EP0903257A2

EP0903257A2 - Torque controlling apparatus for vehicle-mounted internal combustion engine

Info

Publication number: EP0903257A2
Application number: EP98117674A
Authority: EP
Inventors: Yuichiro Kato
Original assignee: Toyota Motor Corp
Current assignee: Toyota Motor Corp
Priority date: 1997-09-18
Filing date: 1998-09-17
Publication date: 1999-03-24
Anticipated expiration: 2018-09-17
Also published as: JPH1193733A; DE69803641D1; DE69803641T2; EP0903257B1; EP0903257A3; JP3752797B2

Abstract

When an accelerator pedal (25) is suddenly stamped on, the amount of fuel injected into an engine (12) increases sharply, and the rotating force of a crankshaft (14) is increased, so that when the rotation is transmitted from the shaft (14) to an automatic transmission (23), a force which tends to twist an automobile (11) in the rotating direction of the shaft (14) is applied to the automobile (11). Consequently, the automobile (11) vibrate in the back-and-forth direction, and variations occur in the engine speed. The variations in the engine speed and the vibrations of the automobile (11) are suppressed by executing fuel-injection-amount correction corresponding to the variations in the engine speed with a predetermined phase difference and an incremental pattern with respect to the variations. As the phase difference () is thus provided, the output torque of the engine (11) which changes by lagging behind the fuel-injection-amount correction can be suitably regulated so as to suppress the variations in the engine speed.

Description

BACKGROUND OF INVENTION

The present invention relates to a torque controlling apparatus for a vehicle-mounted internal combustion engine, and more particularly to an apparatus for performing torque control so as to control vibrations occurring during a sudden acceleration of a vehicle.
In general, in a diesel engine for an automobile, a piston is provided in its cylinder block in such a manner as to be capable of reciprocating, and the piston is connected to a crankshaft (output shaft) of the diesel engine through a connecting rod. The reciprocating movement of the piston is converted to the rotation of the crankshaft by the connecting rod. In addition, the cylinder block is provided with a cylinder head, and a combustion chamber is provided between the cylinder head and the head of the piston. The cylinder head is further provided with an intake passage and an exhaust passage which communicate with the combustion chamber and a fuel injection valve for injecting fuel toward the interior of the combustion chamber.
In the diesel engine, in its intake stroke air is sucked into the combustion chamber through the intake passage, and in its subsequent compression stroke the air in the combustion chamber is compressed by the movement of the piston. Then, in a final stage of the compression stroke mist-like fuel injected into the combustion chamber by the fuel injection valve is self-ignited by the compression heat of the air and bums. As a result of the burning of the fuel, the piston moves in the opposite direction to the aforementioned direction, and the diesel engine obtains a driving force and shifts to the combustion stroke. Subsequently, in the exhaust stroke of the diesel engine, the exhaust gases in the combustion chamber are exhausted to the outside through an exhaust passage by the movement of the piston.
In such a diesel engine, the amount of fuel which is injected and supplied into the combustion chamber is adjusted on the basis of the pressed amount of an accelerator pedal provided in the vehicle compartment, and an engine output is regulated by this adjustment of the amount of fuel injection. In addition, the crankshaft of the diesel engine is connected to the wheels of the automobile through a transmission and the like. During the operation of the internal combustion engine, the rotation of the crankshaft is transmitted to the wheels through the transmission, and as the wheels rotate, the automobile travels.
At the time of such as an acceleration of the vehicle, the driver abruptly stamps on the accelerator pedal, so that the amount of fuel injected and supplied into the combustion chamber increases rapidly, and the output torque of the diesel engine increases sharply. If the output torque of the diesel engine thus increases sharply, the rotating force of the crankshaft is increased, so that when the rotation is transmitted from the crankshaft to the transmission, a strong force which tends to twist the automobile to the rotating direction of the crankshaft is applied to the automobile. Then, when the strong force in the twisting direction is applied to the automobile, vibrations acting in the back-and-forth direction occur in the automobile, and the comfort of riding in the automobile deteriorates due to the vibrations.
Accordingly, in order to suppress the aforementioned vibrations occurring during a sudden increase in the amount of fuel injected during such as an acceleration of the automobile, apparatuses have been proposed for correcting the amount of fuel injection in accordance with the vibrations. As an example of such an apparatus, a torque controlling apparatus disclosed in Unexamined Japanese Patent Application No. Hei. 60-26142 is known.
In the apparatus disclosed in that publication, the vibration during an acceleration of the automobile is detected as the variation in the engine speed of the internal combustion engine, and the amount of fuel injection is corrected in accordance with the variation in the revolution, thereby suppressing the vibrations. Here, the control of the amount of fuel injection for suppressing the vibrations by the above-described apparatus is shown in the time chart in Fig. 9. As is apparent from this time chart, when the variation in the engine speed occurs in the internal combustion engine on the basis of the vibrations during an acceleration of the automobile, the amount of fuel injection is corrected by being increased during the drop in the engine speed in the variation in the engine speed of the internal combustion engine. By correcting the amount of fuel injection in this manner, an attempt is made to suppress the vibrations during the acceleration of the automobile.
Thus, with the apparatus disclosed in the above-described publication, although an attempt is made to suppress the vibrations during the acceleration of the automobile by correcting the amount of fuel injection, it takes time until the correction of the amount of fuel injection is reflected on the suppression of the vibrations. This is due to the fact that the output torque of the internal combustion engine does not change immediately after the increase or decrease of the amount of fuel injection, but changes after the lapse of the period of fuel combustion and the period of movement of the piston after the increase or decrease in the amount of fuel injection. Accordingly, even if the amount of fuel injection is corrected by being increased during the drop in the number of revolutions or corrected by being decreased during the rise in the number of revolutions in engine speed fluctuations, the vibrations during the acceleration of the automobile cannot be suppressed suitably.
It should be noted that the above-described vibrations accompanying the sudden acceleration of the vehicle also generally occur in a similar manner with the vehicle with a gasoline engine mounted.

SUMMARY OF INVENTION

The present invention has been devised in view of the above-described circumstances, and its object is to provide a torque controlling apparatus for a vehicle-mounted internal combustion engine which is capable of suitably suppressing the vibrations occurring at the time of commanding a sudden acceleration of the vehicle.
To attain the above object, there is provided a torque controlling apparatus for a vehicle-mounted internal combustion engine, comprising: acceleration and deceleration commanding means operative externaly; suddenly-accelerating-operation detecting means for detecting the presence or absence of a suddenly accelerating operation by the acceleration and deceleration commanding means; and means, when the presence of the suddenly accelerating operation is detected by the suddenly-accelerating-operation detecting means, for correcting the torque of the engine using a predetermined phase difference and a torque varying pattern both which are predetermined with respect to the accelaration condition of the engine in order to suppress vibrations occurring due to a variation in a driving force from the internal combustion engine to the transmission.
Moreover, in the torque controlling apparatus mentioned above, fuel injecting means is further provided, for injecting and supplying fuel in an amount correspondence with operation of the acceleration and deceleration commanding means into the vehicle-mounted internal combustion engine connected to a transmission; the correcting meeans includes fuel-injection-amount correcting means, when the presence of the suddenly accelerating operation is detected by the suddenly-accelerating-operation detecting means, for correcting the amount of fuel injected and supplied with a predetermined phase difference and an incremental pattern with respect to the vibrations in order to suppress vibrations occurring due to a variation in a driving force from the internal combustion engine to the transmission.
In accordance with the above-described arrangement, although it takes time for the fuel-injection-amount correction with the aforementioned predetermined incremental pattern to be reflected on the suppression of the vibrations occurring due to the variation in the driving force from the internal combustion engine to the transmission, since the incremental pattern for increasing the amount of fuel injection with respect to the vibrations is provided with a phase difference, the aforementioned vibrations can be suitably suppressed by the phase difference.
Furthermore, in the fuel injection controlling apparatus for a vehicle-mounted internal combustion engine described above, the apparatus further comprises: shift-position detecting means for detecting a shift position of the transmission, wherein the fuel-injection-amount correcting means makes variable the phase difference in the incremental pattern to be imparted in correspondence with the detected shift position.
In accordance with the above-described arrangement, since the form of occurrence of vibrations occurring due to the variation in the driving force from the internal combustion engine to the transmission changes depending on the shift position of the transmission, by making variable the phase difference in the incremental pattern for increasing the amount of fuel injection with respect to the vibrations in correspondence with the detected shift position, the suppression of vibrations can be suitably attained in whichever shift position the aforementioned vibrations occur.
Still futher, the smaller the reduction ratio of the shift position detected by the shift-position detecting means, the larger the fuel-injection-amount correcting means sets the phase difference in the incremental pattern to be imparted.
Generally, the smaller the reduction gear ratio of the transmission in terms of the shift position, the longer the period of vibration occurring due to the variation in the driving force from the internal combustion engine to the transmission. In accordance with the above-described arrangement, since the smaller the reduction ratio of the transmission in terms of the shift position, the larger the phase difference in the incremental pattern for increasing the amount of fuel injection with respect to the above-described vibrations. Therefore, the suppression of the vibrations can be attained more accurately in whichever position the shift position may be.

BRIEF DESCRIPTION OF DRAWINGS

Fig. 1 is a schematic diagram illustrating an overall automobile to which the present invention is applied;
Fig. 2 is a block diagram illustrating an electric configuration of a torque controlling apparatus in accordance with an embodiment of the present invention;
Fig. 3 is a map to which reference is made when calculating the shift position of an automatic transmission;
Figs. 4A to 4D are time charts illustrating the changes in the amount of fuel injection and the engine speed at each shift position of the automatic transmission;
Figs. 5A to 5C are time charts illustrating the changes in the amount of fuel injection, the engine speed, and an engine speed variation value when the automatic transmission is in the second gear;
Fig. 6 is a flowchart illustrating the procedure for executing fuel injection control in accordance with this embodiment;
Fig. 7 is a flowchart illustrating the procedure for executing fuel injection control in accordance with this embodiment;
Fig. 8 is a flowchart illustrating the procedure for executing fuel injection control in accordance with this embodiment; and
Fig. 9 is a time chart illustrating the conventional control for fuel injection with respect to changes in the engine speed during such as a sudden acceleration.

DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS

Referring now to Figs. 1 to 8, a description will be given of an embodiment in which the present invention is applied to a diesel engine for an automobile.
As shown in Fig. 1, a diesel engine 12 mounted in an automobile 11 has a crankshaft (output shaft) 13 which is rotatably supported. A piston 14, which is provided in such a manner as to be capable of reciprocating, is connected to the crankshaft 13 through a connecting rod 15. The reciprocating movement of the piston 14 is converted to the rotation of the crankshaft 13 by the connecting rod 15. An engine speed sensor 13a for detecting the number of revolutions of the engine is provided on the side of the crankshaft 13.
Further, a combustion chamber 16 located in correspondence with the head 14a of the piston 14 is provided in the diesel engine 12, and an intake passage 17 and an exhaust passage 18 are connected to the combustion chamber 16. A throttle valve 19 is provided in the intake passage 17, and the opening of the throttle valve 19 is adjusted by being rotated by the driving of an electric motor 19a. Through the adjustment of the opening of the throttle valve 19, the air circulating area of the intake passage 17 changes, and the amount of air sucked into the combustion chamber 16 is regulated.
The diesel engine 12 has a fuel injection nozzle 21 for injecting high-pressure fuel into the combustion chamber 16, and the high-pressure fuel is injected into the combustion chamber 16 by the fuel injection nozzle 21 in the final stage of the compression stroke. If the fuel thus injected and supplied is ignited by the compression heat of the air and burns, the piston 12 reciprocates by the energy generated as a result of the combustion, and the diesel engine 12 obtains a driving force.
In this embodiment, the crankshaft 13 of the diesel engine 12 is connected to an automatic transmission 23 of a four-speed type. Further, the automatic transmission 23 is connected to wheels 24 of the automobile 11 through a propeller shaft, a differential, an axle shaft, and the like which are not shown. Further, the automatic transmission 23 has a speed-changing hydraulic controlling device 23a, and the speed-changing operation including the shiftup and shiftdown is effected through oil pressure control by the device 23a.
Meanwhile, the automobile 11 is provided with an accelerator pedal 25, which serves as an acceleration and deceleration commanding means, and a vehicle speed sensor 27. The accelerator pedal 25 is operated as the driver presses down on the pedal 25, and the amount of the pedal 25 pressed (accelerator opening) is detected by an accelerator sensor 28. In addition, the aforementioned vehicle speed sensor 27 is adapted to detect the vehicle speed of the automobile 11 on the basis of the rotating speed of an unillustrated output shaft of the automatic transmission 23.
Next, referring to Fig. 2, a description will be given of an electric configuration of a torque controlling apparatus in accordance with an embodiment of the invention. In this embodiment, the torque controlling apparatus serves as a fuel injection controlling apparatus for performing fuel injection control.
This fuel injection controlling apparatus has an electronic control unit (hereafter referred to as the "ECU") 92 for controlling the operating state of the diesel engine 12. This ECU 92 is configured as a logical operation circuit having a ROM 93, a CPU 94, a RAM 95, a backup RAM 96, and the like.
Here, the ROM 93 is a memory in which various control programs, maps which are referred to at the time of execution of the various control programs, and the like are stored. The CPU 94 executes arithmetic operations on the basis of the various control programs and maps stored in the ROM 93. In addition, the RAM 95 is a memory for temporarily storing the results of operation by the CPU 94 and data and the like inputted from various sensors, and the backup RAM 96 is a nonvolatile memory storing data to be preserved when the diesel engine 12 is stopped. The ROM 93, the CPU 94, the RAM 95, and the backup RAM 96 are connected to each other via a bus 97, and are connected an external input circuit 98 and an external output circuit 99.
The engine speed sensor 13a, the vehicle speed sensor 27, and the accelerator sensor 28 are connected to the external input circuit 98. Meanwhile, the fuel injection nozzle 21 and the speed-changing hydraulic controlling device 23a are connected to the external output circuit 99.
The ECU 92 thus configured determines the amount of the accelerator pedal 25 pressed on the basis of a detection signal from the accelerator sensor 28, and controls the fuel injection nozzle 21 in accordance with a predetermined control map so that the amount of fuel injection from the fuel injection nozzle increases with an increase in the amount stepped.
In addition, the ECU 92 determines the amount of the accelerator pressed and the vehicle speed of the automobile 11 on the basis of the detection signals from the accelerator sensor 28 and the vehicle speed sensor 27. Then, on the basis of the amount of the accelerator pressed and the vehicle speed thus determined, the ECU 92 determines a shift position in the automatic transmission by referring to a speed-changing map shown in Fig. 3, and controls the driving of the speed-changing hydraulic controlling device 23a so that the automatic transmission 23 will shift to the determined shift position.
It should be noted that the shift from the first gear to the second gear, the shift from the second gear to the third gear, and the shift from the third gear to the fourth gear are respectively performed by using the solid lines A, B, and C in the drawing as boundaries. On the other hand, the shift from the fourth gear to the third gear, the shift from the third gear to the second gear, and the shift from the second gear to the first gear are respectively performed by using the broken lines D, E, and F in the drawing as boundaries. The broken lines D, E, and F are located by being offset leftward in the drawing from the solid lines A, B, and C, respectively. If the broken lines D, E, and F coincide with the solid lines A, B, and C, the speed change of the automatic transmission 23 would be frequently effected when the throttle opening and the vehicle speed are in a state in which they are located on these lines. However, by offsetting the broken lines D, E, and F from the solid lines A, B, and C, it is possible to prevent the frequent shifts in the automatic transmission 23.
Next, referring to the time charts shown in Figs. 4A to 5C, a description will be given of an outline of the form of fuel injection control in accordance with this embodiment which is executed through the above-described ECU 92. It should be noted that the time charts in Figs. 4A to 4D respectively show forms of changes in the amount of fuel injection and in the engine speed NE when the automatic transmission 23 is in the first to the fourth gears and the above-described fuel injection control is executed. In addition, the time charts in Figs. 5A to 5C respectively show forms of changes in the amount of fuel injection, the engine speed NE, and an engine speed variation value DLNES, which will be described later, when the automatic transmission 23 is in the second gear and the above-described fuel injection control is executed.
If the driver abruptly stamps on the accelerator pedal 25 at the time of such as an acceleration of the vehicle, the amount of fuel injected increases sharply, and the output torque of the diesel engine 12 increases sharply, thereby increasing the rotating force of the crankshaft 13. If the rotating force of the crankshaft 13 is thus increased sharply, when the rotation is transmitted from the shaft 13 to the automatic transmission 23, a strong force which tends to twist the automobile 11 to the rotating direction of the crankshaft 13 is applied to the automobile 11. Then, if the strong force in the twisting direction is applied to the automobile 11, vibrations acting in the back-and-forth direction occur in the automobile 11, and the rotational speed NE of the engine 12 fluctuates due to the vibrations.
The form of such fluctuations in the engine speed NE differs depending on the shift position of the automatic transmission 23. Here, the forms of fluctuations in the engine speed NE in the respective shift positions of the automatic transmission 23 are shown in Figs. 4A to 4D. Figs. 4A to 4D show the forms of fluctuations in the engine speed NE in cases where the shift position of the automatic transmission 23 is in the first to fourth gears, respectively. As is apparent from these drawings, the period of variation in the engine speed NE becomes gradually longer as the shift position shifts consecutively from the first gear toward the fourth gear. The reason for this is that as the shift position shifts consecutively from the first gear toward the fourth gear, the speed reduction ratio of the automatic transmission 23 becomes gradually smaller, and the force which is applied to the automobile 11 and tends to twist it in the rotating direction of the crankshaft 13 becomes smaller.
If the accelerator pedal 25 is pressed abruptly when the shift position of the automatic transmission 23 is in, for instance, the second gear, the engine speed NE fluctuates with respect to the elapsed time in the form shown in Fig. 5B. The ECU 92 stores as a reference engine speed ACNEI the value at the time when the engine speed NE has begun to increase, and calculates as the engine speed variation value DLNES a value obtained by subtracting the aforementioned reference engine speed ACNEI from the present engine speed NE. The engine speed variation value DLNES thus calculated fluctuates with respect to the elapsed time in the form shown in Fig. 5(c).
The ECU 92 calculates the fuel correction value in accordance with the aforementioned engine speed variation value DLNES, and starts the execution of fuel-injection-amount correction based on the aforementioned fuel correction value with a predetermined phase difference  with respect to, the start of variation in the engine speed NE. Through this fuel-injection-amount correction, the amount of fuel injection fluctuates with respect to the elapsed time in the form shown in Fig. 5A. In this embodiment, the value of the aforementioned phase difference  is set so that the increase and the decrease in the output torque of the engine 12 based on the increase and the decrease in the amount of fuel injection will occur during the drop in the number of revolutions and the rise in the number of revolutions in fluctuations in the engine speed NE, respectively.
Generally, it is after the burning of fuel and the movement of the piston subsequent to the execution of fuel injection that the increase or decrease in the amount of fuel injected is actually reflected on the increase or decrease in the output torque of the engine 12. For this reason, since the aforementioned phase difference  is provided from the start of variation in the engine speed NE until the start of execution of the aforementioned fuel-injection-amount correction, the increase or decrease in the output torque of the engine 12 can be allowed to take place appropriately during the drop in the number of revolutions and the rise in the number of revolutions in the fluctuations in the engine speed NE. Consequently, the vibrations occurring during such as the acceleration of the automobile 11 are suitably suppressed, thereby improving the comfort of riding in the automobile 11.
It should be noted that the aforementioned phase difference  is set in correspondence with the shift position of the automatic transmission 23. Namely, as shown in Figs. 4A to 4D, the phase difference  is set to a greater value as the shift position of the automatic transmission 23 shifts from the first gear toward the fourth gear, i.e., in the direction in which the speed reduction ratio of the transmission 23 becomes consecutively smaller. Then, by executing the fuel-injection-amount correction with respect to the fluctuations in the engine speed NE with a predetermined incremental pattern by providing the phase difference  set in correspondence with the shift position of the automatic transmission 23, the suppression of vibrations in a manner similar to the aforementioned case of the second gear can be attained in whichever position the shift position of the automatic transmission 23 may be. The reason for the fact that suitable vibration control can thus be attained by making the phase difference  different in correspondence with the shift position is that the smaller reduction ratio of the automatic transmission 23 in terms of the shift position, the longer the period of variation in the engine speed NE.
Next, referring to Figs. 6 to 8, a description will be given of a procedure of fuel Injection control (hereafter referred to as jerk control) in accordance with this embodiment. Figs. 6 and 7 are flowcharts illustrating a processing routine for executing the jerk control. This processing routine is executed by angle interruption at each predetermined crank angle through the ECU 92.
In the processing routine, as processing in Step S101 the ECU 92 determines whether or not a condition for execution of jerk control has become valid, on the basis of an increment in the amount of fuel injection during a predetermined-period (e.g., 0.1 second). Namely, in a case where the amount of fuel injection increases during such as the acceleration of the automobile 11, and its increment is greater than a predetermined threshold value, a determination is made that a condition for execution of jerk control has become valid, and the operation proceeds to Step S102. On the other hand, if an increment in the amount of fuel injection is less than or equal to the predetermined threshold value, a determination is made that a condition for execution of jerk control has not become valid, and the operation proceeds to Step S120.
As processing in Step S120 the ECU 92 sets a control execution flag XJ to "0." This control execution flag XJ is for determining whether or not the jerk control for suppressing the vibrations occurring during the acceleration of the automobile 11 is being presently executed. Subsequently, the operation proceeds to Step S121 (Fig. 7), and as processing in Step S121 the ECU 92 sets as a final fuel injection amount QFIN the amount of fuel injection calculated from a known map on the basis of the amount of the accelerator pressed as an upper-limit guard, and then the operation proceeds to Step S119. The aforementioned map is determined in advance through an experiment and is stored in the ROM 93.
As processing in the ensuing Step S119, the ECU 92 determines the engine speed NE on the basis of the detection signal from the engine speed sensor 13a, and calculates the final fuel injection timing from a known map on the basis of the engine speed NE and the amount of fuel injected. After the final fuel injection timing is thus calculated, the ECU 92 temporarily ends this processing routine. After the final fuel injection amount QFIN and the final fuel injection timing are set as described above, the ECU 92 controls the driving of the fuel injection nozzle 21, and allows fuel of a value corresponding to the final fuel injection amount QFIN to be injected at the final fuel injection timing.
On the other hand, if a determination is made in the aforementioned Step S101 (Fig. 6) that the condition for execution of jerk control has become valid, and the operation proceeds to Step S102, as processing in Step S102 the ECU 92 sets "1" in the RAM 95 as the control execution flag XJ. The operation then proceeds to Step S103 in which the ECU 92 determines whether or not it is the first time that the condition for execution of jerk control has become valid. If "NO" is the answer in the determination in Step 103, the operation proceeds to Step S108 (Fig. 7), while if "YES" is the answer in the determination, the operation proceeds to Step S104.
As processing in Step S104, the ECU 92 determines a ratio between the engine speed NE and the amount of the accelerator pressed, and determines the present shift position in the automatic transmission 23 by referring to the known map on the basis of the ratio. It should be noted that a description will be given hereafter under the assumption that the shift position of the automatic transmission 23 is in the second gear.
As processing in an ensuing Step S105, the ECU 92 calculates an initial value of a final subtraction value QACCO and a jerk controlling time t on the basis of the shift position calculated above. The final subtraction value QACCO is obtained by subtracting from the aforementioned final fuel injection amount QFIN, and becomes gradually smaller with the lapse of time, as shown in Fig. 5A. In addition, the aforementioned jerk controlling time t corresponds to the time duration when the change in the engine speed NE during the sudden acceleration of the automobile 11 is effected for two to three periods. The initial value of the final subtraction value QACCO and the jerk controlling time t thus calculated are set to values suitable for suppressing the fluctuations in the engine speed NE by the fuel-injection-amount correction during jerk control.
As processing in an ensuing Step S106, the ECU 92 calculates the phase difference  until the start of fuel-injection-amount correction with respect to the start of variation in the engine speed NE occurring during such as the acceleration of the automobile 11, on the basis of the present shift position in the automatic transmission 23. This phase difference  is calculated as a value which becomes greater as the shift position shifts from the first gear toward the fourth gear, as shown in Figs. 4A to 4D. Subsequently, as processing in Step S107, the ECU 92 determines the number of fuel injections m (m is a natural number) effected while the crankshaft 14 rotates by the portion of the calculated phase difference q, and then the operation proceeds to Step S108 (Fig. 7).
As processing in Step S108, the ECU 92 sets as an engine speed difference DLNE a value obtained by subtracting the previous engine speed NEi-1 from the present engine speed NEi, and the operation proceeds to Step S109. As processing in Step S109, the ECU 92 determines whether or not the aforementioned engine speed difference DLNE is smaller than "0," i.e., whether or not the engine speed NE has declined. Then, if "DLNE <0," it is determined that the engine speed NE has declined, and the operation proceeds to Step S110. If it is not "DLNE <0," it is determined that the engine speed NE has increased, and the operation proceeds to Step S111.
As processing in Step S110, the ECU 92 increments an engine-speed drop counter N1 by "1," and resets an engine-speed rise counter N2 to "0." Meanwhile, as processing in Step S111, the ECU 92 increments the engine-speed rise counter N2 by "1," and resets the engine-speed drop counter N1 to "0." Accordingly, if the drop in the engine speed NE continues, the count of the engine-speed drop counter N1 becomes large, whereas if the rise in the engine speed NE continues, the count of the engine-speed rise counter N2 becomes large.
After the aforementioned Step S110 or S111, the operation proceeds to Step S112, and as processing in Step S112 the ECU 92 determines whether or the engine-speed rise counter N2 is at "1," i.e., whether or not the engine speed NE has just begun to increase. Then, if "N2 = 1," a determination is made that the engine speed NE has just begun to increase, and the operation proceeds to Step S113 in which the present the engine speed NE is set as the reference engine speed ACNEI. The operation then proceeds to Step S114. On the other hand, if it is not "N2 = 1," a determination is made that the engine speed NE has not begun to increase, and the operation proceeds directly to Step S114.
By executing the processing in the aforementioned Step S113, the reference engine speed ACNEI is set as shown in, for example, Fig. 5B, with respect to the variation in the engine speed NE occurring during the sudden acceleration of the automobile 11. As is apparent from this diagram, the reference engine speed ACNEI is reset to a new one each time the engine speed NE begins to rise. As processing in an ensuing step S114, the ECU 92 sets as the engine speed variation value DLNES a value obtained by subtracting the aforementioned reference engine speed ACNEI from the present engine speed NE. The engine speed variation value DLNES thus set changes with respect to the variation in the engine speed NE, as shown in Fig. 5C.
Subsequently, the operation proceeds to Step S115 in which the ECU 92 sets as an increment value tQACCE a value obtained by multiplying the aforementioned the engine speed variation value DLNES by a coefficient k. The coefficient k is for converting the engine speed variation value DLNES into the increment value tQACCE of the amount of fuel injection. In addition, a total of m (m is a natural number) increment values QACCE_m to QACCE1 having the relationship shown by Formulae (1) below are stored in the RAM 95 of the EGO 92.
In processing in Step S116, the EGO 92 resets the aforementioned increment value tQACCE as new QACCE₁, and resets the increment values QACCE_m to QACCE₂ to new values on the basis of the relationship shown in Formulae (1) above. Then, as processing in an ensuing Step S117, the ECU 92 resets the increment value QACCE_m as the final increment value QACCE. Accordingly, the final increment value QACCE is the increment value tQACCE calculated m times before.
As processing in Step S118, the EGO 92 sets as the final fuel injection amount QFIN a value in which the final subtraction value QACCO is subtracted from and the final increment value QACCE is added to the value determined by using as an upper-limit value the amount of fuel injection calculated from a known map on the basis of the amount of the accelerator pressed.
Here, referring to Fig. 8, a description will be given of a procedure for calculating the final subtraction value QACCO. Fig. 8 is a flowchart illustrating a processing routine for calculating the final subtraction value QACCO. This processing routine is executed by time interruption at each predetermined time through the ECU 92.
In the processing routine, as processing in Step S201 the ECU 92 determines whether or not the control execution flag XJ is set to "1," i.e., whether or not the jerk control for suppressing vibrations in the engine speed NE is being presently executed. Then, if it is not "XJ = 1," a determination is made that the jerk control is not being executed, and the operation proceeds to Step S205. As processing in Step S205, the ECU 92 sets the present reduction value QACCOi to "0," and as processing in an ensuing Step S204 sets the present reduction value QACCOi (in this case, "0") as the final reduction value QACCO. After the processing in Steps S205 and S204 is consecutively executed to the set the final reduction value QACCO to "0," the ECU 92 temporarily ends this processing routine.
Meanwhile, if it is "XJ = 1" in the aforementioned Step S201, a determination is made that the jerk control is being executed, and the operation proceeds to Step S202. As processing in Step S202, the EGO 92 sets as the present reduction value QACCOi a value obtained by subtracting a redetermined value ΔQ from the previous reduction value QAGGO_i-1 , and the operation then proceeds to Step S203. As processing in Step S203, the ECU 92 determines whether or not the present reduction value QACCO_i is greater than "0." Then, if "QACCO_i > 0" does not hold, the operation proceeds to Step S205, and after the processing in Steps S205 and S204 is consecutively executed in the same way as described above, this processing routine temporarily ends.
In addition, in the aforementioned Step S203, if "QACCO_i > 0," the operation proceeds directly to Step S204, and the present reduction value QACCO_i (in this case, a value greater than "0") is set as the final reduction value QACCO. After the final reduction value QACCO is set to a value greater than "0" by executing the processing in Step S204 in order, the ECU 92 temporarily ends this processing routine. Accordingly, by executing the processing routine, during the jerk control the final reduction value QACCO becomes gradually smaller with the lapse of time, as shown in Fig. 5A. It should be noted that a decrement in the final reduction value QACCO is determined by the magnitude of the predetermined value ΔQ in the aforementioned Step S202. The predetermined value ΔQ in this embodiment is set to such a value that the decrement in the final reduction value QACCO does not become excessively sharp.
Now, a description will return to the processing routine shown in Figs. 6 and 7. After executing the processing in the aforementioned Step S118 (Fig. 7), the ECU 92 executes the processing in the ensuing Step S119, and temporarily ends this processing routine. In addition, after the final fuel injection amount QFIN is set in the processing in the aforementioned Step S118, the ECU 92 controls the driving of the fuel injection nozzle 21 to cause the fuel injection nozzle 21 to inject fuel of a value corresponding to the final fuel injection amount QFIN.
By executing such control of the amount of fuel injection, the amount of fuel injection is increased or decreased with the phase difference , as shown in Fig. 5A, in the form shown in the drawing with respect to the variation in the engine speed NE. The reason for the fact that the phase difference  can be provided in the execution of the fuel-injection-amount correction with respect to the aforementioned variation in the engine speed NE is because, in the processing in the aforementioned step S116, the final increment value QACCE used in the aforementioned Step S118 is made the increment value tQACCE determined on the basis of the engine speed variation value DLNES calculated m times before.
Then, the increase in the output torque of the engine 12 due to the corrective increase in the amount of fuel injection occurs during the drop in the number of revolutions in the variation in the engine speed NE due to the aforementioned phase difference . Meanwhile, the decrease in the output torque of the engine 12 due to the decrease in the amount of fuel injection occurs during the rise in the number of revolutions in the variation in the engine speed NE due to the aforementioned phase difference . Accordingly, it becomes possible to suitably suppress the fluctuations in the engine speed NE and, hence, the vibrations of the automobile 11 occurring during the sudden acceleration.
It should be noted that although, in the foregoing description, it is assumed that the shift position of the automatic transmission 23 is in the second gear, even if the automatic transmission 23 is in a shift position other than the second gear, the fluctuations in the engine speed NE can be suppressed, and the vibrations of the automobile 11 can be suppressed in the same way as the case where the automatic transmission 23 is in the second gear.
In accordance with this embodiment in which processing is performed as detailed above, it is possible to obtain the following meritorious advantages.
The output torque of the diesel engine 12 does not change immediately when the amount of fuel injection is increased or decreased, but changes after the lapse of the period of fuel combustion and the period of movement of the piston 1 after the increase or decrease in the amount of fuel injection. Accordingly, with respect to variations in the engine speed NE occurring during a sudden acceleration of the automobile 11, the fuel-injection-amount correction in accordance with the variation in the engine speed NE is executed with the phase difference  with a predetermined incremental pattern, so that the variations in the engine speed NE can be suitably suppressed. Namely, an increase in the output torque of the engine 12 due to an increase in the amount of fuel injection occurs during the drop in the number of revolutions in fluctuations in the engine speed NE with the phase difference . Meanwhile, a decrease in the output torque of the engine. 12 due to a decrease in the amount of fuel injection occurs during the rise in the number of revolutions in fluctuations in the engine speed NE. As the output torque of the engine 12 is thus increased or decreased in correspondence with the fluctuations in the engine speed NE, it becomes possible to suitably suppress the fluctuations in the engine speed NE, and it hence becomes possible to suitably suppress the vibrations occurring in the automobile 11 during the sudden acceleration and the like.
Generally, as the shift position of the automatic transmission 23 shifts from the first gear toward the fourth gear, i.e., in the direction in which the speed reduction ratio of the transmission 23 becomes the smaller, the longer the period of variation in the engine speed NE occurring during such as a sudden acceleration. Hence, in this embodiment, the phase difference  is set to a greater value as the shift position of the transmission 23 shifts from the first gear toward the fourth gear. For this reason, in whichever shift position the automatic transmission 23 may be, the above-described fuel-injection-amount correction makes it possible to appropriately suppress the variations in the engine speed NE and the vibrations of the automobile 11 during such as the sudden acceleration.
In the case where the present invention is applied to the diesel engine 12 as in this embodiment, whether or not the operation of pressing on the accelerator pedal 25 has been effected to suddenly accelerate the automobile 11 can be accurately determined on the basis of changes in the amount of fuel injected. Accordingly, through the determination processing based on the amount of fuel injected in Step S101 (Fig. 6), it is possible to accurately determine whether or not the condition for execution of jerk control has become valid.
This embodiment may be modified, for instance, as follows.
Although, in this embodiment, the phase difference  is set to a different value for each of the shift positions (first to fourth gears) of the automatic transmission 23, the phase differences  for the first and second gears may be made common, and the phase differences  for the third and fourth gears may be made common. In this case, it suffices if the phase difference  for the first and second gears is set to an intermediate value between the phase difference q for the first gear and the phase difference  for the second gear in the foregoing embodiment, and the phase difference  for the third and fourth gears is set to an intermediate value between the phase difference  for the third gear and the phase difference q for the fourth gear in the foregoing embodiment. Even in such a modification, it is possible to obtain an advantage similar to the foregoing embodiment.
The aforementioned phase difference may be set to a fixed value irrespective of the shift position of the automatic transmission 23. In this case, it is preferable to set the phase difference  to a value for the first gear. This is because the vibrations occurring in the automobile 11 during such as a sudden acceleration become the largest when the shift position of the automatic transmission 23 is in the first gear.
Although, in this embodiment, an illustration is given of the case where the automatic transmission 23 is mounted in the automobile 11, a manual transmission may be mounted in the automobile 11 instead.
It is noted that the embodiment of the present invention is suitable for applying to a common rail type diesel engine because this type of the diesel engine has high degree of freedom for the fuel injection contol. However, it is not limited to apply to the common rail type diesel engine, but the embodiment of the invention is also applicable to other types of diesel engines. Instead of applying the present invention to the diesel engine, the present invention may be applied to a gasoline engine.
Althouth the torque controlling apparatus in the embodiment serves as the fuel injection controlling apparatus for controlling the amount of fuel injection, the torque controlling appratus according to the invention includes either apparatus for controlling a fuel injection timing, a fuel injection pressure, an ignition timing, or an amount of air.
Next, a technical concept, other than the claims, which can be ascertained from the above-described embodiment will be described together with its advantage.
In the torque controlling apparatus for a vehicle-mounted internal combustion engine according to the present invention, the suddenly-accelerating-operation detecting means detects the presence or absence of the suddenly accelerating operation by the acceleration and deceleration commanding means on the basis of changes in the amount of fuel injected and supplied. According to this arrangement, the operation for suddenly accelerating the vehicle can be accurately detected on the basis of changes in the amount of fuel injected and supplied into the internal combustion engine.
In accordance with the invention, although it takes time for the fuel-injection-amount correction with the aforementioned predetermined incremental pattern to be reflected on the suppression of the vibrations occurring due to the variation in the driving force from the internal combustion engine to the transmission, since the incremental pattern for increasing the amount of fuel injection with respect to the vibrations is provided with a phase difference, the aforementioned vibrations can be suitably suppressed by the phase difference.
In accordance with the invention, since the form of occurrence of vibrations occurring due to the variation in the driving force from the internal combustion engine to the transmission changes depending on the shift position of the transmission, by making variable the phase difference in the incremental pattern for increasing the amount of fuel injection with respect to the vibrations in correspondence with the detected shift position, the suppression of vibrations can be suitably attained in whichever shift position the aforementioned vibrations occur.
In accordance with the invention, the smaller the reduction gear ratio of the transmission in terms of the shift position, the larger the phase difference is set in the incremental pattern for increasing the amount of fuel injection with respect to the vibrations occurring due to the variation in the driving force from the internal combustion engine to the transmission. Therefore, the suppression of the vibrations can be attained more accurately in whichever position the shift position may be.
When an accelerator pedal (25) is suddenly stamped on, the amount of fuel injected into an engine (12) increases sharply, and the rotating force of a crankshaft (14) is increased, so that when the rotation is transmitted from the shaft (14) to an automatic transmission (23), a force which tends to twist an automobile (11) in the rotating direction of the shaft (14) is applied to the automobile (11). Consequently, the automobile (11) vibrate in the back-and-forth direction, and variations occur in the engine speed. The variations in the engine speed and the vibrations of the automobile (11) are suppressed by executing fuel-injection-amount correction corresponding to the variations in the engine speed with a predetermined phase difference and an incremental pattern with respect to the variations. As the phase difference () is thus provided, the output torque of the engine (11) which changes by lagging behind the fuel-injection-amount correction can be suitably regulated so as to suppress the variations in the engine speed.

Claims

A torque controlling apparatus for a vehicle-mounted internal combustion engine, comprising:

acceleration and deceleration commanding means (25, 28) operative externaly;

suddenly-accelerating-operation detecting means (13a, 27) for detecting the presence or absence of a suddenly accelerating operation by said acceleration and deceleration commanding means (25, 28); and

means (92), when the presence of the suddenly accelerating operation is detected by said suddenly-accelerating-operation detecting means (13a, 27), for correcting the torque of the engine using a predetermined phase difference () and a torque varying pattern both which are predetermined with respect to the accelaration condition of the engine in order to suppress vibrations occurring due to a variation in a driving force from said internal combustion engine to said transmission (23).
The torque controlling apparatus for a vehicle-mounted internal combustion engine according to claim 1, characterized by further comprising:

shift-position detecting means (92) for detecting a shift position of said transmission (23),
wherein said correcting means (92) makes variable the phase difference () in the torque varying pattern to be imparted in correspondence with the detected shift position.
The torque controlling apparatus for a vehicle-mounted internal combustion engine, according to claim 1, characterized in that:

fuel injecting means (21) is further provided, for injecting and supplying fuel in an amount correspondence with operation of said acceleration and deceleration commanding means (25, 28) into the vehicle-mounted internal combustion engine connected to a transmission (23);

said correcting meeans (92) includes fuel-injection-amount correcting means (92), when the presence of the suddenly accelerating operation is detected by said suddenly-accelerating-operation detecting means (13a, 27), for correcting the amount of fuel injected and supplied with a predetermined phase difference () and an incremental pattern with respect to the vibrations in order to suppress vibrations occurring due to a variation in a driving force from said internal combustion engine to said transmission (23).
The torque controlling apparatus for a vehicle-mounted internal combustion engine according to claim 3, characterized by further comprising:

shift-position detecting means (92) for detecting a shift position of said transmission (23),
wherein said fuel-injection-amount correcting means (92) makes variable the phase difference () in the incremental pattern to be imparted in correspondence with the detected shift position.
The torque controlling apparatus for a vehicle-mounted internal combustion engine according to claim 4, characterized in that the smaller the reduction ratio of the shift position detected by said shift-position detecting means, the larger said fuel-injection-amount correcting means (92) sets the phase difference () in the incremental pattern to be imparted.
The torque controlling apparatus for a vehicle-mounted internal combustion engine according to any one of claims 3 to 5, characterized in that the value of the phase difference () is set so that the increase and the decrease in the output torque of the engine (12) based on the increase and the decrease in the amount of fuel injection will occur during the drop in the number of revolutions and the rise in the number of revolutions in fluctuations in the engine speed (NE).
The torque controlling apparatus for a vehicle-mounted internal combustion engine according to claim 6, characterized in that the time (t) for correcting the amount of fuel by said fuel-injection-amount correcting means (92) corresponds to the time duration when the change in the engine speed (NE) during the sudden acceleration of the vehicle (11) is effected for two to three periods.