JP2018013111A - Evaporated fuel treatment device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a technology for determining an amount of purge gas supplied to an internal combustion engine while considering delay between timing of specifying a flow rate of the purge gas and timing of arrival of the purge gas specified in flow rate at the internal combustion engine.SOLUTION: In an evaporated fuel treatment device, amounts of purge gas positioned respectively in sections obtained by dividing a flow channel in which the purge gas flows between a control valve 34 and an engine EN into 300 sections of 1st to 300th from the control valve 34 to the engine EN, are stored in 300 storage regions 104a from 1st to 300th. The amounts of purge gas stored in Mth to 1st storage regions are moved from 300th to 300-M+1th according to an intake amount of an internal combustion engine, and the amount of purge gas specified last by a specifying portion, is stored in the storage regions of 300-Mth to 1st. By using the amount of purge gas stored in a first storage region of 300th, an amount of purge gas to be taken into the internal combustion engine is estimated.SELECTED DRAWING: Figure 3

Description

  The present specification discloses an evaporative fuel processing device that supplies evaporative fuel generated in a fuel tank to an internal combustion engine through 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. Hereinafter, the process in which the purge gas passes through the control valve and is supplied to the internal combustion engine is referred to as a purge process.

  During the purge process, the air-fuel ratio of the internal combustion engine changes depending on the amount of evaporated fuel supplied 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 amount of evaporated fuel supplied to the internal combustion engine. If the flow rate of the purge gas supplied to the internal combustion engine can be specified, the evaporated fuel amount can be specified by multiplying the purge gas flow rate by the evaporated fuel concentration of the purge gas (hereinafter referred to as “purge concentration”). . The flow rate of the purge gas passing through the control valve can be specified by using the opening degree of the control valve and the pressure in the intake path (pressure difference before and after the control valve).

  However, as disclosed in Patent Document 1, when a supercharger is mounted in the intake path, the purge path is connected to the intake path upstream from the supercharger, that is, at a position away from the internal combustion engine. Is done. This is because, while the supercharger is operating, the pressure downstream from the supercharger is positive, so in the configuration where the purge path is connected downstream from the supercharger, the purge path is changed to the intake path. This is because it is difficult to supply the purge gas appropriately.

JP 2007-278094 A

  In the configuration in which the purge path is connected to the intake path upstream of the supercharger, the distance from the control valve to the internal combustion engine is long. Therefore, the timing for specifying the flow rate of purge gas passing through the control valve (hereinafter referred to as “purge gas amount”) and the timing for supplying the purge gas at that flow rate to the internal combustion engine are greatly different. For example, the purge gas amount passing through the control valve specified at the first timing is different from the purge gas amount supplied to the internal combustion engine at the first timing, and the purge gas passing through the control valve at the first timing is It reaches the internal combustion engine at a later second timing.

  This specification describes a technique for determining the amount of purge gas supplied to an internal combustion engine in consideration of a delay between the timing at which the flow rate of the purge gas is specified and the timing at which the purge gas having the specified flow rate arrives at the internal combustion engine. provide.

  The technology disclosed in the present specification relates to a fuel vapor processing apparatus mounted on a vehicle. The evaporative fuel processing device is a canister that adsorbs evaporative fuel in a fuel tank and a purge path that connects an intake path and a canister of an internal combustion engine, and is more than a throttle valve and a supercharger disposed on the intake path. Arranged on the purge path connected to the upstream intake path, a communication state in which the canister and the intake path communicate with each other via the purge path, and a cutoff state in which the canister and the intake path are blocked on the purge path; The amount of purge gas in the gas sucked into the internal combustion engine is estimated by using the control valve that switches to, the specific part that repeatedly specifies the amount of purge gas that passes through the control valve per unit time, and the purge gas amount that has already been specified by the specific part An estimation unit. The estimation unit includes a memory having L storage areas from 1 to L (L is an integer equal to or greater than 2), and a memory control unit. The memory control unit provides a flow path through which purge gas flows between the control valve and the internal combustion engine in the Kth storage area (K is an integer of 1 ≦ K ≦ L) among the L storage areas. The purge gas amount located in the No. K section when the internal combustion engine is divided into L sections from No. 1 to No. L in order is stored, and the No. M (M is 1 ≦ 1) according to the intake air amount of the internal combustion engine. The purge gas amount stored in the first storage area from (M ≦ L) is moved from L number to LM + 1, and finally specified by the specifying unit from the LM number to the first storage area. The value obtained by using the purge gas amount is stored. The estimation unit estimates the purge gas amount sucked into the internal combustion engine using the purge gas amount stored in the Lth first storage region.

  In this configuration, the purge gas amount passing through the control valve is specified. The memory stores the amount of purge gas between the control valve and the internal combustion engine, divided into L parts corresponding to the L sections from the control valve to the internal combustion engine. Then, the purge gas amount in the memory is shifted in accordance with the intake amount of the internal combustion engine. Thus, the purge concentration at the determination position can be determined using the purge gas amount stored in the Lth storage area corresponding to the internal combustion engine in the memory. According to this configuration, the purge gas amount to be supplied to the internal combustion engine is determined in consideration of the delay between the timing at which the purge gas flow rate is specified and the timing at which the purge gas having the specified flow rate arrives at the internal combustion engine. Can do.

  Another technique disclosed in the present specification relates to a fuel vapor processing apparatus mounted on a vehicle. The evaporative fuel processing device is a canister that adsorbs evaporative fuel in a fuel tank and a purge path that connects an intake path and a canister of an internal combustion engine, and is more than a throttle valve and a supercharger disposed on the intake path. Arranged on the purge path connected to the upstream intake path, a communication state in which the canister and the intake path communicate with each other via the purge path, and a cutoff state in which the canister and the intake path are blocked on the purge path; The amount of purge gas in the gas sucked into the internal combustion engine is estimated by using the control valve that switches to, the specific part that repeatedly specifies the amount of purge gas that passes through the control valve per unit time, and the purge gas amount that has already been specified by the specific part An estimation unit. The estimation unit includes a memory having B storage areas from No. 1 to B (B is an integer of 2 or more), and a memory control unit. Each time the purge gas amount is specified, the memory control unit moves the evaporated fuel concentration stored in the storage area from No. 1 to B-1 to the storage area from No. 2 to B, and specifies the specified evaporation. The fuel concentration is stored in the first storage area. When the purge gas flows in the first flow path between the specific position and the determined position, the estimation unit stores the purge gas stored in the first to B storage areas in accordance with the intake air amount of the internal combustion engine. The amount of purge gas that is taken into the internal combustion engine is estimated using the purge gas amount stored in the storage area of No. C (integer of 1 ≦ C ≦ B) and the previously estimated purge gas amount. To do.

  In this configuration, the purge gas amount passing through the control valve is specified. The memory stores B purge gas amounts with different specified timings. The purge gas amount in the internal combustion engine is determined by using the C-th purge gas in accordance with the intake air amount among the B purge gas amounts in the memory and the previously determined purge gas amount. According to this configuration, the purge gas amount to be supplied to the internal combustion engine is determined in consideration of the delay between the timing at which the purge gas flow rate is specified and the timing at which the purge gas having the specified flow rate arrives at the internal combustion engine. Can do.

1 shows an outline of a fuel supply system for an automobile according to a first embodiment. The graph which shows the relationship between the pressure of the intake passage of 1st Example, and the amount of purge gas is shown. The schematic diagram for demonstrating the correspondence of the 2nd purge path | route of 1st Example and an upstream storage area is shown. The data map showing the relationship between the intake air amount and the shift number stored in the memory of the first embodiment is shown. The schematic diagram for demonstrating the correspondence of the 1st purge path | route of 1st Example and a downstream storage area is shown. The flowchart of the upstream purge gas amount determination process of 1st Example is shown. FIG. 4 is a schematic diagram for explaining a shift of the purge gas amount when the intake air amount is small in the memory corresponding to the purge path of the first embodiment. FIG. 4 is a schematic diagram for explaining a shift of the purge gas amount when the intake air amount is large in the memory corresponding to the purge path of the first embodiment. The flowchart of the downstream purge gas amount determination process of 1st Example is shown. The data map showing the relationship between the intake air amount stored in the memory of 2nd Example, a storage area number, and a coefficient is shown. The schematic diagram for demonstrating the shift of the purge density | concentration in the upstream storage area corresponding to the 2nd purge path | route of 2nd Example is shown. The schematic diagram for demonstrating the shift of the purge density | concentration in the downstream storage area corresponding to the 1st purge path | route of 2nd Example is shown. The flowchart of the purge gas amount storage process of 2nd Example is shown. The flowchart of the purge gas amount estimation process of 2nd Example is shown.

  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 fuel vapor processing apparatus of the present specification, the memory control unit may store the purge gas amount last specified by the specifying unit in the storage region from the LM number to the first number. According to this configuration, the purge gas amount can be stored in the storage region in accordance with the intake air amount.

(Characteristic 2) In the fuel vapor processing apparatus of the present specification, the estimation unit may estimate the purge gas amount in the gas sucked into the internal combustion engine by further using a coefficient determined in accordance with the intake air amount. According to this configuration, the purge gas amount can be corrected using a coefficient that matches the intake air amount.

(Characteristic 3) In the fuel vapor processing apparatus of the present specification, the estimation unit subtracts the previously estimated purge gas amount from the purge gas amount stored in the C-th storage area to the previously estimated purge gas amount. The amount of purge gas in the gas sucked into the internal combustion engine may be estimated by adding the value divided by the coefficient. According to this configuration, the purge gas amount in the internal combustion engine can be determined by using the purge gas amount in the internal combustion engine that has been determined last time, the purge gas amount stored in No. C, and the coefficient.

(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 and an exhaust pipe EP are connected to the engine EN. The intake pipe IP is a pipe for supplying air to the engine EN by the negative pressure of the engine EN or the operation of the supercharger CH. 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. A supercharger CH is arranged upstream of the throttle valve TV of the intake pipe IP. The supercharger CH is a so-called turbocharger, and rotates the turbine by the gas exhausted from the engine EN to the exhaust pipe EP, whereby the air in the intake pipe IP is pressurized and supplied to the engine EN. The supercharger CH is controlled by the ECU 100 to operate when the rotational speed N of the engine EN exceeds a predetermined rotational speed (for example, 2500 rotations).

  An air cleaner AC is disposed upstream of the supercharger CH 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.

  In a situation where the supercharger CH is stopped, negative pressure is generated in the intake pipe IP by driving the engine EN. In addition, when stopping the engine EN when the vehicle is stopped, or when the engine EN is stopped and the vehicle is driven by a motor like a hybrid vehicle, in other words, when the drive of the engine EN is controlled for environmental measures, the engine There is no or little negative pressure in the intake pipe IP due to the EN drive. On the other hand, in a situation where the supercharger CH is operating, the atmospheric pressure is upstream on the upstream side of the supercharger CH, while positive pressure is generated on the downstream side of the supercharger CH.

  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 check valves 80 and 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. 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, 24 and 26. The purge gas in the purge pipe 32 flows through the purge paths 22, 24, and 26 and is supplied to the intake path IW.

  The purge pipe 32 branches into two at a branch position 32a intermediate between the canister 14 and the intake path IW. One of the purge pipes 32 after branching is connected to the intake manifold IM on the engine EN side (that is, downstream) from the throttle valve TV and the supercharger CH, and the other of the purge pipes 32 after branching is connected to the throttle valve It is connected to the air cleaner AC side (that is, the upstream side) from the TV and the supercharger CH. A purge path 22 is defined by a purge pipe 32 closer to the canister 14 than the branch position 32a, and a purge path 24 is defined by a purge pipe 32 connected downstream from the branch position 32a of the purge pipe 32, A purge path 26 is defined by the purge pipe 32 connected upstream from the branch position 32 a of the purge pipe 32.

  A pump 12 is disposed at an intermediate position of the purge path 22. 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 of the pump 12 communicates with the canister 14 via the purge path 22.

  The discharge port of the pump 12 communicates with the purge pipe 32. The pump 12 delivers purge gas to the purge path 22. The purge gas sent to the purge path 22 passes through the purge path 24 or the purge path 26 and is supplied to the intake path IW.

  A check valve 83 is disposed at the end of the purge path 24 on the intake manifold IM side. 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. A check valve 80 is disposed at the end of the purge path 26 on the intake pipe IP side. The check valve 80 allows the gas to flow through the purge path 26 toward the intake path IW, and prohibits the gas from flowing toward the canister 14.

  A control valve 34 is disposed in the purge path 22 between the pump 12 and the branch position 32a. When the control valve 34 is closed, the purge gas in the purge path 22 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. Note that the purge path 22 located on the downstream side of the control valve 34 in the purge path 22 is referred to as a “purge path 22a”.

  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 (that is, the amount of intake air).

  Next, a purge process for supplying purge gas 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.

  In the purge process, purge gas is supplied from the canister 14 via the purge paths 22 and 24 to the intake path IW on the downstream side of the throttle valve TV, or from the canister 14 via the purge paths 22 and 26 and the supercharger. It is supplied to the intake path IW upstream of CH. Which route is supplied varies depending on whether or not the supercharger CH is operating.

  When the supercharger CH is not operating, the intake passage IW on the downstream side of the throttle valve TV becomes negative pressure by driving the engine EN. On the other hand, the intake path IW on the upstream side of the throttle valve TV is substantially equal to the atmospheric pressure. As a result, the purge gas is mainly supplied from the canister 14 via the purge paths 22 and 24 to the intake path IW (that is, in the intake manifold IM) on the downstream side of the throttle valve TV. A path of purge gas supplied from the control valve 34 to the engine EN through the purge paths 22a and 24 and the intake path IW is referred to as a first purge path FP.

  On the other hand, while the supercharger CH is operating, the air on the downstream side of the supercharger CH is pressurized by the supercharger CH. For this reason, the pressure of the intake passage IW is higher on the downstream side than the supercharger CH than on the upstream side of the supercharger CH. As a result, the purge gas is mainly supplied from the canister 14 via the purge paths 22 and 26 to the intake path IW on the downstream side of the supercharger CH. Note that the intake path IW on the downstream side of the supercharger CH approximates atmospheric pressure, and a slight negative pressure is generated by the supercharger CH. The path of the purge gas supplied from the control valve 34 to the engine EN through the purge paths 22a and 26 and the intake path IW is called a second purge path SP. The second purge path SP is longer than the first purge path FP.

  When the purge process is performed while the supercharger CH is operating, the control unit 102 drives the pump 12 to pump the purge gas, thereby supplying the purge gas to the intake passage IW on the upstream side of the supercharger CH. Is done. On the other hand, when the purge process is executed while the supercharger CH is not operating, the purge gas is supplied to the negative pressure intake path IW on the downstream side of the throttle valve TV. When the negative pressure of the intake passage IW is small and the purge gas is not sufficiently supplied to the intake passage IW due to, for example, the case where the engine EN has a low rotational speed, the control unit 102 drives the pump 12 to supply the purge gas to the intake passage IW. To supply. The control unit 102 controls to drive or stop the pump 12 according to the state of the negative pressure in the intake passage 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 air-fuel ratio of the engine EN to an optimum air-fuel ratio (for example, ideal air-fuel ratio) by adjusting the opening degree of the injector IJ and the duty ratio of the control valve 34.

  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 and the purge gas amount from the control valve 34.

  A method for estimating the purge gas amount supplied to the engine EN will be described. The amount of purge gas that passes through the control valve 34 varies depending on the pressure in the intake path IW, the duty ratio of the control valve 34, and whether or not the pump 12 is driven. For example, when the duty ratio is 100% (that is, when the control valve 34 is continuously opened) and the pump 12 is not operating, the purge gas amount is set to the intake path IW as shown in FIG. Decreases as pressure increases. Similar to FIG. 2, a data map indicating the correlation among the pressure of the intake path IW, the duty ratio of the control valve 34, whether the pump 12 is driven, and the purge gas amount is specified in advance by experiment and stored in the memory 104. Has been.

  As shown in FIG. 3, the memory 104 has 300 upstream storage areas 104 a (No. 1 and No. 2 are given symbols in FIG. 3) from No. 1 to No. 300. Each upstream storage area 104a stores the purge gas amount of each of the 300 partial paths 26a when the second purge path SP is divided into 300 equal parts by volume. 300 partial paths 26a from the control valve 34 to the engine EN correspond to the first to 300th upstream storage areas 104a in order from the control valve 34. The division of the purge path 26 and the like is not limited to the volume, and may be divided on the basis of the length.

  As shown in FIG. 5, the memory 104 further has 50 downstream storage areas 104 b (No. 1 and No. 2 in FIG. 5 are labeled). Each downstream storage area 104b stores the purge gas amount of each of the 50 partial paths 24a when the first purge path FP is divided into 50 equal parts by volume. Fifty partial paths 24a from the control valve 34 to the engine EN correspond to the first to 50th downstream storage areas 104b in order from the control valve 34. The division of the purge path 26 and the like is not limited to the volume, and may be divided on the basis of the length.

  As shown in FIG. 4, the memory 104 is further used in a data map 106 used in an upstream purge gas amount determination process (see FIG. 6) described later and in a downstream purge gas amount determination process (see FIG. 9). The data map 107 is stored. The data maps 106 and 107 are clarified in the purge gas amount determination process described later.

  When the ignition switch is turned on, the control unit 102 starts specifying the purge gas amount that passes through the control valve 34. The control unit 102 specifies the purge gas amount periodically (for example, every 16 ms) while the duty of the control valve 34 is controlled. Specifically, the control unit 102 specifies the purge gas amount from the data map of the memory 104 based on the pressure in the intake passage IW, the duty ratio of the control valve 34, and whether or not the pump 12 is driven.

  Independent of specifying the purge gas amount, the control unit 102 sequentially executes an upstream purge gas amount determination process shown in FIG. 6 and a downstream purge gas amount determination process shown in FIG. In the upstream purge gas amount determination process, the purge gas amount supplied to the engine EN through the second purge path SP is determined using the purge gas amount stored in the upstream storage region 104a. On the other hand, in the downstream purge gas amount determination process, the purge gas amount supplied to the engine EN through the first purge path FP is determined using the purge gas amount stored in the downstream storage region 104b.

  Each purge gas amount determination process is started 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 these purge gas amount determination processes are executed, default values are stored in the storage areas 104 a and 104 b of the memory 104. The contents in the storage areas 104a and 104b are replaced with default values when the ignition switch is switched from OFF to ON.

  As shown in FIG. 6, in the upstream purge gas amount determination process, first, in S12, the control unit 102 determines whether or not a default value is stored in all the upstream storage areas 104a. If default values are stored in all the upstream storage areas 104a (YES in S12), in S14, the control unit 102 stores 0 in all the upstream storage areas 104a and proceeds to S16. On the other hand, if a value other than the default value is stored in any of the upstream storage areas 104a (NO in S12), S14 is skipped and the process proceeds to S16.

  In the processing of S16 to S20, the purge gas amount stored in the upstream storage area 104a is shifted in accordance with the intake amount per unit time in the intake path IW. The intake air amount is a value obtained by adding the most recently specified purge gas amount to the value detected by the air flow meter 52. In S16, the control unit 102 specifies the number of the upstream storage area 104a to which the purge gas amount stored in the first upstream storage area 104a is moved (hereinafter referred to as “shift number”).

  As shown in FIG. 4, the memory 104 stores a data map 106 in which the intake amount per second and the shift number are associated with each other. The data map 106 is calculated in advance and stored in the memory 104. The data map 106 is calculated and created based on the following. In other words, the volume of the second purge path SP is 7 liters, the upstream storage area 104a is 300, and the execution period of the purge gas amount determination process is 16 ms.

  In this case, one upstream storage area 104a corresponds to a volume of 0.023 liters (≈7 liters / 300 pieces) of the second purge path SP. Therefore, when the intake amount per second is 0.023 liters / 16 ms≈1.44 liters / second, every time the purge gas amount determination process is executed (that is, every 16 ms) When the purge concentration in the upstream storage area 104a is stored in place of the purge gas amount stored in the No. 2 to 300 upstream storage areas 104a (that is, the shift number = 1), the purge gas flows. In addition, the purge gas amount in the upstream storage area 104a is shifted. Based on this, the number of shifts is determined in accordance with the intake amount per second. For example, when the intake amount per second is 10.0 liters / second, the shift number is 7 (≈10.0 / 1.44).

  In S <b> 16, the control unit 102 specifies the shift number (hereinafter, “300−M” (an integer of 1 ≦ M ≦ 300)) using the intake air amount and the data map 106. In S18, the control unit 102 replaces the purge gas amount stored in the 1st to Mth upstream storage areas 104a with the 300th to 300-M + 1th upstream storage areas 104a and stores the purge gas amount. As a result, the purge gas amount stored in the 300th upstream storage area 104a, that is, the purge gas amount supplied to the engine EN via the second purge path SP is updated. Note that the purge gas flows in the purge path 26 even when the supercharger CH is not operating. Therefore, the purge gas amount in the upstream storage area 104a is shifted regardless of whether or not the supercharger CH is operating. In the modification, the number of shifts may be changed in consideration of the amount of purge gas flowing through the purge path 26 depending on whether or not the blow-off valve of the supercharger CH is operating.

  Next, in S19, the control unit 102 determines whether or not the pressure of the intake manifold IM is equal to or higher than a predetermined value (for example, 90 kPa) using a pressure sensor that detects the pressure of the intake manifold IM (not shown). When the pressure of the intake manifold IM exceeds a predetermined value (that is, when the supercharger CH is operating) (YES in S19), the control unit 102 proceeds to S20. On the other hand, when the pressure of intake manifold IM does not exceed the predetermined value (that is, when supercharger CH is not operating) (NO in S19), the process proceeds to S21.

  In S20, the control unit 102 replaces the purge gas amount (that is, the latest purge gas amount) in the most recently specified control valve 34 with the upstream storage area 104a from No. 300-M and stores the purge gas amount. The decision process is terminated. On the other hand, in S21, the control unit 102 replaces and stores “0” in the upstream storage area 104a from No. 300-M to No. 1, and ends the purge gas amount determination processing. When the supercharger CH is not operating (NO in S19), the purge gas mainly flows into the first purge path FP, so the amount of purge gas flowing into the second purge path SP approximates “0”.

  In the evaporated fuel processing apparatus 10, the amount of purge gas that passes through the control valve 34 is specified. It takes time for the purge gas of the specified purge gas amount to reach the engine EN. In the purge gas amount determination process, the purge gas amount in the engine EN is changed as the purge gas flows through the second purge path SP.

  As shown in FIG. 7, when the intake air amount is relatively small at 2.0 liters / second and the shift number is specified as 300-M = 1 (ie, M = 299) in S16, the processing in S18 and S20 is performed. , The purge gas amounts α1 to α299 stored in the upstream storage regions 104a from No. 1 to 299 are respectively replaced with the purge gas amounts α2 to α300 stored in the upstream storage regions 104a from No. 2 to 300. Replace with and store. Then, the latest purge gas amount β is stored in the first upstream storage area 104a.

  On the other hand, as shown in FIG. 8, when the purge flow rate is relatively large as 144 liters / second and the shift number = 300−M = 100 (that is, M = 200) is specified in S16, the processing in S18 and S20 is performed. The purge gas amounts α1 to α200 stored in the upstream storage regions 104a from No. 1 to 200 are respectively replaced with the purge gas amounts α101 to α300 stored in the upstream storage regions 104a from No. 101 to 300. Replace with and store. Then, the latest purge gas amount β is stored in the first to 100th upstream storage areas 104a.

  According to this configuration, the amount of purge gas supplied to the engine EN through the second purge path SP can be changed in accordance with the intake air amount.

  When the upstream purge gas amount determination process is completed, the downstream purge gas amount determination process shown in FIG. 9 is subsequently executed. In the downstream purge gas amount determination process, first, the processes of S112 to S118 similar to S12 to S18 of the upstream purge gas amount determination process are executed. In S116, the control unit 102 specifies the number of the downstream storage area 104b to which the purge gas amount stored in the first downstream storage area 104b is moved (hereinafter referred to as “shift number”). To do.

  As shown in FIG. 4, the memory 104 stores a data map 107 in which an intake amount per second and a shift number are associated with each other. The data map 107 is calculated in advance and stored in the memory 104. The data map 107 is calculated and created based on the following. In other words, the volume of the first purge path FP is 1.2 liters, the downstream storage area 104b is 50, and the execution period of the purge gas amount determination process is 16 ms.

  In this case, one downstream storage area 104b corresponds to a volume of 0.023 liters (≈1.2 liters / 50 pieces) of the first purge path FP. For this reason, when the intake amount per second is 0.023 liters / 16 ms≈1.44 liters / second, every time the purge gas amount determination process is executed (that is, every 16 ms) When the purge concentration in the downstream storage area 104a is stored in place of the purge gas amount stored in the second to 50th downstream storage areas 104b (that is, the shift number = 1), the purge gas flow is changed. In addition, the purge gas amount in the downstream storage area 104b is shifted. Based on this, the number of shifts is determined in accordance with the intake amount per second. For example, when the intake amount per second is 10.0 liters / second, the shift number is 7 (≈10.0 / 1.44).

  In S116, the control unit 102 specifies the number of shifts (hereinafter referred to as “50−Y” (1 ≦ Y ≦ 50)) using the intake air amount and the data map 107. In subsequent S118, the control unit 102 replaces the purge gas amount stored in the 1st to Yth downstream storage areas 104b with the 50th to 50-Y + 1th downstream storage areas 104b and stores them. Thereby, the purge gas amount stored in the 50th downstream storage area 104b, that is, the purge gas amount supplied to the engine EN through the first purge path FP is updated. Note that the purge gas flows in the purge path 24 even when the supercharger CH is operating. For this reason, the purge gas amount in the downstream storage area 104b is shifted regardless of whether or not the supercharger CH is operating. In the modification, the number of shifts may be changed in consideration of the amount of purge gas flowing through the purge path 24 depending on whether the blow-off valve of the supercharger CH is operating.

  Next, in S119, the control unit 102 determines whether or not the pressure of the intake manifold IM is less than a predetermined value (for example, 90 kPa) using a pressure sensor that detects the pressure of the intake manifold IM. When the pressure of the intake manifold IM is less than the predetermined value (that is, when the supercharger CH is not operating) (YES in S119), the control unit 102 proceeds to S120. On the other hand, when the pressure of intake manifold IM is equal to or higher than the predetermined value (that is, when supercharger CH is operating) (NO in S119), the process proceeds to S121.

  In S120, the control unit 102 replaces and stores the latest purge gas amount in the 50-Y to No. 1 downstream storage area 104b, and ends the downstream purge gas amount determination processing. On the other hand, in 1S21, the control unit 102 replaces and stores “0” in the downstream storage area 104b from No. 50-Y to No. 1, and ends the purge gas amount determination processing. When the supercharger CH is operating (NO in S119), the purge gas mainly flows into the second purge path SP, so the amount of purge gas flowing into the first purge path FP approximates “0”.

  In the evaporated fuel processing apparatus 10, the amount of purge gas that passes through the control valve 34 is specified. It takes time for the purge gas of the specified purge gas amount to reach the engine EN. In the purge gas amount determination process, the purge gas amount in the engine EN is changed as the purge gas flows through the first purge path FP.

  According to the downstream purge gas amount determination process, as in the upstream purge gas amount determination process, the shift number is large when the intake amount is relatively large, and the shift number is small when the intake amount is relatively small. According to this configuration, the amount of purge gas supplied to the engine EN through the first purge path FP can be changed in accordance with the intake air amount.

  The control unit 102 determines the total purge gas amount of the purge gas amount currently stored in the No. 300 upstream storage region 104a and the purge gas amount stored in the No. 50 downstream storage region 104b as the engine EN It can be estimated that the amount of purge gas supplied to.

  The ECU 100 adjusts the opening degree of the injector IJ so that the air-fuel ratio detected by the air-fuel ratio sensor 50 becomes a predetermined reference air-fuel ratio (for example, ideal air-fuel ratio), and fuel injection supplied to the engine EN Control the amount. When the purge process is executed, the air-fuel ratio changes to the rich side. At this time, the ECU 100 assumes that the purge concentration is a predetermined X%. Then, using the estimated purge gas amount, the amount of fuel supplied by the purge process is specified. The ECU 100 controls the fuel injection amount by adjusting the opening degree of the injector IJ based on the specified fuel amount (that is, reducing the fuel injection amount). At this time, when the air-fuel ratio is maintained rich, the ECU 100 further adds X% to the assumed purge concentration and specifies the amount of fuel supplied by the purge process in the same manner as described above. The ECU 100 repeats the above processing so that the air-fuel ratio becomes the reference air-fuel ratio. If the purge gas amount supplied to the engine EN by the purge process is appropriately estimated, the air-fuel ratio can be controlled to the reference air-fuel ratio at an early stage after the purge process is started.

(Second embodiment)
In the second embodiment, the upstream and downstream purge gas amount estimation processes executed by the control unit 102 are different. As shown in FIG. 11, the memory 104 has 313 upstream storage areas 204a instead of the upstream storage area 104a of the first embodiment. The upstream storage area 204a does not correspond to the section of the second purge path SP. Further, as shown in FIG. 12, the memory 104 has 53 downstream storage areas 204b instead of the downstream storage area 104b of the first embodiment.

  The control unit 102 executes a purge gas amount storage process every time the purge gas amount is specified periodically. As shown in FIG. 13, in the purge gas amount storing process, in S72, the controller 102 determines whether or not the pressure of the intake manifold IM is equal to or higher than a predetermined value (for example, 90 kPa), as in S19 of FIG. . When the pressure of the intake manifold IM exceeds a predetermined value (that is, when the supercharger CH is operating) (YES in S72), the control unit 102 proceeds to S74. On the other hand, when the pressure of intake manifold IM does not exceed the predetermined value (that is, when supercharger CH is not operating) (NO in S72), the process proceeds to S78.

  In S74, the control unit 102 changes the purge gas amounts α1 to α312 stored in the 1st to 312th upstream storage areas 204a to the purge gas stored in the 2nd to 313th upstream storage areas 204a. It replaces and stores in each of quantity α2-α313. Then, the control unit 102 stores the latest purge gas amount β in the first upstream storage area 204a. Next, in S76, as shown in FIG. 12, the control unit 102 changes the purge gas amounts γ1 to γ52 stored in the 1st to 52nd downstream storage areas 204b to the 2nd to 53rd storage areas. The purge gas amounts γ2 to γ53 stored in 204b are replaced and stored. Then, the control unit 102 stores “0” in the first downstream storage area 204b and ends the purge gas amount storage process. Accordingly, since the pressure of the intake manifold IM is high and the purge gas that has passed through the control valve 34 is supplied to the second purge path SP, the latest purge gas amount β is stored in the first upstream storage area 204a. At this time, almost no purge gas is supplied from the control valve 34 to the first purge path FP, and “0” is stored in the first downstream storage area 204b.

  On the other hand, in S78, the control unit 102 changes the purge gas amounts α1 to α312 stored in the upstream storage area 204a from No. 1 to 312 to the purge gas stored in the storage area 204a from No. 2 to 313, respectively. It replaces and stores in each of quantity α2-α313. Then, the control unit 102 stores “0” in the first upstream storage area 204a. Next, in S80, the control unit 102 stores the purge gas amounts γ1 to γ52 stored in the 1st to 52nd downstream storage areas 204b in the 2nd to 53rd downstream storage areas 204b. The purge gas amounts γ2 to γ53 are replaced and stored. Then, as shown in FIG. 12, the control unit 102 stores the latest purge gas amount δ in the first downstream storage area 204b, and ends the purge gas amount storage process. Accordingly, since the pressure of the intake manifold IM is low and the purge gas that has passed through the control valve 34 is supplied to the first purge path FP, the latest purge gas amount δ is stored in the first downstream storage region 204b. At this time, almost no purge gas is supplied from the control valve 34 to the second purge path SP, and “0” is stored in the first upstream storage area 204a.

  As shown in FIG. 10, the memory 104 stores data maps 206 and 207 in which the intake amount per second, the number, and the coefficient are associated with each other instead of the data maps 106 and 107. The data maps 206 and 207 are calculated in advance and stored in the memory 104. The data map 206 is calculated and created as follows. That is, when the volume of the second purge path SP is 7.0 liters, and the minimum value of the intake air amount is 1.4 liters / second, the purge gas passes through the second purge path SP with the minimum purge flow rate. It takes 5000ms to flow from the engine to the engine EN. If the execution cycle of the upstream determination process is 16 ms, 5000 ms / 16 ms = 313 upstream storage areas 204a are prepared, and the No. 313 upstream storage area when the purge flow rate is 1.4 liters / second. 204a is selected. The upstream coefficient is used when calculating the purge gas amount in S54 described later.

  The data map 207 is calculated and created as follows. That is, when the volume of the second purge path SP is 1.2 liters, when the minimum value of the intake air amount is 1.4 liters / second, the purge gas passes through the second purge path SP with the minimum purge flow rate. It takes 850 ms to flow from the engine to the engine EN. Assuming that the execution cycle of the upstream determination process is 16 ms, the downstream storage area 204b of 850 ms / 16 ms = 53 is selected when the purge flow rate is 1.4 liters / second. The downstream coefficient is used when calculating the purge gas amount in S56 described later.

  Next, a purge gas amount estimation process for estimating the purge gas amount in the engine EN will be described. As shown in FIG. 14, in the purge gas amount estimation process, first, in S52, the control unit 102 uses the intake air amount detected by the air flow meter 52 and the data maps 206 and 207 to store the upstream storage area 204a. And the downstream coefficient are identified, and the downstream storage area 204b number and the downstream coefficient are identified. Next, in S54, the control unit 102 determines the upstream purge gas amount estimated in the previous S54 (default value (for example, “0”) in the absence) (hereinafter referred to as “upstream previous gas amount”), and in S52. Using the purge gas amount (hereinafter referred to as “upstream specific gas amount”) stored in the upstream storage area 204a of the number identified from the data map 206 and the coefficient, the upstream previous gas amount + ( By calculating (upstream specific gas amount−upstream previous gas amount) / coefficient, the upstream purge gas amount supplied from the second purge path SP is estimated. When the intake amount is 75.0 liters / second or more, the number of the downstream storage area 204b is 1, and the downstream coefficient is 1.

  Next, in S56, the control unit 102 determines the downstream purge gas amount estimated in the previous S56 (default value (for example, “0”) in the absence) (hereinafter referred to as “downstream previous gas amount”), and in S52. Using the purge gas amount (hereinafter referred to as “downstream specific gas amount”) stored in the downstream storage area 204b of the number specified from the data map 207 and the coefficient, the downstream previous gas amount + ( By calculating (downstream specific gas amount−downstream previous gas amount) / coefficient, the downstream purge gas amount supplied from the first purge path FP is estimated.

  Next, in S58, the control unit 102 estimates the sum of the upstream purge gas amount estimated in S54 and the downstream purge gas amount estimated in S56 as the purge gas amount in the engine EN.

  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.

  For example, in each of the above embodiments, the second purge path SP connected to the upstream side of the supercharger CH and the first purge path FP connected to the downstream side of the supercharger CH are provided. . However, the first purge path FP may not be provided. In this case, in the purge gas amount estimation process, the estimation may be performed without considering the purge gas amount from the first purge path FP.

  Further, for example, in the first embodiment described above, the data maps 106 and 107 associate the intake air amount and the shift number. However, the parameter associated with the shift number may be a plurality of parameters including the engine speed, the purge gas amount, and the pressure on the downstream side of the supercharger CH in addition to the intake air amount. In this case, a data map in which a plurality of parameters and shift numbers are associated may be specified in advance and stored in the memory 104. Further, the control unit 102 may specify a plurality of parameters in S16 of FIG. 6 and S116 of FIG. 9, and may specify the number of shifts associated with the specified plurality of parameters from the data maps 106 and 107. .

  Further, for example, in the second embodiment, the data maps 206 and 207 are associated with the intake air amount, the storage area number, and the coefficient. However, the parameter associated with the delivery area number and the coefficient may be a plurality of parameters including the engine speed and the purge gas amount in addition to the intake air amount. In this case, a data map in which a plurality of parameters, storage area numbers, and coefficients are associated may be specified in advance and stored in the memory 104. Further, in S52 of FIG. 14, the control unit 102 may specify a plurality of parameters, and specify a storage area number and a coefficient associated with the specified parameters from the data maps 206 and 207.

  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 14: Canisters 22, 24, 26: Purge path 34: Control valve 100: ECU
102: Control unit 104: Memory 104a: Upstream storage area 104b: Downstream storage area 204a: Upstream storage area 204b: Downstream storage area CH: Supercharger EN: Engine FP: First purge path IM: Intake manifold IW : Intake path SP: Second purge path TV: Throttle valve

Claims (5)

An evaporative fuel processing device mounted on a vehicle,
A canister that adsorbs the evaporated fuel in the fuel tank;
A purge path that connects an intake path of an internal combustion engine and a canister, and is disposed on a purge path that is connected to an intake path upstream of a throttle valve and a supercharger that are disposed on the intake path. A control valve that switches between a communication state in which the intake path and the intake path are communicated via the purge path, and a shut-off state in which the canister and the intake path are blocked on the purge path;
A specific unit that repeatedly specifies the amount of purge gas that passes through the control valve per unit time;
An estimation unit that estimates the purge gas amount in the gas sucked into the internal combustion engine using the purge gas amount that has been identified in the identification unit;
The estimation part is
A memory having storage areas of L from No. 1 to L (L is an integer of 2 or more);
A memory control unit,
The memory controller
A flow path in which purge gas flows between the control valve and the internal combustion engine in order from the control valve to the internal combustion engine in the Kth storage area (K is an integer of 1 ≦ K ≦ L) among the L storage areas. Stores the amount of purge gas located in the Kth section when divided into L sections from No. 1 to L,
In accordance with the intake air amount of the internal combustion engine, the purge gas amount stored in the No. 1 storage area from No. M (M is an integer of 1 ≦ M ≦ L) is moved from No. L to No. L−M + 1. In the storage area from No. M to No. 1, the value obtained by using the purge gas amount last specified by the specifying unit is stored,
The estimation unit estimates an amount of purge gas taken into the internal combustion engine using an amount of purge gas stored in the Lth first storage region.   The evaporated fuel processing apparatus according to claim 1, wherein the memory control unit stores the purge gas amount specified last by the specifying unit in a storage region from the LM number to the first number. An evaporative fuel processing device mounted on a vehicle,
A canister that adsorbs the evaporated fuel in the fuel tank;
A purge path that connects an intake path of an internal combustion engine and a canister, and is disposed on a purge path that is connected to an intake path upstream of a throttle valve and a supercharger that are disposed on the intake path. A control valve that switches between a communication state in which the intake path and the intake path are communicated via the purge path, and a shut-off state in which the canister and the intake path are blocked on the purge path;
A specific unit that repeatedly specifies the amount of purge gas that passes through the control valve per unit time;
An estimation unit that estimates the purge gas amount in the gas sucked into the internal combustion engine using the purge gas amount that has been identified in the identification unit;
The estimation part is
A memory having B storage areas from 1 to B (B is an integer of 2 or more);
A memory control unit,
Each time the purge gas amount is specified, the memory control unit moves the evaporated fuel concentration stored in the storage area from No. 1 to B-1 to the storage area from No. 2 to B, and specifies the specified evaporation. Store the fuel concentration in the first storage area,
When the purge gas flows in the first flow path between the specific position and the determined position, the estimation unit stores the purge gas stored in the first to B storage areas in accordance with the intake air amount of the internal combustion engine. The amount of purge gas that is taken into the internal combustion engine is estimated using the purge gas amount stored in the storage area of No. C (integer of 1 ≦ C ≦ B) and the previously estimated purge gas amount. Evaporative fuel processing device.   The evaporative fuel processing apparatus according to claim 3, wherein the estimation unit further estimates a purge gas amount in the gas sucked into the internal combustion engine using a coefficient determined according to the intake air amount.   The estimation unit adds the value obtained by subtracting the previously estimated purge gas amount from the purge gas amount stored in the C-th storage area to the previously estimated purge gas amount and dividing the result by the coefficient. The evaporative fuel processing apparatus according to claim 4, wherein the amount of purge gas in the gas sucked in is estimated.

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