JP2011247154A - Control device of internal combustion engine - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a control device of an internal combustion engine capable of performing accurate cylinder discrimination during the start of the internal combustion engine while reducing a load on an ECU executing cylinder discrimination as compared with a conventional device even if cylinder discrimination is performed on the basis of only a cam angle signal output from a cam angle sensor and shortening a time required for the start of the internal combustion engine.SOLUTION: The ECU determines whether an engine is started or not (a step S1) in a fail-safe state, adjusts the count value of a crank counter for F/S (step S2) on the basis of all edges of a G2In signal and a G2Ex signal when it is determined that the engine is started, adjusts the count value of the crank counter for F/S (a step S3) on the basis of an effective edge of the G2In signal when it is determined that the engine is not started and performs cylinder discrimination (a step S4) on the basis of the adjusted count value of the crank counter for F/S.

Description

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

  In general, a control device for an internal combustion engine mounted on a vehicle uses an ignition plug ignition based on a crank angle signal generated by a crank angle sensor that detects a rotation angle of a crankshaft as an output shaft of an engine constituting the internal combustion engine. Cylinder discrimination is performed to measure the control timing such as the timing and the fuel injection timing of the injector for each cylinder.

  As a control device for an internal combustion engine for performing such cylinder discrimination, when the crank angle signal is not normally obtained due to a failure of the crank angle sensor or the like, the rotation angles of the intake camshaft and the exhaust camshaft provided in the engine are determined. Based on the intake cam angle signal and the exhaust cam angle signal respectively detected by the intake cam angle sensor and the exhaust cam angle sensor that are detected respectively, those that are in a fail-safe state in which an ECU (Electronic Control Unit) performs cylinder discrimination are known. (For example, see Patent Documents 1 and 2).

  Therefore, in the control device for an internal combustion engine disclosed in Patent Document 1, the intake cam angle signal and the exhaust cam angle signal respectively generated by the intake cam angle sensor and the exhaust cam angle sensor are used as cylinder discrimination signals, respectively. However, during the output of one cylinder discrimination signal, a cylinder having the number of outputs of the other cylinder discrimination signal equal to or greater than a predetermined number is determined as a specific cylinder, and cylinders other than the specific cylinder are determined based on the determination result and the cylinder determination signal. It is to be determined.

  As a result, the control apparatus for an internal combustion engine disclosed in Patent Document 1 performs cylinder discrimination only with the intake cam angle signal and the exhaust cam angle signal respectively generated by the intake cam angle sensor and the exhaust cam angle sensor.

  Further, the control device for an internal combustion engine disclosed in Patent Document 2 uses the intake cam angle signal and the exhaust cam angle signal respectively generated by the intake cam angle sensor and the exhaust cam angle sensor as cylinder discrimination signals, respectively, The cylinder discriminating signal is input sequentially, the cycle between the cylinder discriminating signal inputs is measured, and the ratio of the latest measured cycle to the cycle measured last time and the sensor that has output the latest cylinder discrimination signal are the intake cams. A specific cylinder is discriminated based on whether it is an angle sensor or an exhaust cam angle sensor, and cylinders other than the specific cylinder are discriminated based on this discrimination result and a cylinder discrimination signal.

  As a result, the control apparatus for an internal combustion engine disclosed in Patent Document 2 performs cylinder discrimination only with the intake cam angle signal and the exhaust cam angle signal respectively generated by the intake cam angle sensor and the exhaust cam angle sensor.

JP 2001-234794 A JP 2001-234895 A

  However, in such a conventional control device for an internal combustion engine, when performing cylinder discrimination based on a cam angle signal such as an intake cam angle signal or an exhaust cam angle signal, the detected angle is greater than the crank angle signal. Since it is necessary to perform cylinder discrimination based on a cam angle signal having a long interval, the accuracy of cylinder discrimination is deteriorated during engine start with a low engine speed.

  Therefore, in the conventional control device for an internal combustion engine, since it takes time until the engine is started, in order to cause the ECU to acquire all the cylinder discrimination signals in order to execute the cylinder discrimination, the load on the ECU There was a problem that it would take.

  The present invention has been made to solve such a problem, and it relates to an ECU that executes cylinder discrimination even when cylinder discrimination is performed based only on a cam angle signal output from a cam angle sensor. Provided is a control device for an internal combustion engine that can perform cylinder discrimination with high accuracy while starting the internal combustion engine while reducing the load compared to the conventional one, and can reduce the time required for starting the internal combustion engine. For the purpose.

  In order to achieve the above object, the control device for an internal combustion engine according to the present invention includes: (1) a crank angle sensor that detects a rotation angle of a crankshaft and generates a crank angle signal; and a cam angle that detects a rotation angle of a camshaft. A control device for an internal combustion engine that controls an internal combustion engine based on the cam angle signal when the crank angle signal is normally obtained from the crank angle sensor. Edge acquisition means for acquiring an edge of the cam angle signal, pseudo-counting means for pseudo-counting the rotation angle of the crankshaft based on the edge acquired by the edge acquisition means, and a count value of the pseudo-counting means A cylinder discriminating unit for discriminating a cylinder based on the cam angle signal. It is configured to acquire the less edge than during starting of the internal combustion engine.

  With this configuration, during the start of the internal combustion engine, cylinder discrimination is performed by acquiring more cam angle signal edges after the internal combustion engine is started, so that accurate cylinder discrimination can be performed. The time required for starting can be shortened. On the other hand, after the internal combustion engine is started, cylinder discrimination is performed by acquiring fewer cam angle signal edges than during startup of the internal combustion engine, so that the load on the ECU constituting the cylinder discrimination means can be reduced.

  Therefore, the control device for an internal combustion engine according to the present invention has a higher load on the ECU that performs cylinder discrimination than the conventional one even when cylinder discrimination is performed based only on the cam angle signal output from the cam angle sensor. While being reduced, it is possible to perform cylinder discrimination with high accuracy while the internal combustion engine is being started, and it is possible to shorten the time required for starting the internal combustion engine.

  In the internal combustion engine control apparatus according to (1), (2) the edge acquisition unit may acquire all edges of the cam angle signal while the internal combustion engine is started. .

  With this configuration, the accuracy of cylinder discrimination can be improved by acquiring all the edges of the cam angle signal during the start of the internal combustion engine.

  Further, in the control device for an internal combustion engine according to the above (2), (3) the edge acquisition means, after starting the internal combustion engine, has crank angles at regular intervals among all the edges of the cam angle signal. The effective edge of the cam angle signal corresponding to each may be acquired.

  With this configuration, after starting the internal combustion engine, by acquiring only effective edges necessary for pseudo-counting the rotation angle of the crankshaft, the load on the ECU that performs cylinder discrimination is increased compared to the conventional one. Can be reduced.

  Further, in the control device for an internal combustion engine according to (1), (4) the cam angle sensor includes an intake cam angle sensor that detects a rotation angle of an intake cam shaft and generates an intake cam angle signal; An exhaust cam angle sensor that detects an angle of rotation of the shaft and generates an exhaust cam angle signal, and the edge acquisition means includes the intake cam angle signal and the exhaust cam angle signal during startup of the internal combustion engine. All of the edges may be acquired.

  With this configuration, the accuracy of cylinder discrimination can be improved by acquiring all the edges of the intake cam angle signal and the exhaust cam angle signal during the start of the internal combustion engine.

  In the control device for an internal combustion engine according to (1), (5) the cam angle sensor includes an intake cam angle sensor that detects an intake cam shaft rotation angle and generates an intake cam angle signal. The edge acquisition means may acquire all the edges of the intake cam angle signal during startup of the internal combustion engine.

  With this configuration, it is possible to improve the accuracy of cylinder discrimination by acquiring all the edges of the intake cam angle signal during startup of the internal combustion engine.

  Further, in the control device for an internal combustion engine according to (1), (6) the cam angle sensor includes an exhaust cam angle sensor that detects a rotation angle of an exhaust cam shaft and generates an exhaust cam angle signal, The edge acquisition means may acquire all edges of the exhaust cam angle signal during startup of the internal combustion engine.

  With this configuration, it is possible to improve the accuracy of cylinder discrimination by acquiring all the edges of the exhaust cam angle signal during startup of the internal combustion engine.

  Further, in the control device for an internal combustion engine according to the above (4) or (5), (7) the edge acquisition means, among all the edges of the intake cam angle signal after the start of the internal combustion engine, You may make it acquire the effective edge of the said intake cam angle signal corresponding to the crank angle of a fixed space | interval, respectively.

  With this configuration, after starting the internal combustion engine, only the effective edge of the intake cam angle signal necessary for pseudo-counting the rotation angle of the crankshaft is obtained, so that the load applied to the ECU that performs cylinder discrimination Can be reduced from the conventional one.

  Further, in the control device for an internal combustion engine according to the above (4) or (6), (8) the edge acquisition means, among all the edges of the exhaust cam angle signal after the start of the internal combustion engine, You may make it acquire the effective edge of the said exhaust cam angle signal corresponding to the crank angle of a fixed space | interval, respectively.

  With this configuration, after starting the internal combustion engine, only the effective edge of the exhaust cam angle signal necessary for pseudo-counting the rotation angle of the crankshaft is obtained, so that the load applied to the ECU that performs cylinder discrimination Can be reduced from the conventional one.

  According to the present invention, even when the cylinder discrimination is performed based only on the cam angle signal output from the cam angle sensor, the load applied to the ECU for executing the cylinder discrimination is reduced from the conventional one while reducing the load on the ECU. Thus, it is possible to provide a control apparatus for an internal combustion engine that can perform cylinder discrimination with high accuracy and can reduce the time required for starting the internal combustion engine.

1 is a functional block diagram showing a configuration of a vehicle equipped with a control device for an internal combustion engine according to an embodiment of the present invention. It is a schematic sectional drawing of the engine shown in FIG. FIG. 3 is a schematic perspective view of the engine shown in FIG. 2. It is a side view of the crank rotor provided in the crankshaft of the engine shown in FIG. It is a graph which shows the detection signal of the crank angle sensor provided in the engine shown in FIG. FIG. 4 is a side view of an intake cam rotor provided on an intake camshaft of the engine shown in FIG. 3. It is a graph which shows the detection signal of the intake cam angle sensor provided in the engine shown in FIG. It is a functional block diagram which shows the control part of the control apparatus of the internal combustion engine which concerns on one embodiment of this invention. 3 is a timing chart showing a relationship among a crank angle signal, an intake cam angle signal, an exhaust cam angle signal, and a crank counter in an ECU constituting the control apparatus for an internal combustion engine according to the embodiment of the present invention. A part of an intake cam angle signal referred to when an ECU constituting the control device for an internal combustion engine according to an embodiment of the present invention specifies an effective edge serving as a reference of a cam angle signal for a specific count value of a crank counter It is a timing chart which shows. Another intake cam angle signal referred to when an ECU constituting the control device for an internal combustion engine according to an embodiment of the present invention specifies an effective edge serving as a reference of a cam angle signal for a specific count value of a crank counter It is a timing chart which shows a part. Another intake cam angle signal referred to when an ECU constituting the control device for an internal combustion engine according to an embodiment of the present invention specifies an effective edge serving as a reference of a cam angle signal for a specific count value of a crank counter It is a timing chart which shows a part. An intake cam angle signal and an exhaust cam to be referred to when an ECU constituting the control device for an internal combustion engine according to an embodiment of the present invention specifies an effective edge serving as a reference of a cam angle signal for a specific count value of a crank counter It is a timing chart which shows a part relationship with an angle signal. An intake cam angle signal and an exhaust cam to be referred to when an ECU constituting the control device for an internal combustion engine according to an embodiment of the present invention specifies an effective edge serving as a reference of a cam angle signal for a specific count value of a crank counter It is a timing chart which shows the other partial relationship with an angle signal. An intake cam angle signal and an exhaust cam to be referred to when an ECU constituting the control device for an internal combustion engine according to an embodiment of the present invention specifies an effective edge serving as a reference of a cam angle signal for a specific count value of a crank counter It is a timing chart which shows the other partial relationship with an angle signal. 3 is a flowchart for illustrating a cylinder discrimination operation in a fail-safe state of an ECU constituting the control device for an internal combustion engine according to the embodiment of the present invention. 6 is a timing chart showing other relationships of a crank angle signal, an intake cam angle signal, an exhaust cam angle signal, and a crank counter in an ECU constituting the control apparatus for an internal combustion engine according to the embodiment of the present invention.

  Embodiments of the present invention will be described below with reference to the drawings.

  As shown in FIG. 1, a vehicle 10 in the present embodiment includes an engine 20 as a power source, a transmission 30 that transmits power generated in the engine 20 and changes a gear ratio in accordance with a traveling state of the vehicle 10, and the like. The differential mechanism 40 that distributes the power transmitted from the transmission 30 to the drive shafts 51L and 51R, the drive wheels 52L and 52R that are rotated by the power transmitted from the drive shafts 51L and 51R and drive the vehicle 10, and the vehicle ECU (Electronic Control Unit) 100 which controls each part of 10 collectively.

  As shown in FIG. 2, the engine 20 is constituted by an internal combustion engine, and includes a cylinder block 210, a cylinder head 220 fixed to the top of the cylinder block 210, and an oil pan 230 that stores oil, and a cylinder Each cylinder is formed by the block 210 and the cylinder head 220.

  In the present embodiment, the engine 20 is described as an inline 4-cylinder gasoline engine. However, in the present invention, an in-line 6-cylinder engine, a V-type 6-cylinder engine, and a V-type 12-cylinder are used. It may be constituted by various types of engines such as an engine or a horizontally opposed six-cylinder engine. Here, the engine 20 shown in FIG. 2 shows one cylinder 21 of four cylinders arranged in series.

  A piston 211 is accommodated in each cylinder 21 so as to be able to reciprocate. A combustion chamber 201 of each cylinder 21 is formed by the cylinder block 210, the cylinder head 220, and the piston 211.

  In the present embodiment, the engine 20 is constituted by a four-cycle gasoline engine that performs a series of four strokes including an intake stroke, a compression stroke, an expansion stroke, and an exhaust stroke while the piston 211 makes two reciprocations. Will be described.

  The engine 20 includes a crankshaft 213, and the crankshaft 213 is connected to the piston 211 housed in each cylinder 21 via a connecting rod 212. The connecting rod 212 converts the reciprocating motion of the piston 211 into the rotational motion of the crankshaft 213.

  Accordingly, the engine 20 transmits power to the transmission 30 by causing the piston 211 to reciprocate by burning the fuel / air mixture in the combustion chamber 201 and rotating the crankshaft 213 via the connecting rod 212. It is supposed to be. The fuel used for the engine 20 may be a hydrocarbon fuel such as gasoline or light oil, or an alcohol fuel obtained by mixing alcohol such as ethanol and gasoline.

  The engine 20 is introduced into the combustion chamber 201, an air cleaner 312 that cleans air that flows from outside the vehicle, an intake pipe 311 that is connected to the cylinder head 220 in order to introduce the purified air into the combustion chamber 201. A throttle valve 313 for adjusting the flow rate of air, a throttle sensor 135 for detecting the opening of the throttle valve 313, and a cylinder for discharging exhaust gas generated by combustion of the air-fuel mixture in the combustion chamber 201 to the outside of the vehicle An exhaust pipe 321 connected to the head 220 and a catalytic converter 322 provided in the exhaust pipe 321 for redox purification of harmful substances in the exhaust gas are provided.

  The air cleaner 312 is configured to remove foreign substances in the intake air by using, for example, a paper or synthetic fiber nonwoven fabric filter accommodated therein.

  The throttle valve 313 is constituted by a thin disc-like valve body, and includes a shaft at the center of the valve body. The throttle valve 313 is provided with a throttle valve actuator 314 that rotates the valve body by rotating the shaft in accordance with the control of the ECU 100 to change the flow rate of air in the intake pipe 311.

  The catalytic converter 322 generally includes a three-way catalyst that can efficiently remove harmful substances such as unburned hydrocarbons (HC), carbon monoxide (CO), and nitrogen oxides (NOx) contained in the exhaust gas. ing. As this three-way catalyst, a catalyst having a function of efficiently removing NOx even from exhaust gas having a high NOx content is preferably used.

  The cylinder head 220 is formed with an intake port 221 for communicating the intake pipe 311 and the combustion chamber 201 and an exhaust port 222 for communicating the combustion chamber 201 and the exhaust pipe 321.

  The cylinder head 220 has an intake valve 223 for controlling the introduction of combustion air from the intake pipe 311 to the combustion chamber 201, and an exhaust valve for controlling the discharge of exhaust gas from the combustion chamber 201 to the exhaust pipe 321. An exhaust valve 224, an injector 225 for injecting fuel into the combustion chamber 201, and a spark plug 226 for igniting the air-fuel mixture in the combustion chamber 201 are attached.

  The injector 225 has a solenoid coil and a needle valve that are controlled by the ECU 100. Fuel is supplied to the injector 225 at a predetermined pressure. When the solenoid coil is energized by the ECU 100, the injector 225 opens the needle valve and injects fuel into the combustion chamber 201.

  The spark plug 226 is a known spark plug having an electrode made of platinum or an iridium alloy. The spark plug 226 is discharged when the electrode is energized by the ECU 100 and ignites the air-fuel mixture in the combustion chamber 201.

  As shown in FIG. 3, the engine 20 is provided with an intake camshaft 241 and an exhaust camshaft 242 rotatably above the cylinder head 220.

  The intake camshaft 241 is provided with an intake cam 243 that contacts the upper end of the intake valve 223. When the intake camshaft 241 rotates, the intake cam 243 opens and closes the intake valve 223 so that the intake port 221 and the combustion chamber 201 are opened and closed.

  The exhaust camshaft 242 is provided with an exhaust cam 244 that contacts the upper end of the exhaust valve 224. When the exhaust camshaft 242 rotates, the exhaust cam 244 opens and closes the exhaust valve 224 so that the combustion chamber 201 and the exhaust port 222 are opened and closed.

  An intake cam sprocket 245 and an intake side rotation phase controller 247 that rotates the intake camshaft 241 relative to the intake cam sprocket 245 are provided at one end of the intake camshaft 241.

  The intake side rotation phase controller 247 is controlled by the ECU 100 to rotate the intake camshaft 241 relative to the intake cam sprocket 245 so as to perform advance angle control and retard angle control.

  An exhaust cam sprocket 246 and an exhaust side rotation phase controller 248 that rotates the exhaust cam shaft 242 relative to the exhaust cam sprocket 246 are provided at one end of the exhaust cam shaft 242.

  The exhaust-side rotation phase controller 248 is controlled by the ECU 100 to rotate the exhaust camshaft 242 relative to the exhaust cam sprocket 246 so as to perform advance angle control and retard angle control.

  A crank sprocket 249 is provided at one end of the crankshaft 213. A timing belt 250 is wound around the intake cam sprocket 245, the exhaust cam sprocket 246 and the crank sprocket 249. The timing belt 250 transmits the rotation of the crank sprocket 249 to the intake cam sprocket 245 and the exhaust cam sprocket 246.

  Accordingly, the rotation of the crankshaft 213 is transmitted to the intake camshaft 241 and the exhaust camshaft 242 by the timing belt 250, so that the intake valve 223 and the exhaust valve 224 are driven by the intake camshaft 241 and the exhaust camshaft 242. However, the intake port 221 and the exhaust port 222 are opened and closed in synchronization with the crankshaft 213.

  The engine 20 is provided with a tensioner 251 that regulates the path of the timing belt 250. The tensioner 251 applies an appropriate tension to the timing belt 250 in order to prevent the timing belt 250 from being detached from the intake cam sprocket 245, the exhaust cam sprocket 246, and the crank sprocket 249.

  The crankshaft 213 is provided with a crank rotor 254 that rotates together with the crankshaft 213. The vehicle 10 includes a crank angle sensor 131 for detecting the rotation angle of the crank rotor 254.

  As shown in FIG. 4, the crank rotor 254 is provided with signal teeth on the outer periphery every 10 °, has one missing tooth portion for detecting top dead center, and has 34 tooth signal teeth on the entire circumference. Is provided.

  The crank angle sensor 131 is configured by an MRE sensor having a magnetic resistance element (MRE). When the crankshaft 213 rotates, the direction of the magnetic field applied to the crank angle sensor 131, that is, the magnetic vector changes due to the crests and valleys of the teeth provided on the crank rotor 254, and the internal resistance value changes.

  As shown in FIG. 5, the crank angle sensor 131 is shaped into a rectangular wave that takes a High state and a Low state by comparing the output waveform after converting the resistance value change into a voltage and a threshold value. A crank angle signal is generated, and the generated crank angle signal is output to the ECU 100.

  Further, the crank angle sensor 131 can detect the rotation angle of the crankshaft 213 every 10 ° by the crank rotor 254, and can detect the rotation position of the crankshaft 213 from the missing portion of the crank rotor 254. Be able to.

  In FIG. 3, a flywheel 258 that rotates together with the crankshaft 213 is provided at the other end of the crankshaft 213. The vehicle 10 includes a starter 259 for rotating the flywheel 258 when the engine 20 is started.

  The flywheel 258 is configured by a ring gear. The starter 259 has a motor that uses a battery as a power source and a pinion gear that is rotated by the motor.

  The starter 259 is controlled by the ECU 100 to rotate the crankshaft 213 by driving the motor by engaging the pinion gear with the flywheel 258 when the engine 20 is started, while the engine 20 is started. Is configured to separate the pinion gear from the flywheel 258 and stop the motor.

  The intake camshaft 241 and the exhaust camshaft 242 make one turn while the crankshaft 213 makes two turns. Therefore, with reference to the rotation angle of the crankshaft 213, the rotation angles of the intake camshaft 241 and the exhaust camshaft 242 will be described below using “CA” indicating the rotation angle of the crankshaft 213.

  The intake camshaft 241 is provided with an intake cam rotor 255 that rotates together with the intake camshaft 241. The exhaust camshaft 242 is provided with an exhaust cam rotor 256 that rotates together with the exhaust camshaft 242. The vehicle 10 includes an intake cam angle sensor 139 and an exhaust cam angle sensor 140 for detecting the rotation angles of the intake cam rotor 255 and the exhaust cam rotor 256, respectively. In the present invention, the intake cam angle sensor 139 and the exhaust cam angle sensor 140 are collectively referred to as a cam angle sensor.

  As shown in FIG. 6, the intake cam rotor 255 has peaks and valleys formed on the outer periphery. In intake cam rotor 255 in the present embodiment, a valley of 60 ° CA, a mountain of 180 ° CA, a valley of 180 ° CA, a mountain of 60 ° CA, a valley of 120 ° CA, and a mountain of 120 ° CA are formed in this order. Yes.

  The intake cam angle sensor 139 is configured in the same manner as the crank angle sensor 131. As shown in FIG. 7, when the intake cam shaft 241 rotates, the intake cam angle sensor 139 generates rectangular waves corresponding to peaks and valleys formed in the intake cam rotor 255. A cam angle signal of the shaft 241 (hereinafter referred to as “G2In signal”) is generated, and the generated G2In signal is output to the ECU 100.

  The exhaust cam rotor 256 is configured in the same manner as the intake cam angle sensor 139, and is provided on the exhaust cam shaft 242 in a state shifted by 60 ° CA compared to the intake cam rotor 255.

  The exhaust cam angle sensor 140 is configured in the same manner as the intake cam angle sensor 139, and when the exhaust cam shaft 242 rotates, a rectangular wave corresponding to peaks and valleys formed in the exhaust cam rotor 256 is converted into a cam angle signal of the exhaust cam shaft 242. (Hereinafter referred to as “G2Ex signal”), and the generated G2Ex signal is output to the ECU 100.

  As shown in FIG. 8, on the input side of the ECU 100, in addition to the crank angle sensor 131, the intake cam angle sensor 139, the exhaust cam angle sensor 140, and the throttle sensor 135, a start switch 134 for driving the starter 259, and others Various sensors are connected.

  On the other hand, devices to be controlled such as an injector 225, a spark plug 226, a starter 259, and a throttle valve actuator 314 are connected to the output side of the ECU 100.

  The ECU 100 is configured by a microcomputer including a CPU (Central Processing Unit), a ROM (Read Only Memory), a RAM (Random Access Memory), an EEPROM (Electrically Erasable and Programmable Read Only Memory), and an input / output interface circuit. As the CPU operates according to a program stored in the ROM in advance while using the temporary storage function of the RAM, the ECU 100 controls each part of the vehicle 10 in an integrated manner.

  Here, the configuration of ECU 100 that constitutes the control device for the internal combustion engine according to the embodiment of the present invention will be described.

  When the crank angle signal is not normally obtained from the crank angle sensor 131, the ECU 100 controls the engine 20 based on the cam angle signal, that is, the G2In signal or the G2Ex signal.

  In the present embodiment, the ECU 100 detects the rising edge of the cam angle signal at a constant sampling period Ts and detects the falling edge by interruption in order to reduce the processing load. Here, although the sampling period Ts is determined according to the processing speed of the ECU 100, it is set to 1 ms in the present embodiment. Specifically, the ECU 100 detects the rising edge of the G2In signal at a 1 ms period, and detects the falling edge of the G2In signal by interruption.

  The ECU 100 is configured to take one of a normal state and a fail-safe state. The ECU 100 always executes a diagnosis application that determines whether or not the crank angle signal output from the crank angle sensor 131 is normally obtained.

  For example, in the diagnosis application, when the number of edges of the crank angle signal detected between the edges of the G2In signal and the G2Ex signal is less than a predetermined number, or when the signal level of the crank angle signal deviates from a predetermined range. For example, it is determined that the crank angle signal is not normally obtained.

  When it is determined that the crank angle signal is normally obtained by the diagnosis application, the ECU 100 takes a normal state, and when it is determined that the crank angle signal is not normally obtained by the diagnosis application, It is designed to take a fail-safe state.

  Here, if the ECU 100 controls the intake-side rotation phase controller 247 and the exhaust-side rotation phase controller 248 in the fail-safe state, the relationship between the intake camshaft 241, the exhaust camshaft 242, and the crankshaft 213 changes. If cylinder discrimination is performed based on the cam angle signal, the accuracy of cylinder discrimination deteriorates.

  Therefore, when changing from the normal state to the fail-safe state, the ECU 100 controls the intake-side rotation phase controller 247 so that the intake camshaft 241 is at the reference position, that is, the intake-side rotation phase is at the most retarded angle. The exhaust-side rotation phase controller 248 is controlled so that the exhaust camshaft 242 reaches the reference position, that is, the exhaust-side rotation phase reaches the most advanced angle.

  In this case, it is preferable that the ECU 100 stops the cylinder discrimination until the control of the intake side rotational phase controller 247 and the exhaust side rotational phase controller 248 is completed. When the cylinder discrimination is stopped, the injector 225 and the spark plug 226 are not controlled by the ECU 100, and the fuel injection by the injector 225 and the ignition by the spark plug 226 are stopped, so that the combustion in the engine 20 stops.

  Here, the configuration of the ECU 100 will be described separately for a normal state and a fail-safe state.

(Normal state)
In the normal state, as shown in FIG. 9, the ECU 100 detects the three teeth of the crank angle signal output by the crank angle sensor 131 every 10 ° of the crankshaft 213, that is, when the crankshaft 213 rotates 30 °. A crank counter that counts one is generated.

  This crank counter counts from top dead center of the piston 211 to the next top dead center in a specific cylinder, for example, the cylinder (# 1) closest to the timing belt 250, as ccrnk0 to ccrnk23. Yes. The ECU 100 calculates the engine rotational speed Ne based on the count cycle of the crank counter.

  Further, the ECU 100 performs cylinder discrimination for measuring the control timing such as the ignition timing of the spark plug 226 and the fuel injection timing of the injector 225 for each cylinder based on the count value of the crank counter. In this way, the ECU 100 constitutes a cylinder discriminating unit that discriminates a cylinder in a normal state.

  In addition, the ECU 100 detects an edge corresponding to a crank angle at a constant interval among the rising and falling edges of the cam angle signal output from the cam angle sensors 139 and 140 that detect the rotation angles of the camshafts 241 and 242. Acquired as a valid edge.

  In the following description, the ECU 100 determines an edge corresponding to a crank angle at a constant interval among the rising edge and the falling edge of the G2In signal output from the intake cam angle sensor 139 that detects the rotation angle of the intake camshaft 241. It shall be acquired as a valid edge.

  The ECU 100 acquires the valid edges E1 to E4 for every 180 ° CA of the G2In signal output from the intake cam angle sensor 139. Note that the valid edges E1 to E4 of the G2In signal in the normal state are synchronized with the count values ccrnk2, 8, 14, and 20 of the crank counter, respectively. Thus, the ECU 100 constitutes an edge acquisition unit that acquires the edge of the cam angle signal in a normal state.

  In addition, the ECU 100 is configured to generate a cam counter that counts the acquired effective edges in preparation for a fail-safe state. In the present embodiment, the ECU 100 generates a cam counter (hereinafter referred to as “G2In counter”) that counts effective edges of the G2In signal. That is, in the normal state, the G2In counter repeatedly counts the count values ccam0, 1, 2, and 3 in synchronization with the count values ccrnk2, 8, 14, and 20 of the crank counter.

(Fail safe state)
As described above, the ECU 100 calculates the engine speed Ne based on the count value of the crank counter in the normal state, but in the fail-safe state, the ECU 100 calculates the engine speed Ne based on the effective edge of the G2In signal. Is calculated.

  The ECU 100 obtains fewer edges of the cam angle signal after the engine 20 is started than when the engine 20 is started. Thus, ECU100 comprises an edge acquisition means also in a fail safe state.

  In the present embodiment, the ECU 100 acquires all edges of the cam angle signal during the start of the engine 20, and after starting the engine 20, the 180 ° CA of the G2In signal output from the intake cam angle sensor 139. The effective edges E1 to E4 are acquired for each.

  Here, when the engine 20 is being started, the start switch 134 is on, the ECU 100 controls the starter 259, and the starter 259 rotates the flywheel 258, and then the rotation speed Ne of the engine 20 is predetermined. It refers to a period up to several Nth, for example, 250 rpm. Also, after the engine 20 is started, it means that the pinion gear of the starter 259 is separated from the flywheel 258 and the rotational speed Ne of the engine 20 is equal to or higher than a predetermined rotational speed Nth.

  The ECU 100 acquires all the edges of the G2In signal and the G2Ex signal during the start of the engine 20, and specifies the effective edge E1 corresponding to the count value ccrnk2 of the crank counter among the falling edges of the G2In signal. It has become.

  Here, the ECU 100 determines the falling edge of the G2In signal based on the ratio R1 between the High level period and the Low level period of the G2In signal and the edge interval dT between the falling edge of the G2In signal and the rising edge of the G2Ex signal. Among them, the effective edge E1 is specified.

  The ECU 100 can specify the effective edge E1 among the falling edges of the G2In signal based on only the ratio R1 or only the edge interval dT. However, in the present embodiment, the effective edge E1 is specified. In order to reliably specify the effective edge E1, the effective edge E1 is specified based on both the ratio R1 and the edge interval dT.

  First, as shown in FIGS. 10 to 12, the ratio R1 is a ratio TI (n−1) / the ratio of the previous Low level period TI (n−1) to the High level period TI (n) immediately before the G2In signal. Represents TI (n). The ECU 100 identifies the falling edge of the G2In signal that maximizes the ratio R1 as a candidate for the effective edge E1.

  That is, assuming that there is no fluctuation in the rotation of the engine 20, as shown in FIG. 10, the High level period TI (n) immediately before the G2In signal is approximately 60 ° CA with respect to the falling edge D1 of the G2In signal. Since the previous Low level period TI (n-1) is proportional to approximately 120 ° CA, the ratio R1 is approximately 2.

  Similarly, for the falling edge D3 of the G2In signal, as shown in FIG. 11, the High level period TI (n) immediately before the G2In signal is proportional to approximately 180 ° CA, and the preceding Low level period TI. Since (n−1) is proportional to approximately 180 ° CA, the ratio R1 is approximately 1.

  For the falling edge D4 of the G2In signal, as shown in FIG. 12, the High level period TI (n) immediately before the G2In signal is proportional to approximately 120 ° CA, and the preceding Low level period TI ( Since n-1) is proportional to approximately 60 ° CA, the ratio R1 is approximately 0.5.

  In this way, since the ratio R1 of the G2In signal to the falling edge D1 is maximized, the ECU 100 can specify the falling edge D1 of the G2In signal as a candidate for the effective edge E1.

  In addition, instead of specifying the falling edge of the G2In signal that maximizes the ratio R1 as a candidate for the effective edge E1, the ECU 100 validates the falling edge of the G2In signal in which the ratio R1 exceeds the predetermined ratio Rth1. You may make it identify as a candidate of edge E1. In this case, the ratio Rth1 is set to about 1.7, for example.

  On the other hand, as shown in FIGS. 13 to 14, the edge interval dT represents an overlapping period in which the High level period TI (n) immediately before the G2In signal and the High level period TE (n) immediately before the G2Ex signal overlap.

  The ECU 100 compares the ratio R2 = TI (n) / dT of the High level period TI (n) immediately before the G2In signal to the edge interval dT and the ratio R3 of the High level period TE (n) immediately before the G2Ex signal to the overlap period dT. = TE (n) / dT is calculated, and the falling edge of the G2In signal in which the calculated ratio R2 and ratio R3 are both maximum is specified as a candidate for the effective edge E1.

  That is, assuming that there is no fluctuation in the rotation of the engine 20, the overlapping period dT is proportional to approximately 0 ° CA with respect to the falling edge D1 of the G2In signal, as shown in FIG. Since the high level period TI (n) is proportional to approximately 60 ° CA and the high level period TE (n) immediately before the G2Ex signal is proportional to approximately 60 ° CA, both the ratio R2 and the ratio R3 are infinite. .

  For the falling edge D3 of the G2In signal, as shown in FIG. 14, the overlap period dT is proportional to approximately 120 ° CA, and the High level period TI (n) immediately before the G2In signal is approximately 180 ° CA. Since the High level period TE (n) immediately before the G2Ex signal is proportional to approximately 180 ° CA, the ratio R2 and the ratio R3 are both approximately 1.5.

  For the falling edge D4 of the G2In signal, as shown in FIG. 15, the overlap period dT is proportional to approximately 60 ° CA, and the High level period TI (n) immediately before the G2In signal is approximately 120 ° CA. Since the High level period TE (n) immediately before the G2Ex signal is proportional to approximately 120 ° CA, both the ratio R2 and the ratio R3 are approximately 2.

  Thus, since the ratios R2 and R3 with respect to the falling edge D1 of the G2In signal are both maximum, the ECU 100 can specify the falling edge D1 of the G2In signal as a candidate for the effective edge E1.

  In addition, instead of specifying the falling edge of the G2In signal in which the ratios R2 and R3 are both the maximum as the candidate for the effective edge E1, the ECU 100 specifies the G2In signal in which the ratios R2 and R3 both exceed the predetermined ratio Rth2. May be specified as a candidate for the effective edge E1. In this case, the ratio Rth2 is set to about 4.8, for example.

  When the falling edge of the G2In signal specified as a candidate for the effective edge E1 based on the ratio R1 matches the falling edge of the G2In signal specified as a candidate for the effective edge E1 based on the edge interval dT In addition, the falling edge of the G2In signal is specified as the effective edge E1.

  In FIG. 9, the ECU 100 predicts the acquisition timing of the next effective edge when acquiring the effective edge. Specifically, when the effective edge E2 is acquired, the ECU 100 predicts, as the acquisition timing of the next effective edge E3, the timing obtained by adding the time between the effective edges E1 to E2 from the acquisition timing of the effective edge E2. It has become.

  Similarly, when acquiring the effective edge E3, the ECU 100 predicts a timing obtained by adding the time between the effective edges E2 to E3 from the timing of acquiring the effective edge E3 as the acquisition timing of the next effective edge E4. ing.

  Further, when the ECU 100 acquires the effective edge E4, the ECU 100 predicts the timing obtained by adding the time between the effective edges E3 to E4 from the timing when the effective edge E4 is acquired as the acquisition timing of the next effective edge E1. Yes.

  Further, when the ECU 100 acquires the effective edge E1, the ECU 100 predicts, as the acquisition timing of the next effective edge E2, a timing obtained by adding the time between the effective edges E4 to E1 from the timing at which the effective edge E1 is acquired. Yes.

  The ECU 100 is configured to count the rotation angle of the crankshaft 213 in a pseudo manner by multiplying the acquired effective edge acquisition timing by the predicted acquisition timing of the next effective edge. Specifically, the ECU 100 generates a fail-safe crank counter (hereinafter simply referred to as “F / S crank counter”). In this way, the ECU 100 constitutes a pseudo counting unit in the fail safe state.

  Here, the initial value of the crank counter for F / S generated during the start of the engine 20 is the valid edge specified as the valid edge corresponding to the count value ccrnk2 of the crank counter among the falling edges of the G2In signal. Set to ccrnk2 when E1 is acquired.

  Note that the ECU 100 specifies the valid edge E1 during the start of the engine 20, and then uses the F / S signal so that all edges of the G2In signal and the G2Ex signal are synchronized with the corresponding count values of the F / S crank counter, respectively. The count value of the crank counter may be adjusted.

  On the other hand, the initial value of the F / S crank counter generated after the engine is started is determined based on the count value of the G2In counter. That is, after determining that the crank angle signal is not normally obtained by the diagnosis application and completing control by the ECU 100 for the intake side rotational phase controller 247 and the exhaust side rotational phase controller 248, the count value of the G2In counter becomes ccam0. The initial value of the F / S crank counter is set to ccrnk2, and when the count value of the G2In counter becomes ccam1, the initial value of the F / S crank counter is set to ccrnk8. When the count value becomes ccam2, the initial value of the F / S crank counter is set to ccrnk14, and when the count value of the G2In counter becomes ccam3, the initial value of the F / S crank counter is set to ccrnk20. Set

  In the present embodiment, when the ECU 100 acquires the effective edge of the G2In signal, the ECU 100 multiplies between the acquisition timing of the acquired effective edge and the predicted acquisition timing of the next effective edge by 6 times, thereby obtaining the F / S. The count value (count value) is adjusted so that the count value ccrnk2, 8, 14, 20 of the crank counter for F / S is synchronized with each valid edge of the G2In signal. It is supposed to be.

  In addition, the ECU 100 performs the cylinder discrimination based on the count value of the crank counter in the normal state, but performs the cylinder discrimination based on the count value of the F / S crank counter in the fail-safe state. It has become. Thus, the ECU 100 constitutes a cylinder discrimination unit even in the fail-safe state.

  Next, the operation of ECU 100 that constitutes the control device for an internal combustion engine according to the embodiment of the present invention will be described.

  FIG. 16 is a flowchart for explaining the cylinder discrimination operation in the fail-safe state by the ECU 100.

  First, the ECU 100 determines whether or not the engine 20 is being started (step S1). If it is determined that the engine 20 is starting, the ECU 100 adjusts the count value of the F / S crank counter based on all the edges of the G2In signal and the G2Ex signal (step S2).

  On the other hand, when it is determined that the engine 20 is not being started, that is, the engine 20 is after being started, the ECU 100 adjusts the count value of the F / S crank counter based on the effective edge of the G2In signal (step S1). S3).

  Then, the ECU 100 performs cylinder discrimination based on the adjusted count value of the F / S crank counter (step S4).

  As described above, the control apparatus for an internal combustion engine according to the present embodiment performs cylinder discrimination by acquiring more cam angle signal edges during the start of the engine 20 than after the engine 20 has started. Accurate cylinder discrimination can be performed, and the time required to start the engine 20 can be shortened.

  On the other hand, since the control device for the internal combustion engine according to the present embodiment performs cylinder discrimination after acquiring the cam angle signal edge less than when the engine 20 is started, the load on the ECU 100 is increased. Can be reduced.

  Therefore, the control device for an internal combustion engine according to the present embodiment conventionally applies a load on ECU 100 that performs cylinder discrimination even when cylinder discrimination is performed based only on the cam angle signal output from the cam angle sensor. While the engine 20 is being started, the cylinder discrimination can be performed with high accuracy during the start of the engine 20, and the time required for starting the engine 20 can be shortened.

  Further, the control device for the internal combustion engine according to the present embodiment improves the accuracy of cylinder discrimination by acquiring all the edges of the cam angle signal during the start of the engine 20, and after the start of the engine 20, By acquiring only the effective edges necessary for pseudo-counting the rotation angle of the crankshaft 213, the load on the ECU 100 that executes cylinder discrimination can be reduced as compared with the conventional one.

  Further, the internal combustion engine control apparatus according to the present embodiment includes three rising edges of the G2In signal of the cam angle signal and three rising edges of the G2Ex signal during 720 ° CA during the start of the engine 20. However, after the engine 20 is started, in order to acquire one rising edge of the G2In signal of the cam angle signal during 720 ° CA, in particular, the ECU 100 detects the rising edge of the cam angle signal at a constant sampling period Ts. In the case where the falling edge is detected by interruption, the load on the ECU 100 can be greatly reduced.

  In the present embodiment, an example in which the crank angle sensor 131 is configured by an MRE sensor has been described. However, in the present invention, the crank angle sensor 131 has a known electromagnetic pickup coil (MPU). You may be comprised by the MPU sensor which has, and the waveform shaping circuit which shapes an alternating current into a rectangular wave.

  Further, in the present embodiment, as shown in FIG. 6, the intake cam rotor 255 has a 60 ° CA valley, a 180 ° CA mountain, a 180 ° CA valley, a 60 ° CA mountain, and a 120 ° CA mountain in order. In the present invention, the intake cam rotor 255 has a plurality of peaks having different lengths and a plurality of valleys having different lengths formed on the outer periphery. The shape shown in FIG. 6 is not necessary as long as an effective edge that equally divides 720 ° CA is obtained.

  Further, in the present embodiment, the ECU 100 determines G2In based on the ratio R1 between the High level period and Low level period of the G2In signal and the edge interval dT between the falling edge of the G2In signal and the rising edge of the G2Ex signal. In the present invention, the ECU 100 validates the falling edge of the G2In signal identified as a candidate for the valid edge E1 based only on the ratio R1. It may be specified as the edge E1. In this case, the ECU 100 may acquire all edges of the G2In signal while the engine 20 is starting.

  In the present invention, the ECU 100 also identifies the falling edge of the G2In signal identified as a candidate for the effective edge E1 based only on the edge interval dT between the falling edge of the G2In signal and the rising edge of the G2Ex signal as the effective edge E1. You may make it do.

  Further, in the present invention, by changing the installation angle of the intake cam rotor 255 with respect to the intake camshaft 241 and the installation angle of the exhaust cam rotor 256 with respect to the exhaust camshaft 242, for example, as shown in FIG. The engine 20 can be controlled by replacing the signal and the G2Ex signal.

  That is, the ECU 100 adjusts the count value of the F / S crank counter based on the effective edge of the G2Ex signal instead of adjusting the count value of the F / S crank counter based on the effective edge of the G2In signal. You may do it.

  In this case, in a normal state, the ECU 100 is configured to acquire an edge corresponding to a crank angle at a constant interval as an effective edge among the rising edge and the falling edge of the G2Ex signal. In the fail-safe state, the ECU 100 is configured to acquire effective edges E1 to E4 for every 180 ° CA of the G2Ex signal output from the exhaust cam angle sensor 140 after the engine 20 is started.

  In the fail-safe state, the ECU 100 acquires all edges of the G2Ex signal and the G2In signal during the start of the engine 20, and corresponds to the count value ccrnk2 of the crank counter in the falling edge of the G2Ex signal. The effective edge E1 is configured to be specified.

  Here, the ECU 100 determines whether the falling edge of the G2Ex signal is based on the ratio between the High level period and the Low level period of the G2Ex signal and the edge interval between the falling edge of the G2Ex signal and the rising edge of the G2In signal. Thus, the effective edge E1 is specified.

  Note that the ECU 100 may specify the falling edge of the G2Ex signal specified as a candidate for the effective edge E1 based on the ratio between the High level period and the Low level period of the G2Ex signal as the effective edge E1. In this case, the ECU 100 may acquire all edges of the G2Ex signal while the engine 20 is starting.

  Further, in the present invention, the ECU 100 specifies the falling edge of the G2Ex signal specified as a candidate for the effective edge E1 based on the edge interval between the falling edge of the G2Ex signal and the rising edge of the G2In signal as the effective edge E1. It may be.

  Thus, by changing the shape of the intake cam rotor 255 and the exhaust cam rotor 256, the installation angle of the intake cam rotor 255 with respect to the intake cam shaft 241, and the installation angle of the exhaust cam rotor 256 with respect to the exhaust cam shaft 242, the ECU 100 can fail. If the edge of the cam angle signal corresponding to the specific count value of the crank counter can be specified during the start of the engine 20 in the safe state, all the rising edges of the G2In signal and the G2Ex signal may be acquired. Alternatively, all the falling edges of the G2In signal and the G2Ex signal may be acquired.

  As described above, the control device for an internal combustion engine according to the present invention loads the ECU on which cylinder discrimination is performed even when cylinder discrimination is performed based only on the cam angle signal output from the cam angle sensor. While the internal combustion engine is being started, the cylinder can be discriminated with high accuracy and the time required for starting the internal combustion engine can be shortened. Useful for general engine control devices.

10 vehicle 20 engine 21 cylinder 100 ECU (edge acquisition means, pseudo-counting means, cylinder discrimination means)
131 Crank angle sensor 139 Intake cam angle sensor 140 Exhaust cam angle sensor 201 Combustion chamber 211 Piston 213 Crankshaft 221 Intake port 222 Exhaust port 223 Intake valve 224 Exhaust valve 225 Injector 226 Spark plug 230 Oil pan 241 Intake camshaft 242 Exhaust camshaft 243 Intake cam 244 Exhaust cam 254 Crank rotor 255 Intake cam rotor 256 Exhaust cam rotor 258 Flywheel 311 Intake pipe 321 Exhaust pipe

Claims (8)

A crank angle sensor that detects a rotation angle of the crankshaft and generates a crank angle signal, and a cam angle sensor that detects a rotation angle of the camshaft and generates a cam angle signal are provided from the crank angle sensor. In the control device for an internal combustion engine that controls the internal combustion engine based on the cam angle signal when the angle signal cannot be obtained normally,
Edge acquisition means for acquiring an edge of the cam angle signal;
Pseudo-counting means for pseudo-counting the rotation angle of the crankshaft based on the edge acquired by the edge acquiring means;
Cylinder discrimination means for performing cylinder discrimination based on the count value of the pseudo-counting means,
The control device for an internal combustion engine, wherein the edge acquisition means acquires less edges among the edges of the cam angle signal after the internal combustion engine is started than during startup of the internal combustion engine.   The control apparatus for an internal combustion engine according to claim 1, wherein the edge acquisition unit acquires all edges of the cam angle signal during startup of the internal combustion engine.   The edge acquisition means acquires an effective edge of the cam angle signal corresponding to a crank angle at a constant interval among all the edges of the cam angle signal after the internal combustion engine is started. The control apparatus for an internal combustion engine according to claim 2. The cam angle sensor detects the rotation angle of the intake camshaft and generates an intake cam angle signal, and the exhaust cam angle sensor detects the rotation angle of the exhaust camshaft and generates an exhaust cam angle signal. Including
2. The control device for an internal combustion engine according to claim 1, wherein the edge acquisition means acquires all edges of the intake cam angle signal and the exhaust cam angle signal while the internal combustion engine is started. . The cam angle sensor includes an intake cam angle sensor that detects a rotation angle of an intake cam shaft and generates an intake cam angle signal;
2. The control apparatus for an internal combustion engine according to claim 1, wherein the edge acquisition means acquires all edges of the intake cam angle signal during startup of the internal combustion engine. The cam angle sensor includes an exhaust cam angle sensor that generates an exhaust cam angle signal by detecting a rotation angle of the exhaust cam shaft,
2. The control apparatus for an internal combustion engine according to claim 1, wherein the edge acquisition means acquires all edges of the exhaust cam angle signal during startup of the internal combustion engine.   The edge acquisition means acquires an effective edge of the intake cam angle signal respectively corresponding to a crank angle at regular intervals among all the edges of the intake cam angle signal after the internal combustion engine is started. The control device for an internal combustion engine according to claim 4 or 5.   The edge acquisition means acquires an effective edge of the exhaust cam angle signal corresponding to a crank angle at a constant interval among all edges of the exhaust cam angle signal after the internal combustion engine is started. The control apparatus for an internal combustion engine according to claim 4 or 6.

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