JPH0216316A - Blow by gas return device for multi cylinder engine - Google Patents

Abstract

PURPOSE:To prevent the abnormal ascent of output, by arranging a constitution in which a blow by gas return opening is formed on the down stream side of the main passage of an air intake passage or at a part of plural branching off passages, and blow by gas is returned only to a cylinder chamber which is part of a plurality of cylinder chambers. CONSTITUTION:At a multi cylinder engine 1, an air cleaner 2 is connected to a plurality of cylinder chambers 7 through the main passage 4 of an air intake passage 3 and a plurality of branching off passages 5, and blow by gas within a crank case 10 is led into the air intake passage 3 through a blow by gas return passage 11, a blow by gas return opening 8. In this instance, the blow by gas return opening 8 is formed on the side of the lowest stream of the main passage 4, and arrangement is so made that blow by gas containing oil in a great quantity is supplied only to a cylinder chamber 7 which is a part of plural cylinder chamber 7. Also, a diaphragm valve 20 is provided at this return opening 8, and in the case of the cleaner element of the air cleaner 2 having been clogged, valve closing is made as the abnormal ascent of air intake negative pressure is detected, and the overrun of the engine is made to be prevented.

Description

[Detailed Description of the Invention] [Industrial Application Field] This invention relates to a blow-by gas recirculation device for a multi-cylinder engine;
In particular, it relates to closed types.

[Conventional technology]

As this type of blow-by gas recirculation device, the one shown in FIGS. 6 and 7, for example, proposed by the present applicant has been known (Japanese Utility Model Publication No. 10813/1983).

That is, the air cleaner 2 of the multi-cylinder engine 1 is communicated with a plurality of cylinder chambers 7 through a main passage 4 of an intake passage 3 and a plurality of branch passages 5. 8 is opened, and the crank chamber 10 is connected to the intake passage 3 via a blow-by gas recirculation passage 11 and a blow-by gas recirculation port 8 in this order.

The blow-by gas recirculation passage 11 includes a gas passage 12 communicating between the crank chamber and the inside of the head cover 13, a blazer device 14 disposed on the head cover 13, and an oil separator 16.
and a gas introduction pipe 17 that communicates between the oil separator 16 and the blow-by gas recirculation port 8. The oil mist is separated through the separator 16 in order, and then passed through the blow-by gas recirculation port 8.
It is configured to flow more upstream of the main passage 4, pass through each branch passage 5, 5, and return to each cylinder chamber 7, 7.... In the above figure, the reference numeral 18 indicates the oil separator 16.
An oil return pipe 36 is an exhaust pipe for returning the oil into the oil tank 35.

[Problem to be solved by the invention]

Generally, in the above-mentioned rose type blow-by gas recirculation device, problems such as an abnormal rise in intake negative pressure due to clogging of the cleaner element, abnormal occurrence of blow-by gas due to piston ring damage, or overfilling of engine oil, etc. Due to this, a large amount of oil may mix with the blow-by gas and be sucked into the cylinder chamber.

In such a case, there is a risk that the engine will overrun in the conventional example described above. This is due to the following reasons.

That is, since the blow-by gas reflux port 8 is provided at the most upstream side of the main passage 4, the blow-by gas containing a large amount of oil flows into the main passage 4 from the reflux port 8, and then passes through each branch passage 5... This is because the fuel is diverted to the respective cylinder chambers 7, and is then combusted.

Note that in order for the oil portion to be combusted as described above, it is necessary that there is some margin in the air-fuel ratio between the intake air and the fuel. In other words, in the conventional example described above, a large amount of engine oil is combusted as a result of being distributed and supplied to each cylinder chamber 7, resulting in an abnormal increase in output.

The present invention has been made in consideration of these circumstances, and its technical object is to prevent engine overrun during abnormal suction of oil in a closed type blow-by gas recirculation device.

[Means to solve the problem]

In order to solve the above problems, the present invention is configured as follows.

That is, in the conventional blow-by gas recirculation device described above, the blow-by gas recirculation port 8 is opened in the downstream side of the main passage 4 or in some branch passages of the plurality of branch passages 5, so that the blow-by gas in the crank chamber 10 can be recirculated by blow-by gas. Gas reflux passage 11
The blow-by gas is characterized in that it is configured to pass through the blow-by gas recirculation port 8 and some of the branch passages 5 in order, and to be recirculated to only some of the cylinder chambers of the plurality of cylinders 7.

[For production]

In the present invention, the blowby gas recirculation port 8 is provided downstream of the main passage 5 or in a part of the plurality of branch passages 5, so that the blowby gas containing a large amount of oil is The gas is sucked into only some cylinder chambers through the gas reflux port 8 and some branch passages.

In other words, in the present invention, the oil mist is supplied intensively to some cylinder chambers, so it cannot be sufficiently combusted due to lack of oxygen, and the output does not increase abnormally, so the engine does not overrun.

〔Example〕

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

FIG. 1 is a plan view of a multi-cylinder engine equipped with a blow-by gas recirculation device according to the present invention.

This blow-by gas recirculation device communicates an air cleaner 2 of a multi-cylinder engine 1 with a plurality of cylinder chambers 7 through a main passage 4 of an intake passage 3 and a plurality of branch passages 5. A blow-by gas recirculation port 8 is provided at the most downstream side of the blow-by gas recirculation port 8, a diaphragm valve 20 is provided in the blow-by gas recirculation port 8, and the crank chamber 10 is communicated with the intake passage 3 through the blow-by gas recirculation passage 11 and the blow-high gas recirculation port 8 in this order. However, the blow-by gas in the crank chamber 10 is configured to be refluxed to only one of the plurality of cylinders 7, 7, . . . .

The blow-by gas recirculation port 8 may be provided in the most downstream branch passage as shown in FIG. 2, or in one of the plurality of branch passages as shown in FIG. ~For an 8-cylinder engine, a hole may be made in some of the branch passages, and the throat block 9
The intake boat 6 inside is included in the branch passage 5.

The blow-by gas recirculation passage 11 is the same as that in the conventional example, and is given the same reference numeral as shown in FIGS. 6 and 7, and the explanation thereof will be omitted.

The diaphragm valve 20 is used to detect an abnormal increase in intake negative pressure and shut off the blow-by gas recirculation passage 11 when the cleaner element of the air cleaner 2 becomes clogged, and serves as a safety device to prevent engine overrun. Function.

FIG. 4 is a longitudinal sectional view showing an example of the diaphragm valve 20. This diaphragm valve 20 includes a cylinder body 21, a diaphragm 22, a valve body 24 that closes the gas port 23 by the diaphragm 22, a return spring 25, and a proximity switch 26 that detects that the valve body 24 has closed the gas port 23. When the intake negative pressure rises abnormally, the diaphragm 22 pushes down the valve body 24 against the return spring 25 to close the gas port 23, thereby blowing high gas containing a large amount of oil mist. This prevents the air from flowing into the intake passage 3. In addition, the code 27 is a proximity switch 26
The subject is embedded in the valve body 24. When the proximity switch 26 is activated, a warning indicator lamp (not shown) is turned on.

FIG. 5 is a longitudinal sectional view showing another embodiment of the diaphragm valve 20. In this embodiment, the valve body 24a is supported on the lower side of the valve support body 24b via a chattering prevention spring 28, and the warning color indicates that the indicator 30 is attached to the valve support body 24b.
The function as a safety device for preventing overrun is the same as that shown in FIG. 4, except that it is installed upright on the top of the screen and is configured to be visible through the display window 31.

〔Effect of the invention〕

According to the present invention, the blow-by gas recirculation port is provided on the downstream side of the main passage or in one of the plurality of branch passages, and the blow-by gas flows into one of the plurality of cylinder chambers. Even if blow-by gas containing a large amount of oil is inhaled, the oil will be concentratedly supplied to some cylinder chambers, and some of it will be combusted. Even so, the remaining part will not burn due to lack of oxygen, and there will be no abnormal increase in output, so there is no risk of the engine overrunning.

[Brief explanation of the drawing]

Figures 1 to 5 show embodiments of the present invention, with Figure 1 being a plan view of a multi-cylinder engine equipped with a blow-by gas recirculation device, and Figures 2 and 3 showing the arrangement of blow-by gas recirculation ports. 4 and 5 are longitudinal sectional views each illustrating a diaphragm valve, FIG. 6 is a view corresponding to FIG. 1 showing a conventional example, and FIG. 7 is a front view of the sleeping area. be. ■...Multi-cylinder engine, 2...Air cleaner, 3...Intake passage, 4...Main passage, 5...Branch passage, 7...Cylinder chamber, 8...Blow high gas recirculation port, 10...Crank chamber, 11...Blowby gas recirculation passage. Road. Figure 6 Figure 7

Claims (1)

[Claims] 1. The air cleaner 2 of the multi-cylinder engine 1 is communicated with each of the plurality of cylinder chambers 7 through the main passage 4 of the intake passage 3 and the plurality of branch passages 5, and blow-by gas is supplied to the intake passage 3. In a blow-by gas recirculation system for a multi-cylinder engine, in which a recirculation port 8 is opened and a crank chamber 10 is connected to an intake passage 3 via a blow-by gas recirculation passage 11 and a blow-by gas recirculation port 8 in this order, the downstream side of the main passage 4 Alternatively, by opening blow-by gas recirculation ports 8 in some of the plurality of branch passages 5, the blow-by gas in the crank chamber 10 is transferred to the blow-by gas recirculation passage 1.
1. A blow-by for a multi-cylinder engine characterized in that the blow-by gas is configured to pass through the blow-by gas recirculation port 8 and some of the branch passages 5 in order, and to be recirculated to only some of the cylinder chambers of each of the plurality of cylinders 7. gas reflux device