JP2018127995A - Electronic control device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an electronic control device capable of properly restarting an internal combustion engine after executing idle-stop control process for stopping an idle operation of the internal combustion engine when a vehicle provided with the internal combustion engine having a vaporizer is stopped and the like.SOLUTION: In an electronic device S, a control part 19 acquires a representative temperature of an internal combustion engine, calculates a restarting target step position of the internal combustion engine with the representation temperature reflected, stops an idling operation by an idle stop function, and then shifts the target step position of a stepping motor 26 from the target step position during an idle stop period to the restarting target step position.SELECTED DRAWING: Figure 1

Description

  The present invention relates to an electronic control device, and more particularly to an electronic control device that controls a carburetor provided in an internal combustion engine.

  Conventionally, a bleed valve that opens and closes an opening to a bleed air passage and adjusts a flow rate of air flowing into the bleed air passage (bleed air flow rate) in a carburetor provided in an internal combustion engine, and a bleed valve opening degree from a reference state. And a stepping motor that is controlled according to the number of steps, that is, the step position. In such a carburetor, in order to keep the air-fuel ratio of the air-fuel mixture supplied from the carburetor to the stoichiometric air-fuel ratio, it is necessary to control the bleed air flow rate according to the operating state of the internal combustion engine.

  Patent Document 1 relates to an air bleed control device for a carburetor, and by driving a stepping motor according to the operating state of the internal combustion engine, the opening degree of the valve body of the control valve device is set according to the operating state of the internal combustion engine. A configuration to control is disclosed.

JP-A 63-12870

  However, according to the study of the present inventor, the configuration of Patent Document 1 drives the stepping motor according to the operating state of the internal combustion engine, thereby opening the valve body of the control valve device according to the operating state of the internal combustion engine. Although it is intended to control the degree, idle stop control processing that stops the idle operation instead of maintaining the operation state of the internal combustion engine in the idle operation when the vehicle on which the internal combustion engine is mounted is stopped There is no disclosure or suggestion of a configuration for performing the above.

  In particular, according to the study of the present inventors, even in the case of a motorcycle such as a motorcycle equipped with an internal combustion engine provided with a carburetor in recent years, from the viewpoint of environmental performance and energy saving, when the vehicle is stopped, It is considered that there is a strong demand for appropriately executing the idle stop control process for stopping the idle operation of the internal combustion engine.

  Further, according to the study of the present inventor, when the idle stop control process is completed, the vehicle is in a state of starting, so it is necessary to appropriately restart the internal combustion engine and prepare for the starting of the vehicle. it is conceivable that.

  The present invention has been made after the above examination, and after the idle stop control process for stopping the idling operation of the internal combustion engine is executed, for example, when the vehicle equipped with the internal combustion engine provided with the carburetor is stopped. An object of the present invention is to provide an electronic control device capable of appropriately restarting an internal combustion engine.

  In order to achieve the above object, the present invention provides an electronic control device that performs an idle stop control process for stopping an idle operation of an internal combustion engine and has a control unit that controls a carburetor provided in the internal combustion engine. The carburetor includes a bleed valve that opens and closes an opening to a bleed air passage formed in the carburetor and can freely adjust a bleed air flow rate to the bleed air passage, and a stepping motor that drives the bleed valve. The control unit acquires a representative temperature of the internal combustion engine, calculates a restart target step position at the time of restart of the internal combustion engine by reflecting the representative temperature, and performs the idle operation by the idle stop function. After stopping, the target step position of the stepping motor is changed to the target step position in the idle stop period. It is transferred to the restart target step position from the first aspect of the.

  In the present invention, in addition to the first aspect, the control unit sets the reflected restart target step position to the representative temperature at the timing when the idle operation is stopped by the idle stop function and the elapsed time from the timing. The second aspect is to calculate according to the above.

  According to the electronic control device according to the first aspect of the present invention described above, the control unit acquires the representative temperature of the internal combustion engine, and reflects the representative temperature to restart target step position when the internal combustion engine is restarted. After the idle operation is stopped by the idle stop function, the target step position of the stepping motor is shifted from the target step position in the idle stop period to the restart target step position. The internal combustion engine can be restarted appropriately after the idle stop control process for stopping the idle operation of the internal combustion engine is executed, for example, when the vehicle equipped with the internal combustion engine is stopped. In particular, in such a configuration, in preparation for restart of the internal combustion engine, the bleed valve can be moved in advance to a restart target step position corresponding to the representative temperature of the internal combustion engine while the idling operation is stopped. Since the air-fuel ratio necessary for the initial explosion can be given in advance, the restartability of the internal combustion engine can be further improved as compared with the movement of the bleed valve during the restart of the internal combustion engine.

  Further, according to the electronic control device according to the second aspect of the present invention, the control unit corrects the restart target step position according to the elapsed time from the timing when the idle operation is stopped by the idle stop function. Therefore, it is possible to correct the restart target step position reflecting the representative temperature of the internal combustion engine at the timing of entering the idle operation stop state with the restart target step position reflecting the elapsed time of the idle operation stop state. Even when the idle operation is stopped for a relatively long time, a more appropriate restart target step position can be set, and the restartability of the internal combustion engine can be further improved. .

FIG. 1 is a block diagram showing a configuration of an electronic control device according to an embodiment of the present invention. FIG. 2 is a partial cross-sectional view showing a detailed configuration of the vaporizer (hereinafter referred to as a carburetor) shown in FIG. FIG. 3 is a timing chart as an example for explaining the flow of various processes including an initialization process, an open loop control process, a feedback control process, an idle stop control process, and the like executed by the electronic control unit according to the present embodiment. FIG. 4 is a flowchart showing the flow of the step position calculation process when the electronic control unit according to the present embodiment executes the idle stop control process.

  Hereinafter, an electronic control device according to an embodiment of the present invention will be described in detail with reference to the drawings as appropriate.

[Configuration of electronic control unit]
First, with reference to FIG. 1, the structure of the electronic control apparatus in this embodiment is demonstrated in detail.

  FIG. 1 is a block diagram illustrating a configuration of an electronic control device according to the present embodiment.

  As shown in FIG. 1, the electronic control unit S in this embodiment is an internal combustion engine (hereinafter referred to as an engine) such as a gasoline engine mounted on a mounting body typified by a vehicle such as a motorcycle not shown. ) And controls the air-fuel ratio of the air-fuel mixture supplied from the carburetor 2 to the engine in accordance with the operating state of the engine, and includes an electronic control unit (hereinafter referred to as ECU) 10. Yes.

  The ECU 10 includes an A / D (Analog-to-Digital) converter 11, a waveform shaping circuit 12, a drive circuit 13, an ignition circuit 14, a timer 15, a ROM (Read-Only Memory) 16, a RAM (Random Access Memory) 17, An EEPROM (Electrically Erasable Programmable Read-only Memory) 18 and a central processing unit (hereinafter referred to as a CPU) 19 are provided. The CPU 19 functions as a control unit in the ECU 10.

The A / D converter 11 is an electric signal indicating the throttle opening degree of the engine output from the throttle opening degree sensor 21 provided in the carburetor 1, and the temperature of the engine coolant and lubricating oil output from the temperature sensor 2. The electric signal used as the engine representative temperature (engine representative temperature) and the electric signal indicating the oxygen concentration (rich / lean) in the exhaust gas of the engine output from the oxygen concentration (O ₂ ) sensor 3 Convert the form from analog form to digital form. The A / D converter 11 outputs the electrical signals thus converted to digital form to the CPU 19.

  The waveform shaping circuit 12 shapes a crank pulse signal corresponding to the rotation angle of the crankshaft 5a of the engine output from the crank angle sensor 4 to generate a digital pulse signal. Here, the crank angle sensor 4 detects the rotation angle of the crankshaft 5a by detecting the tooth portion 5c formed on the outer peripheral surface of the reluctator 5b rotating with the rotation of the crankshaft 5a. The waveform shaping circuit 12 outputs the digital pulse signal thus generated to the CPU 19.

  The drive circuit 13 includes a switching element (not shown) that is on / off controlled in accordance with a control signal from the CPU 19, and drives the stepping motor 26 provided in the carburetor 1 by turning on / off the switching element. A pulse signal for driving is output. Thereby, the stepping motor 26 provided in the carburetor 1 takes a step position (step angle) according to the number of pulses of the input pulse signal, that is, according to the number of steps.

  The ignition circuit 14 includes a switching element that is on / off controlled in accordance with a control signal from the CPU 19 and is not shown. By activating the switching element, the air-fuel mixture in the engine is ignited via the ignition coil 6b. The operation of the spark plug 6a is controlled.

  The timer 15 performs a time measurement process in accordance with a control signal from the CPU 19, and measures the time during which the fluctuation width when the step position of the stepping motor 26 is moved to vibrate converges within a predetermined width range. An AJC step position stabilization timer 15a is included.

  The ROM 16 is configured by a nonvolatile storage device, and stores control programs for initialization processing, open loop control processing, feedback control processing, and idle stop control processing, which will be described later.

  The RAM 17 is configured by a volatile storage device and functions as a working area for the CPU 19.

  The EEPROM 18 is configured by a writable nonvolatile storage device, and stores control data, learning values, and the like for initialization processing, open loop control processing, feedback control processing, and idle stop control processing described later.

The CPU 19 controls the overall operation of the ECU 10. In this embodiment, by executing a control program stored in the ROM 16, an engine speed calculation unit 19a, an engine complete explosion determination unit 19b, an AJC (Air Jet Control) control unit 19c, an O ₂ sensor output determination unit It functions as 19d and the idle stop control part 19e.

  The engine speed calculation unit 19 a calculates the engine speed (engine speed) using the digital pulse signal output from the waveform shaping circuit 12.

  The engine complete explosion determination unit 19b determines whether or not the engine has been completely exploded based on the engine rotation number (including information related to the complete explosion of the engine) calculated by the engine rotation number calculation unit 19a.

The AJC control unit 19c is a control unit for driving the stepping motor 26 of the carburetor 1. The AJC control unit 19c mainly moves the bleed valve 25 (see FIG. 2) between the fully closed position and the fully opened position, thereby stepping motor 26. The target step position is set irrespective of the rich / lean signal from the O ₂ sensor 3 and the stepping motor 26 is driven to the set target step position. In response to the open loop control processing and the rich / lean signal output from the O ₂ sensor, the stepping motor 26 is driven so that the air-fuel mixture supplied from the carburetor 1 to the engine becomes the target air-fuel ratio, and the bleed air flow rate is reduced. execute each air-fuel ratio feedback control process for adjusting (O ₂ feedback control process) . As an execution condition of the O ₂ feedback control process, the O ₂ sensor 3 is activated, and the engine speed calculated by the engine speed calculation unit 19 a and the throttle opening obtained from the throttle opening sensor 21 are set. It is mentioned that the relationship is within a predetermined O ₂ feedback execution area.

Based on the voltage value of the electrical signal indicating the oxygen concentration (rich / lean) in the engine exhaust gas output from the O ₂ sensor 3 that has passed through the A / D converter 11, the O ₂ sensor output determination unit 19 d ₍₂₎ The presence / absence of activation of the sensor 3 and the density (rich / lean) of the oxygen concentration in the exhaust gas are determined. The O ₂ sensor output determination unit 19d determines whether the O ₂ sensor 3 is activated or not based on the output voltage from the temperature sensor 2 in addition to the voltage value of the output signal of the O ₂ sensor 3. May be based on the engine representative temperature (the voltage value of the output signal of the temperature sensor 2 that has passed through the A / D converter 11).

  The idle stop control unit 19e executes idle stop control for stopping the engine idle operation when a predetermined condition described later in detail is satisfied.

[Configuration of carburetor]
Next, the configuration of the carburetor 1 will be described in detail with reference to FIG.

  FIG. 2 is a partial sectional view showing a detailed configuration of the carburetor 1 shown in FIG. Note that the x-axis and z-axis in the figure form an orthogonal coordinate system.

  As shown in FIG. 2, the carburetor 1 is an electronic control type, and includes a bleed air passage 22, a first bleed air passage (slow passage) 23, a second bleed air passage (main passage) 24, a bleed valve 25, and a stepping motor. In addition to 26, all are provided with a main jet passage, a slow jet passage, a float chamber, etc., not shown.

  The bleed air passage 22 is an upstream side for supplying air (bleed air) sucked from an air cleaner (not shown) to the main jet passage and the slow jet passage via the first bleed air passage 23 and the second bleed air passage 24. It is a passage part.

  The first bleed air passage 23 is a flow passage that communicates with the bleed air passage 22 and then branches off at the opening 23b. The air that has been sucked into the bleed air passage 22 from the air cleaner through the communication passage 23a is a slow jet. It is a channel | path supplied to a channel | path. In the slow jet passage, the amount of fuel sucked up from the float chamber changes according to the flow rate of the bleed air flowing therethrough. That is, if the flow rate of the bleed air flowing in the slow jet passage is small, the amount of fuel sucked up from the float chamber is relative to the amount of intake air flowing in the intake passage 7 communicating between the air cleaner and the combustion chamber of the engine. On the contrary, if the flow rate of the bleed air is large, a large amount of air is supplied into the slow jet passage, so that the amount of fuel sucked up from the float chamber is relatively small with respect to the amount of intake air.

  The second bleed air passage 24 is a flow passage that communicates with the bleed air passage 22 and then diverges at the opening 24b. Air that has been sucked from the air cleaner and sucked into the bleed air passage 22 is communicated through the communication passage 24a. The passage is supplied to the main jet passage. In the main jet passage, the amount of fuel sucked up from the float chamber changes according to the flow rate of bleed air flowing therethrough. That is, if the flow rate of the bleed air flowing in the main jet passage is small, the amount of fuel sucked up from the float chamber is relative to the amount of intake air flowing in the intake passage 7 communicating between the air cleaner and the combustion chamber of the engine. Conversely, if the flow rate of the bleed air is large, a large amount of air is supplied into the main jet passage, so that the amount of fuel sucked up from the float chamber is relatively small with respect to the amount of intake air.

  The opening 24b in the main passage system including the second bleed air passage 24, the communication passage 24a and the opening 24b is more than the opening 23b in the slow passage system including the first bleed air passage 23, the communication passage 23a and the opening 23b. The z-axis is disposed on the negative direction side (the bleed valve 25 closing direction side). The air flow rate in the main passage system and the air flow rate in the slow passage system may be set to be different from each other.

  The bleed valve 25 is connected to the shaft 26a of the stepping motor 26, and the shaft 26a is moved in the z-axis direction by the operation of the stepping motor 26, whereby the first bleed air passage 23 is formed in the bleed air passage 22. A fully closed position that closes both the opening 23b of the first bleed air passage 24 and the opening 24b of the second bleed air passage 24, and a fully open position that opens both the opening 23b of the first bleed air passage 23 and the opening 24b of the second bleed air passage 24. Move between positions. When the position of the bleed valve 25 is at the fully closed position on the most negative side of the z-axis, the bleed valve 25 closes both the first bleed air passage 23 and the second bleed air passage 24. The bleed air is not supplied to the jet passage, and the air-fuel mixture supplied to the engine is in the richest state where the fuel ratio is the highest. On the other hand, when the position of the bleed valve 25 is in the fully open position on the most positive side of the z-axis, the bleed valve 25 opens both the first bleed air passage 23 and the second bleed air passage 24. In addition, the flow rate of the bleed air supplied to the slow jet passage becomes the largest, and the air-fuel mixture supplied to the engine becomes the leanest state where the ratio of the air is the highest. When the bleed valve 25 is located between the fully closed position and the fully open position, the bleed valve 25 opens the first bleed air passage 23 and the second bleed air passage 24 correspondingly. The air-fuel mixture supplied to the engine is in a state between the richest state and the leanest state. Thus, the bleed valve 25 opens and closes the opening 23 b of the first bleed air passage 23 and the opening 24 b of the second bleed air passage 24 and is supplied to the first bleed air passage 23 and the second bleed air passage 24. The air-fuel ratio of the engine mixture is adjusted by adjusting the air flow rate (bleed air flow rate).

  The stepping motor 26 drives the bleed valve 25 between the fully closed position and the fully open position by moving the shaft 26a connecting the bleed valve 25 in the z-axis direction according to the target step position.

The electronic control unit S having such a configuration obtains a reference step position of the stepping motor 26 that moves the bleed valve 25 by executing an initialization process, as shown below, and performs an open loop control process, O _2. Various processes such as a feedback control process and an idle stop control process are executed. Hereinafter, the operation of the electronic control device S when executing the initialization process, the open loop control process, the O ₂ feedback control process, and the idle stop control process will be described in detail with reference to FIG. Note that the initialization processing also shows post-initialization processing that is subsequently executed after completion of the original initialization processing for obtaining the reference step position of the stepping motor 26 by causing the bleed valve 25 to reach the fully open position. For convenience of explanation, this is also referred to as initialization processing.

[Various treatments]
FIG. 3 is a timing chart as an example for explaining the flow of various processes including an initialization process, an open loop control process, an O ₂ feedback control process, an idle stop control process, and the like executed by the electronic control unit S in the present embodiment. It is. Note that the amount of change in each step position in FIG. 3 is schematically shown.

First, when the ignition switch is turned on and the ECU 10 is activated in a period before time t = t0 shown in FIG. 3, the CPU 19 performs initialization processing, open loop control processing, O ₂ feedback control processing, and idle stop control. A program for executing the process is called from the ROM 16 to enter a standby state. These may be individual programs or integrated programs.

  Next, at time t = t0, the AJC control unit 19c starts initialization processing. At this time, when the engine complete explosion determination unit 19b determines that the engine has not been completely exploded based on the value of the complete explosion flag stored in the RAM 17, the AJC control unit 19c drives the stepping motor 26 to cause bleeding. The bleed valve 25 is moved from the fully closed position of the bleed valve 25 in the air passage 22 toward the fully open position, and an operation (AJC abutting operation) is started to drive the stepping motor 26 to abut against a stopper (not shown). To do. Such a stopper is fixed at a predetermined position in the carburetor 1 so that the bleed valve 25 does not move further in the opening direction beyond the fully opened position, and when the bleed valve 25 is abutted against the stopper, It will be in the fully open position. The initialization process is stopped by the AJC control unit 19c when the engine speed NE calculated by the engine speed calculation unit 19a becomes equal to or higher than a predetermined complete explosion speed during the execution of the process. .

  Next, in the period from time t = t0 to time t = t1, the engine speed NE has not exceeded the predetermined complete explosion speed in the initialization process, so the AJC control unit 19c starts at time t = t0. The AJC abutting operation is continued.

  Next, at time t = t1, in the initialization process, the bleed valve 25 is abutted against the stopper by the AJC abutting operation of the AJC control unit 19c, and is located at the fully open position. At this time, when the AJC control unit 19c determines that the AJC abutting operation is completed when the bleed valve 25 is abutted against the stopper and is located at the fully open position, the bleed valve 25 is abutted against the stopper. The step position of the stepping motor 26 when reaching the fully open position is acquired as the reference step position. Further, the value of the reference step position acquired by the AJC control unit 19c in this way is stored in the EEPROM 18, and the AJC control unit 19c sets the step position of the subsequent stepping motor 26 as the reference value (reference position). ). The limit step position in the figure is a limit step position on the opening direction side set in advance so that the bleed valve 25 does not hit the stopper during normal use. At time t = t1, the AJC control unit 19c performs stepping. An example in which the step position of the motor 26 is set by shifting to the limit step position is shown. Further, as the value of the limit step position, the value stored in advance in the EEPROM 18 is read and used.

  Next, in the period from time t = t1 to time t = t2, the initialization process causes the AJC control unit 19c to change the step position of the stepping motor 26 to the target step position (start target step position) at the start of the engine. Gradually decrease and migrate. Here, the position of the bleed valve 25 corresponding to the start target step position is such that the engine can be easily started and the engine speed NE can be made equal to or higher than a predetermined complete explosion speed (predetermined complete explosion NE). A bleed air flow rate for supplying an air-fuel mixture with a fuel ratio to the engine is realized. The engine speed NE used in the calculation process by the AJC control unit 19c is specifically the engine speed calculated by the engine speed calculation unit 19a using the digital pulse signal output from the waveform shaping circuit 12. The engine speed filtering value NEFLT smoothed by the filtering process. Further, the value of the start target step position is read out and used from the EEPROM 18 stored in advance.

  Next, at time t = t2, the step position of the stepping motor 26 reaches the start target step position, the AJC control unit 19c completes the initialization process, and sets the step position of the stepping motor 26 as the start target step position. Start open loop control processing.

  Next, in the period from time t = t2 to time t = t4, the AJC control unit 19c continues the open loop control process in which the step position of the stepping motor 26 started at time t = t2 is set as the start target step position. To do. Here, at time t = t3 between time t = t2 and time t = t4, the engine is started, and then the engine speed NE starts to increase.

  Next, at time t = t4, in the open loop control process in which the step position of the stepping motor 26 is set to the start target step position, the engine speed NE increases, and the AJC control unit 19c determines that the engine speed NE is It is determined that the predetermined complete explosion speed has been reached, and the step position of the stepping motor 26 is switched from the start target step position to the target step position during open loop control (open loop control target step position). Here, the position of the bleed valve 25 corresponding to the open loop control target step position is a position that realizes an appropriate air-fuel ratio based on the throttle opening TH, the engine speed, the engine representative temperature, the atmospheric pressure, etc., and is open. As the value of the loop control target step position, the value previously stored in the EEPROM 18 is read and used.

Next, in the period from time t = t4 to time t = t10, the AJC control unit 19c sets the step position of the stepping motor 26 started at time t = t4 as the open loop control target step position. Continue. At this time, the AJC control unit 19c gradually shifts the step position of the stepping motor 26 to the open loop control target step position over time. In this period, at time t = t5, the throttle opening TH starts to increase from the idle opening to the opening direction according to the opening operation of an accelerator operating member such as an accelerator grip (not shown) by the driver, At time t = t6, the engine speed NE exceeds the O ₂ feedback upper limit engine speed NE, and the voltage value of the output signal of the O ₂ sensor 3 that has passed through the A / D converter 11 has an amplitude of Coarse vibration with a long and long period has started. In the period from time t = t7 to time t = t8, the throttle opening TH becomes a constant opening larger than the idling opening in response to the opening of the accelerator operation member being maintained at a constant opening by the driver. In addition, the engine speed NE is maintained at a speed exceeding the O ₂ feedback upper limit engine speed NE. At time t = t9, the throttle opening TH reaches the idle opening in response to the closing operation of the accelerator operation member by the driver, and the engine speed NE decreases to about the O ₂ feedback upper limit engine speed NE. In response to determining that the vehicle is decelerating based on the throttle opening TH and the engine speed NE, the AJC control unit 19c sets the step position of the stepping motor 26 to the limit step position. When the bleed valve 25 is moved to the lean side in response to this, the voltage value of the output signal of the O ₂ sensor 3 that has passed through the A / D converter 11 sticks to the voltage value on the lean side. During the period from time t = t9 to time t = t10, the throttle opening TH is maintained at the idle opening according to the maintenance of the accelerator operating member to the closed position by the driver, and the engine speed NE is O _2. When the CPU 19 further decreases from the feedback upper limit engine speed NE, and the CPU 19 determines that the vehicle is not decelerating by the deceleration determination based on the throttle opening TH and the engine speed NE, the AJC control unit 19c The step position of the stepping motor 26 is shifted toward the open loop control target step position. During this period, the CPU 19 determines that the voltage value of the output signal of the O ₂ sensor 3 that has passed through the A / D converter 11 is within the range of the activation voltage width ΔV of the predetermined sensor, It is determined that the O ₂ sensor 3 is activated in response to the engine representative temperature calculated by the CPU 19 based on the output voltage being equal to or higher than a predetermined temperature, and the relationship between the engine speed NE and the throttle opening TH is The air-fuel ratio of the engine air-fuel mixture is theoretically determined according to the air-fuel ratio in the engine exhaust gas by determining that it is within a predetermined feedback execution region, that is, determining that the start condition of the O ₂ feedback control process is satisfied. O ₂ feedback control processing for feedback control to the air-fuel ratio is started. Since the step position at this time corresponds to the rich / lean oxygen concentration in the exhaust gas of the engine, as a result, the air-fuel ratio of the air-fuel mixture of the engine is included as one of the parameters. Step position for such O ₂ feedback control, after the start of the O ₂ feedback control process, takes a value that varies according to the control gain of the O ₂ feedback control process. Note that the value stored in the EEPROM 18 is read and used as the predetermined sensor activation voltage width ΔV. Also, O ₂ control gain of the feedback control process to prepare a large gain (first control gain) and less gain than this (second control gain), O ₂ at the time of entering the subsequent O ₂ feedback control process It is selectively used in the feedback control process (changed).

Next, at time t = t10, the AJC control unit 19c performs O ₂ feedback control processing with the first control gain. Here, since the output signal of the O ₂ sensor 3 shows a rich tendency at time t = t10, the step position is driven with the first control gain so that the position of the bleed valve 25 is shifted in the fully open direction. . As a result, since the air-fuel mixture becomes thin, the output signal of the O ₂ sensor 3 tends to be lean. Thus, when the output of the O ₂ sensor 3 tends to be lean, the step position is driven with the first control gain so that the position of the bleed valve 25 shifts in the fully closed direction. As a result, the output signal of the O ₂ sensor 3 shows a rich tendency. In this way, the AJC control unit 19c moves the step position to vibrate based on the rich / lean signal from the O ₂ sensor 3, and moves the bleed valve 25 along with this to adjust the amount of bleed air. Control is performed so that the air-fuel mixture becomes the stoichiometric air-fuel ratio. Here, since the first control gain takes a value larger than the second control gain described later, the step position moves greatly, and accordingly, the bleed valve position also moves largely. As a result, The amount of bleed air is also greatly changed. By setting the control gain to a large value in this way, when the engine state transitions from the transient state to the steady state, the mixing caused by the combustion reaction delay due to the transfer delay of the air-fuel mixture supplied from the carburetor 1 to the engine, etc. A so-called air-fuel ratio shift can be eliminated.

Next, in the period from time t = t10 to time t = t11, the AJC control unit 19c maintains the first control gain in the O ₂ feedback control process as it is, and the stepping motor 26 started at time t = t10. The drive control of the stepping motor 26 is continued so as to vibrate the step position relatively large. Here, the step position of the stepping motor 26 changes with a relatively large fluctuation width over a predetermined number of times (illustrated twice in the same shake direction in the drawing). The predetermined number of times can be set in accordance with engine characteristics and the like.

Next, at time t = t11, the AJC control unit 19c sets the step position of the stepping motor 26 to a second value smaller than the control gain in the O ₂ feedback control process in the period from time t = t10 to time t = t11. The O ₂ feedback control process is executed with the control gain, and the drive control for driving the stepping motor 26 is started. For this reason, the step position of the stepping motor 26 vibrates with a swing width smaller than the swing width in the period from time t = t10 to time t = t11.

Next, in the period from time t = t11 to time t = t12, the AJC control unit 19c continues the O ₂ feedback control process maintaining the second control gain, thereby starting the stepping started at time t = t11. The drive control of the stepping motor 26 that vibrates the step position of the motor 26 with a relatively small swing width is continued. Here, the step position of the stepping motor 26 oscillates with a relatively small fluctuation width, in other words, the air-fuel mixture matches the stoichiometric air-fuel ratio by moving back and forth finely from the step position that becomes the stoichiometric air-fuel ratio. Then, the O ₂ feedback control process is continued.

  Next, at time t = 12, the AJC control unit 19c determines that the peak in the vibration amplitude of the step position of the stepping motor 26 has converged within the range of the predetermined vibration width ΔW in the time-dependent change in the step position of the stepping motor 26. For example, when it is determined that the two consecutive peak amplitudes are within the range of the predetermined amplitude ΔW, the time counting operation of the AJC step position stabilization timer 15a is started. At this time, the throttle opening TH is continuously maintained at the idle opening according to the maintenance of the accelerator operation member to the closed position by the driver, and the engine speed NE is substantially equal to the idle target engine speed NETRG. It is stable at the idling engine speed that matches. Note that the value of the predetermined swing width ΔW is read out from the data stored in the EEPROM 18 in advance.

  Next, in the period from time t = 12 to time t = t13, the time counting operation of the AJC step position stabilization timer 15a is continued. Here, the step position of the stepping motor 26 continues to change so as to gradually decrease with time and exhibit a vibration with a smaller swing width. This means that the air-fuel mixture is maintained near the stoichiometric air-fuel ratio.

  Next, at time t = t13, the AJC control unit 19c determines that the throttle opening TH is at the idle opening, the engine representative temperature calculated by the CPU 19 is equal to or higher than a predetermined temperature, and the AJC step position stabilization timer 15a counts time. And when the idle stop control unit 19e determines that the engine speed NE is within a predetermined range between the idle lower limit engine speed NE and the idle upper limit engine speed NE. The idle stop control unit 19e starts the idle stop control process for stopping the engine, and the AJC control unit 19c starts the initialization process at the time of idle stop similarly to the initialization process started from time t = t0. At this time, the AJC control unit 19c calculates a step position (engine temperature reflection step position) STE reflecting the engine representative temperature when the engine enters the idle stop as soon as possible. Thus, the value of the engine temperature reflection step position STE acquired by the AJC control unit 19c is stored in the EEPROM 18. The engine representative temperature is typically the temperature of engine cooling water when the engine is water-cooled, and the temperature of engine lubricating oil when the engine is air-cooled, In either case, it is obtained using the electrical signal output from the temperature sensor 2. At this time, the AJC control unit 19c starts to calculate a step position (elapsed time reflecting step position) STI reflecting the elapsed time after entering the idle stop. Further, the value of the elapsed time reflecting step position STI acquired by the AJC control unit 19c in this way is stored in the RAM 17 for each control cycle during the period when the idle stop control process is being executed. Note that the initialization process at the time of idling stop is performed at another timing during the driving cycle even when the user starts the engine and stops during the initialization process starting from time t = t0. This makes it possible to perform initialization processing. Further, even when the initialization process started from time t = t0 is executed, the initialization process is executed for each idle stop, so that a more accurate reference step position can be acquired. Also, if the engine speed NE exceeds the predetermined complete explosion speed by detecting that the rider intends to start by opening the accelerator during the process and restarting the engine, the AJC The control unit 19c stops the initialization process at the time of idling stop. At this time, the step position of the stepping motor 26 is a restart target step position obtained by adding the engine temperature reflecting step position to the step position at the time of idling stop. Further, an elapsed time reflecting step position is added to the restart target step position according to the idle stop elapsed time. Further, when the reference step position is updated by the initialization process, the updated reference step position is used to correct the step position at the time of idling stop.

  Next, in a period from time t = t13 to time t = t16, the idle stop control unit 19e continues the idle stop control process started at time t = t13. Here, during the period from time t = t13 to time t = t14, the AJC control unit 19c drives the stepping motor 26 during the idling stop initialization process so that the bleed when the engine is stopped in the bleed air passage 22 is stopped. The bleed valve 25 is moved from the position of the valve 25 toward the fully open position, and the AJC abutting operation started at time t = t13 is continued. At time t = t14, the bleed valve 25 is abutted against the stopper by the AJC abutting operation of the AJC control unit 19c in the initialization process at the time of idling stop, and is located at the fully open position. At this time, when the AJC control unit 19c determines that the AJC abutting operation is completed when the bleed valve 25 is abutted against the stopper and is located at the fully open position, the bleed valve 25 is abutted against the stopper. The step position of the stepping motor 26 when reaching the fully open position is acquired as the reference step position. Further, the value of the reference step position acquired by the AJC control unit 19c in this way is stored in the EEPROM 18, and the AJC control unit 19c sets the step position of the subsequent stepping motor 26 as the reference value (reference position). ). Note that, at time t = t14, an example is shown in which the AJC control unit 19c sets the step position of the stepping motor 26 by shifting to the limit step position. In the period from time t = t14 to time t = t15, the AJC control unit 19c adds the step position of the stepping motor 26 to the step position at the time of idling stop by adding the engine temperature reflecting step position STE by the initialization process at idling stop. The restart target step position is gradually decreased with time and transferred. At time t = t15, the step position of the stepping motor 26 reaches the restart step position, and the AJC control unit 19c completes the initialization process at the time of idling stop and starts the open loop control process in preparation for the engine restart. Then, the step position of the stepping motor 26 is switched to a new restart target step position by adding the elapsed time reflecting step position STI to the restart target step position. In the period from time t = t15 to time t = t16, the AJC control unit 19c adds the elapsed time reflecting step position STI to the restart target step position obtained by adding the engine temperature reflecting step position STE of the stepping motor 26. Thus, the open loop control process started at time t = t15 for setting a new restart target step position is continued.

  Next, at time t16, the idle stop control unit 19e detects that the throttle opening TH is opened from the idle opening to the opening direction side by the operation of the accelerator operation member by the driver, and completes the idle stop control processing. And restart the engine. At this time, the AJC control unit 19c sets the step position of the stepping motor 26 from the restart target step position obtained by adding the engine temperature reflecting step position STE and the elapsed time reflecting step position STI to the step position at the time of idling stop. By switching to the new restart target step position updated by subtracting STI, the step position of the stepping motor 26 starts to move toward the restart target step position.

  Since the restart target step position described above is calculated based on the step position at the time of idling stop entry, the engine state at the time of restart is determined based on the step position at which the theoretical air-fuel ratio was obtained at the time of idling stop. It means that the step position is taken into account. By calculating the restart target step position in this way, it is possible to control the air-fuel mixture so as to realize an air-fuel mixture suitable at the time of restart, and the air-fuel mixture to quickly reach the stoichiometric air-fuel ratio after restart. Can be controlled.

Next, in a period after time t16, after the engine is restarted in a state where the throttle opening TH is continuously maintained at the idle opening in accordance with the maintenance of the accelerator operation member to the closed position by the driver, idle rotation is performed. Continuing, the step position of the stepping motor 26 reaches the start target step position and maintains the step position. Further, after the restart, the air-fuel ratio control is executed by open loop control for a predetermined time, and when a predetermined start condition is satisfied after the predetermined time has elapsed, the O ₂ feedback control process is started.

  Now, regarding the various processes executed by the electronic control unit S as described above, the operation of the electronic control unit S when executing the idle stop control process will be described in detail below with reference to FIG.

[Step position calculation process at idle stop]
FIG. 4 is a flowchart showing the flow of the step position calculation process when the electronic control unit S according to this embodiment executes the idle stop control process.

  As shown in FIG. 4, in the process of step S1, whether or not the value of the execution flag indicating whether or not the idle stop control unit 19e is executing the idle stop control process is 1 (already executed). By determining, it is determined whether or not the idle stop control process is being executed. Here, as the value of the execution flag, the value stored in the RAM 17 at the start of the idle stop control process is read and used. As a result of the determination, when the idle stop control process is being executed (the value of the idle stop control process execution flag is 1), the idle stop control unit 19e advances the step position calculation process at the time of idle stop to the process of step S2. On the other hand, when the idle stop control process is not being executed (the value of the idle stop control process execution flag is 0), the idle stop control unit 19e ends the step position calculation process during the current series of idle stops.

  In the process of step S2, the AJC control unit 19c determines whether or not the value of the execution flag indicating whether or not the initialization process at the time of idling stop is being executed is 1 (executed). It is determined whether or not the initialization process at the time of stop is being executed. Here, as the value of the execution flag, the value stored in the RAM 17 at the start of the initialization process at the time of idling stop is read and used. As a result of the determination, if the initialization process at the time of idling stop is being executed (the value of the initialization control process execution flag at the time of idling stop is 1), the AJC control unit 19c performs the step position calculation process at this series of idling stops. finish. On the other hand, when the initialization process at the time of idle stop is not being executed (the value of the initialization control process execution flag at the time of idle stop is 0), the AJC control unit 19c changes the step position calculation process at the time of idle stop to the process of step S3. Proceed.

  In the process of step S3, the AJC control unit 19c drives the stepping motor 26 to move the bleed valve 25 from the position of the bleed valve 25 when the engine is stopped in the bleed passage 22 toward the fully open position, An operation for driving the stepping motor 26 (AJC abutting operation) is executed to abut against the omitted stopper. Such a stopper is fixed at a predetermined position in the carburetor 2 so that the bleed valve 25 does not move further in the opening direction beyond the fully opened position, and when the bleed valve 25 is abutted against the stopper, It will be in the fully open position. Thereby, the process of step S3 is completed, and the step position calculation process at the time of idling stop proceeds to the process of step S4.

  Here, the timing at which the AJC control unit 19c starts moving the bleed valve 25 from the position of the bleed valve 25 to the fully open position when the engine is stopped is indicated by time t = t13 shown in FIG.

  In the process of step S4, the AJC control unit 19c calculates whether or not the target step position (engine temperature reflecting target step position) STE reflecting the engine representative temperature at the time of entering the idle stop control has been calculated. By determining whether or not the value of the flag is 1 (calculated), it is determined whether or not the engine temperature reflection target step position STE has been calculated. Here, as the value of the calculation flag, the value stored in the RAM 17 at the time of calculation of the engine temperature reflection target step position STE is read and used. As a result of the determination, when the engine temperature reflection target step position STE has been calculated (the value of the calculation flag is 1), the AJC control unit 19c advances the step position calculation process at the time of idling stop to the process of step S6. On the other hand, when the AJC abutting operation is not completed (the value of the calculation flag is 0), the AJC control unit 19c advances the step position calculation process at the time of idling stop to the process of step S5.

  In the process of step S5, the AJC control unit 19c acquires the value of the engine representative temperature detected by the temperature sensor 2 when the idle stop control is started. Thereby, the process of step S5 is completed, and the step position calculation process at the time of idling stop proceeds to the process of step S6.

  Here, the timing at which the AJC control unit 19c acquires the value of the engine representative temperature detected by the temperature sensor 2 when the idle stop control is started is indicated by time t = t13 shown in FIG.

  In the process of step S6, the AJC control unit 19c reads out table data indicating the relationship between the engine representative temperature and the engine temperature reflection target step position STE from the ROM 16, and corresponds to the value of the engine representative temperature acquired in the process of step S5. The engine temperature reflection target step position STE is calculated by searching the table data thus read for the value of the engine temperature reflection target step position STE. Thereby, the process of step S6 is completed, and the step position calculation process at the time of idling stop proceeds to the process of step S7.

  Here, the timing at which the AJC control unit 19c calculates the engine temperature reflection target step position STE is a time point at which it can be calculated as soon as possible after time t = t13 shown in FIG. In addition, the value of the engine temperature reflection target step position STE calculated by the AJC control unit 19c in this way is stored in the RAM 17.

  In the process of step S7, the AJC control unit 19c starts the time counting operation of the timer 15. Thereby, the process of step S7 is completed, and the step position calculation process at the time of idling stop proceeds to the process of step S8.

  Here, the timing at which the AJC control unit 19c starts the timing operation of the timer 15 is indicated by time t = t13 shown in FIG.

  In the process of step S8, the AJC control unit 19c reads out from the ROM 16 table data indicating the relationship between the elapsed time by the timer 15 and the elapsed time reflecting target step position STI, and the elapsed time acquired in the process of step S7. The elapsed time reflecting target step position STI is calculated by searching the table data read in this way for the value of the elapsed time reflecting target step position STI corresponding to. Thereby, the process of step S8 is completed, and the step position calculation process at the time of this series of idle stops ends.

  Here, the period during which the AJC control unit 19c calculates the elapsed time reflecting target step position STI is indicated by the period from time t = t13 to time t = t16 shown in FIG. Further, the value of the elapsed time reflecting target step position STI calculated by the AJC control unit 19 c in this way is stored in the RAM 17.

  As is apparent from the above description, in the electronic control unit S according to the present embodiment, the control unit 19 acquires the representative temperature of the internal combustion engine and reflects the representative temperature to restart the internal combustion engine when restarting. After calculating the step position and stopping the idle operation by the idle stop function, the target step position of the stepping motor 26 is shifted from the target step position in the idle stop period to the restart target step position. The internal combustion engine can be appropriately restarted after the idle stop control process for stopping the idle operation of the internal combustion engine is executed, for example, when the vehicle equipped with the internal combustion engine provided with is stopped. In particular, in such a configuration, in preparation for restart of the internal combustion engine, the bleed valve 25 can be moved in advance to a restart target step position corresponding to the representative temperature of the internal combustion engine while the idling operation is stopped. Since the air-fuel ratio necessary for the initial explosion of the engine can be given in advance, the restartability of the internal combustion engine can be further improved as compared with the movement of the bleed valve 25 during the restart of the internal combustion engine.

  Further, in the electronic control unit S according to the present embodiment, the control unit 19 corrects the restart target step position according to the elapsed time from the timing when the idle operation is stopped by the idle stop function. The restart target step position reflecting the representative temperature of the internal combustion engine at the timing of entering the stop state of the engine can be corrected with the restart target step position reflecting the elapsed time of the idle operation stop state. Even when the stop state is relatively long, a more appropriate restart target step position can be set, and the restartability of the internal combustion engine can be further improved.

  In the present invention, the type, shape, arrangement, number, and the like of the members are not limited to the above-described embodiment, and the gist of the invention is appropriately replaced such that the constituent elements are appropriately replaced with those having the same operational effects. Of course, it can be changed as appropriate without departing from the scope.

  As described above, the present invention appropriately executes the internal combustion engine after the idle stop control process for stopping the idle operation of the internal combustion engine is executed, for example, when the vehicle equipped with the internal combustion engine provided with the carburetor is stopped. An electronic control device that can be restarted can be provided, and is expected to be widely applicable to an internal combustion engine control device for a vehicle such as a motorcycle because of its universality.

S ... the electronic control unit 1 ... carburetor 2 ... Temperature sensor 3 ... oxygen concentration _{(O 2)} sensor 4 ... crank angle sensor 5a ... crankshaft 5b ... reluctor 5c ... teeth 6a ... spark plug 6b ... ignition coil 7 ... intake passage 10 ... ECU
DESCRIPTION OF SYMBOLS 11 ... A / D converter 12 ... Waveform shaping circuit 13 ... Drive circuit 14 ... Ignition circuit 15 ... Timer 15a ... AJC step position stabilization timer 16 ... ROM
17 ... RAM
18… EEPROM
19 ... CPU
19a ... engine speed calculating section 19b ... engine complete explosion determining unit 19c ... AJC controller 19d ... oxygen _{(O 2)} sensor output determining unit 21 ... Throttle opening sensor 22 ... bleed passage 23 ... first bleed air passage 23a ... Contact Passage 23b ... Opening 24 ... Second bleed air passage 24a ... Communication passage 24b ... Opening 25 ... Bleed valve 26 ... Stepping motor

Claims (2)

In an electronic control device that performs an idle stop control process for stopping an idle operation of the internal combustion engine and has a control unit that controls a carburetor provided in the internal combustion engine,
The vaporizer is
A bleed valve that opens and closes an opening to a bleed air passage formed in the carburetor and can adjust a bleed air flow rate to the bleed air passage;
A stepping motor for driving the bleed valve;
With
The controller is
After obtaining the representative temperature of the internal combustion engine, calculating the restart target step position at the time of restarting the internal combustion engine reflecting the representative temperature, and stopping the idle operation by the idle stop function, the stepping An electronic control device, wherein the target step position of the motor is shifted from the target step position in the idle stop period to the restart target step position. The controller is
The electronic control device according to claim 1, wherein the restart target step position is corrected according to an elapsed time from a timing at which the idle operation is stopped by the idle stop function.

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