JP2018028278A - Control device and control method of internal combustion engine - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a control device and a control method of internal combustion engine capable of suppressing noise generating by a pressure wave toward an intake passage side from a combustion chamber.SOLUTION: A control device 50 of an internal combustion engine A includes an intake passage 20 and an exhaust passage 30 communicating with a combustion chamber 11, an intake valve 13 and an exhaust valve 14, and a variable valve drive mechanism 14a which makes opening/closing timing variable is used as a drive mechanism of the exhaust valve 14. The control device of an internal combustion engine includes: an exhaust valve control part 52 for adjusting a phase of the opening/closing timing of the exhaust valve 14 with respect to a rotational motion of a crank shaft 15 of the internal combustion engine by controlling the variable valve drive mechanism 14a; and a noise insulation valve control part 53 for controlling the opening of the noise insulation valve 24 disposed in the intake passage 20. The noise insulation valve control part 53 controls the noise insulation valve 24 in the direction in which the opening becomes small, when the exhaust valve control part 52 is advancing the opening/closing timing of the exhaust valve 14 on an expansion stroke side.SELECTED DRAWING: Figure 3

Description

  The present invention relates to a control device and a control method for an internal combustion engine.

  In recent years, with the tightening of exhaust gas regulations, there is a demand for reducing exhaust emissions even during cold operation where the coolant temperature and lubricating oil temperature of the engine are low.

  In Patent Document 1, in order to meet such a demand, the opening / closing timing of the exhaust valve is advanced during cold operation (meaning that the phase of the opening / closing timing of the exhaust valve with respect to the rotational movement of the crankshaft is advanced to the expansion stroke side). (Hereinafter the same shall apply) to disclose a technique for reducing NOx, early activation of the catalyst of the exhaust emission control device, shortening the warm-up time, and the like.

JP-A-2015-132195

  However, when the opening / closing timing of the exhaust valve is advanced as in Patent Document 1, there is a problem that abnormal noise is generated outside the engine.

  FIG. 1 is a diagram for explaining such a problem.

  In the drawing, the dotted line L1 is the lift curve of the exhaust valve before being advanced, the thick dotted line L2 is the lift curve of the exhaust valve after being advanced, the dashed line L3 is the lift curve of the intake valve, and the solid line L4 is the opening and closing of the exhaust valve The behavior of the pressure in the combustion chamber when the timing is advanced is shown.

  As shown in FIG. 1, when the opening / closing timing of the exhaust valve is advanced, the amount of overlap between the intake valve and the exhaust valve being opened simultaneously is small, and the intake valve and the exhaust valve are simultaneously closed. The compressed state of the combustion gas or the like is generated in the combustion chamber at the timing. Since the pressure in the combustion chamber in such a state is higher than when the opening / closing timing of the exhaust valve is not advanced, when the intake valve is opened, residual gas in the combustion chamber is caused by the pressure in the combustion chamber. It will blow back to the intake side. As a result, a pressure wave from the combustion chamber toward the intake passage is generated, and this pressure wave reaches the vicinity of the intake port through which the engine sucks air from the outside, so that abnormal noise is generated outside the engine.

  Such abnormal noise leads to discomfort for the driver of the vehicle. In particular, in the case of a diesel engine, since the compression ratio of the combustion chamber is made higher than that of a gasoline engine, such a pressure wave increases and abnormal noise generated outside the engine tends to increase.

  The present invention has been made in view of the above problems, and an object of the present invention is to provide a control device and a control method for an internal combustion engine that can suppress abnormal noise generated by a pressure wave from the combustion chamber toward the intake passage. And

  The main present invention that solves the above-described problems includes an intake passage and an exhaust passage that communicate with a combustion chamber, an intake valve that opens and closes between the combustion chamber and the intake passage, and a space between the combustion chamber and the exhaust passage. An internal combustion engine control device using a variable valve drive mechanism having a variable opening / closing timing as a drive mechanism of the exhaust valve, and controlling the variable valve drive mechanism. An exhaust valve control unit that adjusts the phase of the opening and closing timing of the exhaust valve with respect to the rotational movement of the crankshaft of the internal combustion engine; and a sound insulation valve control unit that controls the opening degree of the sound insulation valve disposed in the intake passage; The sound insulation valve control unit opens the sound insulation valve when the exhaust valve control unit advances the opening / closing timing of the exhaust valve to the expansion stroke side. The control apparatus for an internal combustion engine for controlling the direction is reduced.

  In addition, there are an intake passage and an exhaust passage communicating with the combustion chamber, an intake valve that opens and closes between the combustion chamber and the intake passage, and an exhaust valve that opens and closes between the combustion chamber and the exhaust passage. An internal combustion engine control method using a variable valve drive mechanism with variable opening / closing timing as the exhaust valve drive mechanism, wherein the variable valve drive mechanism is controlled to rotate a crankshaft of the internal combustion engine. When adjusting the phase of the opening / closing timing of the exhaust valve with respect to movement and the opening / closing timing of the exhaust valve is advanced to the expansion stroke side, the opening of the sound insulation valve disposed in the intake passage is reduced. And a control method for controlling the direction of the internal combustion engine.

  According to the present invention, when the opening / closing timing of the exhaust valve is advanced, the pressure wave from the combustion chamber toward the intake passage can be shielded by the throttle valve, and as a result, the noise generated by the pressure wave can be prevented. It becomes possible to suppress.

A diagram for explaining abnormal noise generated outside the engine The figure which shows an example of the whole structure of the diesel engine which concerns on 1st Embodiment. The figure which shows an example of the control flow of the exhaust valve and throttle valve which concern on 1st Embodiment The figure which shows an example of the control map for setting the advance amount of the exhaust valve which concerns on 2nd Embodiment, and the opening degree of a throttle valve The figure which shows the position of the phase corresponding to the advance amount of the exhaust valve of the control map which concerns on 2nd Embodiment. The figure which shows an example of the control flow of the exhaust valve and throttle valve which concern on 2nd Embodiment

(First embodiment)
Hereinafter, the configuration of the internal combustion engine and the control device thereof according to the first embodiment will be described with reference to FIGS. 2 and 3. In the present embodiment, a self-ignition internal combustion engine (hereinafter also referred to as a diesel engine) will be described as an example of the internal combustion engine.

  FIG. 2 is a diagram illustrating an example of the overall configuration of the diesel engine according to the present embodiment.

  The diesel engine (internal combustion engine) A according to this embodiment includes an engine body 10 (combustion chamber 11, fuel injection device 12, intake valve 13, exhaust valve 14, intake valve drive mechanism 13a, exhaust valve drive mechanism 14a, crankshaft 15). ), Intake passage 20, exhaust passage 30, air cleaner 21, turbocharger 22, intercooler 23, intake throttle valve 24 (corresponding to the “sound insulation valve” of the present invention), external EGR (Exhaust Gas Recirculation) device 31, exhaust purification device 32, various sensors 41 to 46, and an ECU (Electronic Control Unit) 50.

  The intake passage 20 is a flow path that draws fresh air (air) from the upstream intake port 20 a and introduces the fresh air into the combustion chamber 11. In the intake passage 20, an air cleaner 21, a compressor of a turbocharger 22, an intercooler 23, and an intake throttle valve 24 are provided in this order from the upstream intake port 20 a to the combustion chamber 11.

  The exhaust passage 30 is a flow path for discharging the exhaust gas after combustion discharged from the combustion chamber 11 to the outside of the engine A. In the exhaust passage 30, an external EGR device 31, a turbine of the turbocharger 22, and an exhaust purification device 32 are provided in this order from the combustion chamber 11 to an exhaust port (not shown).

  The air cleaner 21 receives air sucked from the air inlet 20a, removes impurities from the air, and sends the air to the turbocharger 22 side.

  The turbocharger 22 includes a compressor provided on the intake passage 20 side, a turbine provided on the exhaust passage 30 side, and a shaft member that connects the turbine and the compressor. The turbocharger 22 rotates the turbine using the pressure of the exhaust gas in the exhaust passage 30. The turbocharger 22 operates a coaxial compressor by the rotational motion of the turbine, compresses the air flowing in from the air cleaner 21, and sends it out to the intercooler 23 side of the intake passage 20.

  The intercooler 23 cools the compressed air sent out from the turbocharger 22 and distributes it to the combustion chamber 11 side.

  The intake throttle valve 24 adjusts the amount of air flowing through the intake passage 20 by controlling the opening of the valve. The intake throttle valve 24 adjusts the opening of the intake passage 20 by controlling the opening of the valve, and shields the pressure wave from the combustion chamber 11 toward the intake passage 20 (details will be described later). ). The intake throttle valve 24 is, for example, an electronically controlled butterfly valve, and controls the opening degree of the butterfly valve by driving a DC motor connected to the butterfly valve in accordance with a control signal sc from the ECU 50. . The intake throttle valve 24 can continuously control the opening degree between the fully open state and the fully closed state.

  Here, the intake throttle valve 24 is disposed downstream of the intercooler 23 in the intake passage 20 and upstream of the connection portion between the intake passage 20 and the EGR pipe 31a. That is, the intake throttle valve 24 suppresses the pressure wave from the combustion chamber 11 toward the intake passage 20 toward the upstream side of the intercooler 23.

  The external EGR device 31 circulates part of the exhaust gas flowing through the exhaust passage 30 to the intake passage 20. The external EGR device 31 includes an EGR passage 31a, an EGR cooler 31b, and an EGR valve 31c. Here, the EGR passage 31 a communicates the exhaust passage 30 and the intake passage 20, and distributes exhaust gas exhausted from the combustion chamber 11 to the exhaust passage 30 to the intake passage 20 side. The EGR cooler 31b cools the EGR gas flowing through the EGR passage 31a. The EGR valve 31c adjusts the flow rate of EGR gas flowing through the EGR passage 31a.

  The exhaust purification device 32 is an impurity removal / filter provided in the exhaust passage 30 and includes an oxidation catalyst, a diesel particulate filter (DPF), a selective reduction catalyst (SCR), and the like.

  The engine body 10 includes a combustion chamber 11, a fuel injection device 12, an intake valve 13, an intake valve drive mechanism 13a, an exhaust valve 14, an exhaust valve drive mechanism 14a, and a crankshaft 15. Although a detailed description is omitted here, the diesel engine A according to this embodiment is a four-cylinder engine, and the intake passage 20 is connected to the four combustion chambers 11 via an intake manifold (not shown). The exhaust passage 30 is branched and joined from the four combustion chambers 11 via an exhaust manifold (not shown).

  The combustion chamber 11 is formed on the upper surface of the piston in the cylinder. In the combustion chamber 11, the air intake stroke, the air compression stroke, the combustion gas expansion stroke, and the combustion gas exhaust stroke are repeatedly performed. The piston reciprocates, and the crankshaft 15 connected to the piston rotates.

  The fuel injection device 12 injects fuel into the combustion chamber 11 in the vicinity of the compression top dead center of the piston in which the inside of the combustion chamber 11 becomes high temperature and pressure. The fuel injection device 12 is installed in the upper part of the combustion chamber 11 so that the tip of the fuel injection nozzle is disposed in the combustion chamber 11. The fuel injection device 12 controls the electromagnetic solenoid to inject fuel from the fuel injection nozzle into the combustion chamber 11.

  The intake valve 13 is provided in an intake port of the intake passage 20 and introduces air into the combustion chamber 11 from the intake passage 20 by opening and closing the intake passage 20. The intake valve 13 is driven by an intake valve drive mechanism 13a provided above the cylinder, and performs an operation of opening and closing the intake passage 20.

  The intake valve drive mechanism 13a is, for example, a cam mechanism that is interlocked with the rotational movement of the crankshaft 15. As the crankshaft 15 rotates, the intake valve drive mechanism 13a transmits the rotational power to a camshaft (not shown) via a timing belt (not shown), and a cam attached to the camshaft. Is configured to reciprocate so as to open and close the intake passage 20 by periodically pushing down the intake valve 13.

  The exhaust valve 14 is provided at an exhaust port of the exhaust passage 30 and discharges exhaust gas from the combustion chamber 11 to the exhaust passage 30 by opening and closing the exhaust passage 30. The exhaust valve 14 is driven by an exhaust valve drive mechanism 14a provided above the cylinder, and performs an operation of opening and closing the exhaust passage 30.

  The exhaust valve drive mechanism 14a has a cam mechanism similar to the intake valve drive mechanism 13a, and is a variable valve drive mechanism that can arbitrarily control the opening / closing timing of the exhaust valve 14 by a control signal from the ECU 50.

  As the exhaust valve drive mechanism 14a, for example, a vane variable valve drive mechanism can be used. The vane variable valve drive mechanism changes the rotational phase of the camshaft relative to the rotational motion of the crankshaft 15 to advance the opening / closing timing of the exhaust valve 14 toward the expansion stroke or return it to the intake stroke. The vane variable valve drive mechanism includes a rotor connected to a camshaft, a housing that houses the rotor and interlocks with the crankshaft 15, an advance chamber and a retard angle formed between the housing and the rotor. An oil control valve that controls oil pressure in the chamber is included. The oil control valve controls the oil hydraulic pressure in the advance chamber and the retard chamber to shift the rotational phase of the rotor relative to the housing back and forth. With this configuration, the exhaust valve drive mechanism 14a continuously changes the opening / closing timing of the exhaust valve 14 to the advance side or the retard side.

  The variable valve driving mechanism for driving the exhaust valve 14 is not limited to the vane type, and a cam switching type, an electric motor type, a camless type, or the like may be used. Further, the variable valve drive mechanism may adjust the lift amount of the exhaust valve 14 in addition to the phase of the opening / closing timing of the exhaust valve 14. In order to make the opening / closing timing of the intake valve 13 variable, a variable valve drive mechanism may also be used for the intake valve drive mechanism 13a.

  The various sensors 41 to 46 are provided for detecting the state of each part of the engine A and the like. Specifically, each part of the engine A is provided with an engine rotation sensor 41, an accelerator opening sensor 42, a throttle valve position sensor 43, a cam position sensor 44, a cooling water temperature sensor 45, an exhaust temperature sensor 46, and the like. The detected values detected by these various sensors 41 to 46 are transmitted to the ECU 50.

  Here, the engine rotation sensor 41 is a sensor that detects the rotation speed of the crankshaft 15. The accelerator opening sensor 42 is a sensor that detects the accelerator opening. The throttle valve position sensor 43 is a sensor that detects the opening degree of the intake throttle valve 24. The cam position sensor 44 is a sensor that detects the rotational phase of the camshaft of the exhaust valve drive mechanism 14a. The cooling water temperature sensor 45 is a sensor that detects the temperature of the cooling water flowing in the cooling water circulation path (not shown). The exhaust temperature sensor 46 is a sensor that detects the temperature of the exhaust gas flowing into the exhaust purification device 32 from the exhaust passage 30. Any of these sensors can be realized by a known sensor.

  In addition to the above sensor, a sensor for detecting the catalyst temperature of the exhaust purification device 32 or a sensor for detecting the pressure in the combustion chamber 11 may be provided.

  The ECU 50 (corresponding to a control device) controls each part of the engine A, and includes, for example, a CPU (Central Processing Unit), a ROM (Read Only Memory), a RAM (Random Access Memory), an input port, an output port, and the like. It is configured to include.

  Here, for example, when the engine A is in a cold operation, the ECU 50 advances the opening / closing timing of the exhaust valve 14 and controls the intake throttle valve 24 in a direction in which the opening is reduced for sound insulation ( This will be described later with reference to FIG. The ECU 50 includes an operation state determination unit 51, an exhaust valve control unit 52, and a throttle valve control unit 53 as a configuration for realizing such a function. These functions are realized, for example, by the CPU executing a computer program.

  The operation state determination unit 51 determines whether or not the engine A is in a cold operation state based on the detection values of the cooling water temperature sensor 45 and the exhaust temperature sensor 46. The cold operation means an operation in a state where the cooling water temperature or the lubricating oil temperature of the engine A is low, such as when the engine A is started.

  The exhaust valve control unit 52 controls the exhaust valve drive mechanism 14 a to adjust the phase of the opening / closing timing of the exhaust valve 14 with respect to the rotational movement of the crankshaft 15. When the operation state determination unit 51 determines that the cold operation is being performed, the exhaust valve control unit 52 outputs a control signal sa to the exhaust valve drive mechanism 14a to advance the opening / closing timing of the exhaust valve 14 to the expansion stroke side. Horn.

  The throttle valve control unit 53 (corresponding to the “sound insulation valve control unit” of the present invention) controls the intake throttle valve 24 disposed in the intake passage 20 to adjust the opening degree. When the exhaust valve control unit 52 advances the opening / closing timing of the exhaust valve 14, the throttle valve control unit 53 outputs a control signal sc to the intake throttle valve 24 to control the opening degree to be decreased. . By doing so, the region where the pressure wave from the combustion chamber 11 toward the intake passage 20 side passes through the intake throttle valve 24 is narrowed, and the pressure wave is shielded. Note that “controlling in such a direction that the opening degree decreases” means that the opening degree of the intake throttle valve 24 is controlled to be smaller than the current opening degree. In other words, the throttle valve control unit 53 is not limited to a mode in which the opening degree of the intake throttle valve 24 is switched between the fully open state and the fully closed state, but naturally includes a mode in which the throttle valve control unit 53 is controlled from the fully open state to the semi-closed state. Further, the throttle valve control unit 53 may further finely adjust the opening degree of the intake throttle valve 24 according to the accelerator opening degree or the like.

  In addition to the above, the ECU 50 determines the fuel injection start timing and the fuel injection amount of the fuel injection device 12 based on the accelerator opening, and the fuel injection is performed so that the determined fuel injection start timing and fuel injection amount are obtained. A control signal sb is output to the device 12. Further, the ECU 50 outputs a control signal sd to the EGR valve 31c in order to control the opening degree of the EGR valve 31c.

  Next, an example of the control flow of the exhaust valve 14 and the intake throttle valve 24 will be described.

  FIG. 3 is a diagram illustrating an example of a control flow of the exhaust valve 14 and the intake throttle valve 24 during the cold operation. 3 is executed by the ECU 50 according to the computer program as described above.

  Here, the operation state determination unit 51 determines whether or not the engine A is in the cold operation every predetermined time (for example, every second) based on the detection values of the cooling water temperature sensor 45 and the exhaust temperature sensor 46. Suppose you are. And when the driving | running state determination part 51 determines with the engine A being in cold operation, when the process of step S1, S2 shown in FIG. 3 is performed, and it determines with the said cold operation having been complete | finished The processes of steps S3 and S4 are executed. Note that the operating state determination unit 51 determines, for example, when the cooling water temperature detected by the cooling water temperature sensor 45 is lower than a predetermined warm-up completion temperature or when the exhaust temperature detected by the exhaust temperature sensor 46 is a predetermined catalyst activation temperature. The engine A is determined to be in a cold operation when the temperature is lower than, for example, when the cooling water temperature reaches the warm-up completion temperature and the catalyst temperature reaches a predetermined catalyst activation temperature, the cold operation is performed. Shall be terminated.

  During the cold operation, the exhaust valve control unit 52 controls the exhaust valve drive mechanism 14a so that the opening / closing timing of the exhaust valve 14 is advanced to the expansion stroke side, as shown in FIG. More specifically, the exhaust valve control unit 52 advances the opening / closing timing of the exhaust valve 14 toward the expansion stroke side, thereby opening the exhaust valve 14 at an early stage with respect to the compression top dead center, and causing high-temperature combustion gas to flow. While exhausting into the exhaust passage 30, the exhaust valve 14 is closed early with respect to the compression top dead center, and the combustion gas remains in the combustion chamber 11.

  Thus, the residual gas remaining in the combustion chamber 11 raises the compression start temperature in the combustion chamber 11 to stabilize the combustion of the fuel in the combustion chamber 11 and from the cold operation to the normal operation. Switching time can be shortened. In addition, the catalyst temperature of the exhaust gas purification device 32 can be raised at an early stage by the high-temperature combustion gas discharged into the exhaust passage 30.

  However, as described above, when the opening / closing timing of the exhaust valve 14 is advanced, when the intake valve 13 is opened, the residual gas compressed in the combustion chamber 11 is blown out to the intake passage 20 side. When a pressure wave from the combustion chamber 11 toward the intake passage 20 is generated and reaches the intake port 20a, abnormal noise is generated outside the engine A. Therefore, the ECU 50 according to the present embodiment controls the intake throttle valve 24 in a direction in which the opening degree is decreased so as to be interlocked with the advance angle control of the opening / closing timing of the exhaust valve 14.

  Returning to FIG. 3, the control flow will be described.

  First, the ECU 50 (throttle valve control unit 53) controls the intake throttle valve 24 in a direction in which the opening becomes smaller (step S1). After that, the ECU 50 (exhaust valve controller 52) controls the exhaust valve drive mechanism 14a so that the opening / closing timing of the exhaust valve 14 is advanced by a predetermined angle toward the expansion stroke (step S2). Note that this control is executed by feedback control with reference to detection values of the throttle valve position sensor 43 and the cam position sensor 44, for example.

  After step S2, the ECU 50 (operating state determination unit 51) continuously monitors the detected values of the cooling water temperature sensor 45 and the exhaust temperature sensor 46 in such a state, and terminates the cold operation in the same manner as described above. Determine. If the ECU 50 (operation state determination unit 51) determines to end the cold operation and switch to the normal operation, the ECU 50 (operation state determination unit 51) performs the subsequent process of step S3.

  When switching to normal operation, first, the ECU 50 (exhaust valve control unit 52) controls the exhaust valve drive mechanism 14a so as to return the opening / closing timing of the exhaust valve 14 to the intake stroke side (step S3). Next, the ECU 50 (throttle valve control unit 53) controls the intake throttle valve 24 in a direction in which the opening degree increases (step S4).

  In a diesel engine, in order to reduce the pumping loss due to the intake throttle valve 24, the traveling speed of the vehicle is generally controlled by the amount of fuel injected into the combustion chamber 11. Therefore, in the present embodiment, for example, the intake throttle valve 24 is closed from the fully open state to the half-open state in the process of step S1, is opened to the fully open state in the process of step S4, and is then held in that state. Shall be.

  As described above, the ECU 50 controls the intake throttle valve 24 in a direction in which the opening degree is reduced before the opening / closing timing of the exhaust valve 14 is advanced, and advances the opening / closing timing of the exhaust valve 14. The intake throttle valve 24 is controlled so as to increase the opening at the timing after the state is returned to the intake stroke side. By doing so, the pressure wave from the combustion chamber 11 toward the intake passage 20 can be reliably suppressed by the intake throttle valve 24.

  As described above, according to the ECU 50 according to the present embodiment, when the opening / closing timing of the exhaust valve 14 is advanced, the intake throttle valve 24 is controlled so as to decrease the opening degree. Therefore, the control device 50 can shield the pressure wave from the combustion chamber 11 toward the intake passage 20 by the intake throttle valve 24. As a result, it is possible to suppress noise generated by the pressure wave. .

(Second Embodiment)
Next, an internal combustion engine control apparatus (ECU 50) according to a second embodiment will be described with reference to FIGS.

  The ECU 50 according to this embodiment changes the advance amount of the exhaust valve 14 stepwise during cold operation, and changes the opening of the intake throttle valve 24 according to the advance amount of the exhaust valve 14. This is different from the first embodiment. Note that description of configurations common to the first embodiment is omitted.

FIG. 4 is a view showing a control map for setting the advance amount θ of the exhaust valve 14 and the opening degree μ of the intake throttle valve 24. FIG. 5 shows the position of the phase corresponding to the advance amounts θ _{1 to} θ ₄ of the exhaust valve 14 in the control map.

  It is assumed that a control map as shown in FIG. 4 is stored in advance in the ECU 50 according to the present embodiment. The control map shown in FIG. 4 is data in which the target value of the advance amount θ of the exhaust valve 14 and the target value of the opening μ of the intake throttle valve 24 are set in advance with respect to the actually measured values of the engine speed and the engine load. The ECU 50 (the exhaust valve control unit 52 and the throttle valve control unit 53) controls the advance angle θ of the exhaust valve 14 and the opening degree μ of the intake throttle valve 24 according to the control map. Here, the actual measured value of the engine load is obtained based on the accelerator opening.

In the control map, the target value of the advance amount θ is set to be smaller as the measured values of the engine speed and the engine load are higher (θ ₄ > θ ₁ ). In other words, in the cold operation immediately after the start of the engine A, the advance amount θ is large (fourth region in FIG. 4), and the advance amount θ decreases stepwise as the engine speed increases. (The third region, the second region, and the first region in FIG. 4). As a result, during the cold operation immediately after the start of the engine A, the compression start temperature of the combustion chamber 11 is significantly increased. On the other hand, in consideration of the fact that the output torque decreases when the advance amount θ of the exhaust valve 14 is increased, the advance amount is increased as the engine speed and the engine load increase with time in the control map. The target value of θ is set so as to decrease stepwise.

Further, in the control map, target values for the openings μ _{1 to} μ ₄ of the intake throttle valve 24 corresponding to the target values of the advance amounts θ _{1 to} θ ₄ of the exhaust valve 14 are set (μ ₁ > μ). ₄ ). Specifically, the control map is set such that the opening degree μ of the intake throttle valve 24 decreases as the advance amount θ of the exhaust valve 14 increases. That is, as the advance amount θ of the exhaust valve 14 increases, the pressure in the combustion chamber 11 increases, and the pressure wave from the combustion chamber 11 toward the intake passage 20 increases. On the other hand, if the opening degree μ of the intake throttle valve 24 is decreased, the pumping loss caused by the intake throttle valve 24 also increases. In the control map, in consideration of such a viewpoint, the opening degree μ of the intake throttle valve 24 is set to increase stepwise as the advance amount θ of the exhaust valve 14 decreases stepwise.

  Thus, the control map takes into account the torque characteristics and the pumping loss caused by the intake throttle valve 24, reduces NOx during cold operation, early activation of the catalyst of the exhaust purification device 32, shortens the warm-up time, etc. It is set to be able to plan.

  FIG. 6 is a diagram illustrating an example of a control flow of the exhaust valve 14 and the intake throttle valve 24 using the control map. Here, in the same way as in the first embodiment, when the exhaust valve 14 is advanced to the expansion stroke side in order to reliably suppress the pressure wave from the combustion chamber 11 toward the intake passage 20, the intake throttle first In the case where the valve 24 is controlled in a direction in which the opening is decreased and the exhaust valve 14 is returned to the intake stroke side, the intake throttle valve 24 is controlled in a direction in which the opening is increased after the exhaust valve 14 is returned first. It has become.

  The control flow shown in FIG. 6 is executed every predetermined time (for example, every 0.5 seconds) when the operation state determination unit 51 determines that it is in the cold operation state.

  In the control flow shown in FIG. 6, first, the ECU 50 (exhaust valve control unit 52) calculates a target value for the advance amount of the exhaust valve 14 according to the control map (step S11). Then, the ECU 50 (exhaust valve control unit 52) determines whether or not the target value of the advance amount of the exhaust valve 14 matches the measured value of the advance amount of the exhaust valve 14 detected from the cam position sensor 44. If it matches (step S12: YES), the process ends. If not (step S12: NO), the exhaust valve 14 and the intake throttle valve 24 are controlled. To do.

  When the target value of the advance amount of the exhaust valve 14 is larger than the actually measured value (step S13: YES), first, the ECU 50 (throttle valve control unit 53) controls the intake throttle valve 24 in a direction in which the opening is decreased. Then, the ECU 50 (exhaust valve controller 52) advances the exhaust valve 14 (step S15).

  On the other hand, when the target value of the advance amount of the exhaust valve 14 is smaller than the actually measured value (step S13: NO), first, the ECU 50 (exhaust valve control unit 52) sets the opening / closing timing of the exhaust valve 14 to the intake stroke side. Then, the ECU 50 (throttle valve control unit 53) controls the intake throttle valve 24 in a direction in which the opening is reduced (step S17).

  The ECU 50 repeats such processing so that the exhaust valve drive mechanism 14a and the target value of the advance amount of the exhaust valve 14 and the target value of the opening degree of the intake throttle valve 24 set in the control map are obtained. The intake throttle valve 24 is controlled.

Specifically, immediately after starting the engine A, immediately after starting the engine A, the control map corresponds to the fourth region (step S12: NO, step S13: YES). Therefore, ECU 50 (throttle valve control unit 53), first, in order to suppress the pressure wave at the time of advance, and controls the opening degree of the intake throttle valve 24 to the minimum value mu ₄ (step S14). Thereafter, ECU 50 (the exhaust valve control unit 52) controls the exhaust valve drive mechanism 14a so that the advance of the exhaust valve 14 to the maximum value theta ₄ (step S15).

When the engine speed gradually increases immediately after starting and reaches the third region of the control map (step S12: NO, step S13: NO), the ECU 50 (exhaust valve control unit 52) causes the exhaust valve 14 to advance. controlling the exhaust valve drive mechanism 14a such that the angular amount to a smaller theta ₃ than theta ₄ (step S16). Thereafter, ECU 50 (throttle valve control unit 53) performs control so that the opening degree of the intake throttle valve 24 becomes large mu ₃ than mu ₄ (step S17).

  Subsequently, according to the shift to the second region and the first region of the control map, the ECU 50 first decreases the advance amount of the exhaust valve 14 (step S16), and then the intake throttle valve 24. The process of enlarging the opening degree (step S17) is executed.

  Then, similarly to the first embodiment, when the operation state determination unit 51 determines to end the cold operation, the operation proceeds to the normal operation with the advance amount of zero.

  As described above, according to the control device 50 according to the present embodiment, the advance amount of the exhaust valve 14 is decreased stepwise and the opening of the intake throttle valve 24 is increased stepwise. It has become. Therefore, while considering the pumping loss and torque characteristics of the intake throttle valve 24, it is possible to reduce NOx, activate the catalyst of the exhaust purification device early, shorten the warm-up time, and the like.

  In the above embodiment, the ECU 50 (throttle valve control unit 53) is configured to determine the opening degree μ of the intake throttle valve 24 based on the advance amount of the exhaust valve 14, the actual measured value of the engine speed, and the like. ing. However, the ECU 50 (throttle valve control unit 53) measures the pressure in the combustion chamber 11 in order to directly obtain the magnitude of the pressure wave from the combustion chamber 11 toward the intake passage 20, and the pressure in the combustion chamber 11 is measured. Of course, the opening degree μ of the intake throttle valve 24 may be determined on the basis of the actually measured value.

(Other embodiments)
In the above-described embodiment, an aspect in which the intake throttle valve 24 is used as an example of a configuration for shielding a pressure wave from the combustion chamber 11 toward the intake passage 20 is shown. However, in addition to the intake throttle valve 24, a separate sound insulating valve may be provided. Further, since the sound insulating valve only needs to be able to shield pressure waves from the combustion chamber 11 toward the intake passage 20, it may be located at each intake port of the intake manifold or upstream of the intercooler 23 in the intake passage 20. It is good also as a position. However, it is desirable to use the existing intake throttle valve 24 in the internal combustion engine A from the viewpoint of reducing the number of parts and reducing the cost.

  Moreover, in the said embodiment, the aspect which performs a process at the time of a cold operation was shown as an example of a structure of the exhaust valve control part 52 and the throttle valve control part 53 of ECU50. However, it goes without saying that the exhaust valve control unit 52 may advance the opening / closing timing of the exhaust valve 14 other than during the cold operation. For example, the exhaust valve control unit 52 may advance the opening / closing timing of the exhaust valve 14 even when the engine brake is applied in order to reduce the torque. Then, the throttle valve control unit 53 may control the intake throttle valve 24 in a direction in which the opening degree decreases in accordance with this. However, when the throttle valve control unit 53 controls the intake throttle valve 24 in a direction in which the opening becomes smaller in cases other than cold operation, the air amount necessary for combustion in the combustion chamber 11 is sufficiently secured. It is desirable to control the intake throttle valve 24 so that the opening degree is larger than in the case of cold operation.

  In the above embodiment, as an example of the configuration of the operation state determination unit 51 of the ECU 50, whether or not it is in the cold operation state is sequentially determined based on the detection values of the cooling water temperature sensor 45 and the exhaust temperature sensor 46, and the like. The mode of determination was shown. However, the mode of the operation state determination unit 51 is arbitrary, and for example, a configuration in which a predetermined time period after the engine A is started is determined as a cold operation state.

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

  At least the following matters will become apparent from the description of this specification and the accompanying drawings.

  An intake passage 20 and an exhaust passage 30 communicating with the combustion chamber 11, an intake valve 13 that opens and closes between the combustion chamber 11 and the intake passage 20, and an opening and closing between the combustion chamber 11 and the exhaust passage 30. And a control device 50 for an internal combustion engine A using a variable valve drive mechanism 14a having a variable opening / closing timing as a drive mechanism of the exhaust valve 14, and comprising the variable valve drive mechanism 14a. The exhaust valve control unit 52 for adjusting the opening / closing timing phase of the exhaust valve 14 with respect to the rotational movement of the crankshaft 15 of the internal combustion engine, and the opening degree of the sound insulation valve 24 disposed in the intake passage 20 are controlled. A sound insulation valve control unit 53 for controlling the sound insulation valve control unit 53, wherein the exhaust valve control unit 52 expands the opening / closing timing of the exhaust valve 14. When you are allowed to advance to the travel side, it discloses a control device 50 for an internal combustion engine A which controls the sound insulation valve 24 in the direction of opening is reduced. According to the control device 50 of the internal combustion engine A, when the opening / closing timing of the exhaust valve 14 is advanced, the pressure wave from the combustion chamber 11 toward the intake passage 20 can be suppressed by the sound insulation valve 24. As a result, it is possible to suppress abnormal noise caused by the pressure wave.

  Further, the sound insulation valve control unit 53 in the control device 50 of the internal combustion engine A opens the sound insulation valve 24 before the exhaust valve control unit 52 advances the opening / closing timing of the exhaust valve 14 to the expansion stroke side. And the exhaust valve controller 52 controls the sound insulation valve 24 in a direction in which the opening increases before the opening / closing timing of the exhaust valve 14 is returned to the intake stroke side. May be. According to the control device 50 of the internal combustion engine A, it is possible to reliably suppress the pressure wave from the combustion chamber 11 toward the intake passage 20 side.

  The sound insulation valve control unit 53 in the control device 50 of the internal combustion engine A determines the opening of the sound insulation valve 24 based on the pressure of the combustion chamber 11 at the compression top dead center between the exhaust stroke and the intake stroke. In addition, the sound insulation valve 24 may be controlled so as to achieve the opening degree. According to the control device 50 of the internal combustion engine A, it is possible to control the opening of the sound insulation valve 24 according to the magnitude of the pressure wave described above while considering the pumping loss due to the sound insulation valve 24.

  Further, the sound insulation valve control unit 53 in the control device 50 of the internal combustion engine A determines the opening degree of the sound insulation valve 24 based on the advance amount of the opening / closing timing of the exhaust valve 14 so as to be the opening degree. Alternatively, the sound insulation valve 24 may be controlled. According to the control device 50 of the internal combustion engine A, it is possible to control the opening of the sound insulation valve 24 according to the magnitude of the pressure wave described above while considering the pumping loss due to the sound insulation valve 24.

  The internal combustion engine A may be a self-ignition internal combustion engine. In a self-ignition type internal combustion engine, the compression wave in the combustion chamber is made higher than that in an ignition type internal combustion engine, so that the above-described pressure wave increases and abnormal noise generated outside the engine A tends to increase. Therefore, the control device 50 for the internal combustion engine can be more suitably used particularly for the control device 50 for the self-ignition internal combustion engine.

  Further, in the control device 50 of the internal combustion engine A, when the internal combustion engine is in a cold operation state, the exhaust valve control unit 52 advances the opening / closing timing of the exhaust valve 14 to the expansion stroke side. The variable valve drive mechanism 14a may be controlled, and the sound insulation valve control unit 53 may control the sound insulation valve 24 in a direction in which the opening is reduced. According to the control device 50 of the internal combustion engine A, while suppressing the pressure wave generated by the advance angle by the sound insulation valve 24, the NOx is reduced during the cold operation, the catalyst of the exhaust purification device 32 is activated early, The machine time can be shortened.

  In the control device 50 of the internal combustion engine A, when the internal combustion engine is in a cold operation state, the exhaust valve control unit 52 advances the opening / closing timing of the exhaust valve 14 to the expansion stroke side, The variable valve drive mechanism 14a is controlled so that the amount of advance is reduced stepwise, and the sound insulation valve control unit 53 controls the sound insulation valve 24 in a direction in which the opening becomes smaller, and then the opening degree. The sound insulation valve 24 may be controlled so as to increase stepwise. According to the control device 50 of the internal combustion engine A, NOx reduction during cold operation, early activation of the catalyst of the exhaust purification device 32, warm-up time, taking into account the pumping loss and torque characteristics generated by the sound insulation valve 24 Can be shortened.

  Further, an intake passage 20 and an exhaust passage 30 that communicate with the combustion chamber 11, an intake valve 13 that opens and closes between the combustion chamber 11 and the intake passage 20, and a space between the combustion chamber 11 and the exhaust passage 30 are provided. An internal combustion engine control method using a variable valve drive mechanism 14a having a variable opening / closing timing as a drive mechanism of the exhaust valve 14, wherein the variable valve drive mechanism 14a is When the control is performed to adjust the phase of the opening / closing timing of the exhaust valve 14 relative to the rotational movement of the crankshaft 15 of the internal combustion engine, and when the opening / closing timing of the exhaust valve 14 is advanced to the expansion stroke side, A control method for an internal combustion engine is disclosed that includes a process of controlling the sound insulation valve 24 disposed in the intake passage 20 in a direction in which the opening is reduced.

  The control device for an internal combustion engine according to the present disclosure can be suitably used to suppress noise generated by a pressure wave from the combustion chamber toward the intake passage.

A Internal combustion engine 10 Engine body 11 Combustion chamber 12 Fuel injection device 13 Intake valve 14 Exhaust valve 15 Crankshaft 20 Intake passage 21 Air cleaner 22 Turbocharger 23 Intercooler 24 Intake throttle valve 30 Exhaust passage 31 External EGR device 32 Exhaust purification device 41 Engine Rotation sensor 42 Accelerator opening sensor 43 Throttle valve position sensor 44 Cam position sensor 45 Cooling water temperature sensor 46 Exhaust temperature sensor 50 ECU
51 Operation State Determination Unit 52 Exhaust Valve Control Unit 53 Throttle Valve Control Unit

Claims (8)

An intake passage and an exhaust passage that communicate with the combustion chamber, an intake valve that opens and closes between the combustion chamber and the intake passage, and an exhaust valve that opens and closes between the combustion chamber and the exhaust passage, A control device for an internal combustion engine using a variable valve drive mechanism that varies opening and closing timing as the exhaust valve drive mechanism,
An exhaust valve controller that controls the variable valve drive mechanism to adjust the phase of the opening / closing timing of the exhaust valve with respect to the rotational movement of the crankshaft of the internal combustion engine;
A sound insulation valve controller that controls the opening of the sound insulation valve disposed in the intake passage,
The control device for an internal combustion engine, wherein the sound insulation valve control unit controls the sound insulation valve in a direction in which the opening is reduced when the exhaust valve control unit advances the opening / closing timing of the exhaust valve to the expansion stroke side. The sound insulation valve controller
Before the exhaust valve control unit advances the opening / closing timing of the exhaust valve to the expansion stroke side, the sound insulation valve is controlled in a direction in which the opening is reduced,
2. The internal combustion engine according to claim 1, wherein, before the exhaust valve control unit returns the opening / closing timing of the exhaust valve to the intake stroke side, the sound insulation valve is controlled in a direction in which the opening degree increases. Control device. The sound insulation valve controller
The opening of the sound insulation valve is determined based on the pressure of the combustion chamber at the compression top dead center between the exhaust stroke and the intake stroke, and the sound insulation valve is controlled so as to be the opening. The control apparatus for an internal combustion engine according to claim 1 or 2. The sound insulation valve controller
The opening of the sound insulation valve is determined based on the advance amount of the opening / closing timing of the exhaust valve, and the sound insulation valve is controlled to be the opening. The control apparatus for an internal combustion engine according to the item. The control device for an internal combustion engine according to any one of claims 1 to 4, wherein the internal combustion engine is a self-ignition internal combustion engine. When the internal combustion engine is in a cold operation state,
The exhaust valve control unit controls the variable valve drive mechanism so that the opening / closing timing of the exhaust valve is advanced to the expansion stroke side,
The control device for an internal combustion engine according to any one of claims 1 to 5, wherein the sound insulation valve control unit controls the sound insulation valve in a direction in which an opening degree decreases. When the internal combustion engine is in a cold operation state,
The exhaust valve control unit controls the variable valve drive mechanism so that the amount of advance is reduced stepwise after the exhaust valve opening / closing timing is advanced to the expansion stroke side,
The said sound insulation valve control part controls the said sound insulation valve so that the said opening may become large in steps, after controlling the said sound insulation valve in the direction where an opening becomes small. Control device for internal combustion engine. An intake passage and an exhaust passage that communicate with the combustion chamber, an intake valve that opens and closes between the combustion chamber and the intake passage, and an exhaust valve that opens and closes between the combustion chamber and the exhaust passage, A control method for an internal combustion engine in which a variable valve drive mechanism that makes opening / closing timing variable is used as the exhaust valve drive mechanism,
A process of controlling the variable valve drive mechanism to adjust the phase of the opening / closing timing of the exhaust valve with respect to the rotational movement of the crankshaft of the internal combustion engine;
When the opening / closing timing of the exhaust valve is advanced to the expansion stroke side, a process of controlling the sound insulation valve disposed in the intake passage in a direction in which the opening is reduced;
An internal combustion engine control method comprising:

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