JP4622234B2 - Automatic transmission control device - Google Patents

Description

  The present invention relates to an automatic shift control device that automatically shifts a transmission to a gear stage that can travel with the lowest fuel consumption within a range in which the vehicle does not stall.

  In an automatic shift control device that automatically shifts a transmission, a shift control called a low fuel consumption mode that shifts the gear stage of the transmission to a gear stage that can travel with the lowest fuel consumption within a range in which the vehicle does not stall is performed. What is executed has been proposed (see, for example, Patent Document 1).

  The outline of this shift control will be described with reference to FIG.

  In the figure, the horizontal axis represents the engine rotation speed, and the vertical axis represents the net average effective pressure Pme (corresponding to engine torque). The diagram indicated by the solid line A in the figure is an isofuel consumption diagram of the engine, and means that the fuel consumption rate SFC is the same if it is on the same line. In this iso-fuel consumption diagram A, the closer to the inner line, the better the fuel efficiency, and conversely, the closer to the outer line, the worse the fuel efficiency. A line indicated by a dotted line B is a maximum torque diagram of the engine.

  In the low fuel consumption mode, the minimum horsepower required for maintaining the current driving state (that is, the output required for steady running in the current state) is determined based on the driving state of the vehicle, and the equal horsepower line Create Figure C. The horsepower required for steady running varies according to running conditions (road surface gradient, etc.) and accelerator opening, that is, engine load.

  Now, assume that the transmission is running at N gears and the engine speed is R (N). Then, first, the minimum necessary torque T (N) for maintaining the current operating state at the current gear stage N is calculated, and based on the torque T (N) and the engine speed R (N), etc. A horsepower diagram C is created. In FIG. 6, the symbols in parentheses for the engine speed R and the engine torque T indicate the corresponding gear stages.

  Next, based on the current engine speed R (N) and the gear ratio of each gear stage of the transmission, the virtual engine speed after the shift is determined for each gear stage of the transmission, and the virtual engine rotation is determined. Based on the speed and the constant horsepower diagram C, the torque required to maintain the current operating state after the gear shift is determined for each gear stage. That is, in FIG. 6, the virtual engine rotation speed after the transmission is shifted up one stage from the current gear stage N is R (N + 1), and the torque required to maintain the current operating state at the N + 1 stage is T (N + 1). Further, the virtual engine rotation speed after the transmission is shifted up from the current gear stage N by two stages is R (N + 2), and the torque required to maintain the current driving state at N + 2 stage is T (N + 2). is there. Although only the current gear stages N to N + 2 are shown in the figure, the post-shift virtual engine rotation speed R and the required torque T are determined at all the gear stages of the transmission.

  Next, only a gear stage whose required torque T after the shift is equal to or less than the maximum torque diagram B of the engine is determined as a selectable gear stage. This is because if the required torque T after the shift is larger than the maximum torque of the engine, the vehicle will stall after the shift. Then, the gear stage that can travel with the lowest fuel consumption is selected as the target gear stage among the selectable gear stages, and the transmission is shifted to the target gear stage.

  In the example of FIG. 6, the current gear stage N and a gear stage N + 1 that is one higher than the current gear are determined as selectable gear stages, and the fuel efficiency of both is compared. Here, since the fuel consumption is better in the N + 1 stage than in the current gear stage N, the transmission is shifted up to the N + 1 stage.

Japanese Utility Model Publication No. 60-67243

  By the way, in the automatic transmission control device that selects the target gear stage based on the engine rotational speed or the like in this way, the target gear stage can be selected while the clutch is disengaged in order to change the speed of the transmission. Can not. This is because, when the clutch is disengaged, the engine and the wheel are disengaged, so that the engine rotation speed does not correspond to the traveling state (vehicle speed or the like) of the vehicle.

  Therefore, the present applicant has devised prohibiting the selection of a new target gear stage while the clutch is disengaged (during shifting of the transmission).

  However, it has been found that if the selection of a new target gear stage is prohibited while the clutch is disengaged, the following problems may occur.

  This will be described with reference to FIG.

  Now, assume that the gear stage of the transmission is traveling at N stages, and a shift instruction from the current gear stage N to N + 1 stage is issued based on the equihorse power diagram C.

  Then, although the clutch is disengaged and the transmission is changed, the vehicle speed may decrease during this time, such as when the climbing slope of the road surface increases or the driver steps on the brake. Then, after the transmission is actually shifted to the N + 1 stage (the clutch is connected) than the virtual engine rotation speed R (N + 1) at the N + 1 stage at the time when the shift instruction is issued (before the clutch is disengaged). After that, the engine speed R ′ (N + 1) becomes low.

  As a result, as shown in the figure, the maximum torque ETmax (N + 1) of the engine after the shift may be lower than the minimum torque T (N + 1) necessary to maintain the current operating state, If so, the vehicle will stall.

  SUMMARY OF THE INVENTION Accordingly, an object of the present invention is to solve the above-described problems and to provide an automatic transmission control device that can select an appropriate target gear stage even during transmission shifting.

In order to achieve the above object, the present invention provides a shift control means for selecting a target gear stage based on at least the engine rotational speed and automatically shifting the transmission to the target gear stage, and a clutch according to the shift of the transmission. Clutch control means for controlling connection / disconnection of the engine and engine output based on the accelerator pedal opening except when the transmission is shifting, and at the time of shifting, the accelerator is operated before the clutch is disconnected by the clutch control means. Shifting to engine output control based on control accelerator opening unrelated to pedal opening, the control accelerator opening is raised so as to approach the accelerator pedal opening after the shifting operation of the transmission is completed. The engine output control based on the accelerator pedal opening when the control accelerator opening coincides with the accelerator pedal opening after the clutch is engaged Engine control means, and the shift control means includes the control accelerator opening and the accelerator pedal opening within a period in which the engine control means executes engine output control based on the control accelerator opening. when more than a predetermined value the difference between, to calculate the virtual engine rotational speed after the shift in the current target gear position based on the output shaft rotational speed of the transmission, after transmission to the current target gear position A minimum torque required for preventing the vehicle from stalling and a maximum engine torque at the virtual engine speed are determined. When the maximum torque falls below the required torque, the current target is set as a new target gear stage. A gear stage lower than the gear stage is selected.

The shift control means prohibits the selection of the new target gear stage when the maximum torque is equal to or greater than the necessary torque , and on the other hand, when the maximum torque falls below the necessary torque, The prohibition of selection of the target gear stage may be canceled, and a gear stage lower than the current target gear stage may be selected as a new target gear stage .

In order to achieve the above object, the present invention provides a shift control means for selecting a target gear stage based on at least the engine rotational speed and automatically shifting the transmission to the target gear stage, and a clutch according to the shift of the transmission. Clutch control means for controlling connection / disconnection of the engine and engine output based on the accelerator pedal opening except when the transmission is shifting, and at the time of shifting, the accelerator is operated before the clutch is disconnected by the clutch control means. Shifting to engine output control based on control accelerator opening unrelated to pedal opening, the control accelerator opening is raised so as to approach the accelerator pedal opening after the shifting operation of the transmission is completed. The engine output control is based on the accelerator pedal opening so that the control accelerator opening coincides with the accelerator pedal opening after the clutch is engaged. An engine control unit that returns, the shift control means, within the time above SL engine control means is executing the engine output control based on the control accelerator opening, the control accelerator opening and the accelerator pedal opening when the difference between the degrees is a predetermined value or more, based on the output shaft rotational speed of the transmission and calculates a virtual engine rotational speed after the shift in the current target gear position, the virtual engine speed is a predetermined lower limit value In the following cases, a gear stage lower than the current target gear stage is selected as a new target gear stage.

Further, the shift control unit, when the upper Symbol virtual engine rotational speed is less than the lower limit, based on the output shaft rotational speed of the transmission, the virtual engine after the shift for each gear stage of the transmission The rotational speed may be determined, and the lowest gear stage among the gear stages whose virtual engine rotational speed does not exceed a predetermined upper limit value may be selected as the new gear stage.

  Further, the shift control means may automatically shift the transmission to a gear stage that can travel with the lowest fuel consumption within a range in which the vehicle does not stall.

  According to the present invention, an excellent effect that an appropriate target gear stage can be selected even during a shift of the transmission is exhibited.

Example 1
Hereinafter, a preferred embodiment of the present invention will be described in detail with reference to the accompanying drawings.

  FIG. 1 is a schematic diagram of an automatic transmission control device for a vehicle according to the present embodiment.

  The automatic transmission control device of this embodiment performs automatic transmission control of a multi-stage transmission 3 (here, a forward 12-stage transmission) connected to a diesel engine 1 via a clutch 2.

  The engine 1 is controlled by an engine control means (ECU) 6. The ECU 6 basically determines the actual engine rotation speed and accelerator opening (engine opening) from the outputs of the engine rotation sensor 7 that detects the rotation speed of the engine 1 and the accelerator opening sensor 8 that detects the opening of the accelerator pedal 5. Load) is read, and the fuel injection amount and fuel injection timing (engine output) are controlled mainly based on these. As will be described in detail later, the ECU 6 determines fuel during the shift of the transmission 3 based on the control accelerator opening processed by the ECU 6 independently of the actual accelerator pedal opening detected by the accelerator opening sensor 8. Control injection quantity and timing.

  The clutch 2 and the transmission 3 are automatically controlled by the TMCU 9. That is, the TMCU 9 of the present embodiment has functions as a shift control means and a clutch control means in “Claims”. The ECU 6 and the TMCU 9 are connected to each other via a bus cable or the like and can communicate with each other.

  The clutch 2 is provided with a clutch actuator 10, and the TMCU 9 outputs a signal to the clutch actuator 10 to control connection / disconnection of the clutch 2 via the clutch actuator 10. In this embodiment, the clutch 2 can be manually connected / disconnected by the clutch pedal 11. The clutch 2 is provided with a clutch stroke sensor 14 for detecting the position of a clutch plate (not shown) (hereinafter referred to as clutch position), and the detected value of the clutch stroke sensor 14 is transmitted to the ECU 6 and the TMCU 9.

  Further, the transmission 3 is provided with a gear shift unit (GSU) 12, and the TMCU 9 outputs a signal to the GSU 12 and controls the transmission 3 through the GSU 12. The transmission 3 is provided with a gear position sensor 23 for detecting the gear position, and the detection value of the gear position sensor 23 is transmitted to the TMCU 9. Further, the transmission 3 is provided with an output shaft sensor 28 for detecting the rotational speed of its output shaft (not shown), and the detection value of the output shaft sensor 28 is transmitted to the TMCU 9.

  The TMCU 9 executes a shift control referred to as a low fuel consumption mode as described in the “Background Art” section. Although not described in detail above, basically, the virtual engine rotation speed and the necessary torque after the shift are changed for each gear stage of the transmission 3 based on the actual engine rotation speed detected by the engine rotation sensor 7 or the like. And the gear stage that can travel with the lowest fuel consumption within the range where the vehicle does not stall (the range where the required torque does not exceed the maximum torque of the engine) is selected as the target gear stage, and the transmission 3 is moved to the target gear stage. It automatically shifts.

  When shifting the transmission 3, the TMCU 9 first outputs a signal to the clutch actuator 10 to disengage the clutch 2, and then outputs a signal to the GSU 12 to execute a shifting operation (gear release, gear in) of the transmission 3. When the shifting operation is completed, the clutch 2 is connected. In the present embodiment, the transmission 3 can also be manually shifted by the shift change means 29.

  The ECU 6 executes engine output reduction control in order to reduce shock caused by clutch engagement / disengagement when the transmission operation of the transmission 3 is performed by the TMCU 9.

  This will be described with reference to FIG.

  In the figure, the horizontal axis is time, and the vertical axis is the clutch position, and the lower stage is the accelerator opening that the ECU 6 uses to determine the fuel injection amount and timing. 2 shows an example in which the opening degree of the accelerator pedal 5 does not change before and after the transmission 3 is shifted.

  First, before the time t1, the ECU 6 controls the fuel injection amount and timing (engine output) based on the actual opening degree of the accelerator pedal 5 detected by the accelerator opening degree sensor 8.

  Then, it is assumed that a shift instruction signal is output from TMCU 9 at time t1. Then, from this time t1, the ECU 6 controls the engine output based on the control accelerator opening that is unrelated to the actual accelerator pedal opening. The control accelerator opening is for reducing the engine output to a very small value (for example, the output during idling) in order to reduce the shock caused by the clutch engagement / disengagement. That is, the control accelerator opening is the same as the accelerator pedal opening at time t1, but then gradually decreases, and is maintained in that state if it decreases to the set value A1.

  At time t <b> 2 when the control accelerator opening is reduced to a predetermined value A <b> 2, the TMCU 9 disengages the clutch 2 and starts a shift operation of the transmission 3. If the speed change operation of the transmission is completed at time t3, the TMCU 9 controls the clutch 2 to the contact side.

  At time t4, if the clutch 2 is operated to the contact side to a predetermined position K (for example, a position where torque starts to be transmitted from the input side to the output side of the clutch 2), the ECU 6 sets the control accelerator opening to the actual accelerator position. Raise the pedal to approach the pedal opening. If the control accelerator opening coincides with the accelerator pedal opening at time t6, the engine output control based on the control accelerator opening is terminated, and the engine output control based on the accelerator pedal opening is returned.

  By the way, during the shift control of the transmission 3, the target gear stage cannot be selected based on the engine speed. This is because the engine rotation speed does not correspond to the actual accelerator pedal opening because the ECU 6 executes engine output control based on the control accelerator opening. Further, while the clutch 2 is disengaged, the engine rotational speed does not correspond to the traveling state of the vehicle (vehicle speed or the like), which is also the reason that the target gear stage cannot be selected based on the engine rotational speed. The term “during gear shift control” of the transmission 3 here refers to a period (time t1 to t6 in FIG. 2) in which the ECU 6 performs engine output control based on the control accelerator opening that is unrelated to the accelerator pedal opening. The period includes all periods in which the clutch 2 is disengaged.

  Therefore, the automatic transmission control device of the present embodiment is devised in order to enable selection of an appropriate target gear stage even during the transmission control of the transmission 3. Specifically, during the shift control of the transmission 3, the virtual engine rotation speed is calculated based on the output shaft rotation speed (corresponding to the vehicle speed) of the transmission 3, and the target gear stage is set based on the virtual engine rotation speed. Select. In this way, it is possible to select a target gear stage that matches the driving state (vehicle speed, etc.) of the vehicle.

  A specific control method will be described with reference to the flowchart of FIG. This flowchart is executed by the TMCU 9 every predetermined period.

  First, the outline of this control content will be described. First, when control for shifting the transmission 3 to a predetermined target gear stage is being executed (during gear shift control), the control accelerator opening and the accelerator in the ECU 6 are controlled. While the difference between the pedal opening and the pedal opening is larger than a predetermined value, selection of a new target gear is basically prohibited. However, during that time, based on the output shaft rotation speed and the gear ratio, the virtual engine rotation speed after shifting at the predetermined target gear stage and the engine maximum torque at the virtual engine rotation speed are always calculated. Then, the engine maximum torque is compared with the torque required to maintain the current operating state, and when the engine maximum torque falls below the required torque, the prohibition of selection of the new target gear stage is canceled, and a new A gear stage that is one stage lower than the predetermined target gear stage is selected as the target gear stage.

  Steps S1 to S4 are steps for determining whether or not to prohibit selection of a new target gear stage.

  In step S1, it is determined whether or not the target gear stage selected by the TMCU 9 is different from the current gear stage detected by the gear position sensor 23. That is, in this step S1, it is determined whether or not a shift instruction is output. If the determination in step S1 is YES, the state of the transmission 3 and the clutch 2 is in the range of time t1 to t3 in FIG. 2, that is, the gear shift operation (gear removal, gear in) is performed after the gear shift instruction is output. It means that it is until completion.

  In step S2, it is determined whether or not the clutch position detected by the clutch stroke sensor 14 is on the disengagement side with respect to a predetermined first set value. In the present embodiment, the first set value is set to be the same as the clutch position K at time t4 when the control accelerator opening starts to approach the accelerator pedal opening in FIG. The determination of YES in step S2 means that the state of the clutch 2 is operated on the contact side from the time t2 to t4 in FIG. 2, that is, until the first set value (K) after the clutch is disengaged. Means that it is between. Step S2 is for determining whether or not the clutch 2 is in a state where an appropriate selection of the target gear stage can be performed based on the engine speed.

  In step S3, the absolute value ΔA of the difference between the control accelerator opening in the ECU 6 and the actual accelerator pedal opening is calculated. When the engine output is controlled other than during shifting, that is, when the engine output is controlled based on the actual accelerator pedal opening, the difference ΔA is set to zero.

  In step S4, it is determined whether or not the difference ΔA between the control accelerator opening and the accelerator pedal opening calculated in step S3 is equal to or greater than a predetermined second set value. In this embodiment, the second set value is 5%. The determination of YES in step S4 means that the state of the ECU 6 is in the range from time t1 ′ to t5 in FIG. 2, that is, the control accelerator opening is reduced and the difference from the accelerator pedal opening is 5%. It means that the time from the time t1 ′, which has been described above, to the time t5 when the control accelerator opening increases and the difference from the accelerator pedal opening becomes 5%.

  If it is determined NO in these steps S1, S2, and S4, it is determined that it is possible to select an appropriate target gear stage based on the engine speed, and the process proceeds to step S5 and a new one is set. Allows selection of the target gear.

  In step S4, when the difference ΔA between the control accelerator opening and the accelerator pedal opening is smaller than 5%, the selection of a new target gear stage based on the engine speed is permitted. If the difference between the accelerator opening and the accelerator pedal opening is small, the difference between the actual engine speed and the engine speed corresponding to the accelerator pedal opening is small. It is because it is thought that it will not be selected. Of course, the second set value may be set to zero, and selection of a new target gear stage based on the engine speed may not be permitted until the ECU 6 has completely shifted to engine output control based on the accelerator pedal opening.

  If any one of steps S1, S2 and S4 is determined to be YES, selection of a new target gear is basically prohibited (step S9).

  However, as described above, while it is determined YES in steps S1, S2, and S4, the virtual engine rotation speed after the shift is always calculated based on the output shaft rotation speed, and the current vehicle running state is calculated. Then, it is determined whether the target gear stage to be currently shifted is appropriate. If it is determined that the current target gear stage is not appropriate, the selection prohibition of the new target gear stage is canceled and a gear stage that is one step lower than the current target gear stage is selected as the new target gear stage. To do. Steps S6 to S8 and S10 are specific control contents.

  In step S6, a virtual engine rotational speed after shifting at the current target gear stage is calculated based on the output shaft rotational speed and the gear ratio, and the virtual engine rotational speed and the engine maximum torque diagram (dotted line B in FIG. 6). And the virtual engine maximum torque after the shift is determined. The vehicle speed may change even during the shift control, and the output shaft rotation speed changes as the vehicle speed changes. As a result, the engine rotational speed and the engine maximum torque after shifting at the current target gear stage change. In step S6, changes in the engine rotational speed and engine maximum torque after shifting are always read.

  Next, in step S7, after shifting to the current target gear stage, the torque required to maintain the current operating state is read. For this required torque, the value used to select the current target gear stage is used. For example, referring to FIG. 6, if the transmission 3 is currently traveling in N stages, N + 1 stages based on the engine speed R (N) and the required torque T (N) in N stages. The virtual engine rotation speed R (N + 1) and the required torque T (N + 1) are determined, and as a result, the N + 1 stage is selected as the target gear stage, and then the shift control is performed. The necessary torque in step S7 Means the required torque T (N + 1) at this time.

  Returning to FIG. 3, in step S8, it is determined whether the required torque determined in step S7 is greater than the engine maximum torque determined in step S6. If the required torque is equal to or less than the engine maximum torque, there is no fear that the vehicle will stall after the end of the shift, and therefore the process proceeds to step S9 and selection of a new target gear stage is prohibited. Accordingly, the transmission 3 is initially shifted to the target gear stage.

  On the other hand, if it is determined in step S8 that the required torque is greater than the engine maximum torque, the process proceeds to step S10, and a gear stage that is one step lower than the current target gear stage is selected as the new target gear stage. Is done. Accordingly, the transmission 3 is initially shifted to the target gear stage-1 stage. For example, when the initial target gear stage is a gear stage that is one stage higher than the traveling gear stage before the shift, the transmission 3 is maintained at the gear stage before the shift control as a result. In addition, when the initial target gear stage is a gear stage that is two stages higher than the traveling gear stage before the shift, the transmission 3 is shifted up by one stage. If the selection of a new target gear stage is prohibited at the time when this flow was executed last time, the prohibition is canceled in step S10, and a gear stage that is one step lower is selected as the new gear stage. .

  By the way, when it is determined in step S8 that the required torque is greater than the engine maximum torque, it means that the vehicle speed has decreased during the shift control and the engine maximum torque after the shift has fallen below the required torque. . In other words, when the gear shift instruction is issued, naturally, a gear stage in which the virtual engine maximum torque is larger than the required torque is selected, but if the vehicle speed decreases during gear shift control to that gear stage, The virtual engine maximum torque may decrease and fall below the required torque. When this happens, when the shifting operation is continued and the clutch 2 is connected, the engine torque becomes insufficient with respect to the driving state of the vehicle, and the vehicle stalls. In this embodiment, in such a case, the target gear stage is changed to a gear stage that is one step lower, so that a shortage of torque can be avoided.

  Thus, according to the automatic transmission control device of the first embodiment, when the transmission 3 is shifting to any gear stage, the virtual engine rotation speed is set based on the output shaft rotation speed of the transmission 3. Since the target gear stage is selected based on the calculated virtual engine rotation speed, it is possible to select an appropriate target gear stage that matches the driving state (vehicle speed) of the vehicle even while the transmission 3 is shifting. Become.

  In the above embodiment, when the virtual engine maximum torque after the shift is less than the required torque, the gear stage that is one step lower than the initial target gear stage is selected as the new target gear stage. There is no need for lower gear. For example, a gear stage that can travel with the lowest fuel consumption among the gear stages lower than the initial target gear stage may be selected as a new target gear stage.

(Example 2)
Next, a second embodiment of the present invention will be described using the flowchart of FIG.

  In this embodiment, during the shift control of the transmission 3, the virtual engine rotation speed is calculated based on the output shaft rotation speed of the transmission 3, and the virtual engine rotation speed is equal to or lower than a predetermined lower limit value. It is determined that the vehicle may be stalled after the shift, and a gear stage lower than the initial target gear stage is selected as a new target gear stage.

  In the figure, steps S101, S102, S103, S104, and S105 have the same contents as steps S1, S2, S3, S4, and S5 shown in FIG.

  As in the first embodiment, if any one of steps S101, S102, and S104 is determined to be YES, the selection of a new target gear is basically prohibited (step S108).

  However, as described above, while YES is determined in steps S101, S102, and S104, the virtual engine rotation speed after the shift is always calculated based on the output shaft rotation speed, and is the value below the lower limit value? Determine. When the virtual engine rotational speed becomes equal to or lower than the lower limit value, the prohibition of selection of a new target gear stage is canceled, and a gear stage lower than the current target gear stage is selected as a new target gear stage. Steps S106, S107, and S109 are specific control contents.

  In step S106, the virtual engine rotational speed after the shift at the current target gear stage is calculated based on the output shaft rotational speed and the gear ratio.

  In step S107, it is determined whether or not the virtual engine rotation speed calculated in step S106 is equal to or lower than a predetermined lower limit value (here, 700 rpm). This lower limit value is an engine rotation speed at which the vehicle can be regarded as stalling, and is appropriately set based on engine characteristics and the like. Accordingly, if it is determined in step S107 that the virtual engine speed is equal to or lower than the lower limit value, the process proceeds to step S109, and a new target gear stage selection routine described later is executed. If it is determined in step S107 that the virtual engine speed is greater than the lower limit value, the process proceeds to step S108, and selection of a new target gear stage is prohibited. Accordingly, the transmission 3 is shifted to the original target gear stage.

  The new target gear stage selection routine will be described with reference to FIG.

  When this control is executed for the first time, first, in step S201, the starting stage + 1 stage is determined as the N stage. The starting stage is stored in the TMCU 9, and may always be the same stage, or may change according to the state (total weight) of the vehicle. The TMCU 9 always stores the latest start gear stage. Then, the optimum gear stage is searched from this starting stage +1 stage to the highest speed gear stage. Here, the reason why the starting stage is excluded from the target gear stage is that the shift control is being performed. This is because the vehicle is traveling and it is unlikely that it is necessary to shift to the starting position.

  Next, it progresses to step S202 and it is determined whether the N stage determined by step S201 is more than the highest speed gear stage. When this control is executed for the first time, normally, N stage <highest speed gear stage.

  When it is determined NO in step S202, the process proceeds to step S203, and the post-shift virtual engine rotation speed at the N stage is calculated based on the output shaft rotation speed and the gear ratio.

  And it progresses to step S204 and it is determined whether the virtual engine rotational speed determined by step S203 is below a predetermined upper limit (here 1500 rpm). This upper limit value is a value that may lead to problems such as deterioration of fuel consumption and an upshift immediately after a shift, and is set as appropriate based on engine characteristics and the like.

  If it is determined in step S204 that the post-shift virtual engine rotation speed in the N stage is equal to or lower than the upper limit value, the process proceeds to step S205, and the N stage is selected as a new target gear stage.

  On the other hand, if it is determined in step S204 that the post-shift virtual engine rotation speed is greater than the upper limit value, the process proceeds to step S206, and the next higher gear is set as a new N (N = N + 1). Then, the virtual engine rotational speed at the new N stage is determined (step S203), and it is determined whether the virtual engine rotational speed is equal to or lower than the upper limit value (step S204). Is selected as a target gear stage (step S205).

  In this way, the gear speed at which the virtual engine rotation speed after the shift is less than or equal to the upper limit value is sequentially searched from the starting speed +1 to the high speed gear side, and the gear position that initially falls below the upper limit value is searched for as the new target gear. Select as step. That is, the lowest gear stage is selected as a new target gear stage from among the gear stages at which the virtual engine rotation speed does not exceed the upper limit value. Note that if it is determined in step S202 that the N speed ≧ the highest speed gear speed without obtaining a gear speed at which the virtual engine rotation speed is equal to or lower than the upper limit value, the process returns to step S201, and the start speed +1 speed is set again appropriately. The search for the correct target gear stage will begin.

  As described above, according to the automatic transmission control device of the second embodiment, the engine rotation speed after the shift is in an appropriate range (greater than the lower limit value and less than or equal to the upper limit value) based on the output shaft rotation speed of the transmission 3. Therefore, it is possible to select an appropriate target gear stage even during the shift control.

  In addition, this invention is not limited to the Example mentioned above.

  For example, the TMCU 9 is not limited to the one that always shifts according to the low fuel consumption mode. For example, normally, when the transmission 3 is shifted according to a map that defines the range of each gear stage based on the engine speed and the accelerator opening, and a predetermined condition is satisfied (for example, the driver is in the low fuel consumption mode). The shift control according to the low fuel consumption mode may be performed only when the start switch is turned on.

It is the schematic of the automatic transmission control apparatus which concerns on the Example of this invention. It is a graph explaining the engine output reduction control at the time of shifting. 3 is a flowchart illustrating control contents of the first embodiment. 6 is a flowchart illustrating control contents according to the second embodiment. 6 is a flowchart illustrating control contents according to the second embodiment. It is a figure for demonstrating the shift control by a low fuel consumption mode. It is a figure for demonstrating the state which the vehicle speed reduced during gear shifting.

Explanation of symbols

1 Engine 2 Clutch 3 Transmission 6 ECU (Engine Control Means)
7 Engine rotation sensor 9 TMCU (shift control means, clutch control means)
28 Output shaft sensor

Claims (5)

A shift control means for selecting a target gear stage based on at least the engine speed and automatically shifting the transmission to the target gear stage; a clutch control means for controlling connection / disconnection of the clutch in accordance with the shift of the transmission; The engine output is controlled based on the accelerator pedal opening except when the machine is shifting, and at the time of shifting, the control accelerator opening is independent of the accelerator pedal opening before the clutch is disengaged by the clutch control means. After the shift operation of the transmission is completed, the control accelerator opening is raised so as to approach the accelerator pedal opening, and the control accelerator is engaged after the clutch is engaged. Engine control means for returning to engine output control based on the accelerator pedal opening when the opening and the accelerator pedal opening match,
The shift control means is configured such that the difference between the control accelerator opening and the accelerator pedal opening is equal to or greater than a predetermined value within a period in which the engine control means executes engine output control based on the control accelerator opening. is minimum required for to calculate the virtual engine rotational speed after the shift in the current target gear position based on the output shaft rotational speed of the transmission, the vehicle after shifting to the current target gear position is not stall When the maximum torque falls below the required torque, a gear stage lower than the current target gear stage is selected as a new target gear stage. An automatic transmission control device characterized by: The shift control means prohibits selection of the new target gear stage when the maximum torque is equal to or greater than the required torque, and on the other hand, when the maximum torque falls below the required torque, the new target gear stage. 2. The automatic transmission control device according to claim 1 , wherein the prohibition of selection of the gear is released and a gear lower than the current target gear is selected as a new target gear . A shift control means for selecting a target gear stage based on at least the engine speed and automatically shifting the transmission to the target gear stage; a clutch control means for controlling connection / disconnection of the clutch in accordance with the shift of the transmission; The engine output is controlled based on the accelerator pedal opening except when the machine is shifting, and at the time of shifting, the control accelerator opening is independent of the accelerator pedal opening before the clutch is disengaged by the clutch control means. After the shift operation of the transmission is completed, the control accelerator opening is raised so as to approach the accelerator pedal opening, and the control accelerator is engaged after the clutch is engaged. Engine control means for returning to engine output control based on the accelerator pedal opening when the opening and the accelerator pedal opening match,
The shift control means is configured such that the difference between the control accelerator opening and the accelerator pedal opening is equal to or greater than a predetermined value within a period in which the engine control means executes engine output control based on the control accelerator opening. Calculates a virtual engine rotational speed after shifting at the current target gear stage based on the output shaft rotational speed of the transmission, and if the virtual engine rotational speed is equal to or lower than a predetermined lower limit value, a new target gear stage is calculated. An automatic transmission control device characterized by selecting a gear stage lower than the current target gear stage . Upper Symbol shift control means, if the virtual engine rotational speed is less than the lower limit, based on the output shaft rotational speed of the transmission, the virtual engine rotation speed after shifting to each gear position of the transmission 4. The automatic shift control device according to claim 3, wherein the lowest gear stage is selected as the new gear stage among the gear stages whose virtual engine rotation speed does not exceed a predetermined upper limit value . The automatic shift control device according to any one of claims 1 to 4, wherein the shift control means automatically shifts the transmission to a gear stage that can travel with the lowest fuel consumption within a range in which the vehicle does not stall .

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