JP2013132958A - Control device for vehicle - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a control device for a vehicle including an engine and an automatic transmission, the control device suppressing a deterioration in the fuel economy while reflecting the accelerator operation by a driver to drive of the engine.SOLUTION: The control device for a vehicle restricts a target throttle opening to an upper limit throttle opening or less of a pedal upper limit throttle opening determined based on an accelerator opening, or an operating point upper limit throttle opening determined based on a fuel economy optimum line Lef set in advance, whichever the larger. As a result, the size of the target throttle opening is allowed at least to the pedal upper limit throttle opening, providing an advantage of easily reflecting the accelerator operation by the driver to the engine drive immediately. Furthermore, when the operating point upper limit throttle opening exceeds the pedal upper limit throttle opening, the target throttle opening is restricted by the operating point upper limit throttle opening, the engine operating point is therefore prevented from largely deviating from the fuel economy optimum line Lef, to suppress the deterioration in the fuel economy.

Description

  The present invention relates to drive control of an engine in a vehicle including an engine and an automatic transmission.

  2. Description of the Related Art Conventionally, a vehicle control device used in a vehicle including an engine and an automatic transmission that transmits power of the engine to driving wheels is well known. For example, this is the vehicle control device disclosed in Patent Document 1. In Patent Document 1, the automatic transmission is a continuously variable transmission, and the vehicle control device of Patent Document 1 calculates a target engine torque based on a target driving force and a gear ratio of the automatic transmission, A target throttle opening is calculated based on the target engine torque and the engine speed. The vehicle control device performs feedback control so that the gear ratio of the automatic transmission becomes a target gear ratio of the automatic transmission calculated based on the accelerator opening and the vehicle speed.

Japanese Patent Laid-Open No. 11-001135 JP-A-11-082084

  When the target throttle opening is set and the engine throttle control is performed as in the vehicle control device of Patent Document 1, the target is set so that the engine operating point does not greatly deviate from the optimum fuel consumption line of the engine. It is conceivable to provide an upper limit value for the throttle opening and limit the range of the target throttle opening by the upper limit value. For example, if the operating point of the engine greatly deviates from the optimum fuel consumption line toward the high engine torque side, the fuel consumption of the engine may deteriorate and engine vibration or the like may increase. However, simply setting an upper limit value for the target throttle opening based on the optimum fuel consumption line limits vehicle drivability such as acceleration response due to the limitation of the target throttle opening based on the upper limit value. The possibility was assumed. Such a problem is not yet known.

  The present invention has been made against the background of the above circumstances, and the object of the present invention is to provide a vehicle equipped with an engine and an automatic transmission while reflecting the driver's accelerator operation on the engine drive. An object of the present invention is to provide a vehicle control device that can suppress the deterioration of fuel consumption.

  The subject matter of the first invention for achieving the above object is as follows: (a) In a vehicle including an engine and an automatic transmission that transmits the power of the engine to driving wheels, the target driving force and the automatic transmission A target throttle opening of the engine based on the target gear ratio of the vehicle, wherein (b) a first throttle opening upper limit value determined based on the accelerator opening, The target throttle opening is limited to be equal to or less than a larger throttle opening upper limit value of the second throttle opening upper limit value determined based on the set fuel efficiency optimum line.

  In this way, since the target throttle opening size is allowed at least up to the first throttle opening upper limit value, the driver's accelerator operation is easily reflected in the driving of the engine. is there. Further, when the second throttle opening upper limit value exceeds the first throttle opening upper limit value, the target throttle opening is limited by the second throttle opening upper limit value. It is possible to suppress the point from greatly deviating from the fuel efficiency optimal line. In short, by using the first throttle opening upper limit value or the second throttle opening upper limit value, it is possible to suppress the deterioration of fuel consumption of the engine while reflecting the driver's accelerator operation in the driving of the engine. The fuel consumption is, for example, a travel distance per unit fuel consumption, and the improvement in fuel consumption is an increase in the travel distance per unit fuel consumption, or the fuel consumption rate ( = Fuel consumption / drive wheel output) is reduced. Conversely, the reduction (deterioration) in fuel consumption means that the travel distance per unit fuel consumption is shortened, or the fuel consumption rate of the entire vehicle is increased.

  Here, the gist of the second invention is the vehicle control device according to the first invention, wherein the automatic transmission is a continuously variable transmission. In this way, there is an advantage that the engine is easily driven according to the optimum fuel consumption line as compared with the stepped transmission.

  The gist of the third invention is the vehicle control device of the first invention or the second invention, wherein the second throttle opening upper limit value is determined based on the fuel efficiency optimum line. It is determined by an engine operating curve set on the higher engine torque side than the optimum line. In this way, the second throttle opening upper limit value can be determined with a sufficient margin with respect to the throttle opening when the engine is driven so that the operating point of the engine is on the fuel efficiency optimum line. it can. Therefore, there is an advantage that the engine can be easily driven so that the operating point of the engine is located on the fuel efficiency optimal line or in the vicinity of the fuel efficiency optimal line.

  Here, preferably, the first throttle opening upper limit value is determined to be larger as the accelerator opening is larger. The upper limit value of the first throttle opening is zero if the accelerator opening is zero, and the maximum throttle opening if the accelerator opening is the maximum value of the accelerator opening. For example, if the accelerator opening is 100%, the first throttle opening upper limit is also 100%.

  Preferably, the first throttle opening upper limit value is determined regardless of the engine rotational speed, while the second throttle opening upper limit value is determined to be larger as the engine rotational speed is higher. The Accordingly, the first throttle opening upper limit value is equal to or higher than the second throttle opening upper limit value on the low engine speed side at the boundary of the engine speed at which both throttle opening upper limit values are equal to each other, On the high engine speed side, the second throttle opening upper limit is equal to or higher than the first throttle opening upper limit.

  Preferably, (a) the engine is provided with an electronic throttle valve that is opened and closed by an actuator, and (b) the vehicle control device is configured such that the opening degree of the electronic throttle valve is the target throttle opening. The actuator is controlled so as to converge each time.

1 is a skeleton diagram of a vehicle drive device included in a vehicle to which the present invention is applied. It is the figure which illustrated the input / output signal with respect to the electronic controller which functions as a control apparatus for controlling the vehicle drive device of FIG. It is a functional block diagram for demonstrating the principal part of the control function with which the electronic control apparatus of FIG. 2 was equipped. FIG. 3 is a diagram showing a pedal upper limit throttle opening map which is a relationship experimentally set in advance between an accelerator opening and a pedal upper limit throttle opening, which is used in control executed by the electronic control unit of FIG. 2. It is a figure for demonstrating the determination method of the operating point upper limit throttle opening used by the control which the electronic controller of FIG. 2 performs. The relationship between the permitted upper limit throttle opening, the pedal upper limit throttle opening, and the operating point upper limit throttle opening used in the control executed by the electronic control unit of FIG. 2 is expressed in two-dimensional coordinates between the engine speed and the target throttle opening. FIG. 3 is a target throttle opening allowance map. It is a block diagram for demonstrating the process in which the target throttle opening determination means contained in the electronic controller of FIG. 2 determines a base target throttle opening. 3 is a flowchart for explaining a main part of a control operation of the electronic control device of FIG. 2, that is, a control operation for determining a target throttle opening based on an accelerator opening and a vehicle speed.

  Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.

  FIG. 1 is a skeleton diagram of a vehicle drive device 10 included in a vehicle 8 to which the present invention is applied. The vehicle drive device 10 is of a horizontal type and is suitably employed in an FF (front engine / front drive) type vehicle. As shown in FIG. 1, the vehicle drive device 10 includes an engine 12, a torque converter 14, a forward / reverse switching device 16, and a belt type continuously variable transmission (CVT) 18. The engine 12 outputs the crankshaft 13 of the engine 12, the torque converter 14 to the forward / reverse switching device 16, the input shaft 36, the belt-type continuously variable transmission 18 (hereinafter referred to as the continuously variable transmission 18), and the reduction gear device 20. To the differential gear device 22 and distributed to a pair of left and right drive wheels 24L, 24R (in particular, the drive wheels 24 if left and right are not distinguished).

  The engine 12 is a driving power source for the vehicle 8 and is composed of an internal combustion engine such as a gasoline engine or a diesel engine. An electronic throttle valve 39 for electrically controlling the intake air amount of the engine 12 is provided in the intake pipe 38 of the engine 12. The electronic control device 60 opens and closes the electronic throttle valve 39 by the throttle actuator 40 (throttle valve drive device 40), thereby adjusting the intake air amount of the engine 12. In short, throttle control is performed. For example, as the opening degree TA of the electronic throttle valve 80 (hereinafter referred to as the throttle opening degree TA) increases, the intake air amount of the engine 12 increases and the engine torque Te increases.

  The torque converter 14 is a fluid transmission device disposed between the engine 12 and the continuously variable transmission 18, and includes a pump impeller 14 p as an input rotating member connected to the crankshaft 13 of the engine 12, a turbine, A turbine impeller 14t as an output rotating member connected to the forward / reverse switching device 16 via a shaft 34 is provided, and power is transmitted via a fluid.

  The torque converter 14 includes a lockup clutch 26 between the pump impeller 14p and the turbine impeller 14t. The lock-up clutch 26 is a friction engagement device capable of directly connecting the pump impeller 14p and the turbine impeller 14t, and the hydraulic pressure supply is switched by a hydraulic control valve or the like of the hydraulic control circuit 84 (see FIG. 2). To be engaged or released. For example, if the lock-up clutch 26 is brought into a directly connected state (completely engaged state) by hydraulic control, the pump impeller 14p and the turbine impeller 14t are thereby integrally rotated. A mechanical oil pump 28 is connected to the pump impeller 14p. The oil pump 28 functions as a hydraulic pressure supply source in the vehicle drive device 10 and further supplies lubricating oil to each part.

  The forward / reverse switching device 16 is mainly composed of a double pinion type planetary gear device, the turbine shaft 34 of the torque converter 14 is integrally connected to the sun gear 16s, and the input shaft 36 of the continuously variable transmission 18 is a carrier. The carrier 16c and the sun gear 16s are selectively connected via the forward clutch C1, and the ring gear 16r is selectively fixed to the housing via the reverse brake B1. It has become. Both the forward clutch C1 and the reverse brake B1 are hydraulic friction engagement devices that are frictionally engaged by a hydraulic cylinder. In the forward / reverse switching device 16, the forward clutch C1 is completely engaged and the reverse brake B1 is released, so that the forward / reverse switching device 16 is integrally rotated, and the driving force in the forward direction is continuously variable. It is transmitted to the transmission 18 side. On the other hand, when the reverse brake B1 is fully engaged and the forward clutch C1 is released, the input shaft 36 is rotated in the reverse direction with respect to the turbine shaft 34, and there is no drive force in the reverse direction. It is transmitted to the step transmission 18 side. Further, when both the forward clutch C1 and the reverse brake B1 are released, the forward / reverse switching device 16 becomes neutral (interrupted state) for interrupting power transmission.

  The continuously variable transmission 18 includes an input-side variable pulley 42 having a variable effective diameter that is an input-side member provided on the input shaft 36, and an output having a variable effective diameter that is an output-side member provided on the output shaft 44. Side variable pulleys 46 and transmission belts 48 wound around these variable pulleys 42, 46, and power is transmitted through frictional forces between the variable pulleys 42, 46 and the transmission belt 48. Is called. The continuously variable transmission 18 constitutes a part of the power transmission path from the engine 12 to the drive wheel 24, and the gear ratio γ (= input shaft rotational speed Nin / output shaft rotational speed Nout) is continuously controlled by hydraulic control. It is an automatic transmission that can be changed to The speed ratio γ of the continuously variable transmission 18 is changed by changing the engagement groove diameter (effective diameter) of the transmission belt 48 by changing the V groove width of both the variable pulleys 42 and 46. The electronic control unit 60 determines a target speed ratio γ * according to a target speed ratio map set experimentally in advance based on the vehicle speed V and the accelerator pedal opening PA, and approaches the speed ratio γ to the target speed ratio γ *. Thus, the continuously variable transmission 18 is shifted. The input shaft rotational speed Nin is the rotational speed of the input shaft 36, and the output shaft rotational speed Nout is the rotational speed of the output shaft 44. The continuously variable transmission 18 corresponds to the automatic transmission according to the present invention.

  FIG. 2 is a diagram illustrating input / output signals for the electronic control device 60 that functions as a control device for controlling the vehicle drive device 10 of the present embodiment. The electronic control device 60 is configured to include a so-called microcomputer, and executes vehicle control related to the engine 12 and the continuously variable transmission 18 by performing signal processing according to a program stored in advance. The electronic control device 60 corresponds to the vehicle control device of the present invention.

  As shown in FIG. 2, the electronic control unit 60 includes an engine rotational speed sensor 62, a turbine rotational speed sensor 64, an input shaft rotational speed sensor 66, an output shaft rotational speed sensor 68, a throttle sensor 70, an accelerator opening sensor 72, and the like. Are connected, the rotational speed of the engine 12 (engine rotational speed) Ne, the rotational speed of the turbine shaft 34 (turbine rotational speed) Nt, the rotational speed of the input shaft 36 (input shaft rotational speed) Nin, and the rotation of the output shaft 44 Signals representing speed (output shaft rotational speed) Nout, throttle opening degree TA (unit:%, for example), accelerator opening degree PA (unit:%, for example), which is the depression amount of the accelerator pedal 74, are supplied. Yes. The turbine rotational speed Nt coincides with the input shaft rotational speed Nin during forward traveling with the forward clutch C1 fully engaged. Further, since the output shaft rotational speed Nout of the continuously variable transmission 18 corresponds to the vehicle speed V, the output shaft rotational speed sensor 68 also functions as a vehicle speed sensor.

  Various output signals are supplied from the electronic control device 60 to each device provided in the vehicle 8. For example, the electronic control device 60 outputs a command signal for performing output control of the engine 12 to the fuel injection device 80, the ignition device 82, and the throttle actuator 40 of the engine 12. In addition, a command signal for performing shift control of the continuously variable transmission 18 and belt clamping pressure control is output to a solenoid valve or the like included in the hydraulic control circuit 84. The hydraulic control circuit 84 is a solenoid valve that opens and closes the oil passage when excited by the electronic control device 60, a linear solenoid valve that performs hydraulic control, and opens and closes the oil passage according to the signal pressure output from these solenoid valves. It includes an on-off valve, a pressure regulating valve, and the like.

  By the way, the electronic control unit 60 of the present embodiment sequentially sets the target throttle opening TA *, which is the target value of the throttle opening TA, in order to adjust the output of the engine 12 according to the operation of the accelerator pedal 74 by the driver. Then, the throttle actuator 40 is controlled so that the throttle opening TA converges to the target throttle opening TA *. The main part of the control function for determining the target throttle opening degree TA * will be described with reference to FIG.

  FIG. 3 is a functional block diagram for explaining the main part of the control function provided in the electronic control unit 60. As shown in FIG. 3, the electronic control unit 60 includes a pedal upper limit throttle opening determining unit 90 as a pedal upper limit throttle opening determining unit and an operating point upper throttle opening determining unit as an operating point upper throttle opening determining unit. 92, an allowable upper limit throttle opening determining means 94 as an allowable upper limit throttle opening determining section, a target throttle opening determining means 96 as a target throttle opening determining section, and a drive control means 98 as a drive control section. Functionally equipped.

  In the present embodiment, as the upper limit value of the target throttle opening degree TA *, the pedal upper limit throttle opening degree ULTAP *, which is the first throttle opening upper limit value based on the accelerator opening degree PA, and the fuel efficiency optimum line Lef (see FIG. 5) The operating point upper limit throttle opening ULTAe *, which is the second throttle opening upper limit value based on the above, is calculated. The larger one of the throttle opening upper limit values ULTAp * and ULTAe * is finally adopted as the upper limit value of the target throttle opening TA *. The pedal upper limit throttle opening determining means 90 sequentially determines the pedal upper limit throttle opening ULTAp * among the two upper limit values ULTAp * and ULTAe * with respect to the target throttle opening TA *. Specifically, the pedal upper limit throttle opening determining means 90 sequentially detects the accelerator opening PA by means of the accelerator opening sensor 72, and based on the accelerator opening PA, the accelerator opening PA as shown in FIG. And the pedal upper limit throttle opening ULTAp * are sequentially calculated from the pedal upper limit throttle opening map which is a relationship experimentally set in advance. In the pedal upper limit throttle opening map shown in FIG. 4, the pedal upper limit throttle opening ULTAp * increases as the accelerator opening PA increases. That is, the pedal upper limit throttle opening ULTAp * is zero if the accelerator opening PA is zero, and the maximum throttle opening TA if the accelerator opening PA is the maximum value (= 100%) of the accelerator opening PA. Value (= 100%). Further, the pedal upper limit throttle opening map shown in FIG. 4 may be proportional to the relationship between the accelerator opening PA and the pedal upper limit throttle opening ULTAp *, but is non-linear in this embodiment. This pedal upper limit throttle opening map is experimentally set in advance so that, for example, the throttle opening TA that can achieve the vehicle acceleration expected by the driver who has depressed the accelerator pedal 74 is set to the pedal upper limit throttle opening ULTAp *. Has been. As can be seen from FIG. 4, the engine speed Ne is not included in the parameters for determining the pedal upper limit throttle opening ULTAPp *, and the pedal upper limit throttle opening ULTAp * is independent of the engine speed Ne. To be determined.

  The operating point upper limit throttle opening determining means 92 sequentially detects the engine rotational speed Ne by means of the engine rotational speed sensor 62, and the engine rotational speed Ne and the optimal fuel consumption line Lef of the engine 12 set experimentally in advance. Based on the above, the operating point upper limit throttle opening ULTAe * is determined sequentially. That is, the operating point upper limit throttle opening ULTAe * is determined in order to suppress fuel consumption deterioration and engine vibration. FIG. 5 is a diagram for explaining a method of determining the operating point upper limit throttle opening ULTAe *. In FIG. 5, the fuel efficiency optimal line Lef indicates, for example, the operating point (operating point) of the engine 12 at which the fuel consumption rate of the engine 12 becomes minimum under a predetermined engine output in the steady operation state of the engine 12. This curve is obtained by changing the output and is obtained experimentally. Further, as indicated by a solid line L1ef in FIG. 5, an engine operation curve different from the fuel efficiency optimum line Lef is experimentally set in advance. The engine operation curve represented by the solid line L1ef is set in accordance with a predetermined setting condition on the higher engine torque side than the fuel efficiency optimal line Lef with reference to the fuel efficiency optimal line Lef. For example, the engine operating curve represented by the solid line L1ef indicates that the operating point of the engine 12 (hereinafter referred to as the operating point of the engine 12) where the fuel consumption is deteriorated by a predetermined width (for example, 1%) as compared with the case where the engine 12 is driven at the operating point on the optimal fuel economy line Lef. May be formed as a series of engine operating points or engine operating points), or may be formed by shifting the fuel efficiency optimum line Lef to the high engine torque side by a predetermined torque width. Further, each of the plurality of broken lines LTAcon shown in FIG. 5 indicates the relationship between the engine rotational speed Ne and the engine torque Te under a certain throttle opening TA, and is represented by a broken line LTAcon on the high engine torque side. The more the throttle opening TA corresponding to the broken line LTAcon becomes, the more it becomes.

  In FIG. 5, for example, when the engine operating curve represented by the solid line L1ef is used, the engine torque Te as the vertical axis is determined if the engine rotational speed Ne as the horizontal axis is given, but a plurality of broken lines LTAcon are shown in FIG. As is clear from the above, the throttle opening degree TA is also determined from the engine operating curve represented by the solid line L1ef and the broken line LTAcon. Therefore, the operating point upper limit throttle opening determining means 92 is based on the fuel efficiency optimum line Lef, specifically, on the basis of the engine operating curve represented by the solid line L1ef with the fuel efficiency optimum line Lef as a reference, and the engine speed. Based on the speed Ne, the throttle opening degree TA indicated by the engine operation curve (solid line L1ef) is obtained, and the obtained throttle opening degree TA is determined as the operating point upper limit throttle opening degree ULTAe *.

  The permitted upper limit throttle opening determining means 94 obtains the pedal upper limit throttle opening ULTAp * from the pedal upper limit throttle opening determining means 90 and obtains the operating point upper limit throttle opening ULTAe * from the operating point upper limit throttle opening determining means 92. get. Then, the pedal upper limit throttle opening ULTAp * and the operating point upper limit throttle opening ULTAe * are compared with each other, and the larger of the upper limit throttle opening ULTAp * and ULTAe * is determined as the target throttle opening TA *. Is determined as the final upper limit value, that is, the permitted upper limit throttle opening ULTA *. For example, if the pedal upper limit throttle opening ULTAp * is larger than the operating point upper limit throttle opening ULTAe *, the permitted upper limit throttle opening determining means 94 sets the pedal upper limit throttle opening ULTAp * to the permitted upper limit throttle opening ULTA *. And On the other hand, if the pedal upper limit throttle opening ULTAp * is equal to or less than the operating point upper limit throttle opening ULTAe *, the permitted upper limit throttle opening determining means 94 sets the operating point upper limit throttle opening ULTAe * to the permitted upper limit throttle opening ULTAe *. *

  FIG. 6 shows the relationship between the permitted upper limit throttle opening ULTA *, the pedal upper limit throttle opening ULTAp *, and the operating point upper limit throttle opening ULTAe * in two-dimensional coordinates between the engine speed Ne and the target throttle opening TA *. It is the figure shown, ie, a target throttle opening allowable map. FIG. 6 is a target throttle opening allowable map when the accelerator opening PA is a certain size. In FIG. 6, the broken line L01 indicates the pedal upper limit throttle opening ULTAp *, the broken line L02 indicates the operating point upper limit throttle opening ULTAe *, and the solid line L03 indicates the permitted upper limit throttle opening ULTA *. It is. The solid line Lef in FIG. 6 represents the optimum fuel efficiency line Lef shown in FIG. 5 in the coordinate system shown in FIG. 6 by assuming that the throttle opening degree TA coincides with the target throttle opening degree TA *. In FIG. 6, the solid line L03 overlaps with the broken line L01 or the broken line L02, but is deviated and displayed for easy viewing.

  As can be seen from the broken line L01 in FIG. 6, the pedal upper limit throttle opening ULTAp * is constant regardless of the engine speed Ne as long as the accelerator opening PA is constant. On the other hand, the operating point upper limit throttle opening ULTAe * is determined to be larger as the engine speed Ne is higher, as indicated by the broken line L02. Accordingly, the pedal upper limit throttle opening ULTAp on the lower engine speed side than the engine speed Neb at the boundary of the engine speed Ne (Neb in FIG. 6) where both the upper limit throttle openings ULTAp * and ULTAe * are equal to each other. * Exceeds the operating point upper limit throttle opening ULTAe *. That is, the pedal upper limit throttle opening ULTAp * is set to the permitted upper limit throttle opening ULTA *. On the other hand, the operating point upper limit throttle opening ULTAe * is equal to or higher than the pedal upper limit throttle opening ULTAp * on the higher engine rotation speed side than the engine rotation speed Neb. That is, the operating point upper limit throttle opening ULTAe * is set as the permitted upper limit throttle opening ULTA *. Then, the target throttle opening degree TA * can take a value within a range equal to or smaller than the allowable upper limit throttle opening degree ULTA * indicated by a solid line L03, that is, a value within a range indicated by a region A01 in FIG.

  The target throttle opening determining means 96 sequentially determines the target throttle opening TA *. However, the permitted upper limit throttle opening ULTA * is sequentially obtained from the permitted upper limit throttle opening determining means 94, and the target throttle opening TA * is limited to be equal to or lower than the permitted upper limit throttle opening ULTA *. For this purpose, the target throttle opening degree determining means 96 first determines a base target throttle opening degree TAb * corresponding to the target throttle opening degree TA * that is not limited by the permitted upper limit throttle opening degree ULTA *. A process of determining the base target throttle opening degree TAb * is shown in FIG.

  FIG. 7 is a block diagram for explaining a process in which the target throttle opening degree determining means 96 determines the base target throttle opening degree TAb *. The target throttle opening degree determining means 96 sequentially detects the vehicle speed V by the output shaft rotational speed sensor 68 and sequentially detects the accelerator opening degree PA by the accelerator opening degree sensor 72. Then, as shown in FIG. 7, based on the vehicle speed V and the accelerator pedal opening PA, the target driving force Fc *, which is the target value of the driving force Fc of the vehicle 8, and the speed ratio γ of the continuously variable transmission 18 are determined. A target speed ratio γ *, which is a target value, is determined. For example, the target driving force Fc * is determined from a relationship that is experimentally set in advance so that the driving force Fc expected by the driver who has depressed the accelerator pedal 74 is generated, that is, the target driving force map. The target transmission ratio γ * of the continuously variable transmission 18 is such that the fuel consumption rate of the engine 12 is as much as possible when the engine 12 generates engine output (unit: kW, for example) that provides the target driving force Fc *. It is determined from a relationship experimentally set in advance so as to decrease, that is, a target gear ratio map. For example, the target gear ratio map is a generally known map, and is set such that the target gear ratio γ * increases as the vehicle speed V decreases or the accelerator pedal opening degree PA increases. Since the target throttle opening determining means 96 determines the target speed ratio γ * as described above, it can be said that the target throttle opening degree determining means 96 also functions as the target speed ratio determining means.

  The target throttle opening determining means 96, when determining the target driving force Fc * and the target gear ratio γ *, is the target value of the engine torque Te based on the target driving force Fc * and the target gear ratio γ *. A target engine torque Te * is calculated. The target engine torque Te * is the engine torque Te corresponding to the target driving force Fc * when the speed ratio γ of the continuously variable transmission 18 is the target speed ratio γ *. In other words, the target engine torque Te * is calculated by converting the target driving force Fc * into the engine torque Te in consideration of the target speed ratio γ * and the diameter of the driving wheel 24. Further, the target throttle opening determining means 96 calculates a target engine speed Ne * that is a target value of the engine speed Ne based on the vehicle speed V and the target speed ratio γ *. The target engine speed Ne * is the engine speed Ne corresponding to the vehicle speed V when the speed ratio γ of the continuously variable transmission 18 is the target speed ratio γ *. In other words, the target engine speed Ne * is calculated by converting the vehicle speed V into the engine speed Ne taking into account the target gear ratio γ *, the diameter of the drive wheels 24, and the like.

  When the target throttle opening degree determining means 96 calculates the target engine speed Ne * and the target engine torque Te *, the base target throttle opening degree TAb * is calculated based on the target engine speed Ne * and the target engine torque Te *. To decide. More specifically, a generally known engine drive characteristic that is a relationship between the engine rotational speed Ne and the engine torque Te according to the throttle opening degree TA is experimentally obtained in advance, and the target throttle opening degree determination is performed. The means 96 gives the target engine speed Ne * and the target engine torque Te * to the engine drive characteristics as the engine speed Ne and engine torque Te, respectively, and sets the throttle opening TA obtained from the engine drive characteristics as the base target throttle. Determine as opening TAb *. On the condition that this base target throttle opening degree TAb * is equal to or smaller than the allowable upper limit throttle opening degree ULTA *, it is used as it is as the target throttle opening degree TA * for driving control of the engine 12. The target speed ratio γ * is used for speed change control of the continuously variable transmission 18 (T / M).

  When the target throttle opening degree determining means 96 determines the base target throttle opening degree TAb * as described with reference to FIG. 7, the base target throttle opening degree TAb * and the allowable upper limit throttle opening degree ULTA * are compared with each other. The smaller one of the base target throttle opening degree TAb * and the permitted upper limit throttle opening degree ULTA * is determined as the target throttle opening degree TA *. In this way, the target throttle opening degree determining means 96 limits the target throttle opening degree TA * to the allowable upper limit throttle opening degree ULTA * or less.

  The drive control means 98 performs drive control of the engine 12 and shift control of the continuously variable transmission 18. For example, in the drive control of the engine 12, the drive control means 98 sequentially acquires the target throttle opening degree TA * from the target throttle opening degree determination means 96, and the throttle opening degree TA detected by the throttle sensor 70 becomes the target throttle opening degree. The throttle actuator 40 is controlled to converge to the degree TA *. Specifically, the difference (deviation) between the throttle opening TA and the target throttle opening TA * is sequentially calculated, and feedback control is performed to operate the throttle actuator 40 so that the difference approaches zero.

  Further, the drive control means 98 sequentially acquires the target speed ratio γ * from the target throttle opening degree determining means (target speed ratio determining means) 96 and the input shaft rotational speed sensor 66 in the speed change control of the continuously variable transmission 18. The speed ratio γ of the continuously variable transmission 18 is sequentially calculated based on the input shaft rotational speed Nin detected by the output shaft and the output shaft rotational speed Nout detected by the output shaft rotational speed sensor 68. The hydraulic control circuit 84 is instructed to control the effective diameter of the input side variable pulley 42 and the effective diameter of the output side variable pulley 46 so that the speed ratio γ converges to the target speed ratio γ *. By performing the drive control of the engine 12 and the shift control of the continuously variable transmission 18 in this manner, the engine 12 and the continuously variable transmission 18 are operated so as to obtain the target drive force Fc * efficiently.

  FIG. 8 is a flowchart for explaining a main part of the control operation of the electronic control unit 60, that is, a control operation for determining the target throttle opening degree TA * based on the accelerator opening degree PA and the vehicle speed V, for example, several msec. It is repeatedly executed with an extremely short cycle time of about several tens of milliseconds. The control operation shown in FIG. 8 is executed alone or in parallel with other control operations.

  First, in a step (hereinafter, “step” is omitted) SA1 corresponding to the pedal upper limit throttle opening determining means 90 and the target throttle opening determining means 96, the current accelerator opening PA is detected by the accelerator opening sensor 72. Is done. In other words, the accelerator opening PA is determined based on the signal obtained from the accelerator opening sensor 72. At this time, the accelerator opening PA may be determined in a non-linear relationship with respect to the operation angle of the accelerator pedal 74 or may be determined in a linear relationship. In SA1, the current vehicle speed V is detected by the output shaft rotation speed sensor (vehicle speed sensor) 68. After SA1, the process proceeds to SA2.

  In SA2 corresponding to the target throttle opening determining means 96, as shown in FIG. 7, the target driving force Fc * and the target speed ratio γ * of the continuously variable transmission 18 are determined based on the vehicle speed V detected in SA1 and the vehicle speed V. It is calculated based on the accelerator opening PA. Then, the base target throttle opening degree TAb * is calculated based on the target driving force Fc * and the target gear ratio γ *. For example, since the driver depresses the accelerator pedal 74 as the driving force is increased, the target driving force Fc * increases as the accelerator opening degree PA increases. After SA2, the process proceeds to SA3.

  In SA3 corresponding to the pedal upper limit throttle opening determining means 90, the pedal upper limit throttle opening ULTAPp * is calculated from the pedal upper limit throttle opening map of FIG. 4 based on the accelerator opening PA detected in SA1. The After SA3, the process proceeds to SA4.

  In SA4 corresponding to the operating point upper limit throttle opening determining means 92, the engine speed Ne is detected by the engine speed sensor 62, and the operating point upper limit throttle opening ULTAe * is calculated based on the engine speed Ne. It is calculated from the engine operating curve represented by the solid line L1ef of 5. After SA4, the process proceeds to SA5.

  In SA5, it is determined whether or not the pedal upper limit throttle opening ULTAp * is larger than the operating point upper limit throttle opening ULTAe *. If the determination of SA5 is affirmative, that is, if the pedal upper limit throttle opening ULTAp * is larger than the operating point upper limit throttle opening ULTAe *, the process proceeds to SA6. On the other hand, if the determination at SA5 is negative, the operation goes to SA7.

  In SA6, the permitted upper limit throttle opening ULTA * is set to the pedal upper limit throttle opening ULTAp *. After SA6, the process proceeds to SA8.

  In SA7, the permitted upper limit throttle opening ULTA * is set to the operating point upper limit throttle opening ULTAe *. After SA7, the process proceeds to SA8. SA5 to SA7 correspond to the permitted upper limit throttle opening determining means 94.

  In SA8 corresponding to the target throttle opening determining means 96, the smaller of the base target throttle opening TAb * and the permitted upper limit throttle opening ULTA * is determined as the target throttle opening TA *. In this way, the target throttle opening degree TA * is limited to the allowable upper limit throttle opening degree ULTA * or less at SA8.

  According to this embodiment, as shown in FIG. 7, the electronic control unit 60 sets the target throttle opening degree TA * of the engine 12 based on the target driving force Fc * and the target speed ratio γ * of the continuously variable transmission 18. To decide. Then, the pedal upper limit throttle opening ULTAPp * (first throttle opening upper limit value) determined based on the accelerator opening PA and the fuel consumption optimum line Lef (see FIGS. 5 and 6) set in advance for the engine 12 The target throttle opening TA * is less than or equal to the larger upper limit throttle opening (throttle opening upper limit) of the operating point upper limit throttle opening ULTAe * (second throttle opening upper limit) determined based on Restrict. Accordingly, since the target throttle opening degree TA * is allowed to be at least up to the pedal upper limit throttle opening degree ULTAp *, there is an advantage that the driver's accelerator operation can be easily reflected in the drive of the engine 12 immediately. Further, when the operating point upper limit throttle opening ULTAe * exceeds the pedal upper limit throttle opening ULTAp *, the target throttle opening TA * is limited by the operating point upper limit throttle opening ULTAe *. Is greatly deviated from the fuel efficiency optimum line Lef. In short, by using the pedal upper limit throttle opening ULTAp * or the operating point upper limit throttle opening ULTAe *, the driver's accelerator operation is reflected in the driving of the engine 12, and the fuel consumption deterioration of the engine 12 can be suppressed. For example, when the change in hydraulic pressure for executing the shift control of the continuously variable transmission 18 is delayed with respect to the depression operation of the accelerator pedal 74, the engine torque Te can be compensated for the delay in the hydraulic pressure change. Thereby, good responsiveness is ensured. Further, the target throttle opening degree TA * can exceed the pedal upper limit throttle opening degree ULTAp * as long as the operating point upper limit throttle opening degree ULTAe * allows, so that even when the accelerator pedal 74 is further depressed, Good response is ensured while reflecting the driver's intention. If the pedal upper limit throttle opening ULTAp * exceeds the operating point upper limit throttle opening ULTAe *, the target throttle opening TA * will be within the range of the pedal upper limit throttle opening ULTAp * or less. Although it may exceed ULTAe *, there is no particular problem because the intention to accelerate is more important than the fuel efficiency when the driver greatly depresses the accelerator pedal 74.

  Further, according to the present embodiment, the automatic transmission included in the vehicle drive device 10 is the continuously variable transmission 18. Therefore, compared with the case where the automatic transmission is a stepped transmission, there is an advantage that the engine 12 can be easily driven in accordance with the optimum fuel consumption line Lef.

  Further, according to the present embodiment, as shown in FIG. 5, the operating point upper limit throttle opening ULTAe * is determined based on the fuel efficiency optimum line Lef as the engine operation set on the higher engine torque side than the fuel efficiency optimum line Lef. Determined by curve (solid line L1ef). Therefore, the operating point upper limit throttle opening ULTAe * can be determined with a sufficient margin with respect to the throttle opening TA when the engine 12 is driven so that the operating point of the engine 12 is on the fuel efficiency optimum line Lef. . Therefore, there is an advantage that the engine 12 can be easily driven so that the operating point of the engine 12 is located on or near the fuel efficiency optimal line Lef.

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

  For example, in the above-described embodiment, the vehicle drive device 10 includes the torque converter 14, but may be configured without the torque converter 14.

  In the above-described embodiment, the vehicle drive device 10 includes the continuously variable transmission 18 as an automatic transmission. For example, the continuously variable transmission 18 is not a belt type but a toroidal cone type continuously variable transmission. It doesn't matter.

  In the above-described embodiment, the operating point upper limit throttle opening ULTAe * is determined from the engine operating curve represented by the solid line L1ef (see FIG. 5) with the fuel efficiency optimal line Lef as a reference. It is also conceivable to be determined from other engine operating curves set with reference to the line Lef. For example, the operating point upper limit throttle opening ULTAe * may be determined from the fuel efficiency optimum line Lef itself.

  In the above-described embodiment, the control operation shown in the flowchart of FIG. 8 is preferably executed when the lockup clutch 26 is in the engaged state, but is executed when the lockup clutch 26 is in the released state. May be.

  In the above-described embodiment, the engine rotational speed Ne is adopted for the horizontal axis of FIGS. 5 and 6, but the parameter of the horizontal axis can be replaced with the vehicle speed V from the engine rotational speed Ne.

8: Vehicle 10: Vehicle drive device 12: Engine 18: Belt type continuously variable transmission (automatic transmission)
24L, 24R: Driving wheel 60: Electronic control device (vehicle control device)

Claims (3)

In a vehicle including an engine and an automatic transmission that transmits the power of the engine to driving wheels, the target throttle opening of the engine is determined based on a target driving force and a target gear ratio of the automatic transmission. A control device,
The larger throttle opening of the first throttle opening upper limit determined based on the accelerator opening and the second throttle opening upper limit determined based on the preset fuel efficiency optimum line of the engine The vehicle control apparatus, wherein the target throttle opening is limited to an upper limit value or less. The vehicular control device according to claim 1, wherein the automatic transmission is a continuously variable transmission. The second throttle opening upper limit value is determined by an engine operation curve set on a higher engine torque side than the fuel efficiency optimal line with the fuel efficiency optimal line as a reference. The vehicle control device described.

Images