JP2000097098A - Noise reducing device for driving system - Google Patents

Abstract

PROBLEM TO BE SOLVED: To reduce noise emission from a drive system generated in association with variation of engine revolutions by suppressing the variation in the specific operating region such as idling. SOLUTION: The generated current value of an alternator 10 is dropped by an alternator control means 25 if an operating region judging means 21 judges that the operation of an internal-combustion engine is in a specific noise emissive operating region and in case the variation in the engine revolutions sensed by a revolutional variation sensing means 22 is over a specified level, and the revolutional variation of the engine is suppressed by reducing the external load of the engine associated with the drive of alternator 10 or reducing the exhaust gas circulation amount by an EGR control means 26.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a device for reducing abnormal noise of a drive system caused by fluctuations in engine rotation in a specific operating region such as idling, and more particularly, to a direct injection type to which a manual transmission is connected. The present invention relates to a drive system abnormal noise reduction device suitable for an internal combustion engine.

[0002]

2. Description of the Related Art Internal combustion engines (engines) for vehicles such as automobiles and trucks are usually four-stroke engines, and each process of intake, compression, expansion and exhaust is performed in one operation cycle. In the four-stroke engine, the output is obtained in the expansion stroke, while the compression stroke is used to compress the intake air drawn into the combustion chamber. For this reason, the rotation of the engine is accelerated in the expansion stroke, and is decelerated in the compression stroke by a load accompanying the compression, and the engine rotation fluctuates in a minute cycle. Therefore, a flywheel is mounted on the engine, and rotation fluctuation can be suppressed to some extent by inertial force of the flywheel and the like.

[0003]

However, when the engine is rotating at a high speed, the effect of the inertia force of the flywheel or the like is large, so that the load caused by the compression and the explosion affects the rotation of the engine. Although almost negligible, when the engine is running at a low speed, especially when idling, the effect of the inertia force of the flywheel etc. on reducing the rotational fluctuation is reduced, so the load on the engine running due to compression and explosion is relatively small. It becomes big.

In particular, in a direct injection type engine in which fuel is directly injected into a combustion chamber, lean operation by stratified combustion in which the air-fuel ratio is extremely leaner than the stoichiometric air-fuel ratio is possible. Since a very large amount of air is sucked in and this large amount of intake air is compressed, the compression pressure during the compression stroke, that is, the load on the engine is also larger than that of a normal MPI engine. For this reason,
As shown in FIG. 8A, the fluctuation of the engine rotation during idling is larger in the in-cylinder injection type engine than in the normal MPI engine.

[0005] The influence of the fluctuation of the engine rotation naturally affects devices and driving systems connected to the engine. In particular, in a manual transmission (M / T), a gear rattling noise may be generated at a gear meshing portion due to fluctuations in engine rotation. When a load (external load) for driving a device connected to the engine is large, the torque to be generated by the engine to keep the engine rotation constant during idling also increases. As shown in (b), the fluctuation of the rotation of the engine also increases. That is, the possibility that rattling noise is generated from the M / T increases. Further, during the EGR operation, the compression work of the engine increases, so that the fluctuation of the engine rotation tends to be large. In this case also, the possibility that the M / T generates rattling noise increases.

[0006] Such rattling noise is inconspicuous when the vehicle is running, but becomes noticeable when the vehicle is stopped, which tends to cause discomfort to the occupants of the vehicle and impair the texture of the vehicle. Therefore, it is necessary to suppress fluctuations in engine rotation during idling and to reduce abnormal noise such as rattling noise generated from the drive system such as the M / T. The present invention has been made in view of such a problem, and suppresses abnormal noise of a drive system generated due to engine rotational fluctuation by suppressing engine rotational fluctuation in a specific operating region such as idling. It is an object of the present invention to provide a drive system abnormal noise reduction device that can be used.

[0007]

For this reason, in the drive system abnormal noise reduction device according to the present invention, the operating region determining means determines that the operating region of the internal combustion engine is in a specific noise generating operating region. And, when the rotation fluctuation amount of the internal combustion engine detected by the rotation fluctuation amount detecting means is equal to or more than a predetermined value,
The generator current value of the alternator is reduced by the alternator control means.

[0008] Thus, the external load of the internal combustion engine due to the drive of the alternator is reduced, and the rotation fluctuation of the internal combustion engine in a specific operation region is suppressed. In the drive system abnormal noise reduction device according to the second aspect of the present invention, the operation region of the internal combustion engine is determined to be in a specific noise generating operation region by the operation region determination unit, and is detected by the rotation fluctuation amount detection unit. If the rotation fluctuation amount of the internal combustion engine is equal to or more than a predetermined value,
The exhaust gas recirculation amount of the EGR means is reduced by the EGR control means.

As a result, the factor for increasing the compression work by the EGR means is reduced, and the rotation fluctuation of the internal combustion engine in a specific operating region is suppressed.

[0010]

Embodiments of the present invention will be described below with reference to the drawings. FIGS. 1 to 7 show a drive system abnormal noise reduction device according to an embodiment of the present invention. First, FIG. 2 will be described. FIG. 2 shows an engine to which the drive system abnormal noise reduction device is applied. It is a figure which shows the structure of (internal combustion engine) typically. The engine to which the present drive train abnormal noise reduction device is applied is an engine (not shown) to which a manual transmission (M / T) is connected, and will be described below on the assumption that the engine has an M / T.

The engine 1 is configured as an in-cylinder injection type engine that directly injects fuel into a combustion chamber. For example, premixed combustion or compression by injecting fuel at a timing centering on an intake stroke is performed. The stratified combustion can be performed by injecting the fuel at a timing centered on the stroke, and when the engine output demand is large (the engine speed is large and the engine load is large), the air-fuel ratio is set to the stoichiometric air-fuel ratio or the theoretical air-fuel ratio. When premixed combustion operation (stoichiometric operation, rich operation) richer than the air-fuel ratio is performed and the engine output demand is small (the engine speed is small and the engine load is small), the air-fuel ratio is made leaner than the stoichiometric air-fuel ratio. Premix combustion operation (lean operation) and stratified combustion operation (lean operation) that is extremely leaner than the stoichiometric air-fuel ratio are performed. When idling, lean operation is performed by this stratified combustion.

At the time of lean operation by the stratified combustion, air-fuel ratio control, fuel control, and ignition control are performed. At this time, the target air-fuel ratio is set extremely large, while the throttle opening is small (engine load is low). Small),
In order to achieve the target air-fuel ratio and the target fuel injection amount, the amount of intake air is insufficient. Therefore, a bypass 12 is provided around the portion of the intake passage 3 having the throttle valve 14, and a large amount of intake air is supplied into the combustion chamber 2 via the bypass 12.

The bypass passage 12 is provided with a flow regulating valve (air bypass valve) 13. The ECU 20 controls the fuel injection valve 8 and the ignition plug 37, as well as the engine speed detected by the crank angle sensor 9 and the throttle valve 1 detected by the throttle position sensor 15.
4 and the air cleaner 1 in the intake passage 3.
6, a target air-fuel ratio, a target fuel injection amount, a fuel injection timing, and an ignition timing based on intake air amount information detected by an air flow sensor 17 provided downstream of the engine 6 and other engine load parameters (oil temperature, water temperature, etc.). The timing is set, and the opening degree of the air bypass valve 13 is also controlled.

The engine 1 is provided with an EGR (EGR means) 6 which is an exhaust gas recirculation device. Part of the exhaust gas exhausted from the combustion chamber 2 to the exhaust passage 4 is E
The fuel is returned to the intake passage 3 via the GR 6, slows down the combustion in the combustion chamber 2, lowers the maximum combustion temperature, and reduces NO in the exhaust gas.
x is reduced. The EGR 6 is provided with an exhaust gas recirculation valve (EGR valve) 7.
Controls the amount of exhaust gas recirculation by controlling the opening of the EGR valve 7.

An alternator 10 receives the rotation of the crankshaft 5 via a V-belt 11 wound around a pulley (not shown).
The electricity generated by the alternator 10 is the battery 1
8 and is used when the engine is started or when the lamps are turned on. Incidentally, the alternator 10 is driven by the rotational force of the engine as described above, and is one of the external loads of the engine. Therefore, when the load resistance of the alternator 10 at the time of power generation is large, the rotation of the engine at the time of idling is varied, and abnormal noise is generated from a drive system (not shown) such as an M / T.

When the exhaust gas is recirculated by the EGR 6, the amount of air taken into the combustion chamber 2 increases by the amount of the recirculated exhaust gas, so that the compression pressure during compression increases. For this reason, the compression work of the engine 1 increases, and the engine rotation increases during idling. Further, the amount of exhaust gas recirculation is adjusted by controlling the opening of the EGR valve 7. However, this opening control may vary, and the exhaust gas pressure is not always constant. Therefore, the amount of exhaust gas to be recirculated fluctuates.
Therefore, the compression work of the engine 1 also changes due to these factors, and the fluctuation of the engine rotation varies.

As described above, the power generation by the alternator 10 and the recirculation of exhaust gas by the EGR 6 cause fluctuations in engine rotation during idling, and cause abnormal noise from a drive system such as an M / T. However, since the electricity charged in the battery 18 is also used during idling, the alternator 1 is operated even during idling.
In many cases, power generation by zero is necessary. In addition, the recirculation of exhaust gas by the EGR 6 is useful for reducing the amount of NOx emission, and the necessity of reducing the amount of NOx emission does not change during idling.

Therefore, the present drive train abnormal noise reduction device is configured as follows in order to suppress fluctuations in engine rotation due to these effects without impairing the purpose of power generation by the alternator 10 and recirculation of exhaust gas by the EGR 6. ing. That is, as shown in FIG. 1, the present driveline abnormal noise reduction device detects fluctuations in engine rotation during idling based on input signals from the crank angle sensor 9, the throttle position sensor 15, the battery 18, and the idle switch 19. The ECU 20 controls the voltage regulator 10A and the EGR valve 7 in the alternator 10 by the ECU 20. The ECU 20 includes idling determination means (operation area determination means) 2 as its functional elements.
1, rotation fluctuation amount detection means 22, mode selection means 23, abnormal noise reduction control determination selection means 24, alternator control means 2
5, EGR control means 26 is provided.

First, the idling determining means 21
Based on the input signal from the dollar switch 19, the engine 1
Whether the vehicle is in a specific operating area,
This is a means for determining whether or not the vehicle is in a standby state. Idols
The switch 19 is attached to the throttle position sensor 15.
And the throttle valve 14 is at the idle opening.
Input to the idling determination means 21
It is designed to help. And the idle switch 1
9 when the detection signal is input from the
Stage 21 determines that engine 1 is idling.
It is supposed to. In addition, the judgment of the idling state
In addition to using the idle switch 19,
Speed V (V ≦ small threshold) and engine speed Ne (N_e1≤
Ne ≦ N _e2) May be determined.

The rotation fluctuation detecting means 22 detects the fluctuation ΔNe of the engine rotation based on the input signal from the crank angle sensor 9. The crank angle sensor 9 detects the position of the crankshaft 5 with respect to the compression top dead center, and the detection signal is input to the rotation fluctuation detecting means 22. The rotation fluctuation detecting means 22 first detects the fluctuation ΔNe based on the time interval at which the detection signal is generated.

The mode selection means 23 determines the engine speed N
This is means for selecting one of the above modes (stoichiometric operation, rich operation, lean operation by stratified combustion, lean operation by premixed combustion) according to e and the average effective pressure Pe. The engine speed Ne is calculated based on an input signal from the crank angle sensor 9, and the average effective pressure Pe is calculated from the engine speed Ne and the throttle opening detected by the throttle position sensor 15. It has become.

The abnormal noise reduction control determination selection means 24 includes an idling determination of the idling determination means 21, a rotation variation ΔNe detected by the rotation variation detection means 22, a mode selected by the mode selection means 23, and a battery 18. This is a means for determining the start and end of the abnormal noise reduction control based on the battery voltage V and selecting the control method.
Here, a method of reducing the load on the engine (external load) by reducing the current generated by the alternator 10 and a method of reducing the compression pressure during the compression stroke by reducing the amount of exhaust gas recirculated by the EGR 6 to rotate the engine. And a method of reducing fluctuation.

The abnormal noise reduction control is started when the engine 1 is in an idling state, when lean operation by stratified combustion (compression lean mode) is performed, and when the rotational fluctuation ΔNe is equal to or greater than a predetermined value ΔN ₀ . The condition is that all of the above must be true. Then, when all the conditions for starting the abnormal noise reduction control are satisfied, the abnormal noise reduction control determination selecting unit 24 selects a control method based on the battery voltage V of the battery 18.

In other words, reducing the amount of exhaust gas recirculation in the EGR 6 increases the amount of NOx emission. Therefore, it is desirable to give priority to the method of reducing the current generated by the alternator 10. However, if the power generation current in the alternator 10 is reduced, the charge amount to the battery 18 is reduced. Therefore, when the remaining charge amount of the battery 18 is insufficient, the battery 18 may rise. Therefore, the predetermined voltage V ₀ corresponding to the case where the battery 18 has a sufficient remaining charge is compared with the current battery voltage V. When the battery voltage V is higher than the predetermined voltage V ₀ , the alternator 10 A method of reducing the generated current is employed, but when the voltage becomes equal to or lower than the predetermined voltage V _0, a method of reducing the amount of exhaust gas recirculated by the EGR 6 is employed.

The abnormal noise reduction control due to the decrease in the current generated by the alternator 10 is performed by alternator 25 control means. First, the configuration of the alternator 10 will be described. The alternator 10 includes a stator coil 10B having three-phase windings and a stator coil 1B.
0B, a three-phase AC generator including a field coil 10C located inside the
By rotating 0C in an energized state, an induced power is generated in the stator coil 10B, and the induced current (three-phase AC current) is converted into a DC current by the rectifier 10D to charge the battery 18. Field coil 1
Since the rotation of the crankshaft 5 is directly input to 0C via the V-belt 11, when the engine speed increases, the power supplied to the battery 18 also increases. Therefore, in the alternator 10, the energizing state of the field coil 10C is controlled by the voltage regulator 10A, the induced power generated in the stator coil 10B is adjusted, and the power supplied to the battery 18 is maintained at a specified value. . This voltage regulator 10A
Is controlled by duty control in which the ratio of the energizing time in one control cycle is a duty ratio.

As described above, the generated current of the alternator 10 is determined by the engine speed and the energizing time to the field coil 10C. To reduce the generated current while maintaining the engine speed at the idle speed, the generated current is supplied to the field coil 10C. May be reduced. Therefore, in the alternator control means 25, the voltage regulator 10A
To reduce the duty ratio of the duty control performed by the voltage regulator 10A to a predetermined value,
As a result, the current generated by the alternator 10 is reduced.

The alternator control means 25 outputs a control signal to the voltage regulator 10A and simultaneously starts an internal timer. Then, when the timer value T _A reaches the predetermined time T _A0 , the control for lowering the generated current is ended. This is to prevent the remaining charge of the battery 18 from decreasing due to a decrease in the generated current, and to prevent the battery 18 from rising. Therefore, the above-described predetermined voltage V ₀ is set within the predetermined time T _A0 . Is determined in consideration of a decrease in the battery voltage due to a decrease in the generated current at the time.

On the other hand, abnormal noise reduction control by reducing the amount of exhaust gas recirculation in the EGR 6 is performed by the EGR control means 26. The recirculation amount of the exhaust gas in the EGR 6 is controlled by the opening / closing control of the EGR valve 7 as described above, and the EGR control means 26 controls the EGR valve 7. The EGR control means 26 performs opening / closing control of the EGR valve 7 by duty control in which a duty ratio is a ratio of the open time in one control cycle, and reduces the duty ratio to a predetermined value to thereby reduce the exhaust gas recirculation amount of the EGR 6. Is to be reduced.

Further, EGR control unit 26 starts an internal timer at the same time changing the duty ratio of the switching control of the EGR valve 7, reducing control of the exhaust gas recirculation amount when the timer value T _B has reached the predetermined time T _B0 To end. This means that reducing the exhaust gas recirculation rate is
Since the amount of discharged Ox is increased, the reduction control of the exhaust gas recirculation amount is not performed for a long time, and after the predetermined time _{TB0 has} elapsed, the battery voltage V is checked again, and the battery voltage V is reduced to the predetermined value. This is because when the voltage is higher than the voltage V _0, the fluctuation of the engine rotation is reduced by controlling the reduction of the generated current of the alternator 10.

As described above, abnormal noise reduction control is performed by a method of reducing the current generated by the alternator 10 or a method of reducing the amount of exhaust gas recirculated by the EGR 6. Then, the abnormal noise reduction control determination selecting means 24 determines that the engine 1 is not in the idling state, that the selected mode of the engine 1 is a mode other than the lean operation by the stratified combustion, and that the rotational fluctuation ΔNe is a predetermined value ΔN _When any of the predetermined times T _{N0 has} elapsed since the time has become ₀ or less, the end of the abnormal noise reduction control is determined. Note that the rotation fluctuation amount ΔNe is equal to a predetermined value ΔN ₀
The control is continued for the predetermined time T _N0 even when the rotation speed becomes less than the predetermined value ΔN ₀ because the rotation fluctuation amount ΔNe itself also fluctuates and sometimes temporarily falls below the predetermined value ΔN _0.
The control is continued for a predetermined time T _{N0 in} order to determine whether or not the value falls below ₀ .

Based on the determination of the end of the abnormal noise reduction control, the alternator control means 25 inputs a control signal to the voltage regulator 10A so as to change the duty ratio to a normal duty ratio, ends the generation current reduction control, and terminates the EGR control means. Also at 26, the duty ratio of the opening / closing control of the EGR valve 7 is changed to a normal duty ratio, and the exhaust gas recirculation amount reduction control is ended.

Since the drive system abnormal noise reduction device according to one embodiment of the present invention is configured as described above, the drive system abnormal noise reduction control is performed, for example, as shown in the flowcharts of FIGS. Done. As shown in FIG. 3, first, the abnormal noise reduction control determination selecting means 24 selects a lean operation mode (compression lean mode) by stratified combustion as a precondition for starting or continuing the abnormal noise reduction control. (Step S100), and that the engine 1 is idling (step S1).
10) is determined.

When the above two conditions are satisfied, it is determined whether or not the abnormal noise reduction control has already been performed, that is, the abnormal noise reduction control due to the reduction in the generated current has been performed and the power generation reduction flag F or _a is set (F _a = 1) (step S120), whether the EGR decrease flag F _B is abnormal sound reduction control is performed by reducing the amount of recirculated exhaust gas is set (F _B = 1) ( Step S130)
Is determined.

When the abnormal noise reduction control has not been performed yet
(Ie, F_A, F_B= 0), the engine speed
The amount of fluctuation ΔNe is detected, and the rotation fluctuation ΔNe and a predetermined value
ΔN ₀Are compared (step S140). And times
The rotation fluctuation amount ΔNe is a predetermined value ΔN ₀If so, M
/ T etc. are likely to generate abnormal noise from the drive system
Step S2 shown in FIG. 4 to start abnormal noise reduction control
Move to 00.

When the abnormal noise reduction control start condition is satisfied, the abnormal noise reduction control determination selecting means 24 selects a control method based on the battery voltage V as shown in FIG. 4 (step S200). That is, if the battery voltage V is higher than the predetermined voltage V _0, a control method for reducing the fluctuation of the engine rotation by reducing the generated current of the alternator 10 is selected (step S210 and subsequent steps). _{If the value is} equal to or less than _0, a control method for reducing fluctuations in engine rotation by reducing the exhaust gas recirculation amount of the EGR 6 to prevent the battery from running down is selected (step S250 and subsequent steps).

When the control method based on the reduction of the generated current is selected by the abnormal noise reduction control determination selection means 24, the alternator control means 25 first sets a power generation reduction flag F _A (F _A = 1, step S210). and then start the power decrease timer T _a (step S220). Then, a control signal is input to the voltage regulator 10A, and the duty ratio (power supply time / control cycle) of the power supply control of the field coil 10C performed by the voltage regulator 10A is reduced to a predetermined value, whereby the power generation current of the alternator 10 is reduced. (Step S230).

On the other hand, when the control method according to a decrease in the exhaust gas recirculation amount is selected, the EGR control unit 26, first, set the EGR decrease flag F _B (F _B = 1, step S250), then EGR decrease to start the timer T _B (step S260). And the EGR valve 7
The duty ratio (opening time / control cycle) of the opening / closing control is reduced to a predetermined value to reduce the exhaust gas recirculation amount of the EGR 6 (step S270).

Then, when any abnormal noise reduction control is started, the abnormal noise reduction control determination selecting means 24 starts a rotation fluctuation small timer _TN (step S240), and proceeds to the next control cycle. That is, the process returns to step S100 in FIG.
Then, again, the condition of step S100 and step S1
It is determined whether the ten conditions are satisfied. If these two conditions are still satisfied, the abnormal noise reduction control is continued. First, the power generation decrease flag F _A is set (F _A =
If 1) has been performed (step S120), the process proceeds to step S300 in FIG. 5 to continue the abnormal noise reduction control due to a decrease in the generated current.

As shown in FIG. 5, in step S300, the order to prevent battery exhaustion due to reduction in the power generation current, reduction control of the duration of the generated current (power reduction timer value) measured T _A, power reduction timer The value T _A is a predetermined time T
_{If A0} or more, the process proceeds to step S500 in FIG. 7 to end the control. On the other hand, when the power generation decrease timer value T _A has not reached the predetermined time T _A0 , it is determined whether the rotation fluctuation amount ΔNe is smaller than the predetermined value ΔN ₀ (step S3).
10). When it is smaller than the predetermined value ΔN ₀ , it is determined whether the rotation fluctuation small timer value T _N has become equal to or longer than the predetermined time T _N0 , that is, the rotation fluctuation amount ΔNe becomes smaller than the predetermined value ΔN ₀ and the predetermined time T _N0 has elapsed. (Step S)
320) If the predetermined time T _N0 has elapsed, the process proceeds to step S500 in FIG. 7 to end the generation current reduction control. If the rotation fluctuation amount ΔNe has not yet become smaller than the predetermined value ΔN ₀ , the rotation fluctuation small timer _TN is reset and restarted (step S330).

Then, the rotation fluctuation amount ΔNe becomes a predetermined value ΔN ₀
However, if the predetermined time T _N0 has not elapsed, or if the rotation fluctuation amount ΔNe has not yet become smaller than the predetermined value ΔN ₀ , step S10 in FIG.
It returns to 0 and shifts to the next control cycle. Next, if the EGR decrease flag F _B is set (F _B = 1) (step S130), to continue the abnormal sound reduction control due to a reduction in exhaust gas recirculation amount proceeds to step S400 in FIG. 6.

As shown in FIG. 6, at step S400
Is the emission of NOx due to the long-term reduction control of exhaust gas recirculation.
In order to prevent the output from increasing, a reduction control of the exhaust gas recirculation
Duration (EGR decrease timer value) T_BAnd EGR
Decrease timer value T_BIs a predetermined time T _B0If this is the case,
The process proceeds to step S500 in FIG. 7 to end the control. one
, EGR decrease timer T_BIs a predetermined time T_B0Has not reached
The rotation variation ΔNe is equal to the predetermined value ΔN₀Smaller than
It is determined whether or not it is (Step S410), and the predetermined value ΔN₀Yo
Is smaller than the predetermined value ΔN₀
The predetermined time T_N0To determine if
(Step S420), and a predetermined time T_N0Where has passed
In this case, the process of FIG.
Proceed to step S500. Predetermined time T_N0Has not passed
In this case, the process returns to step S100 in FIG.
Move to.

Further, the rotation fluctuation amount ΔNe is still a predetermined value ΔN
If not smaller than ₀ , the rotation fluctuation small timer _TN is reset and restarted (step S43).
0), the process returns to step S100 in FIG. 3, and shifts to the next control cycle. If the control for reducing the generated current or the control for reducing the exhaust gas recirculation amount is continued, step S10
If any one of the conditions is not satisfied in steps S110 and S110, the process proceeds to step S500 shown in FIG. 7 without going to steps S120 and S130, and each control is ended.

When ending the abnormal noise reduction control, as shown in FIG.
As shown in FIG. _AIs set
It is determined whether or not the power generation is reduced (step S500).
F _AIf set, alternator control
In the means 25, the power generation reduction flag F_AReset (F_A=
0) (step S510), and
Duty ratio of the power supply control of the coil 10C (power supply time / control
Period) to the normal duty ratio.
A control signal is input to the
The control ends (step S520).

[0044] When the power reduction flag F _A is not set, it is determined whether the EGR decrease flag F _B is set (step S530). And EGR
If the decrease flag F _B is set, the EGR control means 26, resets the EGR decrease flag F _B (F
_B = 0) (step S540), the exhaust gas recirculation amount reduction control is terminated, and the drive duty ratio (opening time /
The control cycle is changed to the normal duty ratio, and the opening and closing control of the EGR valve 7 is performed at the normal duty ratio (step S550).

As described above, according to the drive system abnormal noise reduction device, in the in-cylinder injection type engine, when the lean operation is performed by the stratified combustion in the idling state, the abnormal drive from the drive system such as the M / T is performed. Although the fluctuation of the engine rotation which causes the sound generation is likely to be large, the rotation fluctuation ΔNe is a predetermined value Δ
When it becomes N ₀ or more, the generated current of the alternator 10 is reduced, so that the load for driving the alternator 10 by the engine 1 can be reduced,
This has the advantage that fluctuations in engine speed can be reduced.

The remaining charge of the battery 18 is small.
If the generated current of the alternator 10 cannot be reduced, the exhaust gas recirculation amount of the EGR 6 is reduced, so that the influence of the variation in the compression pressure due to the variation in the opening control of the EGR valve 7 is suppressed, and the combustion is reduced. There is an advantage that the compression pressure can be reduced by reducing the amount of intake air into the chamber 2 and thereby fluctuations in engine rotation can be reduced.

It should be noted that the present invention is not limited to the above-described embodiment, and can be variously modified and implemented without departing from the gist of the present invention. For example, in the above-described embodiment, when performing the abnormal noise reduction control by reducing the generated current of the alternator 10, the control is stopped when a predetermined time T _{A0 has} elapsed in order to prevent the battery 18 from running out. However, by setting a second predetermined voltage V ₀ ′ lower than the first predetermined voltage V ₀ ,
The control may be terminated when the battery voltage V reaches the second predetermined voltage V ₀ ′.

In the above-described embodiment, one of the noise reduction control by reducing the generated current of the alternator 10 and the noise reduction control by reducing the exhaust gas recirculation amount of the EGR 6 is selected. However, it is also possible to perform these two controls simultaneously. For example, if the rotation fluctuation ΔNe does not become smaller than the predetermined value ΔN ₀ even if the generation current of the alternator 10 is reduced for a predetermined time while performing the noise reduction control mainly by reducing the generation current of the alternator 10,
The recirculation amount of the exhaust gas of the EGR 6 is also reduced. As a result, it is expected that the external load accompanying the driving of the alternator 10 is reduced, the internal load of the engine 1 is also reduced due to the decrease in the compression pressure due to the decrease in the intake air, and the fluctuation of the engine rotation is further reduced.

Note that only one of the abnormal noise reduction control by reducing the exhaust gas recirculation amount and the abnormal noise reduction control by reducing the generated current may be executed. Further, in the above-described embodiment, the case where the drive system abnormal noise reduction device of the present invention is applied to the in-cylinder injection type engine has been described. The present invention is not limited to the type engine but can be applied to a normal engine. However, even in this case, a greater effect can be expected with an engine having a large compression pressure at the time of idling. For example, a high compression engine such as a diesel engine is similar to the in-cylinder injection engine of the above-described embodiment. Thus, a remarkable effect can be obtained.

Further, in the above-described embodiment, the idling time has been described as an example of the specific noise-generating operation area. However, the present invention is not limited to idling. That is, if there is another operating region where the fluctuation of the engine rotation is large, such as during idling,
Even in such an operating region, by applying the drive system abnormal noise reduction device, generation of abnormal noise from the drive system such as the M / T can be effectively prevented.

[0051]

As described above in detail, according to the drive system abnormal noise reducing device of the present invention, the operating region determining means determines that the operating region of the internal combustion engine is in the specific noise generating operating region. It is determined, and when the rotation fluctuation amount of the internal combustion engine detected by the rotation fluctuation amount detection means is equal to or more than a predetermined value,
Since the alternator control means reduces the generated current value of the alternator, the external load of the internal combustion engine associated with driving the alternator can be reduced,
It is possible to suppress rotation fluctuations due to an external load and reduce abnormal noise generated from the drive system.

In particular, a greater effect can be obtained in an internal combustion engine having a large intake air amount into the combustion chamber and a high compression pressure. According to the drive system abnormal noise reduction device of the present invention, the operating region determining unit determines that the operating region of the internal combustion engine is in the specific noise generating operating region, and detects the rotational fluctuation amount detecting unit. If the rotation variation of the internal combustion engine is equal to or greater than a predetermined value, the EGR control means
Since the amount of exhaust gas recirculation of the means is reduced, the increase in compression work due to the recirculation of exhaust gas by the EGR means can be reduced, and the rotational fluctuation of the internal combustion engine caused by the increase in compression work is suppressed to drive the engine. The noise generated from the system can be reduced.

In particular, a greater effect can be obtained in an internal combustion engine having a large intake air amount into the combustion chamber and a high compression pressure.

[Brief description of the drawings]

FIG. 1 is a schematic diagram showing a configuration of a direct injection engine to which a drive system abnormal noise reduction device according to an embodiment of the present invention is applied.

FIG. 2 is a functional block diagram showing a configuration of a drive system abnormal noise reduction device according to one embodiment of the present invention.

FIG. 3 is a flowchart showing a flow of abnormal noise reduction control of a drive system abnormal noise reduction device according to one embodiment of the present invention.

FIG. 4 is a flowchart showing a flow of abnormal noise reduction control of the drive system abnormal noise reduction device according to one embodiment of the present invention.

FIG. 5 is a flowchart showing a flow of abnormal noise reduction control of a drive system abnormal noise reduction device according to one embodiment of the present invention.

FIG. 6 is a flowchart showing a flow of abnormal noise reduction control of the drive system abnormal noise reduction device according to one embodiment of the present invention.

FIG. 7 is a flowchart showing the flow of abnormal noise reduction control of the drive system abnormal noise reduction device according to one embodiment of the present invention.

FIG. 8 is an explanatory diagram for explaining a problem to be solved by the present invention, in which (a) compares the fluctuation of the engine rotation of a direct injection type engine with the fluctuation of the engine rotation of a normal MPI engine; FIG. 3B is a diagram showing a change in engine rotation of the in-cylinder injection type engine when an external load is applied.

DESCRIPTION OF SYMBOLS 1 Engine (internal combustion engine) 6 EGR (EGR means) 7 EGR valve 10 Alternator 18 Battery 20 ECU 21 Idling determination means (Operating area determination means) 22 Rotation fluctuation amount detection means 23 Mode selection means 24 Abnormal noise reduction Control judgment selection means 25 Alternator control means 26 EGR control means

Continued on the front page F-term (reference) 3G084 AA00 AA04 BA20 BA34 CA03 DA11 DA39 EA07 EA11 FA03 FA05 FA10 FA34 FA38 3G092 AA01 AA06 AA09 AA17 DC09 EA02 EA17 EC08 FA05 FA14 GA04 GA17 HA06Z HE02X HE02Z HE03ZA03 CA04 DA01 DA06 DA07 DA14 DB06 DB23 EA00 EB09 FA11 FB02

Claims (2)

[Claims] 1. An operating area determining means for determining whether an operating area of an internal combustion engine is in a specific noise generating operating area, a rotational fluctuation amount detecting means for detecting a rotational fluctuation amount of the internal combustion engine, and the internal combustion engine And an alternator control means for controlling a generated current value of the alternator, wherein the alternator control means sets the operation area of the internal combustion engine to the specific noise generating operation area by the operation area determination means. When the rotation fluctuation amount of the internal combustion engine detected by the rotation fluctuation amount detecting means is equal to or more than a predetermined value, the power generation current value of the alternator is reduced. System abnormal noise reduction device. 2. An operating area determining means for determining whether an operating area of the internal combustion engine is in a specific noise generating operating area, a rotational fluctuation detecting means for detecting a rotational fluctuation of the internal combustion engine, and the internal combustion engine. EGR means for recirculating exhaust gas to the intake system, and EGR control means for controlling the amount of exhaust gas recirculated by the EGR means. The EGR control means determines that the operating range of the internal combustion engine is determined by the operating range determining means. When it is determined that the engine is in a specific noise generating operation area, and the rotation fluctuation amount of the internal combustion engine detected by the rotation fluctuation amount detection unit is equal to or more than a predetermined value,
A drive system abnormal noise reduction device, characterized in that the exhaust gas recirculation amount of the EGR means is reduced.