JP2019217994A - Vehicle control system and manufacturing method of the same - Google Patents

Abstract

To provide a vehicle control system which can improve responsiveness of the vehicle corresponding to steering operation even in a case of a rear wheel drive vehicle.SOLUTION: A vehicle control system of controlling a vehicle rear wheels of which are driven comprises: a driving state sensor detecting a driving state of the vehicle; a steering angle sensor detecting a steering angle; and a controller controlling a motor on the basis of the detection signal of the driving state sensor and the detection signal of the steering angle sensor. The controller sets a basic torque on the basis of the detection signal of the driving state sensor, and sets, when detecting increase of the steering angle (S21 YES), increase torque to increase the basic torque (S25), and to control a motor to generate torque in which increase torque is added to the basic torque. The controller is constituted capable of varying the increase torque (S26), in a case that a longitudinal spring constant is small, to largely increase the basic torque in comparison with a case that it is large.SELECTED DRAWING: Figure 4

Description

  The present invention relates to a vehicle control system, and more particularly, to a vehicle control system and method for controlling a vehicle whose rear wheels are driven by a prime mover.

  Japanese Patent No. 5143103 (Patent Document 1) discloses a vehicle motion control device. In the vehicle motion control device described in Patent Document 1, by automatically giving a deceleration to the vehicle in accordance with the steering of the vehicle, the vehicle is prevented from skidding in a limit driving region, and the steering stability of the vehicle is improved. Have improved.

  Further, Japanese Patent No. 62202478 (Patent Document 2) describes a behavior control device for a vehicle. In the vehicle behavior control device described in Patent Document 2, the driving force of the vehicle is reduced based on the steering speed of the vehicle so as to add the target additional deceleration to the vehicle. As described above, in the vehicle behavior control device described in Patent Document 2, the vertical load on the front wheels of the vehicle is increased by reducing the driving force of the vehicle in accordance with the steering speed. As a result, the vehicle behavior in response to the driver's steering operation is reduced. It has succeeded in improving responsiveness and linear feeling.

Japanese Patent No. 5143103 Japanese Patent No. 6202478

  However, when the present inventor tried to apply the control for decelerating the vehicle in accordance with the steering of the vehicle as described in Patent Literature 1 and Patent Literature 2 to a rear wheel drive vehicle, It was not possible to obtain the effects of improving the steering stability, the response of the vehicle behavior, and the linear feeling obtained in the inventions described in Documents 1 and 2.

  That is, as the vehicle attitude control, as described in Patent Literatures 1 and 2, etc., control for applying a deceleration to the vehicle in accordance with the steering operation of the vehicle is applied. However, when such conventionally known vehicle attitude control is applied to a rear-wheel drive vehicle, it is possible to obtain an effect such as improvement in vehicle responsiveness and linear feeling as obtained in a front-wheel drive vehicle. Could not. As a result of intensive research conducted by the present inventors to solve this newly discovered problem, in a rear-wheel drive vehicle, surprisingly, the drive torque of the vehicle is increased according to the steering by the driver. It was clarified that the vehicle responsiveness and the linear feeling improved.

  In general, when deceleration is applied to a vehicle, the inertia force acting on the center of gravity of the vehicle causes a pitching motion in which the front side sinks in the vehicle. It was thought to improve. However, in a rear-wheel drive vehicle, when deceleration is given to the vehicle by reducing the drive torque of the rear wheels, in addition to the inertia force described above, the vehicle body is tilted rearward from the rear wheels via the suspension (the rear side is (Sinking) force is instantaneously generated. Since this instantaneous force acts to reduce the load on the front wheels, in a rear-wheel drive vehicle, even if deceleration is applied to the vehicle in accordance with the steering by the driver, the vehicle responsiveness and linear feeling are expected as expected. It is probable that it could not be improved.

  Conversely, in a rear-wheel drive vehicle, by increasing the drive torque of the rear wheels, a force that causes the body to lean forward (sink the front side) from the rear wheels via the suspension acts instantaneously. Therefore, it is considered that the responsiveness and linear feeling of the vehicle are improved because the front wheel load increases. That is, in a rear-wheel drive vehicle, when acceleration is given by increasing the drive torque of the rear wheels, an inertial force for leaning the vehicle body and an instantaneous force for leaning the vehicle body are generated. It is considered that the momentary forward leaning force predominantly contributes to gender and linearity.

The present inventor sets the increased torque so as to increase the basic torque based on the increase in the steering angle of the steering device mounted on the vehicle. It has been found that the vehicle responsiveness and linear feeling to steering operation can be improved. However, the effect of increasing the torque varies depending on the longitudinal spring constant of the tire of the front wheel, which is the steered wheel, and a new technical problem that a sufficient effect may not be obtained even when the same increased torque is applied may occur. Found by others. That is, when the vertical spring constant of the tire is small, even if the load on the steered wheels is increased by setting the increased torque, the increase in the load is insufficient, and the responsiveness of the vehicle cannot be sufficiently improved. The present invention has been made to solve this new technical problem.
Therefore, the present invention provides a vehicle control system capable of improving the responsiveness or linear feeling of a vehicle to a steering operation even when controlling a vehicle whose rear wheels are driven by a prime mover, and a method of manufacturing the same. It is aimed at.

In order to solve the above-described problem, the present invention is a vehicle control system for controlling a vehicle in which a rear wheel is driven by a prime mover, comprising: a driving state sensor for detecting a driving state of the vehicle; A steering angle sensor that detects a steering angle of the device; and a controller that controls the prime mover based on a detection signal of the driving state sensor and a detection signal of the steering angle sensor. Based on the basic torque, the basic torque to be generated by the prime mover is set, and when the increase in the steering angle is detected by the steering angle sensor, the increase torque is set so as to increase the basic torque, and the increase torque is added to the basic torque. The controller is configured to control the prime mover so that the generated torque is generated, and the controller controls the basic torque when the longitudinal spring constant of the tire mounted on the vehicle is smaller than when the longitudinal spring constant is large. As is greatly increased, it is characterized in that it is capable of changing the torque increase.
According to the present invention thus configured, the increased torque can be changed so that when the longitudinal spring constant of the tire mounted on the vehicle is small, the basic torque is increased more than when the longitudinal spring constant is large. Configured. Thereby, even when the longitudinal spring constant of the tire of the vehicle is small, the vehicle responsiveness and the linear feeling can be sufficiently improved.

  In the present invention, preferably, the controller increases the rate of increase of the increased torque per unit time when the longitudinal spring constant of the tire mounted on the vehicle is smaller than when the longitudinal spring constant is large, Increase the basic torque.

  According to the present invention configured as described above, when the longitudinal spring constant of the tire is small, the basic torque is increased by increasing the increase rate of the increased torque per unit time, so that the load on the steered wheels is reduced. The vehicle response and the linear feeling can be sufficiently improved even when the longitudinal spring constant is small.

  In the present invention, preferably, the controller increases the basic torque by setting the value of the increased torque to be larger when the longitudinal spring constant of the tire mounted on the vehicle is small than when the longitudinal spring constant is large. Let it.

  According to the present invention thus configured, when the longitudinal spring constant of the tire is small, the basic torque is increased by increasing the value of the increased torque, so that the load on the steered wheels can be increased. Even when the vertical spring constant is small, the vehicle responsiveness and the linear feeling can be sufficiently improved.

  In the present invention, preferably, the controller sets the reduced torque such that the basic torque is reduced based on a decrease in the steering angle of the steering device mounted on the vehicle, and subtracts the reduced torque from the basic torque. The controller is configured to control the prime mover so that torque is generated, and the controller reduces the basic torque more strongly when the longitudinal spring constant of the tire mounted on the vehicle is smaller than when the longitudinal spring constant is larger. Thus, the reduction torque can be changed.

  In the present invention thus configured, the reduced torque is set based on the decrease in the steering angle of the steering device mounted on the vehicle so that the basic torque is reduced. In a rear-wheel drive vehicle, by reducing the drive torque of the rear wheels, a force that causes the vehicle body to lean backward (submerge the rear side) from the rear wheels via the suspension acts instantaneously and the load on the front wheels decreases. . As described above, when the load on the steered wheels is reduced at the time of turning back the steering wheel (when the steering angle is reduced), the vehicle can smoothly transition from the turning state to the straight traveling state, and the vehicle response to the turning back of the steering wheel can be achieved. Performance can be improved.

  However, when the longitudinal spring constant of the tire mounted on the vehicle is small, a new problem arises in that the load on the steered wheels is not sufficiently reduced even if the vehicle body is tilted backward by reducing the driving torque. According to the present invention configured as described above, when the longitudinal spring constant of the tire is small, the basic torque is reduced more strongly than when the longitudinal spring constant is large. As a result, the load on the steered wheels can be sufficiently reduced, and the responsiveness of the vehicle to turning back of the steering wheel can be improved.

  Further, the present invention is a method for manufacturing a vehicle control system for controlling a vehicle in which rear wheels are driven by a prime mover, wherein the driving state sensor detects a driving state of the vehicle, and a steering angle of a steering device mounted on the vehicle. A step of preparing a controller that controls the prime mover based on a steering angle sensor to detect, and a detection signal of the driving state sensor and a detection signal of the steering angle sensor; anda step of preparing a tire to be mounted as a steered wheel of the vehicle. The controller sets a basic torque to be generated by the prime mover based on a detection signal of the driving state sensor, and increases the basic torque when an increase in the steering angle is detected by the steering angle sensor. It is configured to set the increased torque and to control the prime mover so that a torque obtained by adding the increased torque to the basic torque is generated, and further, a tire having a small vertical spring constant is mounted on the vehicle. That case, the vertical spring constant than when mounting the large tires, so as to increase the basic torque increase is characterized by having a parameter setting step of setting a control parameter of the controller, a.

  According to the vehicle control system and the method of manufacturing the same of the present invention, the responsiveness or linear feeling of the vehicle to the steering operation can be improved even when controlling the vehicle in which the rear wheels are driven by the prime mover.

It is a block diagram showing the whole composition of vehicles carrying a vehicle control system by an embodiment of the present invention. FIG. 1 is a block diagram illustrating an electrical configuration of a vehicle control system according to an embodiment of the present invention. 4 is a flowchart of an engine control process in which a PCM included in a vehicle control system according to an embodiment of the present invention controls an engine. 9 is a flowchart of a torque addition amount setting process in which the PCM determines an increased torque in the embodiment of the present invention. 4 is a map showing a relationship between a target additional acceleration determined by PCM and a steering speed in the embodiment of the present invention. 3 is a map showing an example of a relationship between a vertical spring constant of a tire and a tire vertical spring correction coefficient in the embodiment of the present invention. 4 is a map showing a relationship between a target additional deceleration determined by PCM and a steering speed in the embodiment of the present invention. 5 is a time chart illustrating an example of an operation of the vehicle control system according to the embodiment of the present invention. It is a flowchart of the manufacturing procedure in the manufacturing method of the vehicle control system according to the embodiment of the present invention.

Next, a preferred embodiment of the present invention will be described with reference to the accompanying drawings.
First, a vehicle equipped with a vehicle control system according to an embodiment of the present invention will be described with reference to FIG. FIG. 1 is a block diagram showing an overall configuration of a vehicle equipped with a vehicle control system according to an embodiment of the present invention.

In FIG. 1, reference numeral 1 denotes a vehicle equipped with the vehicle control system according to the present embodiment.
Left and right front wheels 2a, which are steering wheels, are provided at the front of the vehicle body of the vehicle 1, and left and right rear wheels 2b, which are driving wheels, are provided at the rear of the vehicle body. The front wheel 2a and the rear wheel 2b of the vehicle 1 are supported by a suspension 3 with respect to the vehicle body. In addition, an engine 4 which is a prime mover for driving the rear wheel 2b is mounted at a front portion of the vehicle body of the vehicle 1. In the present embodiment, the engine 4 is a gasoline engine. However, an internal combustion engine such as a diesel engine or a motor driven by electric power can be used as a prime mover. In the present embodiment, the vehicle 1 is a so-called FR vehicle in which a rear wheel 2b is driven by an engine 4 mounted on a front portion of the vehicle body via a transmission 4a, a propeller shaft 4b, and a differential gear 4c. The present invention can be applied to any vehicle in which the rear wheels are driven by the prime mover, such as a so-called RR vehicle in which the rear wheels 2b are driven by the engine 4 mounted on the rear.

  The vehicle 1 is equipped with a steering device 7 that steers the front wheels 2a based on a rotation operation of the steering wheel 6. Further, the vehicle 1 detects a steering angle sensor 8 that detects a rotation angle of the steering wheel 6, an accelerator opening sensor 10 that is a driving state sensor that detects an amount of depression of an accelerator pedal (accelerator opening), and a vehicle speed. It has a vehicle speed sensor 12. Each of these sensors outputs a detected value to a PCM (Power-train Control Module) 14 which is a controller. The vehicle control system according to the embodiment of the present invention includes the steering angle sensor 8, the accelerator opening sensor 10, the vehicle speed sensor 12, and the PCM 14.

  Next, an electric configuration of the vehicle control system according to the embodiment of the present invention will be described with reference to FIG. FIG. 2 is a block diagram showing an electric configuration of the vehicle control system according to the embodiment of the present invention.

  The PCM 14 detects various parts of the engine 4 (for example, the throttle valve 5a, the injector 5b, and the ignition plug) based on the detection signals of the sensors 8 to 12 and the detection signals output by various sensors for detecting the operating state of the engine 4. 5c, the variable valve mechanism 5d, etc.).

  The PCM 14 includes a basic torque setting unit 16, an increasing torque setting unit 18, a decreasing torque setting unit 20, an engine control unit 22, and a parameter storage unit 23. The basic torque setting unit 16 is configured to set a basic torque to be generated by the engine 4 based on a detection signal from the accelerator opening sensor 10 or the like, which is an operation state sensor. The increased torque setting unit 18 is configured to set the increased torque so as to increase the basic torque when the increase in the steering angle is detected by the steering angle sensor 8. The reduced torque setting unit 20 is configured to set the reduced torque so that when the steering angle sensor 8 detects a decrease in the steering angle, the basic torque is reduced. The engine control unit 22 is configured to control the engine 4 so as to generate a torque obtained by adding the increased torque to the basic torque or a torque obtained by subtracting the reduced torque. The parameter storage unit 23 is configured to store various calculation parameters used when calculating the increase torque and the decrease torque.

  The components of the PCM 14 include a CPU, various programs interpreted and executed on the CPU (including a basic control program such as an OS, and an application program activated on the OS and implementing a specific function), and programs and the like. It is constituted by a computer having an internal memory such as a ROM or a RAM for storing various data.

  Although not shown in FIG. 2, a brake sensor, an engine speed sensor, or the like may be provided as a driving state sensor in addition to the accelerator opening sensor 10 and the vehicle speed sensor 12. The engine control unit 22 controls a torque generated by the engine 4 by controlling a fuel injection valve, a spark plug, an intake throttle valve, an intake variable valve mechanism (not shown), and the like provided in the engine 4. It is configured to

Next, a vehicle control method executed by the vehicle control system according to the embodiment of the present invention will be described with reference to FIGS.
FIG. 3 is a flowchart of an engine control process in which the PCM 14 provided in the vehicle control system according to the embodiment of the present invention controls the engine 4.

The engine control process of FIG. 3 is started when the ignition of the vehicle 1 is turned on and the power is turned on to the vehicle control system, and is repeatedly executed.
When the engine control process is started, as shown in FIG. 3, in step S1, the PCM 14 reads and acquires various sensor signals relating to the driving state of the vehicle 1. Specifically, the PCM 14 includes a steering angle detected by the steering angle sensor 8, an accelerator opening detected by the accelerator opening sensor 10, a vehicle speed detected by the vehicle speed sensor 12, and a gear currently set for the transmission of the vehicle 1. The detection signals output from the various sensors described above, including the steps, are acquired as information relating to the operating state.

  Next, in step S2, the basic torque setting unit 16 of the PCM 14 sets a target acceleration based on the operation state of the vehicle 1 including the operation of the accelerator pedal and the vehicle speed acquired in step S1. Specifically, the basic torque setting unit 16 determines the current vehicle speed and gear position from an acceleration characteristic map (prepared and stored in a memory or the like) defined for various vehicle speeds and various gear positions. Is selected, and the target acceleration corresponding to the current accelerator opening is determined with reference to the selected acceleration characteristic map.

  Next, in step S3, the basic torque setting unit 16 determines a basic torque of the engine 4 for realizing the target acceleration determined in step S2. That is, the basic torque setting unit 16 sets the basic torque to be generated by the engine 4 as the prime mover based on the operating state of the vehicle 1 as a basic torque setting step. In this case, the basic torque setting unit 16 determines the basic torque within the range of the torque that can be output by the engine 4 based on the current vehicle speed, gear position, road surface gradient, road surface μ, and the like.

  On the other hand, in parallel with the processing in steps S2 and S3, in step S4, the increasing torque setting unit 18 and the decreasing torque setting unit 20 determine a torque for adding acceleration or deceleration to the vehicle 1 based on the steering operation. Execute the torque addition amount setting process. That is, in step S4, based on an increase in the steering angle of the steering device 7, an increase torque setting step of setting the increase torque so as to increase the basic torque, or on the basis of a decrease in the steering angle of the steering device, A reduced torque setting step of setting a reduced torque is performed so that the torque is reduced. This torque addition amount setting processing will be described later with reference to FIG.

  After performing the processing of steps S2 and S3 and the torque addition amount setting processing of step S4, in step S5, the increased torque or the reduced torque determined in the torque addition amount setting processing of step S4 is added to the basic torque determined in step S3. By adding or subtracting, the final target torque is determined. Here, while the basic torque is a torque set according to the driver's driving operation such as operation of the accelerator pedal, the increasing torque and the decreasing torque are set so that the vehicle 1 shows a behavior closer to the driver's intention. This torque is automatically added or reduced by the PCM 14.

  Next, in step S6, the PCM 14 sets an actuator control amount for realizing the final target torque set in step S5. Specifically, the PCM 14 determines various state quantities necessary for realizing the final target torque based on the final target torque set in step S5, and based on those state quantities, determines each component of the engine 4. Set the control amount of each actuator that drives. In this case, the PCM 14 sets a limit value or a limit range according to the state amount, and sets a control amount of each actuator such that the state value complies with the limit by the limit value or the limit range.

Subsequently, in step S7, the PCM 14 outputs a control command to each actuator based on the control amount set in step S6.
For example, when the engine 4 is a gasoline engine, the PCM 14 determines the ignition timing of the ignition plug 5c to generate the basic torque when the final target torque is set by adding the increased torque to the basic torque in step S5. Is advanced more than the ignition timing of. Instead of or in conjunction with the advance of the ignition timing, the PCM 14 increases the throttle opening or advances the closing timing of the intake valve set after the bottom dead center, thereby increasing the intake air. Increase the amount. In this case, the PCM 14 increases the fuel injection amount by the injector 5b in response to the increase in the intake air amount so that the predetermined air-fuel ratio is maintained.

  On the other hand, when the final target torque is set by subtracting the reduced torque from the basic torque in step S5, the PCM 14 delays the ignition timing of the ignition plug 5c from the ignition timing for generating the basic torque. (Retard). Further, instead of or in addition to the retardation of the ignition timing, the PCM 14 reduces the throttle opening degree or retards the closing timing of the intake valve set after the bottom dead center to thereby reduce the intake air. Decrease the amount. In this case, the PCM 14 reduces the fuel injection amount by the injector 5b in response to the increase in the intake air amount so that the predetermined air-fuel ratio is maintained.

  When the engine 4 is a diesel engine, the PCM 14 determines the amount of fuel injection by the injector 5b to generate the basic torque when the final target torque is set by adding the increased torque to the basic torque in step S5. The fuel injection amount is increased. On the other hand, when the final target torque is set by subtracting the reduced torque from the basic torque in step S5, the PCM 14 reduces the fuel injection amount by the injector 5b to less than the fuel injection amount for generating the basic torque. .

  After step S7, the PCM 14 ends one engine control process according to the flowchart shown in FIG.

Next, with reference to FIGS. 4 to 7, the torque addition amount setting processing executed in step S4 of FIG. 3 will be described.
FIG. 4 is a flowchart of a torque addition amount setting process in which the PCM 14 determines the increased torque in the embodiment of the present invention. FIG. FIG. FIG. 6 is a map showing an example of the relationship between the tire vertical spring constant and the tire vertical spring correction coefficient K1. FIG. 7 is a map showing the relationship between the target additional deceleration and the steering speed stored in the parameter storage unit 23 of the PCM 14.

  When the torque addition amount setting process shown in FIG. 4 is started, in step S21, the PCM 14 determines whether or not the steering angle of the steering device 7 obtained in step S1 of the flowchart shown in FIG. That is, the steering angle (absolute value) is set to zero when the vehicle 1 goes straight, and increases when the steering wheel 6 is rotated clockwise or counterclockwise. In the present embodiment, the steering angle is detected by the steering angle sensor 8 provided on the steering shaft that constitutes the steering device 7. However, an arbitrary sensor such as a sensor that detects the angle of the front wheels 2a (steered wheels) is used. The steering angle can be detected by the sensor.

  If it is determined in step S21 that the steering angle (absolute value) has not increased, the process proceeds to step S22, where it is determined whether the steering angle (absolute value) has decreased. That is, in step S22, it is determined whether or not the rotation angle of the steering wheel 6 is approaching the state of the steering angle = 0. If it is determined in step S22 that the steering angle has not decreased, one process of the flowchart illustrated in FIG. 4 ends, and the process returns to the main routine illustrated in FIG. That is, when the driver does not perform the steering operation (steering speed = 0), the increasing torque or the decreasing torque is not set, and the basic torque set in step S3 of FIG. 3 becomes the final target torque. It is determined.

On the other hand, when it is determined in step S21 that the steering angle has increased, the process proceeds to step S23, and in step S23, it is determined whether the steering speed is equal to or higher than a predetermined value. That is, the PCM 14 calculates a steering speed based on the steering angle acquired in step S1 of FIG. 3, and determines whether or not the value is equal to or greater than a predetermined threshold T _S1 . If the steering speed is not equal to or greater than the predetermined threshold value T _S1 , one process of the flowchart shown in FIG. 4 ends, and the process returns to the main routine shown in FIG. That is, when the steering speed is extremely low, it is considered that the driver does not intend to perform the steering, and the setting of the increased torque by the increased torque setting unit 18 is not executed. Thus, it is possible to prevent an unnecessary torque addition amount setting process from intervening in a state where the driver does not intend to perform steering.

  If it is determined in step S23 that the steering speed is equal to or higher than the predetermined value, the process proceeds to step S24. That is, when the driver turns the steering wheel 6 (Turn-in), the processes in and after step S24 are executed. In the processing of step S24 and subsequent steps, the increasing torque setting unit 18 sets an increasing amount (increase torque) of the output torque of the engine 4 necessary for adding acceleration to the vehicle 1 as an increasing torque setting step.

  First, in step S24, the increased torque setting unit 18 acquires a target additional acceleration based on the steering speed. The target additional acceleration is an acceleration to be applied to the vehicle 1 in accordance with a steering operation in order to accurately realize the vehicle behavior intended by the driver.

Specifically, the increase torque setting unit 18 acquires the target additional acceleration corresponding to the steering speed calculated in step S23 based on the relationship between the target additional acceleration and the steering speed shown in the map of FIG.
The horizontal axis in FIG. 5 indicates the steering speed, and the vertical axis indicates the target additional acceleration. As shown in FIG. 5, when the steering speed is equal to or less than the threshold value T _S1 , the corresponding target additional acceleration is zero. That is, when the steering speed is equal to or lower than the threshold value T _S1 , the PCM 14 does not execute the control for adding acceleration to the vehicle 1 based on the steering operation (returns to the main routine without setting the increased torque).

On the other hand, when the steering speed exceeds the threshold value T _S1 , as the steering speed increases, the target additional acceleration corresponding to the steering speed gradually _{approaches the} predetermined upper limit _Dmax . That is, as the steering speed increases, the target additional acceleration increases, and the increasing rate of the increase decreases. The upper limit value _Dmax is set to an acceleration that the driver does not feel that control intervention has occurred even if acceleration is added to the vehicle 1 in accordance with the steering operation (for example, 0.5 m / s ² ≒ 0.05 G). ). Further, when the steering speed is equal to or greater than a threshold value T _S2 greater than the threshold value T _S1 , the target additional deceleration is maintained at the upper limit value D _max .

In the present embodiment, the threshold value T _{S1 of the} steering speed is set to a constant value. However, as a modified example, the threshold value T _S1 is changed according to the basic torque set in step S3 of FIG. Can also be configured. In this case, when the basic torque is low, it is better to set the threshold value T _S1 higher than when the basic torque is high. As another modified example, the setting of the increased torque (target additional acceleration) is executed when the steering angle of the steering device 7 is equal to or larger than a predetermined steering angle threshold, and when the basic torque is low, the basic torque is set. The present invention can also be configured such that the steering angle threshold is set higher than when the steering angle is high.

  Next, in step S25, the increased torque, which is the amount of increase in torque required to realize the target additional acceleration acquired in step S24, is set by the increased torque setting unit 18.

  Further, in step S26, the increased torque set in step S25 is corrected based on various correction parameters stored in parameter storage unit 23 of PCM 14. As one of the stored correction parameters, there is a tire vertical spring correction coefficient K1 for the steered wheels. That is, the vehicle control system according to the embodiment of the present invention is configured to be mountable on various types of vehicles, but a standard specification tire to be mounted as a steering wheel is determined for each type of vehicle. For example, a tire having a smaller rim diameter than the tire outer diameter has a smaller vertical spring constant and a larger vertical deformation amount of the tire for the same vertical load. A tire having a high aspect ratio ([cross-section height of tire / cross-section width of tire] × 100%) has a smaller vertical spring constant than a tire having a lower aspect ratio and has the same vertical load. The amount of vertical deformation of the tire increases.

  Here, when the vertical spring constant of the tire is small, since the grip performance of the tire is lower than when the vertical spring constant of the tire is large, even if the vertical load of the steered wheels is increased by setting the increased torque, The responsiveness of the vehicle and the effect of improving the linear feeling are reduced. For this reason, in a vehicle control system mounted on a vehicle having a tire having a small vertical spring constant as a standard specification, it is necessary to correct the value of the increased torque to a larger value. Then, it is not necessary to set the value of the increase torque too large. In the vehicle control system of the present embodiment, the tire vertical spring correction coefficient K1 corresponding to the magnitude of the vertical spring constant of the tire, which is a standard specification for the type of vehicle to be mounted, is stored in the parameter storage unit 23 as described above.

  FIG. 6 is a map showing an example of the relationship between the tire vertical spring constant and the tire vertical spring correction coefficient K1. In the present embodiment, when the vehicle 1 or the PCM 14 is shipped from the factory, the vehicle 1 on which the vehicle control system is mounted (or should be mounted) has the tire according to the vertical spring constant of the standard tire as shown in FIG. The value of the vertical spring correction coefficient K1 is stored in the nonvolatile memory of the parameter storage unit 23. However, as a modified example, the present invention can also be configured so that the user or the maintenance company of the vehicle 1 can change / set the value of the tire vertical spring correction coefficient K1 according to the vertical spring constant of the mounted tire. Accordingly, even when a tire having a vertical spring constant other than the standard specification (a tire having a rim diameter or an oblateness different from that of the standard specification) is mounted, it is possible to set an appropriate increased torque.

  The increase torque setting unit 18 of the PCM 14 multiplies the tire longitudinal spring correction coefficient K1 stored in the parameter storage unit 23 by the increase torque set in step S25, and corrects the value of the increase torque, as shown in FIG. One process of the flowchart ends. After the end of the flowchart of FIG. 4, the process returns to step S5 of the flowchart shown in FIG. 3, which is the main routine. In step S5 of FIG. 3, as described above, the increased torque determined in the torque addition amount setting process (FIG. 4) is added to the basic torque, the final target torque is determined, and the engine is controlled so that this torque is generated. It is controlled (steps S6 and S7).

On the other hand, if it is determined in step S22 of FIG. 4 that the steering angle has decreased, the process proceeds to step S27, and in step S27, it is determined whether the steering speed is equal to or higher than a predetermined value. That is, the PCM 14 determines whether or not the steering speed is equal to or higher than the predetermined threshold T _S1 . If the steering speed is not equal to or greater than the predetermined threshold value T _S1 , one process of the flowchart shown in FIG. 4 ends, and the process returns to the main routine shown in FIG.

  If it is determined in step S27 that the steering speed is equal to or higher than the predetermined value, the process proceeds to step S28. That is, when the driver turns the steering wheel 6 back (Turn-out), the processes in and after step S28 are executed. In the processing after step S28, the amount of reduction (reduction torque) of the output torque of the engine 4 required to add deceleration to the vehicle 1 is set by the reduction torque setting unit 20 as a reduction torque setting step.

  First, in step S28, the reduced torque setting unit 20 acquires a target additional deceleration based on the steering speed. The target additional deceleration is a deceleration to be added to the vehicle 1 in accordance with the steering operation in order to accurately realize the vehicle behavior intended by the driver when the steering wheel 6 is turned back.

Specifically, the reduced torque setting unit 20 acquires the target additional deceleration corresponding to the steering speed calculated in step S27, using the additional deceleration map shown in FIG.
The horizontal axis in FIG. 7 indicates the steering speed, and the vertical axis indicates the target additional deceleration. As shown in FIG. 7, when the steering speed is equal to or less than the threshold value T _S1 , the corresponding target additional deceleration is zero. That is, when the steering speed is equal to or lower than the threshold value T _S1 , the PCM 14 does not execute the control for adding the deceleration to the vehicle 1 based on the steering operation (returns to the main routine without setting the reduction torque).

On the other hand, when the steering speed exceeds the threshold value T _S1 , as the steering speed increases, the target additional deceleration corresponding to the steering speed gradually _{approaches the} predetermined upper limit _Dmax . That is, as the steering speed increases, the target additional deceleration increases, and the increasing rate of the increase decreases. This upper limit value _Dmax is set to a deceleration that does not cause the driver to feel that control intervention has been performed even if deceleration is added to the vehicle 1 in accordance with the steering operation (for example, 0.5 m / s ² ≒ 0). .05G). Further, when the steering speed is equal to or greater than a threshold value T _S2 greater than the threshold value T _S1 , the target additional deceleration is maintained at the upper limit value D _max .

  Next, in step S29, the reduced torque setting unit 20 sets the reduced torque, which is the amount of reduction of the torque necessary to realize the target additional deceleration acquired in step S28.

  Next, in step S30, the reduced torque set in step S29 is corrected by multiplying by the tire vertical spring correction coefficient K1. Since the tire longitudinal spring correction coefficient K1 is set to a larger value as the longitudinal spring constant of the tire is smaller (FIG. 6), when the longitudinal spring constant is smaller, the value of the reduction torque is set larger, and the basic torque is stronger. Reduced. The tire vertical spring correction coefficient K1 used in step S30 may be different from the tire vertical spring correction coefficient K1 used in step S26 described above.

  The reduced torque setting unit 20 of the PCM 14 multiplies the set tire vertical spring correction coefficient K1 by the reduced torque set in step S29 to correct the value of the reduced torque, and performs one cycle of the flowchart shown in FIG. The process ends. After the end of the flowchart of FIG. 4, the process returns to step S5 of the flowchart shown in FIG. 3, which is the main routine. In step S5 of FIG. 3, the reduced torque determined in the torque addition amount setting process (FIG. 4) is subtracted from the basic torque, the final target torque is determined, and the engine 4 is controlled to generate this torque ( Steps S6 and S7). The step of controlling the engine 4 so as to generate a torque obtained by subtracting the reduced torque from the basic torque acts as a second torque generating step.

Next, the operation of the vehicle control system according to the embodiment of the present invention will be described with reference to FIG.
FIG. 8 is a time chart showing an example of the operation of the vehicle control system according to the present embodiment. In order from the top, the steering angle [deg], the steering speed [deg / sec], and the basic torque [N · m] of the steering device are shown. , Additional acceleration / deceleration [m / sec ² ], increase / decrease torque [N · m], and ignition timing.

At time t ₀ ~t ₁ in FIG. 8, the vehicle 1 the driver is not performing a steering, the steering angle 0 [deg] (neutral position), the steering speed becomes 0 [deg / sec] I have. Further, at time t ₀ ~t _1, the state of driving the vehicle 1 (e.g., the accelerator depression amount of the pedal) for also constant is, and the basic torque [N · m] is also a constant value. In this state, in the flowchart shown in FIG. 4, since the processing of steps S21 → S22 → return is repeated, the setting of the additional acceleration, the increasing torque, and the decreasing torque is not performed (the additional acceleration = 0, the additional torque = 0). , Reduced torque = 0). Thus, at time t ₀ ~t _1, the basic torque (constant value) is determined as a final target torque (step S5 in FIG. 3). Further, the ignition timing of the ignition plug 5c is set to an ignition timing for generating a basic torque.

Next, at time t ₁ in FIG. 8, the driver starts the steering, the steering angle and the steering speed (absolute value of) increases. When the steering speed becomes _{equal to} or higher than T _s1 , in the flowchart shown in FIG. 4, the processing of steps S21 → S23 → S24 → S25 → S26 → return is repeated, so that the additional acceleration and the increased torque are set. That is, in step S24 of FIG. 4, the additional acceleration is set using the map shown in FIG. 5, and in step S25, the increased torque required to realize the set additional acceleration is calculated. In the example shown in FIG. 8, at time t ₁ ~t _2, since the driving operation of depressing of the accelerator pedal is not being performed, the values in the value of the basic torque is constant (time t ₀ ~t ₁ Has not changed).

Thus, at time t ₁ ~t _2, is set increased torque corresponding to the set additional acceleration, the final target torque obtained by adding the increased torque to the basic torque (constant value) is set. Further, the actuator control amount set in step S6 of FIG. 3 is used to generate a final target torque in which the increased torque is added to the basic torque. Specifically, in the present embodiment, as shown at the bottom of FIG. 8, the ignition timing of the ignition plug 5c is advanced more than the ignition timing for generating the basic torque.

The increase in torque due to the addition of the increased torque starts rising within about 50 msec after the steering speed reaches T _s1 (after the processing of step S24 and subsequent steps is performed in the flowchart of FIG. 4) The maximum value is reached in about 200 to about 250 msec. When the drive torque of the rear wheel 2b rises based on this increased torque, a force that causes the vehicle 1 to lean forward (submerges the front side of the vehicle) via the suspension 3 instantaneously acts, and the front wheel 2a that is a steering wheel Load increases. Due to the increase in the load on the front wheels 2a that rise instantaneously, the responsiveness of the vehicle to the steering operation and the linear feeling are improved.

  On the other hand, an increase in the driving torque of the rear wheel 2b based on the increased torque accelerates the vehicle 1 and generates a force that causes the vehicle 1 to lean backward (submerge the rear side of the vehicle) by this acceleration. However, after the driving torque starts to increase, the vehicle 1 is accelerated, and there is a certain time lag until the acceleration substantially tilts the vehicle 1 backward. For this reason, the decrease in the load on the front wheels 2a due to the acceleration of the vehicle 1 has little effect on the vehicle responsiveness and the linear feeling to the steering operation.

In addition, the time chart of the increased torque in FIG. 8 shows the increased torque in the first vehicle equipped with a tire having a certain vertical spring constant as a solid line, and shows the second vehicle equipped with a tire having a smaller vertical spring constant than this vehicle. The increased torque in the vehicle _{No. 2} is indicated by a two-dot chain line (time t1 to t2 in FIG. 8). However, the first vehicle and the second vehicle are different only in the vertical spring constant of the mounted tire, and the other parameters are the same. As described above, when the vertical spring constant of the tire mounted on the vehicle is small, the value of the increase torque is set larger for the same additional deceleration than when the vertical spring constant is large.

  In this embodiment, when the vertical spring constant of the tire mounted on the vehicle 1 is small, the value of the increased torque is set to be larger than when the vertical spring constant is large. The rate of increase [Nm / sec] of the torque per unit time can be set large. That is, when the vertical spring constant of the tire mounted on the vehicle 1 is small, the basic torque can be strongly increased by setting the increase rate of the increased torque per unit time to be large. As described above, when the increasing rate of the increasing torque per unit time is set to a large value, the increasing torque sharply increases, so that the force for instantaneously increasing the front wheel load can be increased, and the longitudinal spring constant of the tire is small. However, the vehicle responsiveness and the linear feeling can be improved.

Then, shifting to steering holding at time t ₂ in FIG. 8, the steering angle is a constant value. At time t ₂ ~t ₃ in FIG. 8, in the flowchart of FIG. 4, the process of step S21 → S22 → return is repeated. In the example shown in FIG. 8, at time t ₂ ~t _3, since the driving operation of depressing of the accelerator pedal is not being performed, the values in the value of the basic torque is constant (time t ₀ ~t ₁ Has not changed). Thus, at time t ₂ ~t _3, since the steering speed is zero, the value of the additional acceleration is also zero. Accordingly, the advance of the ignition timing for increasing the basic torque by the increased torque is also set to zero.

Further, when the driver starts to switch back steering 6 at time t ₃ in FIG. 8, the steering angle (absolute value of) begins to decrease, in the flowchart of FIG. 4, step S21 → S22 → S27 → S28 → S29 → The process of S30 is repeated. In this state, an additional deceleration is set in step S28 with a decrease in the steering angle. Thus, at time t ₃ ~t _4, reduction torque for realizing the additional deceleration set in step S28 is set. In the example shown in FIG. 8, the time chart of the reduced torque indicates the increased torque in the first vehicle equipped with the tire having a certain vertical spring constant by a solid line, and the tire having the vertical spring constant smaller than this vehicle. It is shown in chain lines increasing torque a point in the second vehicle equipped with a (time t ₃ ~t ₄ in FIG. 8). As described above, when the vertical spring constant of the tire mounted on the vehicle is small, the value of the reduced torque is set to be larger for the same additional deceleration than when the vertical spring constant is large. At time t ₃ ~t _4, since the driving operation of depressing of the accelerator pedal is not being performed, the value of the basic torque is constant, the final target torque obtained by subtracting the reduced torque from the basic torque (constant value) is set You. In addition, the actuator control amount set in step S6 of FIG. 3 is used to generate a final target torque obtained by subtracting the reduced torque from the basic torque. Specifically, in the present embodiment, as shown at the bottom of FIG. 8, the ignition timing of the ignition plug 5c is retarded from the ignition timing for generating the basic torque.

Then, the (steering speed = 0) the steering angle is fixed steering returns to 0 at time t ₄ in FIG. 8, in the flowchart of FIG. 4, so that the process of step S21 → S22 → return is repeated. When the steering speed becomes 0, the values of the additional acceleration and the additional deceleration also become 0, and the value of the basic torque is determined as the final target torque.

  In the example shown in FIG. 8, the value of the basic torque is a fixed value. However, if the basic torque changes due to the operation of the accelerator pedal or the like by the driver, the increased torque is added to the basic torque. Or the reduced torque is subtracted. However, since the time from turning of the steering wheel 6 by the driver to holding and turning back is generally a relatively short time (usually less than 1 to 2 seconds), the basic torque during this period is considered to be constant. You can also.

Next, a method of manufacturing the vehicle control system according to the embodiment of the present invention will be described with reference to FIG.
FIG. 9 is a flowchart of a manufacturing procedure in the manufacturing method of the vehicle control system according to the embodiment of the present invention.

  First, in step S41 of FIG. 9, as a step of preparing a controller, a PCM 14, which is a controller for controlling the engine 4 of the vehicle 1, is prepared. As described above, the PCM 14 includes an accelerator opening sensor 10 that is a driving state sensor that detects a driving state of the vehicle 1, a steering angle sensor 8 that detects a steering angle of a steering device 7 mounted on the vehicle 1, and an accelerator The engine 4 is controlled based on the detection signal of the opening degree sensor 10 and the detection signal of the steering angle sensor 8.

  In step S42, as a step of preparing tires, tires to be mounted as front wheels 2a, which are the steered wheels of the vehicle 1, are prepared. Next, in step S43, the tire prepared in step S42 is assembled to the vehicle body of the vehicle 1.

  Next, in step S44, it is determined whether the vertical spring constant of the tire assembled in step S43 is smaller than a predetermined vertical spring constant. If it is smaller than the predetermined vertical spring constant, the process proceeds to step S45, and if it is not smaller than the predetermined vertical spring constant, the process proceeds to step S46. Alternatively, as a modified example, the present invention is configured such that when the rim diameter of the tire assembled in step S43 is smaller than a predetermined value, the process proceeds to step S45, and when the rim diameter is equal to or larger than the predetermined rim diameter, the process proceeds to step S46. You can also.

  In step S45, as a first parameter setting step, the tire longitudinal spring correction coefficient K1 corresponding to the tire assembled in the vehicle body of the vehicle 1 in step S43 is stored in the parameter storage unit 23 of the PCM 14 as a control parameter.

On the other hand, if it is determined in step S44 that the vertical spring constant of the tire assembled in step S43 is equal to or greater than the predetermined vertical spring constant, the process proceeds to step S46, and step S46, which is a second parameter setting step, is performed. Is executed. In step S46, the tire longitudinal spring correction coefficient K1 corresponding to the tire assembled in the vehicle body of the vehicle 1 in step S43 is stored in the parameter storage unit 23 of the PCM 14. The tire vertical spring correction coefficient K1 stored in step S46 is set to a value smaller than the tire vertical spring correction coefficient K1 stored in step S45.
As described above, it is possible to manufacture a vehicle control system in which the tire vertical spring correction coefficient K1 as a control parameter is set according to the vertical spring constant of a tire assembled as a standard specification in the vehicle 1.

  According to the vehicle control method of the embodiment of the present invention, the increase torque is set so as to increase the basic torque based on the increase in the steering angle of the steering device 7 mounted on the vehicle 1, and the front wheel load increases. Therefore, it is possible to improve the vehicle responsiveness and the linear feeling to the steering operation. Further, when the longitudinal spring constant of the tire mounted on the vehicle 1 is small, the increased torque can be changed so that the basic torque is increased more than when the longitudinal spring constant is large (step S26 in FIG. 4). ). Thereby, even when the vertical spring constant of the tire of the vehicle 1 is small, the vehicle responsiveness and the linear feeling can be sufficiently improved.

  According to the vehicle control method of the present embodiment, when the longitudinal spring constant of the tire is small, the basic torque is increased by increasing the value of the increased torque (FIG. 6). The vehicle response and the linearity can be sufficiently improved even when the longitudinal spring constant is small.

  Further, according to the vehicle control method of the present embodiment, when the vertical spring constant of the tire is small, the basic torque is more strongly reduced than when the vertical spring constant is large (step S30 in FIG. 4). As a result, the load on the front wheels 2a, which are the steered wheels, can be sufficiently reduced, and the responsiveness of the vehicle to turning back of the steering wheel 6 can be improved.

  The preferred embodiment of the present invention has been described above, but various changes can be made to the above-described embodiment. In particular, in the above-described embodiment, the present invention is applied to a vehicle equipped with a gasoline engine. However, the present invention can be applied to a vehicle equipped with various motors such as a diesel engine and an electric motor.

1 vehicle 2a front wheel (steering wheel)
2b Rear wheel (drive wheel)
3 Suspension 4 Engine (motor)
5a Throttle valve 5b Injector 5c Spark plug 5d Variable valve mechanism 6 Steering wheel 7 Steering device 8 Steering angle sensor 10 Accelerator opening sensor (driving state sensor)
12 vehicle speed sensor 14 PCM (controller)
16 Basic torque setting unit 18 Increasing torque setting unit 20 Decreasing torque setting unit 22 Engine control unit 23 Parameter storage unit

Claims (5)

A vehicle control system that controls a vehicle whose rear wheels are driven by a prime mover,
A driving state sensor for detecting a driving state of the vehicle,
A steering angle sensor that detects a steering angle of a steering device mounted on the vehicle,
A controller that controls the prime mover based on the detection signal of the driving state sensor and the detection signal of the steering angle sensor,
The controller is
Based on the detection signal of the operating state sensor, set a basic torque to be generated by the prime mover,
When an increase in the steering angle is detected by the steering angle sensor, an increase torque is set so as to increase the basic torque,
It is configured to control the prime mover such that a torque obtained by adding the increased torque to the basic torque is generated,
The controller is configured to be able to change the increased torque so that when the longitudinal spring constant of the tire mounted on the vehicle is small, the basic torque is increased more than when the longitudinal spring constant is large. A vehicle control system.   The controller increases the rate of increase of the increased torque per unit time when the longitudinal spring constant of the tire mounted on the vehicle is smaller than when the longitudinal spring constant is large, thereby reducing the basic torque. 2. The vehicle control system according to claim 1, wherein the number is increased.   The controller increases the basic torque by setting the value of the increasing torque to be larger when the longitudinal spring constant of the tire mounted on the vehicle is small than when the longitudinal spring constant is large. 3. The vehicle control system according to 1 or 2. The controller sets a reduced torque such that the basic torque is reduced based on a decrease in a steering angle of a steering device mounted on the vehicle, and calculates a torque obtained by subtracting the reduced torque from the basic torque. Configured to control the prime mover to occur,
The controller is configured to be capable of changing the reduced torque so that when the longitudinal spring constant of the tire mounted on the vehicle is small, the basic torque is reduced more strongly than when the longitudinal spring constant is large. The vehicle control system according to any one of claims 1 to 3, wherein: A method for manufacturing a vehicle control system that controls a vehicle whose rear wheels are driven by a prime mover,
A driving state sensor that detects a driving state of the vehicle, a steering angle sensor that detects a steering angle of a steering device mounted on the vehicle, and a detection signal of the driving state sensor and a detection signal of the steering angle sensor. Providing a controller for controlling the prime mover;
Preparing a tire to be mounted as a steering wheel of the vehicle,
The controller is
Based on the detection signal of the operating state sensor, set a basic torque to be generated by the prime mover,
When an increase in the steering angle is detected by the steering angle sensor, an increase torque is set so as to increase the basic torque,
It is configured to control the prime mover such that a torque obtained by adding the increased torque to the basic torque is generated,
Further, when a tire with a small vertical spring constant is mounted on the vehicle, the control parameters of the controller are set so that the basic torque is increased more than when a tire with a large vertical spring constant is mounted. Parameter setting process to be performed,
A method for manufacturing a vehicle control system, comprising:

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