JP2008175129A - Crankcase ventilation device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a crankcase ventilation device capable of reducing the quantity of oil taken away by blow-by gas. <P>SOLUTION: The crankcase ventilation device 5 is applied in an internal combustion engine 1 mounted on a vehicle as a travel power source, and connects a suction air passage and a crankcase 2 of the internal combustion engine 1 via a separation chamber 7 capable of separating blow-by gas and oil mist contained in the same. The separation chamber 7 is provided with a ventilation port 8 for introducing blow-by gas to the suction air passage side, and is connected to the crankcase 2 via a lower output port 10 positioned below the ventilation port 8 and an upper output port 11 positioned above the same. A vacuum operation valve 12 opening the lower output port 11 when an oil level surface S of oil 100 in the crankcase 2 rises due to change of a travel condition of a vehicle and the lower output port 10 is blocked, and blocking the upper output port 11 when the lower output port 10 is opened is provided. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a crankcase ventilation device applied to an internal combustion engine mounted as a driving power source in a vehicle.

  As a crankcase ventilation device, an inlet is provided at the lower end of the breather chamber that separates blow-by gas and oil mist contained therein, and a bypass passage is provided above the inlet and connected to the cylinder block. Has been known in which blow-by gas is sucked into a breather chamber through a bypass passage when it is blocked by oil level fluctuation in the crankcase (Patent Document 1).

Japanese Patent No. 2685837

  In the breather chamber of this ventilator, a baffle plate for attaching oil mist is provided between the lower end and the upper end, and an outlet connected to the intake passage is provided at the upper end of the breather chamber. A bypass passage is always open near the exit. Therefore, even when the inlet provided at the lower end of the breather chamber is not closed, the blow-by gas bypasses the baffle plate and flows into the intake passage side through the bypass passage. The blow-by gas passing through the bypass passage flows into the intake passage with insufficient oil mist separation, so that the amount of oil taken away by the blow-by gas increases.

  Accordingly, an object of the present invention is to provide a crankcase ventilation device that can reduce the amount of oil taken away by blow-by gas.

  The crankcase ventilation device of the present invention is applied to an internal combustion engine mounted on a vehicle as a power source for traveling, and the crankcase of the internal combustion engine via a separation chamber capable of separating blowby gas and oil mist contained therein. A crankcase ventilation device for connecting an intake passage, wherein the separation chamber is provided with a ventilation port for guiding blow-by gas to the intake passage side, and a first intake located below the ventilation port. The crankcase is connected to the crankcase via an outlet and a second outlet located above the first outlet, and the oil level in the crankcase rises due to a change in the running state of the vehicle. A valve mechanism that opens the second outlet when the first outlet is closed and closes the second outlet when the first outlet is open. Preparation By Rukoto, to solve the problems described above (Claim 1).

  According to this ventilation device, when the oil level of the oil in the crankcase rises due to a change in the running state of the vehicle and the first outlet is closed, the valve mechanism is positioned above the first outlet. A second outlet is opened. Therefore, when the first outlet is blocked, the blow-by gas is guided to the intake passage through the second outlet and the increase in the negative pressure in the separation chamber is suppressed, so that the first outlet is blocked. The accompanying increase in the amount of oil taken away can be suppressed. Moreover, since the second outlet is closed when the first outlet is not blocked, the flow of blow-by gas from the second outlet to the intake passage is restricted. Therefore, the amount of oil taken away can be reduced as compared with the case where the second outlet is always open.

  There is no particular limitation on the configuration of the valve mechanism according to the present invention. For example, as a valve mechanism, an electromagnetically driven valve that can open and close the second outlet, and an operation of the electromagnetically driven valve so that the second outlet is closed when the first outlet is closed. A control device may be provided. Further, as the valve mechanism, there is a negative pressure operating valve capable of opening the second outlet by opening using the negative pressure generated in the separation chamber when the first outlet is closed. It may be provided (Claim 2). In the latter aspect, the second outlet can be opened by opening the valve using the negative pressure of the separation chamber accompanying the closing of the first outlet without relying on electrical control as in the former. There is an advantage that the valve mechanism can be realized with a simple configuration.

  The second outlet may be provided at a position higher than the upper limit of the change width of the oil level (Claim 3). This aspect can reliably prevent the first outlet and the second outlet from being simultaneously closed.

  As described above, according to the present invention, when the first outlet is closed, the blow-by gas is guided to the intake passage through the second outlet and the increase in the negative pressure in the separation chamber is suppressed. Therefore, it is possible to suppress an increase in the amount of oil taken away due to the blockage of the first outlet. Moreover, since the second outlet is closed when the first outlet is not blocked, the flow of blow-by gas from the second outlet to the intake passage is restricted, and oil is taken away. The amount can be reduced.

  FIG. 1 schematically shows a main part of an internal combustion engine to which a crankcase ventilation device of the present invention is applied. The internal combustion engine 1 is mounted on a vehicle (not shown) as a driving power source. The internal combustion engine 1 has a crankcase 2 that houses a crankshaft (not shown), and a crankcase 4 is formed in the crankcase 2 by a cylinder block lower part 3 and an oil pan (not shown). A predetermined amount of oil 100 is held in the crankcase 2. The internal combustion engine 1 is provided with a crankcase ventilation device 5 for discharging blowby gas in the crankcase 2 and introducing it into the intake passage. The crankcase ventilation device 5 has an oil mist separator 6 that separates blow-by gas and oil mist contained therein, and connects the crankcase 2 and the intake passage via a separation chamber 7 formed in the oil mist separator 6. To do. The separation chamber 7 is provided with a baffle plate (not shown), and is configured so that oil mist can be separated from blow-by gas by adhering oil mist to the baffle plate.

  The separation chamber 7 is provided with a ventilation port 8 for guiding the blow-by gas to the intake passage side, and a ventilation valve 9 capable of opening and closing the ventilation port 8 using negative pressure in the intake passage. In order to guide blow-by gas from the crankcase 2 to the separation chamber 7, the two outlets 10 and 11 communicating the crank chamber 4 and the separation chamber 7 are respectively provided with a difference in height. The separation chamber 7 is connected to the crankcase 2 through these outlets 10 and 11. The lower outlet 10 is located below the ventilation port 8. The upper outlet 11 is positioned above the lower outlet 10 and is provided at a position higher than the upper limit of the fluctuation range of the oil level S of the oil 100 in the crankcase 2. Therefore, even when the oil level S rises due to a change in the running state of the vehicle, the two outlets 10 and 11 are not blocked simultaneously. The upper outlet 11 is provided with a negative pressure operating valve 12 as a valve mechanism that opens and closes the upper outlet 11 using the negative pressure generated in the separation chamber 7.

  3 and 4 show an example of the negative pressure operating valve 12. 3 shows a state in which the upper outlet 11 is closed, and FIG. 4 shows a state in which the upper outlet 11 is opened. As shown in these drawings, the negative pressure operating valve 12 includes a valve housing 13 fixed to the crankcase 2 in a state of being inserted into the upper outlet 11, and an opening direction of the upper outlet 11 (see FIGS. 3 and 4). A valve body 14 provided in the valve housing 13 so as to be movable in the left-right direction, and a direction in which the valve body 14 is accommodated in the compressed state and the upper outlet 11 is closed (FIG. 3, 4 to the right of 4). The valve housing 13 is formed with an inlet 13a that opens to the crank chamber 4 side and an outlet 13b that opens to the separation chamber 7 side. The valve body 14 has an umbrella portion 14a formed so that the outlet 13b can be opened and closed, and a flange portion 14b that receives the compression reaction force of the valve spring 15 is formed on the opposite side of the umbrella portion 14a. As shown in FIG. 2, when the oil level S of the oil 100 becomes higher than the lower outlet 10 due to a change in the running state of the vehicle and the lower outlet 10 is blocked by the oil 100 as shown in FIG. 4 and the separation chamber 7 are adjusted so that the valve is opened by the differential pressure generated, that is, the valve body 14 is moved from the state shown in FIG. 3 to the state shown in FIG. When the negative pressure operation valve 12 is opened, the upper outlet 11 is opened, and blow-by gas flows from the inlet 13a of the valve housing 13 toward the outlet 13b as shown by the arrow in FIG.

  According to the above configuration, as shown in FIG. 1, when the lower outlet 10 is open because the oil level S of the oil 100 is lower than the lower outlet 10, the upper outlet 11 operates under negative pressure. The valve 12 is closed. Thereby, as shown by the arrow line in FIG. 1, the blow-by gas in the crankcase 2 is guided to the separation chamber 7 through the lower outlet 10, and after the oil mist is separated in the separation chamber 7, the intake passage is made through the ventilation port 8. Led to. On the other hand, as shown in FIG. 2, when the oil level S of the oil 100 becomes higher than the lower outlet 10 due to a change in the running state of the vehicle, and the lower outlet 10 is blocked by the oil 100, the upper outlet 11. Is opened by the negative pressure operating valve 12. Thereby, as shown by the arrow line in FIG. 2, the blow-by gas in the crankcase 2 is guided to the separation chamber 7 through the upper outlet 11 and then to the intake passage through the ventilation port 8. Therefore, when the lower outlet 10 is blocked, an increase in the negative pressure of the separation chamber 7 is suppressed, so that an increase in the amount of oil taken away due to the closing of the lower outlet 10 can be suppressed. Moreover, since the upper outlet 11 is closed when the lower outlet 10 is not blocked, the flow of blow-by gas from the upper outlet 11 into the intake passage is restricted. Therefore, the amount of oil taken away can be reduced as compared with the case where the upper outlet 11 is always open.

  However, the present invention is not limited to the above embodiments, and can be implemented in various forms within the scope of the gist of the present invention. The valve mechanism according to the present invention is not limited to the above-described form. For example, as shown in FIG. 5, the valve mechanism according to the present invention includes an electromagnetically driven valve 16 that can open and close the upper outlet 11, a level sensor 17 that can detect the position of the oil level S, and a position of the oil level S that is lower. A control device 18 that controls the electromagnetically driven valve 16 based on a signal from the level sensor 17 may be configured so that the upper outlet 11 is opened when the outlet 10 is closed. The control device 18 may be realized by an engine control unit (ECU) that is a computer that appropriately controls the operating state of the internal combustion engine 1, or may be realized by a device different from the ECU.

The figure which showed typically the principal part of the internal combustion engine to which the crankcase ventilation apparatus of this invention was applied. The figure which showed the state which the oil level went up and the downward take-out port was block | closed. The figure which showed an example of the negative pressure action valve and showed the state where the upper extraction opening was closed. The figure which showed an example of the negative pressure operation valve, and showed the state by which the upper extraction opening was opened. The figure which showed other embodiment of this invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Internal combustion engine 2 Crankcase 5 Crankcase ventilator 7 Separation chamber 8 Ventilation port 10 Lower outlet (1st outlet)
11 Upper outlet (second outlet)
12 Negative pressure valve (valve mechanism)
100 Oil S Oil level

Claims (3)

Crankcase ventilation that is applied to an internal combustion engine that is mounted on a vehicle as a driving power source, and that connects a crankcase of the internal combustion engine and an intake passage through a separation chamber capable of separating blowby gas and oil mist contained therein. A device,
The separation chamber is provided with a ventilation port for guiding blow-by gas to the intake passage side, and is positioned above the first extraction port and the first extraction port located below the ventilation port. Connected to the crankcase via a second outlet,
When the oil level in the crankcase rises due to a change in the running state of the vehicle and the first take-out port is closed, the second take-out port is opened and the first take-out port is opened. A crankcase ventilation apparatus comprising a valve mechanism for closing the second outlet when the outlet is open.   As the valve mechanism, there is provided a negative pressure operating valve capable of opening the second outlet by opening using the negative pressure generated in the separation chamber when the first outlet is closed. The crankcase ventilation device according to claim 1, wherein the ventilation device is a crankcase ventilation device.   The crankcase ventilation device according to claim 1 or 2, wherein the second outlet is provided at a position higher than an upper limit of a change width of the oil level.

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