JP3488931B2 - Control method and control device for internal combustion engine for vehicle - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a control method and a control device for an internal combustion engine for a vehicle.

[0002]

2. Description of the Related Art In an internal combustion engine (engine) of a vehicle,
In addition to a device that increases or decreases the engine torque in conjunction with the accelerator pedal operated by the driver, there is a system that can control the engine torque by a control signal from the controller. Are known.

Further, for example, in a vehicle equipped with an automatic transmission (A / T), a torque converter for transmitting engine output torque is provided with a torque increasing function and torque fluctuation for the purpose of improving fuel efficiency by improving transmission efficiency. Under vehicle operating conditions in the lockup area where absorption function is not required,
Some include a lock-up device that can be set to a directly connected lock-up state instead of a converter state.

[0004] On the other hand, the applicant of the present invention, Japanese Patent Laid-Open No. 57-1
As disclosed in Japanese Patent No. 61358, a technique for engine stall avoidance control in coast lockup has been proposed.

[0005]

In order to prevent the engine stall (stalling) during braking, this is to release the lock-up clutch at the time when it is judged to be a sudden braking, and when it is not judged to be a sudden braking. Control the lock-up clutch to continue without releasing the lock-up clutch. According to this, in the control of the engine loaded with the torque converter and the lockup device, it is expected that the engine resistance will be improved as compared with the case where the technology is not adopted.

However, when considering the following points, there is still room for improvement. When the vehicle is traveling, for example, when the road surface is a low μ road, sudden braking may cause the tire to lock within a short period of time, for example, about 0.1 seconds after the braking starts. In the situation where such a wheel lock is seen, as will be discussed later, when the lockup clutch is switched from engagement to release, the engagement torque capacity gradually decreases and is released, but this is usually a problem. Such an opening delay that does not occur is also a big problem for such a high speed phenomenon.

From the standpoint of always achieving stable stalling resistance, even in the case where the torque transmission system is provided with the lock-up clutch whose engagement and non-engagement is controlled as described above, the wheel lock is observed. In order to prevent the engine stall even in such a situation, it is necessary to increase the disengagement speed of the lockup clutch in the state of direct connection between the input and output elements, but this has a limit. Therefore, in such a vehicle, it is necessary to compensate for this delay amount in order to obtain the same stalling resistance as when the lockup clutch is not engaged.

Further proceeding, not only the load due to the delay in opening the lockup but also other load factors are taken into consideration to adjust the torque generated by the engine (internal combustion engine) according to the load, so that the engine stability can be stabilized. It becomes an important requirement to obtain. If this can be realized, it is possible to compensate for all the load torque applied to the engine, and a high degree of adaptability can be obtained.

The present invention has been made in view of the above points, and it is intended that the engine stall resistance can be stably secured and the engine stall resistance can be improved. It is a thing. And for other purposes,
Suitable for application in control of a vehicle internal combustion engine to which a torque converter and a lockup device are loaded, even for load factors due to a lockup opening delay during sudden braking, the above can be appropriately realized. It is to provide improved control.

[0010]

According to the present invention, the following control method and control device for a vehicle internal combustion engine are provided. That is, in addition to the first device that increases or decreases the torque of the internal combustion engine in conjunction with the accelerator pedal operated by the driver of the vehicle, a second device that controls the torque of the internal combustion engine based on a signal from the electronic control device is provided. In a vehicle internal combustion engine equipped with the internal combustion engine, the rotational speed of the internal combustion engine is input, and is varied from the difference between the target rotational change rate estimated based on the difference between the generated torque and the load torque of the internal combustion engine and the actual rotational change rate. A method of controlling an internal combustion engine for a vehicle, comprising calculating a power torque, and controlling the generated torque of the internal combustion engine by the second device according to the calculated torque. This control method is also characterized in that the torque to be varied is calculated from the difference between the target rotation change rate and the actual change rate and the rotation speed of the internal combustion engine.

Further, a first device for increasing / decreasing the torque of the internal combustion engine in conjunction with an accelerator pedal operated by the driver of the vehicle, and a second device for controlling the torque of the internal combustion engine based on a signal from the electronic control unit. A control device for a vehicle internal combustion engine comprising: a first device in a minimum output demand state, a target value of a speed-time differential value of the rotational speed of the internal combustion engine is calculated, A control device for an internal combustion engine for a vehicle, comprising means for determining a torque variable command value of the second device based on a difference between a target value and an actual differential value. Further, in the above, the vehicle includes a torque converter that amplifies the torque of the internal combustion engine and transmits the torque to the transmission mechanism, and a lockup clutch that is arranged in parallel with the torque converter that is controlled to be engaged or disengaged by the electronic control unit. A vehicle equipped with a control device for an internal combustion engine for a vehicle, characterized in that the control method is used when a lock-up clutch is not engaged, and a means for detecting a sudden braking. The control device for the internal combustion engine for a vehicle is characterized in that different values are applied as the variable torque command value depending on the case. Also,
The torque control by the second device is performed either by controlling the intake air amount, or by controlling at least one of fuel supply control and ignition timing control in place of or in addition to the intake air amount control. And a control device for an internal combustion engine for a vehicle, wherein the intake air amount control is an auxiliary air control or an intake air amount control including at least the auxiliary air control. It is the control device of the engine.

[0012]

With the above configuration, it is possible to compensate for various load torques applied to the internal combustion engine at the time of the corresponding control in order to avoid engine stall, and the generated torque of the internal combustion engine can be adjusted according to the load. Even if there is a torque increment due to the lock-up opening delay during sudden braking, not only that but also the generated torque corresponding to the entire load of the internal combustion engine is given, so the engine stall performance is stable and reliable. It is possible to secure stable engine stall resistance. Further, in claim 2, the torque to be varied is calculated from the difference between the target rotation change rate and the actual change rate and the rotation speed of the internal combustion engine, and the engine stall resistance is further improved. It is possible to secure a stable supply.

According to a third aspect of the present invention, a first device that increases or decreases the torque of the internal combustion engine in conjunction with the accelerator pedal and a second device that controls the torque of the internal combustion engine based on a signal from the electronic control device. And a means for determining the torque variable command value of the second device, which makes it possible to realize a control device which also enables the above.

Further, in the case where the torque converter and the lock-up clutch are provided as described in claim 4, when the control by the second device is applied when the lock-up clutch is not engaged, in addition to the above, provisionally There is no slippage of the converter.If control is performed while the lockup is engaged, deterioration of drivability due to generation of vehicle acceleration torque against the driver's intention, etc. will be avoided. In addition, it is possible to effectively improve the engine stall resistance while ensuring the drivability without causing an empty space or depression. In addition, the engine stall performance is stable and reliable, and the engine stall on low μ roads can be appropriately avoided when coasting, so you can engage the lockup clutch during coasting and compare when not coasting up. Then, since the increase in the rotation of the internal combustion engine is suppressed when the pedal is depressed again, it is possible not only to maximize the fuel consumption improving effect and also to make its original action more effective. Since the number of times lock-up is turned on and off can be reduced, it is possible to improve the durability of the lock-up device such as lock-up facing, and particularly to control the internal combustion engine for a vehicle loaded with the torque converter and the lock-up device. Is effective in. In addition to the above, in addition to the above, in the case of sudden braking,
It is possible to use a command value that is different from the one used when the brakes are not suddenly applied, to implement this control, and to perform more detailed control. It is possible to easily use different values such as using a woven value, and it is possible to avoid deterioration of drivability during normal driving other than sudden braking.
Further, as described in claim 6 or claim 7, regarding the torque control by the second device, the fuel supply control and the ignition timing by the intake air amount control, instead of or in addition to the intake air amount control. With any of the aspects of at least one of the controls, and
In this case, the present invention can be implemented in a mode in which the intake air amount control is the auxiliary air control, or at least the intake air amount control including the auxiliary air control, and similarly, the above is enabled.

[0015]

Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 shows the system configuration of an embodiment of the present invention.
In the figure, 1L and 1R are left and right front wheels of the vehicle, 2L and 2R are left and right rear wheels, and 11 is an engine (internal combustion engine).
The engine 11 is, for example, a four-cylinder engine whose fuel supply, ignition timing, etc. are electronically controlled by an engine control system.
It is a drive-type FR vehicle that drives the rear two wheels 2L and 2R, which are the drive wheels.

The output torque of the engine 11 is transmitted from the engine output shaft through a transmission, for example, an automatic transmission (A / T) 12, and a differential gear 13 to the drive wheels 2L, 2L.
It is transmitted to R. The automatic transmission 12 inputs the output of the engine 11 to the differential gear 13 and thereby drives the left and right rear wheels 2L, 2R. Further, reference numeral 15 in the drawing denotes an engine control unit (engine controller),
Reference numeral 16 is an automatic transmission control unit (A / T controller).

The automatic transmission 12 includes a torque converter that amplifies the torque of the engine 11 and transmits it to the speed change mechanism, and a lockup clutch that is arranged in parallel with a torque converter that is controlled to be engaged or disengaged by an electronic control unit. It can be equipped with.

In FIG. 2, the automatic transmission 12 comprises a torque converter 40 for transmitting the rotation of the engine output shaft, a speed change mechanism 41, friction elements such as clutches and brakes, a control valve section 42 as a hydraulic control device, and the like. Shown as one. Here, the transmission input rotation is geared at a gear ratio (gear ratio corresponding to the selected gear) according to the vehicle running state and reaches the output shaft 43, and the engine output is driven through the differential gear 13 at that gear ratio. The wheels 2L, 2R are reached, which allows the vehicle to travel. The control valve unit 42 forms a shift control hydraulic circuit including various control valves (valves), a line pressure solenoid, a shift solenoid, and the like. Lock up (L
/ U) mechanism, the hydraulic circuit includes a lockup control valve, a lockup solenoid, and the like.

The lockup mechanism will be described below. Generally, the lockup mechanism adopts a structure for engaging the lockup clutch by increasing the apply chamber pressure between the lockup clutch and the turbine more than the release chamber pressure between the lockup clutch and the torque converter cover (for example, Nissan. Maintenance Manual A261C14 A-
(From page 2).

In the structure of the lockup mechanism shown in FIG. 3, the lockup clutch 45 has a left portion in the drawing, that is, a portion surrounded by the lockup clutch and the torque converter cover (torque converter cover) 46 (release chamber side). )
From the pressure (release pressure) on the right side, that is, the lock-up clutch 45 and the turbine (turbine runner) 47.
The lock-up clutch 45 is fastened to the torque converter cover 46 by increasing the pressure (apply pressure) in the portion (apply chamber side) surrounded by and. The lock-up clutch 45 has a clutch fading fixed to the surface facing the torque converter cover 46. Further, by increasing the release pressure of the lockup clutch 45 above the apply pressure, a flow is created from the left side to the right side in the drawing, and the lockup clutch 45 is released from the torque converter cover 46.

Such pressure switching can be performed based on an electric signal from the electronic control unit sent to the hydraulic control unit (for example, page A-80 of the maintenance manual A261C14). .

FIG. 3 also shows a simplified example of an example of the hydraulic control unit. The hydraulic circuit system includes a lockup control valve 48 (lockup control valve (L
11)) and a lockup solenoid (SL) 49 are provided, and the control unit 16 gives a drive control signal to the lockup solenoid 49. Here, the device for generating the operating pressure used in the hydraulic control device may be the oil pump 50 whose drive source is the engine 11 (page A-2 of the maintenance manual A261C14). The hydraulic oil discharged by the oil pump 50 is regulated by the regulator valve (L1) 51, and the line pressure is created by this.

The outline of engagement and disengagement of the lockup clutch (lockup engagement (ON), non-engagement (OFF)) is as follows.
It looks like this: When the lockup control valve 48 is switched to one side by an electric signal (control signal) to the lockup solenoid 49, a circuit from the line pressure oil passage to the lockup control oil passage to the apply pressure oil passage is formed, and the release pressure oil passage is formed. Is composed of oil cooler → rear lubrication → drain circuit. When the lockup control valve 48 is switched to the other,
The line pressure oil passage → lockup control oil passage → release pressure oil passage → apply pressure oil passage → oil cooler → rear lubrication → drain circuit.

In FIG. 2, when the torque converter 40 includes the lockup mechanism as described above, when the lockup clutch 45 is engaged (during operation), the input of the speed change mechanism 41 and the engine output are integrally engaged. Therefore, power is transmitted to the engine output and the input of the speed change mechanism 41 via the lockup clutch 45.
When the lockup clutch 45 is released (when the L / C up is released (non-operation)), power is transmitted between the input of the speed change mechanism 41 and the engine output via the torque converter 40.

Each solenoid such as the shift solenoid for shifting of the control valve section 42 and the lock-up solenoid 49 when the lock-up mechanism is provided.
Is controlled by the control unit 16, and the automatic transmission 12 determines the selected shift speed by the combination of ON and OFF of the shift solenoid.
Similarly, due to, for example, duty control of the lockup solenoid 49 in the control valve unit 42, a converter state in which input / output elements are not directly connected or a lockup state in which input / output elements are directly connected is set.

The control unit 16 detects a signal from a throttle opening sensor (throttle valve sensor) 61 for detecting a throttle opening TVO of the engine 11, a signal from an engine rotation sensor 62 for detecting engine rotation, and a turbine rotation. A signal from the sensor 65, a signal from an output shaft rotation sensor 66 that detects the rotation of the transmission output shaft, and the like are input. The rotation speed information of the transmission output shaft 43 is used as vehicle speed Vsp information. The control unit 16 includes a microcomputer. Here, based on the input information, arithmetic processing is performed in accordance with a shift control program stored in advance in its storage circuit, and the control program for lockup control and other control programs when applicable, and solenoid control signals are calculated. Then, necessary control such as shift control and lockup control is executed.

When the lock-up control is included, the control content may be known. For example, the control unit 16 uses the table data corresponding to the lockup diagram as shown in FIG. 5 in a lookup system to determine whether the vehicle is in the lockup region or the converter region based on the throttle opening TVO and the vehicle speed Vsp. It is determined whether or not there is, a control command (duty command value) is determined, and in accordance therewith, control is performed via the duty control of the lockup solenoid 49 so that the torque converter 40 is locked up or put into a converter state. . In this case, the lockup of the torque converter 40 achieves this by setting the drive duty of the solenoid 49 to 95%, for example, and the converter state achieves this by setting the drive duty to 5%. Good.

The engine control unit 15 and A
Such a control unit 16 for / T can be connected to allow intercommunication. In FIG. 1, the intake passage 20 of the engine 11 has a throttle valve 21 as shown in FIG. 4, and in the present embodiment, a passage 22 that bypasses upstream and downstream of the throttle valve 21 in the intake passage 20. In addition, an electronically controllable AAC valve 23 is provided.

Here, the throttle valve 21 may be mechanically interlocked with an alsel pedal (not shown) operated by a driver to adjust its opening. In this case, the engine 11 is linked to the Alsel pedal.
A device (first device) for increasing / decreasing the torque of is configured to include the throttle valve 21. AAC valve 23
Is a device that controls the amount of auxiliary air by controlling the engine control unit 11. The present device can be used for idle speed control of the engine 11 and for all or part of the engine torque variable control according to the present embodiment as described later. The output torque control of the engine 11 may be fuel supply control (including fuel cut control), ignition timing control, or the like, or combination control thereof, but in the following, the intake air amount control will be used.

As an example of the torque increasing device for the engine 11, the system of the engine control system relating to the AAC valve 23 shown in FIG. 1 or FIG. 4 uses the electric signal from the engine control unit 15 (ECCSC / U) for the intake air as the AAC. The control is performed by using the valve 22, and the control method and the contents when the AAC valve 23 functions as an idle control valve to perform normal idle speed control may be known. Further, the valve control itself may be either valve opening control or duty ratio control which is adopted in the electronically controlled engine, but here, it is assumed to be performed by duty ratio control.

If the AAC valve 23 is driven by duty control, the above control can be summarized as follows (for example, Nissan maintenance manual F00671).
6, for R33, issued 1993/8).

The AAC valve 23 is, for example, a proportional solenoid type valve which is directly actuated by the output signal of the control unit 15, and the halve is driven ON-OFF at a frequency of about 160 Hz. Air volume shall be increased. Therefore, the ECCS control unit 15 changes this ON time,
It is possible to control the amount of auxiliary air, and thus idle rotation control.

As a concrete control method, for the idle rotation speed feedback (F / B) control target value, the cooling water temperature, the elapsed time after starting, the battery voltage,
Determined by input information such as power steering (power steering) switch, air conditioner switch, gear position of A / T car, etc., and if the target value deviates by more than a predetermined value (for example, 25 rpm or more), F / B control approaches the target value. I do. However, the conditions for performing the F / B control are the following conditions, and the control area is set so that the F / B control is stopped if any one of them is canceled. Condition: Throttle sensor idle judgment ON condition: Vehicle speed 8km / h or less, or neutral switch ON

Here, the throttle sensor 61 has a throttle valve switch (idle switch (SW)), and its ON / OFF is also detected by the throttle valve position signal (throttle opening information) given to the engine control unit 15. Can be included.

Although the auxiliary air control device has been described above, the same applies to the electronically controlled throttle device (electrically controlled throttle). In the control method of the engine 11 according to the present invention, separately from the first device that increases or decreases the engine torque in conjunction with the Arcel pedal,
As a second device, a device for increasing / decreasing the torque based on a signal from the electronic control device is provided for control. In the present embodiment, the second device includes the AAC valve 23 and the engine control unit 15. Composed of.

The engine control unit 15 for electronically controlling the engine 11 includes an input detection circuit, an arithmetic processing circuit, a fuel supply control program and an ignition timing control program executed by the arithmetic processing circuit, and the above AAC.
Idle rotation F / B by controlling auxiliary air amount of valve 23
Various calculations such as a program for control, etc., and a program for engine torque compensation control (variable control) for ensuring anti-stalling (engine stall) at the time of deceleration described later using the AAC valve 23, etc. It can be configured using a microcomputer including a memory circuit that stores programs and the like, and an output circuit that outputs a control signal (driving duty signal) to the AAC valve 23.

In the idle rotation speed F / B control, the control unit 15 operates as described above when idle.
Predetermined required operating parameters such as engine cooling water temperature information, auxiliary equipment load information for air conditioners (water temperature signal, switch valve position signal, vehicle speed signal, neutral signal, engine rotation signal, intake air amount signal, air conditioner signal, power steering signal, etc. Based on the above), it is possible to perform control by sending a drive control signal (idle rotation speed control signal) to the AAC valve 23 so as to adjust the amount of bypass air that bypasses the throttle valve 21 at the time of starting or during warm-up. In this case, the control program (not shown)
Among them, the AAC valve 2 required for the idle rotation control
The duty command value of No. 3 is calculated and determined, and in the control signal output processing step, control is executed so as to output the duty signal according to the duty command value.

Here, on the engine control unit 15 side, the engine rotation speed is used as an input in order to stably secure the stalling resistance even in the engine operating region accompanied by a sudden change in the engine rotation speed. The difference between the generated torque and the load torque is estimated from the ratio, and the torque to be increased or decreased (to be compensated) is calculated from the difference between the target rotation change ratio and the actual rotation change ratio, and the AAC valve 23 is In order to give a duty signal according to the torque to be increased or decreased, the AAC valve 23
Control shall be performed.

In this case, preferably, the control unit 15 controls the rotational speed of the engine 11 when the first device (the device that increases or decreases the torque of the engine 11 in conjunction with the Alcel pedal) is in the minimum output demand state. On the other hand, it has a target value of the speed-time differential value, and based on the difference between the target value of the differential value and the actual value of the differential value, the second value
This can be done by determining the AAC valve duty command value as the torque increase / decrease command value of the device (device that increases / decreases the torque based on the signal from the electronic control device).

Whether or not the above-mentioned minimum output demand state is present can be judged by checking whether or not the driver's expected output value to the engine 11 is minimum, and again, AA
In the case of a vehicle-mounted engine equipped with a C valve, the valve 23 is effectively used in this way to realize the present control. Further, in this case, in the storage circuit of the control unit 16, in addition to the program for calculating the duty command value of the AAC valve 23 by the above-described method, the target value of the engine rotation speed time differential value is previously stored in the engine. For example, it can be stored in the map data as a function of the rotation speed. The target value can be set sequentially based on the read engine rotation speed by map search at the corresponding time.

Preferably also the control unit 1
When the engine to be controlled is the engine 11 to which the torque converter and the lockup device are loaded, 5 uses the control method only when the lockup is not engaged. In this case, the engine control unit 15 takes in and uses information on the lockup (L / U) control performed on the side of the A / T control unit 16 described with reference to FIGS. 2 to 4. be able to.

Further, the above points will be specifically described with reference to FIG. 6 and subsequent figures. FIG. 6 shows the basic relationship between the internal combustion engine rotation speed and the vehicle speed during deceleration, FIGS. 7 and 8 show data of an example of the time transition of the internal combustion engine rotation speed and other quantities particularly during sudden braking, and FIG. 9 shows the load torque. Examples of models used to explain the calculation are shown respectively, and FIG. 10 is a specific example of the control program, which will be described below in this order.
First, the following matters and contents show a basic concept of control according to the present invention.

(1) Basic Concept FIG. 6 shows the result of consideration of the relationship between the engine speed during deceleration and the vehicle speed Vsp when the engine (internal combustion engine) undergoes a rapid change in the rotational speed. . When the vehicle speed Vsp changes as shown during braking, as shown in the figure and as described below, the rate of decrease of the engine speed (actual engine speed) is affected by the load torque. The change is as shown by the dotted line.

Generally, the setting of the operating conditions such as the ignition advance angle and the fuel amount of the internal combustion engine is optimized by a steady-state test. However, when the internal combustion engine is accompanied by a sudden change in rotation speed,
Due to factors such as a delay in the change in intake air amount, the operation setting conditions for obtaining optimum combustion differ from those in the steady state. In particular,
As will be described later, a sudden decrease in the rotation speed of the internal combustion engine, such as during a sudden braking on a low μ road, does not result in an optimum operating condition rotation speed change when a steady control constant is used. Getting worse.

Under such a condition, a control constant map may be provided for each change in rotational speed, and a method of using the map may be considered. However, an internal combustion engine for a vehicle includes an oil pump for power steering, a compressor for an air conditioner, an automatic transmission. Since the load torque is applied from other requirements such as the oil pump described above regardless of the internal combustion engine, it is not sufficient to simply have a control constant map for each change in rotational speed.

Thus, the rate of decrease of the internal combustion engine rotation speed is
Due to the influence of the load torque at that time, it becomes as shown by the dotted line in FIG. When following this control, even in such a case, the torque increase amount required based on the deviation from the target value (solid line) in order to compensate for this load torque so as to ensure stable stalling resistance. To calculate. If the generated torque of the internal combustion engine can be adjusted according to the load and the generated torque corresponding to all the loads of the internal combustion engine can be given, it is effective for improving the engine stalling performance.

Further, as also shown in FIG. 6, the target value at the time of sudden braking shifts from the normal value (see the alternate long and short dash line).
Therefore, in this case, the torque to be compensated (to be increased / decreased) is calculated according to the target value, and the torque generated by the internal combustion engine is adjusted so as to obtain it.

(2) Time Transition of Internal Combustion Engine Rotational Speed During Braking FIG. 7 and FIG. 8 show specific examples of time transitions of various quantities including the rotational speed of the internal combustion engine during braking. These are examples of sudden braking as well as cases of vehicles equipped with an automatic transmission equipped with a lockup mechanism, in which a sudden braking is applied from the coast state, and the lockup is released by the determination of the sudden braking. It is time data.

As shown in the figure, here, the idle SW is used.
And the brake SW are turned on in this order based on the braking operation of the driver and at the timings shown in FIGS. 7 and 8, and the brake pressure changes as shown in FIG. On the other hand, the electric command for unlocking the lock-up is given when the lock-up duty (lock-up solenoid drive duty) changes from 95% to 5%, as mentioned above (FIG. 7). After this, the release pressure of the lockup clutch rises, the pressure difference from the apply pressure gradually decreases, and the hydraulic pressure intersects (= transmission torque capacity is 0) (FIG. 8). Thus
At the timing shown in the figure after the lock-up release command, the pressure is switched by the lock-up mechanism,
It will shift to the converter state.

Here, regarding the lock-up opening delay,
The following is a description of the schematic configuration of FIG. When switching the lock-up clutch 45 from the engaged state to the disengaged state, at the time of lock-up, a control command to the lock-up control valve 48 is issued to the release oil passage connected to the oil cooler → rear lubrication → drain system as described above. Based on this, a line pressure oil path → lock-up control oil path → release pressure oil path → apply pressure oil path → oil cooler → rear lubrication → drain is formed. As a result, pressure is applied to this release oil passage, which had little pressure until then.

At this time, in order to increase the pressure, the flow rate due to the deformation of the parts due to the elasticity or the like is required accordingly. Therefore, in order to achieve the quick release of the lockup clutch 45, the flow rate per unit time needs to be increased by that much, but the theoretical pump discharge rate (volume per hour) is the engine rotation speed that is the drive source of the pump 50. Since it is given by the product of the speed (the number of rotations per hour) and the specific discharge amount (volume per one rotation) of the pump 50, the release flow rate is naturally limited. Therefore, the engagement torque capacity decreases with time. Thus, the engagement torque capacity gradually decreases, and the lockup clutch 43
Is released. From FIGS. 7 and 8, it can be seen that the pressure switching in this process, and thus the lockup release with the opening delay, progresses.

Therefore, FIG. 9 is given as a model for calculating the load torque in the above case. In the figure, examples of the load on the engine (internal combustion engine) include an auxiliary device load such as an air conditioner, a transfer torque load of a lockup clutch, a transfer torque load of a torque converter, and an oil pump load of an automatic transmission. Particularly, the drag torque based on the opening delay of the lockup becomes a serious load during a sudden braking (during a sudden braking on a low μ road where the tire (driving wheel tire) is likely to be locked early). In the case of this model, the torque to be compensated according to the present control is determined from the following viewpoints, and the torque generated by the internal combustion engine is variably controlled.

(3) Concept of calculation of torque to be compensated In FIG. 9, the following equation holds.

[0054]

## EQU1 ## Ip × (dω / dt) + {Te + Tf + Th + Tp + Tc + Tt} = 0 (1) However, Ip: Inertial performance ratio of the internal combustion engine (output shaft converted inertial performance ratio) ω: Rotation speed of the internal combustion engine (per unit time) Te: torque generated by the internal combustion engine (output torque) Tf: friction torque of the internal combustion engine Th: internal combustion engine accessory load torque (auxiliary drive torque) Tp: automatic transmission oil pump load torque (oil pump drive) Torque) Tc: Transfer torque of lock-up clutch (drag torque) Tt: Input transfer torque of torque converter (in the figure, the output shaft is judged as input or output by the symbol value)

From this equation, the rotation change of the internal combustion engine (= dω / d) is caused by the difference between the torque generated by the internal combustion engine and the load torque.
It can be seen that t) is determined. In other words, the target value of the rotation change (= dω / dt) of the internal combustion engine (therefore,
The target value of the internal combustion engine rotation speed time differential value) is set for each rotation speed of the internal combustion engine, and the generated torque of the internal combustion engine is adjusted to reach this set value, whereby the finally settled internal combustion engine rotation speed can be controlled. .

On the contrary, while estimating the difference between the generated torque and the load torque at that time from the difference between the target value and the actual value of the rotation change ratio of the internal combustion engine, the generated torque corresponding to the torque required for compensation according to the load is calculated. This method, which enables adjustment, and therefore proper adjustment without excess or deficiency, is basically a method that can generate torque corresponding to all loads at that time of the internal combustion engine when avoiding engine stall, as seen in the above model. And
When applicable, even when the above-mentioned drag torque of lock-up occurs, it is possible to properly compensate for all the load torque applied to the engine, including the torque increase amount against it, which is highly compatible. Exert its abilities.

FIG. 10 shows an example of a control program that embodies the above control method. This program example is for the engine 11 (FIGS. 1 to 4) that transmits the output torque via the torque converter 40 with the lockup clutch 43, and relates to the ACC valve duty command value calculation for the generated torque variable control for the engine 11. It is an example of a program flow chart.

It is assumed here that this program is executed on the engine control unit 15 (FIGS. 1 and 4) side. Lockup (L /
Regarding the determination of whether or not U) is performed, the A / T control unit 1 is determined based on the lockup diagram (FIG. 5).
6 and under the control of the A / T control unit 16, control for lock-up engagement is performed when lock-up should be performed (this may be the same as the known conventional control. , As already mentioned). However, when combined with lockup control, the A / T control unit 16 side is shown in FIG.
It is also possible to execute the arithmetic processing according to the routine shown in and apply the arithmetic result to the control of the ACC valve 23 on the engine control unit 15 side. Looking at the flow of FIG. 10, here, the determination after the lockup state (lockup during deceleration) is shown. In this routine, for example, this calculation is performed every 10 ms. The process consists of steps 101-109 shown in the figure.

(1) In this program example, first, it is determined by an idle switch or the like whether or not the output expected value of the driver (driver) to the internal combustion engine (engine 11) is minimized. For example, idle SW
It is checked whether (valve switch of the throttle valve 61) is ON (step 101). Next, it is checked whether the L / U release command is output (step 102). The check process for this is the A / T control unit 1
This can be done by fetching the lockup control information from 6 and monitoring it.

As a result of the above judgment, when the expected output value of the driver to the internal combustion engine is minimum, it is regarded as the coast state, and in the coast state and the lockup non-fastened state, that is, the L / U release signal. Only when it is determined as a result of the check in step 102 as to whether or not was output, the control proceeds to the next step 103 and subsequent steps.
In addition, in the cases other than the above, the processes of steps 103 to 109 are passed.

In this example, step 103 to step 10
Reference numeral 9 indicates reading of the internal combustion engine rotational speed in the current loop, setting of the target value of the internal combustion engine rotational speed time differential value, calculation of the actual value of the internal combustion engine rotational speed time differential value, calculation of the difference (deviation) between them, A that is a function of the difference between the two and the rotation speed
It consists of calculation of the duty command value addition of the AC valve 23 and output processing. (2) First, the current internal combustion engine speed (ω0) is read based on the input signal from the rotation sensor 62, and based on this, the target ( The value of dω / dt) (the target value of the internal combustion engine rotation speed time differential value) is read from the map. Here, the differential value (dω / dt) of the target internal combustion engine rotational speed, which is a function of the internal combustion engine rotational speed, is set in advance so as to approach the value 0 as the rotational speed becomes smaller.

(3) Next, the previous internal combustion engine rotational speed (ω1) and the elapsed time t from the previous reading are read, and the differential value of the current internal combustion engine rotational speed is calculated by (ω1-ω0) / t. . (4) Next, the difference between the target value obtained in step 104 and the actual value in step 106 for the internal combustion engine rotational speed time differential value {target (dω / dt) -current (dω / d)
t)} is calculated.

(5) Next, the internal combustion engine rotation speed (ω)
And the above {target (dω / dt) -current (dω / d
The electric signal value to be commanded is determined from two variables such as t)}. The duty value in this case can be calculated by using a characteristic map as shown in FIG. 11, for example. The map data example in the same figure is for when the duty is high and is adapted to the ACC valve control system for auxiliary air amount control in which the air amount is set large. According to this, for example, even if the target value and the actual value shown on the vertical axis have the same degree of deviation, the rotation speed (rpm) shown on the horizontal axis
Depending on the magnitude of, the calculated duty value is obtained as a smaller value (larger value) as the rotational speed is higher (smaller) than when the rotational speed is small (larger). In this program example, necessary arithmetic processing is performed using a map as shown in FIG. (6) Then, the command value is commanded while the lockup release command is issued.

(7) This routine (step 101,
By repeating steps 102, 103 to 109), it is possible to gradually approach the internal combustion engine rotational speed target value during idling. The time of the differential value 0 corresponds to the idling internal combustion engine rotation speed.

By the control processing as described above, it is possible to achieve the control method according to the method described with reference to the model of FIG. 9 and the equation 1. At the time of deceleration during L / U engagement, the amount of increase when increasing the engine output in order to avoid engine stall is also appropriately calculated, and the torque increase equivalent value with respect to the drag torque of L / U can be calculated accurately. This can be reflected in the torque variable control via the auxiliary air amount control by the ACC valve 23, and appropriate compensation can be realized so as to give the generated torque corresponding to the load, and the stalling performance is stable and reliable. Becomes This is effective for engine stall avoidance control when braking is applied from coast lockup.

The following points are also effective. That is, in the present embodiment, the control described above is applied only when the lockup is not engaged. this is,
It is based on the consideration of the following. If the internal combustion engine rotation speed is controlled in the lockup engagement state by the above method, there is no slippage of the torque converter when the lockup engagement is in effect, so this control controls the vehicle speed. If the ability of the device that increases or decreases the torque based on the signal from the electronic control device as the second device described above is large, it means that the driver cannot stop the vehicle. A vehicle acceleration torque is generated against the driver's will, and this is directly reflected in the vehicle speed, which deteriorates drivability for the driver.
On the other hand, according to this example, the capability of the second device to be applied is not affected, and such a situation can be avoided.

Even if the engine is not locked up, if the internal combustion engine rotational speed increases more than necessary, the operability deteriorates. However, in the embodiment program, the required internal combustion engine generated torque is constantly monitored. As a result, it does not become empty or depressed, so even in this respect,
It is possible to improve engine stall resistance while ensuring drivability better than before.

Further, since the engine stall on the low μ road can be avoided during the coast, the lockup can be fastened during the coast, and the rotation increase of the internal combustion engine at the time of re-pedaling can be performed as compared with when the coast lockup is not performed. Since it can be suppressed, the effect of improving fuel efficiency can be maximized, and the number of times lock-up is turned on and off can be reduced, so that the durability of lock-up facing can be improved.

Next, another embodiment (second embodiment) of the present invention.
This will be described with reference to FIGS. 12 and 13. Like the above-described embodiment (first embodiment), this embodiment is different from the device that increases or decreases the torque of the internal combustion engine in conjunction with the accelerator pedal operated by the vehicle driver, based on a signal from the electronic control device. And a torque converter that amplifies the torque of the internal combustion engine and transmits the amplified torque to the speed change mechanism,
In a vehicle internal combustion engine that includes a lockup clutch that is arranged in parallel with a torque converter that is controlled to be engaged or disengaged by an electronic control device, a device that increases or decreases the torque of the internal combustion engine in conjunction with an accelerator pedal is a minimum output required state. , The target value of the speed-time differential value for the rotational speed of the internal combustion engine, the torque based on the signal from the electronic control unit based on the difference between the target value of the differential value and the actual value of the differential value. The torque increase / decrease command value of the device to be increased / decreased is determined, but in the present embodiment, a sudden braking detection means is further provided, and it is determined that the braking is determined to be a sudden braking or not. The present invention relates to a control method in which different torque increase / decrease command values are used.

FIG. 12 and FIG. 13 are examples of a program flow chart showing the main part of the control according to this embodiment.
In this embodiment, the system configuration and the basic concept are the same as those in the above embodiment, and are the same as the configurations and contents shown in FIGS. 1 to 5 and 6 to 9. Also, in the control program, this program example is shown in FIG.
3 includes steps 201 to 212, and, for example, steps 201 and 208 to 212 correspond to the processing of steps 103 to 109 in the program of FIG. 10 and are basically the same. Good. Less than,
The main part of the contents of the control of this embodiment will be described.

(1) In FIG. 12, first, in the present program example, the current internal combustion engine rotation speed (ω0) is read (step 201) with the same processing contents as in step 103 of FIG. According to the same processing content as in step 101 of 10, when the output expected value of the driver to the internal combustion engine is minimized by the idle SW or the like,
It is regarded as the coast state (step 202), and in this state, control proceeds to the next step 203 and the subsequent steps. In this program example, as shown in FIG.
4, 205, 206 and 207 are provided, and the target value map of the internal combustion engine rotation speed time differential value has a map for sudden braking and a map for normal that is not for sudden braking, and these are used properly. Regarding the sudden braking judgment in step 203, for example, the brake switch is turned on.
Also, it can be performed by detecting the longitudinal acceleration information, or by detecting the rate of increase in brake fluid pressure. In this case, this control system is configured to include these vehicle brake system elements.

(2) When the lock-up clutch is not in the engaged state because the brake is not applied suddenly, the same control as in the first embodiment is performed (step 203 → 204 → 205 → 2).
08 → 209 → 210 → 211 → 212). in this case,
The target value of the internal combustion engine rotational speed time differential value obtained by the search on the normal map is set, and the torque generated by the internal combustion engine is adjusted so that the actual value becomes the set target value. Will be controlled to avoid engine stalls. On the other hand, when it is determined that the lockup clutch is not in the engaged state and is in a sudden brake, the lockup clutch is released (lockup non-engagement command output) (step 20).
3 → 206).

(3) Then, at this time, the target (dω / dt) value for sudden braking set for each internal combustion engine rotation speed (ω) is read (step 207).
Thus, the target value for sudden braking is set as the target value of the internal combustion engine rotational speed time differential value each time this step 207 is executed, and the process proceeds to step 208 and subsequent steps, and step 2
The control is executed in the procedure of 08 → 209 → 210 → 211 → 212 (FIG. 13) (the same procedure and content as described in the first embodiment).

(4) That is, the current (dω / dt) is calculated. (5) {target (dω / dt) -current (dω / d
t)} is calculated. (6) Internal combustion engine rotation speed (ω) and {target (dω / d
The electric signal value to be commanded is determined from the two variables of (t) -current (dω / dt)}. (7) The command value is commanded while the lockup release command is issued. (8) This routine (steps 201 to 203, 20
6 to 212) is repeated.

As described above, the engine control unit which performs variable torque control to prevent engine stall has different command values to be applied depending on whether it is determined to be a sudden braking or not. The torque that should be increased or decreased is calculated from the difference between the target rotational speed time differential value and the actual rotational speed time differential value, and the second device is controlled according to the increased or decreased torque. In the mode of executing the control so as to give a signal,
It can be implemented.

Also in this embodiment, the same operational effects as those of the above-mentioned embodiment can be obtained. At the time of a sudden braking, not only the drag torque increment due to the lock-up opening delay but also the generated torque corresponding to all the loads of the internal combustion engine can be given, and the stalling performance can be made more stable and reliable. At the time of sudden braking during L / C engagement, the amount of increase when increasing the engine output to avoid engine stall can be calculated appropriately.
In other words, if this increase is small, engine stall cannot be avoided, and if it is too large, it will be against the driver's intention to operate the brakes. Certainly avoidable.

Further, in this embodiment, in addition to the one according to the first embodiment, as described above, a command value that is different from the command value that is used when the brake is not applied can be used. Can also be realized. In an emergency such as a sudden braking, the desired braking can be obtained, and basic requirements such as engine stall do not matter.As a result of prioritizing them, drivability such as changes in the rotation speed of the internal combustion engine differ from normal It can be said that the problem of No. can be ignored, and since the change in rotation speed is rapid, it is better to set the control delay etc. in advance, which is easily answered. Become. In addition, drivability does not deteriorate during normal driving other than sudden braking.

The present invention is not limited to the above embodiments, modifications and the like. For example, as a second device that controls the torque of the internal combustion engine based on a signal from an electronic control device, which is different from the device that increases or decreases the torque of the internal combustion engine in conjunction with the accelerator pedal, the intake air amount control is used. However, it is not limited to this. It is applicable as long as the torque generated by the internal combustion engine can be adjusted by external control. Further, even when the intake air amount control is used, it is not necessary to use the auxiliary air control, and even when the auxiliary air control is used, it is not necessary to use only the auxiliary air control.

Further, although the embodiment has been described mainly for the purpose of calculating the increase in the lockup drag torque, the present invention compensates for all load torques applied to the internal combustion engine. Is possible, and therefore
It is not limited to the control of the internal combustion engine of the vehicle having the torque converter and the lockup device. However, in any of the respective embodiments, when the lockup device is provided, it is effective to apply the control of the second device when the lockup clutch is not engaged as described in the first embodiment. In addition, in any of the examples,
As described in the first embodiment, this also suppresses the increase in rotation of the internal combustion engine at the time of re-depressing, and maximizes the fuel consumption improving effect. In addition to this, lockup ON,
The number of OFF times can be reduced and the durability of lock-up facing can be improved, which is advantageous as control of an internal combustion engine of a vehicle having a torque converter and a lock-up device.

[0080]

According to the present invention, in controlling an internal combustion engine for a vehicle, it is possible to compensate various load torques applied to the internal combustion engine at a corresponding control time point in order to avoid engine stall, and the load torque can be compensated. It is possible to adjust the torque generated by the internal combustion engine, and not only that, even if there is a torque increment due to the lock-up opening delay during sudden braking,
Including this, the generated torque that appropriately corresponds to the load of the internal combustion engine is given, the engine stall performance can be made stable and reliable, and the engine stall resistance can be stably ensured. In particular, the torque to be varied as described in claim 2 is calculated from the difference between the target rotation change rate and the actual change rate and the rotation speed of the internal combustion engine, so that the engine stall resistance is more stable. It is possible to secure it.

According to the third aspect of the invention, the torque of the internal combustion engine is increased or decreased in conjunction with the accelerator pedal.
Device, a second device for controlling the torque of the internal combustion engine on the basis of a signal from the electronic control device, and a means for determining a torque variable command value of the second device. A control device that realizes the above can be obtained.

Further, in the case where the torque converter and the lock-up clutch are provided as described in claim 4, when the control by the second device is applied when the lock-up clutch is not engaged, in addition to the above, the torque is temporarily assumed. There is no slippage of the converter.If control is performed while lockup is engaged, deterioration of drivability due to generation of vehicle acceleration torque contrary to the driver's intention, etc. can be avoided. In addition, it is possible to effectively improve the engine stall resistance while ensuring drivability without causing vacancy or depression. In addition, the engine stall performance is stable and reliable, and the engine stall on low μ roads can be appropriately avoided when coasting, so you can engage the lockup clutch during coasting and compare when not coasting up. Then, the increase in the rotation of the internal combustion engine is suppressed when the pedal is depressed again, so that the fuel consumption improving effect can be maximized, and its original function as a lockup device is also made more effective. Not only is it possible to reduce the number of times lock-up is turned on and off, it is possible to improve the durability of lock-up devices such as lock-up facings, especially for vehicles that are loaded with a torque converter and lock-up device. It can be effective in controlling the internal combustion engine.

In addition to the above, according to the fifth aspect of the present invention, in addition to the above, a command value different from that when not being suddenly braked can be used for sudden braking, and such control can be performed. Since finer control is possible and the change in rotation speed is rapid, it is possible to easily use different values such as setting a control delay in advance, and to improve drivability during normal operation other than sudden braking. It becomes possible to avoid the deterioration.

Further, as described in claim 6 or claim 7, as for the torque control by the second device, the fuel supply control is performed by the intake air amount control, in place of or in addition to the intake air amount control. The control according to any one of at least one of ignition timing control, and in that case, the intake air amount control is auxiliary air control, or at least intake air amount including this. As an aspect of control, the present invention can be implemented, and the above can be realized as well.

[Brief description of drawings]

FIG. 1 is a diagram showing an embodiment of the present invention.

FIG. 2 is an explanatory diagram of a control system in the same example.

FIG. 3 is an explanatory diagram of an example of a lockup mechanism of an automatic transmission, a hydraulic control device, and the like that can be applied to the control system.

FIG. 4 is a diagram showing an example of an internal combustion engine auxiliary air control system that can also be applied.

FIG. 5 is a diagram illustrating lockup lines applied in lockup control.

FIG. 6 is a diagram showing an example of a relationship between an internal combustion engine rotation speed and a vehicle speed during deceleration.

FIG. 7 is a diagram of data representing an example of a time transition of various amounts such as an internal combustion engine rotation speed when braking is applied from coast lockup.

FIG. 8 is a diagram of data similarly showing a time transition example of other quantities.

FIG. 9 is an explanatory diagram of a model of the output, load, and speed of the internal combustion engine.

FIG. 10 is a flowchart of an example of a control program executed by the control unit.

FIG. 11 is a diagram showing an example of a duty value calculation map applied by the program.

FIG. 12 shows an example of a control program of a main part of control according to another embodiment of the present invention, and is a flowchart showing a part thereof.

FIG. 13 is a flowchart showing another part of the same control program.

[Explanation of symbols]

1L, 1R front wheels 2L, 2R rear wheels 11 engine 12 automatic transmission 13 differential gear 15 engine control unit (ECCSC /
U) 16 A / T control unit (ATC / U) 20 intake passage 21 throttle valve 22 bypass passage 23 AAC valve 40 torque converter 41 transmission mechanism 42 control valve portion 43 output shaft 45 lockup clutch 46 torque converter cover 47 turbine (turbine) Runner) 48 Lockup control valve (Lockup control valve) 49 Lockup solenoid 50 Oil pump 51 Regulator valve 61 Throttle opening sensor (Throttle valve switch) 62 Engine rotation sensor 65 Turbine rotation sensor 66 Output shaft rotation sensor

─────────────────────────────────────────────────── ─── Continuation of front page (51) Int.Cl. ⁷ Identification code FI F02D 45/00 362 F02D 45/00 362J F02P 5/15 F02P 5/15 C

Claims (7)

(57) [Claims] 1. A second device for controlling torque of an internal combustion engine based on a signal from an electronic control device, separately from a first device for increasing or decreasing the torque of the internal combustion engine in conjunction with an accelerator pedal operated by a driver of a vehicle. In an internal combustion engine for a vehicle equipped with the above device, the rotational speed of the internal combustion engine is input, and the difference between the target rotational change rate estimated based on the difference between the internal combustion engine generated torque and the load torque is calculated from the actual rotational change rate. A method for controlling an internal combustion engine for a vehicle, comprising: calculating a torque to be varied, and controlling the generated torque of the internal combustion engine by the second device according to the calculated torque. 2. The torque to be varied is set to the target
The difference between the rotational change rate of the internal combustion engine and the actual change rate,
It calculates from the rotation speed of the seki.
A method for controlling an internal combustion engine for a vehicle according to the above. 3. A first device for increasing or decreasing the torque of an internal combustion engine in association with an accelerator pedal operated by a vehicle driver,
A control device for an internal combustion engine for a vehicle, comprising: a second device for controlling a torque of the internal combustion engine based on a signal from an electronic control device, the rotation of the internal combustion engine when the first device is in a minimum output request state. For the speed, find the target value of the speed time derivative,
Based on the difference between the target value of the differential value and the actual value of the differential value,
A control device for an internal combustion engine for a vehicle, comprising means for determining a variable torque command value of the second device. Wherein said vehicle comprises a torque converter for transmitting the transmission mechanism amplifies the torque of the internal combustion engine, the fastening by the electronic control unit, and a lock-up clutch disposed in parallel with the torque converter to be controlled non-engagement The control device for a vehicle internal combustion engine according to claim 1, wherein the control method is used when the lockup clutch is not engaged. A detection unit 5. A hard braking, at a time not during sudden braking and sudden braking, claims, characterized in that to apply a value different from the variable torque command value
The control device for an internal combustion engine for a vehicle according to claim 3 or claim 4 . 6. A torque control by the second device, or by the intake air amount control, alternatives to the inhalation air amount control,
Or together with this, fuel supply control, Kano according to at least any one of the control of the ignition timing control, according to claim 3, characterized in that any aspect, wherein
The control device for an internal combustion engine for a vehicle according to claim 4 or claim 5 . 7. intake air amount control according to claim 6, wherein the control apparatus for an internal combustion engine for a vehicle, wherein the auxiliary or air is controlled, or the intake air amount control including at least the same.