JPS62199534A - Control device for vehicle drive system - Google Patents

Abstract

PURPOSE:To aim at enhancing the economy of fuel efficiency, by computing a desired engine torque and a desired input side rotational speed so that a torque changing means is controlled to make the actual engine torque become equal to the desired torque while a continuously variable transmission is controlled to make the actual input side rotational speed become equal to the desired rotational speed. CONSTITUTION:During running of a vehicle, a computing unit 100 computes a desire horse power PS deg. in accordance with an accelerator opening degree thetaac and a vehicle speed V. Then a computing unit 102 computes a desired engine torque Te deg. from the desired horse power PS deg., and a control system 104 controls a throttle actuator 19 such that an actual engine torque Te becomes equal to the desired engine torque Te deg.. Further, a computing unit 106 computes a desired input side rotational speed Nin deg. from the actual engine torque Te. Further, a control system 10 performs feed-back control of the opening degree of a flow control valve for controlling the inflow and discharge amounts of oil fed to the input side movable pulley of the stepless speed change gear, thereby the actual input side rotational speed Nin of the stepless speed change gear becomes equal to the desired input side rotational speed Nin deg..

Description

[Detailed description of the invention]

[Industrial Application Field 1] The present invention relates to a control device for a vehicle drive system, and particularly relates to an engine having means for changing engine torque independently of an accelerator pedal, and a speed ratio (output side rotational speed/input side rotational speed/input side rotational speed). The present invention relates to an improvement of a control device for a vehicle drive system equipped with a continuously variable transmission capable of steplessly controlling the side rotational speed. 2. Description of the Related Art As one type of automatic transmission mechanism for vehicles, there is a continuously variable transmission mechanism driven by a belt or the like. This continuously variable transmission generally has a V-shaped boob device on the input shaft and output shaft, respectively, which consists of a fixed boob and a movable boob, and whose effective diameter is variable by a hydraulic servo device. between the boolean devices
l) The rotation of the input shaft can be transmitted to the output shaft in a stepless manner by means of a transmission belt. Normally, the oil flow to the hydraulic servo device on the input side is changed by a flow control valve to forcibly change the effective diameter of the V-shaped boob device on the input side. The hydraulic pressure is changed by a pressure control valve so that torque can be transmitted without the transmission belt slipping in accordance with the change in the effective diameter of the input side V-shaped boob device. One of the major purposes of introducing such a continuously variable transmission+14 in the drive system of a vehicle is to always run the vehicle in the so-called optimum fuel efficiency line (see Fig. 9) within the engine usage range. The aim is to improve the fuel efficiency of actual vehicles, and various developments have already been made in the past.

Problem 1 to be Solved by the Invention However, the reality is that all of the conventionally disclosed techniques still leave room for improvement. Example EVA, JP 11r459 32642, discloses a method in which the vehicle always travels on the optimal fuel efficiency diagram, including during transient periods of cl'3, but in this method,
There is a problem in that the output torque is insufficient during a shift transition, which deteriorates driving performance, particularly acceleration performance. Also, ′+? In the i-ma 58-39870, the vehicle runs on the optimum fuel economy line in steady state, but on the other hand, during the shift transition, the response of the continuously variable transmission 1i, l is slower than that of the throttle actuator, so in reality, the speed change as shown in Fig. 10 occurs. A method is disclosed in which the operation is as shown by the broken line, resulting in a deviation from the optimum fuel economy line A, and the driving performance is superior to that of the above-mentioned Tamabun Sho 59-32642. However, as shown in FIG. There is a problem in that T tends to be qualitatively large. [Objective of the Invention] The present invention has been made in view of such conventional problems, and aims to ensure good running performance during transient times. The purpose of the present invention is to provide a control system for a vehicle drive system that can reduce the deviation from the optimum fuel efficiency line during steady state and ensure excellent fuel efficiency. [Means for determining YK] The first invention provides a vehicle drive system that includes an engine that has means for changing the engine torque by 1q independently of the accelerator pedal, and a continuously variable transmission that can control the speed ratio steplessly. In the control device, the accelerator opening, single engine, engine torque,
and means for detecting the input side rotational speed of the continuously variable transmission, means for determining a target engine torque of the means capable of changing the engine torque in relation to at least the accelerator opening and the single engine, and at least the actual engine torque. means for determining a target input side rotational speed of the continuously variable transmission that achieves optimal fuel efficiency in relation to the above, and controlling means for changing the engine torque so that the actual engine torque becomes the target engine torque. In addition, the above object is achieved by controlling the continuously variable transmission so that the actual input side rotational speed becomes the target input side rotational speed. The second invention also provides a vehicle drive system that is equipped with an engine that has means for changing the engine torque independently of the accelerator pedal, and a continuously variable transmission that can control the speed ratio steplessly. The system control device includes means for detecting accelerator opening, vehicle speed, engine torque, input side rotational speed of the continuously variable transmission, and output side rotational speed of the automatic transmission, and at least means for detecting accelerator opening and vehicle speed. means for determining a target engine torque of the means capable of changing the engine torque based on the actual engine torque; means for determining a target input side rotational speed of the continuously variable transmission that provides optimum fuel efficiency in relation to at least the actual engine torque; means for determining a target speed ratio between the input and output sides of the continuously variable transmission from the input side rotational speed and the actual output side rotational speed, and adjusting the engine torque so that the actual engine torque becomes the target engine torque. By controlling the variable means and controlling the continuously variable transmission so that the actual speed ratio becomes the target speed ratio,
This also achieved the above objectives. In addition, in the above configuration, "an engine that has a means to change the engine torque independently of the accelerator pedal" means
[An engine in which the engine torque is not determined uniquely by the accelerator opening, and can generate different engine torques by changing the intake air m depending on various driving conditions even with the same accelerator opening.] ” means. Therefore, some of these types of engines include so-called linkless engines in which the accelerator pedal and the means to actually change the engine torque, such as the throttle valve, are completely independent, as well as engines in which the accelerator pedal and the throttle valve are linked, for example. This also includes types of engines that change the engine torque even with the same accelerator opening by opening and closing bypass valves, etc. depending on the driving conditions. Bypass valve
is the means to change the engine torque.

[Operation] In the first invention, the accelerator opening degree, vehicle speed, actual engine torque, and actual input side rotation speed are detected 4, and the target engine torque is determined mainly in relation to the accelerator opening degree and the vehicle speed. , determine the target input side rotational speed of the continuously variable transmission that provides the optimum fuel efficiency in relation to the actual engine torque, and change the engine torque so that the actual engine torque becomes the target engine torque (1!). In addition, the continuously variable transmission described in item 11 is controlled so that the actual input side rotational speed becomes the target input side rotational speed. It is possible to achieve both improvement in fuel consumption rate. This situation is shown in FIGS. 7 and 8. In other words, the engine torque rise during the transient period is extremely good as shown by the broken line (Fig. 7), and when the deviation on the engine torque side is δ and the deviation in the continuously variable transmission is β, The deviation γ- from the target operating point P is qualitatively smaller than the conventional deviation γ (FIG. 8). That is, it is possible to retain the advantages of both the above-mentioned Japanese Patent Application Laid-open No. 59-32642 and No. 58-39870, while eliminating the disadvantages. On the other hand, in the second invention, the actual input side rotation speed of the continuously variable transmission is controlled to the target input side rotation fA degree in the first invention, but instead of this, the actual input side rotation speed of the continuously variable transmission is controlled to the target input side rotation fA degrees. The speed ratio is controlled to a target speed ratio. Thereby, in controlling the continuously variable transmission, it is possible to obtain the same effect as the first invention while also reflecting the element of the rotational speed on the output side. In the first and second aspects of the invention, a preferred embodiment is that the means for changing the engine torque 1q is a throttle actuator. Further, in a preferred actual TM aspect, the means for changing the engine torque is a fuel injection pump of a diesel engine. Embodiments Embodiments of the present invention will be described in detail below with reference to the drawings. FIG. 2 does not show an overall outline of an automobile engine and a continuously variable transmission to which an embodiment of the vehicle drive system control device according to the present invention is applied. In the figure, an output shaft 2 of an engine E/G is connected to a belt-driven continuously variable transmission (hereinafter referred to as CVT) via a clutch isoyoko 4. This CVT is provided with a V-shaped pulley device 10.14 on the input shaft 6 and the output shaft 8, each consisting of a fixed pulley 11.15 and a movable pulley 12.16. The input-side fixed pulley 11 is fixed to the input shaft 6, and the input-side movable pulley 12 is connected to the outer periphery of the input shaft 6 via a spline, a ball bearing, etc. so as to be movable in the axial direction. Similarly, the output side fixed pulley 15 is fixed to the output shaft 8, and the output side movable pulley 16 is fitted on the outer periphery of the output shaft 8 with a spline, a ball bearing, etc. so as to be movable in the axial direction. The pressure-receiving area of each movable pulley 12.16 is set such that input side>output side, and the effective diameter can be forcibly changed to change the speed ratio on the input side. Further, the axial arrangement of the fixed pulley 11.15 and the movable pulley 12.16 on the input side and the output side is reversed to each other, so that the transmission belt 18 always hangs at right angles to the person and the output shield 6.8. It's Nishide. The opposing surfaces of the fixed pulley 11.15 and the movable pulley 12.16 are formed on tapered surfaces increasing the distance from each other radially outwards. Further, a transmission belt 18 having an isosceles trapezoidal cross section is used as a V-shaped boob device 10.1 on the input side and the output side.
It can be hung between 4. The radial contact position of the transmission belt 18 on the boot surface changes continuously as the clamping force of the fixed and movable boot of each V-shaped boot device 10.14 changes. Input side V
When the contact position of the transmission belt 18 on the type booby device 10 moves radially outward, the contact position of the transmission belt 18 on the output side V-type booby device moves radially inward, and the speed 1 ratio of the CVT increases. e (=rotational speed No. of output shaft 8
ut/rotational speed N in of the input shaft 6 increases, and in the opposite case the speed ratio e decreases. The power of the output 1 sleeve 8 is transmitted to the driving wheels via an idler gear for forward/reverse switching, a gear for deceleration, a differential gear, etc. (not shown). On the other hand, the accelerator pedal sensor 34 detects the opening degree Oac of the accelerator pedal 36 depressed by the driver's foot 35. Also, the opening degree of the engine E/G intake throttle is
It is controlled by a throttle actuator 19 independent of the accelerator pedal 36. The input side and output side rotation angle sensors 2o and 21 respectively detect the rotation angle of the pulley 11.16, and as a result, the rotation speed (
Output side time! The vehicle speed V) is detected from the 1I7A speed. Further, the torque sensor 22 is provided on the input shaft 6, and the input! Detect the engine torque at J5 at 1+116. The pressure control 6+1 valve 24 controls the release of oil as a hydraulic medium sent from the reservoir 26 via the oil path 27 by the oil pump 25 to the oil path 28, thereby controlling the line of the oil path 29. Adjust the pressure PL. Line pressure PL is supplied to the hydraulic servo device of the output side movable pulley 16 via an oil passage 29 . The flow control valve 30 controls the flow of oil into and out of the input movable pulley 2. In order to maintain the speed ratio e of the CVT constant, the oil passage 33 is disconnected from the line pressure oil passage 31 and the drain oil passage 32 that branch from the oil passage 29. As a result, the axial position of the input movable pulley 12 is maintained constant, and the 3a degree ratio e is also maintained constant. Further, in order to increase the speed ratio e, oil is supplied from the line pressure oil passage 31 to the hydraulic servo device of the input side movable pulley 12 via the oil passage 33. As a result, the clamping force between the input pulleys 11 and 12 is increased, and the input pulley 1
The contact position of the transmission belt 18 on the 1.12 plane moves radially outward, increasing the speed ratio e. Conversely, in order to reduce the speed ratio e, the oil in the hydraulic servo device of the input movable pulley 12 is conducted to the atmosphere through the drain oil passage 32, and the input pulleys 11 and 12 are tightened. Try to reduce the force. Although the oil pressure in the oil passage 33 is lower than the line pressure PL, as described above, the piston pressure receiving area of the hydraulic servo device of the input side movable pulley 12 is set to be larger than the piston pressure receiving area of the hydraulic servo device of the output side movable pulley 16. Therefore, the tightening force of the input pulleys 11 and 12 is reduced to the output pulley 15.
．． It is possible to increase the tightening force more than 16. By changing the tightening force of the input pulley 11.12 with the flow control valve 30, the effective diameter between the input pulleys 11.12 is changed, while the output pulley 15.16
The transmission belt 18 follows the change in the effective diameter on the input side.
The line pressure PL is regulated by the pressure control valve 24 so that a tightening force is generated that ensures torque transmission without slipping. The electronic control unit 38 includes a D/A converter 40, an input interface 41, an A/D converter 42, and a CPLJ 43, which are connected to each other by an address data bus 39.
, RAM44, and ROM45. Analog output θaC of accelerator pedal sensor 34 and torque sensor 2
The analog output Te of 2 is sent to the A/D converter 42, and the pulses of the rotation angle sensor 20.21 are sent to the input interface 41. throttle actuator 19,
Control voltage Vt to flow control valve 30 and pressure control valve 24
h%Vin and Vout are sent from the D/A: ] inverter 40 via amplifiers 49, 50, and 51, respectively. FIG. 3(A) shows the relationship between the input voltage and output current of the amplifier 49 for the throttle actuator 19, and FIG.
B) shows the relationship between the input current of the throttle actuator 19 and the intake throttle opening. Therefore amplifier 4
The throttle opening increases in proportion to the input voltage of 9. 4(A) shows the relationship between the input voltage and output current of the amplifier 50 for the flow control valve 30, and FIG. 4(B) shows the relationship between the input current of the flow control valve 30 and the input side hydraulic servo of the movable pulley 12. shows the relationship between the flow rate and the flow rate. Therefore, the speed ratio e is proportional to the change in the input current of the amplifier 50. Figure 5 (A> shows the relationship between the input voltage and output current of the amplifier 51 for the pressure control valve 24, and Figure 5 (B) shows the relationship between the input current of the pressure control valve 24 and the line pressure PL. Therefore, the line pressure PL changes linearly with the change in the input voltage of the amplifier 51.The input 't of the pressure control valve 24
Even if the ki flow is zero, the line pressure PL is maintained at the predetermined value PL+, so even if a wire breakage or a malfunction occurs in the lightning control device 38, the predetermined hydraulic pressure is applied to the hydraulic servo of the control J pulley 12.16. is supplied to ensure minimum torque transmission in the CVT. FIG. 1 shows a block diagram of the control system of this device. In the figure, a block 100 indicates a computing unit that calculates the target output horsepower PS' from the accelerator opening θaC and the vehicle speed V using a formula or a map. Block 102 indicates a computing unit that calculates the target engine torque Te° from the target output horsepower ps. This calculation method is preferably set to the ra optimum fuel consumption line as shown in FIG. 9, for example. Figure D J5 A T solid line C shows the constant fuel consumption rate KA (g/PS - H), and the broken line shows the constant horsepower line (PS). In block 104, the actual engine torque Te becomes the target engine torque Te°. , shows a control system for controlling the throttle actuator 19. For this control, an equation such as equation (1) is used, for example. 1)
Here, vth represents a control voltage at the throttle actuator 19, and kl represents a constant. The block 108 indicates a calculation unit that determines the target input side rotational speed Nin'' from the actual engine torque Te. In this case, it is preferable to determine the target input side rotation speed Nin, for example, along the optimum fuel consumption line A in FIG. 9. The flow rate control valve 3 is adjusted so that the actual input side rotational speed Nin becomes the target input side rotational speed Nin°.
A control system is shown in which the speed ratio e of the CVT is controlled t21I by feedback-adjusting the control voltage Vin of 0. For this control, an arithmetic expression such as the expression <2> is used, for example. Vin-k 2 (Nin' -Nin) --(2
) In addition, in this control, correction is made according to oil temperature, etc., and 16 is free to use a more accurate shore tightening type. In addition, in the block ] 00, the target output horsepower PS
' may be modified or changed using other factors such as road slope, vehicle weight, external switch (economy pattern, power pattern, etc. selection switch) as a parameter. Also, in block 102, the target engine torque Te
' may be modified or changed using other factors such as vehicle speed, engine cooling water center, running road slope, vehicle weight, external switch, air-fuel ratio, etc. as parameters. Furthermore, in obtaining the block, the target input side rotational speed Ni
n° may be modified or changed using other factors such as vehicle speed, engine cooling water temperature, air-fuel ratio, running road slope, vehicle weight, external switch, etc. as parameters. FIG. 6 shows a flowchart of the above control. First, in step 200, accelerator opening θaC1 vehicle speed V, input side rotation speed Nin, engine rotation speed TUNe
is read. Next, in step 202, the target output horsepower PS° is determined as a function of the accelerator opening 0aCX and the vehicle speed V.
It is determined as f1. Thereafter, in step 204, the target engine torque Tc'' is changed to J3 in step 202.
It is obtained as a function f2 of the target output horsepower PS' obtained by In step 206, step 204
Throttle actuator 190 control 211m pressure ■t using target engine torque Te° determined by J5.
l) is obtained by calculating 2k + (Te"Te). In step 208, the target input side rotational speed Nin° is obtained as a function f3 of the actual engine torque Te. In addition, in step 210, the flow rate The control voltage Vin of the control well 30 is determined by the equation k 2 (Nin' - Ni
II). According to the above-described embodiment, as described above with reference to FIG. 7, the engine torque rises slowly (see the broken line) during a transient period, and good running performance can be ensured. Further, as described above with reference to FIG. 8, control can be performed to the target optimum fuel efficiency line A with a smaller deviation γ- than before in steady state. Note that the present invention can also be applied to a drive system in which engine torque is controlled by other means without using a throttle actuator. For example, even in a drive system such as a diesel engine where engine torque is controlled by fuel injection DAm, the object of the present invention can be achieved as is. Furthermore, in the above embodiment, the input side rotational speed of the CVT was controlled to be the target input side rotational speed (
(first invention), the CVT speed ratio e is the target speed ratio e°
The object of the present invention can be achieved in the same manner even if the control is performed so that J: (second invention). In this case, the target speed ratio e° can be obtained as Nout/N group° (Nout is the output side rotational speed of the continuously variable transmission), and the flow rate control valve 30
The control voltage Vin can be calculated as 3(c''-e) and -C. (Effects of the Invention) As explained above, according to the present invention, the control voltage Vin can be obtained with a simple configuration both in steady state and in transient state. Output torque can be controlled appropriately, and excellent effects can be obtained in that it becomes possible to improve both fuel efficiency and power performance.

[Brief explanation of drawings]

Fig. 1 is a block diagram showing the configuration of an embodiment of a control device for a vehicle drive system according to the present invention, and Fig. 2 shows an overall outline of an automobile engine and a continuously variable transmission to which the above embodiment is applied. The skeleton diagram, Figure 3 (A) is a diagram showing the input/output characteristics of the throttle actuator amplifier used in the above embodiment, and Figure 3 (B) is a diagram showing the input and output characteristics of the throttle actuator and the throttle opening. Figure 4 (A) is a diagram showing the input/output 1q characteristics of the amplifier for the flow control valve, and Figure 4 (8) is the diagram showing the relationship between the input of the flow control valve and the CVT. Figure 5 <A) shows the input/output characteristics of the ljQ width transducer for the pressure regulating valve, and Figure 5 (B) shows the relationship with the speed ratio. FIG. 6 is a flowchart showing the control routine, and FIGS. 7 and 8 show the relationship between engine rotational speed and engine torque in the above embodiment device. Figure 9 is a diagram showing the optimum fuel efficiency line.
Figures 10 and 11 are equivalent to Figures 7 and 8, showing the relationship between engine rotational speed and engine torque, in order to explain the technology disclosed in JP-A-58-39870 and its defects. It is a line diagram. E/G...engine, 6...input shaft, 8...output shaft, 22...torque sensor, θaC...accelerator opening, ■...vehicle speed, Nin...input side rotation Speed, Nin''...Target input side rotational speed, Te...Engine torque, Te'...Target engine torque, e...Speed ratio, eo...Target speed ratio.

Claims (4)

[Claims] (1) In a control device for a vehicle drive system equipped with an engine that has a means for changing engine torque independently of the accelerator pedal and a continuously variable transmission that can control the speed ratio steplessly, the accelerator opening and vehicle speed are controlled. , means for detecting engine torque and input side rotational speed of the continuously variable transmission, and means for determining a target engine torque of the means for changing the engine torque in relation to at least the accelerator opening degree and the vehicle speed; means for determining a target input side rotational speed of the continuously variable transmission that provides optimum fuel efficiency in relation to the actual engine torque, and is capable of changing the engine torque so that the actual engine torque becomes the target engine torque. A control device for a vehicle drive system, characterized in that the control device controls the continuously variable transmission so that the actual input side rotation speed becomes the target input side rotation speed. (2) In a control device for a vehicle drive system that includes an engine that has a means for changing engine torque independently of the accelerator pedal and a continuously variable transmission that can control the speed ratio steplessly, , means for detecting engine torque, an input side rotational speed of the continuously variable transmission, and an output side rotational speed of the automatic transmission, and a target engine of the means for changing the engine torque in relation to at least the accelerator opening degree and the vehicle speed. means for determining torque; means for determining a target input side rotational speed of the continuously variable transmission that provides optimum fuel efficiency in relation to at least the actual engine torque; and the target input side rotational speed and the actual output side rotational speed. means for determining a target speed ratio between the input and output sides of the continuously variable transmission from A control device for a vehicle drive system, characterized in that the control device controls the continuously variable transmission so that the target speed ratio is the same as the target speed ratio. (3) The vehicle drive system control device according to claim 2, wherein the means for changing the engine torque is a throttle actuator. (4) The vehicle drive system control device according to claim 2, wherein the means for changing the engine torque is a fuel injection pump in a diesel engine.