezes when restarting the engine and the diaphragm 11 does not operate, the blow-by gas can flow to the intake pipe and the blow-by gas will remain open. The frozen water can be immediately melted by the heat of the gas, and the diaphragm device 10 can be returned to its normal state.

In this embodiment, the blow-by gas outlet is the crankcase, and the recirculation destination is the intake pipe, but the blow-by gas outlet and the recirculation destination are not limited to these.

As explained above, this invention connects the diaphragm chamber connected to the blow-by gas extraction pipe to the blow-by gas recirculation pipe through an opening and an orifice, and operates the diaphragm that opens and closes this opening to open and close the opening at at least atmospheric pressure. Because it is energized by a spring that maintains the open state, it is possible to maintain the engine internal pressure at approximately atmospheric pressure, slightly on the negative side of atmospheric pressure, thereby preventing large fluctuations in engine internal pressure and increasing blow-by gas generation. Although it can eliminate problems such as seal deterioration and oil blow-out, the diaphragm remains open while the engine is stopped, so blow-by gas can be removed while the engine is stopped. Even if the water freezes and the diaphragm does not operate, blow-by gas can still flow into the reflux pipe.

[Brief explanation of the drawing]

FIG. 1 is a side view of the engine body showing the configuration of an embodiment of the blow-by gas recirculation device of this invention, and FIG. Cross section, 3rd
The figure is a diagram showing the internal pressure characteristics of an engine using the blow-by gas recirculation device of this invention. DESCRIPTION OF SYMBOLS 1...Engine, 1b...Blowby gas outlet, 2...Intake pipe, 5...Blowby gas outlet pipe, 6...Blowby gas recirculation pipe, 6a...Extension part, 10...Diaphragm device, 11... Diaphragm, 13...cover, 14...spring, 16...
...Diaphragm chamber, 17...Seal protrusion, 18...
...orifice chair.

Claims (1)

[Scope of utility model registration request] A diaphragm chamber connected to the blow-by gas take-off pipe is connected to the blow-by gas return pipe through an opening and an orifice, and the diaphragm that opens and closes this opening is energized by a spring that maintains the opening in an open state at least at atmospheric pressure. A blow-by gas recirculation device.