JPS61220939A - Speed-change control of automatic transmission - Google Patents

Abstract

PURPOSE:To prevent the inutile speed change by obtaining the traveling resistance from the driving force at present which is calculated on the basis of the detection value of the control-rack position of a fuel injector and the acceleration force and suppressing the speed change operation when the traveling resistance force exceeds the effective driving force at the next stage. CONSTITUTION:In an automatic transmission, a frictional clutch 31 which connects and disconnects the output shaft 30a of an engine 30 and the input shaft 44 of a gear type transmission 32 is operation-controlled by an air cylinder 42, and the gear position of the gear type transmission 32 is switching-controlled by a gear shift unit 51. When the gear position is switched to the high-speed stage side, when such automatic transmission is controlled by the gear shift unit 51, the traveling resistance is obtained from the driving force at present which is calculated from the output of the stroke position detecting means (abbreviated in the figure) of the control rack 35 of a fuel injection pump 34 and the acceleration force calculated from the acceleration speed at present. If the traveling resistance exceeds the effective driving force at the next stage, speed change operation is suppressed.

Description

[Detailed Description of the Invention] <Industrial Application Field> The present invention electronically controls a friction clutch interposed between an engine and a transmission via an actuator, and also changes the gear position of the transmission. The present invention relates to a speed change control method for an automatic transmission that is electronically controlled via means.

<Conventional technology> In recent years, automatic transmission devices that can automatically select the gear position according to the driving conditions of the vehicle have been developed in order to reduce the burden of driving operations on the driver of large freight vehicles, passenger cars, etc. It is considered.

Conventional automatic transmissions are aimed exclusively at small passenger cars, and have a fluid coupling such as a torque converter interposed between the engine and the planetary gear transmission, and use pressure oil as the control medium. ! The gear position switching means of a gear type transmission is generally of a round type.

<Problems to be solved by the invention> In developing automatic transmission devices for large freight vehicles, etc., it is important to avoid expensive torque converters, etc., since the number of vehicles produced is significantly smaller than that of passenger cars. Designing a new one is extremely disadvantageous in terms of cost, and it is desirable to use the existing drive system, including friction clutches and transmissions, as is, including existing production equipment.

Based on this knowledge, it is an object of the present invention to provide a speed change control method for an automatic transmission device that can automatically achieve smooth speed change operations through electronic control using a conventional drive system as is.

Means for Solving the Problems> The speed change control method for an automatic transmission according to the present invention includes a friction clutch connected to the output shaft of an engine, a gear type transmission connected to a clutch actuator for operating the friction clutch, Gear position switching means for switching the gear position of the gear type transmission;
In an automatic transmission equipped with a control device that controls the operation of the clutch actuator and the gear position switching means based on the driver's intention and vehicle running conditions, fuel injection is performed when switching the gear position to a high speed gear. The stroke position of the control rack of the device is detected, the current driving force is calculated based on the stroke position of the control rack, the current acceleration is detected, the acceleration force is calculated based on this acceleration, and the acceleration force and the current driving force are calculated. This is characterized in that running resistance is determined from the driving force, and if this running resistance exceeds the effective driving force of the next stage, no gear change operation is performed.

Function> The friction clutch is operated by the control device via the clutch actuator, and the transmission of driving force from the engine to the gear type transmission is interrupted. Further, the control device controls the operating characteristics of the clutch actuator to transmit the driving force with less shift shock, and the control device operates the gear position switching means in conjunction with the operation of the friction clutch.
The optimum gear position is automatically selected. This speed change operation is performed based on the driver's will and preset vehicle driving conditions.

On the other hand, when the vehicle is running uphill and the gear position is changed to the high speed side, the stroke position of the control rack of the fuel injection device and the acceleration force of the vehicle at this time are detected to calculate the running resistance. If this exceeds the effective driving force in the next stage, the gear position will not be changed to the high speed stage.

Embodiment Example As shown in FIG. 1, which shows the concept of an embodiment of an automatic transmission device that implements the method of the present invention, this automatic transmission device includes a diesel engine (hereinafter simply referred to as engine) 30 and its output shaft. 30a via a friction clutch 31.

The engine 30 has a fuel injection pump (
An accelerator pedal 37 and an electromagnetic actuator 38 are connected to the control rack 35 of the pump 34 via a link 36, and an electromagnetic actuator 38 is connected to the input shaft 33. An engine rotation sensor 39 that generates a rotational speed signal of the output shaft 30a of the engine 30 is attached, and a rack position sensor 77 that generates a rack position signal is attached to the control rack 35. In the friction clutch 31, a clutch plate 41 is brought into pressure contact with the flywheel 4o by a well-known clamping means (not shown), and when the air cylinder 42 as a clutch actuator shifts from a non-operating state to an operating state, the clamping means operates in the releasing direction. Then, the clutch 31 changes from the connected state to the disconnected state (FIG. 1 shows the disconnected state). Although a clutch air sensor 70 is attached to this clutch 31 to detect the disconnected state or connected state of the clutch 31 by 0N10FF operation, a clutch touch sensor 43 may be attached instead. Further, a clutch rotation speed sensor 45 is attached to the input shaft 44 of the gear type transmission 32 to generate a signal of the rotation speed of the input shaft 44 (hereinafter referred to as clutch rotation speed). The air chamber 46 of the air cylinder 42 has an air passage 4.
7 is connected, and this is the air tank 48 as a high pressure air source.
is connected to. In the middle of the air passage 47, there is an electromagnetic cut valve 4 as an opening/closing means for controlling the supply of working air.
9 is attached, and a duty-controlled always-closed solenoid valve 50 for opening the air chamber 46 to the atmosphere is also attached. The air cylinder 42 is equipped with the aforementioned clutch air sensor 70 that outputs an ON signal when the internal air pressure exceeds a specified value that causes the clutch 31 to be disengaged, and the air tank 48 is further equipped with the clutch air sensor 70 that outputs an ON signal when the internal air pressure exceeds a specified value that causes the clutch 31 to be disengaged. An air sensor 72 is attached that outputs an ON signal when the condition is reached. Gear type transmission 32 for achieving each gear stage
To change the gear position, move the change lever 5 to the gear position corresponding to the shift pattern shown in FIG.
4, the driver operates the gear shift unit 51 as a gear position switching means based on the shift signal obtained by switching the gear selection switch 55, and switches the gear position to the target gear corresponding to the shift pattern. That's what I do. Here, R indicates reverse gear, N is neutral, 1.2.3 indicates each designated gear, and D
P and D indicate arbitrary automatic gears from 2nd to 7th gears, and when the DP or DF range is selected, the 2nd to 7th gears are selected based on the vehicle driving conditions by the optimum gear determination process described later. Determined automatically. In addition, as shown in FIG. 3, which shows the shift range between Dp, which is a powerful automatic gear, and DE, which is an economy automatic gear, the shift timings of 2nd to 7th speeds in the λ range, which is represented by a dotted line, and the DP range, which is represented by a solid line, are shown in FIG. The DP range is set to the higher speed side in order to deal with situations such as when the vehicle is under high load. The gear shift unit 51 includes a plurality of electromagnetic valves (only one is shown in FIG. 1) 5 that are actuated by an actuation signal from a control unit 52.
3, and a pair of power cylinders (not shown) to which high-pressure operating air is supplied from the air tank 48 via the electromagnetic valves 53 to operate the select forks and shift forks (not shown) of the gear type transmission 32. Valve 5
The power cylinders are operated in accordance with the operation signals given to the gear transmissions 32 and 3, respectively, and are operated to change the meshing mode of the gear type transmission 32 in the order of select and shift. Further, the gear shift unit 51 is provided with gear position switches 56 as gear position sensors that detect the positions of each gear, and gear position signals from these gear position switches 56 are output to the control unit 52. Further, a vehicle speed sensor 58 is attached to the output shaft 57 of the gear type transmission 32, and outputs a vehicle speed signal.
Furthermore, an accelerator load sensor 60 is attached to the accelerator pedal 37. The accelerator load sensor 60 generates a resistance change as a voltage value according to the amount of pedal depression, converts this into a digital signal by an A/D converter 59, and outputs the signal. A brake sensor 62 is attached to the brake pedal 61 that outputs a high-level brake signal when the brake pedal 61 is depressed, and a starter 63 is attached to the engine 30 to start the engine 30 by meshing with a ring gear on the outer periphery of the flywheel 40 at the appropriate time.
is installed, and its starter relay 64 is connected to the control unit 52. In addition, the code in the figure is 6.
Reference numeral 5 designates a microcomputer that is attached to the vehicle separately from the control unit 52 and performs various controls of the vehicle, and receives input signals from various sensors (not shown) to perform drive control of the engine 30, etc. This microcomputer 65 controls the electromagnetic actuator 3 of the injection pump 34.
8, the engine 30 is activated by increasing or decreasing fuel.
The rotational speed of the output shaft 30a (hereinafter referred to as engine rotational speed) can be controlled to increase or decrease, but the output signal from the control unit 52 as an engine rotational increase/decrease signal can be controlled by
The amount of depression of the accelerator pedal 37 via the link 36 can be received preferentially, and the engine speed is increased or decreased in accordance with this output signal.

The control unit 52 is a microcomputer dedicated to the automatic transmission, and is composed of a microprocessor (hereinafter referred to as CPU) 66, a memory 67, and an interface 68 as an input signal processing circuit.

The input hole 69 of the interface 68 includes the gear selection switch 55, the brake sensor 62, the accelerator load sensor 60, the engine rotation sensor 39, the clutch rotation speed sensor 58, and the clutch touch sensor 43. Output signals are input from the clutch air sensor 70 and the air sensor 72 (used when detecting the connection state in place of the clutch air sensor 70). On the other hand, the output boat 74 includes the above-mentioned microcomputer 65, starter relay 64, and solenoid valve 5.
0.53 and the cut valve 49, and output signals can be sent to these. In addition, the reference numeral 75 in the figure is an air warning lamp that lights up upon receiving an output from a drive circuit (not shown) when the air pressure in the air tank 48 does not reach a set value, and 76 is an air warning lamp that lights up when the amount of wear of the friction clutch 31 is specified. This is a clutch warning lamp that lights up in response to the output when the value is exceeded.

The memory 67 is a read-only ROM in which programs and data shown in flowcharts in FIGS. 5 to 8 are written.
It consists of a RAM that can be used for both reading and writing. That is,
In addition to the above program, the duty rate α of the solenoid valve 50 corresponding to the value of the accelerator load signal is previously stored in the ROM as a map as shown in FIG. read out. The gear selection switch 55 described above outputs a select signal and a shift signal as a gear change signal, but the gear position corresponding to a pair of combinations of these signals is stored in advance as a data map, and the select signal and shift signal are stored in advance. When receiving the map, the corresponding output signal is outputted to each solenoid valve 53 of the gear shift unit 51 with reference to this map, and the gear position is adjusted 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 when the gear shift is completed, and it is determined whether the gear position signals corresponding to the select signal and the shift signal are all output, and whether the meshing is normal or abnormal. It is used to emit a signal. Furthermore, the ROM also stores a map for determining the optimum gear position based on vehicle speed, accelerator load, and engine rotation signals when a target gear position exists in the DP range or home range.

Here, the speed change control procedure of this embodiment will be explained based on FIGS. 5 to 8.

As shown in FIGS. 5(a) and 5(b), when the program starts, the control unit 52 enters the starting process, and after the starting process is completed, inputs a vehicle speed signal, and sets the value to a specified value (for example, Ok+Jh to 3 kIl). /h) or less, the start process is performed, and if the value is above the specified value, the gear change process is performed. However, if the engine speed NE is below the specified value (for example, idle speed) before calculating the engine speed N6 and performing the start processing, the oil pump will determine whether or not it has stopped, and if it has stopped, the engine will stop. It is assumed that this is the case and the startup process is performed again.

If the oil pump is not stopped or the engine speed exceeds the specified value, it is determined whether or not the start process is in progress, and if the start process is not in progress, the amount of accelerator depression (hereinafter referred to as an accelerator load signal) is compared with a specified value to determine whether or not the driver intends to start the vehicle. During the start processing and when the accelerator load signal is below a specified value, the engine rotation speed NE is compared with the first engine stop (hereinafter simply referred to as engine stall) prevention rotation speed NEs□, and the engine rotation speed N[: If the first engine stall prevention rotation speed is NES, then the friction clutch 31 is disengaged and the start process is performed. On the other hand, if the accelerator load signal exceeds the specified value, a second engine stall prevention rotation speed Nl higher than the engine rotation speed NE & the first engine stall prevention rotation speed N:
S1°, and if the engine speed N6 is less than the second engine stall prevention rotation speed NEST2, the clutch is disengaged and the start process is performed, and if the engine speed NE exceeds the second engine stall prevention rotation speed NEsT2, When the engine speed N exceeds the first engine stall prevention speed limit, □, the process moves to a start process.

In the starting process shown in FIG. 6, a signal of the engine rotation speed N is input, and it is determined whether the value is within the stop range of the engine 30. If the engine 30 is stopped, a clutch connection signal is output and a time lag is detected. , and connect the *t* clutch 31 at the normal pressure and in the normal state.

When the friction clutch 31 is connected with the normal pressure and in the normal state, the friction clutch 31 is disengaged to some extent from this position and the drive wheels of the vehicle shift from the rotating state to the stopped state (hereinafter referred to as the half-clutch state position). (denoted as a point) is corrected depending on the wear condition of the facing of the friction clutch 31, the presence or absence of a loaded object, etc. In other words, from LE point to friction clutch 3
The stroke of the clutch plate 41 until the clutch plate 1 is completely engaged is always approximately constant, and the friction clutch 31 is smoothly engaged regardless of the state of the vehicle. When the LE point is corrected, it is determined whether the position of the change lever 54 and the gear position are the same, that is, the shift signal and the gear position signal are the same and the target gear (
D.E.

When the DP range is selected, it is determined whether or not the gear positions of the gear type transmission 32 are aligned (preset to 2nd speed, for example). 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 pressure has been reached, the tJ friction clutch 31 is is turned off, the air in the air tank 48 is used to operate an actuator (not shown), the gear position is automatically matched to the position of the change lever 54, the friction clutch 31 is connected, and the air tank 48 (main tank) and a sub tank (not shown) are connected. After turning off the switching solenoid valve, it is again determined whether 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 the air has reached the specified pressure, the switching solenoid valve is turned on. Then, the friction clutch 31 is disengaged, and the air in the sub-tank is used to operate the power cylinder to automatically select the gear position corresponding to the position of the change lever 54.

If 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 sub-tank is below the specified pressure. On the other hand, if the position of the change lever 54 and the gear position are the same, a relay for enabling starter is output. When the starter enable relay is output, the starter 63 can be started and the engine 30 can be started, so it is determined whether the engine 30 has started, and if the engine 30 has started, the starter enable relay is output. turn off,
If the engine 30 does not start, it is determined again whether the position of the change lever 54 and the gear position are the same. When the starter enable relay is turned OFF, it is checked whether the air in the air tank 48 and sub-tank has reached the specified pressure, and if the air has not reached the specified pressure, the air warning lamp 75 is turned on and the air is The judgment is repeated until the pressure reaches the specified pressure, and when the pressure reaches the specified pressure, the air warning lamp 75 is turned off and the starting process is completed.

After the start process is completed, the vehicle speed signal is read, and if it is below a specified value, the start process begins.

As shown in FIGS. 7(a) and (bl), 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. Next, the position of the change lever 54 and the gear position and determine whether they are the same or not.
If NO, adjust the gear position to the target gear position. When the position of the change lever 54 and the gear position become the same, it is determined again whether the vehicle speed is smaller than the specified value, and if the vehicle speed is higher than the specified value (No), the process proceeds to the step of detecting the accelerator load signal described later. move on. On the other hand, if this is not the case, it is read from the shift signal whether the next gear position that has reached the target gear position is neutral or not, and if YES, the LE point correction is performed again. If the gear position is other than neutral (NO), the friction clutch 31 is connected to the LE point. Next, it is determined whether the accelerator load signal value exceeds a specified value (voltage low enough to indicate the driver's intention to start), and if NO, which indicates that the driver has no intention to start, each of the steps described above is performed. Repeat. On the other hand, YE is judged to have the intention of starting.
In the case of S, the process proceeds to the next step, where the accelerator load signal value is detected, and the optimum duty rate a corresponding to this value is read from the map shown in FIG. Then, the pulse signal with the obtained optimum duty rate a is output to the solenoid valve 50, and et
a Clutch 31 is gradually connected. At this point, the CPU 66 outputs a selection signal to the input port 69 to continue inputting the signal of the engine speed N, and based on this engine speed NE(7) signal (the engine speed NE over time is stored in the memory). As shown in FIG. 9, which shows an example of changes in the engine rotation speed N, J and clutch rotation speed N.L, calculation processing is performed to obtain the peak point M. Until M is detected, go to NO and repeat from the accelerator load signal detection step.On the other hand, when the peak point M is detected, the solenoid valve 50
is held ON. Note that the peak point M occurs because the output shaft 30a of the engine 30 decreases as power begins to be transmitted to the driving wheels as rotation of the input shaft 44 of the gear type transmission 32 via the friction clutch 31. .

Next, the LEOFF routine is executed.

This LEOFF routine is used to deal with cases where the vehicle is slightly moved with the clutch in a partially engaged state rather than a normal start.In the LEOFF routine, it is first determined whether the vehicle speed is greater than a specified value; If YES, it is determined that it is a normal start, and the LEOFF routine ends and returns to the start flow. On the other hand, in the case of NO, it is next determined whether or not the accelerator pedal 37 is depressed, and in the case of YES, the LEOFF routine ends in the same way, and in the case of No, the LEOFF routine continues until the LE point is reached. The friction clutch 31 is disengaged. Meanwhile, 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 aforementioned accelerator load signal detection step. or,
After the friction clutch 31 has retreated to the LE point, the process returns to the step of determining the position of the change lever 54 and the gear position described above.

When the LEOFF routine is completed and it is determined that a normal start has occurred, the friction clutch 31 is connected from the half-clutch state at the LE point to clutch engagement, but at this time, the engine speed N after passing the peak point M is Clutch rotation speed N corresponding to the rotation of the input shaft 44 of the gear type transmission 8132. Considering that the engine speed gradually decreases as L increases, control is performed so that the rate of decrease in engine speed falls within a predetermined range and the shift shock becomes small. That is, first, it is determined whether or not the rate of decrease in engine speed Δm every predetermined period of time is less than or equal to the first set value 1x, 1 shown in FIG. If YES, after executing the above-mentioned LEOFF routine, the accelerator load signal is detected again and the optimum duty rate α corresponding to this value is determined, and the friction clutch 3 is
1 gradually. After this, the engine speed reduction rate ΔN
E is the second setting value lx, l (1x11 < 1x21
) or less, and if No, use the LEOF described above.
Return to before the F routine and check the engine speed reduction rate ΔNEG
Repeat the loop to keep it constant.

On the other hand, if the engine speed reduction rate ΔT is greater than lX11, it is determined whether the engine speed reduction rate ΔNE is greater than or equal to a third set value 1y21 (1x21 < 1y21). If YES here, after executing the LEOFF routine, the friction clutch 314 is
! Cut gradually. Thereafter, it is determined whether the engine speed reduction rate ΔN5 is equal to or less than the fourth set value 1y11 (lyj < 1y21), and if NO, the loop of disconnecting the friction clutch 31 is repeated. In the case of YES, or in the case of NO in the step of determining whether the engine speed decrease rate ΔN5 is 1y21 or less, the engine speed decrease rate ΔN,
If YES in the step of determining whether or not
It falls within the shaded area in the figure. Therefore, friction clutch 3
The air pressure of the friction clutch 31 is held at the current state because the conditions for switching to the connected state without excessively prolonging the shift time may be caused by a shift shock when the clutch 1 is in a half-clutch state. After this, CPU6
In step 6, it is determined whether the difference between engine speed NE and clutch speed NcL is less than a specified value (for example, IN, -NoJ = about 10 rpm), and if NO, the above-mentioned loop is repeated. After a predetermined time lag at T, the solenoid valve 50 is fully opened and clutch engagement is performed. Thereafter, after a predetermined time lag on the condition that the engine speed NE is equal to or higher than the idle speed, the CPU 66 determines the slip rate of the friction clutch 31 (the difference between the engine speed N, & the clutch speed N.L). /The engine speed N- is calculated and this value is compared with a specified value, and if it is below the specified value, the flow returns to the main flow.On the other hand, when the slip rate is greater than the specified value, the amount of wear on the friction clutch 31 is large. When it is determined that the clutch warning lamp 76 is present, an ON signal as a clutch wear signal is outputted to the clutch warning lamp 76 via the output boat 74 and a drive circuit (not shown), and the clutch warning lamp 76 is turned on.

After the starting process is completed, the CPU 66 reads the vehicle speed signal and, if the signal exceeds a specified value, starts the speed change process. Figure 8 (
al, (as shown in bl, first input boat 69
A selection signal is given to the brake to check whether the brake has failed or not. If the answer is YES, indicating that there is a brake failure, downshifting is performed one gear at a time to stop the vehicle as described later. on the other hand,
If the brake fail is NO, it is checked using an acceleration sensor, for example, whether or not sudden braking is being applied with deceleration exceeding a certain value. Since it will take a long time, return to the main flow and temporarily block the gear shifting operation. However, if the friction clutch 31 is disengaged even when the brake is applied suddenly, it will be determined that the gear shift is in progress, so the gear shift operation is completed and the friction clutch 31 is connected.

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 causes the specification of 1.2.3 other than DE. Gear stage division or Dp,
DI: Determine whether it is an automatic gear, an R gear, or an N gear.

1.2.3 In the case of the specified gear stage, the change lever 54
It is determined whether or not the position of and the gear position are the same, and if YES, return to the main flow, and if NO, proceed to the next step. In this step, the change lever 54 is positioned at one of the target gears 1, 2.3, and the current gear position before shifting is in the DP, D, range, which corresponds to a downshift from there. Decide whether or not to do so. If YES, it is determined whether the downshift can be performed without overrunning the rotation of the engine 30, and if NO, proceeding to the next step and warning the driver of the overrun with a reverse warning buzzer. Return to the main flow without changing gears.

If the determination as to whether or not there is an overrun is YES, a downshift operation is performed by one gear from the current gear position as follows. As shown in FIG. 11, which shows the operational concept of this downshift operation, the 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 is kept unchanged. Hold on. Then, the cut valve 49 is turned on for a predetermined period of time via the output port 74.
A signal is output to disengage the friction clutch 31, and a control signal is output to each electromagnetic valve 53 of the gear shift unit 51 to perform a downshift to a gear position one step lower than the gear position before shifting. Next, the clutch rotation speed N causes the electromagnetic actuator 38 to increase the engine rotation speed N via the output port 74 and the microcomputer 65. A voltage signal that causes the same rotation as L is output as an accelerator pseudo signal, and the clutch rotation speed NcL and engine rotation speed NE after shifting are output.
and then remove the air from the air cylinder 42.
The clutch 31 is moved to the LE point, a half-clutch state. Next, the IWA clutch 31 is connected at the optimum duty rate α corresponding to the accelerator load signal, and the difference between the engine rotation speed NE and the clutch rotation speed N is compared with a specified value preset for each gear, 1NE-NCL
The operation of connecting the friction clutch 31 at the duty rate α described above is repeated until ' becomes equal to or less than the specified value.

After 1NE-NCL' becomes below the specified value,
A clutch connection signal is output, the connection of the friction clutch 31 is completed after a predetermined time lag, the accelerator pseudo signal is released, and the process returns to the main flow. In addition, in the above operation, the clutch rotation speed N. If L exceeds the specified value, it is assumed that the friction clutch 31 is worn out, and the friction clutch 31 is not connected and the operation shown in FIG. 5 (al.
Proceed to the first connector in the middle and perform LE point correction.

On the other hand, if the result of the determination as to whether or not this corresponds to a downshift from the DE range is No, then a determination is made as to whether or not it is a shift up. If the answer is YES, a shift-up operation is performed as follows, and the process returns to the main flow. As shown in FIG. 12, which shows the operational concept of this shift-up operation, a control signal for the control rack 35 is outputted to the electromagnetic actuator 38 via the output port 74 and the microcomputer 65, and the engine rotational speed N is set to idle rotation. return. After disengaging the friction clutch 31, the gear position is outputted to each electromagnetic valve 53 via the output port 74 so as to match the target gear position, which is one of 1.2.3 as the designated gear position. do. Thereafter, the operation after outputting the accelerator pseudo signal of the downshift operation is performed to obtain the clutch rotation speed N after the gear shift. Match engine speed N and Q to L, 1ili! The connection of the friction clutch 31 is completed and the process returns to the main flow. If the result of the above judgment on whether or not to shift up is NO, it is judged whether or not the overrun is within the range, and when it is YES, the engine speed is held at the same state as N and Q, and the friction is reduced. The clutch 31 is disengaged, the gear position is adjusted to one of the designated gears 1 and 2.3, and the operations after outputting the accelerator pseudo signal of the downshift operation are performed, and the process returns to the main flow. Further, if the result of the determination as to whether or not the overrun is within the range is NO, a warning is issued by a warning buzzer.

The above operation is performed when the position of the change lever 54 is determined to be the specified gear 1, 2.3, and as a result of the determination of the position of the change lever 54, the forces DP and DE are If the vehicle is in the automatic gear position, the following operations are performed. That is, it is determined whether the vehicle speed is in the range or not, and the optimum gear position that is regarded as the target gear position in each range of DP or hemorrhoid is determined from a preset map as shown in FIG. Thereafter, it is determined whether the gear position matches the optimum gear position, and if YES, the process returns to the main flow. On the other hand, if NO, that is, if the gear position does not match the optimum gear position, it is then determined whether or not to shift up, and if not, perform the same operation as described above and return to the main flow. . On the other hand, in the case of upshifting, for example when the engine does not have much surplus horsepower, such as when the vehicle is on a hill, the vehicle speed will decrease even if the control rack 35 of the injection pump 34 of the fuel injection device is at full stroke. If this happens, you may not be able to maintain the vehicle speed before shifting. In that case, a wasteful operation of immediately downshifting and returning to the original gear position after the upshifting operation is performed. Therefore, in order to prevent this, when it is determined that the shift is up, the rack position sensor 7
7, the position of the control rack 35 of the injection pump 34 is detected to determine the current driving force, and the running resistance of the vehicle is determined from this driving force and acceleration force, and this running resistance is smaller than the effective driving force of the next stage. I only have it shift up occasionally. In other words, while Figure 13 shows the relationship between vehicle speed, running resistance, and driving force, the current driving force F at a certain gear (for example, n gear) is (current control rack position flS)/(rack full stroke s
), the driving force P in n stages, (Pl, = T, /
r0°P, (kg), T,: x engine torque,
It can be determined by multiplying ro: total gear ratio of n stages, Rt=tire radius). Furthermore, the acceleration force B can be determined for the first time. The running resistance A can be determined by subtracting the acceleration force B from the current driving force F. This running resistance A
When the driving force P x Q at the next stage (n+1) is ≧A, it is assumed that the vehicle has sufficient surplus horsepower. Therefore, in the case of upshifting, after reading the rack position, it is determined whether the running resistance is smaller than 7X (-driving force at the upper gear), and the gearshift operation is performed only if YES. If not, return to the main flow. Here, 7 is the efficiency of each gear stage, and the load weight (
It is determined from a preset map taking into consideration factors such as the vehicle's total weight, the slope of the slope, and the required acceleration after shifting. Furthermore, the 13th
For convenience of explanation, the figure shows current driving force F1 running resistance A @
The driving force P, , in the nth gear is shown at the same vehicle speed, but in reality, the vehicle speed decreases when shifting, so the current driving force F
The running resistance A is shown at the vehicle speed indicated by the two-dot chain line.

Further, if the result of the determination of the position of the change lever 54 is R gear, the CPU 66 determines whether or not the gear position matches R gear as the target gear, and selects YES if reverse operation is currently in progress. If so, return to the main flow, and if No, which is an erroneous operation, do the same as above and change the engine speed Nl.
:e Set to idle rotation and disengage w1 friction clutch 31. Then, in order to return the gear position to neutral, an output is sent to each electromagnetic valve 53 via the output port 74, and a reverse warning lamp that indicates a gear shift error is turned on.After this, the friction clutch 31 is connected to return to the main flow. return.

Furthermore, the result of determining the position of the change lever 54 is N.
In the case of gear shift, it is determined whether the change lever 54 has moved within a predetermined period of time, that is, whether the driver has merely passed through the N gear during the gear change operation. If the result of this judgment is YES during the gear shifting operation, the position of the change lever 54 and the gear position are judged as described above, and the process returns to the main flow or performs a shift up/down shift. An operation is performed to return to the main flow. However, in the case of No where the N stage is selected, the engine speed is lowered to NE8 idling speed, the friction clutch 31 is disengaged to set the gear position to neutral, and then the friction clutch 31 is connected again to return to the main flow.

In this embodiment, air pressure from an air tank 48 installed in the vehicle is used to drive the air cylinder 42 for operating the friction clutch 31, but it is of course possible to use hydraulic pressure as the control medium. However, in this case, a new hydraulic pressure generation source such as an oil pump must be added, which may increase costs.

Furthermore, it goes without saying that the speed change control procedure and shift change shown in this embodiment are possible, and the present invention can also be applied to a vehicle equipped with a gasoline engine. Furthermore, a dummy clutch pedal may be installed for a driver who is switching from a manual transmission, and in this case, the clutch pedal functions in priority over the air cylinder 42 in R gear and designated gears 1, 2, and 3. It is also possible to set it so that

<Effects of the Invention> According to the speed change control method for an automatic transmission of the present invention, a drive system such as a general friction clutch or gear type transmission is used as is, and air from an air tank installed in the vehicle is used as a control medium to control the friction clutch. Since the actuator and the power cylinder of the gear position switching means are operated to perform the gear shifting operation, it is possible to obtain a low-cost automatic transmission without significantly improving conventional vehicle production equipment. When upshifting in 1st gear operation, the stroke position of the control rack of the fuel injection system and the acceleration of the vehicle are detected, the current driving force and acceleration force are determined, and running resistance is determined. This running resistance is used as the effective drive for the next stage. Since the shift operation is not performed when the engine power is exceeded, there is an advantage that there is no need to perform unnecessary shift operations when the engine does not have much remaining horsepower.

[Brief explanation 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 its shift pattern, and Fig. 3 is an example of its shift characteristics between the Dp range and the To range. 4 is a graph representing an example of a map for determining the duty rate, and FIG. 5 is a graph representing an example of a map for determining the duty rate.
Figure 8(a). (bl, (cl) is a flowchart showing an example of the control program, FIG. 9 is a graph showing an example of changes over time in engine speed and clutch speed during gear shifting,
The figure is a graph showing the range of the rate of change in engine speed during gear shifting, and Figure 11 is a conceptual diagram of the operation during downshift operation.
FIG. 12 is a conceptual diagram of the operation during an upshift operation, and FIG. 13 is a graph showing the relationship between vehicle speed, running resistance, and driving force. 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, 42 is a An air 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, 65 is a micro combination μm, and 77 is a rack position sensor. be.

Claims (1)

[Claims] A friction clutch that connects to the output shaft of the engine, a clutch actuator that operates the friction clutch, a gear type transmission that connects the input shaft to the friction clutch, and a gear position switch that changes the gear position of the gear type transmission. and a control device for controlling the operation of the clutch actuator and the gear position switching means based on the driver's intention and the vehicle running conditions, in which the gear position is switched to a higher speed side. At this time, the stroke position of the control rack of the fuel injection device is detected, the current driving force is calculated based on the stroke position of the control rack, the current acceleration is detected, the acceleration force is calculated based on this acceleration, and the acceleration force is calculated. A speed change control method characterized in that a running resistance is determined from the current driving force and the current driving force, and if this running resistance exceeds the effective driving force of the next stage, no gear shifting operation is performed.