JP2010196602A - Idling rotation speed controller of internal combustion engine - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an idling rotation speed controller of an internal combustion engine capable of stabilizing the rotation speed of the engine during idle operation while suppressing a fuel consumption when a small amount of an external load is applied. <P>SOLUTION: When an external load G is determined to be a predetermined value α or less (G≤α), the reference ignition timing TiS is set to an ignition timing TiA by correcting a reference ignition timing TiB set when the external load G is more than the predetermined value α (G>α) by an advance correction (ΔTi). In addition, the amount of intake air is set to an amount of air GaA by correcting an amount of intake air Ga by a reduction (ΔGa). <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to an idle rotation speed control device that controls an engine rotation speed during idling of an internal combustion engine.

  Conventionally, during idling operation of an internal combustion engine, when the engine rotational speed is lower than the target rotational speed, a technique for executing advance correction of the ignition timing and increase correction of the intake air amount to increase the output torque of the engine It has been known. As a cause of the decrease in the engine rotational speed in this way, there is an increase in the external load due to the drive of the alternator using the output of the internal combustion engine or the operation of the air conditioner. For example, in the control device described in Patent Document 1, when the voltage of the battery greatly decreases, the engine rotation speed is stabilized by correcting the advance of the ignition timing.

JP-A-6-249117

  By the way, as is well known, the ignition timing of the engine is variously changed in a range on the retarded side with reference to MBT (Minimum Advance for the Best Torque), which is an ignition timing at which the maximum torque is obtained.

  Here, as described above, when the advance timing of the ignition timing is corrected and the output torque of the engine is increased when the engine speed is reduced, the ignition timing before the advance is delayed relatively far from the MBT. By setting the timing on the corner side, a sufficient correction allowance for such ignition timing correction can be secured.

  Further, the amount of increase in the output torque obtained when the ignition timing is advanced by the same crank angle tends to become larger as the ignition timing before advancement is separated from the MBT. Therefore, as described above, the ignition timing before the advance is set to the retard side that is relatively far away from the MBT, so that the ignition timing is corrected when the engine speed is reduced. It is also possible to greatly increase the output torque at that time, and it is possible to increase the output torque commensurate with the degree of decrease in engine rotation speed commensurate with the increase in external load.

  However, when the ignition timing is set at a retarded timing that is relatively far away from the MBT in this way, an output torque comparable to that obtained when the ignition timing is set near the MBT is obtained. Therefore, it is necessary to increase the intake air amount as much as possible to increase the fuel injection amount, and there is a problem that the fuel consumption increases.

  The present invention has been made in view of such circumstances, and an object of the present invention is to idle rotation of an internal combustion engine that can stabilize the engine rotation speed during idle operation while suppressing fuel consumption when the external load is small. It is to provide a speed control device.

In the following, means for achieving the above object and its effects are described.
The invention according to claim 1 is an idle rotation speed control device that performs ignition timing control and intake air amount control of the engine so as to make the engine rotation speed during idling operation of the internal combustion engine coincide with the target rotation speed. And determining means for determining whether or not the external load of the engine is equal to or less than a predetermined value. When the determination means determines that the external load is equal to or less than the predetermined value, the external load exceeds the predetermined value. And executing a load reduction process for correcting the advance of the ignition timing with respect to the ignition timing of the engine set when the engine is running, and reducing the intake air amount in accordance with the advance correction of the ignition timing. And

  When the external load of the internal combustion engine is relatively small, the fluctuation of the engine rotational speed caused by the fluctuation of the external load becomes small, and the engine rotational speed tends to be stabilized. Therefore, when the external load is relatively small, the engine rotation speed can be controlled to the target rotation speed even if the ignition timing correction allowance is made smaller than when the external load is large. Therefore, the ignition timing when the external load is relatively small can be closer to MBT than when the external load is large, and the ignition timing is set to a timing that is more advanced than the ignition timing that is set when the external load is large. It is possible to set.

  Therefore, in the above configuration, when it is determined that the external load of the engine is equal to or smaller than the predetermined value and the external load is small, the ignition timing is corrected to advance with respect to the ignition timing set when the external load is large. I have to.

  Here, if the ignition timing is corrected to advance, the output torque of the engine increases. In this configuration, the intake air amount is corrected to decrease along with such advance correction. Therefore, the increase in output torque due to the advance correction of the ignition timing is suppressed by the decrease in the fuel injection amount performed in accordance with the decrease correction of the intake air amount, thereby suppressing the fuel consumption when the external load is small. Will be able to.

  Further, in the same configuration, as described above, when it is determined that the external load is equal to or less than the predetermined value, the ignition timing is corrected to advance with respect to the ignition timing set when the external load exceeds the predetermined value. At the same time, the intake air amount is corrected to decrease along with the advance correction of the ignition timing. Therefore, the ignition timing when the external load exceeds the predetermined value and the external load is determined to be large is a retarded value compared to the case where the external load is determined to be small, and the ignition timing is corrected. A sufficient fee can be secured. Therefore, even in a situation where the external load is large and the fluctuation of the engine speed caused by the fluctuation of the external load tends to be large, the engine speed can be satisfactorily stabilized by adjusting the ignition timing. become.

As described above, according to the configuration, it is possible to stabilize the engine speed during idling while suppressing the fuel consumption when the external load is small.
As the predetermined value, for example, a value that can be determined that the external load is sufficiently small and the fluctuation of the engine speed caused by the fluctuation of the external load is less likely to occur can be employed.

  As described in claim 2, the correction amount for reducing the amount of intake air in the load reduction process includes the output torque of the engine before and after the advance correction of the ignition timing by the load reduction process. It is possible to adopt a mode in which they are set to be the same.

  According to a third aspect of the present invention, in the idling engine speed control device for an internal combustion engine according to the first or second aspect, the advance correction of the ignition timing in the load reduction process is performed by using the reference ignition timing in the ignition timing control. The gist is that it is to be corrected.

  In the ignition timing control during idling, the reference ignition timing is set based on the target rotational speed, the engine coolant temperature, etc., and the reference ignition timing is determined according to the degree of deviation between the actual engine rotational speed and the target rotational speed. An advance angle correction amount and a retard angle correction amount are calculated with respect to, and the ignition timing is corrected by each of these correction amounts.

  Therefore, as the advance correction of the ignition timing in the process at the time of load reduction, in addition to the aspect in which the advance angle correction amount is set to a larger value, the reference ignition timing that becomes the reference in the ignition timing correction as in the same configuration is used. It is also possible to adopt a mode in which it is corrected to the advance side.

  According to a fourth aspect of the present invention, in the idling engine speed control device for an internal combustion engine according to any one of the first to third aspects, an alternator load that detects a load of an alternator that generates electric power using the output of the engine. The determination means, and an air conditioner operating state detection means for detecting whether an air conditioner provided on a vehicle on which the engine is mounted and operating using the output of the engine is in an operating state. The means detects that the load detected by the alternator load detecting means is not more than a predetermined load judgment value, and that the air conditioner operating state detecting means detects that the air conditioner is not in an operating state. The gist is to determine that the external load is not more than a predetermined value when both of these conditions are satisfied.

  The increase in the external load that causes the engine speed of the internal combustion engine to decrease is due to the increase in the load of the alternator that generates power using the output of the engine, or the air conditioner that operates using the output of the engine. Occurs when is activated.

  Therefore, as the external load determination mode by the determination means, as in the same configuration, when it is detected that the load of the alternator is not more than a predetermined load determination value and the air conditioner is not in the operating state, A mode in which it is determined that the load is equal to or less than the predetermined value can be adopted.

As the load determination value in the same configuration, for example, a value that can be used to determine that the engine speed becomes unstable due to an increase in the load of the alternator can be employed.
According to a fifth aspect of the present invention, in the idle speed control device for an internal combustion engine according to the fourth aspect of the present invention, voltage detection means for detecting an actual voltage of a battery that stores electric power generated by the alternator, and the voltage detection Charge request calculation means for calculating a charge request amount for the battery so that the actual voltage detected by the means becomes a target battery voltage, and charge control means for controlling the power generation amount of the alternator according to the charge request amount And when the third condition that the first condition, the second condition, and the charge request amount are equal to or less than a predetermined request determination value is satisfied, The gist is to determine that the value is less than or equal to the value.

  In recent internal combustion engines, the target battery voltage is set according to the power demand, and when the actual battery voltage is lower than the target battery voltage, it is determined that charging is necessary, and the degree of divergence between the actual voltage and the target battery voltage is determined. Is set as a charge request amount, and so-called charge control is performed in which the load (power generation amount) of the alternator is controlled so that a power generation amount corresponding to the charge request amount is obtained.

  In an internal combustion engine in which such charge control is performed, even if it is determined by the determination means that the first condition and the second condition are satisfied, if the charge request amount is large at the time of the determination, There is a possibility that the load on the alternator increases and the first condition is not satisfied. On the other hand, if the amount of charge required is small at the time of the determination, the load on the alternator is kept low for a while after that, and it may be possible to continue to satisfy the first condition.

  Therefore, in the same configuration, as a condition for determining the state of the external load, in addition to the first condition and the second condition, the third condition that the charge request amount is equal to or less than a predetermined request determination value, that is, the load of the alternator is A determination condition that can be determined to be likely to be maintained in a low state is added. Therefore, it can be suitably determined that there is a possibility that the external load may be maintained in the state below the predetermined value not only at the time when it is determined that the external load is below the predetermined value, but also for a while after that. It becomes like this.

As the request determination value in the same configuration, for example, a value that can determine that the engine speed becomes unstable due to an increase in the load of the alternator can be adopted.
The invention according to claim 6 is the idling rotational speed control device for the internal combustion engine according to claim 4 or 5, further comprising load increase prediction means for predicting that the external load increases above the predetermined value, The gist is that when the increase in the external load is predicted by the load increase prediction means, the processing at the time of load reduction is stopped.

  According to the above configuration, when the increase in the external load is predicted by the load increase prediction unit, the execution of the load decrease process is stopped, so that both the ignition timing and the intake air amount are determined by the load decrease process. The state before the correction is performed is restored. Thereby, in anticipation of an increase in the external load, the ignition timing and the intake air amount can be brought into a state corresponding to a large external load. Therefore, it is possible to suppress the fluctuation of the engine speed immediately after the increase of the external load. In this configuration, when the increase in the external load is predicted, the above-described processing when the load is reduced is stopped, or the delay time until the external load actually increases after the increase in the external load is predicted. It is possible to adopt a mode in which the load reduction process is stopped when the time has elapsed.

  According to a seventh aspect of the present invention, in the idling engine speed control device for an internal combustion engine according to the sixth aspect, voltage detection means for detecting an actual voltage of a battery that stores electric power generated by the alternator, and the voltage detection Charge request calculation means for calculating a charge request amount for the battery so that the actual voltage detected by the means becomes a target battery voltage, and charge control means for controlling the power generation amount of the alternator according to the charge request amount And the load increase prediction means determines that the external load is greater than the predetermined request determination value when the determination means determines that the first condition is satisfied. The gist is to predict that the predetermined value will increase.

  As described above, in an internal combustion engine in which charge control is performed, even if it is determined that the first condition is satisfied by the determination unit, There is a possibility that the load on the alternator increases and the external load exceeds a predetermined value. Therefore, by configuring the load increase prediction means as in the above configuration, it is possible to predict that the external load will increase above the predetermined value as the alternator generates power.

As the request determination value in the same configuration, for example, a value that can determine that the engine speed becomes unstable due to an increase in the load of the alternator can be adopted.
Further, as a prediction mode by the load increase prediction means, as described in claim 8, an operation request of an air conditioner that is provided in a vehicle on which the engine is mounted and operates using the output of the engine is detected. It is also possible to adopt a mode in which when the air conditioner operation request detecting means detects that an air conditioner operation request has been made, it is predicted that the external load will increase above the predetermined value.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a schematic diagram showing an internal combustion engine 10 and its peripheral configuration to which a first embodiment of an internal combustion engine idle speed control device according to the present invention is embodied; The figure which shows the relationship between ignition timing and the output torque of an internal combustion engine. The time chart which shows the change aspect of the output torque according to the change of the external load in the embodiment, reference | standard ignition timing, intake air amount, and fuel injection amount. The time chart which shows the change aspect of the external load in the embodiment. The flowchart which shows the process sequence of idle rotation speed control in the embodiment. The flowchart which shows the process sequence of idle rotation speed control in the embodiment. The flowchart which shows the process sequence of idle rotation speed control in 2nd Embodiment.

(First embodiment)
Hereinafter, a first embodiment of an internal combustion engine idle speed control apparatus according to the present invention will be described with reference to FIGS.

  FIG. 1 shows an internal combustion engine 10 to which the idle speed control device according to the present embodiment is applied and its peripheral configuration. As shown in FIG. 1, a piston 11 is accommodated in a cylinder of the internal combustion engine 10 so as to be able to reciprocate. A combustion chamber 12 is defined by a top surface of the piston 11 and an inner peripheral surface of the cylinder. Has been.

  The intake passage 13 connected to the combustion chamber 12 is provided with a fuel injection valve 30 for injecting and supplying fuel into the intake passage 13. A throttle valve 15 that adjusts the intake air amount Ga is provided in a portion of the intake passage 13 upstream of the fuel injection valve 30.

  A spark plug 20 that ignites an air-fuel mixture of air supplied through the intake passage 13 and fuel injected and supplied from the fuel injection valve 30 is attached to the combustion chamber 12. The air-fuel mixture burns by the spark plug 20 and the piston 11 reciprocates, whereby the crankshaft 16 that is the output shaft of the internal combustion engine 10 rotates. Then, the exhaust gas after combustion is discharged to an exhaust passage 14 connected to the combustion chamber 12.

  An alternator 50 that generates electric power using the rotational force of the crankshaft 16 is connected to the crankshaft 16, and the electric power generated by the alternator 50 is stored in the battery 40.

  The crankshaft 16 is connected to a compressor (air conditioner compressor) 60 for an air conditioner used for air conditioning of a vehicle on which the internal combustion engine 10 is mounted. The air conditioner compressor 60 rotates using the rotational force of the crankshaft 16, and the air conditioner is operated.

  Various controls in the internal combustion engine 10 are performed by the electronic control unit 70. The electronic control unit 70 is a central processing unit (CPU) that executes arithmetic processing for engine control, a memory for storing programs and various information necessary for engine control, and for inputting and outputting signals to and from the outside. Input port and output port. The following various sensors for detecting the engine operating state are connected to this input port.

  An air flow meter 71 provided in the intake passage 13 and upstream of the throttle valve 15 detects the amount of intake air (intake air amount Ga) passing through the intake passage 13. A throttle opening sensor 72 provided in the throttle valve 15 in the intake passage 13 detects the opening of the throttle valve 15 (throttle opening TA). The rotational speed sensor 73 detects the rotational angle (crank angle CA) of the crankshaft 16 and calculates the engine rotational speed Ne based on this detection signal. The air conditioner switch 74 is a switch of the air conditioner operated by the driver, and outputs an “on signal” or an “off signal” depending on the operation state. Then, it is detected from the output of the “ON signal” that an air conditioner operation request has been made. The engine water temperature sensor 75 detects the cooling water temperature Tw of the internal combustion engine 10.

  The electronic control unit 70 grasps the operating state of the internal combustion engine 10 based on signals input from the various sensors described above and executes various controls. For example, as such various controls, fuel injection control for adjusting the amount and timing of fuel supplied from the fuel injection valve 30, ignition timing control for adjusting the ignition timing Ti of the air-fuel mixture by the spark plug 20, and adjustment of the intake air amount Ga. Therefore, intake air amount control for adjusting the opening degree TA of the throttle valve 15 and drive control for the air conditioner compressor 60 are executed.

  In addition, the electronic control unit 70 sets a target battery voltage (target voltage) VeH according to the power demand, detects the actual voltage Ve of the battery 40, and charges when the actual voltage Ve is lower than the target voltage VeH. Therefore, so-called charging control for controlling the load (power generation amount) of the alternator 50 is executed. As this charge control, a charge request amount ΔVe indicating the degree of deviation between the actual voltage Ve and the target voltage VeH is calculated, and the load (power generation amount) of the alternator 50 is obtained so that a power generation amount corresponding to the charge request amount ΔVe is obtained. Be controlled. More specifically, the alternator 50 includes a voltage regulator for controlling the power generation output, and the electronic control unit 70 performs duty control based on the duty command value D on the voltage regulator. The power generation amount is controlled by generating an output corresponding to the duty command value D. Note that the electronic control unit 70 detects voltage actual voltage Ve of the battery 40, charging request calculating means for calculating the required charging amount ΔVe to the battery 40 so that the actual voltage Ve becomes the target voltage VeH, and charging. This corresponds to the charge control means for controlling the power generation amount of the alternator 50 according to the required amount ΔVe.

  As described above, the alternator 50 and the air conditioner compressor 60 that operate using the output of the engine 10 are connected to the crankshaft 16 that is the output shaft of the internal combustion engine 10. Therefore, when the load Lt of the alternator 50 is increased or when the air conditioner is in an operating state and the air conditioner compressor 60 is operated, the external load of the internal combustion engine 10 is increased. When the external load increases in this way, especially when the internal combustion engine 10 is idling, the engine rotational speed Ne tends to fluctuate due to fluctuations in the external load, and the engine rotational speed Ne tends to become unstable.

  Therefore, the electronic control unit 70 executes idle rotation speed control that performs ignition timing control and intake air amount control of the engine 10 so that the engine rotation speed Ne during the idling operation of the internal combustion engine 10 matches the target rotation speed NeT. To do.

  In the intake air amount control in the idle rotation speed control, the intake air amount is corrected to cope with a decrease or increase in the engine rotation speed Ne caused by an increase or decrease in the external load. That is, the increase correction amount and the decrease correction amount of the target intake air amount Gap are calculated according to the increase / decrease of the external load, and the target intake air amount Gap is corrected to increase / decrease with these correction amounts. Then, the opening degree of the throttle valve 15 is adjusted so that the corrected target intake air amount Gap and the actual intake air amount Ga coincide with each other, and an increase correction and a decrease correction of the target intake air amount Gap are supported. The fuel injection amount is increased or decreased according to the actual increase or decrease of the intake air amount Ga. As a result, the engine output torque Tr is adjusted to a torque corresponding to the magnitude of the external load, and a decrease or increase in the engine rotational speed Ne caused by an increase or decrease in the external load is suppressed.

  Further, in the ignition timing control in the idle rotation speed control, the ignition timing is corrected in order to suppress the fluctuation of the engine rotation speed Ne. Specifically, the reference ignition timing TiS is set based on the target rotation speed NeT, the coolant temperature Tw of the internal combustion engine 10, and the like, and the reference is determined according to the degree of deviation between the actual engine rotation speed Ne and the target rotation speed NeT. An advance angle correction amount and a retard angle correction amount with respect to the ignition timing TiS are calculated, and the ignition timing Ti is corrected by each of these correction amounts.

  FIG. 2 shows changes in the output torque Tr of the internal combustion engine 10 when the ignition timing Ti is changed while keeping the intake air amount Ga at the same amount. The ignition timing Ti of the internal combustion engine is variously changed in the range on the retarded side with reference to MBT (Minimum Advance for the Best Torque), which is the ignition timing at which the maximum torque is obtained, through the ignition timing control. . For example, if the ignition timing TiB shown in FIG. 2 is set to the reference ignition timing TiS, and the ignition timing Ti is advanced (ΔTiB) as the engine speed Ne decreases, the internal combustion engine 10 Since the output torque Tr increases (ΔTrB), the engine speed Ne increases accordingly. Therefore, when the actual engine rotational speed Ne is lower than the target rotational speed NeT, an advance correction amount with respect to the reference ignition timing TiS is calculated according to the degree of deviation between the engine rotational speed Ne and the target rotational speed NeT. By reflecting the advance angle correction amount in the reference ignition timing TiS and advancing the ignition timing Ti, the engine rotational speed Ne approaches the target rotational speed NeT. Further, when the actual engine rotational speed Ne exceeds the target rotational speed NeT, a retardation correction amount for the reference ignition timing TiS is calculated according to the degree of deviation between the engine rotational speed Ne and the target rotational speed NeT, By reflecting the retard correction amount on the reference ignition timing TiS and retarding the ignition timing Ti, the engine rotational speed Ne approaches the target rotational speed NeT.

  Here, when control is performed such that the ignition timing Ti is advanced and the output torque Tr is increased as the engine speed Ne decreases, the reference ignition timing TiS is set to a delay that is relatively larger than the MBT. By setting the timing on the corner side, it is possible to secure a sufficient correction allowance for correcting the ignition timing.

  For example, as shown in FIG. 2, when the reference ignition timing TiS is set to the retarded timing TiB, the ignition timing Ti can be advanced to MBT, thereby correcting the internal combustion engine. The output torque Tr of 10 can be increased to the output torque TrH. Therefore, compared with the case where the reference ignition timing TiS is set to the advance timing TiA, it is possible to secure a large correction margin necessary for ignition timing correction.

  Further, the amount of increase in the output torque Tr obtained when the ignition timing Ti is advanced by the same crank angle tends to increase as the ignition timing before the advance is further away from the MBT. For example, when the reference ignition timing TiS is set to the advance timing TiA and when the reference timing TiB is set to the retard timing TiB, the advance correction (ΔTiA, ΔTiB) is made by the same crank amount, respectively. When the amount of increase (ΔTrA, ΔTrB) of the output torque Tr obtained in this way is compared, the amount of increase (ΔTrB) when set to the retarded timing TiB is larger than the other (ΔTrA <ΔTrB). . Therefore, by setting the reference ignition timing TiS to a retard side timing (TiB) that is relatively far away from the MBT, when the ignition timing Ti is corrected to advance when the engine speed Ne decreases. The output torque can be increased greatly and efficiently.

As described above, when the external load increases, the engine rotational speed Ne tends to fluctuate due to the fluctuation of the external load, and the engine rotational speed Ne tends to become unstable.
On the other hand, when the external load is relatively small, the fluctuation of the engine rotational speed Ne caused by the fluctuation of the external load becomes small, and the engine rotational speed Ne tends to be stabilized.

  Therefore, when the external load is relatively small, the engine rotational speed Ne can be controlled to the target rotational speed NeT even if the ignition timing correction allowance is made smaller than when the external load is large. Therefore, the ignition timing when the external load is relatively small can be closer to MBT than when the external load is large, and the ignition timing is set to a timing that is more advanced than the ignition timing that is set when the external load is large. It is possible to set.

  Therefore, in the present embodiment, when it is determined that the external load G is equal to or smaller than the predetermined value α (G ≦ α) and the external load G is small, the load reduction process described below is executed. . Note that the predetermined value α for determining that the external load G is small is determined that the external load G is sufficiently small and the fluctuation of the engine rotational speed Ne caused by the fluctuation of the external load G is less likely to occur. The possible values are set in advance.

  Next, with reference to FIG. 3, an outline of the load reduction process executed in the present embodiment will be described. FIG. 3 shows changes in the output torque Tr, the reference ignition timing TiS, the intake air amount Ga, and the fuel injection amount Qf according to changes in the external load G.

  FIG. 3 shows an example in which the external load G increases beyond a predetermined value α (G> α) in the period from time t2 to time t3 and in the period after time t5. In these periods, the output torque Tr is increased from the torque TrA to the torque TrB (ΔTr) so that the engine rotation speed Ne matches the target rotation speed NeT. Note that the alternate long and short dash line in the figure corresponds to the case where the reference ignition timing TiS is set to the retard side timing TiB shown in FIG. In this case, changes in the reference ignition timing TiS, the intake air amount Ga, and the fuel injection amount Qf when the external load G is small (G ≦ α) are shown. In this case, when the external load G is small (G ≦ α), the actual intake air amount Ga is adjusted to the intake air amount GaC so as to obtain the output torque TrA, and in accordance with the intake air amount GaC. The fuel injection amount QfC is set as the fuel injection amount Qf. On the other hand, when the external load G is large (G> α), the actual intake air amount Ga is adjusted to the intake air amount GaB (GaB> GaC) so that an output torque TrB larger than the output torque TrA is obtained. At the same time, the fuel injection amount QfB (QfB> QfC) is set as the fuel injection amount Qf corresponding to the intake air amount GaB.

Next, the load reduction process in this embodiment will be described.
When the external load G is large (G> α), the reference ignition timing TiS is set to the retarded timing TiB and the intake air amount Ga is adjusted to the intake air amount GaB, as in the prior art. .

  On the other hand, when the external load G is small (G ≦ α), the reference ignition timing TiS is advanced by a correction amount ΔTi. Specifically, with respect to the reference ignition timing TiB set when the above-described external load G is large (G> α), the reference ignition timing TiS is advanced to the reference ignition timing TiA on the advance side. .

  In order to cancel out the increase in the output torque Tr due to the advance correction of the reference ignition timing TiS, that is, before the advance correction (TiB) and after the advance correction (TiA) of the reference ignition timing TiS, the output torque Tr is The target intake air amount Gap is corrected to decrease so that the output torque TrA is obtained. In this reduction correction, the actual intake air amount Ga is corrected so as to become the intake air amount GaA that is reduced by the reduction correction amount ΔGa with respect to the intake air amount GaC.

  Along with such a correction for reducing the target intake air amount Gap, the fuel injection amount Qf is reduced from the fuel injection amount QfC by the reduction amount ΔQf to become the fuel injection amount QfA. This suppresses fuel consumption when the external load is small.

Next, with reference to FIG. 4, the change aspect of the external load G is demonstrated.
Each time shown in FIG. 4 corresponds to each time shown in FIG. 3, and FIG. 4 shows a period from time t2 to time t3 and after time t5, as in FIG. In this period, the external load G exceeds the predetermined value α (G> α).

  In the period from time t0 to time t1, all of the following first to third conditions are satisfied. In this case, it is determined that the external load G is equal to or less than the predetermined value α (G ≦ α) and the external load state is the “decrease state”, and the above-described load reduction process is executed.

(First condition) The load Lt of the alternator 50 is not more than the load judgment value LtJ (Lt ≦ TiJ).
(Second condition) The air conditioner is not in an operating state (non-operating state), that is, the air conditioner compressor 60 is in a non-operating state.

(Third condition) The required charging amount ΔVe (= target voltage VeH−actual voltage Ve) of the battery 40 is equal to or less than the required determination value VeJ (ΔVe ≦ VeJ).
Next, at time t1, the actual voltage Ve of the battery 40 is lower than the required charging voltage VeL (Ve <VeL), and the required charging amount ΔVe becomes larger than the required determination value VeJ (ΔVe> VeJ). Thereby, it is determined that the external load state is a “predicted state” where the external load G is predicted to increase from the predetermined value α (G> α) with the power generation of the alternator 50 thereafter. In this “predicted state”, the load Lt of the alternator 50 is low and the first condition is satisfied, and the external load G is maintained in a state of a predetermined value α or less (G ≦ α). Therefore, the load reduction process described above is executed also during this period. In this embodiment, the period from when the required charging amount ΔVe becomes larger than the required determination value VeJ (ΔVe> VeJ) to the actual start of power generation by the alternator 50 at time t1 is “predicted state” in this embodiment. Is set as the period. In this “predicted state” period, a delay time that occurs after the charge request amount ΔVe is larger than the request determination value VeJ (ΔVe> VeJ) until the power generation of the alternator 50 is actually started. A period corresponding to R1 is set in advance.

  Subsequently, when the period of the “prediction state” ends and the time when power generation by the alternator 50 is actually started (time t2), the power generation by the alternator 50 is actually started, whereby the load Lt of the alternator 50 is started. Exceeds the load determination value LtJ (Lt> LtJ), and accordingly, the external load G increases from the predetermined value α (G> α). Thereby, it is determined that the external load state is the “increasing state”. At this time, in the present embodiment, the load reduction process is stopped at the timing when the power generation by the alternator 50 is actually started, in other words, at the timing when the increase in the external load is predicted. Thus, the reference ignition timing TiS and the intake air amount Ga are returned to the reference ignition timing TiB and the intake air amount GaB when the external load G is large (G> α), respectively, and the output torque Tr of the internal combustion engine 10 is TrA. To TrB.

  Thus, when charging of the battery 40 by the alternator 50 is started at time t2, the actual voltage Ve of the battery 40 is thereby increased. When the actual voltage Ve reaches the target voltage VeH at time t3, power generation by the alternator 50 is stopped and the load Lt of the alternator 50 becomes smaller than the load determination value LtJ (Lt <LtJ). As a result, the first condition to the third condition are all satisfied, and the external load state becomes the “decrease state”. In this case, the load reduction process described above is executed again.

  Further, at time t4, when the air conditioner switch 74 is operated by the driver to switch from “off” to “on”, the air conditioner switch 74 outputs an “on signal”. Thereby, it is detected that the operation request of the air conditioner has been made, and the external load state is changed to the predetermined value α as the air conditioner compressor 60 is subsequently operated and the air conditioner is in the operating state. It becomes a “predicted state” that is predicted to increase (G> α). It should be noted that the period from when the air conditioner switch 74 is turned “on” at time t4 to when the operation of the air conditioner compressor 60 is actually started is also set as the “predicted state” period in this embodiment. The period of the “predicted state” at this time is a period corresponding to a delay time R2 that occurs after the air conditioner switch 74 is turned “on” and thereafter the operation of the air conditioner compressor 60 is actually started. It is set in advance.

  When the period of the “predicted state” ends and the operation of the air conditioner compressor 60 is actually started (time t5), the operation of the air conditioner compressor 60 is actually started, so that the external load G is predetermined. It becomes larger than the value α. Thereby, it is determined that the external load state is the “increasing state”. At this time, in this embodiment, the load reduction process is stopped at the timing when the operation of the air conditioner compressor 60 is actually started, in other words, at the timing when the increase in the external load is predicted. Thus, the reference ignition timing TiS and the intake air amount Ga are returned to the reference ignition timing TiB and the intake air amount GaB when the external load G is large (G> α), respectively, and the output torque Tr of the internal combustion engine 10 is TrA. To TrB.

  FIG. 4 shows an example in which the execution of the load reduction process is stopped at the end of the “predicted state” period. However, the external load state is directly changed from the “reduced state” to the “increased state”. Even at the time of change, execution of the process at the time of load reduction is stopped.

Next, with reference to FIGS. 5 and 6, an execution procedure of idle rotation speed control executed by the electronic control unit 70 will be described.
In this process, first, it is determined whether or not the engine is idling (step S100). If it is determined that the engine is not idling (step S100: NO), the process is temporarily terminated.

  On the other hand, when it is determined that the engine is idling (step S100: YES), whether the first condition is satisfied, that is, whether the load Lt of the alternator 50 is equal to or less than the load determination value LtJ (Lt ≦ LtJ). Determination is made (step S110). As described above, the load Lt of the alternator 50 corresponds to the power generation amount in the alternator 50 and is grasped based on the duty command value D described above. Further, as the load determination value LtJ, a value is set in advance so that it can be determined that the engine speed Ne becomes unstable due to an increase in the load of the alternator 50, that is, an increase in power generation amount. The processing in this step corresponds to an alternator load detection unit that detects the load Lt of the alternator 50.

  If it is determined that the first condition is satisfied (step S110: YES), then, the required charge amount ΔVe (= target voltage VeH−actual voltage Ve) calculated in the charge control is read (step S110). S120). Then, it is determined whether the third condition is satisfied, that is, whether the required charging amount ΔVe is equal to or less than the required determination value VeJ (ΔVe ≦ VeJ) (step S130). As the request determination value VeJ, a value that can determine whether the engine rotational speed Ne becomes unstable due to an increase in the load of the alternator 50 is set in advance.

  When it is determined that the third condition is satisfied (step S130: YES), it is subsequently detected that the second condition is satisfied, that is, the air conditioner is not in an operating state (non-operating state). It is determined whether or not (step S140). Specifically, when the air conditioner compressor 60 is not operating, it is detected that the air conditioner is not in an operating state. The processing in this step corresponds to air conditioner operating state detecting means for detecting whether or not the air conditioner is in an operating state.

  Further, when it is determined that the second condition is satisfied (step S140: YES), it is determined whether or not there is an air conditioner operation request (step S150). Specifically, this operation request is grasped based on the output of the “ON signal” by the air conditioner switch 74 described above. The processing in this step corresponds to air conditioner operation request detection means for detecting an operation request for the air conditioner.

  When it is determined that there is no request for operating the air conditioner (step S150: NO), it is determined that the external load G is equal to or less than the predetermined value α (G ≦ α) and the external load G is small. (Step S170). In this case, all of the first condition to the third condition are satisfied, and the external load state is determined to be the “reduced state”.

  On the other hand, when it is determined in step S110 that the first condition is not satisfied (step S110: NO), or when it is determined in step S140 that the second condition is not satisfied (step S140: NO), the external load G exceeds the predetermined value α (G> α), and it is determined that the external load G is large (step S180). The external load state in this case is determined to be the “increasing state”, and this processing is terminated without executing the above-described load reduction processing.

  On the other hand, when it is determined in step S130 that the third condition is not satisfied (step S130: NO), the charge request amount ΔVe is larger than the request determination value VeJ (ΔVe> VeJ). It is possible to determine that there is a power generation request even when the first power generation is not executed and the first condition is satisfied (Lt ≦ LtJ). That is, after that, it can be determined that the load Lt of the alternator 50 increases and the external load G may exceed the predetermined value α.

  When it is determined in step S150 that there is a request for operating the air conditioner (step S150: YES), the air conditioner is then operated and the external load G may exceed the predetermined value α. It can be judged.

  Therefore, when a negative determination is made in step S130 (step S130: NO) or an affirmative determination is made in step S150 (step S150: YES), it is predicted that the external load G will increase (step S150). S160). In this case, the external load G is still below the predetermined value α (G ≦ α), and the external load state is determined to be a “predicted state” in which an increase is predicted in the future. Each process in steps S110, S130, and S140 corresponds to a determination unit that determines whether or not the external load of the internal combustion engine 10 is equal to or less than a predetermined value α. In addition, each process in steps S110, S130, and S150 corresponds to a load increase prediction unit that predicts that the external load G increases from a predetermined value α.

  Thus, when it is determined that the external load state is either the “predicted state” or the “decreasing state” (steps S160 and S170), it is determined whether or not the external load G is the “decreasing state” (FIG. Step S200 shown in FIG. In this determination process, an affirmative determination is made when it is determined in step S170 that the external load state is the “decrease state”.

  When it is determined that the external load G is in the “decrease state” (step S200: YES), the reference ignition timing Ti is advanced (step S210). Specifically, as shown in FIGS. 2 and 3, the reference ignition timing TiS is advanced by the correction amount ΔTi as compared with when the external load G is large, and set to the ignition timing TiA.

  Next, a reduction correction of the target intake air amount Gap is performed (step S220), and this process ends. Specifically, as shown in FIG. 3, the target intake air amount Gap is corrected to decrease by the correction amount ΔGa with respect to the intake air amount GaC described above. In addition, each process of the said step S210 and step S220 is equivalent to the process at the time of load reduction.

  Thereafter, feedback control of the ignition timing Ti corresponding to the engine rotational speed Ne is executed with the reference ignition timing TiA whose lead angle is corrected as a reference. Further, through the fuel injection control, a fuel injection amount QfA of an amount suitable for the reduced intake air amount GaA is injected and supplied from the fuel injection valve 30.

  On the other hand, when it is determined in step S200 that the external load G is not in the “reduced state”, that is, when the external load G is in the “predicted state” (step S200: NO), it is determined that it is in the predicted state. It is determined whether or not the delay time R1 or the delay time R2 has elapsed from the point in time (step S230). Then, when it is determined that the delay time R1 or the delay time R2 has not elapsed (step S230: NO), the processing of the above steps S220 and S230, that is, the load reduction processing is executed.

  On the other hand, when it is determined that the delay time R1 or the delay time R2 has elapsed (step S230: YES), the load reduction process is stopped (step S240), and this process is terminated.

  When the load reduction process is stopped in this way, the reference ignition timing TiS is returned from the ignition timing TiA to the ignition timing TiB, and the intake air amount Ga is changed from the intake air amount GaA to the intake air amount GaB.

  If it is determined in step S180 that the external load G is large, normal control is executed to adjust the reference ignition timing TiS and the intake air amount Ga to a state corresponding to a large external load. That is, the reference ignition timing TiS is adjusted to the ignition timing TiB, and the intake air amount Ga is adjusted to the intake air amount GaB.

According to 1st Embodiment described above, there can exist the following effects.
(1) When the external load G is equal to or less than the predetermined value α (G ≦ α), the load reduction process is executed. In the load reduction process, the reference ignition timing TiS is advanced (ΔTi) with respect to the reference ignition timing TiB set when the external load G exceeds the predetermined value α. In addition to the advance correction of the reference ignition timing TiS, the intake air amount Ga is reduced (ΔGa) with respect to the intake air amount GaC when the reference ignition timing TiS is set to the retarded timing TiB. The Accordingly, the intake air amount Ga when the external load G is determined to be small is reduced as compared with the mode in which the reference ignition timing TiS is set to the retarded timing TiB regardless of the increase or decrease of the external load G. Thus, the fuel injection amount Qf can be reduced. Therefore, the fuel consumption when the external load is small can be suppressed.

  On the other hand, the reference ignition timing TiB when the external load G exceeds the predetermined value α (G> α) and the external load G is determined to be large is compared with the case where the external load G is determined to be small. The retarded value (TiB) is obtained, so that a sufficient allowance for the ignition timing Ti can be secured. Therefore, even in a situation where the external load G is large and the fluctuation of the engine rotational speed Ne caused by the fluctuation of the external load G tends to be large, the engine rotational speed Ne is stably stabilized by adjusting the ignition time Ti. To be able to. Therefore, according to the present embodiment, it is possible to stabilize the engine rotation speed during idle operation while suppressing fuel consumption when the external load is small.

  (2) As conditions for determining the state of the external load G, the first condition (step S110) that “the load Lt of the alternator 50 is equal to or less than the load determination value LtJ (Lt ≦ LtJ)” and “the air conditioner is In addition to the second condition (step S140) that is not “operating state”, the third condition that “the requested charging amount ΔVe is equal to or less than the required determination value VeJ (ΔVe ≦ VeJ)”, that is, the load of the alternator 50 is low. A determination condition for determining that there is a possibility of being maintained at step S130 is added. Therefore, not only when the external load G is determined to be equal to or less than the predetermined value α (G ≦ α) (period of “declining state”) but also for a while (period of “predicted state”). It can be suitably determined that there is a possibility that the external load G is maintained in a state of the predetermined value α or less.

  (3) The timing at which the external load G increases beyond the predetermined value α is predicted, the load reduction process is stopped at the same timing, and both the ignition timing and the intake air amount are corrected by the load reduction process. It is trying to return to the state of. As a result, the ignition timing and the intake air amount can be brought into a state corresponding to a large external load in anticipation of an increase in the external load G, so that fluctuations in the engine speed Ne immediately after the increase in the external load G can be suppressed. become able to.

  (4) Even if it is determined that the first condition is satisfied in the internal combustion engine 10 in which the charge control is performed, if the charge request amount ΔVe is large at the time of the determination, the alternator 50 There is a possibility that the load increases and the external load G exceeds the predetermined value α. Therefore, when it is determined that the first condition is satisfied, when the charge request amount ΔVe is larger than the request determination value VeJ, it is predicted that the external load G will increase beyond the predetermined value α. Accordingly, it is possible to predict that the external load G increases from the predetermined value α as the alternator 50 generates power.

  (5) Even when it is detected that an air conditioner operation request has been made, it is predicted that the external load G will increase beyond the predetermined value α. It can be predicted that the external load G increases from the predetermined value α as the machine operates.

(Second Embodiment)
Next, with reference to FIG. 7, a second embodiment that embodies an idle speed control device for an internal combustion engine according to the present invention will be described focusing on the differences from the first embodiment. Detailed description of the same configuration and processing is omitted.

This embodiment differs from the first embodiment in the following points. That is, in the first embodiment, the external load state is determined by classification into the following three types.
The “predicted state” in which the external load G is less than or equal to the predetermined value α (G ≦ α), but the external load G is predicted to increase thereafter.
External load G is less than or equal to a predetermined value α (G ≦ α) “declining state”
External load G exceeds predetermined value α (G> α) “Increased state”
On the other hand, in the present embodiment, the external load state is a state where the external load G is equal to or less than a predetermined value α (G ≦ α), and a state where the external load G exceeds the predetermined value α (G> α). It is determined by classifying into two types.

  In the first embodiment, the above-described first condition, second condition, and third condition are set as conditions for determining the state of the external load. On the other hand, in the present embodiment, only the first condition and the second condition are set.

Next, with reference to FIG. 7, an execution procedure of “idle rotation speed control” executed in the present embodiment will be described.
In this process, first, it is determined whether or not the engine is idling (step S300). If it is determined that the engine is not idling (step S300: NO), the process is temporarily terminated.

  On the other hand, when it is determined that the engine is idling (step S300: YES), whether the first condition is satisfied, that is, whether the load Lt of the alternator 50 is equal to or less than the load determination value LtJ (Lt ≦ LtJ). Determination is made (step S310). This determination process is the same as the determination process in step S110.

  When it is determined that the first condition is satisfied (step S310: YES), it is subsequently detected that the second condition is satisfied, that is, the air conditioner is not in an operating state (non-operating state). Is determined (step S320). This determination process is the same as the determination process in step S140.

  When it is determined that the second condition is satisfied (step S320: YES), it is determined that the external load G is equal to or smaller than the predetermined value α (G ≦ α) and the external load G is small (step S340). ). Each process in steps S310 and S320 corresponds to the determination unit in the present embodiment.

  When it is determined that the external load G is small in this way, the reference ignition timing TiS is corrected to advance (step S360), and the target intake air amount Gap is corrected to decrease (step S370). Then, this process ends. Each of these processes in steps S360 and S370 corresponds to a load reduction process, the process in step S360 is the same as the process in step S210, and the process in step S370 is the same as the process in step S220.

  On the other hand, when a negative determination is made in step S310 (step S310: NO), or when a negative determination is made regarding step S320 (step S320: NO), the external load G exceeds the predetermined value α ( G> α), and it is determined that the external load G is large (step S350). In this case, normal control is executed, and the reference ignition timing TiS and the intake air amount Ga are adjusted to a state corresponding to a large external load. That is, the reference ignition timing TiS is adjusted to the ignition timing TiB, and the intake air amount Ga is adjusted to the intake air amount GaB.

  In the present embodiment, since it is not determined that the external load state is the “predicted state” as in the first embodiment, at the time when it is determined that the external load G is large (step S350). The load lowering process as described above is stopped and normal control is executed.

According to the second embodiment described above, in addition to the function and effect (1) of the first embodiment, the following function and effect can be achieved.
(6) The increase in the external load G that causes the engine rotation speed of the internal combustion engine 10 to decrease is caused when the load of the alternator 50 that generates power using the output of the engine increases or when the output of the engine is used. This occurs, for example, when the air conditioner compressor 60 of the air conditioner that operates in an activated state. Therefore, when both of these conditions are satisfied, the first condition that the load Lt of the alternator 50 is equal to or less than the load determination value LtJ and the second condition that the air conditioner is detected not to be in operation are satisfied. It is determined that the external load G is equal to or less than the predetermined value α. Therefore, it can be appropriately determined whether or not the external load G is equal to or less than the predetermined value α.

(Other embodiments)
Note that the idling speed control device for an internal combustion engine according to the present invention is not limited to the configuration exemplified in each of the above-described embodiments, and is implemented as, for example, the following forms in which those embodiments are appropriately changed. You can also.

In the first embodiment, the process in step S130 or the process in step S150 may be omitted.
The order of the determination processing of the “determination means” shown in the above embodiments is an example, and the order can be appropriately changed.

  In the first embodiment, an example is shown in which it is determined that there is a request for operating the air conditioner based on the output of the “ON signal” of the air conditioner switch 74 operated by the driver. On the other hand, in the configuration further including an air conditioner control device that automatically controls the air conditioner according to the temperature in the vehicle, the cooling water temperature Tw of the internal combustion engine 10, etc., it responds to the operation request of the air conditioner. It may be determined that there is a request for operating the air conditioner based on a signal to be output from the air conditioner control device.

  In the first embodiment, the load reduction process is stopped when the delay time R1 or the delay time R2 as described above has elapsed. That is, as this cancellation process, the process at the time of load reduction is continued during the period of “predicted state”, and the external load G is actually increased to become the “increase period” by measuring the progress during the synchronization. Returning to normal control. However, the timing before the external load G actually increases after the external load state becomes the “predicted state” is set as the timing at which the processing at the time of load reduction is stopped and the control is returned to the normal control in this way. You may do it. Even in this case, the effect shown in the above (4) can be achieved. In addition, since the period of such “predicted state” is relatively short, even if the load reduction process is stopped within this period, it is possible to achieve an effect similar to the effect shown in (1) above. Further, when the increase in the external load G is predicted, that is, when the external load G is predicted to increase in step S160, the load reduction process may be stopped.

  In each of the above-described embodiments, the example in which the reference ignition timing TiS itself is corrected to the advance side (ΔTi) is shown as the advance correction of the ignition timing in the load reduction process. In addition, a mode in which the advance correction amount is set to a larger value while the reference ignition timing is kept the same may be adopted. That is, in this case, regardless of the change in the external load G, the reference ignition timing TiS is set to the same value, and the correction amount ΔT from the reference ignition timing TiS is set, and the correction amount ΔT Accordingly, the ignition timing Ti is corrected. That is, in the normal control executed when the external load G is large, the correction amount ΔT when the engine rotational speed Ne matches the target rotational speed NeT is set to “0”. Then, by determining the variation correction amount Δt corresponding to the variation of the engine rotational speed Ne, the correction amount ΔT (= Δt) from the reference ignition timing TiS is set. On the other hand, when the load reduction process is executed, the correction amount ΔT when the engine rotational speed Ne matches the target rotational speed NeT is the same value as “ΔTi” in each of the embodiments described above. It is set to a certain “α”. Then, the correction amount ΔT (= Δt + α) from the reference ignition timing TiS may be set by determining the variation correction amount Δt corresponding to the variation of the engine speed Ne.

  In the internal combustion engine 10 in each of the above embodiments, the intake air amount is adjusted through the adjustment of the opening degree of the throttle valve 15. However, the adjustment of the intake air amount is not limited to the adjustment of the throttle valve opening. For example, in an internal combustion engine having a mechanism capable of changing the valve timing and valve lift amount, the intake air amount can be adjusted by changing the valve timing and valve lift amount. The present invention can be similarly applied.

  The external loads shown in the above embodiments are merely examples, and if an external load that further affects the rotational speed Ne of the internal combustion engine 10 is added, the increase or decrease in these external loads By considering the above, the present invention can be applied. An example of such an external load is a hydraulic pump of a power steering device. In short, when it is determined that the external load that affects the rotational speed Ne of the internal combustion engine 10 is small, the above-described processing at the time of load reduction may be executed. An effect can be produced.

  DESCRIPTION OF SYMBOLS 10 ... Internal combustion engine, 11 ... Piston, 12 ... Combustion chamber, 13 ... Intake passage, 14 ... Exhaust passage, 15 ... Throttle valve, 16 ... Crankshaft, 20 ... Spark plug, 30 ... Fuel injection valve, 40 ... Battery, 50 DESCRIPTION OF SYMBOLS ... Alternator, 60 ... Air conditioner compressor, 70 ... Electronic control unit, 71 ... Air flow meter, 72 ... Throttle opening sensor, 73 ... Rotational speed sensor, 74 ... Air conditioner switch, 75 ... Engine water temperature sensor

Claims (8)

An idle rotation speed control device that performs ignition timing control and intake air amount control of the engine in order to match the engine rotation speed during idle operation of the internal combustion engine with a target rotation speed,
Determination means for determining whether or not the external load of the engine is equal to or less than a predetermined value;
When the determination means determines that the external load is less than or equal to a predetermined value, the ignition timing is corrected to advance with respect to the ignition timing of the engine set when the external load exceeds the predetermined value. In addition, an idling speed control device for an internal combustion engine is characterized in that a load reduction process is executed in which the intake air amount is corrected to decrease along with the advance correction of the ignition timing. The idle rotation speed control device for an internal combustion engine according to claim 1,
The intake air amount reduction correction amount in the load reduction process is set so that the output torque of the engine is the same before and after the ignition timing advance correction by the load reduction process. An idle rotation speed control device for an internal combustion engine. In the internal combustion engine idle rotation speed control device according to claim 1 or 2,
The idling speed control apparatus for an internal combustion engine, wherein the advance correction of the ignition timing in the load reduction process corrects a reference ignition timing in the ignition timing control. The idling rotation speed control device for an internal combustion engine according to any one of claims 1 to 3,
An alternator load detection means for detecting a load of an alternator that generates electric power using the output of the engine;
An air conditioner operating state detecting means for detecting whether or not an air conditioner which is provided in a vehicle on which the engine is mounted and operates using the output of the engine is in an operating state;
The determination means detects a first condition that the load detected by the alternator load detection means is not more than a predetermined load determination value, and that the air conditioner operating state detection means detects that the air conditioner is not in an operating state. And determining that the external load is equal to or less than a predetermined value when both of these conditions are satisfied as a second condition. The idle rotation speed control device for an internal combustion engine according to claim 4,
Voltage detection means for detecting an actual voltage of a battery that stores electric power generated by the alternator;
Charge request calculation means for calculating a required charge amount to the battery so that the actual voltage detected by the voltage detection means becomes a target battery voltage;
Charge control means for controlling the power generation amount of the alternator according to the charge request amount;
The determination means is configured such that the external load is equal to or less than a predetermined value when the first condition, the second condition, and the third condition that the charge request amount is equal to or less than a predetermined request determination value are satisfied. An idle rotation speed control device for an internal combustion engine, characterized by: In the internal combustion engine idle rotation speed control device according to claim 4 or 5,
A load increase prediction means for predicting that the external load increases from the predetermined value;
When the increase in the external load is predicted by the load increase prediction means, the load reduction process is stopped. In the internal combustion engine idle speed control apparatus according to claim 6,
Voltage detection means for detecting an actual voltage of a battery that stores electric power generated by the alternator;
Charge request calculation means for calculating a required charge amount to the battery so that the actual voltage detected by the voltage detection means becomes a target battery voltage;
Charge control means for controlling the power generation amount of the alternator according to the charge request amount;
The load increase prediction unit determines that the external load is greater than the predetermined value when the charge request amount is greater than a predetermined request determination value when the determination unit determines that the first condition is satisfied. An idling speed control device for an internal combustion engine characterized in that the engine speed is also expected to increase. The idling rotational speed control device for an internal combustion engine according to claim 6 or 7,
Air conditioner operation request detection means for detecting an operation request of an air conditioner that is provided in a vehicle on which the engine is mounted and operates using the output of the engine,
The load increase prediction means predicts that the external load will increase above the predetermined value when the air conditioner operation request detection means detects that the air conditioner operation request has been made. Engine idle speed control device.

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