JP2018013110A - Evaporated fuel treatment device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a technology to determine a purge concentration while considering delay between timing when the purge concentration is specified and timing of arrival at an internal combustion engine.SOLUTION: An evaporated fuel treatment device includes a memory having 300 storage regions 104a from 1st to 300th, and a control portion. The control portion stores a purge concentration of purge gas positioned in a Kth section obtained by dividing a purge passage 24 in which the purge gas flows between a canister 14 and a control valve 34, into 300 sections from 1st to 300th successively from the canister 14 to the control valve 34, in the Kth storage region 104a among 300 storage regions 104a, the purge concentration stored in the storage regions 104a from Mth to 1st is moved from 300th to 300-M+1th according to flow of the purge gas, and the specified purge concentration is stored in the storage regions 104a from the 300-Mth to 1st.SELECTED DRAWING: Figure 2

Description

  This specification discloses the technique regarding an evaporative fuel processing apparatus. In particular, an evaporative fuel processing device is disclosed in which evaporative fuel generated in a fuel tank is supplied to an internal combustion engine via an intake path of the internal combustion engine by a purge process.

  The evaporated fuel processing apparatus includes a canister that adsorbs and stores evaporated fuel generated in a fuel tank, and a control valve that is disposed on a purge path that connects the canister and the intake path. The control valve is switched between a communication state in which the canister and the intake path communicate with each other and a shut-off state in which the canister and the intake path do not communicate with each other. When the control valve is in communication, purge gas in which evaporated fuel and air in the canister are mixed passes through the purge path and intake path and is supplied to the internal combustion engine. For this reason, the air-fuel ratio of the internal combustion engine changes depending on the supply amount of the evaporated fuel to the internal combustion engine. Therefore, in order to adjust the air-fuel ratio of the internal combustion engine to a predetermined air-fuel ratio, it is required to specify the concentration of evaporated fuel in the purge gas (hereinafter referred to as “purge concentration”).

  Patent Document 1 discloses a technique for specifying the purge concentration. The evaporative fuel processing apparatus of Patent Document 1 specifies the purge concentration using the air-fuel ratio of the internal combustion engine.

JP 2003-83114 A

  When the purge concentration is specified using the air-fuel ratio, the purge concentration is estimated based on a deviation from the predetermined air-fuel ratio, and the predetermined air-fuel ratio is set based on the estimated purge concentration. , Adjust the fuel injection amount from the injector. When the air-fuel ratio deviates from a predetermined value, the estimated purge concentration is corrected. Thereafter, the purge concentration is specified by repeatedly executing the adjustment of the fuel injection amount and the correction of the purge concentration until a predetermined air-fuel ratio is reached.

  In order to specify the purge concentration more accurately, a technique for specifying the purge concentration using the purge gas before the purge gas flows into the intake passage and mixes with air has been developed. In this technique, the position where the purge concentration is specified is separated from the internal combustion engine. For this reason, the timing at which the purge gas having the specified purge concentration reaches the internal combustion engine is delayed from the timing at which the purge concentration is specified. The present specification provides a technique for determining the purge concentration in consideration of a delay between the timing at which the purge concentration is specified and the timing at which the purge concentration arrives at the internal combustion engine.

  The evaporated fuel supply device disclosed in this specification is mounted on a vehicle. The evaporative fuel processing device is disposed on a purge path that connects the canister for adsorbing the evaporated fuel in the fuel tank and the intake path and the canister of the internal combustion engine, and communicates the canister and the intake path via the purge path. A control valve that switches to a communicating state that shuts off the canister and the intake path on the purge path, a specifying unit that repeatedly specifies the fuel vapor concentration of the purge gas at a specific position from the canister to the control valve, and a specifying And a determining unit that determines the evaporated fuel concentration at a determined position located closer to the internal combustion engine than the specified position using the evaporated fuel concentration specified at the position. The determination unit includes a memory having first to L L first storage areas (L is an integer of 2 or more) and a memory control unit. The memory control unit has a path through which the purge gas flows between the specific position and the determined position in the first storage area of the Kth (K is an integer of 1 ≦ K ≦ L) among the L first storage areas. The evaporated fuel concentration of the purge gas located in the Kth section when the specific position to the determined position are divided into L sections from No. 1 to L in order is stored, and the purge gas is located between the specified position and the determined position. The fuel vapor concentration stored in the first storage area from No. M (M is an integer of 1 ≦ M ≦ L) to No. 1 in accordance with the purge gas flow is The value obtained using the evaporated fuel concentration specified last by the specifying unit is stored in the first storage area from No. LM to No. 1 in the first storage area. The fuel vapor concentration stored in the first storage area is determined as the fuel vapor concentration at the determined position. To.

  In this configuration, the evaporated fuel concentration of the purge gas, that is, the purge concentration is specified at a specific position on the purge path. In the memory, the purge concentration from the specific position to the determined position is stored in L pieces, and the purge concentration in the memory is shifted according to the flow of the purge gas. As a result, the purge concentration at the determined position can be determined using the purge concentration stored corresponding to the determined position in the memory. According to this configuration, the purge concentration at the determination position closer to the internal combustion engine than the specific position can be determined in consideration of the delay until the purge gas positioned at the specific position reaches the determination position.

  Another evaporated fuel supply device disclosed in the present specification is mounted on a vehicle. The evaporative fuel processing device is disposed on a purge path that connects the canister for adsorbing the evaporated fuel in the fuel tank and the intake path and the canister of the internal combustion engine, and communicates the canister and the intake path via the purge path. A control valve that switches to a communicating state that shuts off the canister and the intake path on the purge path, a specifying unit that repeatedly specifies the fuel vapor concentration of the purge gas at a specific position from the canister to the control valve, and a specifying And a determining unit that determines the evaporated fuel concentration at a determined position located closer to the internal combustion engine than the specified position using the evaporated fuel concentration specified at the position. The determining unit includes a memory having first to B B storage areas (B is an integer equal to or greater than 2) and a memory control unit. The memory control unit moves the evaporated fuel concentration stored in the first storage area from No. 1 to B-1 to the first storage area from No. 2 to B every time the evaporated fuel concentration is specified. The specified fuel vapor concentration is stored in the first storage area No. 1, and the determining unit is adapted to the flow of the purge gas when the purge gas is flowing in the path between the specified position and the determined position. Out of the fuel vapor concentrations stored in the first storage area from No. 1 to B, the fuel vapor concentration stored in the first storage area of No. C (an integer of 1 ≦ C ≦ B) is determined last time. The fuel vapor concentration at the determined position is determined using the fuel vapor concentration at the determined position.

  In this configuration, the evaporated fuel concentration of the purge gas, that is, the purge concentration is specified at a specific position on the purge path. In the memory, B purge concentrations having different specific timings are stored. The purge concentration at the determined position is determined using the C-th purge concentration in accordance with the flow of the purge gas and the previously determined purge concentration among the B purge concentrations in the memory. According to this configuration, the purge concentration at the determination position closer to the internal combustion engine than the specific position can be determined in consideration of the delay until the purge gas positioned at the specific position reaches the determination position.

1 shows an outline of a fuel supply system for an automobile according to a first embodiment. The schematic diagram for demonstrating the correspondence of the purge path | route and memory of 1st Example is shown. The schematic diagram for demonstrating the correspondence of the path | route from the control valve of 1st Example to an engine, and memory is shown. The flowchart of the upstream determination process of 1st Example is shown. The flowchart of the downstream determination process of 1st Example is shown. FIG. 3 is a schematic diagram for explaining a shift in purge concentration when the purge flow rate is small in the memory corresponding to the purge path of the first embodiment. FIG. 3 is a schematic diagram for explaining a shift in purge concentration when the purge flow rate is large in the memory corresponding to the purge path of the first embodiment. The schematic diagram for demonstrating the shift of the purge density | concentration in the memory corresponding to the path | route from the control valve of 1st Example to an engine is shown. FIG. 5 is a schematic diagram for explaining a shift in purge concentration when the purge flow rate is large in the memory corresponding to the purge path of the second embodiment. The schematic diagram for demonstrating the shift of the purge density | concentration in the memory corresponding to the path | route from the control valve of 2nd Example to an engine is shown. The flowchart of the upstream determination process of 2nd Example is shown. The flowchart of the downstream determination process of 2nd Example is shown. The graph which shows the detachment | desorption characteristic of the canister of 3rd Example is shown. 9 shows a flowchart of a correction process according to the third embodiment. 9 shows a flowchart of a purge concentration specifying process of the third embodiment.

  The main features of the embodiments described below are listed. The technical elements described below are independent technical elements and exhibit technical usefulness alone or in various combinations, and are not limited to the combinations described in the claims at the time of filing. Absent.

(Characteristic 1) In the evaporated fuel processing apparatus of the present specification, the memory control unit may store the evaporated fuel concentration specified last by the specifying unit in the first storage area from the LM number to the first number. . According to this configuration, the purge concentration can be stored in the storage area in accordance with the purge flow.

(Feature 2) In the fuel vapor processing apparatus of the present specification, the memory may further include first to X-th X storage areas (X is an integer of 2 or more). The memory control unit has a path through which purge gas flows between the determined position and the internal combustion engine in the second storage area of W number (W is an integer of 1 ≦ W ≦ X) of the X second storage areas. Stores the evaporated fuel concentration of the purge gas located in the Wth section when the specific position to the internal combustion engine is divided into X sections from the first to the Xth in order, and the purge gas is located between the determined position and the internal combustion engine. The fuel vapor concentration stored in the second storage area from No. Y (Y is an integer equal to or less than X) to No. 1 in accordance with the purge gas flow is changed from No. X to X−. Move to Y + 1 and store the value obtained by using the evaporated fuel concentration specified at the timing of moving the evaporated fuel concentration from X to XY + 1 in the second storage area from XY to # 1 The deciding unit calculates the fuel vapor concentration stored in the Xth second storage area. It may be determined as the fuel vapor concentration in an internal combustion engine. According to this configuration, the purge concentration from the specific position to the internal combustion engine can be stored in the memory. Therefore, the purge concentration in the internal combustion engine can be determined in consideration of the delay until the purge gas located at the specific position reaches the internal combustion engine.

(Characteristic 3) In the fuel vapor processing apparatus of the present specification, the memory control unit transfers the fuel vapor concentration to the second storage area from the XY number to the first storage area at the timing of moving the evaporated fuel concentration from the X number to the XY + 1 number The evaporated fuel concentration stored in the first storage area of the number may be stored. According to this configuration, the concentration can be stored in the second storage area from the XYth to the first in accordance with the flow of the purge gas.

(Feature 4) In the fuel vapor processing apparatus of the present specification, the determination unit may determine the fuel vapor concentration at the determination position by further using a coefficient determined according to the flow of the purge gas. According to this configuration, the purge concentration can be corrected using a coefficient that matches the flow of the purge gas.

(Characteristic 5) In the fuel vapor processing apparatus of the present specification, the determining unit determines the fuel vapor concentration at the previously determined determination position from the fuel vapor concentration stored in the first storage area of C number the previous time. The evaporated fuel concentration at the determined position may be determined by adding a value obtained by subtracting the evaporated fuel concentration at the already determined position and dividing by the coefficient. According to this configuration, the purge concentration at the determination position can be determined using the purge concentration at the determination position determined last time, the purge concentration stored in No. C, and the coefficient.

(Characteristic 6) In the fuel vapor processing apparatus of the present specification, the memory may further include first to D-th D storage areas (D is an integer of 2 or more). Whenever the fuel vapor concentration at the determined position is determined, the memory control unit changes the fuel vapor concentration stored in the second storage area from No. 1 to D-1 to the second storage area from No. 2 to D. The evaporative fuel concentration at the determined position is stored in the second storage area of No. 1, and the determining unit determines the purge gas when the purge gas flows from the determined position in the second path of the internal combustion engine. According to the flow, among the evaporated fuel concentrations stored in No. 1 to D No. 2 storage areas, the evaporated fuel concentration stored in No. E (integer of 1 ≦ E ≦ D) No. 2 storage area And the evaporated fuel concentration in the internal combustion engine may be determined using the previously determined evaporated fuel concentration in the internal combustion engine. According to this configuration, the purge concentration in the internal combustion engine is determined using the purge concentration stored in the second storage region in consideration of the delay until the purge gas located at the specific position reaches the internal combustion engine. be able to.

(Characteristic 7) In the fuel vapor processing apparatus of the present specification, the specific unit is disposed on the purge path closer to the canister than the control valve, and a pump for discharging the purge gas on the purge path to the control valve side; And a pressure sensor for detecting the pressure on the discharge side of the pump during driving. The specific position is a discharge port of the pump, and the specifying unit may specify the fuel vapor concentration at the specific position using the pressure detected by the pressure sensor. According to this configuration, when the negative pressure in the intake passage is small or positive, purge gas can be supplied to the intake passage using the pump. Further, since the density of the air in the purge gas and the evaporated fuel are different, the density of the purge gas changes when the purge concentration changes. When the density of the purge gas changes, the pressure of the purge gas delivered by the pump changes even if the pump is rotated at a constant rotational speed. For this reason, the density of the purge gas, that is, the purge concentration can be specified using the pressure difference between the purge gas on the suction side and the discharge side of the pump. According to the above evaporated fuel processing apparatus, the purge concentration at the specific position can be specified using the pump and the pressure sensor.

(Characteristic 8) In the evaporated fuel processing apparatus of the present specification, the specific position is located in the canister, and the specifying unit specifies the evaporated fuel concentration at the specific position using the desorption characteristic of the evaporated fuel in the canister. Good. When the evaporated fuel in the canister is supplied to the internal combustion engine, the amount of evaporated fuel in the canister decreases. The purge concentration changes according to the amount of evaporated fuel that desorbs from the canister and flows into the purge path. As a result, the purge concentration of the purge gas supplied from the canister changes according to the integrated flow rate of the purge gas since the vehicle was started. Therefore, the purge concentration can be specified using the desorption characteristic indicating the relationship between the purge concentration and the integrated flow rate of the purge gas.

(Characteristic 9) In the fuel vapor processing apparatus of the present specification, the determined position may be a position where the control valve is connected to the purge path located on the canister side.

(First embodiment)
The evaporated fuel processing apparatus 10 will be described with reference to the drawings. As shown in FIG. 1, the evaporated fuel processing apparatus 10 is mounted on a vehicle such as an automobile, and is disposed in a fuel supply system 2 that supplies fuel stored in a fuel tank FT to an engine EN.

  The fuel supply system 2 supplies fuel injected from a fuel pump (not shown) accommodated in the fuel tank FT to the injector IJ. The injector IJ has an electromagnetic valve whose opening degree is adjusted by an ECU (abbreviation of engine control unit) 100 described later. The injector IJ injects fuel into the engine EN.

  An intake pipe IP is connected to the engine EN via an intake manifold IM. The intake pipe IP is a pipe for supplying air to the engine EN by the negative pressure of the engine EN. An intake passage IW is configured by the intake pipe IP and the intake manifold IM. A throttle valve TV is disposed in the intake pipe IP. The throttle valve TV controls the amount of air flowing into the engine EN by adjusting the opening of the intake pipe IP. The throttle valve TV is controlled by the ECU 100.

  An air cleaner AC is disposed upstream of the throttle valve TV of the intake pipe IP. The air cleaner AC has a filter that removes foreign substances from the air flowing into the intake pipe IP. In the intake pipe IP, when the throttle valve TV is opened, the air passes through the air cleaner AC and is sucked into the engine EN. The engine EN burns fuel and air inside, and exhausts the exhaust pipe EP after combustion.

  The evaporated fuel processing apparatus 10 supplies the evaporated fuel in the fuel tank FT to the engine EN via the intake pipe IP. The evaporated fuel processing apparatus 10 includes a canister 14, a pump 12, a purge pipe 32, a control valve 34, a control unit 102 in the ECU 100, and a check valve 83. The canister 14 adsorbs the evaporated fuel generated in the fuel tank FT. The canister 14 includes activated carbon 14d and a case 14e that accommodates the activated carbon 14d. The case 14e has a tank port 14a, a purge port 14b, and an atmospheric port 14c. The tank port 14a is connected to the upper end of the fuel tank FT. As a result, the evaporated fuel in the fuel tank FT flows into the canister 14. The activated carbon 14d adsorbs evaporated fuel from the gas flowing from the fuel tank FT into the case 14e. Thereby, it is possible to prevent the evaporated fuel from being released into the atmosphere.

  The atmosphere port 14c communicates with the atmosphere via the air filter AF. The air filter AF removes foreign matter from the air flowing into the canister 14 through the atmospheric port 14c.

  A purge pipe 32 communicates with the purge port 14b. The purge pipe 32 is connected to an intake manifold IM between the throttle valve TV and the engine EN.

  A gas containing evaporated fuel in the canister 14 (hereinafter referred to as “purge gas”) flows into the purge pipe 32 from the canister 14 through the purge port 14b. The purge pipe 32 defines purge paths 22 and 24. The purge gas in the purge pipe 32 flows through the purge paths 22 and 24 and is supplied to the intake path IW.

  The pump 12 is disposed at an intermediate position of the purge pipe 32. A purge line 32 between the canister 14 and the pump 12 defines a purge path 22, and a purge line 32 between the pump 12 and the control valve 34 defines a purge path 24. The pump 12 is a so-called vortex pump (also called a cascade pump or a Wesco pump) or a centrifugal pump. The pump 12 is controlled by the control unit 102. The suction port 12 a of the pump 12 communicates with the canister 14 via the purge path 22.

  The discharge port 12 b of the pump 12 communicates with the purge pipe 32. The pump 12 delivers purge gas to the purge path 24. A check valve 83 is disposed at an intermediate position of the purge path 24. The check valve 83 allows the gas to flow through the purge path 24 toward the intake path IW, and prohibits the gas from flowing toward the canister 14. In the modified example, the evaporated fuel processing apparatus 10 may not include the check valve 83.

  A control valve 34 is disposed in the purge path 24 on the downstream side of the pump 12. When the control valve 34 is in a closed state, the purge gas in the purge path 24 is stopped by the control valve 34 and does not flow toward the intake path IW. On the other hand, when the control valve 34 is opened, the purge gas flows into the intake path IW. The control valve 34 is an electronic control valve and is controlled by the control unit 102.

  A pressure sensor 26 is disposed on the purge path 24. The pressure sensor 26 detects the pressure of the purge gas discharged from the pump 12. The purge path 22 on the upstream side of the pump 12 communicates with the canister 14. For this reason, the pressure in the purge path 22 is maintained at atmospheric pressure.

  The control unit 102 is a part of the ECU 100 and is disposed integrally with another part of the ECU 100 (for example, a part that controls the engine EN). Control unit 102 may be arranged separately from other parts of ECU 100. The control unit 102 includes a CPU and a memory 104 such as a ROM and a RAM. The control unit 102 controls the evaporated fuel processing apparatus 10 according to a program stored in the memory 104 in advance. Specifically, the control unit 102 outputs a signal to the pump 12 to control the pump 12. In addition, the control unit 102 outputs a signal to the control valve 34 to execute duty control. That is, the control unit 102 adjusts the valve opening time of the control valve 34 by adjusting the duty ratio of the signal output to the control valve 34.

  The ECU 100 is connected to an air-fuel ratio sensor 50 disposed in the exhaust pipe EP. The ECU 100 detects the air-fuel ratio in the exhaust pipe EP from the detection result of the air-fuel ratio sensor 50, and controls the fuel injection amount from the injector IJ.

  The ECU 100 is connected to an air flow meter 52 disposed near the air cleaner AC. The air flow meter 52 is a so-called hot wire type air flow meter, but may have other configurations. The ECU 100 receives a signal indicating the detection result from the air flow meter 52 and detects the amount of gas sucked into the engine EN.

  As shown in FIG. 2, the memory 104 has 300 storage areas 104a from No. 1 to No. 300 (in FIG. 2, only No. 1 and No. 2 are denoted by reference numerals). Each storage area 104a stores the evaporated fuel concentration (that is, the purge concentration) of the purge gas in each of the 300 partial paths 24a when the purge path 24 from the pump 12 to the control valve 34 is equally divided by 300. 300 partial paths 24a from the pump 12 side to the control valve 34 correspond to the first to 300th storage areas 104a in order from the pump 12 side.

  As shown in FIG. 3, the memory 104 further has 200 storage areas 104 b from No. 1 to No. 200 (in FIG. 3, only No. 1 and No. 2 are given symbols). Each storage region 104b has a purge path 24 from the control valve 34 to the engine EN (specifically, a combustion chamber of the engine EN), and 200 partial paths 24b when the intake pipe IP and the intake manifold IM are divided into 200 equal parts by volume. The purge concentration of each purge gas is stored. 200 partial paths 24b from the control valve 34 to the engine EN correspond to the first to 200th storage areas 104b in order from the pump 12 side. The division of the purge path 24 and the like is not limited to the volume, and may be divided on the basis of the length.

  The memory 104 further stores data maps 110 and 120 used in density determination processing described later. These data maps 110 and 120 will be clarified in the density determination process described later. Note that the data maps 130 and 140 shown in the memory 104 are data maps used in the second embodiment, and need not be stored in the memory 104 of the present embodiment.

  Next, a purge process for supplying the purge gas flowing out from the canister 14 to the intake path IW will be described. When the engine EN is being driven and the purge condition is satisfied, the control unit 102 performs a purge process by duty-controlling the control valve 34. The purge condition is a condition that is established when a purge process for supplying purge gas to the engine EN is to be executed, and is preset in the control unit 102 by the manufacturer according to the specific situation of the coolant temperature and purge concentration of the engine EN. It is a condition. The controller 102 constantly monitors whether the purge condition is satisfied while the engine EN is being driven. The control unit 102 controls the output of the pump 12 and the duty ratio of the control valve 34 based on the purge concentration. When the pump 12 is started, the purge gas adsorbed by the canister 14 and the air that has passed through the air filter AF are introduced into the engine EN. In the purge process, the control unit 102 controls the opening / closing of the control valve 34 based on the duty ratio. When the control valve 34 is opened, the purge gas is supplied from the canister 14 to the purge paths 22 and 24. The purge gas passes through the purge paths 22 and 24 and is supplied to the intake path IW. At this time, the control unit 102 controls to drive or stop the pump 12 in accordance with the state of the negative pressure in the intake path IW (for example, the rotational speed of the engine EN).

  While the purge process is being performed, the engine EN is supplied with the fuel supplied from the fuel tank FT via the injector IJ and the evaporated fuel by the purge process. The control unit 102 adjusts the injection time of the injector IJ and the duty ratio of the control valve 34 to adjust the air-fuel ratio of the engine EN to an optimal air-fuel ratio (for example, ideal air-fuel ratio). Therefore, it is desired that the control unit 102 appropriately grasps the amount of fuel supplied from the injector IJ to the engine EN and the amount of fuel supplied to the engine EN by the purge process. The fuel supplied from the injector IJ to the engine EN is determined by the opening degree of the injector IJ. On the other hand, the fuel supplied by the purge process varies depending on the purge concentration. For this reason, it is desired to appropriately determine the purge concentration of the purge gas supplied to the engine EN.

  When the ignition switch is turned on, the control unit 102 starts specifying the purge concentration. The control unit 102 specifies the purge concentration periodically (for example, every 16 ms) while the duty of the control valve 34 is controlled. Specifically, the control unit 102 drives the pump 12 at a predetermined rotation speed (for example, 10,000 rotations per minute), and detects the pressure of the purge gas delivered from the pump 12 by the pressure sensor 26. The pressure of the purge gas varies depending on the purge concentration. This is because the purge gas is boosted by the pump 12 as the density of the evaporated fuel is lower than the density of air and the amount of evaporated fuel in the purge gas is large (that is, the purge concentration is high).

  The control unit 102 specifies how much the purge gas has been boosted by the pump 12, that is, the pressure difference between the purge gas before and after the pump 12. That is, the atmospheric pressure (predetermined value or a value detected by the atmospheric pressure sensor mounted on the vehicle) is subtracted from the pressure detected by the pressure sensor 26. The memory 104 stores a data map indicating the relationship between the purge gas pressure difference and the purge concentration prepared in advance by experiments. The control unit 102 specifies the purge concentration using the specified pressure difference and the data map. Thereby, the purge concentration in the discharge port 12b of the pump 12 is specified. The specified purge concentration is stored in an area of the memory 104 different from the storage areas 104a and 104b. The pressure sensor 26 may be a sensor that detects a pressure difference before and after the pump 12.

  The control unit 102 executes the concentration determination process shown in FIGS. 4 and 5 independently of specifying the purge concentration. The density determination process includes two processes of an upstream determination process and a downstream determination process shown in FIG. In the upstream determination process, the purge concentration in the control valve 34 is determined. On the other hand, in the downstream determination process, the purge concentration in the engine EN is determined.

  The density determination process starts when the ignition switch is turned on, and is repeatedly executed periodically (for example, every 16 ms) until the ignition switch is switched from on to off. At the timing when the density determination process is executed, a default value (for example, 0) is stored in the storage areas 104 a and 104 b of the memory 104. That is, the contents in the storage areas 104a and 104b are replaced with default values when the ignition switch is switched from on to off.

  In the upstream determination process, first, in S12, the control unit 102 determines whether or not the purge concentration has been specified after the ignition switch is turned on. If the purge concentration is not specified (NO in S12), the upstream determination process is terminated. On the other hand, when the purge concentration is specified (YES in S12), in S14, the control unit 102 determines whether or not a default value is stored in all the storage areas 104a. When the default value is stored in all the storage areas 104a (YES in S14), in S16, the control unit 102 determines the latest specified purge concentration (hereinafter referred to as “latest concentration”) in S16. The data is stored in all the storage areas 104a, and the process proceeds to S18. On the other hand, if a value other than the default value is stored in any of the storage areas 104a (NO in S14), S16 is skipped and the process proceeds to S18.

  Next, in S18, the control unit 102 determines whether or not a purge process is being performed. Specifically, it is determined whether or not the control unit 102 is controlling the control valve 34. If the control valve 34 is not controlled, it is determined that the purge process is not being executed (NO in S18), and the upstream determination process is terminated. When the purge process is not continuously executed for a predetermined period (for example, 5 seconds) or longer, the control unit 102 purges the purge concentration stored in the first to 299th storage areas 104a every predetermined period. Is replaced with the purge concentration in the second to 300th storage areas 104a, and the latest concentration is stored in the first storage area 104a. In this configuration, the purge process is not executed for a long period of time, and the purge gas in the purge path 22 is diffused and stored in the storage area 104a according to the state in which the purge concentration in the purge path 22 approaches uniformly. The purge concentration can be changed. If the purge process is not executed, the stored contents of the storage area 104a may be maintained without being changed.

  When the control valve 34 is controlled, it is determined that the purge process is being executed (YES in S18), and the processes of S20 to S24 are executed. In the processing of S20 to S24, the purge concentration stored in the storage area 104a is shifted in accordance with the flow rate of the purge gas in the purge path 22 per unit time. In S20, the control unit 102 specifies the storage area 104a to which the purge concentration stored in the first storage area 104a is moved (hereinafter referred to as “shift number”).

As shown in FIG. 1, the memory 104 stores a data map 110 in which the purge flow rate per second and the shift number are associated with each other. The data map 110 is calculated in advance and stored in the memory 104. The data map 110 is calculated and created based on the following. That is, it is assumed that the purge path 24 has an area of 16πmm ² (that is, a diameter of 8.0 mm), a length of 1000 mm, 300 storage areas 104a, and an upstream determination process execution period of 16 ms. In this case, one storage area 104a corresponds to the length of 3.33 mm (≈1000 mm / 300) of the purge path 24 and corresponds to a volume of 3.33 mm × 16πmm ² ≈167.3 mm ³ . Therefore, purge flow ^rate, if it is 167.3mm 3 /16ms≒0.01 liters / sec, each time the upstream side determination process is executed (i.e., every 16 ms), the number # 1 ～299 storage area 104a of the When the purge concentration is stored in place of the purge concentration stored in the second to 300th storage areas 104a (that is, the shift number = 1), the purge of the storage area 104a is performed in accordance with the purge gas flow. The density can be shifted.

  In S20, the control unit 102 estimates the purge flow rate of the purge path 24. Specifically, the control unit 102 estimates based on the pressure (negative pressure) of the intake manifold IM that correlates with the purge flow rate of the purge path 24 and the duty ratio of the control valve 34. The pressure of intake manifold IM correlates with the intake air amount detected by air flow meter 52 and the opening of throttle valve TV. In the modified example, a pressure sensor that detects the pressure of the intake manifold IM may be arranged to directly detect the pressure of the intake manifold IM. The control unit 102 includes a first data map indicating the correlation between the intake air amount detected by the air flow meter 52, the opening degree of the throttle valve TV, and the pressure of the intake manifold IM, the purge flow rate of the purge path 24, and the intake manifold IM. And a second data map showing a correlation between the pressure (negative pressure) and the duty ratio of the control valve 34 is stored. These data maps are specified in advance by experiments and stored in the memory 104. The control unit 102 specifies the pressure of the intake manifold IM using the intake air amount detected by the air flow meter 52, the opening degree of the throttle valve TV, and the first data map. Next, the control unit 102 estimates the purge flow rate of the purge path 24 from the specified pressure of the intake manifold IM, the duty ratio of the control valve 34, and the second data map.

  Next, the control unit 102 specifies the number of shifts (hereinafter referred to as “300−M” (an integer of 1 ≦ M ≦ 300)) using the estimated purge flow rate and the data map 110. In subsequent S22, the control unit 102 replaces the purge concentration stored in the 1st to Mth storage areas 104a with the 300th to 300-M + 1th storage areas 104a and stores them. Thereby, the purge concentration in the control valve 34 stored in the 300th storage area 104a is determined. Next, in S24, the control unit 102 replaces and stores the latest concentration with the storage area 104a from No. 1 to 300-M to No. 1, and ends the upstream determination process.

  In the evaporated fuel processing apparatus 10, the purge concentration at the discharge port 12 b of the pump 12 is specified using the pressure sensor 26. Since it takes time until the purge gas with the specified purge concentration reaches the control valve 34, the purge gas with the purge concentration specified with the pressure sensor 26 and the purge gas supplied from the control valve 34 to the intake path IW In some cases, the purge concentration may be different. In the upstream determination process, the purge concentration in the control valve 34 is changed as the purge gas flows through the purge path 24.

  As shown in FIG. 6, when the purge flow rate is relatively small as 0.01 liter / second and the shift number = 300−M = 1 (ie, M = 299) is specified in S20, the processing in S22 and S24 is performed. , Each of the concentrations α1 to α299 stored in the storage region 104a from No. 1 to 299 is replaced with each of the concentrations α2 to α300 stored in the storage region 104a from No. 2 to 300. . Then, the latest density β is stored in the first storage area 104a.

  On the other hand, as shown in FIG. 7, when the purge flow rate is relatively large at 1.0 liter / second and the shift number is specified as S = 300−M = 100 (ie, M = 200) in S20, S22, S24 In this process, the densities α1 to α200 stored in the first to 200th storage areas 104a are replaced with the densities α101 to α300 stored in the 101th to 300th storage areas 104a, respectively. Store. Then, the latest density β is stored in the first to 100th storage areas 104a.

  According to this configuration, the purge concentration of the control valve 34 can be changed in accordance with the flow rate of the purge gas flowing through the purge path 24. Thereby, the purge concentration in the control valve 34 can be determined more accurately.

  Next, the downstream determination process will be described with reference to FIG. The downstream determination process is executed following the upstream determination process. In the downstream determination process, first, in S52, the control unit 102 determines whether or not a default value is stored in all the storage areas 104b as in S14. When the default values are stored in all the storage areas 104b (YES in S52), in S54, the control unit 102 sets the purge concentration stored in the 300th storage area 104a to all the storage areas 104b. Then, the process proceeds to S56. On the other hand, if a value other than the default value is stored in any of the storage areas 104b (NO in S52), S54 is skipped and the process proceeds to S56.

  Next, in S56, as in S18, the control unit 102 determines whether or not a purge process is being performed. If the purge process is not executed (NO in S56), the downstream determination process is terminated. On the other hand, when the purge process is being executed (YES in S56), the processes of S58 to S62 are executed. In the processing of S58 to S62, the purge concentration stored in the storage area 104b is shifted in accordance with the flow rate per unit time of intake air from the control valve 34 to the engine EN. In S58, as in S20, the control unit 102 specifies to which storage area 104b the purge concentration stored in the first storage area 104b is moved (hereinafter referred to as “shift number”). .

As shown in FIG. 1, the memory 104 stores a data map 120 in which the intake amount per second and the shift number are associated with each other. The data map 120 is calculated in advance and stored in the memory 104. The data map 120 is calculated and created based on the following. A purge path 24 and an intake manifold IM are included from the control valve 34 to the engine EN. Assume that the total volume of these paths from the control valve 34 to the engine EN is 1250000πmm ³ , the number of storage areas 104b is 200, and the execution cycle of the downstream determination process is 16 ms. In this case, one storage area 104b corresponds to 250,000πmm ³ / 200≈19620 mm ³ . Therefore, if the purge flow rate is 19620mm ³ /16ms≒1.23 liters / sec, each time the downstream determining process is executed (i.e., every 16 ms), the purge concentration storage area 104b of the No. 1 No. 199 By substituting with the purge concentration of the second to 200th storage areas 104b (that is, the shift number = 1), the purge concentration of the storage areas 104b can be shifted in accordance with the flow of the purge gas.

  In S58, the control unit 102 estimates the intake air amount of the engine EN (specifically, the combustion chamber). Specifically, the control unit 102 calculates the sum of the intake air amount detected by the air flow meter 52, that is, the air amount introduced from the atmosphere, and the purge flow rate supplied to the intake path IW by the purge process. . The purge flow rate is estimated from the pressure (negative pressure) of the intake manifold IM and the duty ratio of the control valve 34 as in S20.

  Next, the control unit 102 specifies the number of shifts (hereinafter referred to as “200−Y” (an integer of 1 ≦ Y ≦ 200)) using the estimated intake air amount and the data map 120. In subsequent S60, the control unit 102 replaces the purge concentration stored in the 1st to Yth storage areas 104b with the purge concentration stored in the 200th to 200-Y + 1th storage areas 104b. Next, in S62, the control unit 102 stores the purge concentration stored in the 300th storage area 104a in the 200th-Yth storage area 104b and ends the downstream determination process.

  When determining the fuel injection amount of the injector IJ, the control unit 102 determines the purge concentration stored in No. 200 as the purge concentration of the purge gas supplied to the engine EN.

  As shown in FIG. 8, when it is specified in S58 that the number of shifts = 200−Y = 100 (that is, Y = 100), in the processes of S60 and S62, they are stored in the storage areas 104b from No. 1 to No. 100. Each of the densities γ1 to γ100 is replaced with each of the densities γ101 to γ200 stored in the storage area 104b from the 101st to the 200th. Then, the latest density δ is stored in the storage area 104a from No. 101 to No. 200.

  According to this configuration, the purge concentration in the engine EN can be changed in accordance with the flow rate of the purge gas flowing from the control valve 34 to the engine EN. Thereby, the purge concentration in the engine EN can be determined more accurately.

(Second embodiment)
In the second embodiment, the density determination process executed by the control unit 102 is different. The memory 104 has 313 storage areas 204a as in the first embodiment, but does not correspond to the purge path 22. Similarly, the memory has 243 storage areas 204b, but does not correspond to the section from the control valve 34 to the engine EN.

  As shown in FIG. 9, the control unit 102 sets the purge concentrations α1 to α312 stored in the storage areas 204a from No. 1 to 312 to Nos. 2 to 313 each time the purge concentration is periodically specified. The purge concentrations α2 to α313 stored in the number storage area 204a are replaced and stored. Then, the latest density β is stored in the first storage area 204a. As shown in FIG. 10, the control unit 102 similarly calculates each of the purge concentrations γ1 to γ242 stored in the storage areas 204b from No. 1 to No. 242 every time the purge concentration in the control valve 34 is calculated. The purge concentrations γ2 to γ243 stored in the second to 243rd storage areas 204b are replaced and stored. Then, in the upstream determination process described later, the purge concentration δ (that is, the purge concentration most recently determined in S74 of FIG. 11) in the control valve 34 determined last is stored in the first storage area 204b.

  As shown in FIG. 11, in the upstream determination process, first, the processes of S12 to S18 similar to those in FIG. 4 are executed. If YES in S18, the processes of S72 and S74 are executed. In the processes of S72 and S74, the purge concentration in the control valve 34 is determined using the purge concentration stored in the storage region 204a in accordance with the flow of the purge gas in the purge path 22 per unit time. In S72, the control unit 102 stores the number of storage areas 204a in order to determine the purge concentration in the control valve 34 among the purge concentrations stored in the first to 313th storage areas 204a. Specify whether to use the purge concentration.

  As shown in FIG. 1, the memory 104 stores a data map 130 in which a purge flow rate per second, a number, and a coefficient are associated with each other. The data map 130 is calculated in advance and stored in the memory 104. The data map 130 is calculated and created as follows. That is, if the purge passage 22 has a volume of about 0.05 liter, and the minimum value of the purge flow rate is 0.01 liter / second, the purge gas is supplied from the pump 12 to the control valve with the minimum purge flow rate. It takes 5000 ms to flow to 34. Assuming that the execution cycle of the upstream side determination process is 16 ms, 5000 ms / 16 ms = 313 storage areas 204a are prepared, and when the purge flow rate is 0.01 liter / second, the No. 313 storage area 204a is selected. Has been created to be. The coefficient is used when calculating the purge concentration in S74 described later.

  In S72, the control unit 102 estimates the purge flow rate of the purge path 22 as in S20. Next, the control unit 102 specifies the number and coefficient of the storage area 204 a using the estimated purge flow rate and the data map 130. Next, in S74, the control unit 102 calculates the purge concentration in the control valve 34. Specifically, the control unit 102 determines the purge concentration calculated in the previous S74 (default value (for example, “0” when there is no calculated purge concentration)) (hereinafter referred to as “previous concentration”), and S72. The previous concentration + (specific concentration−previous concentration) / coefficient is calculated by using the purge concentration (hereinafter referred to as “specific concentration”) and the coefficient stored in the storage area 204a of the number specified in (1). Thus, the purge concentration in the control valve 34 is calculated.

  Also with this configuration, the purge concentration of the control valve 34 can be changed in accordance with the flow rate of the purge gas flowing through the purge path 22. Thereby, the purge concentration in the control valve 34 can be determined more accurately.

  Next, the downstream determination process will be described with reference to FIG. The downstream determination process is executed following the upstream determination process. In the downstream determination process, first, a process similar to S52 of FIG. 5 is executed. When the default value is not stored in all the storage areas 204b (YES in S52), in S80, the control unit 102 finally stores the purge concentration determined in S74 of the upstream determination process in all the storage areas 204b. Store. Next, processing similar to S56 in FIG. 5 is executed. When the purge process is being executed (YES in S56), the processes of S82 and S84 are executed. In the processing of S82, the control unit 102 determines the number of purge concentrations stored in the storage area 204b from No. 1 to No. 243 in accordance with the flow rate per unit time of intake air from the control valve 34 to the engine EN. It is specified whether to use the purge concentration stored in the storage area 204b.

  As shown in FIG. 1, the memory 104 further stores a data map 140 in which an intake amount per second, a number, and a coefficient are associated with each other. The data map 140 is calculated in advance and stored in the memory 104. The data map 140 is calculated and created in the same manner as the data map 130. That is, when the volume of the path from the control valve 34 to the engine EN is 3.9 liters and the minimum value of the intake air amount is 1.0 liter / second, the purge gas is discharged from the control valve 34 to the engine EN with the minimum intake air amount. It takes 3900 ms to flow up to. Assuming that the execution cycle of the downstream side determination process is 16 ms, 3900 ms / 16 ms = 243 storage areas 204b are prepared, and when the intake amount is 1.0 liter / second, the 243rd storage area 204b is selected. Has been created to be.

  In S82, the control unit 102 estimates the intake air amount as in S58. Next, the control unit 102 specifies the number and coefficient of the storage area 204b using the estimated intake air amount and the data maps 150 and 160. Next, in S84, the control unit 102 calculates the purge concentration in the engine EN. Specifically, the control unit 102 determines the purge concentration calculated in the previous S84 (default value (eg, “0” when there is no calculated purge concentration)) (hereinafter referred to as “previous engine concentration”), Using the purge concentration (hereinafter referred to as “specific engine concentration”) stored in the storage area 204b of the number specified in S82 and a coefficient, the previous engine concentration + (specific engine concentration−previous engine concentration). The purge concentration in the engine EN is calculated by calculating the coefficient.

  Also with this configuration, the purge concentration in the engine EN can be changed in accordance with the amount of intake air flowing from the control valve 34 to the engine EN. Thereby, the purge concentration in the engine EN can be determined more accurately.

(Third embodiment)
Differences from the first and second embodiments will be described. The evaporated fuel processing apparatus 10 of the third embodiment does not include the pressure sensor 26. The control unit 102 specifies the purge concentration using the desorption characteristic of the canister 14 when the evaporated fuel once adsorbed by the canister 14 is desorbed. Specifically, a characteristic graph representing the desorption characteristics of the canister 14 shown in FIG. 13 is stored in advance in the memory 104. This graph is specified in advance by experiments.

  In the characteristic graph, the horizontal axis indicates the integrated purge flow rate, and the vertical axis indicates the purge concentration. The integrated purge flow rate is an integrated value of the purge flow rate from the timing when the ignition switch is switched from OFF to ON. A solid line 300 shows the desorption characteristics specified in the experiment. The canister 14 has a desorption characteristic such that the purge concentration decreases as the integrated purge flow rate increases.

  The control unit 102 corrects the desorption characteristics of the canister 14 according to the actual canister 14. The desorption characteristics of the canister 14 vary depending on the period of use, temperature, and individual difference of the canister 14. The controller 102 corrects the desorption characteristics of the canister 14 in order to take into account such fluctuations. Specifically, the correction process shown in FIG. 14 is executed. The correction process is repeatedly executed when the ignition is switched from off to on.

  In the correction process, first, in S102, the control unit 102 determines whether or not the desorption characteristic has already been corrected. Specifically, it is determined whether or not a correction completion flag set in S110 described later has already been set. When the correction completion flag is set, it is determined that the correction has been executed (YES in S102), and the correction process is terminated. On the other hand, when the correction completion flag is not set, it is determined that the correction is not executed (NO in S102), and the process proceeds to S104.

  In S104, as in S18 of FIG. 4, the control unit 102 determines whether or not a purge process is being performed. If the purge process has not been executed (NO in S104), the correction process is terminated. On the other hand, when the purge process is being executed (YES in S104), in S106, the control unit 102 determines the correction value P based on the deviation of the air-fuel ratio due to the purge process. Specifically, when the purge process is started, the evaporated fuel is supplied from the evaporated fuel processing apparatus 10 to the engine EN in addition to the injected fuel from the injector IJ. For this reason, the air-fuel ratio shifts from the reference air-fuel ratio (for example, the ideal air-fuel ratio) to the rich side. The ECU 100 reduces the amount of fuel injected from the injector IJ in order to suppress the deviation of the air-fuel ratio so that the air-fuel ratio becomes the reference air-fuel ratio. The control unit 102 corrects the desorption characteristic (that is, the solid line 300) of the canister 14 shown in FIG. The amount of purge concentration deviation at flow rate = 0 is determined.

  Next, in S108, the control unit 102 corrects the desorption characteristics of the canister 14. Specifically, the control unit 102 shifts the solid line 300 by the overall correction value P. Next, in S110, the control unit 102 sets a correction completion flag in the memory 104, and ends the correction process.

  Next, referring to FIG. 15, a purge concentration specifying process is executed. When the ignition switch is turned on, the control unit 102 periodically executes a purge concentration specifying process. First, in S122, as in S18 of FIG. 4, the control unit 102 determines whether or not a purge process is being performed. If the purge process has not been executed (NO in S122), the purge concentration specifying process is terminated. On the other hand, when the purge process is being executed (YES in S122), in S124, the control unit 102 determines whether or not the correction completion flag is set. If the correction completion flag is not set (NO in 124), the purge concentration specifying process is terminated. According to this configuration, it is possible to avoid specifying the purge concentration using the desorption characteristics of the canister 14 before correction. For example, the purge process is not executed at the timing when the correction process is executed (NO in S104 in FIG. 13), while the purge process is executed at the timing when the purge concentration specifying process is executed. By using the desorption characteristic of the canister 14 before correction, the purge concentration is specified, and it is possible to avoid the purge concentration being significantly different from the actual purge concentration.

  Next, in S126, the control unit 102 specifies the purge concentration using the corrected desorption characteristic and the integrated purge flow rate, and executes the purge concentration specifying process. The control unit 102 calculates the integrated purge flow rate by integrating the purge flow rate per unit time described above.

  The control unit 102 executes the concentration determination process of FIG. 4 and FIG. 5 or FIG. 11 and FIG. 12 using the purge concentration specified by the purge concentration specifying process. At this time, the storage areas 104a and 204a are 300 storage areas corresponding to 300 sections from the purge port 14b of the canister 14 to the control valve 34.

  According to this configuration, the purge concentration can be specified without arranging the pressure sensor 26.

  As mentioned above, although embodiment of this invention was described in detail, these are only illustrations and do not limit a claim. The technology described in the claims includes various modifications and changes of the specific examples illustrated above.

(1) In each of the above embodiments, the supercharger is not disposed in the intake pipe IP. However, the technique described in this specification can also be used for a vehicle in which a supercharger is arranged in the intake pipe IP. In this case, the storage area corresponding to the path from the control valve 34 to the engine EN is the storage area corresponding to the path passing through the supercharger, and the path not passing through the supercharger (that is, the path of each of the above embodiments). And a storage area corresponding to. The control unit 102 is used for the downstream determination process depending on whether the purge gas is supplied to the engine EN through the supercharger or whether the purge gas is supplied to the engine EN without passing through the supercharger. The storage area may be changed. Alternatively, the path from the control valve 34 to the engine EN may be a path that passes through the supercharger.

(2) The combination of the upstream determination process and the downstream determination process of the concentration determination process in each of the above embodiments is not limited to the above embodiment. For example, the control unit 102 may execute the process of FIG. 4 as the upstream determination process and execute the process of FIG. 12 as the downstream determination process. Similarly, for example, the control unit 102 may execute the process of FIG. 11 as the upstream determination process and execute the process of FIG. 5 as the downstream determination process. Furthermore, the control unit 102 does not have to execute the downstream determination process while executing the upstream determination process as the density determination process. In this case, the control unit 102 may determine the purge concentration stored in the storage areas 104a and 204a corresponding to the control valve 34 as the purge concentration of the purge gas supplied to the engine EN. This configuration is particularly useful in a situation where the distance from the control valve 34 to the engine EN is short and an error can be allowed without considering the delay from the control valve 34 to the engine EN.

(3) The method for specifying the purge concentration is not limited to the combination of the pump 12 and the pressure sensor 26 described above, or the method using the desorption characteristic of the canister 14. For example, a venturi pipe and a pressure sensor may be disposed in the purge path 24, and the purge concentration (purge gas density) may be specified based on the pressure change of the purge gas passing through the venturi pipe.

(4) In the upstream determination process of the first embodiment, when the shift number is determined (S20 in FIG. 4) and the purge concentration is replaced (S22 in FIG. 4), it is specified by the pressure sensor 26 and the pump 12. The purge concentration is stored in the storage area 104a as it is. However, for example, in the storage area 104a, the purge concentration specified in the first storage area 104a is stored as it is, and in the 300-M through the second storage area 104a, the 300-M + 1 through the first storage are stored. The purge concentration specified so as to gradually change (for example, linearly change) to the region 104a may be corrected and stored.

(5) The storage area 204a and the storage area 204b of the second embodiment may be continuously arranged. That is, the memory 104 may have storage areas 204a from 313 to 555 instead of the storage areas 204b from 1 to 243. In the downstream determination process, the control unit 102 may execute the process using the purge concentration stored in the storage areas 204a to 555 in place of the storage areas 204b from 1 to 243. . In the present modification, the storage areas 204a from No. 313 to No. 555 are examples of “second storage areas”.

(6) In the first embodiment described above, the shift number is specified based on the intake air amount of the engine EN in S58 of the downstream side determination process shown in FIG. However, the control unit 102 may specify the shift number based on the rotation speed of the engine EN. Specifically, instead of the data map 120, the memory 104 may store a data map in which the rotation speed and the shift number of the engine EN are associated with each other. This data map may be specified and stored in advance by experiments.

(7) In the second embodiment, the number and coefficient of the storage area 204b are specified based on the intake amount of the engine EN in S82 of the downstream side determination process shown in FIG. However, the control unit 102 may specify the number and coefficient of the storage area 204b based on the rotational speed of the engine EN. Specifically, instead of the data map 140, the memory 104 may store a data map in which the engine speed, number, and coefficient are associated with each other. This data map may be specified and stored in advance by experiments.

  The technical elements described in this specification or the drawings exhibit technical usefulness alone or in various combinations, and are not limited to the combinations described in the claims at the time of filing. In addition, the technology illustrated in the present specification or the drawings achieves a plurality of objects at the same time, and has technical utility by achieving one of the objects.

2: Fuel supply system 10: Evaporative fuel processing device 12: Pump 12b: Discharge port 14: Canister 14a: Tank port 14b: Purge port 14c: Atmospheric ports 22, 24: Purge path 26: Pressure sensor 34: Control valve 100: ECU
102: Control unit 104: Memory 104a: Storage area 104b: Storage area EN: Engine FT: Fuel tank IJ: Injector IM: Intake manifold IP: Intake pipe IW: Intake path TV: Throttle valve

Claims (11)

An evaporative fuel processing device mounted on a vehicle,
A canister that adsorbs the evaporated fuel in the fuel tank;
Arranged on the purge path that connects the intake path of the internal combustion engine and the canister, the communication state that communicates the canister and the intake path via the purge path, and the cutoff that blocks the canister and the intake path on the purge path A control valve that switches to a state,
A specific unit that repeatedly specifies the fuel vapor concentration of the purge gas at a specific position from the canister to the control valve;
A determining unit that determines the evaporated fuel concentration at a determined position that is located closer to the internal combustion engine than the specified position using the evaporated fuel concentration that has been specified at the specified position;
The decision part
A memory having first storage areas of L from 1 to L (L is an integer of 2 or more);
A memory control unit,
The memory controller
A path through which purge gas flows between the specific position and the determined position in the Kth first storage area (K is an integer of 1 ≦ K ≦ L) among the L first storage areas is determined from the specific position. The vaporized fuel concentration of the purge gas located in the Kth section when the above is divided into L sections from No. 1 to L in order,
When the purge gas flows in the path between the specific position and the determined position, it is stored in the first storage area from No. M (M is an integer of 1 ≦ M ≦ L) to No. 1 in accordance with the flow of the purge gas. The evaporated fuel concentration is moved from L number to LM + 1, and the value obtained by using the evaporated fuel concentration last specified by the specifying unit in the first storage area from LM number to No. 1 Store
The determining unit determines an evaporated fuel concentration stored in an Lth first storage area as an evaporated fuel concentration at a determination position.   The evaporative fuel processing apparatus according to claim 1, wherein the memory control unit stores the evaporative fuel concentration specified last by the specifying unit in the first storage area from the LM number to the first number. The memory further includes X storages Nos. 1 to X (where X is an integer equal to or greater than 2),
The memory controller
A path through which purge gas flows between the determined position and the internal combustion engine in the second W storage area (W is an integer of 1 ≦ W ≦ X) of the X second storage areas is determined from the determined position to the internal combustion engine. Stores the evaporated fuel concentration of the purge gas located in the W-th section when the above is divided into X sections from the first to the X-th in order,
When the purge gas flows in the path between the determined position and the internal combustion engine, it is stored in the second storage area from No. Y (Y is an integer equal to or less than X) to No. 1 in accordance with the flow of the purge gas. The evaporation fuel concentration is moved from X to XY + 1, and the evaporation fuel specified at the timing of moving the evaporation fuel concentration from X to XY + 1 is transferred to the second storage area from XY to 1. Store the value obtained using the fuel concentration,
The evaporative fuel processing apparatus according to claim 1 or 2, wherein the determination unit determines the evaporative fuel concentration stored in the Xth second storage area as the evaporative fuel concentration in the internal combustion engine.   The memory control unit stores the evaporated fuel concentration stored in the Lth first storage region at the timing of moving the evaporated fuel concentration from the Xth to the XY + 1th in the XYth to the first second storage region. The evaporative fuel processing apparatus of Claim 3 which stores. An evaporative fuel processing device mounted on a vehicle,
A canister that adsorbs the evaporated fuel in the fuel tank;
Arranged on the purge path that connects the intake path of the internal combustion engine and the canister, the communication state that communicates the canister and the intake path via the purge path, and the cutoff that blocks the canister and the intake path on the purge path A control valve that switches to a state,
A specific unit that repeatedly specifies the fuel vapor concentration of the purge gas at a specific position from the canister to the control valve;
A determining unit that determines the evaporated fuel concentration at a determined position that is located closer to the internal combustion engine than the specified position using the evaporated fuel concentration that has been specified at the specified position;
The decision part
A memory having first storage areas from B to B (B is an integer of 2 or more);
A memory control unit,
The memory control unit moves the evaporated fuel concentration stored in the first storage area from No. 1 to B-1 to the first storage area from No. 2 to B every time the evaporated fuel concentration is specified. , Storing the specified evaporated fuel concentration in the first storage area No. 1;
When the purge gas flows in the path between the specific position and the determined position, the determining unit determines the concentration of the evaporated fuel stored in the first storage area from No. 1 to No. B in accordance with the flow of the purge gas. Among these, the evaporated fuel concentration stored in the first storage area of No. C (1 ≦ C ≦ B) and the evaporated fuel concentration at the determined position determined last time are used to determine the evaporated fuel concentration at the determined position. Determine the evaporative fuel processing device.   The evaporative fuel processing apparatus according to claim 5, wherein the determination unit further determines a fuel vapor concentration at the determination position using a coefficient determined in accordance with the flow of the purge gas.   The determination unit subtracts the evaporated fuel concentration at the previously determined position from the evaporated fuel concentration stored in the first storage area of No. C by the coefficient by subtracting the evaporated fuel concentration at the previously determined determined position from the evaporated fuel concentration at the previously determined position. The evaporated fuel processing apparatus according to claim 6, wherein the evaporated fuel concentration at the determination position is determined by adding the divided values. The memory further includes D storages Nos. 1 to D (D is an integer of 2 or more),
Whenever the fuel vapor concentration at the determined position is determined, the memory control unit changes the fuel vapor concentration stored in the second storage area from No. 1 to D-1 to the second storage area from No. 2 to D. And the evaporated fuel concentration at the determined position is stored in the second storage area of No. 1,
When the purge gas flows in the path of the internal combustion engine from the determined position, the determining unit determines that E of the evaporated fuel concentration stored in the second storage area from No. 1 to D corresponds to the flow of the purge gas. The evaporated fuel concentration in the internal combustion engine is determined using the evaporated fuel concentration stored in the second storage area of the number (an integer of 1 ≦ E ≦ D) and the evaporated fuel concentration in the previously determined internal combustion engine. The evaporative fuel processing apparatus as described in any one of Claim 5 to 7. The specific part
A pump that is disposed on the purge path on the canister side of the control valve, and that discharges purge gas on the purge path to the control valve side;
A pressure sensor for detecting the pressure on the discharge side of the pump during driving of the pump,
The specific position is the pump outlet,
The evaporative fuel processing apparatus according to any one of claims 1 to 8, wherein the specifying unit specifies an evaporative fuel concentration at a specific position using the pressure detected by the pressure sensor. The specific location is located in the canister
The evaporative fuel processing apparatus according to any one of claims 1 to 8, wherein the specifying unit specifies an evaporative fuel concentration at a specific position using a desorption characteristic of the evaporative fuel of the canister.   The evaporative fuel processing apparatus according to any one of claims 1 to 10, wherein the determined position is a position where the control valve and a purge path located on the canister side are connected.

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