JP2006336714A - Automatic shift control device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an automatic shift control device capable of improving the fuel economy of a vehicle. <P>SOLUTION: This transmission control device automatically shifts a transmission 3 having a plurality of shift stages different in power transmission efficiency from each other. The transmission control device comprises a fuel consumption calculation means 9 calculating a fuel consumption at which a present engine output is maintained for each shift stage of the transmission 3 based on the operating state of an engine 1 and a predetermined fuel consumption map, a correction means 9 correcting the fuel consumption at each shift stage calculated by the fuel consumption calculation means 9 based on a difference in power transmission efficiency between the shift stages, and a shift control means 9 comparing the fuel consumption for each shift stage obtained after correcting it by the correction means 9, selecting, as a target shift stage, the shift stage with the minimum fuel consumption in such a range that the vehicle is not stalled, and shifting the transmission 3 to the target shift stage. <P>COPYRIGHT: (C)2007,JPO&INPIT

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 a vehicle does not stall.

  In an automatic shift control device that automatically shifts a transmission, the transmission gear stage is referred to as a low fuel consumption mode that shifts to a gear stage that is determined to have the lowest fuel consumption rate within a range in which the vehicle does not stall. A device that executes shift control has been proposed (see, for example, Patent Document 1).

  The outline of the shift control content in the low fuel consumption mode will be described with reference to FIG.

  In FIG. 4, the horizontal axis represents the engine rotation speed, and the vertical axis represents the net average effective pressure Pme (corresponding to engine torque). A diagram indicated by a solid line A in FIG. 4 is an equal fuel consumption diagram (fuel consumption rate map) 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 lower the fuel consumption rate, and conversely, the closer to the outer line, the higher the fuel consumption rate. 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 engine output necessary for steady running in the current state) is determined based on the driving state of the vehicle, and the equal horsepower is determined. A diagram C is created. 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 required torque T (N) required to maintain the current operating state at the current gear stage N is calculated, and the required torque T (N) and the engine rotational speed R (N) are calculated. Based on this, an equal horsepower diagram C is created. In FIG. 4, 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 necessary torque required to maintain the current engine output after the shift is determined for each gear stage. In other words, in FIG. 4, 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 engine output at the N + 1 stage is T (N + 1). Further, the virtual engine rotation speed after the transmission is shifted up two stages from the current gear stage N is R (N + 2), and the torque required to maintain the current engine output at N + 2 stage is T (N + 2). is there. In FIG. 4, only the current gear stage N to N + 2 are shown, but the virtual engine rotational speed R and the required torque T after the shift are determined for all the gear stages of the transmission. The fuel consumption rate is determined for each gear stage of the transmission based on the virtual engine rotation speed R, the required torque T, and the iso-fuel consumption diagram A.

  Next, only the gear stage in which the required torque T is equal to or less than the maximum torque B of the engine is determined as a selectable gear stage. This is because if the required torque T is shifted to a gear stage that is larger than the maximum torque B of the engine, the vehicle will stall after the shift. Then, the gear stage having the lowest fuel consumption rate 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. 4, 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 consumption rates of both are compared. Here, since the fuel consumption rate is lower in the N + 1 stage than in the current gear stage N, the transmission is shifted up to the N + 1 stage.

  As described above, in the low fuel consumption mode, the vehicle is reduced in fuel consumption by shifting the transmission to a gear stage having the lowest fuel consumption rate of the engine.

JP-A-11-082084 JP 2003-291684 A

  Incidentally, the actual fuel consumption of a vehicle depends not only on the fuel consumption rate determined by the engine alone, but also on the power transmission efficiency of the transmission. Therefore, in the conventional automatic transmission control device that selects the target gear stage by comparing only the fuel consumption rate of the engine, it is possible that the fuel efficiency of the vehicle cannot be sufficiently improved in a transmission having different power transmission efficiency depending on the gear stage. There is sex.

  For example, the transmission includes a non-directly connected gear stage that transmits the power of the input shaft to the output shaft through the transmission gear, and a direct connection gear stage that directly transmits the power of the input shaft to the output shaft without using the transmission gear. In this case, the power transmission efficiency is better in the direct gear stage than in the non-direct gear stage. Therefore, in the equi-horsepower diagram C in FIG. 4, even if the direct consumption gear stage and the non-direct connection gear stage located on the same line have the same fuel consumption rate, the actual fuel consumption of the vehicle is higher in the direct connection gear stage. Get better.

  As described above, when shifting gears having gear stages having different power transmission efficiencies, it is impossible to accurately determine the fuel efficiency of the vehicle by comparing only the fuel consumption rate of the engine.

  In other words, in the conventional automatic transmission control device, the target gear stage is selected by comparing only the fuel consumption rate determined by the engine alone, so there is a possibility that the gear stage with the best fuel efficiency of the vehicle may not be selected, which improves the fuel efficiency of the vehicle There is a concern that this cannot be fully achieved.

  SUMMARY OF THE INVENTION Accordingly, an object of the present invention is to provide an automatic transmission control device that can solve the above-described problems and reliably improve fuel efficiency even in a vehicle having a transmission having a plurality of gear stages having different power transmission efficiency. It is to provide.

  In order to achieve the above object, the present invention provides an engine operating state and a predetermined fuel consumption rate map in a shift control device that automatically shifts a transmission having a plurality of gear stages having different power transmission efficiencies. The fuel consumption rate calculation means for calculating the fuel consumption rate when the current engine output is maintained for each gear stage of the transmission, and the gear stages calculated by the fuel consumption rate calculation means. The correction means for correcting the fuel consumption rate of the vehicle based on the difference in power transmission efficiency between the gear stages and the corrected fuel consumption rate of the gear stages corrected by the correction means A gear stage having the smallest fuel consumption rate within a range in which the vehicle does not stall is selected as a target gear stage, and shift control means for shifting the transmission is provided at the target gear stage.

  The correction means includes a correction coefficient predetermined for each gear stage based on a difference in power transmission efficiency between the gear stages to the fuel consumption rate of each gear stage calculated by the fuel consumption rate calculation means. To correct the fuel consumption rate of each gear stage so that the value of the gear stage with good power transmission efficiency is smaller than the value of the gear stage with poor power transmission efficiency. It may be set to.

  The transmission includes a non-directly connected gear stage that transmits power of the input shaft to the output shaft via a transmission gear, and a direct connection gear stage that transmits power of the input shaft to the output shaft without passing through the transmission gear. And the correction coefficient of the direct gear stage may be set smaller than the correction coefficient of the non-direct gear stage.

  The transmission includes a non-directly connected gear stage that transmits power of the input shaft to the output shaft via a transmission gear, and a direct connection gear stage that transmits power of the input shaft to the output shaft without passing through the transmission gear. And the correction means corrects the fuel consumption rate of each gear stage calculated by the fuel consumption rate calculation means by multiplying only the fuel consumption rate of the directly connected gear stage by a correction coefficient less than 1. The fuel consumption rate of the non-directly connected gear stage may not be corrected.

  According to the present invention, even in a vehicle having a transmission having a plurality of gear stages having different power transmission efficiencies, an excellent effect that fuel efficiency can be reliably improved is exhibited.

  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 apparatus according to the present embodiment automatically shifts a multi-stage transmission 3 (here, a forward six-stage transmission) connected to a diesel engine 1 mounted on a vehicle such as a truck via a clutch 2. .

  The engine 1 is controlled by an engine control means (ECU) 6. The ECU 6 basically operates the engine from the detected values of the engine rotation sensor 7 for detecting the rotation speed of the engine 1 and the accelerator opening sensor 8 for detecting the opening of the accelerator pedal 5 (engine rotation speed and engine speed). Load) is read, and the fuel injection timing and fuel injection amount (engine output) of the engine 1 are controlled based on the engine operating state.

  The clutch 2 and the transmission 3 are automatically controlled by a TMCU (shift 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 the present 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), and the detected value of the clutch stroke sensor 14 is transmitted to the ECU 6 and the TMCU 9.

  As shown in FIG. 2, the transmission 3 includes an input shaft 21, an output shaft 22 disposed coaxially with the input shaft 21, and a countershaft 24 disposed parallel to these. The input shaft 21 is provided with an input main gear 25. A first speed main gear M1, a second speed main gear M2, a third speed main gear M3, a fourth speed main gear M4, and a reverse main gear MR are respectively supported on the output shaft 22, and a sixth speed A main gear M6 is fixed. The auxiliary shaft 24 has an input auxiliary gear 26 that meshes with the input main gear 25, a first-speed auxiliary gear C1 that meshes with the first-speed main gear M1, a second-speed auxiliary gear C2 that meshes with the second-speed main gear M2, and 3 A third speed sub gear C3 meshing with the speed main gear M3, a fourth speed sub gear C4 meshing with the fourth speed main gear M4, and a reverse sub gear CR meshing with the reverse main gear MR via the idle gear IR are fixed. In addition, a 6-speed sub gear C6 that meshes with the 6-speed main gear M6 is pivotally supported.

  According to this transmission 3, when the sleeve S / R1 spline-engaged with the hub H / R1 fixed to the output shaft 22 is spline-engaged with the dog DR of the reverse main gear MR, the output shaft 22 rotates reversely, and the sleeve When S / R1 is spline-engaged with the dog D1 of the first-speed main gear M1, the output shaft 22 rotates at the first speed. Similarly, when the sleeve S / 23 that is spline-engaged with the hub H / 23 fixed to the output shaft 22 is spline-engaged with the dog D2 of the second-speed main gear M2, the output shaft 22 rotates at a speed equivalent to the second speed, and the sleeve S / 23 is spline-engaged with the dog D3 of the third speed main gear M3, the output shaft 22 rotates at the third speed. Further, when the sleeve S / 45 spline-engaged with the hub H / 45 fixed to the output shaft 22 is spline-engaged with the dog D4 of the 4-speed main gear M4, the output shaft 22 rotates at a speed equivalent to the fourth speed. When the sleeve S6 spline-engaged with the hub H6 fixed to the auxiliary shaft 24 is spline-engaged with the dog D6 of the sixth-speed auxiliary gear C6, the output shaft 22 rotates at the sixth speed.

  In these cases, power is transmitted to the output shaft 22 from the input shaft 21 via the main gears M1 to M4, M6, MR and the auxiliary gears C1 to C4, C6, CR that form a transmission gear. That is, the transmission 3 is geared into the non-directly connected gear stage. In the present embodiment, all gears other than the fifth speed described later are non-directly connected gear stages.

  Further, when the sleeve S / 45 is spline-engaged with the dog D5 of the input main gear 25, the output shaft 22 rotates at the fifth speed. In this case, power is directly transmitted from the input shaft 21 to the output shaft 22 without passing through the transmission gear. That is, the transmission 3 is geared into the directly connected gear stage, and the power transmission efficiency of the directly connected gear stage is improved compared to the non-directly connected gear stage by the amount not passing through the transmission gear.

  Thus, the transmission 3 according to the present embodiment includes a plurality of gear stages having different power transmission efficiencies.

  Returning to FIG. 1, 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 the output shaft 22 (see FIG. 2), and the detection value of the output shaft sensor 28 is transmitted to the TMCU 9. The TMCU 9 calculates the vehicle speed based on the detection value of the output shaft sensor 28.

  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 gear disengagement / gear-in of the transmission 3, and then 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 of the present embodiment performs the shift control as described below.

  First, the TMCU 9 obtains a virtual engine operation state (specifically, a virtual torque and a virtual engine rotation speed) when it is assumed that the current engine output is maintained after the shift for each gear stage of the transmission 3. Next, based on the virtual engine operating state and the current engine operating state and a predetermined fuel consumption rate map, the TMCU 9 assumes that the current engine output has been maintained after the shift and the virtual speed of each gear stage. Obtain the fuel consumption rate and the fuel consumption rate of the current gear stage.

  Next, the TMCU 9 corrects the calculated virtual fuel consumption rate of each gear stage and the fuel consumption rate of the current gear stage based on the difference in power transmission efficiency between the gear stages.

  After the correction, the TMCU 9 compares the corrected fuel consumption rates of all the corrected gears, and within a range where the vehicle does not stall (that is, in a gear where the virtual torque does not exceed the maximum torque of the engine). ) The gear stage having the smallest fuel consumption rate is selected as the target gear stage, and the transmission 3 is automatically shifted to the target gear stage.

  Therefore, in the present embodiment, the TMCU 9 calculates the fuel consumption rate when the current engine output is maintained for each gear stage of the transmission 3 based on the engine operating state and the predetermined fuel consumption rate map. A fuel consumption rate calculation means for calculating and a correction means for correcting the calculated fuel consumption rate of each gear stage based on the difference in power transmission efficiency between the gear stages.

  The automatic transmission control device of this embodiment is characterized in that the gear stage to be shifted is selected in consideration of not only the fuel consumption rate of the engine alone but also the power transmission efficiency of each gear stage.

  Hereinafter, this point will be described with reference to the flowchart of FIG. In the following description, the fuel consumption rate in the fuel consumption rate map (isofuel consumption diagram, for example, see diagram A in FIG. 4) stored in advance in the TMCU 9 is set as the standard fuel consumption rate, and compared when selecting the target gear stage. The actual fuel consumption rate is defined as the actual fuel consumption rate. In the flowchart of FIG. 3, the TMCU 9 executes each gear stage for every gear stage every predetermined period.

  First, in step S0, a gear stage (hereinafter referred to as a target gear stage) for which an actual fuel consumption rate is calculated, a virtual torque and a virtual engine rotation speed of the target gear stage are input to TMCU9.

  Next, in step S1, the TMCU 9 determines whether or not the input target gear stage is a directly connected gear stage. If it is determined in step S1 that the target gear stage is a directly connected gear stage, the process proceeds to step S2.

  In step S2, the standard fuel consumption rate (map value) of the target gear stage is read from the fuel consumption rate map stored in advance in the TMCU 9 based on the virtual torque and the virtual engine rotation speed. Thereafter, the actual fuel consumption rate is calculated by multiplying the standard fuel consumption rate by a preset correction coefficient. The correction factor is determined by converting the difference in transmission efficiency between the direct gear stage and the non-direct gear stage into the fuel consumption rate. For example, when the vehicle is driven at the direct gear stage, When a fuel efficiency improvement of 2% is expected (can be achieved), assuming that the correction coefficient for the non-direct gear stage is 1, the correction coefficient for the direct gear stage is 0.98. Therefore, the actual fuel consumption rate of the directly connected gear stage is obtained by multiplying the standard fuel consumption rate by 0.98. As described above, in the case of the directly connected gear stage, the standard fuel consumption rate is corrected to be reduced by an amount corresponding to the fuel efficiency improvement as a vehicle with respect to the non-directly connected gear stage.

  On the other hand, if it is determined in step S1 that the target gear stage is not a directly connected gear stage, that is, if it is determined that the target gear stage is a non-directly connected gear stage, the process proceeds to step S3. In step S3, the standard fuel consumption rate (map value) of the target gear stage is read from the fuel consumption rate map based on the virtual torque and the virtual engine speed, and the standard fuel consumption rate is directly used as the actual fuel consumption rate of the non-directly connected gear stage. To do. As described above, in the present embodiment, the correction coefficient for the non-directly connected gear stage is set to 1, and substantial correction of the standard fuel consumption rate is not executed.

  As described above, after the actual fuel consumption rate of each gear stage is calculated, the target gear stage is selected by comparing the actual fuel consumption rates.

  As described above, according to the automatic transmission control apparatus of the present embodiment, the correction coefficient of the fuel consumption rate of the direct connection gear stage is made smaller than the correction coefficient of the fuel consumption rate of the non-direct connection gear stage. The difference in power transmission efficiency from the non-directly connected gear stage is reflected in the fuel consumption rate. As a result, in addition to the fuel consumption rate of the engine alone, the power transmission efficiency of the transmission is also taken into consideration, so that it is possible to shift to the most appropriate gear stage and further improve fuel efficiency.

  In addition, this invention is not limited to the above-mentioned embodiment, Various modifications and application examples can be considered.

  For example, in this embodiment, the direct gear stage is corrected based on the non-direct gear stage. However, the present invention is not limited to this, and the non-direct gear stage is corrected based on the direct gear stage. May be.

  It is also conceivable that the correction coefficient is set to a different value depending on the rotational speed of the input shaft and output shaft of the transmission. For example, when the rotational speed of the input shaft of the transmission increases, the difference in power transmission efficiency between the non-direct gear stage and the direct gear stage increases (the power transmission efficiency of the non-direct gear stage deteriorates). It is also conceivable to reduce the gear stage correction coefficient in accordance with the rotational speed.

  It is also conceivable to store a corrected fuel consumption rate map that has been corrected in advance (multiplied by a correction coefficient) in a TMCU or the like separately from the fuel consumption rate map.

It is the schematic of the automatic transmission control apparatus which concerns on one Embodiment of this invention. It is the schematic of the transmission of this embodiment. It is a figure for demonstrating the control content of a correction | amendment means. It is a figure for demonstrating the shift control by a low fuel consumption mode.

Explanation of symbols

1 Engine 2 Clutch 3 Transmission 5 Accelerator Pedal 6 ECU
7 Engine rotation sensor 8 Accelerator opening sensor 9 TMCU (Fuel consumption rate calculation means, correction means, shift control means)
28 Output shaft sensor

Claims (4)

In a shift control device that automatically shift-controls a transmission having a plurality of gear stages having different power transmission efficiency,
A fuel consumption rate calculating means for calculating a fuel consumption rate for each gear stage of the transmission based on the engine operating state and a predetermined fuel consumption rate map;
Correction means for correcting the fuel consumption rate of each gear stage calculated by the fuel consumption rate calculation means based on the difference in power transmission efficiency between the gear stages;
The corrected fuel consumption rate of each gear stage corrected by the correction means is compared, and the gear stage with the lowest fuel consumption rate is selected as the target gear stage within a range where the vehicle does not stall, and the target gear stage is selected. An automatic transmission control device comprising a transmission control means for shifting the transmission. The correction means includes a correction coefficient predetermined for each gear stage based on a difference in power transmission efficiency between the gear stages to the fuel consumption rate of each gear stage calculated by the fuel consumption rate calculation means. To correct the fuel consumption rate of each gear stage,
The automatic shift control device according to claim 1, wherein the correction coefficient is set so that a value of a gear stage having good power transmission efficiency is smaller than a value of a gear stage having poor power transmission efficiency. The transmission includes a non-directly connected gear stage that transmits power of the input shaft to the output shaft via a transmission gear, and a direct connection gear stage that transmits power of the input shaft to the output shaft without passing through the transmission gear. Have
3. The automatic transmission control device according to claim 2, wherein the correction coefficient of the directly connected gear stage is set smaller than the correction coefficient of the non-directly connected gear stage. The transmission includes a non-directly connected gear stage that transmits power of the input shaft to the output shaft via a transmission gear, and a direct connection gear stage that transmits power of the input shaft to the output shaft without passing through the transmission gear. Have
The correction means corrects the fuel consumption rate of each gear stage calculated by the fuel consumption rate calculation means by multiplying only the fuel consumption rate of the directly connected gear stage by a correction coefficient less than 1, and the non-direct connection 2. The automatic transmission control device according to claim 1, wherein the fuel consumption rate of the gear stage is not corrected.

Images