JP2018178901A - Start system control device of internal combustion engine - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a start system control device of an internal combustion engine, which can secure the start robustness of the internal combustion engine and the durability of a starter motor.SOLUTION: A control device is applied to a start system of an internal combustion engine, which has a starter motor, a battery, and an energization circuit leading from the battery to the starter motor. The energization circuit is configured to be switchable between a first path and a second path having a lower resistance than that of the first path. The control device starts the driving of the starter motor in a state of setting the energization circuit at the first path, further continues the driving of the starter motor in the state of setting the energization circuit at the first path in the case where the engine rotation speed is a predetermined rotation speed or more when the crank angle after the top dead center in a compression stroke of an initial explosion cylinder is a predetermined crank angle after first ignition timing of fuel in the initial explosion cylinder, and continues the driving of the starter motor while changing the energization circuit to the second path in the case where the engine rotation speed is lower than the predetermined rotation speed.SELECTED DRAWING: Figure 3

Description

  The present invention relates to a control device of a starting system of an internal combustion engine.

  In order to suppress a large current (hereinafter sometimes referred to as “inrush current”) flowing at the start of driving of the starter motor at the start of the internal combustion engine, there is also a case where it is referred to as inrush current suppression circuit (hereinafter “ICR”). It is known to provide).

  Patent Document 1 discloses, in a starting system of an internal combustion engine having an ICR, a technology for releasing the restriction of inrush current by the ICR after a predetermined time has elapsed from the start of driving of a starter motor.

JP, 2013-163980, A

  In the prior art, the restriction of the inrush current by the ICR is released at the timing at which the influence of the battery voltage drop due to the inrush current on the electric components of the vehicle is reduced. Then, when the restriction of the inrush current by the ICR is released, a relatively large current easily flows through the starter motor, and a torque for cranking the internal combustion engine generated by the starter motor (hereinafter referred to as "cranking torque" In some cases, it tends to increase. Here, in the situation where the engine rotational speed of the internal combustion engine rises relatively quickly, the start robustness of the internal combustion engine is easily ensured, and therefore, there is little need to increase the cranking torque.

  An object of the present invention is to provide a control device of a starting system of an internal combustion engine which can ensure the starting robustness of the internal combustion engine and the durability of the starter motor.

  In order to solve the above-mentioned problems, a control device of a starting system according to the present invention comprises a starter motor for generating a torque for cranking an internal combustion engine, a battery for supplying electric power to the starter motor, and the starter from the battery And an energizing circuit leading to a motor. The energizing circuit is configured to be able to switch between a first path and a second path having a smaller resistance than the first path, and the control device sets the energizing circuit to the first path. Driving of the starter motor at a start of the internal combustion engine, the crank angle after compression top dead center for the first firing cylinder is a predetermined crank angle after the first ignition timing of the fuel in the first firing cylinder And when the engine rotational speed of the internal combustion engine is equal to or higher than a predetermined rotational speed, the drive of the starter motor is continued with the energizing circuit set to the first path, and the engine rotation of the internal combustion engine If the speed is lower than the predetermined rotational speed, the energizing circuit is switched to the second path to continue driving the starter motor.

  According to the present invention, it is possible to provide a control device of a starting system of an internal combustion engine capable of securing the starting robustness of the internal combustion engine and the durability of the starter motor.

1 is a view showing a schematic configuration of an internal combustion engine according to an embodiment of the present invention. It is a figure showing a schematic structure of a starting system of an internal combustion engine concerning an embodiment of the present invention. It is a flowchart which shows the control flow performed in the control apparatus of the starting system of the internal combustion engine which concerns on 1st embodiment. FIG. 7 is a first time chart showing a temporal transition of a motor drive flag flagmt, a pinion push-out flag flagpg, a control state of an ICR, an ignition flag flagig, a second crank angle CA2, and an engine rotational speed NE in the first embodiment. FIG. 10 is a second time chart showing the time transition of the motor drive flag flagmt, the pinion push-out flag flagpg, the control state of the ICR, the ignition flag flagig, the second crank angle CA2, and the engine rotational speed NE in the first embodiment. It is a flowchart which shows the control flow performed in the control apparatus of the starting system of the internal combustion engine which concerns on 2nd embodiment.

  Hereinafter, with reference to the drawings, modes for carrying out the present invention will be exemplarily described in detail. However, the dimensions, materials, shapes, relative positions, etc. of components described in this embodiment are not intended to limit the scope of the present invention to them unless otherwise specified.

(First embodiment)
<Configuration of Internal Combustion Engine>
FIG. 1 is a view showing a schematic configuration of an internal combustion engine according to the present embodiment. An internal combustion engine 1 shown in FIG. 1 is a spark ignition type internal combustion engine (gasoline engine) provided with four cylinders 2. The internal combustion engine 1 is provided with a fuel injection valve 3 for directly injecting fuel into each cylinder 2 and an ignition plug 4 for igniting the air-fuel mixture.

  An intake passage 5 and an exhaust passage 6 are connected to the internal combustion engine 1. A throttle valve 51 is provided in the intake passage 5. The throttle valve 51 adjusts the intake air amount of the internal combustion engine 1 by changing the passage sectional area in the intake passage 5. In addition, the exhaust passage 6 is open to the atmosphere via a catalyst and a muffler (not shown).

  A crankshaft 7 is rotatably accommodated in a cylinder block of the internal combustion engine 1. The crankshaft 7 is connected to the flywheel 8. The flywheel 8 has a ring gear 81 at its outer periphery. The internal combustion engine 1 is cranked by the torque generated by the starter motor 11 in a state in which the pinion gear 12 of the starter 10 juxtaposed to the internal combustion engine 1 and the ring gear 81 are engaged with each other.

  Further, an electronic control unit (ECU) 20 is juxtaposed to the internal combustion engine 1. The ECU 20 is a unit that controls the operating state of the internal combustion engine 1 and the like. Various sensors such as a crank position sensor 9 are electrically connected to the ECU 20. The crank position sensor 9 is a sensor that outputs an electrical signal correlated with the rotational position of the engine output shaft (crankshaft 7) of the internal combustion engine 1. Then, the output signal of the sensor is input to the ECU 20. The ECU 20 derives the engine rotational speed of the internal combustion engine 1 based on the output signal of the crank position sensor 9.

Further, various devices such as the fuel injection valve 3, the spark plug 4, the starter 10, and the throttle valve 51 are electrically connected to the ECU 20. The ECU 20 controls these various devices. For example, when a start signal for the internal combustion engine 1 is input, the ECU 20 starts the internal combustion engine 1 by controlling these devices.

<Starting system of internal combustion engine>
FIG. 2 is a view showing a schematic configuration of a starting system of an internal combustion engine according to the present embodiment. The starting system shown in FIG. 2 has a starter 10, an ECU 20, and a battery 30. Here, when the starter motor 11 of the starter 10 and the battery 30 are connected by the energizing circuit 40, power is supplied from the battery 30 to the starter motor 11.

  The starter 10 is provided with an inrush current suppression circuit 13 (hereinafter sometimes referred to as “ICR 13”) in which a resistor 131 and a bypass relay 132 are connected in parallel. The bypass relay 132 has a contact 132A, and the opening and closing of the contact 132A is controlled by the ECU 20. Here, when the contact 132A is controlled to be open, the current from the battery 30 flows into the starter motor 11 through the resistor 131. On the other hand, when the contact 132A is controlled to be closed, the current from the battery 30 flows into the starter motor 11 via the bypass relay 132. That is, the energizing circuit 40 from the battery 30 to the starter motor 11 has a path through the resistor 131 (hereinafter may be referred to as "first path 40A") and a path through the bypass relay 132 (hereinafter, And may be referred to as "second path 40B".

  Here, since the resistor 131 functions as a resistance to the current flowing through the first path 40A having the resistor 131, the resistance of the first path 40A is larger than the resistance of the second path 40B having the bypass relay 132. Become. Then, when starting the driving of the starter motor 11, the ECU 20 controls the contact 132A to an open state. That is, the energizing circuit 40 is set to the first path 40A. Thereby, the large current (rush current) which flows at the time of the drive start of the starter motor 11 can be suppressed. The state in which the contact 132A is controlled to be in the open state, that is, the state in which the energizing circuit 40 is set to the first path 40A is hereinafter referred to as the "ICR-ON state". Further, a state in which the contact 132A is controlled to be closed, that is, a state in which the energizing circuit 40 is set to the second path 40B, is hereinafter referred to as "ICR-OFF state".

  The starter 10 also includes a coil relay 14 in the energizing circuit 40 between the ICR 13 and the starter motor 11. Then, when a start signal for the internal combustion engine 1 is input, the ECU 20 controls the contact 14A of the coil relay 14 in a closed state. Thus, the starter motor 11 is energized, whereby the driving of the starter motor 11 can be started. As described above, when starting the driving of the starter motor 11, the ECU 20 sets the energizing circuit 40 to the first path 40A. Further, the ECU 20 functions as the control device of the present invention by starting the driving of the starter motor 11 in a state where the energizing circuit 40 is set to the first path 40A.

<Start control of internal combustion engine>
Next, a control flow executed by the ECU 20, which is a control device for a starting system of an internal combustion engine according to the present invention, will be described based on FIG. FIG. 3 is a flowchart showing a control flow according to the present embodiment. In the present embodiment, when the start signal for the internal combustion engine 1 is input, the ECU 20 executes this flow.

  In this flow, first, in S101, the ICR-ON state is controlled. This suppresses the flow of a large current when the driving of the starter motor 11 is started in the process of S102 described later.

Next, in S102, driving of the starter motor 11 is started. The torque generated by the starter motor 11 is transmitted to the crankshaft 7 via the pinion gear 12 of the starter 10 and the ring gear 81 of the flywheel 8 connected to the crankshaft 7. 1 is cranked.

  Next, in S103, ignition is performed by the spark plug 4 in the first firing cylinder at the start of the internal combustion engine 1. In S103, ignition is performed at a predetermined timing after the first detonating cylinder first gets over the compression top dead center by the cranking of the internal combustion engine 1. Here, among the four cylinders 2 of the internal combustion engine 1, the first firing cylinder is defined as the cylinder 2 that first overcomes the compression top dead center after the start of cranking. In the first firing cylinder defined as described above, scavenging in the cylinder is performed in the process of stopping the internal combustion engine 1.

  Next, in S104, it is determined whether or not the crank angle after compression top dead center with respect to the first firing cylinder (hereinafter sometimes referred to as "first crank angle") CA1 has reached a predetermined crank angle CApr. . Here, the predetermined crank angle CApr is a predetermined crank angle after the first ignition timing of the first firing cylinder, and is stored in the ROM of the ECU 20. When the determination in step S104 is affirmative, the ECU 20 proceeds to the process of step S105. On the other hand, when a negative determination is made in S104, the ECU 20 repeats the process of S104.

  If an affirmative determination is made in S104, then it is determined in S105 whether the engine rotational speed NE at this time is equal to or higher than a predetermined rotational speed NEpr. Here, the predetermined rotational speed NEpr is a determination threshold value for determining whether or not starting of the internal combustion engine 1 can be completed relatively quickly in the ICR-ON state, and is stored in the ROM of the ECU 20 There is. If the determination in step S105 is affirmative, in this case, it is determined that the start of the internal combustion engine 1 can be completed relatively quickly in the ICR-ON state, and the ECU 20 proceeds to the process of step S106. On the other hand, if the determination in step S105 is negative, in this case, it is determined that the start of the internal combustion engine 1 can not be completed relatively quickly in the ICR-ON state, and the ECU 20 proceeds to the process of step S109.

  If an affirmative determination is made in S105, then it is determined in S106 whether or not a predetermined time has elapsed since the driving of the starter motor 11 was started in S102. Here, the predetermined time is a time which is determined in consideration of the startability of the internal combustion engine 1 and the durability of the starter motor 11, and is stored in the ROM of the ECU 20. At this time, control of the ICR-ON state is continued. When the determination in step S106 is affirmative, the ECU 20 proceeds to the process of step S107. On the other hand, when a negative determination is made in S106, the ECU 20 repeats the process of S106.

  When an affirmative determination is made in S106, next, in S107, the driving of the starter motor 11 is ended. As described above, the driving time of the starter motor 11 can be shortened by terminating the driving of the starter motor 11 after a predetermined time has elapsed after the driving of the starter motor 11 is started. In addition, since the control of the ICR-ON state is continued from the start of driving of the starter motor 11 in S102 to the end of driving of the starter motor 11 in S107, the motor is controlled while the starter motor 11 is being driven. The current flowing can be made relatively small. As a result of these, for example, the wear of the brush of the starter motor 11 can be suppressed, whereby the durability of the starter motor 11 can be secured. Next, in S108, the ICR-OFF state is controlled. And execution of this flow is ended after processing of S108.

In addition, when a negative determination is made in S105, next, in S109, the ICR-OFF state is controlled. As a result, the limitation of the inrush current by the ICR 13 is released, and a relatively large current flows through the starter motor 11. As a result, the cranking torque is increased. As described above, the start robustness of the internal combustion engine 1 is secured by controlling the ICR-OFF state and increasing the cranking torque.

  Next, at S110, it is judged if the engine rotation speed NE at this time is equal to or higher than the start determination rotation speed NEst. Here, the start determination rotational speed NEst is a determination threshold for determining whether or not the start of the internal combustion engine 1 can be completed even if the driving of the starter motor 11 is ended, and is stored in the ROM of the ECU 20 It is done. When the determination in S110 is affirmative, in this case, it is determined that the start of the internal combustion engine 1 can be completed even if the driving of the starter motor 11 is ended, and the ECU 20 proceeds to the process of S111. . On the other hand, if the determination in step S110 is negative, in this case, it is determined that the start of the internal combustion engine 1 can not be completed if the driving of the starter motor 11 is ended, and the ECU 20 performs the process of step S110. repeat.

  If a positive determination is made in S110, then the drive of the starter motor 11 is ended in S111. And execution of this flow is ended after processing of S111.

  By executing the above-described control flow, the ECU 20 can ensure start-up robustness of the internal combustion engine 1 and durability of the starter motor 11.

  In addition, the ECU 20 executes the process of S101 and S102 of the flow shown in FIG. 3 (the process of starting the driving of the starter motor 11 in the state where the energizing circuit 40 is set to the first path 40A). The process from S105 to S111 in the flow shown in (When the engine rotational speed NE is equal to or higher than the predetermined rotational speed NEpr, the drive of the starter motor 11 is continued with the energizing circuit 40 set to the first path 40A, and the engine rotational speed When NE is smaller than the predetermined rotation speed NEpr, the control device of the present invention is realized by executing the process of switching the energizing circuit 40 to the second path 40B and continuing the driving of the starter motor 11.

  Next, the control flow described above will be briefly described using a time chart. FIG. 4A shows a motor drive flag flagmt, which is a flag representing a drive state of the starter motor 11 and a push-out state of the pinion gear 12 of the starter 10, when the determination in step S105 shown in FIG. A flag representing a pinion pushout flag flagpg, a control state of the ICR 13 and an ignition flag flagig representing a timing of ignition by the spark plug 4 in the first firing cylinder of the four cylinders 2 of the internal combustion engine 1 Indicates the time transition of the crank angle after top dead center (hereinafter also referred to as "second crank angle") CA2 of the cylinder 2 in expansion stroke among the four cylinders 2 having the engine rotation speed NE It is a time chart.

  In the control shown in FIG. 4A, first, at time t1, a pinion pushout flag flagpg is set, and pushout control of the pinion gear 12 is executed. Then, at time t2, the motor drive flag flagmt is set, and the drive of the starter motor 11 is started. Thus, the starter 10 of the present embodiment is configured such that the pushing of the pinion gear 12 and the driving of the starter motor 11 are independently controlled. It is controlled to be in the ICR-ON state immediately before the start of driving of the starter motor 11.

Then, when driving of the starter motor 11 is started at time t2, the internal combustion engine 1 is cranked, and at time t3, the crank angle (second crank angle) CA2 after top dead center for the cylinder 2 in the expansion stroke is 180 deg. It becomes. That is, the cylinder 2 which is to be the expansion stroke next reaches the compression top dead center. Then, at a predetermined timing after the cylinder 2 first crosses over the compression top dead center, the ignition flag flagig is set and the first ignition is executed (in this way, the compression top dead center is first performed after the start of cranking) The cylinder 2 that overcomes is equivalent to the first firing cylinder.). Thereafter, at time t4 when the second crank angle CA2 becomes the predetermined crank angle CApr (that is, the first crank angle CA1 becomes the predetermined crank angle CApr) (in the control shown in FIG. 4A, the predetermined crank angle CApr is 90 deg. ), It is determined whether the engine rotational speed (NE1) at this time is equal to or higher than a predetermined rotational speed NEpr. In the control shown in FIG. 4A, since the engine rotational speed NE1 is equal to or higher than the predetermined rotational speed NEpr, the driving of the starter motor 11 is continued with the ICR-ON state. That is, driving of the starter motor 11 is continued in a state where the energizing circuit 40 is set to the first path 40A.

  Then, at time t5 when a predetermined time Δt has elapsed since the start of driving of the starter motor 11 (from time t2), the motor drive flag flagmt is lowered, and the driving of the starter motor 11 is ended. Further, the pinion pushing flag flagpg is lowered, and the pushing control of the pinion gear 12 is ended. Thereafter, at time t6, the ICR-OFF state is controlled. At the same time as the driving of the starter motor 11 is ended, the control may be controlled to the ICR-OFF state.

  Then, after time t6, the engine rotation speed NE relatively rapidly rises due to the combustion in the cylinder 2 of the internal combustion engine 1, and the start of the internal combustion engine 1 is completed relatively quickly. In such start control, the driving time of the starter motor 11 can be shortened. Further, the current flowing through the starter motor 11 can be made relatively small while the starter motor 11 is driven. As a result, for example, wear of the brush of the starter motor 11 can be suppressed, whereby the durability of the starter motor 11 can be secured.

  4B shows the motor drive flag flagmt, the pinion push-out flag flagpg, the control state of the ICR 13, the ignition flag flagig, the second crank angle CA2, and the negative judgment in the process of S105 shown in FIG. 5 is a time chart showing a time transition of an engine rotational speed NE.

  In the control shown in FIG. 4B, the same control as the control shown in FIG. 4A is executed until time t2. Then, when driving of the starter motor 11 is started at time t2, the internal combustion engine 1 is cranked, and at time t30, the crank angle (second crank angle) CA2 after top dead center for the cylinder 2 in the expansion stroke is 180 deg. It becomes. That is, the cylinder 2 which is to be the expansion stroke next reaches the compression top dead center. Then, at a predetermined timing after the cylinder 2 first passes over the compression top dead center, the ignition flag flagig is set and the first ignition is performed. Thereafter, at time t40 when the second crank angle CA2 becomes the predetermined crank angle CApr (that is, the first crank angle CA1 becomes the predetermined crank angle CApr) (in the control shown in FIG. 4B, the predetermined crank angle CApr is 90 deg. It is determined whether or not the engine rotational speed (NE2) at this time is equal to or higher than a predetermined rotational speed NEpr. Here, in the control shown in FIG. 4B, the engine rotational speed NE2 is smaller than the predetermined rotational speed NEpr. Therefore, at time t40, the ICR-OFF state is controlled. Then, the driving of the starter motor 11 is continued in the ICR-OFF state. That is, the drive circuit 40 is switched to the second path 40B, and the driving of the starter motor 11 is continued. As a result, the limitation of the inrush current by the ICR 13 is released, and a relatively large current flows through the starter motor 11.

  Then, at time t50 when the engine rotational speed NE becomes the start determination rotational speed NEst, the motor drive flag flagmt is lowered, and the drive of the starter motor 11 is ended. Further, the pinion pushing flag flagpg is lowered, and the pushing control of the pinion gear 12 is ended.

  Then, after time t50, the engine rotational speed NE is increased by the combustion in the cylinder 2 of the internal combustion engine 1, and the start of the internal combustion engine 1 is completed. In such start control, when the start of the internal combustion engine 1 can not be completed relatively quickly in the ICR-ON state, the internal combustion engine 1 is immediately controlled by the ICR-OFF state to increase the cranking torque. It is possible to ensure start-up robustness of the

Second Embodiment
Next, a second embodiment of the present invention will be described based on FIG. In the present embodiment, the detailed description of the configuration substantially the same as that of the first embodiment described above and the control processing that is substantially the same will be omitted.

  FIG. 5 is a flowchart showing a control flow according to the present embodiment. In the present embodiment, when the start signal for the internal combustion engine 1 is input, the ECU 20 executes this flow.

  In the flow shown in FIG. 5, first, at S201, fuel injection from the fuel injection valve 3 and ignition by the spark plug 4 are executed in the first explosion cylinder at the start of the internal combustion engine 1. In S201, fuel injection and ignition are performed in the first detonating cylinder in the expansion stroke, so that so-called ignition start is performed in which the start of the internal combustion engine 1 is started. Here, among the four cylinders 2 of the internal combustion engine 1, the first firing cylinder is defined as the cylinder 2 whose piston has stopped at the expansion stroke when the engine is stopped.

  Then, after the process of S201, in S101, the ICR-ON state is controlled. Then, in S102, driving of the starter motor 11 is started. As described above, in the start control according to the present embodiment, the ignition start is performed in S201, and the start assist by the starter motor 11 is performed in S102. Then, after the process of S102, in S104, it is determined whether or not the first crank angle CA1 has become the predetermined crank angle CApr. Here, the predetermined crank angle CApr is a predetermined crank angle after the timing at which the ignition start is performed in the first firing cylinder, and is stored in the ROM of the ECU 20.

  Also by executing the control flow described above by the ECU 20, the start robustness of the internal combustion engine 1 and the durability of the starter motor 11 can be ensured.

1 ··· Internal combustion engine 2 · · · Cylinder 3 · · · Fuel injection valve 4 · · · Ignition plug 7 · · · Crankshaft 8 · · · Flywheel 9 · · · Crank position sensor 10: Starter 11: Starter motor 12: Pinion gear 13: ICR
20 ・ ・ ・ ECU
30 ... battery 40 ... energizing circuit 40A ... first path 40B second path 81 ring gear 131 resistor 132 bypass relay 132A contact

Claims (1)

The invention is applied to a starting system of an internal combustion engine having a starter motor generating torque for cranking the internal combustion engine, a battery supplying power to the starter motor, and an energizing circuit from the battery to the starter motor A control device,
The energizing circuit is configured to be able to switch between a first path and a second path having a smaller resistance than the first path,
The controller is
Starting the driving of the starter motor with the energizing circuit set to the first path,
When the internal combustion engine is started, and the crank angle after compression top dead center with respect to the first explosion cylinder is a predetermined crank angle after the first ignition timing of the fuel in the first explosion cylinder, the engine of the internal combustion engine When the rotational speed is equal to or higher than the predetermined rotational speed, the drive of the starter motor is continued with the energizing circuit set to the first path, and the engine rotational speed of the internal combustion engine is smaller than the predetermined rotational speed. A control device of a starting system of an internal combustion engine, switching the energizing circuit to the second path and continuing the driving of the starter motor.

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