JPH0925844A - Cranking start controller - Google Patents

Abstract

PROBLEM TO BE SOLVED: To suppress forward/afterward acceleration acting on a vehicle when cranking is started in a cranking start controller by which an internal combustion engine directly connected to the driving wheel of an automobile is started. SOLUTION: A subthrottle 38 is arranged in an intake manifold 28. An intake pressure sensor 36 is communicated with the intake manifold 28. In the case that starting is started while the driving wheel of a vehicle and an internal combustion engine 10 are directly connected to each other (clutch is connected), the subthrottle 38 is fully closed so as to reduce the volume of an intake pipe. At the point of time when intake pressure reaches a predetermined negative pressure, the subthrottle 38 is started to be opened as well as to start the execution of both fuel injection and fuel ignition.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a cranking start control device, and more particularly to a cranking start control device for starting an internal combustion engine that is directly connected to drive wheels of an automobile.

[0002]

2. Description of the Related Art Conventionally, as one of the methods for starting an automobile, a method for starting the vehicle by starting the internal combustion engine with the clutch engaged, that is, with the internal combustion engine and the driving wheels directly connected (hereinafter , Called cranking start) is known. The cranking start is used to restart the internal combustion engine, for example, when an engine stall occurs while traveling on a rugged road, a rocky road, etc. by a four-wheel drive vehicle. Since the drive wheels are directly connected to the internal combustion engine at the time of engine stall, the wheels are locked. On off-roads such as rubble roads and rocky roads, the vehicle often stops in an unstable state.Therefore, if the clutch is disengaged to restart the vehicle, the wheels may be unlocked and the vehicle may backtrack. . According to the cranking start mentioned above, even under such circumstances,
The vehicle can be restarted without backtracking.

When a cranking start is executed,
Immediately after starting cranking, the output torque of the starter motor or the like is transmitted to the drive wheels, and when the internal combustion engine is started thereafter, the output torque of the internal combustion engine is transmitted to the drive wheels. Therefore, the behavior of the vehicle at the time of executing the cranking start is greatly influenced by the behavior at the time of starting the internal combustion engine.

Techniques for controlling the behavior of an internal combustion engine at the time of starting are disclosed in, for example, Japanese Patent Laid-Open Nos. 63-11269, 61-66670, and 6-.
The technology disclosed in Japanese Patent Laid-Open No. 0-3451 or the like has been conventionally known. The above publication discloses a technique of stopping fuel injection at the start of cranking of an internal combustion engine and starting fuel injection when the intake pipe pressure drops to a predetermined negative pressure. At the start of cranking of the internal combustion engine, since the intake pipe is open to the atmospheric pressure, a relatively large amount of air is drawn into the combustion chamber even though the throttle valve is fully closed. On the other hand, the ignition characteristics during cranking are set so that good ignition characteristics can be obtained when the intake air amount is small. Therefore, in general, the internal combustion engine is in a state where it is difficult to obtain good ignition characteristics immediately after the start of cranking. On the other hand, according to the technique disclosed in the above publication, fuel is not injected until the intake pipe pressure reaches a predetermined negative pressure, so that it is possible to favorably start the internal combustion engine when fuel injection starts. .

The above publication discloses a technique in which ignition is performed by a spark plug in some cylinders when the diesel engine is started. A spark plug is essentially unnecessary for a diesel engine, which is a compression ignition type internal combustion engine. However, if a spark plug is used to positively ignite, even more excellent combustibility can be obtained. Therefore, as disclosed in the above publication, at the time of starting the diesel engine, if sparks are generated in some cylinders,
For example, it is possible to obtain excellent startability when cold.

The above publication discloses a technique for gradually reducing the fuel injection amount during cranking of the internal combustion engine to prevent an excessive supply of fuel when the start is delayed. The supplied fuel does not burn until the first explosion occurs in the internal combustion engine, so that the fuel is excessively supplied if the cranking period is prolonged. On the other hand, according to the device disclosed in the above publication, the fuel injection amount during cranking is gradually reduced so that the ideal state is maintained in order to obtain good startability. Therefore, according to such a device, good startability can always be obtained regardless of the length of the cranking period.

[0007]

However, the above conventional techniques are all techniques for obtaining good startability in an internal combustion engine. As described above, the behavior of the vehicle at the time of executing the cranking start is greatly affected by the startability of the internal combustion engine. However, if the internal combustion engine shows good startability at the start of cranking, that is, the internal combustion engine is in the stopped state. When a steady idling state is suddenly reached from the above, a large acceleration is generated in the vehicle in the process, which may give discomfort to the occupants of the vehicle.

On the other hand, the cranking start is a starting method which is usually executed after the warm-up of the internal combustion engine has already been completed. Therefore, when performing a cranking start,
This means that the internal combustion engine is in a state where it can be easily started. Therefore, in order to smoothly restart the vehicle by cranking start, priority is given to providing good startability, and the internal combustion engine is shifted from the stopped state to the steady idling state. It is desirable to add a property that enables smooth operation. In this respect, the above-mentioned various conventional techniques are not necessarily appropriate techniques for realizing a smooth cranking start.

The present invention has been made in view of the above-mentioned points, and controls an internal combustion engine that is directly connected to the drive wheels so that the internal combustion engine smoothly shifts from a stopped state to a steady idling state. It is an object to provide a cranking start control device.

[0010]

SUMMARY OF THE INVENTION The above object is to provide a cranking start control device for changing an internal combustion engine, which is directly connected to driving wheels of a vehicle, from a stopped state to a started state as described in claim 1 above. Intake pipe volume reducing means for reducing the volume of the intake pipe of the internal combustion engine at the start of cranking and permitting execution of both fuel injection and fuel ignition when the internal pressure of the intake pipe reaches a predetermined negative pressure This is achieved by a cranking start control device that includes an injection / ignition permitting means for performing the above-mentioned operation, and an intake pipe volume expanding means for expanding the volume of the intake pipe at a predetermined time after the start of cranking.

In the above invention, the intake pipe volume reducing means reduces the volume of the intake pipe at the start of cranking start. When the volume of the intake pipe is reduced, the amount of air to be discharged from the intake pipe in order to bring the internal pressure of the intake pipe to a predetermined negative pressure becomes small, and the intake pipe internal pressure becomes a predetermined negative pressure early after the start of cranking. Reach pressure.

When the internal pressure of the intake pipe reaches a predetermined negative pressure,
Both the fuel injection and the fuel ignition are permitted by the injection / ignition permitting means. An explosion occurs in the internal combustion engine when both fuel injection and fuel ignition are performed. At this time, since the intake pipe internal pressure has already reached a predetermined negative pressure and the intake air amount is small, the output torque of the internal combustion engine due to the explosion is suppressed to be small.

At a predetermined time after the start of cranking, the intake pipe volume expanding means expands the volume of the intake pipe.
When the volume of the intake pipe is increased, the amount of intake air to the internal combustion engine is also increased, and the output torque of the internal combustion engine is gradually increased.
Therefore, after a predetermined time, the internal combustion engine eventually reaches a steady idle state. At this time, the torque transmitted to the drive wheels directly connected to the internal combustion engine fluctuates smoothly in the process of the internal combustion engine shifting from the stopped state to the steady idle state.

Further, as described in claim 2, the above object is to provide a cranking start control device for changing the internal combustion engine directly connected to the drive wheels of the vehicle from the stopped state to the started state at predetermined timings. It is also achieved by a cranking start control device provided with an explosion stroke inhibiting means for inhibiting a part of the explosion stroke of the internal combustion engine to be executed during cranking.

In the above invention, the explosion stroke prohibiting means prohibits execution of part of the explosion stroke of the internal combustion engine when the cranking start is executed. When execution of a part of the explosion stroke is prohibited, the explosion stroke that should be executed at every predetermined timing is thinned out, and the unit time of the internal combustion engine is longer than that when all the explosion strokes are executed. The output energy per hit is reduced. In this case, it takes a relatively long period of time after the initial explosion of the internal combustion engine until the steady idle state is reached, and the change in torque transmitted to the drive wheels directly connected to the internal combustion engine is moderate. Becomes

Further, as described in claim 3, the above object is to provide a cranking start control device for changing the internal combustion engine directly connected to the drive wheels of the vehicle from a stopped state to a started state during a cranking period. Injected fuel integrating means for integrating the injected fuel, predetermined integrated amount detecting means for detecting that the integrated amount of injected fuel during the cranking period has reached a predetermined value, and integrated amount of injected fuel during the cranking period Is reached by the cranking start control device including fuel injection amount control means for controlling the fuel injection amount so that the amount of fuel adhering to the inner wall of the internal combustion engine becomes constant after reaching the predetermined value. It

In the above invention, the injected fuel integrating means integrates the total amount of fuel injected during the cranking period after the cranking start is started. The fuel injection amount control means controls the fuel injection amount so that the amount of fuel adhering to the inner wall of the internal combustion engine becomes constant after the accumulated amount of injected fuel during cranking reaches a predetermined value by the predetermined accumulated amount detecting means. To control. In this case, after the total amount of injected fuel reaches a predetermined value, the amount of fuel adhered to the inner wall of the internal combustion engine is maintained substantially constant, regardless of the length of the period until the initial explosion occurs in the internal combustion engine. Therefore, even when the cranking period is long, an unduly large output torque is not generated when the initial explosion occurs, that is, a large torque fluctuation is not transmitted to the drive wheels.

[0018]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS FIG. 1 shows an overall configuration diagram of an internal combustion engine 10 which is an embodiment of the present invention. The internal combustion engine 10 has a two-wheel drive (2WD) and four-wheel drive (4DW) drive system.
Is an internal combustion engine installed in a vehicle (part-time type 4WD) in which and can be selected.

In FIG. 1, the cylinder block 12 constitutes the main body of the internal combustion engine 10. A water jacket 14 through which cooling water circulates is provided in the wall of the cylinder block 12. The cylinder block 12 is provided with a water temperature sensor 16 for detecting the temperature of the cooling water flowing through the water jacket 14.

A piston 18 is housed in the cylinder block 12 so as to be liquid-tight and slidable. The internal combustion engine 10 of the present embodiment is a multi-cylinder internal combustion engine, and in the cylinder block 12, a plurality of pistons (not shown) are housed in addition to the piston 18. Further, inside the cylinder block 12, above the piston 18, the combustion chamber 20
Are formed. An ignition plug 22 is arranged in the combustion chamber 20, and an intake manifold 28 and an exhaust manifold 30 communicate with each other via an intake valve 24 or an exhaust valve 26, respectively.

The intake manifold 28 is provided with a plurality of branch pipes that connect each cylinder of the internal combustion engine 10 and the surge tank 32. Each branch pipe is provided with a solenoid valve type injector 34. In the internal combustion engine 10, the fuel injection amount can be changed by changing the time length of the drive signal supplied to the injector 34.

An intake pressure sensor 36 for detecting the internal pressure of the intake manifold 28 is connected to the intake manifold 28. Further, on the upstream side of the intake pressure sensor 36,
A sub-throttle valve 38 for controlling the communication state between each branch pipe of the intake manifold 28 and the surge tank 32 is provided. The sub throttle 38 is a step motor 40.
Is provided as a drive mechanism, and the opening can be arbitrarily adjusted by applying a control signal from the outside.

An intake pipe 40 is provided upstream of the surge tank 32.
Is communicated. Inside the intake pipe 40, a main throttle valve (hereinafter simply referred to as a throttle valve) 4
2 are provided. The throttle valve 42 is a valve that operates in conjunction with an accelerator pedal (not shown),
It is configured so that the opening degree is generated according to the depression amount of the accelerator pedal. In the vicinity of the throttle valve 42,
A throttle sensor 44 for detecting the opening is provided.

The intake pipe 40 and the surge tank 32 are connected by a bypass passage 46 that bypasses the throttle valve 42. Therefore, the throttle valve 42
Even if is fully closed, the internal combustion engine 10 is supplied with air if the bypass passage 46 is in the conductive state. An idle speed control valve (ISCV) 48 is provided in the bypass passage 46. The ISCV 48 is a valve mechanism including a step motor as a drive mechanism, and its opening can be arbitrarily changed according to a drive signal supplied from the outside.

An air flow meter 50 is connected to the intake pipe 40 upstream of the throttle valve 42. The air flow meter 50 generates an output signal according to the amount of air flowing inside. An intake air temperature sensor 52 is incorporated in the air flow meter 50. Intake air temperature sensor 52
Generates an output signal according to the temperature of the air flowing inside the air flow meter 50, that is, inside the intake pipe 40.
An air filter 54 is connected to the upstream side of the air flow meter 50. Therefore, the clean air that has been filtered by the air filter 54 flows into the intake pipe 40.

The water temperature sensor 16 and the spark plug 2 described above
2, the injector 34, the intake pressure sensor 38, the step motor 40, the throttle sensor 44, the ISCV 48, the air flow meter 50, and the intake air temperature sensor 54 are connected to an electronic control unit (ECU) 56. The ECU 56 is a main part of this embodiment, and controls the various actuators described above based on the output signals of the various sensors described above.

As shown in FIG. 1, in addition to the various sensors and actuators described above, the ECU 56 includes a cranking start button 58, a 4WD / 2WD selector switch 6
0, Hi / Lo switch 62, starter switch 64, and NE sensor 66 are connected.

When a 4WD vehicle running on a rugged road, a rocky road or the like has an engine stall, if the cranking of the internal combustion engine is restarted with the clutch engaged, the vehicle will be restarted without being returned. be able to. Such a restart method is called a cranking start, and is used as a method for restarting a vehicle off-road.

By the way, the cranking start is required when it is not desired to retreat the vehicle when restarting the internal combustion engine. For example, when the vehicle is running on level ground, the cranking start is performed. do not have to. Therefore, it is sufficient to carry out the cranking start only when the driver clearly indicates the intention.

Therefore, in the internal combustion engine 10, execution of cranking start is allowed only when the driver clearly indicates the intention, that is, rotation of the starter motor with the clutch still connected is allowed. Then
If the intention is not displayed, the rotation of the starter motor with the clutch still connected is prohibited.

The cranking start button 58 described above
Is a button provided as an input device for the driver to make such an intention display, and is provided on the left hand side of the driver in this embodiment. In addition, the starter switch 6 described above
Reference numeral 4 denotes a switch for operating the starter motor, which is arranged on the right hand side of the driver in this embodiment. E
The CU 56 permits execution of the cranking start only when the cranking start button 58 and the starter switch 64 are simultaneously operated by both hands.

The 4WD / 2WD switch 60 is
Drive systems for vehicles equipped with the internal combustion engine 10 from 4WD to 2
It is a switch used when switching from WD or from 2WD to 4WD. The Hi / Lo switch 62 is a switch used when switching the transmission gear ratio from the Hi mode to the Lo mode or from the Lo mode to the Hi mode. The Hi mode is used during normal traveling, and the Lo mode is used under conditions where the vehicle speed is low and large torque is required, such as during off-road traveling. Further, the NE sensor 66 is a sensor that detects the rotation speed of the internal combustion engine 56.

FIG. 2 shows a time chart for explaining the operation of the internal combustion engine 10 at the time of executing the cranking start. FIG. 2A shows a change state of the rotational speed NE of the internal combustion engine 10. The solid line in the figure shows the NE change situation when cranking is started by the method peculiar to this embodiment, and the broken line in the figure shows the cranking by the conventional method. The change situation of NE at the time of starting is shown respectively. The change shown in FIG.
_This is a change that occurs when the cranking start is started at time t ₁ after the internal combustion engine 10 has stopped due to engine stall at ₀ .

FIG. 2B shows the state of the starter switch 64 operated by the driver in executing the cranking start. The cranking of the internal combustion engine 10 is
As shown in the figure, it is started by turning on the starter switch 64 at time t ₁ . The starter switch 64 is turned off at an appropriate time t ₃ after the initial explosion occurs in the internal combustion engine 10.

FIG. 2C shows the pressure (hereinafter referred to as intake negative pressure) PM in the intake manifold 28 detected by the intake pressure sensor 36. In the figure, the vertical axis represents the magnitude of negative pressure, and "0" represents atmospheric pressure. Therefore, FIG.
The larger the value indicated by, the larger the negative pressure is introduced into the intake manifold 28. As shown in FIG. 2C, the intake negative pressure PM is rapidly increased to atmospheric pressure around time t ₀ when engine stall occurs in the internal combustion engine 10,
Time t ₁ after cranking start is started, and gradually returns to an engine stall before the occurrence of the same value.

FIG. 2D shows the timings at which fuel injection and ignition are permitted and prohibited at the internal combustion engine 10. As shown in FIG. 2 (D), in this embodiment, after the starter switch 64 is turned on at time t ₁ , until the time t ₂ at which the intake negative pressure PM reaches a predetermined negative pressure A, the fuel is Injection and ignition are prohibited. Therefore, in the process from the time t ₁ to the time t ₂ , although the cranking is performed, the internal combustion engine 10 does not experience the initial explosion.

FIG. 2E shows the sub throttle valve 38.
The change state of the opening degree of is shown. As shown in the figure,
The torque valve 38 is installed in the internal combustion engine 10 when the engine is stalled.
Occurrence time t₀Is fully closed, and the intake negative pressure PM is
Time t at which the constant negative pressure A is reached _TwoAfter that, gradually open to full
The valve is opened toward. The sub throttle 38 is as described above.
It is a valve mechanism arranged on the downstream side of the surge tank 32.
Therefore, when the sub throttle 38 is fully closed,
The intake pipe volume that communicates with the combustion chamber 20 of the fuel engine 10 is
Small enough compared to when the throttle 38 is open
It will be cheap.

An engine stall occurs in the internal combustion engine 10,
When the sub-throttle valve 38 is controlled as shown in FIG. 2 (E) when the cranking start is executed thereafter, and fuel injection and ignition are permitted or prohibited as shown in FIG. 2 (D). After the starter switch 64 is turned on, until the intake negative pressure PM reaches the predetermined value A (between times t ₁ and t ₂ ), the intake manifold 28
And the air in the combustion chamber 20 is only discharged, the internal combustion engine 1
The first explosion will not occur at 0.

Immediately after the starter switch 64 is turned on, that is, immediately after cranking is started, a large amount of air is discharged from the intake passage open to the atmospheric pressure into the combustion chamber 2.
Flows into zero. Further, under the condition that the cranking start is executed, that is, under the condition that the internal combustion engine 10 is sufficiently warmed up, the initial explosion occurs extremely easily in the internal combustion engine 10. Therefore, if the fuel injection and ignition are allowed immediately after the cranking is started, the first explosion is caused immediately after the cranking is started with a large amount of air being sucked into the combustion chamber 20. May occur. In this case, the rotational speed NE of the internal combustion engine 10 sharply increases after time t ₁ as indicated by the broken line in FIG. 2 (A), shows an overshoot that temporarily exceeds the target idle rotational speed, and then becomes steady. To a normal idle state. The curve shown by the broken line in FIG. 2 (F) shows the change state of the longitudinal acceleration (front-back G) that occurs in the vehicle when the rotational speed NE of the internal combustion engine 10 changes as described above. As shown in the figure, under such a situation, pulsation of large acceleration occurs in the front-rear direction of the vehicle, and it is difficult to maintain a comfortable riding comfort.

On the other hand, if the fuel injection and ignition are prohibited for a predetermined period after the start of cranking as described above to prevent the occurrence of the initial explosion in that period, a large torque is required during the cranking. Can be prevented, and overshoot of the rotational speed NE can be prevented. Therefore, the internal combustion engine 10 of this embodiment is
According to this, as shown by the solid line in FIG. 2 (F), a large front-rear G is not generated in the vehicle between time t ₁ and time t ₂ .

Further, in the internal combustion engine 10 of the present embodiment, after the fuel injection and ignition are started (after time t ₂ ), the sub-throttle 38 is gradually opened so that the sub-throttle 38 is sucked into the combustion chamber 20. It is intended to suppress the amount of air that is discharged. When the intake air amount is suppressed in this way, the rotational speed NE of the internal combustion engine 10 does not rise sharply even after the initial explosion occurs, and as shown in FIG. Gradually increases toward. As described above, in the internal combustion engine 10 of the present embodiment, after the cranking start is started, the NE always shows a gradual increase until the rotational speed NE reaches the target idle rotational speed. In this case, the front-rear G acting on the vehicle continues as shown by the solid line in FIG. 2F until the internal combustion engine 10 shifts to the steady idle state after the cranking start is started. Shows a relatively small and stable value.

As described above, according to the internal combustion engine 10 of this embodiment, when the cranking start is executed, the stationary state is changed to the steady idle state without applying a large front-rear G to the vehicle. Can be migrated. Hereinafter, with reference to FIG. 3 and FIG. 4, the content of the process executed by the ECU 56 in order to realize the cranking start by the above-described method will be described.

FIG. 3 shows an example of a flowchart of the main routine executed by the ECU 56. This routine is started only for a predetermined period thereafter when the engine stall occurs while the internal combustion engine 10 is sufficiently warmed up.
Specifically, the occurrence of engine stall is detected, and the cooling water temperature THW is “80 ° C. ≦ THW ≦ 10.
The condition of “0 ° C.” is satisfied, and “| TH is set between the intake air temperature THAB during engine stall and the actual intake air temperature THA.
It is activated on the condition that the condition of A-THAB | ≦ 2 ° C. ”is satisfied.

When the routine shown in FIG. 3 is started, first, at step 100, it is judged if the opening degree TA1 of the main throttle valve 42 is "0". At the start of cranking start, the throttle valve 42
Is fully closed. Therefore, when the cranking start execution request is issued, the condition of step 100 is satisfied, and thereafter the process of step 102 is executed.

At step 102, it is judged if the cranking start button 58 is turned on. As a result, if it is determined that the cranking start button 58 is turned on, the process proceeds to step 104, while if it is determined that the cranking start button 58 is not turned on, the process proceeds to step 108. In the present embodiment, if the cranking start button 58 is turned on at the start of cranking start, the execution is permitted. Therefore,
The condition of this step 102 may be unsatisfied in a period after the engine stall occurs and before the cranking start is started, and may be unsatisfied even after the cranking start is started. still,
Even if it is determined that the condition of step 102 is not satisfied before the start of cranking, step 1
Although the process after step 08 (steps 108 to 114) is executed, in this situation, since the internal combustion engine 10 is stopped, the process after step 108 is not reflected in the actual control.

When the cranking start button 58 is turned on and the condition of step 102 is satisfied, it is determined in step 104 whether the starter switch 64 is turned on. If it is determined that the starter switch 64 is on, it is determined that a cranking start execution request has been issued, and the routine proceeds to step 106. On the other hand, if it is determined that the starter switch 64 is not on, the routine proceeds to step 116.

In the present embodiment, it may be necessary to continue the processing associated with the execution of the cranking start after the starter switch 64 that was once turned on is turned off. Therefore, the condition of step 104 may be determined not to be satisfied before the starter switch 64 is turned on, and may be determined to be not satisfied after the starter switch 64 is turned from on to off. The internal combustion engine 10 remains stopped until the starter switch 64 is turned on. Therefore, in this case, the rotation speed NE should be "0". On the other hand, the starter switch 64 that has been turned on once is turned off after the internal combustion engine 10 is started. Therefore, in this case, the appropriate rotation speed NE
Should be detected.

Therefore, in step 116, the rotational speed NE
Is determined to be equal to or higher than the predetermined rotation speed α. The predetermined rotation speed α is a threshold value for determining whether the internal combustion engine 10 has an engine stall. Therefore, if the internal combustion engine 10 still has an engine stall, the condition NE ≧ α should not be satisfied. When such a determination is made, the process of step 118 is executed after step 116.

At step 118, a process of substituting "0" for the target opening MTA2 of the sub-throttle valve 38 is performed. The target opening MTA2 of the sub-throttle 38 is realized by the subroutine shown in FIG. The subroutine shown in FIG. 4 is a timed interrupt routine that is activated every predetermined time. When the routine shown in FIG. 4 is started,
First, at step 200, the actual opening TA2 of the sub-throttle valve 38 is read. Next, step 202
Then, it is determined whether or not TA2 is equal to or smaller than the target opening degree MTA2. As a result, if it is determined that TA2 ≦ MTA2 is not satisfied, the sub-throttle valve 38 is decreased by a predetermined opening degree in step 204, and then this routine is ended. On the other hand, if it is determined that TA2 ≦ MTA2 is satisfied, the sub-throttle valve 38 is increased by a predetermined opening degree in step 206, and then this routine is ended. When the routine shown in FIG. 4 is executed by the ECU 56, the opening TA2 of the sub-throttle valve 38
Is controlled to the target opening degree MTA2 by feedback control.

In the main routine shown in FIG. 3, when the process of step 118 is completed, the process of step 120 is executed next. In step 120, a process of resetting the flag XSIDO indicating whether or not fuel injection and ignition are permitted to "0" is performed. If XSIDO = 0, then
In another routine, fuel injection into the internal combustion engine 10 and ignition of fuel are prohibited. When the processing of step 120 ends, the processing of the main routine this time ends.

According to the processing of the main routine described above,
After the internal combustion engine 10 has stalled, the cranking start button 58 is turned on,
While the sub-throttle valve 38 is fully closed,
Fuel injection and ignition will be prohibited.

When the cranking start button 58 is turned on and the starter switch 64 is turned on,
In the main routine shown in FIG. 3, the condition of step 104 is satisfied. In this case, after step 104,
The process of step 106 is executed.

At step 106, it is judged if the intake negative pressure PM detected by the intake pressure sensor 36 has reached a predetermined negative pressure A or not. When it is determined that PM has not reached A yet, the process of step 118 is then executed. After that, the processes of steps 100 to 106, 118, and 120 are repeatedly executed until PM ≧ A is satisfied.

On the other hand, if it is determined in step 106 that PM has reached A, then in step 108 the fuel injection and ignition permission flag XSIDO is set to "1". When XSIDO = 1 is satisfied, fuel injection and fuel ignition are permitted by another routine. Since this processing is executed after the starter motor starts rotating, when XSIDO is set to "1" as described above, the internal combustion engine 10 immediately starts fuel injection and ignition. .

When the process of step 108 is completed, then, in step 110, a process of adding the predetermined value β to the target opening MTA2 of the sub-throttle 38 is executed. Next, at step 112, it is judged if the target opening MTA2 has reached the maximum opening MMAX. As a result, if MTA2 ≧ MMAX is not satisfied yet, the main routine is ended with the target opening MTA2 set in step 110 above as the current set value. On the other hand, already M
If TA2 ≧ MMAX is established, step 11
4, the maximum opening degree MMAX is substituted for the target opening degree MTA2, and then this routine is ended. The target opening degree MTA2 set in this way is realized by the subroutine shown in FIG.

According to the processing of the main routine described above,
The cranking start button 58 is turned on, and
When the starter switch 64 is turned on, fuel injection and ignition are started immediately thereafter, and the sub-throttle valve 38 is started every time the main routine is started.
The opening degree is gradually increased toward the maximum opening degree MMAX with the width of the predetermined opening degree β.

If the cranking start button 58 is turned off after the start of cranking start, the process of step 108 is executed after step 102 in the main routine. Also, after the cranking start is started, the starter switch 64
If is turned off, the process of step 116 is executed after step 104. If the cranking start has already been started, NE ≧ α holds. Therefore, in this case, step 108 is followed by step 108.
Is performed.

Therefore, according to this routine, once the cranking start is started, even if the cranking start button 58 or the starter switch 64 is turned off thereafter, the opening degree of the sub-throttle valve 38 will be MMAX.
The process of gradually increasing the opening degree is continued until the value reaches.

On the other hand, when the throttle valve 42 is opened after the start of cranking start,
After the main routine is started, it is determined in step 100 that TA1 = 1 is not established. In this case, after the processing of step 100, step 122 of setting "1" to the flag XSIDO and step 124 of substituting MMAX for MTA2, the main routine is ended.

Therefore, when the throttle valve 42 is opened after the cranking start is started, that is, when the acceleration request is made to the internal combustion engine 10,
Regardless of the progress of the cranking start process, fuel injection and ignition are immediately possible, and the sub-throttle valve 38 is fully opened. Therefore, according to the internal combustion engine 10, excellent acceleration characteristics can be exhibited even after the start of the cranking start and before the completion of the processing.

In the above embodiment, after the cranking start is started, until the intake negative pressure PM reaches the predetermined negative pressure A, both fuel injection and ignition are prohibited. However, the present invention is not limited to this, as long as at least one of fuel injection and fuel ignition is prohibited.

FIG. 5 shows changes in the rotational speed NE when the internal combustion engine 10 starts cranking (curve shown by a solid line in the figure), and rotational speeds when the clutch is disengaged and a normal start is performed. Change in NE (curve shown by broken line in the figure)
The characteristic diagram showing and is shown. As shown in FIG. 4, the rate of increase in NE when the internal combustion engine 10 is started by cranking start is significantly lower than the rate of increase in NE when the internal combustion engine 10 is started by normal start. .

In order to obtain the initial explosion in the internal combustion engine 10, it is desirable that the compression pressure in the combustion chamber 20 be high. Further, the compression pressure of the combustion chamber 20 becomes higher as the rotation speed NE is higher. Therefore, immediately after the start of cranking start, the internal combustion engine 10 is in a situation where it is difficult to obtain the initial explosion.

On the other hand, if the fuel is to be injected immediately after the start of cranking, the fuel will be supplied into the combustion chamber 20 under the condition that the initial explosion is difficult to obtain, and the inside of the combustion chamber 20 will be affected. May become overrich. When the inside of the combustion chamber 20 becomes overrich in this way, the number of revolutions NE increases, and even after the situation in which a high compression pressure is obtained, the situation in which the initial explosion is difficult to obtain due to the excessive supply of fuel continues. To be done. In this respect, when fuel injection is prohibited immediately after the start of cranking start as in the present embodiment, it is possible to easily start the fuel injection at the time when the rotational speed NE appropriately rises without causing the above inconvenience. You can get a blast. In this sense, the internal combustion engine 1 of the present embodiment
0 means that the engine has excellent startability as compared with a device that executes fuel injection immediately after the start of cranking start.

In the above embodiment, the ECU 56
Executes the processing of steps 118 and 120 to fully close the sub-throttle 38, whereby the intake pipe volume reducing means is realized. The ECU 5
6 executes the processing of steps 106 and 108 described above, whereby the injection ignition permission means described above performs step 1
The above-described intake pipe volume expanding means is realized by executing the processing of 10 to 114, respectively.

FIG. 6 shows an overall configuration diagram of an internal combustion engine 70 which is a second embodiment of the present invention. In FIG. 6, the same parts as those shown in FIG. 1 are designated by the same reference numerals, and the description thereof will be omitted. Internal combustion engine 10 shown in FIG.
1 is the same as the internal combustion engine 10 shown in FIG. 1 except that the intake pressure sensor 36 for detecting the intake negative pressure PM in the intake manifold 28 and the sub-throttle valve 38 arranged in the intake manifold 28 are not provided. It has a similar configuration.

The internal combustion engine 10 is a multi-cylinder internal combustion engine as described above, and the injector 34 and the spark plug 2 are provided for each cylinder.
2 is provided. Then, during normal operation, the ECU 72 supplies a fuel injection signal or an ignition signal to the injector 34 and the ignition plug 22 of each cylinder every time the rotation angle of the internal combustion engine 10 reaches a predetermined angle. As described above, if such normal operation is performed when the cranking start is performed, a large front-back G occurs in the vehicle when the internal combustion engine 70 starts.

Therefore, in the internal combustion engine 10, a part of the explosion stroke to be executed at each predetermined rotation angle is prohibited only for a predetermined period after the cranking start is started, that is, the thinning operation of the explosion stroke is performed. I am going to do it.
When the explosion strokes are thinned out, the output energy of the internal combustion engine 70 per unit time is reduced, and the energy causes the front and rear G values generated in the vehicle to be reduced. Therefore, the internal combustion engine 70 according to the present embodiment also has the internal combustion engine 1 shown in FIG.
Similar to 0, the vehicle can be started smoothly by cranking start.

Hereinafter, referring to FIG. 7 and FIG. 8, the ECU is designed to realize the cranking start by the above-mentioned method.
The contents of the processing executed by 72 will be described. FIG.
5 shows an example of a flowchart of a routine that the ECU 72 performs to determine a cranking start execution condition.

When the routine shown in FIG. 7 is started, whether the starter switch 64 is on in step 300, 4WD is selected as the drive system in step 302, or Lo mode is selected as the output torque transmission mode in step 304. Is selected.
The ECU 72 determines based on these determinations whether the vehicle is traveling off-road, that is, in a situation where it is necessary to perform a cranking start.

In step 306, in another routine, it is judged whether the deviation between the intake air temperature THAB stored when the engine stall occurs in the internal combustion engine 70 and the current intake air temperature THA is within 2 ° C. Also, in step 308,
Cooling water temperature THW "80 ° C ≤ THW ≤ 100 ° C"
It is determined whether or not the condition of is satisfied. The ECU 72
Based on these determination results, it is determined whether or not the internal combustion engine 70 has a good startability to the extent that it can be started by cranking start.

Further, at step 310, it is judged if the cranking start button 58 is turned on. The ECU 72 determines, based on the result of the determination, whether or not the driver's intention regarding performing the cranking start is displayed.

In the present routine, when all of these conditions are satisfied, the routine proceeds to step 312 to permit the execution of cranking start, sets "1" in the flag XCSTA, and then terminates this routine. On the other hand, if any of the above steps 300 to 312 is not established, this routine is terminated without performing any processing.

FIG. 8 shows an example of a flowchart of the main routine executed by the ECU 72. When the routine shown in FIG. 8 is started, first, at step 400, it is judged if the flag XCSTA is set to "1". As a result, when XCSTA = 1 is satisfied, the process of step 402 is executed.

In step 402, the starter switch 6
4 is turned on, the ignition plug 22
It is determined whether the cumulative number of times the ignition signal has been supplied to has reached a predetermined number N. As a result, if it is determined that the number of ignitions has not reached N, the process proceeds to step 404, the fuel is thinned out and the current routine is ended. On the other hand, if it is determined that the number of ignitions has already reached the predetermined number N, the process proceeds to step 406 and XCSTA
Is reset to "0", then the normal injection is executed in step 408, and then the routine of this time is ended.

The ECU 72 stores a map regarding thinned-out fuel injection as shown in Table 1 below. When executing the thinning injection shown in step 404, the ECU
72 reads the number of ignitions executed after the starter switch 64 is turned on, and searches the map shown in Table 1 below based on the number of ignitions. As a result, if "1" is displayed in the map, the current fuel injection is executed, while if "0" is displayed in the map, the current fuel injection is prohibited.

[0077]

[Table 1]

When the ECU 72 executes the routines shown in FIGS. 7 and 8, during cranking start, after the starter switch 64 is turned on, the fuel is thinned out until the number of ignitions reaches N times. It is injected, and as a result, the decimation operation for the explosion stroke is realized.

By the way, in the above embodiment, the thinning of the explosion stroke is realized by thinning the fuel injection based on the number of ignitions, but the present invention is not limited to this, and the fuel is not limited to this. It is also possible to realize the thinning of the explosion stroke by thinning the ignition based on the number of injections of. In the above embodiment, E
The CU 72 executes the processes of steps 400 to 404 to implement the explosion stroke prohibition means described above.

Next, a third embodiment of the present invention will be described with reference to FIGS. This embodiment is based on FIG.
This is realized by the ECU 72 performing a process different from the above-described routine using the hardware configuration shown in FIG. FIG. 9 shows a time chart of the fuel injection amount, the integrated amount of the injected fuel, and the rotation speed NE when the internal combustion engine 70 is started in the normal mode. FIG. 9A shows the timing at which fuel is injected into one of the cylinders after the start of cranking and the fuel injection amount at that time. The fuel injection is performed every time the internal combustion engine 70 rotates by a predetermined rotation angle. Therefore, the fuel injection interval is shortened as the rotational speed NE increases with the elapse of time t, as shown in FIG. 9 (A).

For example, at the time of cold start, the internal combustion engine 7
In order to properly start 0, it is preferable to make the air-fuel ratio in the combustion chamber 20 fuel rich. On the other hand, the combustion chamber 20
If an excessive amount of fuel is supplied into the internal combustion engine 70, a phenomenon in which the spark plug 22 does not properly generate sparks, that is, a so-called fogging phenomenon occurs, and the startability of the internal combustion engine 70 may be impaired. Therefore, the fuel injection amount at the time of normal start-up is shown in FIG. 9A in order to avoid an excessive rich state in the combustion chamber 20 when cranking is prolonged.
As shown in, the dose is reduced over time.

FIG. 9B shows the integrated value of the injected fuel when the fuel injection is performed as shown in FIG. 9A. Since the fuel injection is performed in pulses, the integrated amount is shown in FIG.
It shows a gradual increase as shown in (B). In the figure,
The hatched area indicated by indicates the integrated amount of fuel injected by time t ₁ after the cranking is started at time t ₀ , and the area indicated by indicates the time from t ₁ to t _2.
It shows the cumulative amount of fuel injected up to.

FIG. 9C shows the rotational speed NE of the internal combustion engine 70 after the cranking is started. The curve indicated by the broken line in the figure shows the change in the rotational speed NE when the first explosion is obtained in the internal combustion engine 70 relatively early after the cranking is started at time t ₀ and at time t ₁ . Further, the curve shown by the solid line in the figure requires a relatively long cranking period, and the number of revolutions N when the initial explosion is obtained in the internal combustion engine 70 at time t _2.
The change in E is shown.

A part of the fuel injected before the initial explosion occurs in the internal combustion engine 70 adheres to the intake port of the internal combustion engine 70, the inner wall of the combustion chamber 20 and the like, and the rest of the fuel flows from the exhaust port to the exhaust manifold 30. Blows through. The time-dependent reduction of the fuel injection amount shown in FIG. 9 (A) is set so that the air-fuel ratio in the combustion chamber 20 finally becomes an appropriate fuel rich state in consideration of such fuel blow-through. Is desirable.

When the fuel injection amount at the time of starting the internal combustion engine 70 is set as described above, the air-fuel ratio in the combustion chamber 20 becomes
As the cranking period is prolonged, the fuel rich state is approached. Therefore, in the example shown in FIG. 9, the air-fuel ratio in the combustion chamber 20 at the time t ₂ is more fuel rich than the air-fuel ratio in the fuel chamber 20 at the time t ₁ due to the fuel shown in the region. It means that it has been made.

At the time of starting the internal combustion engine 70, inside the combustion chamber 20
The larger the amount of fuel burned, the greater the output torque generated.
It is. Therefore, in the example shown in FIG. 9, the internal combustion engine 70
Is time t₁If it starts at a relatively low output torque
Occurs at the time t _TwoIf started to
A relatively large output torque will be generated.

As described above, in order to obtain good startability in the internal combustion engine 70, when it is attempted to converge the air-fuel ratio in the combustion chamber 20 at the time of starting to a predetermined fuel rich state, the first explosion from the start of cranking. The output torque at the time of starting the internal combustion engine 70 varies depending on the time required to obtain. Therefore, when the cranking start is executed by using such setting as it is, when the first explosion is obtained in the internal combustion engine 70 immediately after the start of the cranking start, the front-rear G acting on the vehicle is small, but If it takes a relatively long time from the start of ranking to the first explosion, a large front and rear G
Will be inconvenient.

The present embodiment is characterized in that such inconvenience is eliminated by making the setting of the fuel injection amount at the time of normal start-up different from the setting of the fuel injection amount at the time of cranking start. ing. The above function
The ECU 72 is realized by executing the routines shown in FIGS. 10 and 11.

FIG. 10 shows an example of a flowchart of a subroutine executed by the ECU 72 to determine the traveling mode of the vehicle. When the routine shown in the figure is started, first, at step 500, it is judged if 4WD is selected as the drive system. Next, at step 502, it is judged if the Lo mode is selected as the power transmission mode. Next, at step 504, it is judged if the ON signal is inputted from the cranking start button 58.

As a result of these judgments, if all the conditions are satisfied, the vehicle is traveling off-road, and
It is judged that execution of cranking start is required. In this case, in step 506, the flag XCSTA that permits execution of cranking start is set to "1", and then this processing is ended. On the other hand, if any of the conditions in steps 500 to 504 is not satisfied, it is determined that the cranking start is not required to be executed. In that case, after the flag XCSTA is reset to "0" in step 508, the process this time is ended.

In the routine shown in FIG. 10, the cooling water T
Although the condition regarding HW and the condition regarding intake air temperature THA are not included, step 3 in the routine shown in FIG.
Conditions similar to 06 and 308 may be incorporated. FIG.
Shows an example of a flowchart of a routine that the ECU 72 executes to calculate a fuel injection amount. When the routine shown in FIG. 11 is started, first in step 600,
It is determined whether or not the starter switch 64 is turned on. As a result, if it is determined that the starter switch 64 is not turned on, then in step 624, the fuel injection amount calculation mode after starting is executed, and then this routine is ended. On the other hand, starter switch 6
If it is determined that 4 is turned on, step 6
Go to 02.

At step 602, it is judged if the rotational speed NE of the internal combustion engine 70 is less than a predetermined value. as a result,
If NE <predetermined value is not already satisfied, the internal combustion engine 70
Is determined to have been started, and thereafter, the process proceeds to step 624. On the other hand, if it is determined that NE <predetermined value is satisfied, the routine proceeds to step 604, where it is judged if the starter switch 64 has already been turned on in the previous processing.

As a result, if it is determined that the starter switch 64 was not turned on in the previous processing, the routine proceeds to step 606, where the timer built in the ECU 72 is cleared. On the other hand, if the starter switch 64 has already been turned on and it is determined to be an attacker in the previous processing,
The process jumps from step 606 to directly proceed to step 608. The timer is configured to automatically start counting up after being cleared. Therefore, the value of the timer always indicates the elapsed time after the starter switch 64 is switched from off to on.

In step 608, calculation of the fuel injection amount TAU is executed. TAU is the intake air amount, intake air temperature TH
A value capable of imparting good startability to the internal combustion engine 70 is calculated by a known method based on A, the cooling water temperature THW, the rotational speed NE, and the like. After the calculation of TAU is completed, the routine proceeds to step 610, where it is judged if the flag XCSTA is set to "1". As a result, XCST
When A = 1 is not established, it is determined that the cranking start is not required to be executed, that is, the normal start is required, and the routine proceeds to step 622, where the actual injection amount TAUINJ is set. Substituting the TAU obtained in step 608 above, the processing of this time is ended.

On the other hand, if it is determined in step 610 that XCSTA = 1 holds, then, in step 612, it is estimated that TAU adheres to the vicinity of the intake port when injected, in accordance with the arithmetic expression A = TAU × γ. The amount of fuel to be discharged (hereinafter, referred to as port adhesion amount A) is calculated.
The coefficient γ is a ratio of fuel adhering to the intake port or the like when fuel injection is performed in an environment in which cranking start is executed, that is, in an environment in which the internal combustion engine 70 is sufficiently warmed up. It is a value obtained experimentally. γ can be set not only as a constant but also as a function of THA and THW.

After the calculation of the port adhesion amount A is completed, the routine proceeds to step 614, where the integrated value B of the port adhesion amount A is calculated. The integrated value B is the value B calculated in the previous processing.
It can be obtained by adding A _-1 obtained in step 612 in this processing to _i-1 . After the above processing is completed, the routine proceeds to step 616, where it is determined whether the timer has exceeded a predetermined value, that is, whether the predetermined time has elapsed after the starter switch 64 was turned on. If the result is that timer> predetermined value holds, then step 6
Step 18 is executed. At step 618, it is judged if the integrated value B of the port adhesion amount exceeds a predetermined value. As a result, if B> predetermined value holds, then the process of step 620 is executed.

On the other hand, if either of the conditions of step 616 and step 618 is not satisfied, step 620 is jumped and step 622 is executed. In this case, in step 622, XCSTA = 1
Similarly to the case where is not established, the TAU obtained in step 608 is set as the actual injection amount TAUINJ.

At step 620, TAU ′ = TAU ×
According to the equation (1-γ), the amount of fuel that does not adhere to the intake port and the like when TAU is injected, that is, the amount of fuel that blows through the exhaust port TAU 'is calculated.
After the calculation of TAU 'is completed, the routine proceeds to step 622, where the actual injection amount TAUINJ is set. In this case, T
For AUINJ, TAU ′ obtained in step 620
Is set.

As described above, TAU 'is the amount of fuel blown through the intake chamber 20 and discharged from the exhaust port. Therefore, even if TAU 'is supplied, the amount of fuel adhered in the vicinity of the intake port and in the combustion chamber 20 is not increased. Therefore, according to this routine 22, when a cranking start execution request is made, timer> predetermined value,
And B> predetermined value are both established, the fuel adhesion amount B in the vicinity of the intake port is increased over time as in the case of a normal start, but both timer> predetermined value and B> predetermined value are established. After that, cranking is continued without further increase of B.

Further, in this embodiment, the convergence value of the fuel adhesion amount B (predetermined in step 618 above) is set so that the inside of the combustion chamber 20 is in a predetermined fuel lean state even when the cranking is prolonged. Value) is set. Therefore, according to the internal combustion engine 70 of the present embodiment, there is no difference in the air-fuel ratio when the initial explosion occurs in the internal combustion engine 70 due to the length of the cranking period. Can be started.

In the above embodiment, the ECU 72
By executing the processing of steps 612 and 614,
The predetermined integrated amount detecting means is realized by executing the process of 18, and the fuel injection amount controlling means is realized by executing the processes of steps 620 and 622, respectively.

By the way, in the above embodiment, it is determined whether or not the reduction of the actual injection amount is started based on whether or not the integrated value B of the intake port adhesion amount A has reached a predetermined value. However, the present invention is not limited to this. That is, the integrated value B of the intake port adhesion amount A is a function of the integrated value of the fuel injection amount TAU. Therefore, the determination of whether B has reached the predetermined value is equivalent to the determination of whether the integrated amount of the fuel injection amount TAU after the start of cranking has reached the predetermined value. Therefore, whether or not to reduce the actual injection amount may be determined based on whether or not the integrated amount of the fuel injection amount TAU has reached a predetermined value.

Next, in the internal combustion engine 70, an appropriate IS
The contents of the control executed by the ECU 72 to realize the C control will be described. The internal combustion engine 70 includes the bypass passage 46 that bypasses the throttle valve 42 as described above, and the ISCV 48 that controls the conduction state of the bypass passage. With this configuration, when the throttle valve 42 is fully closed, the internal combustion engine 70 is supplied with an amount of air according to the opening degree of the ISCV 48. Therefore, the idle speed of the internal combustion engine 70 can be controlled by controlling the opening degree of the ISCV 48.

The control of the ISCV 48 is performed by feedback control based on the deviation between the rotational speed NE of the internal combustion engine 70 and the target idle rotational speed. In addition, the ECU 72
Performs feedback control of the ISCV 48 and stores the ISCV opening at which the target idle speed is realized as a learning value at any time. The learning value stored in this way is
It is used as an initial value of the ISC opening when the internal combustion engine 70 is stopped and restarted. As a result of such control, the internal combustion engine 70 achieves the target idle speed immediately after starting.

By the way, when the vehicle is traveling on an off-road such as a rugged road or a rocky road, a large resistance acts on the wheels as compared with the normal traveling. Further, in such a situation, the brake operation is performed more frequently than during normal traveling. Furthermore, when 4WD is selected as the drive system and Lo mode is selected as the power transmission mode,
Compared to the case where the 2WD or Hi mode is selected, a large loss occurs in the power transmission process. Therefore, the ISC opening required to obtain the target idle speed during off-road traveling is larger than the ISC opening required during normal traveling. Therefore, if the learning value of the ISC opening is updated during off-road running, the value becomes larger than the ISC opening required during normal running, and the target idle rotation speed is restored when returning to normal running. Occasionally, a number cannot be obtained.

FIG. 12 shows an ECU for eliminating such a bad effect.
An example of an ISC control routine executed by 72 is shown. FIG.
When the routine shown in FIG. 2 is started, first, at step 700, various correction terms required for the calculation of the ISC opening degree, that is, the correction terms for the cooling water temperature THW, the intake air temperature THA, etc. are calculated.

Next, at step 702, the flag XCS is set.
It is determined whether TA is set to "1", that is, whether the vehicle is traveling off-road. When it is determined that XCSTA = 1 is not established as a result of the determination, the process proceeds to step 704, and the deviation between the actual rotation speed NE and the target idle rotation speed and the above-mentioned step 700.
The ISC opening for achieving the target idling speed is calculated based on the various correction terms calculated in step 1. Then, in step 706, the learned value of the ISC opening is updated and the routine of this time is ended. On the other hand, in step 702, XCST
If A = 1 is satisfied, that is, if it is determined that the vehicle is traveling off-road, steps 704 and 706.
This routine is ended without performing the process of.

According to the above routine, the feedback control of the ISC opening and the update of the learning value are executed only when the vehicle is normally traveling, and are not performed during off-road traveling. According to such a configuration, the learned value of the ISC opening will not be unduly updated during off-road traveling.

As in this example, the IS is
When the learned value of the C opening is prevented from becoming a large value, it is possible to prevent over-idling when the vehicle returns to normal traveling, and also to prevent the internal combustion engine 70 from traveling during off-road traveling. It is possible to prevent a large output torque from being generated when the internal combustion engine 70 is started when the engine stall occurs and then the cranking start is executed. In this respect, the internal combustion engine 70 of the present embodiment has excellent effects both in preventing over-idling during normal traveling and ensuring smooth cranking start performance.

FIG. 13 shows a second example of the ISC control routine executed by the ECU 72. When the routine shown in FIG. 13 is started, first, at step 800, it is judged if the starter switch 64 is off. If it is determined that the starter switch 64 is off, then the process of step 802 is executed.

In step 802, as in step 700 shown in FIG. 12, various correction terms required for calculating the ISC opening are calculated. When the calculation of the correction term is completed, step 804 determines whether the flag XCSTA has changed from "0" to "1" from the previous processing to the current processing. As a result, when it is determined that XCSTA has changed from “0” to “1”,
It is determined that the traveling mode of the vehicle has changed from the normal traveling mode to the off-road traveling mode, and the learning value K ₀ of the ISC opening at that time is stored. On the other hand, if it is determined that XCSTA has not changed from “0” to “1”, step 806 is skipped and the process proceeds to step 808.

In step 808, the ISC opening is calculated in the same manner as in step 704 shown in FIG.
When this calculation is completed, the process of step 810 is executed next. In step 810, the process of calculating the learned value of the ISC opening is performed as in step 706 shown in FIG. Thereafter, in step 812, the learning value calculated this time is stored as K ₁ , and then step 814.
The ISC opening degree realized by is stored and the processing of this time is ended.

As described above, according to this routine, the XCS
Even after TA is set to 1, that is, after the vehicle driving mode is changed to the off-road driving mode, ISCV
The feedback control of is continuously executed. Therefore,
When the ECU 72 executes this routine, it is possible to realize a stable idle rotation speed during off-road traveling and obtain high engine stall resistance.

Further, when the ECU 72 executes this routine, when the internal combustion engine 70 is started, the starter switch 64 is turned on and the above step 8 is performed.
The condition of 00 is not satisfied, and thereafter, the processes of step 816 and thereafter are executed. In step 816, the flag XC
It is determined whether the STA is "1". When the vehicle is traveling off-road and the driver has requested the cranking start, XCSTA is determined to be "1". In this case, the process of step 814 is executed through step 818 after step 816.
In this case, in step 818, the ISC opening, learning value K ₀ was stored in step 806, i.e., the vehicle is set learning value K ₀ stored at the time of switching to off-road driving mode from the normal driving mode It According to this routine, the learning value updated during off-road traveling is not reflected on the ISC opening when executing the cranking start. Therefore, according to this routine, it is possible to prevent an unnecessarily large ISC opening degree from being set at the start of cranking, and the vehicle can be smoothly started by the start of cranking.

On the other hand, in step 816, the XCS
If it is determined that TA = 1 is not satisfied, that is, if the internal combustion engine 70 is requested to start normally, the process of step 814 is executed via step 820. At this time, in step 820, ISC
At the opening, the learning value K ₁ stored in step 812 is stored.
Is set. The learning value K ₁ is the latest learning value at the time when the vehicle is started. Therefore, when such a setting is made, the internal combustion engine 10 can achieve the target idle speed promptly after starting.

As described above, according to this routine, the cranking start is performed while the feedback control of ISCV is performed not only when the vehicle is traveling in a normal state but also when the vehicle is traveling off-road. Thus, the vehicle can be started smoothly. Therefore, according to this routine, it is possible to achieve both smooth cranking start and excellent engine stall resistance.

Next, the contents of the control executed by the ECU 72 in the internal combustion engine 70 to realize appropriate ignition timing control will be described. It is known that in order to obtain high combustion efficiency in the internal combustion engine 70, it is advantageous to set the ignition timing to the advance side within a range where knocking does not occur. Therefore, in the internal combustion engine 70, when a normal start is executed, the ignition timing is set at a timing giving priority to the ignitability of fuel during cranking, and the ignition timing is gradually increased after the initial explosion is obtained. Control is performed to change to the advance side.

By the way, after the internal combustion engine 70 is started,
When the ignition timing is advanced, the output torque generated by the internal combustion engine 70 increases as the ignition timing advances. Therefore, if the advance angle control is executed at the time of cranking start, a large torque fluctuation occurs when the vehicle starts,
Unpleasant longitudinal acceleration will occur. In particular, when the cranking start is executed, the Lo mode, which has a high torque transmission efficiency to the drive wheels, is selected as the power transmission mode of the vehicle, so that the output torque fluctuation of the internal combustion engine 70 is large in the vehicle. Give behavior change.

From this point of view, it is desirable that the ignition timing is advanced at the time of cranking start as gently as possible. FIG. 14 shows a flowchart of an example of a routine executed by the ECU 72 to satisfy the above requirements. When the routine shown in FIG. 14 is started, first, in step 900, the flag XCSTA is set to "1".
Is set. As a result, XCS
If TA = 1 is not established, then steps 902 to
908 is jumped, and the process of step 910 is executed. In step 910, the maximum value MAX that can be set as the ignition timing is substituted for the ignition timing θ _A that is set when the cranking start execution request is made.

On the other hand, when XCSTA = 1 holds,
At step 902, it is judged if the starter switch 64 is turned on. Starter switch 6
If it is determined that No. 4 is turned on, it is determined that execution of cranking start is requested, and the process further proceeds to step 904.

In step 904, the starter switch 6
It is determined whether 4 has been switched from off to on from the previous processing to the current processing. As a result, when it is determined that the power is switched from off to on, it is determined that the cranking start execution request has just been issued,
Proceed to step 906. In step 906, a preset initial value “0” is substituted for the ignition timing θ _A used when executing cranking start.

On the other hand, if it is determined in step 904 that the starter switch 64 has not just been switched from off to on, and if it is determined in step 902 that the starter switch 64 is no longer on, In step 908, the ignition timing θ _A at the time of executing the cranking start is advanced by the predetermined angle δ.
Here, the predetermined angle δ is a sufficiently small value that is set so that large torque fluctuation does not occur when the vehicle starts.

Step 906, 908, or 9 described above
When the process of 10 is completed, the process of step 912 is executed next. In step 912, the ignition timing θ _B that should be set during normal operation is calculated. θ _B is the internal combustion engine 7
It is a value set for the purpose of obtaining a high combustion efficiency at 0, and after the internal combustion engine 70 is started, it is advanced promptly until a time when a high combustion efficiency is obtained.

After calculating the ignition timing θ _B , step 914
Then, it is determined whether or not θ _A ≧ θ _B holds. A cranking start execution request is issued, and step 9 above
When the processing of 06 or 908 is executed, the above condition is satisfied. In this case, thereafter, after the ignition timing θ _A is stored in step 918, this routine is ended.
On the other hand, if the cranking start execution request has not been issued and the process of step 910 has been executed, the above condition is not satisfied. In this case, thereafter, after the ignition timing θ _B is substituted for the ignition timing θ _A in step 916, the process of step 918 is executed.

According to the above-mentioned routine, when the internal combustion engine 70 is started by cranking start, the ignition timing is advanced very gently after the cranking is started. Therefore, the internal combustion engine 7 is controlled by the advance control.
The torque fluctuation occurring at 0 is small, and the vehicle can be smoothly started by cranking start. On the other hand, when the internal combustion engine 70 is started in the normal starting mode,
The ignition timing is advanced immediately after the internal combustion engine 70 is started, and high combustion efficiency can be obtained immediately after the startup.

[0126]

As described above, according to the first aspect of the present invention, at the start of cranking start, the initial explosion can be generated in the internal combustion engine with a sufficiently small intake air amount. Further, after a predetermined time after the start of cranking, the output torque of the internal combustion engine can be gradually increased as the volume of the intake pipe is increased. Therefore, according to the cranking start control device of the present invention, it is possible to smoothly start the cranking of the vehicle without suddenly changing the drive torque transmitted to the drive wheels.

According to the second aspect of the present invention, at the start of cranking, the explosion stroke of the internal combustion engine can be thinned out. In this case, the output torque fluctuation becomes gentle while the internal combustion engine changes from the stopped state to the steady idling state. Therefore, the cranking start control device according to the present invention also provides the above-mentioned claim 1.
Similar to the described device, the vehicle can be smoothly cranked and started without suddenly changing the driving torque transmitted to the driving wheels.

Further, according to the third aspect of the present invention, during the cranking start, regardless of the length of time required for the internal combustion engine to start, the amount of fuel adhering to the wall surface during the cranking execution, that is, The amount of fuel burned when the initial explosion occurs in the internal combustion engine can be kept substantially constant. Therefore, according to the cranking start control device of the present invention, not only when the internal combustion engine can be started for a short period of time, but also when the internal combustion engine takes a long time to start, the transmission to the drive wheels is performed. The vehicle can be cranked smoothly without suddenly changing the driving torque.

[Brief description of drawings]

FIG. 1 is an overall configuration diagram of an internal combustion engine that is a first embodiment of the present invention.

FIG. 2 is a time chart for explaining the operation of the internal combustion engine that is the first embodiment of the present invention.

FIG. 3 is an example of a flowchart of a routine that is executed to realize a smooth cranking start in the first embodiment of the present invention.

FIG. 4 is an example of a flowchart of a routine that is executed to control the sub throttle in the first embodiment of the present invention.

FIG. 5 is a diagram showing a rotational speed increasing characteristic at the time of starting the internal combustion engine which is the first embodiment of the present invention.

FIG. 6 is an overall configuration diagram of an internal combustion engine that is a second and a third embodiment of the present invention.

FIG. 7 is an example of a flowchart of a routine that is executed to determine a cranking start execution condition in the second embodiment of the present invention.

FIG. 8 is an example of a flowchart of a routine that is executed to realize a smooth cranking start in the second embodiment of the present invention.

FIG. 9 is a time chart for explaining the content of fuel injection control performed at the time of normal starting.

FIG. 10 is a flowchart of a routine executed to determine a cranking start execution condition in the third embodiment of the present invention.

FIG. 11 is an example of a flowchart of a routine that is executed to realize a smooth cranking start in the third embodiment of the present invention.

FIG. 12 is an example of a flowchart of an ISC control routine that is executed to realize a smooth cranking start.

FIG. 13 is another example of a flowchart of an ISC control routine executed to realize a smooth cranking start.

FIG. 14 is an example of a flowchart of an ignition timing advance control routine executed to realize a smooth cranking start.

[Explanation of symbols]

10, 70 Internal combustion engine 20 Combustion chamber 22 Spark plug 28 Intake manifold 30 Exhaust manifold 34 Injector 36 Intake pressure sensor 38 Sub-throttle valve 42 Main throttle valve (throttle valve) 48 Idle speed control valve (I
SCV) 56,72 Electronic control unit (ECU) 58 Cranking start button 60 4WD / 2WD selector switch 62 Hi / Lo selector switch 64 Starter switch 66 NE sensor

─────────────────────────────────────────────────── ─── Continuation of the front page (51) Int.Cl. ⁶ Identification code Internal reference number FI Technical display location F02N 11/08 F02N 11/08 F 17/00 17/00 B F02P 5/15 F02P 5/15 E

Claims (3)

[Claims] 1. A cranking start control device for changing an internal combustion engine, which is directly connected to drive wheels of a vehicle, from a stopped state to a started state, wherein an intake pipe for reducing a volume of an intake pipe of the internal combustion engine at the start of cranking start. Volume reduction means, injection and ignition permission means for permitting execution of both fuel injection and fuel ignition when the internal pressure of the intake pipe reaches a predetermined negative pressure, and at a predetermined time after the start of cranking, A cranking start control device comprising: an intake pipe volume expanding means for expanding the volume of the intake pipe. 2. A cranking start control device for changing an internal combustion engine directly connected to driving wheels of a vehicle from a stopped state to a started state, wherein a part of an explosion stroke of the internal combustion engine to be executed at every predetermined timing is A cranking start control device comprising an explosion stroke prohibiting means for prohibiting cranking. 3. A cranking start control device for changing an internal combustion engine, which is directly connected to driving wheels of a vehicle, from a stopped state to a started state, an injection fuel integrating means for integrating fuel injected during a cranking period, Predetermined integrated amount detecting means for detecting that the integrated amount of injected fuel reaches a predetermined value during the cranking period, and the internal combustion engine after the integrated amount of injected fuel during the cranking period reaches the predetermined value. And a fuel injection amount control means for controlling the fuel injection amount so that the amount of fuel adhered to the inner wall of the engine is constant, and a cranking start control device.