JP2007092658A - Electric power securing device of evaporated fuel processing system - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a device capable of determining the possibility of the performance of a diagnosis of stopping time leakage on the basis of an estimated charging quantity by estimating the charging quantity of a battery from a vehicle operation state. <P>SOLUTION: This electric power securing device of an evaporated fuel processing system 100 purges evaporated fuel generated by evaporating fuel in a fuel tank 10 to an intake passage 2 in response to an operation condition of an engine 1. This electric power securing device has a leakage diagnosing means for detecting leakage of the evaporated fuel from the inside of the evaporated fuel processing system 100 when stopping the engine 1, the battery for supplying electric power to an apparatus used for diagnosing the leakage, a charging quantity estimating means for estimating the charging quantity charged to the battery, and a determining means for determining the possibility of the performance of the diagnosis of the leakage by comparing the estimated charging quantity with a preset predetermined value. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to an evaporative fuel processing system for processing evaporative fuel generated by evaporating fuel in a fuel tank, and particularly an apparatus for securing electric power at the time of leak diagnosis.

  In the evaporative fuel processing system, the evaporative fuel generated in the fuel tank is temporarily adsorbed by the adsorbent of the canister. By opening the purge control valve according to the operating conditions, the adsorbed evaporated fuel is introduced into the intake system of the engine by the intake negative pressure of the engine together with fresh air, burned, and evaporated fuel generated in the fuel tank Prevents from spreading into the atmosphere.

  In the evaporative fuel processing system as described above, a system composed of a purge control valve, a canister, and a fuel tank (hereinafter referred to as an evaporation system) is hermetically closed by closing the purge control valve and the air release valve. A leak diagnosis is performed to detect a leak from the change in pressure in the system. If the oil supply port is opened during refueling diagnosis due to refueling or the like, the evaporation system internal pressure is close to the atmospheric pressure as in the case of the occurrence of a leak, and there is a possibility that a misdiagnosis may occur if there is a leak in the evaporation system.

In Patent Document 1, the presence or absence of refueling is detected based on a change in the remaining amount of fuel at each stop, and when it is determined that there is refueling, the power supply to each device required for the leak diagnosis at stop is interrupted. Devices have been proposed that reduce the consumption of energy.
JP 2004-278409 A

  However, in the above-described leak diagnosis device, if it is determined that the fuel is not supplied, the diagnosis is performed even when the battery charge amount does not secure the power necessary for the leak diagnosis, which is necessary at the next start-up. There is a problem that the amount of charge cannot be secured.

  The present invention has been made in view of the above-described problems, and an object of the present invention is to provide an apparatus that can determine whether or not the leakage diagnosis at the time of stopping can be performed based on the charge amount of the battery.

  The present invention is an electric power securing device for an evaporated fuel processing system that purges evaporated fuel generated by evaporation of fuel in a fuel tank to an intake passage according to engine operating conditions. The power securing device includes a leak diagnosis unit that detects a leak of evaporated fuel from the evaporated fuel processing system when the engine is stopped, a battery that supplies power to a device used for the leak diagnosis, and a charge that is charged in the battery. It is characterized by comprising a charge amount estimating means for estimating the amount and a determination means for determining whether or not the leakage diagnosis can be performed by comparing the estimated charge amount with a set predetermined value.

  According to the present invention, when it is determined that the power necessary for performing the leak diagnosis is not secured in the battery, the leak diagnosis at the time of stopping is not performed, so the standby power of each device before diagnosis and the power consumption at the time of diagnosis are reduced. Therefore, it is possible to always secure the amount of battery power required at the next start.

  Embodiments of the present invention will be described below with reference to the drawings.

(First embodiment)
FIG. 1 is a configuration diagram of an evaporated fuel processing system 100 according to a first embodiment of the present invention. Reference numeral 1 denotes an engine, 2 denotes an intake passage of the engine 1, and 3 denotes an exhaust passage. The intake passage 2 is provided with an intake air amount sensor 4 that detects the intake air amount and a throttle valve 5 that is located downstream of the intake passage 2 and controls the intake air amount. Furthermore, a fuel injection valve 6 that is located downstream of the throttle valve 5 and injects fuel is installed in the intake passage 2. Fuel is injected from the fuel injection valve 6 according to the amount of intake air, and the engine 1 generates an output by burning the fuel / air mixture in the engine 1.

  A fuel tank 10 stores fuel to be supplied to the engine 1 for temporarily adsorbing and holding the evaporated fuel generated in the fuel tank 10 and for sucking the evaporated and held fuel into the engine 1 according to vehicle operating conditions. An evaporative fuel processing system 100 is provided.

  The evaporative fuel processing system 100 includes a canister 12 filled with activated carbon that adsorbs and holds evaporative fuel. The canister 12 is connected to the fuel tank 10 via the first passage 11 and adsorbs and holds the evaporated fuel generated in the tank. In addition, an air release valve 8 that adjusts the introduction of fresh air from the atmosphere communication passage 19 that communicates with the atmosphere is provided above the canister 12. Further, the canister 12 is connected to one end of the second passage 13 at an upper portion thereof. The other end of the second passage 13 is connected to a downstream position of the throttle valve 5 in the intake passage 2, and a purge control valve 7 for adjusting the amount of fuel vapor introduced is provided in the middle. Between the purge control valve 7 and the canister 12, a pressure sensor 9 for measuring the pressure in the evaporation system of the evaporated fuel processing system 100 is provided, and the measured pressure is output to the controller 20 described later.

  The fuel tank 10 includes a fuel pump 18 for pumping fuel. The fuel pump 18 is connected to the fuel injection valve 6 through the fuel supply channel 14. Accordingly, the fuel is discharged to the fuel supply path 14 by the fuel pump 18 and is held at a constant pressure by a regulator (not shown), and this fuel pressure acts on the fuel injection valve 6. The fuel tank 10 is provided with a fuel supply pipe 16 for fueling. A detachable filler cap 15 is attached to the oil supply port of the oil supply pipe 16. At the time of fuel supply, the filler cap 15 is removed and fuel supply is performed. A circulation path 17 is branched and connected to the fuel supply pipe 16, and the opening end of the circulation path 17 opens into the upper space of the fuel tank 10.

  The controller 20 includes a CPU, ROM, RAM, and the like (not shown), and includes a pressure sensor 9, an ignition switch 21, a vehicle speed sensor 22, an engine speed sensor 23, a battery voltage sensor 24, an alternator speed sensor 25, and a radiator fan applied current sensor. 26, and outputs of other sensors for detecting the driving state of the vehicle (not shown).

  Further, the controller 20 opens the purge control valve 7 and the air release valve 8 according to the vehicle operating state, thereby causing the negative pressure of the engine 1 to act on the evaporation system, and the evaporated fuel adsorbed by the canister 12 Purge control is performed for introducing air into the intake passage 2 together with fresh air from the atmosphere communication passage 19.

  Further, when the vehicle is stopped, the purge control valve 7 and the atmosphere release valve 8 are controlled to open and close, and the leak diagnosis in the evaporation system is performed based on the output of the pressure sensor 9.

  In the stop-time leak diagnosis, the purge control valve 7 and the atmosphere release valve 8 are closed to seal the inside of the evaporation system, and the pressure sensor 9 detects the pressure change due to the fuel temperature change in the fuel tank 10. When there is a leak in the evaporation system, the pressure change due to the temperature change is small, and the pressure value detected by the pressure sensor 9 is close to the atmospheric pressure. Then, the occurrence of a leak in the evaporation system is diagnosed by comparing the pressure change amount changed for a predetermined time required for leak diagnosis, for example, about 40 to 50 minutes, with the set predetermined value. If leakage is confirmed, the driver is warned at the next start.

  Since such leak diagnosis is performed when the vehicle is stopped, if the amount of charge current of the battery is not sufficiently secured, the necessary amount of power cannot be secured at the next start, and an inadvertent battery rise may occur. There is sex.

  Therefore, the operation for securing electric power in the stoppage leakage diagnosis performed by the controller 20 will be described with reference to FIGS. 2 and 3, respectively.

  The process for securing electric power in the first embodiment is executed together with the start of operation of the internal combustion engine of the vehicle based on a signal from the ignition switch 23, and is performed at a constant cycle.

  First, in step S101, time measurement from the start of processing is started by timer increment.

In step S102, the charge / discharge current value A to the battery is calculated by the following formula using parameters detected by various sensors. As parameters, vehicle speed, engine speed, battery voltage, alternator speed, and current applied to the radiator fan are detected.
Charge / discharge current value A
= C ₁ × vehicle speed + C ₂ × engine speed + C ₃ × battery voltage + C ₄ × alternator speed + C ₅ × current applied to the radiator fan + C ₆ (1)

The expression (1) is an expression obtained by performing multiple regression analysis on each parameter, and C ₁ to C ₆ are coefficients set from a prior experiment or the like. A charging current value for charging the battery is calculated from the vehicle speed, engine speed, battery voltage, and alternator speed, and a discharging current value for discharging from the battery is calculated from the current applied to the radiator fan. Therefore, the charge / discharge current value A is obtained by the sum of the charge current value and discharge current value of these batteries.

  As shown in FIG. 3A, the charging / discharging current value A varies depending on the driving situation of the vehicle and is constantly monitored. When the charge / discharge current value A is a positive value, it means that the battery is charged, and when it is a negative value, it means that the battery is discharged.

  In addition to the above parameters, the value of the applied current used in other devices may be added to the equation (1) as a parameter. That is, by adding the current applied to the window, light, air conditioner, seat heater, etc. as a parameter, a more detailed charge / discharge current value A can be calculated. Further, instead of detecting the applied current, the charge / discharge current value may be calculated by detecting the drive switch of each device.

In step S103, the calculated charge / discharge current value A is integrated to calculate the charge current amount V _total to the battery. By calculating the charge current amount V _{total according} to the following formula, it is possible to detect the state of the battery such as how much the battery has been charged.
V _total = V _total + A (2)

After calculating the charge current amount V _total, at step S104, it determines the time measured by the timer increment whether greater than the predetermined determination time t _1. If it does not meet the determination time t ₁ repeats the processing of steps S102, S103 until satisfying the determination time. If the determination time t ₁ is satisfied, it is determined whether or not the charge current amount V _total is larger than a predetermined threshold value V ₁ (step S105).

As shown in FIG. 3 (B), when the charge current value V _total obtained by integrating charge and discharge current value A is larger than the predetermined threshold value V ₁ was, and ends the processing permission stop leak diagnosis at step S106. If the charge current value V _total does not satisfy the condition, the stop leak diagnosis is not permitted in step S107 and the process is terminated.

If the leak diagnosis at the time of stop is permitted by the above processing, the leak diagnosis is performed under a predetermined condition after confirming that the internal combustion engine has stopped. On the other hand, if the charge current amount V _total of the battery is insufficient and the leak diagnosis at stop is not allowed, the power to each device used for the stop leak diagnosis when stopping the internal combustion engine without performing the leak diagnosis Stop supplying.

  As described above, in the first embodiment, it is possible to determine the charge amount of the battery before the leak diagnosis by calculating the charge current amount of the battery after a predetermined time has elapsed. As a result, when it is determined that the power required for the leak diagnosis is not secured, the leakage diagnosis during stoppage is not performed, and standby power of each device before diagnosis and power consumed at the time of diagnosis can be suppressed. This makes it possible to always ensure the battery power required at the next start.

  In addition, since each current value is detected using an existing sensor and the amount of charge current is calculated, it is possible to determine whether to secure battery power without adding a new device, thereby reducing costs.

(Second Embodiment)
A second embodiment of the present invention will be described with reference to the flowchart shown in FIG. The configuration of the second embodiment is the same as that of the first embodiment, but is partially different at the determination time of the charge current value V _total by the controller 20. That is, in the second embodiment, the charge current value V _total is determined after the internal combustion engine is stopped by Key Off, and the difference will be described below.

  The electric power securing process in the second embodiment is started together with the operation of the internal combustion engine of the vehicle by a signal from the ignition switch 23, and is performed at a constant cycle.

As in the first embodiment, in step S201 and step S202, the charge / discharge current value A to the battery is calculated by the equation (1), and the charge / discharge current value A is integrated by the equation (2), thereby charging current. The amount V _total is calculated.

In step S203, it determines whether or not the engine of the vehicle is stopped by a signal from an ignition switch 23, also the charge current amount V _total computed during driving if stop is confirmed than the predetermined threshold value V ₁ It is determined whether it is larger (step S204). If the stop of the internal combustion engine is not confirmed, the processes of step S201 and step S202 are repeated until the stop is confirmed.

If the charge current amount V _total satisfies the condition, the stop leak diagnosis is permitted in step S205, and if the condition is not satisfied, the leak diagnosis is not permitted in step S206 and the process is terminated. The stop-time leakage diagnosis performed after this processing is the same as in the first embodiment.

As described above, in the second embodiment, since the charge current amount V _total is compared with the predetermined threshold value V ₁ every time one trip is completed, the latest value is always used when determining the charge current amount V _total. Can be determined. As a result, not only the same effects as in the first embodiment can be obtained, but also the state of the battery can be grasped more accurately, so that the possibility of erroneous determination in whether or not leakage diagnosis can be performed can be reduced, and the determination accuracy can be improved. Can be planned.

  The present invention is not limited to the above-described embodiment, and it is obvious that various modifications can be made within the scope of the technical idea.

  INDUSTRIAL APPLICABILITY The present invention can be used in an apparatus that is mounted on a vehicle and that processes evaporated fuel generated by evaporation of fuel in a fuel tank.

It is a block diagram of the evaporative fuel processing system which concerns on the 1st and 2nd embodiment of this invention. It is a flowchart which shows operation | movement of the electric power securing apparatus which concerns on the 1st Embodiment of this invention. It is a time chart which shows the charge / discharge current value and charge current amount which are calculated in the 1st and 2nd embodiment of this invention. It is a flowchart which shows operation | movement of the electric power securing apparatus which concerns on the 2nd Embodiment of this invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 100 Evaporative fuel processing system 1 Engine 2 Intake passage 7 Purge control valve 8 Atmospheric release valve 9 Pressure sensor 10 Fuel tank 12 Canister 19 Atmospheric communication passage 20 Controller 21 Ignition switch 22 Vehicle speed sensor 23 Engine speed sensor 24 Battery voltage sensor 25 Alternator rotation Number sensor 26 Radiator fan applied current sensor
S102 to S103, S201 to S202 Charge amount estimation means
S105 to S107, S204 to S206 Judgment means
S102, S201 Current value calculation means
S103, S202 Charge current amount calculation means

Claims (5)

In an evaporative fuel processing system for purging evaporative fuel generated by evaporation of fuel in a fuel tank to an intake passage according to engine operating conditions,
Leak diagnosis means for detecting leakage of the evaporated fuel from the evaporated fuel processing system when the engine is stopped;
A battery for supplying power to the device used for the leak diagnosis;
A charge amount estimating means for estimating a charge amount charged in the battery;
A power securing device for an evaporative fuel processing system, comprising: a determination unit that determines whether or not the leak diagnosis can be performed by comparing the estimated charge amount with a set predetermined value. The determination means includes
The estimated charge amount is compared with a set predetermined value after a predetermined time has elapsed from the start of driving of the vehicle, and if it is larger than the predetermined value, the leakage diagnosis is permitted, and if it is less than the predetermined value, the leak The power securing device for an evaporated fuel processing system according to claim 1, wherein the power supply is cut off by disabling the execution of diagnosis. The determination means includes
When the vehicle is stopped, the estimated charge amount is compared with a set predetermined value, and if it is larger than the predetermined value, the execution of the leak diagnosis is permitted, and if it is less than the predetermined value, the execution of the leak diagnosis is not permitted. The power securing device for an evaporative fuel processing system according to claim 1, wherein the power supply is cut off. The charge amount estimating means includes
Current value calculating means for calculating a charge / discharge current value to the battery from a driving state of the vehicle;
The evaporation according to any one of claims 1 to 3, further comprising charge current amount calculation means for calculating a charge current amount charged in the battery by integrating the calculated current values. A power securing device for a fuel processing system. The current value calculating means includes
A detection means for detecting the vehicle speed, the engine speed, the alternator speed, the battery voltage, and the current applied to the radiator fan of the vehicle;
The charge / discharge current value is calculated by calculating a charge current value and a discharge current value of the battery from the detected parameter values, and summing them. Electric power securing device for an evaporative fuel processing system.

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