JP2006299814A - Vehicle driving control device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To prevent a sense of incongruity to a driver caused by a change in driving force when an engine idling speed becomes a high idling speed. <P>SOLUTION: In the case that an idle up condition is satisfied at the time of warming up operation and the high load of an air conditioner (determination in S5 or S12 is YES), a high gear stage with a low transmission gear ratio is set in S8 or S15, and also idle up control for increasing the engine idling speed is performed in S9 or S16. However, an engine speed at the time of idle up is set to generate driving force (creep torque) having the same magnitude as the normal idling time of a low speed gear stage at a low idling speed. Therefore, driving force is kept to the same magnitude regardless of idle up, and the sense of incongruity to the drive is prevented. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a drive control device for a vehicle, and more particularly to control when an engine idling engine speed is switched to a high idling engine speed during warm-up operation or high load on an air conditioner.

(a) a vehicle drive device having an engine, a fluid power transmission device, and an automatic transmission; and (b) a predetermined high-speed idle speed of the engine when a predetermined idle-up condition is satisfied. Idle speed control means for switching to the rotation speed, and (c) when the high speed idle speed is set by the idle speed control means, the gear speed of the automatic transmission is increased at a higher speed than in normal times when the idle speed is low. For example, Patent Document 1 discloses a vehicle drive control device having an idle-time gear stage setting means for switching to a side gear stage. That is, in recent years, the gear ratio of the lowest gear (first gear) tends to increase for the purpose of increasing the number of gears of an automatic transmission and improving the starting performance. When the engine speed increases, the driving force (creep force) when the accelerator is OFF becomes too large. Therefore, switching to a higher gear stage such as the second speed gear stage prevents the driving force from increasing due to idling up. .
Japanese Patent Publication No. 5-62264

  However, even when the gear stage is switched to the high speed side during idling up as described above, there is a problem that the driving force is different from that during normal idling, causing the driver to feel uncomfortable. In other words, the engine speed at the time of idling up (high speed idling speed) is determined according to the demand due to the warm-up operation or the load of the air conditioner. Although the increase can be prevented, it cannot be made the same as the driving force at the time of normal idling, and generally the driving force becomes smaller than that at the time of normal idling.

  The present invention has been made against the background of the above circumstances, and the object of the present invention is to change the driving force when the engine idling speed is set to a high idling speed, causing the driver to feel uncomfortable. It is to prevent that.

  In order to achieve such an object, the first invention provides (a) a vehicle drive device having an engine, a fluid power transmission device and an automatic transmission, and (b) a case where a predetermined idle up condition is satisfied. (I) an idle rotation speed control means for switching the idle rotation speed of the engine to a predetermined high speed idle rotation speed; and (c) when the idle rotation speed control means sets the high speed idle rotation speed, the idle rotation speed is low. In a drive control device for a vehicle having an idle gear stage setting means for switching the gear stage of the automatic transmission to a high-speed gear stage compared to a normal time, (d) the high-speed idle rotational speed is When switched to a gear stage, the same driving force as during normal idling when the idle speed is low and the low speed gear stage is set can be obtained. It is defined.

  Note that a driving force comparable to that during normal idling means that it is within a range of ± 10% with respect to a driving force during normal idling, and is preferably within a range of ± 5%. Further, the driving force changes between when the vehicle is stopped (vehicle speed = 0) and when the vehicle is creeping, and either one may be used as a reference for setting the high-speed idle rotation speed.

  According to a second aspect of the present invention, in the vehicle drive control apparatus according to the first aspect, the idle speed control means may be configured so that the idle-up condition is not satisfied while the engine is operating at the high-speed idle speed. A high idle rotation speed is maintained.

  In such a vehicle drive control device, even when the engine is operated at a high idle rotation speed even when the engine is operated at a high idle rotation speed, it is possible to switch to a high-speed gear stage. As a result, a driving force comparable to that during normal idling with a low idle gear speed and a low gear is generated, so that the driving force is substantially the same regardless of idling up, and the driver feels uncomfortable. Is prevented.

  In addition, when the idle-up condition is not satisfied while the engine is operating at a high idle speed, if the idle speed is switched to a low idle and a normal idle state with a low gear, the final drive Even if the force is the same, it is inevitable that the driving force fluctuates transiently due to a change in the operating state of the engine or a shift of the automatic transmission, causing the driver to feel uncomfortable. If the high idle speed is maintained even if the idle up condition is not satisfied, such fluctuations in the driving force are prevented, and there is no possibility of causing the driver to feel uncomfortable.

  As the automatic transmission constituting the vehicle drive device, for example, a stepped automatic transmission such as a planetary gear type or a parallel shaft type is preferably used. However, a continuously variable transmission such as a belt type or a toroidal type is used. If at least the accelerator is idle (when the driver does not request output), the gears may be shifted between a plurality of gears with different gear ratios by the idle gear setting unit. It ’s fine. The present invention may be applied only at the time of forward start by the forward gear stage, but can also be applied at the time of reverse start when having a plurality of reverse gear stages having different gear ratios.

  The engine generates power by burning fuel, and an internal combustion engine is preferably used. The fluid power transmission device may be a torque converter, a fluid coupling, or the like that can maintain the operating state of the engine even when the vehicle is stopped, transmit power to the automatic transmission, and generate driving force.

  The idle rotation speed control means can switch between a normal low-speed idle rotation speed and a high-speed idle rotation speed at the time of idle-up. For example, an electronic throttle valve or an ISC ( (Idle rotation speed control) valve, fuel injection valve and the like are configured to perform feedback control.

  For example, when the engine cooling water temperature is lower than a predetermined value and the engine needs to be warmed up, or when the air conditioner is heavy and the compressor speed is increased, the idle up condition for increasing the idle speed is to charge the battery. Various conditions can be set when the engine speed is increased.

The high-speed idle rotation speed is set so that the automatic transmission can be switched to the high-speed gear stage so that a driving force comparable to that during normal idling with a low idle rotation speed and a low-speed gear stage can be obtained. For example, it is determined in consideration of the torque characteristics of the fluid type power transmission device and the gear ratio of the automatic transmission. That is, as shown in the following equation (1), the driving force F of the vehicle is the output torque of the fluid power transmission device that is rotationally driven by the engine, that is, the input torque Tin of the automatic transmission, the gear ratio I of the automatic transmission, Since it is obtained by multiplying the coefficient α determined by the final reduction ratio of the differential gear unit and the tire diameter, etc., the input torque during normal idling is Tin1, the gear ratio of the low speed gear stage is I _LO , and the high speed side gear stage is When the gear ratio is I _HI , the high-speed idle rotation speed may be set so that the input torque Tin2 that satisfies the following equation (2) is obtained. Since the characteristic of the input torque Tin, that is, the output torque of the fluid power transmission device generally depends on the input rotational speed, that is, the engine rotational speed, the input rotational speed, that is, the engine that obtains the input torque Tin2 based on the output torque characteristic. The rotation speed may be a high idle rotation speed.
F = Tin × I × α (1)
Tin2 × I _HI ≒ Tin1 × I _LO (2)

  The high-speed idle rotation speed needs to be higher than the idle rotation speed required at the time of idle-up due to warm-up operation or a load of an air conditioner. The gear on the high speed side will be used. That is, when the gear ratio of the first speed gear stage and the gear ratio of the second speed gear stage become close due to, for example, an increase in the number of stages of the automatic transmission, the same driving force as that during normal idling at the first speed gear stage is obtained. The high-speed idle rotation speed is relatively low and may not reach the required idle rotation speed due to idle-up. In this case, the gear ratio setting means is further smaller than the second speed gear stage due to the idle gear stage setting means. By switching to the high speed side gear stage that is equal to or higher than the third speed gear stage, the high speed idle rotational speed is made equal to or higher than the required idle rotational speed. In other words, the idle gear stage setting means is such that the gear ratio of the automatic transmission and the required idle rotational speed are such that the high-speed idle rotational speed at which a driving force comparable to that during normal idling is obtained is equal to or higher than the required idle rotational speed. In consideration of the above, the high speed side gear to be switched at the time of idle-up is determined.

  In the second aspect of the invention, the engine idling speed is maintained at a high idling speed even if the idling up condition is not satisfied. In this case, for example, the driver requests the output by depressing the accelerator pedal. The idle-up control is canceled when a predetermined release condition is satisfied, such as when shift control is performed as the vehicle speed increases, or when a predetermined time has elapsed since the idle-up condition is no longer satisfied. The engine speed may be allowed to decrease to a normal low idle speed.

Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.
FIG. 1A is a skeleton diagram of a vehicle drive device 8 to which the present invention is applied. The vehicle drive device 8 includes an engine 30, a torque converter 32, and an automatic transmission 10. It is suitably used for FR vehicles that are mounted in the place). The automatic transmission 10 includes a first transmission unit 14 mainly composed of a double pinion type first planetary gear unit 12, a single pinion type second planetary gear unit 16, and a double pinion type third planetary gear unit. The second transmission unit 20, which is mainly composed of 18, is provided on a coaxial line, and the rotation of the input shaft 22 is shifted and output from the output shaft 24. The input shaft 22 corresponds to an input member. In this embodiment, the input shaft 22 is a turbine shaft of a torque converter 32 that is rotationally driven by an engine 30 that is a driving power source, and the output shaft 24 corresponds to an output member. The left and right drive wheels are rotationally driven via a propeller shaft and a differential gear device. The engine 30 is an internal combustion engine that generates power by burning fuel, and the torque converter 32 corresponds to a fluid power transmission device. The automatic transmission 10 and the torque converter 32 are substantially symmetrical with respect to the center line, and the lower half of the center line is omitted in FIG.

  FIG. 2 represents the rotational speeds of the rotating elements (sun gears S1 to S3, carriers CA1 to CA3, ring gears R1 to R3) of the first transmission unit 14 and the second transmission unit 20 of the automatic transmission 10 in a straight line. In the collinear chart, the lower horizontal line is the rotational speed “0”, the upper horizontal line is the rotational speed “1.0”, that is, the same rotational speed as the input shaft 22, and the clutches C1 to C4 and the brakes B1 and B2 are operated. According to the state (engaged, released), the eight forward gear stages from the first speed forward gear stage “1st” to the eighth speed forward gear stage “8th” are established, and the first reverse gear stage “Rev1” and Two reverse gear stages of the second reverse gear stage “Rev2” are established. (B) in FIG. 1 is an operation table that collectively shows the relationship between the gears and the operation states of the clutches C1 to C4 and the brakes B1 and B2, where “◯” indicates engagement and “(○)” indicates engine. Engagement is shown only during braking. Since the brake B2 that establishes the first forward gear stage “1st” is provided with the one-way clutch F1 in parallel, it is not always necessary to engage the brake B2 when starting (acceleration). Further, the gear ratios of the respective gear stages are the gear ratios of the first planetary gear device 12, the second planetary gear device 16, and the third planetary gear device 18 (= number of teeth of the sun gear / number of teeth of the ring gear) ρ1, ρ2. , Ρ3, and the gear ratio shown in FIG. 1 (b) is for ρ1 = 0.463, ρ2 = 0.594, and ρ3 = 0.405. Reference numeral 26 in FIG. 1 (a) denotes a transmission case.

FIG. 3 is a block diagram for explaining an outline of a control system provided in the vehicle for controlling the automatic transmission 10 and the engine 30. The accelerator operation amount sensor 52 detects the operation amount Acc of the accelerator pedal 50. It has come to be. The accelerator pedal 50 is largely depressed according to the driver's requested output amount, and corresponds to an accelerator operation member, and the accelerator operation amount Acc corresponds to the requested output amount. The intake pipe of the engine 30 is provided with an electronic throttle valve 56 that has an opening angle (opening) θ _TH corresponding to the accelerator operation amount Acc by a throttle actuator 54. Further, the engine speed sensor 58 for detecting the rotational speed NE of the engine 30, the fully closed state (idle state) of the electronic throttle valve 56, and the throttle valve opening with an idle switch for detecting the opening degree θ _TH thereof. Sensor 60, engine coolant temperature sensor 62 for detecting coolant temperature Tw of engine 30, vehicle speed sensor 64 for detecting vehicle speed V (corresponding to rotation speed Nout of output shaft 24), turbine rotation speed NT (= input) A turbine rotation speed sensor 66 for detecting the rotation speed Nin) of the shaft 22, a brake switch 68 for detecting the operation of a foot brake as a service brake, and a lever position (operation position) P _SH of the shift lever 72. Lever position sensor 74 for detection, air conditioner 76, M mode switch 78, upshift A switch 80, a downshift switch 82, and the like are provided. The engine rotational speed NE, the throttle valve opening _θTH , the engine cooling water temperature Tw, the vehicle speed V, the turbine rotational speed NT, the presence / absence of brake operation, the lever position of the shift lever 72 Signals indicating P _SH , the operating state (required load) of the air conditioner 76, whether or not the M mode (manual shift mode) can be manually switched can be selected, and an up command SUP, a down command SDN, etc. 90.

  The electronic control unit 90 includes a so-called microcomputer having a CPU, a RAM, a ROM, an input / output interface, and the like. The CPU uses a temporary storage function of the RAM, and signals according to a program stored in the ROM in advance. By performing the processing, the output control of the engine 30 and the shift control of the automatic transmission 10 are executed, and the engine control and the shift control are divided as necessary.

The output control of the engine 30 by the electronic control unit 90 includes opening / closing control of the electronic throttle valve 56 by the throttle actuator 54, control of the fuel injection unit 92 for fuel injection amount control, and igniter for ignition timing control, etc. The ignition device 94 is controlled. Control of the electronic throttle valve 56, for example, drives the throttle actuator 54 based on the actual accelerator operation amount Acc, an accelerator operation amount Acc increases the throttle valve opening theta _TH enough to increase. Further, when the engine 30 is started, the crankshaft of the engine 30 is cranked by a starter (electric motor) 96.

Shift control of the automatic transmission 10 is performed in accordance with the lever position P _SH of the shift lever 72. The shift lever 72 is disposed in the vicinity of the driver's seat (center console portion), and “P (parking)”, “R (reverse)”, “N (neutral)”, “D (drive) according to the shift pattern shown in FIG. ) ”And“ M (manual) ”are selectively operated to the lever positions P _SH , and the lever positions“ P ”,“ R ”,“ N ”, and“ D ”are detected by the lever position sensor 74. The lever position “M” is detected by the M mode switch 78. Before and after the lever position “M”, a “+” position and a “−” position are provided.

  The lever position “P” is a parking position, the automatic transmission 10 is in a power transmission cut-off state, and the output shaft 24, that is, the driving wheel is mechanically rotated by a parking lock mechanism or the like according to the movement operation of the shift lever 72, for example. Fixed to impossible. The lever position “R” is a reverse travel position for performing reverse travel. For example, when the manual valve of the hydraulic control circuit 98 (see FIG. 3) is mechanically switched in accordance with the movement operation of the shift lever 72, the automatic transmission 10 is The reverse gear stage “Rev1” or “Rev2” is established. The lever position “N” is a power transmission cut-off position. For example, when the manual valve is mechanically switched in accordance with the movement operation of the shift lever 72, the automatic transmission 10 is configured to include all or part of the clutches C1 to C4 and the brakes B1 and B2. Is released and the power transmission is cut off.

  The lever position “D” is a forward travel position in which the forward gear of the automatic transmission 10 is automatically switched and travels forward, that is, a forward travel position. For example, the manual valve is mechanically switched according to the movement operation of the shift lever 72. Thus, it is possible to establish all the forward gear stages “1st” to “8th”, and the highest gear that automatically shifts using all the forward gear stages “1st” to “8th”. The D range (automatic shift mode) is established. That is, when the shift lever 72 is operated to the lever position “D”, this is judged from the signal of the lever position sensor 74 to electrically establish the D range, and the first forward gear stage “1st” to the first Shift control is performed using all the forward gears of the eighth forward gear “8th”. More specifically, the hydraulic circuit is switched by controlling the excitation and de-excitation of a plurality of sonolide valves provided in the hydraulic control circuit 98 and the AT solenoid 99 of the linear solenoid valve, and the clutch as shown in FIG. By changing the operating states of C1 to C4 and the brakes B1 and B2, any one of the first forward gear stage “1st” to the eighth forward gear stage “8th” is established. For example, as shown in FIG. 6, the shift control is performed according to a shift condition such as a shift map stored in advance using the vehicle speed V and the accelerator operation amount Acc as parameters, and the vehicle speed V decreases or the accelerator operation amount Acc increases. As a result, the forward gear on the low speed side having a large gear ratio is established.

  The lever position “M” is an M (manual) position, and a manual shift mode (M mode) in which a plurality of predetermined shift ranges are electrically switched in accordance with a manual operation is established. That is, the “+” position and the “−” position provided before and after the “M” position are the upshift position and the downshift position, respectively, and the shift lever 72 is operated to the “+” position or “−” position. Then, this is detected by the upshift switch 80 and the downshift switch 82, and the shift range is switched. FIG. 7 is a diagram showing a predetermined shift range and its shift range. The numbers “1” to “8” in the gear stage column are the first speed forward gear stage “1st” to the eighth speed forward gear stage “ 8th ", the lowest speed forward gear stage having the largest speed ratio is the first speed forward gear stage" 1st ", and the highest speed forward gear stage is changed one by one. Further, in each shift range, a shift is automatically performed in the range from the first forward gear stage “1st” to the highest speed forward gear stage according to the same shift conditions of FIG.

  The “+” position and the “−” position are both unstable, and the shift lever 72 is automatically returned to the lever position “M” by a biasing means such as a spring. The upshift switch 80 and the downshift switch 82 are both automatic return type manual shift switches that are turned on by the driver through the shift lever 72, and automatically return to the OFF state by a biasing means such as a spring. To do. The M mode switch 78 is maintained in the ON state even when the shift lever 72 is operated to the “+” position or the “−” position, and the M mode is continued.

  The electronic control unit 90 also functionally includes a creep torque control means 110 shown in FIG. The creep torque control means 110 controls the driving force, that is, the creep torque when the accelerator operation amount Acc is 0 and the accelerator is OFF. The creep torque control means 110 includes an idle rotation speed control means 112 and an idle gear stage setting means 114. Signal processing is performed according to the flowchart shown in FIG. Steps S3 to S5, S7, S9, S10, S11, S12, S14, S16, and S17 in the flowchart of FIG. 8 are executed by the idle rotation speed control means 112, and steps S6, S8, S13, and S15 are the gear settings during idling. Performed by means 114.

  In step S1 of FIG. 8, based on the signal supplied from the lever position sensor 74, whether or not the shift lever 72 has been selected and operated to the travel position, that is, any one of “R”, “D”, and “M”. It is determined whether or not the vehicle is operated to the current position. If the vehicle is operated to the travel position, step S2 is executed. In step S2, it is determined whether or not the vehicle speed V is in a stopped state, or whether or not the vehicle is in a creep running state where the accelerator speed is OFF (Acc = 0) and the vehicle speed V is a predetermined value (for example, about 5 to 10 km / h) If it is neither the vehicle stop state nor the creep running state, step S18 is executed, but if it is the vehicle stop to creep running state, step S3 and subsequent steps are executed. In step S3, it is determined whether or not the forward movement position “D” or “M” is operated when the shift lever 72 is in a forward start. If the forward start is in progress, step S4 and subsequent steps are executed. That is, when the shift lever 72 is operated to the reverse travel position “R” and the vehicle starts moving backward, step S11 and subsequent steps are executed.

  In step S4, which is executed when the vehicle starts moving forward, it is determined whether or not the idle-up flag F1 during forward movement is “1”. The initial value of the idle-up flag F1 is “0”, and step S5 is executed first. It is determined whether or not a predetermined idle up condition is satisfied. The idle-up condition is, for example, when the engine cooling water temperature Tw is equal to or lower than a predetermined value and a warm-up operation is required, or when the air conditioner 76 is highly loaded and the compressor rotation speed, that is, the engine rotation speed NE needs to be increased. If the idle up condition is satisfied, step S8 and subsequent steps are executed. If the idle up condition is not satisfied, step S6 and subsequent steps are executed.

In step S6, the gear stage of the automatic transmission 10 is set to the first speed forward gear stage “1st”, the vehicle is started at the first speed forward gear stage “1st”, and in step S7, the idle rotation speed of the engine 30 is started. NE _idle is set to a normal value, that is, a predetermined low-speed idle rotational speed NE1, and the electronic throttle valve 56, the fuel injection device 92, and the like are set so that the actual engine rotational speed NE becomes the low-speed idle rotational speed NE1. Feedback control. The first speed forward gear stage “1st” corresponds to a low speed gear stage during normal idling. Further, the low idle rotation speed NE1 is set to a value as low as possible within a range that does not cause engine stall or unstable operation of the engine 30 in order to improve fuel efficiency.

In step S8, which is executed when the determination in step S5 is YES (affirmed), that is, when the idle-up condition is satisfied, the gear stage of the automatic transmission 10 is set to a predetermined high-speed high gear stage. While starting the vehicle, in step S9, the _idle speed NE _idle of the engine 30 is set to a predetermined high speed idle speed NE2, and the electronic engine speed NE is set to the high speed idle speed NE2. The throttle valve 56 and the fuel injection device 92 are feedback-controlled. The high-speed idle rotational speed NE2 is such that the vehicle driving force (corresponding to the creep torque) obtained when the gear stage of the automatic transmission 10 is set to the high gear stage is the first low-speed forward gear stage “1” at the low-speed idle rotational speed NE1. It is determined based on the torque characteristics of the torque converter 32 and the gear ratio of the automatic transmission 10 so as to be the same as the driving force at the time of normal idling of “1st”.

That is, as shown in the above equation (1), the driving force F of the vehicle is the output torque of the torque converter 32 that is rotationally driven by the engine 30, that is, the input torque Tin of the automatic transmission 10, and the gear ratio I of the automatic transmission 10. Since it is obtained by multiplying by a coefficient α determined by the final reduction ratio of the differential gear device, the tire diameter, etc., the input when the idling speed NE _idle of the engine 30 is set to the low idling speed NE1 during normal idling. When the torque is Tin1, the gear ratio of the first forward gear “1st” is I _1st , and the gear ratio of the high gear is I _HI , the high-speed idle so that the input torque Tin2 that satisfies the following equation (3) is obtained The rotational speed NE2 may be set. FIG. 9 shows an example of the output torque characteristics of the torque converter 32. In the case of the output rotational speed, that is, the turbine rotational speed NT = 0, in other words, when the vehicle is stopped, the idle rotational speed NE _idle is the input rotational speed (pump rotational speed). The input torque Tin corresponds to the output torque (turbine torque) of the torque converter 32. As is apparent from FIG. 9, the input torque Tin (the output torque of the torque converter 30) depends on the idle rotation speed NE _idle (pump rotation speed), and the input torque Tin increases as the idle rotation speed NE _idle increases. The engine speed NE2 at which the input torque Tin2 obtained according to the equation (3) is obtained based on this torque characteristic is set to a high idle speed.
Tin 2 × I _HI = Tin 1 × I _1st (3)

Further, the high-speed idle rotation speed NE2 needs to be higher than the _idle rotation speed NE _idle ^* required at the time of idle-up due to warm-up operation or a high load of the air conditioner 76. On the other hand, when the transmission gear ratio I _{1st of} the first speed forward gear stage “1st” and the transmission gear ratio I _HI of the high gear stage are close, the high-speed idle rotational speed NE2 is also close to the normal low-speed idle rotational speed NE1, and NE2 < NE _idle ^* may occur. In this case, the high-speed idle gear speed NE2 is increased by setting the high-speed forward gear stage having a smaller gear ratio as the high gear stage at the time of idle-up so that NE2 ≧ NE _idle ^*. You can do it. In this embodiment, as shown in FIG. 1B, the transmission gear ratio I _1st (≈4.596) of the first forward gear stage “1st” and the transmission gear ratio I _{2nd of} the second forward gear stage “2nd”. (≈2.724) is relatively far away, and even in the second speed forward gear stage “2nd”, the high-speed idle rotational speed NE2 that can obtain a driving force comparable to that during normal idling is the required idle rotational speed NE. _idle ^* becomes higher than, the second forward gear stage "2nd" is adapted to be set as high gear stage in step S8.

  In the next step S10, the idle-up flag F1 at the time of forward movement is set to “1”, so that in subsequent cycles, step S8 and subsequent steps are executed following the step S4, and the engine idles up due to an increase in the engine cooling water temperature Tw or the like. Even when the condition is not satisfied, the idle-up state of the high gear stage (second forward gear stage “2nd”) is maintained at the high idle speed NE.

  Further, when the determination in step S3 is NO (No), that is, steps S11 to S17 that are executed when the shift lever 72 is operated to the reverse travel position “R”, the steps S11 to S17 are basically the above steps S4 to S10. In step S11, it is determined whether or not the idle-up flag F2 during reverse travel is “1”. The initial value of the idle up flag F2 is “0”. At first, step S12 is executed, and it is determined whether or not a predetermined idle up condition is satisfied as in step S5. The idle-up condition at this time may be the same as that in step S5, but a different condition can be set. If the idle-up condition is satisfied, step S15 and subsequent steps are executed to satisfy the idle-up condition. If not, step S13 and subsequent steps are executed.

In step S13, the gear stage of the automatic transmission 10 is set to the first reverse gear stage “Rev1”, the vehicle is started at the first reverse gear stage “Rev1”, and in step S14, the _idle speed NE _{idle of the} engine 30 is started. Is set to a normal value, that is, the low-speed idle rotational speed NE1, and the electronic throttle valve 56 and the fuel injection device 92 are feedback-controlled so that the actual engine rotational speed NE becomes the low-speed idle rotational speed NE1.

In step S15, which is executed when the determination in step S12 is YES (affirmative), that is, when the idle-up condition is satisfied, the gear stage of the automatic transmission 10 is set to a predetermined high-speed gear, which is reverse in this embodiment. Since there are only two gear stages, the second reverse gear stage “Rev2” is set, and the vehicle is started at the second reverse gear stage “Rev2”. In step S16, the _idle speed NE _idle of the engine 30 is determined in advance. The electronic throttle valve 56 and the fuel injection device 92 are feedback-controlled so that the actual engine rotational speed NE becomes the high idle speed NE3. The high-speed idle rotational speed NE3 is such that the driving force of the vehicle obtained when the gear stage of the automatic transmission 10 is the second reverse gear stage “Rev2” is the first reverse gear stage “Rev1” at the low-speed idle rotational speed NE1. Is determined based on the torque characteristics of the torque converter 32 and the gear ratio of the automatic transmission 10 in the same manner as in the case of the high-speed idle rotation speed NE2 during forward travel. Yes.

  Since the speed ratio of the first speed forward gear stage “1st” and the speed ratio of the first reverse gear stage “Rev1” are different, if the low idle speed NE1 during normal idling is the same, Needless to say, the driving force (creep torque) is different from that when starting backward. However, the low-speed idle rotational speed NE1 can be made different so that their driving forces are the same.

  In the next step S17, the idle-up flag F2 for reverse traveling is set to “1”, so that in subsequent cycles, step S15 and subsequent steps are executed following the step S11, and the engine is idled due to an increase in the engine cooling water temperature Tw or the like. Even when the condition is no longer satisfied, the idle-up state of the second reverse gear stage “Rev2” is maintained at the high-speed idle rotation speed NE3.

  On the other hand, when the determination in step S2 is NO (negative), that is, in step S18 that is executed when the vehicle is neither in a stopped state nor in a creeping state, the gear stage of the automatic transmission 10 is set in step S8 or S15. It is determined whether or not the gear is other than the high gear, and if the high gear is maintained, the present control is terminated. However, if the gear is switched to a gear other than the high gear according to the shift map of FIG. The idle up flags F1 and F2 are both set to “0”. As a result, when the vehicle speed V decreases and step S3 and subsequent steps are executed again, it is determined whether or not the idle up condition is satisfied in step S5 or S12. Control during normal idling by NE1 is performed.

As described above, in the vehicle drive control apparatus of the present embodiment, when the idle-up condition is satisfied during warm-up operation or when the air conditioner 76 is heavily loaded (YES in step S5 or S12), step S8 is performed. Alternatively, in S15, a high gear stage with a small gear ratio is set, and in step S9 or S16, idle-up control is performed to increase the _idle rotation speed NE _idle of the engine 30, but the engine rotation speeds NE2, NE3 during the idle-up are performed. Is determined to generate a driving force (creep torque) of the same magnitude as that at the time of normal idling of the low speed gear stage at the low idle speed NE1. This prevents the driver from feeling uncomfortable.

  Further, when the engine 30 is operated at the high idle speed NE2 or NE3 and the idle up condition is not satisfied, when the engine 30 is switched to the normal idle state at the low gear speed at the low idle speed NE1, the final Even if the driving force is the same, it is inevitable that the driving force fluctuates transiently due to a change in the operating state of the engine 30 or a shift of the automatic transmission 10 to cause the driver to feel uncomfortable. In the example, since the idle up flags F1 and F2 are set to “1” in step S10 or S17, the idle up state of the high speed idle rotational speed NE2 and NE3 is maintained even if the idle up condition is not satisfied. As a result, fluctuations in the driving force are prevented and the driver does not feel uncomfortable.

  As mentioned above, although the Example of this invention was described in detail based on drawing, this is an embodiment to the last, and this invention implements in the aspect which added various change and improvement based on the knowledge of those skilled in the art. Can do.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a diagram for explaining an example of a vehicle drive device to which the present invention is preferably applied, in which FIG. It is a table. In the automatic transmission of FIG. 1, it is a collinear diagram which can connect the rotational speed of each member with a straight line. It is a block diagram explaining the principal part of the control system with which the vehicle drive device of FIG. 1 is provided. FIG. 4 is a functional block diagram relating to creep torque control performed by the electronic control device of FIG. 3. It is a figure which shows an example of the shift pattern of the shift lever of FIG. It is a figure which shows an example of the shift map which switches the gear stage of the automatic transmission of FIG. 1 automatically. It is a figure explaining the shift range of the automatic transmission of FIG. 1, and its shift range. 5 is a flowchart for specifically explaining the contents of driving force control performed during idling by the creep torque control means of FIG. 4. It is a figure explaining an example of the torque characteristic of the torque converter of FIG.

Explanation of symbols

  8: Vehicle drive device 10: Automatic transmission 30: Engine 32: Torque converter (fluid power transmission device) 90: Electronic control device 112: Idle rotation speed control means 114: Idle gear stage setting means NE1: Low speed idle rotation Speed NE2: High idle speed

Claims (2)

A vehicle drive device having an engine, a fluid power transmission device and an automatic transmission;
Idle rotation speed control means for switching the idle rotation speed of the engine to a predetermined high idle rotation speed when a predetermined idle up condition is satisfied;
When the idle rotational speed control means sets the high-speed idle rotational speed, the idle gear stage setting means for switching the gear stage of the automatic transmission to a high-speed gear stage as compared with the normal time when the idle rotational speed is low;
In a vehicle drive control device having
When the high-speed idle rotation speed is switched to the high-speed side gear stage, a driving force comparable to that during normal idling where the idle rotation speed is low and the low-speed gear stage is set can be obtained. A drive control apparatus for a vehicle characterized by being defined. The idle speed control means maintains the high idle speed even if the idle up condition is not satisfied while the engine is operating at the high idle speed. The vehicle drive control apparatus described.

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