JP2885000B2 - Transmission control device for automatic transmission - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a shift control device for an automatic transmission, and more particularly to a transition control for returning from an automatic engine brake control to a normal shift control.

[0002]

2. Description of the Related Art An automatic transmission having a plurality of shift speeds, and a shift control means for changing a shift speed of the automatic transmission in accordance with predetermined shift conditions based on predetermined shift parameters such as a vehicle speed and an accelerator operation amount. When a predetermined automatic engine brake control condition such as an accelerator being in an OFF state is satisfied, an automatic engine including a downshift to an engine brake operation low speed stage is used instead of the shift control by the shift control means. 2. Description of the Related Art A shift control device for an automatic transmission including an automatic engine brake control unit that performs a brake control is known. For example, JP-A-1-193436
The automatic engine brake control disclosed in Japanese Patent Application Laid-Open No. H11-20964 is an example of this. When it is determined that the vehicle speed is increasing in a state where the accelerator is off and the vehicle speed is equal to or higher than the reference vehicle speed, the engine brake operation is automatically shifted to the low speed stage. It is designed to downshift.

[0003]

However, in such a shift control device for an automatic transmission, a predetermined automatic engine brake control condition is satisfied after the automatic engine brake control means downshifts to a low speed stage for operating the engine brake. When returning to normal shift control after disappearance, upshifting may be performed according to normal shift conditions even if the driver depresses the brake to decelerate the vehicle. For example, the shift determination in the normal shift control is performed in accordance with the shift map (for the first, second, third, and O / D four shift stages) shown in FIG. 9, and the control lower limit vehicle speed is 20 km as the automatic engine brake control condition. / H or more,
When the vehicle is decelerated by the driver's brake operation in a state where the vehicle is downshifted to 2nd by the automatic engine brake control and the vehicle speed falls below the lower limit vehicle speed and returns from the automatic engine brake control to the normal shift control, the shift map indicates that. Since it is in the 3rd area at the time, a 2 → 3 upshift is determined. When this upshift is performed, the engine braking force decreases compared to before the shift, and the driver is forced to step on the brakes in spite of requesting deceleration. There was an inconvenience of being damaged. In addition, since the downshift is performed when the vehicle speed further decreases, another problem that the driver feels a busy shift is included.

The present invention has been made in view of the above circumstances, and an object thereof is to prevent an upshift when a brake operation is being performed when returning from automatic engine brake control to normal shift control. It is in.

[0005]

In order to achieve the above object, it is only necessary to maintain the current gear when the brake is being operated when returning to the normal gear shift control.
As shown in the claim correspondence diagram of FIG.
An automatic transmission having a plurality of shift speeds, and (b) shift control means for changing a shift speed of the automatic transmission according to predetermined shift conditions based on predetermined shift parameters;
(C) The actual vehicle speed exceeds a predetermined reference vehicle speed
In this case, the shift control device of the automatic transmission includes an automatic engine brake control unit that performs an automatic engine brake control including a downshift to an engine brake operating low speed stage instead of the shift control by the shift control unit. (D) a brake sensor for detecting the presence or absence of a brake operation, and (e) an actual vehicle speed is equal to or less than the reference vehicle speed.
From the automatic engine brake control by the automatic engine brake control means based on the time of returning to the shift control by the shift control means, when it is in the braking operation is detected by the brake sensor, the Automatic shifting is performed until the shift control means determines that a downshift to the next lower gear is performed in accordance with the shift conditions.
Return limiting means for maintaining the gear position during engine brake control .

[0006]

In such a shift control device for an automatic transmission, the actual vehicle speed is equal to or lower than the reference vehicle speed.
When to wake from the automatic engine brake control to the shift control by the shift control means according to an automatic engine brake control means based on the fact that a lower, have been detected to be in braking operation by the brake sensor,
Until it is determined by the shift control means that a downshift to the next lower gear is performed in accordance with a predetermined shift condition , the shift speed under automatic engine brake control is held by the return limiting means. That is, even if an upshift is determined by the shift control means, the upshift is not performed during the brake operation. As a result, the upshift is performed in accordance with the shift conditions such as the shift map even while the brake operation is being performed, thereby preventing the engine braking effect from being reduced and meeting the intention of the driver who is performing the brake operation. Control is performed, and a busy shift in which an upshift and a downshift are performed in a short time is prevented.

On the other hand, since downshifting by the shift control means is permitted, re-acceleration after that and re-starting after the vehicle stops are performed quickly. In other words, if the current gear is held by prohibiting not only the upshift but also the downshift, the downshift must be performed to the predetermined gear when the accelerator is operated thereafter, so that the backlash and the engine air-blowing are reduced. It will happen.

[0008]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below in detail with reference to the drawings.

In FIG. 2, in a combustion chamber 12 of a gasoline engine 10, an air cleaner 14, an air flow meter 16, an intake passage 18, a throttle valve 20, a bypass passage 22, a surge tank 24, an intake manifold 26,
And air is sucked in through the intake valve 28,
A fuel gas injected from a fuel injection valve 30 provided in the intake manifold 26 is mixed with the air. The air flow meter 16 measures the amount of intake air, and outputs a signal indicating the amount of intake air to the computer 32 for engine control. Throttle valve 20
Is for continuously changing the amount of air sucked into the engine 10. The throttle valve opening .theta. Is controlled in accordance with a throttle control signal DTA supplied from a throttle control computer 35. The valve 20 is provided with a throttle position sensor 36, and outputs a throttle valve opening signal Sθ indicating the throttle valve opening θ to the engine control computer 32, the transmission control computer 34, and the throttle control computer 35. The throttle position sensor 36 has an idle switch function, and outputs an idle signal indicating that the throttle valve 20 is substantially fully closed to the computers 32, 34, and 35 together with the throttle valve opening signal Sθ. Bypass passage 2
2 is disposed in parallel with the throttle valve 20 and has an idle speed control valve 3
8 and an engine control computer 32
The opening degree of the idle speed control valve 38 is controlled by the control, whereby the amount of air flowing bypassing the throttle valve 20 is adjusted, and the engine speed during idling is controlled. The injection timing and injection amount of the fuel injection valve 30 are also controlled by the engine control computer 32. An intake air temperature sensor 40 for measuring the temperature of the intake air is provided upstream of the air flow meter 16, and a signal representing the intake air temperature is sent to an engine control computer 32.
Output to

The engine 10 includes an intake valve 28 and an exhaust valve 4
2, a piston 44, and a spark plug 46. The spark plug 46 generates an ignition spark by a high voltage supplied from an igniter 48 controlled by an engine control computer 32 via a distributor 50. The crankshaft is rotated by causing the mixed gas in the combustion chamber 12 to explode and move the piston 44 up and down. The intake valve 28 and the exhaust valve 42 are opened and closed by a cam shaft that is driven to rotate in synchronization with the rotation of the crankshaft, and is controlled by a variable valve timing mechanism (not shown) controlled by the engine control computer 32. The opening and closing timing is adjusted by changing the rotational phase of the camshaft and the crankshaft. The exhaust gas burned in the combustion chamber 12 is supplied from the exhaust valve 42 to the exhaust manifold 5.
4. The gas is discharged to the atmosphere via the exhaust passage 56 and the catalyst device 58. The engine 10 is provided with a water temperature sensor 60 that measures the temperature of the engine cooling water. The water temperature sensor 60 outputs a signal representing the temperature of the engine cooling water to the computer 32 for controlling the engine.
4 is an oxygen sensor 62 for detecting the oxygen concentration in the exhaust gas.
And outputs a signal indicating the oxygen concentration to the computer 32 for engine control. The distributor 50 is provided with a rotation angle sensor 51 that generates a pulse in synchronization with the rotation of the crankshaft, and outputs a pulse signal, that is, an engine rotation speed signal SNE representing the engine rotation speed NE, to the engine control computer 32 and the Output to the transmission control computer 34.

The computer 32 for engine control, the computer 34 for transmission control, and the computer 35 for throttle control are all CPU, RAM, R
The transmission control computer 34 includes an OM, an input / output interface circuit, an A / D converter, etc., and performs signal processing according to a program stored in the ROM while utilizing a temporary storage function of the RAM. Are the above signals, the pattern signal SP representing the selected pattern from the pattern select switch 70, the brake signal SB representing that the brake has been depressed from the brake lamp switch 72, and the overdrive switch 74 to the O / D gear. O / indicating the shift permission of
A D signal SO and an accelerator operation amount signal SAc representing the operation amount Ac of the accelerator pedal are supplied from the accelerator operation amount sensor 76, respectively. The accelerator operation amount signal SAc is also supplied to the computer 32 for engine control and the computer 35 for throttle control. The pattern select switch 70 has at least an automatic engine brake pattern for automatically increasing the engine brake on a downhill or the like, a power pattern for controlling the shift of the automatic transmission 78 by a shift map emphasizing the power performance, and a fuel efficiency. The driver selects and operates a favorite traveling pattern from a plurality of predetermined traveling patterns, such as an economy pattern in which gear shifting control is performed according to an emphasized shift map. The brake lamp switch 72 is provided near the brake pedal, and is configured by an ON-OFF switch or the like that is switched on and off depending on whether or not the driver has depressed the brake pedal.

The automatic transmission 78 includes a torque converter 110, a first transmission 112, and a second transmission 114, for example, as shown in FIG. The pump wheel of the torque converter 110 is connected to the crankshaft 118 of the engine 10, and the turbine wheel is connected to the input shaft 1.
20 is connected to the carrier 122 of the first transmission 112. The first transmission 112 includes a planetary gear unit including a sun gear 124, a ring gear 126, and a planetary gear 128 rotatably disposed on the carrier 122 and meshing with the sun gear 124 and the ring gear 126. 124 and carrier 1
22 and the clutch C ₀ and the one-way clutch F ₀
Are provided in parallel, the sun gear 124 and the housing 130
Brake B ₀ is provided between the.

The second transmission 114 is rotatably disposed on the sun gear 132, the pair of ring gears 134, 136, and the carrier 138, and is rotatable on the planetary gear 140 meshed with the sun gear 132, the ring gear 134, and the carrier 142. The planetary gear 1 disposed and engaged with the sun gear 132 and the ring gear 136
44, a clutch C ₁ is provided between the ring gear 136 and the ring gear 126 of the first transmission 112, and a clutch C ₁ is provided between the sun gear 132 and the ring gear 126. Has a clutch C
₂ is provided between the brake B ₁ represents between the sun gear 132 and the housing 130, and a one-way clutch F ₁ and the brake B ₂ which are disposed in series are provided in parallel, the carrier 138 and the housing 130 brake B ₃ and the one-way clutch F ₂ is provided in parallel to the. The ring gear 134 and the carrier 142 are connected to the output shaft 1.
The output shaft 146 is connected to drive wheels via a differential gear device or the like.

The clutches C ₀ -C ₂ and the brake B
_{0 to} B ₃ (hereinafter, unless otherwise specified, the clutch C,
The brake B) is a hydraulic friction engagement device that is controlled to be engaged by a hydraulic actuator such as a multi-plate clutch or a band brake so that hydraulic oil is supplied from a hydraulic control circuit 150 to the hydraulic actuator. Has become. The hydraulic control circuit 150 is provided with a number of switching valves and the like, and the solenoids S1, S2, and S3 are switched between energized and de-energized in accordance with signals from the transmission control computer 34, thereby switching the hydraulic circuit. The engagement of the clutch C and the brake B is selectively controlled, and one of the four forward speeds is established, as shown in FIG. In FIG. 4, the mark “○” in the column of solenoid means excitation, and the mark “○” in the column of clutch and brake means engagement. "D", "S",
"L" is the operating range of the shift lever in the driver's seat,
In the “D (drive)” range, shift control is performed in four steps from 1st to O / D. In the “S (second)” range, shift control is performed in two steps, 1st and 2nd.
In the (low) range, the gear is fixed to the first shift speed. Gear ratio i (= rotational speed N _O of the rotational speed N _T / output shaft 146 of the input shaft 120) is the largest in 1st, 2nd, 3r
It becomes smaller as d and O / D become, and the gear ratio of 3rd is 1.0. In the “D” range, the engine brake operates at 3rd and O / D, and the 1st and 2nd
At nd, although the engine brake does not work due to the action of the one-way clutches F ₂ and F ₁ , it is shown in parentheses (1).
st), (in 2nd), the brake B _3, B ₁ and is engaged engine braking by solenoid S3 each is excited is to act. The engine brake is also applied in the second range of the "S" range and the first range of the "L" range.

The automatic transmission 78 is provided with a pair of rotation speed sensors 80 and 82. The rotation speed sensor 80 is connected to the input shaft 120, that is, the torque converter 11.
Detects the rotational speed N _T of the turbine impeller of 0, the rotational speed sensor 82 is for detecting the rotational speed N _O of the output shaft 146, the rotational speed N _T, respectively, in a cycle corresponding to N _O pulse signal for generating a pulse, that is, the output rotational speed signal SN _T, the SN _O to the transmission control computer 34. Also, the hydraulic control circuit 15
0 is provided with a neutral start switch 84, and the "D", "S",
A shift range such as "L" or "R" is detected, and a shift range signal SR representing the shift range is output to the transmission control computer 34. The hydraulic control circuit 150 is also provided with an oil temperature sensor 86 for detecting the oil temperature (A / T oil temperature) THO of the hydraulic oil, and the A / T oil temperature T
An oil temperature signal STHO representing HO is output to the transmission control computer 34. In addition, necessary information is exchanged between the control computers 32, 34, 35.

The engine control computer 32 calculates the intake air amount, the throttle valve opening θ, the engine speed NE, the cooling water temperature of the engine 10, the intake air temperature, the oxygen concentration in the exhaust passage 56, and the accelerator operation. Amount Ac
In accordance with, for example, the fuel injection valve 3 based on a data map or an arithmetic expression determined in advance to reduce fuel consumption and harmful exhaust gas while securing necessary engine output,
It controls the fuel gas injection amount and injection timing by 0, the ignition timing by the igniter 48, the idle speed by the idle speed control valve 38, and the opening and closing timing of the intake and exhaust valves 28 and 42 by the variable valve timing mechanism. The transmission control computer 34 controls the throttle valve opening θ, the engine speed NE, the selection pattern represented by the pattern signal SP, the presence / absence of the brake operation represented by the brake signal SB, and the O / D shift speed represented by the O / D signal SO. Whether or not a shift can be performed, accelerator operation amount Ac, automatic transmission 78
Based like the output shaft rotation speed N _O of the solenoid S
By switching between excitation and non-excitation of S1, S2, and S3, the shift speed of the automatic transmission 78 is switched. The transmission control computer 34 also controls the throttle valve opening θ of the throttle valve 20 according to the accelerator operation amount Ac, or adjusts the throttle valve opening θ when the accelerator operation amount Ac is zero to adjust the engine braking force. , The throttle command signal SQ is output to the throttle control computer 35. The throttle control computer 35 basically outputs a throttle control signal DTA for controlling the throttle valve opening θ in accordance with the throttle command signal SQ.

The shift control and the throttle control by the transmission control computer 34 will be specifically described below with reference to the flowcharts of FIGS. The flowcharts of FIGS. 5 and 6 relate to shift control for switching the gear position of the automatic transmission 78, and the flowcharts of FIGS. 7 and 8 relate to throttle control. In addition, such control is, for example, 8 to
It is repeatedly executed with a cycle time of about 32 msec.

In step S1 of FIG. 5, when the automatic engine brake control is executed, step S1 of FIG.
It is determined whether or not the flag F3 set to "1" in E2 is "1". If F3 = 0, step S2 is executed.
In step S2, a normal shift determination is made as to whether or not to change the shift speed of the automatic transmission 78. The current shift speed and accelerator operation amount A are determined based on a shift map as shown in FIG.
with obtaining the shift-up vehicle speed Vu and downshift vehicle speed Vd based on c, and the rotational speed signal SN _O current vehicle speed V and the corresponding output shaft rotation speed N _O representing a shift-up vehicle speed Vu and downshift vehicle speed Vd Compare. The shift-up vehicle speed Vu and the shift-down vehicle speed Vd illustrated in FIG. 9 are obtained when the accelerator operation amount Ac is about 40% and the current gear is 3rd. Further, the current gear position is determined from the output state of the excitation signal for exciting the solenoids S1, S2, S3. If V> Vu, an upshift is determined, and if V ≦ Vd, a downshift is determined, and the next shift speed to be shifted is set according to this determination.

In the following steps S3 and S4, it is determined whether the shift is an upshift or a downshift, respectively.
If it is an upshift, the flag F1 is set in step S5.
Is set to "1", and when downshifting is performed, the flag F2 is set to "1" in step S6. When both are denied, the flag F1 and the flag F2 are set to "0" in step S8. Is done. If it is an upshift or a downshift, the shift timing time T1 is set in step S7. The shift timing time T1 is a delay time from when a shift determination is made to when a shift output is performed to actually switch the shift stage (step S30 in FIG. 6). (Multiple shifts) is prevented and the upshift is actually performed even if an upshift to the O / D shift stage is made when the accelerator pedal is quickly released to apply the engine brake on a downhill. Before the operation, when the accelerator operation amount Ac becomes substantially zero,
It is provided to prohibit an upshift to the O / D gear.

If step S1 is YES, that is, if the automatic engine brake control is executed and the flag F3 is set to "1", step S9 is executed and it is determined whether or not the flag F5 is "0". I do. The flag F5 is set to "1" in step SE14 in FIG. 8 when the automatic engine brake control is executed and the brake is depressed, and when the flag F5 = 1, the step S12 is performed.
Is executed, and a downshift vehicle speed Ved during engine braking is obtained from a predetermined downshift map during engine braking. The downshift map at the time of engine braking is determined for each type of shift so that the downshift is performed on a higher vehicle speed side than normal (downshift map indicated by a broken line in FIG. 9) within a range where the engine 10 does not overrun. . In the next step S13, the current vehicle speed V is compared with the downshift vehicle speed Ved to determine whether or not to downshift. If V> Ved, step S
8 and the shift determination is ended. If V ≦ Ved, in step S14, a shift speed lower than the current shift speed is set as the next shift speed. The gear position set here is the one where the engine brake works, and 2nd
Alternatively, in the first stage, the gear position (the solenoid S3 is ON) shown in parentheses in FIG. 4 is set. Thereafter, the flag F2 is set to "1" in step S15.

In step S10 executed when the brake is not depressed in the automatic engine brake control, it is determined whether or not a flag F4 is "1". The flag F4 is set to “1” in step SE12 of FIG. 8 when downshifting is performed to increase the engine braking force.
If F4 = 0, the above-described step S
8 and the process ends, but if F4 = 1, step S
11 is executed, and the next low gear (the solenoid S3 is ON in the case of 2nd or 1st) is set as the next gear under the condition that the engine 10 does not overrun. Step S11 or S
When the next gear position is set in step 14,
At 7, a shift timing time T1 is set.

Next, the flow chart of FIG. 6 for actually changing the gear position will be described. In step S20, it is determined whether or not the flag F1 is "1", that is, whether or not an upshift has been determined. If the flag F1 is "1", the steps from step S21 are executed. Otherwise, step S36 is executed. In step S36, it is determined whether or not the flag F2 is "1", that is, whether or not the downshift is in accordance with the shift map. If the flag F2 is "1", the steps from step S28 are executed. If the flag F2 is not "1", step S37 is executed, and it is determined whether or not the flag F4 is "1", that is, whether or not the downshift is performed to increase the engine braking force. In this case, each step from step S21 is executed, but otherwise, step S32 is executed and the processing ends.

In step S21, the shift range signal SR
Is determined to be "D (drive)", and in step S22, the accelerator is OFF, that is, the accelerator operation amount Ac indicated by the accelerator operation amount signal SAc.
Is substantially zero, specifically, taking into account a detection error and the like.
In step S23, it is determined whether or not the running pattern represented by the pattern signal SP is an "automatic engine braking pattern".
At 24, it is determined whether or not the current vehicle speed V is higher than a predetermined lower limit vehicle speed V1, and at step S25, it is determined whether or not the current vehicle speed V is lower than or equal to a predetermined upper limit vehicle speed V2. It is determined whether the next gear set in step S2 is an O / D gear. The lower limit vehicle speed V1 and the upper limit vehicle speed V2 define a vehicle speed range in which special control for automatically increasing the engine braking force is performed. The lower limit vehicle speed V1 is set to, for example, about 20 km / h, and the upper limit vehicle speed V2 is set to, for example, 110 km. / H. Then, the determinations in steps S21 to S26 are all Y
In the case of ES, after the next gear position is changed to “3rd” in step S27, steps S29 and the subsequent steps are executed. If any one of steps S21 to S26 except for step S24 is NO, step S27 is executed. In S28, steps S29 and subsequent steps are executed without the change of the next shift speed in step S27. Step S26
Is to determine whether or not the next gear set in step S2 is an O / D gear.
Thus, the determination is YES also in the cycle after the next gear is changed to "3rd". If the determinations in steps S21 to S23 are YES and the determination in step S24 is NO,
Step S33 and subsequent steps are executed.

In step S29, it is determined whether or not the time counted by the timer Ta is equal to or longer than the shift timing time T1. Step S20 and subsequent steps are repeated until the shift timing time T1 is reached. When the shift timing time T1 is reached, step S30 is executed, and the solenoids S1 and S1 are executed.
By switching between excitation and non-excitation in S2 and S3, the gear position of the automatic transmission 78 is switched to the next gear position set in steps S2, S11 and S14, or to the 3rd gear position changed in step S27. After the shift, the flags F1, F2, F4, and F6 are set to "0" in step S31, and the timer Ta is reset in step S32. This timer Ta measures the elapsed time after the next gear is set in step S2, S11, or S14.

In a step S33 executed when the judgment in the step S24 is NO, it is judged whether or not the flag F6 is "1". In a step S34, based on the brake signal SB from the brake lamp switch 72, ,
It is determined whether or not the driver has depressed the brake. The flag F6 is set to "1" in step SS12 of FIG. 7 when the vehicle speed V falls below the lower limit vehicle speed V1 during the automatic engine brake control. If either one of the determinations in steps S33 and S34 is NO, step S28 and subsequent steps are executed. If both conditions are satisfied, step S35 is executed and the flag F1 indicating the upshift is set to "0". ". That is, even if the vehicle speed V becomes equal to or lower than the lower limit vehicle speed V1 during the automatic engine brake control and the vehicle speed V becomes equal to or lower than the lower limit vehicle speed V1 and the normal shift determination in step S2 is performed and the upshift is determined, the upshift is performed. It is prohibited and the current gear is maintained.

Next, the throttle control during the automatic engine brake control will be described. First, in steps SS1 to SS5 in FIG. 7, the shift range, the accelerator operation amount Ac, the running pattern, and the vehicle speed V are the same as those in steps S21 to S25. If all the conditions are satisfied, an automatic engine brake throttle processing routine of step SS6 is executed. In the present embodiment, it is a predetermined automatic engine brake control condition that all the determinations in steps SS1 to SS5 are YES.

FIG. 8 is a flowchart showing an example of the contents of the above-mentioned automatic engine brake throttle processing routine. In step SE1, it is determined whether or not the flag F3 is "1". If the flag F3 = 0, the flag F3 is set to "1" in step SE2, and normal throttle control is performed in step SE3. Flag F
By setting “3” to “1”, step S in FIG.
The determination at 1 is YES, the normal shift determination at step S2 is prohibited, and steps S9 and thereafter are executed. In the normal throttle control in step SE3, the throttle valve opening TA (Ac) is obtained from a predetermined map or an arithmetic expression based on the accelerator operation amount Ac indicated by the accelerator operation amount signal SAc, and the throttle valve opening TA is obtained.
(Ac) is set to the target throttle valve opening TA, and a throttle command signal SQ indicating the target throttle valve opening TA is output to the throttle control computer 35. The throttle control computer 35 controls the throttle control so that the actual throttle valve opening θ of the throttle valve 20 matches the target throttle valve opening TA indicated by the throttle command signal SQ, that is, TA (Ac) by feedback control or the like. Send signal DTA to throttle valve 2
Output to 0. In the automatic engine brake control, since the accelerator operation amount Ac is substantially zero, the throttle valve 20 is fully closed.

In the following step SE4, the vehicle speed V at that time is set to the target vehicle speed Vm. Step SE2 above
In the cycle after the flag F3 is set to "1" in step S5, step SE5 is executed following step SE1.
The vehicle speed (Vm-Vf) obtained by subtracting a predetermined constant value Vf from the target vehicle speed Vm is compared with the vehicle speed V at that time.
If V> (Vm−Vf), step SE6 and subsequent steps are executed, but if V ≦ (Vm−Vf), step SE is executed again.
4 and the target vehicle speed Vm is changed to the vehicle speed V at that time. The above constant value Vf
In consideration of the fluctuation of the vehicle speed V due to the feedback control of the throttle valve opening θ in step SE11, the fluctuation does not result in NO in step SE5.
The target vehicle speed Vm is determined to be updated in step SE4 when the vehicle speed V decreases relatively significantly due to a brake depression operation or the like.

In step SE6, the brake signal S
It is determined whether or not the brake is depressed based on B. If the brake is off, that is, if the depressed operation is not performed, the steps from step SE7 are executed. However, the driver depresses the brake in order to further decelerate. Then, the determination in step SE6 is NO, and steps SE14 and SE15 are executed. In step SE14, the flag F
5 is set to "1", and in step SE15, the target throttle valve opening TA is set to the throttle valve opening TA (Ac), that is, zero in order to increase the engine braking force, and represents the target throttle valve opening TA. By outputting the throttle command signal SQ to the throttle control computer 35, the throttle valve 20 is fully closed. When the flag F5 is set to "1", the determination in step S9 in FIG. 5 becomes NO, and the shift control is performed according to the downshift map during engine braking.

Step SE executed when brake is off
At 7, it is determined whether or not the flag F5 is "1". If YES, steps SE8 and thereafter are executed. At step SE8, the flag F5 is set to "0", and at step S8.
In step E9, the target vehicle speed Vm is changed to the vehicle speed V at that time, as in step SE4. That is, the target vehicle speed Vm is updated when the brake changes from ON to OFF. In step SE10 executed when the flag F5 is not “1”, it is determined whether or not the throttle valve opening θ is smaller than a predetermined determination value θ1. The determination value θ1 is a small value of about 1.5% or less, and is determined based on an idle signal indicating that the throttle valve 20 is substantially fully closed. And when θ> θ1,
That is, when the engine braking force can be increased by closing the throttle valve 20, step SE11 is executed, and the vehicle speed V is substantially equal to the target vehicle speed Vm in accordance with the deviation between the target vehicle speed Vm and the current vehicle speed V. The throttle valve opening TA1 (%) for matching is set to the well-known P
The throttle valve opening TA1 is calculated according to an arithmetic expression of feedback control such as an ID operation, and the target throttle valve opening TA is set.

When the throttle valve 20 is substantially fully closed and it is impossible to increase the engine braking force in the throttle control in step SE11, specifically, the determination in step SE10 becomes YES, and the state becomes a predetermined value. If the time or predetermined cycle continues,
At step SE12, the flag F4 is set to "1", and then step SE13 is executed. By setting the flag F4 to “1”, the determination in step S10 in FIG.
ES is set, and the next shift speed at which the engine braking action is obtained is set in step S11. In step SE13, the throttle valve opening TA2 (%) at which substantially the same driving force can be obtained before and after the downshift, based on the type of downshift and the current vehicle speed V, is shown in, for example, FIG. Is calculated from a predetermined data map, and the throttle valve opening TA2 is set to the target throttle valve opening TA, and the throttle command signal SQ representing the target throttle valve opening TA is controlled by the throttle control. The throttle valve 20 is controlled so that the actual throttle valve opening θ of the throttle valve 20 becomes the throttle valve opening TA2. The data map shown in FIG. 10 is based on the driving force data obtained experimentally in advance, and based on the driving force when the throttle valve 20 is fully closed at the shift speed before the downshift (in this case, the driving force is a negative value. (Acting as a braking force), or a negative driving force that causes the engine braking force to be the same or slightly larger, changes the throttle valve opening TA2 (%) obtained even after a downshift, This is obtained for each type and vehicle speed.

Returning to FIG. 7, if any one of the determinations excluding step SS4 from steps SS1 to SS5 is NO, the flag F6 is set to "0" in step SS7.
And at step SS8, the flag F3,
The flag F4 and the flag F5 are each set to “0”,
In the following step SS9, normal throttle control is performed in the same manner as in step SE3, the throttle valve opening TA (Ac) obtained based on the accelerator operation amount Ac is set to the target throttle valve opening TA, and a throttle command representing the target throttle valve opening TA is set. The signal SQ is output to the throttle control computer 35. On the other hand, if the determination in step SS4 is NO, step SS10 and subsequent steps are executed. In step SS10, it is determined whether or not the flag F6 is "1", and in step SS11, it is determined whether or not the flag F3 is "1". If either of the flag F6 and the flag F3 is "1", the step SS12 is executed, and after the flag F6 is set to "1", steps SS8 and subsequent steps are executed, while both the flag F6 and the flag F3 are "1". If not, the process from step SS7 is executed.

That is, an automatic engine brake throttle processing routine of step SS6 is executed, and the flag F3
Is set to "1", if the vehicle speed V decreases due to the brake operation, becomes equal to or lower than the control lower limit vehicle speed V1, and the determination in step SS4 is NO, the process proceeds to step S4.
The flag F6 is set to "1" in S12. Therefore, the flag F3 is set to “0” in step SS8, and FIG.
The normal shift determination in step S2 is performed following step S1 in FIG. 6, and an upshift determination is made in step S2, followed by steps S20 to S24 in FIG.
When Step 33 has been executed, the judgment is YES, and Step S34 is executed. At this time, if the brake is depressed, the determination in step S34 is also YES, upshifting is prohibited, and the current gear position is maintained. Thus, for example, the vehicle is decelerated by the driver's brake operation in the state of being downshifted to 2nd by the automatic engine brake control in step SS6, becomes lower than the control lower limit vehicle speed V1, and returns to the normal shift control from the automatic engine brake control. When the shift map
By entering the rd region, a 2 → 3 upshift is performed and the engine braking force is prevented from decreasing compared to before the shift.

As described above, in the shift control of the present embodiment, when the vehicle speed V becomes equal to or lower than the control lower limit vehicle speed V1 to return from the automatic engine brake control to the normal shift control, the brake is depressed. In step S2
Even if an upshift is made, the execution is prevented, so that the engine braking force is prevented from lowering due to the upshift, and the control that matches the intention of the driver performing the brake operation is performed. Become.

On the other hand, as the vehicle speed V decreases, step S2
If a downshift is determined in step S36, the determination in step S36 in FIG. 6 is YES, and steps S28 and subsequent steps are executed, and a downshift is performed in step S30.
For this reason, when the accelerator is subsequently depressed to re-accelerate or when the vehicle restarts after stopping, as in the case of being held at the intermediate gear position,
The downshift to the predetermined gear position does not cause the backlash due to acceleration or the idling of the engine 10. Further, since the upshift is prohibited during the brake operation as described above, a busy shift in which the upshift and the downshift are performed in a short time as the vehicle speed V decreases does not occur.

In this embodiment, the part of the series of signal processing performed by the transmission control computer 34 that executes steps S2 and S30 corresponds to the shift control means, and executes steps S1, S9 to S14, S30 and step SS6. This portion, together with the throttle control computer 35, constitutes automatic engine brake control means. In addition, a portion that executes steps S33, S34, and step SS12 corresponds to a return limiting unit, and the brake lamp switch 72 corresponds to a brake sensor.

Next, another embodiment of the present invention will be described with reference to FIG.
This will be described with reference to FIGS. FIG.
Steps SS20 to S20 in place of step SS6 in a mode in which some of the steps in the flowchart of FIG.
S23 is provided. In step SS20, which is executed when all the determinations in steps SS1 to SS5 are YES, it is determined whether or not the flag F3 is "1". When the flag F3 is "0", the reference acceleration G1 is determined in step SS21. Set. The reference acceleration G1 is an acceleration when the throttle valve opening θ = 0 at a predetermined downward gradient, and the vehicle speed V and the shift speed at that time are set as parameters. After the execution of step SS21 or the flag F3
In the case of = 1, step SS20 is followed by step SS
Step 22 is executed to determine whether or not the acceleration G of the vehicle is equal to or higher than the reference acceleration G1.

The acceleration G is calculated for each pulse of the rotation speed signal SN _O output from the rotation speed sensor 82 according to, for example, a flowchart shown in FIG. 12. First, at step SG1, the pulse of the rotation speed signal SN _O is calculated. The cycle _Ti is calculated, and the next pulse cycle Ti _-1 is read in the next step SG2. In step SG3,
The acceleration G is calculated by multiplying (T _i−1 −T _i ) / T _i−1 by a predetermined coefficient f, and the current pulse period T _i is stored as T _i−1 in step SG4. When the acceleration G is equal to or higher than the reference acceleration G1, that is, when the inclination is greater than the predetermined downward gradient,
An automatic engine brake throttle processing routine of step SS23 is executed. In this embodiment, step SS
YES in step SS22 in addition to 1 to SS5
Is an automatic engine brake control condition.

FIG. 13 is a flowchart showing an example of the contents of the automatic engine brake throttle processing routine in step SS23, which is partially different from the control routine of FIG. After setting the flag F3 to "1" in step SE2, it is determined in step SE6 whether or not a brake operation has been performed. If the brake is off, that is, if the stepping operation has not been performed, step SE8 and subsequent steps are executed. Steps SE14 and SE15 are executed in the same manner as described above. After the flag F5 is set to "0" in step SE8, it is determined in step SE10 whether or not the throttle valve opening θ is equal to or smaller than the determination value θ1, and if θ> θ1, step SE20 is executed. Step SE2
In the case of 0, a predetermined constant amount ΔTA is subtracted from the previous target throttle valve opening TA to update the target throttle valve opening TA to a new target throttle valve opening TA, and the throttle command signal SQ representing the same is updated.
To the throttle control computer 35, the throttle valve 20 is controlled such that the throttle valve opening θ is reduced by a fixed amount ΔTA, and the engine braking force is increased accordingly. Such a step SE
As the engine braking force is increased by the throttle control at 20, the increase in the vehicle speed V is suppressed, and the acceleration G
Is smaller than the reference acceleration G1, the step SS2
The determination of 2 is NO, and the throttle valve opening θ at that time is maintained.

FIG. 14 is a flowchart showing step SS2 in FIG.
Step SS2 provided in place of SS1, SS22
6, SS27, and the reference running resistance coefficient S1
And the actual running resistance coefficient S, and S ≦ S1 is set as an automatic engine brake control condition.
The running resistance coefficient S in step SS27 is calculated, for example, in step SG5 shown in FIG. 15, and this step SG5 is provided and executed between step SG3 and step SG4 in FIG. . In step SG5, a value obtained by dividing the acceleration G by a reference acceleration G2 when the throttle valve opening θ is 0 on a flat road is calculated as the running resistance coefficient S.
The reference acceleration G2 has a negative value due to the air resistance and the rolling resistance, while the acceleration G increases as the descending slope increases and becomes a positive value in a situation where engine braking is to be considered. The coefficient S decreases as the slope of the downhill slope increases. The reference acceleration G2 is set in advance using the vehicle speed V and the shift speed as parameters. Further, the reference running resistance coefficient S1 set in step SS26 is a running resistance coefficient at a predetermined down slope, that is, the acceleration G when the throttle valve opening θ = 0 at the predetermined down slope is the reference acceleration G2 on a flat road. This is a value obtained by division, and the vehicle speed V and the shift speed are set as parameters. Therefore, if S ≦ S1, it means that the gradient is greater than the above-mentioned predetermined downward gradient, and in that case, the automatic engine brake control is started.

Although the embodiments of the present invention have been described in detail with reference to the drawings, the present invention can be embodied in other forms.

For example, in the above-described embodiment, the brake lamp switch 72 provided near the brake pedal functions as a brake sensor. The detecting means may be provided as a brake sensor.

Further, in the above embodiment, step S in FIG.
In S11, it is determined whether the return from the automatic engine brake control to the normal shift control is performed by determining whether or not the flag F3 is "1". However, the downshift to the engine brake operating low speed is performed. Is determined by using other flags or the like.
In step 2, the flag F6 may be set to "1".

In the above embodiment, the flag F6 is set to "1" when the vehicle speed V falls below the lower limit vehicle speed V1 and the automatic engine brake control is released.
When the automatic engine brake control is cancelled, the flag F6 is always set to "1". When the upshift is determined in step S2 and the flag F1 is set to "1", the process always proceeds to step S33. The control may be executed to prohibit the upshift during the brake operation.

For example, when the automatic engine brake control is performed on the condition that the road surface gradient is equal to or more than a predetermined downward gradient, the brake is not applied when the condition of the road surface gradient is not satisfied and the automatic engine brake control is released. When the vehicle is being operated, it is desirable to prohibit the upshift as in the case where the vehicle speed V becomes equal to or lower than the lower limit vehicle speed V1 and the automatic engine brake control is released.

In the above-described embodiment, when the upshift is executed, the steps from step S33 are executed, and the flag F6 is set to "1".
And when the brake operation is being performed, the upshift is prohibited. However, if step S3 in FIG. 5 is YES, steps S33 and S34 are executed, and both determinations are Y.
In the case of ES, the process may proceed to step S8 to inhibit the upshift. Flag F6 is "1"
In the case where the brake operation is being performed, the determination itself as to whether or not to perform the upshift may not be performed.

Further, in the above-described embodiment, the case of the automatic transmission 78 having four forward gears has been described. However, the number of gears and the type of downshift by automatic engine brake control can be changed as appropriate. For example, if the vehicle has five or more forward gears, the automatic engine brake control performs “5
→ 4 ”It is also possible to perform a downshift.

In the above-described embodiment, the automatic engine brake control is executed only in the "D" range. However, the automatic engine brake control can be executed also in the "S" range. In this case, the present invention can be similarly applied.

In the above embodiment, the accelerator is in the OFF state, the automatic engine braking control pattern is satisfied, the lower limit vehicle speed V1 <the vehicle speed V ≦ the upper limit vehicle speed V2, the “D” range, the acceleration G ≧ Reference acceleration G
1, running resistance coefficient S ≦ reference running resistance coefficient S1
Has been defined as a condition for executing the automatic engine brake control, but for example, the acceleration G is equal to or higher than a predetermined reference acceleration, and the road surface gradient detected by the inclination angle sensor or the like is Other conditions, such as being equal to or greater than a certain downward slope, may be determined, or any of the above conditions may be combined or omitted. The condition for starting the automatic engine brake control and the condition for releasing the automatic engine brake control can be set separately.

In the above-described embodiment, step S is executed in the automatic engine brake throttle control routine shown in FIG.
If the determination in E10 is affirmative, the throttle control is performed in step SE13 so that the driving force before and after the gear shift becomes substantially equal. In this case, the opening amount of the throttle valve 20 is appropriately determined, and the throttle valve 20 is controlled. The downshift may be performed with fully closed.

Further, in the above-described embodiment, step SE1 is performed.
Although the throttle control is performed in SE1, SE13, and SE20, it is also possible to control the output of the engine 10 by opening the idle speed control valve 38 or using an engine accessory such as an alternator.

In the first embodiment, the actual vehicle speed V
And the target vehicle speed Vm, the throttle valve 20 is feedback-controlled. For example, the throttle valve opening is increased or decreased by a predetermined amount depending on whether the vehicle speed V is higher or lower than the target vehicle speed Vm. Is also good.

In the first embodiment, the accelerator OF
The vehicle speed V at the time of F or brake release is the target vehicle speed Vm
However, the target vehicle speed Vm does not need to completely match such a vehicle speed V, and a predetermined value is added to or subtracted from the vehicle speed V in consideration of a measurement error or the like. The vehicle speed Vm may be set, or the driver may arbitrarily set or change the target vehicle speed Vm.

In the above-described embodiment, the vehicle in which the throttle valve opening θ is always controlled by the throttle control computer 35 has been described. However, the throttle valve 20 is mechanically connected to the accelerator pedal to open and close. The present invention is also applicable to a vehicle in which the throttle valve 20 is automatically opened and closed only when the accelerator is off.

In the above-described embodiment, the engine control computer 32, the transmission control computer 34, and the throttle control computer 35 are formed separately, but they may be formed by a single computer. It is possible.

Although not specifically exemplified, the present invention can be embodied with various modifications and improvements based on the knowledge of those skilled in the art.

[Brief description of the drawings]

FIG. 1 is a diagram corresponding to claims of the present invention.

FIG. 2 is a diagram illustrating a configuration of an automatic transmission and an engine of a vehicle including a control device for an automatic transmission according to an embodiment of the present invention.

FIG. 3 is a diagram illustrating a configuration of the automatic transmission of FIG. 2;

FIG. 4 is a diagram showing a shift speed of the automatic transmission shown in FIG. 3, an excitation of a solenoid for establishing the shift speed, and an engagement operation of a clutch and a brake.

FIG. 5 is a flowchart illustrating an operation of a shift determination of whether or not to change the gear position of the automatic transmission of FIG. 2;

FIG. 6 is a flowchart illustrating an operation of a shift control for switching a shift speed of the automatic transmission of FIG. 2;

FIG. 7 is a flowchart illustrating an operation of controlling the throttle valve opening of the engine of FIG. 2;

FIG. 8 is a flowchart illustrating control of an automatic engine brake throttle processing routine in step SS6 of FIG. 7;

FIG. 9 is an example of a shift map for switching a shift speed of the automatic transmission of FIG. 2;

FIG. 10 is an example of a data map used for obtaining a throttle valve opening TA2 in step SE13 of FIG. 6;

FIG. 11 is a flowchart for explaining another embodiment of the present invention, and illustrating a mode in which a condition based on acceleration G is added to an automatic engine brake control condition.

FIG. 12 is an example of a flowchart for explaining specific contents when obtaining an acceleration G in step SS22 of FIG. 11;

FIG. 13 is a flowchart illustrating control of an automatic engine brake throttle processing routine in step SS23 of FIG. 11;

FIG. 14 is a diagram showing steps provided in place of steps SS21 and SS22 in FIG. 11;

FIG. 15 shows a running resistance coefficient S in step SS27 of FIG.
FIG. 13 is a diagram showing a step additionally provided between steps SG3 and SG4 in FIG. 12 in order to obtain.

[Explanation of symbols]

34: Transmission control computer 35: Throttle control computer 72: Brake lamp switch (brake sensor) 78: Automatic transmission Steps S1, S9 to S14, S30, SS6, SS2
3: Automatic engine brake control means Steps S2, S30: Shift control means Steps S33, 34, SS12: Return restriction means Steps SS1 to SS5, SS22, SS27: Automatic engine brake control conditions

──────────────────────────────────────────────────続 き Continuation of the front page (72) Inventor Kazumi Hoshiya 1 Toyota Town, Toyota City, Aichi Prefecture Inside Toyota Motor Corporation (56) References JP-A 1-261547 (JP, A) (58) Survey Field (Int.Cl. ⁶ , DB name) F16H 59/00-61/12 F16H 61/16-61/24 F16H 63/40-63/48

Claims (1)

(57) [Claims] And 1. A automatic transmission having a plurality of gear stages, a shift control means for changing the gear position of the automatic transmission in accordance with a predetermined shift condition based on a predetermined shift parameters, the actual vehicle speed in advance An automatic engine brake control means for performing an automatic engine brake control including a downshift to a low speed gear for operating an engine brake in place of the shift control by the shift control means when the vehicle speed exceeds a predetermined judgment reference vehicle speed; A shift control device for an automatic transmission, comprising: a brake sensor for detecting the presence or absence of a brake operation; and a brake sensor for determining whether an actual vehicle speed is equal to or less than the determination reference vehicle speed.
When returning to the shift control by the shift control means from an automatic engine brake control by the automatic engine brake control means have, when said that by the brake sensor is in the braking operation is detected, the shift
Automatic engine braking until the control means determines that the downshift to the next lower gear is performed in accordance with the shift conditions.
A shift control device for an automatic transmission, comprising: a return restricting unit that holds a shift speed during key control .