JP2004245121A - Engine starter - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To enable speedy engine restart regardless of occurrence of abnormality such as belt breakage by speedily determining whether or not the start by a motor generator is allowed at engine restart of an idle stop vehicle or the like. <P>SOLUTION: When engine speed NE does not reach N1 after a lapse of time duration T1 from starting by the motor generator, the starting by a starter motor is performed. When the NE at Ti is N1 or more, the starting by the motor generator is continued, and, after that, when complete explosion does not occur in time duration T2, the starting by the starter motor is performed. <P>COPYRIGHT: (C)2004,JPO&NCIPI

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to an engine starter suitable for applications in which the engine is frequently stopped and started, such as a hybrid vehicle using both an engine and a motor.
[0002]
[Prior art]
2. Description of the Related Art As an engine starter applied to a conventional hybrid vehicle, there is an engine starter motor provided with a function of starting an engine in addition to a starter motor dedicated to starting. Generally, a motor generator larger than a starter motor is used for running or generating power of a vehicle. Therefore, when the engine is restarted from a temporarily stopped state during operation of the vehicle, the start is quickly completed by using a motor generator.
[0003]
[Patent Document 1] Japanese Patent Application Laid-Open No. 11-41707
[Problems to be solved by the invention]
In the motor-generator control at the time of starting, it is determined that the engine has completely exploded when the torque command value falls below a predetermined determination reference value. This is because the torque command value rises due to the power running of the motor generator, and then when the engine completely detonates and rotates on its own, the load on the motor generator decreases due to the generation of engine torque, and the torque command value falls accordingly.
[0005]
If the explosion is not completed even after a certain period of time has elapsed since the start cranking is started due to a failure of the motor generator or the rotation transmission system, the starter motor is started. At this time, since it takes a long time for the complete explosion determination by the motor generator, when a failure occurs, the restart is delayed, which is one factor that impairs the drivability of the hybrid vehicle.
[0006]
SUMMARY OF THE INVENTION It is an object of the present invention to provide an engine starting device capable of quickly starting an engine by a starter motor.
[0007]
Summary of the Invention
According to the present invention, a first motor and a second motor are provided for starting the engine. The driving state of each of the first motor and the second motor is controlled by the control device in the following manner in accordance with the rotation speed at the time of engine start detected by the rotation detection device.
(1) The start by the second motor is started when the engine speed when the first reference time has elapsed from the start of the engine start by the first motor is less than the first reference speed.
(2) When the engine speed at the time when the first reference time has elapsed is equal to or higher than the first reference speed, the engine start by the first motor is continued.
(3) If the engine does not completely explode during the continuation of the start by the first motor until the second reference time elapses, the start by the second motor is started.
[0008]
The first reference time and the first reference rotation speed in the control of the above (1) are a time and a rotation speed determined according to the engine as a measure of whether the engine can be started by starting (cranking) by the first motor. That is, if the engine speed does not reach the first reference speed before the first reference time elapses, it is determined that the complete explosion by the first motor is impossible, and the start by the second motor is started.
[0009]
When the engine speed is equal to or higher than the first reference speed and the combustion is not completed yet at the time when the first reference time has elapsed from the start of the start by the first motor, the start by the first motor is continued by the control of (2). . This is because if the rotation speed is equal to or higher than the first reference rotation speed, there is a high possibility that the first motor will completely start the combustion.
[0010]
Also, when the engine does not completely detonate during the continuation of the start by the first motor until the second reference time elapses, the control is switched to the start using the second motor by the control of (3).
[0011]
In the present invention, the first reference rotation speed and the first reference time, which are the references for determining whether or not the first motor can be started, are set, and the start by the first motor is continued or the start by the second motor is started. Is determined, it is possible to restart the engine in a minimum time regardless of the occurrence of an abnormality in the rotation transmission system of the first motor.
[0012]
BEST MODE FOR CARRYING OUT THE INVENTION
Hereinafter, an embodiment of the present invention will be described with reference to the drawings. This is an embodiment in which the present invention is applied to an engine of a so-called idle stop vehicle which automatically stops and restarts the engine at the time of a temporary stop / start at a traffic light or the like. FIG. 1 shows the engine system. In the figure, 1 is an engine body, 2 is a motor generator, 3 is a starter motor, and 4 is a controller.
[0013]
The motor generator 2 is connected to the engine 1 by a belt-pulley mechanism 5, and functions as a generator by driving the engine, and also functions as a starting motor that starts the engine 1 by a torque generated during power running control. Motor generator 2 exchanges power with first battery 7 as a high-voltage power supply via inverter 6. The starter motor 3 is used exclusively for starting the engine, and operates using a relatively low-voltage second battery 8 as a power supply. In relation to the present invention, the motor generator 2 corresponds to the first motor, and the starter motor 3 corresponds to the second motor.
[0014]
The controller 4 is composed of a microcomputer including a CPU and its peripheral devices. The controller 4 uses various signals representing the engine operating state to control the fuel injection amount of the engine 1, the ignition timing, the throttle opening, and the charge / discharge of the motor generator 2. This is a control device that comprehensively controls the engine 1 such as control and idle stop control according to the present invention. Reference numeral 9 denotes a battery controller, which monitors the voltage and current of the first battery 7 and supplies the state of charge (SOC) to the controller 4 for charge / discharge control.
[0015]
Regarding the idle stop control, the controller 4 sends to the controller 4 signals for determining the running state of the vehicle, such as a vehicle speed signal from a vehicle speed sensor 10, a brake operation signal from a brake sensor 11, an accelerator pedal operation amount signal from an accelerator sensor 12, and a water temperature. An engine cooling water temperature signal from the sensor 13 is input. Although various methods of idling stop control are known, in the above-described configuration, the engine is stopped when all of the conditions above the accelerator off, the vehicle speed is zero, the brake operation, and the water temperature reference value or more are satisfied, and the brake is released or the accelerator pedal is released from that state. The engine is restarted by depressing.
[0016]
FIG. 2 is a flowchart showing an outline of the idle stop control executed by the controller 4. This control is executed periodically, for example, every 10 ms. In the following description and the flowchart, reference symbol S represents a processing step. In this control, first, at S1, it is determined whether or not the engine is idling stop. If the engine is stopped, at S3, the condition detection based on the aforementioned sensor signal is performed in order to determine whether or not there is an idle stop release request. Next, in S3, it is determined whether or not the condition of the idle stop release request is satisfied. If the condition is satisfied, the start control for restart is performed in S5 (details will be described later with reference to FIGS. 3 and 4). Start). If the condition of the idle stop release request is not satisfied in S5, the process is terminated without doing anything.
[0017]
If it is determined in S1 that the engine is not idling stop, that is, it is determined that the engine is operating, the process proceeds to S2, and the set state of the engine stop prohibition flag is determined. This is because if the engine is stopped in a state where the belt pulley mechanism has an abnormality such as a broken belt, the engine may not be able to be started later. In this case, the subsequent processing is bypassed, and the engine is not stopped even if the engine stop request condition is satisfied in the future. When the engine stop prohibition flag is not set, the operation condition is detected from the sensor signal in order to determine the presence or absence of the idle stop request in S4, and it is determined whether or not the condition of the idle stop request is satisfied in S5. I do. When the condition of the idle stop request is satisfied, the idle stop process is performed in S8. When the condition is not satisfied, the current process is terminated without doing anything.
[0018]
FIG. 3 is a flowchart showing the details of the start control from the idle stop state in S5, and FIG. 5 is a timing chart relating to this control. Here, a timer used in the following processing will be described. In this control, T1 and T2 (however, T1 <T2) are applied as timer values indicating the elapsed time from the start of starting, and T3 is applied as a timer value for judging complete explosion. These are countdown timers. Since the processing cycle is 10 ms, each time the unit is reduced by one unit from the initial value, the countdown timer is decremented by 10 ms. The respective initial values are, for example, T1 = 50 (500 ms), T2 = 300 (3 sec), and T3 = 10 (100 ms), and these are initialized each time the engine is stopped due to idle stop.
[0019]
In FIG. 3, when the engine start is requested due to the satisfaction of the idle stop release condition (S3, S5 in FIG. 2), the engine start by the starter motor 3 (hereinafter referred to as "starter start") is not initially permitted. , S10 to S11, a powering command is output to the motor generator 2, and the motor generator 2 starts the engine start. The next step S13 is a process (hereinafter referred to as "belt determination") for determining the presence or absence of an abnormality such as a belt breakage or slippage in the belt pulley mechanism 5, the details of which are shown in FIG.
[0020]
In FIG. 4, first, at S30, it is determined whether or not T2 is an initial value (T2 = 300). If it is the initial value, the belt determination is permitted at S31, and a conditional branch at S32 is performed. The process proceeds to the belt determination process after S33.
[0021]
Since the belt determination permission state is maintained until the belt determination is completed in S38, the timer value T1 serving as a criterion for determining whether there is a belt abnormality is subtracted by the processing in S33 and thereafter until the end of the belt determination. Then, the process of determining whether or not T1 has become 0 in S34, that is, whether or not 500 ms have elapsed from the start of the start in this case, is repeated. The case where T1 = 0 in S34 is the case where the engine has not completely exploded by this time. This is the case where abnormality such as belt breakage or belt slippage is predicted, and the process proceeds to S35 and subsequent steps. . FIG. 5 shows a change in the engine speed when the belt is abnormal.
[0022]
When the engine speed NE is equal to or higher than the first reference speed N1 or when the voltage VB of the second battery 8 that is the power source of the starter motor 9 is lower than the reference voltage V1, the process proceeds to S38. Then, the belt determination is completed, T1 is initialized, and the flow returns to the flow of FIG. That is, when the engine speed is equal to or higher than the first reference speed or the voltage of the battery 8 is insufficient when T1 has elapsed, the engine start by the motor generator 2 is continued.
[0023]
However, when NE <N1 and VB ≧ V1, the engine stop prohibition flag is set in S37 and the start by the starter motor 3 is permitted. Then, the process returns to the flow of FIG. That is, when the engine speed is lower than the first reference speed and the battery voltage is sufficient at the time point of T1, the engine stop by the idle stop control is prohibited by the process of S2 in FIG. The operation is switched to the start of the engine by the starter motor 3.
[0024]
Returning to FIG. 3, following the belt determination in S13, it is determined in S25 whether or not a starter start permission condition is satisfied. As described with reference to FIG. 4, since starter start is not permitted until at least T1 has elapsed from the start of the start, the process proceeds to the next S14, and the timer value T2 is decremented by one unit. Next, through the processing of S15 to S18, a complete explosion determination is performed using the timer value T3. That is, if the state where the engine rotational speed NE is equal to or higher than the second reference rotational speed N2, which is a reference for complete explosion determination, is continued for the reference time T3 or more, T3 = 0, and the process proceeds to S19 and subsequent steps. The process proceeds to S20 and subsequent steps while maintaining the value. If the engine has completely started in T1 from the start of the start, the engine stop prohibition flag is reset in S19, the start request is canceled in S23, and the reinitialization processing of the timer and the like is performed in S24. In the re-initialization process in S24, the motor generator 2 and the starter motor 3 are turned off, and T2 and T3 are returned to the initial values.
[0025]
If the complete explosion has not been reached, it is first determined in S20 whether or not the second reference time T2 has elapsed. Initially, since T2 has not elapsed, the process bypasses S21 and thereafter, ends the current process, and returns to the beginning of the routine. At this point, the starter start is not permitted, so when returning to S10, the starting cranking by the motor generator 2 is continued by the processing up to S20 until the engine completely explodes or T2 elapses. If the explosion is completed by T2, the end processing after S19 is performed. If the explosion is not completed by T2, the process proceeds to S21. The process up to this point is a process that is performed when the process returns to S25 without setting the starter start permission state in the belt determination in FIG. 4 (FIG. 4), so that the process proceeds from the next condition determination in S21 to S22 and the starter start is permitted. After setting the state, reinitialization processing is performed in S24, and the routine returns to the beginning.
[0026]
In the next and subsequent processes, since the starter start permission state is determined in S10, the starter motor 3 is started in S12, and the engine start by the starter motor 3 is started. After the starter motor is started, the process is completed from S18 to S23 if the explosion is completed by the processing from S14 onward until T2 elapses. Proceeding from S21 to S23, the start is interrupted.
[0027]
In the belt determination process of S13 described above, when the engine speed NE has not reached the first reference speed N1 at the time when the first reference time has elapsed, and the battery voltage VB is equal to or higher than the reference voltage V1, That is, when a belt abnormality occurs, the process returns to S25 in FIG. 3 in a starter start permission state. In this case, after the reinitialization of S24 is directly executed by the determination in S25, the routine returns to the beginning. Also in this case, since the starter start permission state is determined in S10, the starter motor 3 is started in S12, and the engine start by the starter motor 3 is started.
[0028]
According to this control, it is determined whether or not the engine rotational speed has reached the cranking rotational speed N1 at which the engine can be started up until a certain time T1 elapses from the start of the start by the motor generator 2 to determine whether the belt has run out. When N1 is not reached due to an abnormality, the start is switched to the starter motor 3, so that even when an abnormality occurs, the engine can be started in a short time. If the engine speed at the time T1 has elapsed is equal to or higher than N1, the motor generator 2 continues to start as it is. Can be completed. Further, in this embodiment, the starter motor 3 is started only when the voltage of the battery 8 which is the power supply of the starter motor 3 is sufficient, so that the starter start-up speed and reliability can be further improved. .
[Brief description of the drawings]
FIG. 1 is a schematic configuration diagram of an embodiment of an engine to which the present invention is applied.
FIG. 2 is a first flowchart showing control operation contents according to the embodiment of the present invention.
FIG. 3 is a second flowchart showing control operation contents according to the embodiment of the present invention.
FIG. 4 is a third flowchart showing control operation contents according to the embodiment of the present invention.
FIG. 5 is a timing chart according to control of the embodiment of the present invention.
[Explanation of symbols]
1 engine body 2 motor generator (first motor)
3 Starter motor (second motor)
4 Controller (control device)
5 Belt Pulley Mechanism 6 Inverter 7 First Battery 8 Second Battery 9 Battery Controller 10 Vehicle Speed Sensor 11 Brake Sensor 12 Accelerator Sensor 13 Water Temperature Sensor

Claims (7)

First and second motors for starting the engine, respectively;
A control device for controlling each of the motors,
A rotation speed detection device that detects an engine rotation speed,
The control device,
When the engine rotation speed when the first reference time has elapsed from the start of the engine startup by the first motor is less than the first reference rotation speed, the start by the second motor is started, and the engine rotation when the first reference time has elapsed. When the number is equal to or higher than the first reference speed, the engine start by the first motor is continued,
An engine starting device, characterized in that the starting by the second motor is started when the engine does not completely detonate during the continuation of the starting by the first motor until the second reference time elapses. The engine starting device according to claim 1, wherein the control device stops the starting when the engine does not completely detonate after the start by the second motor. The control device determines that a complete explosion has occurred when the engine speed is equal to or higher than a second reference speed (where the second reference speed> the first reference speed) for a predetermined time, and ends the start. Alternatively, the engine starting device according to claim 2. The first motor is a motor generator having a function of generating power by driving the engine, the second motor is a starter motor mainly used for starting the engine, and the motor generator is operated by a high-voltage power supply storing the generated power. 2. The engine starting device according to claim 1, wherein the device is operated by a battery having a lower voltage than the high-voltage power supply. The control device starts the start by the second motor only when the voltage of the battery is equal to or higher than a reference voltage value when the engine speed after the first reference time has elapsed is lower than the first reference speed. The engine starting device according to claim 4, wherein The engine starting device according to claim 1, wherein the first motor and the engine are mutually transmitted by a belt-pulley mechanism. 2. The engine start according to claim 1, further comprising: a failure determination unit configured to determine that a failure has occurred when the engine speed when a first reference time has elapsed from the start of the engine start by the first motor is less than the first reference speed. 3. apparatus.

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