JP2014134257A - Speed change gear of vehicle - Google Patents

Abstract

PROBLEM TO BE SOLVED: To surely increase brake force by an auxiliary brake by shifting a shift stage of a speed change gear in a state that the auxiliary brake is operated to a lower stage than a shift stage in a traveling state when shift-down control at the operation of the auxiliary brake is required.SOLUTION: A speed change gear of a vehicle comprises: a transmission 15; shift control means 18 which shifts up or shifts down the transmission 15 and performs shift control of the transmission 15 to a target shift stage which is obtained from a stepping-on amount of an accelerator pedal 11 or driver requirement torque; an auxiliary brake 13 which is operable in a state that the stepping-on amount of the accelerator pedal 11 is zero; and shift-down control means 21 which shifts down the transmission 15 when the auxiliary brake 13 is operated in a state that an operation switch 26 is turned on. The shift control means 18 holds the shift-up in the case that the stepping-on amount of the accelerator pedal 11 is reduced and reaches zero from the traveling state that the operation switch 26 is turned on, and the accelerator pedal 11 is pressed.

Description

  The present invention relates to a transmission for a vehicle that can automatically downshift in order to improve the effectiveness of an auxiliary brake.

  Conventionally, many commercial vehicles such as trucks are equipped with an automatic transmission. As such an automatic transmission device, there is known a device using a mechanical clutch and a gear-type transmission, provided with various sensors for detecting the operation state thereof and an actuator for driving these sensors (for example, Patent Documents). 1). In such a vehicle transmission device, instead of manually shifting with the driver's operating force, the control unit controls the actuator based on detection signals from various sensors, and the transmission is shifted up or down according to a predetermined shift map. Thus, the transmission is controlled to be shifted to the target shift speed obtained from the depression amount of the accelerator pedal or the driver required torque.

  In addition, such a relatively large vehicle includes an auxiliary brake such as an exhaust brake that operates when the accelerator is off or the main brake is on as an auxiliary to the main brake device. This auxiliary brake such as the exhaust brake operates when the driver releases the accelerator pedal and sets the depression amount to zero when the auxiliary brake is set to the effective state by the driver's switch operation. When the driver depresses the accelerator pedal, the auxiliary brake state is released and the vehicle can be accelerated.

  On the other hand, an auxiliary brake such as an exhaust brake may not be able to obtain a deceleration effect due to the gear ratio if the transmission is shifted up to a high gear number while traveling on a highway or the like. Therefore, in vehicles equipped with the above-described mechanical automatic transmission that has become widespread in recent years, when the auxiliary brake is operated, the transmission is automatically shifted down from a high number of steps to a low number of steps to increase the braking force by the auxiliary brake. Shift down control has been proposed (see, for example, Patent Document 2).

JP-A-6-241300 Japanese Patent Laid-Open No. 10-246321

  However, in the operation of the auxiliary brake, which is a condition for performing the downshift control, as shown in FIG. 5, the amount of depression of the accelerator pedal is decreased from the traveling state in which the accelerator pedal is depressed, and the final operation is performed. It is necessary to release the step and make the step amount zero. As described above, when the accelerator pedal is depressed from the traveling state where the accelerator pedal is depressed, but the amount of depression does not reach zero, the accelerator pedal depression amount or the driver requested torque is determined according to a predetermined shift map. Thus, the transmission is controlled to be shifted to the target shift speed obtained from the above. Here, in the conventional shift control, if the amount of depression of the accelerator pedal is reduced from the traveling state in which the accelerator pedal is depressed, the engine speed is reduced and the consumed fuel is suppressed. When passing through the predetermined shift-up line, a shift-up is performed in which the transmission stage number is changed to a higher stage number.

  Then, as shown in the shift control content of FIG. 5, if the accelerator pedal depression amount is gradually decreased from the traveling state where the accelerator pedal is depressed, the accelerator pedal depression amount becomes zero before the depression amount becomes zero. It will be shifted up once (t1). Then, after that, when the amount of depression of the accelerator pedal becomes zero (t2), the auxiliary brake is operated until the accelerator pedal is next depressed (t3). Then, the transmission is shifted down with the operation of the auxiliary brake (t2 to t3). As a result, the speed change state of the transmission in the state where the accelerator pedal is depressed and the state where the auxiliary brake is activated is the same, and the braking force by the auxiliary brake cannot be increased. Cause it to occur.

  It is an object of the present invention to make sure that the shift speed of the transmission when the auxiliary brake is operated is lower than the shift speed of the traveling state when the shift down control at the time of operation of the auxiliary brake is desired. An object of the present invention is to provide a vehicle transmission that can increase braking force.

  The present invention relates to a transmission, a shift control means for shifting the transmission to a target shift stage obtained from the accelerator pedal depression amount or driver required torque by shifting up or down the transmission, and the accelerator pedal depression amount. This is an improvement of a transmission device for a vehicle including an auxiliary brake that can be operated with zero and a shift-down control means that shifts down the transmission when the auxiliary brake is operated with an operation switch turned on.

  The characteristic configuration is that the shift control means suspends the upshifting when the operation switch is turned on and the accelerator pedal is depressed and the amount of depression of the accelerator pedal is reduced to zero from the running state. is there.

  In this case, a storage means for storing an accelerator pedal depression amount or a driver required torque for shifting up the transmission by reducing the accelerator pedal depression amount from a traveling state in which the accelerator pedal is depressed is provided. It is preferable to hold the upshift until the accelerator pedal depression amount or driver required torque reaches the accelerator pedal depression amount or driver required torque stored in the storage means after the up suspension.

  In the vehicle transmission of the present invention, since the shift up when the amount of depression of the accelerator pedal is reduced to zero from the traveling state in which the accelerator pedal is depressed is suspended, from the traveling state in which the accelerator pedal is depressed, The transmission is not shifted up until the amount of depression of the accelerator pedal is decreased and the amount of depression of the accelerator pedal becomes zero. When the accelerator pedal depressing amount becomes zero, the auxiliary brake is operated and shifted down. Therefore, the shift in the state where the auxiliary brake is operated from the shift stage of the traveling state before the accelerator pedal depressing amount is decreased. The gear position of the machine can be surely made low. As a result, the braking force by the auxiliary brake can be increased.

  Thereafter, when the accelerator pedal is depressed, the auxiliary brake is deactivated, the downshift by the downshift control means is released, and the transmission that has been downshifted is once shifted up. If the accelerator pedal depression amount or driver required torque when the auxiliary brake is deactivated is the accelerator pedal depression amount or driver required torque for shifting up the transmission, the transmission is controlled by the shift control means. It will be further shifted up. As a result, when the accelerator pedal is depressed from the state where the auxiliary brake is activated, a two-stage upshift is immediately performed, causing a problem that the engine speed is remarkably reduced and the driver feels uncomfortable.

  However, after the upshift has been suspended, the assistance of the accelerator pedal is continued by continuing the upshift until the accelerator pedal depression amount or the driver requested torque becomes the accelerator pedal depression amount or the driver requested torque for shifting up the transmission. It is possible to prevent the transmission from being shifted up by the shift control means when the brake is deactivated. As a result, a two-step upshift due to depression of the accelerator pedal is prohibited, and the driver does not feel uncomfortable due to the engine speed being significantly reduced at a time.

It is a flowchart which shows the operation | movement in the shift control means of the transmission of embodiment of this invention. It is a flowchart which shows operation | movement of the downshift control means of the transmission. It is a block diagram of the vehicle containing the transmission. It is a figure which shows the relationship between the judgment by the auxiliary brake switch, an accelerator pedal, and a shift map, the shift-up hold state, and the actual shift control content. It is a figure corresponding to FIG. 4 which shows the relationship between the judgment by the conventional auxiliary brake switch, an accelerator pedal, and a shift map, and the actual shift control content.

  Next, the best mode for carrying out the present invention will be described with reference to the drawings.

  FIG. 3 shows a main configuration of a vehicle 10 to which the transmission of the present invention is applied. The vehicle 10 is a large vehicle such as a truck. Although not shown, the vehicle 10 can directly brake the rotation of the front wheels 17a and the rear wheels 17b, and the main brake device can be used by a driver. A brake pedal that is actuated by depressing the pedal is provided. The vehicle 10 is provided with an exhaust brake 13 as an auxiliary brake that is activated when the accelerator pedal 11 is not depressed or when the main brake device is activated, as an auxiliary to the main brake device. . The exhaust brake 13 as an auxiliary brake is disposed in the exhaust passage of the engine 12 and includes an auxiliary brake ECU (electronic control unit) 14 that is a control device for the exhaust brake 13.

  A transmission 15 is connected to the engine 12, and a rear wheel 17 b is further connected via a shaft 16. The transmission 15 that transmits the output of the engine 12 to the rear wheel 17b is a mechanical automatic transmission 15 that is controlled by an automatic transmission ECU 18 that constitutes a transmission control means, and the automatic transmission ECU 18 shifts the transmission 15. It is configured to be up or down. The automatic transmission ECU 18 is provided with a memory 18a, and a memory 18a stores a shift map in which target shift stages according to conditions such as the amount of depression of the accelerator pedal 11 or driver required torque are described. Here, the driver request torque is obtained from the product of the throttle opening degree that opens and closes when the accelerator pedal 11 is depressed and the vehicle speed.

  Further, the vehicle 10 is provided with an engine ECU 19 that is a control device for the engine 12 and a downshift control ECU 21 that is a downshift control means for shifting down the transmission 15 when the auxiliary brake 13 is operated. The engine ECU 19 connects its control output to the fuel injection device 12 a in the engine 12. Further, the downshift control ECU 21 is configured to issue a command to the automatic transmission ECU 18 to execute the downshift accompanying the operation of the exhaust brake 13.

  Further, the vehicle 10 is provided with an accelerator sensor 24 that detects the amount of depression of the accelerator pedal 11 and a vehicle speed sensor 22 that detects the traveling speed of the vehicle. Further, the vehicle 10 is provided with an exhaust brake 13 that is an auxiliary brake and an operation switch 26 that enables a downshift when the exhaust brake is activated. The auxiliary brake ECU 14, automatic transmission ECU 18, engine ECU 19, shift down control ECU 21, vehicle speed sensor 22, accelerator sensor 24, operation switch 26 and the like described above are connected to other devices (not shown) via a CAN (Controller Area Network) 23. Connected and configured to communicate with each other.

  Then, when the driver depresses the accelerator pedal 11 and the vehicle 10 travels, the engine ECU 19 increases or decreases the flow rate of fuel supplied to the engine 12 in accordance with the amount of depression of the accelerator pedal 11, and the rotation of the engine 12 is desired. It is configured to maintain the rotation. When the depression amount of the accelerator pedal 11 or the traveling speed of the vehicle 10 detected by the vehicle speed sensor 22 changes, the automatic transmission ECU 18 serving as the shift control means obtains the target obtained from the depression amount of the accelerator pedal or the driver required torque. The transmission 15 is configured to shift-control to a shift stage. In other words, the automatic transmission ECU 18 shifts the transmission 15 up or down to change the transmission 15 to the target shift stage obtained from the depression amount of the accelerator pedal 11 or the driver required torque according to the shift map stored in the memory 18 a. Is configured to control the shift.

  On the other hand, when the driver releases the depression of the accelerator pedal 11 and the accelerator sensor 24 detects and outputs the fact that the accelerator pedal 11 is released, the engine ECU 19 determines the fuel flow rate supplied to the engine 12 as the engine flow rate. Twelve rotations are configured to be the minimum amount necessary to maintain at idling speed. For this reason, when the traveling gear is selected in the transmission 15 and the accelerator sensor 24 detects and outputs the fact that the accelerator pedal 11 is released while the vehicle 10 is traveling at a corresponding speed, the traveling speed is maintained at the idling speed. The engine 12 to be braked is in a so-called engine brake state in which the rotation of the rear wheel 17b is braked.

  The exhaust brake 13 in this embodiment has a structure in which an open / close valve is provided in the exhaust passage of the engine 12, and the driver operates the operation switch 26 in the state of the engine brake, whereby the auxiliary brake ECU 14 is operated. Is configured to close an on-off valve provided in the exhaust passage of the engine 12. When the on-off valve is closed, the engine 12 further reduces the rotational speed, whereby the exhaust brake 13 substantially acts as a brake on the vehicle 10.

  The operation switch 26 in this embodiment is configured such that the driver tilts the operation lever 26a, and the basic state indicated by the dotted line in FIG. 3 indicates the off state, and even in the engine brake state in this off state. The auxiliary brake ECU 14 is configured not to close an on-off valve (not shown) provided in the exhaust passage of the exhaust brake 13. When the operation lever 26a is tilted one step from the OFF state to the first tilted state indicated by the broken line, the on-off valve provided in the exhaust passage is closed in the engine brake state, and the rotational speed of the engine 12 is further reduced. Configured to let

  When the operation switch 26 in this embodiment is further tilted one step from the first tilted state indicated by the broken line to the second tilted state indicated by the solid line, the exhaust brake 13 is activated in the engine brake state. Then, further downshifting in the transmission 15 is performed. The downshift in the transmission 15 is realized when the downshift control ECU 21 issues a command to the automatic transmission ECU 18. That is, in the state where the operation lever 26a of the operation switch 26 is tilted so as to be in the second tilted state indicated by the solid line, when the engine brake state is entered, the downshift control ECU 21 issues a command to the automatic transmission ECU 18 to change the speed. The machine 15 is configured to perform a downshift.

  The automatic transmission ECU 18 is provided with a storage circuit 18b which is storage means for storing information in the memory 18a. The specific information stored in the memory 18a by the memory circuit 18b is the amount of depression of the accelerator pedal 11 that shifts up the transmission 15 by reducing the amount of depression of the accelerator pedal 11 from the traveling state where the accelerator pedal 11 is depressed. This is the driver request torque.

  On the other hand, the automatic transmission ECU 18, which is a transmission control means, is in a second tilting state in which the operation lever 26a of the operation switch 26 is turned on to allow downshifting during engine braking, and the accelerator pedal 11 is depressed. The shift-up operation is suspended when the amount of depression of the accelerator pedal 11 is reduced from the running state to zero. Then, the automatic shift ECU 18 serving as the shift control means has the accelerator pedal 11 in which the depression amount of the accelerator pedal 11 or the driver request torque detected by the accelerator sensor 24 is stored in the memory 18a by the storage circuit 18b after the upshift is suspended. Until the driver's required torque is reached again.

  Next, the operation of the vehicle transmission configured as described above will be described.

  First, FIG. 2 shows the control in the downshift control ECU 21 which is a downshift control means. As shown in FIG. 2, when the traveling gear is selected in the transmission 15 and the vehicle 10 is traveling at a corresponding speed, when the driver releases the depression of the accelerator pedal 11 to bring the engine into a brake state, the accelerator pedal is released. The fact that 11 is released is detected and output by the accelerator sensor 24. The downshift control ECU 21 that has detected that the engine is in the brake state (S21) based on this detection output is then operated by the operation switch 26 in the driver's seat and the operation lever 26a is in the off state indicated by the dotted line in FIG. It is confirmed whether it is in a state other than (S22). That is, the exhaust brake 13 as an auxiliary brake can be selected by the driver. As a result, when the operation lever 26a of the operation switch 26 is in the off state shown by the dotted line in FIG. 3, if the auxiliary brake has already been operated, the auxiliary brake is released (S24), that is, the exhaust brake 13 The opening / closing valve not shown in FIG.

  On the other hand, when the operation lever 26a of the operation switch 26 is in a position other than the OFF state indicated by the dotted line in FIG. 3, the driver expresses the intention to use the exhaust brake 13, and in this case, the downshift control is performed. Next, the ECU 21 checks whether or not the operation lever 26a of the operation switch 26 in the driver's seat is in the second tilted state indicated by the solid line in FIG. 3 (S23). That is, it is confirmed whether or not an intention to shift down when the auxiliary brake is operated is displayed. As a result, when the operation lever 26a of the operation switch 26 is not in the second tilted state shown by the solid line in FIG. 3, a command is issued to the auxiliary brake ECU 14 without shifting down, and the operation position of the operation lever 26a is Based on the above, the exhaust brake 13 which is an auxiliary brake is operated (S25), and the process returns. That is, when the operation lever 26a of the operation switch 26 is in the first tilted state shown by the broken line in FIG. 3, the on-off valve provided in the exhaust passage is closed and the exhaust brake 13 is operated. Therefore, when the driver does not like the downshift accompanying the operation of the exhaust brake 13, it can be selected not to execute the downshift.

  Conversely, when the operation lever 26a of the operation switch 26 is in the second tilted state shown by the solid line in FIG. 3, the downshift control ECU 21 issues a command to the automatic transmission ECU 18 to shift down the transmission 15, At the same time, a command is issued to the auxiliary brake ECU 14 to operate the exhaust brake 13 (S26), and the process returns. As a result, the braking force by the auxiliary brake can be increased.

  Next, the control in the automatic disguise ECU 18 that is a shift control means will be described. As shown in FIG. 4, when the amount of depression of the accelerator pedal is reduced from the traveling state where the accelerator pedal 11 is depressed, the transmission 15 of the shift map stored in the memory 18a is changed before the amount of depression becomes zero. It will pass through the upshift line to be shifted up. As shown in FIG. 1, when such a shift map determination result does not pass through the shift-up line, that is, when the shift map is not shifted up (S11), each time through the storage circuit 18b, The depression amount of the accelerator pedal 11 or the driver request torque is updated and stored in the memory 18a in the automatic transmission ECU 18 (S14).

  On the other hand, if the determination result of the shift map passes through the shift up line and shifts up, then the operation switch 26 is turned on and the operation lever 26a enters the second tilted state shown by the solid line in FIG. Judge whether or not. That is, it is determined whether or not an intention to shift down when the auxiliary brake is activated is displayed (S12). As a result, when the operation lever 26a of the operation switch 26 is not in the second tilted state shown by the solid line in FIG. 3, the automatic shift is performed when the shift map determination result passes through the upshift line shown in FIG. The ECU 18 shifts up the transmission 15 according to the shift map stored in the memory 18a (S15) and returns.

  On the contrary, when the operation lever 26a of the operation switch 26 is in the second tilted state shown by the solid line in FIG. 3, the automatic transmission ECU 18 then shifts up line stored in the memory 18a in the shift down control ECU 21. The amount of depression of the accelerator pedal 11 or the driver required torque when the vehicle has passed is compared with the current amount of depression of the accelerator pedal 11 or the driver requested torque (S13). If the current depression amount of the accelerator pedal 11 or the driver required torque is smaller than the depression amount of the accelerator pedal 11 or the driver required torque stored in the memory 18a, the shift-up of the transmission 15 is suspended (S16), Return. That is, in the state shown in FIG. 4 that has passed through the shift-up line and has not reached the shift-up line again, the shift-up of the transmission 15 is suspended (S16).

  Then, the accelerator pedal is depressed again from the state in which the shift-up is suspended, and the subsequent depression amount or driver required torque of the accelerator pedal 11 becomes the depression amount or driver required torque of the accelerator pedal 11 stored in the memory 18a. When it reaches again (T4 in FIG. 4), the suspension of the shift-up of the transmission 15 is released, the transmission 15 is shifted up (S15), and the process returns. That is, the transmission 15 is shifted up in a state where it passes through the shift up line and reaches the shift up line again as shown in FIG. 4 (S15).

  The control in the shift-down control ECU 21 as the shift-down control means and the control in the automatic disguise ECU 18 as the shift control means will be described in time series. As shown in FIG. 4, the vehicle travels when the accelerator pedal 11 is depressed. When the amount of depression of the accelerator pedal is reduced from the state, before the amount of depression becomes zero, it passes through a shift-up line for shifting up the transmission 15 of the shift map stored in the memory 18a (T1). . Then, the depression amount of the accelerator pedal 11 or the driver request torque at that time is stored in the memory 18a by the storage circuit 18b (S14). At the same time, the automatic disguise ECU 18 determines upshifting of the transmission 15 according to the shift map stored in the memory 18a. However, since the operation switch 26 is turned on and the amount of depression of the accelerator pedal 11 is reduced to zero from the traveling state in which the accelerator pedal 11 is depressed, the upshift is suspended (S16). ). For this reason, from the traveling state in which the accelerator pedal 11 is depressed, the depression amount of the accelerator pedal 11 is decreased, and the transmission 15 is shifted up until the depression amount of the accelerator pedal 11 becomes zero (T1 to T2). It will never be done.

  Thereafter, when the amount of depression of the accelerator pedal becomes zero (T2), the exhaust brake 13, which is an auxiliary brake, is operated, and at the same time, the transmission 15 is shifted down. Then, the shift speed of the transmission 15 in the state where the auxiliary brake is operated is lower than the shift speed of the transmission 15 in the traveling state before the depression amount of the accelerator pedal 11 is reduced. As a result, the braking force by the auxiliary brake can be reliably increased.

  Thereafter, when the accelerator pedal 11 is depressed (T3), the exhaust brake 13, which is an auxiliary brake, is deactivated, and the downshift control ECU 21 issues a command to the automatic transmission ECU 18, releases the downshift, and is downshifted. The transmission 15 that has been temporarily shifted up.

  Then, when the accelerator pedal 11 is further depressed and the amount of depression of the accelerator pedal or the driver requested torque becomes the amount of depression of the accelerator pedal or the driver requested torque for shifting up the transmission 15 stored in the memory 18a (T4). The suspension of the upshift is also released, and the transmission 15 is shifted up again by the automatic transmission ECU 18 which is a shift control means. As a result, when the auxiliary brake is deactivated (T3), the transmission 15 is prevented from being shifted up by the shift control means, and when the accelerator pedal is depressed from the state where the exhaust brake 13 is activated (T3). Upshifting over the two stages is avoided. As a result, the driver does not feel uncomfortable due to a significant decrease in the rotational speed of the engine 12 at a time.

  In the above-described embodiment, the single operation switch 26 is used as both the downshift switch for the exhaust brake 13 and the transmission 15. However, the operation switch for the exhaust brake 13 and the downshift in the transmission 15 are used. These operation switches may be provided separately.

  In the above-described embodiment, the case where the auxiliary brake is the exhaust brake 13 has been described. However, the auxiliary brake is not limited to the exhaust brake 13 as long as the auxiliary brake can assist the main brake device. For example, the auxiliary brake may be a retarder. Although not shown, the retarder is an electric braking device used for a large vehicle or the like. In a widely known form, a generator is provided that is connected to a propeller shaft for driving an axle and rotates, and a resistor is connected to the electrical output of the generator. When the retarder is operated to the braking state by operating the switch provided in the driver's seat, the output current of this generator flows to the resistor, the mechanical load on the propeller shaft increases, the vehicle enters the braking state, and the main brake device is It can help.

  Further, in the above-described embodiment, the shift-down control ECU 21 as the shift-down control means is formed independently and connected to the CAN 23, and the auxiliary brake ECU 14, the automatic transmission ECU 18, the engine ECU 19, the vehicle speed sensor 22, the accelerator sensor 24, and the operation. Although the case where communication with the switch 26 and the like can be performed has been described, the downshift control means for reducing the operating strength of the auxiliary brake may not be provided separately. For example, the auxiliary brake ECU 14, the automatic transmission ECU 18, and the engine ECU 19 may be provided with a circuit as a shift down control means.

10 Vehicle 11 Accelerator pedal 13 Exhaust brake (auxiliary brake)
15 Automatic transmission 18 Automatic transmission ECU (transmission control means)
18b Memory circuit (memory means)
21 Shift-down control ECU (shift-down control means)
26 Operation switch

Claims (2)

The transmission (15) and the transmission (15) are shifted up or down to shift the transmission (15) to a target shift stage determined from the depression amount of the accelerator pedal (11) or the driver required torque. A shift control means (18), an auxiliary brake (13) that can be operated when the amount of depression of the accelerator pedal (11) is zero, and the auxiliary brake (13) with the operation switch (26) turned on In a vehicle transmission device comprising a downshift control means (21) for downshifting the transmission (15) when operated.
The shift control means (18)
Suspend the shift up when the operation switch (26) is turned on and the accelerator pedal (11) is depressed and reduced to zero from the running state where the accelerator pedal (11) is depressed. A vehicle transmission characterized by the above. A memory for storing the amount of depression of the accelerator pedal (11) or the driver required torque that shifts up the transmission (15) by reducing the amount of depression of the accelerator pedal (11) from the running state in which the accelerator pedal (11) is depressed. Means (18b),
The speed change control means (18) is the amount of depression of the accelerator pedal (11) stored in the storage means (18b) or the amount of depression of the accelerator pedal (11) after the shift up is suspended or The transmission of a vehicle according to claim 1, wherein the suspension of the upshift is continued until the driver request torque is reached.

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