JP5314341B2 - Replacement alarm system for fuel pumps containing alcohol - Google Patents

Description

  The present invention relates to a fuel pump replacement alarm system that is mounted in a fuel tank and pumps alcohol-containing fuel to an engine.

  In recent years, a system capable of simultaneously using alcohol as an alternative fuel in addition to conventional gasoline has been put into practical use due to demands such as deterioration of fuel conditions and exhaust purification. A vehicle such as an automobile (FFV) equipped with this system (FFV: Flexible Fuel Vehicle) can run not only with gasoline but also with a mixed fuel of alcohol and gasoline, or with alcohol alone. The alcohol concentration (content rate) of the fuel used in the FFV varies between 0% (gasoline only) and 100% (alcohol only) according to the user's request when fuel is supplied to the fuel tank. In this type of FFV engine, for example, as the alcohol concentration in the fuel increases, it is difficult to vaporize at low temperatures due to the characteristics of the alcohol fuel, and the fuel injection amount of the engine is variably controlled based on the alcohol concentration detected by the alcohol concentration sensor. ing.

  On the other hand, the fuel pump that supplies fuel to the engine is an in-tank pump that is mounted inside the fuel tank, and the entire fuel pump can be immersed in the fuel.

  In this fuel pump, a pump portion and a motor portion are disposed in a case where a suction port and a discharge port are formed, and a fuel passage is formed. A positive electrode terminal and a negative electrode terminal to which electric power to be a driving source of the motor unit is supplied from the outside are assembled, and a brush that contacts the commutator of the motor unit is connected to the positive electrode terminal and the negative electrode terminal via a pigtail or the like. Then, power is supplied from the outside to the positive terminal and the negative terminal, power flows to the brush via the pigtail, etc., power is supplied from the brush to the armature coil via the commutator, and the motor unit is driven, The pump is driven by the unit, and the fuel in the fuel tank is sucked from the suction port and pumped toward the discharge port through the fuel passage.

  In this type of fuel pump, current-carrying parts such as both positive and negative terminals, pigtails and brushes are exposed in the fuel passage and exposed to the fuel. Alcohol, which is a gasoline alternative fuel, contains highly conductive components, and electrochemical corrosion (hereinafter referred to as electrolytic corrosion) occurs in the current-carrying part on the anode side exposed to the fuel containing the highly conductive alcohol. There is a concern that a current-carrying failure of the current-carrying part may be caused by an increase in current-carrying resistance due to thinning of the current-carrying part due to electrolytic corrosion.

  As countermeasures, various fuel pumps have been proposed that suppress electrolytic corrosion by reducing the exposure of conductive parts exposed to fuel. For example, Patent Document 1 and Patent Document 2 propose a fuel pump that suppresses electrolytic corrosion of both terminals by molding the positive terminal and the negative terminal with resin to reduce the exposed area of both terminals in the fuel passage. Has been.

JP 2008-64029 A JP 2008-64030 A

  According to Patent Document 1 and Patent Document 2, by molding the positive electrode terminal and the negative electrode terminal with resin, the exposed areas of both terminals exposed in the fuel passage are reduced, and the portions of both terminals subjected to electrolytic corrosion can be suppressed.

  However, it is difficult to completely cover the sliding contacts such as brushes that contact the rotating commutator and the movable wiring parts such as pigtails, and the fuel pumps accompany electrolytic corrosion of the current-carrying parts such as pigtails and brushes that are exposed to fuel. Maintenance such as replacement is required.

  The electrolytic corrosion of the current-carrying part is accelerated by energization of the current-carrying part due to the phenomenon that the metal in the current-carrying part is ionized and dissolves in the alcohol-containing fuel that is the electrolyte solution, and the rate of progress of electrolytic corrosion varies depending on the alcohol concentration of the fuel. For this reason, it is extremely difficult to set an optimal fuel pump replacement timing in an FFV in which the alcohol concentration of the fuel changes variously.

  Here, the inventor estimated the endurance life of the current-carrying part of the fuel pump based on the change in corrosion behavior, such as the change in current-carrying resistance of the current-carrying part due to the electrolytic corrosion of the current-carrying part exposed to fuel, through earnest research experiments. Found to get.

  Accordingly, an object of the present invention made in view of such a point is that for an alcohol-containing fuel that can prevent malfunction of the fuel pump by encouraging replacement of the fuel pump at an optimal timing based on the change in corrosion behavior of the current-carrying portion of the fuel pump. It is to provide a fuel pump replacement warning system.

The invention of the replacement alarm system for a fuel pump for an alcohol-containing fuel according to claim 1 that achieves the above object is provided in a case in which a suction port and a discharge port are formed in a fuel tank. And a motor unit and a pump unit which are supplied with electric power by an energizing unit exposed in the fuel channel are disposed, and the fuel sucked from the suction port is sent from the discharge port to the engine via the fuel pipe. In the replacement alarm system for the alcohol-containing fuel pump to be supplied, the system includes alcohol concentration detection means for detecting the alcohol concentration of the fuel and energization time measurement means for detecting the operation time of the fuel pump, and the energization for each of the various alcohol concentrations of the fuel. Detection of the alcohol concentration with reference to a database showing the rate of change in corrosion behavior caused by electrochemical corrosion Called for progress of the corrosion behavior change based on the detected operating time by detecting the alcohol concentration and energization time measurement means by stages, the warning means before exceeding the normal use allowable range of the fuel pump the corrosion behavior change value is set in advance It is operated.

  According to the present invention, the corrosion behavior based on the detected alcohol concentration by the alcohol concentration detection means and the detected operation time by the energization time measurement means with reference to the database showing the progress rate of electrolytic corrosion with respect to the current-carrying part for each alcohol concentration of various fuels Since the alarm means is activated before the corrosion behavior change value exceeds the normal use allowable range, the warning means informs the user that the service life of the fuel pump will be reached at an optimal timing. The fuel pump can be exchanged.

According to a second aspect of the present invention, in the replacement alarm system for the alcohol-containing fuel pump according to the first aspect , the alcohol concentration detecting means also has an alcohol concentration detecting means for controlling the engine of the FFV.

  According to the present invention, since the alcohol concentration detection means in the replacement alarm system for the alcohol-containing fuel pump also has the alcohol concentration detection means for FFV engine control, the alcohol concentration detection means dedicated to the fuel pump replacement alarm system is provided. This can be omitted, and the structure can be simplified and the manufacturing cost can be reduced.

  According to the present invention, the alarm means is activated before the change in the corrosion behavior of the current-carrying part of the fuel pump that is exposed to the alcohol-containing fuel and progresses due to electrolytic corrosion exceeds the preset normal allowable operating range of the fuel pump. The warning means can inform the user that the service life of the fuel pump will be reached at an appropriate timing, and malfunction of the fuel pump can be prevented beforehand.

A reference example and an embodiment of a replacement alarm system for an alcohol-containing fuel pump according to the present invention will be described by taking an in-tank type fuel pump in which a fuel pump is disposed in a fuel tank mounted on an FFV as an example.

(First Reference Example )
A first reference example of the present invention will be described with reference to FIGS. FIG. 1 is a configuration diagram showing an outline of a fuel pump replacement alarm system in this reference example .

  A fuel pump 5 is mounted inside the fuel tank 1, and the entire fuel pump 5 can be immersed in the fuel. The fuel tank 1 is supplied with not only gasoline but also a mixed fuel of alcohol and gasoline, or only alcohol, and the alcohol concentration of the fuel varies between 0% (gasoline only) and 100% (alcohol only).

  The fuel pump 5 is the same as a well-known existing fuel pump and will not be described in detail. However, a pump unit (not shown) is provided inside the case 6 in which the discharge port 8 connected to the suction port 7 and the fuel pipe 9 is formed. In addition, the motor unit is disposed, a fuel passage is formed, and an energization unit for the motor unit is provided. The energization unit is connected to a positive terminal and a negative terminal to which power as a driving source of the motor unit is supplied from the outside, and a brush that contacts the commutator via a pigtail or the like to the positive terminal and the negative terminal. Then, power is supplied from the outside to the positive terminal and the negative terminal, power flows to the brush via the pigtail, etc., power is supplied from the brush to the armature coil via the commutator, and the motor unit is driven, The pump is driven by this unit, the fuel in the fuel tank 1 is sucked from the suction port 7, pumped to the discharge port 8 through the fuel passage, and supplied to the engine 10 through the fuel pipe 9.

  Furthermore, an ammeter 11 serving as a current detecting means for detecting a change in energization resistance of the energization part, which becomes a corrosion behavior change that develops along with the electrolytic corrosion of the energization part in the fuel pump 5, for example, an instrument panel in the passenger compartment. The warning lamp 12 serving as a warning means provided, the current value detected by the ammeter 11 is set to a predetermined threshold value a, that is, the function of the fuel pump 5 is less than the normal use allowable range due to thinning of the current-carrying part due to electrolytic corrosion. ECU13 used as the control part which operates the warning lamp 12 when the electric current value just before becomes is provided.

  Here, the current-carrying part of the fuel pump 5 that is exposed to the alcohol-containing fuel is gradually reduced in thickness due to the electrolytic corrosion being promoted by the current-carrying with the use of the fuel pump 5, and the current value of the current-carrying part gradually increases. Gradually descend. The progress of electrolytic corrosion of the current-carrying part is estimated from the change in the current value that decreases as the current-carrying resistance increases. The threshold value a is defined as the current value immediately before the current value decreases due to the increase in the energization resistance of the energization unit and the function of the fuel pump 5 is below the normal use allowable range, that is, the service life of the fuel pump 5 is reached. This threshold value a is set in advance by experimenting or simulating the correlation between the change in the current value due to electrolytic corrosion of the current-carrying portion and the normal use allowable range.

  FIG. 2 shows an example of the correlation between the change in the current value with the passage of time of use of the fuel pump 5 and the threshold value a, that is, the lighting of the warning lamp 12.

  In the fuel pump replacement alarm device configured as described above, the current-carrying portion of the fuel pump 5 exposed to the alcohol-containing fuel in the fuel tank 1 by the operation of the FFV or the like is gradually reduced in thickness due to the electrolytic corrosion being accelerated with the current flow. When the current value of the current-carrying part detected by the ammeter 11 reaches a preset threshold value a, the corrosion behavior change value of the current-carrying part that is developed and estimated by the progress change of the current value in the current-carrying part, The warning light 12 is operated by the ECU 13 to inform the user that the service life of the fuel pump 5 is reached, and to prompt the user to replace the fuel pump 5.

Therefore, according to the present reference example , the warning lamp 12 is turned on based on a change in the current value which is a corrosion behavior change value of the current-carrying portion of the fuel pump 5 that is electrolytically corroded when exposed to the alcohol-containing fuel. Regardless of the change in the alcohol concentration, the user can be informed that the fuel pump 5 is at the end of its service life at the optimal timing, and can be urged to replace the fuel pump 5 to prevent malfunction of the fuel pump 5 in advance. it can.

(Second reference example )
A second reference example will be described with reference to FIGS. FIG. 3 is a block diagram showing an outline of the fuel pump replacement alarm system in this reference example . 3, parts corresponding to those in FIG. 1 are denoted by the same reference numerals, and detailed description thereof is omitted, and different parts are mainly described.

As in the first reference example , a fuel pump 5 is mounted in the fuel tank 1, and the fuel pump 5 is a pump (not shown) inside a case 6 in which a suction port 7 and a discharge port 8 connected to the fuel pipe 9 are formed. And a fuel passage are formed, and a pump portion is driven by the motor portion to suck the fuel in the fuel tank 1 from the suction port 7 and pump it toward the discharge port 8 through the fuel passage. Then, the fuel is supplied from the discharge port 8 to the engine 10 through the fuel pipe 9.

Further, a flow meter 21 serving as a discharge amount detecting means for detecting a change in the discharge amount of the fuel pump 5 due to a current drop of the current portion due to the electrolytic corrosion of the current-carrying portion in the fuel pump 5 as a corrosion behavior change is a fuel supply circuit, In this reference example , the fuel pipe 9 is provided. The flow rate value detected by the flow meter 21 is set to a predetermined threshold value b, that is, the discharge amount in which the current decreases due to the increase in the current resistance due to the thinning of the energized part due to electrolytic corrosion and the fuel pump 5 progresses and changes is normally used. An ECU 23 is provided as a control unit that turns on the warning lamp 12 when the flow rate value immediately before the permissible range or less is set as a threshold value b and the threshold value b is exceeded.

  Here, the current-carrying part of the fuel pump 5 that is exposed to the alcohol-containing fuel is gradually reduced in thickness due to the electrolytic corrosion being promoted by energization associated with the use of the fuel pump 5, and the current-carrying resistance of the current-carrying part gradually increases to increase the current value. descend. As the current value decreases, the fuel pump 5 gradually decreases the discharge amount. The progress change of the discharge amount of the fuel pump 5 is regarded as a change in corrosion behavior, and the change in corrosion of the energized portion is estimated by the change in the discharge amount of the fuel pump 5 that becomes the corrosion behavior change value. Is the normal use allowable range, that is, the discharge amount of the fuel pump 5 immediately before the endurance life of the fuel pump 5 is assumed to be the threshold value b. This threshold value b is set in advance based on simulations and experiments on the correlation between the change in progress of the discharge amount of the fuel pump 6 due to electrolytic corrosion of the current-carrying portion and the normal allowable use range of the fuel pump 5.

  FIG. 4 shows the correlation between the change in the discharge amount of the fuel pump 5 and the threshold value b, that is, the lighting of the warning lamp 12.

  In the fuel pump replacement alarm system configured as described above, the conductive portion of the fuel pump 5 exposed to the alcohol-containing fuel in the fuel tank 1 by the operation of the FFV or the like is gradually reduced in thickness due to the electrolytic corrosion being promoted with energization. The flow rate of the fuel pump 5 is changed by the flow meter 21. When the discharge amount value of the fuel pump 5 by the flow meter 21 serving as the corrosion behavior change value reaches a preset threshold value b, the warning light 12 is operated by the ECU 23 to let the user know the service life of the fuel pump 5. It is informed that the fuel pump 5 is about to be replaced.

Therefore, according to the present reference example , the warning lamp 12 is turned on based on the progress change of the discharge amount of the fuel pump 5 that changes with the electrolytic corrosion of the conductive portion of the fuel pump 5 exposed to the alcohol-containing fuel. Regardless of the change in alcohol concentration, the user can be notified of the fact that the fuel pump 5 has reached the endurance life at an optimal timing, and can be urged to replace the fuel pump 5.

( Embodiment )
The embodiment will be described with reference to FIGS. FIG. 5 is a configuration diagram showing an outline of the fuel pump replacement alarm system in the present embodiment. In FIG. 5, parts corresponding to those in FIG. 1 are denoted by the same reference numerals, and detailed description thereof is omitted, and different parts are mainly described.

Similar to the first reference example and the second reference example , a fuel pump 5 is mounted in the fuel tank 1, and the fuel pump 5 has a case 6 in which a discharge port 8 connected to a suction port 7 and a fuel pipe 9 is formed. A pump part and a motor part (not shown) are arranged inside, and a fuel passage is formed. The pump part is driven by the motor part to suck in fuel from the suction port 7 and pump it to the discharge port 8 through the fuel passage. Then, the fuel is supplied to the engine 10 through the fuel pipe 9.

  An alcohol concentration sensor 31 that is an alcohol concentration detection means for detecting the alcohol concentration of the fuel in use provided in a fuel supply circuit such as the fuel pipe 9 and an energization time measuring means 32 for detecting the energization time of the fuel pump 5; Further, based on the alcohol concentration detected by the alcohol concentration sensor 31 and the developed corrosion behavior change value obtained by the energization time detected by the energization time measuring means 32, the warning lamp 12 immediately before the fuel pump 5 reaches the service life. ECU33 which becomes a control part which carries out lighting operation of is provided.

  Here, in the FFV, the alcohol concentration of the fuel being used is detected by the alcohol concentration sensor and the engine is controlled, so that the alcohol concentration sensor for engine control can be used as the alcohol concentration sensor 31 of the present embodiment. it can. FIG. 6 shows an example of the correlation between the endurance time of the electrolytic corrosion of the current-carrying part of the fuel pump 5 with respect to various alcohol concentrations of the fuel, that is, the endurance time of the fuel pump 6 due to the thinning due to the electrolytic corrosion of the current-carrying part. Show. The development ratio of the conductive portion due to electrolytic corrosion per unit time for each of various alcohol concentrations is stored in the control unit 33 and stored in the control unit 33. The alcohol concentration detected by the alcohol detection sensor 31 in the control unit 33 and the energization time measuring means 32 are stored. Corrosion behavior change of the current-carrying part based on the database showing the progress rate of the electro-corrosion corrosion of the conductive part for each alcohol concentration based on the energization time at each alcohol concentration detected by Calculate the value. When the corrosion behavior change value reaches a preset threshold value c, the ECU 33 activates the warning lamp 12.

  This threshold value c is set in advance by simulation or experiment to correlate with a change value of corrosion behavior that changes due to electrolytic corrosion of the conductive portion depending on the alcohol concentration of the fuel and the operation time. FIG. 7 shows the correlation between the corrosion behavior change value and the threshold value c, that is, the lighting of the warning lamp 12.

  In the fuel pump replacement alarm device configured as described above, the conductive portion of the fuel pump 5 exposed to the alcohol-containing fuel in the fuel tank 1 due to the operation of the FFV or the like is gradually reduced due to the electric corrosion caused by the energization. When the corrosive behavior change value, which is calculated based on the alcohol concentration of the fuel used and the usage time, reaches a predetermined threshold value c, the warning light 14 is activated by the ECU 33. Thus, the user can be informed that the service life of the fuel pump 5 will be reached, and the user will be notified that the fuel pump 5 will be in service life at an optimal timing, and can be urged to replace the fuel pump 5.

The present invention is not limited to the form of the above you facilities, various modifications are possible without departing from the scope of the invention. For example, using the alarm lamp as an alarm means in the form of the above you facilities, it is also possible to use a buzzer other alarm means.

It is a block diagram which shows the outline | summary of the fuel pump exchange warning system in a 1st reference example . It is a figure which shows the correlation of the usage time of a fuel pump, and the change of the electric current value of an electricity supply part. It is a block diagram which shows the outline | summary of the fuel pump replacement | exchange warning system in a 2nd reference example . It is a figure which shows the correlation of the usage time of a fuel pump, and discharge amount. Is a block diagram showing an outline of a fuel pump replacement warning system in the form of implementation. It is a figure which shows the correlation with the alcohol concentration of each fuel, and the durable time of a fuel pump. It is a figure which shows the correlation with the use time of a fuel pump, and a corrosion behavior change value.

DESCRIPTION OF SYMBOLS 1 Fuel tank 5 Fuel pump 6 Case 7 Inlet 8 Discharge 9 Fuel pipe 10 Engine 11 Ammeter (current detection means)
12 Warning light (alarm means)
13 ECU (control unit)
21 Flow meter (Discharge rate detection means)
23 ECU (control unit)
31 Alcohol concentration sensor (alcohol concentration detection means)
32 energization time measuring means 33 ECU (control unit)

Claims (2)

A motor unit that is mounted in the fuel tank and in which a suction port and a discharge port are formed, a fuel passage that connects the suction port and the discharge port is formed, and a motor unit that is supplied with power by an energization unit that is exposed to the fuel passage In the replacement alarm system for the alcohol-containing fuel pump, in which the pump unit is disposed and the fuel sucked from the suction port is supplied to the engine from the discharge port through the fuel pipe,
Comprising alcohol concentration detection means for detecting the alcohol concentration of fuel and energization time measurement means for detecting the operation time of the fuel pump;
The detected alcohol concentration by the alcohol concentration detecting means and the detection operation time by the energizing time measuring means with reference to a database showing the progress rate of the corrosion behavior change caused by electrochemical corrosion of the current-carrying part for each alcohol concentration of the fuel Replacement of the alcohol-containing fuel pump , wherein the progress of the corrosion behavior change is obtained based on the above and the alarm means is activated before the corrosion behavior change value exceeds a preset normal use allowable range of the fuel pump Alarm system. 2. The alcohol replacement fuel pump replacement alarm system according to claim 1 , wherein the alcohol concentration detection means also serves as alcohol concentration detection means for FFV engine control.

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