JPH04111558U - Vapor lock prevention device - Google Patents

Abstract

(57) [Summary] [Purpose] To improve engine startability by returning fuel including vapor remaining in the fuel passage to the fuel tank for a certain period of time regardless of the fuel temperature when starting the engine. [Structure] A solenoid valve 27 is assembled to the fuel pressure regulating valve 12. The fuel pressure regulating valve 1 is attached to the body 51 of the solenoid valve 27.
A bypass passage 28 is formed to bypass the second valve opening/closing section. When the coil 57 of the solenoid valve 27 is de-energized (de-energized), the bypass passage 28 is cut off, and the coil 5
When the power to 7 is turned on (when energized), the bypass passage 2
8 is communicated. The coil 57 is energized for a predetermined time based on an output signal from the electronic control unit 25 when the engine 1 is started, and the solenoid valve 27 is opened only during that time. Therefore, at the time of starting the engine, by opening the solenoid valve 27, the remaining fuel in the fuel passage 11 passes from the bypass passage 28 to the fuel return passage 14 to the fuel tank 8.
be sent back to.

Description

[Detailed explanation of the idea]

0001

[Industrial application field]

This invention eliminates engine radiant heat in the fuel passage where fuel is pumped from the fuel pump. A fuel tank designed to return vaporized fuel (vapor) generated by Regarding the parking prevention device.

0002

[Conventional technology]

Conventionally, as this type of vapor lock prevention device, for example, There is one disclosed in Publication No. 63. The device of this publication is shown in cross-section in FIG. As shown, a fuel passage 70 that sends pressurized fuel from the fuel pump to the fuel injection valve , the pressurized fuel in the fuel passage 70 is transferred to a fuel return passage 71 communicating with the fuel tank. a fuel pressure adjustment valve 72 that adjusts the fuel pressure by returning the fuel pressure; The fuel temperature is low between the fuel passage side and the fuel return passage side in the regulating valve 72. When the temperature corresponding to the occurrence is reached, the deformation is activated and the fuel passage 70 and the fuel return An opening/closing device equipped with a restorable heat deformable element (bimetal, etc.) 75 that communicates with the passage 71. A valve 74 is provided.

0003

[Problem that the idea aims to solve]

However, according to the above-mentioned publication device, the opening/closing device provided in the fuel pressure regulating valve 72 The thermal deformation element 75 of the valve 74 deforms depending on the temperature of the fuel in the fuel pressure regulating valve 72. It works. In addition, the fuel pressure regulating valve 72 is connected to each cylinder of the engine. Because it is farther away from the engine compared to the delivery pipe that supplies fuel to the injector. , the influence of engine radiant heat when the engine is stopped is small. For this reason, the fuel temperature inside the delivery pipe reaches a temperature that corresponds to vapor generation. Despite the fact that the fuel temperature in the fuel pressure regulating valve 72 corresponds to vapor generation A situation may occur where the specified temperature has not been reached. When starting the engine under these conditions, Since the on-off valve 74 does not open, the problem of poor starting remains. Also, when the fuel temperature inside the fuel pressure regulating valve 72 is low, air is added to the fuel. Or it may contain vapor due to low volatile components. like this Even when the engine is started under such conditions, the on-off valve 74 will not open, resulting in a starting problem. Problems remain.

0004 Therefore, the present invention was devised to solve the above-mentioned problems. The purpose is to eliminate the remaining fuel in the fuel passages regardless of the fuel temperature when starting the engine. The fuel is returned to the fuel tank for a certain period of time, improving engine starting performance. An object of the present invention is to provide a vapor lock prevention device.

[0005]

[Means to solve the problem]

The vapor lock prevention device of the present invention that solves the above problems is as follows: a fuel passage that sends pressurized fuel from the fuel pump to the fuel injection valve; Returning the pressurized fuel in the fuel passage to a fuel return passage communicating with the fuel tank a fuel pressure regulating valve that regulates fuel pressure by a bypass passage that bypasses the valve opening/closing part of the fuel pressure regulating valve; It is installed in the bypass passage and is opened for a predetermined period of time when the engine is started. a solenoid valve, It is equipped with

[0006]

[Effect]

According to the above means, when the engine is started, the solenoid valve is opened for a predetermined period of time. , the fuel remaining in the fuel passage passes from the bypass passage to the fuel return passage. sent back to the tank.

[0007]

【Example】

[Example 1] Embodiment 1 of the present invention will be described according to the drawings. First, please refer to Figure 2, which shows a schematic diagram of the engine fuel supply system. I will refer to and explain. Air from air filter 3 is connected to an accelerator pedal (not shown). The air is inhaled in response to the opening of the throttle valve 2, which is operated by moving the air connector. Connect the surge tank 6 and intake manifold 7 from the air flow meter 5 installed in It is supplied to the engine 1 through the engine. On the other hand, the fuel in the fuel tank 8 is pressurized by a fuel pump 10 via a fuel filter 9. After that, the fuel pressure regulating valve 12 on the fuel passage 11 connects the control valve 12 and the surge tank. The difference between the intake pressure and the fuel pressure detected in the negative pressure passage 13 connecting 6 is always constant. In addition, the injector for each cylinder is controlled from the delivery pipe 15 to (Fuel injection valve) 16, and excess fuel flows through the fuel return passage 14. The fuel is then returned to the fuel tank 8.

[0008] Further, the fuel passage 11 is branched in the middle, and the pressurized fuel is supplied to the surge tank 6. It is also supplied to the tart injector 17. Then, the valve upstream of throttle valve 2 Via the bypass air passage 18 that communicates between the air side intake passage and the surge tank 6 The amount of intake air supplied during cold idle rotation is controlled by the air valve 19 on the passage 18. controlled by Each of the fuel pump 10, start injector 17 and air valve 19 These are the outputs of the starter switch 20 and starter injector time switch 21. The injector 16 is controlled by an air flow meter 5 and a water temperature sensor 22. , the amount of intake air from the O2 sensor 23 and the ignition coil 24, the cooling water temperature, and the fuel An electronic control unit ( It is controlled by the output of ECU) 25.

[0009] Next, regarding the fuel pressure regulating valve 12 constituting the vapor lock prevention device, This will be described in detail with reference to FIG. 1 showing a cross section thereof. Casing 3 formed into a substantially cylindrical shape 1 consists of two cover bodies 32 and 33 that are vertically divided into halves. cover body 32, 33 are coupled with a diaphragm 35 sandwiched between them. This diaph The inside of the casing 31 is divided into an upper negative pressure chamber 36 and a lower fuel chamber 37 by the ram 35. It is sectioned.

0010 The negative pressure passage 13 is connected to the negative pressure connecting pipe 38 attached to the side surface of the cover body 32. is communicated. The fuel inlet pipe 39 attached to the side surface of the cover body 33 has the A fuel passage 11 is communicated. Further, a substantially cylindrical sheet holding member 40 is fixed to the bottom surface of the cover body 33. S A fuel discharge pipe 41 is connected to the lower part of the hollow hole of the seat holding member 40 . This discharge pipe 41 is communicated with the fuel return passage 14. Also, the hollow hole of the sheet holding material 40 A hollow cylindrical sheet member 42 is press-fitted into the upper part of the housing. This sheet member 42 The tip (upper end in the figure) serves as a valve seat 43. Note that the sheet holding material 40 of this example is It forms part of the body 51 of the electromagnetic valve 27 described above.

[0011] At the center of the diaphragm 35, a lower diaphragm holding member 45 and its An upper spring receiving member 46 is attached. To the diaphragm holding member 45 A valve member 44 that opens and closes the valve seat 43 is provided. In addition, the spring receiving part The valve member 44 is urged in the valve closing direction between the material 46 and the upper surface of the upper cover body 32. A spring 47 is interposed.

0012 A solenoid valve 27 described below is integrally assembled to the fuel pressure regulating valve 12. There is. The body 51 of the electromagnetic valve 27 is integrally formed with the seat holding material 40, and It has a block shape spanning the fuel inlet pipe 39 and the fuel discharge pipe 41. body 5 1, a bypass passage 28 is formed in a substantially L-shape. This bypass passage 28 The fuel passage 11 and the fuel passage 11 are connected to each other through the side surfaces of the fuel inlet pipe 39 and the fuel discharge pipe 41. The valve opening/closing portion (valve seat 4) of the fuel pressure regulating valve 12 communicates with the 3 and the valve member 44). Also, at the bending part of the bypass passage 28 A valve chamber 53 is formed that opens at the bottom surface of the body. On the upper surface of this valve chamber 53 A seat portion 54 is formed.

[0013] The body 51 includes a case made of a ferromagnetic material that covers the valve chamber 53 and its surrounding area. 55 is attached. Inside the case 55 is a synthetic resin wrapped around a coil 57. A manufactured bobbin 56 is housed therein. An annular shape is formed between this bobbin 56 and the body 51. An auxiliary magnetic pole 58 is interposed.

[0014] A substantially cylindrical stator 59 is inserted into the hollow cylinder of the bobbin 56 . Also A cylindrical armature 60 is disposed on the valve chamber side in the hollow cylinder of the bobbin 56 in the axial direction (not shown). It is inserted so that it can move in the vertical direction). The armature 60 has a tip (not shown). It has a valve body 61 at the upper end). This valve body 61 is made of a suitable material such as rubber or synthetic resin. It is made of an appropriate elastic body and closes the seat portion 54. The armature 60 is The bobbin 56 is slid and guided by a guide tube 62 fitted into the hollow cylinder. child There is always an armature 60 between the armature 60 and the stator 59. A spring 63 is interposed to bias upward.

[0015] In the solenoid valve 27 described above, when the coil 57 is de-energized (de-energized), 1, the armature 60 is moved by the spring load of the spring 63. The valve body 61 closes the seat portion 54 of the valve chamber 53. By this, the bypass passage 28 is blocked. Also, the power to the coil 57 is turned on. When it is turned on (when energized), the armature 60, stator 59, case 55, and auxiliary magnet A magnetic path of magnetic lines of force is formed by the poles 58 between the armature 60 and the stator 59. An electromagnetic force is generated. This electromagnetic force overcomes the spring load of spring 63. As a result, the armature 60 is attracted to the stator 59 as shown in FIG. When the valve body 61 is separated from the seat portion 54, the bypass passage 28 is communicated with the valve body 61. be done.

[0016] Note that the coil 57 is energized by the electronic control unit when the engine 1 is started. For example, the output signal from the delivery pipe 15 may remain in the delivery pipe 15 for a predetermined time. This is carried out for a sufficient period of time to return the existing fuel to the fuel tank 8. The solenoid valve 27 is in the open state only during this period. Valve opening related to control of this solenoid valve 27 Power signals include circuit opening relays, pump relays, and starter signals. , ignition on signal, etc. can be used, and a delay signal can be used as a valve closing input signal. A circuit, counting by electronic control unit 25, etc. can be used.

[0017] The operation of this embodiment will be explained. First, when the engine is running, the intake pressure from the surge tank 6 is controlled by the fuel pressure regulating valve 12. The negative pressure is transmitted to the negative pressure chamber 36, and this negative pressure and the fuel pressure in the spring 47 and the fuel chamber 37 are combined. Due to the balance, the difference between the fuel pressure on the fuel passage side and the intake pressure is always constant. The excess fuel is returned to the fuel tank 8 through the fuel return passage 14. It will be done. In this state, fuel is constantly flowing and the fuel temperature is low, causing no vapor. - is unlikely to occur, and even if it occurs, the vapor will be discharged by opening the valve member 44. It escapes from the fuel return passage 14 to the fuel tank 8 through the pipe 41. Also this At this time, the solenoid valve 27 is in a closed state and the bypass passage 28 is blocked. There is no problem with the function of the fuel pressure regulating valve 12.

[0018] On the other hand, when the engine 1 is stopped, the negative pressure chamber 36 of the fuel pressure regulating valve 12 is at atmospheric pressure. Therefore, the valve member 44 closes and the fuel remaining in the fuel passage 11 is removed from the engine. The fuel pressure would be maintained at that time and the fuel would be trapped. Therefore, the engine The vapor generated in the fuel passage 11 in the high temperature state immediately after the engine stops has no place to escape. This will cause problems with engine operation when starting the engine, but this example In this case, when the engine starts, the solenoid valve is activated in response to the output signal from the electronic control unit 25. 27 is opened for a predetermined period of time, the vapor remaining in the fuel passage 11 is removed. The fuel contained in the bypass passage 28 passes through the fuel return passage 14 to the fuel tank 8. and sent back, that is, purged. As a result, the waste generated inside the fuel passage 11 Problems such as engine starting failure due to parking are resolved. In addition, fuel passage 11 The fuel remaining in the tank is at least the delivery port where a lot of vapor is likely to be generated. Any fuel remaining in the pipe 15 may be used. Furthermore, after a predetermined period of time has elapsed since the engine started, the solenoid valve 27 closes and the engine This is the state when the engine is running.

[0019] [Example 2] Example 2 of the present invention will be described. The cross-sectional view of the vapor lock prevention device of this example is shown in Figure 3. It is shown in This example is a partial modification of Example 1, so the main points are the same. By assigning the same reference numerals to parts, their explanations will be omitted, and only the different configurations will be explained. Explain in detail. The solenoid valve 27 incorporated in the fuel pressure regulating valve 12 of the first embodiment is connected to the fuel inlet pipe. 39, the bypass passage 28 is opened and closed on the so-called high pressure side. On the other hand, the solenoid valve 27 of this example has a bypass that communicates with the fuel discharge pipe 41. The bypass passage 28 is opened and closed on the low-pressure side, that is, on the low-pressure side.

[0020] [Example 3] Example 3 of the present invention will be described. A cross-sectional view of the vapor lock prevention device of this example is shown in Figure 4. It is shown in This example is a partial modification of Example 2, so the main points are the same. By assigning the same reference numerals to parts, their explanations will be omitted, and only the different configurations will be explained. Explain in detail. In the second embodiment, the solenoid valve 27 is integrated into the fuel pressure regulating valve 12. In contrast, in this example, the solenoid valve 27 is provided separately from the fuel pressure regulating valve 12. Therefore, the fuel return passage 1 is opened from the middle of the fuel passage 11 leading to the fuel pressure regulating valve 12. A bypass passage 28 that connects to the middle of 4 is formed by branch piping, and the bypass A solenoid valve 27 is installed in the middle of the passage 28.

[0021] Note that the present invention is not limited to the above-mentioned embodiments, and may be used without departing from the gist of the present invention. Changes within a wide range are possible.

[0022]

[Effect of the idea]

According to the present invention, the solenoid valve opens for a predetermined period of time when the engine starts, thereby reducing the fuel consumption. The fuel remaining in the fuel passage is returned to the fuel tank for a certain period of time regardless of the fuel temperature. Unlike conventional fuel temperature dependent fuel temperature, the Engine starting performance is improved.

[Brief explanation of drawings]

FIG. 1 is a schematic configuration diagram of an engine fuel supply system according to a first embodiment.

FIG. 2 is a sectional view of the vapor lock prevention device.

FIG. 3 is a sectional view of the vapor lock prevention device of Example 2.

FIG. 4 is a sectional view of the vapor lock prevention device of Example 3.

FIG. 5 is a sectional view of a conventional fuel pressure regulating valve.

[Explanation of symbols]

11 Fuel passage 12 Fuel pressure regulating valve 14 Fuel return passage 27 Solenoid valve 28 Bypass passage

Claims (1)

[Scope of utility model registration request] Claim 1: A fuel passage that sends pressurized fuel from a fuel pump to a fuel injection valve, and a fuel passage that adjusts fuel pressure by returning the pressurized fuel in the fuel passage to a fuel return passage that communicates with a fuel tank. The fuel pressure regulating valve is characterized by comprising a pressure regulating valve, a bypass passage that bypasses the valve opening/closing part of the fuel pressure regulating valve, and a solenoid valve that is provided in the middle of the bypass passage and is opened for a predetermined period of time when the engine is started. Vapor lock prevention device.