JP2019044621A - Engine starting control device and engine starting method - Google Patents

Abstract

To provide an engine starting control device and an engine starting method for adjusting the opening of a throttle valve to a starting target opening appropriate for engine start at the engine start, actualizing more reliable engine start while enabling a stable engine speed earlier.SOLUTION: An engine starting control device 9 for adjusting the opening of a throttle valve 2 to a starting target opening appropriate for engine start at the engine start detects that a crank angle becomes a predetermined reference angle firstly after cranking start and controls the opening of the throttle valve 2 to be the starting target opening before the stroke determination of a cylinder of an engine 20 on the basis of the detection.SELECTED DRAWING: Figure 1

Description

  The present invention relates to an engine start control device and an engine start method.

  For example, as disclosed in Patent Document 1, a motorcycle or the like is provided with a throttle valve, and the intake amount to the engine is adjusted by adjusting the opening degree of the throttle valve. When starting such an engine from a stopped state, it is preferable to raise the engine speed early in order to stabilize the engine speed in a short time. For this reason, at the time of engine start, the opening degree of the throttle valve is set large (start target opening degree) so that more air is supplied to the engine than the intake amount required at the time of idling.

International Publication No. 2012/091014

  By the way, in order to stabilize the engine speed early, it is preferable to set the opening degree of the throttle valve to the target opening degree as early as possible. Therefore, it is conceivable to set the opening degree of the throttle valve to the start target opening degree when the ignition switch is turned on.

  However, when the ignition switch is turned on and the throttle valve starts to open at the target opening degree, the throttle valve becomes the target opening degree at the start of cranking. For this reason, a large amount of air flows into the cylinder of the engine at the start of cranking, and the torque of the crankshaft required for the compression of the air flowing into the cylinder increases. For example, when the battery is exhausted or engine friction increases due to low temperature or the like, there is a possibility that the torque required to compress the air flowing into the cylinder can not be obtained. In such a case, the startability of the engine may deteriorate or the engine may not start.

  The present invention has been made in view of the above-mentioned problems, and an engine start control device and an engine start method for adjusting an opening degree of a throttle valve to a start target opening suitable for engine start at the engine start. An object of the present invention is to more reliably start the engine while making it possible to stabilize the rotational speed.

  The present invention adopts the following configuration as means for solving the above-mentioned problems.

  The first invention is an engine start control device that adjusts the opening degree of the throttle valve to a start target opening degree suitable for engine start at the time of engine start, and the crank angle is initially set to a predetermined reference angle after cranking starts. The present invention adopts a configuration in which the opening degree of the throttle valve is controlled to be the start target opening degree before the stroke of the cylinder provided in the engine is determined based on the detection.

  According to a second aspect of the present invention, in the first aspect, at the start of cranking, the opening degree of the throttle valve is controlled to be the minimum opening degree set so that the engine can idle.

  According to a third aspect of the present invention, in the first or second aspect, the crank angle at which at least one of the cylinders takes an intake stroke is set to the reference angle.

  According to a fourth aspect of the invention, in any one of the first to third aspects, the opening degree of the throttle valve is set to the start target opening degree prior to simultaneous injection for simultaneously supplying fuel to the plurality of cylinders. Adopt the configuration.

  A fifth invention is an engine starting method for adjusting the opening degree of the throttle valve to a starting target opening degree suitable for engine starting at the time of engine starting, and the crank angle is initially set to a predetermined reference angle after cranking starts. It is detected that it has become, and a configuration is adopted in which the opening degree of the throttle valve is set to the start target opening degree before the stroke of the cylinder provided in the engine is determined based on the detection.

  According to the present invention, after the start of cranking, it is controlled that the throttle valve reaches the start target opening degree after detecting that the crank angle first reaches the predetermined reference angle. Therefore, it is possible to prevent a large amount of air from flowing into the cylinder of the engine at the start of cranking, and improve the startability of the engine. Furthermore, after the crank angle first reaches the reference angle, the throttle valve reaches the start target opening before the stroke of the cylinder is determined, so the engine rotational speed can be raised early, and the engine rotational speed stabilizes early It can be done. Therefore, according to the present invention, in the engine start control device and the engine start method for adjusting the opening degree of the throttle valve to the start target opening degree suitable for the engine start at the engine start, the engine rotational speed can be stabilized early. It becomes possible to start the engine more reliably.

FIG. 1 is a block diagram showing a schematic configuration of an engine control system including a function as an engine start control device according to an embodiment of the present invention. It is a timing chart which shows the injection timing of the fuel in an injector, the ignition timing by an ignition coil, the opening degree of a throttle valve, the on-off state of an ignition switch, and the on-off state of a starter switch. It is a flowchart which shows the processing flow at the time of the engine start of ECU which the engine control system containing the function as an engine start control apparatus of one Embodiment of this invention has.

  Hereinafter, an embodiment of an engine start control device and an engine start method according to the present invention will be described with reference to the drawings. In the following drawings, the scale of each member is appropriately changed in order to make each member have a recognizable size.

  FIG. 1 is a block diagram showing a schematic configuration of an engine control system 1 including a function as an engine start control device of the present embodiment. The engine control system 1 is a system for controlling the number of revolutions of an engine 20 mounted on a motorcycle or the like. The engine 20 in the present embodiment is a reciprocating engine having three cylinders (a first cylinder 21, a second cylinder 22 and a third cylinder 23). Such an engine 20 includes, for each cylinder, an injector for injecting fuel and an ignition coil for igniting a mixture containing fuel. In the following description, the injector and the ignition coil installed in the first cylinder 21 will be referred to as the first injector 21a and the first ignition coil 21b, if necessary, and the injector and the ignition coil installed in the second cylinder 22 Are referred to as a second injector 22a and a second ignition coil 22b, and an injector and an ignition coil installed in the third cylinder 23 are referred to as a third injector 23a and a third ignition coil 23b. The first injector 21a, the second injector 22a, and the third injector 23a are disposed, for example, at ports connected to the combustion chambers of the respective cylinders, and the first ignition coil 21b, the second ignition coil 22b, and the third ignition The coil 23 b is disposed in the combustion chamber of each cylinder.

  The first cylinder 21, the second cylinder 22, and the third cylinder 23 each have an intake stroke for taking air into the cylinder, a compression stroke for compressing the air, an explosion stroke for burning the air and fuel, and a combustion. The exhaust stroke for exhausting the gas from the cylinders is sequentially performed. The same stroke in each cylinder is started at different crank angles. For example, the intake stroke of the first cylinder 21, the intake stroke of the second cylinder 22, and the intake stroke of the third cylinder 23 are started at different timings (that is, different crank angles) in time series.

  Further, for the engine 20, a temperature sensor 24 and a crank angle sensor 25 are installed. The temperature sensor 24 measures the temperature of the cooling water of the engine 20, and outputs a signal indicating the measurement result. The crank angle sensor 25 outputs a pulse signal indicating passage of a rotor tooth fixed to the crankshaft of the engine 20 and rotated with the crankshaft. The pulse interval of such a pulse signal indicates the number of revolutions of the engine 20. That is, the crank angle sensor 25 outputs a signal including the number of revolutions of the engine 20.

  Further, in the present embodiment, the rotor has a plurality of teeth arranged in the circumferential direction at equal intervals, but has a missing tooth region (a region where no teeth are provided) at one location in the circumferential direction. There is. The non-toothed area is arranged so that the crankshaft is located within the measurement range of the crank angle sensor 25 when the first cylinder 21 has a crank angle at the initial stage of the intake stroke. That is, in the pulse signal output from the crank angle sensor 25, when the first cylinder 21 reaches the crank angle at the initial stage of the intake stroke, pulses at substantially equal intervals are lost. In the present embodiment, a crank angle at which a pulse is lost in a pulse signal output from the crank angle sensor 25 is used as a reference angle. That is, in the present embodiment, the reference angle of the crankshaft is set to the crank angle at which the first cylinder 21 is in the initial stage of the intake stroke. That is, the reference angle is set to a crank angle at which the first cylinder 21 which is any one of the plurality of cylinders (the first cylinder 21, the second cylinder 22 and the third cylinder 23) takes an intake stroke.

  As shown in FIG. 1, the engine control system 1 of the present embodiment includes a throttle valve 2, a valve drive motor 3, a cell motor 4, a relay 5, a starter switch 6, an ignition switch 7, and a battery 8. An engine start control device 9 is provided.

  The throttle valve 2 is a valve for adjusting the intake amount of the engine 20. The throttle valve 2 is provided with a disc-shaped valve element capable of changing its attitude, and adjusts the passing amount of air (that is, the intake amount of the engine 20) by changing the inclination angle with respect to the flow direction of the valve element. . The valve drive motor 3 is, for example, a three-phase brushless motor, and the output shaft is coupled to the valve body of the throttle valve 2 via a reduction gear (not shown). The valve drive motor 3 is rotated in response to a three-phase drive signal input from a throttle valve controller 9 b of the engine start control device 9 described later.

  The cell motor 4 is a DC motor that generates rotational power by DC power supplied from the battery 8, and is connected to the crankshaft of the engine 20. The cell motor 4 is connected to the battery 8 through the relay 5 and the ignition switch 7 and is electrically connected to the battery 8 when the ignition switch 7 is on and the relay 5 can be energized. Ru. Such a cell motor 4 performs so-called cranking by converting DC power supplied from the battery 8 into rotational power and transmitting it to the crankshaft of the engine 20 when connected to the battery 8.

  The relay 5 is disposed between the cell motor 4 and the ignition switch 7 and electrically connects the battery 8 and the cell motor 4 via the ignition switch 7 while the starter switch 6 is pressed. The starter switch 6 is installed, for example, on the handle portion of the motorcycle, and is a switch that enables the relay 5 to be energized while being pressed by an occupant. The ignition switch 7 is, for example, a switch connected by inserting and rotating a key (not shown). When the ignition switch 7 is turned on, the electric power of the battery 8 is supplied to an ECU 9a and a throttle valve controller 9b which will be described later of the engine start control device 9. When the ignition switch 7 is turned on, the electric power of the battery 8 can be supplied to the cell motor 4 through the relay 5. The battery 8 is connected to the engine start control device 9 via the ignition switch 7. Also, the battery 8 is connected to the cell motor 4 via the ignition switch 7 and the relay 5.

  The engine start control device 9 includes an ECU (Engine Control Unit) 9a and a throttle valve controller 9b. The ECU 9a centrally controls the operating state of the engine 20, and includes an MPU (Micro-processing unit) that performs arithmetic processing, a memory that stores various data, programs, and the like. Such an ECU 9a calculates, for example, the opening degree of the throttle valve 2 based on the input from the temperature sensor 24, the crank angle sensor 25 or the like, and outputs a control signal indicating the calculated opening degree of the throttle valve 2 to the throttle valve controller Enter 9b. Further, the ECU 9a controls the first injector 21a, the first ignition coil 21b, the second injector 22a, the second ignition coil 22b, the third injector 23a, the third ignition coil 23b, based on the input from the temperature sensor 24, the crank angle sensor 25 and the like. Do also. The ECU 9a not only controls the engine start but also controls the operation of the engine 20 after the start.

  The ECU 9a controls the opening degree of the throttle valve 2 in control for starting the engine 20 from a stop state (engine start control). As will be described in detail later, in the present embodiment, the ECU 9a sets the opening degree of the throttle valve 2 to the minimum opening degree (control zero opening degree) set to allow idling of the engine 20 at the start of cranking. To control. The control zero opening is an opening that allows the engine 20 to take in air to such an extent that idling is possible, and is different from an opening where the throttle valve 2 is fully closed mechanically. Such a control zero opening degree is an opening degree which is zero in control of the engine 20, and is stored in the memory after being obtained in advance by experiments and simulations. That is, with the control zero opening as zero, the target value and the detection value of the opening of the throttle valve 2 are determined.

  Further, in the present embodiment, the ECU 9a detects that the crank angle first reaches a predetermined reference angle after the start of cranking in the engine start control, and the cylinder provided in the engine 20 based on the detection Before the stroke of one cylinder 21, the second cylinder 22 and the third cylinder 23 is determined, the opening degree of the throttle valve 2 is controlled to be the start target opening degree. The start target opening degree is an opening degree set so that the rotation speed of the engine 20 is stabilized early to the target rotation speed at idling, and is stored in the memory after being obtained in advance by experiments or simulations. Note that it is preferable to change the start target opening degree according to the temperature of the engine 20 (temperature of cooling water) before the start. For this reason, in the present embodiment, a table (target opening degree table) indicating the relationship between the temperature of the cooling water and the start target opening degree is stored in the memory of the ECU 9a.

  Subsequently, an engine start method by the engine control system 1 of the present embodiment will be described with reference to the timing chart of FIG. 2 and the flowchart of FIG. 3. Note that FIG. 2 shows the injection timing of fuel in each injector (the first injector 21a, the second injector 22a, and the third injector 23a), and each ignition coil (the first ignition coil 21b, the second ignition coil 22b, and the third ignition) 5 is a timing chart showing the ignition timing by the coil 23b), the opening degree of the throttle valve 2, the on / off state of the ignition switch 7, and the on / off state of the starter switch 6. FIG. FIG. 3 is a flowchart showing the process flow of the ECU 9a at the time of engine start.

  When the ignition switch 7 is turned on by the occupant, the battery 8 and the engine start control device 9 are energized, and power is supplied from the battery 8 to the ECU 9a and the throttle valve controller 9b. When the ECU 9a is started by being supplied with power from the battery 8, as shown in FIG. 3, the ECU 9a determines whether the engine 20 is stopped (step S1). Here, the ECU 9a determines whether the engine 20 is stopped based on the signal input from the crank angle sensor 25.

  When the ECU 9a determines that the engine 20 is at rest, the ECU 9a outputs a control signal indicating that the opening degree of the throttle valve 2 should be the control zero opening degree (step S2). The control signal indicating the control zero opening degree output from the ECU 9a is input to the throttle valve controller 9b. The throttle valve controller 9 b generates a drive signal for setting the opening degree of the throttle valve 2 to the control zero opening degree from the power of the battery 8 and supplies the generated signal to the valve drive motor 3. As a result, the opening degree of the throttle valve 2 becomes the control zero opening degree TH0.

  Steps S1 and S2 are performed substantially simultaneously after the ignition switch 7 is turned on. Therefore, as shown in FIG. 2, when the ignition switch 7 is turned on, the opening degree of the throttle valve 2 changes from the fully closed state to the control zero opening degree TH0 substantially simultaneously.

  Subsequently, when the starter switch 6 is turned on by the occupant, power is supplied from the battery 8 to the cell motor 4 and cranking is started in which the crankshaft of the engine 20 is rotated by the cell motor 4. When cranking is started and the crankshaft of the engine 20 is rotated by the cell motor 4, a pulse signal is input from the crank angle sensor 25 to the ECU 9a. The ECU 9a determines whether cranking is in progress based on the pulse signal input from the crank angle sensor 25 (step S3).

  When it is determined in step S1 that the engine 20 is not stopping, and when it is determined that cranking is not in progress in step S3, the ECU 9a ends the start control of the engine 20.

  When the ECU 9a determines that cranking is being performed in step S3, the ECU 9a stands by until the first missing tooth is detected by the crank angle sensor 25 (step S4). The ECU 9a determines that the first missing tooth is detected when there is a pulse defect in the pulse signal input from the crank angle sensor 25 and this is the first time after step S3. When the ECU 9a determines that the first missing tooth has been detected, the ECU 9a sets the start target opening degree of the throttle valve 2 (step S5). Here, the ECU 9a sets the start target opening based on the target opening degree table that defines the relationship between the coolant temperature of the engine 20 and the start target opening degree, and the measurement result input from the temperature sensor 24. . Then, when the start target opening degree is set, the ECU 9a outputs a control signal indicating that the opening degree of the throttle valve 2 is to be the start target opening degree (step S6). The control signal indicating the start target opening degree output from the ECU 9a in this manner is input to the throttle valve controller 9b. The throttle valve controller 9 b generates a drive signal for setting the opening degree of the throttle valve 2 to the start target opening degree from the power of the battery 8 and supplies the generated signal to the valve drive motor 3. As a result, the opening degree of the throttle valve 2 becomes the start target opening degree THM.

  As shown in FIG. 2, when the opening degree of the throttle valve 2 reaches the start target opening degree THM, the ECU 9a simultaneously injects fuel from all the injectors (the first injector 21a, the second injector 22a and the third injector 23a) simultaneously. The injection is performed (step S7). It should be noted that, when designing the engine 20, as the number of cylinders increases, it is easy to set one of the cylinders as the intake stroke at all crank angles (360 °). Air can be supplied to any cylinder. In this case, it is possible to supply a large amount of air to the cylinder immediately after a period in which compression loss may occur immediately after the start of cranking, and it is possible to stabilize the engine rotation speed earlier. In the present embodiment, when the first cylinder 21 has a crank angle at the initial stage of the intake stroke, the missing tooth region of the rotor is disposed so as to be within the measurement range of the crank angle sensor 25. . Therefore, by performing simultaneous injection in a short time from the detection of the first missing tooth in step S4, the fuel injected by the simultaneous injection flows into the combustion chamber of the first cylinder 21. Thereafter, as shown in FIG. 2, the ECU 9a supplies electric power to each ignition coil (the first ignition coil 21b, the second ignition coil 22b and the third ignition coil 23b) at a predetermined interval, and Ignite against

  Subsequently, when the ECU 9a determines that cranking is in progress in step S3, the ECU 9a stands by until the second missing tooth is detected by the crank angle sensor 25 (step S8). The ECU 9a determines that the second missing tooth is detected when there is a missing pulse in the pulse signal input from the crank angle sensor 25 and this is the second time after step S3. If the ECU 9a determines that the second missing tooth has been detected, it determines the stroke of each cylinder (step S9). Furthermore, the ECU 9a determines the stroke of each cylinder based on, for example, an input from an intake pressure sensor (not shown). Then, after the detection of the second missing tooth, the ECU 9a repeatedly injects fuel from the injector and supplies electric power to the ignition coil at predetermined timing based on the engine rotational speed, the accelerator opening degree, and the like. In addition, after the engine 20 completely detonates (ignition to the air-fuel mixture) in any of the cylinders, it continues to operate continuously by injecting fuel from the above-described injector and supplying power to the ignition coil.

  According to the engine control system 1 provided with the engine start control device 9 of the present embodiment as described above, it is detected that the crank angle first reaches a predetermined reference angle after the start of cranking (detection of the first missing tooth) After that, the throttle valve 2 is controlled so as to reach the start target opening THM. Therefore, a large amount of air can be prevented from flowing into the cylinders of the engine 20 at the start of cranking. Therefore, during cranking, it is possible to prevent compression loss due to the presence of a large amount of air in the cylinder, and to improve the startability of the engine 20.

  Furthermore, according to the engine control system 1 provided with the engine start control device 9 of the present embodiment, after the crank angle first becomes the reference angle, the throttle valve 2 becomes the start target opening THM before the stroke of the cylinder is determined. Therefore, the engine rotation speed can be raised early, and the engine rotation speed can be stabilized early to the target rotation speed at idling.

  Therefore, according to the engine control system 1 provided with the engine start control device 9 of the present embodiment, when adjusting the opening degree of the throttle valve 2 to the start target opening degree suitable for engine start at the time of engine start, It becomes possible to start the engine 20 more reliably while making it possible to stabilize the number.

  Further, in the engine control system 1 including the engine start control device 9 of the present embodiment, the minimum opening degree (control zero opening degree TH0) in which the opening degree of the throttle valve 2 is set to be idleable at the start of cranking. Control to be Therefore, the air flowing into the cylinder at the start of the cranking can be minimized, and the engine 20 can be more reliably started.

  Further, in the engine control system 1 including the engine start control device 9 of the present embodiment, the crank angle at which at least one cylinder takes an intake stroke is set as the reference angle. Therefore, by detecting the reference angle and setting the throttle valve 2 to the start target opening degree, a large amount of air can be quickly supplied to any of the cylinders. As soon as a period of compression loss may occur immediately after the start of cranking, a large amount of air can be supplied to the cylinder, and the engine speed can be stabilized earlier.

  Further, in the engine control system 1 including the engine start control device 9 of the present embodiment, the opening degree of the throttle valve 2 is set as the start target opening degree THM prior to the simultaneous injection. Therefore, the fuel injected for simultaneous injection can be made to flow into the cylinder together with a large amount of air, and the startability of the engine 20 is improved.

  Although the preferred embodiments of the present invention have been described above with reference to the accompanying drawings, it goes without saying that the present invention is not limited to the above embodiments. The shapes, combinations, and the like of the constituent members shown in the above-described embodiment are merely examples, and various changes can be made based on design requirements and the like without departing from the spirit of the present invention.

  For example, in the above-described embodiment, the configuration in which the reference angle of the crank angle is set to the angle at which the first cylinder 21 takes an intake stroke has been described. However, the present invention is not limited to this. For example, the angle at which the second cylinder 22 and the third cylinder 23 take an intake stroke may be used as the reference angle of the crank angle. In addition, in the case where a configuration in which any cylinder is at the intake stroke at all crank angles is not adopted, it is also possible to set the reference angle of the crank angle to an angle at which neither cylinder is at the intake stroke.

  Further, in the above embodiment, the configuration has been described in which the opening degree of the throttle valve 2 is made the start target opening degree THM substantially simultaneously with detection of the first missing tooth. However, the present invention is not limited to this, and it is detected that the timing of setting the opening degree of the throttle valve 2 to the start target opening degree THM before the determination of the stroke of the cylinder and at the reference angle first. That's fine. For example, on the premise that it is before the timing at which the stroke of the cylinder is determined, the opening degree of the throttle valve 2 may be set as the start target opening degree THM after a predetermined period has elapsed since the first missing tooth was detected.

  Moreover, in the said embodiment, the engine 20 demonstrated the structure provided with three cylinders (The 1st cylinder 21, the 2nd cylinder 22, and the 3rd cylinder 23). However, the present invention is not limited to this, and can also be applied to start a multi-cylinder engine other than a single cylinder or three cylinders.

  DESCRIPTION OF SYMBOLS 1 ...... Engine control system, 2 ...... Throttle valve, 3 ...... Valve drive motor, 4 ...... Cell motor, 5 ...... Relay, 6 ...... Starter switch, 7 ...... Ignition switch, 8 ...... Battery, 9 ...... Engine start control device 9a: ECU 9b: throttle valve controller 20: engine 21: first cylinder 22: second cylinder 23: third cylinder 24: temperature sensor , 25 ...... Crank angle sensor

Claims (5)

An engine start control device that adjusts an opening degree of a throttle valve to a start target opening degree suitable for engine start at the time of engine start,
After the start of cranking, it is detected that the crank angle first reaches a predetermined reference angle, and based on the detection, the opening degree of the throttle valve is set to the start target opening degree before the stroke of the cylinder provided in the engine is determined. An engine start control device characterized by controlling to become.   2. The engine start control device according to claim 1, wherein at the start of cranking, the opening degree of the throttle valve is controlled to be a minimum opening degree set so that the engine can idle.   3. The engine start control system according to claim 1, wherein a crank angle at which at least one of the cylinders takes an intake stroke is the reference angle.   The engine according to any one of claims 1 to 3, wherein the opening degree of the throttle valve is set to the start target opening degree prior to simultaneous injection for simultaneously supplying fuel to a plurality of the cylinders. Start control device. An engine start method for adjusting an opening degree of a throttle valve to a start target opening degree suitable for engine start at the time of engine start,
After the start of cranking, it is detected that the crank angle first reaches a predetermined reference angle, and based on the detection, the opening degree of the throttle valve is set to the start target opening degree before the stroke of the cylinder provided in the engine is determined. An engine start method characterized by having.

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