JP2022089478A - Engine device - Google Patents

Abstract

To detect boiling of fuel in a fuel tank.SOLUTION: A target discharge flow rate of a fuel pump is set by using feedback control using a proportional term and an integration term on the basis of a difference between fuel pressure that is pressure of fuel in a fuel flow passage and a target fuel pressure to control the fuel pump. In this case, a difference is calculated by subtracting a second processing value obtained by applying annealing processing of second responsiveness lower than first responsiveness to the integration term from the integration term or a first processing value obtained by applying annealing processing of the first responsiveness to the integration term in the feedback control, and when the calculated difference is a difference threshold value or greater, boiling of the fuel in the fuel tank is detected.SELECTED DRAWING: Figure 12

Description

The present invention relates to an engine device.

Conventionally, this type of engine device includes an injector, a fuel rail connected to the injector, a high-pressure pump that pumps fuel to the fuel rail via the high-pressure fuel line, and a high-pressure pump via the low-pressure fuel line. A low-pressure pump for pumping fuel has been proposed (see, for example, Patent Document 1). In this engine device, the discharge amount of the high-pressure pump is controlled by using feedback control by the proportional term and the integral term based on the deviation between the pressure in the fuel rail and the target value. Then, when the average increase rate of the integral term in the feedback control is larger than the reference increase rate, it is determined that vapor is generated in the low pressure side fuel line. This is because when vapor is generated in the low pressure side fuel line, the rail pressure does not reach the target rail pressure because the fuel does not flow properly into the high pressure pump, and the integral term of the feedback control continues to increase. It is based on.

Japanese Unexamined Patent Publication No. 2017-31958

By the way, in an engine device including an engine and a fuel supply device having a fuel pump for supplying fuel in a fuel tank to a fuel flow path connected to a fuel injection valve of the engine, the same as the control of the high pressure pump described above. It is considered to control the discharge amount (rotation speed) of the fuel pump by using the feedback control by the proportional term and the integral term so that the fuel pressure in the fuel flow path becomes the target fuel pressure. In such an engine device, it is useful for improving the technique to devise a method different from the above for detecting boiling of fuel in the fuel tank (generation of vapor in the fuel flow path based on the boiling). .. The fuel in the fuel tank boils when the absolute pressure in the fuel tank is equal to or less than the saturated vapor pressure of the fuel. Therefore, the fuel in the fuel tank tends to boil when the altitude is high and the atmospheric pressure is low, or when the temperature of the fuel in the fuel tank is high and the saturated vapor pressure of the fuel is high.

An object of the engine device of the present invention is to propose a method different from the above-mentioned method for detecting boiling of fuel in a fuel tank.

The engine device of the present invention has adopted the following means in order to achieve the above-mentioned main object.

The engine device of the present invention
With the engine
A fuel supply device having a fuel pump for supplying fuel in a fuel tank to a fuel flow path connected to a fuel injection valve of the engine.
Control to control the fuel pump by setting the target discharge flow rate of the fuel pump using feedback control by the proportional term and the integral term based on the difference between the fuel pressure which is the pressure of the fuel in the fuel flow path and the target fuel pressure. With the equipment
It is an engine device equipped with
The control device has a second responsiveness lower than the first responsiveness to the integral term from the first processing value obtained by subjecting the integral term or the integral term to the first responsive tanning process. Further, the difference is calculated by subtracting the second processing value obtained by performing the processing, and when the difference is equal to or greater than the difference threshold, boiling of the fuel in the fuel tank is detected.
The gist is that.

In the engine device of the present invention, the target discharge flow rate of the fuel pump is set by using the feedback control by the proportional term and the integral term based on the difference between the fuel pressure which is the pressure of the fuel in the fuel flow path and the target fuel pressure. To control. In this case, from the first processing value obtained by subjecting the integral term or the integral term in the feedback control to the first responsive smoothing process, the integral term is subjected to the second responsive smoothing process which is lower than the first responsiveness. The second processing value obtained by applying the above is subtracted to calculate the difference, and when the calculated difference is equal to or greater than the difference threshold value, boiling of the fuel in the fuel tank is detected. When the fuel in the fuel tank is boiling and the fuel pump sucks in vaporized fuel (mainly fuel vaporized by boiling) and the discharge pressure of the fuel pump decreases, the fuel pressure becomes lower than the target fuel pressure, and the integration in feedback control. The term increases. Since the responsiveness (following property) to the integral term is different between the integral term or the first processing value and the second processing value, the difference condition obtained by subtracting the second processing value from the integration term or the first processing value is used. This makes it possible to appropriately detect the boiling of the fuel in the fuel tank.

In the engine device of the present invention, the control device may set the difference threshold value so that it becomes smaller when the atmospheric pressure is low than when it is high. In this way, the difference threshold can be set more appropriately based on the atmospheric pressure.

In the engine device of the present invention, the control device detects fuel pressure convergence, which is the convergence of the fuel pressure, and detects boiling of fuel in the fuel tank when the difference is equal to or greater than the difference threshold value. It may be the one to do. By doing so, it is possible to suppress erroneous detection of boiling of fuel in the fuel tank.

In this case, the control device said that when the fuel pressure difference between the target fuel pressure and the fuel pressure or the pulsating center fuel pressure which is the pulsating center of the fuel pressure is equal to or less than the fuel pressure difference threshold value and the duration thereof is a predetermined time or longer. It may be used to detect the convergence of fuel pressure. When the engine operation is controlled, the fuel pressure pulsates due to the influence of fuel injection from the fuel injection valve. Therefore, when the difference between the target fuel pressure and the pulsating center fuel pressure is used, it is possible to easily detect the convergence of the fuel pressure as compared with the case where the difference between the target fuel pressure and the fuel pressure is used. In this case, the control device may perform a tanning process on the fuel pressure to estimate the pulsating center fuel pressure.

In the engine device of the present invention, the control device detects boiling of fuel in the fuel tank when the update duration of the integration term is equal to or longer than a predetermined time and the difference is equal to or longer than the difference threshold value. It may be the one to do. Further, the control device may detect boiling of fuel in the fuel tank when the fuel consumption flow rate of the engine is stable and the difference is equal to or larger than the difference threshold value. By doing so, it is possible to suppress erroneous detection of boiling of fuel in the fuel tank.

In the engine device of the present invention, the control device detects the convergence of the fuel pressure, which is the convergence of the fuel pressure, from the integration term or the first processing value, and the integration term or the integration at the time of convergence, which is the first processing value. The second difference may be calculated by subtracting the term or the processing value at the time of convergence, and the boiling of the fuel in the fuel tank may be detected even when the second difference is equal to or larger than the second difference threshold. By doing so, the boiling of the fuel in the fuel tank can be appropriately detected by using the condition of the second difference obtained by subtracting the convergence term or the convergence processing value from the integration term or the first processing value. can.

In the engine device of the present invention in which the boiling of fuel in the fuel tank is detected when the second difference is equal to or larger than the second difference threshold, the control device is smaller when the atmospheric pressure is low than when it is high. The second difference threshold may be set so as to be. In this way, the second difference threshold can be set more appropriately based on the atmospheric pressure.

In the engine device of the present invention in the embodiment of detecting the boiling of fuel in the fuel tank when the second difference is equal to or more than the second difference threshold, the control device has an update duration of the integration term of a predetermined time or more. Moreover, when the second difference is equal to or greater than the second difference threshold, boiling of the fuel in the fuel tank may be detected. Further, the control device detects boiling of fuel in the fuel tank when the fuel consumption flow rate of the engine is stable and the second difference is equal to or higher than the second difference threshold value. May be. By doing so, it is possible to suppress erroneous detection of boiling of fuel in the fuel tank.

The engine device of the present invention further includes a vaporized fuel processing device capable of purging to supply the vaporized fuel gas containing the vaporized fuel generated in the fuel tank to the intake pipe of the engine, and the control device comprises the purge. Even when the purge concentration, which is the concentration of, is higher than the concentration threshold value, the boiling of the fuel in the fuel tank may be detected. By doing so, the boiling of the fuel in the fuel tank can be appropriately detected by using the condition of the purge concentration.

In the engine device of the present invention in which the boiling of fuel in the fuel tank is detected when the purge concentration is higher than the concentration threshold value, the control device is made thinner when the atmospheric pressure is low than when it is high. The concentration threshold may be set. In this way, the concentration threshold can be set more appropriately based on the atmospheric pressure.

The engine device of the present invention further includes a vaporized fuel processing device capable of purging to supply the vaporized fuel gas containing the vaporized fuel generated in the fuel tank to the intake pipe of the engine, and the control device comprises the purge. When the purge concentration, which is the concentration of, is equal to or less than the second concentration threshold value, the boiling of the fuel in the fuel tank may be undetected. By doing so, the boiling of the fuel in the fuel tank can be undetected by using the condition of the purge concentration.

In the engine device of the present invention in which boiling of fuel in the fuel tank is not detected when the purge concentration is lower than the second concentration threshold, the control device is used when the atmospheric pressure is low as compared with when the atmospheric pressure is high. The second concentration threshold may be set so as to be thin. In this way, the second concentration threshold can be set more appropriately based on the atmospheric pressure.

In the engine device of the present invention in which boiling of fuel in the fuel tank is not detected when the purge concentration is lower than the second concentration threshold, the purge concentration is equal to or less than the second concentration threshold and the purge is said. When the number of times of learning the concentration is more than a predetermined number of times and / or the pressure in the fuel tank is less than the predetermined pressure, boiling of the fuel in the fuel tank may be undetected. By doing so, the boiling of the fuel in the fuel tank can be undetected by using the conditions of the purge concentration and the number of learnings thereof and / or the pressure in the fuel tank.

In the engine device of the present invention, the control device may not detect boiling of fuel in the fuel tank when the cooling water temperature is less than the water temperature threshold. Further, the control device may not detect boiling of fuel in the fuel tank when the intake air temperature is less than the intake air temperature threshold value. Further, the control device may not detect boiling of the fuel in the fuel tank when the fuel temperature, which is the temperature of the fuel in the fuel tank, is less than the fuel temperature threshold value. By doing so, boiling of the fuel in the fuel tank can be undetected by using the conditions of the cooling water temperature, the intake air temperature, and the fuel temperature. Here, the fuel temperature may be estimated based on the intake air temperature.

In the engine device of the present invention in which boiling of fuel in the fuel tank is not detected when the intake air temperature is less than the intake air temperature threshold, the control device is lower when the atmospheric pressure is low than when it is high. The intake air temperature threshold may be set so as to be. In this way, the intake air temperature threshold can be set more appropriately based on the atmospheric pressure.

The engine device of the first modification of the present invention is
With the engine
A fuel supply device having a fuel pump for supplying fuel in a fuel tank to a fuel flow path connected to a fuel injection valve of the engine.
Control to control the fuel pump by setting the target discharge flow rate of the fuel pump using feedback control by the proportional term and the integral term based on the difference between the fuel pressure which is the pressure of the fuel in the fuel flow path and the target fuel pressure. With the equipment
It is an engine device equipped with
The control device detects the convergence of the fuel pressure, which is the convergence of the fuel pressure, from the processing value obtained by performing the integration processing on the integration term or the integration term, and the integration term or the integration at the time of convergence, which is the processing value. The difference is calculated by subtracting the term or the processing value at the time of convergence, and when the difference is equal to or greater than the difference threshold, boiling of the fuel in the fuel tank is detected.
The gist is that.

In the engine device of the first modification of the present invention, the target discharge flow rate of the fuel pump is set by using feedback control by the proportional term and the integral term based on the difference between the fuel pressure which is the pressure of the fuel in the fuel flow path and the target fuel pressure. Set to control the fuel pump. In this case, the integral term or the integrated term at the time of convergence, which is the processed value, when the fuel pressure convergence, which is the convergence of the fuel pressure, is detected from the processed value obtained by performing the integral term or the integral term in the feedback control. The time processing value is subtracted to calculate the difference, and when the calculated difference is equal to or greater than the difference threshold, boiling of the fuel in the fuel tank is detected. When the fuel in the fuel tank is boiling and the fuel pump sucks in vaporized fuel (mainly fuel vaporized by boiling) and the discharge pressure of the fuel pump decreases, the fuel pressure becomes lower than the target fuel pressure, and the integration in feedback control. The term increases. Therefore, boiling of fuel in the fuel tank can be appropriately detected by using the difference condition obtained by subtracting the convergence term or the convergence processing value from the integration term or the processing value.

The engine device of the second modification of the present invention is
With the engine
A fuel supply device having a fuel pump for supplying fuel in a fuel tank to a fuel flow path connected to a fuel injection valve of the engine.
A vaporized fuel processing device capable of purging to supply a vaporized fuel gas containing vaporized fuel generated in the fuel tank to the intake pipe of the engine, and a vaporized fuel processing apparatus.
With the control device
It is an engine device equipped with
The control device detects boiling of fuel in the fuel tank when the purge concentration, which is the concentration of the purge, is higher than the concentration threshold value.
The gist is that.

In the engine device of the second modification of the present invention, boiling of fuel in the fuel tank is detected when the purge concentration, which is the concentration of the purge, is higher than the concentration threshold value. When the fuel in the fuel tank is boiling, more vaporized fuel is generated in the fuel tank than when it is not boiling. Further, it is assumed that the higher the purge concentration, the more vaporized fuel is generated in the fuel tank. From these facts, the boiling of the fuel in the fuel tank can be appropriately detected by using the condition of the purge concentration.

It is a block diagram which shows the outline of the structure of the automobile 10 provided with the engine device 11 as an embodiment of this invention. It is a flowchart which shows an example of the fuel injection control routine executed by an electronic control unit 70. It is a flowchart which shows an example of the purge density | concentration-related value setting routine executed by an electronic control unit 70. It is explanatory drawing which shows an example of the map for setting the update amount. It is a flowchart which shows a part of an example of a fuel pump control routine executed by an electronic control unit 70. It is a flowchart which shows a part of an example of a fuel pump control routine executed by an electronic control unit 70. It is a flowchart which shows a part of an example of a fuel pump control routine executed by an electronic control unit 70. It is explanatory drawing which shows an example of the map for setting a feed forward term. It is explanatory drawing which shows an example of the map for setting a target rotation speed. It is a flowchart which shows a part of an example of the fuel boiling detection flag setting routine executed by an electronic control unit 70. It is a flowchart which shows a part of an example of the fuel boiling detection flag setting routine executed by an electronic control unit 70. It is a flowchart which shows a part of an example of the fuel boiling detection flag setting routine executed by an electronic control unit 70. It is a flowchart which shows an example of the fuel pressure convergence detection flag setting routine executed by an electronic control unit 70. It is explanatory drawing which shows an example of the state of the target fuel pressure Pf *, the fuel pressure Pf, the feedback integral term αbi, the high response processing value βhi, the low response processing value βlo, the difference Δβ1, and the provisional detection flag Fv2b. It is explanatory drawing which shows an example of the state of the target fuel pressure Pf *, the fuel pressure Pf, the feedback integral term αbi, the high response processing value βhi, the low response processing value βlo, the difference Δβ1, Δβ, and the provisional detection flags Fv2b, Fv2c. It is a flowchart which shows a part of an example of a fuel pump control routine executed by an electronic control unit 70. It is explanatory drawing which shows an example of the state of the target fuel pressure Pf *, the fuel pressure Pf, the feedback integral term αbi, the high response processing value βhi, the fuel pressure convergence detection flag Fpc, and the fuel boiling detection flag Fv. It is a flowchart which shows an example of a feedback integral term setting process. It is explanatory drawing which shows an example of the map for setting the 1st purge density threshold. It is explanatory drawing which shows an example of the map for setting an intake air temperature threshold. It is explanatory drawing which shows an example of the map for setting the 2nd purge density threshold value. It is explanatory drawing which shows an example of the 1st difference threshold setting map. It is explanatory drawing which shows an example of the 2nd difference threshold setting map.

Next, an embodiment for carrying out the present invention will be described with reference to examples.

FIG. 1 is a configuration diagram showing an outline of the configuration of an automobile 10 including an engine device 11 as an embodiment of the present invention. As shown in the figure, the automobile 10 of the embodiment is connected to the engine 12, the fuel supply device 42, the vaporized fuel processing device 50, and the crankshaft 14 of the engine 12, and the drive wheels 64a, via the differential gear 62. It includes a transmission 60 connected to 64b, a starter (not shown) for starting the engine 12, and an electronic control unit 70 for controlling the entire vehicle. The engine device 11 of the embodiment mainly corresponds to the engine 12, the fuel supply device 42, the vaporized fuel processing device 50, and the electronic control unit 70.

The engine 12 is configured as an internal combustion engine that outputs power by four strokes of intake, compression, expansion, and exhaust using fuel such as gasoline or light oil from the fuel tank 40. The engine 12 sucks the air cleaned by the air cleaner 22 into the intake pipe 23 and passes it through the throttle valve 24, and injects fuel from the fuel injection valve 26 on the downstream side of the throttle valve 24 of the intake pipe 23 to produce air. And fuel. Then, this air-fuel mixture is sucked into the combustion chamber 29 through the intake valve 28, explosively burned by the electric spark of the ignition plug 30, and the reciprocating motion of the piston 32 pushed down by the energy of the explosive combustion is converted into the rotational motion of the crank shaft 14. Convert. The exhaust gas discharged from the combustion chamber 29 to the exhaust pipe 34 via the exhaust valve 33 is discharged to the outside air through the purification device 35. The purification device 35 has a catalyst (three-way catalyst) 35a that purifies harmful components of carbon monoxide (CO), hydrocarbons (HC), and nitrogen oxides (NOx).

The fuel supply device 42 is configured to be able to supply the fuel in the fuel tank 40 to the fuel injection valve 26. The fuel supply device 42 includes a fuel flow path 43, a fuel pump 44, a relief passage 45, and a relief valve 46. The fuel flow path 43 is connected to the fuel injection valve 26. The fuel pump 44 supplies the fuel in the fuel tank 40 to the fuel flow path 43. The fuel pump 44 is formed with a discharge hole 44a for discharging the vaporized fuel by driving the fuel pump 44 when the vaporized fuel (fuel vaporized by evaporation or boiling) generated in the fuel tank 40 is sucked in. ing.

The relief passage 45 is connected to the fuel passage 43 and the fuel tank 40. The relief valve 46 is provided in the relief passage 45, and when the pressure (fuel pressure Pf) of the fuel in the fuel flow path 43 is less than the valve opening pressure Pfrv of the relief valve 46, the valve is closed and the fuel in the fuel flow path 43 is closed. When the pressure of the valve is equal to or higher than the valve opening pressure Pfrv, the valve is opened. When the relief valve 46 is opened, a part of the fuel in the fuel flow path 43 is returned to the fuel tank 40 via the relief passage 45. In this way, it is possible to prevent the fuel pressure in the fuel flow path 43 from becoming excessive.

The vaporized fuel processing device 50 is configured to be capable of executing purging to supply the vaporized fuel gas (purge gas) containing the vaporized fuel generated in the fuel tank 40 to the intake pipe 23. The vaporized fuel processing device 50 includes an introduction passage 51, a blockade valve 52, a canister 53, a purge passage 55, and a purge valve 56.

The introduction passage 51 is connected to the fuel tank 40 and the canister 53. The sealing valve 52 is provided in the introduction passage 51, and is configured as a normally closed type solenoid valve. The sealing valve 52 is controlled by an electronic control unit 70. The canister 53 is connected to the introduction passage 51 and the purge passage 55, and is open to the atmosphere through the atmosphere open passage 54. The inside of the canister 53 is filled with an adsorbent such as activated carbon capable of adsorbing the vaporized fuel from the fuel tank 40. An air filter (not shown) is provided in the air opening passage 54.

The purge passage 55 is connected to the canister 53 and the intake pipe 23 on the downstream side of the throttle valve 24. The purge valve 56 is provided in the purge passage 55 and is configured as a normally closed type solenoid valve. The purge valve 56 is controlled by the electronic control unit 70.

The vaporized fuel processing device 50 executes purging by adjusting the opening degree of the purge valve 56 when the sealing valve 52 is in the valve open state. Specifically, the flow rate of the vaporized fuel gas (purge gas) including the vaporized fuel generated in the fuel tank 40 is adjusted via the introduction passage 51, the canister 53, and the purge passage 55 by utilizing the negative pressure in the intake pipe 23. Is supplied to the intake pipe 23. Therefore, the engine 12 is capable of sucking a mixture of air and fuel (fuel from the fuel injection valve 26 and vaporized fuel from the vaporized fuel processing device 50) into the combustion chamber 29.

The electronic control unit 70 is configured as a microprocessor centered on a CPU, and in addition to the CPU, a ROM for storing a processing program, a RAM for temporarily storing data, a flash memory for storing and holding data, and an input device. It has an output port. Signals from various sensors are input to the electronic control unit 70 via the input port.

The signals input to the electronic control unit 70 include, for example, a crank angle θcr from the crank position sensor 14a that detects the rotational position of the crankshaft 14 of the engine 12, and a water temperature sensor 15 that detects the temperature of the cooling water of the engine 12. The cooling water temperature Tw can be mentioned. The throttle opening TH from the throttle position sensor 24a that detects the opening (position) of the throttle valve 24, the intake camshaft that opens and closes the intake valve 28, and the cam that detects the rotational position of the exhaust camshaft that opens and closes the exhaust valve 33. The cam angles θci and θco from the position sensor 16 can also be mentioned. The intake air amount Qa from the air flow meter 23a attached to the upstream side of the throttle valve 24 of the intake pipe 23, and the intake air temperature Ta from the temperature sensor 23b attached to the upstream side of the throttle valve 24 of the intake pipe 23. From the front air-fuel ratio AF1 from the front air-fuel ratio sensor 37 installed on the upstream side of the purification device 35 of the exhaust pipe 34, and from the rear air-fuel ratio sensor 38 installed on the downstream side of the purification device 35 of the exhaust pipe 34. The rear air-fuel ratio AF2 can also be mentioned. From the tank internal pressure Pt, which is the pressure inside the fuel tank 40 from the pressure sensor 40a attached to the fuel tank 40, or from the fuel pressure sensor 43p attached to the vicinity of the fuel injection valve 26 (for example, the delivery pipe) of the fuel flow path 43. The fuel pressure Pf, which is the pressure of the fuel in the fuel flow path 43, and the rotation speed Np of the fuel pump 44 from the rotation speed sensor 44b attached to the fuel pump 44 can also be mentioned. The opening Osv of the blocking valve 52 from the blocking valve position sensor 52a that detects the opening (position) of the blocking valve 52, and the opening of the purge valve 56 from the purge valve position sensor 56a that detects the opening (position) of the purge valve 56. Opv can also be mentioned. The ignition signal IG from the ignition switch 80 and the shift position SP from the shift position sensor 82 that detects the operation position of the shift lever 81 can also be mentioned. Accelerator opening Acc from the accelerator pedal position sensor 84 that detects the amount of depression of the accelerator pedal 83, brake pedal position BP from the brake pedal position sensor 86 that detects the amount of depression of the brake pedal 85, and vehicle speed V from the vehicle speed sensor 88. , The atmospheric pressure Pout from the atmospheric pressure sensor 89 can also be mentioned.

Various control signals are output from the electronic control unit 70 via the output port. The signals output from the electronic control unit 70 include, for example, a control signal to the throttle valve 24, a control signal to the fuel injection valve 26, a control signal to the ignition plug 30, a control signal to the fuel pump 44, and a block valve. A control signal to the 52 and a control signal to the purge valve 56 can be mentioned. Further, a control signal to the transmission 60 and a control signal to a starter (not shown) can also be mentioned.

The electronic control unit 70 calculates the rotation speed Ne of the engine 12 based on the crank angle θcr from the crank position sensor 14a. Further, the electronic control unit 70 has a load factor (air actually sucked in one cycle with respect to the stroke volume per cycle of the engine 12) based on the intake air amount Qa from the air flow meter 23a and the rotation speed Ne of the engine 12. Volume ratio of) KL is calculated. Further, the electronic control unit 70 calculates the consumption flow rate Qfr of the engine 12 based on the fuel injection amount Qf from the fuel injection valve 26.

In the automobile 10 of the embodiment configured in this way, the electronic control unit 70 controls the operation of the engine 12 based on the required load factor KL * of the engine 12 based on the accelerator opening Acc and the vehicle speed V, specifically, the throttle. Intake air amount control for controlling the opening degree of the valve 24, fuel injection control for controlling the fuel injection amount from the fuel injection valve 26, ignition control for controlling the ignition timing of the ignition plug 30, and the like are performed. Further, the electronic control unit 70 also controls the fuel pump 44 of the fuel supply device 42, the block valve 52 of the vaporized fuel processing device 50, the purge valve 56, and the like.

Further, in the automobile 10 of the embodiment, when the accelerator is released while the electronic control unit 70 is running, the fuel of the engine 12 is cut. Further, in the automobile 10 of the embodiment, the electronic control unit 70 intermittently stops the engine 12 when the intermittent stop condition is satisfied during the operation of the engine 12 while the vehicle is stopped, and the restart condition is set during the intermittent stop of the engine 12. When it is established, the engine 12 is cranked by the starter and the engine 12 is restarted. As the intermittent stop condition, for example, a condition that the accelerator is off and the brake is on is used. As the restart condition, for example, the condition that the accelerator is turned on or the brake is turned off is used.

In the operation control of the engine 12, in the intake air amount control, the electronic control unit 70 sets the target opening TH * of the throttle valve 24 based on the required load factor KL * of the engine 12, and sets the target opening TH *. Is used to control the throttle valve 24. In ignition control, the electronic control unit 70 sets the target ignition timing Ti * of the spark plug 30 based on the rotation speed Ne of the engine 12 and the load factor KL, and uses the set target ignition timing Ti * to set the spark plug 30. Control. In the control of the block valve 52, when the tank internal pressure Pt (gauge pressure) is equal to or lower than the threshold Ptref slightly higher than 0 kPa, the block valve 52 is controlled so as to be in a closed state, and when the tank internal pressure Pt is higher than the threshold Ptref. , The closure valve 52 is controlled so as to be in the valve open state. In the control of the purge valve 56, when the purge condition is satisfied, the purge valve 56 is controlled so that the valve is opened and the above-mentioned purge is executed, and when the purge condition is not satisfied, the purge valve 56 is closed. Control. As the purging condition, for example, a condition that the cooling water temperature Tw is equal to or higher than the threshold value, the operation control of the engine 12 (fuel injection control, etc.) is performed, and the closing valve 52 is in the open state is used. Hereinafter, fuel injection control, control of the fuel pump 44, and the like will be described.

Fuel injection control will be described. FIG. 2 is a flowchart showing an example of a fuel injection control routine executed by the electronic control unit 70. This routine is repeatedly executed when fuel injection control is performed. When this routine is executed, the electronic control unit 70 first inputs data such as the intake air amount Qa, the front air-fuel ratio AF1, the load factor KL, and the purge concentration related value Cpg (step S100). Here, a value detected by the air flow meter 23a is input as the intake air amount Qa. The value detected by the front air-fuel ratio sensor 37 is input to the front air-fuel ratio AF1. As the load factor KL, a value calculated based on the intake air amount Qa and the rotation speed Ne as described above is input.

The purge concentration-related value Cpg is related to the deviation amount of the front air-fuel ratio AF1 with respect to the required air-fuel ratio AF * (for example, the theoretical air-fuel ratio) per 1% of the purge rate (ratio of vaporized fuel gas (purge gas) to intake air amount). It is a value to be used. When the value is negative, the purge concentration-related value Cpg means that the gas supplied from the vaporized fuel processing device 50 to the combustion chamber 29 via the intake pipe 23 contains the vaporized fuel, and the value is 0 or more. When, it means that this gas does not contain vaporized fuel. Further, the purge concentration-related value Cpg becomes smaller as the purge concentration (concentration of the vaporized fuel in the vaporized fuel gas when the purge is executed) becomes darker (the absolute value becomes larger in the negative range). Further, as the purge concentration-related value Cpg, a value set by the purge concentration-related value setting routine described later executed by the electronic control unit 70 is input.

When the data is input in this way, the base injection amount Qfbs of the fuel injection valve 26 is set based on the load factor KL of the engine 12 (step S110). Here, the base injection amount Qfbs is a base value of the target injection amount Qf * of the fuel injection valve 26 for setting the front air-fuel ratio AF1 to the required air-fuel ratio AF *. The base injection amount Qfbs can be calculated, for example, as a value obtained by multiplying the unit injection amount (fuel injection amount per 1% of the load factor KL) Qfpu by the load factor KL.

Subsequently, the purge correction coefficient Kpg is set based on the purge concentration-related value Cpg (step S120), and the value obtained by multiplying the base injection amount Qfbs by the purge correction coefficient Kpg is set as the target injection amount Qf * (step S130). Then, the fuel injection valve 26 is controlled using the set target injection amount Qf * (step S140), and this routine is terminated. Here, the purge correction coefficient Kpg can be set, for example, by applying the purge concentration-related value Cpg to the map for setting the purge correction coefficient. The purge correction coefficient setting map is predetermined as the relationship between the purge concentration-related value Cpg and the purge correction coefficient Kpg, and is stored in the ROM or flash memory of the electronic control unit 70. The purge correction coefficient Kpg is set so as to be smaller with respect to the value 1 as the purge concentration-related value Cpg is smaller (the absolute value is larger in the negative range), that is, the higher the purge concentration is. Therefore, the fuel injection valve 26 is controlled by setting the target injection amount Qf * so that the higher the purge concentration, the smaller the amount.

Next, the setting process of the purge concentration-related value Cpg used in the fuel injection control routine of FIG. 2 and the like will be described. FIG. 3 is a flowchart showing an example of a purge concentration-related value setting routine executed by the electronic control unit 70. This routine is executed repeatedly. For the purge concentration-related value Cpg and the purge concentration learning frequency Npg described later, for example, a value 0 as an initial value is set at the start of the trip.

When the purge concentration-related value setting routine of FIG. 3 is executed, the electronic control unit 70 first inputs data such as the front air-fuel ratio AF1 and the purge execution flag Fpg (step S200). Here, the value detected by the front air-fuel ratio sensor 37 is input to the front air-fuel ratio AF1.

The purge execution flag Fpg is a flag in which a value 1 is set when purging is being executed, and a value 0 is set when purging is not being executed. For the purge execution flag Fpg, a value set by a purge execution flag setting routine (not shown) executed by the electronic control unit 70 is input. In the purge execution flag setting routine, the electronic control unit 70 determines whether or not the purge is executed based on the opening degree Osv of the blocking valve 52 and the opening degree Opv of the purge valve 56.

When the data is input in this way, the value of the purge execution flag Fpg is checked (step S210). When the purge execution flag Fpg has a value of 0 (purge is not executed), the purge concentration-related value Cpg is held (step S220), the purge concentration learning count Npg is held (step S230), and this routine is executed. finish.

When the purge execution flag Fpg is a value 1 (purge is being executed) in step S210, the update amount ΔCpg of the purge concentration related value Cpg is set based on the front air fuel ratio AF1 (step S240), and the purge concentration related value is set. By setting the value obtained by adding the update amount ΔCpg to the previous value of Cpg to the new purge concentration-related value Cpg, the purge concentration-related value Cpg is updated (learned) (step S250), and the purge concentration learning frequency Npg is set to the value 1. Only count up (step S260), and this routine ends.

Here, the update amount ΔCpg can be set by applying, for example, the front air-fuel ratio AF1 to the update amount setting map. The update amount setting map is predetermined as the relationship between the front air-fuel ratio AF1 and the update amount ΔCpg, and is stored in the ROM or the flash memory of the electronic control unit 70. FIG. 4 is an explanatory diagram showing an example of an update amount setting map. As shown in the figure, the update amount ΔCpg is set to a value of 0 when the front air-fuel ratio AF1 is equal to the required air-fuel ratio AF *. Further, the update amount ΔCpg is set so that when the front air-fuel ratio AF1 is larger than the required air-fuel ratio AF * (when it is on the lean side), the larger the front air-fuel ratio AF1 is, the larger it is within the positive range. To. Further, when the front air-fuel ratio AF1 is smaller than the required air-fuel ratio AF * (when it is on the rich side), the update amount ΔCpg becomes smaller in the negative range as the front air-fuel ratio AF1 is smaller (the absolute value becomes smaller). It is set to increase). Basically, the higher the purge concentration, the more fuel in the combustion chamber 29 tends to be, and the front air-fuel ratio AF1 tends to be smaller than the required air-fuel ratio AF *. Therefore, the higher the purge concentration, the smaller the renewal amount ΔCpg and thus the purge concentration-related value Cpg (the absolute value tends to increase within the negative range).

Next, the control of the fuel pump 44 of the fuel supply device 42 will be described. 5 to 7 are flowcharts showing an example of a fuel pump control routine executed by the electronic control unit 70. This routine is executed repeatedly. When this routine is executed, the electronic control unit 70 first inputs data such as fuel pressure Pf, load factor KL, engine rotation flag Fer, fuel cut flag Ffc1, and fuel boiling detection flag Fv (step S300). Here, a value detected by the fuel pressure sensor 43p is input as the fuel pressure Pf. As the load factor KL, a value calculated based on the intake air amount Qa and the rotation speed Ne as described above is input.

The engine rotation flag Ferr is a flag in which a value 1 is set when the engine 12 is in the rotation state, and a value 0 is set when the engine 12 is in the rotation stop state. A value set by an engine rotation flag setting routine (not shown) executed by the electronic control unit 70 is input to the engine rotation flag Ferr. In the engine rotation flag setting routine, the electronic control unit 70 determines whether the engine 12 is in the rotation state or the rotation stop state based on the rotation speed Ne of the engine 12.

The fuel cut flag Ffc1 is a flag in which a value 1 is set when the fuel of the engine 12 is being cut, and a value 0 is set when the fuel of the engine 12 is not being cut (fuel injection control or the like is being performed). be. For the fuel cut flag Ffc1, a value set by a fuel cut flag setting routine (not shown) executed by the electronic control unit 70 is input.

The fuel boiling detection flag Fv is set to a value of 1 when the boiling of the fuel in the fuel tank 40 is detected, and when the boiling of the fuel in the fuel tank 40 is not detected (when the detection is reset to undetected). Is a flag for which a value of 0 is set. For the fuel boiling detection flag Fv, a value set by a fuel boiling detection flag setting routine described later executed by the electronic control unit 70 is input. Since the fuel in the fuel tank 40 boils when the absolute pressure in the fuel tank 40 is equal to or lower than the saturated vapor pressure of the fuel, the fuel in the fuel tank 40 has a high altitude and a low atmospheric pressure Pout. , When the temperature of the fuel in the fuel tank 40 is high and the saturated vapor pressure of the fuel is high, it tends to boil.

When the data is input in this way, the value of the engine rotation flag Ferr is checked (step S310). When the engine rotation flag Fer has a value of 1 (the engine 12 is in the rotation state), the value of the fuel boiling detection flag Fv is checked (step S320). When the fuel boiling detection flag Fv has a value of 0 (the boiling of the fuel in the fuel tank 40 has not been detected), the target is within the range of less than the valve opening pressure Pfrv of the relief valve 46 based on the state of the engine 12 and the like. The fuel pressure Pf * is set (step S330). The target fuel pressure Pf * may be used not only for the control of the fuel pump 44 but also for the operation control of the engine 12.

Subsequently, the value of the fuel cut flag Ffc1 is examined (step S340). When the fuel cut flag Ffc1 has a value of 0 (the fuel of the engine 12 is not cut), the feed forward term αf and the proportional term of the feedback term used for setting the target discharge flow rate Qp * of the fuel pump 44 by the fuel pressure feedback control. And the feedback proportional term αbp and the feedback integral term αbi, which are integration terms, are set (steps S350 to S354).

First, the feed forward term αf is set based on the load factor KL (step S350). Here, the feed forward term αf can be set, for example, by applying the load factor KL to the feed forward term setting map. The map for setting the feedforward term is predetermined as the relationship between the load factor KL and the feedforward term αf, and is stored in the ROM or the flash memory of the electronic control unit 70. FIG. 8 is an explanatory diagram showing an example of a map for setting a feed forward term. As shown in the figure, the feed forward term αf is set so as to increase as the load factor KL increases. Subsequently, as shown in the equation (1), the product of the value obtained by subtracting the fuel pressure Pf from the target fuel pressure Pf * and the gain Kp of the proportional term is set in the feedback proportional term αbp (step S352). Then, as shown in the equation (2), the sum of the previous value of the feedback integral term αbi, the product of the value obtained by subtracting the fuel pressure Pf from the target fuel pressure Pf * and the gain Ki of the integral term is a new feedback integral term. The feedback integral term αbi is updated by setting it to αbi (step S354).

αbp ＝ Kp ・ (Pf * －Pf) (1)
αbi ＝ Last time αbi + Ki ・ (Pf * －Pf) (2)

When the fuel cut flag Ffc1 has a value of 1 (fuel cut of the engine 12 is performed) in step S340, the value 0 is set in the feedback term αf (step S360), and the equation (1) is the same as in the process of step S352. ) Set the feedback proportional term αbp (step S362), and hold the feedback integral term αbi at the previous value (step S364).

When the feedforward term αf, the feedback proportional term αbp, and the feedback integral term αbi are set in this way, a value obtained by guarding the sum of these at the lower limit with a value of 0 is set as the target discharge flow rate Qp * of the fuel pump 44 (step S370). Subsequently, the target rotation speed Np * of the fuel pump 44 is set based on the set target discharge flow rate Qp * (step S372), and the fuel pump 44 is controlled using the set target rotation speed Np * (step S374). ), End this routine.

In this case, the target rotation speed Np * can be set by applying, for example, the target discharge flow rate Qp * to the target rotation speed setting map. The target rotation speed setting map is predetermined as the relationship between the target discharge flow rate Qp * and the target rotation speed Np *, and is stored in the ROM or flash memory of the electronic control unit 70. FIG. 9 is an explanatory diagram showing an example of a map for setting a target rotation speed. As shown in the figure, the target rotation speed Np * is set so as to increase as the target discharge flow rate Qp * increases. Hereinafter, the control of the fuel pump 44 (steps S330 to S374) when the engine rotation flag Ferr is a value 1 and the fuel boiling detection flag Fv is a value 0 is referred to as "normal pump control".

When the fuel boiling detection flag Fv is a value 1 (detecting the boiling of the fuel in the fuel tank 40) in step S320, the valve opening pressure Pfrv of the relief valve 46 is set to the target fuel pressure Pf * (step S380). , Check the value of the fuel cut flag Ffc1 (step S390). When the fuel cut flag Ffc1 has a value of 0 (the fuel of the engine 12 is not cut), the feed forward term αf is set in the same manner as in the process of step S350 described above (step S392). When the fuel cut flag Ffc1 has a value of 1 (fuel cut of the engine 12 is being performed), the value 0 is set in the feed forward term αf (step S394).

When the feed forward term αf is set in this way, the set feed forward term αf is set to the target discharge flow rate Qp * of the fuel pump 44 (step S400), and the set target discharge flow rate Qp * is set in the same manner as in the process of step S372 described above. The provisional rotation speed Nptmp, which is a provisional value of the target rotation speed Np * of the fuel pump 44, is set based on the above (step S402). For the temporary rotation speed Nptmp in this case, for example, the target discharge flow rate Qp * is applied to the map in which the vertical axis of the target rotation speed setting map in FIG. 9 is replaced from "target rotation speed Np *" to "temporary rotation speed Nptmp". Can be set.

Subsequently, as shown in the equation (3), the value obtained by guarding the upper and lower limits of the set temporary rotation speed Nptmp of the fuel pump 44 with the lower limit rotation speed Npmin and the upper limit rotation speed Npmax is set as the target rotation speed Np * of the fuel pump 44. (Step S404). Then, the fuel pump 44 is controlled using the set target rotation speed Np * (step S406). Here, the details of the lower limit rotation speed Npmin and the upper limit rotation speed Npmax will be described later. Hereinafter, the control of the fuel pump 44 (steps S380 to S406) when the engine rotation flag Ferr is a value 1 and the fuel boiling detection flag Fv is a value 1 is referred to as "boiling pump control".

Np * ＝ min (max (Nptmp, Npmin), Npmax) (3)

When the fuel in the fuel tank 40 is boiling, the fuel pump 44 may suck in vaporized fuel (fuel vaporized by evaporation or boiling, mainly the latter), and the discharge pressure of the fuel pump 44 may decrease. Alternatively, the discharge pressure of the fuel pump 44 has already dropped. When the discharge pressure of the fuel pump 44 decreases, the fuel pressure Pf decreases, which in turn leads to a decrease in the fuel injection amount from the fuel injection valve 26 (decrease in controllability of fuel injection control). Therefore, it is required to suppress the decrease in the discharge pressure of the fuel pump 44, or to eliminate the decrease when the discharge pressure has already decreased.

Based on this, in the embodiment, when the fuel boiling detection flag Fv has a value of 1 (the boiling of the fuel in the fuel tank 40 is detected), the pump control at the time of boiling is executed. Specifically, the fuel pump 44 is controlled by setting the temporary rotation speed Nptmp of the fuel pump 44 to the target rotation speed Np * with the upper and lower limit guarded values of the lower limit rotation speed Npmin and the upper limit rotation speed Npmax. The lower limit rotation speed Npmin is the lower limit value of the rotation speed range of the fuel pump 44 that can sufficiently discharge the vaporized fuel from the discharge hole 44a when the fuel pump 44 sucks in the vaporized fuel (mainly the fuel vaporized by boiling). Is used. As the upper limit rotation speed Npmax, the upper limit value of the rotation speed range of the fuel pump 44 capable of sufficiently suppressing the generation of vaporized fuel in the fuel pump 44 due to the calorific value of the fuel pump 44 is used.

When the fuel in the fuel tank 40 is boiling, when the load factor KL is low, or when the fuel is cut, the feed forward term αf becomes small and the temporary rotation speed Nptmp of the fuel pump 44 becomes small (step). S390-S402). In the embodiment, the fuel pump 44 sucks the vaporized fuel (mainly the fuel vaporized by boiling) by setting the value obtained by guarding the temporary rotation speed Nptmp of the fuel pump 44 at the lower limit rotation speed Npmin to the target rotation speed Np *. When it is pumped, the vaporized fuel can be sufficiently discharged from the discharge hole 44a. As a result, it is possible to suppress the decrease in the discharge pressure of the fuel pump 44, or to eliminate the decrease when it has already decreased.

Further, when the fuel in the fuel tank 40 is boiling, if the rotation speed Np of the fuel pump 44 is set too high, vaporized fuel may be generated in the fuel pump 44 due to the calorific value thereof. .. In the embodiment, by setting a value obtained by guarding the temporary rotation speed Nptmp of the fuel pump 44 at the upper limit rotation speed Npmax to the target rotation speed Np *, vaporization in the fuel pump 44 due to the calorific value of the fuel pump 44 is set. The generation of fuel can be sufficiently suppressed.

When the pump control during boiling is executed in this way (steps S380 to S406), the integrated execution time Tfup of the pump control during boiling is timed (step S408), and the feedback integral term αbi is held at the previous value (step S410). , End this routine. Here, the integrated execution time Tfup is set to a value of 0 as an initial value at the time of shipment or maintenance of the automobile 10, for example. In the embodiment, the integrated execution time Tfup is stored in the RAM or flash memory of the electronic control unit 70, or transmitted to the manufacturer, the dealer, or the like. As a result, various analyzes and the like can be performed by the manufacturer, the dealer, and the like using the integrated execution time Tfup.

When the engine rotation flag Fer has a value of 0 in step S310 (the engine 12 is in a rotation stopped state), values 0 are set for the target fuel pressure Pf *, the target discharge flow rate Qp *, and the target rotation speed Np * (step S420). ~ S424), the fuel pump 44 is controlled using the set target rotation speed Np * (step S426). Then, the feedback integral term αbi is held at the previous value (step S428), and this routine is terminated. In this case, the fuel pump 44 is put into the rotation stop state (from the rotation state to the rotation stop state or the rotation stop state is maintained). As described above, when the engine 12 is in the stopped rotation state, regardless of the value of the fuel boiling detection flag Fv (regardless of whether the boiling of the fuel in the fuel tank 40 is not detected or detected). The fuel pump 44 is stopped rotating. As a result, it is possible to suppress the noise and vibration generated by the driving of the fuel pump 44 from being perceived by the occupants (including the driver).

Next, the setting process of the fuel boiling detection flag Fv used in the fuel pump control routines of FIGS. 5 to 7 and the setting process of the fuel pressure convergence detection flag Fpc used in the setting process of the fuel boiling detection flag Fv will be described. Here, the fuel pressure convergence detection flag Fpc is set to a value 1 when the fuel pressure Pfcn, which is the pulsating center of the fuel pressure Pf, detects the convergent fuel pressure convergence near the target fuel pressure Pf *, and the fuel pressure convergence is not detected. It is a flag in which a value 0 is set (including when resetting from detection to non-detection). A value set by the fuel pressure convergence detection flag setting routine executed by the electronic control unit 70 is input to the fuel pressure convergence detection flag Fpc. The fuel boiling detection flag Fv and the fuel pressure convergence detection flag Fpc are set to, for example, a value 0 as an initial value at the start of the trip.

10 to 12 are flowcharts showing an example of a fuel boiling detection flag setting routine executed by the electronic control unit 70, and FIG. 13 is an example of a fuel pressure convergence detection flag setting routine executed by the electronic control unit 70. It is a flowchart which shows. Each of these routines is executed repeatedly. Hereinafter, for the sake of simplicity, the fuel pressure convergence detection flag setting routine of FIG. 13 will be described, and then the fuel boiling detection flag setting routine of FIGS. 10 to 12 will be described.

The fuel pressure convergence detection flag setting routine of FIG. 13 will be described. When this routine is executed, the electronic control unit 70 first inputs data such as a fuel pressure Pf, a target fuel pressure Pf *, a fuel pump rotation flag Fpr, and a fuel cut continuation flag Ffc2 (step S700). Here, a value detected by the fuel pressure sensor 43p is input as the fuel pressure Pf. As the target fuel pressure Pf *, a value set by the fuel pump control routine of FIGS. 5 to 7 is input.

The fuel pump rotation flag Fpr is a flag in which a value 1 is set when the fuel pump 44 is in the rotating state, and a value 0 is set when the fuel pump 44 is in the rotating stopped state. For the fuel pump rotation flag Fpr, a value set by a fuel pump rotation flag setting routine (not shown) executed by the electronic control unit 70 is input. In the fuel pump rotation flag setting routine, the electronic control unit 70 determines whether the fuel pump 44 is in the rotating state or the rotating stopped state based on the rotation speed Np of the fuel pump 44.

The fuel cut continuation flag Ffc2 is set to a value 1 when the condition that the fuel of the engine 12 is cut and the duration is Ffc or more for a predetermined time is satisfied, and the value is 0 when this condition is not satisfied. Is a flag to be set. For the fuel cut continuation flag Ffc2, a value set by a fuel cut continuation flag setting routine (not shown) executed by the electronic control unit 70 is input. As the predetermined time Ffc, a time during which the reliability of the feedback integral term αbi cannot be guaranteed, for example, about several hundred to several thousand msec is used.

When the data is input in this way, the value of the fuel pump rotation flag Fpr is checked (step S710), the target fuel pressure Pf * is compared with the valve opening pressure Pfrv of the relief valve 46 (step S712), and the value of the fuel cut continuation flag Ffc2 is checked. (Step S714). As described in the fuel pump control routines of FIGS. 5 to 7, when the fuel pump 44 is in the rotation stopped state, when the target fuel pressure Pf * is equal to the valve opening pressure Pfrv, and when the fuel is cut, feedback is performed. Holds the integral term αbi. Therefore, the reliability of the feedback integral term αbi is lowered. The processes of steps S710 to S714 are processes for determining whether or not the fuel pressure convergence is undetected (held undetected or reset from detected to undetected) based on these.

When the fuel pump rotation flag Fpr is 0 (the fuel pump 44 is in the rotation stopped state) in step S710, or when the target fuel pressure Pf * is equal to the valve opening pressure Pfrv of the relief valve 46 in step S712, in step S714. When the fuel cut continuation flag Ffc2 has a value of 1 (fuel cut is performed and the duration is Ffc or more for a predetermined time), it is determined that the fuel pressure convergence is not detected, and the value 0 is set to the fuel pressure convergence detection flag Fpc. The setting (step S716) is performed, and this routine is terminated.

In step S710, the fuel pump rotation flag Fpr has a value of 1 (the fuel pump 44 is in the rotating state), and in step S712, the target fuel pressure Pf * is less than the valve opening pressure Pfrv of the relief valve 46, and in step S714. When the fuel cut continuation flag Ffc2 has a value of 0 (fuel cut is not performed or the fuel cut duration is less than Ffc for a predetermined time), the fuel pressure Pf is adjusted without determining that the fuel pressure convergence is not detected. The value obtained by the treatment is estimated as the pulsation center fuel pressure Pfcn (step S720). When the operation of the engine 12 is controlled, the fuel pressure Pf pulsates due to the influence of fuel injection from the fuel injection valve 26 and the like. The process of step S720 is a process of estimating the pulsation center of the fuel pressure Pf.

Subsequently, the absolute value of the value obtained by subtracting the pulsation center fuel pressure Pfcn from the target fuel pressure Pf * is set in the fuel pressure difference ΔPf (step S730), and the fuel pressure difference ΔPf is equal to or less than the threshold value ΔPref and its duration is Tpf or more for a predetermined time. It is determined whether or not a certain condition is satisfied (steps S740 and S742). Here, the threshold value ΔPref is used to determine whether or not the fuel pressure difference ΔPf is sufficiently small. The predetermined time Tpf is used for the time required to determine that the fuel pressure difference ΔPf is stable below the threshold value ΔPref (the pulsating center fuel pressure Pfcn converges near the target fuel pressure Pf *), for example, about several hundred msec. Be done. The process of steps S740 and S742 is a process of determining whether or not the fuel pressure convergence is to be detected (changed from undetected to detected or held by detection).

In steps S740 and S742, when the condition that the fuel pressure difference ΔPf is equal to or less than the threshold value ΔPref and the duration thereof is Tpf or more for a predetermined time is satisfied, it is determined that the fuel pressure convergence is detected, and the fuel pressure convergence detection flag Fpc is set to a value. 1 is set (step S744), and this routine ends. As described above, when the operation of the engine 12 is controlled, the fuel pressure Pf pulsates due to the influence of fuel injection from the fuel injection valve 26 and the like. Therefore, by setting the absolute value of the value obtained by subtracting the pulsation center fuel pressure Pfcn from the target fuel pressure Pf * to the fuel pressure difference ΔPf, the absolute value of the value obtained by subtracting the fuel pressure Pf from the target fuel pressure Pf * is set to the fuel pressure difference ΔPf. It is possible to make it easier to detect the convergence of fuel pressure as compared with the one. When the fuel pressure Pf and the pulsation center fuel pressure Pfcn converge near the target fuel pressure Pf *, the engine rotation flag Ferr is a value 1 and the fuel boiling detection flag Fv is set in the fuel pump control routines of FIGS. 5 to 7. It is assumed that the feedback integral term αbi, which is sequentially updated when the value is 0 and the fuel cut flag Ffc1 is the value 1, is also stable.

In steps S740 and S742, when the condition that the fuel pressure difference ΔPf is equal to or less than the threshold value ΔPref and the duration thereof is Tpf or more for a predetermined time is not satisfied, the fuel pressure convergence detection flag Fpc is set without determining that the fuel pressure is detected. The previous value is held (step S746), and this routine is terminated.

In the embodiment, when the fuel pump rotation flag Fpr has a value of 0 (the fuel pump 44 is in the rotation stopped state) or when the target fuel pressure Pf * is equal to the valve opening pressure Pfrv of the relief valve 46, the fuel cut continuation flag Ffc2 Is a value of 1 (fuel cut is performed and its duration is Ffc or more for a predetermined time), a value of 0 is set in the fuel pressure convergence detection flag Fpc (fuel pressure convergence is not detected). .. Therefore, when the fuel pressure convergence detection flag Fpc has a value of 1, the fuel boiling detection flag Fv is switched to switch the target fuel pressure Pf *, or the fuel cut duration is less than the predetermined time Tfc. The fuel pressure convergence detection flag Fpc is held at a value of 1.

Next, the fuel boiling detection flag setting routine of FIGS. 10 to 12 will be described. When this routine is executed, the electronic control unit 70 first receives the cooling water temperature Tw, the intake air temperature Ta, the tank internal pressure Pt, the purge concentration related value Cpg, the purge concentration learning frequency Npg, the feedback integration term αbi, and the integration term update continuation. Data such as the flag Fiu, the consumption flow rate stabilization flag Ffr, and the fuel pressure convergence detection flag Fpc are input (step S500).

Here, a value detected by the water temperature sensor 15 is input as the cooling water temperature Tw. The value detected by the temperature sensor 23b is input to the intake air temperature Ta. The value detected by the pressure sensor 40a is input to the tank internal pressure Pt. As the purge concentration-related value Cpg and the purge concentration learning frequency Npg, the values set by the purge concentration-related value setting routine of FIG. 3 are input. The value set by the fuel pump control routine of FIGS. 5 to 7 is input to the feedback integration term αbi.

The integral term update continuation flag Fiu is set to a value 1 when the condition that the feedback integral term αbi is updated and the update continuation time is Tiu or more for a predetermined time is satisfied, and when this condition is not satisfied, the value 1 is set. A flag for which a value of 0 is set. The value set by the integral term update continuation flag setting routine (not shown) executed by the electronic control unit 70 is input to the integral term update continuation flag Fiu. As the predetermined time Tiu, a time during which the reliability of the feedback integration term αbi can be ensured, for example, about several hundred to several thousand msec is used.

The consumption flow rate stabilization flag Ffr is a flag in which a value 1 is set when the fuel consumption flow rate Qfr of the engine 12 is stable, and a value 0 is set when the fuel consumption flow rate Qfr of the engine 12 is not stable. .. A value set by a consumption flow rate stabilization flag setting routine (not shown) executed by the electronic control unit 70 is input to the consumption flow rate stabilization flag Ffr. In the consumption flow rate stabilization flag setting routine, the electronic control unit 70 has the consumption flow rate fluctuation amount ΔQfr (difference between the maximum value and the minimum value), which is the fluctuation amount of the consumption flow rate Qfr per unit time, equal to or less than the threshold value ΔQfrref and its continuation. When the condition that the time is Tfr or more for a predetermined time is satisfied, it is determined that the fuel consumption flow rate Qfr of the engine 12 is stable, and when this condition is not satisfied, the fuel consumption flow rate Qfr of the engine 12 is determined. Is not stable. The consumption flow rate Qfr is calculated based on the fuel injection amount Qf from the fuel injection valve 26. The threshold value ΔQfcref is used to determine whether or not the consumption flow rate fluctuation amount ΔQfr is sufficiently small. As the predetermined time Tfr, the time required to determine that the consumption flow rate fluctuation amount ΔQfr is stable below the threshold value ΔQfrref, for example, about several hundred to several thousand msec is used.

When the data is input in this way, the value obtained by subjecting the feedback integral term αbi to the high response smoothing process is set to the high response process value βhi (step S510), and the feedback integral term αbi is subjected to the low response smoothing process. The value obtained by performing the processing is set to the low response processing value βlo (step S512). Here, the highly responsive tanning process is a tanning process using a predetermined number of times Nsm1 (for example, about several times) as the number of tanning times Nsm, and the low responsiveness tanning process is a tanning process using the predetermined number of times Nsm. This is an annealing process using a predetermined number of times Nsm2 (for example, about several thousand times) larger than a predetermined number of times Nsm1.

Subsequently, it is determined whether or not the fuel pressure convergence detection flag Fpc has just been switched from the value 0 to the value 1 (step S514). Immediately after the fuel pressure convergence detection flag Fpc is switched from the value 0 to the value 1 (immediately after the fuel pressure convergence is changed from undetected to detected), the high response processing value βhi is set to the convergence processing value βhi0 (step). S516). When the fuel pressure convergence detection flag Fpc is not immediately after switching from the value 0 to the value 1 (not immediately after the fuel pressure convergence is changed from undetected to detected), the process of step S516 is not executed. In the embodiment, the convergence processing value βhi0 is reset when the fuel pressure convergence detection flag Fpc is switched from the value 1 to the value 0.

Then, the purge concentration learning frequency Npg is compared with the threshold value Npgref (step S520), the purge concentration-related value Cpg is compared with the threshold value Cpgref1 (step S522), and the tank internal pressure Pt is compared with the threshold value Ptref2 (step S524). Here, the threshold value Npgref is used to determine whether or not the reliability of the purge concentration-related value Cpg can be guaranteed. The threshold Cpgref1 is used to determine whether the purge concentration-related value Cpg is relatively large, that is, whether the purge concentration is relatively low. The threshold value Ptref is used to determine whether or not the tank internal pressure Pt is about 0 kPa. When the fuel in the fuel tank 40 is boiling, more vaporized fuel is generated in the fuel tank 40 than when it is not boiling, and the tank internal pressure Pt tends to be high. Further, it is assumed that the smaller the purge concentration-related value Cpg (the larger the absolute value in the negative range), that is, the higher the purge concentration, the more vaporized fuel is generated in the fuel tank 40. Based on these, the processing of steps S520 to S524 makes the boiling of the fuel in the fuel tank 40 undetected (retained without detection) by using the purge concentration learning frequency Npg, the purge concentration related value Cpg, and the tank internal pressure Pt. It is a process of determining whether or not to perform or reset from detection to undetected).

When the purge concentration learning frequency Npg is equal to or greater than the threshold value Npgref in step S520, the purge concentration-related value Cpg is equal to or greater than the threshold value Cpgref1 in step S522, and the tank internal pressure Pt is less than the threshold value Ptref in step S524, the purge concentration learning frequency Npg is determined. It is determined that the boiling of the fuel in the fuel tank 40 is not detected based on the conditions of the purge concentration-related value Cpg and the tank internal pressure Pt, and the temporary undetected flag Fv1a is set to the value 1 (step S526).

Purge concentration learning when the number of times Npg of purge concentration learning is less than the threshold value Npgref in step S520, when the purge concentration-related value Cpg is less than the threshold value Cpgref1 in step S522, and when the tank internal pressure Pt is equal to or more than the threshold value Ptref1 in step S524. Under the conditions of the number of times Npg, the purge concentration-related value Cpg, and the tank internal pressure Pt, the value 0 is set in the provisional undetected flag Fv1a without determining that the boiling of the fuel in the fuel tank 40 is not detected (step S528).

Further, the cooling water temperature Tw is compared with the threshold value Twref (step S530). Here, the threshold value Twref is used to determine whether or not the cooling water temperature Tw is relatively low. Generally, when the cooling water temperature Tw is low, the temperature of the fuel in the fuel tank 40 is also low, and it is assumed that the fuel in the fuel tank 40 is unlikely to boil. Based on this, the process of step S530 is a process of determining whether or not boiling of the fuel in the fuel tank 40 is not detected by using the cooling water temperature Tw.

When the cooling water temperature Tw is less than the threshold value Twref in step S530, it is determined that boiling of the fuel in the fuel tank 40 is not detected due to the condition of the cooling water temperature Tw, and the value 1 is set in the provisional undetected flag Fv1b (step S532). ). When the cooling water temperature Tw is equal to or higher than the threshold value Tw, a value 0 is set in the provisional undetected flag Fv1b without determining that boiling of the fuel in the fuel tank 40 is not detected under the condition of the cooling water temperature Tw (step S534). ..

Further, the intake air temperature Ta is compared with the threshold value Taref (step S540). Here, the threshold value Taref is used to determine whether or not the intake air temperature Ta is relatively low. Generally, when the intake air temperature Ta is low, the temperature of the fuel in the fuel tank 40 is also low, and it is assumed that the fuel in the fuel tank 40 is unlikely to boil. Based on this, the process of step S540 is a process of determining whether or not the boiling of the fuel in the fuel tank 40 is not detected by using the intake air temperature Ta.

When the intake air temperature Ta is less than the threshold value Taref in step S540, it is determined that boiling of the fuel in the fuel tank 40 is not detected due to the condition of the intake air temperature Ta, and a value 1 is set in the provisional undetected flag Fv1c (step S542). ). When the intake air temperature Ta is equal to or higher than the threshold value Taref, the temporary undetected flag Fv1c is set to a value 0 without determining that boiling of the fuel in the fuel tank 40 is not detected under the condition of the intake air temperature Ta (step S544). ..

When the provisional undetected flags Fv1a, Fv1b, and Fv1c are set in this way, the values of the set provisional undetected flags Fv1a, Fv1b, and Fv1c are checked (steps S550 to S554). When at least one of the provisional undetected flags Fv1a, Fv1b, and Fv1c has a value of 1, the fuel boiling detection flag Fv is set to a value of 0 (step S556), and this routine is terminated. That is, at least one of the conditions of the purge concentration learning frequency Npg, the purge concentration-related value Cpg, and the tank internal pressure Pt (steps S520 to S524), the cooling water temperature Tw condition (step S530), and the intake air temperature Ta condition (step S540). When it is determined that the boiling of the fuel in the fuel tank 40 is not detected under one condition, the value 0 is set in the fuel boiling detection flag Fv1. In this way, boiling of fuel in the fuel tank 40 can be undetected (held undetected or reset from detected to undetected).

When all of the provisional undetected flags Fv1a, Fv1b, and Fv1c have a value of 0 in steps S550 to S554, the process proceeds to step S560. That is, any of the conditions of the purge concentration learning frequency Npg, the purge concentration-related value Cpg, and the tank internal pressure Pt (steps S520 to S524), the cooling water temperature Tw condition (step S530), and the intake air temperature Ta condition (step S540). If it is not determined that the boiling of the fuel in the fuel tank 40 is not detected even under the condition of, the process proceeds to step S560.

Subsequently, the purge concentration-related value Cpg is compared with the threshold value Cpgref2 which is equal to or less than the threshold value Cpgref1 described above (step S560). Here, the threshold value Cpgref2 is used to determine whether or not the purge concentration-related value Cpg is relatively small (the absolute value is large within the negative range), that is, whether the purge concentration is relatively high. As described above, when the fuel in the fuel tank 40 is boiling, more vaporized fuel is generated in the fuel tank 40 than when it is not boiling. Further, it is assumed that the smaller the purge concentration-related value Cpg (the larger the absolute value in the negative range), that is, the higher the purge concentration, the more vaporized fuel is generated in the fuel tank 40. Based on this, the process of step S560 is a process of determining whether or not to detect the boiling of the fuel in the fuel tank 40 by using the purge concentration learning frequency Npg.

When the purge concentration-related value Cpg is less than the threshold value Cpgref2 in step S560, it is determined that boiling of the fuel in the fuel tank 40 is detected according to the condition of the purge concentration-related value Cpg, and the temporary detection flag Fv2a is set to the value 1. Step S562). When the purge concentration-related value Cpg is equal to or higher than the threshold value Cpgref2, the provisional detection flag Fv2a is set to a value 0 without determining that boiling of the fuel in the fuel tank 40 is detected under the condition of the purge concentration-related value Cpg (step). S564). In order to suppress erroneous determination, the provisional detection flag Fv2a may be set to a value 1 when the purge concentration-related value Cpg is less than the threshold value Cpgref2 and the duration thereof is Tpg or more for a predetermined time. As the predetermined time Tpg, the time required to determine that the purge concentration-related value Cpg is less than the threshold value Cpgref2, for example, about several hundred msec is used. Further, in consideration of the reliability of the purge concentration-related value Cpg, the temporary detection flag Fv2a is set to the value 1 when the purge concentration-related value Cpg is less than the threshold value Cpgref2 and the purge concentration learning frequency Npg is equal to or more than the threshold value Npgref. It may be the one to do.

Subsequently, the values of the fuel pressure convergence detection flag Fpc, the integral term update continuation flag Fiu, and the consumption flow rate stabilization flag Ffr are examined (steps S570 to S574). The process of steps S570 to S574 is a process of determining whether or not the feedback integral term αbi is reliable. When the fuel pressure convergence detection flag Fpc, the integration term update continuation flag Fiu, and the consumption flow rate stabilization flag Ffr are all values 1, it is determined that the feedback integration term αbi is reliable, and the process proceeds to step S590. That is, when the fuel pressure convergence is detected, the update duration of the feedback integral term αbi is equal to or longer than the predetermined time Tiu, and the fuel consumption flow rate Qfr of the engine 12 is stable, the process proceeds to step S590.

Then, a value obtained by subtracting the low response processing value βlo from the high response processing value βhi is set in the difference Δβ1 (step S590), and the set difference Δβ1 is compared with the threshold value Δβref1 (step S600). Here, the threshold value Δβref1 is used to determine whether or not the difference Δβ1 is relatively large. Consider a case where the fuel in the fuel tank 40 is boiling and the fuel pump 44 sucks in vaporized fuel (mainly fuel vaporized by boiling) and the discharge pressure of the fuel pump 44 drops. At this time, the fuel pressure Pf becomes lower than the target fuel pressure Pf *, and the feedback integral term αbi increases (step S354 in FIGS. 5 to 7). The larger the increase in the feedback integral term αbi per unit time, the larger the difference Δβ1 obtained by subtracting the low response processing value βlo from the high response processing value βhi. Based on this, the process of step S600 is a process of determining whether or not to detect the boiling of the fuel in the fuel tank 40 by using the difference Δβ1.

When the difference Δβ1 is equal to or greater than the threshold value Δβref1 in step S600, it is determined that boiling of the fuel in the fuel tank 40 is detected under the condition of the difference Δβ1, and a value 1 is set in the provisional detection flag Fv2b (step S602). When the difference Δβ1 is less than the threshold value Δβref1, the value 0 is set in the provisional detection flag Fv2b without determining that the boiling of the fuel in the fuel tank 40 is detected under the condition of the difference Δβ1 (step S604). In order to suppress erroneous determination, the temporary detection flag Fv2b may be set to a value 1 when the difference Δβ1 is the threshold value Δβref1 or more and the duration thereof is Tβ1 or more for a predetermined time. As the predetermined time Tβ1, the time required to determine that the difference Δβ1 is equal to or greater than the threshold value Δβref1, for example, about several hundred msec is used.

The processing of steps S600 to S604 will be described with reference to the explanatory diagram of FIG. FIG. 14 is an explanatory diagram showing an example of the state of the target fuel pressure Pf *, the fuel pressure Pf, the feedback integral term αbi, the high response processing value βhi, the low response processing value βlo, the difference Δβ1, and the provisional detection flag Fv2b. When the fuel pump 44 sucks in vaporized fuel (mainly fuel vaporized by boiling) and the discharge pressure of the fuel pump 44 decreases, the feedback integral term αbi increases, and along with this, the high response processing value βhi and the low response processing value βlo Increases (time t11 ~). Then, when the difference Δβ1 obtained by subtracting the low response processing value βlo from the high response processing value βhi reaches the threshold value Δβref1 or more (time t12), the value 1 is set in the provisional detection flag Fv2b. In this way, boiling of fuel in the fuel tank 40 can be detected under the condition of the difference Δβ1.

Further, a value obtained by subtracting the convergence processing value βhi0 from the current high response processing value βhi is set in the difference Δβ2 (step S610), and the set difference Δβ2 is compared with the threshold value Δβref2 (step S620). Here, the threshold value Δβref2 is used to determine whether or not the difference Δβ2 is relatively large. Even when the fuel in the fuel tank 40 is boiling and the fuel pump 44 sucks in vaporized fuel (mainly the fuel vaporized by boiling) and the discharge pressure of the fuel pump 44 decreases, the feedback integral term αbi increases per unit time. When the amount is not so large, the difference Δβ1 may not be equal to or greater than the threshold Δβref1. Even in this case, if the feedback integral term αbi continues to increase, the high response processing value βhi continues to increase, and the difference Δβ2 obtained by subtracting the convergence processing value βhi0 from the high response processing value βhi may become relatively large. be. Based on this, step S620 is a process of determining whether or not to detect boiling of fuel in the fuel tank 40 using the difference Δβ2.

When the difference Δβ2 is equal to or greater than the threshold value Δβref2 in step S620, it is determined that boiling of the fuel in the fuel tank 40 is detected under the condition of the difference Δβ2, and a value 1 is set in the provisional detection flag Fv2c (step S622). When the difference Δβ2 is less than the threshold value Δβref2, the temporary detection flag Fv2c is set to a value 0 without determining that boiling of the fuel in the fuel tank 40 is detected under the condition of the difference Δβ2 (step S624). In order to suppress erroneous determination, the temporary detection flag Fv2c may be set to a value 1 when the difference Δβ2 is the threshold value Δβref2 or more and the duration thereof is Tβ2 or more for a predetermined time. As the predetermined time Tβ2, the time required to determine that the difference Δβ2 is equal to or greater than the threshold value Δβref2, for example, about several hundred msec is used.

The processing of steps S620 to S624 will be described with reference to the explanatory diagram of FIG. FIG. 15 is an explanatory diagram showing an example of the state of the target fuel pressure Pf *, the fuel pressure Pf, the feedback integral term αbi, the high response processing value βhi, the low response processing value βlo, the difference Δβ1, Δβ, and the provisional detection flags Fv2b and Fv2c. .. When the fuel pump 44 sucks in vaporized fuel (mainly fuel vaporized by boiling) and the discharge pressure of the fuel pump 44 decreases, the feedback integral term αbi increases, and along with this, the high response processing value βhi and the low response processing value βlo Increases (time t21 ~). Even if the difference Δβ1 obtained by subtracting the low response processing value βlo from the high response processing value βhi is less than the threshold value Δβref1, the difference Δβ2 obtained by subtracting the convergence processing value βhi0 from the high response processing value βhi is the threshold value Δβref2. When the above is reached (time t22), the value 1 is set in the temporary detection flag Fv2c. In this way, boiling of fuel in the fuel tank 40 can be detected under the condition of the difference Δβ2.

When the temporary detection flags Fv2a, Fv2b, and Fv2c are set in this way, the values of the set temporary detection flags Fv2a, Fv2b, and Fv2c are checked (steps S630 to S634). When at least one of the provisional detection flags Fv2a, Fv2b, and Fv2c has a value of 1, the value 1 is set in the fuel boiling detection flag Fv (step S632), and this routine is terminated. That is, the boiling of the fuel in the fuel tank 40 is detected by at least one of the condition of the purge concentration-related value Cpg (step S560), the condition of the difference Δβ1 (step S600), and the condition of the difference Δβ2 (step S620). When it is determined that the fuel boiling detection flag Fv is set to a value of 1. In this way, boiling of fuel in the fuel tank 40 can be detected (changed from undetected to detected or held by detection).

When all of the provisional detection flags Fv2a, Fv2b, and Fv2c are values 0 in steps S630 to S634, the fuel boiling detection flag Fv is held at the previous value (step S634), and this routine is terminated. That is, if the boiling of the fuel in the fuel tank 40 is detected under any of the conditions of the purge concentration-related value Cpg (step S560), the condition of the difference Δβ1 (step S600), and the condition of the difference Δβ2 (step S620). When the judgment is not made, the fuel boiling detection flag Fv is held at the previous value.

In steps S570 to S574, when at least one of the fuel pressure convergence detection flag Fpc, the integration term update continuation flag Fiu, and the consumption flow rate stabilization flag Ffr has a value of 0, the process proceeds to step S580. That is, when the fuel pressure convergence is not detected or when the update duration of the feedback integral term αbi is less than the predetermined time Tiu (including when the feedback integral term αbi is not updated), the fuel consumption flow rate Qfr of the engine 12 If is not stable, the process proceeds to step S580.

Subsequently, the value of the temporary detection flag Fv2a is examined (step S580). When the provisional detection flag Fv2a has a value of 1, the value 1 is set in the fuel boiling detection flag Fv (step S582), and this routine ends. That is, when it is determined that the boiling of the fuel in the fuel tank 40 is detected according to the condition of the purge concentration-related value Cpg (step S560), the value 1 is set in the fuel boiling detection flag Fv. In this way, boiling of fuel in the fuel tank 40 can be detected (changed from undetected to detected or held by detection).

When the temporary detection flag Fv2a has a value of 0 in step S580, the fuel boiling detection flag Fv is held at the previous value (step S584), and this routine ends. That is, when it is not determined that the boiling of the fuel in the fuel tank 40 is detected under the condition of the purge concentration-related value Cpg (step S560), the fuel boiling detection flag Fv is held at the previous value.

Here, when the fuel pressure convergence is not detected or when the update duration of the feedback integral term αbi is less than the predetermined time Tiu (including when the feedback integral term αbi is not updated), the fuel consumption flow rate of the engine 12 The reason why the provisional detection flags Fv2b and Fv2c are not used for setting the fuel boiling detection flag Fv when Qfr is not stable will be described.

When the fuel pressure convergence is not detected, the fuel pressure Pf may fluctuate relatively greatly, and the feedback integral term αbi may also fluctuate relatively significantly accordingly, so that the reliability of the difference Δβ1 cannot be guaranteed. Further, the difference Δβ2 cannot be calculated because the processing value βhi0 at the time of convergence cannot be set. For this reason, in order to suppress the misjudgment as to whether or not to detect the boiling of the fuel in the fuel tank 40, when the fuel pressure convergence is not detected, the provisional detection flag Fv2b, in the setting of the fuel boiling detection flag Fv, It was decided not to use Fv2c.

When the feedback integral term αbi is not updated, the reliability of the feedback integral term αbi cannot be guaranteed, so the reliability of the differences Δβ1 and Δβ2 cannot be guaranteed either. Further, even if the feedback integral term αbi is updated, when the update duration is short, the feedback integral term αbi may fluctuate relatively greatly, and the reliability of the differences Δβ1 and Δβ2 cannot be guaranteed. For this reason, in order to suppress an erroneous judgment as to whether or not to detect boiling of fuel in the fuel tank 40, when the update duration of the feedback integral term αbi is less than the predetermined time Tiu (feedback integral term αbi is updated). The provisional detection flags Fv2b and Fv2c are not used for setting the fuel boiling detection flag Fv.

When the fuel consumption flow rate Qfr of the engine 12 is not stable, the fuel pressure Pf may fluctuate relatively large, and the feedback proportional term αbp and the feedback integral term αbi may also fluctuate relatively significantly accordingly. Yes, the reliability of the differences Δβ1 and Δβ2 cannot be guaranteed. For this reason, in order to suppress an erroneous determination as to whether or not to detect the boiling of fuel in the fuel tank 40, when the fuel consumption flow rate Qfr of the engine 12 is not stable, the fuel boiling detection flag Fv is set. The provisional detection flags Fv2b and Fv2c are not used.

In the engine device 11 included in the automobile 10 of the above-described embodiment, the feedback integral term αbi in the fuel pressure feedback control is subjected to a highly responsive tanning process to calculate a high response processing value βhi and a low response to the feedback integral term αbi. When the difference Δβ1 obtained by performing the sexual tanning process to calculate the low response processing value βlo and subtracting the low response processing value βlo from the high response processing value βhi is equal to or greater than the threshold value Δβref1, the fuel in the fuel tank 40 Detect boiling. Further, when the difference Δβ2 obtained by subtracting the convergence processing value βhi0, which is the high response processing value βhi immediately after changing the fuel pressure convergence from undetected to detected from the current high response processing value βhi, is the threshold value δβref2 or more. The boiling of the fuel in the fuel tank 40 is detected. Further, when the condition of the purge concentration-related value Cpg is satisfied, boiling of the fuel in the fuel tank 40 is detected. In these ways, boiling of fuel in the fuel tank 40 can be detected.

In the engine device 11 of the embodiment, in the fuel pump control routine of FIGS. 5 to 7, when the fuel boiling detection flag Fv is a value 1 in step S320, the valve opening pressure Pfrv of the relief valve 46 is set to the target fuel pressure Pf in step S380. It was set to *. However, the present invention is not limited to this, and when the fuel boiling detection flag Fv has a value of 1, a higher value may be set as the target fuel pressure Pf * as compared with the case where the value is 0.

In the engine device 11 of the embodiment, in the fuel pump control routine of FIGS. 5 to 7, when the fuel boiling detection flag Fv is a value 1 in step S320, the temporary rotation speed Nptmp of the fuel pump 44 is set to the lower limit rotation speed in step S404. The values guarded at the upper and lower limits by Npmin and the upper limit rotation speed Npmax are set to the target rotation speed Np *. However, when the fuel boiling detection flag Fv is a value 1, the value obtained by guarding the temporary rotation speed Nptmp of the fuel pump 44 with the upper limit rotation speed Npmax may be set to the target rotation speed Np *, or the fuel pump 44 may be set. The temporary rotation speed Nptmp of the fuel pump 44 may be set to the target rotation speed Np * with the lower limit guarded by the lower limit rotation speed Npmin, or the temporary rotation speed Nptmp of the fuel pump 44 may be set to the target rotation speed Np *. good.

In the engine device 11 of the embodiment, in the fuel pump control routine of FIGS. 5 to 7, when the fuel boiling detection flag Fv has a value of 1 in step S320, that is, when the pump control during boiling is executed, boiling is performed in step S408. The integrated execution time Tfup of the hour pump control was measured. That is, when the pump control at the time of boiling is executed, the integrated execution time Tfup is uniformly measured regardless of the factors caused by the execution. However, the integrated execution time Tfup [i] (i: variable for the factor) may be clocked for each factor caused by the execution of the pump control at the time of boiling. As each factor, for example, the provisional undetected flag Fv1a is a value 1 (purge concentration-related value Cpg is less than the threshold value Cpgref2), and the provisional detection flag Fv2b and / or the provisional detection flag Fv2c (difference Δβ1 is). The threshold value Δβref1 or more and / or the difference Δβ2 is the threshold value Δβref2 or more). By doing so, various analyzes can be performed more appropriately by the manufacturer, the dealer, or the like.

In the engine device 11 of the embodiment, as the control of the fuel pump 44, the electronic control unit 70 is assumed to execute the fuel pump control routine of FIGS. 5 to 7. However, instead of this, the electronic control unit 70 may execute the fuel pump control routine of FIGS. 5 to 7 by replacing the portion of FIG. 6 with the portion of FIG. A part of the fuel pump control routine of FIG. 16 differs from a part of the fuel pump control routine of FIG. 6 in that the processing of steps S430 to S434 is added.

In a part of the fuel pump control routine of FIG. 16, when the integrated execution time Tfup of the boiling pump control is timed in step S408, the convergence time processing value βhi0 can be input (step S430), and the convergence time processing. The value βhi0 is input (step S432), the input convergent processing value βhi0 is set in the feedback integration term αbi (step S434), and this routine is terminated. Here, the fact that the convergence processing value βhi0 can be input means that the convergence processing value βhi0 is set in step S516 of the fuel boiling detection flag setting routine of FIGS. 10 to 12 and has not been reset. do.

The processing of steps S430 to S434 will be described with reference to the explanatory diagram of FIG. FIG. 17 is an explanatory diagram showing an example of a target fuel pressure Pf *, a fuel pressure Pf, a feedback integral term αbi, a high response processing value βhi, a fuel pressure convergence detection flag Fpc, and a fuel boiling detection flag Fv. When the condition that the fuel pressure difference ΔPf is equal to or less than the threshold value ΔPref and the duration thereof is Tpf or more for a predetermined time is satisfied (time t31), the fuel pressure convergence detection flag Fpc is switched from the value 0 to the value 1 and the high response processing value at that time is satisfied. Set βhi to the convergence processing value βhi0. After that, the fuel pump 44 sucks in the vaporized fuel (mainly the fuel vaporized by boiling), the discharge pressure of the fuel pump 44 decreases, and the feedback integration term αbi and the high response processing value βhi increase accordingly. When the fuel boiling detection flag Fv switches from the value 0 to the value 1 under the conditions of the purge concentration related value Cpg, the difference Δβ1, and the difference Δβ2 (time t32), the target fuel pressure Pf * is increased to the valve opening pressure Pfrv of the relief valve 46. The high response processing value βhi is set to the convergence processing value βhi0.

It is assumed that the feedback integral term αbi set in step S354 immediately before the fuel boiling detection flag Fv switches from the value 0 to the value 1 includes the influence of boiling the fuel in the fuel tank 40. .. Therefore, if the feedback integral term αbi is set (updated) in step S354 after the fuel boiling detection flag Fv is switched from the value 1 to the value 0 without performing the process of step S434, the feedback integral term αbi is set to the fuel tank 40. There is a possibility that the value will include the effect when the fuel inside is boiling. Based on this, in this modification, when the fuel boiling detection flag Fv is a value 1, the convergence processing value βhi0 is set to the feedback integral term αbi. As a result, when the feedback integral term αbi is set (updated) in step S354 after the fuel boiling detection flag Fv is switched from the value 1 to the value 0, the feedback integral term αbi can be set to a more appropriate value.

In the fuel pump control routine of FIG. 16, when the fuel boiling detection flag Fv is a value 1 in step S320, the convergence processing value βhi0 is set to the feedback integration term αbi in step S434. However, instead of this, when the fuel boiling detection flag Fv is a value 1, the feedback integral immediately after the fuel pressure convergence detection flag Fpc is switched from the value 0 to the value 1 (immediately after the fuel pressure convergence is changed from undetected to detected). The feedback integration term αbi0 at the time of convergence, which is the term αbi, may be set to the feedback integration term αbi.

In the engine device 11 of the embodiment, in the fuel pump control routines of FIGS. 5 to 7, the engine rotation flag Ferr is a value 1 in step S310, the fuel boiling detection flag Fv is a value 0 in step S320, and the fuel boiling detection flag Fv is a value 0 in step S340. When the fuel cut flag Ffc1 has a value of 0, the feedback integration term αbi is set in step S354. However, instead of this, when the engine rotation flag Ferr is a value 1, the fuel boiling detection flag Fv is a value 0, and the fuel cut flag Ffc1 is a value 0, the feedback integration is performed by the feedback integration term setting process in FIG. The term αbi may be set.

In the feedback integration term setting process of FIG. 18, the electronic control unit 70 first sets the absolute value of the target fuel pressure Pf *, which is obtained by subtracting the previous value from the current value, as the target fuel pressure change amount δPf * (step S800). ), The absolute value of the value obtained by subtracting the fuel pressure Pf from the target fuel pressure Pf * is set in the fuel pressure difference ΔPf2 (step S810). Subsequently, the target fuel pressure change amount δPf * is compared with the threshold value δPref (step S820). Here, the threshold value δPref is used to determine whether or not the target fuel pressure Pf * has changed relatively significantly. As this threshold value δPref, a value smaller than the target fuel pressure change amount δPf * when the fuel boiling detection flag Fv switches from the value 1 to the value 0 is used.

When the target fuel pressure change amount δPf * is less than the threshold value δPref in step S820, it is determined that the target fuel pressure change amount δPf * has not changed so much, and the value of the large change flag Fch is examined (step S840). Here, the large change flag Fch is set to a value 1 when the target fuel pressure change amount δPf * becomes equal to or greater than the threshold value δPFref by this routine, and then a value 0 is set when the release condition is satisfied. Is. For this large change flag Fch, for example, a value 0 as an initial value is set at the start of a trip. When the value of the large change flag Fch is 0 in step S840, the feedback integral term αbi is set by the above equation (2) in the same manner as in the process of step S354 of the fuel pump control routine of FIGS. 5 to 7 (step S880). , The feedback integral term setting process is terminated.

When the target fuel pressure change amount δPf * is equal to or greater than the threshold value δPref in step S820, it is determined that the target fuel pressure Pf * has changed relatively significantly, a value 1 is set for the large change flag Fch (step S822), and the target fuel pressure change. For the elapsed time Tch after the quantity δPf * becomes equal to or greater than the threshold value δPref, the value 0 is reset and then the time counting is started (step S824).

Subsequently, the factor that the target fuel pressure change amount δPf * becomes equal to or higher than the threshold value δPref is investigated (step S826). When the reason why the target fuel pressure change amount δPf * becomes equal to or higher than the threshold value δPref is not that the fuel boiling detection flag Fv is switched from the value 1 to the value 0, the upper limit time Tchlim for holding the large change flag Fch at the value 1 is set to Tch1 for a predetermined time. Is set (step S828). On the other hand, when the reason why the target fuel pressure change amount δPf * becomes equal to or higher than the threshold value δPref is that the fuel boiling detection flag Fv is switched from the value 1 to the value 0, the upper limit time Tchlim is set to the predetermined time Tch2 shorter than the predetermined time Tch1. Set (step S830). Here, as the predetermined time Tch1, about several thousand to tens of thousands of msec are used, and as the predetermined time Tch1, about 1/3 to 2/3 of the predetermined time Tch1 is used. Then, the feedback integral term αbi is held at the previous value (step S860), and the feedback integral term setting process is terminated. If the feedback integral term αbi is updated when the target fuel pressure change amount δPf * is relatively large, the absolute value of the feedback integral term αbi becomes larger, and the fuel pressure Pf overshoots or undershoots with respect to the target fuel pressure Pf *. There is a possibility that it will happen. Therefore, when the target fuel pressure change amount δPf * is equal to or greater than the threshold value δPref, the feedback integral term αbi is held at the previous value.

When the target fuel pressure change amount δPf * is less than the threshold value δPref in step S820 and the large change flag Fch is a value 1 in step S840, the elapsed time Tch is compared with the upper limit time Tchlim (step S850). When the elapsed time Tch is less than the upper limit time Tchlim, the elapsed time Tch is compared with the threshold value Tchref (step S852), and the fuel pressure difference ΔPf2 is compared with the threshold value ΔPref2 (step S854). Here, as the predetermined time Tchref, the time during which the fuel pressure Pf can reach the vicinity of the target fuel pressure Pf * is used after the target fuel pressure change amount δPf * becomes equal to or higher than the threshold value δPref. The threshold value ΔPref2 is used to determine whether or not the fuel pressure Pf has reached the vicinity of the target fuel pressure Pf * after the target fuel pressure change amount δPf * becomes equal to or higher than the threshold value δPref.

In steps S852 and S854, when the elapsed time Tch is less than the threshold value Tchref or the fuel pressure difference ΔPf2 is larger than the threshold value ΔPref2, the fuel pressure Pf becomes near the target fuel pressure Pf * after the target fuel pressure change amount δPf * becomes equal to or more than the threshold value δPref. It is determined that the time that can be reached has not elapsed and / or the fuel pressure Pf has not reached the vicinity of the target fuel pressure Pf *, the feedback integral term αbi is held at the previous value (step S860), and the feedback integral term is set. End the process.

In steps S852 and S854, when the elapsed time Tch is equal to or greater than the threshold value Tchref and the fuel pressure difference ΔPf2 is equal to or less than the threshold value ΔPref2, the fuel pressure Pf becomes near the target fuel pressure Pf * after the target fuel pressure change amount δPf * becomes equal to or greater than the threshold value δPref. It is determined that the reachable time has elapsed and the fuel pressure Pf has reached the vicinity of the target fuel pressure Pf *, a value 0 is set for the large change flag Fch (step S870), and the feedback integration term is processed by the above-mentioned step S880. Set αbi and end the feedback integration term setting process.

When the elapsed time Tch is equal to or greater than the upper limit time Tchlim in step S850, the value 0 is set in the large change flag Fch (step S870), the feedback integration term αbi is set by the process of step S880 described above, and the feedback integration term is set. End the process. In this modification, when the reason why the target fuel pressure change amount δPf * becomes equal to or higher than the threshold value δPref is that the fuel boiling detection flag Fv is switched from the value 1 to the value 0, the upper limit time Tchlim is compared with other times. By shortening the fuel pressure Pf, it is possible to further suppress the time required for the fuel pressure Pf to reach the vicinity of the target fuel pressure Pf *.

In the engine device 11 of the embodiment, in the fuel pump control routines of FIGS. 5 to 7, when the engine rotation flag Ferr has a value of 0 in step S310, the fuel pump 44 is set to the rotation stop state. However, regardless of the value of the engine rotation flag Ferr, the normal pump control or the boiling pump control may be executed based on the fuel boiling detection flag Fv.

In the engine device 11 of the embodiment, in the fuel boiling detection flag setting routine of FIGS. 10 to 12, a constant value is used as the threshold value Cpgref1 used for comparison with the purge concentration-related value Cpg in step S522. However, the threshold Cpgref1 may be set based on the atmospheric pressure Pout. In this case, the threshold value Cpgref1 can be set by applying, for example, the atmospheric pressure Pout to the map for setting the first purge concentration threshold value. The map for setting the first purge concentration threshold value is predetermined as the relationship between the atmospheric pressure Pout and the threshold value Cpgref1 and is stored in the ROM or the flash memory of the electronic control unit 70. FIG. 19 is an explanatory diagram showing an example of a map for setting a first purge concentration threshold value. As shown in the figure, the threshold value Cpgref1 is set so as to become larger (the absolute value becomes smaller) as the atmospheric pressure Pout becomes lower in the negative range. This is because the lower the atmospheric pressure Pout, the easier it is for the absolute pressure in the fuel tank 40 to be lower than the saturated vapor pressure of the fuel, and the easier it is for the fuel in the fuel tank 40 to boil. This is to make it difficult to detect the boiling of the fuel in the tank 40.

In the engine device 11 of the embodiment, in the fuel boiling detection flag setting routine of FIGS. 10 to 12, a constant value is used as the threshold value Tareff used for comparison with the intake air temperature Ta in step S540. However, the threshold value Taref may be set based on the atmospheric pressure Pout. In this case, the threshold value Taref can be set by applying, for example, the atmospheric pressure Pout to the intake air temperature threshold value setting map. The intake temperature threshold setting map is predetermined as the relationship between the atmospheric pressure Pout and the threshold Taref, and is stored in the ROM or flash memory of the electronic control unit 70. FIG. 20 is an explanatory diagram showing an example of an intake air temperature threshold setting map. As shown in the figure, the threshold value Taref is set so that the lower the atmospheric pressure Pout, the lower the threshold value. This is based on the same reason as the tendency of the map for setting the first purge concentration threshold.

In the engine device 11 of the embodiment, in the fuel boiling detection flag setting routine of FIGS. 10 to 12, the provisional undetected flag Fv1c is set by using the intake air temperature Ta in step S540. However, instead of the intake air temperature Ta, the provisional undetected flag Fv1c may be set using the fuel temperature Tf, which is the temperature of the fuel in the fuel tank 40. Here, the fuel temperature Tf may be estimated based on the intake air temperature Ta, or may be detected by the temperature sensor attached to the fuel tank 40.

In the engine device 11 of the embodiment, in the fuel boiling detection flag setting routine of FIGS. 10 to 12, a constant value is used as the threshold value Cpgref2 used for comparison with the purge concentration-related value Cpg in step S560. However, the threshold Cpgref2 may be set based on the atmospheric pressure Pout. In this case, the threshold value Cpgref2 can be set by applying, for example, the atmospheric pressure Pout to the map for setting the second purge concentration threshold value. The map for setting the second purge concentration threshold value is predetermined as the relationship between the atmospheric pressure Pout and the threshold value Cpgref2, and is stored in the ROM or the flash memory of the electronic control unit 70. FIG. 21 is an explanatory diagram showing an example of a map for setting a second purge concentration threshold. As shown in the figure, the threshold value Cpgref2 is set so as to become larger (the absolute value becomes smaller) as the atmospheric pressure Pout becomes lower in the negative range. This is because the lower the atmospheric pressure Pout, the easier it is for the absolute pressure in the fuel tank 40 to be lower than the saturated vapor pressure of the fuel, and the easier it is for the fuel in the fuel tank 40 to boil. This is to facilitate detection of boiling of fuel in the tank 40.

In the engine device 11 of the embodiment, in the fuel boiling detection flag setting routine of FIGS. 10 to 12, a constant value is used as the threshold value Δβref1 used for comparison with the difference Δβ1 in step S600. However, the threshold value Δβref1 may be set based on the atmospheric pressure Pout. In this case, the threshold value Δβref1 can be set by applying, for example, the atmospheric pressure Pout to the first difference threshold value setting map. The first difference threshold setting map is predetermined as the relationship between the atmospheric pressure Pout and the threshold value Δβref 1, and is stored in the ROM or flash memory of the electronic control unit 70. FIG. 22 is an explanatory diagram showing an example of the first difference threshold setting map. As shown in the figure, the threshold value Δβref1 is set so as to be smaller as the atmospheric pressure Pout is lower in the positive range. This is based on the same reason as the tendency of the map for setting the second purge concentration threshold.

In the engine device 11 of the embodiment, in the fuel boiling detection flag setting routine of FIGS. 10 to 12, a constant value is used as the threshold value Δβref2 used for comparison with the difference Δβ2 in step S620. However, the threshold value Δβref2 may be set based on the atmospheric pressure Pout. In this case, the threshold value Δβref2 can be set by applying, for example, the atmospheric pressure Pout to the second difference threshold value setting map. The second difference threshold setting map is predetermined as the relationship between the atmospheric pressure Pout and the threshold value Δβref2, and is stored in the ROM or flash memory of the electronic control unit 70. FIG. 23 is an explanatory diagram showing an example of a second difference threshold setting map. As shown in the figure, the threshold value Δβref2 is set to be smaller as the atmospheric pressure Pout is lower in the positive range. This is based on the same reason as the tendency of the map for setting the second purge concentration threshold.

In the engine device 11 of the embodiment, in the fuel boiling detection flag setting routine of FIGS. 10 to 12, a value obtained by subtracting the low response processing value βlo from the high response processing value βhi in step S590 is set as the difference Δβ1. However, the difference Δβ1 may be set to a value obtained by subtracting the low response processing value βlo from the feedback integral term αbi.

In the engine device 11 of the embodiment, in the fuel boiling detection flag setting routine of FIGS. 10 to 12, a value obtained by subtracting the convergence processing value βhi0 from the current high response processing value βhi in step S610 is set as the difference Δβ2. did. However, the feedback integral term αbi immediately after the fuel pressure convergence detection flag Fpc is switched from the value 0 to the value 1 is stored as the feedback integral term αbi0 at the time of convergence, and the feedback integral term αbi0 at the time of convergence is subtracted from the current feedback integral term αbi. The value may be set to the difference Δβ2.

In the engine device 11 of the embodiment, in the fuel boiling detection flag setting routine of FIGS. 10 to 12, the purge concentration learning is performed in the determination process (steps S550 to S554) of whether or not to set the value 0 for the fuel boiling detection flag Fv. Temporary undetected flag Fv1a based on the presence or absence of the condition of the number of times Npg, purge concentration related value Cpg and tank internal pressure Pt, provisional undetected flag Fv1b based on the presence or absence of the condition of cooling water temperature Tw, and the condition of intake air temperature Ta It was decided to use the provisional undetected flag Fv1c based on the presence or absence of establishment. However, in this determination process, only a part of the provisional undetected flags Fv1a, Fv1b, and Fv1c may be used.

In the engine device 11 of the embodiment, in the fuel boiling detection flag setting routine of FIGS. 10 to 12, in the determination process (steps S630 to S634) of whether or not to set the value 1 for the fuel boiling detection flag Fv, the purge concentration is related. The provisional detection flag Fv2a based on the presence or absence of the condition of the value Cpg, the provisional detection flag Fv2b based on the presence or absence of the condition of the difference Δβ1, and the provisional detection flag Fv2c based on the presence or absence of the condition of the difference Δβ2 are used. However, in this determination process, at least the temporary detection flag Fv2b may be used, and at least one of the temporary detection flags Fv2a and Fv2c may not be used.

In the engine device 11 of the embodiment, in the fuel boiling detection flag setting routine of FIGS. 10 to 12, it is determined whether or not the provisional detection flags Fv2b and Fv2c are used for setting the fuel boiling detection flag Fv (steps S570 to S574). Therefore, the fuel pressure convergence detection flag Fpc, the integration term update continuation flag Fiu, and the consumption flow rate stabilization flag Ffr are used. However, in this determination process, at least the fuel pressure convergence detection flag Fpc may be used, and at least one of the integral term update continuation flag Fiu and the consumption flow rate stabilization flag Ffr may not be used.

In the engine device 11 of the embodiment, in the fuel pressure convergence detection flag setting routine of FIG. 13, the absolute value of the value obtained by subtracting the pulsation center fuel pressure Pfcn from the target fuel pressure Pf * is set in the fuel pressure difference ΔPf in step S730. However, instead of this, the absolute value of the value obtained by subtracting the fuel pressure Pf from the target fuel pressure Pf * may be set in the fuel pressure difference ΔPf.

In the engine device 11 of the embodiment, in the fuel pressure convergence detection flag setting routine of FIG. 13, in the determination process (steps S710 to S714) of whether or not to set the value 0 in the fuel pressure convergence detection flag Fpc, the fuel pump rotation flag Fpr, The target fuel pressure Pf * and the fuel cut continuation flag Ffc2 were used. However, in this determination process, only a part of the fuel pump rotation flag Fpr, the target fuel pressure Pf *, and the fuel cut continuation flag Ffc2 may be used.

In the engine device 11 included in the automobile 10 of the embodiment, the engine 12 is provided with a fuel injection valve 26 (in-cylinder injection valve) for injecting fuel into the cylinder. However, instead of or in addition to the fuel injection valve 26, a port injection valve for injecting fuel to the intake port may be provided.

In the embodiment, the engine device 11 included in the automobile 10 traveling by using the power from the engine 12 is used. However, the engine 12 may be in the form of an engine device 11 included in a vehicle capable of intermittent operation, and may be in the form of an engine device 11 included in a hybrid vehicle having a motor in addition to the engine.

The correspondence between the main elements of the embodiment and the main elements of the invention described in the column of means for solving the problem will be described. In the embodiment, the engine 12 corresponds to the "engine", the fuel supply device 42 corresponds to the "fuel supply device", and the electronic control unit 70 corresponds to the "control device".

As for the correspondence between the main elements of the examples and the main elements of the invention described in the column of means for solving the problem, the invention described in the column of means for solving the problems of the examples is carried out. Since it is an example for specifically explaining the mode for solving the problem, the elements of the invention described in the column of means for solving the problem are not limited. That is, the interpretation of the invention described in the column of means for solving the problem should be performed based on the description in the column, and the examples are the inventions described in the column of means for solving the problem. It is just a concrete example.

Although the embodiments for carrying out the present invention have been described above with reference to the embodiments, the present invention is not limited to these embodiments and may be in various embodiments within the scope of the gist of the present invention. Of course it can be done.

The present invention can be used in the manufacturing industry of engine devices and the like.

10 Automobile, 11 Engine Equipment, 12 Engine, 14 Crank Shaft, 14a Crank Position Sensor, 15 Water Temperature Sensor, 16 Cam Position Sensor, 22 Air Cleaner, 23 Intake Pipe, 23a Air Flow Meter, 23b Temperature Sensor, 24 Throttle Valve, 24a Throttle Position Sensor, 26 fuel injection valve, 28 intake valve, 29 combustion chamber, 30 ignition plug, 32 piston, 33 exhaust valve, 34 exhaust pipe, 35 purification device, 37 front air fuel ratio sensor, 38 rear air fuel ratio sensor, 40 fuel tank, 40a pressure sensor, 42 fuel supply device, 43 fuel flow path, 43p fuel pressure sensor, 44 fuel pump, 44a discharge hole, 44b rotation speed sensor, 45 relief passage, 46 relief valve, 50 vaporization fuel processing device, 51 introduction passage, 52 Block valve, 52a block valve position sensor, 53 canister, 54 open air passage, 55 purge passage, 56 purge valve, 56a purge valve position sensor, 60 transmission, 62 differential gear, 64a, 64b drive wheel, 70 electronic control unit, 80 ignition Switch, 81 shift lever, 82 shift position sensor, 83 accelerator pedal, 84 accelerator pedal position sensor, 85 brake pedal, 86 brake pedal position sensor, 88 vehicle speed sensor, 89 atmospheric pressure sensor.

Claims (1)

With the engine
A fuel supply device having a fuel pump for supplying fuel in a fuel tank to a fuel flow path connected to a fuel injection valve of the engine.
Control to control the fuel pump by setting the target discharge flow rate of the fuel pump using feedback control by the proportional term and the integral term based on the difference between the fuel pressure which is the pressure of the fuel in the fuel flow path and the target fuel pressure. With the equipment
It is an engine device equipped with
The control device has a second responsiveness lower than the first responsiveness to the integral term from the first processing value obtained by subjecting the integral term or the integral term to the first responsive tanning process. Further, the difference is calculated by subtracting the second processing value obtained by performing the processing, and when the difference is equal to or greater than the difference threshold, boiling of the fuel in the fuel tank is detected.
Engine equipment.

Images