JP2013151926A - Internal combustion engine control device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To start an internal combustion engine, even though crank angle signals and cam angle signals can not be received when starting the internal combustion engine.SOLUTION: All cylinders are ignited in a timing when a voltage value of a battery supplying electricity to a starter motor doing cranking takes the minimum value or the value close to the minimum value, and determination is made that a cylinder in which the time when electric discharging by the igniting is completed is shortest is in a compression stroke, in the case at least one of a crank angle signal and a cam angle signal can not be received when starting an internal combustion engine.

Description

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

  In a four-stroke internal combustion engine having a plurality of cylinders, it is necessary to know which stroke each cylinder is currently in and to perform fuel injection control and ignition control.

  The crankshaft of the internal combustion engine is provided with a crank angle sensor for detecting the rotation angle and the engine speed. The crank angle sensor senses the rotation of the rotor fixed to the crankshaft. Teeth are formed on the outer periphery of the rotor every 10 ° CA (crank angle). The crank angle sensor faces the outer periphery of the rotor, detects that each tooth passes near the sensor, and outputs a pulse signal (crank angle signal) each time. Normally, the crankshaft rotor teeth are partially missing, and it is possible to know the absolute angle of the crankshaft based on the missing crank angle signal pulses due to the missing teeth. Yes.

  Cam angle sensors are also attached to camshafts that open and close the intake valves or exhaust valves of each cylinder. The cam angle sensor also senses the rotation of the rotor fixed to the camshaft. In this rotor, teeth or protrusions are formed at an angle obtained by dividing one rotation by the number of cylinders, or 120 ° (240 ° CA in terms of crank angle) in the case of a three-cylinder engine. Each time passes through the vicinity of the cam angle sensor, the cam angle sensor outputs a pulse signal (cam angle signal).

  The cam angle signal is a signal indicating that any of the plurality of cylinders has reached a predetermined stroke. By referring to the crank angle signal, it is possible to know the timing at which the piston of each cylinder reaches the top dead center or the bottom dead center. However, it is impossible to know whether the top dead center is a compression top dead center or an exhaust top dead center, or whether the bottom dead center is an intake bottom dead center or an expansion bottom dead center. The cam angle signal is useful for determining the type of the top dead center or the bottom dead center.

  Further, when the variable valve timing mechanism is attached to the intake camshaft or the exhaust camshaft, the cam angle signal is also a signal indicating the valve timing implemented by the variable valve timing mechanism. In this case, the phase of the cam angle signal relative to the crank angle signal is advanced or retarded by operation of the variable valve timing mechanism.

  An ECU (Electronic Control Unit), which is a control device for an internal combustion engine, receives a crank angle signal and a cam angle signal, refers to both signals to grasp the stroke of each cylinder, and determines the fuel injection timing and ignition timing in the cylinder. To control the operation of the internal combustion engine (see the following patent document). It is the same when starting the internal combustion engine that the current stroke of each cylinder must be known to perform fuel injection and ignition.

  By the way, although extremely rare, the transmission path between the crank angle sensor and / or the cam angle sensor and the ECU is broken, or the sensor itself breaks down, and the ECU receives the crank angle signal and / or the cam angle signal. It may not be possible. If any of the signals cannot be received, it becomes difficult to know which stroke each cylinder is currently in during cranking in which the engine is rotationally driven by a starter motor (cell motor). Therefore, fuel cannot be injected at an appropriate timing in each cylinder, and there is a risk of starting failure.

JP 2005-207394 A

  An object of the present invention is to enable an internal combustion engine to be started even if a crank angle signal or a cam angle signal cannot be received when the internal combustion engine is started.

  In the present invention, a crank angle signal output from a crank angle sensor that detects a rotation angle of the crankshaft in a predetermined angle unit, and a cam angle signal output from the cam angle sensor at least once during one rotation of the camshaft. In the control device for controlling the internal combustion engine, if at least one of the crank angle signal and the cam angle signal cannot be received when starting the internal combustion engine, the voltage value of the battery that supplies power to the starter motor that performs cranking When all the cylinders are ignited at the timing when a certain value is taken, it is determined that the cylinder with the shortest time until the end of the discharge is in the compression stroke, or the time until the end of the discharge due to this Is determined to be in the intake stroke.

  The voltage required to generate spark discharge in the combustion chamber of the cylinder increases as the pressure (compression pressure) in the combustion chamber, in other words, the density of the gas charged in the cylinder increases. The electrical energy stored in the ignition coil to apply a high voltage to the spark plug electrode is finite. The higher the density of the gas charged in the cylinder, the faster the ignition coil energy is consumed due to dielectric breakdown. Therefore, the discharge period is shortened.

  The present invention has been made by paying attention to the above points for the first time, spark discharge is simultaneously generated in all the cylinders, and it is determined that the cylinder having the shortest time until the discharge is in the compression stroke, Alternatively, the current stroke of each cylinder is known by determining that the cylinder having the longest time until the discharge ends is in the intake stroke. Then, the fuel is injected into the cylinder which is judged to be in the intake stroke or the compression stroke.

  The difference in time from ignition to the end of discharge between the cylinders is considered to increase as the amount of intake air charged in the cylinders increases. Therefore, when at least one of the crank angle signal and the cam angle signal cannot be received at the time of starting the internal combustion engine, it can be said that it is preferable to correct the intake air amount as compared with the case where it is not.

  It is convenient to measure the time until the discharge due to ignition in each cylinder is completed using a circuit that detects an ionic current flowing through the electrode of the spark plug during combustion in each cylinder.

  According to the present invention, the internal combustion engine can be started even if the crank angle signal or the cam angle signal cannot be received when the internal combustion engine is started.

The figure which shows schematic structure of the internal combustion engine in one Embodiment of this invention. The figure which shows the circuit which detects the ion current (voltage between electrodes of a spark plug) in the embodiment. The timing diagram which shows transition of the battery voltage during crank angle signal, cam angle signal, and cranking in the same embodiment. The figure which shows transition of the voltage between electrodes generated by the spark discharge of the ignition plug in the embodiment.

  An embodiment of the present invention will be described with reference to the drawings. FIG. 1 shows an outline of an internal combustion engine for a vehicle in the present embodiment. The internal combustion engine in the present embodiment is a spark ignition type four-stroke engine. The internal combustion engine of the illustrated example is of an in-cylinder direct injection type, and includes a plurality of cylinders 1 (one of which is shown in FIG. 1), an injector 10 for injecting fuel into each cylinder 1, An intake passage 3 for supplying intake air to each cylinder 1, an exhaust passage 4 for discharging exhaust from each cylinder 1, an exhaust turbocharger 5 for supercharging intake air flowing through the intake passage 3, and exhaust An external EGR device 2 that recirculates EGR gas from the passage 4 toward the intake passage 3 is provided.

  A spark plug 13 is attached to the ceiling of the combustion chamber of the cylinder 1. FIG. 2 shows an electric circuit for spark ignition. The spark plug 13 receives spark voltage generated by the ignition coil 12 and causes spark discharge between the center electrode and the ground electrode. The ignition coil 12 is integrally incorporated in a coil case together with an igniter 11 that is a semiconductor switching element.

  When the igniter 11 receives an ignition signal i from the ECU 0 which is a control device for the internal combustion engine, the igniter 11 is first ignited and a current flows to the primary side of the ignition coil 12, and the igniter 11 is extinguished at the ignition timing immediately thereafter. The lever current is cut off. Then, a self-induction action occurs, and a high voltage is generated on the primary side. Since the primary side and the secondary side share the magnetic circuit and the magnetic flux, a higher induced voltage is generated on the secondary side. This high induction voltage is applied to the center electrode of the spark plug 13, and spark discharge occurs between the center electrode and the ground electrode.

  During normal operation, the ECU 0 detects an ionic current generated in the combustion chamber of the cylinder 1 when the fuel explodes and burns, and refers to this ionic current to a period from the latter stage of the compression stroke to the latter stage of the expansion stroke. The combustion pressure in the combustion chamber (cylinder pressure) is estimated.

  As shown in FIG. 2, the electrical circuit for spark ignition has a bias power supply unit 14 for effectively detecting the ionic current, and an amplification that amplifies and outputs a detection voltage corresponding to the amount of the ionic current. The part 15 is attached. The bias power supply unit 14 includes a capacitor 141 that stores a bias voltage, a Zener diode 142 for increasing the voltage of the capacitor 141 to a predetermined voltage, current blocking diodes 143 and 144, and a load that outputs a voltage corresponding to the ion current. A resistor 145. The amplifying unit 15 includes a voltage amplifier 151 typified by an operational amplifier.

  During arc discharge between the center electrode of the spark plug 13 and the ground electrode, the capacitor 141 is charged, and then a high bias voltage due to the charge charged in the capacitor 141 is applied to the center electrode of the spark plug 13. With this bias voltage, an ion current flows through the load resistor 145. The voltage between both ends of the resistor 145 generated due to the flow of the ionic current is amplified by the amplifying unit 15 and received by the ECU 0 as the ionic current signal h.

  At the time of poor combustion such as over lean, the combustion becomes excessively slow compared with that at the time of normal combustion. Then, the peak of the ionic current becomes low, and the time during which the ionic current flows is long. The transition of the ionic current is measured, and it is determined whether the maximum value exceeds the determination threshold or whether the time during which the ionic current exceeds the determination threshold (this threshold is different from the threshold) is short or long. Thus, it is possible to determine whether or not the combustion in the cylinder 1 is normal. If the ion current cannot be detected, a misfire has occurred in the cylinder 1.

  The intake valve 16 is accompanied by a variable valve timing mechanism 161 that can change the opening / closing timing thereof. The variable valve timing mechanism 161 advances or retards the opening / closing timing of the intake valve 16, for example, by changing the rotational phase of the intake camshaft with respect to the crankshaft.

  The intake passage 3 takes in air from the outside and guides it to the intake port of the cylinder 1. On the intake passage 3, an air cleaner 31, a compressor 51 of the supercharger 5, an intercooler 32, an electronic throttle valve 33, a surge tank 34, and an intake manifold 35 are arranged in this order from the upstream side.

  The exhaust passage 4 guides the exhaust generated by burning the fuel in the cylinder 1 from the exhaust port of the cylinder 1 to the outside. An exhaust manifold 42, a drive turbine 52 for the supercharger 5, and a three-way catalyst 41 are disposed on the exhaust passage 4. In addition, an exhaust bypass passage 43 that bypasses the turbine 52 and a waste gate valve 44 that is a bypass valve that opens and closes the inlet of the bypass passage 43 are provided. The waste gate valve 44 is an electric waste gate valve that can be opened and closed by inputting a control signal l to the actuator, and a DC servo motor is used as the actuator.

  The exhaust turbocharger 5 is configured such that the drive turbine 52 and the compressor 51 are connected and linked in a coaxial manner. Then, the driving turbine 52 is rotationally driven by using the energy of the exhaust gas, and the compressor 51 is pumped by using the rotational force, whereby the intake air is pressurized and compressed (supercharged) and sent to the cylinder 1.

  The external EGR device 2 realizes a so-called high-pressure loop EGR. The inlet of the external EGR passage is connected to a predetermined location upstream of the turbine 52 in the exhaust passage 4. The outlet of the external EGR passage is connected to a predetermined location downstream of the throttle valve 33 in the intake passage 3, specifically to a surge tank 34. An EGR cooler 21 and an EGR valve 22 are also provided on the external EGR passage.

  The ECU 0 as the control device for the internal combustion engine of the present embodiment is a microcomputer system having a processor, a memory, an input interface, an output interface, and the like.

  The input interface of the ECU 0 includes a vehicle speed signal a output from a vehicle speed sensor that detects the vehicle speed, a crank angle signal (N signal) b output from a crank angle sensor that detects the rotation angle of the crankshaft and the engine speed, and an accelerator. An accelerator opening signal c output from an accelerator opening sensor that detects the depression amount of the pedal or the opening of the throttle valve 33 as an accelerator opening (in other words, a required load), an intake passage 3 (in particular, a surge tank 34) An intake air temperature / intake pressure signal d output from a temperature / pressure sensor that detects intake air temperature and intake pressure (or supercharging pressure), a battery voltage signal e output from a sensor that detects the voltage of an on-vehicle battery, an internal combustion engine Cam angle sensor based on a coolant temperature signal f output from a coolant temperature sensor for detecting the coolant temperature of the engine, and a plurality of cam angles of the intake camshaft A cam angle signal et output (G signal) g, the ion current signal h or the like to be output from the circuit for detecting an ion current caused by the combustion of the mixture in the combustion chamber are inputted.

  From the output interface of the ECU 0, an ignition signal i for the igniter, an opening / closing timing control (phase angle) signal j for the variable valve timing mechanism 161, an opening operation signal k for the throttle valve 33, and a waste gate valve 44 On the other hand, an opening operation signal l, an opening operation signal m for the EGR valve 22, a fuel injection signal n for the injector 10, a control signal o for controlling the driving of the starter motor, and the like are output. The starter motor rotates upon receipt of electric power from the in-vehicle battery.

  The processor of the ECU 0 interprets and executes a program stored in the memory in advance, calculates operation parameters, and controls the operation of the internal combustion engine. The ECU 0 acquires various information a, b, c, d, e, f, g, and h necessary for operation control of the internal combustion engine via the input interface, and knows the intake pressure and the engine speed, and the cylinder 1 The amount of intake air charged into the engine is estimated, and the required fuel injection amount, fuel injection timing (including the number of fuel injections per combustion), fuel injection pressure, ignition timing, opening / closing timing of the intake valve 16, EGR amount ( Alternatively, various operation parameters such as the EGR rate and the opening degree of the EGR valve 22 are determined. The ECU 0 applies various control signals i, j, k, l, m, and n corresponding to the operation parameters via the output interface.

  Further, the ECU 0 inputs a control signal o to the starter motor when the internal combustion engine is started (a cold start or a return from an idling stop), and the starter motor pinion gear is used as a flywheel. (MT vehicle) or drive plate (AT vehicle) is engaged with a ring gear on the outer periphery to perform cranking for rotating the engine. Cranking ends from the first explosion to the consecutive explosion, and ends when the engine speed exceeds a threshold determined according to the cooling water temperature or the like (assuming that the explosion has been completed).

  It supplements regarding the crank angle signal b and the cam angle signal g. The crank angle sensor senses the rotation angle of a rotor that is fixed to the crankshaft and rotates integrally with the crankshaft. The rotor is formed with teeth at a predetermined angle, for example, every 10 ° CA. The crank angle sensor detects that each tooth of the rotor 7 passes in the vicinity of the sensor, and transmits a pulse signal as the crank angle signal b each time.

  However, the teeth of the rotor of the crankshaft are partially missing, and due to the missing teeth, the crank angle signal pulse is also partially missing as shown in FIG. In the example shown in FIG. 3, pulses corresponding to the 17th, 18th, 20th, 21st, 35th, and 36th pulses are missing. Based on this defect, it is possible to know the absolute angle of the crankshaft. If the timing of the first pulse after the missing thirty-sixth pulse is 0 ° CA, the timing of the nineteenth pulse following the missing eighteenth pulse is 180 ° CA.

  On the other hand, the cam angle sensor senses the rotation angle of a rotor that is fixed to the camshaft and rotates integrally with the camshaft. The rotor is formed with teeth or protrusions for each angle obtained by dividing one rotation of the camshaft by the number of cylinders. In the case of a three-cylinder engine, teeth or protrusions are arranged every 120 ° (240 ° CA in terms of crank angle). The cam angle sensor detects that individual teeth or protrusions pass in the vicinity of the sensor, and transmits a pulse signal as the cam angle signal g each time.

  The cam angle signal g is a signal indicating that any one of the cylinders 1 has reached a predetermined stroke. In this embodiment, a cam angle sensor is attached to the intake camshaft, and the cam angle signal suggests the start of the intake stroke in each cylinder 1 as shown in FIG. In addition, the cam angle signal g represents the opening timing of the intake valve 16 adjusted by the variable valve timing mechanism 161.

  The phase of the cam angle signal g is changed by the advance / retard operation of the opening / closing timing of the intake valve 16 by the variable valve timing mechanism 161. In the present embodiment, the reference phase is set to the state where the opening timing of the intake valve 16 is most retarded, that is, the operation region (including idling) where the engine speed is low or the engine is started. The cam angle signal g shown in FIG. 3 is for the reference phase. When the engine speed increases and the opening timing of the intake valve 16 advances, the output timing of the cam angle signal g is advanced. At this time, the phase of the cam angle signal g is displaced to the left in FIG.

  When the internal combustion engine is started, the ECU 0 can normally know the current stroke of each cylinder 1 during cranking by referring to both the crank angle signal b and the cam angle signal g. Therefore, it is easy to set appropriate fuel injection timing and ignition timing in each cylinder 1.

  However, when the ECU 0 cannot receive at least one of the crank angle signal b and the cam angle signal g, the current stroke of each cylinder 1 is obtained by a method that does not depend on both the signals b and g, and the fuel is detected. The injection timing and ignition timing must be determined.

  Therefore, in this embodiment, the ignition signal i is input to the igniters 11 of all the cylinders 1 at a timing at which the value of the battery voltage e that supplies power to the starter motor that performs cranking takes a certain value, and all cylinders A spark discharge is caused in one spark plug 13. After that, the time until the spark discharge in each cylinder 1 is completed is measured, and the cylinder 1 with the shortest time is determined to be the cylinder 1 currently in the compression stroke.

  As shown in FIG. 3, during cranking by the starter motor, the voltage e of the battery that supplies power to the starter motor periodically fluctuates. The battery voltage e decreases most when any cylinder 1 is near the compression top dead center. In particular, if the internal combustion engine is a three-cylinder engine, when one cylinder 1 is at compression top dead center, the other two cylinders 1 are in the second half of the intake stroke and the first half of the exhaust stroke, respectively. The mechanical load on the starter motor becomes the largest, so the battery voltage e drops and takes a minimum value.

  In short, the timing at which the battery voltage e takes the minimum value coincides with the timing at which one of the cylinders 1 reaches the compression top dead center. The same applies to internal combustion engines with different numbers of cylinders, such as a four-cylinder engine.

  The ignition timing at the start of the internal combustion engine is usually near the compression top dead center. Accordingly, when the battery voltage e becomes a minimum value, decreases to a predetermined value close to the minimum value, or increases to a predetermined value close to the minimum value after the minimum value arrives, the igniter of all cylinders 1 from the ECU 0 At the same time, an ignition signal i is input to 11 and ignition is performed by the spark plugs 13 of all cylinders 1. Then, the air-fuel mixture can be ignited at an appropriate timing in any cylinder 1.

  FIG. 4 illustrates the transition of the voltage of the spark discharge generated between the center electrode and the ground electrode of the spark plug 13. If the pressure in the combustion chamber of the cylinder 1, in other words, the density of the gas filled in the cylinder 1 is high, the voltage required to cause dielectric breakdown between the electrodes of the spark plug 13 increases. Therefore, as indicated by a solid line in FIG. 4, the voltage in the capacity discharge at the initial stage of the spark discharge increases. In addition, the energy stored in the ignition coil 12 to cause dielectric breakdown is consumed quickly. Therefore, as shown by the solid line in FIG. 4, the period of voltage fluctuation accompanying the induction discharge following the capacitive discharge is shortened.

  On the contrary, if the density of the gas filled in the cylinder 1 is low, the voltage necessary for causing dielectric breakdown between the electrodes of the spark plug 13 is reduced, and the energy stored in the ignition coil 12 is also consumed slowly. become. Therefore, as indicated by a broken line in FIG. 4, the voltage in the capacitive discharge becomes small, and the period of voltage fluctuation accompanying the induction discharge becomes long.

  That is, the same energy is applied to the ignition coils 12 of all the cylinders 1, spark discharge is generated by the spark plugs 13 of all the cylinders 1, and the cylinder 1 having the shortest time from the start of capacitive discharge to the end of induction discharge is selected. Thus, it is possible to determine the cylinder 1 that is currently in the compression stroke.

The ECU 0 receives the voltage signal h corresponding to the capacitive discharge and the induction discharge, which is emitted from the electrode of the ignition plug of each cylinder 1 through the circuit for measuring the ionic current shown in FIG. The discharge time for each cylinder _{1 T n [n = 1,2,} ......, x (x is a cylinder the total number of 1)] was measured, based on the measured _{T n, T 1 / T 2} , ... ..., and calculates _{T x-1 / T x,} T x / T 1 , respectively.

In the case of a three-cylinder engine, three values of T ₁ / T ₂ , T ₂ / T ₃ , and T ₃ / T ₁ are calculated. Of the calculated values, the cylinder 1 corresponding to the denominator at the largest value is the cylinder 1 in the compression stroke. For example, if T ₂ / T ₃ is the largest, it is determined that the third cylinder 1 is in the compression stroke. Thus, as shown in FIG. 3, if the third cylinder 1 is in the current compression stroke, particularly near the compression top dead center, the first cylinder 1 is in the latter half of the current intake stroke, and the second cylinder 1 It is clear that is currently in the first half of the exhaust stroke.

  The ECU 0 knows the current stroke of each cylinder 1 and then injects a fuel injection signal to the injector 10 attached to the cylinder 1 in order to inject fuel into the cylinder 1 which is determined to reach the next intake stroke or compression stroke. Enter n. For example, in a three-cylinder engine, when the third cylinder 1 is determined to be in the vicinity of the compression top dead center during cranking, the first cylinder 1 is in the intake stroke. Fuel is injected into the first cylinder 1 at an appropriate timing before compression top dead center.

  Thereafter, the next ignition timing obtained by referring to the battery voltage e (as described above, the battery voltage e has become a minimum value, has decreased to a predetermined value close to the minimum value, or has reached a minimum value. After that, the ignition signal i is input to the igniter 11 of the first cylinder 1 at a timing at which the ignition signal i is increased to a predetermined value close to the minimum value. As a result, the fuel in the air-fuel mixture filled in the first cylinder 1 can be properly ignited.

  Further, the fuel is injected into the second cylinder 1 that is currently in the intake stroke, and the second cylinder 1 is ignited at an ignition timing that is known with reference to the battery voltage e. The fuel injection and the ignition are executed sequentially.

  Incidentally, when the internal combustion engine is started when the ECU 0 cannot receive the crank angle signal b and / or the cam angle signal g, correction control for increasing the amount of intake air charged in the cylinder 1 is performed as compared with the case where the ECU 0 is not. It is preferable to do. The intake air amount increase correction can be realized by greatly expanding the opening degree of the electronic throttle valve 33 during cranking (inputting such an opening operation signal k to the throttle valve 33).

  The increase correction of the intake air amount is performed by increasing the gas density in the combustion chamber of the cylinder 1 in the compression stroke, the spark discharge time in the cylinder 1 in the compression stroke, and the spark discharge time in the other cylinders 1 This is to widen the difference.

  In this embodiment, the crank angle signal b output from the crank angle sensor that detects the rotation angle of the crankshaft in units of a predetermined angle, and the angle unit obtained by dividing the rotation angle of the camshaft by one rotation of the camshaft by the number of cylinders. The control device 0 that controls the internal combustion engine with reference to the cam angle signal g output from the cam angle sensor detected in step 1 receives at least one of the crank angle signal b and the cam angle signal g when the internal combustion engine is started. If not, all the cylinders 1 are ignited at a timing when the voltage value e of the battery that supplies power to the starter motor that performs cranking takes a specific value, and the time required until the discharge is completed is the shortest cylinder 1 Was determined to be in the compression stroke.

  According to the present embodiment, even if the crank angle signal b or the cam angle signal g is lost, a fail safe is realized in which the current stroke of each cylinder 1 can be grasped and the internal combustion engine can be started. .

  In addition, when at least one of the crank angle signal b and the cam angle signal g cannot be received when the internal combustion engine is started, the intake air amount is corrected to be increased as compared with the case where the crank angle signal b or the cam angle signal g is not received. The time difference until the end of the spark discharge between the cylinder 1 in the cylinder 1 and the cylinder 1 that is not is larger, and it is possible to reliably determine the cylinder 1 in the compression stroke.

  Further, since the time until the discharge due to ignition in each cylinder 1 is completed is measured using a circuit that detects the ionic current flowing through the electrode of the spark plug 13 during combustion in each cylinder 1, a separate circuit or There is no need to add sensors and the cost is not increased.

  The present invention is not limited to the embodiment described in detail above. In the above-described embodiment, the ECU 0 refers to the battery voltage e and performs ignition in all the cylinders 1 when this reaches a specific value (that is, a minimum value or a predetermined value close to the minimum value). On the other hand, the ECU 0 can still receive either the crank angle signal b or the cam angle signal g. With reference to the receivable signals b and g, the compression top dead center of one of the cylinders 1 or the vicinity thereof. The timing can be detected (for example, unlike the above-described embodiment, a pulse of the cam angle signal g is generated in the vicinity of the compression top dead center of any cylinder 1, which indicates the start of the expansion stroke of any cylinder 1. In other cases, ignition may be performed at the timing detected based on the receivable signals b and g. Also in this case, there is no change in that all the cylinders 1 are ignited at the timing when the battery voltage e takes a specific value.

  In the above embodiment, the opening degree of the electronic throttle valve 33 is manipulated to correct the increase / decrease of the intake air amount during cranking. However, in an internal combustion engine equipped with an idle speed control valve, the idle speed control valve The intake air amount may be corrected by increasing the opening degree. As is well known, the idle speed control valve is a flow control valve that opens and closes a bypass passage that communicates the upstream side and the downstream side of the throttle valve in the intake passage.

  In the above embodiment, the cam angle sensor is provided on the intake camshaft side, but this does not hinder the aspect in which the cam angle sensor is provided on the exhaust camshaft side. In particular, when the exhaust valve 17 is accompanied by a variable valve timing mechanism, a cam angle sensor for detecting the rotational phase of the exhaust camshaft and the valve timing of the exhaust valve 17 is essential. The cam angle signal in this case indicates, for example, the start of the exhaust stroke in each cylinder 1 and represents the opening timing of the exhaust valve 17.

  The cam angle sensor in the above embodiment outputs a cam angle signal g each time the cam shaft rotates by an angle obtained by dividing 360 ° (this is not the crank angle) by the number of cylinders. However, the cam angle signal g is originally referred to in order to grasp the current stroke of each cylinder 1 in combination with the crank angle signal b. Therefore, the cam angle signal g may be generated at least once every time the camshaft rotates once.

  In the above embodiment, it has been determined that the cylinder 1 having the shortest time until the spark discharge ends is in the compression stroke, but instead of this, or together with this, the time until the spark discharge ends is the longest. It may be determined that the cylinder 1 is in the intake stroke. The method of discriminating the cylinder 1 with the longest discharge as the intake stroke can be applied not only to a three-cylinder engine but also to a four-cylinder engine or the like.

  Needless to say, the number of cylinders of the internal combustion engine is not limited to three cylinders.

  Other specific configurations of each part can be variously modified without departing from the spirit of the present invention.

  The present invention can be applied to control at the start of a spark ignition type internal combustion engine mounted on a vehicle or the like.

0 ... Control unit (ECU)
DESCRIPTION OF SYMBOLS 1 ... Cylinder 13 ... Spark plug b ... Crank angle signal e ... Battery voltage g ... Cam angle signal

Claims (3)

With reference to a crank angle signal output from a crank angle sensor that detects a rotation angle of the crankshaft in a predetermined angle unit, and a cam angle signal output from the cam angle sensor at least once during one rotation of the camshaft, In a control device for controlling an internal combustion engine,
When at least one of the crank angle signal and the cam angle signal cannot be received when starting the internal combustion engine, ignition is performed for all cylinders at a timing when the voltage value of the battery that supplies power to the starter motor that performs cranking takes a certain value. And determine that the cylinder with the shortest time until the discharge is completed is in the compression stroke, or determine that the cylinder with the longest time until the discharge is in the intake stroke A control device for an internal combustion engine. 2. The control device for an internal combustion engine according to claim 1, wherein when at least one of the crank angle signal and the cam angle signal cannot be received at the time of starting the internal combustion engine, the intake air amount is corrected to be increased as compared with the case where it is not. The internal combustion engine according to claim 1 or 2, wherein the time until the discharge due to ignition in each cylinder is completed is measured using a circuit that detects an ionic current flowing through the electrode of the spark plug during combustion in each cylinder. Control device.

Images