JP2022156373A - Control device for internal combustion engine - Google Patents

Abstract

To appropriately estimate the magnitude of an engine torque assumed to be outputted by an internal combustion engine mounted on a vehicle so as to maintain high performance of the vehicle.SOLUTION: A control device is used for controlling an internal combustion engine mounted on a vehicle. The control device is configured to, when obtaining magnitude of an engine torque assumed to be outputted by the internal combustion engine according to a current operation region of the internal combustion engine, if a predetermined condition to limit the engine torque, other than detection of occurrence of knocking, is not satisfied, obtain an assumed engine torque to which the limitation is not added, meanwhile, if the predetermined condition to limit the engine torque is satisfied, the control, obtain an assumed engine torque to which the limitation is added.SELECTED DRAWING: Figure 2

Description

The present invention relates to a control device for controlling an internal combustion engine mounted on a vehicle as a power source.

Today's vehicles are equipped with a plurality of Electronic Control Units. Specific examples include an EFI (Electronic Fuel Injection)-ECU that controls the operation of an internal combustion engine, including fuel injection and spark ignition, an ECU that operates and controls the driveline transmission, and an anti-lock braking system. ) or the vehicle stability control system (Vehicle Stability Control), the body ECU that controls the energization of lamps (lights) and wipers installed in the vehicle body, the ECU that controls the air conditioner that air-conditions the vehicle interior, etc. These ECUs are communicably connected via an electric communication line such as CAN (Controller Area Network), exchange necessary information with each other, and realize control of the entire vehicle (for example, the following patent See reference 1).

The EFI-ECU sets the spark ignition timing for the air-fuel mixture charged in the cylinder according to the operating range of the internal combustion engine. The base ignition timing is determined by comparing MBT (Minimum advance for Best Torque) in the operating range and the ignition timing limit (advanced angle amount) at which knocking is not normally considered to occur in the operating range. In the low load to medium load range, knocking does not occur even if the ignition timing is advanced to the MBT, so the MBT timing is used as the base ignition timing. On the other hand, in the high load region, there is a risk of knocking if the ignition timing is advanced to the MBT, so the base ignition timing needs to be delayed from the MBT timing.

In addition, the EFI-ECU determines the presence or absence of knocking in the cylinder and adjusts the ignition timing according to the determination result, which is a so-called knock control system. When knocking is detected, the ignition timing is gradually retarded until knocking no longer occurs, that is, the retardation correction amount added to the base ignition timing is gradually increased. When knocking is not detected, the ignition timing is gradually advanced as long as knocking does not occur. In other words, the amount of retardation correction added to the base ignition timing is decreased to improve the output and fuel efficiency of the internal combustion engine. For example, see Patent Document 2 below).

JP 2020-104552 A JP 2016-008578 A

The EFI-ECU, which controls the operation of the internal combustion engine, obtains the magnitude of the engine torque assumed to be generated as a result of the combustion of the air-fuel mixture in the combustion chamber of the cylinder. Then, the assumed engine torque is notified to other ECUs. Other ECUs use this to control transmissions, VSCs, and the like.

In principle, the assumed engine torque depends on the operating range of the internal combustion engine. In the memory of the EFI-ECU, the operating region [engine speed, engine load factor (that is, accelerator opening, intake pressure, intake air amount, fuel injection amount, etc.)] and the assumed engine torque under the operating region Stores map data that defines the relationship between The EFI-ECU searches the map using the parameters of the current operating range as a key to obtain the assumed engine torque.

When the driver of the vehicle does not depress the accelerator pedal and the engine speed is higher than a certain level, a fuel cut is executed to temporarily suspend fuel injection to the cylinders to suppress fuel consumption. As shown in FIG. 5, the EFI-ECU estimates the assumed engine torque in normal times when neither fuel cut nor engine torque limitation is performed (step S3) and when fuel cut is performed (step S6 or S8). switch the map data to be referenced.

In the conventional control, the assumed engine torque is obtained by formulating the map data without considering the adjustment of the ignition timing by the KCS. When the KSC is activated and the ignition timing is finely adjusted, the actual engine torque fluctuates. , whether or not the torque converter can be locked up), etc., may change instantaneously, resulting in a decrease in the drivability (or drive feeling) of the vehicle.

The EFI-ECU reduces the intake air amount and fuel injection amount (upper limit) filled in the cylinder when there is concern about overheating due to the temperature of the cooling water in the internal combustion engine being extremely high, or when the wheels are spinning. Overheating of the internal combustion engine and spinning of the wheels are avoided by restricting the engine torque by greatly retarding the ignition timing. As a result, retardation correction of ignition timing for the purpose of suppressing knocking by KCS and restriction of engine torque for the purpose of avoiding overheating of the internal combustion engine may overlap at the same time (abnormality such as knocking Combustion is more likely to occur as the temperature of the combustion chamber increases), which may cause at least one of the following problems.
A discrepancy occurs between the assumed engine torque obtained by the EFI-ECU and the engine torque actually output by the internal combustion engine. That is, as a result of the retardation of the ignition timing being weighted, the actual engine torque becomes smaller than the assumed engine torque. As the accurate engine torque value is not transmitted to other ECUs, the transmission control is not optimized, and the drivability and practical fuel efficiency of the vehicle deteriorate. At the moment of switching, the assumed engine torque fluctuates in a stepwise manner, causing a sudden change in the control of the transmission, etc., and the drivability and practical fuel consumption performance of the vehicle deteriorate. The intended purpose is to appropriately estimate the magnitude of the assumed engine torque and maintain high vehicle performance.

According to the present invention, there is provided a control device for controlling an internal combustion engine mounted on a vehicle.
If the predetermined conditions for limiting the engine torque are not met, except for the fact that the occurrence of knocking has been detected, the assumed engine torque without the limitation is obtained. A control device for an internal combustion engine is provided that, when a predetermined condition for limiting torque is satisfied, obtains an assumed engine torque with the limitation applied.

Further, according to the present invention, there is provided a control device for controlling an internal combustion engine mounted on a vehicle, in which, in determining the magnitude of the engine torque assumed to be output by the internal combustion engine according to the current operating range of the internal combustion engine, the knocking If a predetermined condition for limiting the engine torque other than the occurrence of is satisfied, the assumed engine torque with the limitation applied is obtained, and if the above condition is satisfied, the occurrence of knocking is detected. If the ignition timing is retarded due to the sensing, a control device for an internal combustion engine is configured to obtain reduced assumed engine torque according to the amount of retardation correction.

In addition, when the condition is satisfied and the engine torque is limited, the condition is not satisfied and the engine torque is not limited, or when the condition is not satisfied and the engine torque is limited. When the condition is satisfied and the engine torque is to be restricted from the state in which no torque is applied, it is preferable to gradually change the assumed engine torque instead of suddenly changing it stepwise.

ADVANTAGE OF THE INVENTION According to this invention, the magnitude|size of the engine torque which the internal combustion engine mounted in a vehicle presumes to output can be estimated appropriately, and the performance of a vehicle can be maintained highly.

1 is a diagram showing a schematic configuration of a vehicle internal combustion engine and a control device according to an embodiment of the present invention; FIG. FIG. 4 is a flow diagram showing an example of the procedure of processing executed by the control device according to the embodiment according to the program; FIG. 4 is a timing chart showing changes in assumed engine torque estimated by the control device of the embodiment; The flowchart which shows the procedure example of the process which a control apparatus performs according to a program in the modification of the same embodiment. FIG. 10 is a flowchart showing an example of a procedure of processing executed by a conventional control device according to a program;

One embodiment of the present invention will be described with reference to the drawings. FIG. 1 shows an outline of a vehicle internal combustion engine 100 according to this embodiment. The internal combustion engine 100 of the present embodiment is a port-injection four-stroke spark ignition engine, and includes a plurality of cylinders 1 (one of which is shown in FIG. 1). In the vicinity of the intake port of each cylinder 1, an injector 11 for injecting fuel toward the intake port is provided for each cylinder. A spark plug 12 is attached to the ceiling of the combustion chamber of each cylinder 1 . The spark plug 12 receives an induced voltage generated by an ignition coil and induces spark discharge between a center electrode and a ground electrode. The ignition coil is integrally built into the coil case together with the igniter, which is a semiconductor switching element.

An intake passage 3 for supplying intake air takes in air from the outside and guides it to the intake port of each cylinder 1 . An air cleaner 31, an electronic throttle valve 32 which is an intake throttle valve, a surge tank 33, and an intake manifold 34 are arranged in this order on the intake passage 3 from upstream.

An exhaust passage 4 for exhausting exhaust guides the exhaust generated as a result of burning fuel in the cylinder 1 from the exhaust port of each cylinder 1 to the outside. An exhaust manifold 42 and a three-way catalyst 41 for purifying exhaust gas are arranged on the exhaust passage 4 .

The exhaust gas recirculation device 2 includes an external EGR passage 21 that communicates the exhaust passage 4 and the intake passage 3, an EGR cooler 22 provided on the EGR passage 21, and an EGR passage 21 to open and close the EGR An EGR valve 23 for controlling the flow rate of EGR gas flowing through the passage 21 is included as an element. The inlet of the EGR passage 21 is connected to a predetermined location downstream of the catalyst 41 in the exhaust passage 4 . The outlet of the EGR passage 21 is connected to a predetermined location downstream of the throttle valve 32 in the intake passage 3 (in particular, the surge tank 33 or the intake manifold 34).

A transmission (not shown) interposed between the crankshaft, which is the output shaft of the internal combustion engine 100, and the driving wheels of the vehicle may be a known torque converter and an automatic transmission (stepped automatic transmission or stepless transmission). A transmission (Continuously Variable Transmission) may be used, or a manual transmission (Manual Transmission) may be used.

The EFI-ECU 0, which is a control device for the internal combustion engine 100, has a CPU (Central Processing Unit) 01, a RAM (Random Access Memory) 02, a ROM (Read Only Memory) 03 including a flash memory, an input interface 04, an output interface 05, and the like. It is a microcomputer system that A program to be executed by the CPU01 is stored in the ROM03, and when the program is executed, it is read from the ROM03 to the RAM02 and decoded by the CPU01. The EFI-ECU0 operates hardware resources according to a program to control the operation of the internal combustion engine 100. FIG.

The input interface 04 of the EFI-ECU 0 receives, for example, a vehicle speed signal a output from a vehicle speed sensor that detects the actual vehicle speed, and an output from a crank angle sensor that detects the rotation angle and engine speed of the crankshaft of the internal combustion engine 100. A crank angle signal b output from a sensor that detects the amount of depression of the accelerator pedal or the opening of the throttle valve 32 (so to speak, the engine load factor or the engine torque required for the internal combustion engine 100). c, Intake temperature/intake pressure signal output from a temperature/pressure sensor for detecting the intake air temperature and pressure in the intake passage 3 (downstream of the throttle valve 32, especially the surge tank 33 or the intake manifold 34) connected to the cylinder 1. d, a coolant temperature signal e output from a coolant temperature sensor for detecting the coolant temperature of the internal combustion engine 100, an atmospheric pressure signal f output from an atmospheric pressure sensor for detecting atmospheric pressure, and vibration of the cylinder block containing the cylinder 1. A vibration signal g output from a vibrating knock sensor that detects the magnitude of the knock, and a shift position signal h output from a shift position switch that detects the position of a shift lever (or selector lever) operated by the vehicle driver. etc. are entered.

From the output interface 05 of the EFI-ECU 0, an ignition signal i for the igniter attached to the spark plug 12, a fuel injection signal j for the injector 11, an opening operation signal k for the throttle valve 32, and an EGR valve 23 In response, an opening operation signal l or the like is output.

The EFI-ECU 0 calculates operating parameters and controls the operation of the internal combustion engine 100 . The EFI-ECU 0 acquires various types of information a, b, c, d, e, f, g, and h necessary for control through an input interface, and ascertains the engine speed and the air intake into the cylinder 1 ( fresh air) amount. Then, the required fuel injection amount (which can achieve the stoichiometric air-fuel ratio or a target air-fuel ratio near it) that matches the intake air amount, the fuel injection timing (including the number of fuel injections for one combustion), the fuel injection pressure, Various operating parameters such as ignition timing (including the number of times of ignition for one combustion), required EGR rate (or EGR gas amount, EGR gas partial pressure), etc. are determined. The EFI-ECU 0 applies various control signals i, j, k, l corresponding to operating parameters through an output interface.

The EFI-ECU 0 is connected to a bus of electric communication lines such as CAN installed in the vehicle, and is connected to other ECUs, that is, the ECU 5 that controls the transmission of the drive system of the vehicle, the ECU 6 that controls the ABS or VSC, and the vehicle body. A body ECU 7 for controlling energization of lamps, wipers, etc. installed in the vehicle, an ECU 8 for controlling an air conditioner for air-conditioning the interior of the vehicle, and the like can perform mutual data communication.

The EFI-ECU 0, which controls the operation of the internal combustion engine 100, sets the base ignition timing according to the current operating range of the internal combustion engine 100 when determining the spark ignition timing of the air-fuel mixture charged in the cylinder 1, A retard correction amount is added to the base ignition timing according to the presence or absence of knocking in the combustion chamber of the first cylinder.

The base ignition timing is determined at a timing at which the possibility of knocking that can be perceived by human hearing is small and the thermomechanical conversion efficiency of the internal combustion engine 100 can be maximized. The base ignition timing in the partial load region where the accelerator opening is not large is the MBT or its vicinity. The base ignition timing in the full-load or high-load region where the accelerator opening is fully open or nearly fully open lags MBT. In the RAM 02 or ROM 03 of the EFI-ECU 0, parameters indicating the operating range of the internal combustion engine 100 [engine speed, engine load factor (that is, accelerator opening, intake pressure of surge tank 33 or intake manifold 34, intake air amount or fuel injection amount, etc.)] and the base ignition timing. The EFI-ECU 0 retrieves the map data using the current operating range parameter of the internal combustion engine 100 as a key to obtain the base ignition timing to be set. By the way, the intake pressure, which is the key to search the map data, may be the one that takes into account the correction due to the current atmospheric pressure. g is referred to determine whether or not there is knocking in each cylinder 1, and the ignition timing is adjusted according to the determination result. The EFI-ECU 0 samples the vibration signal g indicating the strength of the vibration of the cylinder 1 or the cylinder block, and passes the frequency component (for example, 7 kHz to 15 kHz component) of the vibration caused by knocking, and extracts the vibration. input to a bandpass filter that attenuates components other than Then, the value of the signal g after being processed by the bandpass filter is compared with the knock determination value, and if the former exceeds the latter, it is determined that knocking has occurred in cylinder 1 in the expansion stroke. If the former is less than or equal to the latter, it is determined that the cylinder 1 is not knocking.

When the occurrence of knocking in cylinder 1 is sensed, the ignition timing is gradually retarded until knocking no longer occurs, in other words, the retardation correction amount added to the base ignition timing is gradually increased. On the other hand, when the occurrence of knocking is not detected, the ignition timing is gradually advanced as long as knocking does not occur. Improve performance. The determination of the presence or absence of knocking and the correction of the ignition timing can be performed individually for each cylinder.

Also, the EFI-ECU 0 executes a fuel cut to temporarily interrupt the fuel supply to the cylinder 1 when a predetermined fuel cut condition is satisfied. The EFI-ECU 0 determines that at least the cooling water temperature of the internal combustion engine 100 has already risen to a predetermined lower limit value or more, the accelerator opening is 0 or a threshold close to 0 or less, and the current engine speed is the fuel cut permission rotation. It is determined that the fuel cut condition is established when the value is higher than the number.

Even if the fuel cut condition is satisfied, the fuel injection from the injector 11 is not necessarily stopped immediately. In order to suppress or reduce the torque shock caused by the fuel cut, the EFI-ECU 0 waits for the delay period to elapse or the engine torque to drop after the fuel cut condition is satisfied before stopping the fuel injection. During the delay period, the spark ignition timing for the air-fuel mixture filled in the cylinder 1 is retarded from the base ignition timing, or fuel injection (and fuel (ignition combustion) may be suspended to actively reduce the engine torque.

After the fuel cut condition is satisfied, if a predetermined fuel cut termination condition is satisfied, the fuel cut is terminated and the fuel injection from the injector 11 is restarted. The EFI-ECU 0 determines that the fuel cut end condition is met when the accelerator opening exceeds a threshold, or when the engine speed falls below the fuel cut return speed.

Note that the EFI-ECU 0 detects the engine torque output by the internal combustion engine 100 (or (upper limit) may be imposed. The predetermined condition is, for example, that the temperature of the cooling water of the internal combustion engine 100 exceeds a predetermined upper limit value and is remarkably high, or that the EFI-ECU 0 is notified by the VSE-ECU 6 that the wheels are currently spinning. It may be that you are receiving a notification. When the engine torque is limited, the opening of the throttle valve 32 is reduced (or the upper limit of the opening is lowered), or the amount of fuel injected from the injector 11 is reduced ( Alternatively, the upper limit of the fuel injection amount may be lowered from the normal time), or the ignition timing may be retarded more than the normal time (in addition to the retardation correction by the KCS that refers to the output signal g of the knock sensor). Execute at least one of them.

The EFI-ECU 0 of this embodiment estimates the magnitude of the engine torque that the internal combustion engine 100 is expected to output. This assumed engine torque can also be regarded as a target value of the engine torque that the internal combustion engine 100 should output. The assumed engine torque can affect the opening of the throttle valve 32 operated by the EFI-ECU 0, the amount of air taken into the cylinder 1, the amount of fuel injected from the injector 11 to the cylinder 1, the ignition timing, and the like. If there is a difference between the required engine torque based on the amount of depression of the accelerator pedal by the driver and the assumed engine torque, the difference is reduced (the assumed engine torque from this point onwards approaches the required engine torque. ), the opening of the throttle valve 32, the amount of fuel injection, and/or the ignition timing are adjusted.

In addition, the EFI-ECU 0 notifies the other ECUs 5, 6, 7, 8 of the assumed engine torque value. The other ECUs 5, 6, 7, 8 that have received this information, according to the amount of assumed engine torque, determine the gear ratio or gear stage realized by the transmission of the drive system of the vehicle, whether or not the torque converter can be locked up, the internal combustion engine 100 It adjusts the output, etc. of the compressor for compressing the refrigerant, which is driven by the crankshaft.

FIG. 2 or FIG. 4 shows the procedure for calculating the assumed engine torque by the EFI-ECU 0 of this embodiment. The EFI-ECU 0 is currently not executing a fuel cut (step S1), and there are no circumstances requiring engine torque limitation, such as an increase in the temperature of the cooling water or spinning of the wheels (step S2). The engine torque assumed to be output by the internal combustion engine 100 is obtained based on the operating range of the internal combustion engine 100, the spark ignition timing of the air-fuel mixture, and the like.

The RAM 02 or ROM 03 of the EFI-ECU 0 prestores the relationship between the parameters indicating the operating range of the internal combustion engine 100 [engine speed, engine load factor (i.e., intake pressure, etc.)] and the basic amount of normal assumed engine torque. Stores map data that defines The EFI-ECU 0 searches the map data using the parameters of the current operating range of the internal combustion engine 100 as a key, and obtains the basic amount of assumed engine torque (step S3). By the way, the intake pressure, which is the key for retrieving the map data, may be corrected according to the current atmospheric pressure.

Furthermore, as shown in FIG. 4, the EFI-ECU 0 modifies the basic amount of assumed engine torque to reflect the thermomechanical conversion efficiency corresponding to the current spark ignition timing (step S4). good too. The ignition timing referred to here may be the one to which the retardation correction by the KCS is added. The thermomechanical conversion efficiency decreases as the ignition timing is retarded from the MBT. Therefore, in step S4, the EFI-ECU 0 determines that the greater the retardation amount of the current ignition timing from the base ignition timing or the MBT corresponding to the current operating region of the internal combustion engine 100, the more the basic amount of assumed engine torque The final assumed engine torque is calculated by subtracting or subtracting the torque value from .

However, the step S4 is not essential, and it may be better not to make such modifications. This is because when the KSC operates and the ignition timing is finely adjusted, the actual engine torque output by the internal combustion engine 100 fluctuates. This is because transmission to 6, 7, and 8 may cause momentary fluctuations in the control of the transmission and the like, resulting in deterioration of the drivability of the vehicle.

Even during execution of fuel cut (step S1), the EFI-ECU 0 determines that the internal combustion engine 100 outputs based on the current operating range of the internal combustion engine 100 and the spark ignition timing to the air-fuel mixture. Obtain the assumed engine torque.

The RAM 02 or ROM 03 of the EFI-ECU 0 stores in advance map data defining the relationship between a parameter indicating the operating range of the internal combustion engine 100 and the basic amount of assumed engine torque during fuel cut. This map data is formulated separately from the normal map data. In addition, the map data to be referred to differs depending on whether fuel cut is currently being executed in all cylinders 1 of the internal combustion engine 100 or fuel cut is being executed only in some cylinders 1 (step S5) (step S6 or S8). Naturally, when fuel cut is being executed in all cylinders 1, the engine torque output from the internal combustion engine 100 is 0 or close to 0. The EFI-ECU 0 searches the map data using the parameters of the current operating range of the internal combustion engine 100 as a key to obtain the basic amount of assumed engine torque (step S6 or S8). The intake pressure, which is the key to search for map data, may be the one that takes into account the correction due to the current atmospheric pressure.

Even during execution of fuel cut, as shown in FIG. 4, the EFI-ECU 0 modifies the basic amount of assumed engine torque to reflect the thermomechanical conversion efficiency according to the current spark ignition timing ( Step S7) may be performed. The ignition timing referred to here may be the one to which retardation correction by the KCS is added. In step S7, the EFI-ECU 0 determines that the greater the amount of retardation of the current ignition timing from the base ignition timing or MBT corresponding to the current operating range of the internal combustion engine 100, the greater the torque shift from the base amount of assumed engine torque. The value is discounted or subtracted to determine the final expected engine torque.

However, like step S4, step S7 is not essential, and it may be better not to make such a correction. Also, when fuel cut is being executed in all cylinders 1 (step S5), it is not necessary to reflect the ignition timing for calculating the assumed engine torque. In the first place, in cylinder 1 during fuel cut, there is a possibility that the spark plug 12 is not performing spark discharge (in order to keep the spark plug 12 warm, spark discharge may continue even during fuel cut).

On the other hand, the EFI-ECU 0 increases the output of the internal combustion engine 100 compared to the normal time when a predetermined condition for executing engine torque limitation, such as an increase in the temperature of the cooling water or idling of the wheels, is satisfied (step S2). engine torque (or its upper limit) to be reduced. At the same time, the engine torque assumed to be output by the internal combustion engine 100 is obtained based on the current operating range of the internal combustion engine 100 and the like.

The RAM 02 or ROM 03 of the EFI-ECU 0 stores in advance map data that defines the relationship between the parameters indicating the operating range of the internal combustion engine 100 and the assumed engine torque when the engine torque is limited. This map data is prepared separately from the map data for normal operation and the map data for fuel cut. Assuming that the operating range [engine speed, engine load factor (i.e., intake pressure, etc.)] is the same, the engine torque at the time of engine torque limit will be lower than that at normal times unless the ignition timing retardation correction by KCS is taken into account. Engine torque (basic amount) or less. The EFI-ECU 0 retrieves the map data using the current operating range parameter of the internal combustion engine 100 as a key to obtain an assumed engine torque (step S9). The intake pressure, which is the key to search for map data, is sometimes corrected for the current atmospheric pressure.

However, in this case, there is a possibility that the reduction of engine torque accompanying retardation correction of the ignition timing by KCS is further weighted by engine torque limitation. Therefore, when the engine torque is limited, it is desirable to correct the assumed engine torque according to the spark ignition timing at that time. Therefore, as shown in FIG. 2 or 4, the EFI-ECU 0 modifies the basic amount of assumed engine torque to reflect the thermomechanical conversion efficiency according to the current spark ignition timing (step S10). The ignition timing referred to here may be the one to which the retardation correction by the KCS is added. The EFI-ECU 0 discounts or reduces the torque value from the assumed engine torque base amount as the current ignition timing is retarded from the base ignition timing or MBT corresponding to the current operating range of the internal combustion engine 100. Then, the final assumed engine torque is calculated.

Of course, the engine torque is limited (step S2), but the ignition timing is not retarded by the KCS due to the detection of knocking (that is, the ignition timing is retarded by the KCS). is less than a predetermined value (which may be 0 or close to 0)), it is permitted to obtain the assumed engine torque exclusively from the above map data (step S9). In short, there is no need to add a correction (step S10) to reflect the thermomechanical conversion efficiency according to the current spark ignition timing.

Even if a predetermined condition for executing engine torque limitation is satisfied (step S2), the ignition timing is retarded due to the detection of knocking (that is, by KCS). When the retardation correction amount of the ignition timing is equal to or greater than a predetermined value, the engine torque limit may not be intentionally executed, and the assumed engine torque may be obtained in the same manner as in normal times (steps S3 and S4). In other words, instead of the map data for when the engine torque is limited, refer to the map data for normal times to obtain the basic amount of the assumed engine torque, correct it according to the current ignition timing, and obtain the final assumed engine torque. Calculate. This means that the engine torque limitation is canceled and only the retardation correction of the ignition timing by the KCS is performed to avoid overheating of the internal combustion engine 100 and spinning of the wheels.

The EFI-ECU 0 that has calculated the assumed engine torque transmits the engine torque value to other ECUs 5, 6, 7, 8 via electric communication lines such as CAN.

The EFI-ECU 0 of the present embodiment uses map data to refer to to obtain the assumed engine torque in each of normal operation (step S3), fuel cut (step S6 or S8), and engine torque limitation (step S9). switch. Therefore, when transitioning between the state where fuel cut is not executed and the state where it is executed, or when transitioning between the state where engine torque limitation is not executed and the state where it is executed, the calculated assumed engine torque There is a possibility that the value of will suddenly change stepwise. A sudden change in the value of the assumed engine torque notified from the EFI-ECU 0 to the other ECUs 5, 6, 7, 8 is not preferable because it leads to a sudden change in the gear ratio realized by the transmission of the driving system.

Therefore, the EFI-ECU 0 of the present embodiment changes between a state where the fuel cut is not executed and a state where the fuel cut is executed, and/or between a state where the engine torque limitation is not executed and a state where the engine torque limit is executed. When transitioning between, smoothing processing (or low-pass filtering) is performed so as to gradually change the value of the assumed engine torque.

The pattern is illustrated in FIG. _In FIG. ₃ , before time t1, the operating state is normal, and at time t1, engine torque limitation (or fuel cut) is started, and at _time t2, the engine torque limitation (or fuel cut) is started. and then return to normal operation. The dashed line represents the transition of the assumed engine torque without smoothing, which is obtained by the EFI-ECU 0 referring to the map data, and the solid line represents the transition of the assumed engine torque after smoothing. ing. While the former fluctuates stepwise, the latter converges to the former value while changing more moderately. The EFI-ECU 0 notifies the other ECUs 5, 6, 7 and 8 of the value of the assumed engine torque that gradually changes as drawn by the solid line.

The length of the period during which the assumed engine torque is gradually changed after the state transition times t1 and t2 is, for example, about 0.5 seconds to _{1 second} . Immediately after the time points t ₁ and t ₂ when the state transitions, the amount of change in the assumed engine torque per unit time or unit calculation cycle, that is, the absolute value of the amount of decrease or increase, is large. Then, as time elapses from the time points t ₁ and t ₂ , the amount of change per unit time or unit operation cycle is made smaller.

The amount of change in the assumed engine torque per unit time or unit calculation cycle may be adjusted according to the deviation between the assumed engine torque at that time and the actual engine torque actually output by the internal combustion engine 100. In that case, the larger the absolute value of the deviation between the assumed engine torque and the actual engine torque, the larger the absolute value of the amount of change in the assumed engine torque per unit time or unit calculation cycle. In the EFI-ECU 0, the actual engine torque can be estimated from the actual intake air amount to cylinder 1 and the actual fuel injection amount according to a known method. If necessary, the actual engine torque may be estimated in consideration of the engine speed (motion speed of the piston reciprocating in cylinder 1).

In this embodiment, the control device 0 for controlling the internal combustion engine 100 mounted on the vehicle senses the occurrence of knocking when determining the magnitude of the engine torque assumed to be output by the internal combustion engine 100. If the predetermined condition for limiting the engine torque is not satisfied, the assumed engine torque without the limitation is obtained (step S3). When a predetermined condition to be limited is established (step S2), the control device 100 for the internal combustion engine is configured to obtain the assumed engine torque with the limitation applied (step S9).

In addition, when the control device 0 satisfies a predetermined condition for restricting the engine torque other than the detection of the occurrence of knocking (step S2), the control device 0 obtains the assumed engine torque with the restriction applied (step S9). ), and if the ignition timing is retarded due to the detection of the occurrence of knocking when the above conditions are satisfied, then it is assumed that the ignition timing is reduced according to the retardation correction amount. The engine torque is obtained (step S10).

Moreover, when the control device 0 transitions from a state in which the condition is satisfied and the engine torque is limited (step S9) to a state in which the condition is not satisfied and the engine torque is not limited (step S3), Alternatively, when the condition is not satisfied and the engine torque is not limited (step S3) to the condition is satisfied and the engine torque is limited (step S9), as shown in FIG. Thus, the assumed engine torque is gradually changed without being suddenly changed in a stepwise manner.

When the ignition timing is retarded by the function of KSC, the control device 0 takes into consideration the decrease in the thermomechanical conversion efficiency due to the retardation correction, and obtains a more accurate assumed engine torque (step S3). and S4, S6 and S7, or S9 and S10). Therefore, the difference between the assumed engine torque and the actual engine torque is reduced, and the control by the other ECUs 5, 6, 7, 8, typically the gear ratio of the transmission, the lockup control of the torque converter, etc., are optimized. . As a result, it is possible to maintain high drivability and practical fuel consumption performance of the vehicle.

Even if conditions for engine torque limitation, such as an increase in coolant temperature or wheel slip, are met (step S2), the KCS has already retarded the ignition timing to a certain extent or more. If so, the engine torque limitation may be canceled without being executed. Since it is avoided that the engine torque is reduced due to the retardation correction of the ignition timing, further engine torque limitation is avoided, so that the vehicle can always exhibit the required acceleration performance. The sluggish start and acceleration of the vehicle can be alleviated, and the fuel consumption can be prevented from unreasonably increasing due to a dissatisfied driver depressing the accelerator pedal strongly. In addition, the gap between the assumed engine torque (step S3 and FIG. 4) when the engine torque is not limited and the assumed engine torque when the engine torque is limited (step S9) becomes smaller. . As a result, sudden changes in the gear ratio of the transmission and the like are avoided when the engine torque limitation is changed from a state in which it is not executed to a state in which it is executed, or vice versa.

The present invention is not limited to the embodiments detailed above. Various modifications can be made to the specific configuration of each part, the procedure of processing, and the like without departing from the spirit of the present invention.

DESCRIPTION OF SYMBOLS 100... Internal combustion engine 1... Cylinder 11... Injector 12... Spark plug 3... Intake passage 32... Throttle valve 0... Control device (EFI-ECU) of an internal combustion engine
b Crank angle signal c Accelerator opening signal d Intake air temperature/intake pressure signal e Cooling water temperature signal f Atmospheric pressure signal g Knock sensor output signal i Ignition signal j Fuel injection signal k Throttle valve Opening operation signal

Claims (3)

A control device for controlling an internal combustion engine mounted on a vehicle,
In determining the magnitude of the engine torque assumed to be output by the internal combustion engine according to the current operating range of the internal combustion engine,
If a predetermined condition for limiting the engine torque other than the fact that knocking has been sensed does not hold, then the assumed engine torque without the limitation is obtained.
A control device for an internal combustion engine that, when a predetermined condition for limiting engine torque other than the detection of knocking is satisfied, obtains assumed engine torque with the limit applied. A control device for controlling an internal combustion engine mounted on a vehicle,
In determining the magnitude of the engine torque assumed to be output by the internal combustion engine according to the current operating range of the internal combustion engine,
when a predetermined condition for limiting the engine torque other than the detection of the occurrence of knocking is met, obtaining the assumed engine torque with the limitation applied;
In addition, if the ignition timing is retarded due to the detection of knocking when the above condition is satisfied, the assumed engine torque that is reduced according to the retardation correction amount is performed. A control device for an internal combustion engine that requires When the condition is satisfied and the engine torque is limited, the condition is not satisfied and the engine torque is not limited, or the condition is not satisfied and the engine torque is not limited. 3. A control system for an internal combustion engine according to claim 1, wherein when the same condition is established and the state is changed to a state in which the engine torque is limited, the assumed engine torque is gradually changed without being suddenly changed in a stepwise manner.

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