JPS63308258A - Control device for staged transmission for vehicle - Google Patents

Abstract

PURPOSE:To prevent the reduction in the engine brake action, when a downhill coasting condition of a vehicle is detected, by stopping the changeover of gear stage to a higher speed side to be carried out on the basis of a speed change diagram by a stopping means. CONSTITUTION:When a vehicle is in an accelerating or a steady running condition although the operating amount of an accelerator is zero, based on the signal from in accelerator nonoperation detecting switch 41 and the signal from an output shaft revolution sensor 52, the CPU 66 in a control unit 16 judges that the vehicle is in a downhill coasting running condition. In this downhill coasting running condition, although the vehicle speed increases to become in such a condition that a higher speed side gear stage than that at present is requested, the CPU 66, in this condition, fixes the target gear stage to the present gear stage, and prevents the changeover to a higher speed side gear stage. Thus, at the time of downhill coasting running, the reduction in the engine brake action attributable to the changeover to a higher speed side gear stage can be prevented.

Description

DETAILED DESCRIPTION OF THE INVENTION Technical Field The present invention relates to a control device for a stepped variable transmission for a vehicle.

Prior Art A type of geared transmission that includes a shift control means that operates a shift actuator of a stepped transmission having a plurality of types of forward gears according to a previously stored shift diagram, and automatically shifts the stepped transmission by the shift actuator. A stepped transmission for a vehicle is known. For example, in a fully automatic manual transmission, the shift fork of a synchronized mesh transmission, which was conventionally operated manually, is now operated by a hydraulic cylinder.1. That's John. In such stepped transmissions, as described in Japanese Patent Application Laid-open No. 59-81230, etc., the timing of changing gears is determined based on the actual accelerator operation amount and vehicle speed from a pre-stored shift diagram. A control device is provided for automatically switching gears of the stepped transmission.

Problems to be Solved by the Invention However, in the conventional stepped transmission control device,
Regardless of the driving condition of the vehicle, the gears are switched according to the transmission diagram, so when the vehicle is coasting downhill, the gears may not be on the high-speed side even though engine braking is expected. In some cases, the engine brake was switched to , and sufficient engine braking action could not be obtained.

Means for Solving the Problems The present invention has been made against the background of the above circumstances.
The object is to provide a control device for a stepped transmission that can generate sufficient engine braking action even when traveling downhill.

In order to achieve such an object, the gist of the present invention is to change the shift actuator of a stepped transmission having a plurality of types of forward gears to a pre-stored speed change, as shown in the claim correspondence diagram of FIG. A control device for a stepped transmission for a vehicle, comprising a shift control means operated according to a diagram, and for automatically shifting the stepped transmission by the shift actuator, (b) when the vehicle is in a downhill running state, a gear shift that prevents a shift to a high speed gear based on the shift diagram; and prevention means.

Operation and Effect of the Invention With this arrangement, when the downhill coasting state of the vehicle is detected by the downhill coasting detecting means, the gear shift to the high speed side based on the shift diagram can be performed. This is prevented by the gear stage switching blocking means. Therefore, during downhill coasting, the decrease in engine braking effect caused by switching to a high speed gear is completely eliminated.

EXAMPLE Hereinafter, an example of the present invention will be described in detail based on the drawings.

In FIG. 2, power from a vehicle engine 10 is transmitted to drive wheels via a magnetic particle electromagnetic clutch 12, a stepped transmission 14, and a differential gear (not shown).

The magnetic particle electromagnetic clutch 12 functions as an automatic clutch in this embodiment, and is inserted between the crankshaft 15 and the input shaft 46 of the stepped transmission 14, as shown in FIG. Then, the torque is controlled by the excitation current supplied from the control device 16, and a torque corresponding to the excitation current is transmitted.

The crankshaft 15 and the input shaft 46 of the stepped transmission 14
correspond to the input shaft and output shaft of the magnetic particle type electromagnetic clutch 12. The stepped transmission 14 is a synchronized mesh transmission with five forward speeds and one reverse speed, which is well known as a manual transmission. and a shift rod 18 to which a shift fork (not shown) is attached for shifting to the second gear.
, a shift rod 20 to which a shift fork 19 for shifting to the third and fourth gears is attached, and a shift fork (not shown) for shifting to the fifth and reverse gears is attached. Shift rods 22 and those shift rods 18.20.22
A shift device is provided for selectively driving the shift position from the neutral position to the shift position. The shift device includes a 3-position hydraulic cylinder 26 for shifting that drives the shift select lever 24 in the rotational direction to drive either of the shift rods 18, 20. and a three-position switching hydraulic cylinder 28 that engages the lower end of the shift select lever 24 with either of the shift rods 18, 20, 22 by positioning at three positions in the direction of the rotation axis. We are prepared. The 3-position hydraulic cylinder 26 for shifting is controlled to 3 positions by a combination of the operation of a pair of solenoid valves 30 and 32, and the 3-position hydraulic cylinder 28 for switching is also controlled by a combination of the operation of a pair of solenoid valves 34 and 36. It is designed to be controlled in three positions by a combination of. That is, due to the combination of the operations of the electromagnetic valves 30, 32, 34 and 36, the hydraulic pressure supplied from the hydraulic pump 37 to the hydraulic circuit 38 is transferred to the 3-position hydraulic cylinder 26 for shifting and the 3-position hydraulic cylinder 28 for switching. For example, when the electromagnetic valves 34 and 36 are both on, the three-position switching hydraulic cylinder 28 moves the shift select lever 24 to the shift rod for switching between the third gear and the fourth gear. 20, but the solenoid valve 34
is on and the solenoid valve 36 is off, the three-position switching hydraulic cylinder 28 moves the shift select lever 24 to the first position.
When engaged with the shift rod 18 for switching between the first gear and the second gear, on the other hand, when the solenoid valve 34 is off and the solenoid valve 36 is on, the 3-position switching hydraulic cylinder 28 operates as a shift select lever. 24 is engaged with the shift rod 22 for switching between the fifth gear and the reverse gear. Further, when both the solenoid valves 30 and 32 are on, the 3-position hydraulic cylinder 26 for shifting is positioned in the neutral state, but when the solenoid valve 30 is on and the solenoid valve 3
2 is off, the 3-position hydraulic cylinder 26 for shifting moves one of the shift rods to the 1st, 3rd, and 5th speeds, and on the other hand, the solenoid valve 30 is off and the solenoid valve 32 is When it is on, the three-position hydraulic cylinder 26 for shifting moves any one of the shift rods to the second speed, fourth speed, or reverse side. FIG. 6 shows the relationship between the movement locus of the upper end of the shift select lever 24 and the gear stage established thereby.

The vehicle is equipped with various sensors for detecting driving conditions, and signals from these sensors are sent to the control device 16.
is being supplied to.

That is, the accelerator sensor 42 provided on the accelerator pedal 40 outputs a voltage signal ac representing the amount of accelerator operation.
c is output to the control device 16. An accelerator non-operation detection sensor 41 for detecting that the accelerator pedal 40 is in the non-operated position is also provided, and from there, an accelerator non-operation signal A no is output to the control device 16 . Further, the shift down push button switch 43 is connected to a shift lever (not shown).
Or it is installed on the instrument panel, etc.
The shift down designation signal ssh is output to the control device 16. An engine rotation speed sensor 44 provided in the engine 10 outputs a signal t9 synchronized with engine rotation to the control device 16. Input shaft rotation sensor 5 provided near input shaft 46 and output shaft 48 of stepped transmission 14
0, and a signal j in synchronized with the rotation of the input shaft 46 and a signal t synchronized with the rotation of the output shaft 48 from the output shaft rotation sensor 52. , is output to the control device 16. Additionally, a shift position detection switch 54 provided in the stepped transmission 14
．． From 56.58.60, the signal Ns,,1 to N $W
4 is output to the control device 16. The operating position of the 3-position hydraulic cylinder 26 for shifting is detected by a combination of signals from a pair of shift position detection switches 54 and 56, and the operating position of the 3-position hydraulic cylinder 26 for switching is detected by a combination of signals from a pair of shift position detection switches 58 and 60. 28 operating positions are detected. These shift position detection switches 54, 56, 58, and 60 are similar to those described in Utility Model Application No. 1983-41977, which was previously filed by the present applicant. Furthermore, a throttle sensor 84 for detecting the opening degree of the throttle valve 80 is provided, and an output signal from the throttle sensor 84 is manually input to the control device 16.

The control device 16 includes a CPU 66, a ROM 68, and a RAM 70.
, a human power interface 72, a clutch drive circuit 74, a throttle drive circuit 76, a solenoid valve drive circuit 78, an LED drive circuit 86, and the like. The input signal is processed according to the programmed program, and a drive signal for driving the solenoid valves 30, 32, 34, 36 is outputted from the solenoid valve drive circuit 78, and an excitation current for controlling the electromagnetic clutch 12 is sent to the clutch drive circuit. Output from 74. Additionally, the throttle drive circuit 76
From there, a drive signal is output to a throttle actuator 82 that drives a throttle valve 80 provided in the intake pipe of the engine 10.

Further, the LED drive circuit 86 outputs a drive signal to an LED display 88 that indicates that the engine brake shift control is being performed.

FIG. 7 shows an example of the output terminal configuration of a solenoid valve drive circuit 78 consisting of 4 bits and 7 bits from bit 0 to bit 3. Bit 0, bit 1, bit 2, and bit 3 correspond to solenoid valves 30, 32, and 34, 36, respectively. Similarly, FIG. 8 shows an example of a partial configuration of the input terminal of the input interface 72, which consists of four bits from bit 0 to bit 3. The 0th bit, 1st bit, 2nd bit, and 3rd bit correspond to shift position detection switches 54, 56, 58, and 60, respectively.

Next, the operation of the shift control device for an automatic transmission constructed as described above will be explained according to the flowcharts shown in FIGS. 1(a) and 1(bl).

First, in step S1, the input signal t from each sensor is
o,”=nz Lout, Vscc % V, N
swl~N,,4,A,,. , S sh is RAM7
It is read into a predetermined area within 0. Then, step S
2, from the above signal the following equations (1), (2), +3
1. (41,+5+, (6).

According to (7), the actual engine rotation speed N, input shaft rotation speed N in, output shaft rotation speed N0゜2, vehicle speed SPD, vehicle acceleration dSPD, accelerator operation amount A
(C% throttle valve opening θ is calculated.

Na (rpm) - (1/to) x50se
c...(llN, 7 = (1/l,,,)×6
03eC...(2) Nout -(1/tout
)X 60sec ・ ・ 13) SPD (
km/h) =Nout・γdif '2π
r, 60 □0. ．．・1/1000 ・ ・ ・(4
) However, r is the radius of the wheel, γ68. This is the gear ratio of the differential gear.

dSPD (m/s”) = (SPDtn+ 5P
Dt++-ti+) / ji... This is the previous value.

A cc = (VIICCVetosa)/(V+
++ax Vctose)・100...(6) However, vchos. and V□, is the accelerator pedal 40
This is an output signal from the accelerator sensor 42 when the accelerator is not operated and when the accelerator is fully operated.

θ (%) = (y,, ,c+os″)/
(vIIIX-vc(os・), 100・・・・(7
) However, 1. ctoso and v m ''X are output signals from the throttle sensor 84 when the throttle valve 80 is fully closed and fully open.

In the subsequent step S3, the current gear position calculation routine shown in FIG.
4 to N51, the current gear stage is detected. Since the signals N, . That is, when none of the signals N5U4 to N581 are supplied, the binary number γ5w becomes "0", so the stepped transmission 14 is determined to be in the neutral state, and the signals N,
, 2 and N, , , 4 are supplied, then the binary number γS
Since w is "5", it is determined to be the first gear, and the signal N
, , 2 and N 3 are supplied, the binary number B becomes ``
6", it is determined to be the 2nd gear, and the signal N3□4
If only the binary number γ8. , is "1", so it is determined that it is the third gear, and if only the signals N and 3 are supplied, the binary number γS.

is "2", so it is determined that it is the 4th gear, and the signal N5 is activated.
．． 1 and N□4 are supplied, the binary number γs,,
is "9", so it is determined that it is the 5th gear, and the signal N5
When w1 and N13 are supplied, the binary number γSw becomes "10", so it is determined that the gear is in reverse gear, and
Neutral to the value “0” indicating the current gear position),
rlJ (first gear), r2J (second gear), r3J (third gear), r4J (fourth gear)
5th gear), "5" (5th gear), r6J (
I-adary gear stage) is stored in register γ.

In the subsequent step S4, it is determined whether or not the content of the shift sequence flag FCh9 indicating the content of the shift operation is "0". If it is not "0", the step described below is used to preferentially continue the shift control.

Step S18 and subsequent steps are executed, but if it is "0", it means that the shift operation has been completed, so the first step is executed in step S5.
The target gear position is determined by executing the target gear position determination routine shown in FIG.

That is, in steps SMI to 5M12, a shift diagram corresponding to the actual gear stage is selected from a plurality of types of shift diagrams stored in advance in the ROM 68 based on the numerical value in the register T indicating the actual gear stage. In step 5M13, the upshift shift point vehicle speed SPD, p and the downshift shift point vehicle speed SPD, are calculated by interpolation based on the actual throttle valve opening from the shift diagram. 7. , is calculated. Then, in step 5M14, when the actual vehicle speed SPD becomes equal to or higher than the upshift shift point vehicle speed 5PDup, in step 5M15, the contents of the register γ1 that stores a numerical value indicating the target gear stage are set to γ+1, but in step 5M16, the actual vehicle speed is set to γ+1. Shift point vehicle speed SPD when vehicle speed SPD downshifts,
. 8 and below, the contents of register γ1 are set to r-1 in step 5M17. That is, register γ9
The content of the gear is set to be one gear higher than the current gear or one gear lower than the current gear. 1st
Figure 2 (al, (bl, (C) is the step SM2.3 above)
Examples of shift diagrams selected in M4.5M10 are shown, with the solid line being an upshift diagram and the broken line being a downshift diagram. Also, step 5M above
13, for example, if the shift diagram is as shown in FIG. 13, the calculation of the shift point vehicle speed from the data map that constitutes the diagram is based on the actual accelerator operation iA. 0 and the X-axis data on the map, and when Ace<X-axis data is set as X2, and the previous X-axis data where Ace<X-axis data is set as X+, the following formula (8) is obtained.
It is carried out according to the following.

FIG. 1 (Returning to al., the target gear stage γ is set as described above.
1 is determined, in step S6, in order to confirm whether the current driving state is a coasting driving state, the accelerator operation amount ACC is set close to the value at idle, that is, the fully closed operation amount A, It is determined whether or not it is greater than cidL (#0). If the value is larger than that, it can be determined that the vehicle is accelerating, so step S9 is executed and the contents of the engine brake control flag FEGB are reset (initialized) to "0" to indicate cancellation of engine brake control. . However, the accelerator operation ffi A c c is the fully closed operation amount A6. If it is smaller than "dl, it can be determined that the vehicle is coasting or decelerating without stopping, so step S7 is executed to determine whether or not engine braking is necessary. In other words, step S7 is executed. 7 is used to check the previous control state in order to prevent the release of the engine brake due to variations in vehicle acceleration dSPD or changes during gear shifting, and is an engine brake control flag F. If the content of G8 is "0" It is determined whether or not there is. When the content of the engine brake control flag F Ecs is "0", the previous state was not engine brake control, so step S8 is executed to determine whether engine brake control is necessary. When it is determined that the content of the brake control flag FEG11 is not "0" (it is 1), the previous state is the engine brake control state, so the engine brake control is maintained in step SIO, and the current state is The engine brake control flag F is used to remember that the speed change control is engine brake control.

The contents of is set to 1.

In step S8, it is determined whether the vehicle acceleration dSPD is greater than a predetermined constant value α. This constant value α is, for example, the acceleration (negative value) when the vehicle coasts and decelerates on a flat road in neutral.

If it is determined that the vehicle acceleration dSPD is not greater than the constant value α, the engine brake control flag F is set in step S9, since the vehicle is decelerating and does not require engine brake action. The content of is set to "0".

However, if it is determined that the vehicle acceleration d5PI) is larger than the constant value α, the engine is in a coasting state where the vehicle is accelerating or traveling at a constant speed even though the accelerator operation amount is zero. Since a brake is required, the engine brake control flag F is set in step S10.

The content of is set to "1". As described above, in steps S6 and S8, it is determined whether the accelerator is running at an accelerating speed or steady running even though the accelerator operation amount is zero, so steps S6 and S8 are used for downhill coasting in this embodiment. Corresponds to the detection means.

In the following step Sll, it is determined whether or not the target gear T<b>2 determined in step S<b>5 indicates a gear higher than the actual gear γ in the state of engine brake control.

If the target gear T8 does not indicate a gear higher than the actual gear γ, step S13 is executed.

However, if the target gear T1 indicates a gear higher than the actual gear γ, the vehicle speed increases due to downhill coasting and a gear higher than the current gear T is requested. However, if this requirement is satisfied, sufficient engine braking action cannot be obtained, so step S1
3, in step S12, the target gear γ1 is fixed to the current gear T in order to prevent switching to a high speed gear during downhill coasting. In this embodiment, the above step S12 corresponds to gear stage change prevention means.

In step 313, it is determined based on the signal 5ash whether the downshift push button switch 43 has been operated. If it is determined that the downshift switch is not being operated, it means that there is no downshift request from the driver, so the contents of the downshift switch flags F4 and Isw are reset to zero in step S14. - However, if it is determined that the shift down push button switch 43 has been operated, it means that there has been a request from the driver, so in order to prevent continuous downshifts, the shift down push button switch 43 in the previous control cycle should be pressed. 43 is not operated, in other words, the shift down switch flag Fa,,ns
It is determined in step S15 whether the content of y is "0". Shift down switch flag Fawns
If the content of w is "0", the shift down pushbutton switch 43 was not operated in the previous control cycle and this is the first operation determination, so the content of the target gear stage γ8 is changed to the current value in step S16. The gear position is updated to a lower speed side than the gear position γ, and step 317 is executed to set the content of the downshift switch flag Fdwn*w to "1". However, if it is determined that the content of the shift down switch flag F dWlI SW is already rlJ, steps S16 to S317 are not executed in order to prevent a subsequent downshift, and the gear shift is performed based on the target gear stage γ8. Steps 318 and subsequent steps are performed to shift gears or perform half-clutch control for starting.

In step 318, whether or not the gear is being shifted is determined based on the content of the gear shift sequence flag Feh9, and if the content of the gear shift sequence flag F,69 is rOJ, the clutch control is executed as the vehicle starts and stops. Step 319 and subsequent steps are executed, but the shift sequence flag F
If the content of ch* is "4", it is assumed that only the gear stage is being changed and steps 326 onwards are executed, and the content of shift sequence flag F ch9 is not "0" but "4".
”, it is determined that the shift is being performed while driving and requires throttle operation and clutch operation, and the process proceeds to step 822.
The following will be executed:

In step S19, the rotational speed N of the human power shaft 46 is determined in order to determine whether the vehicle is starting with the clutch disengaged or semi-engaged or traveling with the clutch engaged.
Absolute value IN of the difference between i h and engine rotational speed N8, -
It is determined whether Ni,l is larger than a predetermined criterion value ΔN.

If it is large, there is a slip and the clutch 12 is not yet fully engaged, so it is assumed that the vehicle is starting or stopping, and step S25 is actually executed. However, if it is determined that IN, -Ni, 1 is less than or equal to ΔN, then the electromagnetic clutch 12 is fully engaged and the vehicle is running coupled, so steps 320 and subsequent steps are not executed. Ru. In this step S20, it is determined whether or not the current gear position γ and the target gear position T8 match each other. If they do not match, the process proceeds to step S21 in order to shift the gear position of the stepped transmission 14. After the contents of the shift sequence flag Fchq are set to rlJ, the shift operation routine of step S22 is executed.

The content of the shift sequence flag Fch9 is “
When it is "0", the shift operation is completed, that is, the control for starting and stopping the vehicle is performed, when it is "1", the power cutoff step of the shift operation is performed, and when it is "2", it is the control for starting and stopping the vehicle. When it is "3", it represents the power cutoff step of the speed change operation, and when it is "4", it represents the gear change step of the speed change operation, and when it is "4", it represents the gear change operation that does not involve throttle operation or clutch operation. It is. Above step S2
1, the content is set to "1" in order to execute the power cutoff process.

FIG. 14 shows a speed change operation routine in step S22 for switching the gear position of the stepped transmission 14 to the target gear position indicated by the contents of the register T1, in which a predetermined speed change operation is performed.

First, in step SHI, the shift sequence flag F
The contents of Ch9 are determined. Shift sequence flag F
If the content of chq is "1", a series of steps SH2 to SH5 are executed to start the power cutoff process. In step SH2, the actual throttle valve opening θ is determined to be the minimum opening θ6. . It is determined whether or not it is greater than 38. If not, steps SH6 and subsequent steps to be described later are executed to switch the meshing of the gear stages, but if it is, in step SH3, the control value for the throttle actuator 82 is decreased by a constant value ΔV.

In the subsequent step SH4, the control value Vc (for the electromagnetic clutch 12) is maintained at the previous control value VCLffi-11, and each electromagnetic valve 30, 32, 34 for shifting is maintained at the previous control value VCLffi-11.
．． The content of the control value VShift for 36 is zero, that is, a state in which no drive signal is output to any solenoid valve. Then, in step SH5, the contents of the shift sequence flag Feh* are set to rlJ. While the above series of steps are repeated, the throttle actuator 8
When the control value V2 for V2 is decreased, the throttle valve opening θ is determined to be the minimum opening in step SH2, and thereafter steps SH6 and subsequent steps are executed.

In step SH6, it is determined whether the actual gear stage stored in the register γ and the target gear stage stored in the register γ1 match, and if they match, the gear stage switching operation is completed. Therefore, steps from step 5 HIO to be described later are executed, but - if there is no defeat, step SH
In order to release the electromagnetic clutch 12 at step 7 and avoid gear shift failure due to engine inertia, etc., the control value ■
6 is set to zero, and the control value Vth, which has already been set to zero, is maintained at that value in order to fully open the throttle valve opening θ and prevent the engine 10 from revving up.

After the gear change routine of step SH8 is executed, the shift sequence flag F is set in step SH9.
The content of eh9 is set to "2".

The gear stage switching routine of step SH8 is executed, for example, as shown in FIG. 15. First step SGI
By processing the data indicating the target gear stage stored in the register T1 using the signal processing routine shown in FIG. Convert to a number that can be output as a bit array. That is, in order to convert the data indicating the target gear stage into data having the same arrangement as the input terminals of the input interface 72 shown in FIG. shift side data 7'sh and select side data T88. for operating the switching hydraulic cylinder 28. is converted into For example, if the target gear is the 1st gear, the shift side data 7'ih is "1".
If the select side data r'sL is r4J and the target gear is the second gear, the shift side data r'sh is "2" and the select side data T05. is set as "4",
If the target gear stage is the third gear stage, shift side data γ
sh is "1" and the select side data r"st is "0", and if the target gear stage is the 4th gear stage, the shift side data 11'□ is "2" and the select side data T11SL is "0". If the target gear is the fifth gear, the shift side data γ''' is rlJ and the select side data γ1.
8. is set to "8", and if the target gear stage is the 6th speed (reverse) gear stage, the shift side data r'sh is set to "2" and the select side data T8I is set to "8".

Returning to FIG. 15, in the following step SC, 2, the contents of the register T are converted into shift-side data T□ and select-side data TIL by a processing routine not shown, just as described above. These shift side data T. and select side data γ3L are the shift position detection switches 54 and 56.
．． The signal N,..., 4 to N, 81 supplied from 58 and 60 to the input interface 72 is composed of the lower 2 bits and the upper 2 bits (numerically including the lower 2 bits of rOJ). You can also do this.

In step SG3, select side data T8. based on the target gear stage. ．． and select side data 7 based on the actual gear stage.
At step SG4, shift side data γゝ5 based on the target gear stage is determined.
．． It is determined whether or not the shift side data γ5h based on the actual gear position match. Steps SG3 and SG
If both of the determinations in step 4 are affirmative, there is no need to change gears, so step SG5 is executed and the content of control value VShifL is set to zero. However, if the determination in step SG3 is affirmative but the determination in step SG4 is negative, step SG6 is executed and the contents of the control value 5hift are set as shift-side data γ lk based on the target gear position.

As a result, the three-position hydraulic cylinder 26 for shifting is driven in step S33, which will be described later, and the target gear stage is established. Further, if the determination in step SG3 is negative, it is necessary to use a shift rond different from that currently engaged by the shift select lever 24, so in step S07 the shift side data T based on the actual gear position is . is zero, that is, 3 for shift
It is determined whether the position hydraulic cylinder 26 is in the neutral position. If the judgment in step SG7 is affirmative, the control value V I h i is set in step SG8 in order to operate the 3-position switching hydraulic cylinder 28 to the position for selecting the shift rond for operating the target gear.
The contents of fL are select side data γ based on the target gear stage.
1 ISl. However, if the determination in step SG7 is negative, the content of the control value V□ift is set to "3" in step SG9 in order to operate the three-position shift hydraulic cylinder 26 to the neutral position. Since the content "3" of this control value vshirt is "11" in binary, in step S33, the solenoid valves 30 and 30 are
A drive signal is output to each. When the three-position hydraulic cylinder 26 for shifting is operated to the neutral position in this way, the next cycle's step SG8 and step 3 are
Shift Rondo is selected in step 33, and the target gear stage is established in step SG6 and step S33 in the next cycle.

When the execution of the gear changeover routine in step SH8 is completed in this manner, the register γ1 in which the numerical value indicating the target gear is stored matches the register T in which the numerical value indicating the actual gear is stored. So the 14th
The determination at step SH6 in the figure is affirmative, and a series of steps 5HIQ to 5H14 for power retransmission is executed. That is, in step 5HIO, it is determined whether the actual throttle valve opening θ is smaller than the accelerator operation 'FJ Acc. Since it is initially small, the control value Vc for the electromagnetic clutch 12 is set in step 5HII.
L is increased by a predetermined constant increase value ΔVCL. In the following step S H12, the above control value ■. It is determined whether or not the transmission torque value T (11) of the electromagnetic clutch 12 is determined in advance. This is predetermined for opening, and corresponds to a relatively small transmission torque after the electromagnetic clutch 12 starts engaging.If the judgment in step 5H12 is negative, the electromagnetic clutch 12 is not sufficiently engaged. If the throttle valve is opened without opening the throttle valve, the engine 10 may idle, so step 5H13 is skipped, and the content of the shift sequence flag Fch9 is set to "3" in step 5H14.The above steps are repeated and executed. Step 5H
When the control value ■e1 for the electromagnetic clutch 12 is increased by II, the judgment in step 5H12 is affirmed, so step SH13 is executed and the control value ■e1 for the throttle actuator 82 is increased by a predetermined constant value ΔV. The content of the shift sequence flag Fch* is set to "3" in step 5H14. Then, in the process of repeatedly executing steps 5HIO to 5H14, the control value I is sequentially increased so that the throttle valve opening θ becomes the target throttle valve opening θ each time. 2 will be followed. As a result, the judgment in step 5HIO is affirmed, so step 5
HI5 is executed and the contents of the shift sequence flag Fchg are set to "0". As mentioned above, the shift operation routine in step 322 of FIG. 1(b) automatically executes the shift operation in a predetermined order in order to establish the target gear T vehicle determined in step S5. The above steps s5 and S22 correspond to the shift control means of this embodiment.

When the speed change operation routine of step S22 in FIG. 1(b) is completed as described above, in step S33
. Control values such as I, ■, and Vshi□ are output to drive the electromagnetic clutch 12, throttle actuator 82, electromagnetic valves 30, 32, 34, 36, and the like. As a result, the gear position of the stepped transmission 14 is switched to the target gear position. Further, in this step S33, when the content of the flag FEC11 is "1", the LED indicator 88 indicating downhill coasting is turned on.
A drive current is output from the drive circuit 86.

In step S20, if it is determined that the current gear position γ and the target gear position T1 match, it means that the gear shift operation has been completed, so input is required for clutch control when the vehicle is stopped. Shaft rotation speed N0. , is the clutch release reference rotation speed N07. It is determined in step S23 whether or not the value is larger than . A value slightly larger than the idle rotation speed of the engine 10 is adopted as this clutch release reference rotation speed N of f . Above step S2
If it is determined in step S3 that Nln>Note, there is no risk that the rotation of the engine 10 will stop or become unstable, so step S24 is executed and the electromagnetic clutch 12 is operated 1v. is set to the maximum value y, max, and the electromagnetic clutch 12 is brought into a fully engaged state. However, contrary to the above, in step S23, N,...≦N0
1. If it is determined that the engine 10 stops rotating or becomes unstable, step S is performed.
30 is executed and the operation on the electromagnetic clutch 12-35
1v. , is set to the minimum value "0", and the electromagnetic clutch 12 is released.

Further, if it is determined in step S19 that the engagement of the electromagnetic clutch 12 is not completed, in step S25, similarly to step S20, the target gear stage Tm indicated by the contents of the register T1 and the register T It is determined whether or not the actual gear stage T indicated by the content of is lost. If the target gear T1 and the actual gear match, the gear shift operation has been completed but the engagement of the electromagnetic clutch 12 has not been completed, so whether the vehicle starts or stops depends on the accelerator in step S29. It is determined based on the operation "It A c c. That is, the accelerator operation amount A (
It is determined whether or not (is larger than the minimum value A Cci d (). If the determination in step S29 is negative, it is not a start, so the control value VCL for the electromagnetic clutch 12 is set to "0" in step S30. However, if the determination in step S29 is affirmative, the vehicle is in the starting state, so step S31 is carried out and the control value VCL is determined according to the control equation for starting the vehicle shown in the following equation (9). be done.

In control formula (9), the engagement torque is increased as the difference between the engine rotational speed N and the idle rotational speed N8□ increases, so that a transmission characteristic similar to that of a so-called centrifugal clutch is obtained.

■,, = (N, -Ni□)XK (9) However, K is a control constant.

Then, as described above, steps S24, S30, S31
Control values during normal driving, stopping, and starting of the vehicle. When is determined, in step S32, the control value vth for the throttle actuator 82 is set to the actual accelerator operation amount Acc, so that the throttle valve opening θ is set to the opening corresponding to the accelerator operation IAcc.

In step 318, the shift sequence flag Fc
If it is determined that the content of hs is "4", or if the determination in step 325 is negative, step 326 is executed, so that the content of the shift sequence flag Fch* becomes "4". After being done,
In step S27, the control value ■ for the electromagnetic clutch 12 is set so that the electromagnetic clutch 12 is maintained in the released state and the throttle valve 80 is maintained in the fully closed state to facilitate the establishment of a gear stage.
d and the contents of the control value □ for the throttle actuator 82 are set to zero, and in step 328, a control value V□ift for switching gears is determined according to the routines shown in FIGS. 15 and 16.

Steps 826 to 328 as described above are executed when the target gear stage γ1 is updated to "1" or the like while the electromagnetic clutch 12 is released when the vehicle is started.

As described above, according to the present embodiment, it is determined in step S6 that the vehicle is in the coasting state, and it is determined that the acceleration dSPD of the vehicle is larger than the predetermined value α in step S8. , the necessity of engine braking of the vehicle (ls hill coasting state) is determined, and even if the target gear stage γ8 is updated by a shift request when engine braking is thus necessary, step 512 Target gear stage γ1
By causing the actual gear T to be defeated, the gear change is prevented. Therefore, when the vehicle is coasting downhill, an upshift is prevented, so that the reduction in engine braking effect caused by upshifting can be eliminated, and the engine braking effect can be effectively maintained.

Furthermore, when the necessity of engine braking is determined as described above, the LED display 88 is lit based on the content "1" of the flag F EGII, so the driver can easily determine the necessity of engine braking. It is possible to grasp the state in which something is. Furthermore, if the engine braking effect is not sufficient when the LED display 88 is lit, operating the downshift push button switch 43 will cause the downshift operation to be one gear lower than before. Therefore, the desired engine braking effect can be further obtained.

Although the embodiment of the present invention has been described above based on the drawings, the present invention can also be applied to other aspects.

For example, in the above embodiment, when the target gear 11' is determined to be higher than the current gear γ in step 312, the target gear T8 is updated to the current gear T. Although upshifting during downhill coasting is prevented, the 3-position hydraulic cylinder 2 for shifting
6 and the 3-position switching hydraulic cylinder 28 are maintained in the operating state during downhill coasting.
Mechanical or electrical means may be provided which are activated in the second execution condition.

Further, in the above embodiment, the vehicle acceleration d SPD was calculated in step S2, but the actual vehicle acceleration may be detected using an accelerometer.

In addition, in steps S6 and S8, downhill coasting was detected based on the accelerator operation amount and vehicle acceleration, but instead of using an accelerometer that detects vehicle acceleration and an inclinometer that detects vehicle inclination angle. Downhill coasting of the vehicle may also be detected.

Furthermore, although the aforementioned stepped transmission 14 was a synchronous mesh type transmission, it is a planetary gear type stepped transmission in which gears are switched by selectively operating a plurality of frictional engagement devices. There is no problem even if there is.

It should be noted that the above description is merely an example of application of the present invention, and various modifications may be made to the present invention without departing from the spirit thereof.

[Brief explanation of the drawing]

1(al) and (b) are flowcharts illustrating the operation of the control device shown in FIG. 2. FIG. 2 is a block diagram showing a control device for a stepped transmission which is an embodiment of the present invention. Fig. 3 is a diagram showing the characteristics of the electromagnetic clutch shown in Fig. 2. Figs. 4 and 5 are diagrams showing a hydraulic drive device for switching gear stages of the stepped transmission shown in Fig. 2. FIG. 6 is a cross-sectional view of essential parts seen from mutually perpendicular cross sections.
The figure shows the relationship between the locus of the end of the shift select lever in FIGS. 4 and 5 and the shift position. 7 and 8 are diagrams for explaining the terminal configuration of the electromagnetic valve drive circuit shown in FIG. 2 and the terminal configuration of a part of the input interface, respectively. Figure 9, Figure 10, Figure 11, Figure 14,
FIGS. 15 and 16 are similar to FIGS. 1(a) and (b).
1 is a diagram showing each routine executed in the flowchart of FIG. FIGS. 12(a), (bl, and C) are diagrams respectively showing shift diagrams stored in advance in the ROM of FIG. 2, and (a) is a diagram selected at the first gear stage. , (b) is a diagram selected in the second gear stage, and (C) is a diagram selected in the fifth gear stage. FIG. 13 is a diagram for determining the shift point vehicle speed in the flowchart of FIG. 11. Fig. 17 is a diagram illustrating the claims of the present invention. 10: Engine 14: Stepped transmission 26: 3-position hydraulic cylinder for shift (shift actuator) 28: 3-position for switching Hydraulic cylinder (shift actuator) Fig. 1 (a) Fig. 3 Fig. 6 Fig. 7 Fig. 8!! 3 Fig. 5 Fig. 12 Fig. 13 km/h 7 rtle 1 Tosakut Acc

Claims (1)

[Scope of Claims] A shift control means for operating a shift actuator of a stepped transmission having a plurality of types of forward gears according to a shift diagram stored in advance, the shift actuator automatically controlling the stepped transmission. A control device for a stepped variable transmission for a vehicle, which is configured to shift the transmission to a downhill coasting state, comprising: downhill coasting detecting means for detecting a downhill coasting state of the vehicle; when the vehicle is in a downhill coasting state, A control device for a stepped transmission for a vehicle, comprising: gear change prevention means for preventing gear change to a higher speed side performed based on the shift diagram.