JP2010223007A - Automatic start-stop control device for internal combustion engine - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To improve the restartability of an internal combustion engine when a driver operates a clutch pedal in the direction for releasing the depression of the clutch pedal to request for restart during a fuel cutoff for idling stop control/fall of rotation of the internal combustion engine in a vehicle with a clutch on which an idling stop control system is mounted. <P>SOLUTION: When the driver operates the clutch pedal in the direction for releasing the depression of the clutch pedal during the fuel cutoff for idling stop control/fall of rotation of the engine, the automatic start/stop control device monitors the output of a clutch stroke sensor (depression amount of a clutch), and when the output of the clutch stroke sensor reaches a restart preparation determination value, predicts that a restart is requested soon, and switches the control amount (throttle opening) of the air system of the engine to a restart preparation control amount set between the control amount at that time and the control amount during the restart in preparation for the restart, and when the output of the clutch stroke sensor reaches the restart determination value and a request for restart occurs, restarts a fuel injection to restart the engine. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention provides a vehicle with a clutch (manual transmission vehicle) immediately when a restart request is generated while the rotational speed of the internal combustion engine (engine) is decreasing due to fuel injection stop by automatic stop control (idle stop control). The invention relates to an automatic stop / start control device for an internal combustion engine having a function of restarting the internal combustion engine.

  In recent years, vehicles equipped with an automatic engine stop / start control system (so-called idle stop control system) are increasing for the purpose of reducing fuel consumption and emission. In a conventional general idle stop control system, when the driver stops the vehicle, the fuel injection is stopped (fuel cut) to automatically stop the engine, and then the driver tries to start the vehicle. When an operation to perform (brake release operation, accelerator depression operation, etc.) is performed, the starter is automatically energized to crank the engine and restart it.

However, there is a limit to improving fuel efficiency by simply performing a fuel cut while the vehicle is stopped to stop the vehicle idle.
Therefore, recently, with the aim of further improving fuel efficiency, it is required to expand the fuel cut area of the idle stop control to the deceleration area at low speed that may cause the vehicle to stop while the vehicle is running. It has become to. Further, as described in Patent Document 1 (Japanese Patent Application Laid-Open No. 2008-267297), when a restart request is generated while the engine rotation speed is decreasing due to fuel cut for idle stop control, engine rotation is still performed. If the speed is in the rotational speed range where starterless start is possible (restartable only by fuel injection), the "starterless start" is performed in which the engine is restarted only by fuel injection without using a starter. is there.

  These idle stop control systems are often mounted on a vehicle with an automatic transmission, but are described in Patent Document 2 (Japanese Patent Laid-Open No. 2000-144718) and Patent Document 3 (Japanese Patent Laid-Open No. 11-257118). As shown, there are cases where a vehicle with a clutch (manual transmission vehicle) is also equipped with an idle stop control system.

JP 2008-267297 A JP 2000-144718 A JP-A-11-257118

  In a vehicle with a clutch (manual transmission vehicle) equipped with the idle stop control system, the vehicle stops when the driver depresses the brake pedal and depresses the clutch pedal to release the clutch while braking. It is judged that there is a possibility of a deceleration state, an automatic stop request (idle stop request) is generated and fuel injection is stopped, and in the process where the engine speed decreases due to this fuel injection stop (fuel cut), the driver When operating in the direction to release the pedal depression, it is considered that a restart request is generated to restart the fuel injection and restart the engine before the clutch is engaged. Yes.

  In this way, when a restart request is generated by the driver operating in a direction to release the depression of the clutch pedal during fuel cut / idle rotation of the idle stop control, the clutch is loosely connected after restart. However, when the driver suddenly releases the depression of the clutch pedal, the clutch is suddenly returned to the connected state immediately before or during the restart, and the engine and the vehicle drive system are directly connected. As a result, the engine load at the time of restarting suddenly increases and the restartability deteriorates. In the worst case, engine stall (engine stall) may occur.

  Therefore, the problem to be solved by the present invention is that in a vehicle with a clutch equipped with an idle stop control system, the driver releases the depression of the clutch pedal during idle stop control fuel cut / internal combustion engine rotation descent. An object of the present invention is to provide an automatic stop / start control device for an internal combustion engine that can improve restartability when a restart request is generated by operation.

  In order to solve the above-mentioned problems, the invention according to claim 1 detects a depression amount of a clutch that connects / disconnects a path for transmitting the power of the internal combustion engine to a drive system and a clutch pedal that switches connection / disconnection of the clutch. Clutch depressing amount detecting means for performing automatic stop control means for stopping fuel injection when an automatic stop request is generated during a period in which the driver depresses the clutch pedal and disengages the clutch during operation of the internal combustion engine And restarting by monitoring the presence or absence of a restart request based on the detection result of the clutch depression amount detection means while the rotational speed of the internal combustion engine is decreasing while the fuel injection is stopped by the automatic stop control means (during fuel cut) Automatic start control means for restarting fuel injection and restarting the internal combustion engine when a request occurs, and the automatic start control means comprises the clutch The amount of control of the internal combustion engine, the control amount at that time, the control amount at the time of restart, and the amount of control at the time of restart are prepared in preparation for restart when the occurrence of the restart request is predicted in advance based on the detection result of the switch depression amount detecting means. Is switched to the restart preparation control amount set during

  According to this configuration, when the occurrence of a restart request is predicted in advance based on the detection result of the clutch depression amount detecting means during fuel cut / internal combustion engine rotation descent in automatic stop control (idle stop control), restart is performed. In preparation for a restart, the control amount of the internal combustion engine can be switched to the restart preparation control amount so as to be close to the control amount at the time of restart. The change amount of the control amount when switching the control amount to the control amount at the time of restart can be reduced. As a result, it is possible to perform the restart by immediately changing to an operation state suitable for the restart while reducing the influence of the control system delay caused by the switching of the control amount when the restart request occurs. It is possible to increase the starting torque of the internal combustion engine, and even when the clutch is suddenly returned to the engaged state immediately before or during the restart, the internal combustion engine can be restarted with a larger starting torque than before. Thus, restartability can be improved and engine stall can be prevented. In addition, since the internal combustion engine can be restarted with a large starting torque, it is possible to shorten the time from when the restart request is generated until the restart is completed, and the clutch is suddenly returned to the engaged state immediately before or during the restart. The frequency (probability) can be reduced as compared with the prior art, and restartability can be improved from this aspect.

  In this case, the air system (for example, throttle opening, variable valve timing, variable valve lift, EGR valve, etc.) among the control amount of the internal combustion engine when the occurrence of the restart request is predicted in advance as in claim 2. The control amount of the airflow control valve, supercharger, variable intake device, etc.) may be switched to the restart preparation control amount. In the air system, the response delay from the change in the control amount to the change in the air condition in the cylinder is larger than that in the fuel system and the ignition system, so when the occurrence of a restart request is predicted in advance, If the control amount is switched to the control amount at the time of restart by switching the control amount to the restart preparation control amount, the response delay of the air system when the control amount of the air system is switched to the control amount at the time of restart is generated. It is possible to reduce the influence and immediately change the in-cylinder charged air amount or the like to a state suitable for restarting, and to effectively increase the starting torque of the internal combustion engine at the time of restarting. In addition, when the occurrence of the restart request is predicted in advance, the air system control amount is switched to the restart preparation control amount, so that the pumping loss can be reduced and the decrease in the internal combustion engine rotational speed can be moderated. Thus, the internal combustion engine rotational speed when the restart request is generated can be set to a higher rotational speed than before. For this reason, when the clutch is returned to the engaged state immediately before or during the restart, it is possible to restart and restart the fuel injection while rotationally driving the internal combustion engine using the deceleration energy of the vehicle. From this aspect, the startability can be improved.

  However, the present invention may switch the control amount of the fuel system and ignition system of the internal combustion engine to the restart preparation control amount when the occurrence of the restart request is predicted in advance. In the system, the control parameter that cannot ignore the influence of the response delay accompanying the switching of the control amount when the restart request is generated may be switched to the restart preparation control amount.

  The restart preparation control amount may be a constant value (fixed value) set in advance for the sake of simplification of the arithmetic processing. However, as described in claim 3, the clutch pedal control amount detected by the clutch depression amount detection means The restart preparation control amount may be set based on the change rate of the depression amount or information correlated therewith. In short, when releasing the depression of the clutch pedal, the faster the change rate of the depression amount of the clutch pedal, the shorter the time from when the restart request is predicted in advance until the actual restart request is generated Therefore, if the restart preparation control amount is set according to the changing speed of the depression amount of the clutch pedal, for example, as the changing speed of the depression amount of the clutch pedal becomes faster, Control that approaches the control amount is possible. Thereby, it is possible to appropriately set the restart preparation control amount according to the time from when the occurrence of the restart request is predicted in advance to when the restart request is actually generated.

  Further, the control amount at the time of restart may be set based on the detection result of the clutch depression amount detecting means. In this way, the amount of control at the time of restart can also be changed according to the detection result of the clutch depression amount detecting means. For example, the control at the time of restart becomes faster as the change rate of the amount of depression of the clutch pedal becomes faster. It is possible to control the amount to change in the direction of increasing torque, and even when the clutch is suddenly returned to the connected state immediately before or during the restart, the internal combustion engine can be restarted by increasing the starting torque. .

  The inventions according to claims 1 to 4 described above are applicable to any of an intake port injection type internal combustion engine, a cylinder injection type internal combustion engine, and a dual injection type internal combustion engine that uses both intake port injection and cylinder injection. Although it is possible, when applied to an intake port injection type internal combustion engine, as in claim 5, when the restart request is generated in a rotational speed region that can be restarted only by fuel injection, immediately at least the first By executing the fuel injection by “asynchronous injection” and then returning to “synchronous injection”, a starterless start in which the internal combustion engine is restarted only by fuel injection without using the starter may be performed.

  In this way, when a restart request is generated in a rotational speed range that can be restarted only by fuel injection, if at least the first fuel injection is immediately executed by “asynchronous injection”, the intake stroke is in effect when the restart request occurs. Asynchronous injection fuel is sucked into the cylinder and ignited in the vicinity of the next compression TDC to cause the first combustion (first explosion). This shortens the period from the restart request occurrence to the first explosion occurrence by one stroke (180 CA for a 4-cylinder engine and 120 CA for a 6-cylinder engine) compared to the conventional restart control using only synchronous injection. It is possible to generate an initial explosion at the same time, and accordingly, the frequency (probability) that the clutch is suddenly returned to the engaged state immediately before or during the restart can be reduced, thereby further improving the restartability. be able to.

However, according to the present invention, starterless start may be performed by restarting fuel injection only by synchronous injection from the beginning when a restart request is generated.
Further, the present invention is not limited to the configuration in which the starterless start is performed when the restart request is generated, and the internal combustion engine may be restarted using the starter when the restart request is generated.

FIG. 1 is a diagram showing a schematic configuration of a vehicle drive system in Embodiment 1 of the present invention. FIG. 2 is a schematic configuration diagram of the entire engine control system according to the first embodiment. FIG. 3 is a time chart for explaining an example of the restart control when the driver operates in the direction to release the depression of the clutch pedal during the fuel cut / engine rotation drop of the idle stop control of the first embodiment. FIG. 4 is a flowchart showing the flow of processing of the restart control program during idle stop according to the first embodiment. FIG. 5 is a time chart for explaining an example of restart control when the driver operates in a direction to release the depression of the clutch pedal during the fuel cut / engine rotation drop of the idle stop control according to the second embodiment.

  Hereinafter, two Examples 1 and 2 which embody the form for implementing this invention are demonstrated.

A first embodiment of the present invention will be described with reference to FIGS.
First, the configuration of the entire control system will be described with reference to FIG.
A clutch 13 that connects / disconnects the crankshaft of the engine 11 that is an internal combustion engine and the input shaft of the transmission 12 is provided, and the rotational force of the output shaft of the transmission 12 is propeller shaft 14 → differential gear. 15 → is transmitted to the drive wheel 17 through the path of the drive shaft 16. The transmission 12 is a manual transmission, and the driver performs a shift operation for switching the shift position of the shift lever 18 to switch the gear position of the transmission 12. The transmission 12 is provided with a shift switch 19 that detects the shift position of the shift lever 18.

  The vehicle is provided with a clutch pedal (not shown) for switching connection / disconnection of the clutch 13, the clutch 13 is disconnected by depressing the clutch pedal, and the clutch pedal is released by releasing the depressing operation of the clutch pedal. 13 is connected. The amount of depression of the clutch pedal is detected by a clutch stroke sensor 20 (clutch depression amount detection means). The engine 11 is provided with a starter 21 for rotationally driving (cranking) the crankshaft 37 at the start other than the starterless start.

  The starter 21 may use a starter that protrudes pin-on and meshes with the link gear on the engine 11 side only at the start other than the starterless start-up, or the pin-on is always meshed with the link gear and restarted. A constant mesh starter configured to crank the engine 11 at any time in response to a start request may be used. Alternatively, during engine operation, the pin-on is made to stand by with the link gear removed, and when a restart request is generated during the engine rotation drop period due to the automatic stop (idle stop) of the engine 11, the pin-on is rotated by the motor. The pinion rotation speed is synchronized with the rotation speed of the link gear, and when the difference between the two rotation speeds is reduced, the pinion is engaged with the link gear and cranking is started. good.

The engine 11 may be an injection type engine such as an intake port injection engine, an in-cylinder injection engine, or a dual injection engine that uses both intake port injection and in-cylinder injection.
In the first embodiment, a configuration example using the intake port injection engine 11 will be described with reference to FIG. An air cleaner 23 is provided at the most upstream portion of the intake pipe 22 of the engine 11, and an air flow meter 24 for detecting the intake air amount is provided downstream of the air cleaner 23. A throttle valve 26 whose opening is adjusted by a motor 25 and a throttle opening sensor 27 for detecting the opening (throttle opening) of the throttle valve 26 are provided on the downstream side of the air flow meter 24.

  Further, a surge tank 28 is provided on the downstream side of the throttle valve 26, and an intake pipe pressure sensor 29 for detecting the intake pipe pressure is provided in the surge tank 28. The surge tank 28 is provided with an intake manifold 30 that introduces air into each cylinder of the engine 11, and a fuel injection valve that injects fuel toward the intake port in the vicinity of the intake port of the intake manifold 30 of each cylinder. 31 is attached. In addition, a spark plug 32 is attached to the cylinder head of the engine 11 for each cylinder, and the air-fuel mixture in the cylinder is ignited by the spark discharge of each spark plug 32.

  On the other hand, the exhaust pipe 33 of the engine 11 is provided with an exhaust gas sensor 34 (air-fuel ratio sensor, oxygen sensor, etc.) for detecting the air-fuel ratio or rich / lean of the exhaust gas. A catalyst 35 such as a three-way catalyst for purifying gas is provided.

  A cooling water temperature sensor 36 for detecting the cooling water temperature is attached to the cylinder block of the engine 11. A crank angle sensor 38 that outputs a pulse signal every time the crankshaft 37 rotates by a predetermined crank angle is attached to the outer peripheral side of the crankshaft 37 of the engine 11, and an interval (cycle) of output pulses of the crank angle sensor 38 is set. Based on this, the engine rotation speed is detected, and the output pulse of the crank angle sensor 38 is counted based on the output signal of the cam angle sensor (not shown) or the missing tooth portion (reference crank angle) of the crank angle sensor 38. Thus, the detection of the crank angle and the cylinder discrimination [discrimination between the intake stroke cylinder (injection cylinder) and the compression stroke cylinder (ignition cylinder)] are performed.

  The control device 41 that controls the operating state of the engine 11 is configured by one or a plurality of ECUs (for example, an engine ECU and an idle stop ECU). The control device 41 includes various sensors for detecting an operation state, for example, the air flow meter 24, the throttle opening sensor 27, the intake pipe pressure sensor 29, the exhaust gas sensor 34, the cooling water temperature sensor 36, the shift switch 19, the clutch stroke. In addition to the signal from the sensor 20, the brake switch 42 for detecting the operation (ON) / non-operation (OFF) of the brake, the accelerator sensor 43 for detecting the accelerator opening (depressing amount of the accelerator pedal), the vehicle speed for detecting the vehicle speed A signal from the sensor 44 or the like is input.

  During engine operation, the control device 41 controls the fuel injection amount, injection timing, intake air amount (throttle opening), ignition timing, and the like of the engine 11 according to the operation state detected by the various sensors. Further, the control device 41 also functions as an automatic stop control means and an automatic start control means in the claims, and monitors whether or not an automatic stop request (idle stop request) is generated during engine operation. When an automatic stop request is generated, fuel injection is stopped (fuel cut), and combustion of the engine 11 is automatically stopped (idle stop).

  The automatic stop request may be generated after the vehicle is stopped (stopped). However, in the first embodiment, the vehicle can be stopped during traveling of the vehicle in order to expand the fuel cut region of the idle stop control. The automatic stop request is generated even in the deceleration area at a low speed. Specifically, it is determined whether or not a predetermined deceleration state that may cause the vehicle to stop while the vehicle is running (whether or not an automatic stop request is generated) is, for example, the following (1) to (4) Judgment is made based on whether all the conditions are satisfied.

(1) The clutch 13 is disengaged (the clutch pedal depression amount is greater than the disengagement judgment value)
(2) Brake is operating (Brake switch 42 is ON)
(3) Vehicle speed is below the specified vehicle speed
(4) Shift position is forward gear

  If all of these conditions (1) to (4) are satisfied, it is determined that the vehicle is in a predetermined deceleration state that may cause the vehicle to stop. Needless to say, the method for determining the predetermined deceleration state that may result in the vehicle stopping may be changed as appropriate.

  When it is determined that the vehicle is in a predetermined deceleration state that may cause the vehicle to stop during driving, it is determined that an automatic stop request (idle stop request) has occurred, fuel injection is stopped (fuel cut), The combustion of the engine 11 is automatically stopped (idle stop). Thereafter, when the driver operates in the direction of releasing the depression of the clutch pedal (in the direction of decreasing the depression amount) in the process of decreasing the engine speed due to the fuel cut, the output of the clutch stroke sensor 20 (the depression amount of the clutch 13). When a restart determination value set within the stroke range of the disengagement region of the clutch 13 is reached, a restart request is generated, fuel injection is restarted, and the engine 11 is restarted. Therefore, when the driver operates in a direction to release the depression of the clutch pedal, a restart request is generated and the engine 11 is restarted before the clutch 13 is engaged.

  In this way, when the driver operates in a direction to release the depression of the clutch pedal during fuel cut / idle rotation of the idle stop control and a restart request is generated, the clutch 13 is gently connected after the restart. Although it is desirable to return to the state, when the driver suddenly releases the depression of the clutch pedal, the clutch 13 is suddenly returned to the connected state immediately before or during the restart, and the engine 11 and the vehicle drive system are suddenly connected. As a result, the engine load suddenly increases and the restartability may deteriorate.

  As a countermeasure against this, in the first embodiment, as shown in FIG. 3, when the driver operates in a direction to release the depression of the clutch pedal during the fuel cut of the idle stop control / descent of the engine rotation, the clutch stroke sensor 20 Output (the amount of depression of the clutch 13) is monitored, and when the output of the clutch stroke sensor 20 reaches the restart preparation determination value, it is predicted that the restart request is near and the restart is performed at that time. In preparation for this, the control amount of the air system of the engine 11 (throttle opening in the first embodiment) is switched to the restart preparation control amount set between the control amount at that time and the control amount at the time of restart, and thereafter When the output of the clutch stroke sensor 20 reaches the restart determination value, a restart request is generated, fuel injection is restarted, and the engine 11 is restarted. As shown in FIG. 3, both the restart preparation determination value and the restart determination value are set within the stroke range of the disengagement region of the clutch 13, and the restart preparation determination value is greater than the restart determination value. It is set to a position where the amount of depression is large (a position where the amount of return from the maximum depression position is small).

  Next, an example of the idle stop control / restart control of the first embodiment will be described with reference to FIG. During engine operation, at the time t1 when the automatic stop request is generated, the fuel injection is stopped and the throttle opening is switched to the fully closed state. When the driver operates in a direction to release the depression of the clutch pedal during fuel cut / engine rotation drop of the idle stop control, a restart request is made at time t2 when the output of the clutch stroke sensor 20 reaches the restart preparation determination value. Therefore, the throttle opening, which is the air system, is switched from the fully closed position to the restart preparation opening (restart preparation control amount) in preparation for restart. The restart preparation opening is set between the immediately preceding throttle opening (fully closed) and the throttle opening at the time of restart.

  In the air system, the response delay from the change in the throttle opening to the change in the in-cylinder charged air amount is larger than that in the fuel system and the ignition system. If the throttle opening is close to the throttle opening at the time of restart and the throttle opening is changed to the throttle opening at the time of restart, Can be small. Thereby, it is possible to reduce the influence of the response delay of the air system and immediately change the in-cylinder charged air amount to an air amount suitable for restarting, and increase the starting torque of the engine 11 at the time of restarting. it can. Moreover, when the occurrence of a restart request is predicted in advance, the throttle opening is opened to the restart preparation opening, so that the pumping loss can be reduced and the decrease in engine speed can be moderated. The engine speed when the request is generated can be made higher than the conventional speed. For this reason, when the clutch 13 is returned to the engaged state immediately before or during the restart, it is possible to restart the fuel injection while restarting the engine 11 by using the deceleration energy of the vehicle. Thus, the startability can be improved.

  At time t3 when the output of the clutch stroke sensor 20 reaches the restart determination value, a restart request is generated, the throttle opening is opened from the restart preparation opening to the throttle opening at the restart, and ignition is performed. The fuel injection is restarted by advancing the timing and the engine 11 is restarted. As a result, it is possible to reduce the influence of the response delay of the air system accompanying the switching of the throttle opening when the restart request is generated, and to immediately perform the restart by changing the in-cylinder charged air amount suitable for the restart. The starting torque of the engine 11 at the time of restarting can be increased, and even when the clutch 13 is suddenly returned to the engaged state immediately before or during the restarting, the engine 11 is restarted with a starting torque larger than before. It becomes possible to make it. In addition, since the starting torque of the engine 11 at the time of restart can be increased, it is possible to shorten the time from when the restart request is generated to when the restart is completed, and the clutch 13 is suddenly connected immediately before or during the restart. The frequency (probability) to be returned to can be reduced as compared with the prior art, and restartability can be improved from this aspect.

The restart control during idle stop according to the first embodiment described above is executed by the control device 41 in the following manner according to the restart control program during idle stop of FIG.
The restart control program during idle stop in FIG. 4 is repeatedly executed at a predetermined period during the power-on period of the control device 41 (while the ignition switch is on), and serves as an automatic start control means in the claims. Fulfill. When this program is started, first, at step 101, it is determined whether or not the engine is idling stop (fuel cut). If it is not idling stop (fuel cut), idling stop (fuel cut is in progress). ) Wait until

  After that, when it is determined in step 101 that the engine is idling stop (fuel cut), the routine proceeds to step 102 where the output of the clutch stroke sensor 20 (the amount of depression of the clutch 13) is below the restart preparation determination value. Wait until

  Thereafter, when the output of the clutch stroke sensor 20 becomes equal to or less than the restart preparation determination value, it is predicted that the restart request is nearly generated, and the process proceeds to step 103, where the restart preparation opening (until the restart request is generated). Calculate the throttle opening during the period. The restart preparation opening degree may be a preset constant opening degree in order to simplify the arithmetic processing, for example, accelerator opening degree, engine rotation speed, cooling water temperature, intake pipe pressure, intake air amount, etc. The restart preparation opening degree may be calculated based on the engine operating state. Alternatively, first, the throttle opening at the time of restart is calculated based on the engine operating state such as the accelerator opening, the engine speed, the coolant temperature, the intake pipe pressure, the intake air amount, etc. A throttle opening corresponding to a predetermined ratio of the throttle opening may be set as the restart preparation opening. In short, the restart preparation opening may be a throttle opening located between the current throttle opening (fully closed) and the throttle opening at restart.

  Thereafter, the routine proceeds to step 104, the throttle opening is switched to the restart preparation opening in preparation for restart, and the routine proceeds to step 105, where it waits until the output of the clutch stroke sensor 20 becomes equal to or less than the restart determination value.

  Thereafter, when the output of the clutch stroke sensor 20 becomes equal to or less than the restart determination value, a restart request is generated, and the process proceeds to step 106 where the throttle opening at restart, the ignition timing at restart, the fuel at restart After calculating the injection amount, the routine proceeds to step 107, where restart control is executed, the throttle opening is opened to the throttle opening at restart, the ignition timing is advanced to the restart ignition timing, and fuel injection is resumed. Then, the engine 11 is restarted.

  At this time, if the engine speed at the time of the restart request is within a starterless start speed range (restartable only by fuel injection), the engine 11 is restarted only by fuel injection without using the starter 21. “Starterless start” may be performed. Further, when the engine 11 is an intake port injection engine, at the time when the restart request is generated, at least the first fuel injection is immediately executed by “asynchronous injection” and then returned to “synchronous injection”, whereby the starter 21 The starterless start may be performed in which the engine 11 is restarted only by fuel injection without using the engine. In this way, when a restart request is generated in a rotational speed range that can be restarted only by fuel injection, if at least the first fuel injection is immediately executed by “asynchronous injection”, the intake stroke is in effect when the restart request occurs. Asynchronous injection fuel is sucked into the cylinder and ignited in the vicinity of the next compression TDC to cause the first combustion (first explosion). This shortens the period from the restart request occurrence to the first explosion occurrence by one stroke (180 CA for a 4-cylinder engine and 120 CA for a 6-cylinder engine) compared to the conventional restart control using only synchronous injection. It is possible to generate the first explosion at the same time, and accordingly, the frequency (probability) that the clutch 13 is suddenly returned to the engaged state immediately before or during the restart can be reduced, thereby further improving the restartability. Can be made.

However, according to the present invention, starterless start may be performed by restarting fuel injection only by synchronous injection from the beginning when a restart request is generated.
Further, the present invention is not limited to a configuration in which a starterless start is performed when a restart request is generated. For example, in a vehicle equipped with a constant mesh starter, the engine is restarted during fuel cut / engine rotation descent for idle stop control. When a request occurs, the engine may be restarted by energizing a constant mesh starter. Or, while the engine is running, wait for the starter pin-on to be pulled out of the link gear, and when a restart request occurs during fuel cut / engine rotation drop of idle stop control, rotate the pin-on by the motor. When the rotational speed of the pinion is synchronized with the rotational speed of the link gear and the difference between the rotational speeds of the two becomes small, the pinion is meshed with the link gear to start cranking and restart the engine. .

  In the first embodiment described above, during the fuel cut / idle rotation of the idle stop control, the driver operates in a direction to release the depression of the clutch pedal, and the output of the clutch stroke sensor 20 indicates the restart preparation determination value. When it reaches the value, the occurrence of a restart request is predicted to be near, and in preparation for the restart, the throttle opening is set between the throttle opening at that time (fully closed) and the throttle opening at the time of restart. Therefore, the range of change in the throttle opening when the throttle opening is switched to the throttle opening at the time of restart when the restart request is generated can be reduced. As a result, the influence of the response delay of the air system accompanying the switching of the throttle opening at the time of restart can be reduced, and the cylinder charge air amount can be immediately changed to an air amount suitable for restart and restarted. Even if the starting torque of the engine 11 at the time of restarting can be increased and the clutch 13 is suddenly returned to the engaged state immediately before or during the restarting, the engine 11 can be restarted with a starting torque larger than the conventional one. This makes it possible to improve restartability and prevent engine stall. In addition, since the starting torque of the engine 11 at the time of restart can be increased, it is possible to shorten the time from when the restart request is generated to when the restart is completed, and the clutch 13 is suddenly connected immediately before or during the restart. The frequency (probability) to be returned to can be reduced as compared with the prior art, and restartability can be improved from this aspect.

  Furthermore, when the occurrence of a restart request is predicted in advance, the throttle opening is opened to the restart preparation opening, so that the pumping loss can be reduced and the decrease in engine speed can be moderated. The engine speed when the request is generated can be made higher than the conventional speed. For this reason, when the clutch 13 is returned to the engaged state immediately before or during the restart, it is possible to restart the fuel injection while restarting the engine 11 by using the deceleration energy of the vehicle. From this aspect, the startability can be improved.

Next, Embodiment 2 of the present invention will be described with reference to FIG. However, description of the same parts as those in the first embodiment will be omitted, and different parts will be described.
In the second embodiment, when the output of the clutch stroke sensor 20 (the amount of depression of the clutch 13) reaches the restart preparation determination value, the immediately preceding change speed of the output of the clutch stroke sensor 20 or information correlated therewith ( For example, the restart preparation opening degree is set based on the output change amount per predetermined time. In short, when releasing the depression of the clutch pedal, the faster the change rate of the clutch pedal depression amount, the shorter the time from when the restart request is predicted in advance until the actual restart request is generated. Therefore, if the restart preparation opening is set according to the change speed of the depression amount of the clutch pedal, for example, as the change speed of the depression amount of the clutch pedal becomes faster, the restart preparation opening degree Control to approach the throttle opening becomes possible. Thereby, the restart preparation opening degree can be appropriately set according to the time from when the occurrence of the restart request is predicted in advance to when the restart request is actually generated.

  In the second embodiment, the change rate of the output of the clutch stroke sensor 20 during the restart preparation period (t2 to t3) in which the throttle opening is switched to the restart preparation opening or information correlated therewith (for example, per predetermined time). The throttle opening and / or the ignition timing at the time of restart are set based on the output change amount). In this way, the amount of control at the time of restart can also be changed according to the change speed of the output of the clutch stroke sensor 20, so that, for example, as the output change speed of the clutch stroke sensor 20 becomes faster, It is possible to control the throttle opening to change in the throttle opening increasing direction, which is the torque increasing direction, or to change the ignition timing at the time of restarting to the advance direction, which is the torque increasing direction. Even when the clutch is suddenly returned to the engaged state during the restart, the engine 11 can be restarted by increasing the starting torque.

  It should be noted that the fuel injection amount at the time of restart, the fuel injection, based on the change speed of the output of the clutch stroke sensor 20 during the restart preparation period (t2 to t3) or information related thereto (for example, the output change amount per predetermined time). The timing, variable valve timing, etc. may be changed.

[Other Examples]
In the first and second embodiments, when the output of the clutch stroke sensor 20 reaches the restart preparation determination value during the fuel cut / engine rotation drop of the idle stop control, it is predicted that the restart request is nearly generated, In preparation for restart, the throttle opening, which is the control amount of the air system of the engine 11, is switched to the restart preparation opening (restart preparation control amount), but an air system other than the throttle, for example, variable valve timing, The control amount of the variable valve lift, EGR valve, airflow control valve, supercharger, variable intake device, etc. may be switched to the restart preparation control amount. In the air system, the response delay from the change in the control amount to the change in the air condition in the cylinder is larger than that in the fuel system and the ignition system, so when the occurrence of a restart request is predicted in advance, If the control amount is switched to the control amount at the time of restart by switching the control amount to the restart preparation control amount, the response delay of the air system when the control amount of the air system is switched to the control amount at the time of restart is generated. It is possible to reduce the influence and immediately change the in-cylinder charged air amount or the like to a state suitable for restarting, and to effectively increase the starting torque of the engine 11 at the time of restarting.

  However, the present invention is not limited to the configuration in which the control amount of the air system is switched to the restart preparation control amount at the time when the occurrence of the restart request is predicted to be near, for example, the occurrence of the restart request is predicted to be near At this point, the fuel system control amount (for example, fuel pressure) or the ignition system control amount may be switched to the restart preparation control amount. It is only necessary to switch the control parameter that cannot ignore the influence of the response delay accompanying the switching of the amount to the restart preparation control amount.

  Further, during engine operation, the starter 21 is pinned out from the link gear, and when it is predicted that a restart request is near, the pinon is rotated by the motor to reduce the rotation speed of the pinion. When the difference between the two rotational speeds becomes smaller in synchronization with the rotational speed, the pinion is engaged with the link gear. After that, when a restart request is generated, the starter 21 starts cranking and restarts the engine 11. You may make it start.

  DESCRIPTION OF SYMBOLS 11 ... Engine (internal combustion engine), 12 ... Transmission, 13 ... Clutch, 18 ... Shift lever, 19 ... Shift switch, 20 ... Clutch stroke sensor (clutch depression amount detecting means), 21 ... Starter, 22 ... Intake pipe, 26 DESCRIPTION OF SYMBOLS ... Throttle valve, 27 ... Throttle opening sensor, 29 ... Intake pipe pressure sensor, 31 ... Fuel injection valve, 32 ... Spark plug, 33 ... Exhaust pipe, 38 ... Crank angle sensor, 41 ... Control device (automatic stop control means, Automatic start control means), 42 ... brake switch, 43 ... accelerator sensor, 44 ... vehicle speed sensor

Claims (5)

A clutch for connecting / disconnecting a path for transmitting the power of the internal combustion engine to the drive system;
Clutch depression amount detecting means for detecting a depression amount of a clutch pedal for switching connection / disconnection of the clutch;
Automatic stop control means for stopping fuel injection when an automatic stop request is generated during a period in which the driver depresses the clutch pedal and disengages the clutch during operation of the internal combustion engine;
While the fuel injection is stopped by the automatic stop control means, the fuel is detected when the restart request is generated by monitoring the presence or absence of the restart request based on the detection result of the clutch depression amount detecting means while the internal combustion engine speed is decreasing. Automatic start control means for restarting the injection and restarting the internal combustion engine,
The automatic start control means sets the control amount of the internal combustion engine as the control amount at that time in preparation for restart when the occurrence of the restart request is predicted in advance based on the detection result of the clutch depression amount detection means. An automatic stop / start control apparatus for an internal combustion engine, wherein the control amount is switched to a restart preparation control amount set between a control amount and a restart control amount.   The automatic start control means switches an air system control amount to a restart preparation control amount among control amounts of the internal combustion engine when the occurrence of the restart request is predicted in advance. An automatic stop / start control device for an internal combustion engine as described.   The automatic start control means sets the restart preparation control amount based on a change speed of the depression amount of the clutch pedal detected by the clutch depression amount detection means or information correlated therewith. 3. An automatic stop / start control device for an internal combustion engine according to 1 or 2.   4. The automatic start control unit according to claim 1, wherein the automatic start control unit sets the control amount at the time of restart based on a detection result of the clutch depression amount detection unit. An automatic stop / start control device for an internal combustion engine as described. The internal combustion engine is an intake port injection type internal combustion engine,
When the restart request is generated in a rotational speed region that can be restarted only by fuel injection, the automatic start control means immediately executes at least the first fuel injection by asynchronous injection and then returns to synchronous injection. 5. An automatic stop / start control apparatus for an internal combustion engine according to claim 1, wherein starterless start is performed in which the internal combustion engine is restarted only by fuel injection without using a starter.

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