JP2007100580A - Frictional torque estimating device of internal combustion engine - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To improve estimating accuracy of frictional torque in an internal combustion engine. <P>SOLUTION: This frictional torque estimating device has a load state determining means 211B for determining a load state of the internal combustion engine 220, a cylinder internal pressure releasing means 211G for releasing cylinder internal pressure in a combustion chamber in a stable state of a load of the internal combustion engine 220 as a result of being determined by this load state determining means 211B, and a frictional torque estimating means 211A for estimating the frictional torque on the basis of angular acceleration of this crankshaft 36 by determining the angular acceleration of the crankshaft 36 in a state of releasing the cylinder internal pressure by this cylinder internal pressure releasing means 211G. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a friction torque estimating device for an internal combustion engine that can accurately estimate the friction torque generated in the internal combustion engine.

  In an internal combustion engine, friction is generated between a piston and a cylinder, a journal, a bearing, and the like, and this causes a friction torque as an element of momentum. This friction torque is generally correlated with the temperature of the lubricating oil between the piston and cylinder and the engine speed, but is not a linear correlation because it is a viscosity coefficient that changes under the influence of the temperature of the lubricating oil. Therefore, in general, the friction torque is calculated using a map or polynomial expression based on the water temperature and the engine speed.

  For example, Patent Document 1 below discloses a technique for estimating the indicated torque and the inertia torque in a stable state of the load of the internal combustion engine in which the load torque is “0”, and estimating the friction torque therefrom. . In Patent Document 1, the friction torque at a certain water temperature and engine speed is estimated, and the friction torque curve is calculated based on the difference between the new friction torque and the existing friction torque corresponding to the water temperature and the engine speed. It is offset.

  And in this patent document 1, the exact amount of rotation fluctuations etc. are calculated | required using the new friction torque curve, and the misfire determination with high precision is performed.

JP 2005-155612 A

  However, in Patent Document 1 described above, the friction torque is estimated from the indicated torque and inertia torque at a certain water temperature and engine speed, and the friction torque curve of the water temperature is offset using only this one point of friction torque. Friction torque at various engine speeds at the water temperature is estimated. For this reason, there is room for more accurate estimation than the friction torque that is the starting point when the friction torque curve is offset. For example, when the estimated accuracy of the indicated torque and the inertia torque itself is low, the accuracy of the friction torque estimated from these is also affected. If the estimation accuracy of the friction torque is improved, the accuracy of misfire determination can be improved.

  Accordingly, an object of the present invention is to provide a friction torque estimating device for an internal combustion engine that can improve the inconvenience of the conventional example and estimate the friction torque with high accuracy.

  In order to achieve the above object, according to the first aspect of the present invention, there is provided a load state determining means for determining the load state of the internal combustion engine, and a cylinder pressure releasing means for releasing the cylinder pressure while the load of the internal combustion engine is stable. And a friction torque estimating means for obtaining an angular acceleration of the crankshaft in a state where the in-cylinder pressure is released by the in-cylinder pressure releasing means and estimating a friction torque based on the angular acceleration.

  According to the friction torque estimating apparatus of the first aspect, the load torque and the indicated torque can be made “0” by releasing the in-cylinder pressure in a state where the load of the internal combustion engine is stable, and the angular acceleration From this, the friction torque can be estimated by obtaining the inertia torque.

  For example, the in-cylinder pressure releasing means is configured to control the throttle valve, the intake valve, and the exhaust valve so that the in-cylinder pressure is released, as in the second aspect of the invention. Specifically, as in the third aspect of the invention, the throttle valve, the intake valve, and the exhaust valve are configured to be fully opened to release the in-cylinder pressure.

  Here, the stable state of the load of the internal combustion engine is a state in which the clutch between the internal combustion engine and the transmission is disengaged as in the invention of claim 4, and more specifically, claim 5. As in the described invention, the clutch is disengaged when the constant speed shift is executed.

  The friction torque estimating apparatus for an internal combustion engine according to the present invention can estimate the friction torque by obtaining only the inertia torque based on the angular acceleration among the load torque, the indicated torque and the inertia torque as parameters when the friction torque is estimated. Thus, the estimation accuracy can be improved.

  Embodiments of a friction torque estimating apparatus for an internal combustion engine according to the present invention will be described below in detail with reference to the drawings. The present invention is not limited to the embodiments.

  First Embodiment A friction torque estimating apparatus for an internal combustion engine according to a first embodiment of the present invention will be described with reference to FIGS.

  In FIG. 1, reference numeral 11 denotes a friction torque estimating apparatus for an internal combustion engine in the first embodiment, and reference numeral 20 denotes an internal combustion engine that is a target for estimation of the friction torque Tf by the friction torque estimating apparatus 11. Although only one cylinder is illustrated in the internal combustion engine 20 of FIG. 1, a multi-cylinder internal combustion engine 20 such as two cylinders or six cylinders is illustrated here. Note that the friction torque estimation device 11 exemplified below may be applied to a single cylinder.

  First, the internal combustion engine 20 illustrated here will be described.

  The internal combustion engine 20 is subjected to combustion control and the like by an electronic control unit (ECU) 10 shown in FIG. The electronic control unit 10 includes a CPU (Central Processing Unit) (not shown), a ROM (Read Only Memory) that stores a predetermined control program in advance, a RAM (Random Access Memory) that temporarily stores the calculation results of the CPU, It is composed of a backup RAM or the like for storing information prepared in advance.

  First, the internal combustion engine 20 includes a cylinder head 22, a cylinder block 23, and a piston 24 that form a combustion chamber 21. Here, the cylinder head 22 and the cylinder block 23 are fastened with bolts or the like via the head gasket 25 shown in FIG. 1, and the recess 22 a on the lower surface of the cylinder head 22 formed thereby and the cylinder bore 23 a of the cylinder block 23. The piston 24 is disposed so as to be capable of reciprocating in the space. The combustion chamber 21 described above is constituted by a space surrounded by the wall surface of the recess 22 a of the cylinder head 22, the wall surface of the cylinder bore 23 a, and the top surface 24 a of the piston 24.

  Air from the outside is introduced into the combustion chamber 21 through the intake passage 26 and the intake port 22 b of the cylinder head 22.

  Here, an air cleaner 27 for removing foreign matters such as dust from the introduced external air and an air flow meter 28 for detecting the amount of intake air from the outside are provided on the intake passage 26. In the internal combustion engine 20, the detection signal of the air flow meter 28 is sent to the electronic control device 10, and the electronic control device 10 calculates the intake air amount from the outside based on the detection signal.

  A throttle valve 29 for adjusting the amount of intake air into the combustion chamber 21 and a throttle valve actuator 30 for opening and closing the throttle valve 29 are provided on the intake passage 26 downstream of the air flow meter 28. ing. The electronic control device 10 issues a control command for the valve opening angle of the throttle valve 29 to the throttle valve actuator 30 and causes the desired intake air amount corresponding to the valve opening angle to be sucked into the combustion chamber 21. The internal combustion engine 20 is provided with a throttle opening sensor 41 that detects the opening of the throttle valve 29, and a detection signal from the throttle opening sensor 41 is sent to the electronic control unit 10.

  On the other hand, one end of the intake port 22b opens into the combustion chamber 21, and an intake valve 31 that can open and close the opening is disposed at the opening. For this reason, when the intake valve 31 is opened, air is sucked into the combustion chamber 21 from the intake port 22b, while when the intake valve 31 is closed, the inflow of air into the combustion chamber 21 is blocked. Is done. The intake port 22b may have one or more openings into the combustion chamber 21, and an intake valve 31 is provided for each opening.

  Furthermore, in the internal combustion engine 20 of the first embodiment, a fuel injection device 32 that injects fuel into the intake port 22b is provided. In the fuel injection device 32, the fuel injection amount and the fuel injection timing are controlled by the electronic control device 10.

  For example, the electronic control device 10 according to the first embodiment controls the throttle valve actuator 30 and the fuel injection device 32 according to the operating state of the internal combustion engine 20 and the like, and mixes the air-fuel mixture having a desired mixing ratio into the combustion chamber 21. To supply. The electronic control unit 10 controls the ignition timing of the spark plug 33 shown in FIG. 1 and ignites the air-fuel mixture for combustion.

  The in-cylinder gas after the combustion is discharged from the combustion chamber 21 to the exhaust port 34 shown in FIG. An exhaust valve 35 that can open and close an opening between the exhaust port 34 and the combustion chamber 21 is disposed in the exhaust port 34. Therefore, the in-cylinder gas after combustion is discharged from the combustion chamber 21 to the exhaust port 34 by opening the exhaust valve 35, and the in-cylinder gas exhaust port 34 is closed by closing the exhaust valve 35. Is blocked. The number of openings into the combustion chamber 21 in the exhaust port 34 may be one or plural, and the exhaust valve 35 described above is provided for each opening.

  Furthermore, in the internal combustion engine 20 of the first embodiment, a crank angle sensor 42 that detects the rotation angle of the crankshaft 36, a water temperature sensor 43 that detects the temperature of the cooling water, and an oil temperature sensor 44 that detects the temperature of the lubricating oil. Various sensors such as an in-cylinder pressure sensor 45 for detecting the pressure in the combustion chamber 21 (in-cylinder pressure) are provided. The detection signals of these various sensors are also sent to the electronic control unit 10, respectively.

  Next, the friction torque estimating device 11 for estimating the friction torque Tf of the internal combustion engine 20 will be described in detail. The friction torque estimating device 11 of the first embodiment is provided as a function of the electronic control device 10 that performs the combustion control of the internal combustion engine 20 as described above.

  First, the torque of the internal combustion engine 20 will be described before referring to the friction torque estimating device 11. In general, known torques Ti, inertia torque, friction torque Tf, and load torque Tl are known as torques used in describing the internal combustion engine 20, and a relationship such as the following formula 1 is established among them. ing. In the equation 1, “J” represents the moment of inertia of the internal combustion engine 20, “dω / dt” represents the angular acceleration of the crankshaft 36, and “J × (dω / dt)” multiplied by these represents the inertia torque. ing.

  Therefore, the friction torque estimation device 11 of the first embodiment estimates the friction torque Tf using the equation 1, that is, using the indicated torque Ti, the inertia torque J × (dω / dt), and the load torque Tl. Friction torque estimating means 11A is provided.

  Here, the load torque Tl becomes “0” when the load of the internal combustion engine 20 becomes stable. Therefore, if the load of the internal combustion engine 20 can be stabilized, the friction torque estimating means 11A can determine the indicated torque Ti and the inertia torque J × (dω / dt) without obtaining the load torque Tl. The friction torque Tf can be obtained from the following equation 2 where the load torque Tl = 0 in the above equation 1.

  Therefore, in the first embodiment, load state determination means 11B for determining whether or not the load of the internal combustion engine 20 is in a stable state is provided in the friction torque estimating device 11, and it is determined that the load is in a stable state. When this is done, the friction torque estimating means 11A is configured to obtain the friction torque Tf.

  By the way, when the load of the internal combustion engine 20 is in a stable state, for example, (1) a clutch (not shown) that transmits a driving force between the internal combustion engine 20 and a transmission (not shown) is in a disconnected state. (2) When the engine speed Ne of the internal combustion engine 20 is stable, (3) When the internal combustion engine 20 is in a fuel cut state, or (4) The internal combustion engine 20 is starting (ie, cranking) The case where it is is considered.

  If the clutch is disengaged in the above (1), the load from the road surface due to wheel rotation fluctuation or the like is not input to the internal combustion engine 20, so the load of the internal combustion engine 20 is stabilized and the load torque Tl is set to "0". be able to. For example, if the clutch disengaged state is a vehicle of an automatic transmission, an instruction signal to the transmission when the electronic control device 10 performs an upshift or a downshift, and an electronic control device 10 issues a clutch disengagement command. This can be determined from the instruction signal to the clutch. On the other hand, in the case of a vehicle with a manual transmission, a signal indicating that the clutch is disengaged that is output to the electronic control device 10 when the driver depresses a clutch pedal (not shown) can be used.

  The stable state of the engine speed Ne in (2) above is, for example, an idling state. Here, the idling state often refers to a state in which the vehicle is stopped. Therefore, if the vehicle is in the idling state, a load from the road surface or the like is applied to the internal combustion engine as in (1) above. Therefore, the load of the internal combustion engine 20 is stabilized and the load torque Tl can be set to “0”. For example, the stable state of the engine speed Ne can be determined from the detection signal of the crank angle sensor 42. Here, the idling state refers to a state in which a constant idling rotational speed is maintained even for a short time.

  Further, in the fuel cut state of (3) above, since there is no load fluctuation due to combustion, the load of the internal combustion engine 20 can be stabilized and the load torque Tl can be set to “0”. For example, this fuel cut state can be determined from the presence / absence of an instruction signal to the fuel injection device 32 when the electronic control device 10 performs the fuel cut.

  Further, when cranking (4) is being performed, the crankshaft 36 is rotated only by the starter motor (not shown), so that the engine rotational speed Ne is stabilized, thereby stabilizing the load of the internal combustion engine 20. Thus, the load torque Tl can be set to “0”. For example, whether or not the cranking is being performed can be determined from an ON signal of a starter switch (not shown) input to the electronic control device 10.

  The load state determination unit 11B of the first embodiment is configured to determine whether or not the load of the internal combustion engine 20 is in a stable state based on all of (1) to (4) or at least one of them. can do.

  However, the friction torque Tf of the internal combustion engine 20 has a different value for each engine speed Ne as shown in a map of the friction torque Tf in FIG. 2 (hereinafter referred to as “friction torque map”). Even if the friction torque Tf is obtained in the stable state of the load determined based on (4), only the friction torque Tf at a specific engine speed Ne can be obtained.

  On the other hand, in the stable state of the load determined based on the above (1) or (3), the engine speed Ne fluctuates. Therefore, by obtaining the friction torque Tf a plurality of times while the load is stable. Information on a plurality of friction torques Tf at various engine speeds Ne can be obtained.

  Here, a vehicle equipped with a recent automatic transmission has a function of performing a so-called constant speed shift in order to reduce a shift shock during a downshift during deceleration (hereinafter referred to as “deceleration downshift”). It has been. As shown in FIG. 3, the constant speed shift means that when a deceleration downshift is performed from a certain shift stage n to a shift stage n−1, the engine speed Ne is increased after the clutch is disconnected by the electronic control unit 10 ( So-called blipping), and adjusting the engine speed Ne to the speed Nt of the input shaft of the transmission at the next gear stage n-1 and by engaging the clutch at that time, the shift shock is reduced. . Thus, during the constant speed shift period (between the time of clutch disengagement and the time of clutch engagement), the engine speed Ne is intentionally increased, so that the fluctuation range becomes larger, and more different engine speeds Ne. Thus, the friction torque Tf can be obtained.

  Therefore, the load state determination unit 11B of the first embodiment determines whether or not it is during the constant speed shift period during the deceleration downshift, and according to the result, whether or not the load of the internal combustion engine 20 is in a stable state. It is configured to determine whether or not. This load state determination means 11B determines the start time and end time of the constant speed shift period triggered by the clutch disengagement command and the clutch engagement command from the electronic control unit 10 to the clutch.

  By the way, in the first embodiment, an automatic transmission that is already provided with a constant speed shift function will be exemplified. For this reason, the electronic control device 10 of the first embodiment is provided with a constant speed shift execution device 12 for executing the constant speed shift as described above. For example, the constant speed shift execution device 12 controls the throttle valve actuator 30 to open the throttle valve 29 when the clutch is disengaged when performing a deceleration downshift.

  On the other hand, not all vehicles are equipped with an automatic transmission having a constant speed shift function. For this reason, in such a case, a constant speed shift execution means having the same function as that of the constant speed shift execution device 12 is provided in the friction torque estimation device 11, and the constant speed shift is performed when it is determined that it is during a deceleration downshift. To be executed.

  Further, the friction torque estimating device 11 of the first embodiment is provided with illustrated torque estimating means 11C for estimating the indicated torque Ti and inertia torque estimating means 11D for estimating the inertia torque J × (dω / dt). Yes. For this reason, the friction torque estimating means 11A of the first embodiment uses the above-described equation for the indicated torque Ti and the inertia torque J × (dω / dt) estimated by the indicated torque estimating means 11C and the inertia torque estimating means 11D, respectively. By substituting into 2, the friction torque Tf of the internal combustion engine 20 can be estimated.

  First, the indicated torque Ti is a sum of torque due to in-cylinder pressure (hereinafter referred to as “in-cylinder pressure torque”) Tp and torque due to reciprocating inertia mass (hereinafter referred to as “reciprocating inertia mass torque”) Tm.

  Here, in the internal combustion engine 20 of the first embodiment, an in-cylinder pressure sensor 45 is provided, and information on the in-cylinder pressure in the combustion chamber 21 is directly detected. Therefore, the indicated torque estimation means 11C of the first embodiment can determine the in-cylinder pressure torque Tp based on the detection signal from the in-cylinder pressure sensor 45.

  On the other hand, the reciprocating inertial mass torque Tm is determined in advance from the mass of the design value of the piston 24, and can be prepared in advance in the backup RAM or the like of the electronic control unit 10. However, the internal combustion engine 20 illustrated here is a multi-cylinder engine, and the reciprocating inertia mass torque Tm of the entire internal combustion engine 20 is “0” on average among the respective combustion cylinders.

  Therefore, in the first embodiment, the illustrated torque estimating means 11C is configured to estimate the illustrated torque Ti using only the in-cylinder pressure torque Tp without considering the reciprocating inertia mass torque Tm.

  If the internal combustion engine 20 is a single cylinder, information on the reciprocating inertia mass torque Tm is stored in a backup RAM or the like, and this is added to the in-cylinder pressure torque Tp to estimate the indicated torque Ti. The illustrated torque estimation means 11C is configured as described above.

  Subsequently, the inertia torque estimating means 11D will be described.

  The inertia torque estimating means 11D calculates inertia torque J × (dω / dt) by multiplying the moment of inertia J of the internal combustion engine 20 and the angular acceleration dω / dt of the crankshaft 36.

  Here, the moment of inertia J is determined in advance as a design value by mechanical parameters of each component such as the connecting rod and the crankshaft 36 constituting the internal combustion engine 20. For this reason, this moment of inertia J can be stored in a backup RAM or the like of the electronic control unit 10.

  On the other hand, the angular acceleration dω / dt of the crankshaft 36 can be obtained based on the detection signal of the crank angle sensor 42. The crank angle sensor 42 according to the first embodiment outputs a detection signal to the electronic control device 10 at a cycle of 10 ° CA, for example.

  For this reason, the inertia torque estimation means 11D estimates the inertia torque J × (dω / dt) from the detection signal from the crank angle sensor 42 and the information on the inertia moment J stored in the backup RAM. Can do.

  As described above, the friction torque estimating means 11A according to the first embodiment is configured so that the indicated torque Ti estimated based on the detection signal of the in-cylinder pressure sensor 45, information on the moment of inertia J prepared in advance in the backup RAM, and the crank angle. The friction torque Tf of the internal combustion engine 20 is estimated from the angular acceleration dω / dt of the crankshaft 36 obtained based on the detection signal of the sensor 42.

  Furthermore, in the friction torque estimation device 11 of the first embodiment, the friction torque information update for updating the friction torque Tf estimated by the friction torque estimation means 11A as the latest high accuracy according to the current internal combustion engine 20 is performed. Means 11E are provided.

  For example, in the first embodiment, the above-described friction torque map shown in FIG. 2 is prepared in advance in a backup RAM or the like, and this friction torque map is updated to the latest information.

  Here, as described above, the friction torque Tf of the internal combustion engine 20 has a characteristic that the value differs for each engine speed Ne. On the other hand, even if the engine speed Ne is the same, the cooling water temperature (or lubricating oil temperature) is the same. If they are different, the value is different depending on the cooling water temperature (or lubricating oil temperature).

  Therefore, for the friction torque information update unit 11E of the first embodiment, information on the engine speed Ne and the cooling water temperature (or lubricating oil temperature) at the time of estimation of the friction torque Tf by the friction torque estimation unit 11A is acquired. Thus, the information on the friction torque Tf on the friction torque map corresponding to the engine speed Ne and the coolant temperature (or the lubricating oil temperature) is replaced with a new one estimated by the friction torque estimating means 11A.

In the following, the existing friction torque Tf on the friction torque map is expressed as friction torque Tf _now, and the new friction torque Tf estimated by the friction torque estimating means 11A is expressed as friction torque Tf _new .

  Hereinafter, the operation of the friction torque estimating apparatus 11 according to the first embodiment will be described based on the flowcharts of FIGS. 4 and 5.

  First, the friction torque estimating apparatus 11 determines whether or not it is during the constant speed shift period at the time of the deceleration downshift by the load state determination means 11B (step ST1).

Here, if it is not during the constant speed shift period during the deceleration downshift, the process returns to step ST1 and the same determination is repeated. On the other hand, during the constant speed shift period during the deceleration downshift, the clutch is disengaged and the load torque Tl becomes “0”. Therefore, the friction torque estimating device 11 causes the friction torque estimating means 11A to estimate the friction torque Tf _new of the internal combustion engine 20 (step ST2).

  Specifically, in step ST2, as shown in the flowchart of FIG. 5, detection signals from the in-cylinder pressure sensor 45 and the crank angle sensor 42 are acquired (step ST2A).

  Then, the friction torque estimating device 11 uses the indicated torque estimating means 11C based on the detection signal (that is, information on the in-cylinder pressure in the combustion chamber 21) of the in-cylinder pressure sensor 45 of all cylinders acquired in step ST2A. The in-cylinder pressure torque Tp of the entire internal combustion engine 20 is calculated and estimated as the indicated torque Ti (step ST2B).

  Further, the friction torque estimating device 11 calculates the angular acceleration dω / dt of the crankshaft 36 from the detection signal of the crank angle sensor 42 acquired in step ST2A from the inertia torque estimating means 11D, and the electronic control device. The information on the moment of inertia J is read from the backup RAM 10 and multiplied by these to estimate the inertia torque J × (dω / dt) (step ST2C).

Thereafter, the friction torque estimating means 11A estimates the friction torque Tf _new of the internal combustion engine 20 by substituting the indicated torque Ti and the inertia torque J × (dω / dt) into the above-described equation 2 (step ST2D).

After estimating the friction torque Tf _new in this way, the friction torque estimating device 11 rewrites the friction torque map by the friction torque information updating means 11E (step ST3).

Specifically, the friction torque information updating unit 11E detects the cooling water temperature (or the lubricating oil temperature) from the water temperature sensor 43 (or the oil temperature sensor 44), and also detects the crank angle sensor 42 acquired in step ST2A. Based on the signal, the engine speed Ne is calculated. Then, the friction torque information update unit 11E, the cooling water temperature (or the lubricating oil temperature) and engine speed friction torque Tf _{new new} to the friction torque Tf _now on the corresponding friction torque map in the Ne estimated in step ST2 And replace the friction torque map.

The friction torque estimation device 11 according to the first embodiment repeats the above-described friction torque estimation processing and friction torque map rewriting processing in steps ST2 and ST3 many times until the constant speed shift ends (that is, until the clutch is engaged). . For example, the friction torque estimation device 11 may repeatedly estimate a _new friction torque Tf _new until the constant speed shift period ends each time rewriting of the friction torque map is completed. Further, the friction torque estimating device 11 may be configured to estimate a _new friction torque Tf _new after elapse of a predetermined time during the constant speed shift period, and a predetermined number of rotations from the engine speed Ne at the time of the previous estimation. A new friction torque Tf _new may be estimated when it fluctuates only.

Thus, for example, as shown in FIG. 6, the friction torque Tf _now at each point Ne1 to Ne5 at a water temperature of 60 ° C. on the friction torque map is changed to a _new friction torque Tf _new .

  Here, the friction torque estimating apparatus 11 of the first embodiment once ends the operation after finishing the constant speed shift period. However, the determination in step ST1 is repeatedly executed during engine start, and the like at the time of deceleration downshift or the like. Every time it is determined that the speed shift period is in progress, the calculation processes of ST2 and ST3 are performed. Note that the determination in step ST1 may be performed repeatedly at all times during engine startup, or may be performed again after a predetermined time has elapsed.

  As described above, according to the friction torque estimating device 11 of the first embodiment, the friction torque Tf is estimated during the constant speed shift period during the deceleration downshift where the load is stable, so that the estimation accuracy is improved. be able to. Further, since the friction torque Tf is estimated during the constant speed shift period during the deceleration downshift in which the engine speed Ne is changing, a plurality of accurate friction torques Tf corresponding to various engine speeds Ne are estimated. can do.

  In the first embodiment, for the sake of convenience, the friction torque estimating means 11A, the indicated torque estimating means 11C, and the inertia torque estimating means 11D are separated, but the indicated torque estimating means 11C and the inertia torque estimating means 11D. The friction torque estimation means 11A may be provided with the above calculation processing function, and the friction torque estimation means 11A may estimate the indicated torque Ti and the inertia torque J × (dω / dt).

  Next, a second embodiment of the internal combustion engine friction torque estimating apparatus according to the present invention will be described with reference to FIGS.

  In FIG. 7, reference numeral 111 denotes a friction torque estimating apparatus for an internal combustion engine in the second embodiment, and reference numeral 120 denotes an internal combustion engine that is a target for estimation of the friction torque Tf by the friction torque estimating apparatus 111. Also in the second embodiment, the friction torque estimating device 111 is provided as a function of the electronic control device 10. Also, the internal combustion engine 120 of FIG. 7 also shows only one cylinder as in the first embodiment, but here, an example of a multi-cylinder internal combustion engine 120 such as two cylinders or six cylinders is illustrated. Note that the friction torque estimation device 111 exemplified below may be applied to a single cylinder.

  Here, the internal combustion engine 120 of the second embodiment is different from the internal combustion engine 20 of the first embodiment only in that the in-cylinder pressure sensor 45 is not provided, and is otherwise the same as the internal combustion engine 20 of the first embodiment. It is configured.

  As described above, in the internal combustion engine 120 that does not include the in-cylinder pressure sensor 45, the in-cylinder pressure in the combustion chamber 21 cannot be detected directly, so that the in-cylinder pressure torque Tp cannot be obtained from the in-cylinder pressure. The indicated torque Ti cannot be estimated by the same method as in the first embodiment.

  Therefore, in the friction torque estimating device 111 of the second embodiment, illustrated torque estimating means 111C for estimating the in-cylinder pressure torque Tp from the engine speed Ne and the load factor (how much air enters the cylinder). Is provided.

  Also in the second embodiment, the internal combustion engine 120 is of a multi-cylinder type, and the reciprocating inertia mass torque Tm of the entire internal combustion engine 120 averaged between the respective combustion cylinders becomes “0”. 111 estimates the indicated torque Ti using only the in-cylinder pressure torque Tp without considering the reciprocating inertial mass torque Tm. On the other hand, when the internal combustion engine 120 is a single cylinder, information on the reciprocating inertia mass torque Tm is stored in a backup RAM or the like, and this is added to the in-cylinder pressure torque Tp to estimate the indicated torque Ti. .

  Here, when the in-cylinder pressure torque Tp is obtained using the engine speed Ne and the load factor as described above, if the combustion is performed in the combustion chamber 21, the accuracy of the obtained in-cylinder pressure torque Tp decreases. End up. For this reason, the friction torque estimating device 111 of the second embodiment is provided with fuel cut means 111F that performs fuel cut on all cylinders when the friction torque Tf is estimated.

  Further, the friction torque estimation device 111 of the second embodiment includes a friction torque that is configured in the same manner as the friction torque estimation means 11A, load state determination means 11B, inertia torque estimation means 11D, and friction torque information update means 11E of the first embodiment. A torque estimation unit 111A, a load state determination unit 111B, an inertia torque estimation unit 111D, and a friction torque information update unit 111E are also provided.

  Hereinafter, the operation of the friction torque estimating apparatus 111 according to the second embodiment will be described based on the flowcharts of FIGS. 8 and 9.

  First, the friction torque estimating apparatus 111 according to the second embodiment determines whether or not it is during the constant speed shift period during the deceleration downshift by the load state determination unit 111B as in the first embodiment (step ST11). If the determination is negative, the process returns to step ST11 and the same determination is repeated.

On the other hand, if the determination is affirmative, the friction torque estimating device 111 causes the fuel cut means 111F to perform fuel cut on all the cylinders (step ST12), and the friction torque estimating means 111A causes the friction torque Tf _{new of the} internal combustion engine 120 to run. Is estimated (step ST13).

  Specifically, in step ST13, as shown in the flowchart of FIG. 9, detection signals from the air flow meter 28 and the crank angle sensor 42 are acquired (step ST13A).

  The friction torque estimating device 111 calculates a load factor based on the detection signal (that is, information on the intake air amount) of the air flow meter 28 acquired in step ST13A by the indicated torque estimating unit 111C, and this load factor. From this, the in-cylinder pressure torque Tp of the entire internal combustion engine 120 is estimated and estimated as the indicated torque Ti (step ST13B).

Further, as in the first embodiment, the friction torque estimating device 111 estimates the inertia torque J × (dω / dt) from the inertia torque estimating means 111D (step ST13C), and the inertia torque J × (dω / dt). ) And the indicated torque Ti are substituted into the above equation 2 to estimate the friction torque Tf _new of the internal combustion engine 120 (step ST13D).

After the friction torque Tf _new is estimated in this way, the friction torque estimation device 111 rewrites the friction torque map by the friction torque information update unit 111E as in the first embodiment (step ST14). .

  Even in the second embodiment, the friction torque estimation device 111 performs the fuel cut process, the friction torque estimation process, and the friction torque map rewriting process in steps ST12 to ST14 described above until the constant speed shift is completed (that is, the clutch is engaged). Repeat as many times as you like).

  Thereby, also in the second embodiment, for example, the friction torque map shown in FIG. 3 is updated to the one shown in FIG.

  As described above, the friction torque estimating apparatus 111 according to the second embodiment can also estimate a plurality of highly accurate friction torques Tf corresponding to various engine speeds Ne, so that it is the same as in the first embodiment. The effect of can be produced.

  Even in the second embodiment, for the sake of convenience, the friction torque estimating means 111A, the illustrated torque estimating means 111C, and the inertia torque estimating means 111D are separated, respectively, but the indicated torque estimating means 111C and the inertia torque estimating means 111D. The friction torque estimating means 111A may be provided with the above arithmetic processing function, and the friction torque estimating means 111A may estimate the indicated torque Ti and the inertia torque J × (dω / dt).

  Next, a third embodiment of the friction torque estimating apparatus for an internal combustion engine according to the present invention will be described with reference to FIGS.

  In FIG. 10, reference numeral 211 denotes a friction torque estimating apparatus for an internal combustion engine in the third embodiment, and reference numeral 220 denotes an internal combustion engine that is a target for estimation of the friction torque Tf by the friction torque estimating apparatus 211. Also in the third embodiment, the friction torque estimating device 211 is provided as a function of the electronic control device 10. Also, the internal combustion engine 220 of FIG. 10 also shows only one cylinder as in the first and second embodiments, but here, an example of a multi-cylinder internal combustion engine 220 such as two cylinders or six cylinders is illustrated. . Note that the friction torque estimation device 211 exemplified below may be applied to a single cylinder.

  In the first and second embodiments, the in-cylinder pressure torque Tp is estimated to obtain the indicated torque Ti, and the indicated torque Ti and the inertia torque J × (dω / dt) are used to determine the friction torque of the internal combustion engine 220. Tf is estimated.

  However, if the in-cylinder pressure in the combustion chamber 21 becomes “0”, the in-cylinder pressure torque Tp also becomes “0”, and the following is described using only the inertia torque J × (dω / dt) without considering the indicated torque Ti. Friction torque Tf can be estimated from Equation (3).

  In the third embodiment, therefore, the in-cylinder pressure releasing means 211G that releases the in-cylinder pressures of all the cylinders to “0” when the friction torque Tf is estimated is provided in the friction torque estimation device 211.

  By the way, in order to set the in-cylinder pressure in the combustion chamber 21 to “0”, it is necessary to prevent a positive pressure and a negative pressure from being applied to the combustion chamber 21. For this reason, it is necessary to fully open the throttle valve 29 and to fully open both the intake valve 31 and the exhaust valve 35 at the same time.

  Here, the throttle valve 29 can be easily fully opened by controlling the throttle valve actuator 30. Therefore, the cylinder pressure releasing means 211G is configured to control the throttle valve actuator 30 to fully open the throttle valve 29 when estimating the friction torque Tf.

  On the other hand, the intake valve 31 and the exhaust valve 35 cannot be fully opened at the same time unless a special mechanism for arbitrarily operating them is provided. For this reason, the internal combustion engine 220 of the third embodiment is provided with an intake valve actuator 37 that can operate the intake valve 31 at an arbitrary lift amount at an arbitrary timing, and also an exhaust valve 35 at an arbitrary timing. An exhaust valve actuator 38 is provided that can be actuated in quantity.

  The in-cylinder pressure releasing means 211G is configured to control the intake valve actuator 37 and the exhaust valve actuator 38 when estimating the friction torque Tf so that the intake valve 31 and the exhaust valve 35 are fully opened simultaneously.

  Further, it is not preferable that fuel injection or ignition is performed when releasing the in-cylinder pressure. For this reason, the fuel cut means 211F similar to that of the second embodiment is provided in the friction torque estimating apparatus 211 of the third embodiment, and the fuel cut is executed when the in-cylinder pressure is released.

  Further, the friction torque estimating device 211 of the third embodiment is also provided with a friction torque estimating means 211A, a load state determining means 211B, and a friction torque information updating means 211E configured in the same manner as in the first and second embodiments.

  Here, in the third embodiment, since it is not necessary to estimate the indicated torque Ti by providing the in-cylinder pressure releasing means 211G as described above, the friction torque estimating device 211 is provided in the first and second embodiments. The illustrated torque estimation means 11C and 111C are not required. In the third embodiment, since the friction torque Tf can be estimated only from the inertia torque J × (dω / dt), it is provided in the first and second embodiments for simplifying the arithmetic processing. Inertia torque estimating means 11D and 111D are not prepared, and friction torque estimating means 211A is directly calculated.

  Further, as in the second embodiment, the internal combustion engine 220 need not include the in-cylinder pressure sensor 45. Therefore, the internal combustion engine 220 of the third embodiment is newly provided with an intake valve actuator 37 and an exhaust valve actuator 38 without including the in-cylinder pressure sensor 45 as compared with the internal combustion engine 20 of the first embodiment. The internal combustion engine 220 according to the third embodiment is configured in the same manner as the internal combustion engine 20 according to the first embodiment except for the differences.

  Hereinafter, the operation of the friction torque estimating apparatus 211 in the third embodiment will be described based on the flowchart of FIG.

  First, the friction torque estimating apparatus 211 of the third embodiment determines whether or not it is during the constant speed shift period during the deceleration downshift by using the load state determination unit 211B as in the first and second embodiments (step). If a negative determination is made in ST21), the process returns to step ST21 and the same determination is repeated.

  On the other hand, if the determination is affirmative, the friction torque estimating device 211 causes the fuel cut means 211F to perform fuel cut for all the cylinders (step ST22), and further controls the throttle valve 29 and the cylinder pressure release means 211G. All the intake valves 31 and the exhaust valves 35 of all the cylinders are simultaneously fully opened (step ST23).

As a result, the in-cylinder pressure of the combustion chamber 21 becomes “0” and the indicated torque Ti becomes “0”. _new is estimated (step ST24). Specifically, the friction torque estimating means 211A calculates the angular acceleration dω / dt of the crankshaft 36 from the detection signal of the crank angle sensor 42, and reads the information of the moment of inertia J from the backup RAM of the electronic control unit 10, By substituting these into equation 3 above, the friction torque Tf _new is estimated.

After estimating the friction torque Tf _new as described above, the friction torque estimating device 211 rewrites the friction torque map by the friction torque information updating means 211E, similarly to the first and second embodiments (step S1). ST25).

  Even in the third embodiment, the friction torque estimating apparatus 211 performs the fuel cut process, the in-cylinder pressure releasing process, the friction torque estimating process, and the friction torque map rewriting process in steps ST22 to ST25 described above until the constant speed shift ends ( Repeat until the clutch is engaged.

  Thereby, also in the third embodiment, for example, the friction torque map shown in FIG. 3 is updated to the one shown in FIG.

  As described above, according to the friction torque estimating device 211 of the third embodiment, it is not necessary to consider the indicated torque Ti as an estimated value when estimating the friction torque Tf. A plurality of friction torques Tf corresponding to can be estimated.

  Below, the specific application example of the friction torque Tf estimated by the friction torque estimation apparatus 11, 111, 211 of each Example 1-3 mentioned above is illustrated. For example, in the following, a case where the friction torque Tf is used when determining the misfire of the internal combustion engine will be described. For this reason, the electronic control device 10 of each of the first to third embodiments is provided with a misfire determination device 13 that determines the presence or absence of misfire in the internal combustion engine 20 (120, 220).

  First, the misfire determination device 13 of Application Example 1 will be described. The misfire determination device 13 determines the presence or absence of misfire based on whether or not the rotational fluctuation amount ΔN of the internal combustion engine 20 (120, 220) is equal to or greater than the misfire determination reference value Nb.

  The misfire determination reference value Nb is determined in advance as a misfire determination map using the engine speed Ne and load (load torque Tl) as operating parameters. The misfire determination device 13 reads, for example, the engine speed Ne obtained from the detection signal of the crank angle sensor 42 for each ignition, and determines the engine speed Ne at the previous ignition and the engine speed Ne at the current ignition. From this difference, a function for reading a predetermined misfire determination map from the backup RAM according to the operating state such as the coolant temperature of the internal combustion engine 20 (120, 220), and the misfire determination map A function for reading the misfire determination reference value Nb corresponding to the engine speed Ne and the load at the time of ignition this time and comparing the rotation fluctuation amount ΔN to determine the presence or absence of misfire is provided.

  Here, in the misfire determination map, the correspondence relationship between the engine speed Ne, the load, and the misfire determination reference value Nb is predetermined based on design values and experimental values at the time of vehicle development. For this reason, when the friction torque Tf is changed due to deterioration of the lubricating oil or the like, an accurate and accurate misfire determination cannot be performed unless the change amount is added to the misfire determination map.

  Therefore, the misfire determination device 13 of this application example 1 is provided with a function of correcting the rotational fluctuation amount ΔN with the latest friction torque map rewritten by the friction torque estimation device 11 (111, 211). A misfire determination is performed by comparing the corrected rotational fluctuation amount ΔN with the misfire determination reference value Nb. Thereby, even if the friction torque Tf fluctuates due to deterioration of the lubricating oil or the like, highly accurate misfire detection can be performed in consideration of the fluctuating friction torque Tf.

  The misfire determination device 13 of this application example 1 operates as shown in the flowchart of FIG.

  First, the misfire determination device 13 reads the engine speed Ne obtained from the detection signal of the crank angle sensor 42 for each ignition, and the difference between the engine speed Ne at the previous ignition and the engine speed Ne at the current ignition. From this, the rotational fluctuation amount ΔN is calculated (step ST31). Then, based on the engine speed Ne at the time of ignition and the coolant temperature, the corresponding friction torque Tf is read from the friction torque map of the backup RAM (step ST32), and the rotational fluctuation amount ΔN is corrected using this friction torque Tf. Is performed (step ST33).

  Subsequently, the misfire determination device 13 reads out a misfire determination map corresponding to the operation state from the backup RAM (step ST34), and the misfire determination corresponding to the engine speed Ne and the load at the time of the current ignition from the misfire determination map. The reference value Nb is read (step ST35).

  Thereafter, the misfire determination device 13 determines whether or not the corrected rotational fluctuation amount ΔN is larger than the misfire determination reference value Nb (step ST36).

  Here, the misfire determination device 13 determines that the corrected rotation fluctuation amount ΔN is normal if the corrected rotation fluctuation amount ΔN is equal to or less than the misfire determination reference value Nb, and terminates the present process, and the corrected rotation fluctuation amount ΔN determines the misfire determination. If it is larger than the reference value Nb, it is determined that misfire has occurred (step ST37).

  As described above, the misfire determination device 13 obtains an accurate rotational fluctuation amount (momentum) ΔN using the accurate and accurate friction torque Tf obtained by the friction torque estimating device 11 (111, 211). The accuracy of misfire detection can be improved.

  The misfire detection method in the misfire determination device 13 of the application example 1 may be any method as long as it is based on the rotational fluctuation amount.

  Next, an application example 2 in which the misfire determination device 13 is changed as follows will be described.

  The misfire determination device 13 is provided with a function of correcting the misfire determination reference value Nb read at the time of misfire determination with the latest friction torque map rewritten by the friction torque estimation device 11 (111, 211). . For this reason, the misfire determination device 13 uses the corrected misfire determination reference value Nb for comparison with the rotational fluctuation amount ΔN. Even if the friction torque Tf fluctuates due to deterioration of the lubricating oil, It is possible to perform misfire detection with high accuracy in consideration of the changed friction torque Tf.

  The misfire determination device 13 has a function for calculating the rotational fluctuation amount ΔN, a function for reading a predetermined misfire determination map, a function for reading the misfire determination reference value Nb from the misfire determination map, and the misfire determination reference value Nb and the rotational fluctuation amount. This is the same as Application Example 1 in that it has a misfire determination function based on comparison with ΔN.

  The misfire determination device 13 of this application example 2 operates as shown in the flowchart of FIG.

  First, the misfire determination device 13 reads the engine speed Ne obtained from the detection signal of the crank angle sensor 42 for each ignition, and the difference between the engine speed Ne at the time of previous ignition and the engine speed Ne at the time of current ignition. From this, the rotational fluctuation amount ΔN is calculated (step ST41). Then, the misfire determination map is read from the backup RAM (step ST42), and the misfire determination reference value Nb corresponding to the engine speed Ne and the load at the time of this ignition is read from the misfire determination map (step ST43).

  Thereafter, the misfire determination device 13 reads the corresponding friction torque Tf from the friction torque map of the backup RAM based on the engine speed Ne of the misfire determination reference value Nb and the coolant temperature at the time of this ignition (step ST44). ). Then, the misfire determination reference value Nb is corrected using the friction torque Tf (step ST45), and it is determined whether or not the rotational fluctuation amount ΔN is larger than the corrected misfire determination reference value Nb (step ST46). ).

  Here, if the rotational fluctuation amount ΔN is equal to or less than the corrected misfire determination reference value Nb, the misfire determination device 13 determines that the rotation is normal and ends the present process. If it is larger than the determination reference value Nb, it is determined that a misfire has occurred (step ST47).

  As described above, the misfire determination device 13 corrects the misfire determination reference value Nb using the accurate and accurate friction torque Tf obtained by the friction torque estimation device 11 (111, 211). The accuracy of detection can be improved.

  Next, an application example 3 in which the misfire determination device 13 is changed as follows will be described.

  Unlike the application examples 1 and 2, the misfire determination device 13 here is configured to determine the presence or absence of misfire using the estimated torque fluctuation amount ΔT representing the operating state of the internal combustion engine 20 (120, 220) as a parameter. ing.

  First, the misfire determination device 13 of this application example 3 reads, for example, the angular acceleration dω / dt of the crankshaft 36 obtained from the detection signal of the crank angle sensor 42 for each ignition, and obtains the angular acceleration dω / dt at the previous ignition. A function of calculating the estimated torque fluctuation amount ΔT from the difference between the estimated torques T obtained from the angular acceleration dω / dt at the time of ignition this time is provided.

  Here, instead of the misfire determination map for deriving the misfire determination reference value Nb described above, a misfire determination map for deriving the misfire determination reference value Tb using the engine speed Ne and load (load torque Tl) as operating parameters is prepared in advance. Yes. For this reason, in the misfire determination device 13 here, a predetermined misfire determination map is read from the backup RAM in accordance with the operation state such as the coolant temperature of the internal combustion engine 20 (120, 220), and the read misfire determination map is read. Misfire determination is performed using the acquired misfire determination reference value Tb.

  On the other hand, in the misfire determination map, the correspondence relationship between the engine speed Ne, the load, and the misfire determination reference value Tb is predetermined as a predetermined value based on design values and experimental values at the time of vehicle development. When the friction torque Tf changes due to deterioration or the like, the change amount is not taken into account in the misfire determination map, and accurate misfire determination cannot be performed accurately.

  Therefore, the misfire determination device 13 corrects the estimated torque fluctuation amount ΔT with the latest friction torque map rewritten by the friction torque estimation device 11 (111, 211), and the corrected estimated torque fluctuation amount ΔT and the misfire. The misfire determination is performed by comparing the determination reference value Tb. As a result, even if the friction torque Tf fluctuates due to deterioration of the lubricating oil or the like, the misfire determination device 13 can perform misfire detection with high accuracy in consideration of the fluctuating friction torque Tf.

  For this reason, the misfire determination device 13 has a function for correcting the estimated torque fluctuation amount ΔT and a misfire determination criterion corresponding to the engine speed Ne and the load at the time of this ignition from the read misfire determination map. A function is provided for reading the value Tb and determining the presence or absence of misfire by comparing the misfire judgment reference value Tb with the corrected estimated torque fluctuation amount ΔT.

  The misfire determination device 13 of this application example 3 operates as shown in the flowchart of FIG.

  First, the misfire determination device 13 reads the angular acceleration dω / dt obtained from the detection signal of the crank angle sensor 42 for each ignition, and the angular acceleration dω / dt at the previous ignition and the angular acceleration dω / dt at the current ignition. The estimated torque fluctuation amount ΔT is calculated from the difference between the estimated torques T obtained from (step ST51). Then, based on the engine speed Ne at the time of ignition and the coolant temperature, the corresponding friction torque Tf is read from the friction torque map of the backup RAM (step ST52), and the estimated torque fluctuation amount ΔT is calculated using this friction torque Tf. Correction is performed (step ST53).

  Subsequently, the misfire determination device 13 reads out a misfire determination map corresponding to the operation state from the backup RAM (step ST54), and from this misfire determination map, the misfire determination corresponding to the engine speed Ne and the load at the time of the current ignition. The reference value Tb is read (step ST55).

  Thereafter, the misfire determination device 13 determines whether or not the corrected estimated torque fluctuation amount ΔT is larger than the misfire determination reference value Tb (step ST56).

  Here, if the corrected estimated torque fluctuation amount ΔT is equal to or smaller than the misfire determination reference value Tb, the misfire determination device 13 determines that the corrected estimated torque fluctuation amount ΔT is normal, ends the present process, and corrects the corrected estimated torque fluctuation amount ΔT. Is greater than the misfire determination reference value Tb, it is determined that misfire has occurred (step ST57).

  As described above, the misfire determination device 13 can obtain the accurate estimated torque fluctuation amount ΔT by using the accurate and accurate friction torque Tf obtained by the friction torque estimating device 11 (111, 211). The accuracy of misfire detection can be improved.

  Next, an application example 4 in which the misfire determination device 13 is changed as follows will be described.

  The misfire determination device 13 here has a function of correcting the misfire determination reference value Tb read at the time of misfire determination with the latest friction torque map rewritten by the friction torque estimation device 11 (111, 211). It has been. For this reason, in the misfire determination device 13, since the misfire determination reference value Tb after the correction is used for comparison with the estimated torque fluctuation amount ΔT, even if the friction torque Tf fluctuates due to deterioration of the lubricating oil or the like. The misfire detection can be performed with high accuracy in consideration of the changed friction torque Tf.

  The misfire determination device 13 of the application example 4 includes a function for calculating the estimated torque fluctuation amount ΔT, a function for reading a predetermined misfire determination map, a function for reading the misfire determination reference value Tb from the misfire determination map, and a misfire determination reference value. It is the same as the misfire determination device 13 of the application example 3 in that it has a misfire determination function based on a comparison between Tb and the estimated torque fluctuation amount ΔT.

  The misfire determination device 13 of this application example 4 operates as shown in the flowchart of FIG.

  First, the misfire determination device 13 calculates the estimated torque fluctuation amount ΔT in the same manner as Step ST51 of Application Example 3 (Step ST61). Then, the misfire determination map is read from the backup RAM (step ST62), and the misfire determination reference value Tb corresponding to the engine speed Ne and load (load torque Tl) at the time of the current ignition is read from the misfire determination map (step ST63). ).

  Thereafter, the misfire determination device 13 reads the corresponding friction torque Tf from the friction torque map of the backup RAM based on the engine speed Ne of the misfire determination reference value Tb and the coolant temperature at the time of this ignition (step ST64). ). Then, the misfire determination reference value Tb is corrected using the friction torque Tf (step ST65), and it is determined whether the estimated torque fluctuation amount ΔT is larger than the corrected misfire determination reference value Tb (step ST65). ST66).

  Here, the misfire determination apparatus 13 determines that the estimated torque fluctuation amount ΔT is normal if the estimated torque fluctuation amount ΔT is equal to or less than the corrected misfire determination reference value Tb, and ends the present process. The estimated torque fluctuation amount ΔT is corrected. If it is larger than the misfire determination reference value Tb, it is determined that a misfire has occurred (step ST67).

  As described above, the misfire determination device 13 corrects the misfire determination reference value Tb using the accurate and accurate friction torque Tf obtained by the friction torque estimation device 11 (111, 211). The accuracy of detection can be improved.

  As described above, the friction torque estimating apparatus for an internal combustion engine according to the present invention is useful for a technique for accurately estimating the friction torque.

It is a figure which shows the structure of Example 1 of the friction torque estimation apparatus of the internal combustion engine which concerns on this invention. It is a figure which shows an example of the friction torque map in the friction torque estimation apparatus of Example 1. FIG. It is a figure explaining the constant speed shift period. 3 is a flowchart illustrating the operation of the friction torque estimating device according to the first embodiment. 5 is a flowchart detailing a friction torque calculating operation of the friction torque estimating device according to the first embodiment. It is a figure which shows an example which woven the estimation result of the present Example 1 into the friction torque map of FIG. It is a figure which shows the structure of Example 2 of the friction torque estimation apparatus of the internal combustion engine which concerns on this invention. It is a flowchart which shows operation | movement description of the friction torque estimation apparatus in Example 2. FIG. 6 is a flowchart detailing a friction torque calculating operation of the friction torque estimating device according to the second embodiment. It is a figure which shows the structure of Example 3 of the friction torque estimation apparatus of the internal combustion engine which concerns on this invention. 12 is a flowchart illustrating the operation of the friction torque estimating device according to the third embodiment. It is a flowchart which shows operation | movement description of the misfire determination apparatus which is the application example 1 of the estimated friction torque. It is a flowchart which shows operation | movement description of the misfire determination apparatus which is the application example 2 of the estimated friction torque. It is a flowchart which shows operation | movement description of the misfire determination apparatus which is the application example 3 of the estimated friction torque. It is a flowchart which shows operation | movement description of the misfire determination apparatus which is the application example 4 of the estimated friction torque.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 Electronic controller 11, 111, 211 Friction torque estimation apparatus 11A, 111A, 211A Friction torque estimation means 11B, 111B, 211B Load state determination means 11C, 111C Illustrated torque estimation means 11D, 111D Inertia torque estimation means 11E, 111E, 211E Friction torque information update means 111F, 211F Fuel cut means 211G In-cylinder pressure release means 12 Constant speed shift execution device 20, 120, 220 Internal combustion engine 29 Throttle valve 30 Throttle valve actuator 31 Intake valve 32 Fuel injection device 33 Spark plug 35 Exhaust valve 36 Crankshaft 37 Intake valve actuator 38 Exhaust valve actuator 41 Throttle opening sensor 42 Crank angle sensor 45 In-cylinder pressure sensor

Claims (5)

Load state determination means for determining a load state of the internal combustion engine;
In-cylinder pressure releasing means for releasing the in-cylinder pressure in a state where the load of the internal combustion engine is stable,
Friction torque estimating means for obtaining angular acceleration of the crankshaft in a state where the cylinder pressure is released by the cylinder pressure releasing means, and estimating the friction torque based on the angular acceleration;
A friction torque estimating device for an internal combustion engine, comprising:   2. The friction torque estimating device for an internal combustion engine according to claim 1, wherein the in-cylinder pressure releasing means controls the throttle valve, the intake valve, and the exhaust valve so that the in-cylinder pressure is released.   3. A friction torque estimating apparatus for an internal combustion engine according to claim 2, wherein said in-cylinder pressure releasing means is configured to fully open said throttle valve, intake valve and exhaust valve.   The friction torque of the internal combustion engine according to claim 1, 2 or 3, wherein the stable state of the load of the internal combustion engine is a state in which a clutch between the internal combustion engine and the transmission is disengaged. Estimating device.   5. The friction torque estimating apparatus for an internal combustion engine according to claim 1, 2, 3, or 4, wherein the stable state of the load of the internal combustion engine is a clutch disengaged state during execution of a constant speed shift.

Images