JP2019044624A - 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 changes a timing for setting the throttle valve 2 at the starting target opening on the basis of a maximum value for a pulse time interval of crank angle sensor output signals during a time from cranking start to the supply of fuel to an engine 20.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.

  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 it is a crank between the start of cranking and fuel supply to the engine A configuration is adopted in which the timing for setting the throttle valve to the start target opening degree is changed based on the maximum value of the pulse time interval of the angle sensor output signal.

  According to a second aspect of the present invention, in the first aspect, a difference between the minimum value of the pulse time interval of the crank angle sensor output signal input from the start of cranking to the supply of fuel to the engine and the maximum value Alternatively, a configuration is adopted in which the timing at which the throttle valve is set to the start target opening degree is changed based on the ratio.

  According to a third invention, in the first invention, the timing of changing the throttle valve to the start target opening is changed based on a difference or a ratio between a preset threshold value and the maximum value. adopt.

  According to a fourth invention, in any one of the first to third inventions, the timing of setting the throttle valve to the start target opening is delayed as the maximum value is larger.

  According to a fifth invention, in any one of the first to fourth inventions, a configuration is provided in which a masking period is provided for a predetermined period from the start of the cranking.

  A sixth 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, which is a crank angle between the start of cranking and fuel supply to the engine A configuration is adopted in which the timing of setting the throttle valve to the start target opening degree is changed based on the maximum value of the pulse time interval of the sensor output signal.

  According to the present invention, based on the maximum value of the pulse time interval of the crank angle sensor output signal from the start of cranking to the supply of fuel to the engine, the timing for setting the throttle valve to the start target opening is changed. The maximum value of the pulse time interval changes due to the effects of compression loss and engine friction in the cylinders of the engine. Therefore, according to the present invention, it is possible to adjust the timing for setting the throttle valve to the target opening degree of opening, taking into consideration compression loss and engine friction in the cylinders of the engine. 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 a crank angle sensor output, an injection timing of fuel in an injector, an ignition timing by an ignition coil, an opening of a throttle valve, an on / off state of an ignition switch, and an 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 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.

  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.

  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.

  In the present embodiment, fuel is supplied to each cylinder of the engine 20 after the crank angle sensor 25 detects the first missing tooth (first missing tooth) of the rotor from the start of cranking. That is, in the present embodiment, the engine 20 is rotated only by the power from the cell motor 4 before the first missing tooth is detected from the start of cranking. In such a state, the engine speed increases when any of the cylinders is in the intake stroke or when none of the cylinders are in the compression stroke, and the engine speed is decreased when any of the cylinders is in the compression stroke. Do. That is, before the first missing tooth is detected from the start of cranking, the number of revolutions of the engine 20 greatly fluctuates. Such a reduction in engine speed during cranking is caused by the compression resistance of air present in the cylinder in the compression stroke. Also, engine friction is one of the causes of engine speed reduction during cranking.

  Here, when the torque of the cell motor 4 is not sufficient and small, the reduction range of the engine speed during cranking becomes large as compared with the case where the torque of the cell motor 4 is sufficiently large. That is, due to the difference in the torque of the cell motor 4, the minimum value of the engine speed during cranking largely fluctuates. On the other hand, the maximum value of the engine rotational speed during cranking does not fluctuate largely due to the difference in the torque of the cell motor 4 because no cylinder is in the compression stroke, for example. Therefore, the difference between the maximum value of the engine rotational speed during cranking and the minimum value of the engine rotational speed during cranking changes with the torque of the cell motor 4 and is small when the torque of the cell motor 4 is relatively large. When the torque of the cell motor 4 is relatively small, it becomes large.

  Therefore, in the present embodiment, the ECU 9a sets the maximum value (hereinafter referred to as the maximum) of the pulse time interval of the pulse signal (crank angle sensor output signal) output from the crank angle sensor 25 until the first missing tooth is detected. The pulse time interval Tmax) is stored. Further, the ECU 9a determines the minimum value of the pulse time interval of the pulse signal output from the crank angle sensor 25 (hereinafter referred to as the minimum) from the start of cranking to the first detection of a missing tooth in the rotor by the crank angle sensor 25. The pulse time interval Tmin) is stored. Further, the ECU 9a obtains a difference ΔT between the maximum pulse time interval Tmax and the minimum pulse time interval Tmin, and changes the timing for setting the throttle valve to the target start opening degree based on the difference ΔT.

  More specifically, the ECU 9a stores a reference pulse time interval T1 to be compared with the difference ΔT. The reference pulse time interval T1 is a threshold value indicating that the minimum torque can be generated in the cell motor 4 when the difference ΔT is equal to or more than this value until the first missing tooth is detected. Here, "only a minimum torque can be generated in the cell motor 4" means that the crankshaft can not be rotated unless the throttle valve 2 has a control zero opening. That is, when the difference ΔT is equal to or greater than the reference pulse time interval T1, there is a possibility that the crankshaft can not be rotated unless the throttle valve 2 is at the control zero opening degree.

  As described above, in the present embodiment, the ECU 9a changes the timing for setting the throttle valve to the start target opening degree based on the difference ΔT between the maximum pulse time interval Tmax and the minimum pulse time interval Tmin. For example, when the difference ΔT is smaller than the reference pulse time interval T1, the ECU 9a sets the timing for setting the throttle valve 2 to the target opening degree immediately after the comparison of the difference ΔT with the reference pulse time interval T1. Further, for example, when the difference ΔT is equal to or more than the reference pulse time interval T1, the ECU 9a sets the timing for setting the throttle valve 2 to the 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 difference ΔT increases.

  Immediately after the start of cranking, the engine speed is extremely low due to inertia. Therefore, it is preferable to obtain the maximum pulse time interval Tmax after the engine speed has increased to some extent. For this reason, in the present embodiment, the ECU 9a does not obtain the maximum pulse time interval Tmax and the minimum pulse time interval Tmin for calculating the difference ΔT, with a fixed period from the start of cranking as the masking period. That is, in the present embodiment, a masking period of a fixed period from the start of cranking is provided. The masking period is canceled, for example, when a predetermined period elapses or when the engine speed increases from the start of cranking to a predetermined speed.

  Subsequently, with reference to the timing chart of FIG. 2 and the flowchart of FIG. 3, an engine start method by the engine control system 1 of the present embodiment will be described. 2 shows the output signal of the crank angle sensor 25 (crank angle sensor output), 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 ( Timing chart showing the ignition timing by the first ignition coil 21b, the second ignition coil 22b and the third ignition 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. It is. 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.

  Then, 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 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, as shown in FIG. 2, the opening degree of the throttle valve 2 becomes the control zero opening degree TH0.

  Subsequently, the ECU 9a stands by until cranking is started (step S3). 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. Based on the pulse signal input from the crank angle sensor 25, it is determined whether cranking has started.

  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 the ECU 9a determines that the cranking has been started in step S3, the ECU 9a stands by until the masking period elapses (step S4). When the masking period has elapsed, the ECU 9a performs acquisition of the minimum pulse time interval Tmin (step S5) and acquisition of the maximum pulse time interval Tmax (step S6). As shown in FIG. 2, the engine speed (pulse time interval) until the first missing tooth largely fluctuates. Therefore, the ECU 9a repeatedly obtains the minimum pulse time interval Tmin and the maximum pulse time interval Tmax until it determines that the first missing tooth is detected after the masking period (step S7). The ECU 9a updates and stores the minimum pulse time interval Tmin when the minimum pulse time interval Tmin acquired after the second time is smaller than the currently stored minimum pulse time interval Tmin. Further, the ECU 9a updates and stores the maximum pulse time interval Tmax, when the maximum pulse time interval Tmax acquired after the second time is larger than the currently stored maximum pulse time interval Tmax.

  If it is determined in step S7 that the first missing tooth is detected, the ECU 9a performs simultaneous injection in which fuel is simultaneously injected from all the injectors (the first injector 21a, the second injector 22a, and the third injector 23a) after step S9. The difference ΔT between the stored maximum pulse time interval Tmax and the minimum pulse time interval Tmin is calculated (step S8), and it is determined whether the difference ΔT is equal to or greater than the reference pulse time interval T1 (step S9). If the ECU 9a determines that the difference ΔT is not the reference pulse time interval T1 or more, it sets the start target opening degree of the throttle valve 2 (step S10). 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 S11). 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, when the difference ΔT is not equal to or longer than the reference pulse time interval T1, the ECU 9a sets the opening degree of the throttle valve 2 as the start target opening degree THM immediately after step S9. As a result, as shown in the throttle valve opening degree (a) of FIG. 2, the opening degree of the throttle valve 2 becomes the start target opening degree THM immediately after the first missing tooth is detected.

  After step S11, the ECU 9a stands by until the second missing tooth is detected by the crank angle sensor 25 (step S12). 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 S3, it is determined that the second missing tooth has been detected. When the ECU 9a determines that the second missing tooth has been detected, it determines the stroke of each cylinder (step S15). 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 S9 that the difference ΔT is equal to or greater than the reference pulse time interval T1, the ECU 9a stands by until the second missing tooth is detected by the crank angle sensor 25 (step S14). 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 S15). 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 S15 that the explosion is complete, the stroke of each cylinder is determined (step S16), and then the start target opening THM of the throttle valve 2 is set (step S17). A control signal indicating that the opening degree of the vehicle is set to the start target opening degree THM is output (step S18). Step S16 is the same process as step S13 described above, step S17 is the same process as step S10 described above, and step S18 is the same process as step S11 described above. That is, in the present embodiment, as shown by the throttle valve opening (b) in FIG. 2, when the difference ΔT is the reference pulse time interval T1 or more, the ECU 9a determines the throttle until one of the cylinders is completely detonated. It waits for the opening degree of the valve controller 9b to be 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 including the engine start control device 9 of the present embodiment as described above, the throttle valve is determined based on the maximum pulse time interval Tmax between the start of cranking and the simultaneous injection supplying fuel to the engine. Change the timing of setting 2 as the start target opening degree THM. The maximum pulse time interval Tmax changes due to the effects of compression loss and engine friction in the cylinders of the engine 20. Therefore, according to the engine control system 1 including the engine start control device 9 of the present embodiment, the timing at which the throttle valve 2 is made the target opening degree THM is adjusted in consideration of compression loss and engine friction in the cylinders of the engine 20. can do. Therefore, according to the engine control system 1 provided with the engine start control device 9 of the present embodiment, it is possible to start the engine 20 more reliably while enabling the engine rotational speed to be stabilized early.

  Further, in the engine control system 1 including the engine start control device 9 of the present embodiment, the throttle valve 2 is set to the target start opening degree THM based on the difference ΔT between the minimum pulse time interval Tmin and the maximum pulse time interval Tmax. Change the timing. In such a case, it is possible to adjust the timing at which the throttle valve 2 is set to the start target opening degree THM in consideration of a minute change of the minimum pulse time interval Tmin.

  Further, in the engine control system 1 including the engine start control device 9 of the present embodiment, as the maximum pulse time interval Tmax is larger (that is, as the difference ΔT is larger), the timing at which the throttle valve 2 is set as the start target opening THM is set. I'm late. The torque that needs to be generated by the cell motor 4 at the time of engine start decreases with the increase of the engine speed, and thus decreases with the passage of time. For this reason, as the maximum pulse time interval Tmax is larger (as the torque which can be generated by the cell motor 4 is smaller), the timing to set the throttle valve 2 to the start target opening THM is delayed, thereby more reliably preventing compression loss in the cylinder. can do.

  Further, in the engine control system 1 including the engine start control device 9 of the present embodiment, a masking period of a fixed period is provided from the start of cranking. For this reason, it is possible to obtain the maximum pulse time interval Tmax and the minimum pulse time interval Tmin while avoiding a period in which the influence of compression loss and the like immediately after the start of cranking is hard to understand. Therefore, it is possible to start the engine 20 more reliably.

  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, the configuration has been described in which the timing at which the throttle valve 2 is set to the start target opening THM is changed based on the difference ΔT between the minimum pulse time interval Tmin and the maximum pulse time interval Tmax. However, the present invention is not limited to this. For example, in the present invention, the timing of setting the throttle valve 2 to the target start opening degree THM may be changed based on the difference ΔT between the preset threshold value and the maximum pulse time interval Tmax. By adopting such a configuration, it is not necessary to obtain the minimum pulse time interval Tmin for the calculation of the difference ΔT, and the processing load on the ECU 9a can be reduced.

  Further, in the above embodiment, the configuration has been described in which the timing at which the throttle valve 2 is set to the start target opening degree THM is changed based on the difference ΔT between the minimum pulse time interval Tmin and the maximum pulse time interval Tmax. However, the present invention is not limited to this. For example, it is also possible to adopt a configuration in which the timing at which the throttle valve 2 is made the target opening degree THM is changed based on the ratio of the minimum pulse time interval Tmin and the maximum pulse time interval Tmax. It is also possible to adopt a configuration in which the timing of setting the throttle valve 2 to the target start opening degree THM is changed based on the ratio between the preset threshold value and the maximum pulse time interval Tmax.

  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 (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,
The timing at which the throttle valve is set to the start target opening degree is changed based on the maximum value of the pulse time interval of the crank angle sensor output signal from the start of cranking to the supply of fuel to the engine. Engine start control device.   The target value for starting the throttle valve is determined based on the difference or ratio between the minimum value of the pulse time interval of the crank angle sensor output signal input from the start of cranking to the supply of fuel to the engine and the maximum value. The engine start control device according to claim 1, wherein the timing of opening is changed.   The engine start control system according to claim 1, wherein the timing at which the throttle valve is set to the target opening degree is changed based on a difference or a ratio between a preset threshold value and the maximum value.   The engine start control device according to any one of claims 1 to 3, wherein the timing of setting the throttle valve to the start target opening is delayed as the maximum value is larger.   The engine start control device according to any one of claims 1 to 4, wherein a masking period of a fixed period is provided from the start of the cranking. 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,
The timing at which the throttle valve is set to the start target opening degree is changed based on the maximum value of the pulse time interval of the crank angle sensor output signal from the start of cranking to the supply of fuel to the engine. Engine start method.

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