WO2024252505A1 - Procédé de commande de moteur à combustion interne et dispositif de commande de moteur à combustion interne - Google Patents

Procédé de commande de moteur à combustion interne et dispositif de commande de moteur à combustion interne Download PDF

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Publication number
WO2024252505A1
WO2024252505A1 PCT/JP2023/020908 JP2023020908W WO2024252505A1 WO 2024252505 A1 WO2024252505 A1 WO 2024252505A1 JP 2023020908 W JP2023020908 W JP 2023020908W WO 2024252505 A1 WO2024252505 A1 WO 2024252505A1
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Prior art keywords
correction coefficient
air
fuel ratio
internal combustion
combustion engine
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English (en)
Japanese (ja)
Inventor
稔 沼田
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Nissan Motor Co Ltd
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Nissan Motor Co Ltd
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Priority to PCT/JP2023/020908 priority Critical patent/WO2024252505A1/fr
Publication of WO2024252505A1 publication Critical patent/WO2024252505A1/fr
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    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F02—COMBUSTION ENGINES; HOT-GAS OR COMBUSTION-PRODUCT ENGINE PLANTS
    • F02D—CONTROLLING COMBUSTION ENGINES
    • F02D41/00—Electrical control of supply of combustible mixture or its constituents
    • F02D41/02—Circuit arrangements for generating control signals
    • F02D41/14—Introducing closed-loop corrections
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F02—COMBUSTION ENGINES; HOT-GAS OR COMBUSTION-PRODUCT ENGINE PLANTS
    • F02M—SUPPLYING COMBUSTION ENGINES IN GENERAL WITH COMBUSTIBLE MIXTURES OR CONSTITUENTS THEREOF
    • F02M25/00—Engine-pertinent apparatus for adding non-fuel substances or small quantities of secondary fuel to combustion-air, main fuel or fuel-air mixture
    • F02M25/08—Engine-pertinent apparatus for adding non-fuel substances or small quantities of secondary fuel to combustion-air, main fuel or fuel-air mixture adding fuel vapours drawn from engine fuel reservoir

Definitions

  • the present invention relates to a method for controlling an internal combustion engine and a control device for an internal combustion engine.
  • Patent Document 1 discloses an evaporated fuel treatment device that temporarily stops purging when the turbocharger decreases in order to prevent the air-fuel ratio from becoming excessively rich due to evaporated fuel purging when the turbocharger decreases.
  • Patent Document 1 if the amount of purge gas containing evaporated fuel suddenly decreases, the fuel injection amount correction that has been shifted by the purge gas may not be able to keep up, and the air-fuel ratio may deteriorate (become lean).
  • the internal combustion engine of the present invention uses an air-fuel ratio feedback correction coefficient to feedback control the air-fuel ratio to the theoretical air-fuel ratio, and if the air-fuel ratio feedback correction coefficient deviates from a predetermined reference value due to purge gas containing evaporated fuel from the fuel tank, a step-like decrease in the purge rate causes a correction coefficient initialization process to return the air-fuel ratio feedback correction coefficient to the reference value.
  • an internal combustion engine can bring the air-fuel ratio feedback correction coefficient closer to a value that corresponds to the actual air-fuel ratio, thereby suppressing fluctuations (deterioration) of the air-fuel ratio.
  • 1 is an explanatory diagram that illustrates a schematic overview of a system configuration of an internal combustion engine to which the present invention is applied; 4 is a timing chart showing an example of the behavior of various parameters during purge cut in the internal combustion engine of the first embodiment. 4 is a flowchart showing a flow of control of the internal combustion engine in the first embodiment. 10 is a timing chart showing an example of the behavior of various parameters during purge cut in the internal combustion engine of the second embodiment. 10 is a flowchart showing a flow of control of an internal combustion engine in a second embodiment.
  • FIG. 1 is an explanatory diagram showing a schematic overview of the system configuration of an internal combustion engine 1 to which the present invention is applied.
  • the internal combustion engine 1 is, for example, a multi-cylinder spark-ignition gasoline engine, and is installed as a driving source in a vehicle such as an automobile.
  • the intake passage 2 of the internal combustion engine 1 is provided with an air cleaner 3 that collects foreign matter in the intake air, an air flow meter 4 that detects the amount of intake air, an electric throttle valve 5, and an intake collector 6.
  • the air flow meter 4 is located downstream of the air cleaner 3 in the intake flow direction.
  • the throttle valve 5 controls the amount of intake air into the internal combustion engine 1 depending on the load, and is located downstream of the air flow meter 4 in the intake flow direction.
  • the intake collector 6 is located downstream of the throttle valve 5 in the intake flow direction and is connected to the intake ports 8 of each cylinder of the internal combustion engine 1 via the intake manifold 7.
  • the internal combustion engine 1 also has a turbocharger 9.
  • the turbocharger 9 has a compressor 10 provided in the intake passage 2 and a turbine 11 provided in the exhaust passage 15.
  • the compressor 10 and the turbine 11 are arranged coaxially and rotate together.
  • the compressor 10 is arranged upstream of the throttle valve 5 in the intake flow direction and downstream of the air flow meter 4.
  • An intercooler 12 is provided in the intake passage 2 upstream of the throttle valve 5.
  • the intercooler 12 is disposed downstream of the compressor 10 in the intake air flow direction.
  • the intercooler 12 is provided to cool the intake air compressed (pressurized) by the compressor 10 to improve the filling efficiency.
  • An intake bypass passage 13 is connected to the intake passage 2.
  • the intake bypass passage 13 is formed to bypass the compressor 10 and connect the upstream side and downstream side of the compressor 10.
  • An electric recirculation valve 14 is provided in the intake bypass passage 13.
  • the recirculation valve 14 is normally closed, but is opened when the pressure downstream of the compressor 10 becomes high.
  • the recirculation valve 14 is open, the high-pressure intake air downstream of the compressor 10 can be returned to the upstream side of the compressor 10 via the intake bypass passage 13.
  • the recirculation valve 14 can also be a so-called check valve that opens only when the pressure downstream of the compressor 10 reaches or exceeds a predetermined pressure.
  • An exhaust bypass passage 16 that bypasses the turbine 11 and connects the upstream and downstream sides of the turbine 11 is connected to the exhaust passage 15.
  • An electric wastegate valve 17 that controls the exhaust flow rate in the exhaust bypass passage 16 is arranged in the exhaust bypass passage 16.
  • a catalyst 18 for purifying exhaust gas is disposed downstream of the turbine 11.
  • An A/F sensor 19 is disposed upstream (at the inlet) of this catalyst 18.
  • the A/F sensor 19 is a so-called wide-range air-fuel ratio sensor that has an almost linear output characteristic according to the air-fuel ratio.
  • the intake passage 2 is also connected to an evaporated fuel processing system 21 that processes evaporated fuel in the fuel tank 20.
  • the evaporated fuel treatment system 21 has a purge passage 22, a canister 23 capable of adsorbing and desorbing evaporated fuel, and an electric purge control valve 24 located between the canister 23 and the intake passage 2, and is capable of introducing purge gas containing evaporated fuel from the fuel tank 20 into the intake passage 2.
  • the purge passage 22 introduces fuel vapor into the intake passage 2 and is connected to the intake passage 2 at a position downstream of the throttle valve 5 and upstream of the intake collector 6.
  • the purge passage 22 is provided with a purge control valve 24 and a canister 23 capable of adsorbing and desorbing evaporated fuel.
  • the canister 23 adsorbs evaporated fuel generated in the fuel tank 20.
  • the purge control valve 24 is disposed between the canister 23 and the intake passage 2.
  • the control unit 25 which serves as the control section, is a well-known digital computer equipped with a CPU, ROM, RAM, and an input/output interface. Detection signals from various sensors, such as the air flow meter 4, the A/F sensor 19, the crank angle sensor 26, a pressure sensor 27 that detects the intake pressure (intake manifold pressure) in the intake manifold 7, and an atmospheric pressure sensor 28, are input to the control unit 25.
  • the crank angle sensor 26 detects the crank angle of the crankshaft of the internal combustion engine 1 and is capable of detecting the engine speed of the internal combustion engine 1.
  • the pressure sensor 27 is capable of detecting the intake pressure downstream of the throttle valve 5, and is attached, for example, to the intake collector 6 or the intake manifold 7.
  • the control unit 25 controls the opening and closing of the throttle valve 5, recirculation valve 14, wastegate valve 17, and purge control valve 24 based on detection signals from various sensors.
  • the control unit 25 is also capable of controlling the internal combustion engine 1 so that the air-fuel ratio becomes the theoretical air-fuel ratio by known air-fuel ratio feedback control based on the detection signal of the A/F sensor 19.
  • the control unit 25 calculates an air-fuel ratio feedback correction coefficient ⁇ (ALPHA) based on the detection signal of the A/F sensor 19, and multiplies the basic fuel injection amount by this air-fuel ratio feedback correction coefficient ⁇ , thereby controlling the internal combustion engine 1 so that the air-fuel ratio becomes the theoretical air-fuel ratio.
  • the basic fuel injection amount is calculated using the intake air amount and the engine speed of the internal combustion engine 1. If purging is in progress when purge gas is introduced into the intake passage 2, the basic fuel injection amount is corrected based on the estimated purge gas concentration value.
  • the introduction of purge gas via the purge control valve 24 is basically performed when the conditions for the air-fuel ratio feedback control of the internal combustion engine 1 using the A/F sensor 19 are met.
  • the control unit 25 estimates the concentration of the purge gas.
  • the concentration of the purge gas is estimated, for example, from the amount of variation in the air-fuel ratio feedback correction coefficient ⁇ relative to the amount of purge gas introduced.
  • the estimated concentration of the purge gas is an estimate of the air/fuel ratio in the purge gas.
  • the air-fuel ratio feedback correction coefficient ⁇ will not be able to keep up with the change in the amount of purge gas introduced, and the air-fuel ratio may fluctuate significantly toward the lean side.
  • the internal combustion engine 1 performs a correction coefficient initialization process that quickly returns the air-fuel ratio feedback correction coefficient ⁇ toward the reference value.
  • the purge rate is the ratio of the amount of purge gas to the amount of intake air.
  • a purge cut means stopping the flow of purge gas into the intake passage 2.
  • FIG. 2 is a timing chart showing an example of the behavior of various parameters during purge cut in the internal combustion engine 1 of the first embodiment.
  • Time t1 in Figure 2 is the timing when the accelerator pedal is depressed, the idle state of the internal combustion engine 1 ends, and purging begins.
  • the estimated purge gas concentration value shown by the solid line in Figure 2 is an erroneous estimate to the lean side of the actual purge gas concentration shown by the characteristic line Lc (dashed line) in Figure 2. Therefore, the air-fuel ratio and air-fuel ratio feedback correction coefficient ⁇ of the internal combustion engine 1 shift to the rich side when purging begins.
  • the air-fuel ratio of the internal combustion engine 1 will shift to the rich side when purging begins and the purge rate increases because the correction by the air-fuel ratio feedback correction coefficient ⁇ cannot keep up (is not in time).
  • the air-fuel ratio feedback correction coefficient ⁇ is a value that is a predetermined amount greater than the above-mentioned reference value when the air-fuel ratio is set to the theoretical air-fuel ratio without purge gas being introduced. This is due to product variations in the internal combustion engine 1. Therefore, the estimated purge gas concentration value is erroneously estimated to be lean, as described above.
  • Time t2 in FIG. 2 is the timing when the air-fuel ratio feedback correction coefficient ⁇ reaches a predetermined lower threshold.
  • the air-fuel ratio feedback correction coefficient ⁇ is set so as not to become smaller than the lower threshold, which is a predetermined amount smaller than the reference value.
  • the air-fuel ratio feedback correction coefficient ⁇ becomes the lower threshold value from time t2 in FIG. 2, and is limited so as not to become a smaller value.
  • the purge rate does not change from the value corresponding to the lower threshold value from time t2 in FIG. 2.
  • the judgment threshold value is an index for determining whether or not the air-fuel ratio feedback correction coefficient ⁇ has changed due to purging.
  • the purge rate becomes equal to or greater than the judgment threshold value, it is determined that the air-fuel ratio feedback correction coefficient ⁇ has changed due to purging.
  • the purge rate is equal to or greater than the judgment threshold value, it is determined that the air-fuel ratio feedback correction coefficient ⁇ has become a value that has deviated from the reference value due to the purge gas.
  • Time t3 in FIG. 2 is the timing when the intake pressure (intake manifold pressure) in the intake manifold 7 becomes atmospheric pressure after the accelerator is fully opened.
  • the purge rate becomes "0" at time t3 and falls below the first purge threshold, which is smaller than the above-mentioned judgment threshold.
  • the above-mentioned first purge threshold is an index for determining whether or not purge cut has been performed. In the first embodiment, when the purge rate falls below the above-mentioned first purge threshold, it is determined that purge cut has been performed.
  • the intake pressure in the intake manifold 7 is higher than a preset pressure threshold due to the full accelerator opening prior to time t3.
  • the above-mentioned pressure threshold is set to a value smaller than atmospheric pressure. In this embodiment, it is determined that purge cut has been performed due to supercharging when the intake pressure in the intake manifold 7 becomes higher than the above-mentioned pressure threshold.
  • Time t4 in FIG. 2 is the timing when a predetermined time has elapsed since time t3, and is the timing when the correction coefficient initialization process is performed.
  • the predetermined time is set, for example, so that no purge gas remains in the intake system of the internal combustion engine 1.
  • the dashed characteristic line S1 in FIG. 2 shows the change in the air-fuel ratio feedback correction coefficient ⁇ when the air-fuel ratio feedback correction coefficient ⁇ is not suddenly returned to the reference value at the timing of time t4 (i.e., when feedback control is continued as is).
  • the dashed characteristic line S2 in FIG. 2 shows the change in the air-fuel ratio of the internal combustion engine 1 when the air-fuel ratio feedback correction coefficient ⁇ changes as in the characteristic line S1.
  • the air-fuel ratio of the internal combustion engine 1 is prevented from fluctuating toward the lean side by suddenly returning the air-fuel ratio feedback correction coefficient ⁇ to the reference value at time t4.
  • FIG. 3 is a flowchart showing the flow of control of the internal combustion engine 1 in the first embodiment described above.
  • step S1 it is determined whether or not the purge has been cut off from a state in which the air-fuel ratio feedback correction coefficient ⁇ has deviated from the reference value due to the purge gas.
  • the purge rate and the air-fuel ratio feedback correction coefficient ⁇ are used to determine whether or not the air-fuel ratio feedback correction coefficient ⁇ has deviated from the reference value due to the flow of purge gas into the intake passage 2. If the purge rate is equal to or greater than the determination threshold and the air-fuel ratio feedback correction coefficient ⁇ is equal to or less than the correction coefficient threshold, it is determined that the air-fuel ratio feedback correction coefficient ⁇ has deviated from the reference value due to the purge gas.
  • step S2 it is determined whether the purge rate is less than the first purge threshold. If the purge rate is less than the first purge threshold, the process proceeds to step S3, where the delay timer starts counting. The delay timer measures the predetermined time.
  • step S4 it is determined whether the above-mentioned predetermined time has elapsed since the delay timer started counting. If the above-mentioned predetermined time has elapsed, the process proceeds to step S5.
  • step S5 a correction coefficient initialization process is performed to return the air-fuel ratio feedback correction coefficient ⁇ to a reference value.
  • the correction coefficient initialization process is performed at a timing delayed by the above-mentioned predetermined time from the timing at which the flow of purge gas into the intake passage 2 stops due to supercharging.
  • the internal combustion engine 1 can bring the air-fuel ratio feedback correction coefficient ⁇ closer to a value that corresponds to the actual air-fuel ratio, and can suppress fluctuations (deterioration) in the air-fuel ratio.
  • the internal combustion engine 1 can suppress a large fluctuation in the air-fuel ratio to the lean side when a step-like decrease in the purge rate occurs due to the supply of purge gas being stopped.
  • the internal combustion engine 1 performs the correction coefficient initialization process at a timing delayed by the above-mentioned predetermined time from the timing when the flow of purge gas into the intake passage 2 stops, so that the air-fuel ratio can be prevented from becoming rich.
  • the supply of purge gas stops when the purge control valve 24 closes. Therefore, even if the purge control valve 24 is closed, there is purge gas in the intake passage 2 that has not reached (has not been inhaled into) the combustion chamber of the internal combustion engine 1.
  • the purge gas present in the intake passage 2 of the internal combustion engine 1 immediately after the purge control valve 24 is closed is gradually sent to the combustion chamber of the internal combustion engine 1, and therefore decreases over time. Therefore, the internal combustion engine 1 can prevent the air-fuel ratio from becoming rich by returning the air-fuel ratio feedback correction coefficient ⁇ to a reference value, taking into account the purge gas remaining in the intake passage 2 immediately after the purge control valve 24 is closed.
  • the internal combustion engine 1 determines that the air-fuel ratio feedback correction coefficient has deviated from the reference value due to the purge gas. Therefore, the internal combustion engine 1 can avoid performing the correction coefficient initialization process if the air-fuel ratio feedback correction coefficient ⁇ deviates from the reference value due to factors other than the purge gas.
  • the internal combustion engine 1 performs the correction coefficient initialization process when the air-fuel ratio feedback correction coefficient ⁇ is equal to or less than a predetermined correction coefficient threshold value that is smaller than the reference value. Therefore, the internal combustion engine 1 can prevent the air-fuel ratio from being adversely affected by unnecessary execution of the correction coefficient initialization process.
  • the above correction coefficient threshold is an index of the air-fuel ratio feedback correction coefficient ⁇ that will cause the air-fuel ratio to exceed a preset lean limit value on the lean side if the above correction coefficient initialization process is not performed when the purge rate is decreased in a stepwise manner.
  • the air-fuel ratio feedback correction coefficient ⁇ is equal to or less than the correction coefficient threshold, the air-fuel ratio will exceed the lean limit unless the correction coefficient initialization process is performed when the purge rate decreases in a stepwise manner.
  • the air-fuel ratio feedback correction coefficient ⁇ is equal to or less than the reference value and greater than the correction coefficient threshold, the deviation of the air-fuel ratio feedback correction coefficient from the reference value is small, so that the air-fuel ratio will not exceed the lean limit even if the correction coefficient initialization process is not performed when the purge rate decreases in a stepwise manner.
  • the internal combustion engine 1 performs the correction coefficient initialization process when the air-fuel ratio of the internal combustion engine 1 will exceed the lean limit as a result of a stepwise decrease in the purge rate.
  • the internal combustion engine 1 performs the above correction coefficient initialization process when the intake pressure in the intake manifold 7 is equal to or higher than the above pressure threshold. Therefore, the internal combustion engine 1 can avoid performing the above correction coefficient initialization process due to factors other than supercharging and a decrease in the intake pressure (negative pressure).
  • the internal combustion engine 1 determines that the purge has been cut when the purge rate falls below the first purge threshold. Therefore, the internal combustion engine 1 can avoid performing the correction coefficient initialization process until the amount of purge gas has decreased to a level that does not affect the air-fuel ratio.
  • the second embodiment of the present invention applies the above-mentioned correction coefficient initialization process to an internal combustion engine that does not have a turbocharger 9.
  • the internal combustion engine of the second embodiment has a configuration substantially identical to that of the internal combustion engine 1 of the first embodiment, and when a stepwise decrease in the purge rate occurs due to an increase in intake pressure, the correction coefficient initialization process is performed at a timing delayed by the above-mentioned predetermined time from the timing when the inflow of purge gas into the intake passage 2 falls below the second purge threshold.
  • the second purge threshold is a predetermined value that is set in advance, and is an index for determining whether or not a purge cut has been performed.
  • the purge rate decreases at a rate of change equal to or greater than a predetermined threshold rate of change
  • the purge rate falls below the second purge threshold, and the amount of purge gas supplied becomes a small amount less than a predetermined amount.
  • the rate of change is the amount of fluctuation in the purge rate per unit time.
  • the air-fuel ratio feedback correction coefficient ⁇ is a value that follows the change in the purge ratio when the change in the purge ratio is not sudden (gradual). Therefore, if the correction coefficient initialization process is performed when the purge ratio changes gradually and falls below the second purge threshold, there is a risk that the air-fuel ratio will fluctuate significantly with respect to the target air-fuel ratio (theoretical air-fuel ratio). Therefore, the internal combustion engine of the second embodiment performs the correction coefficient initialization process only when a step-like decrease in the purge ratio occurs.
  • FIG. 4 is a timing chart showing an example of the behavior of various parameters during purge cut in the internal combustion engine of the second embodiment.
  • Time t1 in Figure 4 is the timing when the accelerator pedal is depressed, the idle state of the internal combustion engine ends, and purging begins.
  • the estimated purge gas concentration shown by the solid line in Figure 4 is an erroneous estimate on the lean side compared to the actual purge gas concentration shown by the dashed line Lc in Figure 4. Therefore, the air-fuel ratio and air-fuel ratio feedback correction coefficient ⁇ of the internal combustion engine shift to the rich side when purging begins.
  • the air-fuel ratio feedback correction coefficient ⁇ is a value that is a predetermined amount larger than the above-mentioned reference value when the air-fuel ratio is set to the theoretical air-fuel ratio without purge gas being introduced. This is due to product variations in internal combustion engines. Therefore, the estimated purge gas concentration value is erroneously estimated to be on the lean side, as described above.
  • Time t2 in FIG. 4 is the timing when the air-fuel ratio feedback correction coefficient ⁇ reaches a predetermined lower threshold.
  • the air-fuel ratio feedback correction coefficient ⁇ is set so as not to become smaller than the lower threshold, which is a predetermined amount smaller than the reference value.
  • the air-fuel ratio feedback correction coefficient ⁇ becomes the lower threshold value from time t2 in FIG. 4, and is limited so as not to become a smaller value.
  • the purge rate does not change from the value corresponding to the lower threshold value from time t2 in FIG. 4. Note that the purge rate is equal to or greater than the judgment threshold value prior to time t2. In the second embodiment, when the purge rate becomes equal to or greater than the judgment threshold value, it is determined that the air-fuel ratio feedback correction coefficient ⁇ has changed due to purging.
  • Time t3 in FIG. 4 is the timing when the throttle is fully opened and the intake pressure (intake manifold pressure) in the intake manifold 7 rises to a value close to atmospheric pressure, causing the purge rate to become smaller than the second purge threshold, which is smaller than the judgment threshold.
  • the second purge threshold is greater than the first purge threshold. Note that the intake pressure in the intake manifold 7 is greater than the pressure threshold due to the throttle being fully opened prior to time t3.
  • the intake pressure in the intake manifold 7 becomes greater than the pressure threshold and the purge rate becomes less than the second purge value threshold, it is determined that purge cut has been performed.
  • Time t4 in FIG. 4 is the timing when the above-mentioned predetermined time has elapsed from time t3, and is the timing when the above-mentioned correction coefficient initialization process is performed.
  • the air-fuel ratio feedback correction coefficient ⁇ is suddenly returned toward the above-mentioned reference value at the timing of time t4 in FIG. 4.
  • the characteristic line S1 shown by a dashed line in FIG. 2 shows the change in the air-fuel ratio feedback correction coefficient ⁇ when the air-fuel ratio feedback correction coefficient ⁇ is not suddenly returned to the above-mentioned reference value at the timing of time t4.
  • the characteristic line S2 shown by a dashed line in FIG. 2 shows the change in the air-fuel ratio of the internal combustion engine when the air-fuel ratio feedback correction coefficient ⁇ changes as in the characteristic line S1.
  • the air-fuel ratio of the internal combustion engine is prevented from fluctuating toward the lean side by suddenly returning the air-fuel ratio feedback correction coefficient ⁇ to the reference value at time t4.
  • FIG. 5 is a flowchart showing the flow of control of the internal combustion engine in the second embodiment.
  • step S11 it is determined whether or not the purge has been cut off from a state in which the air-fuel ratio feedback correction coefficient ⁇ has deviated from the reference value due to the purge gas.
  • the purge rate and the air-fuel ratio feedback correction coefficient ⁇ are used to determine whether or not the air-fuel ratio feedback correction coefficient ⁇ has deviated from the reference value due to the flow of purge gas into the intake passage 2. If the purge rate is equal to or greater than the determination threshold and the air-fuel ratio feedback correction coefficient ⁇ is equal to or less than the correction coefficient threshold, it is determined that the air-fuel ratio feedback correction coefficient ⁇ has deviated from the reference value due to the purge gas.
  • step S12 it is determined whether the purge rate has suddenly decreased. In other words, in step S12, if the purge rate has decreased at a rate of change equal to or greater than a preset threshold value for the rate of change, it is determined that a stepwise decrease in the purge rate has occurred.
  • step S13 it is determined whether the purge rate is less than the second purge threshold. If the purge rate is less than the second purge threshold, the process proceeds to step S14, where the delay timer starts counting. The delay timer measures the predetermined time.
  • step S15 it is determined whether the predetermined time has elapsed since the delay timer started counting. If the predetermined time has elapsed, the process proceeds to step S16.
  • step S16 a correction coefficient initialization process is performed to return the air-fuel ratio feedback correction coefficient ⁇ to a reference value.
  • the internal combustion engine of the second embodiment can bring the air-fuel ratio feedback correction coefficient ⁇ closer to a value that corresponds to the actual air-fuel ratio, suppressing the fluctuation (deterioration) of the air-fuel ratio and preventing the air-fuel ratio from fluctuating significantly toward the lean side.
  • the internal combustion engine of the second embodiment performs the correction coefficient initialization process at a timing delayed by the above-mentioned predetermined time, which makes it possible to prevent the air-fuel ratio from becoming rich.
  • the internal combustion engine of the second embodiment determines that the air-fuel ratio feedback correction coefficient has deviated from the reference value due to the purge gas when the purge rate is equal to or greater than the determination threshold value, and therefore can prevent the correction coefficient initialization process from being performed when the air-fuel ratio feedback correction coefficient ⁇ deviates from the reference value due to factors other than the purge gas.
  • the internal combustion engine of the second embodiment performs the above correction coefficient initialization process when the air-fuel ratio feedback correction coefficient ⁇ is equal to or less than the above correction coefficient threshold value and the air-fuel ratio of the internal combustion engine exceeds the above lean limit value due to a stepwise decrease in the purge rate.
  • the internal combustion engine of the second embodiment can prevent the air-fuel ratio from being adversely affected by the unnecessary implementation of the correction coefficient initialization process.
  • the internal combustion engine of the second embodiment performs the correction coefficient initialization process when the intake pressure in the intake manifold 7 is equal to or higher than the pressure threshold, so that the correction coefficient initialization process can be avoided due to factors other than a decrease in the intake pressure (negative pressure).
  • the internal combustion engine of the second embodiment determines that the purge has been cut when the purge rate falls below the second purge threshold. Therefore, the internal combustion engine of the second embodiment can avoid performing the correction coefficient initialization process until the amount of purge gas has decreased to a level that does not affect the air-fuel ratio.
  • the internal combustion engine of the second embodiment performs the correction coefficient initialization process when the purge rate decreases at a rate of change equal to or greater than the threshold rate of change and the amount of purge gas supplied to the intake passage 2 becomes a small amount equal to or less than a predetermined amount. Whether the amount of purge gas supplied is a small amount equal to or less than a predetermined amount is determined by whether the purge rate is less than the second purge threshold. In other words, the internal combustion engine of the second embodiment determines that the amount of purge gas supplied to the intake passage 2 is a small amount less than a predetermined amount when the purge rate becomes less than the second threshold.
  • the correction coefficient initialization process is performed to prevent the air-fuel ratio from fluctuating significantly toward the lean side.
  • the internal combustion engine of the second embodiment can avoid performing the correction coefficient initialization process until the amount of purge gas supplied becomes small.
  • the return amount of the air-fuel ratio feedback correction coefficient ⁇ in the correction coefficient initialization process may be corrected according to the atmospheric pressure.
  • the lower the atmospheric pressure the more evaporated fuel there is in the purge gas. Therefore, when performing the correction coefficient initialization process, instead of returning the air-fuel ratio feedback correction coefficient ⁇ to the reference value, the coefficient may be corrected so that the return amount toward the reference value decreases as the atmospheric pressure increases.
  • the air-fuel ratio feedback correction coefficient ⁇ may be returned to be smaller than the reference value as the atmospheric pressure increases.
  • the return amount of the air-fuel ratio feedback correction coefficient ⁇ in the correction coefficient initialization process may be corrected according to the fuel temperature in the fuel tank 20.
  • the air-fuel ratio feedback correction coefficient ⁇ may be returned to be smaller than the reference value as the fuel temperature is lower.
  • the above-mentioned embodiments relate to a method for controlling an internal combustion engine and a control device for an internal combustion engine.

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  • Chemical & Material Sciences (AREA)
  • Combustion & Propulsion (AREA)
  • Mechanical Engineering (AREA)
  • General Engineering & Computer Science (AREA)
  • Supplying Secondary Fuel Or The Like To Fuel, Air Or Fuel-Air Mixtures (AREA)
  • Electrical Control Of Air Or Fuel Supplied To Internal-Combustion Engine (AREA)

Abstract

Selon l'invention, un moteur à combustion interne (1) est commandé par rétroaction à l'aide d'un coefficient de correction de rétroaction de rapport air-carburant de sorte que le rapport air-carburant devient un rapport air-carburant théorique. Lorsque le coefficient de correction de rétroaction de rapport air-carburant (α) est une valeur qui s'est écartée d'une valeur de référence prescrite en raison du gaz de purge qui contient du carburant évaporé provenant d'un réservoir de carburant (20), le moteur à combustion interne (1) met en œuvre un processus d'initialisation de coefficient de correction pour renvoyer le coefficient de correction de rétroaction de rapport air-carburant vers la valeur de référence lorsqu'une diminution progressive du taux de purge se produit. Ainsi, le moteur à combustion interne (1) peut amener le coefficient de correction de rétroaction de rapport air-carburant (α) proche d'une valeur correspondant au rapport air-carburant réel et peut supprimer une fluctuation du rapport air-carburant.
PCT/JP2023/020908 2023-06-06 2023-06-06 Procédé de commande de moteur à combustion interne et dispositif de commande de moteur à combustion interne Pending WO2024252505A1 (fr)

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PCT/JP2023/020908 WO2024252505A1 (fr) 2023-06-06 2023-06-06 Procédé de commande de moteur à combustion interne et dispositif de commande de moteur à combustion interne

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PCT/JP2023/020908 WO2024252505A1 (fr) 2023-06-06 2023-06-06 Procédé de commande de moteur à combustion interne et dispositif de commande de moteur à combustion interne

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Citations (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPS5677545A (en) * 1979-11-30 1981-06-25 Nissan Motor Co Ltd Controller for vaporized fuel in internal combustion engine with turbo supercharger
JPH05202817A (ja) * 1992-01-28 1993-08-10 Daihatsu Motor Co Ltd 空燃比制御方法
JPH07305645A (ja) * 1994-05-09 1995-11-21 Nissan Motor Co Ltd エンジンの空燃比制御装置
JP2008014280A (ja) * 2006-07-10 2008-01-24 Toyota Motor Corp 内燃機関の空燃比制御装置
JP2012117415A (ja) * 2010-11-30 2012-06-21 Daihatsu Motor Co Ltd 内燃機関の制御装置

Patent Citations (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPS5677545A (en) * 1979-11-30 1981-06-25 Nissan Motor Co Ltd Controller for vaporized fuel in internal combustion engine with turbo supercharger
JPH05202817A (ja) * 1992-01-28 1993-08-10 Daihatsu Motor Co Ltd 空燃比制御方法
JPH07305645A (ja) * 1994-05-09 1995-11-21 Nissan Motor Co Ltd エンジンの空燃比制御装置
JP2008014280A (ja) * 2006-07-10 2008-01-24 Toyota Motor Corp 内燃機関の空燃比制御装置
JP2012117415A (ja) * 2010-11-30 2012-06-21 Daihatsu Motor Co Ltd 内燃機関の制御装置

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