CN107848523B

CN107848523B - Automatic transmission control device and automatic transmission method

Info

Publication number: CN107848523B
Application number: CN201680044453.1A
Authority: CN
Inventors: 大岛达也; 角田进; 岸本义久
Original assignee: Isuzu Motors Ltd
Current assignee: Isuzu Motors Ltd
Priority date: 2015-07-31
Filing date: 2016-07-22
Publication date: 2020-05-26
Anticipated expiration: 2036-07-22
Also published as: WO2017022528A1; JP2017030529A; CN107848523A; JP6593016B2

Abstract

The automatic shift control device (20) is configured to perform the following control: after the AMT (15) is switched to the target gear (Gx), the clutch device (14) is connected in a half-clutch state, the output torque (Te) of the engine (11) is set to a first torque (Tc), and then, after the transmission shaft (16) generates torsion caused by the first torque (Tc), the output torque (Te) of the engine (11) is set from the first torque (Tc) to a required torque (Tb), and the clutch device (14) is completely connected from the half-clutch state.

Description

Automatic transmission control device and automatic transmission method

Technical Field

The present invention relates to an automatic shift control device and an automatic shift method, and more particularly, to an automatic shift control device and an automatic shift method that suppress shift shock generated when gears of an automatic mechanical transmission are automatically switched, shorten the time for switching gears, and improve drivability.

Background

In large-sized vehicles such as trucks and buses, there are vehicles equipped with an automatic transmission control device that automatically controls gear switching by providing a clutch device, a mechanical transmission, and the like with an actuator.

In gear switching of an automatic transmission (AMT) which is automatically performed by the automatic transmission control apparatus, control is performed to connect a clutch device after gear switching is completed to set an output torque of an engine to a torque desired by a driver. However, in this case, there is a problem that drivability deteriorates due to the shift shock.

In view of this, the following automatic shift control device is proposed: when the disengaged clutch device is temporarily engaged at the time of gear switching of the automatic mechanical transmission, the output torque of the engine is controlled so as to be a torque that cancels the rotational resistance of the engine (see, for example, patent document 1).

The device performs control to put the clutch device in a half-clutch state when a rotation speed difference between an engine rotation speed and a clutch rotation speed is within a predetermined value after gear switching of the automatic mechanical transmission is completed. Next, control is performed to set the output torque of the engine to a torque that cancels the rotational resistance of the engine. Then, after the clutch device is completely connected, the torque is raised to the torque desired by the driver.

Thus, after the gear switching is completed, fuel is injected to such an extent that torque that cancels the rotational resistance of the engine is generated, thereby avoiding deceleration due to the rotational resistance of the engine, thereby making it possible for no shift shock to occur.

Documents of the prior art

Patent document

Patent document 1: japanese patent laid-open publication No. 2006-70708

Disclosure of Invention

Problems to be solved by the invention

On the other hand, the inventors of the invention of the present application found that: after the clutch device is completely connected after the shifting, if the output torque from the engine is transmitted to the propeller shaft in a slightly twisted state during the running of the vehicle, the propeller shaft is twisted more than in a normal state, and the twist causes a backlash in the propeller shaft, which is a cause of shifting shock.

The backlash generated in the propeller shaft is caused by a phenomenon in which the propeller shaft is largely twisted by elastic deformation and a reaction force to be restored by the twist is amplified when a large output torque is transmitted from the engine after the clutch device is connected. When this backlash occurs, the torque change in the forward and reverse directions of the propeller shaft is amplified and appears due to the backlash from the drive wheel side. Then, the amplified torque change causes a torque variation transmitted to the wheel and a rotation variation of the wheel, and thus the vehicle largely swings in the front-rear direction. In particular, in a large vehicle, the transmission shaft is long, which results in a large elastic deformation amount and large vibration due to backswing, and therefore, a large shift shock is generated at the time of shifting.

In the above-described device, no countermeasure is taken against the backlash generated in the propeller shaft, which causes the shift shock. Specifically, when the output torque of the engine is increased to the torque desired by the driver after the clutch device is completely connected, the propeller shaft is largely twisted, and a backlash occurs in the propeller shaft. Therefore, there is a problem that the shift shock due to the backlash of the propeller shaft cannot be suppressed.

Further, if the output torque of the engine is gradually increased so as not to cause the backlash in the propeller shaft, it takes time to increase the output torque to the torque desired by the driver, which causes a problem of a long shift time.

The invention provides an automatic transmission control device and an automatic transmission method, which can reduce the transmission impact caused by the backswing generated on a transmission shaft when the gears of a mechanical automatic transmission are switched, shorten the time of gear switching and improve the driving performance.

Means for solving the problems

An automatic shift control device according to an aspect of the present invention includes: an engine, a clutch device for switching on/off a driving force from the engine, an automatic mechanical transmission connected to the engine via the clutch device and connected to a propeller shaft for transmitting the driving force to a driving wheel, and a control member connected to and controlling the engine, the clutch device, and the automatic mechanical transmission, respectively; the control unit performs the following control: after the automatic mechanical transmission is switched to a target gear according to the operating condition of the vehicle, the clutch device which is temporarily disengaged is connected, so that the output torque of the engine is set to the required torque required by the driver from the initial torque set according to the target gear; the control means performs control for engaging the clutch device in a half-clutch state after switching to the target gear, and performs control for setting an output torque of the engine to a first torque set between the initial torque and the requested torque; the control means performs control to set the output torque of the engine from the first torque to the required torque and to fully connect the clutch device from a half clutch state after the torque due to the first torque transmitted from the engine via the clutch device and the automatic mechanical transmission is generated in the propeller shaft.

An automatic transmission method according to one aspect of the present invention is an automatic transmission method in which, after a mechanical automatic transmission is switched to a target gear according to an operating condition of a vehicle, a clutch device that is temporarily disengaged is engaged, thereby setting an output torque of an engine from an initial torque set according to the target gear to a torque requested by a driver; the automatic transmission method performs the following control: after the shift to the target gear is made, the clutch device is connected in a half clutch state, the output torque of the engine is controlled to a first torque set between the initial torque and the requested torque, and after a torque is generated in a propeller shaft by the first torque transmitted through the clutch device and the automatic mechanical transmission, the output torque of the engine is set from the first torque to the requested torque, and the clutch device is completely connected in the half clutch state.

Effects of the invention

According to the automatic transmission control device and the automatic transmission method of the present invention, after the automatic mechanical transmission is switched to the target gear according to the operating condition of the vehicle, as a first stage, the clutch device is connected in the half-clutch state, and the output torque of the engine is initially set from the initial torque to the first torque, thereby causing the propeller shaft to be twisted in advance. In the second stage, after the propeller shaft is twisted, the output torque of the engine is set from the first torque to the required torque, and the reaction force to recover the twist of the propeller shaft is offset by the amount of increase from the first torque to the required torque. Then, the output torque of the engine reaches the required torque, and the clutch device is fully connected from the half-clutch state to complete the gear shift of the mechanical automatic transmission.

By performing such control, it is possible to suppress the backlash generated in the propeller shaft by the twisting of the propeller shaft. This makes it possible to avoid alignment due to backlash, to shorten the time required for gear switching, and to reduce the shift shock due to backlash, thereby improving drivability.

In particular, the present invention is effective in upshifting an automatic mechanical transmission, and can reduce a shift shock caused by a backlash generated in a propeller shaft in upshifting the automatic mechanical transmission, thereby improving drivability.

Drawings

Fig. 1 is a configuration diagram illustrating an automatic shift control device according to an embodiment of the present invention.

Fig. 2 is a flowchart illustrating an automatic shift control method according to an embodiment of the present invention.

Fig. 3 is a diagram illustrating an accelerator opening, an engine speed, a clutch speed, an output torque, and a clutch stroke in time series.

Fig. 4 is a diagram illustrating a first torque chart.

Fig. 5 is a flowchart illustrating a method of calculating the first torque.

Detailed Description

Embodiments of the present invention will be described below with reference to the drawings. Fig. 1 illustrates an automatic shift control device 20 according to an embodiment of the present invention. The automatic Transmission control device 20 is mounted on the vehicle 10, and performs control for automatically switching a mechanical automatic Transmission (hereinafter referred to as AMT)15 to a target gear Gx in accordance with an operating condition of the vehicle 10.

The vehicle 10 is a large vehicle such as a bus or a truck having an engine 11 made of a diesel engine. In this vehicle 10, a crankshaft 13 is rotationally driven by thermal energy generated by combustion of fuel in a plurality of (4 in this example) cylinders 12 formed in an engine 11. The rotational power of the crankshaft 13 is transmitted to the AMT15 through a dry clutch device (hereinafter, referred to as a clutch device) 14.

The AMT15 is exemplified by a main transmission mechanism capable of shifting an input rotational power in multiple stages and a sub-transmission mechanism capable of shifting a rotational power transmitted from the main transmission mechanism into two stages, i.e., a low-speed stage and a high-speed stage.

The rotational power shifted by the AMT15 is transmitted to the differential device 17 through the propeller shaft 16, and is distributed to the pair of drive wheels 19 as drive forces via the drive shafts 18, respectively.

The automatic shift control device 20 is configured to include: an engine control device 21 connected to the engine 11 and mainly controlling the engine 11; a transmission control device 22 connected to the clutch device 14 and the AMT15, respectively, and mainly controlling the clutch device 14 and the AMT 15; and an on-vehicle Network 23 such as a CAN (Controller Area Network) that enables data of these control devices to communicate with each other.

The engine control device 21 is connected to sensors such as an accelerator opening sensor 24 that detects the amount of depression of an accelerator pedal P1 as an accelerator opening AO and a crank angle sensor 25 that detects an engine rotation speed Ne. Then, the fuel injection amount from an electronically controlled injector (hereinafter referred to as an injector) 26 is adjusted based on the detected values thereof, and the increase and decrease of the output torque Te of the engine 11 is controlled.

The transmission control device 22 controls the clutch actuator 27 to control the operation of the clutch device 14. The operation control of the clutch device 14 is as follows: by supplying compressed air, not shown, to the clutch actuator 27, the clutch device 14 is disengaged by the clutch actuator 27 to block the transmission of the power from the engine 11, or by releasing the compressed air from the clutch actuator 27, the disengaged clutch device 14 is engaged to transmit the power from the engine 11 to the AMT 15.

The shift control device 22 is connected to a sensor such as a propeller shaft rotation speed sensor 28 that detects a propeller shaft rotation speed Np of the propeller shaft 16 or a vehicle speed V from the propeller shaft rotation speed Np. Then, the shift actuator 29 controls switching of the AMT15 to the target gear Gx according to the operating condition of the vehicle 10. The speed change actuator 29 is also operated by compressed air as in the clutch actuator 27, but these actuators may be electromagnetic actuators operated by electromagnets.

In addition, the transmission control device 22 is also connected to a clutch rotation speed sensor 30 that detects the clutch rotation speed Nc of the clutch device 14. The clutch rotation speed Nc is the rotation speed input from the clutch device 14 to the AMT15, and may be obtained from the transmission ratio between the propeller shaft rotation speed Np and the AMT15 without detecting the clutch rotation speed Nc by the clutch rotation speed sensor 30.

Here, the switching control to the target gear Gx according to the operating condition of the vehicle 10 will be described below as the function of the automatic shift control device 20. First, the speed change control device 22 acquires a vehicle speed V and an accelerator opening AO. Next, the gear shift control device 22 selects the target gear Gx based on the vehicle speed V and the accelerator opening AO, which are the operating conditions of the vehicle 10. More specifically, the transmission control device 22 refers to a shift map M1 stored in the transmission control device 22 in advance and having a target gear Gx set based on the vehicle speed V and the accelerator opening AO, and selects the target gear Gx based on the shift map M1.

Next, the gear shift control device 22 controls the clutch actuator 27 to disengage the clutch device 14, thereby blocking the transmission of power between the engine 11 and the AMT 15. Next, the engine control device 21 performs the following control: the fuel injection amount of the injector 26 is adjusted to set the output torque Te of the engine 11 to the initial torque Ta set in accordance with the selected target gear Gx.

For example, at the time of an upshift of the AMT15, the clutch device 14 is disengaged and the output torque Te of the engine 11 is reduced to the initial torque Ta. The disengagement control of the clutch device 14 and the reduction control of the output torque Te of the engine 11 may be performed simultaneously, and the output torque Te of the engine 11 may be set to the initial torque Ta gradually while the clutch device 14 is gradually disengaged.

The initial torque Ta is a torque set in advance for each gear of the AMT15, and is set to increase in proportion to the gear ratio. For example, in the case of a 12-stage transmission in which the main transmission of the AMT15 is six-stage and the sub-transmission is two-stage, the initial torque Ta is set for each of the 12 stages.

Next, the gear shift control device 22 controls the gear shift actuator 29 to shift the AMT15 to the target gear Gx. More specifically, the gear shift control device 22 controls the gear shift actuator 29 to disengage a synchronizer, not shown, that is synchronously engaged with the currently selected gear, and synchronously engage the synchronizer with the target gear Gx.

Next, the gear shift control device 22 controls the clutch actuator 27, connects the clutch device 14, and transmits the power from the engine 11 to the AMT 15. Next, the engine control device 21 adjusts the fuel injection amount of the injector 26 to set the output torque Te of the engine 11 to the required torque Tb required by the driver. More specifically, the transmission control device 22 sets the required torque Tb set based on the accelerator opening AO, and completes the gear change of the AMT 15.

For example, when the vehicle 10 is accelerated by the driver stepping on the accelerator pedal P1 during an upshift of the AMT15, the output torque Te of the engine 11 is increased to the required torque Tb after the AMT15 is switched to the target gear Gx, and the upshift of the AMT15 is completed.

In this way, when AMT15 is switched to target gear Gx according to the operating condition of vehicle 10, the following control is performed: the output torque Te of the engine 11 after the switch to the target gear Gx is set to the required torque Tb required by the driver. However, when the output of the engine 11 is directly set as the required torque Tb and the clutch device 14 that has been temporarily disengaged is completely connected, the propeller shaft 16 is greatly twisted by elastic deformation and a backlash occurs.

Therefore, the automatic shift control device 20 of the present invention is configured to perform the following control. As a first stage, after the target gear Gx according to the operating condition of the vehicle 10 is switched, control is performed to connect the clutch device 14 in the half-clutch state, and control is performed to set the output torque Te of the engine 11 to the first torque Tc set between the initial torque Ta and the required torque Tb. As a second stage, the following control is performed: after the first torque Tc transmitted from the engine 11 via the clutch device 14 and the AMT15 causes the propeller shaft 16 to twist, the output torque Te of the engine 11 is set from the first torque Tc to the required torque Tb, and the clutch device 14 is fully connected from the half-clutch state.

The first torque Tc is a torque set between the initial torque Ta and the required torque Tb, and is a torque larger than a torque that cancels out the rotational resistance of the engine 11. The magnitude of the first torque Tc determines the magnitude of the reaction force at the time of torsional recovery of the propeller shaft 16.

The first torque Tc is set by the gear shift control device 22 based on the rotation speed difference Δ Nec between the engine rotation speed Ne and the clutch rotation speed Nc or the rotation speed difference Δ Nx between the engine rotation speed Ne and the propeller shaft rotation speed Np. For example, the first torque Tc is set to be large to increase the reaction force at the time of the return of torsion when the difference between the initial torque Ta and the required torque Tb is large, and is set to be small to decrease the reaction force at the time of the return of torsion when the difference between the initial torque Ta and the required torque Tb is small. Further, the first torque Tc is set to be large to increase the reaction force at the time of the torsional return when the rotational speed difference Δ Nec between the engine rotational speed Ne and the clutch rotational speed Nc is large, and is set to be small to decrease the reaction force at the time of the torsional return when the rotational speed difference Δ Nec is small.

That is, the reaction force at the time of torsional recovery of the propeller shaft 16 is proportional to the magnitude of the first torque Tc. Therefore, it is desirable that the first torque Tc is set to a value such that the propeller shaft 16 reaches the preset torsion amount Qa after the output torque Te of the engine 11 is set to the required torque Tb. The torsion amount Qa is an amount of torsion of the propeller shaft 16 during traveling of the vehicle 10, and is obtained in advance through experiments or experiments.

By setting the first torque Tc in this way, the reaction force at the time of recovery of the torsion of the propeller shaft 16 to which the first torque Tc is transmitted by setting the output torque Te of the engine 11 as the first torque Tc can be cancelled by the torque of the phase difference when the output torque Te of the engine 11 is set from the first torque Tc to the request torque Tb, and the torsion of the propeller shaft 16 can be set as the torsion amount Qa during traveling to suppress the backlash of the propeller shaft 16.

The automatic gear shifting method according to the first embodiment of the present invention will be described as a function of the automatic gear shifting control device 20 with reference to a flowchart shown in fig. 2. In the following, the upshift of AMT15 will be described as an example. The automatic transmission method is started after the clutch device 14 is disengaged, the output torque Te of the engine 11 is reduced to the initial torque Ta set according to the target gear Gx, and the AMT15 is switched to the target gear Gx in the switching control to the target gear Gx described above.

First, in step S10, the gear shift control device 22 controls the clutch actuator 27 to connect the clutch device 14 in the half clutch state. The half clutch state is a state in which the clutch device 14 is fastened at about 50%, and some slippage may occur in the clutch device 14.

Next, in step S20, the engine control device 21 increases the output torque Te of the engine 11 to the first torque Tc. In step S20, the first torque Tc is transmitted to the propeller shaft 16 via the clutch device 14 and the AMT15, and the propeller shaft 16 is twisted by the first torque Tc by the twisting amount Qa or more during running. By the torsion generated on the propeller shaft 16 due to the first torque Tc, the reaction force of the torsion to be recovered is amplified on the propeller shaft 16.

Further, step S10 and step S20 are performed simultaneously. Next, in step S30, the gear shift control device 22 maintains the clutch stroke CS of the clutch actuator 27 in the half-clutch state set in step S10.

Next, in step S40, the gear shift control device 22 determines whether or not the rotation speed difference Δ Nec between the engine rotation speed Ne and the clutch rotation speed Nc is within a predetermined range set in advance.

The predetermined range is set as the following range: the engine rotation speed Ne, which becomes lower than the propeller shaft rotation speed Np of the propeller shaft 16 as the output torque Te of the engine 11 decreases to the initial torque Ta, can be determined to approach the clutch rotation speed Nc, which is the same rotation speed as the propeller shaft rotation speed Np. The predetermined range is set in advance by experiment or experiment, and is preferably set to a range in the vicinity of zero, for example. In the present embodiment, the lower limit value is set to zero, and the upper limit value is set to a value Δ Na in the vicinity of zero. The rotation speed difference Δ Nec may include a negative value, that is, the engine rotation speed Ne may be higher than the clutch rotation speed Nc, and the lower limit value may be set to a negative value.

In this step S40, in the case where the rotation speed difference Δ Nec is outside the predetermined range, the process returns to step S30, and on the other hand, in the case where the rotation speed difference Δ Nec is within the predetermined range, the process proceeds to step S50. When the process returns from step S40 to step S30, the engine rotation speed Ne may be controlled so that the rotation speed difference Δ Nec falls within a predetermined range. For example, when the rotation speed difference Δ Nec is smaller than the lower limit value, the fuel injection amount of the engine 11 may be increased, whereas when the rotation speed difference Δ Nec is larger than the upper limit value, the fuel injection amount of the engine 11 may be decreased.

By thus converging the rotation speed difference Δ Nec between the engine rotation speed Ne and the clutch rotation speed Nc within a predetermined range, it is possible to avoid the occurrence of torsion in the deceleration direction in the propeller shaft 16.

Next, in step S50, the engine control device 21 increases the output torque Te of the engine 11 from the first torque Tc to the required torque Tb. At this time, the reaction force of the torsional return of the propeller shaft 16 is cancelled by the output torque Te that increases to the required torque Tb of the engine 11, and the torsional state of the propeller shaft 16 reaches the torsional amount Qa.

Next, in step S60, the gear shift control device 22 controls the clutch actuator 27 to fully connect the clutch device 14, and the automatic gear shift method is completed. In addition, step S50 is performed simultaneously with step S60.

Fig. 3 illustrates an accelerator opening AO, an engine rotation speed Ne, a clutch rotation speed Nc, an output torque Te of the engine 11, and a stroke CS of the clutch actuator 27 in time series when the AMT15 is switched to the target gear Gx.

At time t1, disengagement of the clutch device 14 is started, and reduction of the output torque Te of the engine 11 is started. At time t2, disengagement of the clutch device 14 is completed, and the output torque Te of the engine 11 is reduced to the initial torque Ta.

At time t3, the switching to the target gear Gx from time t2 is completed, the clutch device 14 starts to be engaged in the half-clutch state, and the increase in the output torque Te of the engine 11 is started.

At time t4, the clutch device 14 is connected in the half clutch state, the output torque Te of the engine 11 increases to the first torque Tc, and the propeller shaft 16 is twisted by the twisting amount Qa or more. At time t5, the rotation speed difference Δ Nec between the engine rotation speed Ne and the clutch rotation speed Nc falls within a predetermined range, and at that moment, the rise of the output torque Te of the engine 11 is started. At the same time, the operation of the clutch actuator 27 is started, and the clutch device 14 is fully connected from the half-clutch state.

At time t6, the output torque Te of the engine 11 increases to the required torque Tb, and the clutch device 14 is in the fastened state of 100%, that is, the clutch device 14 is completely connected, and the automatic transmission method is completed.

As described above, after the AMT15 is shifted to the target gear Gx in accordance with the operating condition of the vehicle 10, the clutch device 14 is connected in the half-clutch state as the first stage, and the output torque Te of the engine 11 is initially set from the initial torque Ta to the first torque Tc, so that the torsion by the first torque Tc is generated on the propeller shaft 16. In the second stage, after the torque is generated in the propeller shaft 16, the output torque Te of the engine 11 is set from the first torque Tc to the required torque Tb, and the reaction force to recover the torque of the propeller shaft 16 is cancelled by the torque Δ T of the increase amount from the first torque Tc to the required torque Tb. Then, the output torque Te of the engine 11 reaches the required torque Tb, and the clutch device 14 is fully connected from the partially engaged state, completing the gear shift of the AMT 15.

By performing such control, the reaction force at the time of the return of the torsion of the propeller shaft 16 can be cancelled out by the torque Δ T of the increase amount. That is, the propeller shaft 16 is twisted a little by the first torque Tc, and when the twist is restored, the reaction force of the propeller shaft 16 is cancelled, so that the backlash due to the twist of the propeller shaft 16 can be suppressed.

This can suppress the backlash occurring in the propeller shaft 16 when the AMT15 is shifted to the target gear Gx, and can reduce the time t7 required for shifting the target gear Gx by avoiding the alignment caused by the backlash. Further, since the shift shock due to the backlash can be reduced, drivability can be improved.

In the automatic transmission control device 20 described above, the output torque Te of the engine 11 is increased from the initial torque Ta to the first torque Tc at the time of the upshift AMT15, and then the output torque Te is increased to the required torque Tb after the twist of the propeller shaft 16 is generated by the first torque Tc.

The automatic shift control device 20 described above is configured to have the first torque map M2. The first torque map M2 is a graph in which the target gear Gx is plotted on the vertical axis and the rotational speed difference Δ Nx between the target engine rotational speed Na and the actual engine rotational speed Ne is plotted on the horizontal axis. The first torque map M2 is set with a first torque Tc (Gx, Δ Nx) based on the target gear Gx and the rotational speed difference Δ Nx. The first torque Tc (Gx, Δ Nx) is set to a value that allows the propeller shaft 16, which has the output torque Te of the engine 11 set as the required torque Tb, to reach a preset torsion amount Qa.

The target engine speed Na is calculated from the propeller shaft speed Np of the propeller shaft 16 and the gear ratio of the target gear Gx. The actual engine rotation speed Ne is detected by a crank angle sensor 25. The target engine speed Na may be replaced with the clutch speed Nc, and the first torque map M2 may be set with the first torque Tc (Gx, Δ Necx) based on the target gear Gx and the speed difference Δ Nec.

Fig. 4 illustrates a first torque chart M2. The first torque map M2 is a map that is created in advance through experiments or experiments and is stored in the shift control device 22 in advance.

The method of calculating the first torque Tc (Gx, Δ Nx) will be described below as a function of the automatic shift control device 20 with reference to a flowchart shown in fig. 5.

First, in step S100, the gear shift control device 22 determines the target gear Gx. Next, in step S110, the gear shift control device 22 acquires the propeller shaft rotation speed Np from the propeller shaft rotation speed sensor 28.

Next, in step S120, the gear shift control device 22 calculates a target engine speed Na from the propeller shaft speed Np of the propeller shaft 16 and the gear ratio of the target gear Gx.

Next, in step S130, the engine control device 21 acquires the engine rotation speed Ne at the current time from the crank angle sensor 25, and the gear shift control device 22 receives the engine rotation speed Ne. Next, in step S140, the gear shift control device 22 calculates the rotation speed difference Δ Nx. The rotation speed difference Δ Nx is a value obtained by subtracting the engine rotation speed Ne from the target engine rotation speed Na at the time of the upshift.

Next, in step S150, the shift control device 22 refers to the first torque map M2. Next, in step S160, the gear shift control device 22 extracts the first torque Tc (Gx, Δ Nx) based on the target gear Gx and the rotation speed difference Δ Nx from the first torque map M2, and the calculation method is completed.

By calculating the first torque Tc (Gx, Δ Nx) from the first torque map M2 in this way, the amount of the first torsion of the propeller shaft 16 and the amount of torsion at the time of the return of the torsion can be easily calculated without performing complicated calculations, and therefore, complication of the control can be avoided.

In step S10 and step S20 of the above embodiment, step S20 may be started before step S10. Specifically, after the step of increasing the output torque Te of the engine 11 to the first torque Tc is started, the step of connecting the clutch device 14 in the half-clutch state may be started. Thus, the time taken for switching can be further shortened.

This application is based on the Japanese patent application (Japanese patent application 2015-152225) filed on 31/07/2015, the contents of which are incorporated herein by reference.

Industrial applicability

The disclosed vehicle control device can avoid alignment due to backlash, shorten the time required for gear switching, and reduce shift shock due to backlash, thereby improving drivability.

Description of reference numerals

10 vehicle

11 Engine

14 clutch device

16 drive shaft

20 automatic speed change control device

Gx target gear

Initial torque of Ta

Tb requested torque

Tc first torque

Claims

1. An automatic shift control device includes:

a control unit that is connected to an engine, a clutch device, and an automatic mechanical transmission, and that controls increase and decrease of an output torque of the engine, operation of the clutch device, and switching of gears of the automatic mechanical transmission, respectively; wherein the clutch device is configured to cut off/on a driving force from the engine, and the automatic mechanical transmission is connected to the engine via the clutch device and is connected to a power transmission shaft that transmits the driving force to a driving wheel,

the automatic transmission control device performs the following control: after the automatic mechanical transmission is switched to a target gear according to the operating condition of the vehicle, the clutch device which is temporarily disengaged is connected, so that the output torque of the engine is set to the required torque required by the driver from the initial torque set according to the target gear;

performing control for engaging the clutch device in a half-clutch state after the shift to the target gear, and performing control for setting an output torque of the engine to a first torque set between the initial torque and the requested torque based on a difference between an actual engine rotation speed and a target engine rotation speed;

when the propeller shaft is twisted by the first torque transmitted from the engine via the clutch device and the automatic mechanical transmission, control is performed to set the output torque of the engine from the first torque to the required torque and to completely connect the clutch device from a half-clutch state.

2. The automatic shift control device according to claim 1,

the shift to the target gear is an upshift of the automatic mechanical transmission.

3. The automatic shift control device according to claim 1,

after the transmission shaft is twisted by the first torque and the rotational speed difference is within a predetermined range set in advance, control is performed to set the output torque of the engine from the first torque to the required torque.

4. The automatic shift control device according to any one of claims 1 to 3,

the engine control device includes a calculating unit that calculates the target engine speed from a transmission shaft speed of the propeller shaft and a gear ratio of the target gear, calculates a speed difference between the target engine speed and the actual engine speed, and extracts the first torque from a first torque map in which the first torque is set for the target gear and the calculated speed difference.

5. An automatic transmission method in which a clutch device that is temporarily disengaged is connected after a mechanical automatic transmission is switched to a target gear according to the operating condition of a vehicle, and the output torque of an engine is set from an initial torque set according to the target gear to a torque required by a driver; the automatic speed changing method comprises the following steps:

connecting the clutch device in a half-clutch state after switching to the target gear;

calculating a first torque set between the initial torque and the required torque based on a difference between an actual engine speed and a target engine speed, the first torque set between the initial torque and the required torque, and setting an output torque of the engine as the calculated first torque;

when a torque is generated in a propeller shaft by the first torque transmitted through the clutch device and the automatic mechanical transmission, the output torque of the engine is set from the first torque to the required torque, and the clutch device is completely engaged from a half-clutch state.