JP6071463B2 - Internal combustion engine - Google Patents

Description

  The present invention relates to an internal combustion engine capable of determining the stroke of each cylinder at the time of starting in a timely manner.

  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. An ECU (Electronic Control Unit) that controls the operation of the internal combustion engine receives a crank angle signal (N signal) and a cam angle signal (G signal) that are generated along with cranking when starting the internal combustion engine, and controls each cylinder. The stroke is discriminated, and then fuel injection (synchronous injection) and ignition in accordance with the stroke for each cylinder are started.

  However, since it is necessary to start the internal combustion engine as quickly as possible, recently, it is customary to inject fuel into all cylinders simultaneously (asynchronous injection) substantially simultaneously with the start of cranking (for example, (See the following patent document). By performing asynchronous injection in advance, it becomes possible to immediately ignite a cylinder that has reached the ignition timing, that is, compression top dead center immediately after completion of cylinder discrimination, without waiting for fuel injection by synchronous injection. Contributes to shortening the ranking period.

  FIG. 5 shows an arrangement of conventional crank angle signals and cam angle signals. A crank angle sensor that outputs a crank angle signal senses the rotation angle of the rotor that rotates integrally with the crankshaft. The rotor is formed with teeth or protrusions at predetermined angles along the rotation direction of the crankshaft. Typically, every time the crankshaft rotates 10 °, teeth or protrusions are placed. The crank angle sensor faces the outer periphery of the rotor, detects that individual teeth or protrusions pass near the sensor, and transmits a pulse signal as a crank angle signal each time.

  However, 36 pulses are not output during one revolution of the crankshaft. The teeth or protrusions of the crankshaft rotor are partially missing, and due to the missing teeth, the crank angle signal pulse train is also partially missing. In the illustrated example, pulses corresponding to the seventeenth, eighteenth, twentieth, twenty-first, thirty-fifth, and thirty-sixth 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.

  The cam angle sensor that outputs the cam angle signal senses the rotation angle of the rotor that rotates integrally with the intake 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 each time the camshaft rotates 120 °. The camshaft is rotated by receiving a rotational driving force from the crankshaft via a winding transmission mechanism or the like, and its rotational speed is one half of that of the crankshaft. Therefore, the above teeth or protrusions are arranged every 240 ° CA in terms of the crank angle.

  The cam angle sensor faces the outer periphery of the rotor, detects that individual teeth or protrusions pass in the vicinity of the sensor, and transmits a pulse signal as a cam angle signal each time. In the illustrated example, the cam angle signal suggests a timing that is deviated toward the advance side by a certain crank angle from the exhaust top dead center of each cylinder or from the exhaust top dead center.

  The conventional cylinder discrimination method is as follows. That is, when the 35th and 36th pulses missing in the crank angle signal are detected, and the cam angle signal pulse is detected at the same time as the missing, the first cylinder is compressed. It turns out to be in. In this case, the spark ignition is executed at the timing of the compression top dead center of the first cylinder that comes after that, and the expansion stroke in which the fuel injected asynchronously is ignited and burned can be performed.

  In addition, if the 17th, 18th, 20th and 20th first pulse defects included in the crank angle signal are detected and no cam angle signal pulse is detected at the same time, the third cylinder is compressed. It turns out that the dead point has been reached. At this time, an ignition stroke can be performed in which spark ignition is performed in the third cylinder to ignite and burn the asynchronously injected fuel.

  On the other hand, if the 35th and 36th pulses missing in the crank angle signal are detected, but no cam angle signal pulse is detected at the same time, the second cylinder It turns out that it has already exceeded the compression top dead center.

  More specifically, in order to detect a missing pulse of the crank angle signal, it is necessary to further receive a pulse train for 30 ° CA equal to the interval between the pulse immediately before and after the missing pulse. The compression top dead center of the second cylinder matches the timing of the first pulse after the loss of the 35th and 36th pulses, but the 35th and 36th pulses In order to confirm that there was a defect, the first to third pulse trains must be received and compared with the time difference between the thirty-fourth pulse and the first pulse. I must.

  Therefore, the arrival of the compression top dead center of the second cylinder can be known after the reception of the third pulse, that is, after 30 ° CA or more has elapsed from the compression top dead center of the second cylinder. . If the rotation of the crankshaft of the internal combustion engine stops immediately after the first cylinder reaches compression top dead center, ignition is performed in accordance with the timing of the compression top dead center of the second cylinder that comes first when the internal combustion engine restarts. This is not possible (cylinder discrimination is not in time for the compression top dead center of the second cylinder), and the time spent for cranking is increased accordingly.

JP 2012-087733 A

  An object of the present invention is to make it possible to complete cylinder discrimination without delaying the arrival of compression top dead center of each cylinder when starting an internal combustion engine.

In the present invention, the crank angle sensor associated with the crankshaft outputs a crank angle signal every time the crankshaft rotates by a unit angle, but does not output the crank angle signal at a specific rotation phase angle of the crankshaft. The cam angle sensor attached to the camshaft that rotates following the crankshaft and drives the intake valve or exhaust valve to open or close is located near the compression top dead center of each cylinder or the compression top dead center of each cylinder. In addition to outputting a basic cam angle signal at a timing deviated toward the advance side by a predetermined crank angle , an additional cam angle signal is output at a specific rotational phase angle of the camshaft. and the particular base cam angle signal, without sandwiching the loss of the crank angle signal, and at least one click between them a cam angle signal And configure the internal combustion engine, characterized in that can determine stroke of each cylinder based on the link angle signal outputted by intervening.

  According to the present invention, unnecessary fuel injection at the time of starting the internal combustion engine can be reduced.

The figure which shows the whole structure of the internal combustion engine for vehicles in one Embodiment of this invention. The figure which shows typically the aspect of the crank angle sensor accompanying the internal combustion engine of the embodiment. The figure which shows typically the aspect of the cam angle sensor accompanying the internal combustion engine of the embodiment. The timing diagram explaining the content of the cylinder discrimination | determination process performed in the internal combustion engine of the embodiment. The timing diagram explaining the content of the cylinder discrimination | determination performed in the conventional internal combustion engine.

  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 of the present embodiment is a port injection type four-stroke spark ignition engine, and includes three cylinders 1 (one of which is shown in FIG. 1). These cylinders 1 are arranged in series, and the compression top dead center of each cylinder 1 appears at regular intervals, that is, every 240 ° CA.

  In the vicinity of the intake port of each cylinder 1, an injector 11 for injecting fuel is provided. A spark plug 12 is attached to the ceiling of the combustion chamber of each cylinder 1. The spark plug 12 receives spark voltage generated by the ignition coil and causes spark discharge between the center electrode and the ground electrode. The ignition coil is integrally incorporated in a coil case together with an igniter that is a semiconductor switching element.

  The intake passage 3 for supplying intake air takes in air from the outside and guides it to the intake port of each cylinder 1. On the intake passage 3, an air cleaner 31, an electronic throttle valve 32, a surge tank 33, and an intake manifold 34 are arranged in this order from the upstream.

  The exhaust passage 4 for discharging the exhaust guides the exhaust generated as a result of burning the fuel in the cylinder 1 from the exhaust port of each cylinder 1 to the outside. An exhaust manifold 42 and an exhaust purification three-way catalyst 41 are disposed on the exhaust passage 4.

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

  The input interface includes a vehicle speed signal a output from a vehicle speed sensor that detects the actual vehicle speed of the vehicle, a crank angle signal (N signal) b output from an engine rotation sensor that detects the rotation angle of the crankshaft and the engine speed, An accelerator opening signal c output from a sensor that detects the amount of depression of the accelerator pedal or the opening of the throttle valve 32 as an accelerator opening, and a battery that is output from a sensor that detects the voltage (or battery current) of a vehicle-mounted battery A voltage signal d, an intake air temperature / intake air pressure signal e output from a temperature / pressure sensor for detecting intake air temperature and intake air pressure in the intake passage 3 (particularly, the surge tank 33), an internal combustion engine coolant (or coolant) ) Of the coolant temperature signal f output from the fluid temperature sensor for detecting the temperature of the intake camshaft or the exhaust camshaft. The cam angle signal (G signal) g output from the cam angle sensor and the shift range signal h output from the sensor (or shift position switch) for obtaining the shift lever range are input. . The accelerator opening is a so-called required load. The coolant temperature of the internal combustion engine indicates the temperature of the internal combustion engine.

  From the output interface, an ignition signal i is output to the igniter of the spark plug 12, a fuel injection signal j is output to the injector 11, an opening operation signal k is output to the throttle valve 32, and the like.

  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, knows the engine speed, and is filled in the cylinder 1. Estimate the intake volume. Based on the engine speed, the intake air amount, and the like, various operating parameters such as required fuel injection amount, fuel injection timing (including the number of times of fuel injection for one combustion), fuel injection pressure, and ignition timing are determined. As the operation parameter determination method itself, a known method can be adopted. The ECU 0 applies various control signals i, j, k corresponding to the operation parameters via the output interface.

  In addition, the ECU 0 sends a control signal o to a starter motor (or a cell motor, not shown) that is an electric motor when the internal combustion engine is started (a cold start or a return from an idling stop). The cranking is performed by rotating the crankshaft of the internal combustion engine by the starter motor. 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).

  Here, the crank angle signal b and the cam angle signal g will be supplemented. As shown in FIG. 2, the crank angle sensor senses the rotation angle of the rotor 7 that is fixed to the crankshaft and rotates integrally with the crankshaft. The rotor 7 is formed with teeth or protrusions 71 at predetermined angles along the rotation direction of the crankshaft. Typically, every time the crankshaft rotates 10 °, a tooth or projection 71 is placed.

  The crank angle sensor faces the outer periphery of the rotor 7, detects that each tooth or protrusion 71 passes in the vicinity of the sensor, and transmits a pulse signal as the crank angle signal b each time. The ECU 0 receives this pulse as the crank angle signal b.

  However, the crank angle sensor does not output 36 pulses during one rotation of the crankshaft. The teeth or protrusions 71 of the crankshaft rotor 7 are partially missing. In the example shown in FIG. 2, the seventeenth, eighteenth, twentyth, and twentyth first missing tooth portions 72 and the thirty-fifth and thirty-sixth missing tooth portions 73 are roughly divided into two. There are two missing tooth portions 72,73. The missing tooth portions 72 and 73 each correspond to a specific rotational phase angle of the crankshaft. That is, the continuous missing tooth portion 72 corresponds to 180 ° CA and 540 ° CA, and the single missing tooth portion 73 corresponds to 0 ° and 360 ° CA.

  As shown in FIG. 4, due to the above-mentioned missing tooth portions 72 and 73, a part of the pulse train of the crank angle signal b is also lost. 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 (or 360 ° CA), the timing of the nineteenth pulse following the missing eighteenth pulse is 180 °. That is, CA (or 540 ° CA). The timing of the 0 ° CA pulse is substantially equal to the compression top dead center of a specific cylinder (second cylinder in the illustrated example) 1.

  As shown in FIG. 3, the cam angle sensor also senses the rotation angle of the rotor 8 that is fixed to the cam shaft and rotates integrally with the cam shaft. The rotor 8 is formed with teeth or protrusions 81 at every angle obtained by dividing at least one rotation of the camshaft by the number of cylinders. In the case of a three-cylinder engine, each time the camshaft rotates 120 °, teeth or protrusions 81 are arranged.

  The camshaft is rotated by receiving a rotational driving force from the crankshaft via a winding transmission mechanism (chain and sprocket, not shown) and the like, and its rotational speed is half that of the crankshaft. Therefore, the above-described teeth or protrusions 81 are arranged every 240 ° CA in terms of the crank angle.

  In addition, in the present embodiment, the rotor 8 is provided with one tooth or projection 82 for generating an additional cam angle signal g between the teeth or projections 81 every 240 ° CA.

  The cam angle sensor faces the outer periphery of the rotor 8, detects that each tooth or protrusion 81, 82 passes near the sensor, and transmits a pulse signal as the cam angle signal g each time. The ECU 0 receives this pulse as the cam angle signal g.

  The basic cam angle signal g generated due to the teeth or protrusions 81 indicates that any cylinder 1 has reached a predetermined stroke. When a cam angle sensor is attached to the intake camshaft, the basic cam angle signal g output from the cam angle sensor is near the compression top dead center in each cylinder 1 as shown in FIG. This indicates a timing when the crankshaft is deviated from the top dead center by a predetermined crank angle (a value within a range of 30 ° CA to 70 ° CA). In an internal combustion engine with a so-called phase change type variable valve timing mechanism, the cam angle signal g also represents a valve timing adjusted by the mechanism.

  The additional cam angle signal g generated due to the teeth or protrusions 82 corresponds to a specific rotational phase angle of the camshaft (and crankshaft), and assists in determining the stroke of each cylinder 1. Is. In the example shown in FIG. 4, the pulse of the additional cam angle signal g exists at the timing advanced by 60 ° CA from the pulse of the basic cam angle signal g representing the compression top dead center of the first cylinder 1. When these two cam angle signal g pulses are continuously received at an interval of 60 ° CA, which is apparent from the pulse train of the crank angle signal b, the compression top dead center of the first cylinder 1 is immediately after the latter pulse. It turns out that it is.

  The ECU 0 obtains the current stroke of each cylinder 1 by referring to both the crank angle signal b and the cam angle signal g, performs synchronous injection in which fuel is injected at an appropriate fuel injection timing in each cylinder 1, Further, the air-fuel mixture is ignited at an appropriate ignition timing.

  The ECU 0 of the present embodiment performs cranking for rotationally driving the crankshaft by the starter motor when starting the stopped internal combustion engine, and substantially simultaneously with the start of the cranking (immediately before the start of the cranking, At the same time or immediately after starting), asynchronous injection is performed in which fuel is injected into all three cylinders 1 all at once.

  Then, the crank angle signal b and the cam angle signal g generated with the rotation of the crankshaft are received, and the stroke of each cylinder 1 is determined. When the determination of the stroke of each cylinder 1 is completed, synchronous injection and spark ignition for injecting fuel individually for each cylinder 1 are started. During cranking of the internal combustion engine, for each cylinder 1, synchronous injection is performed at a timing immediately before the exhaust top dead center, and spark ignition is performed at a timing immediately after the compression top dead center.

  Hereinafter, a method for determining the stroke of each cylinder 1 after starting cranking of the internal combustion engine will be described. After the start of cranking, the loss of the 35th and 36th pulses included in the crank angle signal b (due to the missing tooth portion 73) is detected, and the cam angle signal g is coincident with the loss. If this pulse is not detected, it is found that the first cylinder 1 is in the compression stroke. In other words, spark ignition is executed at the timing of the compression top dead center of the first cylinder 1 that comes after that (the timing becomes clear by the basic cam angle signal g), and the fuel injected asynchronously is ignited and burned. It can run the expansion stroke.

  Strictly speaking, in order to detect a missing pulse of the crank angle signal b, it is necessary to further receive a pulse train for 30 ° CA equal to the interval between the pulse immediately before and after the missing pulse. . Therefore, the loss of the 35th and 36th pulses is detected and the cylinder discrimination is completed after the third pulse of the crank angle signal b is received.

  After cranking is started, the missing of the 17th, 18th, 20th, and 20th pulses included in the crank angle signal b (due to the missing tooth portion 72) is detected, and the basic cam is detected at the same time. When the pulse of the angle signal g is detected, it is found that the third cylinder 1 has reached the compression top dead center. At this time, spark ignition is executed in the third cylinder 1, and an expansion stroke can be performed in which the fuel injected asynchronously is ignited and burned.

  As already mentioned, the missing of the 17th, 18th, 20th, and 20th first pulses is detected and the cylinder discrimination is completed when the 24th pulse of the crank angle signal b is received. Later. However, the basic cam angle signal g indicating the timing of the compression top dead center of the third cylinder 1 is detected before the 24th crank angle signal b, and the 24th crank angle signal b is Since the timing is in the vicinity of the compression top dead center of the cylinder 1, the cylinder discrimination is in time for the ignition timing, and the third cylinder can be ignited at the compression top dead center.

  Alternatively, after the start of cranking, the additional cam angle signal g (due to the tooth or protrusion 82) is detected, and then the next basic cam angle signal g (tooth) is detected without detecting the missing pulse of the crank angle signal b. When the second cylinder 1 reaches the compression top dead center, it is determined that the second cylinder 1 has reached the compression top dead center. Therefore, it is possible to carry out an expansion stroke in which spark ignition is executed in the second cylinder 1 in accordance with the first crank angle signal b detected next, and the fuel injected asynchronously is ignited and burned.

  As shown in FIG. 4, the additional cam angle signal g is generated before the basic cam angle signal g indicating the compression top dead center timing of the second cylinder 1, and the crank angle signal b is between them. Since there is no deficiency, cylinder discrimination is in time for the ignition timing, and the third cylinder can be ignited at the compression top dead center. Since it is only between the additional cam angle signal g and the basic cam angle signal g that the crank angle signal b is not detected between the cam angle signals g, the compression top dead center of the second cylinder 1 is misidentified. There is no risk of separation.

  In this embodiment, the crank angle sensor attached to the crankshaft outputs the crank angle signal b every time the crankshaft rotates by a unit angle, and outputs the crank angle signal b at a specific rotation phase angle of the crankshaft. The cam angle sensor associated with the camshaft that rotates following the crankshaft and opens and closes the intake valve outputs a basic cam angle signal g corresponding to a predetermined stroke of each cylinder 1. In addition, the additional cam angle signal g is output at a specific rotational phase angle of the camshaft, and the additional cam angle signal g and one of the basic cam angle signals g are An internal combustion engine characterized in that the stroke of each cylinder 1 can be determined on the basis of being output at predetermined crank angle intervals without any missing part. It was.

  According to this embodiment, when starting the internal combustion engine, the cylinder discrimination can be completed without delaying the arrival of the compression top dead center of each cylinder 1, and the first ignition and combustion can be performed early. As a result, it can contribute to shortening of the cranking period.

  The present invention is not limited to the embodiment described in detail above. For example, an electric motor for rotationally driving a crankshaft when starting an internal combustion engine is a motor generator having a function of a generator that generates electric power (particularly, regenerative braking) by receiving rotational driving force from the crankshaft. Sometimes.

  Although the internal combustion engine in the above embodiment is of the port injection type, the present invention can also be applied to start control of a direct injection internal combustion engine that injects fuel directly into the combustion chamber of each cylinder.

  The cam angle sensor may detect a rotation of a rotor fixed to an exhaust cam shaft that rotationally drives the exhaust valve and output a basic cam angle signal and an additional cam angle signal.

  In addition, the specific configuration of each unit, the processing procedure, and the like can be variously modified without departing from the spirit of the present invention.

  The present invention can be used for starting control of an internal combustion engine mounted on a vehicle or the like.

1 ... Cylinder b ... Crank angle signal g ... Cam angle signal

Claims (1)

The crank angle sensor attached to the crankshaft outputs a crank angle signal every time the crankshaft rotates by a unit angle, and at the specific rotation phase angle of the crankshaft, the crank angle signal is output without being output. Yes,
The cam angle sensor attached to the camshaft that rotates following the crankshaft and opens and closes the intake valve or the exhaust valve advances by a predetermined crank angle in the vicinity of the compression top dead center of each cylinder or from the compression top dead center of each cylinder. In addition to outputting the basic cam angle signal at the timing deviated to the corner side , an additional cam angle signal is output at a specific rotational phase angle of the camshaft.
Add a cam angle signal and the particular base cam angle signal, without sandwiching the loss of the crank angle signal, and based on that output by interposing at least one or more crank angle signal between them a cam angle signal An internal combustion engine characterized in that the stroke of each cylinder can be determined.

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