JP2009210045A - Vehicle travel control device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a vehicle travel control device in a vehicle where an internal combustion engine and a continuously variable transmission for transmitting the output of the internal combustion engine to a driving shaft are mounted, for controlling the internal combustion engine and the continuously variable transmission to actualize a target revolving speed as a target value for the revolving speed of the internal combustion engine, while giving a driver a feel of acceleration corresponding to a change of a vehicle speed during acceleration. <P>SOLUTION: The vehicle travel control device is provided in the vehicle where the internal combustion engine and the continuously variable transmission for transmitting the output of the internal combustion engine to the driving shaft are mounted, for controlling the internal combustion engine and the continuously variable transmission to actualize the target revolving speed as the target value for the revolving speed of the internal combustion engine. It comprises a setting means for setting the target revolving speed in accordance with the vehicle speed, and a determining means for determining whether the vehicle is in an accelerated condition or not. The setting means sets the target revolving speed so that an increment in the sound pressure of the internal combustion engine is proportional to an increment of the vehicle speed (S70, S80), when the determining means determines that the vehicle is in the accelerated condition (S40-Y). <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a vehicle travel control device, and in particular, is provided in a vehicle on which an internal combustion engine and a continuously variable transmission that transmits the output of the internal combustion engine to a drive shaft are mounted, and is a target value for the rotational speed of the internal combustion engine. The present invention relates to a vehicle travel control device that controls an internal combustion engine and a continuously variable transmission to achieve a target rotational speed.

  In a vehicle equipped with an internal combustion engine and a continuously variable transmission that transmits the output of the internal combustion engine to a drive shaft, the internal combustion engine and the continuously variable transmission are realized so as to achieve a target rotational speed that is a target value of the rotational speed of the internal combustion engine. When the aircraft is controlled, the driver may feel uncomfortable with the acceleration feeling obtained during acceleration. The feeling of acceleration felt by the driver differs depending not only on the actual vehicle speed change but also on the engine sound and the like. For this reason, depending on the control mode of the internal combustion engine and the continuously variable transmission, there is a case where a sufficient feeling of acceleration cannot be obtained even though the vehicle is accelerating.

  In Patent Document 1, in a vehicle in which the increase in the speed of the vehicle and the increase in the engine speed of the internal combustion engine are not proportionally linked during acceleration, the internal combustion engine is controlled based on the increase in the speed of the vehicle regardless of the fluctuation in the engine speed. An engine sound emphasizing device including engine sound adjusting means for increasing engine sound is disclosed. According to this engine sound emphasizing device, the driver of the vehicle can obtain an acceleration feeling even when the increase in the vehicle speed and the increase in the engine rotation speed of the internal combustion engine are not proportionally linked.

JP 2006-83818 A

  When the engine noise is increased based on the increase in the speed of the vehicle regardless of the fluctuation of the engine rotation speed as in Patent Document 1, the acceleration feeling obtained by the engine rotation speed region may fluctuate. The magnitude of the fluctuation of the engine sound (sound pressure) with respect to the fluctuation of the engine rotation speed varies depending on the engine rotation speed region. For this reason, in the engine sound emphasizing device of the above-mentioned Patent Document 1, for example, the engine sound may be felt noisy in an engine rotation speed region where the engine sound greatly increases with respect to fluctuations in the engine rotation speed. On the other hand, there is a possibility that a feeling of stagnation is felt in acceleration in a region where the engine speed is small with respect to fluctuations in engine speed.

  In a vehicle equipped with an internal combustion engine and a continuously variable transmission that transmits the output of the internal combustion engine to a drive shaft, the internal combustion engine and the continuously variable transmission are realized so as to achieve a target rotational speed that is a target value of the rotational speed of the internal combustion engine. When a machine is controlled, it is desired to give the driver a feeling of acceleration corresponding to a change in vehicle speed during acceleration.

  An object of the present invention is provided in a vehicle equipped with an internal combustion engine and a continuously variable transmission that transmits the output of the internal combustion engine to a drive shaft, and realizes a target rotational speed that is a target value of the rotational speed of the internal combustion engine. Thus, in a vehicle travel control device that controls an internal combustion engine and a continuously variable transmission, it is an object to provide a vehicle travel control device that can give the driver a feeling of acceleration corresponding to a change in vehicle speed during acceleration.

  The vehicle travel control device of the present invention is provided in a vehicle on which an internal combustion engine and a continuously variable transmission that transmits the output of the internal combustion engine to a drive shaft are mounted, and is a target that is a target value of the rotational speed of the internal combustion engine. A vehicle travel control device for controlling the internal combustion engine and the continuously variable transmission so as to realize a rotational speed, wherein the setting means for setting the target rotational speed based on a vehicle speed, and the vehicle is in an acceleration state Determining means for determining whether or not the sound pressure of the internal combustion engine with respect to the increase amount of the vehicle speed when the determining means determines that the vehicle is in an acceleration state. The target rotational speed is set so that the amount of increase is proportional.

  In the vehicle travel control device of the present invention, the setting means increases the target rotational speed as the vehicle speed increases, and the rotation with a small increase in the sound pressure with respect to the increase in the rotational speed is performed. In the number region, the amount of increase in the target number of rotations relative to the amount of increase in the vehicle speed is increased compared to the region of number of rotations where the amount of increase in the sound pressure is large relative to the amount of increase in the number of rotations. To do.

  The vehicle travel control apparatus according to the present invention is characterized in that the target rotational speed is realized by changing the rotational speed by shift control of the continuously variable transmission.

  According to the present invention, in a vehicle equipped with an internal combustion engine and a continuously variable transmission that transmits the output of the internal combustion engine to a drive shaft, a target rotational speed that is a target value of the rotational speed of the internal combustion engine is realized. When controlling the internal combustion engine and the continuously variable transmission, if it is determined that the vehicle is in an acceleration state, the increase amount of the sound pressure of the internal combustion engine is proportional to the increase amount of the vehicle speed. The target rotational speed is set. As a result, it is possible to give the driver a feeling of acceleration corresponding to changes in the vehicle speed.

  Hereinafter, an embodiment of a vehicle travel control device of the present invention will be described in detail with reference to the drawings.

(First embodiment)
The first embodiment will be described with reference to FIGS. 1 to 11. The present embodiment is provided in a vehicle on which an internal combustion engine and a continuously variable transmission that transmits the output of the internal combustion engine to a drive shaft are mounted, and achieves a target rotational speed that is a target value of the rotational speed of the internal combustion engine. In particular, the present invention relates to a vehicle travel control device that controls an internal combustion engine and a continuously variable transmission.

  In this embodiment, in a vehicle equipped with an engine (internal combustion engine) and a continuously variable transmission that transmits the output of the engine to a drive shaft, a target engine rotational speed (target rotational speed) that is a target value of the rotational speed of the engine. ) Is controlled so that the engine and the continuously variable transmission are realized. At the time of acceleration, the acceleration linear feeling is improved by controlling the target engine speed according to the sound pressure characteristic of the engine.

  More specifically, based on the control that fluctuates the target engine speed in proportion to the vehicle speed, the gear ratio is set to a lower speed in a region where the increase in engine sound pressure with respect to the increase in engine speed is low. To do. That is, in the region of the engine rotation speed where the increase in engine sound pressure is moderate and the driver does not feel acceleration feeling, the increase in engine rotation speed is promoted. Thereby, the rising speed of the engine sound pressure is increased, and it is suppressed that the driver and the passenger feel a stagnation feeling of the engine rotation increase during acceleration.

  On the other hand, in a region where the increase in engine sound pressure is high with respect to the increase in engine rotation speed, the gear ratio is set to a higher speed side. That is, in the engine rotation speed region where the engine sound pressure increases rapidly and the driver feels that the engine sound is noisy, the increase in the engine rotation speed is moderated. Thereby, the rising speed of the engine sound pressure can be suppressed and noise can be reduced.

The configuration of the present embodiment is premised on the following configurations (1) to (4).
(1) Internal combustion engine (2) Continuously variable transmission (CVT, continuously variable transmission (continuously variable transmission mechanism) provided in HV vehicles)
(3) Driving force control device (4) Accelerator pedal and accelerator pedal opening sensor

  FIG. 1 is a block diagram according to the driving force control of the present embodiment.

  In FIG. 1, reference numeral 1 denotes an engine (internal combustion engine). The output torque of the engine 1 is transmitted to the continuously variable transmission 2. The continuously variable transmission 2 controls the gear ratio steplessly (continuously), and transmits the output of the engine 1 to a drive shaft (not shown). An output shaft (not shown) of the engine 1 is configured to be connectable to an input shaft (not shown) of the continuously variable transmission 2, and the input rotational speed (input shaft rotational speed) of the continuously variable transmission 2 is This corresponds to the engine rotation speed (output shaft rotation speed) which is the rotation speed of the engine 1. Note that the vehicle travel control device according to the present embodiment is capable of controlling the input rotational speed (engine rotational speed) of the continuously variable transmission 2 according to the vehicle speed, such as a continuously variable transmission (continuously variable transmission mechanism) of a CVT or HV vehicle. The present invention can be applied to various continuously variable transmissions in which a target value is set.

  A vehicle (not shown) on which the engine 1 and the continuously variable transmission 2 are mounted is provided with a vehicle travel control device 100 that controls the vehicle. The vehicle travel control device 100 controls the engine 1 and the continuously variable transmission 2 so as to realize a target engine rotation speed that is a target value of the engine rotation speed. More specifically, the vehicle travel control apparatus 100 calculates a target engine rotation speed based on the target driving force, and sets the target input rotation speed of the continuously variable transmission 2 so as to realize the calculated target engine rotation speed. Set. The vehicle travel control device 100 executes operation control of the engine 1 based on the target engine rotational speed and the target engine torque set corresponding to the target engine rotational speed, and the continuously variable transmission 2 of the continuously variable transmission 2 based on the target input rotational speed. Shift control is executed.

  The vehicle travel control device 100 includes a target driving force calculation unit 10, a control amount calculation unit 20, and a control unit 30. The vehicle travel control device 100 is configured by a well-known microcomputer and includes a CPU, a RAM, a ROM, an input port, an output port, and a common bus (not shown). The vehicle travel control device 100 of this embodiment has a function as a determination unit.

  The target driving force calculation unit 10 calculates a target driving force Ftgt based on the accelerator opening (accelerator operation amount) accp and the vehicle speed spd. Accelerator opening degree detection means 3 and vehicle speed detection means 4 are connected to the target driving force calculation unit 10. The accelerator opening detecting means 3 detects an accelerator operation amount that is a driver's operation amount for an accelerator (not shown). The accelerator is not limited to a so-called accelerator pedal, but an operating device that instructs the vehicle on the acceleration (driving force) required by the driver. Based on the accelerator operation amount, the magnitude of the driver's acceleration request is detected (estimated). The accelerator opening degree detecting means 3 detects an accelerator opening degree accp [%] in which the accelerator opening degree when the accelerator is fully opened is 100%, and outputs a signal corresponding to the detection result to the target driving force calculation unit 10. To do. The target driving force calculation unit 10 detects the accelerator opening degree accp based on the signal acquired from the accelerator opening degree detection means 3.

  The vehicle speed detection means 4 detects a vehicle speed spd that is the speed of the vehicle. The vehicle speed detection means 4 detects, for example, the rotation speed of the output shaft of the continuously variable transmission 2 that is proportional to the vehicle speed spd, and outputs a signal corresponding to the detection result to the target driving force calculation unit 10. The target driving force calculation unit 10 detects the vehicle speed spd based on the signal acquired from the vehicle speed detection means 4.

  The target driving force calculation unit 10 calculates the target driving force Ftgt with reference to the map shown in FIG. 2 based on the detected accelerator opening degree accp and the vehicle speed spd. In FIG. 2, the horizontal axis represents the vehicle speed spd, and the vertical axis represents the driving force force. Symbols accp1, accp2, and accp3 are curves showing the relationship between the vehicle speed spd and the target driving force Ftgt according to the accelerator opening degree accp. The accelerator opening degree accp has a large value in the order of accp1 to accp3. As shown in FIG. 2, the target driving force Ftgt is calculated as a larger value as the accelerator opening degree accp becomes larger with respect to a predetermined vehicle speed spd. The target driving force calculation unit 10 outputs the calculated target driving force Ftgt and the vehicle speed spd to the control amount calculation unit 20.

  As shown in FIG. 1, the control amount calculation unit 20 includes a target output calculation unit 21 and a target control amount calculation unit (setting unit) 22. The target output calculation unit 21 calculates the target power (target output) P of the engine 1 based on the target driving force Ftgt and the vehicle speed spd acquired from the target driving force calculation unit 10. The target output calculation unit 21 calculates the target power P by multiplying the target driving force Ftgt and the vehicle speed spd.

  The target control amount calculation unit 22 calculates a target control amount based on the target power P calculated by the target output calculation unit 21. Here, the target control amounts are a target engine speed nintgt that is a target value of the engine speed NIN and a target engine torque trqtgt that is a target value of the output torque TE of the engine 1. As described above, the input rotational speed (input shaft rotational speed) of the continuously variable transmission 2 corresponds to the engine rotational speed (output shaft rotational speed) NIN. Accordingly, the target speed ratio of the continuously variable transmission 2 is set in correspondence with the target engine speed nintgt.

  As shown in FIG. 1, the calculated target engine speed nintgt and target engine torque trqtgt are output from the target control amount calculation unit 22 to the control unit 30. The control unit 30 functions as an operation control unit that performs operation control of the engine 1 and a shift control unit that performs shift control of the continuously variable transmission 2. The control unit 30 is connected to the engine 1, and a command value for controlling the operation state of the engine 1 is output from the control unit 30 to the engine 1. The control unit 30 controls the engine 1 so as to realize the target engine rotation speed nintgt and the target engine torque trqtgt. The control unit 30 is connected to the continuously variable transmission 2, and a signal indicating a target value (target gear ratio) of the gear ratio is output from the control unit 30 to the continuously variable transmission 2. The control unit 30 determines the target gear ratio of the continuously variable transmission 2 so that the engine rotational speed NIN (input rotational speed of the continuously variable transmission 2) becomes the target engine rotational speed nintgt. The continuously variable transmission 2 performs a shift according to the target gear ratio acquired from the control unit 30.

  The target control amount calculation unit 22 of the present embodiment basically makes the target engine speed nintgt proportional to the vehicle speed spd. That is, the target engine rotational speed nintgt is proportionally increased as the vehicle speed spd increases. This suppresses the driver from feeling uncomfortable with the engine sound during acceleration, as will be described below.

  During acceleration, although the vehicle speed spd increased, the engine speed NIN did not increase, or even if the engine speed NIN increased, the increase amount was not proportional to the increase in the vehicle speed spd. In this case, the driver may not feel an acceleration according to the change in the vehicle speed spd and may feel uncomfortable with the engine sound. On the other hand, by making the target engine speed nintgt proportional to the vehicle speed spd basically, it is possible to suppress the driver from feeling uncomfortable during acceleration.

  However, although the engine speed NIN increases in proportion to the vehicle speed spd, the engine sound pressure that is the sound pressure of the engine sound does not increase depending on the region of the engine speed NIN, and there is a feeling of stickiness. On the contrary, there is a problem that the engine sound pressure suddenly increases and the engine sound is felt noisy. This is because the engine rotational speed NIN and the engine sound pressure are in a non-linear relationship, as will be described below with reference to FIGS.

  FIG. 3 is a diagram showing an example of the relationship between the engine speed NIN and the engine sound pressure. FIG. 3 shows the engine sound pressure detected in the passenger compartment. Here, the engine sound is a sound generated with the operation of the engine 1 such as a combustion sound generated in the main body of the engine 1 or an exhaust sound generated in an exhaust passage (not shown) of the engine 1. The sound pressure when the sound generated during the operation of the engine 1 is detected in the passenger compartment is the engine sound pressure shown in FIG. In other words, the engine sound pressure is the volume of sound generated by the operation of the engine 1 that is actually felt by the driver (passenger).

  Reference numeral 101 (solid line) indicates an actually measured value of the engine sound pressure, and reference numeral 102 (broken line) indicates a calculated value of the engine sound pressure. The engine rotational speed NIN and the engine sound pressure 101, 102 are in a non-linear relationship, and as indicated by the symbol R1, the increase in the engine sound pressure 101, 102 is moderate or hardly increased with the increase in the engine rotational speed NIN. On the other hand, there is a region where the engine sound pressures 101 and 102 increase greatly as the engine rotational speed NIN increases, as indicated by reference numeral R2. For this reason, as will be described with reference to FIG. 4, depending on the acceleration condition, a phenomenon has occurred in which the engine sound pressure 101 does not increase so much or the engine sound pressure 101 increases excessively.

  FIG. 4 is a diagram illustrating an example of a temporal transition of the engine rotation speed NIN and the engine sound pressure 101 during acceleration. In FIG. 4, the horizontal axis represents time, and the vertical axis represents engine rotational speed NIN and engine sound pressure. When shift control of the continuously variable transmission 2 is performed in which the engine rotation speed NIN is uniformly proportional to the vehicle speed spd during acceleration, the increase in the engine sound pressure 101 as indicated by the symbol R3 or the phenomenon indicated by the symbol R4 The engine sound pressure 101 is excessively increased.

  In the present embodiment, as will be described below with reference to FIGS. 5 to 7, the target engine speed nintgt is corrected so that the increase amount of the engine sound pressure is proportional to the increase amount of the vehicle speed spd. Is done. As a result, it is possible to suppress an increase in the engine sound pressure from stagnation or an excessive increase in the engine sound pressure with respect to the increase in the vehicle speed spd during acceleration.

  Here, the increase amount of the engine sound pressure is proportional to the increase amount of the vehicle speed spd, for example, the relationship between the increase amount of the vehicle speed spd and the increase amount of the engine sound pressure is linear, that is, This indicates that the ratio between the increase amount of the vehicle speed spd and the increase amount of the engine sound pressure is constant. Even if the relationship between the increase amount of the vehicle speed spd and the increase amount of the engine sound pressure is not completely linear, the target engine rotation speed nintgt is corrected based on the sound pressure characteristics of the engine 1 to Compared with the case where the sound pressure characteristic of 1 is not taken into account, the relationship between the increase amount of the vehicle speed spd and the increase amount of the engine sound pressure is made more linear. It is included in making the amount of increase in sound pressure proportional. In other words, making the increase amount of the engine sound pressure proportional to the increase amount of the vehicle speed spd is based on the sound pressure characteristic of the engine 1 as compared with the case where the sound pressure characteristic of the engine 1 is not considered. In other words, the variation of the increase amount of the engine sound pressure with respect to the increase amount of the vehicle speed spd is suppressed, that is, the variation range of the ratio between the increase amount of the vehicle speed spd and the increase amount of the engine sound pressure is reduced.

  FIG. 5 is a diagram showing the relationship between the engine rotational speed NIN and the engine sound pressure in the engine 1. FIG. 6 shows a shift line when the engine rotational speed NIN is proportional to the vehicle speed spd (see reference numeral 202) and a shift line when the target engine rotational speed nintgt is corrected during acceleration by the control of this embodiment (reference numeral 203). FIG. FIG. 7 is a diagram for explaining the effect when the target engine speed nintgt is corrected during acceleration by the control of the present embodiment.

  In FIG. 5, reference numeral 201 indicates the sound pressure level in the passenger compartment with respect to the engine speed NIN. As described above, the engine sound pressure 201 includes the region R5 in which the increase in the engine sound pressure 201 stagnate with respect to the increase in the engine rotation speed NIN, and the engine sound pressure 201 significantly increases with respect to the increase in the engine rotation speed NIN. Region R6 to be present.

  As described above, although there is a variation in the increase amount of the engine sound pressure 201 with respect to the increase amount of the engine rotation speed NIN depending on the region of the engine rotation speed NIN, as shown by the reference numeral 202 in FIG. When the shift control is performed to make NIN proportional to the vehicle speed spd, as shown in FIG. 7, the increase in engine sound pressure is stagnant during acceleration, or the engine sound pressure is excessively increased.

  In FIG. 7, reference numeral 204 indicates a temporal transition of engine sound pressure when the engine speed NIN is proportional to the vehicle speed spd during acceleration (see reference numeral 206). Reference numeral 205 indicates the target engine speed in the present embodiment. The time transition of the engine sound pressure when the speed nintgt is corrected (see reference numeral 207) is shown. When the engine speed NIN is made proportional to the vehicle speed spd evenly during acceleration, corresponding to a region where the increase in the engine sound pressure is stagnant with respect to the increase in the engine speed NIN (see reference numeral R5 in FIG. 5), As indicated by reference numeral R7 in FIG. 7, a phenomenon occurs in which the engine sound pressure 204 does not increase even though the engine rotational speed 206 increases. Thus, when the engine sound pressure 204 does not increase so much, it is difficult for the driver to feel a sufficient acceleration feeling. For this reason, there is a problem that the region where the driver feels “feeling of stretching” is limited to a narrow region (acceleration condition) indicated by the arrow Y1.

  In contrast, in the present embodiment, the target engine rotational speed nintgt is corrected so that the increase amount of the engine sound pressure is proportional to the increase amount of the vehicle speed spd. That is, in the speed change line 203 (see FIG. 6) at the time of acceleration according to the present embodiment, the vehicle speed spd as indicated by reference numeral 210 in the region R5 where the increase in the engine sound pressure is stagnant with respect to the increase in the engine speed NIN. The engine speed NIN is greatly increased with respect to the increase amount. In this case, the engine speed NIN is increased by shifting the continuously variable transmission 2 to a lower gear ratio. Thereby, the fluctuation in the increase rate of the engine sound pressure 205 (see FIG. 7) is suppressed, and the time during which the increase in the engine sound pressure 205 stagnates is shortened, so that the feeling of stagnation is suppressed and the driver can accelerate. You can feel a sense of growth.

  On the other hand, in the region R6 in which the engine sound pressure greatly increases with respect to the increase in the engine rotational speed NIN in the speed change line 203 (see FIG. 6) during acceleration according to the present embodiment, the vehicle speed spd increases as indicated by reference numeral 211. In contrast, an increase in the engine speed NIN is suppressed. In this case, the increase in the engine rotational speed NIN is moderated by shifting the continuously variable transmission 2 to a higher gear ratio. Thereby, it can suppress that the engine sound pressure 205 (refer FIG. 7) rises too much, and can suppress that an engine sound is felt noisy.

  Thus, by correcting the target engine rotational speed nintgt so that the increase amount of the engine sound pressure is proportional to the increase amount of the vehicle speed spd during acceleration, an appropriate engine sound pressure 205 is obtained under a wide range of acceleration conditions. Can be secured. As a result, the linear feeling with respect to the engine sound is improved, and the acceleration feeling is improved under a wide range of acceleration conditions. As shown by an arrow Y2 in FIG. 7, the driver can feel an “elongation” in acceleration in a wide speed range during acceleration.

  FIG. 8 is a diagram showing target values of the engine rotational speed NIN and the output torque TE during acceleration according to the present embodiment. In FIG. 8, reference numeral 103 indicates an isosonic pressure line connecting a combination (operating point) of the engine rotational speed NIN and the output torque TE at which the engine sound pressure becomes equal. Reference numeral 104 denotes an engine that is determined based on the sound pressure characteristic of the engine 1 (distribution of the equal sound pressure line 103) so that the increase amount of the vehicle speed spd and the increase amount of the engine sound pressure are proportional during acceleration. The characteristic line which shows the target value of rotational speed NIN and output torque TE is shown.

  As will be described below with reference to FIG. 9, at the time of acceleration, the target engine speed nintgt is determined based on the characteristic line 104 by adding a correction amount to a basic value proportional to the vehicle speed spd. To a value (a value that makes the increase amount of the vehicle speed spd and the increase amount of the engine sound pressure proportional to each other).

  FIG. 9 is a diagram for explaining correction contents of the target engine speed nintgt and the target engine torque trqtgt during acceleration according to the present embodiment. Reference numerals P1, P2, and P3 indicate equal power lines at which the output (power) of the engine 1 becomes equal. When the operating point of the engine 1 (combination of the engine rotational speed NIN and the output torque TE) is on the same equal power line, the output (power) of the engine 1 becomes equal. The output of the engine 1 becomes a large value in the order of the equal power line indicated by reference sign P1 to the equal power line indicated by reference sign P3.

  A method for correcting the target engine speed nintgt will be described by taking as an example the case where the equal power line corresponding to the target power P calculated by the target output calculation unit 21 is the equal power line indicated by reference numeral P2. When the basic target engine speed nintgt calculated so that the engine speed NIN is proportional to the vehicle speed spd is a value indicated by the symbol NIN1, this corresponds to the intersection of the equal power line P2 and the characteristic line 104. The correction amount is added to the target engine speed nintgt so as to be the value NIN2. In other words, the target power P of the engine 1 is left as it is (on the same equal power line), and correction is performed to change the operating point of the engine 1 to a point on the characteristic line 104. In this case, the target engine torque trqtgt is changed from the value indicated by the symbol TE1 to the value indicated by the symbol TE2 in accordance with the correction of the target engine speed nintgt.

  Since the engine sound pressure varies depending not only on the engine rotational speed NIN but also on the output torque TE of the engine 1, in this embodiment, the correction amount of the target engine rotational speed nintgt is based on the engine rotational speed NIN and the output torque TE. Is set. A map that defines the correction amount of the target engine speed nintgt for each combination of the engine speed NIN and the output torque TE is stored in the target control amount calculation unit 22. The target control amount calculation unit 22 corrects the target engine speed nintgt with reference to the map during acceleration.

  Next, the operation of this embodiment will be described with reference to FIGS. 10 and 11. FIG. 10 is a flowchart showing the operation of this embodiment. FIG. 11 is a diagram illustrating the transition of the target value of the input rotation speed of the continuously variable transmission 2 when the control according to the present embodiment is performed.

  First, in step S10, the target driving force calculation unit 10 detects the vehicle speed spd. The target driving force calculation unit 10 detects the vehicle speed spd based on the detection result of the vehicle speed detection means 4.

  Next, in step S20, the target driving force calculation unit 10 detects the accelerator opening degree accp. The target driving force calculation unit 10 detects the accelerator opening degree accp based on the detection result of the accelerator opening degree detection means 3.

  Next, at step S30, the vehicle travel control apparatus 100 calculates a determination threshold value α based on the vehicle speed spd detected at step S10 and the accelerator opening degree accp detected at step S20. The determination threshold value α is a threshold value of the accelerator opening degree accp for determining whether or not the vehicle is in an acceleration state. In other words, it is determined whether or not the driver requests acceleration of the vehicle by the determination threshold value α. The determination threshold value α is calculated as, for example, a threshold value for determining whether or not the target driving force Ftgt calculated from the current vehicle speed spd and the accelerator opening degree accp is a value that increases the vehicle speed spd. When step S30 is executed, the process proceeds to step S40.

  In step S40, the vehicle travel control device 100 determines whether or not the accelerator opening degree accp detected in step S20 is larger than the determination threshold value α. As a result of the determination, if it is determined that the accelerator opening degree accp is larger than the determination threshold value α (step S40-Y), the process proceeds to step S50, and if not (step S40-N), this control is performed. The flow is terminated. If a negative determination is made in step S40, the target engine speed nintgt and the target engine torque trqtgt are set so that the engine speed NIN is proportional to the vehicle speed spd.

  In step S50, the vehicle traveling control device 100 sets an acceleration determination flag. The acceleration determination flag is set when the vehicle is in an acceleration state, that is, when the driver requests to accelerate the vehicle.

  Next, in step S60, the control unit 30 calculates a target input rotation speed that is a target value of the input rotation speed of the continuously variable transmission 2. The target input rotation speed corresponds to the target engine rotation speed nintgt. In the following description, it is assumed that the target input rotation speed of the continuously variable transmission 2 is set to a value equal to the target engine rotation speed nintgt.

  The target output calculation unit 21 calculates the target power P based on the target driving force Ftgt calculated by the target driving force calculation unit 10. The target control amount calculation unit 22 calculates a target engine rotation speed nintgt based on the target power P. The target engine speed nintgt calculated in step S60 is a basic value calculated as a value that makes the engine speed NIN proportional to the vehicle speed spd. The target input rotation speed is set to a value equal to the target engine rotation speed nintgt by the control unit 30. In FIG. 11, reference numeral 211 indicates the basic target input rotation speed calculated in step S60.

  Next, in step S70, the control unit 30 calculates a correction amount for the target input rotation speed. The correction amount of the target input rotation speed and the correction amount of the target engine rotation speed nintgt are calculated based on the input rotation speed (engine rotation speed NIN) and the accelerator opening degree accp (load state). In other words, the correction amount of the target input rotation speed is the same as the correction amount of the target engine rotation speed nintgt, while the target power P of the engine 1 remains unchanged, and the operating point of the engine 1 is on the characteristic line 104 (see FIG. 9). Calculated as a value to change to a point.

  The target control amount calculation unit 22 calculates a correction amount for the target engine speed nintgt with reference to a map stored in advance based on the engine speed NIN and the output torque TE. Similarly, the control unit 30 calculates a correction amount for the target input rotation speed with reference to a map stored in advance based on the input rotation speed and the output torque TE. In FIG. 11, reference numeral 213 indicates a correction amount of the target input rotation speed.

  Next, in step S80, the control unit 30 adds the correction amount 213 of the target input rotation speed calculated in step S70 to the target input rotation speed 211 calculated in step S60. In FIG. 11, reference numeral 212 indicates the target input rotation speed after the correction amount 213 of the target input rotation speed is added, that is, the final target input rotation speed. Further, the target control amount calculation unit 22 calculates the final target engine speed nintgt by adding the correction amount of the target engine speed nintgt calculated in step S70 to the target engine speed nintgt calculated in step S60. To do. When step S80 is executed, this control flow is returned.

  The control unit 30 performs shift control of the continuously variable transmission 2 based on the final target input rotation speed 212 calculated in step S80, and the final target engine rotation speed nintgt calculated in step S80. The operation of the engine 1 is controlled based on the target engine torque trqtgt set correspondingly.

  According to the present embodiment, at the time of acceleration, the target input rotation speed (target engine rotation speed nintgt) is set so that the increase amount of the engine sound pressure is proportional to the increase amount of the vehicle speed spd. As a result, it is possible to suppress an increase in engine sound pressure during acceleration or an excessive increase in engine sound pressure, and to ensure an appropriate increase in engine sound pressure. As a result, the linear feeling with respect to the engine sound is improved, and the acceleration feeling is improved under a wide range of acceleration conditions.

  Instead of correcting the target engine rotational speed nintgt and the target input rotational speed as in the present embodiment, for example, a device for adjusting the sound pressure may be provided in the exhaust passage or the like as means for adjusting the engine sound pressure. However, in this case, it is difficult to make the increase amount of the engine sound pressure proportional to the increase amount of the vehicle speed spd. This is because the change amount of the engine sound pressure with respect to the change amount of the engine rotation speed NIN varies depending on the region of the engine rotation speed NIN, the frequency component of the engine sound varies depending on the engine rotation speed NIN, and the like. On the other hand, in the present embodiment, the engine speed NIN is controlled according to the vehicle speed spd, based on a characteristic between the engine speed NIN and the engine sound pressure obtained in advance (engine sound pressure characteristic). . Thereby, it is possible to easily make the increase amount of the engine sound pressure proportional to the increase amount of the vehicle speed spd.

  In the present embodiment, since the engine rotational speed NIN and the engine sound pressure both increase as the vehicle speed spd increases during acceleration, it is possible to appropriately give the driver a feeling of acceleration according to the change in the vehicle speed. .

  In the present embodiment, the engine sound pressure that is proportionally increased with respect to the increase amount of the vehicle speed spd is the sound pressure of the engine sound detected in the vehicle interior. The sound pressure of the engine sound detected outside the room may be increased in proportion to the increase amount of the vehicle speed spd. Even in this case, it is possible to increase the engine sound pressure felt by the driver in accordance with the increase in the vehicle speed spd, and the effect of giving the driver a feeling of acceleration corresponding to the change in the vehicle speed spd is achieved. Can do.

  In the present embodiment, the correction amount of the target input rotation speed is calculated based on the input rotation speed and the accelerator opening degree accp. Instead, the correction amount of the target input rotation speed is calculated based only on the input rotation speed. May be.

  In the present embodiment, the description has been made on the assumption that the target engine speed nintgt before correction at the time of acceleration is set as a value proportional to the vehicle speed spd. Is not limited to this. Even if the target engine speed nintgt before the correction is not a value proportional to the vehicle speed spd, the increase in the engine sound pressure is increased with respect to the increase in the vehicle speed spd during the acceleration by the correction considering the engine sound pressure characteristics of the present embodiment. The target engine speed nintgt can be corrected so as to be proportional.

(Second Embodiment)
A second embodiment will be described with reference to FIGS. In the second embodiment, only differences from the first embodiment will be described.

  In the first embodiment (FIG. 10), the increase amount of the engine sound pressure is proportional to the increase amount of the vehicle speed spd during acceleration with respect to the basic target engine speed nintgt calculated so as to be proportional to the vehicle speed spd. The correction was made to make it correct. In the present embodiment, the target engine rotation speed nintgt is calculated by selectively referring to two shift lines, that is, a shift line when accelerating and a shift line when not accelerating. In the speed change line for acceleration, the target engine speed nintgt is set so that the increase amount of the engine sound pressure is proportional to the increase amount of the vehicle speed spd.

  FIG. 12 is a diagram showing a relationship between the vehicle speed spd determined based on the two shift lines referred to in the present embodiment and the target input rotation speed. Reference numeral 301 indicates the relationship between the vehicle speed spd determined based on the shift line when not accelerating and the target input rotation speed. When not accelerating, the target input rotation speed is set to a value proportional to the vehicle speed spd.

  Reference numeral 302 indicates the relationship between the vehicle speed spd determined based on the shift line during acceleration and the target input rotation speed. In a region where the increase in engine sound pressure stagnate with an increase in engine speed NIN, as indicated by reference numeral 310, the target input speed (target engine speed nintgt) is increased with respect to the increase in vehicle speed spd during acceleration. Raise. On the other hand, in a region where the engine sound pressure greatly increases with an increase in the engine rotational speed NIN, as indicated by reference numeral 311, the target input rotational speed (target engine rotational speed nintgt) is increased with respect to the increase amount of the vehicle speed spd during acceleration. Let the rise be small.

  The operation of this embodiment will be described with reference to FIGS. FIG. 13 is a flowchart showing the operation of this embodiment. FIG. 14 is a diagram illustrating a transition of the target input rotation speed when the control according to the present embodiment is performed.

  Steps S110 to S150 can be the same as steps S10 to S50 in the first embodiment (FIG. 10). That is, the vehicle speed spd is detected (step S110), the accelerator opening degree accp is detected (step S120), and the determination threshold value α is calculated based on the vehicle speed spd and the accelerator opening degree accp (step S130). Is greater than the determination threshold value α (step S140). If a positive determination is made as a result of the determination (step S140-Y), an acceleration determination flag is set in step S150.

  Next, in step S160, the target input rotation speed is calculated by the control unit 30. The control unit 30 calculates a target input rotation speed based on the target engine rotation speed nintgt calculated by the target control amount calculation unit 22. The target input rotational speed (target engine rotational speed) calculated in step S160 is the target input rotational speed (target engine rotational speed) nintgt2 during acceleration in consideration of the characteristics of the engine sound pressure. The target input rotational speed nintgt2 in consideration of the characteristics of the engine sound pressure is calculated based on the shift line at the time of acceleration, and is a value that makes the increase amount of the engine sound pressure proportional to the increase amount of the vehicle speed spd. It is. In FIG. 14, reference numeral 313 indicates a target input rotational speed (target engine rotational speed) nintgt2 at the time of acceleration in consideration of the characteristics of the engine sound pressure. When step S160 is executed, this control flow is returned.

  When a negative determination is made in step S140 and the process proceeds to step S170, the target input rotation speed is calculated in step S170. The target input rotation speed calculated in step S170 is the target engine rotation speed nintgt calculated as a value that makes the engine rotation speed NIN proportional to the vehicle speed spd. In FIG. 14, reference numeral 312 indicates the target input rotational speed (target engine rotational speed) nintgt calculated in step S170. When step S170 is executed, this control flow is returned.

1 is a block diagram according to a first embodiment of a vehicle travel control device of the present invention. FIG. It is a figure which shows the correspondence of the accelerator opening degree and vehicle speed, and target drive force in 1st Embodiment of the vehicle travel control apparatus of this invention. It is a figure which shows an example of the relationship between an engine speed and an engine sound pressure. It is a figure which shows an example of the time transition of the engine speed at the time of acceleration at the time of making an engine speed proportional to a vehicle speed, and an engine sound pressure. It is a figure which shows the relationship between the engine rotational speed and engine sound pressure of 1st Embodiment of the vehicle travel control apparatus of this invention. In the first embodiment of the vehicle travel control device of the present invention, it is a diagram showing a shift line when the engine rotation speed is proportional to the vehicle speed and a shift line when the target engine rotation speed is corrected during acceleration. It is a figure for demonstrating the effect when the target engine rotational speed is correct | amended at the time of acceleration in 1st Embodiment of the vehicle travel control apparatus of this invention. It is a diagram which shows the target value of the engine rotational speed and output torque at the time of acceleration of 1st Embodiment of the vehicle travel control apparatus of this invention. It is a figure for demonstrating the correction content of the target engine rotational speed and target engine torque at the time of the acceleration of 1st Embodiment of the vehicle travel control apparatus of this invention. It is a flowchart which shows operation | movement of 1st Embodiment of the vehicle travel control apparatus of this invention. It is a figure which shows transition of the target value of input rotational speed when control of 1st Embodiment of the vehicle travel control apparatus of this invention is performed. It is a figure which shows the relationship between the vehicle speed determined based on two shift lines and target input rotational speed in 2nd Embodiment of the vehicle travel control apparatus of this invention. It is a flowchart which shows operation | movement of 2nd Embodiment of the vehicle travel control apparatus of this invention. It is a figure which shows transition of the target input rotational speed when control of 2nd Embodiment of the vehicle travel control apparatus of this invention is performed.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Engine 2 Continuously variable transmission 3 Accelerator opening degree detection means 4 Vehicle speed detection means 10 Target driving force calculation part 20 Control amount calculation part 21 Target output calculation part 22 Target control amount calculation part 30 Control part 100 Vehicle travel control apparatus 103 Isotone Pressure line 104 Characteristic line accp Accelerator opening Ftgt Target driving force NIN Engine speed nintgt Target engine speed nintgt2 Target input speed considering engine sound pressure characteristics P1, P2, P3 Constant power line P Target power spd Vehicle speed TE output Torque trqtgt Target engine torque

Claims (3)

The internal combustion engine and a continuously variable transmission that transmits the output of the internal combustion engine to a drive shaft are provided in a vehicle, and the internal combustion engine is configured to achieve a target rotational speed that is a target value of the rotational speed of the internal combustion engine. A vehicle travel control device for controlling an engine and the continuously variable transmission,
Setting means for setting the target rotational speed based on the vehicle speed;
Determination means for determining whether or not the vehicle is in an acceleration state,
The setting means, when the determination means determines that the vehicle is in an acceleration state, the increase amount of the sound pressure of the internal combustion engine is proportional to the increase amount of the vehicle speed. A vehicle travel control device characterized in that a target rotational speed is set. In the vehicle travel control device according to claim 1,
The setting means increases the target rotational speed as the vehicle speed increases, and in a region of the rotational speed where the increase amount of the sound pressure is small relative to the rotational speed increase amount, The vehicle travel control device, wherein the increase amount of the target rotation speed with respect to the increase amount of the vehicle speed is made larger than that of the rotation speed region where the increase amount of the sound pressure with respect to the increase amount is large. In the vehicle travel control device according to claim 1 or 2,
The vehicle travel control apparatus characterized in that the target rotational speed is realized by changing the rotational speed by shift control of the continuously variable transmission.

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