JPH0684138B2 - Shift control method for automatic transmission - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION <Field of Industrial Application> The present invention electronically controls a friction clutch interposed between an engine and a transmission via an actuator and switches a meshing position of the transmission to a gear position. The present invention relates to a shift control method for an automatic transmission that is electronically controlled via a means, and more particularly to an exhaust brake automatic deactivation control when a vehicle starts.

<Prior Art> In recent years, an automatic transmission that can automatically select a gear position according to a driving condition of a vehicle for the purpose of reducing a driver's burden of driving operation in a large freight vehicle, a shared vehicle, or the like. It is considered.

The conventional automatic transmission is mainly intended for small passenger cars, and a fluid coupling such as a torque converter is interposed between the engine and the planetary gear type transmission, and a planetary gear type using pressure oil as a control medium. Generally, the transmission is equipped with a gear position switching means.

<Problems to be solved by the invention> What is important in developing an automatic transmission for large-sized freight vehicles is that the number of vehicles produced is significantly smaller than that of passenger vehicles. The new design is extremely disadvantageous in terms of cost, and it is desirable to use the conventional drive system such as the friction clutch and the transmission including the conventional production equipment.

It is an object of the present invention to provide a shift control method for an automatic transmission that can automatically achieve a smooth shift operation by electronic control by using the conventional drive system as it is.

<Means for Solving Problems> A shift control method for an automatic transmission according to the present invention includes a friction clutch capable of connecting an output shaft of an engine and an input shaft of a transmission,
An actuator that engages and disengages the friction clutch, a shift speed instruction means that generates a shift speed signal corresponding to a shift speed selected by a shift lever, and a shift speed signal that is generated from the shift speed instruction device. An exhaust brake operation for selectively operating an exhaust brake, in a shift control method for an automatic transmission, comprising: a shift speed switching means for switching a shift speed; and a control device for controlling the operation of the actuator based on a running condition of a vehicle. It is characterized by comprising a device and a vehicle speed detecting means for detecting a vehicle speed, and when the vehicle speed detected by the vehicle speed detecting device is equal to or lower than a predetermined value, the exhaust brake is inactivated by the exhaust brake operating device.

<Operation> The friction clutch is operated by the control device via the actuator to transmit or cut off the driving force from the engine to the transmission. Further, the control device controls the operating characteristics of the actuator based on the traveling condition of the vehicle to transmit the driving force with less shift shock. On the other hand, when the driver selects a shift speed with the shift lever, a shift speed signal corresponding to the shift speed is output from the shift speed instruction means to the shift speed switching means, and the shift speed of the transmission is switched. Here, when the vehicle speed detected by the vehicle speed detecting means is equal to or lower than a predetermined value, even if the exhaust brake is selected to be operated by the driver, the exhaust brake is automatically deactivated by the exhaust brake operating device. Since it is maintained as desired, a smooth start and good fuel economy are realized.

<Embodiment> As shown in FIG. 1 showing the concept of an embodiment of an automatic transmission for implementing the method of the present invention, the automatic transmission is a diesel engine (hereinafter simply referred to as engine) 30 and its output shaft 30a. The gear type transmission 32 that receives the rotational force of the above through the friction clutch 31 is attached. The engine 30 has an input shaft 33 that rotates at half the speed of its output shaft 30a.
A fuel injection pump (hereinafter simply referred to as an injection pump) 34 equipped with is attached, an electromagnetic actuator 38 is connected to a control rack 35 of this pump 34, and an input shaft 33 of an output shaft 30a of the engine 30 An engine rotation sensor 39 that outputs a rotation speed signal is attached. The friction clutch 31 presses the clutch plate 41 against the flyhole 40 by well-known holding means (not shown), and when the air cylinder 42 as the clutch actuator shifts from the non-operating state to the operating state, the holding means operates in the releasing direction. And clutch 31
Changes from the connected state to the cutoff state (FIG. 1 shows the cutoff state). In addition, this clutch 31 is a clutch
Although the clutch stroke sensor 70 for detecting the disengaged state or the connected state of 31 by the clutch stroke is attached, a clutch touch sensor 43 may be attached instead. Further, the input shaft 44 of the gear type transmission 32 is provided with a clutch rotation speed sensor 45 which outputs a rotation speed (hereinafter, referred to as clutch rotation speed) signal of the input shaft 44. An air passage 47 is connected to the air chamber 46 of the air cylinder 42, and this is connected to an air tank 48 as a high pressure air source. An electromagnetic cut valve 49 as an opening / closing means for controlling the supply of operating air is installed in the middle of the air passage 47, and a duty-controlled normally closed solenoid valve 50 for opening the air chamber 46 to the atmosphere is further provided. Or installed. The air cylinder 42
The clutch stroke sensor 70 that outputs the clutch stroke amount is attached to the air tank 48, and the air sensor 72 that outputs an ON signal when the internal air pressure falls below a specified value is attached to the air tank 48. In order to switch the gear position of the gear type transmission 32 that achieves each shift speed, for example, the driver operates the change lever 54 to a shift position corresponding to a shift pattern as shown in FIG.
Based on the shift signal obtained by switching the shift stage selection switch 55, the gear shift unit 51 as the gear position switching means is operated to shift the gear position to the target shift stage corresponding to the shift pattern. Here, R indicates a reverse gear, N indicates a neutral gear, 1, 2 and 3 indicate respective designated gears, and D _P and D _E indicate arbitrary automatic gear positions from 2nd speed to 7th speed. , D _P , D _E ranges are selected, the second to seventh speeds are automatically determined based on the running conditions of the vehicle by the optimum shift stage determination process described later. As shown in FIG. 3 showing the shift range between the powerful automatic shift speed D _P and the economy automatic shift speed D _E , the second to seventh speeds in the D _E range indicated by the dotted line and the D _P range indicated by the solid line are shown. The gear shift timing of the high speed is set to the high speed side in the D _P range in order to cope with a high load of the vehicle. The gear shift unit 51 includes a plurality of solenoid valves (only one is shown in FIG. 1) 53 which are operated by an operation signal from the control unit 52,
The solenoid valve 53 has a pair of power cylinders (not shown) that are supplied with high-pressure operating air from the air tank 48 via these solenoid valves 53 to operate the select forks and shift forks (not shown) of the gear transmission 32. The power cylinders are operated in response to the given operation signals to change the meshing mode of the gear type transmission 32 in the order of select and seat. Further, the gear shift unit 51 is additionally provided with a gear position switch 56 as a gear position sensor for detecting each gear position, and a gear position signal from these gear position switches 56 is output to the control unit 52.
Further, a vehicle speed sensor 58 for emitting a vehicle speed signal is attached to the output shaft 57 of the gear type transmission 32, and further, the accelerator pedal 37 is caused to generate a resistance change as a voltage value according to the depression amount thereof,
An accelerator load sensor 60, which converts this into a digital signal by an A / D converter 59 and outputs the digital signal, is attached. break pedal
A brake sensor 62, which outputs a high-level brake signal when it is stepped on, is attached to 61, and a starter 63 which starts the engine 30 by meshing with the ring gear on the outer periphery of the flywheel 40 at a proper time is attached to the engine 30.
Is mounted and its starter relay 64 is connected to the control unit 52. Reference numeral 65 in the figure denotes a microcomputer that is attached to the vehicle separately from the control unit 52 to perform various controls of the vehicle, and controls the drive of the engine 30 by receiving input signals from each sensor (not shown). And so on. This microcomputer 65
Applies an actuation signal to the electromagnetic actuator 38 of the injection pump 34 to control the increase / decrease of the rotation speed of the output shaft 30a of the engine 30 (hereinafter, this is referred to as the engine rotation speed) by the fuel increase / decrease operation. The output signal as the engine speed increase / decrease signal can be received with priority over the depression amount of the accelerator pedal 37, and the engine speed is increased / decreased according to the output signal.

The control unit 52 is a microcomputer dedicated to the automatic transmission, and includes a microprocessor (hereinafter referred to as CPU) 66, a memory 67, and an interface 68 as an input signal processing circuit. The input port 69 of the interface 68 has a gear selection switch 55, a brake sensor 62, and an accelerator load sensor 60 described above.
An engine speed sensor 39, a clutch speed sensor 45, a gear position switch 56, a vehicle speed sensor 58 and a clutch sensor 43.
Output signals are input from the clutch stroke sensor 70 and the air sensor 72 (used to detect the disengaged state or the connected state of the friction clutch 31 instead of the clutch stroke sensor 70). On the other hand, the output port 74 is the microcomputer 65, the starter relay 64 and the solenoid valve described above.
Output signals can be sent to 50, 53 and cut valve 49 by connecting them respectively. In the figure, reference numeral 75 is an air tank.
When the air pressure of 48 does not reach the set value, it is an air warning lamp that lights up by receiving output from a drive circuit (not shown) .76 receives output when the friction amount of the friction clutch 31 exceeds a specified value. It is a clutch warning lamp that lights up.

The memory 67 is composed of a read-only ROM in which programs and data shown in the flowcharts of FIGS. 5 to 8 are written and a read / write RAM. That is, in the ROM, the duty ratio α of the solenoid valve 50 corresponding to the value of the accelerator load signal is stored in advance in the ROM as a map as shown in FIG. Read the value. The gear selection switch 55 described above
Outputs a select signal and a shift signal as a shift signal. A gear stage device corresponding to a pair of these two signals is stored in advance as a data map, and when the select signal and the shift signal are received, Refer to the map and output the corresponding output signal to each solenoid valve of the gear shift unit 51.
Output to 53 and adjust the gear position to the target gear position corresponding to the gear shift signal. In this case, the gear position signal from the gear position switch 56 is output upon completion of the shift, and it is determined whether or not all gear position signals corresponding to the select signal and the shift signal have been output, and a signal indicating whether the meshing is normal or abnormal. Used to emit. Further, the ROM also stores a map for determining the optimum shift speed based on the vehicle speed and accelerator load signals when the target shift speed is present in the D _P range or D _E range.

Here, the shift control procedure of the present embodiment will be described with reference to FIGS.

As shown in FIGS. 5 (a) and 5 (b), when the program starts, the control unit 52 enters the starting process,
After the completion of the starting process, the vehicle speed signal is input, and if the value is equal to or less than the specified value (for example, 0 km / h to 3 km / h), the start process is performed, and if the value is equal to or more than the specified value, the shift process is performed. However, if the engine speed N _E before the start process is calculated by calculating the engine speed N _E is less than or equal to a specified value (for example, idle speed), it is determined whether the oil pump is stopped. The engine is stopped and the starting process is performed again. When the oil pump is not stopped or when the engine speed N _E exceeds the specified value, it is determined whether or not the starting process is being performed. If the starting process is not being performed, the accelerator depression amount (hereinafter, This is referred to as an accelerator load signal) is compared with a specified value to determine whether or not the driver intends to start. During the starting process and when the accelerator load signal is equal to or higher than a specified value, the engine speed N _E and the first engine stop (hereinafter, simply referred to as engine stall)
Compared to prevent rotation speed N _EST1, if the engine speed N _E is less than the first engine stall prevention rotation speed N _EST1 friction Suratchi 31
Turn off and start processing. On the other hand, compares the engine speed N _E and the higher than first engine stall prevention rotation speed N _EST1 second engine stall prevention rotation speed N _EST2 when the accelerator load signal is below the prescribed value, the engine speed N _{E Is} below the second engine stall prevention speed N _EST2 , the clutch is disengaged and the start processing is performed.If the engine speed N _E exceeds the second engine stall prevention speed N _EST2 or the engine speed N _E is the If the engine stall prevention speed N _EST1 is exceeded, start processing is started.

In the starting process shown in FIG. 6, a signal of the engine speed N _E is input, it is determined whether the value is within the stop range of the engine 30, and if the engine 30 is stopped, a clutch connection signal is output and After taking a time lag, the friction clutch 31 is connected under the normal pressure and the normal condition. When the friction clutch 31 is connected under the normal pressure and in the normal state, the friction clutch 31 is disengaged from this position to some extent, and the drive wheels of the vehicle shift from the rotating state to the stop state. Are described as points) according to the wear state of the facing of the friction clutch 31 and the presence / absence of a load. In other words, the stroke of the clutch plate 41 from the LE point until the friction clutch 31 is completely engaged is almost constant, and the friction clutch 31 can be smoothly engaged regardless of the vehicle condition. When the LE point is corrected, whether or not the position of the change lever 54 and the gear position are the same, that is, the gear shift signal and the gear position signal are the same, and the target gear position (D _E When the D _P range is selected, it is determined whether the gear position of the gear type transmission 32 is aligned in advance (for example, the second speed is set in advance). If the position of the change lever 54 and the gear position are different, it is determined whether the air in the air tank 48, which is the main tank, has reached the specified pressure, and if the specified pressure is reached, the friction clutch 31 is turned on. Turn off and operate the actuator (not shown) with the air in the air tank 48 to automatically match the gear position with the position of the change lever 54, connect the friction clutch 31, and connect the air tank 48, which is the main tank, to the sub tank (not shown). After turning off the switching solenoid valve of, the judgment is again made as to whether or not the position of the change lever 54 and the gear position are the same.
If the air in the air tank 48 has not reached the specified pressure, it is determined whether the air in the sub-tank has reached the specified pressure, and if it has reached the specified pressure, the switching solenoid valve is turned on.
The friction clutch 31 is turned on to disengage, and the power cylinder is operated by the air in the sub-tank to automatically select the gear position corresponding to the position of the change lever 54. When the air in the sub tank has not reached the specified pressure, the air warning lamp 75 is turned on to notify the driver that the air in the air tank 48 and the air in the sub tank are below the specified pressure. on the other hand,
When the position of the change lever 54 is the same, a relay for enabling the starter is output. When the starter enabling relay is output, the starter 63 can be started and the engine 30 can be started.Therefore, it is determined whether the engine 30 has started.If the engine 30 starts, the starter enabling relay is OF
When it is set to F and the engine 30 does not start, it is determined again whether or not the position of the change lever 54 and the gear position are the same. When the starter enable relay is turned off, it checks whether the air in the air tank 48 and sub tank has reached the specified pressure.If it does not reach the specified pressure, turn on the air warning lamp 75 and turn on the air. The judgment is repeated until the pressure reaches the specified pressure, and when the specified pressure is reached, the air warning lamp 75 is turned off and the starting process is completed.

After the completion of the starting process, the vehicle speed signal is read, and if it is below the specified value, the starting process is started. As shown in FIGS. 7A and 7B, the CPU 66 first outputs an ON signal to the cut valve 49 to disengage the friction clutch 31, and disengages the friction clutch 31. At the same time, the relay that releases the operating state of the exhaust brake device (exhaust brake) (inactive state) is turned on.
When the vehicle speed is equal to or lower than the predetermined value, the exhaust brake is not applied even if the operation switch for operating the exhaust brake is turned on. Next, change lever
It is determined whether the position of 54 and the gear position are the same, and if NO, the gear position is adjusted to the target conversion stage. In this case as well, the exhaust release relay is turned on in order to deal with the repetition from the subsequent flow. When the position of the change lever 54 and the gear position become the same, it is judged again whether the vehicle speed is lower than the specified value, and the vehicle speed exceeds the specified value.
In the case of NO, the process proceeds to the accelerator load signal detection step described later. On the other hand, if it is not, whether or not the gear position which has reached the target shift speed is neutral is read from the shift signal, and if YES, the LE point is corrected again. If the gear position is NO other than neutral, set the friction clutch 31 to LE
Connected up to the point. Next, it is determined whether or not the accelerator load signal value exceeds a specified value (a voltage that is low enough to indicate the driver's intention to start), and in the case of NO in which it is determined that the driver does not have the intention to start, the above steps are performed. Repeat. On the other hand, in the case of YES where it is determined that there is a will to start, the exhaust release relay is turned on.
Set to FF, and set the normal state where the exhaust brake device operates according to the ON operation of the operation switch of the exhaust brake.
Therefore, the gear position of the gear type transmission 32 is in a state in which the vehicle can be started and the operation switch of the exhaust brake is ON, such as when the vehicle is stopped while the exhaust brake is being applied and the vehicle is on standby for restarting. Even in this case, since the exhaust brake device is automatically kept in the inoperative state until the accelerator depression amount exceeds a certain specified value, a smooth start and good fuel economy are realized.

At the same time, the accelerator load signal value is detected, and the optimum duty ratio α corresponding to this value is read from the map of FIG. Then, the obtained pulse signal of the optimum duty ratio α is output to the solenoid valve 50, and the friction slatch 31 is gradually connected. At this time, the CPU 66 outputs a selection signal to the input port 69 so as to continue inputting the signal of the engine speed N _E , and the engine speed N _E over time based on the signal of the engine speed N _E is stored in the memory 67. Is sequentially stored in the RAM, and arithmetic processing is performed to obtain the peak point M, and the peak point M is detected, as shown in FIG. 9 showing an example of changes in the engine speed N _E and the clutch speed N _CL . Until NO
Proceed to and repeat from the accelerator load signal detection step.
On the other hand, when the peak point M is detected solenoid valve than at the T ₁ 50
Is held ON. The peak point M occurs because the rotation of the output shaft 30a of the engine 30 decreases as the rotation of the input shaft 44 of the gear transmission 32 via the friction clutch 31 starts to transmit power to the drive wheels. Is.

Next, the LEOFF routine is executed. This LEOFF routine deals with the case where the vehicle is slightly moved with the half clutch instead of the normal start. In the LEOFF routine, it is first determined whether the vehicle speed is higher than the specified value, and the vehicle speed is higher than the specified value. In the case of YES, it is determined that the vehicle has started normally, and the LEOFF routine ends, and the process returns to this starting flow.
On the other hand, in the case of NO, it is judged next whether or not the accelerator pedal 37 is depressed, and in the case of YES, the LEOFF routine is similarly ended, and in the case of NO, it is continued by the off duty until the LE point is reached. Disengage the friction clutch 31 gradually. During this time, it is also determined whether or not the accelerator pedal 37 is depressed, and when the accelerator pedal 37 is depressed, the process returns to the accelerator load signal detection step described above. After the friction clutch 31 has retracted to the LE point, the process returns to the step of determining the position of the change lever 54 and the gear position.

When the LEOFF routine ends and it is determined that the vehicle is starting normally,
The friction clutch 31 is connected from the half clutch state at the LE point to the clutch meet. At this time, the engine speed N _E after passing the peak point M corresponds to the rotation of the input shaft 44 of the gear transmission 32. Considering that the engine speed N _E gradually decreases as the engine speed N _CL increases, the engine speed N _E is controlled so that the rate of decrease falls within a predetermined range and the starting shock is reduced. That is, first, it is determined whether or not the engine speed reduction rate ΔN _{E for} each predetermined time is less than or equal to the first set value | x ₁ | shown in FIG. If YES, after executing the LEOFF routine described above, the accelerator load signal is detected again and the optimum duty ratio α corresponding to this value is determined.
The friction clutch 31 is gradually connected by. After this, the engine speed decrease rate ΔN _E becomes the second set value | x ₂ | (| x ₁ | <| x ₂ |)
If it is NO, if NO, the process returns to the step before the LEOFF routine described above, and the loop for keeping the engine rotation reduction rate ΔN _E constant is repeated. On the other hand, the engine speed decrease rate ΔN _E is | x ₁ |
If it is larger, it is determined whether or not the engine rotation reduction rate ΔN _E is equal to or greater than the third set value | y ₂ | (| x ₂ | <| y ₂ |). If YES here, after executing the LEOFF routine, the friction clutch 31 is gradually disengaged by off duty. After that, the engine rotation reduction rate ΔN _E is the fourth set value | y ₁ | (| y ₁ |
<| Y ₂ |) It is judged whether it is less than or equal to, and if it is NO, the friction clutch
Repeat the loop that shuts off 31. YES or if or when the rotation drop rate .DELTA.N _E of the aforementioned engine | y ₂ | NO in the following whether the determination step, the engine rotational speed decrease rate .DELTA.N _E
If it is YES in the determination step of whether or not | x ₂ | or more, at this point the engine rotation reduction rate ΔN _E falls substantially within the shaded region in FIG. 10. Therefore, the condition for switching the friction clutch 31 to the connected state without starting shock due to the half-clutch state and without excessively prolonging the starting time has been established, so that the air pressure of the friction clutch 31 is held at the current state. To do. After that, the CPU 66 determines that the difference between the engine rotation reduction rate ΔN _E and the clutch rotation speed N _CL is a specified value (for example, |
N _E −N _CL | = about 10 rpm) or less. If NO, the above loop is repeated, and after a predetermined time lag at T ₂ when YES, the solenoid valve 50 is turned on. Fully open and clutch meet. After this, after a predetermined time lag on condition that the engine speed N _E is equal to or higher than the idle speed, the CPU 66 determines that the slip ratio of the friction clutch 31 (the difference between the engine speed N _E and the clutch speed N _CL is / Engine speed N _E ) is calculated and this value is compared with the specified value,
If it is less than the specified value, the process returns to the main flow. On the other hand, when the slip ratio is equal to or more than the specified value, it is determined that the wear amount of the friction clutch 31 is large, and an ON signal as a clutch wear signal is output to the clutch warning lamp 76 as an output port 74 and a drive circuit (not shown). To output the clutch warning lamp 76.

After the completion of the start-up process, the CPU 66 reads the vehicle speed signal, and if it exceeds the specified value, the shift process is started. As shown in FIGS. 8A and 8B, first, the input port 69
A selection signal is given to the to check whether or not there is a brake failure. If YES in the case of a brake failure, the gears are downshifted by one step to stop the vehicle as described later. On the other hand, when the brake fail is NO, it is checked whether or not the brake is being suddenly braked with a deceleration of a certain value or more by using, for example, an acceleration sensor, and if YES, a shift operation described later is performed. Since the braking distance becomes long, the main flow is returned to and the shifting operation is temporarily stopped. However, if the friction clutch 31 is disengaged even when the brakes are suddenly applied, it is determined that the gear shift is in progress, so the gear shift operation is completed and the friction clutch 31 is engaged.

On the other hand, when there is no sudden braking operation, or when the friction clutch 31 is disengaged as described above even during sudden braking, the position of the change lever 54 is read, and this is D _P , D _E
Other than the above, it is judged whether it is the designated gear stage of 1, 2, or 3 or the automatic gear stage of D _P , D _E , the R stage, or the N stage.

In the case of the designated gears of 1, 2, and 3, it is determined whether or not the position of the change lever 54 and the gear position are the same, YES is returned to the main flow, and NO is advanced to the next step. In this step, the change lever 54
Is positioned, and it is determined whether or not the current gear position before the shift is in the D _P , D _E range and corresponds to the shift down from here. If YES, it is determined whether or not the engine 30 can be downshifted without overlining the rotation, and if NO, proceed to the next step to warn the driver of the overrun by the reverse warning buzzer,
Return to the main flow without performing gear shifting operation. When the determination as to whether or not the overrun is performed is YES, the downshift operation is performed by one step from the current gear position as follows. As shown in FIG. 11 showing the concept of this downshift operation,
A control signal of the control rack 35 is output to the electromagnetic actuator 38 via the output port 74 and the microcomputer 65, and the engine speed N _E is held as it is. Then, the ON signal is output to the cut valve 49 for a predetermined time through the output port 74 to output the friction clutch 31.
The control signal is output to each solenoid valve 53 of the gear shift unit 51 to downshift to a gear position one step lower than the gear position before shifting. Then, the electromagnetic actuator 38 is output through the output port 74 and the microcomputer 65.
A voltage signal that causes the same rotation as the clutch circuit number N _CL that increases the engine speed N _E is output as an accelerator pseudo signal to match the clutch circuit number N _CL after the shift with the engine speed N _E. The air is removed from the air cylinder 42 to move the friction clutch 31 to the half clutch state at the LE point.
Then, the friction clutch 31 is connected at the optimum duty ratio α corresponding to the accelerator load signal, and the difference between the engine speed N _E and the clutch circuit number N _CL is compared with a specified value preset for each gear stage. Then, the connecting operation of the friction clutch 31 with the above duty ratio α is repeated until | N _E −N _CL | becomes equal to or less than the specified value. Then, after | N _E −N _CL | becomes equal to or less than the specified value, the clutch connection signal is output to complete the connection of the friction clutch 31 with a time lag of a predetermined time, and the accelerator pseudo signal is released to release the main flow. Return to. When the number of clutch circuits N _CL falls below the specified value in the above operation, it is assumed that the vehicle speed is low and the friction clutch 31 is not connected to the connector 1 in FIG. 5 (a). Go to LE point correction.

On the other hand, as a result of the determination as to whether or not the shift down from the D _P and D _E ranges is made, if NO, it is determined whether or not the shift is up. Then, if this is YES, the shift up operation is performed as follows and the process returns to the main flow. As shown in FIG. 12 showing the concept of this shift-up operation, the output port 74 and the microcomputer 65 are provided.
Control rack 35 to electromagnetic actuator 38 via
The control signal of is output and the engine speed N _E is returned to the idle speed. Then, after disengaging the friction clutch 31, the gear position is output to each solenoid valve 53 via the output port 74 so as to match the target gear position which is one of 1, 2 and 3 as the designated gear position. To do. After that, the operation after the accelerator pseudo signal output of the downshift operation is performed to match the engine speed N _E with the clutch speed N _CL after shifting, and the connection of the friction clutch 31 is completed to complete the main operation. Return to flow.
If the result of the above determination as to whether or not the shift is up is NO, then it is determined whether or not the vehicle is in overrun and this is YES.
In the case of, the engine speed N _E is held as it is, the friction clutch 31 is disengaged, and the gear position is adjusted to one of the specified gear positions 1, 2 and 3 and the downshift is performed. Perform the operation after outputting the accelerator pseudo signal of the operation and return to the main flow. If the result of the determination as to whether or not the vehicle is in the overrun is NO, a warning is given by the warning buzzer.

The above operation is performed when the position of the change lever 54 is determined and the specified gear position is 1, 2, or 3, but the result of the determination of the position of the change lever 54 is D _P , If it is at the automatic gear position of D _E , the following operation is performed. That is, the vehicle speed and the amount of depression of the accelerator pedal 37 are detected, and it is determined whether the change lever 54 is in the D _P range or the D _E range, and D _P or Determines the optimum shift speed considered to be the target high speed in each range of D _E. After this, it is judged whether or not the gear position matches the optimum high speed stage, and if YES, the process returns to the main flow, and if NO, shifts to the upshift step and shifts to the same shift as above. The operation is performed.

If the result of the determination of the position of the change lever 54 is the R stage, the CPU 66 determines whether or not the gear position matches the R stage as the target shift stage, and the reverse operation is currently being performed.
If YES, the flow returns to the main flow, and if NO, which is an erroneous operation, the engine speed N _{E is set} to idle rotation and the friction clutch 31 is disengaged in the same manner as described above. Then, in order to return the gear position to neutral, output to each solenoid valve 53 via the output port 74, turn on the reverse warning lamp indicating the shift error, then connect the friction clutch 31 and return to the main flow. .

Further, when the result of the determination of the position of the change lever 54 is N steps, whether or not the change lever 54 has moved within a predetermined time, that is, only the N steps have been passed during the shift operation by the driver. Determine if there is no. As a result of this judgment,
If YES in the middle of the shift operation, as described above, the position of the change lever 54 and the gear position are determined, and the process returns to the main flow, or shifts up and down to return to the main flow. That operation is done. However, if NO is selected for the N stage, the engine speed N _E is reduced to idling and the friction clutch
After disconnecting 31 to set the gear position to neutral, the friction clutch 31 is connected again and the flow returns to the main flow.

In this embodiment, the air pressure from the air tank 48 provided in the vehicle is used to drive the air cylinder 42 for operating the friction clutch 31, but it is also possible to use hydraulic pressure as the control medium. However, in this case, a hydraulic pressure generation source such as an oil pump must be newly added, which may increase the cost. Further, it goes without saying that the shift control procedure, the shift pattern and the like shown in the present embodiment can be appropriately changed in small places as necessary, and the present invention is also applied to a vehicle equipped with a gasoline engine. be able to. Further, the clutch pedal may be mounted as a dummy for a driver who changes trains from the manual transmission,
In this case, it is possible to set the R gear and the designated gears of 1, 2, and 3 so that the clutch pedal and the air cylinder 42 are prioritized to function.

<Effects of the Invention> According to the shift control method of the automatic transmission of the present invention, the drive system such as a general friction clutch or transmission is used as it is, and the actuator of the friction clutch or the gear shift means is operated to perform the shift operation. Since this is done, it is possible to obtain a low-cost automatic transmission without significantly modifying the conventional vehicle production equipment. Also, when the vehicle speed is under a certain value, even if the exhaust brake is selected to be activated by the driver, the exhaust brake is automatically deactivated, so exhaust gas emission is suppressed. Therefore, it is possible to achieve a smooth start and good fuel efficiency.

[Brief description of drawings]

FIG. 1 is a schematic configuration diagram of an automatic transmission according to an embodiment of the present invention, FIG. 2 is a conceptual diagram showing an example of a shift pattern thereof, and FIG. 3 is a shift characteristic of the D _P range and D _E range. FIG. 4 is a graph showing an example of a map for determining the duty ratio, and FIGS. 5 (a) and 5 (b)
8 (a) and 8 (b) are a flow chart showing an example of the control program, and FIG. 9 is a graph showing an example of changes with time of the engine speed and the clutch speed during the shift.
Fig. 10 is a graph showing the region of the rate of change of the engine speed during the shift, Fig. 11 is a conceptual diagram of the operation during downshift operation,
FIG. 12 is a conceptual diagram of an operation during a shift-up operation. In the drawing, 30 is an engine, 30a is an output shaft of the engine, 31 is a friction clutch, 32 is a gear type transmission, 34 is a fuel injection pump, 35 is a control rack, 37 is an accelerator pedal, 38 is an electromagnetic actuator, and 42 is an air. A cylinder, 44 is an input shaft of a gear type transmission, 48 is an air tank, 50 is a solenoid valve, 51 is a gear shift unit, 52 is a control unit, 54 is a change lever, and 65 is a microcomputer.

Front page continuation (72) Inventor Shigeki Fukushima 4-21-1, Shimomaruko, Ota-ku, Tokyo Mitsubishi Motors Corporation Maruko factory, Tokyo Motor Manufacturing Co., Ltd. (56) Reference JP-A-60-252829 (JP, A)

Claims (1)

[Claims] 1. A friction clutch capable of connecting an output shaft of an engine and an input shaft of a transmission, an actuator for connecting and disconnecting the friction clutch, and a shift speed signal corresponding to a shift speed selected by a shift lever. A gear shift stage instruction means, a shift stage shift means for switching the shift stage of the transmission upon receiving a shift stage signal generated from the shift stage command means, and a control device for controlling the operation of the actuator based on the traveling condition of the vehicle. And a vehicle speed detecting means for detecting a vehicle speed, wherein the vehicle speed detected by the vehicle speed detecting apparatus is a predetermined value. A shift control method for an automatic transmission, characterized in that the exhaust brake is deactivated by the exhaust brake operating device in the following cases.