JP2011064178A - Intake control device for internal combustion engine - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an intake control device for an internal combustion engine, capable of diagnosing the malfunctioning of a pulsation damping device. <P>SOLUTION: The intake control device for the internal combustion engine includes an air flow meter 50 provided in an intake pipe 12 communicated with a combustion chamber 11 of an engine 10 for detecting the pulsation of air sucked into the combustion chamber 11, a throttle position sensor 31 and a crank position sensor 33 for detecting the operating condition of the engine 10, a resonator 20 as a device for damping the pulsation in the intake pipe 12, the resonator 20 having an adjustable resonance frequency, and an engine control device 40 for controlling the resonance frequency of the resonator 20 in accordance with the outputs of the sensors 31, 33. The engine control device 40 determines whether the resonator 20 is normally actuated or not, in accordance with the pulsation in the intake pipe 12 detected by the air flow meter 50 under the condition of controlling the resonance frequency of the resonator 20 and the pulsation as a criterion set depending on the operating condition of the engine 10. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to an intake air control device for an internal combustion engine including a pulsation damping device that attenuates pulsation in an intake pipe communicating with a combustion chamber by resonance.

  Conventionally, in order to improve the efficiency of intake into the combustion chamber of the internal combustion engine, or to reduce the noise associated with intake of the internal combustion engine, it is connected to the intake pipe communicating with the combustion chamber, and the pulsation in the intake pipe is resonated. Attenuating resonators are known. Some of these resonators can adjust the resonance frequency.

  For example, Patent Document 1 discloses an intake air amount of an internal combustion engine provided with a resonator tank having a structure in which an internal capacity provided in the intake passage of the internal combustion engine can be changed, and a control device that controls the change of the tank capacity. A control device is disclosed. The control device disclosed in Patent Document 1 detects the operating state of the internal combustion engine by a throttle sensor, a crank angle sensor, or the like, and changes the capacity of the resonator tank based on these outputs. By changing the capacity, the resonance frequency of the resonator is adjusted to attenuate the pulsation in the intake pipe.

  Further, for example, Patent Document 2 includes a passage member that forms an intake passage of an internal combustion engine, and a resonator that forms a volume portion branched from the passage member, and the natural frequency of a vibration portion that covers an end portion of the volume portion. An intake noise reduction device for controlling the air pressure by magnetic force is disclosed. In the device disclosed in Patent Document 2, the natural frequency of the resonator vibration portion is changed based on the rotational speed of the crankshaft. As described above, the resonance frequency of the resonator is adjusted by changing the natural frequency of the vibration unit in accordance with the rotational speed of the crankshaft, so that the pulsation generated in the intake pipe is effectively attenuated.

JP-A-6-307248 JP 2007-187081 A

  In the intake air amount control device disclosed in Patent Document 1 and the intake sound reduction device disclosed in Patent Document 2, the resonance of the resonator is controlled by the control of the control means based on the outputs of various sensors that detect the operation status of the internal combustion engine. The frequency to be adjusted is adjusted. However, it is not determined whether or not the actual resonance frequency by the adjusted resonator can correspond to the frequency of the intake pulsation occurring in the intake pipe in the operating state of the internal combustion engine. Therefore, it is possible to diagnose a state in which the resonance frequency of the resonator is not adjusted to correspond to the frequency of pulsation generated in the intake pipe due to a failure of the resonator, aging, manufacturing tolerance, etc. could not.

  The present invention has been made in view of the above problems, and an object thereof is to provide an intake control device for an internal combustion engine capable of diagnosing an abnormality in a pulsation damping device.

  To achieve the above object, according to the first aspect of the present invention, in the intake pipe communicating with the combustion chamber of the internal combustion engine, pulsation detecting means for detecting the pulsation of the air sucked into the combustion chamber, and the operation of the internal combustion engine A driving state detecting means for detecting a state, a pulsation damping device which is connected to the intake pipe and attenuates the pulsation in the intake pipe by resonance, the resonance frequency can be adjusted, and an output of the operating state detecting means Based on the control means for controlling the resonance frequency of the pulsation attenuator, the pulsation attenuator is controlled by the control means, and the pulsation in the intake pipe by the output of the pulsation detector and the output of the operating state detector And an operating state determining means for determining whether or not the pulsation damping device is operating normally on the basis of the reference pulsation set in the above, and intake control of the internal combustion engine, And location.

  According to the present invention, the frequency at which the pulsation damping device resonates is adjusted by the control of the control means based on the output of the operating state detection means. In the intake pipe to which the pulsation attenuator having the adjusted frequency is connected, the pulsation of the intake air subjected to the attenuating action of the pulsation attenuator is detected by the pulsation detecting means and output to the operating state determining means. The operating state determination unit is configured to reduce the pulsation based on the actual pulsation in the intake pipe and the reference pulsation set based on the output of the operating state detection unit while the pulsation damping device is controlled by the control unit. It can be determined whether or not the damping action by the device is obtained, and by extension, whether or not the pulsation damping device is operating normally. Therefore, the intake control device can diagnose that the pulsation damping device is abnormal.

  According to the second aspect of the present invention, the operating state determination unit acquires the amplitude of the pulsation in the intake pipe from the output of the pulsation detection unit, and the pulsation amplitude is a threshold value set based on the reference pulsation amplitude. When the amplitude is larger than the amplitude, it is determined that the pulsation damping device is not in a normally operating state.

  As in the present invention, the operating state determining means is configured so that the pulsation attenuating device operates normally by the amplitude of the pulsation generated in the intake pipe and the threshold amplitude set based on the reference pulsation amplitude. You may determine whether it is in a state. In this case, the reference pulsation amplitude is used to set the threshold value for determining that the pulsation damping device is not operating normally. As described above, the intake control device can diagnose that the pulsation damping device is abnormal when the actual pulsation amplitude is larger than the threshold amplitude. Here, the pulsation detected by the pulsation detecting means when the pulsation attenuating device is operating normally is used as a reference pulsation, and a value obtained by multiplying the amplitude of the pulsation by a predetermined coefficient or a predetermined value for the amplitude. It is desirable to set a value obtained by adding as the threshold amplitude.

  In the invention according to claim 3, the operating state determination means acquires the frequency of the pulsation in the intake pipe from the output of the pulsation detection means, and the pulsation frequency is outside a predetermined frequency band including the reference pulsation frequency. In some cases, it is determined that the pulsation damping device is not in a normally operating state.

  As in the present invention, the operating state determination means determines whether or not the pulsation damping device is operating normally based on the frequency of the pulsation waveform generated in the intake pipe and the reference pulsation frequency. You may judge. In this case, when the actual pulsation frequency is outside a predetermined frequency band including the reference pulsation frequency, the operating state determination means determines that the operating state is not in a normal operating state. Here, it is desirable that the reference pulsation frequency is set to the pulsation frequency detected by the pulsation detecting means when the pulsation attenuator is operating normally.

  In the invention according to claim 4, the operating state determination means acquires the phase of the pulsation in the intake pipe from the output of the pulsation detection means, and the phase difference between the phase of the pulsation and the phase of the reference pulsation is predetermined. When the phase difference is larger than the above, it is determined that the pulsation damping device is not in a normally operating state. As in the present invention, the operating state determining means determines whether or not the pulsation attenuator is operating normally based on the phase difference between the pulsation phase in the intake pipe and the reference pulsation phase. May be. In this case, when the phase difference between the actual pulsation and the reference pulsation exceeds a predetermined phase difference, the operating state determining means determines that the operating state is not in a normally operating state. The reference pulsation phase is preferably set to the pulsation phase detected by the pulsation detecting means when the pulsation attenuator is operating normally. The predetermined phase difference determined in advance may be constant or may be changed according to the operating state of the internal combustion engine.

  The invention according to claim 5 further includes a steady state determination unit that determines whether or not the pulsation damping device is in a steady state, and the operation state determination unit is based on the determination that the operation state determination unit is in a steady state. It is characterized by determining whether the pulsation damping device is operating normally. By determining whether or not the pulsation damping device is operating normally when the pulsation damping device is in a steady state as in the present invention, the accuracy of the determination by the operating state determining means can be improved. Therefore, the intake control device can reliably diagnose abnormality of the pulsation damping device.

  Then, as in the sixth aspect of the invention, the steady state determination means determines whether or not the pulsation damping device is in a steady state and is calculated by the control means based on the output of the operating state detection means. It is desirable to use a resonant frequency. If the change in the target resonance frequency within a predetermined time has changed within a predetermined range, the pulsation damping device controlled by the control means so that the resonance frequency becomes the target resonance frequency is in a steady state. This is because it is estimated that there is.

  In the seventh aspect of the invention, the control means feedback-controls the pulsation attenuation device so that the resonance frequency of the pulsation attenuation device approximates the target resonance frequency calculated based on the output of the operating state detection means. Features. As in the present invention, when the pulsation attenuator is feedback-controlled by the control means, the resonance frequency of the pulsation attenuator is accurately approximated to the target resonance frequency calculated based on the output of the operating state detection means. Adjusted. As described above, when used in a pulsation attenuating device in which the frequency is adjusted accurately during normal operation, the operating state determination means can easily determine the state of the pulsation attenuating device that is not operating normally. Therefore, the intake control device can reliably diagnose that the pulsation damping device is abnormal.

  Then, as in the eighth aspect of the invention, the control is performed so that the difference between the value relating to the pulsation waveform corresponding to the target resonance frequency and the value relating to the pulsation waveform of the intake pipe based on the output of the pulsation detecting means decreases. It is desirable that the means feedback-controls the pulsation damping device. As described above, by adopting an embodiment in which the feedback control is performed based on the output of the pulsation detecting means, a configuration used for diagnosing abnormality of the pulsation attenuating device can be used. Therefore, the intake control device is not complicated. The values related to the pulsation waveform include the amplitude, frequency (wavelength), phase, and the like of the waveform.

  In the invention according to claim 9, the pulsation detecting means has an air flow meter for measuring the flow rate of the air flowing in the intake pipe, and detects the waveform of the pulsation in the intake pipe based on the output measured by the air flow meter. It is characterized by. According to the present invention, the flow rate of the intake air flowing through the intake pipe varies due to the pulsation in the intake pipe. Therefore, the pulsation in the intake pipe can be detected by measuring the fluctuation of the flow rate of the air flowing in the intake pipe with the air flow meter. Therefore, by using an air flow meter having an existing configuration as the pulsation detecting means, it is possible to realize an intake control device capable of diagnosing that there is an abnormality in the pulsation attenuation device while suppressing the complexity of the configuration.

It is a figure which shows the structure of the whole engine control system provided with the intake control device by this invention. It is a figure for demonstrating the effect of a resonator. In 1st embodiment of this invention, it is a flowchart which shows the control flow for controlling the frequency which a resonator resonates. In 1st embodiment of this invention, it is a flowchart which shows the diagnostic flow for diagnosing abnormality of a resonator. In the second embodiment of the present invention, it is a flowchart showing a control flow for controlling the resonant frequency of the resonator.

  Hereinafter, a plurality of embodiments of the present invention will be described with reference to the drawings. In addition, the overlapping description is abbreviate | omitted by attaching | subjecting the same code | symbol to the corresponding component in each embodiment.

(First embodiment)
FIG. 1 is a diagram for explaining the overall configuration of the engine 10 and the control system of the engine 10. The engine 10 is configured by members or mechanisms such as a piston, an engine block, a crankshaft 16, a variable valve timing mechanism 18, an intake pipe 12, and a resonator 20. The engine 10 is integrally controlled by the engine control device 40. The intake control device 100 according to the first embodiment of the present invention includes a resonator 20, an engine control device 40, and the like.

  The intake pipe 12 communicates with each of the combustion chambers 11 formed in the engine 10. The intake pipe 12 is provided with an air cleaner 12 a, a resonator 20, an air flow meter 50, a throttle body 14, a surge tank 12 b, and the like in this order from the upstream side opposite to the combustion chamber 11. The air cleaner 12 a is configured to remove foreign substances in the air sucked into the combustion chamber 11, and includes a filter formed of paper or fiber, and a cleaner box for fixing the filter to the intake pipe 12. Have.

  The resonator 20 communicates with the intake pipe 12 on the downstream side of the air cleaner 12a, and is a device that attenuates pulsation in the intake pipe 12 by resonance. The resonator 20 includes a container body 21, a connecting pipe 23, a movable lid body 25, an actuator 27, an actuator support portion 28, and the like. The container body 21 is a bottomed container that forms a resonance chamber 21 a together with the movable lid body 25. The bottom of the container body 21 is connected to the intake pipe 12 via a tubular connection pipe 23 having a predetermined inner diameter and length. Thereby, the resonance chamber 21 a and the space in the intake pipe 12 are communicated with each other via the connection pipe 23. The movable lid 25 is housed inside the container body 21 and is slidable along the inner peripheral wall of the container body 21. The actuator 27 is a DC motor that is electrically connected to the engine control device 40, and includes a rotating shaft 27 a that rotates under the control of the engine control device 40. The rotating shaft 27 a is provided with a male screw portion and is screwed with a female screw portion provided on the movable lid 25. The actuator 27 is supported on the container body 21 via the actuator support portion 28. With the above configuration, the actuator 27 rotates the rotating shaft 27 a under the control of the engine control device 40 to move the movable lid 25 to a desired position in the container body 21. Due to the movement of the movable cover 25, the volume of the resonance chamber 21a changes.

  The air flow meter 50 is a sensor that is provided on the downstream side of the resonator 20 and measures the flow rate of air flowing through the intake pipe 12. The air flow meter 50 is electrically connected to the engine control device 40 and outputs a detection result to the engine control device 40. In addition, the air flow meter 50 in the first embodiment is a high-response type having a sampling frequency sufficiently high with respect to the frequency of intake pulsation, and can detect the waveform of the intake pulsation.

  The throttle body 14 is a device that is provided on the downstream side of the air flow meter 50 and adjusts the amount of air taken into the combustion chamber 11. The throttle body 14 has a throttle valve 14a, a throttle motor 15 and a throttle position sensor 31 that detect the amount of operation of the accelerator pedal by the driver with an accelerator position sensor and open and close according to the detection result. The throttle motor 15 is a DC motor, for example, and is electrically connected to the engine control device 40, and its operation is controlled based on detection by an accelerator position sensor. The throttle motor 15 drives the throttle valve 14a under the control of the engine control device 40, and opens the throttle valve 14a to a desired opening. The throttle position sensor 31 is electrically connected to the engine control device 40, detects the opening of the throttle valve 14a, and outputs it to the engine control device 40.

  The surge tank 12 b is provided on the downstream side of the throttle body 14 and communicates with each of the plurality of combustion chambers 11. The surge tank 12b has a configuration for making the amount of air sucked into each of the plurality of combustion chambers 11 uniform.

  The engine control apparatus 40 is configured mainly with a microcomputer, and maps and mathematical formulas for calculating values used for various controls in a built-in storage medium such as a ROM or a flash memory, and these Stores programs to be executed when calculating values. These control programs and control maps include those used for controlling the resonator 20 described later and diagnosing abnormalities.

  The engine control device 40 is connected to the water temperature sensor 36, the knock sensor 37, the exhaust gas sensor 38, the crank position sensor 33, and the like for detecting the operating state of the engine 10, together with the throttle position sensor 31 and the air flow meter 50 described above. ing. The crank position sensor 33 is an electromagnetic pickup sensor, and has a plurality of radial protrusions. The crank position sensor 33 measures the increase or decrease in magnetic flux caused by a timing rotor that rotates integrally with the crankshaft 16. Detect the phase. Further, the engine control device 40 is electrically connected to the variable valve timing mechanism 18 together with the throttle motor 15 and the actuator 27, and controls them. The variable valve timing mechanism 18 is a mechanism that varies the relative phase between the intake side camshaft (not shown) and the crankshaft 16, and the opening / closing timing (hereinafter referred to as “valve”) of the intake valve 19 driven by the camshaft. Timing) can be adjusted. The engine control device 40 controls the variable valve timing mechanism 18 to adjust the valve timing by changing the relative phase described above, for example, according to the rotational speed of the engine 10 and the opening of the throttle valve 14a.

  Further, the engine control device 40 has functions of a band pass filter and a fast Fourier transform for processing the output detected by the air flow meter 50. The band-pass filter eliminates or attenuates vibration components outside a specific frequency band. By passing the output detected by the air flow meter 50 through a bandpass filter, vibration components other than the intake pulsation included in the output can be eliminated or reduced. Therefore, the amplitude and phase of the intake pulsation are accurately acquired by the engine control device 40 by the output passing through the band pass filter. Further, the engine control device 40 can acquire the frequency of intake pulsation from the output detected by the air flow meter 50 by the function of the fast Fourier transform.

  In the configuration as described above, the action of the resonator 20 resonating with the pulsation of the air flowing in the intake pipe 12 to attenuate the pulsation and the effect obtained by the engine 10 by this action will be described below.

  The resonator 20 can resonate the air in the resonance chamber 21a with respect to vibration having a frequency determined by the length and inner diameter of the connection pipe 23 and the volume of the resonance chamber 21a. Due to this resonance, air reciprocating between the resonance chamber 21 a and the inside of the intake pipe 12 causes intense friction with the inner peripheral wall of the connection pipe 23 when passing through the connection pipe 23. Therefore, the pulsation in the intake pipe 12 is attenuated by depriving energy by heat generated by friction. And the resonator 20 is set as the structure which can adjust the frequency to resonate by changing the volume of the resonance chamber 21a. Therefore, the control of matching the resonance frequency of the resonator 20 with the frequency of the intake pulsation in the intake pipe 12 that changes depending on the operation state of the engine 10 is sequentially performed, so that the intake pulsation is attenuated regardless of the operation state of the engine 10. Is possible. The noise generated by the intake pulsation can be reduced by the damping action of the resonator 20 described so far. In addition, due to the damping action, the air density in the intake pipe 12 is smoothed, so that fluctuations in the amount of air sucked into the combustion chamber 11 due to operating conditions can be eliminated.

  The effect of reducing the noise generated by the intake pulsation of the resonator 20 will be described in more detail with reference to FIG. In the intake pipe 12, a pulsation having a large amplitude occurs at a specific frequency according to the length and inner diameter of the intake pipe 12 and the operating state of the engine 10. (See FIG. 2, solid line). This pulsation with a large amplitude is a main factor of noise accompanying intake. Therefore, the resonance frequency of the resonator 20 is adjusted so as to approximate the frequency of pulsation occurring in the intake pipe 12 (see the target resonance frequency in FIG. 2). As a result, the resonator 20 can attenuate the pulsation by causing the air in the resonance chamber 21a to resonate with the pulsation in the intake pipe 12 (see the broken line in FIG. 2). When the resonance frequency of the resonator 20 is not close to the target resonance frequency, the damping action by the resonator 20 is limited (see the dotted line in FIG. 2).

<Resonator feedback control>
In the resonator 20 described above, the resonance frequency is feedback-controlled by the engine control device 40. Hereinafter, a control flow in which the engine control device 40 performs feedback control on the resonance frequency of the resonator 20 according to the operating state of the engine 10 will be described with reference to FIG. Note that the control flow shown in FIG. 3 is started when the engine 10 is started, and is repeatedly executed until the engine 10 is stopped.

  In step S101, the engine control device 40 detects the operating state of the engine 10. Specifically, the crank position sensor 33 detects the rotational speed and phase of the crankshaft 16, and the throttle position sensor 31 detects the opening of the throttle body 14 indicating the load state of the engine 10. In addition, the engine control device 40 acquires the valve timing adjusted by the variable valve timing mechanism 18 together.

  In step S102, the engine control device 40 calculates a target resonance frequency of the resonator 20 corresponding to the operating state of the engine 10 acquired in step S101. Specifically, the engine control device 40 calculates the target resonance frequency at the rotational speed, the load state, and the valve timing acquired in step S101, using the map stored in the storage medium. It should be noted that a mathematical formula for calculating the target resonance frequency from these operating states may be stored in a storage medium in advance, and the engine control device 40 may perform processing for calculating the target resonance frequency using the mathematical formula. In step S103, the resonance frequency of the resonator 20 is controlled by driving the actuator 27 so that the calculated target resonance frequency is obtained.

  In step S104, when the resonance frequency of the resonator 20 is correctly adjusted to the target resonance frequency calculated in step S102, a value related to pulsation in the intake pipe 12 detected by the air flow meter 50 is calculated as a target pulsation level. To do. The pulsation level is, for example, at least one of the amplitude, frequency (wavelength), and phase of the pulsation waveform. In the first embodiment, the engine control device 40 calculates, as the target pulsation level, the phase of pulsation (hereinafter referred to as target phase) generated in the intake pipe 12 when the resonance frequency of the resonator 20 is correctly adjusted. This target phase is a phase obtained by associating the angular position of the crankshaft 16 (hereinafter referred to as crank angle) detected by the crank position sensor 33 with the pressure in the intake pipe 12.

  In step S105, the phase (actual phase) of the actual pulsation occurring in the intake pipe 12 is detected. The waveform of the actual phase is acquired by associating the crank angle detected by the crank position sensor 33 with the pressure in the intake pipe 12 detected by the air flow meter 50.

  In step S106, the control amount of the resonator 20 is calculated based on the target phase and the actual phase acquired in steps S104 and S105. Specifically, the engine control device 40 calculates a phase difference between the target phase and the actual phase as a difference. Then, the engine control device 40 calculates a control amount of the resonator 20 corresponding to the difference and the operating state of the engine 10 acquired in step S101, using a map or a mathematical formula stored in advance in the storage medium. In step S107, based on the control amount calculated in step S106, the engine control device 40 drives the actuator 27 to adjust the resonant frequency of the resonator 20. By this adjustment, the difference between the target phase and the actual phase is reduced.

  With the above processing, the control flow ends. As described above, the resonator 20 is feedback-controlled by the engine control device 40, so that the resonance frequency of the resonator 20 is accurately adjusted so as to effectively attenuate the pulsation in the intake pipe 12 according to the operating state of the engine 10. Adjusted to

<Resonator abnormality diagnosis>
Next, a diagnosis flow in which the intake control device 100 diagnoses the abnormality of the resonator 20 described so far will be described based on FIG. 4 with reference to FIG. The diagnosis flow is started when the engine 10 is started in the same manner as the control flow of the resonator 20 described above, and is repeatedly executed until the engine 10 is stopped. This diagnosis flow determines that the resonator 20 is not in a normal working state when the resonance frequency of the resonator 20 is not approximated to the target frequency even in a state adjusted by feedback control. Specifically, when the resonator 20 is fixed to the container body 21 of the movable lid 25, the operation failure of the actuator 27, or the like, it is diagnosed that the resonator 20 is abnormal.

  In step S111, the engine control device 40 detects the operating state of the engine 10. In step S112, the engine control device 40 first calculates a target resonance frequency of the resonator 20 according to the operating state detected in step S111. Then, the transition of the calculated target resonance frequency within a predetermined time is recorded. Here, these steps S111 and S112 include processing similar to steps S101 and S102 performed in the feedback control. Therefore, the engine control device 40 may omit the process of step S111 and may perform the process of step S112 using the target resonance frequency calculated in step S102.

  In step S113, it is determined whether or not the resonator 20 is in a steady state. If the change in the target resonance frequency recorded in step S112 within a predetermined time has changed within a predetermined range, the engine control device 40 determines that the resonator 20 is in a steady state. In this case, the diagnosis flow moves to step S114. On the other hand, when the change of the target resonance frequency is out of the predetermined range, the diagnosis flow is ended.

  In step S114, the engine control device 40 calculates an abnormality determination level serving as a threshold for determining whether or not the resonator 20 is operating normally. Here, in the first embodiment, the determination is performed based on the amplitude of the intake pulsation. The engine control device 40 calculates the abnormality determination level of the pulsation amplitude corresponding to the operating state of the engine 10 using a map or a mathematical formula stored in advance in the storage medium. This abnormality determination level of the amplitude is determined based on the reference pulsation amplitude, with the pulsation detected by the airflow meter 50 as the reference pulsation during normal operation of the resonator 20. Specifically, a value obtained by adding a predetermined value to a reference pulsation amplitude or a value obtained by multiplying a predetermined coefficient is set as the amplitude abnormality determination level (see FIG. 2). These predetermined values and predetermined constants may be set as appropriate.

  In step S115, the amplitude of the pulsation is detected from the pulsation output in the intake pipe 12 measured by the air flow meter 50, and is acquired as the intake pulsation level. In step S116, a determination is made based on the intake pulsation level detected in step S115 and the abnormality determination level calculated in step S114. In step S116, when the intake pulsation level is higher than the abnormality determination level, that is, when the actual pulsation amplitude is larger than the threshold value set based on the reference pulsation, the diagnostic flow proceeds to step S117. . On the other hand, when the intake pulsation level is equal to or lower than the abnormality determination level in step S116, the diagnosis flow ends.

  In step S117, it is diagnosed that the resonator 20 is not operating normally (abnormal). Based on this diagnosis, the engine control device 40 displays an indicator indicating an abnormality of the intake control device 100 on, for example, a display device installed in front of the driver.

  According to the first embodiment described so far, the pulsation of the intake air subjected to the damping action by the resonator 20 is detected by the air flow meter 50 and output to the engine control device 40. As a result, the engine control device 40 can acquire the actual pulsation in the intake pipe 12. In addition, the engine control device 40 acquires the operating state of the engine 10 and acquires a reference pulsation that is set in advance according to the operating state. As described above, the engine control device 40 determines whether or not the damping action by the resonator 20 is obtained, and thus whether or not the resonator 20 is operating normally, based on the actual pulsation and the reference pulsation. can do.

  In addition, in the first embodiment, the pulsation in the intake pipe 12 when the resonator 20 is operating normally is set as a reference pulsation, and a value obtained by adding a predetermined value to the amplitude of the pulsation is set as an abnormality determination level. ing. Thus, by using the pulsation during normal operation of the resonator 20 as a reference pulsation and using it for setting the abnormality determination level, the accuracy of determination as to whether or not the resonator 20 is operating normally is improved. Can do.

  In the first embodiment, the engine control device 40 determines whether or not the resonator 20 is in a steady state, and determines the operating state of the resonator 20 when it is determined as a steady state. For determining whether or not the resonator 20 is in a steady state, it is desirable to use the target resonance frequency calculated by the engine control device 40. This is because the resonator 20 whose frequency is controlled to approximate the target resonance frequency can be estimated to be in a steady state if the change in the target resonance frequency is within a predetermined range. As described above, only when the resonator 20 is in a steady state, it is possible to further improve the accuracy of the determination by determining whether or not the resonator 20 is operating normally. .

  Furthermore, in the first embodiment, it is determined whether or not the resonator 20 whose frequency is accurately adjusted by feedback control is operating normally. Thus, if the normal frequency adjustment is accurate, it becomes easy to determine the state of operation of the resonator 20 that is not normal. Therefore, the engine control device 40 can accurately determine whether or not the resonator 20 is operating normally.

  As described above, the intake control device 100 can diagnose that the resonator 20 is abnormal.

  In addition, in the first embodiment, the feedback control of the resonator 20 is performed based on the output of the air flow meter 50, so that the configuration used for diagnosing the abnormality of the resonator 20 is directly used for the feedback control. Therefore, the intake control device 100 is not complicated by the feedback control. In addition, since the air flow meter 50 has an existing configuration in the general engine 10, the use of the air flow meter 50 for detection of pulsation can reliably avoid complication of the intake control device 100.

  In the first embodiment, the air flow meter 50 is included in the “pulsation detecting means” described in the claims, the throttle position sensor 31 and the crank position sensor 33 are included in the “driving state detecting means” described in the claims, and the resonator 20 is In the “pulsation damping device” described in the claims, the engine control device 40 is “control means”, “operation state determination means”, “steady state determination means”, and the engine 10 is “internal combustion engine” described in the claims. Each corresponds.

(Second embodiment)
The second embodiment of the present invention is a modification of the first embodiment. In the second embodiment, the engine control device 40 does not use feedback control for control to adjust the resonant frequency of the resonator 20. Hereinafter, the control flow of the resonator 20 by the engine control device 40 of the second embodiment will be described based on FIG. 5 with reference to FIG.

  In step S201, as in step S101 of the first embodiment, the engine control device 40 detects the operating state such as the rotational speed, load state, and valve timing of the engine 10. In step S202, the engine control device 40 calculates the control amount of the resonator 20 corresponding to the operating state of the engine 10 detected in step S201 using a map or formula stored in advance in the storage medium. In step S203, based on the calculated control amount, the engine control device 40 drives the actuator 27 to adjust the resonant frequency of the resonator 20. Thus, the control flow ends. The control flow shown in FIG. 5 is started when the engine 10 is started, and is repeatedly executed until the engine 10 is stopped.

  Even in the form in which feedback control is not used for controlling the frequency of the resonator 20 as described above, the abnormality diagnosis of the resonator 20 can be performed by the same diagnosis flow as in the first embodiment. Therefore, the intake control device according to the present invention can diagnose that there is an abnormality in the resonator 20 regardless of the method of controlling the resonator 20 by the engine control device 40.

(Third embodiment)
The third embodiment of the present invention is another modification of the first embodiment, and the resonance frequency of the resonator 20 is feedback-controlled as in the first embodiment. In the third embodiment, whether or not the resonator 20 is operating normally is determined based on the amplitude and phase of the intake pulsation. Hereinafter, based on FIG. 4, the diagnosis flow of the third embodiment will be described with reference to FIG. In addition, the process similar to 1st embodiment is implemented from step S111 to step S113 and step S117.

  In step S114 in which a threshold value for determining whether or not the resonator 20 is operating normally is calculated, the engine control device 40 uses the map or mathematical expression stored in advance in the storage medium to The abnormality determination level of the amplitude and phase of the pulsation corresponding to the driving state is calculated. Specifically, the engine control device 40 acquires a pulsation waveform in which the crank angle detected by the crank position sensor 33 corresponds to the pressure fluctuation in the intake pipe 12 during normal operation of the resonator 20. Using this pulsation waveform as a reference, a value obtained by adding a predetermined value or a predetermined coefficient to the amplitude of the pulsation waveform of the pulsation is set as an amplitude abnormality determination level. In addition, a predetermined phase difference is set as a phase abnormality determination level. Note that these abnormality determination levels may be variables that increase or decrease in accordance with the operating state of the engine 10.

  In step S115, the waveform of the actual pulsation occurring in the intake pipe 12 is detected. This waveform is acquired by associating the crank angle detected by the crank position sensor 33 with the pressure in the intake pipe 12 detected by the air flow meter 50. The amplitude of this actual pulsation waveform is detected and acquired as the intake pulsation level for the amplitude. In addition, an actual pulsation phase is detected, and a difference from the reference pulsation phase acquired in step S114 is obtained. Then, the phase difference between the reference pulsation waveform and the actual pulsation waveform is acquired as the intake pulsation level for the phase. In step S116, the determination is made based on the amplitude and phase intake pulsation levels acquired in step S115 and the amplitude and phase abnormality determination levels calculated in step S114. If the intake pulsation level is greater than the abnormality determination level for either one of the amplitude and the phase, the diagnosis flow proceeds to step S117. On the other hand, in step S116, when any intake pulsation level is equal to or lower than the abnormality determination level, the diagnosis flow ends.

  In the third embodiment described above, since it is determined whether or not the resonator 20 is operating normally using both the amplitude and phase of the actual pulsation, the accuracy of the determination can be improved. Therefore, the intake control device can surely diagnose that the resonator 20 is abnormal.

(Fourth embodiment)
The fourth embodiment of the present invention is still another modification of the first embodiment, and the resonance frequency of the resonator 20 is feedback-controlled as in the first embodiment. In the fourth embodiment, the engine control device 40 determines whether or not the resonator 20 is operating normally based on the frequency of pulsation generated in the intake pipe 12. Hereinafter, the diagnosis flow of the fourth embodiment will be described. In addition, the process similar to 1st embodiment is implemented from step S111 to step S113 and step S117.

  In step S114 for calculating an abnormality determination level that is a threshold value for determining whether or not the resonator 20 is operating normally, the engine control device 40 uses a map or a mathematical expression stored in advance in a storage medium. Thus, the abnormality determination level of the pulsation frequency corresponding to the operating state of the engine 10 is calculated. As the frequency abnormality determination level, the pulsation generated in the intake pipe 12 when the resonator 20 operates normally is set as a reference pulsation, and an upper limit value and a lower limit value of a frequency band including the reference pulsation frequency are set. Specifically, a value obtained by adding and subtracting a predetermined value to the reference pulsation frequency, or a value obtained by multiplying one or more predetermined coefficients and a predetermined coefficient less than 1 is set. These abnormality determination levels may be variables that vary according to the operating state of the engine 10.

  In step S115, the frequency of the pulsation is detected from the pulsation output in the intake pipe 12 measured by the air flow meter 50, and is acquired as the intake pulsation level for the frequency. In the process corresponding to step S116, determination is performed based on the intake pulsation level detected in step S115 and the abnormality determination level calculated in step S114. In this process, when the intake pulsation level is larger than the upper limit value of the abnormality determination level or smaller than the lower limit side of the abnormality determination level, that is, outside the predetermined frequency band including the frequency of the reference pulsation, The diagnosis flow moves to step S117. On the other hand, in step S116, when the intake pulsation level is between the lower limit value and the upper limit value of the abnormality determination level, the diagnosis flow ends.

  As in the fourth embodiment described above, it is possible to determine whether or not the resonator 20 is operating normally by using the actual pulsation frequency. Therefore, the intake control device can diagnose that the resonator 20 is abnormal.

(Other embodiments)
Although a plurality of embodiments of the present invention have been described above, the present invention is not construed as being limited to these embodiments, and can be applied to various embodiments without departing from the spirit thereof. .

  In the above embodiment, the engine control device 40 determines whether or not the resonator 20 is in the steady state by recording the transition of the target resonance frequency of the resonator 20, and the resonator 20 is only in the steady state. It was determined whether or not it was in a normal operating state. However, the intake control device may be configured to determine whether or not the resonator 20 is in a normal operating state without performing the determination of the steady state. Further, the determination of whether or not the resonator 20 is in a steady state may record and use the transition of the operating state of the engine 10 instead of the transition of the target resonance frequency. This is because the target resonance frequency is calculated based on the operating state of the engine 10, and therefore, when the engine 10 is operating in a steady state, it can be estimated that the resonator 20 is in a steady state.

  In the above embodiment, the pulsation generated in the intake pipe 12 is detected using the air flow meter 50. However, other than the air flow meter 50, for example, a pressure sensor or the like may be used as long as the pulsation in the intake pipe 12 can be detected. By installing a pressure sensor electrically connected to the engine control device 40 in the intake pipe 12 in the vicinity of the resonator 20, the pulsation in the intake pipe 12 can be detected as a pressure fluctuation.

  In the first and second embodiments, whether or not the resonator 20 is in a normal operating state is determined from the amplitude of pulsation in the intake pipe 12. In the third embodiment, whether or not the resonator 20 is in a normal operating state is determined from the amplitude and phase of the pulsation in the intake pipe 12 and from the frequency of the pulsation in the intake pipe 12 in the fourth embodiment. It was. As described above, the determination of the operating state of the resonator 20 may use any of the amplitude, frequency or wavelength, and frequency of pulsation, or may be used in combination as appropriate.

  In addition to the resonator 20 that adjusts the resonance frequency by changing the volume of the resonance chamber 21a, the present invention is applied to an intake control device that includes various pulsation damping devices that can adjust the resonance frequency. An abnormality of the pulsation damping device can be diagnosed.

DESCRIPTION OF SYMBOLS 10 Engine (internal combustion engine), 11 Combustion chamber, 12 Intake pipe, 12a Air cleaner, 12b Surge tank, 14 Throttle body, 14a Throttle valve, 15 Throttle motor, 16 Crankshaft, 18 Variable valve timing mechanism, 19 Intake valve, 20 Resonator (Pulsation damping device), 21 Container body, 21a Resonance chamber, 23 Connection pipe, 25 Movable lid, 27 Actuator, 27a Rotating shaft, 28 Actuator support, 31 Throttle position sensor (operating state detection means), 33 Crank position sensor (Operating state detecting means), 36 water temperature sensor, 37 knock sensor, 38 exhaust gas sensor, 40 engine control device (control means, operating state determining means, steady state determining means), 50 air flow meter (pulsation detecting means), 10 0 Intake control device

Claims (9)

Pulsation detecting means for detecting pulsation of air sucked into the combustion chamber in an intake pipe communicating with the combustion chamber of the internal combustion engine;
An operating state detecting means for detecting an operating state of the internal combustion engine;
A pulsation damping device that is connected to the intake pipe and attenuates pulsation in the intake pipe by resonance, and the frequency of resonance can be adjusted;
Control means for controlling the resonant frequency of the pulsation damping device based on the output of the operating state detection means;
Under the condition that the pulsation damping device is controlled by the control means, based on the pulsation in the intake pipe by the output of the pulsation detection means and the reference pulsation set according to the output of the operating state detection means And an operation state determination means for determining whether or not the pulsation damping device is operating normally. An intake control device for an internal combustion engine, comprising: The operating state determining means includes
Obtaining the amplitude of pulsation in the intake pipe from the output of the pulsation detecting means;
When the pulsation amplitude is larger than a threshold amplitude set based on the reference pulsation amplitude, it is determined that the pulsation damping device is not in a normally operating state. The intake control device for an internal combustion engine according to claim 1. The operating state determining means includes
Obtaining the frequency of pulsation in the intake pipe from the output of the pulsation detecting means;
The pulsation damping device is determined not to be in a normally operating state when the pulsation frequency is outside a predetermined frequency band including the reference pulsation frequency. Or an intake air control apparatus for an internal combustion engine according to 2; The operating state determining means includes
Obtaining the phase of the pulsation in the intake pipe from the output of the pulsation detecting means;
When the phase difference between the phase of the pulsation and the phase of the pulsation serving as the reference is larger than a predetermined phase difference, it is determined that the pulsation damping device is not in a normally operating state. The intake control device for an internal combustion engine according to any one of claims 1 to 3. A steady state determination means for determining whether or not the pulsation damping device is in a steady state;
5. The operation state determination unit determines whether or not the pulsation damping device is operating normally based on the determination that the operation state determination unit is in a steady state. An intake control device for an internal combustion engine according to claim 1. The control means controls the pulsation attenuator so that a frequency at which the pulsation attenuator resonates becomes a target resonance frequency calculated based on an output of the operating state detector.
The steady state determination means determines that the pulsation damping device is in a steady state when a change in the target resonance frequency within a predetermined time transitions within a predetermined range. 6. An intake control device for an internal combustion engine according to 5.   The control means performs feedback control of the pulsation attenuator so that a frequency at which the pulsation attenuator resonates approximates a target resonance frequency calculated based on the output of the operating state detector. The intake control device for an internal combustion engine according to any one of claims 1 to 6.   The control means feeds back the pulsation attenuator so that a difference between a value related to the pulsation waveform corresponding to the target resonance frequency and a value related to the pulsation waveform of the intake pipe based on the output of the pulsation detection means decreases. 8. The intake control apparatus for an internal combustion engine according to claim 7, wherein the control is performed.   The pulsation detecting means includes an air flow meter for measuring a flow rate of air flowing in the intake pipe, and detects a waveform of pulsation in the intake pipe based on an output measured by the air flow meter. Item 9. The intake control device for an internal combustion engine according to any one of Items 1 to 8.

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