JP2014206094A - Control apparatus for internal combustion engine - Google Patents

Abstract

PROBLEM TO BE SOLVED: To improve startability of an internal combustion engine.SOLUTION: A control apparatus for an internal combustion engine includes an electric motor for starting the internal combustion engine, and a lash adjuster for adjusting a valve clearance by supplying lubricating oil for the internal combustion engine. The control apparatus for the internal combustion engine comprises a calculation part for calculating torque of the electric motor, which is required for start-up of the internal combustion engine, on the basis of the sinking amount of the lash adjuster, when the internal combustion engine is in a stopped state.

Description

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

  A lash adjuster that adjusts a valve clearance using hydraulic pressure in an internal combustion engine is known. Here, when the internal combustion engine stops while the intake valve is lifted, the lash adjuster sinks due to the force received from the cam while the engine is stopped. Thereby, the opening / closing timing of the intake valve at the next engine start changes, so that the intake air amount changes. If it does so, there exists a possibility that the combustion at the time of start-up of an internal combustion engine may become unstable.

  On the other hand, there is a technique for setting the valve lift characteristics of the intake valves so that all cylinders are in a zero lift state in which the valve lift amounts of the intake valves of all the cylinders to which the lash adjuster is applied are almost zero when the engine is stopped. It is known (for example, refer to Patent Document 1).

  By the way, in some hybrid vehicles including an electric motor in addition to the internal combustion engine as a driving source of the vehicle, the internal combustion engine is started by the electric motor. In such a case, if the internal combustion engine is started with the minimum necessary torque, the fuel efficiency can be improved. However, if the amount of air in the cylinder changes due to the sinking of the hydraulic lash adjuster, the torque required to start the internal combustion engine changes, which may make it difficult to start the internal combustion engine in some cases.

JP 2003-056316 A International Publication No. 2011-117972 JP 2000-248968 A JP 2008-095544 A

  The present invention has been made in view of the above-described problems, and an object thereof is to improve the startability of an internal combustion engine.

In order to solve the above problems, in the present invention,
In a control device for an internal combustion engine, comprising: an electric motor that starts the internal combustion engine; and a lash adjuster that adjusts a valve clearance by supplying lubricating oil of the internal combustion engine.
When the internal combustion engine is stopped, a calculation unit is provided for calculating the torque of the electric motor required for starting the internal combustion engine based on the sinking amount of the lash adjuster.

When the internal combustion engine is stopped, the lubricating oil gradually escapes from the lash adjuster, and the lash adjuster gradually sinks. Then, the valve timing changes. Due to this influence, the amount of air in the cylinder changes. When the air amount in the cylinder changes as the lash adjuster sinks, the torque required to start the internal combustion engine changes. Here, if the torque of the electric motor is insufficient, the internal combustion engine cannot be started. On the other hand, if the torque of the electric motor is excessive, fuel consumption may be deteriorated. Therefore, it is desirable to set the torque of the electric motor when starting the internal combustion engine to the minimum necessary torque. here,
The torque required for starting the internal combustion engine is a torque required for cranking the internal combustion engine, and changes according to the valve timing. Since the valve timing is related to the amount of sinking of the lash adjuster, the torque required for starting the internal combustion engine can be calculated based on the amount of sinking of the lash adjuster. Thereby, the startability of the internal combustion engine can be further improved. The sink amount of the lash adjuster may be an amount of change from the protruding amount (which may be the total length) of the lash adjuster when sufficient hydraulic pressure is applied to the lash adjuster. Further, the sink amount of the lash adjuster may be a change amount from the protruding amount (which may be the total length) of the lash adjuster when the internal combustion engine is operating.

  In the present invention, the calculation unit can calculate an air amount in a cylinder of the internal combustion engine based on a sink amount of the lash adjuster.

  As described above, the valve timing changes as the lash adjuster sinks. Due to this influence, the amount of air in the cylinder changes. Here, the amount of lash adjuster sink is related to the amount of change in valve timing, and if the amount of lash adjuster sink is known, the amount of change in valve timing can be determined. If the amount of change in valve timing is known, the amount of air present in the cylinder when the engine is started can also be calculated. If the fuel supply amount is calculated in accordance with the air amount so as to achieve the target air-fuel ratio, for example, the optimum fuel supply amount can be calculated. Thereby, the startability of an internal combustion engine can be improved.

  Therefore, in the present invention, the calculation unit calculates a change amount of the valve timing of the intake valve based on a sink amount of the lash adjuster and, based on the change amount of the valve timing, in the cylinder of the internal combustion engine The amount of air may be calculated.

  In the present invention, the calculation unit can calculate the fuel supply amount into the cylinder based on the air amount in the cylinder of the internal combustion engine.

  Here, as the amount of air in the cylinder changes, the optimum fuel supply amount also changes. Therefore, by adjusting the fuel supply amount in accordance with the air amount in the cylinder, it is possible to adjust to an appropriate air-fuel ratio, so that the startability of the internal combustion engine can be improved.

  In the present invention, the calculation unit can calculate a sinking amount of the lash adjuster based on a stop position of the piston.

  The amount of lash adjuster sinking depends on how much force the lash adjuster receives from the cam. That is, the amount of lash adjuster sinking varies depending on the cam position. Since the position of the cam is correlated with the stop position of the piston, the amount of sinking of the lash adjuster can be obtained from the stop position of the piston.

  In the present invention, the calculation unit can further calculate a sink amount of the lash adjuster based on a hydraulic pressure of the internal combustion engine and a stop time of the internal combustion engine.

  Here, the sink amount of the lash adjuster is also affected by the hydraulic pressure of the internal combustion engine and the stop time of the internal combustion engine. By taking these effects into consideration, the calculation accuracy of the lash adjuster sinking amount can be improved.

  Further, in the present invention, the calculation unit calculates a change amount of the valve timing of the intake valve based on a sink amount of the lash adjuster, and is necessary for starting the internal combustion engine based on the change amount of the valve timing. The torque of the electric motor can be calculated.

  In other words, since the valve timing of the intake valve changes according to the amount of lash adjuster sink, the amount of change in valve timing can be calculated based on the amount of lash adjuster sink. Further, since the torque required for starting the internal combustion engine changes according to the change amount of the valve timing, the torque of the electric motor required for starting the internal combustion engine can be calculated based on the change amount of the valve timing. .

  According to the present invention, the startability of the internal combustion engine can be improved.

It is a figure for demonstrating the system configuration | structure of an Example. It is a figure for demonstrating the influence of the sink of a lash adjuster at the time of ignition start. It is the figure which showed the relationship between the stop position of a piston, and the amount of sinking of a lash adjuster. It is the figure which showed the relationship between the amount of sinks of a lash adjuster, and the variation | change_quantity of valve timing. It is the figure which showed the relationship between the variation | change_quantity of valve timing, and the torque required for engine starting. 3 is a flowchart showing a control flow at the start of the internal combustion engine according to the first embodiment. It is the figure which showed the relationship between oil_pressure | hydraulic and the amount of sinking of a lash adjuster. It is the figure which showed the relationship between the stop period of an internal combustion engine, and the amount of sinking of a lash adjuster. 6 is a flowchart illustrating a control flow at the time of starting an internal combustion engine according to a second embodiment. It is a time chart which showed transition of the output of the electric motor before starting of an internal-combustion engine. It is the figure which showed the relationship between the torque required for rotation of an internal combustion engine, and the amount of sinking of a lash adjuster. 7 is a flowchart illustrating a control flow at the time of starting an internal combustion engine according to a third embodiment. It is a time chart which showed transition of the output of the electric motor before starting of an internal-combustion engine. 7 is a flowchart showing a control flow at the time of starting an internal combustion engine according to a fourth embodiment. It is the flowchart which showed the control flow at the time of starting of the internal combustion engine which concerns on an Example.

  DESCRIPTION OF EMBODIMENTS Hereinafter, embodiments for carrying out the present invention will be exemplarily described in detail with reference to the drawings. However, the dimensions, materials, shapes, relative arrangements, and the like of the components described in this embodiment are not intended to limit the scope of the present invention only to those unless otherwise specified.

<Example 1>
FIG. 1 is a diagram for explaining the system configuration of the present embodiment. In this example, an internal combustion engine 1 is provided. The internal combustion engine 1 is a V-type 8-cylinder gasoline engine. FIG. 1 shows only one cylinder among the plurality of cylinders 2. Further, the internal combustion engine 1 according to the present embodiment is mounted on a hybrid vehicle provided with an electric motor 100 in addition to the internal combustion engine 1 as a vehicle drive source. The internal combustion engine 1 may be a diesel engine. The engine type may be other than the V type 8 cylinder. The electric motor 100 cranks the internal combustion engine 1 when the internal combustion engine 1 is started.

  The internal combustion engine 1 includes a cylinder block 4 having a piston 3 therein. The piston 3 is connected to the crankshaft 6 via a connecting rod 5. A crank angle sensor 61 is provided in the vicinity of the crankshaft 6. The crank angle sensor 61 is configured to detect the rotation angle (that is, the crank angle) of the crankshaft 6.

  A cylinder head 7 is assembled to the upper part of the cylinder block 4. The cylinder head 7 includes an intake port 9 that communicates with the cylinder 2. An intake pipe 10 is connected to the cylinder head 7. The intake pipe 10 is provided with a throttle 12. The intake port 9 communicates the intake pipe 10 and the cylinder 2. An intake valve 11 is provided at the end of the intake port 9 and the cylinder 2 side. In this embodiment, a plurality of intake valves 11 are provided corresponding to the plurality of intake ports 9 provided for each cylinder 2. In FIG. 1, one intake port 9 and one intake valve 11 are shown.

  The cylinder head 7 is provided with an intake camshaft 36 for driving the intake valve 11. The intake camshaft 36 rotates by transmission of rotational force from the crankshaft 6 of the internal combustion engine 1 (transmission of rotational force by a timing belt or the like). The intake camshaft 36 is provided with an intake cam 36a. Then, when the intake cam 36a rotates integrally with the intake cam shaft 36, the intake valve 11 is opened and closed. The intake valve 11 is urged by a valve spring 92 in a direction in which the intake valve 11 is closed.

  A rocker arm 81 is provided between the intake cam 36 a and the intake valve 11. The rocker arm 81 is provided such that a roller 81 a provided at the center of the rocker arm 81 is in contact with the intake cam 36 a, one end of the rocker arm 81 is in contact with the end of the intake valve 11, and the other end is in contact with the lash adjuster 91. The lash adjuster 91 includes a body 91a fixed to the cylinder head 7 and a plunger 91b that advances and retreats from the body 91a. During operation of the internal combustion engine 1, the plunger 91 b moves in the axial direction by the pressure of the lubricating oil supplied into the lash adjuster 91, and pushes the other end of the rocker arm 81. Thereby, the valve clearance is adjusted.

  The cylinder head 7 includes an exhaust port 13 that communicates with the cylinder 2. An exhaust valve 14 is provided at a connection portion between the exhaust port 13 and the cylinder 2. The internal combustion engine 1 is provided with a hydraulic pressure sensor 64 that detects the hydraulic pressure.

  In addition, the system of this embodiment includes an ECU 60 as an electronic control device. A throttle 12 and the like are connected to the output side of the ECU 60. In addition to the crank angle sensor 61, an accelerator opening sensor 63 that outputs an electrical signal corresponding to the amount by which the driver has depressed the accelerator pedal 62 is connected to the input side of the ECU 60. The ECU 60 executes overall control of the internal combustion engine 1 such as fuel injection control and ignition timing control based on the output of each sensor. Further, the ECU 60 selects and switches either the electric motor 100 or the internal combustion engine 1 as a drive source of the hybrid vehicle according to the traveling state of the hybrid vehicle.

Here, when the internal combustion engine 1 is stopped, the lubricating oil is not supplied to the lash adjuster 91. When the internal combustion engine 1 is stopped, the hydraulic pressure inside the lash adjuster 91 gradually decreases. For this reason, the plunger 91b moves toward the inside of the body 91a, and the lash adjuster 91 sinks. At this time, the sinking amount of the lash adjuster 91 varies depending on the force pushed by the intake cam 36a. When the internal combustion engine 1 is started, even if the internal combustion engine 1 is cranked by the electric motor 100, the hydraulic pressure does not increase immediately. Therefore, the internal combustion engine 1 is started with the lash adjuster 91 depressed. For this reason, when the internal combustion engine 1 is started, the valve timing deviates from a target value (which may be a set value). Then, an error occurs in the estimated value of the in-cylinder air amount. Furthermore, there is a possibility that misfire may occur or harmful substances in the exhaust gas increase. In addition, since the torque required to start the internal combustion engine 1 changes, it may be difficult to start the internal combustion engine 1 by the electric motor 100.

  If a starter motor is provided and sufficient cranking time is provided by the starter motor, the fuel can be supplied to the internal combustion engine 1 and ignited after the sinking of the lash adjuster 91 is eliminated. However, for example, in an engine in which ignition is started by injecting fuel into a cylinder in the expansion stroke when the engine is stopped and then igniting sequentially from a cylinder that has exceeded the top dead center, the engine is stopped in the intake stroke when the engine is stopped. An in-cylinder air amount estimation error occurs due to a change in valve timing caused by the sink of the lash adjuster 91 in the cylinder. Thereby, there is a possibility that an appropriate air-fuel ratio cannot be obtained.

  In the hybrid vehicle, the internal combustion engine 1 may be cranked using the electric motor 100 instead of the starter motor. In order to improve fuel efficiency, the internal combustion engine 1 may be started with the torque of the electric motor 100 suppressed to a necessary minimum. However, when the valve timing changes, the torque required for cranking changes. In a hybrid vehicle, the electric motor 100 may be switched to the internal combustion engine 1 when the vehicle is traveling. However, if the torque changes at this time, there is a possibility that the traveling of the vehicle may be affected or the internal combustion engine 1 may be difficult to start. is there.

  Here, FIG. 2 is a diagram for explaining the influence of the sinking of the lash adjuster 91 at the time of starting ignition. In FIG. 2, an arrow indicates a period during which the intake valve 11 is open, and a rotation direction of the arrow indicates a direction in which the crank angle increases. When the sink amount of the lash adjuster is 0 (when the lash adjuster does not sink), when there is a sink, the closing timing (IVC) of the intake valve 11 is advanced. Then, when the closing timing of the intake valve 11 changes, the in-cylinder air amount changes.

  Further, for example, in the V-type 8-cylinder engine, the explosion order is 1st cylinder (# 1), 8th cylinder (# 8), 7th cylinder (# 7), 3rd cylinder (# 3), 6th cylinder. (# 6) No. 5 cylinder (# 5), No. 4 cylinder (# 4), No. 2 cylinder (# 2). For example, in # 1 and # 8, even if there is almost no estimation error of the in-cylinder air amount, an estimation error of the in-cylinder air amount occurs in # 7, # 3, and # 6 due to the sink of the lash adjuster 91.

  Therefore, in this embodiment, the amount of sinking of the lash adjuster 91 when the internal combustion engine 1 is started is obtained. Then, the change amount of the valve timing is obtained from the sink amount of the lash adjuster 91.

Here, FIG. 3 is a diagram showing the relationship between the stop position of the piston 3 and the amount of sinking of the lash adjuster 91. When the internal combustion engine 1 is stopped, the rocker arm 81 is pushed by the intake cam 36a, and therefore the rocker arm 81 pushes the lash adjuster 91. And since the force with which the rocker arm 81 pushes the lash adjuster 91 changes according to the position of the intake cam 36a, the sinking amount of the lash adjuster 91 changes. Further, since the position of the intake cam 36a is determined by the stop position of the piston 3, the amount of lash adjuster sinking is determined according to the stop position of the piston 3. For this reason, if the relationship of FIG. 3 is obtained in advance by experiment or simulation and stored in the ECU 60, the amount of sink of the lash adjuster 91 can be obtained based on the stop position of the piston 3. The stop position of the piston 3 can be detected by the crank angle sensor 61.

  FIG. 4 is a graph showing the relationship between the amount of lash adjuster 91 sinking and the amount of change in valve timing. Since the change amount of the valve timing changes according to the sink amount of the lash adjuster 91, if this relationship is obtained in advance by experiments or simulations and stored in the ECU 60, the valve timing is determined based on the sink amount of the lash adjuster 91. The amount of change can be calculated. Note that the change amount of the valve timing may be directly obtained from the stop position of the piston 3. This relationship is obtained in advance by experiments or simulations and stored in the ECU 60.

  Then, the actual valve timing is calculated from the set valve timing (the valve timing when sufficient lubricating oil is supplied to the lash adjuster 91) and the amount of change in the valve timing. The in-cylinder air amount is estimated based on the actual valve timing obtained in this way, and the fuel injection amount is determined according to the in-cylinder air amount. It should be noted that the relationship between the actual valve timing and the in-cylinder air amount is obtained in advance through experiments or simulations and stored in the ECU 60. Further, the in-cylinder air amount may be estimated from the change amount of the valve timing. The relationship between the change amount of the valve timing and the in-cylinder air amount is obtained in advance through experiments or simulations and stored in the ECU 60.

  Further, based on the obtained valve timing, a torque required for starting the engine is calculated, and the output of the electric motor 100 is determined based on the torque.

  Here, FIG. 5 is a diagram showing the relationship between the amount of change in valve timing and the torque required for engine start. This relationship is obtained in advance by experiments or simulations and stored in the ECU 60. The relationship shown in FIG. 5 is that of a V-type 8-cylinder engine. The greater the amount of change in valve timing, the greater the torque required to start the engine. This tendency varies depending on the engine type. . Further, the torque required for starting the engine may be directly obtained from the sink amount of the lash adjuster 91 or the piston stop position. This relationship is obtained in advance by experiments or simulations and stored in the ECU 60.

  FIG. 6 is a flowchart showing a control flow when the internal combustion engine 1 according to this embodiment is started. This routine is executed by the ECU 60 when the internal combustion engine 1 is started. It is also executed for each cylinder. In this embodiment, the ECU 60 that executes the routine shown in FIG. 6 corresponds to the calculation unit in the present invention.

  In step S101, the stop position of the piston 3 is detected. The stop position of the piston 3 is detected by a crank angle sensor 61.

  In step S102, the amount of sinking of the lash adjuster 91 is calculated. In this step, the sink amount of the lash adjuster 91 is obtained from the stop position of the piston 3 in accordance with the relationship of FIG.

  In step S103, the amount of change in valve timing is calculated. In this step, the change amount of the valve timing is obtained from the sink amount of the lash adjuster 91 according to the relationship of FIG. The change amount of the valve timing may be a correction amount of the valve timing. In this step, the actual valve timing may be obtained.

In step S104, the in-cylinder air amount is calculated. The in-cylinder air amount is calculated based on the amount of change in valve timing. Note that the in-cylinder air amount may be obtained directly from the sink amount of the lash adjuster 91 or the piston stop position. This relationship is obtained in advance by experiments or simulations and stored in the ECU 60.

  In step S105, the fuel supply amount is calculated. In this step, the fuel supply amount is corrected based on the in-cylinder air amount so that the target air-fuel ratio at the time of engine start is obtained. The fuel is directly injected into the cylinder 2.

  In step S106, the torque of the electric motor 100 necessary for starting the engine is calculated. In this step, the torque of the electric motor 100 is calculated from the amount of change in valve timing in accordance with the relationship of FIG.

  In step S107, the output of the electric motor 100 at the time of engine start is changed based on the torque calculated in step S106.

  As described above, according to this embodiment, it is possible to correct the estimation error of the in-cylinder air amount and the error of the fuel injection amount due to the sinking of the lash adjuster 91. Further, even when the torque required for starting the internal combustion engine 1 changes due to the change of the valve timing, the output of the electric motor 100 can be corrected. Thereby, the startability of the internal combustion engine 1 can be improved. Further, the amount of harmful substances generated when the internal combustion engine 1 is started can be reduced.

<Example 2>
In this embodiment, the amount of in-cylinder air is estimated more accurately by determining the amount of sinking of the lash adjuster 91 with higher accuracy. Since other devices are the same as those in the first embodiment, the description thereof is omitted.

  In the first embodiment, the sinking amount of the lash adjuster 91 is calculated based on the stop position of the piston 3. On the other hand, in the present embodiment, the sink amount of the lash adjuster 91 is further calculated in consideration of the hydraulic pressure of the internal combustion engine 1 and the stop period of the internal combustion engine 1.

  Here, FIG. 7 is a diagram showing the relationship between the hydraulic pressure and the amount of sinking of the lash adjuster 91. If the hydraulic pressure is equal to or higher than the predetermined pressure, the sink amount of the lash adjuster 91 is 0. However, if the hydraulic pressure is lower than the predetermined pressure, the lower the hydraulic pressure, the larger the sink amount of the lash adjuster 91 is.

  FIG. 8 is a diagram showing the relationship between the stop period of the internal combustion engine 1 and the amount of sinking of the lash adjuster 91. The longer the stop time, the greater the amount of lash adjuster 91 sinking. The relationship shown in FIGS. 7 and 8 is obtained in advance through experiments or simulations and stored in the ECU 60.

  Thus, by calculating the sink amount of the lash adjuster 91 in consideration of the hydraulic pressure and the stop period of the internal combustion engine 1, the sink amount of the lash adjuster 91 can be calculated with higher accuracy.

  FIG. 9 is a flowchart showing a control flow when the internal combustion engine 1 according to this embodiment is started. This routine is executed by the ECU 60 when the internal combustion engine 1 is started. It is also executed for each cylinder. In addition, about the step where the same process as the said flow is made, the same code | symbol is attached | subjected and description is abbreviate | omitted. In the present embodiment, the ECU 60 that executes the routine shown in FIG. 9 corresponds to the calculation unit in the present invention.

  In this routine, when the process of step S101 is completed, the process proceeds to step S201. In step S201, the hydraulic pressure and the stop period of the internal combustion engine 1 are detected. The hydraulic pressure of the internal combustion engine 1 is obtained by a hydraulic pressure sensor 64. The stop period is obtained by a timer built in the ECU 60.

  In step S202, the sinking amount of the lash adjuster 91 is calculated. In this step, the amount of sinking of the lash adjuster 91 is obtained according to the relationship of FIGS. For example, the amount of sinking of the lash adjuster 91 is obtained according to the relationship of FIG. 3, and the amount of sinking of the lash adjuster 91 is corrected according to the relationship of FIGS. Note that a coefficient for correcting the sinking amount of the lash adjuster 91 may be obtained based on the relationship shown in FIGS.

  As described above, according to the present embodiment, since the calculation accuracy of the sink amount of the lash adjuster 91 is increased, the in-cylinder air amount and the torque required for starting the engine can be obtained with higher accuracy. Thereby, the discharge amount of harmful substances can be reduced. Moreover, generation | occurrence | production of misfire can be suppressed. Furthermore, the startability of the internal combustion engine 1 can be improved.

<Example 3>
In the above embodiment, the stop position of the piston 3 is detected by the crank angle sensor 61. However, since some of the crank angle sensors 61 have a low resolution, it may be difficult to accurately detect the stop position of the piston 3. In contrast, in this embodiment, the stop position of the piston 3 is detected using the electric motor 100. Since other devices are the same as those in the first embodiment, the description thereof is omitted.

  In this embodiment, before starting the internal combustion engine 1, the output of the electric motor 100 is gradually increased, and the stop position of the piston 3 is based on the torque of the electric motor 100 when the internal combustion engine 1 starts to rotate. Is detected.

  Here, FIG. 10 is a time chart showing the transition of the output of the electric motor 100 before the internal combustion engine 1 is started. The output of the electric motor 100 is gradually increased, and the torque when the rotation of the internal combustion engine 1 is detected is detected. Since the torque when the rotation of the internal combustion engine 1 is detected is related to the stop position of the piston 3, the stop position of the piston 3 can be obtained based on this torque. These relationships are obtained in advance by experiments or simulations and stored in the ECU 60.

  FIG. 11 is a diagram showing the relationship between the torque necessary for the rotation of the internal combustion engine 1 (the torque of the electric motor 100 when the rotation of the internal combustion engine 1 is detected) and the amount of sinking of the lash adjuster 91. . Instead of the amount of sinking of the lash adjuster 91, the amount of change in valve timing or the amount of change in the closing timing (IVC) of the intake valve 11 may be used. This relationship is obtained in advance by experiments or simulations and stored in the ECU 60. According to FIG. 11, as the required torque increases, the sink amount of the lash adjuster 91 decreases, but this tendency varies depending on the engine type.

  FIG. 12 is a flowchart showing a control flow when the internal combustion engine 1 according to this embodiment is started. This routine is executed by the ECU 60 when the internal combustion engine 1 is started. It is also executed for each cylinder. In addition, about the step where the same process as the said flow is made, the same code | symbol is attached | subjected and description is abbreviate | omitted.

  In step S301, the electric motor 100 is energized. The electric power supplied at this time is set to such a small value that the internal combustion engine 1 does not rotate.

  In step S302, it is determined whether rotation of the internal combustion engine 1 has been detected. In this step, it is determined by the crank angle sensor 61 whether or not the internal combustion engine 1 is rotating. If an affirmative determination is made in step S302, the process proceeds to step S304, whereas if a negative determination is made, the process proceeds to step S303.

  In step S303, the output of the electric motor 100 is increased by a predetermined value. This predetermined value is set to gradually increase the output of the electric motor 100 in order to obtain the torque at which the rotation of the internal combustion engine 1 starts. For this reason, when the predetermined value is large, the torque at which the internal combustion engine 1 starts rotating earlier can be obtained, but the accuracy thereof is lowered. Therefore, the predetermined value is determined based on the balance between the time required for obtaining the torque at which the rotation of the internal combustion engine 1 starts and the accuracy. And after step S303 is processed, it returns to step S302. That is, step S303 is repeatedly executed until the rotation of the internal combustion engine 1 is detected, and the output of the electric motor 100 increases by a predetermined value.

  In step S304, a torque required for starting the internal combustion engine 1 is calculated. This torque is calculated based on the output of the electric motor 100 when the rotation of the internal combustion engine 1 is detected. Further, the output of the electric motor 100 is obtained from the electric power supplied to the electric motor 100.

  In step S305, the sinking amount of the lash adjuster 91 is calculated. In this step, the amount of sinking of the lash adjuster 91 is calculated according to the relationship of FIG. Then, the process proceeds to step S103.

  As described above, according to this embodiment, the amount of sinking of the lash adjuster 91 can be obtained with high accuracy without using the crank angle sensor 61, so that the in-cylinder air amount and the torque required for engine start can be further increased. It can be obtained with high accuracy. Thereby, the discharge amount of harmful substances can be reduced. Moreover, generation | occurrence | production of misfire can be suppressed. Furthermore, the startability of the internal combustion engine 1 can be improved.

<Example 4>
In the third embodiment, since the output of the electric motor 100 is gradually increased, it may take time until the rotation of the internal combustion engine 1 is detected. In contrast, in this embodiment, the time required until the rotation of the internal combustion engine 1 is detected is shortened by learning the torque necessary for starting the internal combustion engine 1. Since other devices are the same as those in the first embodiment, the description thereof is omitted.

  Here, FIG. 13 is a time chart showing the transition of the output of the electric motor 100 before the internal combustion engine 1 is started. A solid line indicates a transition according to the present embodiment, and a broken line indicates a transition according to the third embodiment. In the third embodiment, the output of the electric motor 100 gradually increases from 0, but in this embodiment, the output is increased to some extent from the beginning.

  For example, the lowest torque measured 100 times is set as the initial torque of the electric motor 100.

  FIG. 14 is a flowchart showing a control flow when starting the internal combustion engine 1 according to this embodiment. This routine is executed by the ECU 60 when the internal combustion engine 1 is started. It is also executed for each cylinder. In addition, about the step where the same process as the said flow is made, the same code | symbol is attached | subjected and description is abbreviate | omitted.

  In step S401, the initial torque of the electric motor 100 is determined. For example, the lowest torque measured in the past 100 times is set as the initial torque of the electric motor 100 and the supply of electric power is started. Then, it progresses to step S301.

  Further, the process proceeds to step S402 after step S304, and the torque when the rotation of the internal combustion engine 1 is detected is stored (learned) in the ECU 60.

  As described above, according to the present embodiment, the time required for starting the internal combustion engine 1 can be shortened.

<Example 5>
In the above embodiment, the error in the cylinder air amount is corrected from the stop position of the piston 3. However, if a deposit adheres around the intake valve 11 and the deposit is sandwiched between the intake valves 11 when the intake valve 11 is opened and closed, for example, the intake valve 11 is in the same state as closing earlier, and the amount of air in the cylinder changes. To do. In this case, the in-cylinder air amount changes in the same manner as the lash adjuster 91 sinks. If there is a deposit, pre-ignition may occur. In this embodiment, it is determined whether the deposit is deposited or the lash adjuster 91 is sunk. Since other devices are the same as those in the first embodiment, the description thereof is omitted.

  Here, when the deposit adheres, the amount of in-cylinder air changes, so that the torque required to start the internal combustion engine 1 changes. Therefore, if the torque required to start the internal combustion engine 1 is equal to or greater than a predetermined value, it is determined that deposits that cause pre-ignition are attached to the cylinder, and control is performed to avoid pre-ignition. carry out.

  FIG. 15 is a flowchart showing a control flow when starting the internal combustion engine 1 according to this embodiment. This routine is executed by the ECU 60 when the internal combustion engine 1 is started. It is also executed for each cylinder. In addition, about the step where the same process as the said flow is made, the same code | symbol is attached | subjected and description is abbreviate | omitted.

  In this routine, after step S402, the process proceeds to step S501. In step S501, it is determined whether the torque required for starting the internal combustion engine 1 calculated in step S304 is less than a predetermined value. The predetermined value is a lower limit value of the torque necessary for starting the internal combustion engine 1 when a deposit exists in the cylinder. This value is obtained in advance by experiments or simulations and stored in the ECU 60. If an affirmative determination is made in step S501, the process proceeds to step S305. On the other hand, if a negative determination is made, the process proceeds to step S502.

  In step S502, it is determined that a deposit exists in the cylinder. In step S503, control for suppressing the occurrence of pre-ignition is performed. For example, the fuel injection amount is increased, and the temperature in the cylinder is reduced by the latent heat of vaporization.

  As described above, according to the present embodiment, it is possible to detect the occurrence of deposits in the cylinders, so that the occurrence of pre-ignition can be suppressed.

DESCRIPTION OF SYMBOLS 1 Internal combustion engine 2 Cylinder 3 Piston 4 Cylinder block 5 Connecting rod 6 Crankshaft 7 Cylinder head 9 Intake port 10 Intake pipe 11 Intake valve 12 Throttle 13 Exhaust port 14 Exhaust valve 36 Intake camshaft 36a Intake cam 60 ECU
61 Crank angle sensor 62 Accelerator pedal 63 Accelerator opening sensor 81 Rocker arm 81a Arm shaft 81b Bearing portion 91 Rush adjuster 92 Valve spring 100 Electric motor

Claims (7)

In a control device for an internal combustion engine, comprising: an electric motor that starts the internal combustion engine; and a lash adjuster that adjusts a valve clearance by supplying lubricating oil of the internal combustion engine.
A control apparatus for an internal combustion engine, comprising: a calculation unit that calculates a torque of the electric motor necessary for starting the internal combustion engine based on a sinking amount of the lash adjuster when the internal combustion engine is stopped.   The control device for an internal combustion engine according to claim 1, wherein the calculation unit calculates an air amount in a cylinder of the internal combustion engine based on a sink amount of the lash adjuster.   The calculation unit calculates a change amount of a valve timing of an intake valve based on a sink amount of a lash adjuster, and calculates an air amount in a cylinder of the internal combustion engine based on the change amount of the valve timing. 3. The control device for an internal combustion engine according to 2.   The control device for an internal combustion engine according to claim 2 or 3, wherein the calculation unit calculates a fuel supply amount into the cylinder based on an air amount in the cylinder of the internal combustion engine.   5. The control device for an internal combustion engine according to claim 1, wherein the calculation unit calculates a sink amount of the lash adjuster based on a stop position of the piston.   The control device for an internal combustion engine according to claim 5, wherein the calculation unit further calculates a sink amount of the lash adjuster based on a hydraulic pressure of the internal combustion engine and a stop time of the internal combustion engine.   The calculation unit calculates a change amount of the valve timing of the intake valve based on a sink amount of the lash adjuster, and calculates a torque of the electric motor necessary for starting the internal combustion engine based on the change amount of the valve timing. The control device for an internal combustion engine according to any one of claims 1 to 6, wherein the control device is calculated.

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