JP2007008386A - Fuel remaining amount calculating device for vehicle - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To promptly detect changes of fuel remaining amount after refueling during stopping of an engine, and to detect actual fuel remaining amount from restarting of the engine as an initial value. <P>SOLUTION: If a refueling cap is closed during the stopping of the engine, the fuel remaining amount calculating device stands by in a low power consumption mode. On the other hand, if the refueling cap is opened during the stopping of the engine, the device is returned from the low power consumption mode to a normal mode, and operates a fuel level gage to calculate the fuel remaining amount. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a fuel remaining amount calculation device for a vehicle that calculates a remaining fuel amount based on a detection signal from a fuel level gauge that detects a fuel level in a fuel tank.

Patent Document 1 stores a measurement result of a level gauge in a state where the fuel level is stable, and subtracts a time integral value of the fuel consumption from the recent stored value, thereby obtaining an instantaneous value of the remaining amount of fuel. A method for detecting the required remaining fuel amount is disclosed.
Japanese Patent Application Laid-Open No. 10-193992

By the way, conventionally, when the engine is stopped (when the ignition switch is turned on), the remaining amount of fuel is sequentially calculated. When the engine is stopped (when the ignition switch is turned off), the remaining fuel calculated immediately before the engine is stopped is calculated. When the engine is started next time while holding the amount value, the detected value of the remaining amount of fuel (display on the fuel gauge) is updated.
For this reason, even if refueling is performed while the engine is stopped, if the engine is not restarted (if the ignition switch is not turned on), the change in the remaining fuel amount due to refueling is not calculated, and the remaining amount detection result different from the actual result There was a problem of being held in.

In addition, in order to avoid being affected by changes in the liquid level that are unrelated to the change in the remaining amount, a smoothing process is often performed in the detection of the remaining amount of fuel. As a result, there is a problem that the actual remaining amount is not detected immediately after the engine is restarted.
The present invention has been made in view of the above problems, and can detect a change in the remaining amount of fuel immediately in response to refueling while the engine is stopped. An object of the present invention is to provide a fuel remaining amount calculation device for a vehicle capable of detecting the remaining amount.

Therefore, the fuel remaining amount calculating apparatus for a vehicle according to the first aspect of the invention calculates a remaining fuel amount by inputting a detection signal from the fuel level gauge while the engine is stopped, and outputs and / or stores the calculated result. I do.
According to this configuration, even when the engine is stopped, a detection signal from the fuel level gauge is input to calculate the remaining amount of fuel, and the calculation result is output and / or stored.

Accordingly, the remaining amount information can be immediately updated for refueling while the engine is stopped, and the remaining amount can be detected from the actual fuel remaining amount as an initial value from the time of restarting the engine.
According to the second aspect of the present invention, the engine shifts to the low power consumption mode except when fuel is supplied to the fuel tank while the engine is stopped, and returns to the normal mode when fueling to calculate the remaining amount of fuel.
According to such a configuration, when the engine is stopped, the system stands by in the low power consumption mode except during refueling, and when refueling is performed, the normal mode is restored to calculate the remaining fuel amount normally.

Therefore, power consumption when the engine is stopped can be suppressed, and battery consumption can be suppressed.
In the invention according to claim 3, the fuel supply state is determined based on the opening of the fuel filler lid and / or the fuel supply cap of the fuel tank.
According to this configuration, it is determined whether or not fuel can be supplied based on whether or not the fuel filler lid and / or the fuel cap of the fuel tank is opened, and the low power consumption mode and the normal mode are determined. When the mode is switched to normal mode, the remaining fuel amount is calculated.

  Therefore, it is possible to accurately determine the refueling that will be performed on the premise that the fuel filler lid and the refueling cap are opened, and to switch the mode, ensuring the calculation of the remaining amount during refueling while maximizing power consumption. Can be done.

Embodiments of the present invention will be described below.
The system configuration of the vehicle engine in the embodiment is shown in FIG.
In FIG. 1, an engine 1 is a gasoline internal combustion engine, and air is sucked into a combustion chamber 4 through a throttle valve 2 and an intake valve 3, while fuel is injected from a fuel injection valve 5, thereby causing a combustion chamber. An air-fuel mixture is formed in 4.

The air-fuel mixture in the combustion chamber 4 is ignited and burned by spark ignition by the spark plug 6, and the combustion exhaust is discharged from the combustion chamber 4 through the exhaust valve 7.
The fuel injection valve 5 is supplied with fuel (gasoline) in a fuel tank 10 mounted on the vehicle together with the engine 1.
A fuel pump 11 is installed in the fuel tank 10, and fuel sucked by the fuel pump 11 is supplied to the fuel injection valve 5 through a fuel supply pipe (not shown).

The fuel tank 10 includes a mechanical valve 25 for releasing the pressure when the pressure in the tank becomes abnormally high, or a mechanical valve for closing the tank when the fuel is full. 26 etc. are provided.
Fuel injection by the fuel injection valve 5 and ignition by the spark plug 6 are controlled by an engine control module (hereinafter referred to as ECM) 12.

The ECM 12 includes a microcomputer, receives detection signals from various sensors, determines a fuel injection timing and a fuel injection amount by arithmetic processing based on the detection signals, and sends an injection control signal to the fuel injection valve. 5, the ignition timing is determined, and the ignition control signal is output to the power transistor that controls the energization of the ignition coil.
As the various sensors, an air flow meter 31 for detecting the intake air amount of the engine 1 on the upstream side of the throttle valve 2, a crank angle sensor 32 for detecting the rotation angle of the crankshaft, and the like are provided.

Further, an evaporative fuel processing device 15 for processing fuel vapor generated in the fuel tank 10 is provided.
The evaporative fuel processing device 15 once collects the fuel vapor generated in the fuel tank 10 by adsorbing it on the adsorbent (activated carbon) in the canister 17 via the fuel vapor introduction path 16 and removes it from the canister 17. The separated fuel vapor is supplied to the intake passage on the downstream side of the throttle valve 2 of the engine 1 through the purge passage 18.

The canister 17 is formed with a fresh air introduction port 17a. When the negative suction pressure of the engine 1 acts on the canister 17 through the purge passage 18, the canister 17 is caused by the fresh air introduced from the fresh air introduction port 17a. The fuel vapor adsorbed by the engine 17 is desorbed, and the desorbed fuel vapor is supplied to the engine 1 through the purge passage 18 and combusted.
A purge control valve 19, which is a normally closed solenoid valve, is interposed in the purge passage 18, and the purge flow rate is controlled by the opening degree of the purge control valve 19.

The fresh air introduction port 17a is provided with an atmospheric release valve 20, which is a normally closed solenoid valve. When purging is performed, the atmospheric release valve 20 is controlled to open and the purge control valve 19 is opened. The purge is performed by adjusting the opening degree of.
When the purge control valve 19 and the atmosphere release valve 20 are closed, the area including the fuel tank 10, the fuel vapor introduction passage 16, the canister 17, and the purge passage 18 upstream of the purge control valve 19 is closed. A pressure sensor 21 is provided for detecting the pressure (tank pressure) in the closed area.

The fuel pump 11, purge control valve 19, and air release valve 20 are controlled by a fuel system control module (hereinafter referred to as FCM) 22.
The FCM 22 includes a microcomputer, and is configured to be capable of mutual communication with the ECM 12. The FCM 22 inputs a detection signal of the pressure sensor 21, detects a detection signal of the fuel level gauge 23, and supplies fuel to the fuel tank 10. A signal of the open / close switch 24 for detecting the open / closed state of the fuel filler cap 27 (or the fuel filler lid 28) of the mouth is input.

The FCM 22 receives the purge request signal from the ECM 12 and controls the purge control valve 19 and the atmosphere release valve 20 to perform the purge process, and also detects the blockage area (pressure detection) from the detection result of the pressure sensor 21. A leak diagnosis in the area) is performed, and the result of the leak diagnosis and information on the remaining fuel amount are transmitted to the ECM 12.
The leak diagnosis is performed based on, for example, a pressure increase characteristic in an area closed by the purge control valve 19 and the atmosphere release valve 20 immediately after the engine is stopped, and further, the pressure increased to a predetermined pressure. This is based on the pressure drop characteristics in a confined state.

  In addition, an air pump for supplying and pressurizing air in the closed area is provided, and air is supplied and pressurized in the closed area in a state where the fuel temperature is sufficiently lowered after the engine is stopped. The leak diagnosis can be performed based on the rising characteristic of the tank, and further, the leak diagnosis can be performed based on the pressure decreasing characteristic after stopping the pressurization of the tank internal pressure that has been raised to a predetermined value by the air pump.

Further, by opening the purge control valve 19 while the air release valve 20 is closed during engine operation, the tank is made negative pressure, and in this negative pressure state, the purge control valve 19 is closed and the negative pressure is confined. The leak diagnosis can be performed based on the pressure drop characteristic.
Further, the FCM 22 has a function of calculating the remaining amount of fuel even when the engine is stopped in order to detect an increase change in the remaining amount of fuel due to refueling. In order to realize this, the battery power is continuously supplied to the FCM 22 even after the ignition switch is turned off.

The flowchart of FIG. 2 shows a first embodiment of the remaining amount calculation process while the engine is stopped by the FCM 22.
The routine shown in the flowchart of FIG. 2 is executed every predetermined time. First, in step S1, it is determined whether or not the engine is stopped.
The determination of the engine stop can be made based on an engine rotation signal transmitted from the ECM 12 or an ignition switch signal.

If the engine is in operation, the process proceeds to step S2, the normal mode is set, and in the next step S3, the processing function of the FCM 22 including the calculation of the remaining amount of fuel is operated normally.
The normal mode indicates that all the original functions of the FCM 22 are maintained in a normal state without saving power consumption.
Further, in the calculation of the remaining amount of fuel, the detection signal of the fuel level gauge 23 is used so that the detection result of the remaining amount does not fluctuate greatly due to the change in the liquid level due to the acceleration in the longitudinal direction and the lateral direction of the vehicle. The fuel remaining amount data calculated by the annealing process is stored, and the calculated remaining fuel amount data is output to the fuel gauge 30 and the ECM 12 side.

On the other hand, if it is determined in step S1 that the engine is stopped, the process proceeds to step S4.
In step S4, it is determined on the basis of the signal from the open / close switch 24 whether or not the fuel cap 27 is open.
In step S4, it may be determined whether or not the fuel filler lid 28 is in an open state in place of the fuel filler cap 27, and whether or not both the fuel filler cap 27 and the fuel filler lid 28 are in an open state. It may be judged.

If it is determined in step S4 that the refueling cap 27 is not in an open state, that is, if it is determined that the engine is stopped and not in a refueling state, the process proceeds to step S5 and shifts to the low power consumption mode.
The low power consumption mode indicates that the microcomputer in the FCM 22 is in a low power consumption state. In the low power consumption mode, the determination function and the mode switching function in steps S1 and S4 operate, but the fuel level In this mode, operating power cannot be supplied to the gauge 23 to newly calculate the remaining amount of fuel.

When refueling, first, the fuel filler lid 28 is opened, then the refueling cap 27 is opened, and the refueling gun is inserted into the refueling port to perform refueling. Therefore, the refueling is performed with the refueling cap 27 closed. Never done.
Therefore, when the engine is stopped and the fuel supply cap 27 is closed, the remaining amount of fuel in the fuel tank 10 does not change, and a new remaining amount calculation process is not required. Continued operation in the normal mode unnecessarily increases power consumption.

Therefore, in a situation where refueling is not performed, the FCM 22 is set in the low power consumption mode to save power consumption. As described later, when the fuel can be refueled, the normal mode is restored. Periodic calculation processing of the remaining amount of fuel is performed.
When the low power consumption mode is set in step S5, for example, when a leak diagnosis request is generated, the FCM 22 returns to the normal mode and performs a leak diagnosis.

On the other hand, if it is determined in step S4 that the refueling cap 27 is in an open state, that is, if it is determined that the engine is stopped and refueling can be performed, the process proceeds to step S6 to enter the normal mode. Transition.
In the next step S7, operating power is supplied to the fuel level gauge 23 to calculate the remaining amount of fuel periodically.

Here, when refueling is performed as the refueling cap 27 is opened, the remaining amount of fuel increased by refueling is calculated, and a change in the remaining amount due to refueling can be detected immediately without waiting until the engine is restarted.
Therefore, when the engine is restarted, the actual fuel remaining amount after refueling can be used as an initial value to start the remaining amount measurement, and the detected value (displayed on the fuel gauge) and the actual value are greatly different. There is nothing.

In addition, when returning to the normal mode and periodically calculating the remaining amount of fuel, an open drive signal is simultaneously output to the atmosphere release valve 20 to open the fuel tank 10 to the atmosphere via the canister 17. By doing so, the increase in tank internal pressure accompanying refueling is suppressed, and refueling up to full tank can be performed.
If calculation of the remaining amount of fuel is not performed, the output of the open drive signal to the atmosphere release valve 20 is also stopped, so that the open drive signal is not continuously output unnecessarily, and the engine is stopped from this point as well. Power consumption is saved.

When the fuel cap 27 is closed again after the fuel cap 27 is opened, it is determined that the fuel supply is completed, and the mode is shifted from the normal mode to the low power consumption mode.
Note that once the refueling cap 27 is opened while the engine is stopped, it is assumed that refueling will not be performed again, and the operation is completely performed until the FCM 22 shuts off the power supply and then the ignition switch is turned on. Can be stopped.

Further, when the latest calculated remaining fuel amount is equal to or greater than a predetermined amount, it is determined that refueling will not be performed, and the operation is completely performed until the FCM 22 self-shuts off the power and then the ignition switch is turned on. Can be stopped.
The flowchart of FIG. 3 shows a second embodiment of the remaining amount calculation process while the engine is stopped by the FCM 22.

In the second embodiment shown in the flowchart of FIG. 3, if the refueling cap 27 is kept open for a predetermined time or longer, it is determined that the refueling has already been completed even if refueling is performed, and the consumption is forcibly reduced. The point of shifting to the power mode is different from the first embodiment shown in the flowchart of FIG.
First, in step S11, it is determined whether or not the fuel filler cap 27 is in an open state.

If the fuel cap 27 is closed, the process proceeds to step S12, and the value of the timer t is reset to zero.
On the other hand, when the refueling cap 27 is in the open state, the process proceeds to step S13, and the value of the timer t is counted up.
In step S14, it is determined whether or not the engine is stopped. If the engine is in operation, the process proceeds to step S15 to set the normal mode. In the next step S16, various types of calculation including calculation of the remaining amount of fuel are performed. The calculation process is normally performed.

On the other hand, when the engine is stopped, the routine proceeds from step S14 to step S17, where it is determined whether or not the fuel cap 27 is opened.
When the fueling cap 27 is closed, the process proceeds to step S18 and shifts to the low power consumption mode.
When the fuel cap 27 is in the open state, the process proceeds to step S19, where it is determined whether or not the time measured by the timer t, that is, the duration of the state in which the fuel cap 27 is open is equal to or greater than the determination value. To do.

The determination value is set in advance as a time that does not exceed the time measured by the timer t in a normal refueling operation. If the time is within the determination value, refueling may be performed. Determination is made and the process proceeds to step S20.
In step S20, the mode is changed to the normal mode, and in the next step S21, the remaining amount of fuel is periodically calculated and the open valve 20 is opened.

On the other hand, when the time measured by the timer t is equal to or greater than the determination value, the process proceeds to step S18, and even if the fueling cap 27 is open, the mode is forcibly shifted to the low power consumption mode. The calculation of the remaining amount and the open control of the atmosphere release valve 20 are stopped.
Since the continuation time of the fuel supply cap 27 in the open state is not usually greater than or equal to the determination value, if the time measured by the timer t exceeds the determination value, an abnormality such as forgetting to close the fuel supply cap 27 or the like. Occurrence is estimated.

Here, if the FCM 22 is left in the normal mode based on the opening of the refueling cap 27, the power consumption during engine stop increases, so the time measured by the timer t becomes equal to or greater than the determination value. In such a case, even if refueling is performed, it is determined that it has already been completed, and the mode is forcibly shifted to the low power consumption mode.
Therefore, even if the refueling cap 27 is forgotten to be closed, it is possible to prevent the FCM 22 from being left in the normal mode and consuming a large amount of power until the next start of the engine.

Here, technical ideas other than the claims that can be grasped from the above embodiment will be described together with effects.
(A) In the vehicle fuel remaining amount calculating apparatus according to claim 3,
A fuel remaining amount calculation device for a vehicle, which forcibly shifts to a low power consumption mode when the fuel filler lid and / or the fuel cap is opened for a predetermined time or longer.

With this configuration, even if you forget to close the fuel filler lid or the fuel cap, it will not be left in the normal mode, and it will save power consumption while the engine is stopped, thus preventing battery drain. can do.
(B) In the vehicle fuel remaining amount calculating apparatus according to claim 2 or 3,
A fuel for a vehicle characterized in that opening control of an air release valve interposed in a fresh air inlet of a canister that adsorbs fuel vapor generated in the fuel tank is performed together with calculation of the remaining amount of fuel in the normal mode. Remaining amount calculation device.

According to this configuration, when calculating the remaining amount of fuel when there is a possibility of refueling, at the same time, by opening the fresh air inlet of the canister to the atmosphere, an increase in tank internal pressure accompanying refueling is suppressed, and If the atmospheric release valve is a normally closed solenoid valve, the output of an open drive signal to the solenoid valve can be limited when necessary, and power consumption can be saved.
(D) In the vehicle fuel remaining amount calculating apparatus according to claim 2 or 3,
An apparatus for calculating a remaining amount of fuel for a vehicle, wherein the remaining amount of fuel is calculated in a normal mode at the time of refueling, and then power supply is cut off.

According to this configuration, once refueling is performed while the engine is stopped, it is assumed that there will be no refueling thereafter, and the power supply is self-shut off to stop operation completely, thereby eliminating power consumption after refueling. In addition, battery consumption during engine stop can be suppressed to the maximum.
Note that the process of completely shutting down the operation by shutting off the power supply can be regarded as a transition to the low power consumption mode.
(E) In the vehicle fuel remaining amount calculating apparatus according to claim 2 or 3,
A fuel remaining amount calculating apparatus for a vehicle, characterized in that when the latest calculated remaining fuel amount is greater than or equal to a predetermined amount, the power supply is cut off by itself.

  According to this configuration, if the remaining amount of fuel immediately before engine stop or after refueling is more than a predetermined amount (substantially full), it is determined that refueling will not be performed, and the power supply is shut off and the operation is completed. When the engine is stopped, it is possible to avoid waste of waiting in a state where no fuel is supplied, and to suppress the consumption of the battery while the engine is stopped to the maximum.

The system diagram of the engine in an embodiment. The flowchart which shows 1st Embodiment of the calculation process of the fuel remaining amount in embodiment. The flowchart which shows 2nd Embodiment of the calculation process of the fuel remaining amount in embodiment.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 1 ... Engine, 10 ... Fuel tank, 11 ... Fuel pump, 12 ... Engine control module (ECM), 15 ... Evaporative fuel processing apparatus, 16 ... Fuel vapor introduction path, 17 ... Canister, 17a ... Fresh air inlet, 18 ... Purge passageway, 19 ... Purge control valve, 20 ... Air release valve, 24 ... Open / close switch, 22 ... Fuel system control module (FCM), 27 ... Fuel filler cap, 28 ... Fuel filler lid, 30 ... Fuel meter

Claims (3)

A fuel remaining amount calculation device for a vehicle that inputs a detection signal from a fuel level gauge that detects a fuel level in a fuel tank,
A fuel remaining amount calculation device for a vehicle, wherein a detection signal from the fuel level gauge is inputted to calculate a remaining amount of fuel while the engine is stopped, and the calculation result is output and / or stored. 2. The fuel for a vehicle according to claim 1, wherein the engine shifts to a low power consumption mode except when refueling the fuel tank while the engine is stopped, and returns to the normal mode when refueling to calculate the remaining amount of fuel. Remaining amount calculation device. The fuel remaining amount calculation device for a vehicle according to claim 2, wherein the fuel supply state is determined based on a fuel filler lid and / or an opening of a fuel cap of the fuel tank.

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