JP2007205231A - Evaporated fuel treatment device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To reduce electric energy consumption by reducing load of a fuel pump in an evaporated fuel treatment device preventing evaporated fuel formed in a fuel tank from being discharged to atmosphere. <P>SOLUTION: A canister 22 adsorbing evaporated fuel formed in the fuel tank 11, and a purge pump 23 forcibly introducing evaporated fuel in the canister 22 to an in take air passage 21 of an engine E. Exhaust gas exhausted from the engine E is circulated to the purge pump 23, and the purge pump 23 is driven by using flow speed energy of exhaust gas as a power source. Consequently, the purge pump 23 can be driven without increasing load of a fuel pump 12. And electric energy consumed by the fuel pump 12 can be reduced. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to an evaporative fuel processing apparatus for preventing evaporative fuel generated in a fuel tank from being released into the atmosphere.

  Conventionally, an evaporative fuel processing apparatus used for an internal combustion engine using fuel such as gasoline is known (see Patent Document 1). The evaporative fuel processing apparatus includes a canister that adsorbs the evaporated fuel generated in the fuel tank, and a purge pump that forcibly introduces the evaporated fuel adsorbed by the canister into the intake passage of the internal combustion engine. According to this fuel vapor processing apparatus, the fuel vapor volatilized in the fuel tank is introduced into the intake passage. Therefore, the evaporated fuel processing apparatus can prevent the evaporated fuel from being released into the atmosphere.

  Patent Document 1 describes an injector that injects fuel toward an internal combustion engine, an electric fuel pump that discharges fuel from a fuel tank toward the injector, a fuel supply pipe that connects the fuel pump and the injector, and the like. Yes. A purge pump described in Patent Document 1 is branched by a fuel supply pipe and circulates fuel to a fuel tank, a Pelton impeller rotated by fuel flowing through the branch pipe, and a rotational force of the Pelton impeller. And a turbine blade for introducing the evaporated fuel into the intake passage. That is, the purge pump described in Patent Document 1 is driven by using the flow velocity energy of the fuel discharged from the fuel pump as a power source.

Japanese Patent Laid-Open No. 11-30158

  However, in the evaporative fuel processing apparatus described in Patent Document 1, the power source of the purge pump is the flow velocity energy of the fuel by the electric fuel pump. As a result, the load on the fuel pump increases. Therefore, the electrical energy consumed by the fuel pump increases.

  Accordingly, an object of the present invention is to provide an evaporative fuel processing apparatus that reduces the consumption of electric energy by reducing the load on the fuel pump.

  In the invention according to any one of claims 1 to 4, the purge pump forcibly evaporates the fuel adsorbed by the canister into the intake passage of the internal combustion engine using the flow velocity energy of the exhaust gas discharged from the internal combustion engine as a power source. To introduce. Therefore, the purge pump can be driven without increasing the load of the fuel pump. Therefore, the consumption of electric energy consumed by the fuel pump can be reduced.

  Here, the evaporative fuel processing apparatus described in Patent Document 1 needs to circulate the fuel from the fuel supply pipe to the fuel tank via the purge pump. Then, in order to prevent the fuel from leaking from the circulation path, the circulation path is required to have high airtightness. For example, the joint portion of the branch pipe needs a structure with high sealing performance. Therefore, the fuel vapor processing apparatus described in Patent Document 1 is costly. On the other hand, in the invention according to any one of claims 1 to 4, the purge pump is driven using the flow velocity energy of the exhaust gas as a power source. And the path | route which distribute | circulates waste gas to a purge pump does not require high airtightness compared with the path | route of patent document 1 which circulates a fuel. Therefore, the structure can be simplified.

  In the third aspect of the invention, the exhaust gas generated in the internal combustion engine is introduced into the intake passage by the purge pump and is again taken into the internal combustion engine. Therefore, regarding the exhaust gas released from the internal combustion engine to the atmosphere, the amount of hydrocarbons contained in the exhaust gas can be reduced.

  In the invention according to claim 4, the exhaust gas flowing to the purge pump passes through the catalyst. Therefore, the required degree of airtightness in the connection portion of the path through which the exhaust gas flows to the purge pump can be further reduced. Therefore, further cost reduction can be achieved.

Hereinafter, a plurality of embodiments of the present invention will be described with reference to the drawings.
(First embodiment)
An evaporated fuel processing apparatus according to a first embodiment of the present invention is shown in FIGS. 1 and 2. FIG. 1 is a schematic view showing a fuel piping system of an automobile such as a gasoline engine-equipped car. FIG. 2 is a cross-sectional view showing the purge pump shown in FIG.

  The evaporated fuel processing apparatus 1 of this embodiment is mounted on an automobile having an internal combustion engine (hereinafter referred to as an engine) E such as a gasoline engine. A combustion chamber is formed between a cylinder and a piston (not shown) of the engine E.

  The intake pipe 2 forms an intake passage 21 through which the air-fuel mixture flows toward the combustion chamber. The intake pipe 2 is connected to the combustion chamber. Liquid fuel (for example, highly volatile fuel such as gasoline) is injected into the intake pipe 2 from the fuel injection device 3. A throttle valve 4 that opens and closes in conjunction with an accelerator pedal (not shown) is provided upstream of the intake pipe 2. The exhaust pipe 5 forms an exhaust passage 53 for discharging exhaust gas generated in the combustion chamber. The exhaust pipe 5 is connected to the combustion chamber. In the exhaust pipe 5, a catalytic converter 51 for purifying exhaust gas is disposed.

  First, the fuel injection device 3 of this embodiment will be described with reference to FIG. The fuel injection device 3 includes a fuel tank 11 that stores liquid fuel, an electric fuel pump 12 that pressurizes and supplies the liquid fuel in the fuel tank 11, a fuel branch pipe 13 provided in the intake pipe 2 of the engine E, The fuel branch pipe 13 includes a plurality of fuel injection valves (injectors) 14, a main fuel passage 15 that connects the fuel pump 12 and the fuel branch pipe 13, and the like.

  The fuel tank 11 is mounted between a vehicle compartment and a trunk room of the automobile. A filler neck 16 that forms a fuel supply passage is provided on the side of the fuel tank 11 so as to extend obliquely upward. A filler cap 17 is attached to the tip of the filler neck 16. Further, a purge hole (not shown) for guiding the evaporated fuel vapor to the fuel vapor processing apparatus 1 is formed in the ceiling portion of the fuel tank 11.

  The fuel pump 12 sucks liquid fuel from the fuel tank 11 and pumps it to the fuel branch pipe 13, and is accommodated in the fuel tank 11. The fuel branch pipe 13 distributes the liquid fuel pressure-fed from the fuel pump 12 to each fuel injection valve 14, and the pressure of the liquid fuel in the fuel branch pipe 13 is set to a predetermined value by a pressure adjustment valve 19. It is regulated to pressure. The surplus liquid fuel at the time of this pressure adjustment is returned to the fuel tank 11 through the return pipe 18. The fuel injection valve 14 is housed in a fuel branch pipe 13 attached to the intake pipe 2, and liquid fuel is atomized into each intake port of the intake pipe 2 of the engine E based on an injection signal from the engine ECU 40. Atomized and sprayed directly.

  Next, the evaporative fuel processing apparatus 1 of this embodiment is demonstrated based on FIG. The evaporative fuel processing apparatus 1 is composed of components such as a canister 22 and a purge pump 23. The evaporative fuel processing apparatus 1 introduces (purifies) evaporative fuel (evaporative gas) volatilized in the fuel tank 11 into the intake pipe 2 of the engine E through the canister 22 and the purge pump 23, thereby evaporating fuel into the atmosphere. It is a device that prevents it from being released.

  The canister 22 has an adsorbent (not shown) such as activated carbon that adsorbs the evaporated fuel generated in the fuel tank 11. Thereby, the canister 22 can adsorb the evaporated fuel volatilized in the fuel tank 11 through the purge hole. The canister 22 is formed with an air hole 26 opened to the atmosphere so that air can be sucked into the inside. A canister control valve (canister control valve) 27 for closing the air hole 26 is attached to the air hole 26 as necessary. The canister control valve 27 is an electromagnetic on-off valve that closes when energized.

  Next, the purge pump 23 will be described with reference to FIG. The purge pump 23 is a pump that forcibly introduces the evaporated fuel in the canister 22 into the intake pipe 2 using the flow velocity energy of the exhaust gas discharged from the combustion chamber of the engine E as a power source.

  The purge pump 23 is a so-called side channel pump and includes a Pelton impeller 32, casings 31 and 34, a turbine 73, and the like. A Pelton impeller 32 is rotatably disposed inside the casing 31. The Pelton impeller 32 corresponds to the first impeller described in the claims. The turbine 73 corresponds to the second impeller described in the claims. The casing 31 is provided in the exhaust pipe 5 on the downstream side (muffler side) of the catalytic converter 51 (see FIG. 1). The rotational speed of the Pelton impeller 32 changes according to the flow rate of the exhaust gas flowing through the exhaust pipe 5.

  The casing 31 is integrally provided with a pipe 35. This pipe 35 is connected to the exhaust pipe 5. The casing 31 communicates with the exhaust pipe 5 through the pipe 35. The pipe 35 corresponds to the exhaust gas introduction pipe described in the claims. The pipe 35 and the exhaust pipe 5 may be connected using a flexible hose. If a flexible hose is used, it can reduce that the vibration of the engine E is propagated to the evaporative fuel processing apparatus 1. FIG.

  A turbine 73 is disposed inside the casing 34. The rotating shaft 33 of the Pelton impeller 32 is connected to the turbine 73 via magnet couplings 71 and 72. Concave portions 75 are respectively formed on both end surfaces of the turbine 73 so as to correspond to the concave portions 74 formed on the inner wall surface of the casing 34.

  The inlet pipe 36 integrally formed with the casing 34 is connected to the outlet of the canister 22 via the suction side purge pipe 24. The suction side purge pipe 24 circulates the evaporated fuel in the canister 22 toward the purge pump 23. An outlet pipe 38 integrally formed with the casing 34 is connected to the intake pipe 2 via the discharge side purge pipe 25. The discharge side purge pipe 25 circulates the evaporated fuel in the purge pump 23 toward a portion of the intake pipe 2 between the downstream of the throttle valve 4 and each intake port of the combustion chamber.

  The evaporated fuel processing apparatus 1 includes a bypass pipe 37 that is connected to the exhaust pipe 5 and bypasses the exhaust gas flowing through the exhaust pipe 5 with respect to the casing 35. A bypass valve 8 that adjusts the flow rate of exhaust gas is disposed in the middle of the bypass pipe 37. The bypass valve 8 is an electromagnetic proportional control valve that adjusts the passage resistance of the bypass pipe 37 by changing the opening area of the bypass pipe 37 according to the energization amount.

  Accordingly, the flow rate of the exhaust gas flowing into the casing 35 increases as the bypass valve 8 decreases the opening area of the bypass pipe 37. Therefore, the amount of evaporated fuel discharged from the purge pump 23 increases. Conversely, as the bypass valve 8 increases the opening area of the bypass pipe 37, the flow rate of the exhaust gas flowing into the casing 35 decreases. As a result, the amount of fuel vapor discharged from the purge pump 23 decreases.

  Therefore, the amount of evaporated fuel discharged from the purge pump 23 can be adjusted by controlling the valve opening of the bypass valve 8. For example, when the bypass valve 8 is closed, the discharge amount of the evaporated fuel from the purge pump 23 becomes the maximum discharge amount. Further, when the bypass valve 8 is opened, the discharge amount of the evaporated fuel from the purge pump 23 becomes the minimum discharge amount.

  The outlet pipe 38 is provided with a purge control valve 9 that adjusts the flow rate of the evaporated fuel introduced into the intake pipe 2 of the engine E. The purge control valve 9 includes a case 90, a valve 92, an electromagnetic coil 94, and the like. The case 90 is integrally formed with the root portion of the outlet pipe 38 of the casing 34 of the purge pump 23. In the case 90, a communication path 91 that connects the outlet port 77 of the purge pump 23 and the outlet pipe 38 is formed. The valve 92 is driven by a magnetic attractive force generated by energizing the electromagnetic coil 94 to open and close the communication path 91.

  The purge control valve 9 is a flow rate control valve that changes the purge flow rate of the evaporated fuel supplied to the intake pipe 2 of the engine E based on the duty ratio between the valve opening time and the valve closing time. The purge control valve 9 is an electromagnetic on-off valve that opens the valve 92 when the electromagnetic coil 94 is energized. Thereby, when the supply of the evaporated fuel is stopped, the valve 92 of the purge control valve 9 may be closed.

  As described above, according to the present embodiment, the purge pump 23 of the evaporated fuel processing apparatus 1 is driven using the flow velocity energy of the exhaust gas discharged from the combustion chamber of the engine E as a power source. That is, the Pelton impeller 32 rotates by the flow velocity energy of the exhaust gas, and the turbine 73 rotates by the rotational force. Therefore, the evaporated fuel is forcibly introduced into the intake pipe 2 by the rotation of the turbine 73. Therefore, the purge pump 23 can be driven without increasing the load of the fuel pump 12. Therefore, the consumption of electric energy consumed by the fuel pump 12 can be reduced.

  Further, according to the present embodiment, the purge pump 23 is driven by using the flow velocity energy of the exhaust gas as a power source by using the fluid flowing through the casing 31 of the purge pump 23 as the exhaust gas. Therefore, the path through which the exhaust gas is circulated to the purge pump 23 does not require high airtightness as compared with the case where the fluid circulated through the casing 31 is liquid fuel. Specifically, high airtightness is not required in the connection portion between the casing 31 and the pipe 35, the connection portion between the pipe 35 and the exhaust pipe 5, and the portion other than the portion connected to the pipe 35 in the casing 35. Therefore, the cost of the evaporative fuel processing apparatus 1 can be reduced.

Here, the fuel vapor processing apparatus described in Patent Document 1 described above uses the flow velocity energy of the fuel discharged from the fuel pump as a drive source for the purge pump. Therefore, for example, the flow rate of the fuel flowing to the purge pump is large during idling. Therefore, the evaporated fuel introduced into the intake pipe by the purge pump increases. Then, the concentration of the air-fuel mixture at the time of idling increases. Therefore, fuel consumption deteriorates. Further, regarding the exhaust gas released from the engine E to the atmosphere, the amount of hydrocarbons contained in the exhaust gas increases.
On the other hand, the evaporative fuel processing apparatus 1 of the present embodiment is driven using the flow velocity energy of the exhaust gas discharged from the combustion chamber of the engine E as a power source. Therefore, the flow rate of exhaust gas is small during idling. Therefore, the evaporated fuel introduced into the intake pipe 2 by the purge pump 23 is reduced. As a result, the concentration of the air-fuel mixture during idling decreases. Therefore, fuel efficiency is improved. Further, regarding the exhaust gas released from the engine E to the atmosphere, the amount of hydrocarbons contained in the exhaust gas is reduced.

(Second Embodiment)
Hereinafter, a second embodiment of the present invention will be described with reference to FIGS. 3 and 4. In addition, the same code | symbol is attached | subjected to the component substantially the same as 1st Embodiment, and description is abbreviate | omitted. FIG. 3 is a schematic diagram showing a fuel piping system of the evaporated fuel processing apparatus 1 according to the second embodiment. 4 is a cross-sectional view of the purge pump shown in FIG.

  The purge pump 230 is a so-called jet pump, and includes a jet nozzle 231 that ejects exhaust gas, a casing 232 that accommodates the jet nozzle 231 inside, and the like. An exhaust gas supply pipe 233 communicating with the jet nozzle 231 is connected to the casing 232. An exhaust gas introduction pipe 52 communicating with the exhaust gas supply pipe 233 is connected to the exhaust pipe 5. A part of the exhaust gas that has passed through the catalytic converter 51 is branched by the exhaust gas introduction pipe 52 and flows into the exhaust gas introduction pipe 52. The exhaust gas flowing into the exhaust gas introduction pipe 52 is ejected from the jet nozzle 231 into the casing 232 via the exhaust gas supply pipe 233.

  A chamber portion 234 is formed in the casing 232 in the downstream portion of the jet nozzle 231 outlet. A suction pipe 235 that communicates with the chamber portion 234 is connected to the casing 232. The suction pipe 235 is connected to the suction side purge pipe 24 similar to the first embodiment. In addition, a throat pipe 236 that communicates with the chamber portion 234 is connected to a portion of the casing 232 facing the jet nozzle 231. The throat pipe 236 is connected to the discharge side purge pipe 25 similar to that of the first embodiment.

  With the above configuration, when exhaust gas is ejected from the jet nozzle 231 into the casing 232, a negative pressure is generated in the chamber portion 234. Then, the evaporated fuel is sucked into the casing 232 from the suction pipe 235. Then, the evaporated fuel sucked into the casing 232 is pressure-fed from the throat pipe 236 to the discharge side purge pipe 25 together with the exhaust gas ejected to the casing 232.

  Therefore, according to the second embodiment, the following effects are exhibited in addition to the same effects as the first embodiment. That is, the exhaust gas generated in the engine E is introduced into the intake pipe 235 by the purge pump 230 and is sucked into the engine E again. Therefore, regarding the exhaust gas released from the engine E to the atmosphere, the amount of hydrocarbons contained in the exhaust gas can be reduced.

(Other embodiments)
In each of the above embodiments, the exhaust gas to be introduced into the purge pumps 23 and 230 is taken from the downstream portion of the exhaust pipe 5 from the catalytic converter 51. You may make it take in exhaust gas from an upstream part.
As described above, the present invention is not limited to the above-described embodiment, and can be applied to various embodiments without departing from the gist thereof.

The schematic diagram of the fuel piping system of a motor vehicle which shows the evaporative fuel processing apparatus by 1st Embodiment of this invention. Sectional drawing of the purge pump shown in FIG. The schematic diagram of the fuel piping system of a motor vehicle which shows the evaporative fuel processing apparatus by 2nd Embodiment of this invention. Sectional drawing of the purge pump shown in FIG.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 1: Evaporative fuel processing apparatus, 11: Fuel tank, 22: Canister, 21: Intake passage of internal combustion engine, 23, 230: Purge pump, 32: Pelton impeller (first impeller), 52: Exhaust gas introduction pipe, 53 : Exhaust passage of internal combustion engine, 73: turbine (second impeller), 231: jet nozzle, 232: casing, E: engine (internal combustion engine)

Claims (4)

A canister that adsorbs the evaporated fuel generated in the fuel tank;
An evaporative fuel processing apparatus comprising: a purge pump that forcibly introduces evaporative fuel adsorbed by the canister into an intake passage of the internal combustion engine using flow velocity energy of exhaust gas discharged from the internal combustion engine as a power source.   The said purge pump has a 1st impeller rotated with the flow velocity energy of the said waste gas, and a 2nd impeller which introduce | transduces the said fuel vapor into the said intake passage with the rotational force of the said 1st impeller. Evaporative fuel processing device.   The purge pump has a jet nozzle that injects the exhaust gas, and a casing that accommodates the jet nozzle, and the evaporated fuel is combined with the exhaust gas by suction pressure generated in the casing by injection from the jet nozzle. The evaporative fuel processing apparatus according to claim 1, wherein the evaporative fuel processing apparatus is introduced into the intake passage. An exhaust gas introduction pipe having one end connected to the purge pump;
The evaporative fuel processing device according to any one of claims 1 to 3, wherein the other end of the exhaust gas introduction pipe is connected to a downstream side of a catalyst that purifies exhaust gas in an exhaust passage of the internal combustion engine.

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