JP2005265147A - Automatic transmission control device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an automatic transmission control device for providing necessary acceleration, when the transmission to a gear speed wherein a fuel consumption rate is minimized within a range where a vehicle does not stall, an accelerator pedal is depressed up to an approximately fully open condition to balance a maximum driving force and travel resistance are balanced to be a constant vehicle speed. <P>SOLUTION: The automatic transmission control device comprises: basic control means 9a, S24-S26 for performing the transmission to the gear speed wherein the fuel consumption rate is minimized within the range where the vehicle does not stall; and correction control means 9b, S22, S23 for setting a gear other than a present gear N as gears to be shifted by the basic control means 9a, S24-S26, when accelerator opening is predetermined opening or more and a state where change in vehicle speed is a predetermined value or less has continued for a predetermined time or more in the present gear speed N shifted by the basic control means 9a, S24-S26. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to an automatic transmission control apparatus that performs transmission control to a gear stage that minimizes a fuel consumption rate while preventing a vehicle from stalling.

  As an automatic shift control device for a transmission for a vehicle, a shift control referred to as a low fuel consumption mode for shifting the gear stage of the transmission to a gear stage having the smallest fuel consumption rate within a range in which the vehicle does not stall is executed. Have been proposed (for example, Patent Documents 1 and 2, etc.), and the present inventor has developed the following automatic shift control device of this type.

  As shown in FIG. 5, this automatic transmission control device uses a constant fuel consumption map A, a maximum torque diagram B, and a constant horsepower diagram C of the engine, and a gear that has the smallest fuel consumption rate while preventing vehicle stall. Shift control is performed in stages. In the figure, the horizontal axis represents the engine speed (rpm), and the vertical axis represents the net average effective pressure Pme corresponding to torque. The equal fuel consumption map A means that the fuel consumption rate SFC is the same if it is on the same line, and the fuel consumption improves as it approaches the inner line, and conversely, the fuel consumption deteriorates as it approaches the outer line. The maximum torque diagram B shows the maximum torque that the engine exhibits when the accelerator pedal is substantially fully opened.

  The equal horsepower diagram C obtains the minimum necessary torque for maintaining the current driving state of the vehicle, that is, for steady running in the current state, based on the torque currently generated by the engine. The required horsepower is obtained by multiplying the required torque by the current engine speed, and is created based on this required horsepower. Specifically, after obtaining the required horsepower, the engine speed at each gear stage relative to the current gear stage is calculated based on the gear ratio of each gear stage, and the required horsepower is calculated at each gear stage. To obtain the required torque at each gear stage, and connect the plot points of the required torque at each gear stage and the engine rotation speed to obtain the equihorsepower diagram C.

  Then, among the gear stages on the equi-horsepower diagram C, only the gear stage whose required torque after the shift is equal to or less than the maximum torque is selected as a gear stage that can be shifted. This is because if the required torque after the shift is larger than the maximum torque, the vehicle will stall after the shift. Then, the gear stage having the smallest fuel consumption rate among the selected gear stages is specified as the target gear stage, and the gear is shifted to this gear stage. As a result, the gear is shifted to the smallest gear speed within a range where the vehicle does not stall.

  In the example shown in the figure, N, N-1 and N-2 stages are selected as gear stages that can be changed, and the speed is changed to the N stage with the lowest fuel consumption rate.

Japanese Patent Publication No. 5-14133 Japanese Patent No. 3460528

  Here, as shown in the figure, when the required torque at the gear stage (N stage) after the shift becomes equal to the maximum torque, that is, the necessary torque necessary for maintaining the current operating state and preventing the stall is When the accelerator pedal is almost fully opened and becomes equal to the maximum torque generated, the following problem occurs. In other words, in this case, the marginal driving force (maximum torque-necessary torque) is zero, and if the necessary torque is equal to or greater than the maximum torque, the current gear stage is stalled, so the required torque is equal to the maximum torque. There is no such downshift. Therefore, at this time, the vehicle continues to travel at a constant speed without being shifted although the accelerator pedal is substantially fully open, and the drive feeling is deteriorated.

  In this situation, there is some marginal driving force in the gear stage shifted (shifted up) by the above fuel efficiency mode on a flat road, and the driving resistance increases as the vehicle approaches the uphill road, causing the driver to decelerate the vehicle. It can happen when you depress the accelerator pedal almost fully open. In other words, if there is a situation where the driving force (maximum torque) and the running resistance (necessary torque) are balanced when the accelerator pedal is almost fully open due to the relationship between the gear stage and the climbing slope, acceleration will occur even if the accelerator pedal is fully depressed. A situation occurs in which neither shifting nor shifting occurs. This deteriorates the drive feeling particularly at low vehicle speeds.

  The object of the present invention is that when the vehicle shifts to a gear position where the fuel consumption rate is the smallest within a range where the vehicle does not stall, the accelerator pedal is depressed to the fully open position, and the maximum driving force and the running resistance are balanced to achieve a constant vehicle speed. In this case, an automatic transmission control device is provided which can obtain the necessary acceleration.

  In order to achieve the above object, the present invention comprises a basic control means for shifting to a gear stage at which the fuel consumption rate is determined to be the smallest within a range where the vehicle does not stall, and a current gear stage shifted by the basic control means. When the accelerator opening is greater than or equal to the predetermined opening and the change in vehicle speed is less than or equal to the predetermined value for a predetermined time or longer, the correction control is performed so that a gear other than the current gear is the gear to be shifted by the basic control means. Means.

  In addition, the accelerator opening is greater than or equal to a predetermined opening in the basic control means that shifts to the gear stage where the fuel consumption rate is determined to be the smallest within the range where the vehicle does not stall, and the current gear stage that is shifted by the basic control means. When the vehicle speed change continues below a predetermined value for a predetermined time or longer, the fuel consumption rate of the current gear stage is virtually replaced with the maximum value, and the fuel consumption rate of the current gear stage is stored in the basic control means. And a correction control means for determining that the speed is larger than the other gear stages.

  In addition, the accelerator opening is greater than or equal to a predetermined opening in the basic control means that shifts to the gear stage where the fuel consumption rate is determined to be the smallest within the range where the vehicle does not stall, and the current gear stage that is shifted by the basic control means. And a correction control means for shifting down one step from the current gear stage in preference to the shift control by the basic control means when the vehicle speed change continues for a predetermined time or longer. .

  According to the present invention, when the vehicle is shifted to a gear position where the fuel consumption rate is the smallest within a range where the vehicle does not stall, the accelerator pedal is depressed to a substantially full open state, and the maximum driving force and the running resistance are balanced to obtain a constant vehicle speed. In this case, the shift control can be performed so as to obtain the necessary acceleration.

  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 (from the outputs of the engine rotation sensor 7 that detects the rotation speed rpm of the engine 1 and the accelerator opening sensor 8 that detects the opening of the accelerator pedal 5. Engine load) is read, and the fuel injection amount and fuel injection timing (engine output) are controlled mainly based on these.

  The clutch 2 and the transmission 3 are automatically controlled by a TMCU (basic control means) 9. 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.

  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.

  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 TMCU 9 is a component that characterizes the present embodiment, and includes basic control means 9a and correction control means 9b that operate in the low fuel consumption mode.

  The basic control means 9a shifts to a gear stage that is determined to have the lowest fuel consumption rate while maintaining the current driving state of the vehicle, that is, within a range where the vehicle does not stall. Since the shift control by the basic control means 9a is the same as that described above with reference to FIG. 5, the detailed description is omitted, but the outline is as follows.

  That is, using the equal fuel consumption map A, the maximum torque diagram B, and the equal horsepower diagram C shown in FIG. 5, the gears on the equal horsepower diagram C that have a maximum torque larger than the required torque are selected. Among these, the gear stage having the smallest fuel consumption rate is specified as the target gear stage, and the speed is changed to the target gear stage. As a result, the speed is changed to a gear position where the fuel consumption rate is minimized within a range in which the vehicle does not stall.

  When the state where the accelerator opening is equal to or larger than the predetermined opening and the change in the vehicle speed is equal to or smaller than the predetermined value is continued for a predetermined time or longer in the current gear stage shifted by the basic control means 9a, the correction control means 9b The gear stage other than the stage is used as the gear stage to be shifted by the basic control means 9a.

  According to the correction control means 9b and the basic control means 9a, the following shift control is performed. In other words, at the current gear stage, that is, the gear stage that achieves the lowest fuel consumption within the range where the vehicle does not stall, the running resistance (necessary torque) of the vehicle balances the maximum driving force (maximum torque) when the accelerator pedal is almost fully opened to maintain a constant vehicle speed. In this case, since the gear stage other than the current gear stage is set as the gear to be shifted by the basic control means 9a by the correction control means 9b, the basic control means 9a changes the current gear stage to the next to the current gear stage. The gear is shifted (shifted down) to a gear with good fuel efficiency and the vehicle does not stall.

  Although this gear stage is slightly inferior in fuel efficiency to the current gear stage, there is a surplus driving force (maximum torque-required torque), so acceleration according to the intention to accelerate, that is, acceleration depending on the depression of the accelerator pedal is possible, and drive feeling is improved. To do.

  The shift control in the low fuel consumption mode by the basic control means 9a and the correction control means 9b is performed based on the flowcharts shown in FIGS.

  FIG. 2 is a flowchart of the acceleration / deceleration timer that counts the predetermined time.

  In step S1, it is determined whether the current gear stage is the target gear stage (the gear stage specified by the basic control means 9a). If no, it is not the low fuel consumption mode, so the process proceeds to step S8 and the timer is set to zero. If yes, it is in the low fuel consumption mode, so the process proceeds to step S2.

  In step S2, it is determined whether the accelerator opening exceeds a predetermined opening (for example, 90%). If no, the engine is not demonstrating the maximum torque, and the maximum torque (driving force) and the required torque (running resistance) cannot be balanced as in the N stage in FIG. The timer is set to zero. If yes, since the above situation can be established, the process proceeds to step S3.

  In step S3, the fluctuation a of the vehicle speed per second is calculated based on the detection value of the vehicle speed sensor or the like, and the process proceeds to step S4.

  In step S4, it is determined whether the vehicle speed fluctuation a is less than a predetermined value (for example, 0.5 km / h). If no, the running resistance of the vehicle and the driving force are not balanced, and there is a surplus driving force left, so the process proceeds to step S8 and the timer is set to zero. If yes, the running resistance and the driving force are substantially balanced, and the state is in the N stage in FIG.

  In step S5, it is determined whether the engine speed (rpm) is less than a predetermined speed (for example, 900 rpm). If no, that is, if the engine speed is 900 rpm or more, the process proceeds to step S8, and the timer is set to zero. This is because when the engine rotation speed is 900 rpm or more and the timer is incremented in step S7 and a shift down described later is performed, the fuel consumption is significantly deteriorated. If yes, that is, if the engine speed is less than 900 rpm, the fuel consumption deterioration associated with the downshift will not be noticeable, so the process proceeds to step S6.

  In step S6, it is determined whether the vehicle speed is less than a predetermined vehicle speed (for example, 50 km / h). If no, that is, if the vehicle speed is 50 km / h or more, the process proceeds to step S8, and the timer is set to zero. This is because when the vehicle speed is 50 km / h or more and a downshift described later is performed, the fuel consumption is significantly deteriorated. If the answer is yes, that is, if the vehicle speed is less than 50 km / h, the fuel consumption deterioration associated with the downshift does not become significant, so the process proceeds to step S7.

  In step S7, the timer is incremented (added).

  Thus, the low fuel consumption mode by the basic control means 9a is executed (step S1), there is an intention of acceleration and the maximum driving force can be exhibited (step S2), and the running resistance and the maximum driving force are When the engine speed is less than 900 rpm (step S5) and all the conditions of the vehicle speed are less than 50 km / h (step S6) are satisfied, the timer count is continued.

  It should be noted that a determination unit may be added upstream from step S7 when the current gear stage is greater than or equal to a predetermined gear stage, and to step S8 when the current gear stage is less than the predetermined gear stage. This is because when a shift down described later is performed at a higher gear than a predetermined gear, the fuel consumption is remarkably deteriorated, so that a shift down described later is performed only at a lower gear below the predetermined gear.

  Further, the predetermined opening 90%, the predetermined value 0.5 km / h, the predetermined rotational speed 900 rpm, and the predetermined vehicle speed 50 km / h are all examples, and are not limited to these numerical values.

  Next, FIG. 3 is a flowchart for selecting a shift target gear according to the traveling state of the vehicle.

  In step S11, it is determined whether the time count of the timer exceeds a predetermined time (for example, 3 seconds). If yes, the driver's willingness to accelerate and the driving resistance is balanced with the maximum torque, the acceleration is impossible and the driving time is almost constant for more than 3 seconds. Since it has deteriorated, it goes to step S12.

  In step S12, the shift target gear is set to the current gear stage-1 to the current gear stage in order to allow a downshift for realizing acceleration. Here, the reason why the low-speed gear stage below the current gear stage -2 is removed from the gear stage to be shifted is that the fuel consumption rate generally deteriorates as the number of shift-down gear stages decreases to the low-speed gear stage. This is for avoiding that the deterioration of the temperature becomes remarkable. However, in the engine having the characteristic that the fuel consumption rate does not deteriorate so much even at the low speed side gear stage below the current gear stage-2, the gear to be shifted is set to the start gear stage to the current gear stage.

  If “NO” in the step S11, that is, if the traveling resistance (required torque) and the maximum driving force (maximum torque) are balanced and the traveling time is approximately constant speed is 3 seconds or less, the process proceeds to the step S13. In step S13, it is determined whether the vehicle is decelerating. If no, that is, if the vehicle is accelerating, the process proceeds to step S14. In step S14, the shift target gear is changed from the current gear to the highest gear in order to allow upshifting.

  If yes in step S13, that is, if the vehicle is decelerating, the process proceeds to step S15. In step S15, the shift target gear is changed from the start gear stage to the current gear stage in order to allow downshift.

  As described above, when the driver intends to accelerate and the time during which the maximum torque and the necessary torque are balanced and the vehicle is running at substantially constant speed continues for more than 3 seconds, the gear to be shifted is the current gear stage − 1 to the current gear stage (step S12), the gear to be shifted is from the current gear stage to the highest gear stage during acceleration (step S14), and the gear stage to be shifted is from the start gear stage to the current gear stage during deceleration. (Step S15).

  The predetermined time of 3 seconds is an example, and is not limited to this value.

  Next, FIG. 4 is a flowchart for specifying the target gear stage from among the selected gears to be shifted.

  In step S21, the fuel consumption rate SFC at the gear stage where the vehicle does not stall among the gears to be shifted selected in step S12, S14 or S15 in FIG. Obtained from FIG.

  In step S22, it is determined whether the time count of the timer incremented according to the flowchart of FIG. 2 exceeds a predetermined time (for example, 3 seconds). If yes, the driver is willing to accelerate, but the maximum torque and the required torque are balanced and the vehicle is running at approximately the same speed for more than 3 seconds. Head to S23. At this time, since step S11 becomes YES in FIG. 3, the flow proceeds to step S12, and the gears to be shifted are set to the current gear stage-1 to the current gear stage.

  Returning to FIG. 4, in step S23, the fuel consumption rate of the current gear stage is virtually maximized. And it goes to step S24. In step S24, it is determined whether there are a plurality of gear stages that minimize the fuel consumption rate. As described above, when step S22 is YES, the fuel consumption rate of the current gear stage is virtually maximized by step S23, so that the current gear stage-1 to the current gear stage, which are gears to be shifted, are used. Among them, the current gear stage-1 is the only gear stage with the lowest fuel consumption rate.

  Therefore, in step S26, the target gear stage is set to the current gear stage-1. As a result, the N-stage is shifted down by one stage from the N-stage state in FIG. 5, so that a marginal driving force is generated, acceleration according to the depression of the accelerator pedal is possible, and fuel consumption is slightly sacrificed. Improves the drive feeling of things.

  On the other hand, if NO in step S22, step S11 is NO in FIG. 3 and the flow proceeds to step S13, and the gear to be shifted is the current gear to the highest gear (step S14), or the start gear to the current gear ( Step S15). In this case, in FIG. 4, the process bypasses step S23 and proceeds to step S24.

  In step S24, it is determined whether or not there are a plurality of gear stages at which the fuel consumption rate is minimum. If yes, the highest gear stage among the plurality of gear stages is set as the target gear stage, and if no, step S26 is determined. , The only minimum fuel efficiency gear stage is set as the target gear stage. As a result, the gear is shifted to the gear stage with the best fuel efficiency while preventing the vehicle from stalling.

  As described above, in the present embodiment, in the low fuel consumption mode, the maximum driving force (maximum torque) and the running resistance (necessary torque) are balanced at the gear stage that achieves the lowest fuel consumption, in spite of the intention to accelerate. When the state where acceleration is impossible continues for a predetermined time (for example, 3 seconds), the drive feeling is improved by downshifting by one step to enable acceleration. Further, in the low fuel consumption mode, in a case other than the above-described state, the low fuel consumption is achieved by performing the shift control to the gear stage having the lowest fuel consumption within the range where the vehicle does not stall.

  In the illustrated example, steps S22 and S23 correspond to the correction control means in the claims, and steps S24 to S26 correspond to the basic control means.

  Note that 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 shift-controlled based on a map that defines the range of each gear stage based on the engine speed and the accelerator opening, and when 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 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 flowchart about determination of an acceleration / deceleration timer. It is a flowchart about determination of a transmission gear stage. It is a flowchart about determination of a target gear stage. It is a figure which shows the equal fuel consumption map A, the maximum torque diagram B, and the equal horsepower diagram C.

Explanation of symbols

1 Engine 2 Clutch 3 Transmission 5 Accelerator Pedal 6 ECU
7 Engine rotation sensor 8 Accelerator pedal opening sensor 9 TMCU
9a, S24 to S26 Basic control means 9b, S22, S23 Correction control means N Current gear stage A Fuel economy map B Maximum torque diagram C Constant horsepower diagram

Claims (3)

Basic control means for shifting to a gear stage where the fuel consumption rate is determined to be the smallest within a range in which the vehicle does not stall;
When the accelerator opening is greater than or equal to a predetermined opening and the change in vehicle speed is less than or equal to a predetermined value at a current gear speed shifted by the basic control means,
An automatic shift control device comprising: correction control means for setting a gear stage other than the current gear stage to a shift target gear stage of the basic control means. Basic control means for shifting to a gear stage where the fuel consumption rate is determined to be the smallest within a range in which the vehicle does not stall;
When the accelerator opening is greater than or equal to a predetermined opening and the change in vehicle speed is less than or equal to a predetermined value at a current gear speed shifted by the basic control means,
A correction control means that virtually replaces the fuel consumption rate of the current gear stage with a maximum value and causes the basic control means to determine that the fuel consumption rate of the current gear stage is greater than other gear stages. A feature of an automatic transmission control device. Basic control means for shifting to a gear stage where the fuel consumption rate is determined to be the smallest within a range in which the vehicle does not stall;
When the accelerator opening is greater than or equal to a predetermined opening and the change in vehicle speed is less than or equal to a predetermined value at a current gear speed shifted by the basic control means,
An automatic shift control device comprising: correction control means for shifting down one step from the current gear stage in preference to the shift control by the basic control means.

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