JP2019138168A - Engine start control device and engine start control method - Google Patents

Abstract

To further surely start an engine while stabilizing an engine rotation number in an early stage, in an engine start control device and an engine start control method for adjusting an opening of a throttle valve to a start target opening which is suitable for a start of an engine at the start of the engine.SOLUTION: An engine start control device 9 for adjusting an opening of a throttle valve 2 to a start target opening which is suitable for a start of an engine at the start of the engine controls the opening of the throttle valve 2 so as to reach the start target opening on the basis of timing after a start of cranking, and at which a time interval of adjacent crank pulses becomes a preset adjustment start interval.SELECTED DRAWING: Figure 1

Description

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

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

International Publication No. 2012/091014 Japanese Patent Laid-Open No. 2000-257572

  By the way, in order to stabilize the engine speed at an early stage, it is preferable to set the opening of the throttle valve as the starting target opening as early as possible. For this reason, it can be considered that the opening degree of the throttle valve is set as the starting target opening degree when the ignition switch is turned on.

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

  On the other hand, in Patent Document 2, the opening degree of the throttle valve is set as the starting opening degree based on the engine speed. However, the engine speed cannot be calculated unless the crankshaft of the engine is rotated once because the time interval of the plurality of crank pulses is calculated as an average value. For this reason, when the opening degree of the throttle valve is set as the starting target opening degree based on the engine speed, it is necessary to wait for calculation of the engine speed, and the opening degree of the throttle valve may be set as the starting target opening degree at an early stage. Can not.

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

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

  A first invention is an engine start control device that adjusts the opening degree of a throttle valve to a start target opening degree suitable for engine start at the time of engine start, and the time interval between adjacent crank pulses is set in advance after cranking is started. A configuration is adopted in which the opening degree of the slot valve is controlled so as to become the starting target opening degree based on a timing when a predetermined adjustment start interval is reached.

  According to a second aspect, in the first aspect, the adjustment start interval is set based on a time interval of the crank pulse realized by complete explosion in at least one cylinder included in the engine. Adopt the configuration.

  According to a third invention, in the first or second invention, a configuration is adopted in which the opening degree of the slot valve is controlled to become the starting target opening degree after the stroke of a cylinder provided in the engine is determined.

  A fourth invention is an engine start control method for adjusting a throttle valve opening to a start target opening suitable for engine start at the time of engine start, wherein the time interval between adjacent crank pulses is set in advance after cranking is started. A configuration is adopted in which the opening degree of the slot valve is set as the starting target opening degree based on a timing at which a predetermined adjustment start interval is reached.

  According to the present invention, the throttle valve is controlled to reach the start target opening degree at the timing after the cranking is started and the time interval of the crank pulse becomes the predetermined adjustment start interval. For this reason, at the start of cranking, a large amount of air can be prevented from flowing into the cylinder of the engine, and the engine startability can be improved. In addition, according to the present invention, since the engine speed is not calculated, the throttle valve can be set to the target opening at an early stage within a range in which the startability does not deteriorate, and the engine speed can be stabilized early. Can be made. Therefore, according to the present invention, in the engine start control device and the engine start control method for adjusting the opening degree of the throttle valve to the start target opening degree suitable for engine start at the time of engine start, the engine speed can be stabilized at an early stage. Thus, the engine can be started more reliably.

1 is a block diagram showing a schematic configuration of an engine control system including a function as an engine start control device of an embodiment of the present invention. 4 is a timing chart showing a crank pulse signal, fuel injection timing in an injector, ignition timing by an ignition coil, throttle valve opening, ignition switch on / off state, and starter switch on / off state. It is a flowchart which shows the process flow at the time of engine start of ECU with which the engine control system including the function as an engine start control apparatus of one Embodiment of this invention is provided.

  Hereinafter, an embodiment of an engine start control device and an engine start control method according to the present invention will be described with reference to the drawings.

  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 rotation speed of the 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 an air-fuel mixture containing fuel. In the following description, the injector and the ignition coil installed in the first cylinder 21 are referred to as the first injector 21a and the first ignition coil 21b, and the injector and the ignition coil installed in the second cylinder 22 as necessary. Are called the second injector 22a and the second ignition coil 22b, and the injector and the ignition coil installed in the third cylinder 23 are called the third injector 23a and the third ignition coil 23b. In addition, 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 23b 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 air, an explosion stroke for burning air and fuel, and a combustion An exhaust stroke for exhausting gas from the cylinder is sequentially performed. The same stroke in each cylinder starts with a different crank angle. 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, a temperature sensor 24 and a crank angle sensor 25 are installed for the engine 20. 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 crank pulse signal indicating the passage of teeth of a rotor that is fixed to the crankshaft of the engine 20 and rotated together with the crankshaft. The time interval between adjacent crank pulses in such a crank pulse signal changes according to the rotational speed of the engine 20.

  As shown in FIG. 1, the engine control system 1 of this 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, a battery 8, And an engine start control device 9.

  The throttle valve 2 is a valve for adjusting the intake amount of the engine 20. The throttle valve 2 includes a disc-like valve body whose posture can be changed, and adjusts the amount of air passing through (ie, the intake amount of the engine 20) by changing the inclination angle of the valve body with respect to the flow direction. . The valve drive motor 3 is, for example, a three-phase brushless motor, and an 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 according to a three-phase drive signal input from a throttle valve controller 9b described later of the engine start control device 9.

  The cell motor 4 is a DC motor that generates rotational power using 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 via 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. The When such a cell motor 4 is connected to the battery 8, it 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.

  The relay 5 is arranged 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 a switch that is installed, for example, at a handle portion of a motorcycle, and that allows the relay 5 to be energized while being pressed by an occupant. The ignition switch 7 is a switch connected by inserting and rotating a key (not shown), for example. 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 described later of the engine start control device 9. In addition, when the ignition switch 7 is turned on, the battery motor 8 can be supplied with power to the cell motor 4 via the relay 5. The battery 8 is connected to the engine start control device 9 via the ignition switch 7. In addition, 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 comprehensively 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. For example, the ECU 9a calculates the opening degree of the throttle valve 2 based on inputs from the temperature sensor 24, the crank angle sensor 25, and the like, and sends a control signal indicating the calculated opening degree of the throttle valve 2 to the throttle valve controller. Input to 9b. 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, and the third ignition coil 23b based on inputs from the temperature sensor 24, the crank angle sensor 25, and the like. Also do. The ECU 9a performs not only engine start control but also operation control of the engine 20 after start.

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

  Further, in the present embodiment, the ECU 9a sets an adjustment start interval (hereinafter referred to as adjustment start interval ta) in which a time interval between adjacent crank pulses (hereinafter referred to as pulse interval tp) is preset after cranking is started in engine start control. Based on this detection, the opening of the throttle valve 2 is controlled so as to become the starting target opening. This starting target opening is an opening that is set so that the rotational speed of the engine 20 stabilizes at an early stage to the target rotational speed in idling, and is obtained in advance by experiments and simulations and stored in the memory. The starting target opening is preferably changed according to the temperature of the engine 20 (cooling water temperature) before starting. 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 starting target opening degree is stored in the memory of the ECU 9a.

  Further, the ECU 9a stores an adjustment start interval ta that serves as a reference for timing to start changing the throttle valve opening from the control zero opening to the start target opening in the engine start control. The adjustment start interval ta is realized in advance by performing an explosion (ignition of the air-fuel mixture) in the cylinders (the first cylinder 21, the second cylinder 22, and the third cylinder 23) included in the engine 20 through experiments and simulations. It is set based on the time interval of the crank pulse. In other words, in the starting control of the engine 20, the air-fuel mixture in the cylinders (the first cylinder 21, the second cylinder 22, and the third cylinder 23) included in the engine 20 is obtained by setting the pulse interval tp of the crank pulse signal to the adjustment start interval ta. It can be confirmed that is ignited. Therefore, in the start control of the engine 20, when the pulse interval tp of the crank pulse signal becomes the adjustment start interval ta, a large amount of air flows into at least the cylinders (the first cylinder 21, the second cylinder 22, and the third cylinder 23). However, engine power is obtained to such an extent that no compression loss occurs.

  Next, an engine start control 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. 2 shows a crank pulse signal, fuel injection timing in each injector (first injector 21a, second injector 22a, and third injector 23a), and each ignition coil (first ignition coil 21b, second ignition coil). 22b and the third ignition coil 23b) are timing charts showing the ignition timing, 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. 3 is a flowchart showing a processing flow of the ECU 9a when starting the engine.

  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 activated by being supplied with power from the battery 8, as shown in FIG. 3, the ECU 9a determines whether or not the engine 20 is stopped (step S1). Here, the ECU 9a determines whether or not the engine 20 is stopped based on a signal input from the crank angle sensor 25.

  When it is determined that the engine 20 is stopped, the ECU 9a outputs a control signal indicating that the opening degree of the throttle valve 2 is set to the control zero opening degree (step S2). A control signal indicating that the control zero opening is 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 of the throttle valve 2 to the control zero opening from the electric power of the battery 8 and supplies it to the valve drive motor 3. As a result, the opening degree of the throttle valve 2 becomes the control zero opening degree TH0.

  Note that step S1 and step S2 are performed substantially simultaneously after the ignition switch 7 is turned on. For this reason, 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 an occupant, electric power is supplied from the battery 8 to the cell motor 4, and cranking in which the crank shaft of the engine 20 is rotated by the cell motor 4 is started. When cranking is started and the crankshaft of the engine 20 is rotated by the cell motor 4, a crank pulse signal is input from the crank angle sensor 25 to the ECU 9a. The ECU 9a determines whether cranking is being performed based on the crank pulse signal input from the crank angle sensor 25 (step S3).

  If it is determined in step S1 that the engine 20 is not stopped, or if it is determined that cranking is not being performed in step S3, the ECU 9a ends the start control of the engine 20. If the ECU 9a determines that cranking is being performed in step S3, the ECU 9a performs simultaneous injection in which fuel is simultaneously injected from all of the injectors (the first injector 21a, the second injector 22a, and the third injector 23a) ( Step S4). Thereafter, as shown in FIG. 2, the ECU 9a supplies 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 the air-fuel mixture in each cylinder. Ignite against. Further, the ECU 9a determines the stroke of each cylinder (step S5). Here, the ECU 9a determines the stroke of each cylinder based on, for example, an input from an unillustrated intake pressure sensor.

  Subsequently, the ECU 9a waits until the pulse interval tp becomes equal to or less than the adjustment start interval ta (step S6). The ECU 9a obtains a time interval between adjacent crank pulses from the crank pulse signal input from the crank angle sensor 25, and sets this as a pulse interval tp. Further, the ECU 9a compares the pulse interval tp with the adjustment start interval ta stored in advance, and determines whether or not the pulse interval tp is equal to or less than the adjustment start interval ta.

  When the pulse interval tp becomes equal to or shorter than the adjustment start interval ta in step S6, the ECU 9a sets a target opening for starting the throttle valve 2 (step S7). Here, the ECU 9a sets the start target opening based on the target opening table that defines the relationship between the coolant temperature of the engine 20 and the start target opening, and the measurement result input from the temperature sensor 24. . When the start target opening is set, the ECU 9a outputs a control signal indicating that the opening of the throttle valve 2 is set to the start target opening (step S8). Thus, the control signal indicating the start target 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 starting target opening degree from the electric power of the battery 8 and supplies it to the valve drive motor 3. As a result, the opening degree of the throttle valve 2 becomes the starting target opening degree THM.

  As shown in FIG. 2, when the opening of the throttle valve 2 reaches the start target opening THM, the operation of the engine 20 is continuously continued by the fuel injection from the injector and the power supply to the ignition coil.

  According to the engine control system 1 including the engine start control device 9 of the present embodiment as described above, the throttle valve 2 is operated after the cranking starts and at the timing when the pulse interval tp becomes a predetermined adjustment start interval ta. The starting target opening degree THM is controlled.

  Therefore, according to the engine control system 1 including the engine start control device 9 of the present embodiment, a large number of cylinders of the engine 20 (the first cylinder 21, the second cylinder 22, and the third cylinder 23) at the start of cranking. Air can be prevented from flowing into the engine 20 and the startability of the engine 20 can be improved. Further, according to the engine control system 1 including the engine start control device 9 of the present embodiment, since the rotation speed of the engine 20 is not calculated, the throttle valve 2 can be started as early as possible within a range where startability does not deteriorate. The opening degree THM can be set, and the engine speed can be stabilized at an early stage.

  Therefore, according to the engine control system 1 including the engine start control device 9 of the present embodiment, the engine start control device and the engine that adjust the opening of the throttle valve 2 to the start target opening THM suitable for engine start when the engine is started. This is a start control method, and it is possible to start the engine 20 more reliably while stabilizing the engine speed at an early stage.

  Further, in the engine start control device 9 of the present embodiment, the adjustment start interval ta is completed in the cylinders (the first cylinder 21, the second cylinder 22, and the third cylinder 23) included in the engine 20 through experiments and simulations in advance. It is set based on the time interval of the crank pulse realized by (igniting the air-fuel mixture). Therefore, the throttle valve 2 can be set to the start target opening THM after waiting for the complete explosion in the cylinders (the first cylinder 21, the second cylinder 22, and the third cylinder 23), and the engine 20 is started more reliably. It becomes possible.

  Further, in the engine start control device 9 of the present embodiment, the opening of the slot valve 2 is determined as the start target opening after the strokes of the cylinders (the first cylinder 21, the second cylinder 22, and the third cylinder 23) included in the engine 20 are determined. It is controlled to be THM. That is, the throttle valve 2 is opened after the stroke is determined so that the fuel injection amount and the ignition timing can be appropriately controlled. For this reason, in confirming the stroke, the influence of the rotation of the throttle valve 2 can be avoided, and the engine 20 can be started more reliably.

  As mentioned above, although preferred embodiment of this invention was described referring an accompanying drawing, it cannot be overemphasized that this invention is not limited to the said embodiment. Various shapes, combinations, and the like of the constituent members shown in the above-described embodiments are examples, and various modifications can be made based on design requirements and the like without departing from the spirit of the present invention.

  For example, in the above embodiment, the complete explosion in the cylinders (first cylinder 21, second cylinder 22, and third cylinder 23) and the stroke determination of the cylinders (first cylinder 21, second cylinder 22, and third cylinder 23) are determined. The configuration in which the opening degree of the throttle valve 2 is used as the starting target opening degree was later described. However, the present invention is not limited to this, and the complete explosion in the cylinders (first cylinder 21, second cylinder 22 and third cylinder 23) or cylinders (first cylinder 21, second cylinder 22 and third cylinder). The configuration in which the opening degree of the throttle valve 2 is set as the starting target opening degree before the stroke determination in 23) is not excluded.

  In the above-described embodiment, the configuration in which the engine 20 includes three cylinders (the first cylinder 21, the second cylinder 22, and the third cylinder 23) has been described. 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 (4)

An engine start control device that adjusts the opening degree of a throttle valve to a start target opening degree suitable for engine start at the time of engine start,
The opening degree of the slot valve is controlled to become the target opening degree of opening based on the timing after the cranking starts and the time interval between adjacent crank pulses becomes a predetermined adjustment starting interval. An engine start control device.   2. The engine start control device according to claim 1, wherein the adjustment start interval is set based on a time interval of the crank pulse realized by complete explosion in at least one cylinder included in the engine. .   3. The engine start control device according to claim 1, wherein the opening degree of the slot valve is controlled so as to become the start target opening degree after the stroke of a cylinder included in the engine is determined. An engine start control method for adjusting a throttle valve opening to a start target opening suitable for engine start at the time of engine start,
An engine start control characterized in that the opening degree of the slot valve is set as the start target opening degree based on the timing at which the time interval between adjacent crank pulses becomes a predetermined adjustment start interval after cranking is started. Method.

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