JP5565378B2 - Internal combustion engine control system - Google Patents

Description

  The present invention relates to a control system for an internal combustion engine.

  In an internal combustion engine equipped with an electric supercharger, there is known a technique for assisting engine torque by operating the electric supercharger when a target torque is equal to or greater than a predetermined value (for example, see Patent Document 1).

  Here, even when the target torque is the same, the effect when the electric supercharger is operated differs depending on the operating state of the internal combustion engine. For example, even if the same amount of power is supplied to the electric supercharger, the degree of improvement in fuel efficiency may vary depending on the operating state of the internal combustion engine. Therefore, even if the electric supercharger is simply operated according to the target torque, there is a possibility that the degree of improvement in fuel efficiency is lowered.

JP-A-2005-330835 Japanese Unexamined Patent Publication No. 01-095537 JP 2004-182171 A Japanese Patent Laid-Open No. 01-121513 JP-A-01-257721 Japanese Patent Laid-Open No. 06-323155 JP 2007-198253 A

  An object of the present invention is to further improve fuel efficiency in an internal combustion engine control system capable of driving a supercharger with an electric motor.

In order to achieve the above object, a control system for an internal combustion engine according to the present invention comprises:
An excess of intake air taken into the internal combustion engine using a turbine disposed in the exhaust passage of the internal combustion engine and a compressor disposed in the intake passage of the internal combustion engine using exhaust energy discharged from the internal combustion engine A supercharger for feeding,
An electric motor for driving the compressor;
A battery for supplying power to the motor;
A detection unit for detecting the remaining capacity of the battery;
A supply unit for supplying electric power from the battery to the electric motor when a remaining capacity of the battery detected by the detection unit is equal to or greater than a threshold;
A threshold value setting unit that varies the threshold value between the steady operation and the transient operation of the internal combustion engine;
Is provided.

The threshold value is a lower limit value of the remaining battery capacity (SOC) at which the electric motor can be operated. When the remaining capacity of the battery is greater than or equal to the threshold value, power is supplied from the battery to the motor when an operation state for supplying power to the motor is entered. On the other hand, when the remaining capacity of the battery is less than the threshold value, if power is supplied to the motor, for example, power supplied to other devices may be insufficient, and thus supply of power from the battery to the motor is stopped. Here, by changing the threshold according to the operating state of the internal combustion engine, the frequency at which electric power is supplied to the electric motor changes according to the operating state of the internal combustion engine. That is, the frequency of supplying electric power to the electric motor can be changed according to the operating state of the internal combustion engine. Thereby, the frequency which assists a torque can be changed according to the driving | running state of an internal combustion engine. That is, since the opportunity to supply electric power to the electric motor increases in the driving state where the effect of improving the fuel efficiency is large, the fuel efficiency can be further improved.

  In the present invention, the threshold value setting unit can make the threshold value during transient operation of the internal combustion engine smaller than the threshold value during steady operation.

  Here, the lower the threshold value, the easier the electric power is supplied from the battery to the electric motor. That is, by making the threshold value at the time of transition smaller, power is easily supplied from the battery to the electric motor at the time of transition. As a result, the frequency of torque assist during transient operation can be increased.

  At the time of transient operation, the rotational speed of the turbine is lower because the temperature of the exhaust gas is lower than at the time of steady operation under the same conditions. Therefore, the effect of improving the fuel consumption when the same electric power is supplied to the motor is greater when the motor is operated during the transient operation than when the motor is operated during the steady operation. Therefore, the fuel efficiency can be further improved by making the frequency of torque assist during transient operation higher than the frequency of torque assist during steady operation.

  ADVANTAGE OF THE INVENTION According to this invention, a fuel consumption can be improved more in the control system of the internal combustion engine which can drive a supercharger with an electric motor.

It is a figure which shows schematic structure of the internal combustion engine which concerns on an Example, and its intake / exhaust system. It is the figure which showed the relationship between the power consumption of an electric motor, and the temperature of exhaust_gas | exhaustion. It is the figure which showed the relationship between power consumption and pump loss. It is the figure which showed the relationship between power consumption and a fuel consumption improvement effect. It is the figure which showed the relationship between the assist electric power which concerns on Example 1, SOC, and a threshold value. 3 is a flowchart illustrating a control flow of the electric motor according to the first embodiment. It is the figure which showed the relationship between the assist electric power which concerns on Example 2, SOC, and a threshold value. 6 is a flowchart illustrating a control flow of an electric motor according to a second embodiment.

  Hereinafter, specific embodiments of an internal combustion engine control system according to the present invention will be described with reference to the drawings.

<Example 1>
FIG. 1 is a diagram showing a schematic configuration of an internal combustion engine and its intake / exhaust system according to the present embodiment. An internal combustion engine 1 shown in FIG. 1 is a water-cooled four-cycle diesel engine having four cylinders 2. In the present embodiment, a diesel engine will be described as an example, but the present invention can be similarly applied to other gasoline engines.

An intake passage 3 and an exhaust passage 4 are connected to the internal combustion engine 1. A compressor 5 a of a turbocharger 5 that operates using exhaust energy as a drive source is provided in the middle of the intake passage 3. The intake passage 3 upstream of the compressor 5 a is provided with a first intake throttle valve 6 that adjusts the flow rate of intake air flowing through the intake passage 3. The first intake throttle valve 6 is opened and closed by an electric actuator. An air flow meter 7 is provided in the intake passage 3 upstream of the first intake throttle valve 6 to output a signal corresponding to the flow rate of the air flowing through the intake passage 3. The air flow meter 7 measures the intake air amount of the internal combustion engine 1.

  An intercooler 8 that performs heat exchange between the intake air and the outside air is provided in the intake passage 3 downstream of the compressor 5a. The intake passage 3 downstream of the intercooler 8 is provided with a second intake throttle valve 9 that adjusts the flow rate of intake air flowing through the intake passage 3. The second intake throttle valve 9 is opened and closed by an electric actuator.

  On the other hand, a turbine 5 b of the turbocharger 5 is provided in the middle of the exhaust passage 4. Further, a particulate filter (hereinafter simply referred to as a filter) 10 is provided in the exhaust passage 4 downstream of the turbine 5b. The filter 10 may carry a catalyst, for example.

  Here, the turbocharger 5 is a variable nozzle turbocharger with an electric motor. The turbocharger 5 includes a turbine 5b disposed in the exhaust passage 4, a compressor 5a disposed in the intake passage 3, an electric motor 51 that is attached to a rotary shaft between the turbine 5b and the compressor 5a and drives the compressor 5a, And a variable nozzle 52 that opens and closes so as to change the flow rate of the exhaust gas blown to the turbine 5b. The turbine 5b and the compressor 5a are integrally connected by a rotating shaft, and the compressor 5a uses the energy of the exhaust gas discharged from the internal combustion engine 1 and input to the turbine 5b to supercharge the intake air taken into the internal combustion engine. . Further, when the electric motor 51 is driven, the rotating shaft can be forcibly rotated, and thus the compressor 5a can be forcibly driven. For example, the deceleration energy of the vehicle on which the internal combustion engine 1 is mounted may be regenerated by an alternator, and the electric motor 51 of the turbocharger 5 may be operated with the regenerated electric power. In this embodiment, the turbocharger 5 corresponds to the supercharger in the present invention.

  The internal combustion engine 1 is provided with a low pressure EGR device 30 that recirculates a part of the exhaust gas flowing through the exhaust passage 4 to the intake passage 3 at a low pressure. The low pressure EGR device 30 includes a low pressure EGR passage 31, a low pressure EGR valve 32, and an EGR cooler 33.

  The low pressure EGR passage 31 connects the exhaust passage 4 downstream of the filter 10 and the intake passage 3 upstream of the compressor 5a and downstream of the first intake throttle valve 6. Through this low pressure EGR passage 31, the exhaust gas is recirculated at a low pressure. In this embodiment, the exhaust gas recirculated through the low pressure EGR passage 31 is referred to as low pressure EGR gas. The exhaust passage 4 side of the low pressure EGR passage 31 may be connected downstream of the turbine 5b. Further, the intake passage 3 side of the low-pressure EGR passage 31 may be connected upstream of the compressor 5a.

  Further, the low pressure EGR valve 32 adjusts the amount of the low pressure EGR gas flowing through the low pressure EGR passage 31 by adjusting the passage sectional area of the low pressure EGR passage 31. The EGR cooler 33 exchanges heat between the low-pressure EGR gas passing through the EGR cooler 33 and the cooling water of the internal combustion engine 1 to reduce the temperature of the low-pressure EGR gas.

  The internal combustion engine 1 is also provided with a high-pressure EGR device 40 that recirculates part of the exhaust gas flowing through the exhaust passage 4 to the intake passage 3 at a high pressure. The high pressure EGR device 40 includes a high pressure EGR passage 41 and a high pressure EGR valve 42.

The high pressure EGR passage 41 connects the exhaust passage 4 upstream of the turbine 5 b and the intake passage 3 downstream of the second intake throttle valve 9. Exhaust gas is recirculated at high pressure through the high pressure EGR passage 41. In this embodiment, the exhaust gas recirculated through the high pressure EGR passage 41 is referred to as high pressure EGR gas. The exhaust passage 4 side of the high pressure EGR passage 41 only needs to be connected upstream of the turbine 5b. Further, the intake passage 3 side of the high pressure EGR passage 41 may be connected downstream of the compressor 5a.

  Further, the high pressure EGR valve 42 adjusts the amount of high pressure EGR gas flowing through the high pressure EGR passage 41 by adjusting the passage sectional area of the high pressure EGR passage 41.

  The internal combustion engine 1 configured as described above is provided with an ECU 20 that is an electronic control unit for controlling the internal combustion engine 1. The ECU 20 controls the internal combustion engine 1 in accordance with the operating conditions of the internal combustion engine 1 and the driver's request.

  In addition to the above sensor, the ECU 20 outputs an electric signal corresponding to the amount of depression of the accelerator pedal 14 by the driver, and an accelerator opening sensor 15 that can detect the engine load, and a crank position that detects the engine speed. Sensors 16 are connected via electric wiring, and output signals from these various sensors are input to the ECU 20.

  On the other hand, the first intake throttle valve 6, the second intake throttle valve 9, the low pressure EGR valve 32, the high pressure EGR valve 42, the electric motor 51, and the variable nozzle 52 are connected to the ECU 20 through electric wiring. These devices are controlled.

  Further, the battery 11 is connected to the ECU 20, and the remaining capacity (SOC) of the battery 11 is detected by the ECU 20. The power of the battery 11 is supplied to the first intake throttle valve 6, the second intake throttle valve 9, the low pressure EGR valve 32, the high pressure EGR valve 42, and the electric motor 51. In this embodiment, the ECU 20 that detects the SOC corresponds to the detection unit in the present invention.

  The ECU 20 supplies the EGR gas from the low pressure EGR device 30, the high pressure EGR device 40, or both devices according to the operating state of the internal combustion engine 1 (for example, the engine speed and the engine load). Decide whether to supply.

  When both the engine speed and the engine load are low (low rotation and low load region), the EGR gas is supplied using only the high pressure EGR device 40. This operation region is referred to as an HPL region. For example, even when the cooling water temperature is low, the EGR gas is supplied using only the high-pressure EGR device 40. Hereinafter, a control mode for supplying EGR gas using only the high-pressure EGR device 40 is referred to as an HPL mode. The opening degree of the high pressure EGR valve 42 at this time is determined according to the operating state of the internal combustion engine 1 (for example, the engine speed and the engine load).

  Next, when at least one of the engine speed and the engine load is high (high rotation region, high load region), EGR gas is supplied using only the low pressure EGR device 30. This operation region is referred to as an LPL region. Hereinafter, a control mode for supplying EGR gas using only the low-pressure EGR device 30 is referred to as an LPL mode. The opening degree of the low pressure EGR valve 32 at this time is determined according to the operating state of the internal combustion engine 1 (for example, the engine speed and the engine load).

  An MPL area can be set between the HPL area and the LPL area. The MPL region is an operation region when the engine load is medium (medium load region). And it is an operation area | region where EGR gas is supplied using both the low voltage | pressure EGR apparatus 30 and the high voltage | pressure EGR apparatus 40. FIG. Hereinafter, a control mode in which EGR gas is supplied using both the low pressure EGR device 30 and the high pressure EGR device 40 is referred to as an MPL mode. The opening degrees of the low pressure EGR valve 32 and the high pressure EGR valve 42 at this time are determined according to the operating state of the internal combustion engine 1 (for example, the engine speed and the engine load).

The ECU 20 supplies power to the electric motor 51 when the remaining capacity (SOC) of the battery 11 is equal to or greater than the threshold value, and stops supplying electric power to the electric motor 51 when the remaining capacity is less than the threshold value. Further, the threshold value is made different between the steady operation and the transient operation of the internal combustion engine 1. Note that steady operation refers to operation in a state where the engine speed and engine load are within a substantially constant range, and transient operation refers to at least one of engine speed or engine load being substantially constant. It means driving in a state where it is moving beyond the range. The transient operation may be accelerated operation.

  Here, FIG. 2 is a diagram showing the relationship between the power consumption of the electric motor 51 and the exhaust temperature. FIG. 3 is a graph showing the relationship between power consumption and pump loss. 2 and 3, the solid line shows the case of transient operation, and the alternate long and short dash line shows the case of steady operation. The pump loss in FIG. 3 may be the difference (kPa) between the exhaust pressure upstream of the turbine 5b and the intake air pressure downstream of the compressor 5a.

  As shown in FIG. 2, when the power consumption is the same during steady operation and transient operation, the temperature of the exhaust gas is lower during transient operation than during steady operation. For this reason, a response delay occurs in the supercharging pressure during transient operation.

  Here, when the increase in the boost pressure occurs, the variable nozzle 52 is closed, and the pump loss increases. In other words, during transient operation, the pump loss increases because the increase in the boost pressure is greater than during steady operation. On the other hand, by increasing the power consumption, it is possible to increase the rate of increase of the supercharging pressure, thereby reducing pump loss. That is, in FIG. 3, as the power consumption increases, the difference in pump loss between transient operation and steady operation decreases. Therefore, the pump loss can be reduced by increasing the power supplied to the electric motor 51 during the transient operation.

  That is, at the time of steady operation of the internal combustion engine 1, the temperature of the exhaust gas is sufficiently high so that the rotational speed of the turbine 5b is high. On the other hand, during the transient operation of the internal combustion engine 1, the temperature of the exhaust gas is lower and the rotational speed of the turbine 5b is lower than during steady operation under the same conditions. Therefore, the effect of increasing the supercharging pressure by the electric motor 51 is higher during transient operation than during steady operation.

  Therefore, in the present embodiment, the electric motor 51 is positively activated during the transition. Thereby, even if the power consumption in the predetermined period is the same, the fuel consumption can be further improved.

  FIG. 4 is a diagram showing the relationship between the power consumption and the fuel efficiency improvement effect. The solid line shows the case of transient operation, and the alternate long and short dash line shows the case of steady operation. The fuel efficiency improvement effect indicates the ratio of the fuel efficiency improvement after the operation of the motor 51 to the fuel efficiency before the operation of the motor 51.

  Thus, when the power consumption is the same, the effect of improving fuel efficiency is greater during transient operation than during steady operation. Further, as the power consumption increases, the difference between the transient operation and the steady operation increases. Therefore, it is possible to effectively use limited power by supplying power preferentially during transient operation, which has a large effect of improving fuel efficiency.

  In this embodiment, when the SOC is equal to or higher than the threshold value and the control mode is the LPL mode, the ECU 20 supplies electric power to the electric motor 51 to operate the electric motor 51. In the LPL mode, since the internal combustion engine 1 is in a high rotation and high load state, the supercharging effect is high. That is, since the supercharging pressure can be quickly increased by operating the electric motor 51 in the LPL mode, drivability can be improved. In this embodiment, the ECU 20 that supplies electric power to the electric motor 51 corresponds to the supply unit in the present invention.

Here, the high-pressure EGR device 40 supplies high-pressure EGR gas using a differential pressure between the pressure P4 in the exhaust passage 4 upstream of the turbine 5b and the pressure Pb downstream of the compressor 5a. Yes. At this time, when the electric motor 51 is operated, the pressure Pb on the downstream side of the compressor 5a increases, and thus the differential pressure (P4-Pb) decreases. Therefore, if the electric motor 51 is operated in the HPL mode, the EGR gas may be insufficient and the amount of NOx generated may increase. For this reason, for example, it is conceivable to increase the supply amount of the high-pressure EGR gas by closing the variable nozzle 52, but this increases the pump loss, so that the effect of operating the electric motor 51 is reduced.

  On the other hand, the low-pressure EGR device 30 supplies the low-pressure EGR gas using a differential pressure between the pressure in the exhaust passage 4 downstream of the turbine 5b and the pressure upstream of the compressor 5a. This differential pressure hardly changes even when the electric motor 51 is operated. Therefore, even if the electric motor 51 is operated, the low-pressure EGR gas can be supplied with almost no influence. Then, when the electric motor 51 is operated, the pump loss can be reduced by opening the variable nozzle 52 as much as the pressure Pb on the downstream side of the compressor 5a is increased. For this reason, the effect of operating the electric motor 51 is great. Therefore, the improvement degree of the fuel consumption per unit power consumption can be further increased by operating the electric motor 51 in the LPL mode and stopping the electric motor 51 in the HPL mode. In this way, limited power can be used efficiently. Note that the opening degree of the variable nozzle 52 may be increased as the driving force (which may be power consumption) of the electric motor 51 is increased.

  A threshold value is set as a lower limit value of the remaining battery capacity (SOC) when power is supplied from the battery 11 to the electric motor 51, and electric power is supplied from the battery 11 to the electric motor 51 only when the SOC is equal to or greater than the threshold value. Furthermore, by changing the threshold value between the steady operation and the transient operation, electric power is more easily supplied to the electric motor 51 during the transient operation.

  Here, FIG. 5 is a diagram illustrating a relationship among the assist power, the SOC, and the threshold value according to the present embodiment. The assist power is power supplied to the electric motor 51. The assist power is set based on the SOC-power line and the SOC. The constant threshold value Wmin1 is an SOC threshold value set during steady operation, and is, for example, 70%. The transient threshold value Wmin2 is an SOC threshold value set during transient operation, and is, for example, 60%. Thus, the transient threshold value Wmin2 is made smaller than the steady-state threshold value Wmin1. The constant threshold value Wmin1 and the transient threshold value Wmin2 are set so as to secure an SOC capable of supplying power from the battery 11 to other devices.

  During steady operation of the internal combustion engine 1, electric power is supplied to the electric motor 51 when the SOC is equal to or higher than the normal threshold Wmin1, and supply of electric power to the electric motor 51 is stopped when the SOC is lower than the normal threshold Wmin1. On the other hand, during transient operation of the internal combustion engine 1, electric power is supplied to the electric motor 51 when the SOC is greater than or equal to the transient threshold value Wmin2, and supply of electric power to the electric motor 51 is stopped when the SOC is less than the transient threshold value Wmin2.

  Then, when the SOC is greater than or equal to the transient threshold value Wmin2 and less than the steady-state threshold value Wmin1, the motor 51 operates during transient operation, but the motor 51 does not operate during steady operation. As described above, during transient operation, the electric motor 51 operates even when the SOC is smaller. Therefore, the frequency of assist performed during transient operation can be made higher than during steady operation.

  FIG. 6 is a flowchart showing a control flow of the electric motor 51 according to the present embodiment. This routine is repeatedly executed by the ECU 20 every predetermined time.

In step S101, it is determined whether or not the current control mode is the LPL mode. It may be determined whether the internal combustion engine 1 is operating in the LPL region. In this step, it is determined whether or not the low pressure EGR device 30 is in a state of supplying low pressure EGR gas. If an affirmative determination is made in step S101, the process proceeds to step S102, and if a negative determination is made, this routine is terminated.

  In step S102, it is determined whether there is an acceleration request. In this step, it is determined whether or not the driver of the vehicle on which the internal combustion engine 1 is mounted requests acceleration. Further, in this step, it may be determined whether or not the operating state of the internal combustion engine 1 is in a transient state. For example, it is determined that there is an acceleration request when the amount of change in the detected value of the accelerator opening sensor 15 is greater than or equal to a threshold value. If an affirmative determination is made in step S102, the process proceeds to step S103, and if a negative determination is made, the process proceeds to step S104.

  In step S103, the transient threshold value Wmin2 is set to the SOC threshold value Wmin that permits assist.

  In step S104, the steady-state threshold value Wmin1 is set to the SOC threshold value Wmin that permits assist. In this embodiment, the ECU 20 that processes step S102 to step S104 corresponds to the threshold setting unit in the present invention.

  In step S105, it is determined whether the remaining battery capacity (SOC) is equal to or greater than a threshold value Wmin. In this step, it is determined whether or not the SOC sufficient to operate the electric motor 51 is secured. If an affirmative determination is made in step S105, the process proceeds to step S106, and if a negative determination is made, the process proceeds to step S107.

  In step S106, electric power is supplied to the electric motor 51 to operate the electric motor 51. On the other hand, in step S107, the supply of electric power to the electric motor 51 is stopped, and the electric motor 51 is stopped.

  Thus, the frequency of assist during transient operation can be increased by making the threshold value Wmin of the SOC that permits assist smaller during transient operation than during steady operation. Thereby, a fuel consumption can be improved more.

<Example 2>
In the present embodiment, the electric power supplied to the electric motor 51 is increased during transient operation than during steady operation. Since other devices are the same as those of the first embodiment, the description thereof is omitted.

  Here, FIG. 7 is a diagram illustrating a relationship among the assist power, the SOC, and the threshold value according to the present embodiment. The assist power is power supplied to the electric motor 51. The assist power is set based on the SOC-power line and the SOC. The steady-state SOC-power line C1 is an SOC-power line set during steady operation. The transient SOC-power line C2 is an SOC-power line that is set during transient operation. Thus, the transient SOC-power line C2 is positioned on the side where the assist power is larger than the steady-state SOC-power line C1. That is, when the SOC is the same, the assist power is greater during transient operation than during steady operation. If it does so, the amount of assistance performed at the time of transient operation will become large, and a boost pressure can be raised rapidly.

  The SOC threshold Wmin is, for example, 60%, and is common during steady operation and transient operation. This threshold value Wmin is preset as, for example, a lower limit value of the SOC at which the electric motor 51 can be operated. Electric power is supplied to the electric motor 51 when the SOC is equal to or higher than the threshold value Wmin, and supply of electric power to the electric motor 51 is stopped when the SOC is lower than the threshold value Wmin.

  FIG. 8 is a flowchart showing a control flow of the electric motor 51 according to the present embodiment. This routine is repeatedly executed by the ECU 20 every predetermined time. In addition, about the step where the same process as the float shown in FIG. 6 is made, the same code | symbol is attached | subjected and description is abbreviate | omitted.

  When an affirmative determination is made in step S102, the process proceeds to step S201, and the transient SOC-power line C2 shown in FIG. 7 is set as the SOC-power line. On the other hand, if a negative determination is made in step S102, the process proceeds to step S202, and the normal-time SOC-power line C1 shown in FIG. 7 is set as the SOC-power line.

  If an affirmative determination is made in step S105, the process proceeds to step S203 to calculate assist power. The assist power is calculated using the relationship shown in FIG. 7 from the SOC and the SOC-power line set in step S201 or step S202. This calculation may be performed using a map, or may be performed according to a stored calculation formula.

  In this way, by increasing the assist power during transient operation rather than during steady operation, power can be preferentially supplied during transient operation, which is more effective. Thereby, a fuel consumption can be improved more. In addition, Example 1 and Example 2 can also be combined. That is, the SOC threshold value and the amount of power to be supplied may be different during steady operation and transient operation.

DESCRIPTION OF SYMBOLS 1 Internal combustion engine 2 Cylinder 3 Intake passage 4 Exhaust passage 5 Turbocharger 5a Compressor 5b Turbine 6 First intake throttle valve 7 Air flow meter 8 Intercooler 9 Second intake throttle valve 10 Particulate filter 11 Battery 14 Accelerator pedal 15 Accelerator opening sensor 16 Crank position sensor 20 ECU
30 Low pressure EGR device 31 Low pressure EGR passage 32 Low pressure EGR valve 33 EGR cooler 40 High pressure EGR device 41 High pressure EGR passage 42 High pressure EGR valve 51 Electric motor 52 Variable nozzle

Claims (2)

An excess of intake air taken into the internal combustion engine using a turbine disposed in the exhaust passage of the internal combustion engine and a compressor disposed in the intake passage of the internal combustion engine using exhaust energy discharged from the internal combustion engine A supercharger for feeding,
An electric motor for driving the compressor;
A battery for supplying power to the motor;
A detection unit for detecting the remaining capacity of the battery;
A supply unit for supplying electric power from the battery to the electric motor when a remaining capacity of the battery detected by the detection unit is equal to or greater than a threshold;
A threshold value setting unit that varies the threshold value between the steady operation and the transient operation of the internal combustion engine;
An internal combustion engine control system comprising:   The control system for an internal combustion engine according to claim 1, wherein the threshold value setting unit makes the threshold value during transient operation of the internal combustion engine smaller than the threshold value during steady operation.

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