JP2626032B2 - Control system for vehicle drive train - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Application Field] The present invention relates to control of a vehicle drive system including a continuously variable transmission capable of continuously adjusting a reduction ratio in a power transmission system from an internal combustion engine to drive wheels. More particularly, the present invention relates to a vehicle drive system control device that optimally controls a reduction ratio of a continuously variable transmission and an output torque of an internal combustion engine.

2. Description of the Related Art Conventionally, a vehicle provided with a continuously variable transmission capable of continuously adjusting a reduction ratio in a drive transmission system from an internal combustion engine to drive wheels, as described in, for example, Japanese Patent Application Laid-Open No. 62-110536. A target driving torque of the vehicle is set based on the accelerator operation amount (accelerator opening) of the vehicle driver and the vehicle speed, and a target input rotation speed of the continuously variable transmission is set based on the set target driving torque. 2. Description of the Related Art A control device of a vehicle drive system that determines a throttle opening and controls a reduction ratio of a continuously variable transmission and an output torque of an internal combustion engine is known.

This type of device has been developed for the purpose of enabling the vehicle to be driven with the driving torque required by the vehicle driver and with optimum fuel efficiency, and as described above, the continuously variable transmission based on the target driving torque. By controlling the speed reduction ratio of the internal combustion engine and the output torque of the internal combustion engine, the vehicle can be optimally driven.

[Problems to be Solved by the Invention] However, in the above-described device, since the driving torque of the vehicle as the control target is set based on the accelerator opening and the vehicle speed, the vehicle speed is controlled to the target vehicle speed required by the vehicle driver. I couldn't do that. That is, in the above device, the target drive torque is set based on the accelerator opening and the vehicle speed, assuming that the accelerator opening is the acceleration required by the vehicle driver. Although the vehicle can be accelerated or decelerated, it cannot be applied to a so-called target vehicle speed tracking system that controls the vehicle speed to a target vehicle speed required by the vehicle driver, and the control of the vehicle speed is left to the accelerator operation by the vehicle driver. There was only.

Further, in the above-described device, since the torque control of the internal combustion engine is performed without considering the shift transition of the continuously variable transmission, the vehicle can be accelerated and decelerated satisfactorily for a gentle accelerator operation. When the accelerator is operated, the output torque of the internal combustion engine is suddenly changed, and as a result, the continuously variable transmission is also rapidly shifted, causing a large shift shock.

In view of the above, the present invention provides a vehicle equipped with a continuously variable transmission as described above, which achieves a target vehicle speed required by a vehicle driver with optimum fuel efficiency and without a shift shock even when a sudden accelerator operation is performed. The purpose was to be able to control.

[Means for Solving the Problems] That is, the configuration of the present invention made to achieve the above object uses an internal combustion engine E / G as a drive source and has no reduction ratio in a power transmission system, as illustrated in FIG. This is a control device for a vehicle drive system equipped with a continuously variable transmission T / M that can be adjusted in stages.The optimum fuel efficiency characteristic that describes the relationship between the engine torque and the reduction ratio that minimizes fuel consumption when the vehicle is running is stored in advance. Means for storing the optimum fuel efficiency characteristics M1, a target vehicle speed setting means M2 for setting a target vehicle speed of the vehicle based on the accelerator operation amount by the vehicle driver, at least a reduction ratio of the continuously variable transmission T / M and a A traveling state detecting means M3 for detecting a traveling state of the vehicle including the vehicle speed; a vehicle having a vehicle speed as a state variable based on a detection result of the traveling state detecting means M3 and the target vehicle speed set by the target vehicle speed setting means M2. Describe the behavior of the drive system using the following equation. Using an arithmetic expression set based on the calculated physical model, a torque-torque calculating a torque-reduction ratio characteristic representing a relationship between an engine torque and a reduction ratio optimal for controlling the vehicle speed to the target vehicle speed.
Reduction ratio characteristic calculating means M4, I {R10T}. (DV / dt) = TE-TC (FR, R10T, V) R10T is the total reduction ratio of the power transmission system including the reduction ratio of the continuously variable transmission, V is vehicle speed, TE is engine torque, FR is running resistance, M is vehicle weight, r is tire radius, and IT is power transmission. The moment of inertia of the system, IE, represents the moment of inertia of the rotating part of the internal combustion engine.

Control amount calculating means M5 for calculating a target engine torque and a target reduction ratio for controlling the vehicle speed to the target vehicle speed with minimum fuel consumption based on the calculated torque-reduction ratio characteristics and the optimum fuel consumption characteristics; Control means M6 for feedback controlling the torque of the internal combustion engine E / G and the reduction ratio of the continuously variable transmission T / M according to the target engine torque and the target reduction ratio calculated by the calculation means M5. The gist of the invention is a control device for a vehicle drive system.

[Operation] In the control device for a vehicle drive system of the present invention configured as described above, first, the target vehicle speed setting means M2 sets the target vehicle speed based on the accelerator operation amount by the vehicle driver, and sets the torque-reduction ratio characteristic. The calculating means M4 sets the vehicle speed to the target vehicle speed based on the vehicle speed of the vehicle and the reduction ratio of the continuously variable transmission T / M detected by the traveling state detecting means M3 and the target vehicle speed set by the target vehicle speed setting means M2. The most suitable torque-reduction ratio characteristic for control is calculated. Then, the control amount calculation means M5 sets a target engine torque and a target reduction ratio based on the calculated torque-reduction ratio characteristic and the optimum fuel efficiency characteristic stored in the optimum fuel efficiency characteristic storage means M1, and the control means M6 Performs feedback control of the reduction ratio of the continuously variable transmission T / M and the torque of the internal combustion engine E / G based on the set target values.

That is, in the present invention, the vehicle speed is set as a state variable, and the behavior of the vehicle drive system is controlled based on the physical model described in the above equation. -Determine the reduction ratio characteristics and calculate the target engine torque and the target reduction ratio based on the torque-reduction ratio characteristics and the preset optimal fuel consumption characteristics, so that the vehicle speed can be optimized with optimum fuel efficiency and optimal transmission characteristics. The reduction ratio of the continuously variable transmission T / M and the torque of the internal combustion engine E / G are controlled so that the target vehicle speed can be controlled.

Embodiment An embodiment of the present invention will be described below with reference to the drawings.

FIG. 2 is a schematic configuration diagram showing the configuration of the entire control device for the vehicle drive system of the embodiment.

As shown in the figure, the vehicle of this embodiment uses an internal combustion engine 2 as a power source, and the rotation of the internal combustion engine 2 is controlled by a clutch mechanism 4, a belt-type continuously variable transmission (hereinafter referred to as CVT) 6, a differential gear (not shown), and the like. Is transmitted to the drive wheels via the motor.

Here, first, an intake pipe 8 of the internal combustion engine 2 is provided with an air cleaner 10 from an upstream thereof, a throttle valve 12 for controlling a flow rate (intake amount) of air flowing through the air cleaner 10,
A surge tank 14 for suppressing pulsation of intake air is provided.
The throttle valve 12 is configured to be able to adjust the opening through a throttle actuator 16, and is provided with a throttle opening sensor 18 for detecting the opening (throttle opening) θTH.

On the other hand, the CVT 6 includes an input pulley 24 and an output pulley 26 provided on the input shaft 20 and the output shaft 22, respectively, and a transmission belt 28 wound around the input / output pulleys 24 and 26. The input and output pulleys 24 and 26 are connected to the input shaft 20 respectively.
Alternatively, fixed pulleys 30 and 32 fixed to the output shaft 22 and the input shaft 2
0 or movable pulleys 34, 36 provided on the output shaft 22 so as to be movable in the axial direction and non-rotatable relative to the axis.The movable pulleys 34, 36 are moved in the axial direction to form the transmission belt 28. By changing the hanging diameter (effective diameter), the reduction ratio R10 of the CVT 6 can be adjusted.

That is, inside each of the movable pulleys 34 and 36, there is formed a hydraulic chamber which is pressure-fed by a hydraulic pump 40 from a reservoir 38 and changes in volume by hydraulic oil supplied through a pressure control valve 42 and a flow control valve 44. By adjusting the hydraulic pressure of each hydraulic chamber via the pressure control valve 42 and the flow control valve 44, the reduction ratio R10 of the CVT 6 is controlled. The operations of the pressure control valve 42 and the flow control valve 44 for controlling the hydraulic pressure are well known in the related art, and a detailed description thereof will be omitted.

Next, the input / output shafts 20 and 22 of the CVT 6 are provided with rotational speed sensors 46 and 48 for detecting their rotational speeds, respectively.The detection signals from these rotational speed sensors 46 and 48 are electronically controlled. Input to the circuit 60.

The electronic control circuit 60 receives a detection signal from each of the rotation speed sensors 46 and 48, a detection signal from the throttle opening sensor 18 described above, and a detection signal from an accelerator opening sensor 64 provided on an accelerator pedal 62 of the vehicle. A detection signal is also input, and based on these various detection signals, the throttle actuator 16,
Drive control of the pressure control valve 42 and the flow control valve 44 to control the vehicle speed to the target vehicle speed required by the vehicle driver with optimum fuel efficiency, and is known by the CPU 60a, ROM 60b, RAM 60c, input / output port 60d, and the like. As a logical operation circuit.

The input / output port 60d has a drive circuit for driving the throttle actuator 16 in accordance with the control voltage VTH of the throttle actuator 16 calculated in a control amount calculation process described later, and a CVT1 calculated in the control amount calculation process also described later.
The pressure control valve 42 and the flow control valve 44 according to the control voltage VS of 6.
Are provided, and the output torque and the reduction ratio of the internal combustion engine 2 can be controlled via each of these drive circuits.

Next, a control law for vehicle drive system control executed by the electronic control circuit 60 will be described with reference to a block diagram shown in FIG. FIG. 3 is a diagram showing a control law of this embodiment, and does not show a hardware configuration. Actual control is realized by executing a series of control programs shown in a flowchart of FIG. You.

As shown in FIG. 3, in this embodiment, first, the input rotation speed ωIN and the output rotation speed ωOUT of the CVT 6 detected by the rotation speed sensors 46 and 48 are input to the CVT reduction ratio calculation unit P1. The CVT reduction ratio calculation unit P1 calculates the reduction ratio R10 of the CVT 6 based on the input rotation speed ωIN and the output rotation speed ωOUT of the CVT 6 using the following equation (1): R10 = ωIN / ωOUT (1) The result R10 is output to the total reduction ratio calculation unit P2. Then, based on the CVT reduction ratio R10 and the reduction ratio R10D in the drive transmission system from CVT6 to the drive wheels (that is, the reduction ratio of the differential gear) R10D, the total reduction ratio calculation unit P2 calculates the following equation (2) R10T = R10 · R10D Using (2), the total reduction ratio R10T of the power transmission system of the vehicle is calculated.

The output rotation speed ωOUT of the CVT 6 detected by the rotation speed sensor 48 is also input to the vehicle speed calculation unit P3. Then, the vehicle speed calculation unit P3 calculates the output rotation speed ωOUT and the reduction ratio R10D of the differential gear based on the input output rotation speed ωOUT,
The vehicle speed V of the vehicle is calculated using the following equation (3): V = ωOUT / R10D (3)

On the other hand, the accelerator opening θACC indicating the amount of depression of the accelerator pedal 62 detected by the accelerator opening sensor 64 is input to the target vehicle amount calculation unit P4. The target vehicle speed calculation unit P4 calculates the vehicle driving speed based on the input accelerator opening θACC using a map having the accelerator opening θACC as a parameter or the following equation (4): V ⁰ = f1 (θACC) (4) Calculates the target vehicle speed V ⁰ requested by the
Its outputs the calculated result V ⁰ to the running resistance calculating portion P5. Then the running resistance calculating portion P5 is a running resistance FR which occurs when the vehicle was traveling at the target vehicle speed V ^0, preset equation (5) ｛However, CN: running resistance coefficient, AF: whole vehicle projected area, CR:
It calculates using the rolling resistance coefficient, M: vehicle weight｝, and outputs the calculation result (running resistance FR) to the torque-reduction ratio characteristic calculation unit P6.

Torque - speed reduction ratio characteristic calculating unit P6 is a total reduction ratio calculated in each section P2-P5 R10T, the vehicle speed V, the target vehicle speed V ^0, based on the running resistance FR, the following equation (6) Torque represents the relationship between the optimum engine torque TE ⁰ and CVT speed reduction ratio R10 ⁰ to driving the vehicle at the target vehicle speed V ⁰ using - reduction ratio characteristic is calculated, the control target calculating unit P7 the calculation result Output to The arithmetic expression (6) is set based on a physical model representing the behavior of the drive system of the vehicle, and its derivation method and the like will be described later in detail.

Next, the control target calculation unit P7 is a torque-reduction ratio characteristic calculation unit.
Torque output from the P6 - a reduction ratio characteristic data, based on the optimal fuel consumption characteristics set in advance, for controlling the target vehicle speed V ⁰ a vehicle speed V without only be causing shift shock with minimal fuel consumption of the internal combustion engine 2 output torque (target engine torque) TE ⁰ and CVT6 reduction ratio (target speed reduction ratio) is calculated R10 ^0, the result of the calculation TE ⁰ and R10 ⁰ a target input rotational speed calculation unit P8 and the target throttle opening degree calculation unit P10 Output each one.

Target input rotational speed calculation unit P8, based on an output rotational speed OmegaOUT of CVT6 detected by the target reduction ratio R10 ⁰ and the rotational speed sensor 48 which is the input, the following equation ^{(7) ωIN 0 = R10 0} · ωOUT ... (7) input rotation speed (the target input rotation speed) OmegaIN ⁰ of CVT6 necessary to control the CVT speed reduction ratio R10 to the target reduction ratio R10 ⁰ with
The calculation result ωIN ⁰ is output to the CVT control voltage calculation unit P9. Then the CVT control voltage calculator P
9. Based on the target input rotation speed ωIN ⁰ and the actual input rotation speed ωIN of the CVT 6 detected by the rotation speed sensor 46, the following equation (8) is obtained: Vs = K1 · (ωIN ⁰ −ωIN) (8) The CVT control voltage Vs is calculated by using the above.

The target throttle opening calculating unit P10 calculates the input target engine torque TE ⁰ and the target input rotational speed ωIN ⁰
The engine torque TE is set to the target engine torque TE by using a preset map or the following equation (9) θTH ⁰ = f2 (TE ⁰ , ωIN ⁰ ) (9)
⁰ used to calculate the opening (target throttle opening) .theta.TH ⁰ of the throttle valve 12 necessary for controlling the outputs of the calculation result .theta.TH ⁰ the throttle control voltage calculation unit P11. Then, the throttle control voltage calculator P11 calculates the target throttle opening θTH ⁰ and the actual throttle opening θTH detected by the throttle opening sensor 18,
Calculating a throttle control voltage VTH using the following equation (10) VTH = K2 · ( θTH 0 -θTH) ... (10).

Next, a control target is obtained based on the torque-reduction ratio characteristic and the optimal fuel consumption characteristic by the operation expression (6) for obtaining the torque-reduction ratio characteristic in the torque-reduction ratio characteristic calculation part P6 and the control target calculation part P7. Target engine torque TE ⁰ and target reduction ratio R
Procedure, etc. in calculating the 10 ⁰ will be described in detail.

First, the engine speed is ωE, the tire speed is ωT,
The vehicle speed is V, the engine torque is TE, the torque (shaft torque) of the output shaft of the internal combustion engine 2 is TL, the driving torque of the vehicle is TD, the running resistance is FR, the radius of the tire is r, the CVT reduction ratio is R10, and the total deceleration is performed. Assuming that the ratio is R10T, the moment of inertia of the rotating part of the internal combustion engine 2 is IE, the moment of inertia of the power transmission system is IT, and the weight of the vehicle is M, the equations of motion of the internal combustion engine 2, the power transmission system and the vehicle are as follows: It can be described as in equations (11) to (13).

IE · (dωE / dt) = TE−TL (11) IT · (dωT / dt) = R10T · TL−TD (12) M · (dV / dt) = TD / r) −FR (13) The relationship between the engine rotation speed ωE and the wheel rotation speed ωT can be described by the following equation (14) using the total reduction ratio R10T. / dt is as shown in the following equation (15).

Then, using the above equations (11) to (13), ω of the equation (15)
When T, TL, and TD are deleted, the above equation (15) can be transformed into the following equation (16).

The relationship between the engine rotation speed ωE and the vehicle speed V can be described as in the following equation (17) using the total reduction ratio R10T and the tire radius r, so that ωE = V · R10T / r (17) Wheel rotation speed ωE Is the differential value dωE / dt of the following equation (18).

Accordingly, by substituting equation (18) into equation (16), a physical model representing the behavior of the drive system of the vehicle equipped with a continuously variable transmission can be derived as in the following equation (19).

I {R10T}. (DV / dt) = TE-TC {FR, R10T, V} (19) In the equation (19), It is. Then, in the above equation (9), assuming that the state x = V, the input u = TE / I {R10T}, and the output y = V, the system equation of the vehicle drive system is obtained as in the following equations (22) and (23).

y = x (23) Then, the output y of such a system (ie, the vehicle speed V)
The Consider that feedback control of the target vehicle speed V ^0.

First, the output y (that is, the vehicle speed V) is a target value (that is, the target vehicle speed).
When V ⁰ ) becomes steady (t → ∞), state is xs and input is us
Then, these values xs, us are calculated by the above (22) and (23)
From the formula, Becomes Next, the variation from such a steady state is represented by X (= x
−xs), U (= U−us), the above (22) and (23)
Is Becomes Since equations (25) and (26) are controllable and observable, the following equation (27) By obtaining the optimum feedback gain F that minimizes the evaluation function J described in the above, the optimal control law for controlling the vehicle speed V to the target vehicle speed V ⁰ is obtained as in the following equation (28).

Where P is Riccati equation Is a solution that satisfies

As a method of designing such a control law, for example, Katsuhisa Furuta “Digital control of real system”
ol.28, No.12, 1984, the Society of Instrument and Control Engineers, etc.

Next, from the definition of U and X, the above equation (28) Therefore, by rearranging the equation (29), the engine torque TE ⁰ for controlling the vehicle speed V to the target vehicle speed V ⁰ can be obtained.
Is given by the following equation (30).

^{TE 0 = I {R10T} ·} F (V 0 -V) + TC {FR, R10T, V} in ... (30) The equation (30), TC {FR, R10T, V } in the above equation (21) As shown, since the equation (21) includes the differential term of the total reduction ratio R10T,
As shown in the following equation (31), equation (21) is discretized, and the next total reduction ratio R10T is set as a target total reduction ratio R10T ⁰ , Further, the target total reduction ratio R10T ⁰ is the target reduction ratio R10 of CVT6.
^Since it is obtained by multiplying ⁰ and the reduction ratio R10D of the differential gear, the above equation (31) is further modified to the following equation (32).

Then, according to this equation (32) and the above-mentioned equation (20), (30)
By rewriting the equation, optimal to control the vehicle speed V to the target vehicle speed V ^0, the engine torque (target engine torque)
A TE ^0, CVT speed reduction ratio (target speed reduction ratio) R10 ⁰ and relationship represent the aforementioned (6) is obtained by the equation (6), optimal to control the vehicle speed V to the target vehicle speed V ⁰ A torque-reduction ratio characteristic is obtained.

Next, the control target calculation unit P7, as described above, the torque - but is intended to determine the target engine torque TE ⁰ and the target reduction ratio R10 ⁰ based on the reduction ratio characteristics and the optimal fuel consumption characteristics, its The decision is made as follows.

First, as is well known, the relationship between the engine torque TE and the CVT reduction ratio R10 (optimum fuel consumption characteristic) that allows the vehicle to travel efficiently with the minimum fuel consumption is experimentally set as the optimum fuel consumption line shown in FIG. be able to. Therefore, the control target calculating unit P7 calculates the following equation (33) representing the optimal fuel efficiency line.
And f (TE ⁰ , R10 ⁰ ) = 0 (33) Based on the above equation (6), the intersections x1 and x2 between the optimal fuel consumption line and the torque-reduction ratio characteristic shown in FIG. the engine torque TE and the CVT speed reduction ratio R10 corresponding to the intersection x1 or x2 closer from the control amount, respectively, the target engine torque TE ^0, is calculated as the target speed reduction ratio R10 ^0.

Further, as shown in FIG. 4, the upper and lower R10max of the CVT6 actually realizable reduction ratio, since R10min is present, the target reduction ratio R10 ⁰ to calculate the control target calculation unit P7 following formula (34) R10min ≦ R10 ⁰ ≦ R10max ... such constraints (34) is present, the target reduction ratio R10 ^0, the lower limit value
R10min (for example, 0.43) or more and upper limit value R10max (for example, 2.5
0) The following values must be set. Therefore in the control target calculation unit P7, the optimum fuel consumption line and the torque reduction ratio characteristics and the target reduction ratio R10 ⁰ determined based on the above (3
If the constraint conditions in Equation 4) are not satisfied, the engine torques TE and CVT that satisfy the constraint conditions and are closest to the characteristics are satisfied.
The reduction ratio R10 is set to the target engine torque TE ⁰ and the target reduction ratio.
It is set as R10 ^0.

The control law for the drive system control and the design procedure thereof according to the present embodiment have been described above in detail. Next, the control amount calculation processing executed by the electronic control circuit 60 in realizing this control law will be described with reference to FIG. Will be described along the flowchart of FIG.

This processing is performed for a predetermined time (for example, 8 ms
c.) In the process executed every time, when the process is started, first, Step 100 is executed, and various detection data obtained based on the detection signals from the respective sensors, that is, the input rotation speed ωIN of the CVT 6 and the output The rotational speed ωOUT, the throttle opening σTH, and the accelerator opening θACC are read, and the routine proceeds to step 110.

In step 110, based on the read input rotational speed ωIN and output rotational speed ωOUT of CVT6,
The processing as the CVT reduction ratio calculation unit P1 for calculating 10 is executed. In the following step 120, the calculated CVT reduction ratio
Based on R10 and the differential gear reduction ratio R10D stored in advance in the ROM 60b, a process is executed as a total reduction ratio calculation unit P2 that calculates a total reduction ratio R10T. In the following step 130, the processing as the vehicle speed calculating section P3 for calculating the vehicle speed V based on the output rotational speed ωOUT of the CVT 6 read in step 100 and the above-mentioned reduction ratio T10D is executed, and the routine proceeds to the following step 140.

Based on step 140 the accelerator opening θACC read in step 100, executes the processing as the target vehicle speed calculating section P4 for calculating a target vehicle speed V ^0, the process proceeds to the next step 150, the target vehicle speed V ⁰ The calculated And vehicle weight data M, running resistance coefficient data CN, stored in the ROM 60b in advance.
Based on the rolling resistance coefficient data CR and the vehicle front projected area data AE, a process is executed as the running resistance calculation unit P5 for calculating the running resistance FR using the above-described equation (5), and the routine proceeds to step 160. Then, in step 160, step
Total reduction ratio R10T, vehicle speed V, obtained from 120 to step 150,
Based on the target vehicle speed V ⁰ and the running resistance FR, a process is executed as the torque-reduction ratio characteristic calculation unit P6 for calculating the torque-reduction ratio characteristic by using the above-mentioned equation (6), and the routine proceeds to step 170. .

In step 170, based on the calculated torque-reduction ratio characteristic and the optimal fuel consumption characteristic (the optimal fuel consumption line shown in FIG. 4) stored in advance in the ROM 60b, the target engine torque TE ⁰ and target reduction ratio R10
The processing as the control target calculation unit P7 for calculating ⁰ is executed.

Then, in the following step 180, the target reduction ratio R obtained above
10 ⁰ and output rotational speed ωOU of CVT6 read in step 100
Based on T, calculate a target input rotation speed ωIN ⁰ of CVT6, execute processing as a target input rotation speed calculation unit P8,
Proceeding to step 190, the target input rotational speed ωI
Based on N ⁰ and the actual input rotation speed ωIN of the CVT 6 read in step 100, a process is performed as a CVT control voltage calculation unit P9 for calculating a CVT control voltage Vs.

In the following step 200, the target throttle opening θTH ⁰ is calculated based on the target engine torque TE ⁰ obtained in step 170 and the target input rotational speed ωIN ^{0 of} the CVT 6 obtained in step 180. executing the processing of the part P10, the processing proceeds to subsequent step 210, based on the actual throttle opening .theta.TH read in the target throttle opening .theta.TH ⁰ and step 100 to calculate the throttle control voltage VTH, throttle control The processing as the voltage calculation unit P11 is executed, and the processing is temporarily ended.

The control voltages VS and VTH calculated in steps 190 and 210 are used to control the reduction ratio R10 of the CVT 6 and the throttle opening θTH by the drive circuit provided in the input / output port 60d as described above. .

In this embodiment, the RO that stores the optimal fuel economy characteristics is
M60b is the optimal fuel consumption characteristic storage means M1, and the accelerator opening θACC
From the target vehicle speed V ⁰ processing target vehicle speed setting means M2 in step 130 to set, the process running state detecting means M3 for the various sensors and steps 100 130 for detecting a running condition of the vehicle, the torque - speed reduction ratio characteristic process of step 160 for calculating the torque - the speed change ratio characteristic calculation means M4, the torque - the process of step 170 for calculating the target engine torque TE ⁰ and a target reduction ratio R10 ⁰ based on the reduction ratio characteristics and optimal fuel consumption line is controlled the amount calculation means M5, the process of step 180 to step 210 for controlling the throttle opening θTH and the input rotational speed ωIN seek control voltage Vs and VTH based on the target engine torque TE ⁰ and a target reduction ratio R10 ^0, input-output port 60d The drive circuit, the pressure control valve 42, the flow control valve 44, and the throttle actuator 16 correspond to the control means M6, respectively.

As described above, in the present embodiment, the target vehicle speed V ⁰ is set according to the depression amount of the accelerator pedal 62 operated by the vehicle driver (that is, the accelerator opening θACC), and the target vehicle speed V ⁰ is set based on the set target vehicle speed V ⁰ . optimum torque to control vehicle speed V to the target vehicle speed V ⁰ - calculates the reduction ratio characteristics, the torque - based on the optimal fuel consumption characteristics which are preset reduction ratio characteristic target engine torque TE ⁰ and a target reduction ratio R10 By calculating ⁰ , the engine torque TE and the CVT reduction ratio R10 are controlled.

For this reason, according to the present embodiment, the vehicle speed can be controlled to a constant vehicle speed with optimal fuel efficiency according to the amount of depression of the accelerator pedal by the vehicle driver. The vehicle speed can be controlled to a desired target vehicle speed without adjusting the amount. The arithmetic expression (6) for calculating the torque-reduction ratio characteristic is set based on a physical model representing the behavior of the vehicle drive system, and the amount of change from the current total reduction ratio R10T (that is, the aforementioned differential term) ) to the torque taking into account the - it is possible to calculate the reduction ratio characteristics, the control target, i.e. the target engine torque TE ⁰ and a target reduction ratio R10 ⁰ is possible to set an optimum value without causing a shift shock becomes possible, it is also possible to control the target vehicle speed V ⁰ a vehicle speed V without causing shift shock during vehicle running.

Here, in the above embodiment, when the running resistance R of the vehicle is calculated, the running resistance coefficient CN and the rolling resistance coefficient CR are described as using predetermined values. However, these coefficients are actually used. The coefficient may be corrected by detecting various kinds of disturbances because the coefficient varies depending on disturbances such as a gradient of a traveling road, a wind direction, and a road surface condition.

[Effects of the Invention] As described above, in the vehicle drive system control device of the present invention, the target vehicle speed requested by the vehicle driver is set from the accelerator operation amount of the vehicle driver, and based on the set target vehicle speed. An optimum torque-reduction ratio characteristic for controlling the vehicle speed to the target vehicle speed is calculated, and a target engine torque and a target reduction ratio are calculated based on the torque-reduction ratio characteristic and the optimal fuel efficiency characteristic, and the torque of the internal combustion engine and the target torque are calculated. The speed reduction ratio of the step transmission is feedback-controlled. Therefore, according to the present invention, it is possible to control the vehicle speed to a constant vehicle speed with optimum fuel efficiency according to the depression amount of the accelerator pedal by the vehicle driver. It is possible to control the vehicle speed to a desired target vehicle speed without adjusting the vehicle speed. Further, in particular, in the present invention, the arithmetic expression for calculating the torque-reduction ratio characteristic is the above-described expression including the inertia moment of the internal combustion engine and the power transmission system and the differential term of the reduction ratio of the power transmission system. Since it is set based on the physical model describing the behavior, it is possible to calculate the torque-reduction ratio characteristic, and consequently the target engine torque and the target reduction ratio, in consideration of the amount of change in the reduction ratio and the inertia of the vehicle drive system. it can. Therefore, according to the present invention, it is possible to control the vehicle speed while always driving the internal combustion engine with the optimum fuel efficiency characteristics, and to reduce the vehicle speed without generating a shift shock even when the target vehicle speed changes suddenly. It is possible to control to the target vehicle speed.

[Brief description of the drawings]

FIG. 1 is a block diagram illustrating the configuration of the present invention, FIG. 2 is a schematic configuration diagram showing the overall configuration of a vehicle drive system control device according to an embodiment, and FIG. 3 is a vehicle drive system executed by an electronic control circuit. FIG. 4 is a block diagram showing a control law for control, FIG. 4 is a diagram illustrating a procedure for calculating a target engine torque and a target reduction ratio from the torque-reduction ratio characteristics and the optimum fuel consumption characteristics, and FIG.
FIG. 5 is a flowchart illustrating a control amount calculation process executed by the electronic control circuit. M1: Optimum fuel consumption characteristic storage means M2: Target vehicle speed setting means M3: Running state detecting means M4: Torque-reduction ratio characteristic calculating means M5: Control amount calculating means, M6: Control means E / G, 2 … Internal combustion engine T / M, 6… Continuously variable transmission (CVT) 16… Throttle actuator 18… Throttle opening sensor 42… Pressure control valve, 44… Flow control valve 46, 48… Rotational speed Sensor 60: Electronic control circuit, 64: Accelerator opening sensor

Claims (1)

(57) [Claims] 1. A control device for a vehicle drive system having an internal combustion engine as a drive source and a continuously variable transmission capable of continuously adjusting a reduction ratio in a power transmission system, wherein fuel efficiency is minimized when the vehicle is running. An optimal fuel efficiency characteristic storing means in which an optimal fuel efficiency characteristic describing a relationship between the engine torque and the reduction ratio is stored in advance; a target vehicle speed setting means for setting a target vehicle speed of the vehicle based on an accelerator operation amount by a vehicle driver; Traveling state detection means for detecting a traveling state of the vehicle including the reduction ratio of the continuously variable transmission and the vehicle speed of the vehicle; and a detection result of the traveling state detection means and a target vehicle speed set by the target vehicle speed setting means. The optimum engine torque and reduction for controlling the vehicle speed to the target vehicle speed are calculated by using an arithmetic expression set based on a physical model that describes the behavior of the vehicle drive system using the vehicle speed as a state variable and A torque-reduction ratio characteristic calculating means for calculating a torque-reduction ratio characteristic representing a relationship with a speed ratio; I {R10T}. (DV / dt) = TE-TC (FR, R10T, V) R10T is the total reduction ratio of the power transmission system including the reduction ratio of the continuously variable transmission, V is vehicle speed, TE is engine torque, FR is running resistance, M is vehicle weight, r is tire radius, and IT is power transmission. The moment of inertia of the system, IE, represents the moment of inertia of the rotating part of the internal combustion engine. Control amount calculating means for calculating a target engine torque and a target reduction ratio for controlling a vehicle speed to a target vehicle speed with a minimum fuel consumption based on the calculated torque-reduction ratio characteristics and the optimum fuel efficiency characteristics; Control means for feedback-controlling the torque of the internal combustion engine and the reduction ratio of the continuously variable transmission in accordance with the target engine torque and the target reduction ratio calculated by the means. .