JPH07127424A - Crankcase ventilation valve - Google Patents

Abstract

PURPOSE:To prevent the lowering of oil generated by such a state that the negative pressure of an intake manifold becomes large at the decelerating time of a vehicle and this negative pressure reaches the combustion chamber of an engine. CONSTITUTION:At the time of normal operation, blow-by gas flows as shown by arrow marks in (a) through the opening of a first valve 22 and a valve seat 26. At the idling time, the negative pressure of an intake manifold becomes large, so that the first valve 22 moves as shown in (b), and the opening area of the first valve becomes small. At the decelerating time of a vehicle where the intake manifold negative pressure becomes larger than that at the idling time, a second valve 21 is moved to the left against a spring 29 as shown in (c) so as to be opened. The blow-by gas thereby flows in large quantity to keep the intake manifold negative pressure appropriate, thus preventing the lowering of oil.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a crankcase ventilation valve used for blow-by gas recirculation of an internal combustion engine of an automobile.

[0002]

2. Description of the Related Art In automobiles, engine blow-by gas is re-burned without being released to the outside.

Therefore, the blow-by gas in the crankcase of the engine is returned to the intake manifold through the crankcase ventilation valve.

FIG. 2 shows an example of the structure of a conventional crankcase ventilation valve. The outer frame is divided into a body 1 made of a synthetic resin material and a case 3, and the valve 2 and the seat 6 are made of metal. Metal sheet 6
An engaging portion 6'protruding to the outside is formed in the seat, and the seat 6 is fixed to the outer frame by using the engaging portion as an engaging element. Four
Is a spring for urging the valve 2 to the right, and 5 is a cushion spring (Japanese Utility Model Publication No. 60-24894).

In the crankcase ventilation valve of FIG. 2, the left side of the body 1 in the figure is connected to a pipe connected to the intake pipe, and the right side of the case 3 is connected to the crankcase of the engine.

3 and 4, reference numeral 7 indicates the crankcase ventilation valve of FIG. 8 is an engine, 9
Is a pipe connecting the crankcase ventilation valve 7 and the intake manifold 10, 11 is a throttle valve, 12 is an air cleaner, and 13 is a pipe for introducing fresh air from the air cleaner to the crankcase of the engine 8.

During normal operation of the engine, the throttle valve 11 is open and the intake manifold negative pressure is small. Therefore, the valve 2 in FIG. The flow path area of the case ventilation valve 7 remains relatively large.

Therefore, as shown in FIG. 3, the crankcase ventilation valve 7 is driven by the engine 8 by the intake manifold negative pressure generated by the intake of the engine.
The blow-by gas in the crank case of No. 2 is guided into the intake manifold (arrow A). The arrow A indicates a mixture of blow-by gas (arrow B) and fresh air C in the crankcase. Intake manifold 10 as indicated by arrow A
The blow-by gas returned to is newly mixed with the fresh air arrow D, is sent to the combustion chamber of the engine, and is burned. The crankcase is thus constantly ventilated. Arrow E, F
Also shows the flow of fresh air. Arrow G indicates exhaust.

During vehicle deceleration, the throttle valve 11 is closed as shown in FIG. 4, and the intake manifold 10 is closed.
The negative pressure inside becomes large. Then, in the crankcase ventilation valve 7 of FIG. 2, the negative pressure causes the valve 2 to move to the left against the spring 4 and stop by hitting the cushion spring 5. And the flow path area becomes the minimum,
Reduce the flow rate of blow-by gas (arrow A). Therefore, the negative pressure in the intake manifold 10 becomes very large.

[0010]

SUMMARY OF THE INVENTION In the above conventional technique,
Crankcase ventilation valve 7 during vehicle deceleration
Since the flow passage area becomes smaller and the negative pressure in the intake manifold also increases the negative pressure in the combustion chamber, the oil that lubricates the engine valve is sucked into the combustion chamber H (oil down) and burns, There was a problem that oil was abnormally reduced as well as white smoke was blown from the exhaust pipe.

Therefore, an object of the present invention is to provide a crankcase ventilation valve which can solve these problems.

[0012]

In order to achieve the above object, the present invention is inserted between a crankcase of a vehicle engine and an intake manifold, and is operated by a negative pressure in the intake manifold during normal operation during idling. In a crank ventilation valve having a valve (22) whose opening area is smaller than that of the second valve, a second valve (21) having a larger opening area during deceleration of the vehicle that produces a negative pressure larger than that at idle, and the second valve. (21)
Is provided with a spring (29) for normally urging the valve in the closing direction.

[0013]

Since the intake manifold negative pressure is small during normal operation of the engine, the conventional valve (22) guides blow-by gas with a large opening area. When the engine is idle, the intake manifold negative pressure activates the valve (22) to reduce the opening area, reducing the blow-by gas returned to the intake manifold.

When the vehicle decelerates, an intake manifold negative pressure larger than that at the time of idling is generated, and this large negative pressure resists the spring (29) and the second valve (21).
Blow-by gas is made to flow by increasing the opening area of, and the rise of the negative pressure in the fuel chamber is suppressed.

[0015]

EXAMPLE In the example of FIG. 1, reference numeral 21 denotes an inner body which also serves as the second valve. A first valve 22 has a tapered left end in the drawing. An inner case 23 is fixed to the inner body 21 by sandwiching a first valve seat 26 between the left end of the inner case and the inner body 21.

Reference numeral 24 is a compression spring mounted between the first valve 22 and the first valve seat 26, and biases the first valve 22 in the opening direction (rightward in the drawing). Reference numeral 25 is a cushion spring housed in the inner body 21. Assembled parts composed of parts 21 to 26 are shown in FIG.
The structure is almost the same as that of the conventional ventilation valve described above.

Reference numeral 27 denotes an outer case, which is formed in a substantially cylindrical shape (cylindrical shape) as a whole, and has the reference numerals 21 to 26 inside thereof.
An assembly consisting of the above parts is stored. Reference numeral 28 denotes a cover fixed to the left end of the outer case 27, and a pipe connection portion 28a is integrally formed at the left end thereof. Reference numeral 29 is a compression spring that biases the inner body 21 that also serves as the second valve to the right, and is mounted between the cover 28 and the inner body 21.

A pipe connecting portion 27a is integrally formed at the right end of the outer case 27, and the pipe connecting portion 27a is connected to the crankcase of the engine by a pipe (not shown). The pipe connecting portion 28a of the cover 28 is connected to the intake manifold by a pipe (not shown).

In normal operation of the engine, as shown in FIG. 1 (a), the first valve 22 moves slightly to the left against the spring 24, and air containing blow-by gas from the crankcase is moved. The flow rate of is controlled. The arrow indicates the flow containing blow-by gas.

At the time of idling, the first valve 22 moves further leftward in the drawing and stops by hitting the cushion spring 25 as shown in FIG. 1 (b), and the minimum flow rate is obtained (the amount of blow-by gas generated is Because it is small, the flow rate is set to match it).

At this time, the inner body 21, which also serves as the second valve, is biased by the spring 29 and pressed against the second valve seat 27b formed at the inner shoulder of the outer turbo body 27. To act like this,
The biasing force of the spring 29 is set to be considerably larger than the biasing force of the spring 24.

When the vehicle is decelerated by applying a negative pressure more than during idling, as shown in FIG. 1C, the assembly composed of the parts 21 to 26 moves to the left against the spring 29. , The right end of the inner body 21 that also serves as the second valve opens apart from the second valve seat 27b, a large amount of blow-by gas temporarily flows, and the negative pressure in the intake manifold is prevented from becoming excessively large. Corrected to the proper pressure. In the figure, reference character G indicates the distance between the second valve (inner body) 21 and the second valve seat 27b when the assembly is moved.

In the above-described embodiment, FIG.
As shown in (b), when the vehicle is decelerated such that the opening area between the first valve 22 and the first valve seat 26 is minimized and the intake manifold negative pressure is larger than during idling, the assembly of the parts 21 to 26 is assembled. The entire product is further moved to the left as shown in FIG. 1C to open the space between the second valve (inner body) 21 and the second valve seat 27b. You may do like this.

That is, the shape of the first valve 22 is slightly changed so that the opening area between the first valve seat 26 and the first valve 22 becomes zero at the time of idling in FIG. 1B. The valve 22 is provided with a step (step) that abuts on the first valve seat. Then, the right end surface of the inner body 21, which also serves as the second valve, is not made to be a uniform flat surface,
Provide unevenness. By doing so, the air containing blow-by gas flows through the gap between the unevenness and the second valve seat 27b during idling. The second valve (inner body) 21 is closed by the second valve seat 27b during vehicle deceleration in which a negative pressure larger than the negative pressure at idle is generated.
From the left side to the left side, the opening area becomes larger.

By doing so, the same effect as in the case of the embodiment shown in FIGS. 1A and 1B can be achieved.

[0026]

Since the crankcase ventilation valve of the present invention is constructed as described above, the ventilation flow rate in the crankcase becomes large during deceleration of the vehicle during deceleration of the vehicle when the intake manifold negative pressure is larger than during idling. As a result of keeping the intake manifold negative pressure of
You can prevent the oil from falling.

[Brief description of drawings]

FIG. 1 is a vertical cross-sectional view of an embodiment of the present invention, in which (a) is a mode during normal operation of the engine, (b) is a mode during idling,
(C) is a mode during vehicle deceleration.

FIG. 2 is a vertical cross-sectional view of a conventional technique.

FIG. 3 is a schematic diagram of an intake and exhaust system of an engine having a blow-by gas recirculation system.

FIG. 4 is a schematic diagram of an intake / exhaust system of an engine having a blow-by gas recirculation device, and is a diagram illustrating a mode during vehicle deceleration.

[Explanation of symbols]

 21 Second Valve (Inner Body) 22 First Valve 24 Spring 27 Outer Case 27b Second Valve Seat 29 Spring

Claims (1)

[Claims] 1. A crankcase ventilation valve having a valve that is inserted between a crankcase of a vehicle engine and an intake manifold, operates by negative pressure of the intake manifold, and has a smaller opening area than during normal operation during idling. A crankcase ventilation characterized by comprising a second valve having a large opening area when the vehicle is decelerated, which produces a larger negative pressure than during idling, and a spring for constantly biasing the second valve in a closing direction. valve.