JP2006017147A - Vehicle control device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To improve starting performance as well as durability of a starting clutch. <P>SOLUTION: A target engine speed Target-Ne is calculated based on a reference clutch transmission torque Base-Trq, a creep clutch torque rate K and a capacity coefficient τ (S11 to S14), and a present engine speed Ne is controlled so as to reach the target engine speed Target-Ne (S15 and S16). <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a vehicle control device having a starting clutch.

  Patent Document 1 discloses a starting clutch control device that calculates an index corresponding to a running resistance of a vehicle based on an actual engagement state of a starting clutch, sets a target clutch capacity according to the index, and sets the target clutch capacity. It is described that the engagement state of the starting clutch is adjusted so that the clutch capacity is obtained, and stable creep traveling is realized regardless of changes in traveling resistance due to a road surface inclination state or the like.

Further, Patent Document 2 discloses a vehicle creep control device, which appropriately sets a target creep speed and creep torque (creep clutch engagement) based on external conditions (road surface conditions, outside air temperature, engine water temperature, road gradient, weather information, etc.). (Torque) is set, while an amount for correcting the creep torque is calculated based on the target creep speed, and the final creep torque is calculated from the target creep torque and the creep torque correction amount. The creep torque correction amount is calculated according to changes in the driving environment (gradient and load increase). Then, the engine and the clutch engagement pressure are controlled based on the calculated creep torque.
JP 2000-186726 A JP 2003-262240 A

Here, in the device described in Patent Document 1, when creeping is limited, stable creeping is possible regardless of changes in running resistance, but starting or re-fastening when running resistance is changed (increased) It is not described, and in this case, there is a possibility that the running performance and the durability of the clutch are lowered.
Further, in the device described in Patent Document 2, since the creep torque increases as the running resistance increases, the switching point between the creep torque and the capacity control torque before the running resistance increases changes, and the clutch engagement time increases. There is a risk that the durability will deteriorate due to the deterioration of the starting performance. In addition, Patent Document 2 does not describe starting or re-engagement, and there is a possibility that running performance and clutch durability may be lowered.

  The present invention has been made in view of the above problems, and an object of the present invention is to improve running performance and clutch durability when starting a vehicle.

  Therefore, in the present invention, when the vehicle starts, the target engine speed is corrected based on the running resistance, and the engine speed is controlled so as to reach the corrected target engine speed.

  According to the present invention, when the vehicle starts, even if the running resistance at that time changes (even when the running resistance is large), the engine speed is controlled in accordance with this, so that the running performance and clutch durability are improved. There is an effect that can be.

Hereinafter, embodiments of the present invention will be described with reference to the drawings.
FIG. 1 is a system configuration diagram showing a vehicle control device 1 according to the present invention. FIG. 2 is a block diagram showing control by a transmission control unit (hereinafter referred to as “TCU”) 30 and an engine control unit (hereinafter referred to as “ECU”) 40.
The engine 2 is connected to an engine power transmission shaft 6 that transmits power from the engine 2 to the continuously variable transmission 5 via a damper 3 and a starting clutch 4 (wet multi-plate clutch).

  The continuously variable transmission 5 is provided in a primary pulley 7 and a secondary pulley 8, a belt 9 that is wound around these pulleys 7 and 8, and transmits the rotational force of the primary pulley 7 to the secondary pulley 8, and the pulleys 7 and 8, respectively. The hydraulic actuators 10a and 10b are configured. The hydraulic actuators 10a and 10b can control the gear ratio steplessly by changing the pulley ratio by hydraulic control.

An output shaft 11 that outputs power after the shift is connected to the secondary pulley 8 of the continuously variable transmission 5. The power from the output shaft 11 drives the tire 15 via the final gear 12, the differential 13 and the drive shaft 14.
Here, the vehicle control device 1 is provided with various sensors for detecting the operating state of the engine 2. For example, as shown in the figure, the engine 2 is provided with a crank angle sensor 16 that outputs a signal corresponding to the engine speed Ne. The primary pulley 7 of the continuously variable transmission 5 is provided with a primary pulley rotation speed sensor 17 that outputs a signal corresponding to the rotation speed Nt (turbine rotation speed). In addition, an accelerator opening sensor 18 that outputs a signal according to the accelerator opening APO, a gradient detection sensor 19 that outputs a signal according to the road surface gradient (%) in the longitudinal direction of the vehicle, and a signal according to the vehicle speed VSP. A vehicle speed sensor 20 for outputting, an ON / OFF type brake switch 21 for detecting depression of the brake pedal, and the like are disposed.

These output signals are input to the TCU 30 or the ECU 40, and various processes are performed.
As shown in the figure, the TCU 30 receives signals from the primary pulley rotation speed sensor 17 and the gradient detection sensor 19, and inputs the engine rotation speed Ne and the vehicle speed VSP from the ECU 40. Based on these inputs, the TCU 30 outputs the creep clutch torque ratio and the capacity coefficient to the ECU 40 and controls the clutch engagement pressure of the start clutch 4.

  The ECU 40 receives signals from the crank angle sensor 16, the accelerator opening sensor 18, and the vehicle speed sensor 20. Then, the creep clutch torque ratio and the capacity coefficient are input from the TCU 30 described above. The ECU 40 controls the opening degree of the electric throttle valve 25 in the engine intake system in order to perform various processes, particularly engine speed control, based on these inputs.

Next, control of the TCU 30 and the ECU 40 will be described with reference to FIG. Note that these controls are performed when the vehicle starts (including creep travel by re-engaging the clutch).
The TCU 30 includes a multiplier 31, a capacity coefficient calculator 32, a starting clutch torque calculator 33, a first creep clutch torque calculator 34, an engagement torque selector 35, a second creep clutch torque calculator 36, and a divider 37. ing.

Multiplying unit 31 calculates the square value Ne ² by multiplying the engine rotational speed Ne.
The capacity coefficient calculation unit 32 calculates the capacity coefficient τ of the starting clutch 4 from the speed ratio (Nt / Ne) calculated from the primary speed Nt and the engine speed Ne using a capacity coefficient calculation table. As shown in the figure, the capacity coefficient calculation table shows that the capacity coefficient τ is constant until the speed ratio reaches a predetermined value, and decreases when the speed ratio exceeds the predetermined value.

The starting clutch torque calculating unit 33 multiplies the square value Ne ² of the engine speed Ne calculated by the multiplying unit 31 by the capacity coefficient τ calculated by the capacity coefficient calculating unit 32 to thereby determine the starting clutch torque Tc (= τ × Ne ² ) is calculated. The starting clutch torque Tc is input to the engagement torque selection unit 35.
The first creep clutch torque calculation unit 34 refers to the creep clutch torque calculation table based on the road surface gradient resistance, which is the current running resistance, and the vehicle speed VSP, and calculates the current creep clutch torque GR-CrpTrq. The creep clutch torque calculation table indicates the torque required for creep travel depending on the degree of gradient, and therefore indicates that the creep clutch torque GR-CrpTrq increases as the gradient increases. The creep clutch torque GR-CrpTrq is input to the engagement torque selection unit 35.

The engagement torque selection unit 35 selects a larger torque from the start clutch torque Tc and the creep clutch torque GR-CrpTrq. As a result, the selected torque becomes the command clutch engagement torque (target clutch engagement torque). The TCU 30 controls the clutch engagement pressure of the start clutch 4 based on the command clutch engagement torque.
The second creep clutch torque calculation unit 36 performs the creep clutch according to the vehicle speed VSP when the vehicle starts in a state where there is no running resistance (here, the gradient resistance is 0%), that is, when the creep starts on a flat road. The creep clutch torque CrpTrq is calculated with reference to the torque calculation table.

The division unit 37 calculates the creep clutch torque ratio K (= GR-CrpTrq / CrpTrq) by dividing the creep clutch torque CrpTrq at a gradient of 0% from the current creep clutch torque GR-CrpTrq. The creep clutch torque ratio K is input to the ECU 40.
The ECU 40 includes a reference clutch transmission torque calculation unit 41, a multiplication unit 42, a division unit 43, a square root calculation unit 44, an engine speed feedback control unit (engine speed F / B control unit) 45, and a target engine torque selection unit 46. Has been.

The reference clutch transmission torque calculation unit 41 calculates a reference clutch transmission torque Base-Trq that serves as a reference for the clutch transmission torque using a reference clutch transmission torque calculation map according to the driving state, that is, the accelerator opening APO and the vehicle speed VSP.
The multiplier 42 multiplies the reference clutch transmission torque Base-Trq by the creep clutch torque ratio K (Base-Trq × K).

The division unit 43 divides the capacity coefficient τ from the value calculated by the multiplication unit 42 (Base-Trq × K / τ).
The square root calculation unit 44 calculates the square root of the values obtained by the reference clutch transmission torque calculation unit 41, the multiplication unit 42, and the division unit 43 ((Base-Trq × K / τ) ^ 0.5).
The value obtained by the reference clutch transmission torque calculating unit 41, the multiplying unit 42, the dividing unit 43, and the square root calculating unit 44 is the target engine speed Target-Ne (= (Base-Trq × K / τ) ^ 0.5). It becomes. The multiplication unit 42, the division unit 43, and the square root calculation unit 44 correspond to the target engine speed correction means, and thereby correct the target engine speed Target-Ne based on the running resistance. Thereby, the reference clutch transmission torque Base-Trq is corrected.

In general, the starting clutch torque (clutch engagement torque) Tc can be calculated by an expression (Tc = τ × Ne ² ) obtained by multiplying the capacity coefficient τ and the engine speed Ne, and when this expression is calculated for the engine speed Ne, Ne. = (Tc / τ) ^ 0.5. That is, the starting clutch torque Tc is a value obtained by the reference clutch transmission torque calculating unit 41 and the multiplying unit 42 (that is, Tc = Base-Trq × K).

The engine speed F / B control unit 45 performs PID control (correction) so that the current engine speed Ne becomes the target engine speed Target-Ne. Then, a target engine torque Target-Trq for maintaining the target engine speed Target-Ne is output.
The target engine torque selector 46 compares the target engine torque Target-Trq with the limit engine torque Limit-Trq and outputs the smaller torque as the final target engine torque. Note that a predetermined value is determined by the engine for the limit engine torque Limit-Trq.

The ECU 40 controls the opening degree of the electric throttle valve 25 according to the final target engine torque. Here, in order to cope with a change in driving force when the gradient resistance as the running resistance increases, the engine speed Ne is increased by increasing the opening of the electric throttle valve 25.
Next, the control at the time of vehicle start (including the creep travel by re-engaging the clutch) in the above configuration will be described with reference to FIG.

In step 1 (“S1” in the figure, the same applies hereinafter), the travel range is determined. If it is a traveling range, it will progress to Step 2. On the other hand, if it is outside the travel range, the process is not performed until the travel range is reached.
In step 2, the gradient is detected. A gradient detection sensor 19 is used to detect the gradient.
In step 3, the presence or absence of a brake operation is determined. This determination is made according to the ON / OFF state of the brake switch 21. If the brake is OFF, go to Step 4. On the other hand, if the brake is ON, the process returns to step 1.

In step 4, it is determined whether or not an accelerator operation has been performed. This determination is made based on the output signal of the accelerator opening sensor 18. If the accelerator is ON, go to step 5. In this way, it is determined whether or not the vehicle is starting (or creeping). On the other hand, if the accelerator is OFF, the process returns to step 1.
In step 5, the speed ratio is calculated by dividing the engine speed Ne from the primary speed Nt (speed ratio = Nt / Ne).

In step 6, the capacity coefficient τ of the starting clutch 4 is calculated from the speed ratio using the capacity coefficient calculation table. This process is performed by the capacity coefficient calculation unit 32.
In step 7, the creep clutch torque GR-CrpTrq based on the gradient is calculated. This process is performed by the first creep clutch torque calculator 34.
In step 8, the starting clutch torque Tc is calculated from the capacity coefficient τ and the square value of the engine speed Ne (Tc = τ × Ne ² ). This process is performed by the starting clutch torque calculator 33.

In step 9, a command clutch engagement torque is selected from the start clutch torque Tc and the creep clutch torque GR-CrpTrq. This process is performed by the fastening torque selection unit 35.
In step 10, the clutch engagement pressure is controlled according to the command clutch engagement torque. This is performed by the TCU 30 controlling the clutch engagement pressure.
In step 11, the creep clutch torque CrpTrq at a gradient of 0% (flat road surface) is calculated. This process is performed by the second creep clutch torque calculator 36.

In step 12, the creep clutch torque ratio K (= GR−CrpTrq / CrpTrq) is calculated from the creep clutch torque CrpTrq at a gradient of 0% and the current creep clutch torque (considering the gradient resistance). This process is performed by the division unit 37.
In step 13, the reference clutch transmission torque Base-Trq is calculated from the accelerator opening APO and the vehicle speed VSP. This process is performed by the reference clutch transmission torque calculation unit 41.

  In step 14, the target engine speed Target-Ne (= (Base-Trq × K / τ) ^ 0.5) is calculated from the reference clutch transmission torque Base-Trq, the creep clutch torque ratio K and the capacity coefficient τ. These processes are performed by the reference clutch transmission torque calculation unit 41, the multiplication unit 42, the division unit 43, and the square root calculation unit 44. With these processes, the target engine speed Target-Ne is corrected based on the gradient resistance.

In step 15, a target engine torque Target-Trq (or final target engine torque) is calculated such that the engine speed Ne becomes the target engine speed Target-Ne.
In step 16, the opening degree control (PID control) of the electric throttle valve 25 is performed to realize the target engine torque Target-Trq, and the engine speed Ne is controlled to reach the corrected target engine speed Target-Ne. To do.

  Next, when the engine speed Ne is controlled as described above, the command clutch engagement torque of the start clutch 4 (the larger of the start clutch torque Tc and the creep clutch torque GR-CrpTrq based on the running resistance) Will be described with reference to FIG. FIG. 4A is a diagram showing a case where the correction of the target engine speed Target-Ne is performed and a case where the correction is not performed. (B) is a diagram showing the clutch engagement torque of the starting clutch 4 when the target engine speed Target-Ne is corrected and when there is no correction.

First, a case where the target engine speed Target-Ne is not corrected (prior art) will be described. In this case, the engine speed Ne and the command clutch engagement torque of the start clutch 4 have the characteristics shown by the broken lines.
When starting from a state where the vehicle stops on a flat road, the command clutch torque needs to exceed the creep clutch torque CrpTrq at a gradient of 0% as shown in FIG. The time required for the command clutch torque to become the creep clutch torque CrpTrq is indicated by t1.

The command clutch engagement torque in this case is the creep clutch torque CrpTrq (predetermined value) at a gradient of 0% until time t1, and the starting clutch torque Tc (= τ × Ne ² ) after time t1.
Here, when starting uphill from a state where the vehicle is on a slope, that is, a state where the vehicle is stopped on a slope, a creep clutch torque GR-CrpTrq corresponding to the slope resistance is required. This is because it is necessary to ensure the creep force on the slope road. When the gradient is 0%, the time required for the creep clutch torque CrpTrq to reach GR-CrpTrq is indicated by t2. The time difference from t1 to t2 is indicated by Δt.

The command clutch engagement torque in this case is the creep clutch torque GR-CrpTrq (predetermined value) corresponding to the gradient resistance until time t2, and thereafter the starting clutch torque Tc (= τ × Ne ² ).
Therefore, there is no response during Δt compared to the flat road, and it is felt that the start response is lowered for the driver. In order to solve this problem and secure a start response that is similar to a flat road, it is necessary to start up the command clutch engagement torque of the start clutch 4 more quickly than the flat road.

Further, a case where the target engine speed Target-Ne is corrected when starting on a slope (the present invention) will be described. In this case, the engine speed Ne and the command clutch engagement torque of the start clutch 4 have the characteristics shown by the solid line.
As shown in FIG. 4B, when the target engine speed Target-Ne is corrected, the time required to reach the gradient road creep clutch torque GR-CrpTrq is indicated by t1. That is, the rise time of the torque at the start of the slope is shorter than the rise time of the torque at the start of the flat road, and the start response is improved.

The command clutch engagement torque in this case is the creep clutch torque GR-CrpTrq (predetermined value) corresponding to the gradient resistance until time t1, and thereafter the starting clutch torque Tc (= τ × Ne ² ).
Here, the gradient road creep clutch torque GR-CrpTrq can be calculated as the sum of the creep clutch torque CrpTrq and the gradient resistance Rs at a gradient of 0% (GR-CrpTrq = CrpTrq + Rs). The gradient resistance Rs can be expressed by the following equation: Rs = Wsin θ × r / ix × if, where the vehicle weight W, the inclination angle (gradient) θ, the tire dynamic radius r, the gear ratio ix, and the final gear ratio if. For this reason, even if the running resistance changes, the command clutch fastening torque can be increased in a short time, the heat generation and wear of the starting clutch 4 can be suppressed, and the durability of the clutch 4 can be improved.

Further, the starting clutch torque Tc (= τNe ² ) after time t1 can be expressed as K · Tc = K · τNe ² = GR-CrpTrq using K as the creep clutch torque ratio (creep clutch torque correction coefficient). Is possible. That is, as shown by the solid line of the starting clutch torque (command clutch engagement torque) Tc, the starting response can be improved by increasing the rising of the engine speed Ne.

In the above description, the gradient resistance is used as the running resistance. However, the present invention is not limited to this. For example, when the vehicle weight increases due to an increase in passengers, the engine speed Ne is similarly set to the target engine speed. It is good also as a structure controlled to several Target-Ne.
According to the present embodiment, in the vehicle control device having the start clutch 4, the target engine speed correction means (step 14) for correcting the target engine speed Target-Ne based on the running resistance when the vehicle starts, and the corrected Engine speed control means (steps 15 and 16) for controlling the engine speed Ne so as to reach the target engine speed Target-Ne. For this reason, even if the running resistance changes when the vehicle starts, the engine speed Ne can be controlled accordingly, and the running performance and clutch durability can be improved.

  Further, according to the present embodiment, the vehicle has the first creep clutch torque calculating means (34, step 7) for calculating the creep clutch torque GR-CrpTrq based on the running resistance when the vehicle starts, and the target engine speed correcting means is Then, the target engine speed Target-Ne is corrected based on the creep clutch torque GR-CrpTrq (step 14). Therefore, the target engine speed Target-Ne can be accurately controlled based on the creep clutch torque GR-CrpTrq.

  Further, according to the present embodiment, the second creep clutch torque calculating means (36, step 11) for calculating the creep clutch torque CrpTrq when there is no running resistance (gradient 0%) at the time of vehicle start, and the running resistance. Creep clutch torque ratio calculating means (37, step 12) for calculating the ratio K (= GR-CrpTrq / CrpTrq) between the creep clutch torque GR-CrpTrq calculated in the above and the creep clutch torque GR-CrpTrq in the absence of running resistance The target engine speed correction means corrects the target engine speed Target-Ne based on the creep clutch torque ratio K. Therefore, the target engine speed Target-Ne can be accurately controlled based on the creep clutch torque ratio K.

  Further, according to the present embodiment, the target engine speed correction means includes the clutch transmission torque (41, step 13) calculated based on the driving state (accelerator opening APO, vehicle speed VSP) and the capacity coefficient τ of the start clutch 4. Therefore, when calculating the target engine speed Target-Ne, the clutch transmission torque is corrected by the creep clutch torque ratio K (step 14). Therefore, the target engine speed Target-Ne can be accurately controlled by the creep clutch torque ratio K.

Further, according to the present embodiment, the reference clutch transmission torque Base-Trq that serves as a reference for the clutch transmission torque is calculated according to the accelerator opening APO and the vehicle speed VSP. For this reason, even if the accelerator opening APO and the vehicle speed VSP change, the reference clutch transmission torque Base-Trq corresponding to those changes can be calculated.
According to this embodiment, the running resistance is a gradient resistance. For this reason, it is possible to control the engine speed Ne so as to quickly rise when starting uphill, and it is possible to prevent the start response from being lowered.

The figure which shows a vehicle control apparatus Control block diagram Control flowchart Control timing chart

Explanation of symbols

  DESCRIPTION OF SYMBOLS 1 ... Vehicle control apparatus, 2 ... Engine, 4 ... Starting clutch, 5 ... Continuously variable transmission, 7 ... Primary pulley, 16 ... Crank angle sensor, 17 ... Primary pulley rotation speed sensor, 18 ... Accelerator opening sensor, 19 ... Gradient detection sensor, 20 ... vehicle speed sensor, 21 ... brake switch, 25 ... throttle valve, 30 ... TCU, 31 ... multiplication unit, 32 ... capacity coefficient calculation unit, 33 ... start clutch torque calculation unit, 34 ... first creep clutch torque Calculation unit, 35 ... engagement torque selection unit, 36 ... second creep clutch torque calculation unit, 37 ... division unit, 40 ... ECU, 41 ... reference clutch transmission torque calculation unit, 42 ... multiplication unit, 43 ... division unit, 44 ... Square root calculation unit, 45 ... target engine torque calculation unit, 46 ... target engine torque selection unit

Claims (6)

In a vehicle control device having a starting clutch,
Target engine speed correction means for correcting the target engine speed based on the running resistance when the vehicle starts,
Engine speed control means for controlling the engine speed so as to reach the corrected target engine speed;
A vehicle control device comprising: A first creep clutch torque calculating means for calculating a creep clutch torque based on the running resistance when the vehicle is started;
2. The vehicle control apparatus according to claim 1, wherein the target engine speed correcting means corrects the target engine speed based on the creep clutch torque. A second creep clutch torque calculating means for calculating a creep clutch torque when there is no running resistance when the vehicle starts,
Creep clutch torque ratio calculating means for calculating a ratio between a creep clutch torque calculated based on the running resistance and a creep clutch torque without the running resistance;
3. The vehicle control apparatus according to claim 2, wherein the target engine speed correction means corrects the target engine speed based on the creep clutch torque ratio.   The target engine speed correction means calculates the clutch transmission torque from the clutch transmission torque calculated based on the operating state and the capacity coefficient of the starting clutch, when the target engine speed is calculated. The vehicle control device according to claim 3, wherein the vehicle control device corrects by a ratio.   5. The vehicle control device according to claim 4, wherein a reference clutch transmission torque serving as a reference for the clutch transmission torque is calculated according to an accelerator opening and a vehicle speed.   6. The vehicle control device according to claim 1, wherein the running resistance is a gradient resistance.

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