JP2007120413A - Internal combustion engine - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an internal combustion engine capable of putting mixed fuel stored in a fuel tank under homogeneous mix condition while inhibiting consumption of excess energy. <P>SOLUTION: The engine is provided with a fuel tank 1 storing mixed fuel mixing alcohol AL and gasoline GA and fuel mixing device 12 mixing the mixed fuel stored in the fuel tank 1, and ECU 20 determines necessity of mixing of the mixed fuel based on a mixing condition of the mixed fuel stored in the fuel tank 1. The ECU 20 operates the fuel mixing device 12 when the engine stops and the ECU determines that mixing of the mixed fuel is necessary. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to an internal combustion engine using a mixed fuel in which a plurality of fuels such as gasoline and alcohol are mixed.

  It is known that a mixed fuel that is a mixture of gasoline and alcohol is likely to cause phase separation of gasoline and alcohol when the alcohol concentration is low, when the mixed fuel contains more than a certain amount of water, or at low temperatures. Yes. Further, when a mixed fuel having a different alcohol concentration from the mixed fuel stored in the fuel tank is supplied to the fuel tank, the alcohol concentration of the mixed fuel stored in the fuel tank may be non-uniform. When the alcohol concentration is not uniform or when the gasoline and alcohol are phase-separated, the mixed fuel having a stable property cannot be supplied, so that the combustion of the internal combustion engine may become unstable. Therefore, in an internal combustion engine using such a mixed fuel, the alcohol concentration in the mixed fuel detected at the start of the internal combustion engine is compared with the alcohol concentration in the mixed fuel when the internal combustion engine was last stopped. There is known an internal combustion engine that premixes fuel by operating a fuel pump when the fuel pressure changes (see Patent Document 1). There is also known an internal combustion engine in which a fuel tank is provided with a stirring device that stirs the mixed fuel stored in the fuel tank (see Patent Document 2).

JP-A-6-26414 Japanese Utility Model Publication No. 7-17799

  In the internal combustion engine of Patent Document 1, the mixed fuel stored in the fuel tank is stirred by circulating through the fuel passage. In order to circulate the mixed fuel in this way, it is necessary to raise the mixed fuel above the set pressure of the pressure regulator provided in the fuel passage. Therefore, extra energy is consumed for stirring the mixed fuel. Patent Document 2 does not disclose any control method for the stirring device provided in the fuel tank.

  SUMMARY OF THE INVENTION An object of the present invention is to provide an internal combustion engine capable of bringing a mixed fuel stored in a fuel tank into a substantially uniform mixed state while suppressing consumption of excess energy.

  An internal combustion engine according to the present invention includes a fuel tank that stores a mixed fuel obtained by mixing a plurality of fuels, a stirring unit that stirs the mixed fuel stored in the fuel tank, and a mixed fuel stored in the fuel tank. And an agitation determination means for determining the necessity of agitation of the mixed fuel based on a mixed state, and determines that the agitation of the mixed fuel is necessary by the agitation determination means when the internal combustion engine is stopped. In this case, the above-described problem is solved by providing an operation control means for operating the stirring means.

  During operation of the internal combustion engine, a flow occurs in the mixed fuel in the fuel tank, such as sucking up the mixed fuel stored in the fuel tank to supply fuel from the fuel tank to the engine body. The mixed fuel is stirred. In the internal combustion engine of the present invention, the mixed fuel in the fuel tank is agitated by the agitating means when the internal combustion engine is stopped and the agitation of the mixed fuel in the fuel tank is necessary. The consumed energy can be suppressed and the mixed fuel can be brought into a substantially uniform mixed state in the fuel tank.

  In addition, the concept of “uniform” in the present invention is the case where the mixture ratio of the mixed fuel stored in the fuel tank is the same in the entire mixed fuel, and the case where the mixed fuel stored in the fuel tank is different from each other. This includes both cases where the difference in the mixing ratio of the mixed fuel is within the allowable range in which the internal combustion engine can be stably operated.

  In one form of the internal combustion engine of the present invention, the agitation determination means includes phase separation determination means for determining whether or not the mixed fuel stored in the fuel tank is phase-separated and is mixed by the phase separation determination means. When it is determined that the fuel is phase-separated, it is determined that the mixed fuel needs to be agitated, and the operation control unit eliminates the phase separation of the mixed fuel stored in the fuel tank by the phase separation determination unit. The stirring means may be operated until it is determined that it has been performed (Claim 2). Controlling the operation of the stirring means in this way can prevent useless stirring of the mixed fuel. Therefore, the energy consumed by the mixed fuel can be reduced.

  The concept of “phase separation” in the present invention is that when the light and heavy components in the mixed fuel are separated, and the concentration of the heavy components in the mixed fuel near the bottom of the fuel tank is near the oil level. This includes both cases where the separation is not performed, such as when the concentration is higher than the concentration of the heavy component of the mixed fuel, but the distribution of the mixing ratio of the mixed fuel occurs in the height direction of the fuel tank.

  One form of the internal combustion engine of the present invention includes start request determination means for determining whether or not start of the internal combustion engine is requested, and the operation control means is when the internal combustion engine is stopped and the start request determination means. If it is determined that the start of the internal combustion engine has been requested, and the agitation determination unit determines that the agitation of the mixed fuel is necessary, the agitation unit may be operated (Claim 3). In this case, since the mixed fuel is stirred immediately before the internal combustion engine is started, the mixed fuel in a substantially uniform mixed state can be supplied to the internal combustion engine while preventing unnecessary mixing of the mixed fuel.

  One aspect of the internal combustion engine of the present invention further includes a battery that supplies electric power to a device provided in a vehicle on which the internal combustion engine is mounted, and a battery remaining amount detection unit that detects a remaining amount of the battery, The stirring means is operated by the electric power supplied from the battery, and the operation control means is configured to turn the stirring means when the remaining amount of the battery detected by the battery remaining amount detecting means is equal to or greater than a preset lower limit value. It may be operated (Claim 4). In this case, it is possible to prevent the remaining amount of the battery from decreasing below the lower limit value by operating the stirring means. Therefore, it is possible to prevent the remaining amount of the battery from becoming substantially zero, and to reliably operate the device to which power is supplied from the battery.

  In one form of the internal combustion engine of the present invention, the mixed fuel may be a fuel in which gasoline and alcohol are mixed (claim 5). Further, in this embodiment, a plurality of alcohol concentration detection means for detecting the alcohol concentration of the mixed fuel stored in the fuel tank are provided in the fuel tank so that the heights thereof are different from each other, and the stirring determination means includes the It may be determined whether or not the mixed fuel stored in the fuel tank needs to be agitated by comparing the alcohol concentrations detected by the plurality of alcohol concentration detecting means provided in the fuel tank. When the mixed fuel that is a mixture of gasoline and alcohol is phase-separated, alcohol heavier than gasoline collects at the bottom of the fuel tank, so the alcohol concentration of the mixed fuel near the bottom of the fuel tank and the alcohol concentration of the mixed fuel near the oil level A difference in density occurs between them. For this reason, the alcohol concentration in the mixed fuel of different heights is detected by a plurality of alcohol concentration detection means provided at different heights in the fuel tank, and the detected alcohol concentrations are compared to store in the fuel tank. It is possible to determine whether the mixed fuel that is being mixed needs to be stirred.

  Further, one of the plurality of alcohol concentration detection means is disposed on the bottom surface of the fuel tank, and the other one of the plurality of alcohol concentration detection means is disposed on a float member provided in the fuel tank. (Claim 7). As described above, the phase-separated alcohol collects at the bottom of the fuel tank, so that the alcohol concentration near the bottom of the fuel tank is higher than the alcohol concentration near the oil level. Therefore, by arranging one of the plurality of alcohol concentration detection means on the bottom surface of the fuel tank and the other one on the float member, the phase separation of the mixed fuel can be detected quickly.

  As described above, according to the present invention, wasteful stirring by the stirring means of the mixed fuel stored in the fuel tank can be prevented, so that the mixed fuel is adjusted while maintaining the mixed fuel in a substantially uniform mixed state. Energy consumed for stirring can be reduced.

(First form)
FIG. 1 shows a fuel tank of an internal combustion engine according to the first embodiment of the present invention. An internal combustion engine (hereinafter also referred to as an engine) provided with the fuel tank 1 of FIG. 1 can be operated with a mixed fuel in which gasoline and alcohol are mixed, so-called alcohol mixed gasoline. This mixed fuel is stored. As shown in FIG. 1, the fuel tank 1 includes a fuel pump 2 that sucks mixed fuel stored in the fuel tank 1 through a strainer 3 and sends it to an engine body (not shown) of the engine, and a fuel tank. 1 outputs a fuel supply passage 4 for supplying mixed fuel, a breather passage 5 for extracting air from the fuel tank 1 during refueling, and a signal corresponding to the amount of mixed fuel stored in the fuel tank 1 The fuel amount sensor 6 is provided. The fuel pump 2 includes a return passage 7 that discharges an excess of the mixed fuel sucked from the fuel tank 1 that has not been sent to the engine body from the outlet 7a toward the bottom of the fuel tank 1a. As shown in FIG. 1, the tank side outlet 4 a of the fuel supply passage 4 is provided so that the mixed fuel flows toward the bottom of the fuel tank 1. The fuel amount sensor 6 includes a float 8 as a float member provided in the fuel tank 1, and an arm 9 having one end 9a rotatably attached to the fuel pump 2 and the other end provided with the float 8. The amount of the mixed fuel stored in the fuel tank 1 is detected by the position of the float 8 that moves together with the oil level of the mixed fuel stored in the fuel tank 1. Since these portions may be the same as those of a well-known fuel tank, detailed description thereof is omitted here.

  The fuel tank 1 is provided with alcohol concentration sensors 10 and 11 as alcohol concentration detection means for outputting a signal corresponding to the alcohol concentration of the mixed fuel, on the bottom surface 1a of the fuel tank 1 and the float 8, respectively. Hereinafter, the alcohol concentration sensor 10 provided on the bottom surface 1a of the fuel tank 1 is referred to as a first alcohol concentration sensor 10, and the alcohol concentration sensor 11 provided on the float 8 is referred to as a second alcohol concentration sensor 11. There is also. As shown in FIG. 1, the bottom surface 1 a of the fuel tank 1 is inclined so as to draw a downward slope from the side surface toward the center, and the first alcohol concentration sensor 10 provided on the bottom surface 1 a is a bottom portion of the fuel tank 1. Is arranged at the lowest position on the bottom surface 1a so as to detect the alcohol concentration of the mixed fuel collected in the bottom surface 1a. The second alcohol concentration sensor 11 provided in the float 8 is provided so as to move together with the float 8 and is attached to the float 8 so as to detect the alcohol concentration of the mixed fuel near the oil level.

  The fuel tank 1 also includes a fuel agitation device 12 as agitation means for agitating the mixed fuel stored inside. The fuel agitation device 12 includes a fuel circulation passage 13 having one end connected to the bottom surface 1 a of the fuel tank 1 and the other end connected to the ceiling surface of the fuel tank 1, and a circulation pump 14. The fuel agitation device 12 aspirates the mixed fuel in the fuel tank 1 by sucking the mixed fuel at the bottom of the fuel tank 1 by the circulation pump 14 and returning the mixed fuel from the ceiling surface of the fuel tank 1. The connection position of the other end of the fuel circulation passage 13 is not limited to the ceiling surface of the fuel tank 1, but can be stirred by circulating the mixed fuel in the fuel tank 1, and the detection accuracy of the fuel amount sensor 6 and the second You may connect to the various places which do not affect the detection accuracy of the alcohol concentration sensor 11.

  The operation of the circulation pump 14 is controlled by an engine control unit (ECU) 20. The ECU 20 is configured as a computer including a microprocessor and peripheral devices such as RAM and ROM necessary for its operation. For example, the ECU 20 controls the operation of the fuel pump 2 and the like based on an output signal of the crank angle sensor 21 and the like. It is a well-known computer unit which controls the driving | running state of. The ECU 20 is connected to first and second alcohol concentration sensors 10 and 11 as means for acquiring information necessary for controlling the operation of the circulation pump 14.

  FIG. 2 shows a flowchart of a fuel agitation control routine that the ECU 20 executes to control the operation of the circulation pump 14. The control routine of FIG. 2 is set as one of the control routines executed when the ECU 20 is activated, and is repeatedly executed at a predetermined cycle while the ECU 20 is operating even when the engine is stopped.

  In the control routine of FIG. 2, the ECU 20 first determines whether or not the engine is stopped in step S11. Whether or not the engine is stopped is determined with reference to an output signal of the crank angle sensor 21, for example. If it is determined that the engine is stopped, the process proceeds to step S12, where the ECU 20 detects the first alcohol concentration sensor 10 from the detection value of the second alcohol concentration sensor 11 (hereinafter also referred to as the upper concentration). It is determined whether or not the absolute value (hereinafter referred to as density difference) of the value obtained by subtracting the value (hereinafter also referred to as lower density) is greater than the allowable value A. As shown in FIG. 1, the phase-separated alcohol AL gathers at the bottom of the fuel tank 1, and the phase-separated gasoline GA gathers above the phase-separated alcohol AL, so that the mixed fuel near the bottom of the fuel tank 1 is mixed. The alcohol concentration of the fuel becomes higher than the alcohol concentration of the mixed fuel near the oil level. Therefore, it is determined whether the mixed fuel is phase-separated by comparing the upper concentration with the lower concentration. As the allowable value A, for example, a density difference is set such that the engine can be stably operated and the engine can be started. Such a density difference is obtained in advance by experiments or the like and stored in the ROM of the ECU 20.

  When it is determined that the concentration difference is larger than the allowable value A, the process proceeds to step S13, where the ECU 20 is in a state where the circulation pump is activated and the agitation flag indicating that the mixed fuel in the fuel tank 1 is being agitated is on. To determine. If it is determined that the stirring flag is on, the current control routine is terminated. On the other hand, if it is determined that the stirring flag is off, the process proceeds to step S14, where the ECU 20 activates the circulation pump 14. In subsequent step S15, the ECU 20 switches the stirring flag to an on state. Thereafter, the current control routine is terminated.

  If it is determined in step S11 that the engine is operating, or if it is determined in step S12 that the concentration difference is equal to or smaller than the allowable value A, the process proceeds to step S16, and the ECU 20 stops the circulation pump 14. In subsequent step S17, the ECU 20 switches the stirring flag to an off state. Thereafter, the current control routine is terminated.

  In the control routine of FIG. 2, the circulation pump 14 is operated when the engine is stopped, that is, when the fuel pump 2 is stopped and when it is determined that phase separation occurs in the mixed fuel in the fuel tank 1. Unnecessary agitation of the mixed fuel stored in the tank 1 can be prevented. Further, when it is determined that the concentration difference is reduced to the allowable value A or less and the phase separation of the mixed fuel has been eliminated, the circulation pump 14 is stopped, so that it is possible to prevent useless stirring of the mixed fuel. Therefore, the energy consumed for stirring the mixed fuel can be reduced. Thus, by executing the control routine of FIG. 2 and controlling the operation of the fuel circulation device 12, the ECU 20 functions as the operation control means of the present invention. Further, the ECU 20 functions as the phase separation determination means of the present invention by executing the process of step S12 of FIG. 2 and determining whether or not the mixed fuel in the fuel tank 1 is phase-separated. Further, the ECU 20 functions as the agitation determination means of the present invention by determining whether or not the agitation of the mixed fuel in the fuel tank 1 is necessary by executing the process of step S12.

  Since the first alcohol concentration sensor 10 is provided on the bottom surface 1a of the fuel tank 1 and the second alcohol concentration sensor 11 is provided on the float 8, the first alcohol concentration sensor 10 is provided near the bottom of the fuel tank 1 by the first alcohol concentration sensor 10. The alcohol concentration of the mixed fuel can be detected, and the alcohol concentration of the mixed fuel near the oil level can be detected by the second alcohol concentration sensor 11. Therefore, phase separation of the mixed fuel stored in the fuel tank 1 can be detected quickly.

  As shown in FIG. 1, the outlet 7 a of the return passage 7 is provided to discharge the mixed fuel toward the bottom of the fuel tank 1, so that the engine 1 is operated from the return passage 7 to the fuel tank 1 during operation of the engine 1. The mixed fuel stored in the fuel tank 1 can be agitated by the returned mixed fuel. Further, since the tank-side outlet 4a of the fuel supply passage 4 is provided so that the mixed fuel flows toward the bottom of the fuel tank 1, the mixed fuel flowing from the fuel supply passage 4 is also fueled when the mixed fuel is supplied. The mixed fuel in the tank 1 can be stirred.

  FIG. 3 shows the detected value of the first alcohol concentration sensor 10 and the detected value of the second alcohol concentration sensor 11 when the mixed fuel stored in the fuel tank 1 is stirred by executing the control routine of FIG. An example of time change is shown. Note that the line L1 in FIG. 3 shows the time change of the detection value (lower concentration) of the first alcohol concentration sensor 10, and the line L2 shows the time change of the detection value (upper concentration) of the second alcohol concentration sensor 11. Show. In FIG. 3, at time T1, the density difference drops below the allowable value A. That is, in FIG. 3, it is determined that the mixed fuel in the fuel tank 1 is phase-separated until time T1, and it is determined that the phase separation of the mixed fuel is eliminated at time T1. Therefore, in FIG. 3, the circulation pump 14 operates until time T1, and the circulation pump 14 is stopped after time T1.

  FIG. 4 is a flowchart showing a modification of the fuel agitation control routine of FIG. In FIG. 4, the same processes as those in FIG. 2 are denoted by the same reference numerals, and the description thereof is omitted. The control routine of FIG. 4 differs from the control routine of FIG. 2 in that the process of step S21 is inserted between the process of step S11 and the process of step S12. The control routine of FIG. 4 is also executed when the ECU 20 is started, similarly to the control routine of FIG. 2, and is repeatedly executed at a predetermined cycle while the ECU 20 is operating.

  In the control routine of FIG. 4, when it is determined in step S11 that the engine is stopped, the process proceeds to step S21, and the ECU 20 determines whether or not the engine is requested to start. It is determined that the engine is started when, for example, the ignition key is turned to a predetermined start position. Also, in a so-called eco-run vehicle that stops the engine when a predetermined engine stop condition is satisfied while the engine is operating, the accelerator is operated by the driver when the predetermined engine stop condition is satisfied and the engine is stopped. It is determined that the engine is requested to start even when the pedal or the shift gear is operated. If it is determined that the engine has been requested to start, the process proceeds to step S12, and processing similar to that of the control routine of FIG. Thereafter, the current control routine is terminated. On the other hand, if it is determined that the engine start is not requested, the process proceeds to step S16, and after executing the processes of steps S16 and S17, the current control routine is terminated.

  In the control routine of FIG. 4, the circulation pump 14 is started when it is determined that the engine is required to be started when the engine is stopped and the mixed fuel in the fuel tank 1 is phase-separated. . By operating the circulation pump 14 in this way, the mixed fuel can be stirred immediately before the engine is started. Therefore, it is possible to quickly supply the mixed fuel that is not phase-separated to the engine while preventing useless stirring of the mixed fuel. Note that the ECU 20 functions as a start request determination unit of the present invention by executing the process of step S21 of FIG.

(Second form)
FIG. 5 shows a fuel tank 1 of an internal combustion engine according to the second embodiment of the present invention. 5 that are the same as those in FIG. 1 are given the same reference numerals, and descriptions thereof are omitted. An internal combustion engine (engine) provided with the fuel tank 1 of FIG. 5 includes a motor generator (not shown) that can function as a generator that generates power using the output of the engine and an electric motor that assists the output of the engine. The battery 30 is connected to the motor generator, and is mounted on a hybrid vehicle including an SOC (State of Charge) sensor 31 as a battery remaining amount detecting means for outputting a signal corresponding to the remaining amount of the battery 30. Is done. As shown in FIG. 5, the circulation pump 14 is connected to the battery 30 and operates with electric power supplied from the battery 30. The fuel tank 1 stores a mixed fuel obtained by mixing gasoline and alcohol as in the first embodiment.

  FIG. 6 is a flowchart showing a fuel agitation control routine executed by the ECU 20 of FIG. The control routine of FIG. 6 is also executed when the ECU 20 is started, similarly to the control routine of FIG. 2, and is repeatedly executed at a predetermined cycle during the operation of the ECU 20. In the control routine of FIG. 6, the same processes as those of the control routine of FIG.

  In the control routine of FIG. 6, the ECU 20 first determines in step S31 whether or not the vehicle is parked. Whether or not the vehicle is parked is determined based on, for example, the state of an automatic transmission or a parking brake provided in the vehicle. If it is determined that the vehicle is not parked, the process proceeds to step S11, and thereafter the same processing as in the control routine of FIG. 2 is executed. Thereafter, the current control routine is terminated.

  On the other hand, when it is determined that the vehicle is parked, the process proceeds to step S <b> 32, and the ECU 20 determines whether or not the charging state of the battery 30 is good. The state of charge of the battery 30 is determined with reference to the output signal of the SOC sensor 31 and determined to be good when the remaining amount of the battery 30 is equal to or greater than a preset lower limit value so as not to hinder the operation of the vehicle. When it is determined that the state of charge of the battery 30 is not good, that is, the remaining amount of the battery 30 is less than the lower limit value, the process proceeds to step S16, and the ECU 20 executes the process of step S16 and step S17, and then the current control routine Exit.

  When it is determined that the state of charge of the battery 30 is good, that is, the remaining amount of the battery 30 is greater than or equal to the lower limit value, the process proceeds to step S33, and the ECU 20 determines whether the concentration difference is greater than the determination value B. The determination value B is set to a value larger than the allowable value A. For example, a concentration difference that can shorten the time for stirring the mixed fuel in the fuel tank 1 when the engine is started is set. If it is determined that the density difference is larger than the determination value B, the process proceeds to step S13, and the same processing as in FIG. Thereafter, the current control routine is terminated. On the other hand, if it is determined that the density difference is equal to or less than the determination value B, the process proceeds to step S16, and the ECU 20 executes the processes of steps S16 and S17, and then ends the current control routine.

  In the internal combustion engine of the second embodiment, the mixed fuel in the fuel tank 1 is agitated by operating the circulation pump 14 even when phase separation of the mixed fuel is detected while the vehicle is parked. The time for stirring can be shortened. Further, if the ECU 20 is operating, the mixed fuel in the fuel tank 1 can be stirred before the driver gets on. In this control routine, when the remaining amount of the battery 30 is less than the lower limit value, the fuel agitating device 12 is stopped. Therefore, the remaining amount of the battery 30 is prevented from becoming substantially zero, and electric power is supplied from the battery 30. Devices such as motor generators can be operated reliably.

  The present invention is not limited to the above-described form and can be implemented in various forms. For example, the mixed fuel used in the internal combustion engine of the present invention is not limited to alcohol mixed gasoline in which alcohol and gasoline are mixed. A mixed fuel in which a plurality of fuels for phase separation are mixed may be used. In this case, when the mixed fuel is phase-separated, the light components in the mixed fuel are gathered up and the heavy components are gathered down, so that the mixing ratios of the mixed fuels at different heights of the fuel tank are different. Therefore, it is possible to quickly determine whether or not the mixing ratio of the mixed fuel is uniform by providing means for detecting the mixing ratio so that the fuel tanks have different heights.

  The position where the alcohol concentration sensor is provided in the fuel tank is not limited to the float and the bottom surface. For example, a plurality of alcohol concentration sensors may be provided on the side surface of the fuel tank so that the alcohol concentration of the mixed fuel in the fuel tank can be detected and the heights are different from each other. Further, the number of alcohol concentration sensors provided in the fuel tank is not limited to two. Three or more alcohol concentration sensors may be provided in the fuel tank so as to have different heights.

The figure which shows the fuel tank of the internal combustion engine which concerns on the 1st form of this invention. The flowchart which shows the fuel stirring control routine which ECU of FIG. 1 performs. FIG. 2 shows an example of the time change of the detection value of the first alcohol concentration sensor and the detection value of the second alcohol concentration sensor when the mixed fuel stored in the fuel tank is stirred by executing the control routine of FIG. Figure. The flowchart which shows the modification of the fuel stirring control routine which ECU of FIG. 1 performs. The figure which shows the fuel tank of the internal combustion engine which concerns on the 2nd form of this invention. The flowchart which shows the fuel stirring control routine which ECU of FIG. 5 performs.

Explanation of symbols

1 Fuel tank 1a Bottom surface 8 Float (float member)
10 first alcohol concentration sensor (alcohol concentration detection means)
11 Second alcohol concentration sensor (alcohol concentration detection means)
12 Fuel stirrer (stirring means)
20 Engine control unit (stirring determination means, operation control means, phase separation determination means, start request determination means)
30 battery 31 SOC sensor (battery remaining amount detection means)
GA Gasoline AL Alcohol

Claims (7)

This mixing based on the mixed state of the fuel tank that stores the mixed fuel obtained by mixing a plurality of fuels, the stirring means that stirs the mixed fuel stored in the fuel tank, and the mixed fuel stored in the fuel tank In an internal combustion engine provided with stirring determination means for determining whether or not fuel stirring is required,
An internal combustion engine comprising operation control means for operating the agitation means when the internal combustion engine is stopped and when the agitation determination means determines that agitation of the mixed fuel is necessary. The agitation determination means includes phase separation determination means for determining whether or not the mixed fuel stored in the fuel tank is phase-separated, and is determined that the mixed fuel is phase-separated by the phase separation determination means. If it is determined that the mixed fuel needs to be stirred,
The operation control means operates the agitation means until it is determined by the phase separation determination means that phase separation of the mixed fuel stored in the fuel tank has been eliminated. Internal combustion engine. Starting request determining means for determining whether or not starting of the internal combustion engine is requested,
The operation control means is when the internal combustion engine is stopped, it is determined that the start request determination means has requested the start of the internal combustion engine, and the agitation determination means determines that the mixed fuel needs to be stirred. The internal combustion engine according to claim 1 or 2, wherein the stirring means is operated. A battery for supplying electric power to a device provided in a vehicle on which the internal combustion engine is mounted; and a battery remaining amount detecting means for detecting a remaining amount of the battery;
The stirring means is operated by electric power supplied from the battery,
The said operation control means operates the said stirring means, when the remaining amount of the said battery detected by the said battery remaining amount detection means is more than the preset lower limit. An internal combustion engine according to claim 1.   The internal combustion engine according to any one of claims 1 to 4, wherein the mixed fuel is a fuel in which gasoline and alcohol are mixed. A plurality of alcohol concentration detection means for detecting the alcohol concentration of the mixed fuel stored in the fuel tank are provided in the fuel tank so as to have different heights,
The agitation determination means determines whether or not the agitation of the mixed fuel stored in the fuel tank is necessary by comparing the alcohol concentrations detected by the plurality of alcohol concentration detection means provided in the fuel tank. The internal combustion engine according to claim 5, characterized in that:   One of the plurality of alcohol concentration detection means is disposed on the bottom surface of the fuel tank, and the other one of the plurality of alcohol concentration detection means is disposed on a float member provided in the fuel tank. The internal combustion engine according to claim 6.

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