JPS5842597Y2 - Engine fuel evaporative gas collection device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an evaporative gas collection device that prevents evaporative fuel and blow-by gas from an engine from being diffused into the atmosphere.

In the past, a canister was generally used as a means to collect evaporative gas from an engine, but this method required troublesome work such as replacing the activated carbon due to its performance deterioration. There were problems such as the pipes to be connected were complicated and it was difficult to adjust the negative pressure within each pipe.

A so-called cleaner storage type (method in which evaporative gas is directly guided into the air cleaner and stored in the air cleaner) that does not use a canister is also known, but if the air cleaner is filled with evaporative gas, it can easily leak into the atmosphere. Since it would spread, strict regulations could not be applied.

Furthermore, since blow-by gas also flows back into the intake pipe, these gases accumulate in the intake pipe, causing a significant change in the air-fuel ratio at the next start, making it difficult to start.

In this case, a bypass port is opened on the downstream side (outlet side) of the air cleaner, and a valve is installed to switch the passage leading to the bypass port and the air cleaner.The air cleaner is sealed up from the crankcase to the atmosphere of evaporated fuel and blow-by gas. This is characterized by preventing the air from diffusing into the engine, and improving the starting ratio by sucking in fresh air from the bypass port.

Examples of actual rights in this case will be explained below with reference to drawings.

In the engine, 1 is a cylinder head, 2 is a cylinder, and 3 is a crankcase. An intake pipe 4 connected to the cylinder head 1 is connected to a carburetor 5 and an air cleaner 6.

A normally closed main valve 7 connected to a Guyafram valve 9 operated by negative pressure in the intake pipe downstream of the carburetor 5 is provided on the inlet side of the air cleaner 6, and the air cleaner 6 and the cylinder head 1 are connected to the intake pipe. It is connected by a pipe 8 separate from the pipe 4.

A bypass port 10 is opened in the intake pipe 4 on the downstream side (outlet side) of the air cleaner 6, and a sub-salve 11 that opens and closes between the bypass port 10 and the outlet side passage of the air cleaner 6 is installed in the intake pipe 4. The setting is peaceful.

This sub-valve 11, together with a scooter valve 12 provided on the carburetor 5, is connected to a starter lever 13, which is an engine starting member.

The starter lever 13 is operated to supply the air-fuel mixture from a jet dedicated to the starter without passing it through the main jet only at the time of starting, and is returned to its original position after starting the engine.

The reference numeral 14 in FIG. 1 is an oil separator, which is connected between the downstream side of the carburetor 5 in the intake pipe 4 and the crankcase 3 through pipes 15 and 16°17. .

FIG. 2 shows details of the main valve 7 and sub-valve 11 which are provided in the intake pipe 4 with the air cleaner 6 interposed therebetween.

Now, when the engine is stopped, the main valve 7 closes the passage of the intake pipe 4, and the sub-valve 11 closes the bypass port 10 as shown by the broken line in the figure.

Therefore, the intake pipe 4, the inside of the air cleaner 6, and the crankcase are in a sealed state.

This allows evaporated fuel and blow-by gases to accumulate in these large-capacity enclosures and not diffuse into the atmosphere.

When the engine is stopped, the oil separator 1
The oil accumulated in 4 flows into the oil pan through pipes 16,17.

Next, when starting the engine, by first operating the starter lever 13, the sub-valve 11 opens the bypass port 10 to the atmosphere as shown by the solid line in the figure.

At this stage, the main valve 7 still closes the inlet of the air cleaner 6.

When the engine is started in this state, the engine sucks in fresh air from the bypass port 10, is supplied to the engine together with fuel from the starter pipe 12, ignites combustion, and starts the engine.

Since the main valve 7 is closed at this time, a large amount of evaporative gas and blow-by gas accumulated in the air cleaner 6 will not be sucked into the engine.

Therefore, the engine can be started easily.

When the engine starts, the scooter lever 13 is returned to its original position, so the sub-valve 11 closes the bypass port 10, and due to the intake pipe negative pressure generated in the intake pipe 4,
The diaphragm valve 9 will operate and the main valve 7 will open.

Therefore, when the engine is stopped, vaporized fuel or blow-by gas accumulated in the intake pipe 4 or air cleaner 6 is drawn into the cylinder 2 of the engine together with fresh air by opening the main valve 7.

In this way, when the engine is started, the evaporated fuel and the blow-vicus sealed in the cab ivy 5 are only sucked into the cylinder 2, and fresh air is drawn from the bypass port 10 side by the opening operation of the sub-valve 11. Since the suction is softened, a large amount of evaporated fuel and blow-by gas in the large-capacity air cleaner 6 is not sucked in, and therefore an overly rich mixture does not occur, resulting in good starting performance.

Note that the blow-by gas existing in the oil separator 14 flows into the cylinder 2 through the pipe 15 and the intake pipe 4 and is combusted, as in the conventional case.

On the other hand, at this time, air is sucked into the crankcase 3 from the air cleaner 6 through the pipe 8, as in the conventional case, so even if the blow-by gas flows in this way, the inside of the crankcase 3 is under negative pressure. It won't happen.

When the engine is stopped, blow-by gas passes through the pipe 8 and accumulates in the air cleaner 6.

As described above, in an engine in which evaporated fuel or blow-by gas is guided to the intake pipe downstream of the air cleaner, the intake pipe is connected to the air cleaner inlet side of the intake pipe connected to the cylinder head of the engine. In addition to providing a normally closed main valve that is opened by pressure, a bypass port is opened on the downstream side of the air cleaner, and a sub-valve is provided to switch open and close the flow path between the bypass port and the intake pipe downstream of the air cleaner. Since the sub-valve is operated so that the bypass port side opens only when the engine starting member is operated, it is possible to prevent vaporized fuel and blow-by gas from diffusing into the atmosphere without using a canister. There is an effect that can be done.

In addition, the evaporated fuel and blow-by gas accumulated in the air cleaner are not sucked in when the engine is started, so the conventional type sucked them all at once when starting, which worsened the starting ratio. Unlike this, there is no possibility of starting problems.

Since the main valve is operated by negative pressure in the engine's intake pipe, its opening and closing timing is suitable for collecting evaporated fuel and the like.

Furthermore, the present device has the advantage that it uses fewer pipes than conventional canisters and can be installed with a shorter length, reducing the overall volume.

[Brief explanation of the drawing]

FIG. 1 is a conceptual diagram of an engine equipped with the proposed device, and FIG. 2 is an enlarged view of the main parts of the proposed device. 1... Cylinder head, 2... Cylinder, 4... Intake pipe, 6... Air cleaner, 7... Main valve, 10... ...Bypass port, 11...Sub valve, 13...
...Starter lever.

Claims (1)

[Scope of utility model registration request] In an engine in which evaporated fuel or blow-by gas is guided to the intake pipe downstream of the air cleaner, the normally closed valve is opened by negative pressure in the intake pipe on the inlet side of the air cleaner in the intake pipe connected to the cylinder head of the engine. In addition to providing a type main valve, a bypass port is opened on the downstream side of the air cleaner, and a sub-valve is provided to switch open and close the flow path between the bypass port and the intake pipe downstream of the air cleaner, and the operation of the sub-valve is controlled by:
A fuel evaporative gas collection device characterized in that the bypass port side is operated to open only when an engine starting member is operated.