Internal combustion engine control method and internal combustion engine control device

Abstract

If the automatic stop condition is met, fuel injection is stopped and the internal combustion engine (1) is automatically stopped. If a restart request is present during the process of the internal combustion engine rotation speed decreasing due to the automatic stop, if the internal combustion engine rotation speed is greater than or equal to a recoverable combustion rotation speed threshold (R1) that can be restarted only by fuel injection, the internal combustion engine (1) is started by resuming fuel injection. If the internal combustion engine rotation speed is less than the recoverable combustion rotation speed threshold (R1), the internal combustion engine (1) is started using the AC generator (6). For the internal combustion engine (1), if the internal combustion engine rotation speed is less than the recoverable combustion rotation speed threshold (R1) during the process of the internal combustion engine rotation speed decreasing due to the automatic stop, the amount of air introduced into the cylinder is reduced compared to before the internal combustion engine rotation speed is less than the recoverable combustion rotation speed threshold (R1).

Description

Technical Field

[0001] The present invention relates to a control method and a control device for an internal combustion engine. Background Art

[0002] Conventionally, there is known an internal combustion engine idle stop control that automatically stops the engine if a predetermined automatic stop condition is satisfied during idling, and automatically restarts the engine if a predetermined automatic restart condition is satisfied during the automatic stop.

[0003] For example, in Patent Document 1, during the rotational deceleration period from when the internal combustion engine is automatically stopped to when the rotational speed of the internal combustion engine is reduced to zero, if it is determined that the rotational speed of the internal combustion engine is in a prescribed rotational speed region including the resonance frequency band (resonance region) of the internal combustion engine, an electric generator is used to impart a torque on the reverse rotation side, i.e., a reverse torque, to the crankshaft of the internal combustion engine to increase the rate of decrease of the rotational speed of the internal combustion engine.

[0004] In Patent Document 1, when the internal combustion engine rotation speed is in a predetermined rotation speed range, reverse torque is applied to the internal combustion engine by power running or regenerative power generation of the motor generator, thereby increasing the rate of decrease of the internal combustion engine rotation speed and shortening the time it takes for the internal combustion engine rotation speed to pass through the resonant frequency band.

[0005] In Patent Document 1, when a reverse torque is applied to the internal combustion engine, it is determined based on various parameters whether the motor generator is to be driven for power running or to be regenerative.

[0006] However, if the internal combustion engine's rotational speed is low when passing through the resonant frequency band, the motor generator can hardly generate electricity. Therefore, in Patent Document 1, sufficient reverse torque cannot be applied to the internal combustion engine within the specified rotational speed range including the resonant frequency band, and there is a possibility that the internal combustion engine's rotational speed cannot be quickly reduced.

[0007] Therefore, in Patent Document 1, there is a possibility that it is not possible to suppress vibration when the engine rotation speed passes through the resonance frequency band during the automatic stop of the internal combustion engine.

[0008] Patent Document 1: Japanese Patent Application Laid-Open No. 2017-203401 Summary of the Invention

[0009] In the internal combustion engine of the present invention, when a request to restart the internal combustion engine is received during a period in which the engine rotational speed is reduced due to an automatic stop of the internal combustion engine, if the engine rotational speed is greater than or equal to a predetermined rotational speed threshold at which restart is possible using fuel injection alone, the internal combustion engine is started by resuming fuel injection. If the engine rotational speed of the internal combustion engine falls below the predetermined rotational speed threshold, the engine is started by cranking the internal combustion engine using the electric motor. Furthermore, if the engine rotational speed falls below the predetermined rotational speed threshold during a period in which the internal combustion engine rotational speed is reduced due to an automatic stop, the amount of air introduced into the cylinder is reduced compared to before the engine rotational speed falls below the predetermined rotational speed threshold.

[0010] When the engine rotation speed is equal to or greater than a predetermined rotation speed threshold, the amount of air in the cylinder can be ensured to cope with the start of the internal combustion engine (combustion start) by the recovery fuel injection.

[0011] Furthermore, when the engine speed falls below a predetermined speed threshold, the amount of air introduced into the cylinder (intake air) can be reduced, thereby reducing the compression reaction force and suppressing engine rotational fluctuations. By reducing the amount of air introduced into the cylinder and thus reducing the compression reaction force, vibrations in the engine can be suppressed when the engine speed passes through a predetermined resonant frequency band. BRIEF DESCRIPTION OF THE DRAWINGS

[0012] Figure 1 This is an explanatory diagram schematically showing the outline of the system configuration of an internal combustion engine to which the present invention is applied.

[0013] Figure 2 This is a timing chart showing the control state of the internal combustion engine after the automatic stop condition is satisfied.

[0014] Figure 3 This is a flowchart showing a control flow of the internal combustion engine according to the present invention. DETAILED DESCRIPTION

[0015] Hereinafter, one embodiment of the present invention will be described in detail based on the accompanying drawings. Figure 1 This is an explanatory diagram schematically showing the outline of the system configuration of an internal combustion engine 1 to which the present invention is applied.

[0016] The internal combustion engine 1 is, for example, a multi-cylinder spark-ignition gasoline internal combustion engine mounted on a vehicle such as an automobile. The internal combustion engine 1 transmits the rotation of a crankshaft 2 as driving force to the drive wheels of the vehicle. Alternatively, the internal combustion engine 1 may be a diesel internal combustion engine.

[0017] Intake air is distributed to each cylinder of the internal combustion engine 1 via a header pipe 4, which forms part of the intake passage 3. An electric throttle valve 5 is arranged upstream of the header pipe 4 to adjust the amount of intake air for the internal combustion engine 1. The throttle valve 5 functions as an air quantity adjustment unit capable of adjusting the amount of air supplied to the cylinders and is provided in the intake passage 3, upstream of the header pipe 4.

[0018] The internal combustion engine 1 includes fuel injection valves (not shown) and spark plugs (not shown). The fuel injection amount and timing of the fuel injection valves, the ignition timing of the spark plugs, and the pressure of the fuel supplied to the fuel injection valves are optimized by a control unit 21 described later.

[0019] The internal combustion engine 1 drives an alternator 6 that generates electricity for charging an on-vehicle battery, a compressor 7 of an air conditioner (air conditioner), and the like.

[0020] Here, the alternator 6 is a so-called motor generator that performs a power running operation to drive the crankshaft 2 of the internal combustion engine 1. That is, the alternator 6 corresponds to an electric motor that can rotate the crankshaft 2 to start the internal combustion engine 1 (cranking).

[0021] When there is a drive request for auxiliary machines such as the alternator 6 and the air conditioner and the auxiliary machines are driven, an auxiliary machine load acts on the internal combustion engine 1 , increasing the load on the internal combustion engine 1 .

[0022] Auxiliary machines driven by the internal combustion engine 1, such as the alternator 6 and the air conditioner, use the rotation of the crankshaft 2 transmitted via a belt 8 and a crank pulley 9 as their power source. The crank pulley 9 is integrally mounted on the end of the crankshaft 2. The belt 8 is wound around the crank pulley 9 and a pulley 10 on the auxiliary machine side.

[0023] An electromagnetic clutch 11 for air conditioning is provided between the internal combustion engine 1 and the air conditioner compressor 7. Specifically, the electromagnetic clutch 11 is provided between the auxiliary machine pulley 10 to which the rotation of the crankshaft 2 is transmitted and the air conditioner compressor 7.

[0024] The internal combustion engine 1 disengages the electromagnetic clutch 11 for the air conditioner, thereby disengaging the air conditioner compressor 7. When the air conditioner is not in use, the electromagnetic clutch 11 for the air conditioner is disengaged based on a command from the control unit 21. Specifically, when the air conditioner is not in use, the internal combustion engine 1 disengages the electromagnetic clutch 11 for the air conditioner, thereby reducing the load on the air conditioner compressor 7.

[0025] In addition, regarding the structure of various auxiliary machines driven by the internal combustion engine 1, such as air conditioners, which can reduce the load on the internal combustion engine 1 if they are disconnected from the internal combustion engine 1 when they stop, an electromagnetic clutch can be set between them and the internal combustion engine 1 to disconnect the electromagnetic clutch when they stop.

[0026] The control unit 21 receives detection signals from various sensor types, such as a crank angle sensor 22 for detecting the crank angle of the crankshaft 2, an accelerator opening sensor 23 for detecting the amount of depression of an accelerator pedal (not shown), a vehicle speed sensor 24 for detecting the vehicle speed, a brake sensor 25 for detecting the amount of depression of a brake pedal (not shown), a catalyst temperature sensor 26 for detecting the catalyst temperature of an exhaust purification catalyst (not shown) provided in an exhaust passage (not shown) of the internal combustion engine 1, and a pressure sensor 27 for detecting the pressure (air pressure) in the manifold 4.

[0027] The control unit 21 calculates the requested load (engine load) of the internal combustion engine 1 using the detection value of the accelerator opening sensor 23 .

[0028] The control unit 21 can also detect the SOC (State of Charge), which is the ratio of the remaining charge to the charge capacity of the vehicle-mounted battery (not shown).

[0029] The crank angle sensor 22 can detect the engine rotation speed (engine speed) of the internal combustion engine 1 .

[0030] When the vehicle is traveling or stopped, if a predetermined automatic stop condition is met, the fuel supply is stopped, causing the internal combustion engine 1 to automatically stop. Furthermore, if a predetermined automatic restart condition is met during the automatic stop, the internal combustion engine 1 is restarted. Specifically, the control unit 21 automatically stops the internal combustion engine 1 if the predetermined automatic stop condition is met, and automatically restarts the internal combustion engine 1 if the predetermined automatic restart condition is met.

[0031] Automatic stop conditions of the internal combustion engine 1 include, for example, the accelerator pedal is not depressed, the battery SOC of the vehicle battery is greater than a predetermined battery threshold SOCth, and the catalyst temperature of the exhaust gas purification catalyst is higher than a predetermined first catalyst temperature threshold T1.

[0032] If all of the above-mentioned automatic stop conditions are met, the internal combustion engine 1 is automatically stopped. In other words, if all of the above-mentioned automatic stop conditions are met while the internal combustion engine 1 is operating, the control unit 21 automatically stops the internal combustion engine 1. Specifically, the control unit 21 functions as a first control unit that automatically stops the internal combustion engine 1 by stopping fuel injection when the predetermined automatic stop conditions are met.

[0033] Automatic restart conditions for the internal combustion engine 1 include, for example, the accelerator pedal is depressed, the battery SOC of the vehicle battery is less than or equal to a predetermined battery threshold SOCth, and the catalyst temperature of the exhaust gas purification catalyst is less than or equal to a predetermined first catalyst temperature threshold T1.

[0034] If a restart request is received during an automatic stop, the internal combustion engine 1 is restarted. In other words, if any of the aforementioned automatic restart conditions is met during an automatic stop of the internal combustion engine 1, the control unit 21 restarts the internal combustion engine 1. For example, if the battery SOC of the onboard battery is less than or equal to a predetermined battery threshold SOCth, the internal combustion engine 1 is restarted during an automatic stop.

[0035] Examples of automatic stops of the internal combustion engine 1 include an idle stop, a coast stop, and a cruise stop.

[0036] Idle stop is implemented when the vehicle temporarily stops, for example, when the above-mentioned automatic stop condition is established. In addition, for example, if any one of the above-mentioned automatic restart conditions is established, idling stop is cancelled.

[0037] Coast stop is performed while the vehicle is traveling, for example, when the aforementioned automatic stop conditions are met. Coast stop is also canceled, for example, if any of the aforementioned automatic restart conditions are met. Coast stop refers to automatically stopping the internal combustion engine 1 during deceleration, for example, when the brake pedal is depressed at low vehicle speeds.

[0038] Cruise stop is implemented while the vehicle is traveling, for example, when the aforementioned automatic stop conditions are met. Alternatively, cruise stop is canceled, for example, when any of the aforementioned automatic restart conditions are met. Furthermore, cruise stop automatically stops the internal combustion engine 1 during idling at medium to high vehicle speeds without the brake pedal depressed.

[0039] If a restart request is received during the engine speed reduction process of the internal combustion engine 1 due to an automatic stop, and if the engine speed of the internal combustion engine 1 is greater than or equal to a predetermined recovery combustion speed threshold R1 (speed threshold) that allows restarting only by fuel injection, the control unit 21 starts the internal combustion engine 1 by resuming fuel injection (combustion start). If the engine speed of the internal combustion engine 1 falls below the recovery combustion speed threshold R1, the control unit 21 rotates the crankshaft 2 using the alternator 6 to start the internal combustion engine 1 (cranking). Furthermore, if the engine speed falls below the recovery combustion speed threshold R1 during the engine speed reduction process of the internal combustion engine 1 due to an automatic stop, the control unit 21 controls the throttle valve 5 to reduce the amount of air introduced into the cylinder compared to before the engine speed fell below the recovery combustion speed threshold R1. In other words, the control unit 21 serves as a second control unit. The recovery combustion speed threshold R1 is, for example, approximately 600 rpm.

[0040] Therefore, with respect to the internal combustion engine 1, after the automatic stop condition is met, when the engine rotational speed is greater than or equal to the combustion resumable rotational speed threshold R1, the air amount in the cylinder can be ensured to respond to starting the internal combustion engine 1 (combustion start) by resuming fuel injection.

[0041] On the other hand, for the internal combustion engine 1, after the automatic stop conditions are met, when the engine rotational speed falls below the combustion-resumable rotational speed threshold R1, the amount of air introduced into the cylinders (the intake air amount) is reduced, thereby reducing the compression reaction force and suppressing the rotational fluctuation of the internal combustion engine 1. By reducing the amount of air introduced into the cylinders and reducing the compression reaction force, the internal combustion engine 1 can suppress vibrations when the engine rotational speed passes through a predetermined resonant frequency band (resonance domain) of the internal combustion engine 1.

[0042] This resonance frequency band corresponds to a rotational speed range lower than the internal combustion engine 1's idling speed (e.g., an internal combustion engine rotational speed of 300 to 500 rpm). That is, in the power transmission system of the internal combustion engine 1, there is a range where the internal combustion engine rotational speed is within the internal combustion engine resonance rotational speed upper limit R. U The lower limit value of the internal combustion engine resonant rotation speed R L The range between them is the resonance frequency band where resonance occurs.

[0043] Furthermore, if the internal combustion engine 1 is automatically stopped while the alternator 6 is generating electricity or the air conditioner is in use, the control unit 21 stops the alternator 6 from generating electricity or the air conditioner is in use, and controls the throttle valve 5 to reduce the amount of air entering the cylinder compared to before the alternator 6 or the air conditioner was stopped. Specifically, if the internal combustion engine 1 is automatically stopped while an auxiliary machine driven by the rotation of the crankshaft 2 of the internal combustion engine 1 is operating, the control unit 21 stops the auxiliary machine and controls the throttle valve 5 to reduce the amount of air entering the cylinder compared to before the auxiliary machine was stopped.

[0044] When the throttle valve 5 is closed to reduce the amount of air entering the cylinder (the amount of intake air), it is possible that the amount of air entering the cylinder cannot be fully reduced before the engine rotation speed passes through the resonant frequency band of the internal combustion engine 1 due to the responsiveness of the amount of air entering the cylinder and the deceleration of the internal combustion engine rotation speed.

[0045] Therefore, when the internal combustion engine 1 is automatically stopped, auxiliary devices such as the alternator 6 and the air conditioner are stopped to reduce the amount of air required for starting combustion. This allows the amount of air in the cylinder to be quickly reduced before the engine rotation speed passes through a predetermined resonance frequency band of the internal combustion engine 1.

[0046] After the engine rotation speed passes through the predetermined resonance frequency band of the internal combustion engine 1, the control unit 21 increases the amount of air introduced into the cylinder compared to when the engine rotation speed passes through the predetermined resonance frequency band of the internal combustion engine 1. That is, if the engine rotation speed is less than or equal to the engine resonance rotation speed lower limit value R L , the control unit 21 makes the air volume into the cylinder and the engine rotation speed be within the upper limit value R of the internal combustion engine resonance rotation speed. U The lower limit value of the internal combustion engine resonant rotation speed R L Increased compared to the time between.

[0047] After the engine speed passes through the resonant frequency band of the internal combustion engine 1, the influence of vibrations due to the compression reaction force decreases. Therefore, after the engine speed passes through the resonant frequency band of the internal combustion engine 1, the throttle valve 5 is opened to restore the amount of air entering the cylinders to the amount required for starting the internal combustion engine 1. This allows the internal combustion engine 1 to be quickly started when a restart request is issued.

[0048] Figure 2 1 is a timing chart showing the control state of the internal combustion engine 1 after the automatic stop condition is satisfied.

[0049] exist Figure 2 In the embodiment, the automatic stop condition is satisfied at time t1. At time t1, the automatic stop of the internal combustion engine 1 is permitted. When the automatic stop of the internal combustion engine 1 is permitted, the internal combustion engine 1 stops the fuel injection from the fuel injection valve.

[0050] exist Figure 2 In the example, the engine speed gradually decreases after time t1, passes through the resonant frequency band of internal combustion engine 1, and reaches "0" at time t6. The engine speed reaches the combustion recovery possible speed threshold R1 at time t2. The engine speed enters the resonant frequency band of internal combustion engine 1 at time t3 and leaves the resonant frequency band of internal combustion engine 1 at time t4.

[0051] exist Figure 2 At time t1 when the automatic stop condition is satisfied, the electromagnetic clutch 11 for the air conditioner (A / C clutch) is disengaged.

[0052] exist Figure 2 After time t1 when the automatic stop condition is satisfied, the alternator (ALT) 6 stops power generation (does not generate power).

[0053] If the automatic stop condition is met, the throttle valve 5 closes in accordance with the amount of reduction in the auxiliary load resulting from the cessation of power generation by the alternator 6 and the air conditioner. Specifically, at time t1, the throttle valve 5 closes so that the throttle opening is reduced in accordance with the amount of reduction in the load on the internal combustion engine 1 (auxiliary load) resulting from the auxiliaries that have been stopped as the automatic stop condition is met.

[0054] Then, after time t2 when the engine speed falls below the threshold value R1 for the resumable combustion speed, the throttle valve 5 is controlled to be fully closed until time t4 when the engine speed leaves the resonant frequency band of the internal combustion engine 1. That is, the throttle valve 5 is controlled so that if the engine speed falls below the threshold value R1 for the resumable combustion speed during the process of decreasing the engine speed of the internal combustion engine 1 due to the establishment of the automatic stop condition, the amount of air introduced into the cylinder is reduced compared to before the engine speed falls below the threshold value R1 for the resumable combustion speed.

[0055] At time t4, the throttle valve 5 is controlled to a predetermined large opening, that is, a predetermined first throttle opening O1. The first throttle opening O1 is an opening larger than the start-up throttle opening Os set when the internal combustion engine 1 is started.

[0056] That is, after the engine rotation speed of the internal combustion engine 1 passes through the resonance frequency band, the throttle valve 5 is controlled so as to increase the amount of air entering the cylinder compared to when the engine rotation speed of the internal combustion engine 1 passes through the resonance frequency band.

[0057] At time t5 , when the air pressure in the header pipe 4 reaches atmospheric pressure, the throttle valve 5 is controlled to the startup throttle opening Os.

[0058] Figure 3 1 is a flowchart showing the control flow of the internal combustion engine 1 according to the above-described embodiment.

[0059] In step S1, it is determined whether the automatic stop condition of the internal combustion engine 1 is satisfied and the automatic stop of the internal combustion engine 1 has been started. If the automatic stop of the internal combustion engine 1 has been started in step S1, the process proceeds to step S2. If the automatic stop of the internal combustion engine 1 has not been started in step S1, the current process ends.

[0060] In step S2 , auxiliary equipment such as the alternator 6 and the air conditioner are stopped to cut off (reduce) the load on the auxiliary equipment.

[0061] In step S3, the throttle valve 5 is closed in accordance with the amount of reduction in the auxiliary machine load. The greater the amount of reduction in the auxiliary machine load, the greater the amount of closing of the throttle valve 5.

[0062] In step S4, it is determined whether the engine speed is less than the combustion recovery possible speed threshold R1. If the engine speed is less than the combustion recovery possible speed threshold R1 in step S4, the process proceeds to step S5.

[0063] In step S5 , the throttle valve 5 is fully closed.

[0064] In step S6, it is determined whether the engine rotation speed is less than or equal to the engine resonance rotation speed lower limit value R L In step S6, the engine rotation speed is less than or equal to the lower limit value R of the engine resonance rotation speed. L In this case, go to step S7.

[0065] In step S7 , the throttle valve 5 is opened to a first throttle opening O1 which is a predetermined large opening so that the pressure (air pressure) in the header pipe 4 reaches atmospheric pressure in response to the restart.

[0066] In step S8, it is determined whether the pressure (air pressure) in the header pipe 4 has reached atmospheric pressure. If the pressure (air pressure) in the header pipe 4 has reached atmospheric pressure in step S8, the process proceeds to step S9.

[0067] In step S9 , the throttle valve 5 is set to the startup throttle opening Os.

[0068] Although the embodiments of the present invention have been described above, the present invention is not limited to the above embodiments, and various modifications can be made without departing from the spirit and scope of the present invention.

[0069] In the above embodiment, the opening of the throttle valve 5 is controlled to reduce the amount of air supplied to the cylinder when the internal combustion engine 1 is automatically stopped. However, if the internal combustion engine 1 has a variable valve mechanism that can change the valve timing of the intake valve, the variable valve mechanism can be used to reduce the amount of air supplied to the cylinder. In other words, the variable valve mechanism can be used as an air amount adjustment unit that adjusts the amount of air supplied to the cylinder.

[0070] During normal start-up of the internal combustion engine 1 by a driver's ignition key operation, the internal combustion engine 1 may be started by the alternator 6 , but may also be started by a dedicated starter motor separate from the alternator 6 .

[0071] That is, the internal combustion engine 1 may have a dedicated starter motor separate from the alternator 6 .

[0072] Furthermore, the above-described embodiments relate to a control method of an internal combustion engine and a control device of an internal combustion engine.

Claims

1. A method for controlling an internal combustion engine, wherein: If a predetermined automatic stop condition is met, fuel injection is stopped to automatically stop the internal combustion engine. If there is a request to restart the internal combustion engine during the process of the internal combustion engine rotation speed decreasing due to the automatic stop, if the internal combustion engine rotation speed is greater than or equal to a predetermined rotation speed threshold that can be restarted only by fuel injection, the internal combustion engine is started by resuming fuel injection. If the internal combustion engine rotation speed of the internal combustion engine is lower than the above-mentioned rotation speed threshold, the internal combustion engine is started by rotating the crankshaft using an electric motor, wherein the above-mentioned rotation speed threshold is higher than the rotation speed of the internal combustion engine that produces resonance. The air quantity adjustment unit is controlled in such a manner that, if the engine rotation speed of the internal combustion engine falls below the aforementioned rotation speed threshold value during a process of reduction in the engine rotation speed of the internal combustion engine due to an automatic stop, the air quantity adjustment unit adjusts the air quantity supplied to the cylinder so as to reduce the air quantity supplied to the cylinder compared to before the engine rotation speed falls below the aforementioned rotation speed threshold value. When the internal combustion engine is automatically stopped with the auxiliary machine in operation, the auxiliary machine is stopped and the amount of air introduced into the cylinder is reduced compared to before the auxiliary machine is stopped.

2. The internal combustion engine control method according to claim 1, wherein: After the engine rotation speed passes through a predetermined resonance frequency band of the internal combustion engine, the amount of air introduced into the cylinder is increased compared to when the engine rotation speed passes through the resonance frequency band.

3. A control device for an internal combustion engine, wherein: The control device of the internal combustion engine comprises: an electric motor that rotates the crankshaft to start the internal combustion engine; an air quantity adjustment unit capable of adjusting the quantity of air supplied to the cylinder; a first control unit that stops fuel injection to automatically stop the internal combustion engine if a predetermined automatic stop condition is satisfied; as well as The second control unit starts the internal combustion engine by resuming fuel injection when there is a request to restart the internal combustion engine during a process in which the internal combustion engine rotational speed is reduced due to an automatic stop, if the internal combustion engine rotational speed is greater than or equal to a predetermined rotational speed threshold value that allows restarting only by fuel injection, and starts the internal combustion engine using the electric motor if the internal combustion engine rotational speed is lower than the rotational speed threshold value, wherein the rotational speed threshold value is higher than the rotational speed of the internal combustion engine at which resonance occurs. The second control unit controls the air amount adjustment unit in such a manner that, if the engine rotational speed of the internal combustion engine falls below the rotational speed threshold value during a process in which the engine rotational speed of the internal combustion engine decreases due to the automatic stop, the amount of air supplied to the cylinder is reduced compared to before the engine rotational speed falls below the rotational speed threshold value. When the internal combustion engine is automatically stopped with the auxiliary machine in operation, the auxiliary machine is stopped and the amount of air introduced into the cylinder is reduced compared to before the auxiliary machine is stopped.

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