JPH04127858U - Engine evaporative fuel treatment device - Google Patents

Abstract

(57) [Summary] (with amendments) [Purpose] To prevent fuel liquefied in the canister from being released from the canister to the outside in an engine evaporative fuel processing device. [Structure] Includes a drain passage 6 that communicates the bottom of the canister 2 with the fuel tank 1 and returns fuel condensed in the canister 2 to the fuel tank 1, and a one-way valve 7 interposed in the middle of the drain passage 6. . It also includes an injection nozzle connected to a return passage for returning excess fuel from the fuel supply system, and a diffuser in contact with the drain passage 6, so that the fuel can be drained by injecting fuel from the injection nozzle toward the throttle channel of the diffuser. A jet pump is configured to suck the fuel in the canister 2 through the passage 6.

Description

[Detailed explanation of the idea]

0001

[Industrial application field]

The present invention relates to an improvement of an evaporative fuel processing device for an engine.

0002

[Conventional technology]

Engine evaporative fuel processing equipment is installed as part of automobile exhaust gas countermeasures. , a canister containing activated carbon is connected to the fuel tank and generated in the fuel tank. Vaporized fuel (HC) is adsorbed onto activated carbon to prevent it from being released into the atmosphere (e.g. For example, see Japanese Patent Application Laid-open No. 148259/1983).

0003

[Problem that the idea aims to solve]

However, in such conventional equipment, the evaporation collected in the canister When the amount of fuel increases and the internal weight of the canister reaches equilibrium, the canister The evaporated fuel adsorbed by the activated carbon inside the canister may condense and be released from the canister to the outside. There was room for improvement in this respect.

0004 The present invention focuses on the above points and aims to solve them.

[0005]

[Means to solve the problem]

This invention is an engine evaporative fuel treatment system that uses vapor generated from the fuel tank. A charge passage that introduces the generated fuel into the canister and a charge passage that introduces the fuel collected into the canister. A purge passage that introduces air into the engine intake passage and a large air passage that introduces atmospheric air into the canister. The air inlet is connected to the bottom of the canister and the fuel tank to condense inside the canister. A drain passage that returns fuel to the fuel tank, and a drain passage interposed in the middle of the drain passage. It is equipped with a facing valve.

[0006] In addition, in the evaporated fuel processing device, there is also a return unit that returns surplus fuel from the fuel supply system. an injection nozzle connected to the drain passage, and a diffuser connected to the drain passage. to inject fuel from the injection nozzle toward the throttle flow path of the diffuser. A jet pump is constructed to suck the fuel in the canister through the drain passage. to be accomplished.

[0007]

[Effect]

A large amount of evaporated fuel is adsorbed to the activated carbon inside the canister, and the evaporated fuel inside the canister is Under conditions where some of the fuel condenses, this liquefied fuel may pass through the drain passage. and returned to the fuel tank. Therefore, the liquefied fuel inside the canister It can be prevented from being released from the nister to the outside.

[0008] Contains evaporated fuel separated from activated carbon in the canister due to engine intake negative pressure The one-way valve closes when purge air is drawn into the intake passage through the purge passage. By closing the valve, sufficient air can flow into the canister from the air inlet, preventing evaporative combustion. This can promote the release of materials from activated carbon.

[0009] In addition, surplus fuel from the fuel supply system flows through the injection nozzle and into the diffuser. When it spills into the drain, negative pressure is created in the diffuser due to the Venturi effect, and the drain Forces condensed and evaporated fuel from inside the canister through the canister to the fuel tank. suction inside. As a result, under operating conditions where there is a lot of evaporated fuel from the fuel tank, Also, it is possible to reliably prevent fuel from being released from the canister to the outside.

0010

【Example】

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

[0011] As shown in Figure 1, vaporized fuel generated from fuel tank 1 is introduced into canister 2. The fuel adsorbed in the canister 2 is transferred to the charge passage 3 of the engine (not shown). A purge passage 4 introduced into the intake passage is provided.

0012 Activated carbon is contained inside the canister 2, and this active end adsorbs evaporated fuel. At the same time, vaporized fuel is released into the air flowing in from the atmosphere inlet 5 during engine operation. The air containing evaporated fuel (purge air) is passed from the purge passage 4 through the intake passage. It is sent to a combustion chamber where it is burned.

[0013] The present invention is a drain that collects the fuel condensed in the canister 2 and returns it to the fuel tank 1. A tunnel 6 is provided. One end of this drain passage 6 opens at the bottom of the canister 2. , the fuel liquefied in the canister 2 flows into the drain passage 6. Ru. The other end of the drain passage 6 is connected to the upper part of the tank 1, and the canister 2 is connected to the upper part of the tank 1. It is provided at a position higher than 1.

[0014] A one-way valve (check valve) 7 is interposed in the middle of the drain passage 6. . This one-way valve 7 includes a valve body (not shown) and a spring that biases the valve body to close. A certain amount of condensed fuel is contained in the drain passage 6 on the upstream side of the one-way valve 7. When the fuel accumulates, the valve element opens against the spring and returns the condensed fuel to tank 1. It has become.

[0015] A large amount of evaporated fuel is adsorbed to the activated carbon in the canister 2 through the charge passage 3. Under the condition that the internal weight of canister 2 reaches an equilibrium state, canister 2 The evaporated fuel in the canister condenses and accumulates at the bottom of the canister 2, and a drain opens at the bottom. The water flows into the tank 1 through the one-way valve 7 and returns to the tank 1. Therefore, the key The fuel liquefied in the canister 2 can be prevented from flowing out from the canister 2. Ru.

[0016] In addition, since a one-way valve 7 is interposed in the middle of the drain passage 6, the engine When purge air is sucked into the intake passage through the purge passage 4 due to suction negative pressure When the one-way valve 7 closes, the atmosphere enters the canister 2 from the atmosphere inlet 5. can sufficiently flow in and promote the separation of evaporated fuel from the activated carbon.

[0017] Next, another embodiment shown in FIG. 2 will be described.

[0018] A drain passage 6 is provided to collect fuel condensed in the canister 2 and return it to the fuel tank 1. A one-way valve 7 is interposed in the middle of the drain passage 6, and this drain A jet pump 9 for sucking fuel into the tank 1 is provided at one end of the passage 6.

[0019] As shown in FIG. 3, the jet pump 9 is located at the end of the return passage 8 of the fuel supply system. It is equipped with a jet nozzle 13 formed by narrowing the end, and this jet nozzle 13 has a A diffuser 11 is provided which has a throttle channel 14 that opens in opposition to each other. The drain passage 6 is connected to the upstream side of the throttle passage 14 of the user 11 .

[0020] When fuel is ejected from the jet nozzle 13 into the throttle channel 14, the Venturi effect occurs. As a result, negative pressure is generated in the diffuser 11, and the pressure flows through the drain passage 6 and through the one-way valve 7. The condensed fuel and evaporated fuel in the canister 2 are sucked into the tank 1. others Therefore, under operating conditions where there is a large amount of evaporated fuel generated in tank 1, Filled evaporated fuel and liquefied fuel inside canister 2 are released from canister 2 to the outside. It can prevent leakage.

[0021] In addition, the fuel supply system was sucked from tank 1 by a fuel supply pump (not shown). Fuel is pumped to each fuel injection valve through a supply passage, and the fuel pressure in this fuel supply passage A pressure regulator is provided to adjust the differential pressure between the air pressure and the intake passage pressure to a constant level. , excess fuel flows from the pressure regulator to the tank 1 through the return passage 8. It is set to be returned to .

[0022] The flow rate of surplus fuel returned from the return passage 8 increases as the engine speeds lower. However, in the diffuser 11, depending on the flow rate of surplus fuel returned from the return passage 8, A negative pressure is generated and the amount of fuel returned from the canister 2 through the drain passage 6 also increases. Ru.

[0023]

[Effect of the idea] As explained above, the present invention uses a key that adsorbs evaporated fuel generated from the fuel tank. In an engine vaporized fuel processing system equipped with a canister, etc., the bottom of the canister and A drain that communicates with the fuel tank and returns fuel that condenses in the canister to the fuel tank. The canister is equipped with a passageway and a one-way valve inserted in the middle of the drain passage The fuel liquefied inside can be prevented from being released from the canister to the outside.

[0024] In addition, in the evaporative fuel processing device of the above engine, surplus fuel from the fuel supply system is The injection nozzle connected to the return passage that returns the water, and the diode connected to the drain passage mentioned above. It is equipped with a fuser and injects fuel from the injection nozzle toward the throttle flow path of the diffuser. A jet that sucks the fuel in the canister through the drain passage by Because of the pump configuration, the canister can be easily operated even under operating conditions with a large amount of evaporated fuel from the fuel tank. It is possible to reliably prevent fuel from being discharged from the star to the outside.

[Brief explanation of drawings]

FIG. 1 is a configuration diagram showing an embodiment of the present invention.

FIG. 2 is a configuration diagram showing another embodiment.

FIG. 3 is a configuration diagram of the same jet pump.

[Explanation of symbols]

1 Fuel tank 2 Canister 3 Charge passage 4 Purge passage 5 Atmosphere inlet 6 Return passage 7 One-way valve 8 Fuel return passage 9 Jet pump 11 Diffuser 13 Injection nozzle 14 Throttle channel

Claims (2)

[Scope of utility model registration request] Claim 1: A charge passage for introducing evaporated fuel generated from a fuel tank into a canister, a purge passage for introducing fuel recovered in the canister into an intake passage of an engine, and an atmosphere inlet for introducing atmospheric air into the canister. , an engine evaporator comprising: a drain passage that communicates the bottom of the canister with the fuel tank and returns fuel condensed in the canister to the fuel tank; and a one-way valve interposed in the middle of the drain passage. Fuel processing equipment. 2. An injection nozzle connected to a return passage for returning excess fuel from the fuel supply system and a diffuser connected to the drain passage, the fuel being injected from the injection nozzle toward a throttle channel of the diffuser. 2. The evaporated fuel processing device for an engine according to claim 1, further comprising a jet pump that sucks the fuel in the canister through the drain passage.