JPH0417768Y2 - - Google Patents

Description

[Detailed Description of the Invention] [Industrial Application Field] This invention relates to a blow-by device that guides blow-by gas to an intake passage in an engine that uses alcohol fuel containing alcohol in gasoline.

[Prior Art] Alcohol fuel is effective in saving petroleum resources, and various engines that use alcohol fuel are currently known (for example,
-Refer to Publication No. 106147).

Generally, in an engine, in order to prevent air pollution caused by blowby gas, the blowby gas is introduced into an intake passage and reburned by the engine. In this case, alcohol-fueled engines have problems based on the characteristics of alcohol fuel.

In other words, alcohol has a boiling point of 64℃,
When the temperature reaches this temperature while the engine is warming up, the alcohol in the blow-by gas evaporates all at once, and a large amount of this vaporized alcohol enters the intake passage, causing rapid fluctuations in the air-fuel ratio and causing engine malfunction. becomes.

[Purpose of the invention] This invention was made to achieve the above purpose, and by effectively removing the alcohol content from blow-by gas, it prevents fluctuations in the air-fuel ratio and stabilizes the engine. It is intended to.

[Structure of the invention] In order to achieve the above object, this invention has a structure in which a separator for cooling and separating alcohol from the blowby gas is provided in the blowby gas passage of an engine using alcohol fuel.

According to this configuration, the alcohol present in the blow-by gas as a gas is cooled by the separator and separated as a liquid from the blow-by gas. Therefore, even if the temperature of the blow-by gas exceeds the boiling point of alcohol during engine warm-up, vaporized alcohol will not enter the intake passage, thereby preventing engine malfunctions due to air-fuel ratio fluctuations.

[Example] Hereinafter, an example of this invention will be described based on the drawings.

FIG. 1 is a sectional view showing an embodiment of this invention, and FIG. 2 is an enlarged sectional view of the separator.

In the figure, 1 is a crank chamber formed by a crankcase 2 and an oil pan 3, 4 is a piston, 5 is a crankshaft, and 6 is a cylinder. 7 is a cylinder head, and this cylinder head 7
A rocker arm chamber 9 is formed by the rocker arm chamber 9 and the head cover 8 fixed to the upper part thereof.

The cylinder head 7 includes an inlet manifold 11 forming an intake passage 10 and an exhaust pipe 1.
2 is attached.

A carburetor 13 is connected to the inlet manifold 11, and an air cleaner 14 is connected to the carburetor 13.

The Rocker arm chamber 9 is provided with an oil separator 15 having a labyrinth structure, and the Rocker arm chamber 9 and the air cleaner 14 are communicated via a breather passage 20 via the oil separator 15.
Air A for ventilation is introduced into the Rocker arm chamber 9. In addition, the oil separator 1
5 to the Rocker arm chamber 9 and the intake passage 10.
are communicated with each other by a blow-by gas passage 21. A PCV valve P is disposed in the blow-by gas passage 21, and this valve P opens only the direction in which the blow-by gas B flows out from the rocker arm chamber 9.

The fuel tank 16 stores alcohol fuel, for example, fuel F in which 20% alcohol is mixed into gasoline, and this fuel F is sent to the carburetor 13 by a fuel pump 17 through a route to be described later.

The blow-by gas passage 21 is provided with a separator 22, which is a feature of this invention. As shown in FIG. 2, this separator 22 is provided with a maze 2 by a baffle plate 23 in order to separate oil D and fuel F in the blow-by gas B using the difference in specific gravity.
4, and a second separation chamber 25 for cooling and separating alcohol E in fuel F from gasoline.
A partition wall 28 with a through hole 27 is provided between the two chambers 25 and 26. Further, 29 is a cooling pipe with fins 30 arranged in a meandering manner in the second separation chamber 26, and the alcohol fuel F sent from the fuel tank 16 is introduced into the cooling pipe 29 as a cooling medium. It is used.

Oil D separated in the first separation chamber 25 is returned to the oil pan 3 through a return pipe 32 with a check valve 31, and alcohol E is liquefied and separated by cooling in the second separation chamber 26. , and is returned to the fuel tank 16 via the recovery pipe 33.

Note that 34 shown in FIG. 1 is a temperature increasing medium for maintaining a good vaporized state of the fuel in the inlet manifold 11, and the temperature increasing medium 33 includes:
For example, engine cooling water (approximately 80°C) is used.

In the above configuration, the blow-by gas B leaked from the combustion chamber 37 in FIG.
The blow-by gas B in the Rocker arm chamber 9 enters the Rocker arm chamber 9 through the Rocker arm chamber 9 through the oil separator 15, after which a certain amount of oil is separated.
When entering the blow-by gas passage 21 and passing through the blow-by gas passage 21, the oil D is first separated in the first separation chamber 25 of the separator 22 shown in FIG. 2 separation chamber 2
At step 6, alcohol E is liquefied and separated by cooling. The blow-by gas B from which the oil D and the alcohol E have been separated and removed is sent from the outlet 39 through the blow-by gas passage 21 to the intake passage 10 of FIG. 1, where it is combusted in the combustion chamber 37.

Here, the reason why the alcohol fuel F is passed through the cooling pipe 29 of the second separation chamber 26 as a cooling medium is as follows.
It is as follows. That is, alcohol has a large latent heat of vaporization, and a large amount of thermal energy is required to vaporize alcohol (liquid) in the carburetor 13. Therefore, by utilizing the magnitude of the latent heat of vaporization of alcohol, the alcohol vapor in the second separation chamber 26 is efficiently cooled, and the fuel tank 16 is
The alcohol fuel sent from the carburetor 13
The temperature is raised in the second separation chamber 26 before being fed into the carburetor 10, thereby facilitating vaporization in the carburetor 10.

[Effects of the invention] As explained above, according to this invention, since a separator for cooling and separating alcohol is provided in the blow-by gas passage, vaporized alcohol is prevented from being introduced into the intake passage. is prevented.
Therefore, even if the blow-by gas exceeds the boiling point of alcohol during engine warm-up, there is no risk that the vaporized alcohol will flow into the intake passage all at once and cause sudden changes in the air-fuel ratio.
Stable rotation of the engine is maintained.

[Brief explanation of the drawing]

FIG. 1 is a longitudinal sectional view showing an embodiment of this invention.
FIG. 2 is an enlarged sectional view of the separator. 10...Intake passage, 21...Blow-by gas passage, 22...Separator, 29...Cooling pipe.

Claims (1)

[Scope of utility model registration request] In a blow-by device equipped with a blow-by gas passage for guiding blow-by gas of an engine using alcohol fuel to an intake passage, a separator for cooling and separating alcohol from the blow-by gas is provided in the blow-by gas passage. Features a blow-by device for alcohol fuel engines.