JP2013167223A - 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 allowing normal operation to be continued even in a failure of a crank angle signal.SOLUTION: When a crank angle sensor is normally activated and stable idle operation is carried out, an ECU stores an angular difference between a predetermined cam angle and a predetermined crank angle as a learning value without carrying out fail safe to the crank angle sensor. In addition, when determining that the crank angle sensor is not normally activated (YES in a step S11), the ECU carries out control processing of an engine to carry out the fail safe to the crank angle sensor (step S12). Meanwhile, when determining that the crank angle sensor is normally activated (NO in the step S11), the ECU terminates the control processing of the engine without carrying out the fail safe.

Description

  The present invention relates to a control device for an internal combustion engine that controls ignition timing of a spark plug and fuel injection timing of an injector.

  In general, an internal combustion engine includes a crankshaft as an output shaft, a timing belt wound around a crank sprocket that rotates coaxially with the crankshaft, a camshaft driven via the timing belt, and a camshaft. A cam mechanism that is driven and an intake / exhaust valve that is opened and closed by the cam mechanism are provided. The timing belt and the cam mechanism are configured so that the vertical movement of the piston and the opening / closing of the intake / exhaust valve can be continuously operated at appropriate timing. A crank angle sensor disposed in the vicinity of the crankshaft detects the rotation angle of the crankshaft and outputs a crank angle signal. A vehicle equipped with such an engine includes an engine control device. This control device optimally controls the control timing such as the ignition timing of the spark plug and the fuel injection timing of the injector based on the input crank angle signal.

  As such a control device for an internal combustion engine, one having a fail-safe function for avoiding a situation such as an engine stall even when a crank angle signal cannot be normally obtained due to a failure of a crank angle sensor or the like is known. (For example, see Patent Documents 1 and 2).

  In the control apparatus for an internal combustion engine disclosed in Patent Document 1, the pseudo start timing is generated at the output timing of the cam angle signal when the crank angle sensor is abnormal. In this control device, a time interval obtained by equally dividing the time interval of the output timing of the cam angle signal that has already been output into a plurality of portions in the period from when the cam angle signal is output to immediately before the next cam angle signal is output It is set as a pseudo start timing.

  Moreover, in the conventional control device described in Patent Document 2, the time required for outputting a predetermined number of crank angle signals is measured as a predetermined crank angle time, and compared with the previous crank angle time, The abnormality of the crank angle sensor is quickly detected by determining whether or not the crank angle sensor is abnormal depending on whether or not the crank time fluctuates more than a predetermined value.

JP 2011-208509 A JP 2011-069282 A

  However, in the conventional control device described in Patent Document 1 as described above, control that assumes that an angular difference occurs in the relative positional relationship between the crank angle and the cam angle is not executed. The fail-safe effect to cope with the abnormal crank angle sensor was uncertain. That is, when the crank angle signal cannot be obtained normally due to a failure of the crank angle sensor or the like in a state where this angle difference is occurring, the combustion state in the internal combustion engine becomes a desired state such as pre-ignition or knocking. There was a possibility of engine stall. For this reason, in a vehicle equipped with the internal combustion engine, if an abnormality occurs in the crank angle sensor, the vehicle may not be able to travel to a repair shop on its own, and the catalyst for detoxifying exhaust gas may be caused by high-temperature exhaust gas. There was a possibility of hurting.

  Moreover, even in the conventional control device described in Patent Document 2, the fail-safe effect is uncertain. That is, similar to the one described in Patent Document 1, when the crank angle sensor fails, control that assumes that there is an angle difference in the relative positional relationship between the crank angle and the cam angle is not executed. There was a possibility.

  Furthermore, the relative positional relationship between the crank angle and the cam angle may be unavoidable during manufacturing due to manufacturing variations, and may be shifted due to aging. Due to the angle difference due to the deviation, an error may occur in the timing when the control device generates the pseudo crank angle signal based on the cam angle signal output from the cam angle sensor. As described above, when there is an angle difference in the relative positional relationship between the crank angle and the cam angle, when the crank angle signal cannot be normally obtained due to a failure of the crank angle sensor or the like, the combustion state such as occurrence of engine stall is desired. There was a possibility that it was not in a state.

  The present invention has been made to solve such a problem, and more reliably provides fail-safe when the crank angle signal fails. Even when the output of the crank angle detecting means is not normal, pre-ignition and knocking are prevented. An object of the present invention is to provide a control device for an internal combustion engine that can avoid occurrence, stabilize the combustion state in the internal combustion engine, and enable normal operation.

  In order to achieve the above object, a vehicle control apparatus according to the present invention includes (1) a crank angle detection means for detecting a crank angle signal representing a crank angle of a crankshaft of an internal combustion engine, and a cam angle of a camshaft of the internal combustion engine. In the control apparatus for an internal combustion engine, comprising: a cam angle detection means for outputting a cam angle signal representing the control signal; and a control means for controlling an output of the internal combustion engine based on the crank angle signal and the cam angle signal. A determination means for determining whether or not the detection result of the angle detection means is normal; and when the determination result of the determination means is normal, the angle difference between the crank angle and the cam angle is determined as the crank angle signal and the cam Angle difference calculating means for calculating based on an angle signal, storage means for storing the angle difference calculated by the angle difference calculating means as a learning value, cam angle signal, and learning stored in the storage means Pseudo crank angle signal generating means for generating a pseudo crank angle signal based on the value, and when the determination result of the determination means is normal, the control means stores the learning value in the storage means When the determination result is not normal, the internal combustion engine is controlled based on the pseudo crank angle signal.

  With this configuration, when the determination unit determines that the operation is normal based on the crank angle signal output from the crank angle detection unit, the control unit stores the difference between the crank angle and the cam angle as a learning value in the storage unit. In addition, if the crank angle signal is not normal, the control means can generate the pseudo crank angle signal based on the cam angle signal output from the cam angle detection means and the learning value stored in the storage means. Therefore, even when the crank angle signal is not normal, the internal combustion engine can be controlled in the same manner as when the crank angle signal is normally output. As a result, even when the output of the crank angle detection means is not normal, the angle difference between the crank angle and the cam angle is reflected in the fail safe control as a learning value, so that the combustion state in the internal combustion engine is stabilized and normal operation is possible. can do.

  Further, in the control device for an internal combustion engine according to (1), (2) the pseudo crank angle signal generating means is based on a timing obtained by equally dividing a time interval of a predetermined output timing of the cam angle signal. Generating the pseudo crank angle signal.

  With this configuration, the number of pulses of the crank angle signal generated by the pseudo crank angle signal generating means is increased to an integral multiple of the frequency of the cam angle signal generated as the camshaft rotates. Corresponding to the increased frequency, the control accuracy with respect to the rotation angle is increased.

  In the control device for an internal combustion engine according to (1) or (2), (3) the determination means determines whether the detection result of the crank angle detection means is normal based on the waveform of the crank angle signal. It is characterized by determining.

  With this configuration, the determination unit can accurately determine whether or not the detection result of the crank angle detection unit is normal based on the waveform of the crank angle signal, so that the determination accuracy can be improved.

  According to the present invention, fail safe at the time of failure of the crank angle signal is ensured, and even when the output of the crank angle detection means is not normal, the occurrence of pre-ignition and knocking is avoided, and the combustion state in the internal combustion engine is reduced. It is possible to provide a control device for an internal combustion engine that can be stabilized and can be operated normally.

1 is a 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. 1 is a schematic cross-sectional view of an engine according to an embodiment of the present invention. 1 is a schematic perspective view of an engine according to an embodiment of the present invention. It is a side view of the crank rotor provided in the crankshaft of the engine which concerns on one embodiment of this invention. It is a graph which shows the crank angle signal which the crank angle sensor provided in the engine which concerns on one embodiment of this invention outputs. It is a side view of the intake cam rotor provided in the intake camshaft of the engine which concerns on one embodiment of this invention. It is a graph which shows the cam angle signal which the intake cam angle sensor provided in the engine which concerns on one embodiment of this invention outputs. 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 between a crank angle signal, a cam angle signal, and a crank counter in an ECU constituting the control device for an internal combustion engine according to the embodiment of the present invention. It is a flowchart for demonstrating the process of learning the angle difference for fail safe in ECU which comprises the control apparatus of the internal combustion engine which concerns on one embodiment of this invention. It is a flowchart for demonstrating the control action of the internal combustion engine in the fail safe state in ECU which comprises the control apparatus of the internal combustion engine which concerns on one embodiment of this invention.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings.

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

  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 engine are used. Alternatively, it may be constituted by various types of engines such as 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 configured 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. It will be explained as a thing.

  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.

  As will be described later, a deviation in the relative position of the cam angle with respect to the crank angle may occur due to variations in manufacturing, deterioration over time, and the like. The deviation of the relative position is a deviation from the design center and means an angle difference according to the present invention. This angle difference causes various harmful effects. Therefore, the ECU 100 performs the advance angle control or the retard angle control so as to cancel out the angle difference, and maintains the timing setting at the center of the design so that the original performance of the engine 20 is exhibited.

  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. The crank angle sensor 131 according to the present embodiment forms a crank angle detection unit according to the present invention.

  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 converts the resistance value change into a voltage and outputs a rectangular wave that alternately becomes a high state and a low state by comparing a waveform output with a threshold value. A shaped crank angle signal is generated, and the generated crank angle signal is output to the ECU 100.

  In addition, 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 at the part where the crank rotor 254 is missing. It is like that. Note that the missing portion corresponds to the position of the crank angle signal low state indicated by the solid line 62 in FIG.

  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 (not shown) for rotating the flywheel 258 when the engine 20 is started.

  The flywheel 258 is configured by a ring gear. The starter has a motor that uses a battery as a power source and a pinion gear that is rotated by the motor. The starter rotates the crankshaft 213 by engaging the pinion gear with the flywheel 258 and driving the motor when the engine 20 is started, while rotating the crankshaft 213 after the engine 20 is started. It is separated and the motor is stopped.

  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. In the following description, when it is not necessary to distinguish between the intake camshaft 241 and the exhaust camshaft 242, the camshaft 232 will be described.

  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. Note that the intake cam angle sensor 139 and the exhaust cam angle sensor 140 according to the present embodiment constitute cam angle detection means according to the present invention. In the following description, when it is not necessary to distinguish between the intake cam angle sensor 139 and the exhaust cam angle sensor 140, the cam angle sensor 130 will be described.

  Here, the necessity of obtaining the crank angle signal and the cam angle signal from both the crank angle sensor 131 and the cam angle sensor 130 will be described. As described above, in the 4-cycle engine, the camshaft 232 rotates once while the crankshaft 213 rotates twice. For example, when only the crank angle signal is used, it is not possible to know which cylinder is in the compression stroke or the exhaust stroke when the piston is moving up. Therefore, it is necessary to discriminate it from the cam angle signal. This is called cylinder discrimination.

  Also, the crank angle has a higher resolution than the cam angle, and the cam angle signal is affected by the timing belt 250, so that the crank angle signal is more accurate in controlling the timing. Therefore, the ECU 100 obtains information on the crank angle signal and the cam angle signal having different properties from both the crank angle sensor 131 and the cam angle sensor 130, and calculates the ignition timing, the fuel injection timing, and the injection amount. .

  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. The cam angle signal is generated as a cam angle signal of the shaft 241, and the generated cam angle 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. And the generated cam angle 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, and other various types The sensor is connected.

  On the other hand, devices to be controlled such as an injector 225, a spark plug 226, 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) 100a, a ROM (Read Only Memory) 100b, a RAM (Random Access Memory) 100c, a backup memory 100d, and an input / output interface circuit. The CPU 100a performs arithmetic processing according to a program stored in the ROM 100b in advance while using the temporary storage function of the RAM 100c, so that the ECU 100 controls each part of the vehicle 10 in an integrated manner. Further, the ECU 100 according to the present embodiment constitutes storage means according to the present invention.

  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.

  The ECU 100 discriminates the cylinder based on the pulse signals corresponding to the rotation of the crankshaft 213 and the camshaft 232, that is, the crank angle signal and the cam angle signal, and calculates the ignition timing, the fuel injection timing, and the injection amount.

  The ECU 100 controls the engine 20 based on the cam angle signal when the crank angle signal is not normally obtained from the crank angle sensor 131.

  The ECU 100 determines whether the crank angle signal is in a normal state where the crank angle signal is normally obtained or a fail-safe state where the crank angle signal is not normally obtained, and responds to each state. Control is to be executed. 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 a diagnosis application, when the cam angle signal or the number of crank angle signals detected between each edge of the cam angle signal is less than a predetermined number, the signal level of the crank angle signal is out of the predetermined range. It is determined that the crank angle signal is not obtained normally, for example, when it is different from the predetermined pulse waveform.

  When it is determined that the crank angle signal is normally obtained by the diagnosis application, the ECU 100 recognizes that the crank angle signal is normally obtained and determines that the crank angle signal is not normally obtained by the diagnosis application. In such a case, it is recognized that the state is a fail-safe state, and control according to the fail-safe state is executed. The diagnosis application and the ECU 100 according to the present embodiment constitute a determination unit according to the present invention.

  Next, 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, the ECU 100 generates a crank counter 72 as shown in FIG. That is, when the crankshaft 213 is output by the crank angle sensor 131, the crankshaft 213 is incremented by three teeth of the crank angle signal every 10 °, that is, when the crankshaft 213 rotates 30 °, and the voltage increases stepwise. The voltage is reset to the low state every cycle 720 °. In FIG. 9, the timing 62 in the crank angle signal low state corresponds to the timing at which the crank angle sensor 131 detects the missing teeth of the crank rotor 254.

  The crank counter 72 counts from the top dead center of the piston 211 to the next top dead center in a specific cylinder, for example, a cylinder (not shown) closest to the timing belt 250.

  The ECU 100 calculates the engine speed based on the count cycle of the crank counter 72. Further, the ECU 100 defines control timings 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 72.

  Further, the ECU 100 is in a low state corresponding to the missing tooth 62 in the crank angle signal 61 out of the rising edge D1 and the falling edge D2 of the cam angle signal output from the cam angle sensor 130 that detects the rotation angle of the camshaft 232. The D2 edge corresponding to the falling edge D2 of one pulse that occurs first immediately after the end of the process is detected. Hereinafter, the falling edge D2 is also referred to as a predetermined timing D2.

  In addition, the ECU 100 is configured to generate a cam angle counter that counts the edge of the cam angle signal in preparation for a fail-safe state. In the normal state, the cam angle counter repeatedly counts the count value in synchronization with not only the cam angle signal but also the crank angle signal, that is, the count value of the crank counter 72.

(Fail safe state)
In the fail-safe state, the ECU 100 detects the edge of the cam angle signal and executes the fail-safe control as in the normal state, that is, the optimal state for controlling the engine 20, that is, the cam angle. It is designed to maintain the same state as when the signal is at the design center.

  For example, the ECU 100 calculates the rotational speed of the camshaft 232 based on the rising edge D1 and the predetermined timing D2 of the design center cam angle signal 63 shown in FIG. 9, and generates a 60 ° CA signal. The timing of this 60 ° CA signal is the timing of the learning value zero shown in FIG. Further, when the cam angle signal causes the delay angle deviation or the advance angle deviation shown in FIG. 9, the ECU 100 executes a calculation process described later, and uses the learning value for the timing of the cam angle signal to set the timing. By correcting, a pseudo crank angle signal is generated.

  Here, the learning value is an angle difference that should be corrected by the control of the ECU 100. In addition, as described above, the angle difference is caused by the relative position of the predetermined cam angle with respect to the predetermined crank angle deviating from the design center due to variations in manufacturing and aging deterioration. This angular difference causes a decrease in the accuracy of various controls. Therefore, the ECU 100 stores the angle difference as a learned value when a predetermined condition is satisfied in the normal state, and when the ECU 100 shifts to the fail-safe state, the ECU 100 calculates the angle difference represented by the learned value. It is used to correct the timing of the crank counter. The timing correction amount for the cam angle signal is obtained by dividing the angle difference represented by the learning value by the rotational speed of the cam shaft 232.

  In FIG. 9, a solid line 70 is a cam angle signal with a delay shift with respect to the cam angle signal 63 at the design center. A solid line 69 is a cam angle signal accompanied by an advance angle shift with respect to the cam angle signal 63 at the design center. The falling edge D3 is a timing of the delay angle shift with respect to the predetermined timing D2, and is also referred to as a delay angle shift timing D3. Conversely, the falling edge D4 is the timing of the advance angle deviation with respect to the predetermined timing D2, and is also referred to as the advance angle deviation timing D4.

  The crank counter 71 is a crank counter value that is generated when the ECU 100 learns the advance deviation angle and does not perform correction according to the learned value. That is, this is the crank counter value before the ECU 100 reflects the learned value in the fail safe control. When the correction by the learning value is not performed, the ECU 100 forms the first tooth of the crank counter by detecting the rising edge D5. Therefore, the crank counter 71 is shifted from the crank counter 72 by the predetermined timing D2. An advance angle shift corresponding to the difference from the timing D4 occurs. The deviation according to the present embodiment represents a value corresponding to the angle difference according to the present invention.

  On the other hand, when correction according to the learning value is performed, even if the rising edge D5 is detected, the ECU 100 forms the first tooth of the crank counter at a timing delayed by the learning value from this detection. ing. The crank counter 72 generated in this way matches the waveform in which the voltage rises stepwise from the time of the rising edge D1 when there is no delay angle shift or advance angle shift.

  Note that the time for one step of the crank counter 72 is set to ½ of the time of the signal high state from the rising edge D1 to the predetermined timing D2, that is, the time required for rotation of 60 ° CA. . Therefore, after resetting at the timing of the rising edge D1, the crank counter 72 is reset every time it rotates 720 ° CA / 2 by increasing the voltage in 24 steps in steps of 30 ° CA in the same manner as the normal state described above. Is done.

  Therefore, the ECU 100 can execute the control of the engine 20 in a state where the influence due to the occurrence of the angle difference is suppressed by using the pseudo crank angle signal based on the crank counter 72 in which the learned value is reflected. Therefore, the engine 20 can be fail-safe controlled with more accurate timing. As a result, it is possible to eliminate a reduction in accuracy of various controls caused by an angle difference that occurs when the relative position of the predetermined cam angle with respect to the predetermined crank angle deviates from the design center due to variations in manufacturing, aging deterioration, and the like.

  Next, the operation of the control process of the engine 20 in the present embodiment will be described with reference to the flowcharts shown in FIGS. FIG. 10 is a flowchart showing the operation of a control process for learning the deviation of the relative positional relationship (timing) between the crank angle and the cam angle during normal operation. FIG. 11 is a flowchart showing an operation of a control process for generating a pseudo crank angle signal when the crank angle sensor 131 is not normal.

  The flowchart shown in FIG. 10 represents the execution contents of the program for the control process of the engine 20 executed by the ECU 100 using the RAM 100c as a work area. A program for controlling the engine 20 is stored in the ROM 100b of the ECU 100. In addition, the control process of the engine 20 is executed by the ECU 100 at predetermined time intervals from when the ignition is turned on to when it is turned off. For example, it is executed once in an hour with the ignition turned on, or at a preset time interval such as a day about 1 month after the previous execution in conjunction with the calendar.

  As shown in FIG. 10, first, the ECU 100 determines whether or not an abnormality has occurred in the crank angle sensor 131 (step S1). Specifically, the ECU 100 determines whether or not the signal waveform of the crank angle sensor 131 is an abnormal waveform as described above.

When it is determined that the crank angle sensor 131 is not abnormal, that is, the crank angle sensor 131 is operating normally (YES in step S1), the ECU 100 determines whether or not a stable idle operation is being performed ( Step S2). In this step, for example, the ECU 100 determines whether or not the fluctuation of the engine speed is within a predetermined range based on the waveform obtained in step S1, and whether or not an accelerator pedal (not shown) is depressed. Determine. When ECU 100 determines that the engine speed fluctuation is within a predetermined range, the accelerator pedal is not depressed, and the engine is in stable idle operation (determined as YES in step S2), crank angle Without performing fail-safe for the sensor 131, the angle difference is stored as a learning value as shown in the following formula (1). That is, the angle difference between the predetermined cam angle and the predetermined crank angle is stored as a learning value (step S3).
Learning value = Predetermined cam angle-Predetermined crank angle (1)

  Specifically, ECU 100 performs arithmetic processing based on the cam angle signals output from intake cam angle sensor 139 and exhaust cam angle sensor 140 and the crank angle signal output from crank angle sensor 131, and uses the angle difference as a learning value. Store in the RAM 100c.

  Note that if the ECU 100 determines that the crank angle sensor is not normal (NO in step S1) or determines that it is not a stable idle operation (NO in step S2), the ECU 100 returns to the routine without updating the learning value. Transition.

  On the other hand, the ECU 100 determines whether or not the crank angle sensor 131 is abnormal as shown in FIG. 11 in order to determine whether or not it is necessary to execute fail-safe (step S11). Specifically, the ECU 100 determines whether or not the signal waveform of the crank angle sensor 131 is a waveform representing the above-described abnormality.

  When ECU 100 determines that crank angle sensor 131 is abnormal, that is, crank angle sensor 131 is not operating normally (YES in step S11), ECU 100 performs fail-safe for crank angle sensor 131. Then, the pseudo crank angle signal is generated, and the control process of the engine 20 is executed (step S12).

Specifically, the ECU 100 controls the engine 20 based on the pseudo crank angle signal generated based on the learning value stored in the RAM 100c. That is, the ECU 100 performs arithmetic processing as shown in the following formula (2).
Estimated crank position = Crank angle temporarily set by cam angle signal + Learning value (2)

  In the present embodiment, the crank angle is provisionally set to 60 ° CA. As described with reference to FIG. 9, the ECU 100 calculates the rotational speed based on the rising edge D5 and the falling edge D4 of the cam angle signal (solid line 69) including the advance angle deviation, and generates a 60 ° CA signal. The ECU 100 generates a crank counter using an electronic circuit (not shown) based on the 60 ° CA signal. At this time, the ECU 100 reflects the timing error obtained from the learning value obtained by the calculation process and the rotational speed of the camshaft 232 in the rising edge D5, and sets the time interval between the rising edge D5 and the falling edge D4 to 2 By using the equally divided timing, a crank counter 72 that increases the voltage every 30 ° CA is generated.

  In this way, even when the crank angle signal fails, that is, when the output of the crank angle sensor 131 is not normal, the ECU 100 generates the pseudo crank angle signal from the output of the cam angle sensor 130, and the conventional crank angle signal Compared to the time of failure, more accurate control over the engine 20 is possible.

  On the other hand, when the ECU 100 determines that the crank angle sensor 131 is not abnormal, that is, the crank angle sensor 131 is operating normally (NO in step S11), the ECU 100 executes fail-safe for the crank angle sensor 131. This control process is finished.

  Therefore, even when the crank angle signal fails, that is, even when the output of the crank angle sensor 131 is not normal, the ECU 100 generates a pseudo crank angle signal from the output of the cam angle sensor 130 and can control the engine 20 more accurately. I made it. Thus, even during a failure, it is possible to stabilize the combustion state in the engine 20 and avoid the situation of engine stall. For example, when an abnormality of the crank angle sensor 131 occurs in a vehicle on which the engine 20 is mounted, a malfunction that prevents the vehicle from traveling on its own to a repair shop for repairing the vehicle, occurrence of pre-ignition or knocking, and exhaust pipe 321 Thus, it is possible to avoid a problem such that the catalyst in the catalytic converter 322 extended in the path is damaged by the high heat of the exhaust, and to enable normal operation.

  As described above, when ECU 100 according to the embodiment of the present invention determines normal operation based on the crank angle signal output from crank angle sensor 131, ECU 100 determines the angle difference between the crank angle and the cam angle. While storing as a learning value, if the crank angle signal is not normal, the ECU 100 can generate a pseudo crank angle signal based on the cam angle signal output by the cam angle sensor 130 and the stored learning value. Therefore, even when the crank angle signal is not normal, the engine 20 can be controlled in the same manner as when the crank angle signal is normally output. As a result, even when the output of the crank angle sensor 131 is not normal, the angle difference between the crank angle and the cam angle is reflected in the fail safe control as a learning value, and the combustion state in the engine 20 is stabilized and normal operation is possible. can do.

  In addition, in embodiment mentioned above, although demonstrated as what has one ECU, it is not restricted to this, You may be comprised by several ECU. For example, the ECU 100 of the present embodiment may be configured by a plurality of ECUs such as an E-ECU that performs combustion control of the engine 20 and a T-ECU that performs transmission control of the transmission 30.

  As described above, the control device for an internal combustion engine according to the present invention further ensures fail-safe at the time of failure of the crank angle signal, and even when the output of the crank angle detection means is not normal, occurrence of pre-ignition or knocking The control of the internal combustion engine that controls the ignition timing of the spark plug and the fuel injection timing of the injector has the effect of stabilizing the combustion state in the internal combustion engine and enabling normal operation Useful as a device.

DESCRIPTION OF SYMBOLS 10 Vehicle 20 Engine 21 Cylinder 61 Crank angle signal 63 Cam angle signal 69 Cam angle signal 72 Crank counter 100 ECU (Control device, control means, determination means, storage means, angle difference calculation means, pseudo crank angle signal generation means)
130 Cam angle sensor (cam angle detection means)
131 Crank angle sensor (crank angle detection means)
134 Start switch 135 Throttle sensor 139 Intake cam angle sensor (cam angle detection means)
140 Exhaust cam angle sensor (cam angle detection means)
211 Piston 213 Crankshaft 223 Intake valve 224 Exhaust valve 225 Injector 226 Spark plug 232 Camshaft 241 Intake camshaft 242 Exhaust camshaft 243 Intake cam 244 Exhaust cam 247 Intake side rotation phase controller 248 Exhaust side rotation phase controller 249 Crank sprocket

Claims (3)

Crank angle detection means for detecting a crank angle signal representing the crank angle of the crankshaft of the internal combustion engine, cam angle detection means for outputting a cam angle signal representing the cam angle of the camshaft of the internal combustion engine, the crank angle signal and A control unit for controlling the output of the internal combustion engine based on the cam angle signal;
Determination means for determining whether the detection result of the crank angle detection means is normal;
An angle difference calculating means for calculating an angle difference between the crank angle and the cam angle based on the crank angle signal and the cam angle signal when the determination result of the determining means is normal;
Storage means for storing the angle difference calculated by the angle difference calculation means as a learning value;
Pseudo crank angle signal generating means for generating a pseudo crank angle signal based on the cam angle signal and the learning value stored in the storage means,
The control means stores the learning value in the storage means when the determination result of the determination means is normal, and based on the pseudo crank angle signal when the determination result is not normal, the internal combustion engine A control apparatus for an internal combustion engine characterized by controlling the engine.   2. The pseudo crank angle signal generation means generates the pseudo crank angle signal based on a timing obtained by equally dividing a time interval of a predetermined output timing of the cam angle signal. Control device for internal combustion engine.   The control device for an internal combustion engine according to claim 1 or 2, wherein the determination means determines whether or not a detection result of the crank angle detection means is normal based on a waveform of the crank angle signal. .

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