JPH1191410A - Vehicular output torque control device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prevent a burden of a driving system from becoming excessive, and provide a torque characteristic to satisfy both a low speed stage and a high speed stage by variably controlling output torque of an engine according to a selected speed change stage of a transmission. SOLUTION: Output torque of an engine is increased/decreased according to a selected speed change stage of a transmission 2 connected to the engine, and is outputted to front and rear or left and right driving wheels through a differential mechanism and a driving shaft, but at this time, a speed change stage of the transmission 2 is detected by a speed change stage detecting means 17, and output torque of the engine outputted to the driving wheels is restricted by an engine torque upper limit setting means 31 according to a detected speed change stage, and driving wheel output torque generated in the driving wheels is also restricted within a prescribed value.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an output torque control device for a vehicle, such as an automobile, for controlling output torque output from an engine to driving wheels in accordance with a shift speed of a transmission.

[0002]

2. Description of the Related Art In recent years, when controlling output of an engine provided in a vehicle such as an automobile, input information (accelerator operation information) from a driver is converted into an electric control signal, and the electric control signal is transmitted through the electric control signal. A so-called drive-by-wire (DBW) method has been developed and put into practical use. According to the control by the DBW, based on not only the accelerator operation information of the driver but also various other input information, optimal engine control suitable for the operating state of the engine and the like is performed while responding to the driver's request. It is possible.

[0005] For example, FIG. 5 schematically shows an engine control system based on DBW. As shown in FIG.
An electronic control unit (ECU) 102 is provided for controlling the output of the engine 101. An accelerator position sensor (APS) 103 detects the depression state (depressed opening degree) of an accelerator pedal (not shown) of the driver, and inputs the electric control signal (accelerator opening signal) from the APS 103 to the ECU 102. It has become.

The ECU 102 has, for example, a control map that determines the value of the output torque with respect to the accelerator opening and the number of revolutions of the engine.
A target output torque is set based on the accelerator opening signal input from the APS 103 and the current engine speed, and further corrected based on other engine information to determine the target output torque. That is, instead of outputting a torque corresponding to the depression amount (opening degree) of the accelerator pedal of the driver as it is, a correction according to various operating state information of the engine is performed to output an optimal torque for the current operating condition. It is assumed that.

When the target output torque is determined as described above, the actual output torque is adjusted so as to be the target output torque. In the case of a diesel vehicle, the adjustment of the fuel is performed by adjusting the control sleeve. This is performed by controlling the supply amount. That is, the position of the control sleeve can be set in accordance with the target output torque. Generally, a position sensor [here, a sleeve position sensor (SP
S)] based on the sleeve position signal input from 104
The output torque is controlled by adjusting the fuel injection amount by performing feedback control of the sleeve position using a solenoid or the like.

[0006] In the case of a spark ignition type engine (for example, a gasoline-powered vehicle), the output torque is adjusted by the opening of a throttle valve instead of the control sleeve. Also in this case, the throttle valve is adjusted to a throttle opening corresponding to the target output torque by feedback control based on a throttle opening signal input from a position sensor (throttle position sensor (TPS)) 104 provided in the throttle valve. The output torque is controlled by adjustment.

[0007]

As shown in FIG. 5, the torque output from the engine 101 is transmitted from a differential mechanism 106 to a driving wheel 107 via a transmission 105 connected to the engine 101. When passing through the transmission, the rotational speed is changed according to the gear position of the transmission, and the magnitude of the torque is also changed. That is, when the torque output from the engine is constant, the torque generated on the wheels increases as the shift speed is lower, and decreases as the shift speed is higher.

Accordingly, if the accelerator pedal opening is large at the first, second or reverse low speed, the torque generated on the wheels becomes excessive. In particular, when starting with the accelerator pedal fully depressed, the wheels and the road surface are not connected. During this time, a large torque equal to or greater than the maximum frictional force may be generated from the wheels, causing unstable vehicle behavior. When such an excessive torque is generated in the low-speed gear, the strength of the drive system such as a transmission, a differential mechanism, and a drive shaft is adjusted so as to withstand the excessive torque in the low-speed gear.
It is necessary to ensure durability, but in this case, there also arise problems that the weight of the drive system increases and the cost increases. Therefore, when the low gear is selected, in order to secure the stability of the vehicle behavior and reduce the load on the drive system, it is better that the engine does not have a large output torque.

On the other hand, in the fourth and fifth high speeds, it is desirable that the engine be capable of generating a large output torque in order to generate sufficient torque on the wheels in order to ensure power performance during high-speed running. In general, when the accelerator opening is maximized, the torque output from the engine becomes a maximum value according to the engine speed regardless of the gear position. By the way, the conventional engine output control system using the DBW described above basically controls the output torque of the engine in accordance with the amount of depression of the accelerator pedal, and regardless of the gear selected by the transmission, Normally, an output torque is output from the engine substantially corresponding to the accelerator opening. Therefore, if the accelerator pedal is fully opened, regardless of the selected gear position,
The output torque of the engine becomes a maximum value according to the engine speed. For this reason, if the output torque of the engine is set with emphasis on the running stability at the low speed stage and the reduction of the load on the drive system, sufficient drive wheel output torque cannot be obtained at the high speed stage, and the high speed running performance will be degraded. Conversely, if the engine output torque is set with emphasis on high-speed driving performance in the high-speed gear, the output torque of the driving wheels will be excessive in the low-speed gear, resulting in deterioration of running stability and an increase in the load on the drive system. Had a problem to do.

Japanese Patent Application Laid-Open Nos. 62-20647 (first prior art) and Japanese Unexamined Patent Application Publication No. 2-136567 (second prior art) disclose the prior art for controlling the engine in accordance with the gear position of the transmission. Some have been disclosed. In the first prior art, the drivability is improved by changing the opening degree characteristic of the throttle valve with respect to the amount of depression of an accelerator pedal according to the shift speed, but the magnitude of the output torque itself at each shift speed is increased. However, the object of the present invention is not to solve the problem, but to make the output torque follow-up characteristic to the accelerator operation. Therefore, such a technique cannot be used as a solution to the above-described problem.

In the second prior art, knocking is prevented in a low speed stage by setting an optimum ignition timing according to a shift speed, and a decrease in output due to a delay in ignition timing is prevented in a high speed stage to improve engine performance. It is intended to sufficiently draw out the engine and to make the combustion of the engine satisfactorily performed, and not to perform output torque control according to the gear position. Not be.

SUMMARY OF THE INVENTION The present invention has been made in view of such a problem, and variably controls the output torque of an engine in accordance with a selected shift speed of a transmission so that a load on a drive system is not excessively increased. It is another object of the present invention to provide a vehicle output torque control device capable of obtaining torque characteristics satisfying both a low speed stage and a high speed stage.

[0013]

According to a first aspect of the present invention, there is provided an output torque control apparatus for a vehicle, wherein an output torque of an engine is controlled by a selected shift speed of a transmission connected to the engine. And is output to the front and rear or left and right drive wheels via the differential mechanism and the drive shaft. At this time, the gear position of the transmission is detected by the gear position detecting means, and according to the detected gear position. Thus, the output torque of the engine output to the drive wheels by the output torque limiting means is limited. For this reason, for example, the output torque output to the drive wheels can be prevented from becoming excessive even in the low-speed stage.

In the vehicle output torque control device according to the present invention, the output torque of the engine is increased or decreased in accordance with the selected shift speed of the transmission connected to the engine, and is transmitted via the differential mechanism and the drive shaft. The gear position of the transmission is detected by the gear position detecting means at this time, and the output torque limiting means generates the driving wheel output at the driving wheels according to the detected gear position. The torque is limited within a predetermined value. For this reason, for example, even at a low speed, the drive wheel output torque generated at the drive wheels can be prevented from becoming excessive.

[0015]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to the drawings. FIGS. 1 to 3 show an output torque control device for a vehicle as an embodiment of the present invention. First, the configuration of a vehicle to which the present vehicle output torque control device is applied will be briefly described. A vehicle (automobile) according to the present embodiment is a four-wheel drive vehicle having a diesel engine and a manual transmission, As shown in FIG. 1, the engine (diesel engine) 1
The transmission (manual transmission) 2 directly connected to the gearbox reduces the rotational speed to a required number of revolutions, and a center differential (differential mechanism)
3. The selection of the reduction ratio at this time is performed by operating the transmission lever 16 to operate a transmission mechanism (not shown) inside the transmission 2, and here, five forward speeds are provided for first to fifth speeds. In reverse, only one shift stage is provided.

Also, naturally, the center differential 3
The engine torque input from the engine 1 is amplified in the transmission 2 in inverse proportion to the degree of deceleration of the rotational speed. Then, the torque input to the center differential 3 is distributed and output to the front and rear propeller shafts (drive shafts) 6 and 7, and the front wheels are shifted right and left by the front differential (differential mechanism) 4 from the propeller shaft 6. The output is distributed to front wheels (drive wheels) 12 and 13 via front axles (drive shafts) 8 and 9, and the rear wheels are distributed to the left and right by a rear differential (differential mechanism) 5 from a propeller shaft 7 and a rear axle. (Drive shafts) 10 and 11 are output to rear wheels (drive wheels) 14 and 15.

In this way, the engine torque output from the engine 1 is shifted by the transmission 2 and output to the front, rear, left and right wheels 12, 13, 14, and 15 via each mechanism. The magnitude of the output torque of the engine output to 12, 13, 14, and 15 is controlled by an electronic control unit (ECU) 30.

That is, the ECU 30 has a conventional DB
Similarly to the output torque control device for a vehicle under the control of W, an accelerator opening signal from an accelerator position sensor (APS) 19, an engine speed signal from an engine speed sensor (omitted in FIG. 1), a sleeve position sensor The control sleeve position signal and various other operating state information (for example, intake air temperature and atmospheric pressure, etc.) from the (SPS) 23 are input. A detection signal (gear position signal) of the selected gear position of the transmission 2 is input. The ECU 30 determines the engine 1 based on these signals.
Is performed.

Here, the configuration of the output torque control device for a vehicle will be described in detail. As shown in FIG. 2, the amount of depression (opening degree) of the accelerator pedal 18 and the command of the engine output torque, which are the engine output torque request commands, are shown in FIG. The engine speed is detected by an accelerator position sensor (APS) 19 and an engine speed sensor 20, respectively. The target output torque setting means (target torque setting means) 32 provided in the ECU 30 as an accelerator opening signal and an engine speed signal. Is to be entered.

On the other hand, the gear position of the transmission 2 is detected by a gear position detection switch (gear position detecting means) 17. The shift position detection switch 17 is, for example,
The shift speed is provided for each shift rail (not shown) of the transmission 2, and the shift speed is detected from the longitudinal movement of the shift rail by the shift operation of the shift lever 16, and the detected shift speed detection signal is provided to the ECU 30. The torque upper limit value setting means (output torque limiting means) 31 is inputted.

The torque upper limit value setting means 31 includes a reverse torque upper limit value setting means 31a, a first speed torque upper value setting means 31b, and a second speed torque upper value setting means, corresponding to the reverse and forward first to fifth speeds. 31c, third speed torque upper limit setting means 3
1d, 4th speed torque upper limit setting means 31e, and 5th speed torque upper limit setting means 31f. When a gear position detection signal is inputted from the gear position detection switch 17, one of the torque upper limit value setting means 31a corresponding to the selected gear position,
31b, 31c, 31d, 31e, 31f are selected,
The torque upper value setting means 31a, 31b, 31c, 3
The target output torque (target torque) of the engine is set by the target torque setting means 32 based on the upper limit values of 1d, 31e and 31f.

That is, in the target torque setting means 32,
The engine target output torque is set using a control map as shown in FIG. 3A based on a torque upper limit value setting signal in addition to the accelerator opening signal and the engine speed signal. Curves T _LR and T _{LR in} the map of FIG.
_L1 , _TL2 , _TL3 , _TL4 , and _TL5 all indicate the upper limit value of the output torque with respect to the engine speed, and the upper limit curves _TLR , _TL1 , _TL2 , _TL3 , _TL4 , _TL4 , 1 out of T _L5
The function of selecting one and determining the map is performed by the reverse torque upper limit value setting means 31a, the first speed torque upper limit value setting means 31b, 2
A high speed torque upper limit setting unit 31c, a third speed torque upper limit setting unit 31d, a fourth speed torque upper limit setting unit 31e, and a fifth speed torque upper limit setting unit 31f. In the target torque setting means 32, the torque upper value setting means 31 (31a, 31b, 31c, 31d, 31e,
The target output torque is set based on a map determined by the torque upper limit set in 31f).

Here, the first speed torque upper limit value setting means 31b
Torque upper limit value T _L1 , second speed torque upper limit value setting means 3
Maximum torque T _L2 by 1c, 3-speed torque upper limit setting unit 31d by the torque upper limit value T _L3, 4-speed torque upper limit setting unit maximum torque T _L4 by 31e, 5-speed torque upper limit setting unit 31f maximum torque by Comparing T _L5 , the torque upper limit value is lower at lower speed stages and is higher at higher speed stages (that is, T _L1 <T _L2 <T _L3 <T _L4 <
T _L5 ). Also, the maximum torque T _LR by reverse torque upper limit setting unit 31a is the first speed torque upper limit setting unit 31b
_Is approximately equal to the torque upper limit value T _L1 .

This is because the torque output from the engine 1 is limited in accordance with the gear position, so that the torque is amplified by the transmission 2 and the differential mechanisms 3, 4, 5 and the drive shafts 6, 7, 8,
This is to prevent the torque transmitted to 9, 10, and 11 from becoming excessive. That is, with respect to the output torque generated by the engine 1, the torque transmitted from the drive wheels to the road surface (the output torque generated by the drive wheels) increases as the shift speed becomes lower, and the load on the drive system is accordingly reduced. Will increase. Further, the torque transmitted from the drive wheels 12, 13, 14, 15 to the road surface is also limited due to the grip force of the tire and the like. Therefore, the engine output torque is limited so as to limit the output torque generated by the drive wheels to a predetermined value or less set according to the strength of the drive system, the grip force of the tire, and the like.

FIG. 3B is a control map for setting the target engine torque from the accelerator opening signal and the engine speed signal regardless of the gear position, that is, ignoring the torque setting signal. Corresponds to a control map of a conventional vehicle output torque control device. In the control based on this control map, for example, the engine speed is about 3000
rpm, depresses the state of the accelerator opening is about 25% (point indicated in P ₁₎ rapidly the accelerator pedal 18 up to 60% accelerator opening, the engine speed and the accelerator opening to the target engine torque (P ₂ set points indicating) is, the engine torque increases from T ₁ regardless gear position to T _2. When the accelerator opening is 100%, the maximum torque at the engine speed is output regardless of the gear position.

On the other hand, in the control of the present apparatus based on the map shown in FIG. 3A, for example, when the gear is in the first speed, the engine speed is about 3000 rpm and the accelerator opening is about 25% ( If the state of point) shown in P ₁ is depressed rapidly the accelerator pedal 18 up to 60% accelerator opening, the target engine torque when there is no torque limit P ₂
However, as shown in FIG. 3A, the torque upper limit values T _L1 , T _L2 , T _L3 , T _L4 , and T _L are changed according to the shift speed as shown in FIG.
_L5, since T _LR is set, the engine torque never exceeds the upper limit value T _L1, the target engine torque P ₃
Is set to the point Therefore, the engine torque is T ₁₂
To the upper limit value T _L1 with the accelerator opening, but after that, it does not rise no matter how much the accelerator is depressed.

When the target engine torque is determined in this way, the target torque setting means 32 further corrects the target engine torque based on various operating state information (for example, intake air temperature correction and atmospheric pressure correction). The target sleeve position is set based on the corrected target engine torque and engine speed, and output to the sleeve position controller 33.

The sleeve position controller 33 includes:
The solenoid 24 is controlled according to the target sleeve position, and the control sleeve 2 provided in the fuel injection pump 21 is controlled.
The position 2 (sleeve position) is adjusted. The control sleeve 22 is provided with a sleeve position sensor (SPS) 23, and the sleeve position controller 33 performs feedback control of the solenoid 24 based on the sleeve position signal detected by the SPS 23.

Since the vehicle output torque control apparatus according to one embodiment of the present invention is configured as described above, during operation, the engine torque is controlled, for example, according to the flow shown in FIG. As shown in FIG.
Is started (Step S00), the gear position detection switch 17 provided in the transmission 2 detects which gear position is selected, and inputs a gear position detection signal to the ECU 30 (Steps S01, S02, S02). S03, S04, S
05, S06).

Then, in the ECU 30, one of the corresponding torque upper limit value setting means 31a, 31 based on the gear position detection signal by the torque upper limit value setting means 31.
b, 31c, 31d, 31e and 31f are selected. That is, the upper limit values T _LR , T _L1 ,
One of _TL2 , _TL3 , _TL4 , and _TL5 is selected to determine a target output torque setting map.

The target torque upper limit setting means 32 uses the torque setting map determined in this way to execute APS 1
Opening signal from engine 9, engine speed sensor 20
The target engine torque is determined based on the rotation speed signal from the engine. Then, the target engine torque is corrected based on various operation state information (for example, intake air temperature correction and atmospheric pressure correction).
The target sleeve position is determined from the corrected target engine torque and engine speed, and output to the sleeve position controller 33.

The sleeve position controller 33 includes:
Via the solenoid 24 in response to this target sleeve position signal.
And electrically moving the control sleeve 22
The fuel injection amount is adjusted so that the engine torque reaches a predetermined value.
(Steps S11, S12, S13, S1)
4, S15, S16). The ECU 30 is provided with a gear position detection switch.
Whether the gear position detection signal input from the switch 17 is constant
It is determined whether the switching has been performed (steps S21, S22, S
23, S24, S25, S26), the gear position detection signal
Constant, that is, when the gear position is constant, the target torque setting means
32, the upper torque limit (T_LR, T_L1, T_L2, T_L3,
T_L4, T _L5) Is maintained as it is, and
When the output signal changes, that is, another change occurs in the transmission 2.
When the speed is selected, the torque upper limit value setting means is again set.
One of the torque upper limit value setting methods corresponding to 31
Steps 31a, 31b, 31c, 31d, 31e, 31f
Select and reset the upper torque limit to reduce the engine torque.
adjust.

As described above, according to the output torque control device for the vehicle, the gear position selected by the transmission 2 is detected by the gear position detection switch 17 and the torque upper limit setting means 31 is used to set the engine torque for each gear position. Since we set the upper limit,
At low speeds such as first speed and reverse, the torque upper limit values T _L1 and T _LR
, It is not necessary to perform excessive reinforcement in consideration of destruction due to excessive torque, and the drive shafts 6, 7, 8, 9, 1 are not limited to the transmission 2, the differential mechanisms 3, 4, 5, and the like.
The rational design of 0, 11, wheels 12, 13, 14, 15 and a suspension (not shown) is possible, which contributes to weight reduction and cost reduction.

Further, the torque generated on the wheels 12, 13, 14, 15 is also suppressed to prevent the wheels 12, 13, 14, 15 from idling with respect to the road surface particularly at the time of starting or sudden acceleration from a low speed. Therefore, there is an advantage that the behavior of the vehicle can be stabilized. Furthermore, in the fourth and fifth gears, the torque upper limit values T _L4 and T _L5 are increased or the upper limit values are released so that the maximum engine torque can be output, so that sufficient power performance can be obtained even during high-speed driving. Can be secured.

It should be noted that the present invention is not limited to the above-described embodiment, and can be implemented with various modifications without departing from the spirit of the present invention. For example, the number of gears can be applied to other gears, such as four forward gears or six gears. Of course, in the above-described embodiment, the transmission 2
Is described as a manual transmission. However, it is of course possible to apply the vehicle output torque control device of the present invention even in the case of an automatic transmission. The gear position is detected by extracting a gear position detection signal from an electronic control CPU provided in the machine.

In addition, the present invention can be applied not only to the diesel engine of the embodiment but also to a gasoline engine. In this case, the throttle valve servo drive is controlled by a throttle valve controller in accordance with a target throttle opening. The engine torque is controlled by adjusting the opening (throttle opening) of a throttle valve provided in the intake passage. The throttle valve controller performs feedback control of a throttle control servomotor based on a throttle opening signal detected by a throttle position sensor (TPS) provided in the throttle valve.

Further, the control of the output torque during normal running is performed by using the map shown in FIG. 3A, and when a large torque is required such as when climbing a steep hill, FIG. It is also possible to configure so that control is performed using a map A shown in FIG.

[0038]

As described above in detail, according to the vehicle output torque control device of the present invention, the gear position selected by the transmission is detected by the gear position detecting means, and the selected gear position is detected. Since the output torque (the output torque of the engine or the output torque of the drive wheels) output to the drive wheels via the transmission, the differential mechanism, and the drive shaft is limited according to the gear, the transmission, the differential mechanism, and the drive It is possible to reduce the load on the drive system such as the shaft breaking.

Therefore, it is not necessary to reinforce these drive systems in consideration of destruction due to excessive torque, so that not only transmissions, differentials, and drive shafts but also rational designs of wheels, suspensions, and the like are required. This makes it possible to contribute to weight reduction and cost reduction. In addition, since the output torque generated in the driving wheels can be limited, the vehicle behavior can be stabilized by suppressing the torque to a required value such that the front and rear wheels or the left and right wheels do not spin on the road surface. it can.

[Brief description of the drawings]

FIG. 1 is a schematic diagram showing a configuration of a vehicle output torque control device as one embodiment of the present invention.

FIG. 2 is a functional block diagram showing a configuration of a vehicle output torque control device as one embodiment of the present invention.

FIG. 3 is a control map diagram of an output torque control device for a vehicle as one embodiment of the present invention, and FIG.
FIG. 3B is a control map diagram using a conventional DBW.

FIG. 4 is a flowchart showing a processing flow of output torque control of a vehicle output torque control device as one embodiment of the present invention.

FIG. 5 is a schematic diagram showing a configuration of a conventional vehicle output torque control device.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Engine 2 Transmission 3,4,5 Differential mechanism 6,7,8,9,10,11 Drive shaft 12,13,14,15 Wheel (drive wheel) 16 Shift lever 17 Gear speed detection sensor (speed detection Mechanism) 18 accelerator pedal 19 accelerator position sensor 20 engine speed sensor 21 fuel injection pump 22 control sleeve 23 sleeve position sensor 24 solenoid 30 ECU 31 torque upper limit value setting means (output torque limiting means) 32 target output torque setting means 33 sleeve position controller

 ──────────────────────────────────────────────────の Continuation of the front page (72) Inventor Masao Utsumi 5-33-8 Shiba, Minato-ku, Tokyo Mitsubishi Motors Corporation

Claims (2)

[Claims] 1. A transmission connected to an engine, a differential mechanism capable of distributing an output torque from the transmission to front and rear or left and right drive wheels, and a drive connecting the differential mechanism and the drive wheels. And a transmission for transmitting the output torque from the engine to the drive wheels via the transmission, the differential mechanism, and the drive shaft. And output torque limiting means for limiting an engine output torque generated by the engine in accordance with a selected shift speed of the transmission detected by the shift speed detecting means. Torque control device. 2. A transmission connected to an engine, a differential mechanism capable of distributing an output torque from the transmission to front and rear or left and right drive wheels, and a drive connecting the differential mechanism and the drive wheels. And a transmission for transmitting the output torque from the engine to the drive wheels via the transmission, the differential mechanism, and the drive shaft. Means, and output torque limiting means for limiting the drive wheel output torque generated by the drive wheels to within a predetermined value according to the selected shift speed of the transmission detected by the shift speed detecting means. Output torque control device for a vehicle.