JP2009276091A - Detecting device of residual quantity of fuel - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a detecting device of a residual quantity of fuel which can properly detect the residual quantity of fuel. <P>SOLUTION: This device includes a level sensor 28 which is applied to a vehicle 10 provided with a fuel tank 12 for storing the fuel and detects a liquid level height of the fuel in the fuel tank 12. The residual quantity of the fuel in the fuel tank 12 is detected based on an output signal of the level sensor 28. In the running of the vehicle 10, detection of the residual quantity of the fuel based on the output signal of the level sensor 28 is permitted when detecting conditions that an absolute value of acceleration of the vehicle 10 is smaller than a prescribed value and that a steering angle of the vehicle is smaller than a prescribed angle. The detection of the residual quantity of the fuel based on the output signal of the level sensor 28 is prohibited when the detecting conditions are unestablished. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a fuel remaining amount detection device that detects the remaining amount of fuel stored in a fuel tank.

Usually, a vehicle such as an automobile is provided with a fuel tank, and fuel supplied to an internal combustion engine provided as a drive source of the vehicle is stored in the fuel tank. As a fuel remaining amount detecting device for detecting the remaining amount of fuel in the fuel tank, a level sensor for detecting the liquid level (liquid level) of the fuel stored in the fuel tank (For example, refer to Patent Document 1). In this apparatus, the remaining amount of fuel in the fuel tank is obtained based on the output signal of the level sensor.
JP-A-1-15616

  Here, when the vehicle travels, the fuel in the fuel tank moves due to acceleration / deceleration or turning of the vehicle, a change in the inclination angle of the traveling road surface, and the liquid level of the fuel is shaken. In the fuel remaining amount detection device, when the fuel level in the fuel tank fluctuates in this way, the output signal of the level sensor fluctuates accordingly. It becomes impossible to detect, and this causes a decrease in detection accuracy of the remaining amount of fuel.

  Incidentally, by adopting a detection method that prohibits detection of the remaining amount of fuel through the level sensor while the vehicle is running, it is possible to improve the detection accuracy of the remaining amount of fuel. However, in this case, since the detection of the remaining amount of fuel is permitted only when the vehicle is stopped, the period during which the remaining amount of fuel can be detected becomes extremely short. For this reason, an apparatus that employs the above detection method cannot appropriately monitor the remaining amount of fuel at that time.

  The present invention has been made in view of such circumstances, and an object of the present invention is to provide a fuel remaining amount detecting device capable of properly detecting the remaining amount of fuel.

Hereinafter, means for achieving the above-described object and its operation and effects will be described.
The invention according to claim 1 is applied to a vehicle provided with a fuel tank for storing fuel, and includes a level sensor for detecting a liquid level of the fuel in the fuel tank, and an output signal of the level sensor. In the fuel remaining amount detecting device for detecting the remaining amount of fuel in the fuel tank based on the above, when the detection condition that the absolute value of the acceleration of the vehicle is smaller than a predetermined value is satisfied while the vehicle is running, The gist is to permit detection of the remaining amount of fuel based on the output signal and prohibit detection of the remaining amount of fuel based on the output signal when the detection condition is not satisfied.

  According to the above configuration, even when the vehicle has a risk of large fluctuations in the fuel level in the fuel tank, the absolute value of the acceleration of the vehicle is small. When there is a high possibility that the fluctuation is small, detection of the remaining amount of fuel based on the output signal of the level sensor is permitted, so that an opportunity to detect the remaining amount of fuel can be secured. In addition, when the absolute value of the acceleration of the vehicle is large, in other words, when there is a high possibility that the fuel level is greatly fluctuated, detection of the remaining amount of fuel based on the output signal of the level sensor is prohibited. A decrease in the remaining amount detection accuracy can be suppressed. As described above, according to the above-described configuration, it is possible to secure a chance to detect the remaining amount of fuel while suppressing a decrease in the detection accuracy of the remaining amount of fuel, and to appropriately detect the remaining amount of fuel.

  The invention according to claim 2 is applied to a vehicle provided with a fuel tank for storing fuel, and includes a level sensor for detecting a liquid level of the fuel in the fuel tank, and an output signal of the level sensor In the fuel remaining amount detecting device for detecting the fuel remaining amount in the fuel tank based on the vehicle, the absolute value of the acceleration of the vehicle is smaller than a predetermined value while the vehicle is traveling, and the steering angle of the vehicle is predetermined. The gist is to allow detection of the remaining amount of fuel based on the output signal when the detection condition that the angle is smaller is satisfied, and prohibit detection of the remaining amount of fuel based on the output signal when the detection condition is not satisfied. .

  According to the above configuration, even when the vehicle has a risk of large fluctuations in the fuel liquid level in the fuel tank, when the absolute value of the acceleration of the vehicle is small and the steering angle of the vehicle is small, In other words, when there is a high possibility that the fluctuation of the fuel level is small, detection of the remaining amount of fuel based on the output signal of the level sensor is permitted. it can. In addition, when the absolute value of the vehicle acceleration is large or when the vehicle steering angle is large, in other words, when there is a high possibility that the fuel level fluctuation is large, the remaining amount of fuel based on the output signal of the level sensor Since detection is prohibited, it is possible to suppress a decrease in detection accuracy of the remaining amount of fuel. As described above, according to the above-described configuration, it is possible to secure a chance to detect the remaining amount of fuel while suppressing a decrease in the detection accuracy of the remaining amount of fuel, and to appropriately detect the remaining amount of fuel.

  The invention according to claim 3 is applied to a vehicle provided with a fuel tank for storing fuel, and includes a level sensor for detecting a liquid level of the fuel in the fuel tank, and an output signal of the level sensor. In the fuel remaining amount detecting device for detecting the remaining amount of fuel in the fuel tank based on the condition, the output signal when the detection condition that the steering angle of the vehicle is smaller than a predetermined angle is satisfied while the vehicle is traveling The gist of the invention is to permit the detection of the remaining amount of fuel based on the fuel consumption and prohibit the detection of the remaining fuel amount based on the output signal when the detection condition is not satisfied.

  According to the above configuration, even when the vehicle has a risk of large fluctuations in the fuel level in the fuel tank, if the steering angle of the vehicle is small, in other words, fluctuations in the fuel level. When there is a high possibility that the situation is small, detection of the remaining amount of fuel based on the output signal of the level sensor is permitted, so that an opportunity to detect the remaining amount of fuel can be secured. In addition, when the steering angle of the vehicle is large, in other words, when there is a high possibility that the fuel level is greatly fluctuated, detection of the remaining amount of fuel based on the output signal of the level sensor is prohibited, so that the remaining fuel amount The reduction in detection accuracy can be suppressed. As described above, according to the above-described configuration, it is possible to secure a chance to detect the remaining amount of fuel while suppressing a decrease in the detection accuracy of the remaining amount of fuel, and to appropriately detect the remaining amount of fuel.

  According to a fourth aspect of the present invention, in the fuel remaining amount detecting device according to the first or second aspect, the detection condition is provided on the condition that the state where the absolute value of the acceleration is smaller than a predetermined value is continued for a predetermined period. The gist of this is to determine that is true.

According to a fifth aspect of the present invention, in the fuel remaining amount detecting device according to the second or third aspect,
The gist is to determine that the detection condition is satisfied on the condition that the state where the steering angle is smaller than the predetermined angle is continued for a predetermined period.

  According to the configuration of claim 4 or 5, the remaining amount of fuel is detected only under a condition where the possibility that the fluctuation of the fuel level is likely to be reduced due to the continuation of the state where the possibility of the fluctuation of the fuel liquid level is high is high. And the remaining amount of fuel can be detected with high accuracy.

  According to a sixth aspect of the present invention, in the fuel remaining amount detecting device according to any one of the first to fifth aspects, the vehicle is an internal combustion engine that can use gasoline and alcohol as the fuel. And the fuel tank stores fuel for supplying to the internal combustion engine.

  In recent years, internal combustion engines that can use alcohol and gasoline as fuel are being put into practical use. This internal combustion engine can be operated using only alcohol or only gasoline as fuel, and can also be operated using a mixed fuel in which alcohol and gasoline are mixed at an arbitrary ratio. Since the properties of the fuel change with the change in the alcohol concentration of the fuel, the amount of fuel that can be burned in a stable state varies depending on the alcohol concentration. For this reason, in an internal combustion engine in which the above mixed fuel is used, it is required to execute control (so-called fuel injection control) for adjusting the fuel supply amount in a manner corresponding to the alcohol concentration of the fuel.

  According to the above configuration, the remaining amount of fuel in the fuel tank in which the fuel to be supplied to the internal combustion engine is stored can be detected with a relatively high frequency. Therefore, when fuel is replenished into the fuel tank, this can be determined early with an increase in the remaining amount of fuel. At this time, assuming that the alcohol concentration of the fuel may change, the fuel injection control can be executed in a manner corresponding to such a situation.

  According to a seventh aspect of the present invention, in the fuel remaining amount detecting device according to the sixth aspect, the vehicle calculates an increase degree of fuel in the fuel tank based on the detected remaining fuel amount and The gist thereof is that the operation control of the internal combustion engine is executed based on the calculated degree of increase.

  According to the above configuration, the degree of increase in the fuel in the fuel tank is used as a value for determining whether the fuel has been replenished, a change range in which the alcohol concentration of the fuel may change with the replenishment, and the like. be able to. Therefore, the engine control can be appropriately executed immediately after the fuel tank is refueled.

  The degree of increase includes the amount of increase in the remaining amount of fuel and the rate of increase in the amount of remaining fuel.

Hereinafter, an embodiment in which a fuel remaining amount detection apparatus according to the present invention is embodied will be described.
FIG. 1 shows an overall configuration of a vehicle provided with a fuel remaining amount detection device according to the present embodiment.
As shown in FIG. 1, the vehicle 10 is equipped with an internal combustion engine 11 as a power source. The internal combustion engine 11 can use two types of fuel, gasoline and alcohol, and can be operated using only alcohol or only gasoline as fuel. Operation using a mixed fuel mixed in proportion is also possible. The vehicle 10 is provided with a fuel tank 12 storing fuel to be supplied to the internal combustion engine 11 and an injector 13 for supplying the fuel in the fuel tank 12 to the combustion chamber 15 of the internal combustion engine 11.

  The vehicle 10 is provided with an electronic control unit 20. The electronic control unit 20 temporarily stores a CPU that performs arithmetic processing for various controls related to the operation of the internal combustion engine 11, a non-volatile memory (ROM) in which a control program and data are stored, a CPU calculation result, and the like. A volatile memory (RAM), a nonvolatile memory (EEPROM), and an input / output port for inputting / outputting signals to / from the outside.

  The vehicle 10 is provided with various sensors for detecting the driving state. Examples of such sensors include a rotational speed sensor 21 for detecting the rotational speed of the output shaft 14 of the internal combustion engine 11 (engine rotational speed NE), and the amount of air sucked into the combustion chamber 15 of the internal combustion engine 11 (suction). An air flow meter 22 for detecting the air amount GA) is provided. Further, the accelerator sensor 23 for detecting the depression amount of the accelerator pedal 16 (accelerator depression amount ACC), the steering angle sensor 24 for detecting the steering angle of the steering wheel 17, and the traveling speed (vehicle speed SPD) of the vehicle 10 are detected. A speed sensor 25 for detecting the air-fuel ratio and an air-fuel ratio sensor 26 for detecting the air-fuel ratio of the air-fuel mixture through the oxygen concentration of the exhaust gas are provided. In addition, an operation switch 27 operated by the driver to switch between operation and stop of the internal combustion engine 11 and a level sensor 28 for detecting the amount of fuel stored in the fuel tank 12 (fuel remaining amount). Etc. are also provided. The level sensor 28 is a type having a float that floats on the liquid level in the fuel in the fuel tank 12 and that detects the liquid level (liquid level) of the fuel. .

  Output signals from these sensors are input to the electronic control unit 20. The electronic control unit 20 performs various calculations based on the output signals of these sensors, and controls various operations related to the operation of the internal combustion engine 11 such as drive control (fuel injection control) of the injector 13 based on the calculation results. Execute.

  Here, when a fuel having an alcohol concentration different from that of the fuel stored in the fuel tank 12 is replenished, the alcohol concentration of the fuel in the fuel tank 12 changes, and the properties of the fuel change accordingly. . Therefore, the amount of fuel that can be burned in a stable state in the internal combustion engine 11 will be different depending on the alcohol concentration. In view of this point, in the present embodiment, the fuel injection control is executed in accordance with the alcohol concentration of the fuel stored in the fuel tank 12.

Hereinafter, an execution mode of such fuel injection control will be specifically described.
During operation of the internal combustion engine 11, basically, adjustment of the fuel injection amount in the fuel injection control is executed as follows.

  That is, first, the basic injection amount Tb and the feedback correction amount Kfb are calculated, and the air-fuel ratio learning value Gaf and the alcohol concentration learning value Gal are read. Then, a control target value (required injection amount Tq) for the fuel injection amount is obtained based on these values Tb, Kfb, Gaf, Gal, and the injector 13 is injected so that the same amount of fuel as this required injection amount Tq is injected. Is opened.

  The “basic injection amount Tb” is a basic value for the fuel injection amount, and is calculated from a map based on the intake air amount GA and the engine rotational speed NE. In this map, the fuel injection amount (basic injection amount Tb) that can bring the air-fuel ratio of the operating state determined by the intake air amount GA and the engine rotational speed NE and the air-fuel ratio of the air-fuel mixture into a desired ratio (for example, the theoretical air-fuel ratio). ) Is determined and set in advance based on experimental results. Further, the intake air amount GA is adjusted through a separate process in accordance with the accelerator depression amount ACC and the engine speed NE.

  The “feedback correction amount Kfb” is a correction term that is calculated when the air-fuel ratio feedback process is executed, so that the actual air-fuel ratio of the air-fuel mixture and the desired air-fuel ratio (for example, the stoichiometric air-fuel ratio) match. This is a value calculated based on the difference between the output signal of the air-fuel ratio sensor 26 and its reference value. The air-fuel ratio feedback process is not executed when the internal combustion engine 11 is started or when the temperature of the internal combustion engine 11 is low. Therefore, when the air-fuel ratio feedback process is not executed, the feedback correction amount Kfb is not calculated, and the required injection amount Tq is obtained based on the basic injection amount Tb, the air-fuel ratio learning value Gaf, and the alcohol concentration learning value Gal.

  Further, the “air-fuel ratio learning value Gaf” is a learning term calculated when the air-fuel ratio feedback process is executed, and the individual difference of components (injector 13 and the like) of the fuel supply system that supplies fuel to the internal combustion engine 11 Or a value for compensating for a steady deviation between the actual air-fuel ratio of the air-fuel mixture and the desired air-fuel ratio due to changes over time. The air-fuel ratio learning value Gaf is changed to a value smaller by a predetermined value when the output signal of the air-fuel ratio sensor 26 is rich (actual air-fuel ratio <desired air-fuel ratio), while the output signal is lean. When the value indicates (actual air / fuel ratio> desired air / fuel ratio), the value is changed based on the output signal of the air / fuel ratio sensor 26 so that the value is increased by a predetermined value. The air / fuel ratio learning value Gaf is stored in a non-volatile memory of the electronic control unit 20.

  The “alcohol concentration learning value Gal” is a learning term that is calculated when the air-fuel ratio feedback process is executed. The actual air-fuel ratio of the air-fuel mixture resulting from the change in the alcohol concentration of the fuel, the desired air-fuel ratio, This is a value for compensating for the deviation. The alcohol concentration learning value Gal is changed in the same manner as the air-fuel ratio learning value Gaf. However, in the process of learning the alcohol concentration learning value Gal, the air-fuel ratio learning value Gaf is set at the timing when the execution of the air-fuel ratio feedback process is started on the condition that the fuel supply into the fuel tank 12 is performed. It is executed after prohibiting execution of the learning process. This alcohol concentration learning value Gal is also stored in the non-volatile memory of the electronic control unit 20 as with the air-fuel ratio learning value Gaf.

On the other hand, when the internal combustion engine 11 is started, adjustment of the fuel injection amount in the fuel injection control is executed as follows.
That is, in this case, the basic injection amount Qst and the replenishment correction amount Ks are calculated, and the alcohol concentration learning value Gal is read. Then, a control target value (required injection amount Tqst) for the fuel injection amount is obtained based on these values Qst, Ks, Gal, and the injector 13 is driven to open so that the same amount of fuel as this required injection amount Tqst is injected. Is done.

  The “basic injection amount Qst” is a value calculated from a map based on the temperature of the internal combustion engine 11 (specifically, the temperature of engine cooling water). The map shows the relationship between the value (basic injection amount Qst) corresponding to the fuel injection amount that can reliably start the internal combustion engine 11 when the alcohol concentration is a predetermined concentration and the temperature of the internal combustion engine 11. Is determined and set in advance based on experimental results.

  The “replenishment correction amount Ks” is a value calculated based on a fuel replenishment ratio Rvf described later. As the fuel supply ratio Rvf, a value corresponding to a value obtained by dividing the remaining fuel amount before refueling by the remaining fuel amount after refueling is calculated. Here, when the fuel is supplied into the fuel tank 12, the alcohol concentration of the fuel in the fuel tank 12 changes, and the alcohol concentration learning value learned through the above-described processing and stored in the electronic control unit 20 is stored. In some cases, Gal and the learning value corresponding to the alcohol concentration of the actual fuel are largely separated from each other. In this case, not only the combustion state of the fuel is deteriorated, but also misfire may occur. In such a situation when the internal combustion engine 11 is started, the startability is deteriorated due to the deterioration of the combustion state. In view of this point, as the replenishment correction amount Ks, the starting performance of the internal combustion engine 11 is ensured even when the alcohol concentration of the fuel in the fuel tank 12 greatly changes with fuel replenishment. A value is calculated. In the present embodiment, it is determined that the fuel has been replenished by determining that the fuel replenishment ratio Rvf is greater than a predetermined value.

  By the way, in order to properly execute the fuel injection control when the alcohol concentration of the fuel in the fuel tank 12 changes as the fuel is replenished, it is desirable to determine at an early stage that the fuel has been replenished. It is desirable that the fuel supply ratio Rvf be calculated early.

  However, as described above, while the vehicle 10 is traveling, the fuel level in the fuel tank 12 fluctuates due to acceleration / deceleration or turning of the vehicle 10 or a change in the inclination angle of the traveling road surface. The detection accuracy of the remaining amount tends to be lowered. On the other hand, if the detection of the remaining amount of fuel is prohibited while the vehicle 10 is traveling as described above, the period during which the remaining amount of fuel can be detected becomes very short, and the remaining amount of fuel at that time may be reduced. The amount cannot be monitored properly.

  In view of such circumstances, in the present embodiment, detection of the remaining amount of fuel is permitted only in the following situations. That is, first, when the vehicle 10 is stopped, detection of the remaining amount of fuel based on the output signal Vf is permitted when the fluctuation range of the output signal Vf of the level sensor 28 is small. Further, while the vehicle 10 is traveling, in addition to the condition that “the fluctuation range of the output signal Vf of the level sensor 28 is small”, the condition that “the absolute value of the acceleration of the vehicle 10 is small”, and “ Detection of the remaining amount of fuel based on the output signal Vf of the level sensor 28 is permitted when the condition that the steering angle of the vehicle 10 is small is satisfied.

  Thus, when the vehicle 10 is stopped and the fuel level in the fuel tank 12 is not shaking, or when the fuel level fluctuation is small after the vehicle 10 is stopped, the remaining fuel level is detected. It is executed immediately and the remaining amount of fuel is accurately detected. Further, even when the vehicle 10 is stopped, if the fuel level in the fuel tank 12 is not shaken immediately after the vehicle 10 is stopped, detection of the remaining amount of fuel is prohibited, and the detection accuracy decreases. It will be suppressed.

  On the other hand, even when the vehicle 10 is traveling, there is a high possibility that the fluctuation of the fuel level in the fuel tank 12 is small (specifically, the change in the traveling speed of the vehicle 10 is small). When the turning radius of the vehicle 10 is large and the fluctuation range of the output signal Vf of the level sensor 28 is small), detection of the remaining amount of fuel is permitted. Therefore, when the vehicle 10 is traveling, the remaining amount of fuel can be detected at an early stage as compared with the case where detection of the remaining amount of fuel in the fuel tank 12 is necessarily prohibited. Further, when the vehicle 10 is traveling, there is a high possibility that the fuel level in the fuel tank 12 is greatly fluctuated (specifically, the traveling speed of the vehicle 10 is large or the vehicle 10 is turning) When the radius is small or the fluctuation range of the output signal Vf of the level sensor 28 is large), detection of the remaining amount of fuel is prohibited. As a result, the detection of the remaining amount of fuel is permitted only when the fuel level is expected to be small while the vehicle 10 is traveling, and the remaining amount of fuel is detected while the vehicle 10 is traveling. Even if it is performed, a decrease in the detection accuracy can be accurately suppressed.

  As described above, in the present embodiment, the detection of the remaining amount of fuel in the fuel tank 12 can be performed early and accurately, and as a result, it is possible to determine whether the fuel tank 12 has been refueled. Similarly, the calculation of the fuel supply ratio Rvf is performed early and accurately. Therefore, when the fuel is refilled into the fuel tank 12, the transition of the execution mode of the fuel injection control at the start of the internal combustion engine 11 to the execution mode suitable for the fuel supply or the learning of the alcohol concentration learning value Gal is performed. The shift to the processing to be performed is completed at an early stage, and the shift to the engine control is performed promptly in view of the change in the fuel property due to the refueling.

Hereinafter, the details of the process for detecting the remaining fuel amount (fuel remaining amount detection process) will be described.
FIG. 2 is a flowchart showing an execution procedure of the remaining fuel amount detection process, and a series of processes shown in the flowchart is executed by the electronic control unit 20 as a process for each predetermined cycle.

  As shown in FIG. 2, in this process, it is first determined whether or not the vehicle 10 is stopped (step S10). Here, it is determined that the vehicle 10 is stopped when the vehicle speed SPD is equal to or lower than a predetermined speed (for example, 1.0 km per hour). And when it is judged that the vehicle 10 has stopped (step S10: YES), the process at the time of stop (step S11) is performed.

FIG. 3 shows a specific execution procedure of this stop process.
As shown in FIG. 3, in the stop process, first, a gradual change value Vfsm for the output signal Vf of the level sensor 28 is calculated (step S110). The gradual change value Vfsm is a value that is reset to the initial value when the operation switch 27 is turned off. When the operation switch 27 is turned on, the output signal Vf of the level sensor 28 at that time is stored as the gradual change value Vfsm. Thereafter, when the previously calculated gradual change value is “Vfsmi” and the predetermined coefficient is “n (positive number)”, the gradual change value Vfsm is calculated through the following relational expression (1).

Vfsm ← Vfsmi + (Vf−Vfsmi) / n (1)

After the gradual change value Vfsm is calculated as described above, it is determined whether or not the count value Csp of the stop-time stable counter is “0” (step S111). This stop-time stable counter is a counter whose count value Csp is reset to “0” when the operation switch 27 is turned off. When the count value Csp of the stable counter for stop is “0” (step S111: YES), the output signal Vf of the level sensor 28 at this time is stored as the reference value Vfb1 (step S112). The reference value Vfb1 is a value that is reset to an initial value when the operation switch 27 is turned off. On the other hand, when the count value Csp of the stop-time stable counter is not “0” (step S111: NO), the process of step S112 is jumped.

  Next, an absolute value (| Vfb1-Vf |) of a difference between the reference value Vfb1 and the output signal Vf is obtained, and it is determined whether or not the absolute value is smaller than a predetermined value Tsp (step S113). As the predetermined value Tsp, a value that can accurately determine that the fluctuation of the fuel level in the fuel tank 12 is small is obtained in advance based on experimental results and stored.

  If the absolute value is smaller than the predetermined value Tsp (step S113: YES), it is highly possible that the fluctuation of the fuel level in the fuel tank 12 is small at this time. The value Csp is incremented (step S114). On the other hand, if the absolute value is equal to or greater than the predetermined value Tsp (step S113: NO), it is highly likely that the fuel liquid level in the fuel tank 12 is greatly shaken at this time. The count value Csp is reset to “0” (step S115).

  Thereafter, it is determined whether or not the count value Csp of the stop counter is greater than a predetermined value Asp (step S116). The predetermined value Asp is a value that can be used to determine that the situation where the fluctuation of the fuel liquid level is small is continued for a sufficient period of time so that the gradual change value Vfsm becomes a value corresponding to the actual liquid level. Is obtained and stored in advance based on experimental results and the like.

  When the count value Csp is larger than the predetermined value Asp (step S116: YES), a state that the possibility that the fluctuation of the fuel level is small is continued for a predetermined period, and the gradually changing value Assuming that Vfsm is a value corresponding to the actual liquid level, the gradual change value Vfsm is stored as a temporary value Vfspn (step S117). The temporary value Vfspn is a non-volatile value of the electronic control unit 20 as a value corresponding to the remaining amount of fuel when the operation of the internal combustion engine 11 is stopped when the operation switch 27 is turned off (the remaining fuel amount Vfsp when stopped). A value stored in memory.

  On the other hand, when the count value Csp of the stop counter is equal to or less than the predetermined value Asp (step S116: NO), the operation switch 27 is turned on from the stop fuel remaining amount Vfsp stored in the electronic control unit 20. After that, the value obtained by subtracting the integrated value of the fuel injection amount is stored as a temporary value Vfspn (step S118). That is, in this case, since the continuation of the state in which there is a high possibility that the fluctuation of the fuel liquid level is large or that the fluctuation is small is not reached the predetermined period, Assuming that the value Vfsm is not a value that matches the actual liquid level, a value with higher accuracy than the gradual change value Vfsm (the fuel remaining amount obtained from the integrated value of the fuel injection amount and the remaining fuel amount Vfsp at the time of stoppage) ) Is stored as the provisional value Vfspn. The integrated value of the fuel injection amount is calculated based on the required injection amount at that time through a separate process.

  After such stop process (step S11 in FIG. 2), it is determined whether or not the execution flag is turned off (step S12). The execution flag is a flag that is turned on when the fuel supply ratio Rvf is calculated, and is turned off when the operation switch 27 is turned off. It can be seen that there is no history in which the fuel supply ratio Rvf has been calculated after the operation switch 27 is turned on because the execution flag is turned off.

  If the execution flag is turned off (step S12: YES), the gradual change value Vfsm at this time and the remaining fuel amount Vfsp at the stop stored in the nonvolatile memory of the electronic control unit 20 are used. Based on the following relational expression (2), the fuel supply ratio Rvf is calculated (step S13), and the execution flag is turned on (step S14).

Rvf = Vfsm / Vfsp (2)

When the execution flag is turned on (step S12: NO), the fuel supply ratio Rvf is not calculated, and the execution flag is not turned on (the process of step S13 and the process of step S14 are jumped). . The fuel supply ratio Rvf is a value that is reset to an initial value (for example, “1.0”) when the operation switch 27 is turned off.

  Thereafter, on condition that the operation switch 27 is turned off (step S15: YES), the temporary value Vfspn is stored as the remaining fuel amount Vfsp at the time of stop (step S16), and then this process is temporarily ended.

  On the other hand, if it is determined in step S10 that the vehicle 10 is traveling (step S10: NO), it is determined whether or not the execution flag is turned off (step S17). When the execution flag is turned off (step S17: YES), the fuel supply ratio Rvf is calculated through the next process (steps S18 to S20). That is, first, a running process (step S18) is executed.

FIG. 4 shows an execution procedure of the running process.
As shown in FIG. 4, in the running process, it is first determined whether or not the count value Crn of the running stability counter is “0” (step S180). This running stability counter is a counter whose count value Crn is reset to “0” when the operation switch 27 is turned off. If the count value Crn of the running stability counter is “0” (step S180: YES), the output signal Vf of the level sensor 28 at this time is stored as the reference value Vfb2 (step S181). The reference value Vfb2 is a value that is reset to an initial value when the operation switch 27 is turned off. On the other hand, when the count value Crn of the running stability counter is not “0” (step S180: NO), the process of step S181 is jumped.

Next, it is determined whether or not an execution condition is satisfied (step S182). Here, it is determined that the execution condition is satisfied when all of the following (Condition A) to (Condition C) are satisfied.
(Condition A) The absolute value (| Vfb2-Vf |) of the difference between the reference value Vfb2 and the output signal Vf is smaller than the predetermined value Trn. As the predetermined value Trn, a value capable of accurately determining that the fluctuation of the fuel level in the fuel tank 12 is small is obtained in advance based on experimental results and stored. .
(Condition b) The absolute value of the acceleration of the vehicle 10 is smaller than the predetermined value B. Specifically, the amount of change per unit time (for example, several tens of milliseconds) of the vehicle speed SPD is smaller than the predetermined value B. As the predetermined value B, it is accurately determined that the degree of fluctuation of the fuel liquid level in the fuel tank 12 is suppressed to such an extent that the influence on the detection of the liquid level through the level sensor 28 is very small. Are obtained in advance based on experimental results and stored.
(Condition C) The steering angle of the vehicle 10 is smaller than the predetermined angle C. Specifically, the steering angle of the steering wheel 17 is smaller than the predetermined angle C. The predetermined angle C is determined with high accuracy that the degree of fluctuation of the fuel liquid level in the fuel tank 12 can be suppressed to such an extent that the influence on the detection of the liquid level through the level sensor 28 is very small. Are obtained in advance based on experimental results and stored.

  When the execution condition is satisfied (step S182: YES), although the vehicle 10 is traveling, the variation in the traveling speed is small, the turning radius is large, and the fluctuation range of the output signal Vf of the level sensor 28 Therefore, there is a high possibility that the fuel level in the fuel tank 12 is small due to acceleration / deceleration and turning of the vehicle 10 and turning, and a change in the inclination angle of the traveling road surface, and the fluctuation of the fuel liquid level is small. To be judged. At this time, the count value Crn of the running stability counter is incremented (step S183). On the other hand, when the execution condition is not satisfied (step S182: NO), the movement of the fuel in the fuel tank 12 due to acceleration / deceleration and turning of the vehicle 10 and the change in the inclination angle of the traveling road surface is large, and the fuel tank 12 Therefore, the count value Crn of the traveling stability counter is reset to “0” (step S184).

  After such travel processing (step S18 in FIG. 2), it is determined whether the count value Crn of the travel stability counter is greater than a predetermined value Arn (step S19). In addition, as the predetermined value Arn, the situation where the fluctuation of the fuel liquid level is small for a period sufficient for the output signal Vf of the level sensor 28 to be a value close to a value corresponding to the actual liquid level is continued. A value capable of determining this is obtained and stored in advance based on the experimental result or the like.

  When the count value Crn is greater than the predetermined value Arn (step S19: YES), a state where the possibility that the fluctuation of the fuel liquid level is small during the traveling of the vehicle 10 is high is continued for a predetermined period. Assuming that the output signal Vf of the level sensor 28 is close to a value corresponding to the actual liquid level, the detection of the output signal Vf of the level sensor 28, and the fuel supply ratio Rvf based on the output signal Vf It is determined that the condition (detection condition) for executing the calculation is established. At this time, the fuel replenishment ratio Rvf is obtained from the following relational expression (3) based on the output signal Vf of the level sensor 28 and the remaining fuel amount Vfsp at the time of stop stored in the nonvolatile memory of the electronic control unit 20. Calculated (step S20).

Rvf = Vf / Vfsp (3)

After the fuel supply ratio Rvf is calculated in this way, the execution flag is turned on (step S14).

  When the count value Crn is equal to or less than the predetermined value Arn (step S19: NO), the fuel supply ratio Rvf is not calculated, and the execution flag is not turned on (the process of step S20 and the process of step S14 are jumped). ) If the execution flag is turned on (step S17: NO), the processes of steps 18 to S20 and S14 are jumped.

  Thereafter, on condition that the operation switch 27 is turned off (step S15: YES), the temporary value Vfspn is stored as the remaining fuel amount Vfsp at the time of stop (step S16), and then this process is temporarily ended.

  In the present embodiment, the remaining fuel amount in the fuel tank 12 can be detected at a relatively high frequency by executing such a remaining fuel amount detection process. Therefore, when fuel is refilled into the fuel tank 12, it can be determined at an early stage by increasing the remaining amount of fuel. At this time, the alcohol concentration of the fuel may change. , It will be possible to execute the engine control according to the situation.

As described above, according to the present embodiment, the effects described below can be obtained.
(1) While the vehicle 10 is traveling, when the detection condition including (Condition B) and (Condition C) is satisfied, the detection of the remaining amount of fuel based on the output signal Vf of the level sensor 28 is permitted, and the detection condition is not satisfied. Sometimes the detection of the remaining amount of fuel based on the output signal Vf is prohibited. As a result, even when the vehicle 10 is traveling, where the fuel level in the fuel tank 12 may be greatly shaken, the absolute value of the acceleration of the vehicle 10 is small and the steering angle of the vehicle 10 is small. In other words, when there is a high possibility that the fluctuation of the fuel liquid level is small, detection of the remaining amount of fuel based on the output signal Vf of the level sensor 28 is permitted. Therefore, an opportunity to detect the remaining amount of fuel can be ensured. Moreover, when the absolute value of the acceleration of the vehicle 10 is large or when the steering angle of the vehicle 10 is large, in other words, when there is a high possibility that the fuel liquid level is greatly shaken, it is based on the output signal Vf of the level sensor 28. Since detection of the remaining amount of fuel is prohibited, it is possible to suppress a decrease in detection accuracy of the remaining amount of fuel. Accordingly, it is possible to secure an opportunity to detect the remaining amount of fuel while suppressing a decrease in the detection accuracy of the remaining amount of fuel, and to appropriately detect the remaining amount of fuel.

  (2) It is determined that the detection condition is satisfied on the condition that the execution condition consisting of (Condition A) to (Condition C) is satisfied for a predetermined period. Therefore, it is possible to detect the remaining amount of fuel under conditions where there is a high possibility that the fluctuation of the fuel level will be small and the fluctuation is very small. Can be detected.

  (3) In a vehicle 10 equipped with an internal combustion engine 11 that can use gasoline and alcohol as fuel, the remaining amount of fuel in a fuel tank 12 stocked with fuel to be supplied to the internal combustion engine 11 is compared. It is possible to detect with high detection frequency. Therefore, when fuel is refilled into the fuel tank 12, it can be determined at an early stage by increasing the remaining amount of fuel. At this time, the alcohol concentration of the fuel may change. , It will be possible to execute the engine control according to the situation.

  (4) The remaining amount of fuel is detected based on the output signal Vf of the level sensor 28, and the increase degree of fuel in the fuel tank 12 (fuel supply ratio Rvf) is accurately calculated based on the detected remaining fuel amount. be able to. The fuel replenishment ratio Rvf can be used as a value for determining whether the fuel has been replenished, a change range in which the alcohol concentration of the fuel may change with the replenishment, and the like. Immediately after the fuel supply to the inside is performed, the engine control can be appropriately executed.

The embodiment described above may be modified as follows.
An acceleration sensor for detecting the acceleration of the vehicle 10 is newly provided, and it is determined that (condition b) is satisfied when the absolute value of the acceleration of the vehicle 10 detected through the acceleration sensor is smaller than a predetermined value. May be. Further, the acceleration of the vehicle 10 is estimated based on the driving state of the vehicle 10 such as the accelerator depression amount ACC, the intake air amount GA, the engine rotation speed NE, and the absolute value of the estimated acceleration is smaller than a predetermined value. It may be determined that (Condition B) is satisfied. In short, if it is possible to appropriately determine that the condition “the absolute value of acceleration of the vehicle 10 is smaller than the predetermined value B” is satisfied, the acceleration detection method or estimation method is arbitrarily changed. be able to.

  -A steering angle sensor for detecting the steering angle of the steering wheel of the vehicle 10 is newly provided, and it is determined that (Condition C) is satisfied when the steering angle detected through the sensor is larger than a predetermined angle. Also good. Further, if the vehicle is equipped with a navigation system, the steering angle of the vehicle 10 is estimated from the map information of the system, and it is determined that (Condition C) is satisfied when the estimated steering angle is smaller than a predetermined angle. May be. In short, as long as it can be properly determined that the condition that “the steering angle of the vehicle 10 is smaller than the predetermined angle C” can be satisfied, the method for detecting or estimating the steering angle of the vehicle 10 is arbitrary. It can be changed.

Any one of (Condition B) and (Condition C) in the execution condition may be omitted. It is also possible to omit (condition a) in the execution condition.
-You may abbreviate | omit the process of step S118 of FIG.

  When the vehicle 10 is traveling, the gradual change value Vfsm for the output signal Vf of the level sensor 28 may be calculated and used for calculating the fuel supply ratio Rvf, as in the case where the vehicle 10 is stopped.

  The process of calculating the gradual change value Vfsm for the output signal Vf of the level sensor 28 when the vehicle 10 is stopped (step S110 in FIG. 3) may be omitted. In such a configuration, instead of calculating the fuel supply ratio Rvf from the relational expression (2) based on the gradual change value Vfsm, the fuel from the relational expression (3) using the output signal Vf of the level sensor 28 is used. The replenishment ratio Rvf may be calculated.

  Instead of the fuel supply ratio Rvf, a fuel supply amount (for example, “gradual change value Vfsm−stopped fuel remaining amount Vfsp” or “output signal Vf−stopped fuel remaining amount Vfsp”) may be detected. In short, any value other than the fuel supply ratio Rvf, such as an increase rate of the remaining amount of fuel or an increase amount of the remaining amount of fuel, is calculated as long as the value corresponds to the degree of increase in the amount of fuel at the time of fuel supply to the fuel tank 12. You may make it do.

  The present invention is not limited to a vehicle that uses the detected remaining fuel level for determining whether fuel has been replenished or calculating the degree of increase in fuel, but for vehicles that are used for purposes other than the above, such as displaying the remaining fuel level. It can also be applied to.

  The present invention can also be applied to a vehicle equipped with an internal combustion engine in which only gasoline is used as fuel.

1 is a schematic diagram showing a schematic configuration of a vehicle to which an embodiment embodying a fuel remaining amount detection device according to the present invention is applied. The flowchart which shows the execution procedure of fuel remaining amount detection processing. The flowchart which shows the execution procedure of the process at the time of a stop. The flowchart which shows the execution procedure of the process at the time of driving | running | working.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 10 ... Vehicle, 11 ... Internal combustion engine, 12 ... Fuel tank, 13 ... Injector, 14 ... Output shaft, 15 ... Combustion chamber, 16 ... Accelerator pedal, 17 ... Steering, 20 ... Electronic control unit, 21 ... Rotation speed sensor, 22 DESCRIPTION OF SYMBOLS ... Air flow meter, 23 ... Accelerator sensor, 24 ... Steering angle sensor, 25 ... Speed sensor, 26 ... Air-fuel ratio sensor, 27 ... Operation switch, 28 ... Level sensor.

Claims (7)

A level sensor that is applied to a vehicle provided with a fuel tank for storing fuel and detects a liquid level of the fuel in the fuel tank, and the fuel in the fuel tank based on an output signal of the level sensor In the fuel remaining amount detecting device for detecting the remaining amount,
The detection of the remaining amount of fuel based on the output signal is permitted when the detection condition that the absolute value of acceleration of the vehicle is smaller than a predetermined value is satisfied while the vehicle is traveling, and the output is output when the detection condition is not satisfied. A fuel remaining amount detection device, which prohibits detection of a remaining amount of fuel based on a signal. A level sensor that is applied to a vehicle provided with a fuel tank for storing fuel and detects a liquid level of the fuel in the fuel tank, and the fuel in the fuel tank based on an output signal of the level sensor In the fuel remaining amount detecting device for detecting the remaining amount,
When the detection condition that the absolute value of acceleration of the vehicle is smaller than a predetermined value and the steering angle of the vehicle is smaller than a predetermined angle is satisfied while the vehicle is running, the remaining amount of fuel is detected based on the output signal. A fuel remaining amount detection device that permits and detects the remaining amount of fuel based on the output signal when the detection condition is not satisfied. A level sensor that is applied to a vehicle provided with a fuel tank for storing fuel and detects a liquid level of the fuel in the fuel tank, and the fuel in the fuel tank based on an output signal of the level sensor In the fuel remaining amount detecting device for detecting the remaining amount,
The detection of the remaining amount of fuel based on the output signal is permitted when the detection condition that the vehicle is traveling and the steering angle of the vehicle is smaller than a predetermined angle is satisfied, and the output signal is detected when the detection condition is not satisfied. A fuel remaining amount detecting device that prohibits detection of the remaining amount of fuel based on the fuel cell. The fuel remaining amount detecting device according to claim 1 or 2,
It is determined that the detection condition is satisfied on the condition that the state where the absolute value of the acceleration is smaller than a predetermined value is continued for a predetermined period. The fuel remaining amount detecting device according to claim 2 or 3,
It is determined that the detection condition is satisfied on the condition that the state where the steering angle is smaller than the predetermined angle is continued for a predetermined period. In the fuel residual amount detection apparatus as described in any one of Claims 1-5,
The vehicle is equipped with an internal combustion engine that can use gasoline and alcohol as the fuel as a power source,
The fuel tank is for storing fuel to be supplied to the internal combustion engine. The fuel remaining amount detecting device according to claim 6,
In the vehicle, the degree of increase in the fuel in the fuel tank is calculated based on the detected remaining fuel amount, and the operation control of the internal combustion engine is executed based on the calculated degree of increase. A fuel remaining amount detecting device characterized by the above.

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