JP4107232B2 - Control device for vehicle power transmission device - Google Patents

Description

  The present invention relates to a control device for a vehicle power transmission device including a continuously variable transmission as a transmission, and more particularly, to a driving force generated by an excessively large shift speed during acceleration such as kickdown traveling. The present invention relates to a technology for maintaining good acceleration performance while preventing “missing”.

2. Description of the Related Art A vehicle power transmission device is known that includes an engine as a drive source and a continuously variable transmission coupled to the engine. In a continuously variable transmission, unlike a stepped transmission using gears, the gear ratio can be continuously changed, but a certain amount of time is required until the gear ratio after shifting is reached.
In a vehicular power transmission device including a continuously variable transmission, a downshift is performed in order to obtain a required driving force during acceleration that generates a large acceleration, such as during kickdown travel, and the gear ratio is increased. Here, in the case of having a continuously variable transmission, the increase value of the gear ratio per unit time (that is, the shift speed of the downshift) is too large, so that the input system inertial body including the engine piston, the crankshaft, and the like. In order to obtain a rapid acceleration, engine output is consumed, the driving force is lost, and the vehicle may be temporarily decelerated. For this reason, it is known that the shift speed of the downshift at the time of acceleration should be set in consideration of missing driving force.

With regard to shift control of a vehicle power transmission device, it is known that, during acceleration, the downshift speed is changed to a value smaller than the downshift speed at other times, and the speed ratio is gradually increased. (Patent Document 1).
JP 2001-132834 A (paragraph number 0003)

  However, the above-described shift control in which the downshift speed is simply changed to a small value during acceleration has the following problems. That is, the vehicle body driving force is mainly determined by the engine output (represented by the product of the engine torque and the engine speed) and the gear ratio. Since the engine speed is a parameter that is uniquely determined by the vehicle speed and the gear ratio at that time, the vehicle body driving force is substantially determined by the gear ratio and the engine torque. The former speed ratio is a parameter to be controlled on the transmission side, and the latter engine torque is a parameter to be controlled on the engine side. Here, if the shift speed is decreased by the above-described shift control and no measures are taken with respect to the engine torque, the time required to reach the final gear ratio for obtaining the required vehicle driving force is reached. In the meantime, the driving force of the vehicle body is insufficient, and the response to the accelerator operation is lowered.

  The present invention prevents a drop in driving force due to improved shift control during acceleration, and suppresses a decrease in responsiveness by providing a relationship between fuel injection control and shift control. With the goal.

The present invention provides a control device for a vehicle power transmission device that includes an engine and a continuously variable transmission coupled to the engine.
In the first embodiment, the required shift speed to the ultimate transmission ratio according to the target vehicle body driving force is calculated. At the time of acceleration when the gear ratio is changed to a value larger than the current value (hereinafter simply referred to as “acceleration”), if the calculated required shift speed is greater than a predetermined limit shift speed, the shift speed is set to the limit shift speed. The first fuel supply amount that is determined in correspondence with the accelerator operation amount as the fuel supply amount to the engine when the shift speed is limited based on the required shift speed and the limited shift speed. The second fuel supply amount having a larger value is set. In the first mode, the difference between the transmission ratio obtained when the required transmission speed is obtained and the actual transmission ratio based on the limited transmission speed is calculated, and the second fuel is corrected according to the calculated difference. The supply amount should be set.

In the second mode, the required shift speed to the ultimate transmission ratio according to the target vehicle body driving force is calculated. When accelerating, the gear ratio is changed according to a preset limit shift speed, and when the requested shift speed is greater than the limit shift speed according to the amount of deviation of the limit shift speed from the calculated requested shift speed, As the fuel supply amount, a fuel supply amount larger than the normal fuel supply amount determined corresponding to the accelerator operation amount is set.

  According to the present invention, at the time of acceleration, the shift speed is limited to the limit shift speed regardless of the required shift speed. Can be avoided. In addition, according to the present invention, when the speed change is limited, the fuel supply amount is set to a value larger than that determined in accordance with the accelerator operation amount, thereby increasing the fuel supply amount to the engine. The responsiveness can be ensured by increasing the engine torque.

Embodiments of the present invention will be described below with reference to the drawings.
FIG. 1 shows a configuration of a vehicle power transmission device (hereinafter simply referred to as “power transmission device”) 1 according to an embodiment of the present invention. In this embodiment, a belt-driven type is adopted as the continuously variable transmission.
A crankshaft 111 of the engine 11 is connected to an input-side pulley 122 a of a continuously variable transmission (hereinafter referred to as “CVT”) 12 via an electromagnetic clutch (hereinafter simply referred to as “clutch”) 121. In a state where is fastened, the power of the engine 11 is transmitted to the CVT 12. A metal belt 122c is stretched between the input pulley 122a and the output pulley 122b of the CVT 12, and power is transmitted from the input pulley 122a to the output pulley 122b by the belt 122c. Each of the pulleys 122a and 122b on the input side and the output side is provided with a hydraulic actuator (not shown) that changes the distance between the sheaves of each pulley. By adjusting the ratio (hereinafter referred to as “pulley ratio”) R of the contact portion radii R1, R2, the transmission ratio RATIO of the CVT 12 is configured to change. The output pulley 122b is connected to the propeller shaft 13 via the final gear 123, and the power of the engine 11 is transmitted to the drive wheels 16 via the CVT 12, the propeller shaft 13, the differential 14 and the wheel drive shaft 15. .

  The transmission ratio RATIO is controlled by a transmission control unit (hereinafter referred to as “ATCU”) 31 based on a shift command signal from an engine control unit (hereinafter referred to as “ECU”) 21. The ECU 21 outputs a shift command signal to the ATCU 31 and outputs an operation command signal for a fuel supply injector and a throttle valve provided in the engine 11.

  The ECU 21 includes a signal from the accelerator sensor 41 that detects the accelerator pedal depression amount (accelerator operation amount) APO, a signal from the air flow meter 42 that detects the intake air amount Qa, and a signal from the crank angle sensor 43 (this) The engine speed NE is calculated based on the engine speed NE.), A signal from the vehicle speed sensor 44 that detects the vehicle speed VSP, a signal from the temperature sensor 45 that detects the coolant temperature TW, and the like. The ECU 21 controls the operation of the injector and the throttle valve based on each input signal, controls the torque generated by the engine 11, calculates the ultimate transmission ratio tRATIO of the CVT 12, and outputs this to the shift command signal. To the ATCU 31.

  The ATCU 31 adjusts the pulley ratio R so that the rotational speed Ni of the input side pulley 122a becomes the target input speed tNi corresponding to the input speed ratio tRATIO and detects the current actual speed ratio RATIO. And this is output to ECU21. The ATCU 31 receives a signal from the rotational speed sensor 46 that detects the rotational speed Ni of the input side pulley 122a and a signal from the rotational speed sensor 47 that detects the rotational speed No of the output side pulley 122b. The ATCU 31 multiplies the input output rotation speed No by the ultimate transmission ratio tRATIO to calculate the target input rotation speed tNi, and divides the input input rotation speed Ni by the output rotation speed No to change the speed. The ratio RATIO (= Ni / No) is calculated. The ATCU 31 changes the input side rotational speed Ni at a constant speed toward the target input side rotational speed tNi. This speed is set corresponding to a limit shift speed RSPLMT described later.

Next, driving force control according to the present embodiment will be described with reference to the flowcharts shown in FIGS.
FIG. 2 is a flowchart of the shift control routine. This routine is executed by the ECU 21 every predetermined time. In this routine, the reaching speed ratio tRATIO is calculated, and the speed change speed (that is, the speed changing speed) toward the calculated reaching speed ratio tRATIO is set.

In S101, various driving states such as the accelerator pedal depression amount APO and the vehicle speed VSP are read. In the present embodiment, the accelerator pedal depression amount APO corresponds to the operation request parameter of the engine 11.
In S102, based on the input APO and VSP, the target output of the engine 11 (= engine torque TRQ × engine speed NE) tLE and the ultimate transmission ratio in accordance with the vehicle speed VSP to obtain the target vehicle driving force Calculate tRATIO.

In S103, the current actual engine output LE is detected. The engine output LE can be estimated from the product obtained by multiplying the fuel injection amount Qf and the engine speed NE, but may be detected directly by installing a torque sensor.
In S104, a required shift speed tRSP for the ultimate transmission ratio tRATIO is calculated. The required shift speed tRSP is calculated by subtracting the engine output LE from the target engine output tLE and searching the table shown in FIG. 3 using the absolute value of the difference (hereinafter referred to as “output difference absolute value”) DLTabs. The required shift speed tRSP is calculated as a larger value as the output difference absolute value DLTabs is larger.

In S105, it is determined whether or not the accelerator pedal depression amount APO is equal to or greater than a predetermined acceleration determination value SLacc. If it is equal to or greater than Slacc, the accelerator pedal is greatly depressed, and it is determined that the acceleration is accompanied by a downshift, such as during kickdown travel, and the process proceeds to S106.
In S106, the limit shift speed RSPLMT is read. The limit shift speed RSPLMT is determined and set in advance by an experiment or the like in consideration of loss of driving force accompanying a downshift so that the driving force does not become a predetermined value (for example, 0) or less. Set to a relatively small value. In the present embodiment, the limit shift speed RSPLMT is a fixed value and is stored in the ECU 21.

In S107, it is determined whether or not the required shift speed tRSP is equal to the read RSPLMT. If equal, the process proceeds to S108, and if different, the process proceeds to S109.
In S108, the flag Ftrs is set to 0. The flag Ftrs is read in a fuel injection control routine described later.
In S109, the speed change speed is set to the limit speed change speed RSPLMT. That is, when the required shift speed tRSP is greater than the limit shift speed RSPLMT, the shift speed is limited to the limit shift speed RSPLMT, and conversely, when the required shift speed tRSP is less than the limit shift speed RSPLMT, Increase to speed RSPLMT.

In S110, the flag Ftrs is set to 1.
When the required shift speed tRSP is equal to the limit shift speed RSPLMT (S107), the required shift speed tRSP is set as the shift speed.
FIG. 4 is a flowchart of a fuel injection control routine. This routine is executed by the ECU 21 every predetermined time. In this routine, the fuel injection amount Qf is set.

In S201, various operation states such as the accelerator pedal depression amount APO, the intake air amount Qa, the engine speed NE, and the coolant temperature TW are read.
In S202, it is determined whether or not the flag Ftrs is 1. When it is 1, the process proceeds to S203 because the shift speed is limited or increased to the limit shift speed RSPLMT, and when it is not 1, the process proceeds to S204.

In S203, the fuel-air ratio correction value Klamb is calculated. The calculation of the fuel-air ratio correction value Klamb is performed by subtracting the current actual speed ratio (according to the limit speed change speed RSPLMT) from the current speed ratio obtained when the required speed change speed tRSP is used. This is done by searching the table shown in FIG. 5 using DltRTO.
DltRTO = (pRATIO + ΣtRSP × Δt) − (pRATIO + ΣRSPLMT × Δt) (1)
In equation (1), the gear ratio before the shift is pRATIO, and the calculation cycle is Δt.

The fuel-air ratio correction value Klamb is a value larger than 1 when the gear ratio difference DltRTO is a positive value, and is larger than 0 and smaller than 1 when the gear ratio difference DltRTO is a negative value. It is calculated as a small value and increases in proportion to the gear ratio difference DltRTO, including the latter case.
Here, the fuel-air ratio correction value Klamb will be additionally described. The fuel-air ratio correction value Klamb is used to compensate for an excess or deficiency in the engine output LE caused by an increase or decrease in the engine torque TRQ due to the speed change being limited or increased during acceleration. The engine output LE can be expressed as a product of the engine torque TRQ and the engine speed NE. For example, considering the case where the shift speed is limited, in this case, since the engine speed NE is set to a value smaller than that required by the required shift speed tRSP, the engine output LE is reduced accordingly, and the vehicle body driving force is reduced. Run short. The fuel-air ratio correction value Klamb in this case is set to a value larger than 1 as giving an engine torque TRQ that compensates for a decrease in the engine output LE due to a decrease in the engine speed NE. Conversely, considering the case where the transmission speed is increased, in this case, the engine speed NE becomes a larger value than in the case of the required transmission speed tRSP, and the engine output LE increases accordingly, so the fuel-air ratio correction value Klamb Is set to a value smaller than 1 so as to give an engine torque TRQ smaller than normal that offsets an increase in the engine output LE due to an increase in the engine speed NE.

In S204, the fuel-air ratio correction value Klamb is set to 1.
In S205, the target fuel-air ratio LAMB is calculated. The target fuel / air ratio LAMB is calculated by multiplying the fuel / air ratio correction value Klamb by a predetermined target fuel / air ratio LAMB according to the operating state of the engine 11.
LAMB = LAMB × Klamb (2)
In S206, the fuel injection amount Qf is calculated. The calculation of the fuel injection amount Qf is performed by multiplying the intake air amount Qa by the target fuel-air ratio LAMB. In the present embodiment, the target engine torque tTRQ corresponding to the accelerator pedal depression amount APO is set, and the intake air amount Qa and the fuel injection amount Qf are controlled based on the set target engine torque tTRQ. . That is, the target intake air amount tQa necessary for realizing the target engine torque tTRQ is set, and the opening degree of the throttle valve is controlled so as to obtain the set target intake air amount tQa. Based on the air amount Qa, a fuel injection amount Qf that supplies the target fuel-air ratio LAMB is supplied to the engine 11.

Qf = Qa × LAMB (3)
Note that the fuel injection amount set when the target fuel-air ratio is determined in advance corresponds to the “first fuel supply amount” or the “normal fuel supply amount”. Further, when the shift speed is limited, the fuel injection amount set by multiplying the fuel-air ratio correction value Klamb greater than 1 corresponds to the “second fuel supply amount”, and the shift speed is increased. In this case, the fuel injection amount set by multiplying the fuel-air ratio correction value Klamb smaller than 1 corresponds to the “third fuel supply amount”.

Next, the operation of the power control device 1 during acceleration will be described with reference to the time chart shown in FIG.
When the accelerator pedal is depressed (time t1), the target engine output tLE increases as the accelerator pedal depression amount APO increases. As the target engine output tLE increases, the speed change ratio tRATIO is switched from R1 to R2 larger than this, and the speed is changed at the limit speed change rate RSPLMT toward the reached speed change ratio tRATIO (= R2). . The ECU 21 detects the current actual engine output LE and calculates a required shift speed tRSP corresponding to the difference between the target engine output tLE and the engine output LE (that is, the output difference absolute value DLTabs). When the calculated required shift speed tRSP is greater than the limit shift speed RSPLMT, the shift speed is limited to the limit shift speed RSPLMT. When the calculated required shift speed tRSP is less than the limit shift speed RSPLMT, the shift speed is Is increased to the limit shift speed RSPLMT. Here, considering the former case where the required shift speed tRSP is large and is limited to the limit shift speed RSPLMT, the ECU 21 determines that the engine torque LE is insufficient due to insufficient increase in the engine speed NE. Therefore, a fuel / air ratio correction value Klamb greater than 1 corresponding to the gear ratio difference DltRTO is calculated and multiplied by the target fuel / air ratio LAMB to increase the fuel injection amount Qf and the engine torque TRQ. Increase. When the engine output LE approaches the target engine output tLE and the difference between them becomes smaller, the required shift speed tRSP decreases accordingly. When the transmission gear ratio RATIO reaches the ultimate transmission gear ratio tRATIO and the transmission gear ratio difference DltRTO decreases, the fuel-air ratio correction value Klamb decreases accordingly. The fuel-air ratio correction value Klamb becomes 1 when the speed ratio RATIO reaches the ultimate speed ratio tRATIO.

  In FIG. 6, the transmission gear ratio RATIO, the engine torque TRQ, and the acceleration ACC indicated by dotted lines are those that are not based on the driving force control according to the present embodiment. Regarding the transmission ratio RATIO, a dotted line indicates a case where the shift speed is higher than the limit shift speed RSPLMT, and a two-dot chain line indicates a case where the shift speed is lower than the limit shift speed RSPLMT.

  With respect to the present embodiment, S102 and 104 shown in the flowchart of FIG. 2 are required shift speed calculation means, S107 and 109 shown in the flowchart are shift speed limiting means and shift speed increasing means (or speed ratio control means), and FIG. S202 to 206 in the flowchart shown in FIG. Further, S103 in the flowchart shown in FIG. 2 constitutes an engine output detecting means.

According to this embodiment, the following effects can be obtained.
In the present embodiment, at the time of acceleration such as kick-down traveling, the speed change speed is set to the limit speed change speed RSPLMT regardless of the required speed change speed tRSP. The limit shift speed RSPLMT is set from the viewpoint of preventing the driving force from being lost due to a downshift accompanying acceleration. When the required shift speed tRSP is larger than the limit shift speed RSPLMT, the shift speed is set to By limiting to the limit shift speed RSPLMT, it is possible to avoid deceleration due to loss of driving force during acceleration. At the same time, when the limit shift speed RSPLMT is used, the target fuel-air ratio LAMB is increased and the engine torque TRQ is increased. Sex can be secured.

  On the other hand, when the requested shift speed tRSP is smaller than the limit shift speed RSPLMT, the engine speed TRQ is decreased by increasing the engine speed NE by increasing the engine speed NE by increasing the shift speed to the limit shift speed RSPLMT. It becomes possible to make it. For this reason, the target fuel-air ratio LAMB can be reduced, the fuel injection amount Qf can be reduced, and the fuel consumption can be reduced.

  In the above description, the speed change rate is the speed change rate of the speed ratio RATIO for each time, and the speed change ratio is changed by the constant limit speed change rate RSPLMT. However, according to the present invention, the value of the limit shift speed RSPLMT may be switched during acceleration, and the shift speed may be changed during the shift process. In addition, when the transmission speed is defined by a time constant and the transmission speed is limited, the transmission ratio is changed by a larger time constant toward the ultimate transmission ratio (if the transmission speed is increased, a smaller time constant is used). Thus, it is possible to substantially change the shift speed.

  In the above description, the continuously variable transmission has been described by way of example using a belt-driven CVT that transmits power by a belt. However, the present invention is a traction that transmits power by using friction between rolling elements. It can also be employed in a drive CVT.

Configuration of a vehicle power transmission device according to an embodiment of the present invention Shift control routine flowchart Required shift speed setting table Flow chart of fuel injection control routine Fuel / air ratio correction value setting table Concept of driving force control during acceleration

Explanation of symbols

  DESCRIPTION OF SYMBOLS 1 ... Power transmission device, 11 ... Engine, 12 ... Continuously variable transmission, 121 ... Electromagnetic powder clutch, 122a ... Input side pulley, 122b ... Output side pulley, 122c ... Belt, 123 ... Final gear, 13 ... Propeller shaft, 14 ... Differential, 15 ... Wheel drive shaft, 16 ... Drive wheel, 21 ... Engine control unit, 31 ... Transmission control unit, 41 ... Accelerator sensor, 42 ... Air flow meter, 43 ... Crank angle sensor, 44 ... Vehicle speed sensor, 45 ... Cooling water temperature sensor, 46... Input side rotational speed sensor, 47... Output side rotational speed sensor.

Claims (9)

Provided in a vehicle power transmission device including an engine and a continuously variable transmission coupled to the engine,
A required shift speed calculating means for calculating a required shift speed to an ultimate transmission ratio according to a target vehicle body driving force;
A shift that limits the shift speed to the limit shift speed when the request shift speed calculated by the request shift speed calculation means is greater than a predetermined limit shift speed during acceleration when the gear ratio is changed to a larger value than the present. Speed limiting means;
When the shift speed is limited by the shift speed limiting means based on the calculated requested shift speed and the shift speed after the shift speed limiting means is limited , the fuel operation amount corresponds to the accelerator operation amount. And a fuel supply amount setting means for setting a second fuel supply amount that is larger than the first fuel supply amount determined as described above. The fuel supply quantity setting means, the gear ratio obtained when according to the required speed rate and the calculated actual calculates a difference between the speed ratio by the shift speed after the limit, correcting the corresponding to the calculated difference The control device for a vehicle power transmission device according to claim 1, wherein the second fuel supply amount is set. During acceleration gear ratio is changed to a value greater than the current, when required gear speed that is the calculated is smaller than the limit shift speed, further includes a shift speed increase means for increasing than the shift speed required gear speed Configured,
The fuel supply quantity setting means, based on the shift speed after increase by the required gear speed and the shift speed increasing means and the calculated, the third fuel supply amount of a value different from the first fuel supply amount The control device for a vehicle power transmission device according to claim 1 or 2 to be set. The fuel supply quantity setting means, the gear ratio obtained when according to the required speed rate that is the setting, and calculates the difference between the actual speed ratio by the shift speed after the increase, correction was in accordance with the calculated difference The control device for a vehicle power transmission device according to claim 3 , wherein a third fuel supply amount is set. The control device for a vehicle power transmission device according to claim 3 or 4 , wherein the third fuel supply amount is smaller than the first fuel supply amount. The required gear speed calculating means, based on the operation request parameters for the engine, calculates the engine output to the target, based on the target engine output calculated, any claim 1-5 for calculating the required gear speed A control device for a vehicle power transmission device according to claim 1. It further comprises engine output detection means for detecting the actual engine output,
The required gear speed calculating means, a target engine output, and calculates the difference between the engine output detected by said engine output detection means, based on the calculated difference, according to claim 6 which calculates the required gear speed Control device for vehicle power transmission device. In setting a target intake air amount and supplying an amount of fuel that gives a predetermined target fuel-air ratio to the engine based on the set target intake air amount,
Further comprising intake air amount detection means for detecting the actual intake air amount;
The fuel supply quantity setting means, at steady state, while calculating a first fuel supply amount by multiplying the target air-fuel ratio in the intake air amount detected by the intake air amount detecting means, at the time of acceleration, the detection A second fuel supply amount is set by multiplying a target fuel / air ratio by the intake air amount and changing the target fuel / air ratio according to the calculated required shift speed and the limited shift speed. control device for a vehicular power transmitting device according to any one of 1-7. Provided in a vehicle power transmission device including an engine and a continuously variable transmission coupled to the engine,
A required shift speed calculating means for calculating a required shift speed to an ultimate transmission ratio according to a target vehicle body driving force;
A gear ratio control means for changing the gear ratio at a preset limit gear speed at the time of acceleration when the gear ratio is changed to a value larger than the present;
In accordance with the amount of deviation of the limit shift speed from the required shift speed calculated by the required shift speed calculating means, when the calculated required shift speed is larger than the limit shift speed , the amount of fuel supplied to the engine is And a fuel supply amount setting means for setting a fuel supply amount that is larger than a normal fuel supply amount that is determined in accordance with the operation amount.

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