JP2019044623A - 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 and suppressing the reset of an EUC while enabling a stable engine speed earlier within the realms of possibility.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 with battery power changes a timing for setting the throttle valve 2 at the starting target opening according to battery voltage before cranking start.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. At this time, if the charge level of the battery is low, 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.

  Furthermore, immediately after the start of cranking, the battery voltage drops due to the drive of the cell motor. However, if the charge level of the battery is low at this time, the power supply to the ECU (Engine Control Unit) runs short and the ECU unintentionally It may be reset.

  The present invention has been made in view of the above-mentioned problems, and an engine start control device and an engine start method capable of adjusting the opening degree of the throttle valve to a start target opening degree suitable for engine start at engine start. It is an object of the present invention to more reliably start the engine and to prevent the reset of the EUC while enabling the engine speed to be stabilized early.

  The present invention adopts the following configuration as means for solving the above-mentioned 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 by battery power, and the above-mentioned throttle according to battery voltage before cranking start. A configuration is adopted in which the timing at which the valve reaches the start target opening is changed.

  According to a second aspect of the invention, in the first aspect, the start preparation process for preparing the connected device is performed before the cranking starts, and the throttle valve is controlled according to the battery voltage during the start preparation process. The structure which changes the timing which makes the said starting target opening degree is employ | adopted.

  In a third aspect based on the second aspect, the start check of a fuel pump for supplying fuel to the injector is performed during the start preparation process, and the throttle valve is determined according to the battery voltage after the start of the fuel pump. The structure which changes the timing which makes the said starting target opening degree is employ | adopted.

  A fourth invention according to any one of the first to third inventions, wherein the battery voltage is acquired at a plurality of timings, and the throttle valve is moved to the start target opening based on an average value of the plurality of battery voltages. Adopt a configuration that changes the timing to be taken.

  According to a fifth invention, in any one of the first to fourth inventions, a configuration is adopted in which the timing of setting the throttle valve to the start target opening is delayed as the battery voltage is lower.

  A sixth invention is an engine start method for adjusting the opening degree of a throttle valve to a start target opening degree suitable for engine start at the time of engine start by battery power, and the above throttle valve according to the battery voltage before the start of cranking. The structure which changes the timing which makes the said starting target opening degree is employ | adopted.

  According to the present invention, according to the battery voltage before cranking, the timing for setting the throttle valve to the start target opening is changed. As described above, in the present invention, the timing at which the throttle valve, which has conventionally been fixed, is set to the start target opening degree is made variable by the battery voltage before cranking. Therefore, based on the battery voltage, it is possible to set the throttle valve to the target start opening as early as possible without causing compression loss in the cylinder or resetting in the ECU. 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 speed is stabilized early in the possible range. While enabling this, it is possible to more reliably start the engine and prevent the EUC from being reset.

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 graph which shows the time-sequential change of the battery voltage at the time of engine starting. 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 a fuel and an ignition coil for igniting a mixture containing the 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.

  A fuel pump 30 is connected to the first injector 21a, the second injector 22a, and the third injector 23a. The fuel pump 30 pressurizes the fuel and supplies the boosted fuel to the first injector 21a, the second injector 22a, and the third injector 23a.

  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.

  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) 9 a and a throttle valve controller 9 b which generates a three-phase drive signal from battery power and supplies it to the valve drive motor 3 under the control of the ECU 9 a. 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. Further, as shown in FIG. 1, the ECU 9 a includes a battery voltage detection circuit 9 a 1 for detecting the voltage (battery voltage) of the battery 8.

  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.

  Further, the ECU 9a controls the opening degree of the throttle valve 2 in the control of starting the engine 20 from the stop state (engine start control). In the present embodiment, the ECU 9a sets a timing at which the throttle valve 2 is set to the target opening degree of opening in accordance with the battery voltage before the start of cranking in the engine start control. 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.

  Further, the ECU 9a stores the minimum opening (control zero opening) of the throttle valve 2 at which the engine 20 can idle. 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.

  Furthermore, the ECU 9a stores a first battery voltage threshold V1 and a second battery voltage threshold V2 for determining the timing of setting the throttle valve 2 to the target opening degree. The first battery voltage threshold V1 and the second battery voltage threshold V2 are stored in the memory after being obtained in advance by experiment or simulation. The first battery voltage threshold V1 is a threshold close to the voltage value when the battery 8 is fully charged, and indicates that sufficient electric power can be supplied to the cell motor 4 at the time of cranking when the battery voltage exceeds this. Here, "sufficient electric power can be supplied to the cell motor 4" means that even if engine friction increases due to low temperature and so on and the throttle valve 2 has a target start opening degree at the start of cranking, the crankshaft It means that electric power capable of generating a torque for rotating the electric motor is supplied to the cell motor 4. That is, by applying a voltage exceeding the first battery voltage threshold V1 to the cell motor 4, engine friction increases due to a low temperature and the like, and the throttle valve 2 has a start target opening at the start of cranking, Also, torque for rotating the crankshaft can be generated by the cell motor 4.

  The second battery voltage threshold V2 is a threshold which is lower than the first battery voltage threshold V1 and which indicates that the cell motor 4 may be supplied with minimal power at the time of cranking when the battery voltage is lower than the first battery voltage threshold V1. Here, "only minimum power can be supplied to the cell motor 4" means that power can be supplied to the cell motor 4 for which the torque for rotating the crankshaft can not be obtained unless the throttle valve 2 has a control zero opening at the start of cranking It means that. That is, when a voltage below the second battery voltage threshold V2 is applied to the cell motor 4, there is a possibility that the cell motor 4 can not generate torque for rotating the crankshaft unless the throttle valve 2 is at the control zero opening.

  In the present embodiment, the ECU 9a detects and stores the battery voltage by the battery voltage detection circuit 9a1 before the start of cranking, and changes the timing for setting the throttle valve 2 to the target opening degree based on the stored battery voltage Do. For example, the ECU 9a acquires the battery voltage a plurality of times before the start of cranking, and when the average value is equal to or more than the first battery voltage threshold V1, the cranking start timing for setting the throttle valve 2 to the start target opening degree Immediately after. Further, for example, when the average value is lower than the first battery voltage threshold V1 and equal to or higher than the second battery voltage threshold V2, the ECU 9a sets the timing at which the throttle valve 2 is to be the target opening degree for the crank angle sensor 25. The timing when the first missing tooth is detected by Further, for example, when the average value is lower than the second battery voltage threshold V2, the ECU 9a sets the timing for setting the throttle valve 2 to the start target opening degree after the complete explosion (ignition to air-fuel mixture). That is, the ECU 9a delays the timing for setting the throttle valve 2 to the target opening degree as the battery voltage is lower.

  Also, when the ignition switch 7 is turned on and the battery 8 is supplied with power, the ECU 9a first performs its own startup process. Subsequently, the ECU 9a performs start preparation processing for preparing a device (for example, the fuel pump 30) connected to the ECU 9a after completion of the start processing. Further, in the present embodiment, the ECU 9a detects the battery voltage in parallel with the start preparation process. At this time, it is preferable that the detection of the battery voltage be after the start of the fuel pump 30. The driving of the fuel pump 30 consumes most battery power in the start preparation process. Therefore, by detecting the battery voltage after the fuel pump 30 is started, it is possible to more accurately determine the torque that can be generated by the cell motor 4 in the subsequent cranking.

  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, the graph of FIG. 3 and the flowchart of FIG. 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 graph showing time-series changes in battery voltage at engine start. Moreover, FIG. 4 is a flowchart which shows the processing flow of ECU9a at the time of engine starting.

  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. 4, 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.

  Then, when the ECU 9a determines that the engine 20 is stopped, the ECU 9a performs start preparation processing for preparing a device connected to itself. In the present embodiment, the ECU 9a adjusts the opening degree of the throttle valve 2 to the control zero opening degree in the start preparation process (step S2), and checks the start of the fuel pump 30 (step S3). A battery voltage acquisition process (step S4) and a battery voltage average value calculation process (step S5) are performed. The order of step S2 and step S3 may be reversed.

  In step S2, the ECU 9a outputs a control signal indicating that the opening degree of the throttle valve 2 should be the control zero opening degree. 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, as shown in FIG. 2, the opening degree of the throttle valve 2 becomes the control zero opening degree TH0.

  In step S3, the ECU 9a monitors, for example, the state of power supply to the fuel pump 30, and determines whether or not the fuel pump 30 is normally started based on whether or not the power supply to the fuel pump 30 is normally performed. It waits until the fuel pump 30 is started. When the ECU 9a determines in step S3 that the fuel pump 30 has been started, the ECU 9a detects and acquires the battery voltage by the battery voltage detection circuit 9a1 (step S4). That is, in the present embodiment, the ECU 9a acquires the battery voltage after the fuel pump 30 is started. Since power is required to start the fuel pump 30, the battery voltage drops after the fuel pump 30 is started during the start preparation process, as shown in FIG. In the present embodiment, the ECU 9a acquires the battery voltage after the fuel pump 30 is started and the battery voltage drops.

  In addition, in step S3, the ECU 9a changes the timing and acquires the battery voltage a plurality of times. Then, the ECU 9a calculates an average value of the plurality of battery voltages (battery voltage average value VB) (step S5). Subsequently, the ECU 9a stands by until the starter switch 6 is turned on (step S6). The ECU 9a may keep updating the battery voltage average value VB until the starter switch 6 is turned on.

  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. When the ECU 9a determines that the starter switch 6 is turned on in step S6, it determines whether cranking is in progress based on a pulse signal input from the crank angle sensor 25 (step S7).

  When it is determined in step S1 that the engine 20 is not stopping, or when it is determined that cranking is not in progress in step S7, the ECU 9a ends the start control of the engine 20.

  If it is determined in step S7 that cranking is in progress, the ECU 9a determines whether the battery voltage average value VB is greater than or equal to the first battery voltage threshold V1 (step S8). If the ECU 9a determines that the battery voltage average value VB is greater than or equal to the first battery voltage threshold V1, the ECU 9a sets a start target opening degree of the throttle valve 2 (step S9). 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 made the start target opening degree (step S10). 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. That is, in the present embodiment, as shown by the throttle valve opening degree (a) in FIG. 2, the ECU 9a immediately after starting cranking when the battery voltage average value VB is the first battery voltage threshold V1 or more. The opening degree of the throttle valve 2 is made the start target opening degree THM.

  If the ECU 9a determines that the battery voltage average value VB is lower than the first battery voltage threshold V1 in step S8, the ECU 9a determines whether the battery voltage average value VB is equal to or higher than the second battery voltage threshold V2 (step S11). If the ECU 9a determines that the battery voltage average value VB is equal to or greater than the second battery voltage threshold V2, the ECU 9a stands by until the first missing tooth is detected by the crank angle sensor 25 (step S12). 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 S7. When the ECU 9a determines that the first missing tooth has been detected, the ECU 9a proceeds to step S9. That is, in the present embodiment, as shown by the throttle valve opening degree (b) in FIG. 2, the ECU 9a determines that the battery voltage average value VB is lower than the first battery voltage threshold V1 and not lower than the second battery voltage threshold V2. It is waited to start the cranking and set the opening degree of the throttle valve 2 as the start target opening degree THM until the first missing tooth is detected.

  When step S10 is completed, the ECU 9a stands by until the second missing tooth is detected by the crank angle sensor 25 (step S13). If there is a missing pulse in the pulse signal input from the crank angle sensor 25 and this is the second time after step S7, it is determined that the second missing tooth is detected. If the ECU 9a determines that the second missing tooth has been detected, it determines the stroke of each cylinder (step S14). 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.

  If the ECU 9a determines in step S11 that the battery voltage average value VB is lower than the second battery voltage threshold V2, the ECU 9a stands by until the second missing tooth is detected by the crank angle sensor 25 (step S15). Furthermore, the ECU 9a stands by until complete explosion, which is a state in which the air-fuel mixture is ignited by any of the cylinders (step S16). Here, the ECU 9a determines based on the pulse interval of the pulse signal input from the crank angle sensor 25 whether or not the complete explosion has occurred.

  If the ECU 9a determines in step S16 that complete explosion has occurred, it determines the stroke of each cylinder (step S17), and then sets the start target opening THM of the throttle valve 2 (step S18). A control signal indicating that the opening degree of the vehicle is set to the start target opening degree THM is output (step S19). Step S17 is the same process as step S14 described above, step S18 is the same process as step S9 described above, and step S19 is the same process as step S10 described above. That is, in the present embodiment, as shown by the throttle valve opening degree (c) in FIG. 2, the ECU 9a completely detonates in any cylinder when the battery voltage average value VB is lower than the second battery voltage threshold V2. It is waited until the opening degree of the throttle valve 2 becomes the start target opening degree THM.

  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.

  According to the engine control system 1 provided with the engine start control device 9 of the present embodiment as described above, the timing at which the throttle valve 2 is made the start target opening THM is changed according to the battery voltage before cranking. As described above, in the engine control system 1 including the engine start control device 9 of the present embodiment, the timing at which the conventionally fixed throttle valve 2 is used as the start target opening THM is variable according to the battery voltage before cranking. It is assumed. Therefore, based on the battery voltage, it is possible to set the throttle valve 2 to the start target opening degree THM as early as possible without causing compression loss in the cylinder and reset in the ECU. Therefore, according to the engine control system 1 including the engine start control device 9 of the present embodiment, the engine rotation speed can be stabilized early in the possible range, and the engine can be started more reliably and the reset of the EUC is suppressed more reliably. It becomes possible.

  Further, in the engine control system 1 provided with the engine start control device 9 of the present embodiment, the start preparation process for preparing the connected device is performed before the start of cranking, and according to the battery voltage in the start preparation process. The timing at which the throttle valve 2 is set to the start target opening degree THM is changed. For this reason, it is possible to change the timing at which the throttle valve 2 is set to the start target opening degree THM in consideration of the fluctuation of the battery voltage during the start preparation process.

  Further, in the engine control system 1 including the engine start control device 9 of the present embodiment, the start check of the fuel pump 30 is performed during the start preparation process, and the throttle valve 2 is adjusted according to the battery voltage after the start of the fuel pump 30. The timing at which the start target opening degree THM is set is changed. Therefore, by detecting the battery voltage after the start of the fuel pump 30 that consumes the most battery power in the start preparation process, it is possible to more accurately determine the torque that can be generated by the cell motor 4 in the subsequent cranking.

  Further, in the engine control system 1 including the engine start control device 9 of the present embodiment, the battery voltage is acquired at a plurality of timings, and the throttle valve is obtained based on the average value of the plurality of battery voltages (battery voltage average value VB). The timing at which 2 is set as the start target opening THM is changed. Therefore, it is possible to more accurately determine the torque that can be generated by the cell motor 4 by excluding the influence of the local fluctuation of the battery voltage.

  Further, in the engine control system 1 including the engine start control device 9 of the present embodiment, the timing of setting the throttle valve 2 to the start target opening degree THM is delayed as the battery voltage is lower. The torque which needs to be generated by the cell motor 4 at the time of engine start decreases with the increase of the engine speed. Therefore, the compression loss in the cylinder can be more reliably prevented by delaying the timing of setting the throttle valve 2 to the start target opening degree THM as the battery voltage is lower.

  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 embodiment, in order to set the battery voltage average value VB to be equal to or greater than the first battery voltage threshold V1, the opening degree of the throttle valve 2 is set as the start target opening degree THM immediately after cranking is started. explained. However, the present invention is not limited to this, and for the battery voltage average value VB to be the first battery voltage threshold V1 or more, the opening degree of the throttle valve 2 is set to the start target opening degree THM before cranking starts. It is also possible to adopt the following configuration.

  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, 30 ... fuel pump

Claims (6)

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 by battery power,
An engine start control device, comprising: changing a timing of setting the throttle valve to the start target opening according to a battery voltage before the start of cranking. Before start of the cranking, start preparation processing for preparing connected devices;
The engine start control device according to claim 1, wherein the timing for setting the throttle valve to the start target opening degree is changed according to the battery voltage in the start preparation process.   The start confirmation of a fuel pump for supplying fuel to the injector is performed during the start preparation process, and the timing of setting the throttle valve to the start target opening degree is changed according to the battery voltage after the start of the fuel pump. The engine start control device according to claim 2, characterized in that:   4. The battery voltage is acquired at a plurality of timings, and the timing at which the throttle valve is set to the target opening degree for opening is changed based on an average value of the plurality of battery voltages. The engine start control device according to one item.   The engine start control device according to any one of claims 1 to 4, wherein the timing of setting the throttle valve to the start target opening degree is delayed as the battery voltage is lower. 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 by battery power,
An engine start method, comprising: changing a timing at which the throttle valve is set to the start target opening according to a battery voltage before the start of cranking.

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