JPH05196136A - Speed change control device for automatic transmission - Google Patents

Abstract

PURPOSE:To prevent up-shift from occurring along with decrease of acceleration control input at the time of releasing an acceleration pedal to operate engine braking on a downward slope. CONSTITUTION:Even when up-shift judgement to an O/D speed change step is made, practice of a step S30 to carry out actual changeover of the speed change step 18 postponed until speed change timing T1 passes. In the case when everything is satisfied under the conditions of steps S21-S26 including acceleration OFF during that time, a following step is changed over to 3rd by a step S27, and up-shift to the O/D speed change step is prohibited.

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 an improvement in shift control when the accelerator is turned off on a downhill or the like.

[0002]

2. Description of the Related Art Generally, an automatic transmission of a vehicle is designed so that a shift stage can be switched based on an accelerator operation amount or a throttle valve opening and a vehicle speed. FIG. 7 is an example of a shift map (shift conditions) of an automatic transmission having four shift stages. The shift stages can be switched based on the accelerator operation amount and the vehicle speed, and the solid line indicates the shift on the upshift side. In the map, the broken line is the shift map on the downshift side. Such a shift map is usually designed to upshift depending on the vehicle speed even when the accelerator operation amount is zero, that is, in the OFF state. Therefore, even when the accelerator pedal is released on a downhill, sufficient engine braking force is obtained. If the vehicle speed increases without being obtained, there is a problem that the engine braking force further decreases due to an upshift. As a countermeasure against this, it is considered that even if the upshift is determined according to the shift map, the upshift is prohibited when the accelerator is in the OFF state to prevent the engine braking force from decreasing. JP-A-63-30825
The device described in Japanese Patent Publication No. 8 is an example.

[0003]

However, as is clear from FIG. 7, the above-mentioned conventional shift map is determined so that the smaller the accelerator operation amount is, the higher the speed is when the vehicle speed is the same. When the accelerator pedal is released on a downhill, an upshift may be performed in the process of decreasing the accelerator operation amount. Prohibiting the upshift when the accelerator is off does not always lead to proper engine brake control. was there. For example, at point A in FIG. 7, the shift speed is 2nd or 3rd, but if the accelerator pedal is released from that state,
Since the accelerator operation amount becomes zero across the “2 → 3” upshift line and the “3 → O / D” upshift line, it is possible to judge the shift to the O / D shift stage before the accelerator operation amount becomes zero. At the time of the determination, the accelerator operation amount is not zero yet, and the upshift to the O / D gear stage is permitted.

The present invention has been made in view of the above circumstances. An object of the present invention is to provide a proper engine braking force even when an upshift is determined before the accelerator operation amount becomes zero. The shift control is performed so that

[0005]

In order to achieve the above object, if the accelerator operation amount becomes zero within a predetermined time after the upshift is judged, the upshift is prohibited. According to the present invention, as shown in the claim correspondence diagram of FIG. 1, (a) an automatic transmission having a plurality of shift stages, and (b) the accelerator shift amount becomes smaller, the shift stage becomes smaller. Shift determining means for determining whether or not the shift stage of the automatic transmission is to be upshifted on the basis of a shift condition predetermined to upshift to a higher speed side, and (c) determination of the shift determining means. A shift control device for an automatic transmission, comprising: a switching means for upshifting a shift speed of the automatic transmission according to a result; (d) switching the shift speed by the switching means from the time when the shift judging means judges; Predetermined Delay means for delaying by a predetermined delay time, and (e) at least the maximum when the accelerator operation amount is equal to or less than a predetermined value of substantially zero before the shift stage is switched by the switching means. Upshift inhibiting means for inhibiting upshifting to a high speed stage is provided.

[0006]

In such a shift control device for an automatic transmission, the delay means determines in advance from the time when the shift judgment means makes the upshift shift judgment until the switching means actually changes the shift speed. When the accelerator operation amount becomes equal to or less than a predetermined value of substantially zero during the provided delay time, the upshift prohibiting means prohibits upshift to at least the highest speed stage. For this reason, if the driver releases the accelerator on a downhill or the like because he / she does not want to increase the speed any further, even if the upshift is judged due to the decrease in the accelerator operation amount, the accelerator operation is performed in a short time after that. When the amount becomes substantially zero, the upshift prohibiting means prohibits at least the upshift to the highest speed stage, and the engine braking force is prevented from being lowered due to the upshift. Further, even when the vehicle speed rises when the accelerator operation amount is substantially zero and the upshift is determined, the upshift to at least the highest speed stage is prohibited by the upshift inhibiting means.

[0007]

As described above, according to the shift control device for an automatic transmission of the present invention, when the accelerator operation amount becomes substantially zero within a predetermined delay time after the upshift shift determination is made. Since at least the upshift to the highest speed stage is prohibited, the decrease in engine braking force due to the upshift can be favorably avoided.

[0008]

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

In FIG. 2, in the combustion chamber 12 of the 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 taken in through the intake valve 28,
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 intake air amount, and outputs a signal indicating the intake air amount to the engine control computer 32. Throttle valve 20
Is for continuously changing the amount of air taken into the engine 10. The throttle valve opening θ is controlled according to the throttle control signal DTH supplied from the throttle control computer 35, and the throttle The valve 20 is provided with a throttle position sensor 36, and outputs a throttle valve opening signal Sθ representing the throttle valve opening θ to the engine control computer 32, the transmission control computer 34, and the throttle control computer 35. Bypass passage 2
2 is arranged in parallel with the throttle valve 20, and the idle speed control valve 3 is provided in its bypass passage 22.
8 is provided, and an engine control computer 32
By controlling the opening degree of the idle speed control valve 38, the amount of air that bypasses the throttle valve 20 is adjusted to control the engine speed during idling. The injection timing and the 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 intake air is provided upstream of the air flow meter 16, and a signal representing the intake air temperature is sent to the engine control computer 32.
Output to.

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

The engine control computer 32, the transmission control computer 34, and the throttle control computer 35 are all CPU, RAM, R.
The transmission control computer 34 includes an OM, an input / output interface circuit, an A / D converter, and the like, and performs signal processing according to a program stored in advance in the ROM while utilizing the temporary storage function of the RAM. In addition to the above signals, is a pattern signal SP indicating the selection pattern from the pattern select switch 70, a brake signal SB indicating that the brake lamp switch 72 has operated the brake, and an overdrive switch 74 to the O / D shift stage. O / indicating shift permission of
A D signal SO and an accelerator operation amount signal SAc representing an 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 engine control computer 32 and the throttle control computer 35. The pattern select switch 70 has at least an automatic engine braking pattern for automatically increasing the engine braking on a downhill road, etc., and also has a power pattern for controlling the shift of the automatic transmission 78 based on a shift map that emphasizes power performance and fuel consumption. This is for the driver to select a desired driving pattern from a plurality of predetermined driving patterns such as an economy pattern in which the shift control is performed according to the emphasized shift map.

The automatic transmission 78 includes a torque converter 110, a first transmission 112, and a second transmission 114, as shown in FIG. 3, for example. The pump impeller of the torque converter 110 is connected to the crankshaft 118 of the engine 10, and the turbine impeller of the torque converter 110 is the input shaft 1.
It is connected to the carrier 122 of the first transmission 112 via 20. The first transmission 112 includes a sun gear 124, a ring gear 126, and a planetary gear device including a planetary gear 128 rotatably disposed on the carrier 122 and meshed with the sun gear 124 and the ring gear 126. 124 and carrier 1
22 and a clutch C ₀ and a one-way clutch F _0.
Are provided in parallel, and the sun gear 124 and the housing 130
A brake B ₀ is provided between and.

The second transmission 114 is rotatably disposed on the sun gear 132, the pair of ring gears 134 and 136, and the carrier 138 so as to be rotatable on the sun gear 132, the planetary gear 140 meshed with the ring gear 134, and the carrier 142. The planetary gear 1 that is arranged and meshes with the sun gear 132 and the ring gear 136.
And a ring gear 126 of the first transmission 112. A clutch C ₁ is provided between the ring gear 136 and the ring gear 126 of the first transmission 112, and between the sun gear 132 and the ring gear 126. Clutch C
₂ is provided, and a brake B ₁ and a one-way clutch F ₁ and a brake B ₂ that are arranged in series are provided in parallel between the sun gear 132 and the housing 130, and between the carrier 138 and the housing 130. A brake B ₃ and a one-way clutch F ₂ are provided in parallel with each other. Further, the ring gear 134 and the carrier 142 are the output shaft 1
46, and its output shaft 146 is connected to the drive wheels via a differential gear device or the like.

The clutches C _{0 to} 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 engagement-controlled by a hydraulic actuator such as a multi-plate clutch or band brake, and hydraulic oil is supplied from the hydraulic control circuit 150 to the hydraulic actuator. Is becoming The hydraulic control circuit 150 is provided with a large number of switching valves and the like, and by switching the excitation and non-excitation of the solenoids S1, S2, and S3 in accordance with a signal from the transmission control computer 34, the hydraulic circuit is switched. The clutch C and the brake B are selectively engagement-controlled, and as shown in FIG. 4, any one of the four forward gears is established. In FIG. 4, the mark “◯” in the column of solenoid means excitation, and the mark “◯” in the column of clutch and brake means engagement. Shift position "D", "S",
“L” is the operating range of the driver's shift lever,
In the "D" range, the shift control is performed in the four stages from 1st to O / D, in the "S" range, the shift control is performed in the three stages from 1st to 3rd, and in the "L" range, 1st and 2nd. The shift control is performed in each stage. The gear ratio (the rotation speed of the input shaft 120 / the rotation speed of the output shaft 146) is 1 s.
It is the largest at t and becomes smaller as it becomes 2nd, 3rd, and O / D, and the gear ratio of 3rd is 1.0. Also,
In the "D" range, the engine brake acts at 3rd and O / D, and at the 1st and 2nd, the engine brake does not work due to the action of the one-way clutches F ₂ and F ₁ , but is shown in parentheses (1st). , (2nd), the brakes B ₃ and B ₁ are engaged by exciting the solenoid S3, and the engine brake operates. The engine brake is adapted to act on the 2nd of the "S" range and the 1st and 2nd of the "L" range. Although illustration is omitted, when the shift lever is operated to the “R” range, the manual shift valve of the hydraulic control circuit 150 is switched to establish the reverse shift stage.

The automatic transmission 78 is provided with a pair of rotation speed sensors 80 and 82. The rotation speed sensor 80 is the input shaft 120, that is, the torque converter 11.
The rotation speed sensor 82 detects the rotation speed N _T of the turbine impeller of 0, and the rotation speed sensor 82 detects the rotation speed N _O of the output shaft 146. The rotation speed signals representing the rotation speeds N _T and N _O , respectively. SN _T, and outputs the SN _O to the transmission control computer 34. Further, a neutral start switch 84 is provided in the hydraulic control circuit 150, and the "D", "S", from the position of the manual shift valve which is switched by operating the shift lever.
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 control computers 32, 3 are
Necessary information is transmitted and received between Nos. 4 and 35, and the throttle valve opening signal Sθ, the engine speed signal SNE, and the accelerator operation amount signal SAc are at least one of the control computers 32, 34, Alternatively, it may be supplied to 35. In addition, various other signals that represent the operating state of the automobile, such as the steering angle of the steering wheel, the gradient of the road surface, and the exhaust temperature, can be captured and used for engine control, shift control of the automatic transmission 78, and throttle control. It is possible.

Then, the engine control computer 32 uses the intake air amount, the throttle valve opening θ, the engine rotation 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. Quantity Ac
In accordance with the above, for example, the fuel injection valve 3 is based on a predetermined data map or an arithmetic expression so as to reduce fuel consumption and harmful exhaust gas while securing a required engine output.
It controls the injection amount and injection timing of the fuel gas 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, 42 by the variable valve timing mechanism. The transmission control computer 34 shifts to the throttle valve opening θ, the engine speed NE, the selected traveling 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 stage represented by the O / D signal SO. Of the automatic transmission 78 by switching between energized and deenergized states of the solenoids S1, S2, and S3 based on the propriety of gear shifting, the accelerator operation amount Ac, the output shaft rotation speed N _O of the automatic transmission 78, and the like. Switch control. The transmission control computer 34 also switches the lockup clutch of the torque converter 110 between full engagement, a slip state, and an open state by duty-controlling a solenoid (not shown) provided in the hydraulic control circuit 150. In addition, the throttle valve opening θ of the throttle valve 20 is controlled according to the accelerator operation amount Ac, and the throttle valve opening θ is adjusted to control the engine braking force when the accelerator operation amount Ac is zero. Therefore, the throttle command signal SQ is output to the throttle control computer 35. Throttle control computer 35
Is basically a throttle control signal D for controlling the throttle valve opening θ according to the throttle command signal SQ.
It is designed to output TH.

Of the shift control by the transmission control computer 34, the shift control on the upshift side will be specifically described below with reference to the flowcharts of FIGS. 5 and 6. It should be noted that the following control is performed when the "D (drive)" range in which shifting is performed in four forward gears is selected, and is repeatedly executed with a cycle time of approximately 8 to 32 msec.

The flow chart of FIG. 5 is a portion for determining whether or not the shift speed is to be changed. In step S1, it is determined whether or not the shift up to the O / D shift speed is possible based on the O / D signal SO. If it is determined that the O / D signal SO is OFF, that is, the O / D gear stage is prohibited, step S
In step 2, it is determined whether or not the current O / D gear is currently set. The current gear stage is determined by the output state of the excitation signal for exciting the solenoids S1, S2, S3. In the case of the current O / D gear stage, the flag F2 is set to "1" in step S14, and then step S15. In step 3, "3rd" is set as the next gear. The judgment in step S1 is N
If the O, that is, the O / D gear is permitted, or if the judgment in step S1 is YES, the judgment in step S2 is NO instead of the current O / D gear, and the judgment in step S3 is not currently 3rd. If NO, then step S4 is executed. In step S4, it is determined whether or not the current shift speed is the O / D shift speed. If it is not the O / D shift speed, steps S5 and thereafter are executed to determine whether or not an upshift is performed. ..

In step S5, a predetermined upshift map is searched to obtain the upshift vehicle speed Vu. As shown by the solid line in FIG. 7, the upshift map is predetermined for each type of shift based on the accelerator operation amount Ac and the vehicle speed V. The smaller the accelerator operation amount Ac is, the larger the vehicle speed V is. It is designed to be upshifted to the high speed side. Shift up vehicle speed Vu
It is determined according to the upshift map based on the accelerator operation amount Ac, at the next step S6, the current vehicle speed V and the shift-up vehicle speed Vu that corresponds to the output shaft rotational speed N _O of the rotational speed signal SN _O represents Compare
Determine whether to upshift. That is, V ≦
If it is Vu, it is not necessary to perform an upshift, and it is determined in step S8 whether or not the current gear is 1st. If it is 1st, the flag F1 is set to "0" in step S9, and a series of gear shift determination is completed. However, if V> Vu, the flag F1 is set to "1" in step S7, and then, in step S15, the shift speed higher than the current shift speed is set as the next shift speed. In this case, even if the current gear stage is, for example, 2nd, the accelerator operation amount Ac sharply decreases after the gear shift determination to 3rd is made and before the gear stage is actually switched to 3rd. When the "3 → O / D" upshift line is exceeded, the O / D gear is set. In step S5, the shift-up vehicle speed Vu for all upshift lines is obtained from the current accelerator operation amount Ac, and in step S6, the respective shift-up vehicle speed Vu and the current vehicle speed V are compared to determine the upshift shift. Do it.

On the other hand, if the determination in step S3 is YES, the determination in step S4 is YES, or the determination in step S8 is NO, step S10 and the following steps are executed to determine whether to downshift. To judge. In step S10, a predetermined downshift map is searched for the downshift vehicle speed Vd. The downshift map is as shown by the dashed line in FIG.
It is predetermined for each type of shift based on the accelerator operation amount Ac and the vehicle speed V. As the accelerator operation amount Ac increases and the vehicle speed V decreases, the gear shifts to the lower speed side. The downshift vehicle speed Vd is obtained according to the downshift map based on the accelerator operation amount Ac, and in the next step S11, the output shaft rotation speed N _O.
Is compared with the current vehicle speed V corresponding to the shift-down vehicle speed Vd to determine whether or not a downshift is to be performed. That is, if V> Vd, it is not necessary to perform a downshift, the flag F2 is set to "0" in step S13, and a series of shift determination is ended, but if V≤Vd, the flag F2 is set to "0" in step S12. After setting "1", in step S15, a shift speed lower than the current shift speed is set as the next shift speed. In this case, even if the current gear stage is, for example, O / D, the accelerator operation amount Ac increases sharply after the gear shift determination to 3rd is made and before the gear stage is actually switched to 3rd. If the “2 ← 3” downshift line is exceeded, the 2nd shift speed is set. In step S10, the shift-down vehicle speed Vd for all downshift lines is obtained from the current accelerator operation amount Ac, and in step S11, the respective shift-down vehicle speed Vd and the current vehicle speed V are compared to determine the downshift. Do it.

When the next shift speed is set in step S15, the shift timing time T ₁ is set in step S16. This gear shift timing time T ₁ is a delay time after the gear shift judgment is made until the gear is actually switched, and when the accelerator pedal is quickly released to apply the engine brake on the downhill,
Accelerator operation amount A after the upshift is judged
It is set to include the margin time in the time until c becomes substantially zero. Specifically, the time required for the accelerator operation amount Ac to be returned from 100% to 0% according to the urging force of the spring, in other words, a constant value of about 100 to 200 msec is taken into consideration in consideration of the return speed of the accelerator pedal. It may be set, or the accelerator operation amount Ac and the vehicle speed V at the time of the shift determination,
You may make it set by a map, a calculation formula, etc. according to a gear stage etc. The shift timing time T ₁ is
Since it is for determining whether or not the accelerator operation amount Ac becomes zero by delaying the execution of the upshift in this way, it is not necessarily required in the case of the downshift and is set only in the case of the upshift. In the case of downshifting, the shift timing time T ₁ is different from that of the shift timing T _{1 in} order to avoid performing multiple downshifts (multiple shifts) in a short time when the accelerator pedal is depressed. The delay time may be set.

The flowchart of FIG. 6 is a portion for executing an upshift in accordance with the shift determination of FIG.
At 0, it is determined whether or not the flag F1 is "1", that is, whether or not the upshift is determined. Flag F
If 1 is "1", the steps following step S21 are executed, but if not, step S3 is immediately executed.
2 is executed, the timer T is reset, and the process ends. In step S21, it is determined whether or not the shift range represented by the shift range signal SR is "D (drive)", and in step S22, it is determined whether or not the traveling pattern represented by the pattern signal SP is "automatic engine braking pattern". determine, it is determined whether larger than the lower limit vehicle speed V1 of the vehicle speed V is preset to correspond to the output shaft rotation speed N _O representing the rotational speed signal SN _O in step S23, step S24 in the vehicle speed V is in advance It is determined whether or not the vehicle speed is equal to or lower than the predetermined upper limit vehicle speed V2. In step S25, the accelerator is turned off, that is, the accelerator operation amount Ac represented by the accelerator operation amount signal SAc.
Is substantially zero, specifically 5% considering the detection error etc.
It is determined whether or not the degree is equal to or less than a certain degree, and in step S26, it is determined whether or not the next shift stage set in step S15 is an O / D shift stage. In the D range, as shown in FIG. 4, 1st and 2nd where engine braking does not work,
Engine brake 3rd and O / D total 4
This is a case where the shift control is performed in one shift stage. Further, the lower limit vehicle speed V1 and the upper limit vehicle speed V2 define a vehicle speed range in which special control for engine braking is performed, and the lower limit vehicle speed V1 is the minimum vehicle speed at which an upshift to the O / D gear is performed 35 km. The vehicle speed is set to about / h, and the upper limit vehicle speed V2 is set to, for example, about 110 km / h.
Then, even one of steps S21 to S26 is N
In the case of O, in step S28, there is no change in the next shift stage set in step S15, but if the determinations in steps S21 to S26 are all YES,
In step S27, the next gear is changed to "3rd". The step S26 is to determine whether the next gear set in step S15 is O / D. Even in the cycle after the next gear is changed from O / D to 3rd in step S27, The determination in step S26 is YES.

In step S29, it is determined whether or not the content measured by the timer T is the shift timing time T ₁ or more.
The above step S2 is executed until the shift timing time T ₁ is reached.
Although 0 or less is repeated, when the shift timing time T ₁ is reached, step S30 is executed and the solenoids S1, S
By switching between excitation and non-excitation in 2 and S3, the gear stage of the automatic transmission 78 is switched to the next gear stage set in step S15 or the 3rd gear stage changed in step S27. Then, in step S31, the flag F1
Is set to "0", the timer T is reset in step S32, and the series of upshifts is completed.

Here, in this embodiment, the step S6 is performed.
Even if an upshift to the O / D shift stage is made in step S30, the shift stage is actually changed in step S30, that is, the shift timing T ₁ elapses after the shift determination is made. And the accelerator OF
When all the conditions of steps S21 to S26 including F are satisfied, the next gear is changed to 3rd, and therefore, when the driver releases the accelerator because he / she does not want to accelerate any more on a downhill or the like. Even if an upshift shift determination is made with a decrease in the accelerator operation amount Ac, the actual shift to the O / D shift stage is prevented, and the engine braking force decreases with the shift to the O / D shift stage. Is well avoided. For example, when the driver releases the accelerator in the case of traveling for the 2nd time at the point A in FIG. 7, the "2 → 3" upshift line and the "3 → O / D"
Since the accelerator operation amount Ac becomes zero across the upshift line, a final shift determination from 2nd to O / D is made in step S6, and the O / D shift stage is set as the next shift stage in step S15. It is set, but "2 → 3"
Shift timing time T after the upshift is determined
_{If the} accelerator operation amount Ac becomes zero before ₁ has passed,
Crossing the "3 → O / D" upshift line, the next gear is O
/ D, the next gear is 3 in step S27.
Since it is changed to rd, it is not upshifted to the O / D gear.

Even if the accelerator is turned off once,
If the pedal is depressed again before reaching the shift timing time T ₁ , the determination in step S25 is NO, and in step S28 the next shift stage is set to the O / D set in step S15. When the accelerator is stepped on, the driver does not need so much engine braking force, so there is no problem in upshifting to the O / D gear. The determination of step S29 may be inserted between steps S20 and S21, and when the shift timing time T ₁ has elapsed, step S21 and subsequent steps may be executed to switch the shift speed.

Also, the accelerator return speed is relatively slow,
Even if the accelerator is not turned off within the gear change timing time T ₁ , the gear change as set in step S15 is executed, but in this case as well, it is considered that the driver does not need much engine braking force, so O There is no problem in upshifting to the / D gear. In other words,
When the driver needs the engine braking force, he / she should release the accelerator pedal promptly, and when he / she wants to coast or the like that does not require the engine braking force so much, he / she should release the accelerator pedal slowly. It's good.

On the other hand, even when the accelerator pedal is released on a downhill, the vehicle speed V may increase and an upshift determination may be made. Even in that case, step S27 is executed to increase the speed to the 3rd gear stage. Since the shift is stopped, the reduction of the engine braking force due to the shift to the O / D gear is favorably avoided.

As described above, according to the gear shift control apparatus of the present embodiment, when the accelerator operation amount Ac becomes substantially zero within the gear shift timing time T ₁ after the upshift gear shift determination is made, the operation is performed. Upshifts to the O / D gear are blocked because the person needs engine braking force,
Therefore, the decrease in the engine braking force due to the upshift to the O / D gear is favorably avoided.

In the present embodiment, of the series of signal processing by the transmission control computer 34, the part that executes steps S5 and S6 of FIG. 5 corresponds to the shift determining means, and the part that executes step S27 of FIG. 6 is up. This corresponds to the shift prohibiting means, the portion that executes step S29 corresponds to the delay means, and the portion that executes step S30 corresponds to the switching means. In addition, the shift timing time T ₁
Corresponds to a delay time, and the map in FIG. 7 corresponds to a predetermined shift condition.

Incidentally, in the above embodiment, the accelerator is once OF
Even if F is reached, if the pedal is depressed again before reaching the shift timing time T ₁ , the determination in step S25 is NO, and in step S28 the next shift stage is set to O / D set in step S15. However, as shown in FIG. 8, when the accelerator is once turned off and the next shift speed is changed to 3rd in step S27, immediately after the shift timing time T ₁ , the step S
It is also possible to execute 30 so that the shift speed can be switched to 3rd.

Although one embodiment of the present invention has been described in detail with reference to the drawings, the present invention can be implemented in other modes.

For example, in the above-described embodiment, the vehicle in which the throttle valve opening θ is controlled by the throttle control computer 35 has been described, but the present invention is also applicable to a vehicle in which the throttle valve 20 is mechanically connected to the accelerator pedal to open and close. The invention is applicable, in which case the accelerator operation amount A
The shift condition (shift map or the like) may be set using the throttle valve opening θ instead of c.

Further, in the above embodiment, when the automatic engine braking pattern is selected by the pattern select switch 70, the upshift prohibition control for prohibiting the upshift to the O / D shift stage is performed. The upshift inhibition control may be performed when another traveling pattern such as a pattern is selected, or the upshift inhibition control may be executed regardless of the type of the traveling pattern. It is of course possible to dispose the engine brake control switch separately from the pattern select switch 70.

Further, in the above-described embodiment, step S23 is set as a condition for performing the inhibition control of the upshift to the O / D gear stage.
Although the vehicle speed limitation of S24 and S24 is provided, the vehicle speed limitation is not always necessary, and the range of the vehicle speed limitation is appropriately determined. Another condition may be added as a condition for performing the upshift prohibition control.

Further, in the above embodiment, the maximum speed of O /
Only the upshift to the D shift stage was prohibited, but if the engine brake is applied even at the 1st shift stage or the 2nd shift stage, the "2 → 3" shift or the "1 → 2" shift is performed.
Shifting can also be prohibited. 5
The present invention can be similarly applied to an automatic transmission that shifts gears in multiple gears.

Further, although the engine control computer 32, the transmission control computer 34, and the throttle control computer 35 are separately configured in the above embodiment, they may be configured by a single computer. It is possible.

Although not exemplified one by one, the present invention can be carried out in various modified and improved modes based on the knowledge of those skilled in the art.

[Brief description of drawings]

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

FIG. 2 is a diagram illustrating a configuration of an automatic transmission, an engine, and the like including a shift control device that is an embodiment of the present invention.

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

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

5 is a flow chart for explaining a gear shift determination operation in the gear shift control device of FIG.

FIG. 6 is a flowchart illustrating an operation of upshift inhibition control in the shift control device of FIG.

FIG. 7 is an example of a shift map for switching the shift speed of the automatic transmission of FIG.

FIG. 8 is a flowchart illustrating another aspect of the upshift prohibition control, corresponding to FIG. 6.

[Explanation of symbols]

34: Transmission control computer 76: Accelerator operation amount sensor 78: Automatic transmission T ₁ : Shift timing time (delay time) Steps S5, S6: Shift determination means Step S27: Upshift prohibiting means S29: Delay means Step S30: Switching means

Claims (1)

[Claims] 1. An automatic transmission having a plurality of shift speeds, and a shift of the automatic transmission based on a predetermined shift condition such that the shift speed is upshifted to a higher speed side as the accelerator operation amount is smaller. A shift control device for an automatic transmission, comprising: a shift determination means for determining whether or not to upshift a gear; and a switching means for upshifting a shift speed of the automatic transmission according to a determination result of the shift determination means, Delay means for delaying switching of the shift speed by the switching means from the judgment of the shift judging means by a predetermined delay time, and the accelerator operation amount before the shift speed is switched by the switching means. When it becomes less than a predetermined value of zero, at least an upshift prohibition means for prohibiting upshift to the highest speed stage is provided. Shift control system for an automatic transmission.