JPH029089Y2 - - Google Patents

Description

[Detailed description of the invention] This invention is formed in the intake system of an internal combustion engine, and when the opening of the carburetor throttle valve is below a predetermined opening, it is upstream of the throttle valve, and when the opening is above the predetermined opening, it is downstream of the throttle valve. A first negative pressure port and a second negative pressure port are provided in a passage for recirculating exhaust gas from the exhaust system to the intake system of the internal combustion engine, and the exhaust gas is introduced from the first negative pressure port via a negative pressure pipe. an exhaust gas recirculation valve that opens and closes due to negative pressure; an atmospheric pressure chamber defined by a diaphragm and communicating with the second negative pressure port and partially open to the atmosphere; a pressure chamber separated from the atmospheric pressure chamber and communicating the exhaust gas recirculation valve to the exhaust side; a negative pressure regulating valve controlling communication between the atmospheric pressure chamber and the negative pressure pipe by expansion and contraction of the diaphragm; The present invention relates to an evaporated fuel separation device for an internal combustion engine, which is equipped with a charcoal canister that adsorbs fuel.

In such a device, it is desired that a sufficient amount of detached fuel be supplied when necessary, and that the fuel be supplied in a manner that does not deteriorate the operating condition of the engine.

The present invention provides a device that enables a sufficient supply of detached fuel and also enables a supply mode that does not deteriorate operating performance.

Therefore, according to the present invention, the above-mentioned charcoal canister has an atmospheric space that is open to the atmosphere through a fuel adsorption layer that adsorbs fuel, and a first valve that has a control valve that opens and closes depending on the operating state of the engine. a fuel withdrawal space that communicates with the intake system of the engine through a passageway and a fuel withdrawal space that communicates with the atmospheric pressure chamber of the negative pressure regulating valve through a second passage; is open to the atmosphere via the second passage, the fuel separation space, the fuel adsorption layer, and the atmospheric space.

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

First of all, it is known as exhaust gas recirculation (hereinafter referred to as exhaust gas recirculation).
Let's start with the device (abbreviated as EGR).

EGR connects the exhaust pipe 2 and intake pipe 3 of the internal combustion engine 1 to recirculate exhaust gas from the exhaust system to the intake system.
The passage 4 is provided with an EGR valve 5. this
The EGR valve 5 includes a constant pressure chamber 7 connected to the exhaust pipe 2 via a throttle 6, a valve seat 8 provided to control the connection between this constant pressure chamber 7 and the intake pipe 3, and a valve that cooperates with the constant pressure chamber 7. The valve body 9 has a negative pressure operating mechanism 10 for operating the valve body 9. This operating mechanism 10
A negative pressure chamber 12 defined by a diaphragm 11 of
A spring 13 is provided therein which biases the diaphragm 11 and therefore the valve body 9 towards the valve seat 8 .
The negative pressure chamber 12 is located on the upstream side of the throttle valve 31 of the carburetor 30 through a negative pressure passage 15 having a throttle 18 when the opening is below a predetermined low opening and is on the downstream side when the opening is above this opening. Negative pressure outlet ports 32 and 33
The first negative pressure port 32 is one of the first negative pressure ports.

The negative pressure regulating valve 14 has a bleed pipe 17 that is connected to the downstream side of the throttle 18 of the negative pressure passage 15 and opens to the atmospheric pressure chamber 22, and the control valve body 20 that changes the opening area of the bleed pipe 17 is as follows: It is attached to a diaphragm 21 that partitions an atmospheric pressure chamber 22.
Pressure chamber 24 isolated by diaphragm 21
is connected to the EGR valve 5 through a passage 26 having a throttle 25.
It is connected to a constant pressure chamber 7. The atmospheric pressure chamber 22 is
Further, through a passage 28 having a throttle 27, the vaporizer 3
0 is connected to a negative pressure extraction port 33 serving as the second negative pressure port. Note that 29 is a spring that acts on the diaphragm 21 to separate the control valve body 20 from the bleed pipe 17.

A carbon canister 40 has an activated carbon layer 41 for adsorbing fuel vapor, and an adsorption passage 42 feeding into the activated carbon layer 41 communicates with the fuel evaporation space of the fuel tank 43. Activated carbon 4 in canister 40
An atmospheric space 44 on one end face of the valve 1 opens to the atmosphere through an opening 45, and a separation space 46 on the other end face opens to the atmosphere through a passage 47 serving as the second passage. It is connected to the atmospheric pressure chamber 22 and communicates with the intake pipe 3 via a passage 48 serving as the first passage. A throttle 49 is provided in the passage 48 near the intake pipe opening, and a control valve 50 is provided in the passage 48 to open and close the passage 48 depending on the operating conditions of the engine.

Now, when EGR is performed in engine 1,
That is, when the throttle valve opening degree of the carburetor 30 is equal to or higher than the predetermined value, the negative pressure take-off ports 32 and 33 are located downstream of the throttle valve 31, and the intake negative pressure is transferred to the passage 15.
is transmitted to the negative pressure chamber 12 of the EGR valve 5 via.
As a result, the diaphragm 11 of the operating mechanism 10 bends upward against the force of the spring 13, separating the valve body 9 from the valve seat 8, so that exhaust gas from the exhaust pipe 2 passes through the constant pressure chamber 7 and the valves 8 and 9. It is returned to the intake pipe 3.

When the amount of exhaust gas, that is, the amount of intake air to the engine is small, the pressure in the constant pressure chamber 7 and the pressure chamber 24 of the negative pressure regulating valve 14 connected to it via the passage 26 becomes low, and the diaphragm 21 and the control valve body 20 is moved downward by the spring 27,
The opening of the bleed pipe 17 is opened, and the atmospheric pressure from the atmospheric pressure chamber 22 is transferred to the bleed pipe 17 and the passage 15.
is supplied to the negative pressure chamber 12 of the EGR valve 5 via
Since the diaphragm 11 is pushed downward and the valve body 9 is pressed against the valve seat 8, the valves 8 and 9 are closed.
Stop EGR.

Now, according to the present invention, the charcoal canister 4
A control valve 50 is provided in the passage 48 that removes the fuel adsorbed in the engine 1 and supplies it to the engine 1, and opens only when the engine rotates at high speed depending on the operating state of the engine. In other words, the operational stability when the engine is idling and at low speeds responds extremely sensitively to the value of the air-fuel ratio of the supplied air-fuel mixture. By discontinuing the supply of fuel, operational stability can be improved.

On the other hand, not only through the passage 48, but also through the passage 47,
Since the detached fuel from the canister 40 can also be supplied to the engine via the negative pressure regulating valve 14 and the passages 15 and 28, more detached fuel can be supplied than when only the passage 48 is used. Moreover, during idle and low speed rotation, ports 32 and 33
is on the upper end side of the throttle valve 31, so the passage 1
5, 28 or 47 are at atmospheric pressure, no fuel is removed from the coal canister 40, and the stability of the engine is not impaired in this operating state. Moreover, the activated carbon layer 41 of the carbon canister 40 also serves as an air filter, and supplies atmospheric pressure to the atmospheric pressure chamber 22 of the negative pressure regulating valve 14 through the passage 47 from the opening 45, so that Another advantage is that there is no need to communicate the air pressure chamber 22 with the atmosphere through a special filter.

[Brief explanation of drawings]

The figure is a schematic diagram of an embodiment of the present invention. 1... Engine, 2... Exhaust pipe, 3... Intake pipe, 4
... EGR passage, 5 ... EGR valve, 14 ... Negative pressure adjustment valve, 15, 28 ... Negative pressure passage, 30 ... Carburizer, 31 ... Throttle valve, 32, 33 ... Negative pressure take-out port, 40...Charcoal canister, 46...
... Separation space, 47, 48 ... Passage, 50 ... Control valve.

Claims (1)

[Claims for Utility Model Registration] A first valve formed in the intake system of an internal combustion engine, which is upstream of the throttle valve when the opening is below a predetermined opening of the carburetor throttle valve and downstream of the throttle valve when the opening is above the predetermined opening. a negative pressure port and a second negative pressure port; a negative pressure provided in a passage for recirculating exhaust gas from the exhaust system to the intake system of the internal combustion engine and introduced from the first negative pressure port via a negative pressure pipe; an exhaust gas recirculation valve that is opened and closed by a diaphragm;
an atmospheric pressure chamber that communicates with the negative pressure port of the exhaust gas recirculation valve and that is partially open to the atmosphere, and a pressure chamber that is separated from the atmospheric pressure chamber by the diaphragm and communicates with the exhaust side of the exhaust gas recirculation valve; A evaporated fuel separation device for an internal combustion engine, comprising: a negative pressure regulating valve that controls communication between the atmospheric pressure chamber and the negative pressure pipe by expanding and contracting the diaphragm; and a charcoal canister that adsorbs evaporated fuel; The coal canister is connected to the engine's intake system through an atmospheric space that is open to the atmosphere through a fuel adsorption layer that adsorbs fuel, and a first passage that has a control valve that opens and closes depending on the operating state of the engine. and a fuel withdrawal space that communicates with the atmospheric pressure chamber of the negative pressure regulating valve through a second passage, and the atmospheric pressure chamber of the negative pressure regulating valve is connected to the second passage and the fuel separation space. A vaporized fuel separation device for an internal combustion engine, characterized in that the separation space is open to the atmosphere via the fuel adsorption layer and the atmospheric space.