JPH07329609A - Power train control device at the time of turning travel of vehicle - Google Patents

Abstract

PURPOSE:To slight an automatic transmission to a low speed side at the time of turning travel and secure an engine brake at the time of turning travel and after that, enhance the performance of acceleration and further prevent an abrupt change of torque even at the time of this speed change. CONSTITUTION:When a controller 3 judges turning travel from a yaw rate PHI, a controller 8 commands the change of the transmission gear ratio of an automatic transmission 2 to a low speed side. At the same time, a command for the correction of a throttle opening is sent to a throttle actuator 5 so as to cancel the change of the output torque of the transmission due to the change of the transmission gear ratio. The change of the transmission gear ratio to a low speed side secures an engine brake at the time of turning travel and at the same time assures the enhancement of the performance of acceleration after that. Also, the correction of the throttle valve opening does not produce the change of the output torque of a transmission even by the change of the transmission gear ratio to smooth the start of turning travel.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an engine, such as an electronically controlled throttle, whose output is determined by a throttle valve whose opening can be controlled separately from the driver's accelerator pedal operation, and an automatic transmission. The present invention relates to a power train control device at the time of turning traveling of a vehicle having the following power train.

[0002]

2. Description of the Related Art An automatic transmission, regardless of whether it is a step-variable transmission or a continuously variable transmission, calculates a gear ratio suitable for the present operating condition from the combination of engine operating load and vehicle speed, In order to achieve the above, electronically controlled gear shift control is being widely used. In the case of such an electronically controlled automatic transmission, it is relatively easy to change the gear ratio.
As described in Japanese Patent No. 9330, the shift pattern is changed to facilitate the downshift while the vehicle is turning, and the downshift is triggered to ensure deceleration of the vehicle by the engine brake for turning. It is possible to realize control that is performed safely and that improves acceleration performance during subsequent reacceleration.

[0003]

However, such a change in the gear ratio inevitably causes a sudden change in the wheel drive force, and this change in drive force suddenly occurs irrespective of the driver's accelerator pedal operation. This makes it difficult to start a smooth turning drive, and also gives the driver a feeling of discomfort.

According to the present invention, in the case of a vehicle equipped with an engine having a throttle valve capable of changing the throttle opening degree separately from the driver's operation of the accelerator pedal as required, the above-mentioned abrupt change is made by modifying the throttle opening degree. It is an object of the present invention to realize the idea and solve the above problem from the viewpoint that the change in the wheel driving force can be canceled out.

[0005]

For this purpose, the power train control device for turning traveling according to the first aspect of the invention can control the opening degree independently of the accelerator pedal operation by the driver, as the concept is shown in FIG. In a vehicle having a power train including an engine whose output is determined by a different throttle valve and an automatic transmission, a turning running detection means for detecting turning running of the vehicle, and a time during which the running running is detected by the means. And a throttle valve for changing the output torque of the automatic transmission caused by the gear change by the turning gear ratio changing means for changing the output speed of the automatic transmission to a low speed side gear ratio. And a throttle opening correction means for correcting the opening.

In the power train control device of the second aspect of the invention, the turning traveling gear ratio changing means in the first aspect of the invention is characterized in that the amount of change of the gear ratio becomes smaller as the vehicle speed increases. It is a thing.

Further, in the power train control device of the third aspect of the invention, the turning gear ratio changing means in the first aspect of the invention increases the amount of change of the gear ratio as the yaw rate generated in the vehicle during turning is greater. It is characterized by having been made.

[0008]

In the first aspect of the invention, the output of the engine is controlled by the throttle valve, and the vehicle is driven by power from the power train including the engine and the automatic transmission.

Here, the turning traveling gear ratio changing means shifts the automatic transmission to a lower gear ratio while the turning traveling detecting means detects the turning traveling of the vehicle. Such a change in the gear ratio enhances the response gain of the engine with respect to the driver's operation, so that the vehicle can be reliably decelerated by the engine brake to safely perform the turning traveling, and the acceleration performance can be improved during the subsequent reacceleration. it can.

On the other hand, the throttle opening correction means corrects the throttle opening so that the change in the transmission output torque caused by the change in the gear ratio becomes small. Therefore, it is possible to mitigate a situation in which a change in the transmission output torque suddenly occurs irrespective of the driver's operation of the accelerator pedal even when the gear ratio is changed for the above purpose during turning. Therefore, it becomes possible to prevent the turning traveling from being smoothly started and to prevent the driver from feeling uncomfortable.

In the second aspect of the present invention, the above-described turning traveling gear ratio changing means reduces the amount of change of the gear ratio to the lower speed side as the vehicle speed increases. In this case, the change amount of the gear ratio accurately matches the turning traveling condition, is always appropriate without excess or deficiency, and the above-described effect can be more reliably achieved.

In the third aspect of the present invention, the above-described turning-travel gear ratio changing means increases the amount of change of the gear ratio to the lower speed side as the yaw rate acting on the vehicle during the turning travel increases. In this case as well, the change amount of the speed change ratio exactly matches the turning traveling condition, is always appropriate without excess or deficiency, and the above-described action and effect can be more reliably achieved.

[0013]

Embodiments of the present invention will now be described in detail with reference to the drawings. FIG. 2 is a system diagram illustrating a power train control device during vehicle turning according to the present invention. In the figure, 1 is an engine whose output is controlled by an electronically controlled throttle, 2 is an automatic transmission such as a continuously variable transmission, and a tandem coupling of the engine 1 and the automatic transmission 2 is a power train for a vehicle. Make up.

The engine 1 is controlled by the engine controller 3 via the system 4 in terms of fuel injection amount, ignition timing, exhaust gas recirculation amount, and the like.
The throttle opening (not shown) of the throttle valve (throttle opening) is controlled by the throttle actuator 5, and the engine output control is performed. In this engine output control, the engine controller 3 basically responds to a signal from the potentiometer 7 that detects the depression amount AC of the accelerator pedal 6 operated by the driver, and controls the throttle opening degree via the throttle actuator 5. For example, it is assumed that the opening degree is set to correspond to the depression amount AC of the accelerator pedal 6 according to the characteristics of FIG. 7.
At that time, the throttle opening sensor 10 detects the actual throttle opening and feeds it back.

The automatic transmission 2 may be a stepped automatic transmission, but here, it is a continuously variable transmission, and when the step motor 9 responds to a shift command from the transmission controller 8, a shift corresponding to the shift command is made. It is assumed that the gear ratio is changed to the selected state. Here, the transmission controller 8 basically responds to a signal from the potentiometer 7 that detects the depression amount AC of the accelerator pedal 6 and a signal from the vehicle speed sensor 11 that detects the vehicle speed V, and the accelerator opening AC and It is assumed that the gear ratio matching the driving condition is calculated from the combination of the vehicle speed V and the corresponding gear change command is output to the step motor 9.

In addition to the above-described normal engine control, the engine controller 3 adds a signal from the potentiometer 7 in addition to the signal from the potentiometer 7 for the purpose of the present invention to change the gear ratio and control the throttle opening during turning. , The signal from the throttle opening sensor 10 for detecting the throttle opening TH, the signal from the vehicle speed sensor 11 for detecting the vehicle speed V, and the signal from the yaw rate sensor 12 for detecting the yaw rate Φ acting on the vehicle are separately input. Then, the control program of FIG. 3 is executed based on these input information.

In FIG. 3, first, in step 21, the above input information is read, and then in step 22, the target gear ratio suitable for the operating condition is set to γ _S as follows.
To set. In this setting, the program of FIG. 4 is executed to make the setting, and first, step 31
At the accelerator pedal depression amount AC and vehicle speed V
Based on the map of FIG. 6, the target turbine rotational speed (target transmission input speed) obtains the N _TS, then the target turbine rotational speed N _TS at step 32, the transmission output rotational speed can be seen from the vehicle speed V ( k / V) to obtain the target gear ratio γ _S
To calculate.

In the next step 23 of FIG. 3, the target throttle opening TH _S corresponding to the accelerator pedal depression amount AC is searched based on the map of FIG. 7.

Next, at step 24 corresponding to the turning traveling detecting means, it is judged whether or not the vehicle is traveling by turning based on whether or not the yaw rate Φ is generated. Note that in this determination, instead of using the yaw rate Φ, it is possible to detect the steering angle of the steering wheel and determine whether or not the vehicle is turning by determining whether or not the steering angle is generated.

If the vehicle is not turning, the target throttle opening TH _S is output to the throttle actuator 5 in step 25, thereby setting the throttle opening TH to the target value TH _S, and the control proceeds to step 21. return. Therefore, when the vehicle is not turning, the throttle opening TH is controlled according to the accelerator pedal depression amount AC as usual, that is, as determined in step 23, and the transmission control of the automatic transmission is performed by the transmission controller 8. Let the control take place.

When it is determined in step 24 that the vehicle is turning, the target gear ratio γ _S set in step 22 is set in step 26, which corresponds to the gear changing means for turning.
The to the low-speed side only [Delta] [gamma] is corrected to update the gamma _S to γ _S = γ _S + Δγ. Then, in the next step 27, the transmission controller 8 is instructed to change the gear ratio. At this time, the transmission controller 8 changes the gear ratio to the low speed side so as to achieve the updated target gear ratio γ _S , prioritizing the above-described normal gear control. Such a change of the gear ratio to the low speed side makes it possible to ensure deceleration of the vehicle by the engine brake, to safely perform turning traveling, and to improve acceleration performance at the time of subsequent reacceleration.

The change amount Δγ of the gear ratio to the low speed side can be conveniently set to a constant value which roughly corresponds to the engine braking required for turning and the acceleration performance required thereafter, but it is preferable that FIG. As shown in, the vehicle speed V
The higher the vehicle speed, the smaller the change amount Δγ of the gear ratio to the low speed side, or the larger the yaw rate Φ acting on the vehicle during turning as shown in FIG. 9, the smaller the change amount Δγ of the gear ratio to the lower speed side. It is better to make it larger. In this case, the change amount Δγ of the speed change ratio accurately matches the turning traveling condition and becomes appropriate without any excess or deficiency that always matches the actual situation, and the appropriate engine braking is used to ensure deceleration of the vehicle for turning traveling. It is possible to more reliably achieve the function and effect of performing the operation safely and improving the acceleration performance in the subsequent re-acceleration.

The next step 28 in FIG. 3 corresponds to the throttle opening correction means. Here, the subroutine of FIG. 5 is executed so that the wheel driving force is not changed even if the gear ratio is changed. a correction throttle opening TH _c to seek, this is set to the target throttle opening degree TH _S. Therefore, in step 41 of FIG. 5, when the gear ratio (final reduction ratio) of the final drive gear is γ _F , the wheel turning radius is R, the target gear ratio is γ _S , and the turbine torque is T _t , the wheel driving force F is set. Is calculated by F = γ _F × R × γ _S × T _t . Here, γ _F , R and γ _S are already known, but the turbine torque T _t is the turbine torque T _t corresponding to the turbine speed N _TS based on the performance diagram of the torque converter of FIG. The map should be searched.

In step 42 of FIG. 5, the corrected target turbine torque T for keeping the wheel drive torque F unchanged by the above-mentioned change γ _S + Δγ of the gear ratio to the low speed side.
Calculate _t ′ by T _t ′ = F / [γ _F × R × (γ _S + Δγ)]. Next, at step 43, the turbine speed N _TS ′ that changes due to the change of the gear ratio to the low speed side γ _S + Δγ is calculated by N _TS ′ = [(γ _S + Δγ) × V] / k. Then, in step 44, a point X corresponding to these combinations is obtained from the corrected target turbine torque T _t 'and the turbine speed N _TS ' based on the torque converter performance diagram of FIG. Interpolation calculation based on the distances L ₁ and L ₂ to the throttle opening TH = 10% performance line and the throttle opening TH = 20% performance line, TH _C = 10 + [L ₁ / (L ₁ + L ₂ )] × 1
From 0, the corrected throttle opening TH _C is obtained. The corrected throttle opening TH _C is changed to the low speed side of the gear ratio γ
_S + Δγ also represents the throttle opening for keeping the wheel drive torque F calculated as above unchanged, and this is set as the target throttle opening TH _S.

In step 25 of FIG. 3, such a correction slot is
Tull opening TH_CTarget throttle opening TH set to
_SIs output to the throttle actuator 5.
The throttle opening of picture engine 1 to TH_CAnd eggplant When
Correct throttle opening TH _CShifts as described above
Change ratio to lower speed γ_SWheel drive torque can be increased by + Δγ
It's like keeping F constant, so turning
When changing the gear ratio for the above purpose,
However, the change in the wheel drive torque is due to the driver's accelerator pedal.
To avoid situations that may occur suddenly regardless of
And it became difficult to start turning smoothly.
It is possible to prevent the driver from feeling uncomfortable.
Become.

In the above-described example, the engine controller 3 determines whether the vehicle is turning and changes the gear ratio or corrects the throttle opening. However, the transmission controller 8 may execute these. Further, in the case where the engine and the automatic transmission are comprehensively controlled by one common controller, it is needless to say that the one common controller determines the change of the gear ratio and the correction of the throttle opening.

[0027]

As described above, the power train control device for turning traveling according to the first aspect of the present invention has a structure for shifting the automatic transmission to a gear ratio on the low speed side when turning, as described in claim 1. At the same time, it is possible to ensure deceleration of the vehicle by the engine brake and to perform the turning traveling safely, and to improve the acceleration performance in the subsequent re-acceleration.

In addition, since the throttle opening is modified so that the change in the transmission output torque caused by the change of the gear ratio is reduced, the gear ratio of Even if the change is made, it is possible to mitigate the situation where changes in the transmission output torque suddenly occur regardless of the driver's operation of the accelerator pedal, making it difficult to start turning smoothly and making the driver feel uncomfortable. It is possible to avoid remembering.

In the power train control device for turning according to the second aspect of the present invention, as described in claim 2, the higher the vehicle speed, the smaller the amount of change of the gear ratio to the low speed side. The amount exactly matches the turning conditions,
There is always an appropriate amount without excess and deficiency, and the above-mentioned action and effect can be achieved more reliably.

According to the third aspect of the present invention, the power train control device for turning traveling is configured such that, as the yaw rate acting on the vehicle during turning traveling increases, the change amount of the gear ratio to the low speed side increases. Therefore, also in this case, the change amount of the gear ratio accurately matches the turning traveling condition,
There is always an appropriate amount without excess and deficiency, and the above-mentioned action and effect can be achieved more reliably.

[Brief description of drawings]

FIG. 1 is a conceptual diagram showing a power train control device during vehicle turning according to the present invention.

FIG. 2 is a control system diagram of a vehicle power train showing an embodiment of a power train control device according to the present invention.

FIG. 3 is a flowchart showing a power train control program to be executed by the engine controller during turning travel in the same example.

FIG. 4 is a flowchart showing a subroutine relating to calculation of a target gear ratio in the same program.

FIG. 5 is a flowchart showing a subroutine relating to calculation of a corrected throttle opening in the same program.

FIG. 6 is a change characteristic diagram of a target turbine rotation speed used in calculating a target gear ratio.

FIG. 7 is a relationship diagram of a target throttle opening degree with respect to an accelerator pedal depression amount.

FIG. 8 is a change characteristic diagram of a gear ratio correction amount useful for the purpose of the present invention.

FIG. 9 is another change characteristic diagram of the gear ratio correction amount useful for the purpose of the present invention.

FIG. 10 is a performance diagram of a torque converter.

[Explanation of symbols]

 1 Electronically Controlled Engine with Throttle 2 Continuous Automatic Transmission 3 Engine Controller 5 Throttle Actuator 6 Accelerator Pedal 7 Potentiometer 8 Transmission Controller 9 Step Motor 10 Throttle Opening Sensor 11 Vehicle Speed Sensor 12 Yaw Rate Sensor

Claims (3)

[Claims] 1. A vehicle equipped with a power train including an engine and an automatic transmission, the output of which is determined by a throttle valve whose opening can be controlled separately from the driver's operation of an accelerator pedal. A turning traveling detection means for detecting, a turning traveling gear ratio changing means for shifting the automatic transmission to a low speed side gear ratio while the traveling is detected by the means, and the turning traveling gear ratio changing means. A power train control device at the time of turning traveling of the vehicle, comprising: a throttle opening correction means for correcting the opening of the throttle valve so that a change in output torque of the automatic transmission caused by a shift is reduced. 2. The power train control device according to claim 1, wherein the turning traveling gear ratio changing means is configured to reduce the amount of change in the gear ratio as the vehicle speed increases. 3. The vehicle according to claim 1, wherein the gear ratio changing means for turning travel is configured to increase the amount of change of the gear ratio as the yaw rate generated in the vehicle during turning travel increases. Power train control device when turning.