Vehicle control system

Abstract

Vehicle control system, including: a detector (5) that detects an actuation quantity of an accelerator (4) and a speed of a vehicle (Ve); and a controller (6) that is configured to to set an acceleration property that determines a relationship between a target acceleration, the amount of actuation of the accelerator (4) and the speed of the vehicle (Ve), to calculate the target acceleration in relation to the amount of actuation of the accelerator (4) or the speed of the vehicle (Ve) based on the acceleration property, to control the acceleration of the vehicle (Ve) based on the calculated target acceleration, to select a driving mode of the vehicle (Ve) from a normal mode, in which a first acceleration property is used as a standard acceleration property, and a sport mode, in which a second acceleration property is used to propel the vehicle (Ve) in a dynamic manner, characterized by the fact that: the controller (6) is further configured to to increase the target acceleration in accordance with an increase in the amount of actuation of the accelerator (4) at a first rate of change and to decrease the target acceleration in accordance with an increase in the speed of the vehicle (Ve) at a second rate of change when the first acceleration feature is used in normal mode, and to increase the target acceleration in accordance with an increase in the amount of actuation of the accelerator (4) at the first rate of change and to decrease the target acceleration in accordance with an increase in the speed of the vehicle (Ve) at a third rate of change which is smaller than the second rate of change when the second acceleration feature is used in the sport mode.

Description

Cross-reference to related applications

[0001] The present disclosure claims the teachings of application JP 2018 - 199 180 filed with the Japanese Patent Office on October 23, 2018, the disclosure of which is incorporated herein by reference in its entirety. Background Area of ​​Revelation

[0002] Embodiments of the present application relate to the teaching of a vehicle control system configured to set a target acceleration based on an acceleration operation performed by a driver. Discussion about the state of the art

[0003] US 2015 / 0 019 091 A1 describes a vehicle control system configured to set a target acceleration based on an accelerator angle. The vehicle control system taught in US 2015 / 0 019 091 A1 is capable of selectively setting either a normal mode or a sport mode as the vehicle driving mode. A difference between the sport mode target acceleration and the normal mode target acceleration decreases with increasing vehicle speed when compared under the same conditions with respect to the accelerator angle. A target acceleration is calculated based on target acceleration characteristics, and an output torque of an engine is controlled based on the target acceleration and a gear ratio of a transmission connected to the engine.

[0004] According to the teaching of US 2015 / 0 019 091 A1, a sport mode target acceleration is greater than a normal mode target acceleration, and as described, the difference between the sport mode target acceleration and the normal mode target acceleration becomes smaller as the vehicle speed increases. For these reasons, it is possible to improve vehicle acceleration performance during sport mode to respond to the driver's aggressive intention to further accelerate the vehicle while suppressing deterioration in fuel consumption performance in sport mode. However, according to the teaching of US 2015 / 0 019 091 A1, the driver's intention cannot be properly realized in sport mode. As described, in the teaching of US 2015 / 0 019 091 A1, the target acceleration characteristics in each driving mode are adjusted according to the accelerator angle.This means that the target acceleration differs in relation to the accelerator angle in normal mode and sport mode. For this reason, as shown in . Fig. 1, an increasing rate of the target acceleration in the sport mode in a certain condition (for example, less than 100 km / h) is smaller than in the normal mode within the range R. In the range R, therefore, the acceleration of the vehicle in the sport mode is increased gently even though the driver selects the sport mode to accelerate the vehicle sharply.

[0005] DE 11 2011 104 894 T5 and DE 11 2011 105 844 T5 each relate to a system for controlling a vehicle based on the accelerator pedal stroke. Description

[0006] Aspects of the present disclosure have been conceived with reference to the aforementioned technical problems, and therefore, it is an object of the present invention to provide a vehicle control system configured to operate a vehicle in accordance with a driver's intention in respective driving modes such as a normal mode and a sport mode.

[0007] The vehicle control system according to the embodiment of the present invention includes a detector that detects an operation amount of an accelerator and a speed of a vehicle, and a controller that controls the vehicle.The controller is configured to: set an acceleration characteristic that determines a relationship between a target acceleration, the operation amount of the accelerator, and the speed of the vehicle; calculate the target acceleration with respect to the operation amount of the accelerator or the speed of the vehicle based on the acceleration characteristic; control an acceleration of the vehicle based on the calculated target acceleration; and select a driving mode of the vehicle from a normal mode in which a first acceleration characteristic is used as a standard acceleration characteristic and a sport mode in which a second acceleration characteristic is used to drive the vehicle in a dynamic manner.To achieve the above-described object, the controller according to the embodiment of the present invention is further configured to: increase the target acceleration in accordance with an increase in the operation amount of the accelerator at a first change rate and decrease the target acceleration in accordance with an increase in the speed of the vehicle at a second change rate when the first acceleration characteristic is used in the normal mode; and increase the target acceleration in accordance with an increase in the operation amount of the accelerator at the first change rate and decrease the target acceleration in accordance with the speed of the vehicle at a third change rate that is smaller than the second change rate when the second acceleration characteristic is used in the sport mode.

[0008] In one non-limiting embodiment, the controller may be further configured to: in a high acceleration range higher than a reference acceleration value, decrease the target acceleration in accordance with an increase in the speed of the vehicle at a fourth rate of change that is smaller than the second rate of change, and in a low acceleration range lower than the reference acceleration value, decrease the target acceleration in accordance with an increase in the speed of the vehicle at a fifth rate of change that is greater than the fourth rate of change when the first acceleration characteristic is used in the normal mode;and in the high acceleration range, decrease the target acceleration in accordance with an increase in the speed of the vehicle at a sixth rate of change that is smaller than the third rate of change, and in the low acceleration range, decrease the target acceleration in accordance with an increase in the speed of the vehicle at a seventh rate of change that is greater than the sixth rate of change when the second acceleration characteristic is used in the sport mode;

[0009] In one non-limiting embodiment, the controller may be further configured to: in a low speed range that is lower than a lower limit speed, decrease the target acceleration in accordance with an increase in the speed of the vehicle at an eighth rate of change that is greater than the second rate of change; in a medium speed range that is higher than the lower limit speed but lower than the upper limit speed, decrease the target acceleration in accordance with an increase in the speed of the vehicle at a ninth rate of change that is less than the eighth rate of change; and in a high speed range that is higher than the upper limit speed, decrease the target acceleration in accordance with an increase in the speed of the vehicle at a tenth rate of change that is greater than the ninth rate of change.when the first acceleration characteristic is used in the normal mode; and in the low speed range, to decrease the target acceleration in accordance with an increase in the speed of the vehicle at an eleventh rate of change that is greater than the third rate of change, in the medium speed range, to decrease the target acceleration in accordance with an increase in the speed of the vehicle at a twelfth rate of change that is smaller than the eleventh rate of change, and in the high speed range, to decrease the target acceleration in accordance with an increase in the speed of the vehicle at a thirteenth rate of change that is greater than the twelfth rate of change when the second acceleration characteristic is used in the sport mode.

[0010] Thus, according to at least one embodiment of the present invention, the driving mode of the vehicle to which the vehicle control system is applied can be selected from the normal mode as the standard mode and the sport mode in which the vehicle is driven in a dynamic manner. When the first acceleration characteristic is used in the normal mode, the target acceleration is increased in accordance with an increase in the operation amount of the accelerator at the first change rate, and the target acceleration is decreased in accordance with an increase in the vehicle speed at the second change rate. Therefore, in the normal mode, the target acceleration can be sensitively decreased in accordance with an increase in the vehicle speed compared to the sport mode. That is, provided the accelerator is operated by a predetermined amount, the target acceleration is immediately reduced to zero.When the target acceleration is reduced to zero in this way, the vehicle is driven at a constant speed by maintaining the accelerator operation amount, and the vehicle speed is changed in accordance with the change in the accelerator operation amount. That is, in the normal mode, the vehicle speed is determined by setting the accelerator operation amount. Therefore, in the normal mode, the driver can easily control the vehicle speed by operating the accelerator.

[0011] Whereas, when the second acceleration characteristic is used in the sport mode, the target acceleration is increased in accordance with an increase in the accelerator operation amount at a first change rate, but the target acceleration is decreased in accordance with an increase in the vehicle speed at the third change rate, which is smaller than the second change rate. As described, the rate of increase of the target acceleration with respect to an increase in the accelerator operation amount is not changed even when the driving mode is switched between the normal mode and the sport mode. That is, the sensitivity of the target acceleration with respect to the accelerator operation amount is not changed even when the driving mode is changed.Therefore, in Sport mode, the vehicle can be driven dynamically while preventing the driver from feeling uncomfortable when switching the driving mode from Normal mode to Sport mode. Furthermore, in Sport mode, the sensitivity of the target acceleration to the vehicle speed is reduced compared to Normal mode. Therefore, the target acceleration is slightly reduced even when the vehicle speed increases. That is, the target acceleration greatly depends on the amount of accelerator operation. In Sport mode, when the accelerator is operated by the driver in a predetermined amount to accelerate the vehicle, the target acceleration is continuously set greater than zero, so that the vehicle is slightly accelerated. Therefore, in Sport mode, the driver can easily control the longitudinal acceleration of the vehicle by operating the accelerator.

[0012] Therefore, the speed of the vehicle can be easily controlled in the normal mode by operating the accelerator, and the acceleration of the vehicle can be easily controlled in the sport mode by operating the accelerator. Furthermore, in the sport mode, the acceleration can be easily changed dynamically in response to an operation of the accelerator. Therefore, according to the embodiment of the present invention, the vehicle can be operated in each driving mode in accordance with the driver's intention.

[0013] According to another embodiment of the present invention, in both the normal mode and the sport mode, the rate of change (i.e., the reduction rate) of the target acceleration is increased in accordance with an increase in the vehicle speed in the low acceleration range and reduced in the high acceleration range. Therefore, according to another embodiment, the speed of the vehicle can be easily controlled in the low acceleration range, and the acceleration of the vehicle can be easily controlled in the high acceleration range. For these reasons, the vehicle can be operated in accordance with the driver's intention based on the target acceleration.

[0014] In the low-speed range, it is necessary to easily control the vehicle speed in order to smoothly start or accelerate the vehicle. To this end, according to yet another embodiment, the rate of change (i.e., the reduction rate) of the target acceleration is increased with respect to an increase in the vehicle speed in the low-speed range, regardless of the selected driving mode. In the medium-speed range, the vehicle is frequently accelerated and decelerated. Therefore, in order to easily control the acceleration, the reduction rate of the target acceleration is reduced with respect to an increase in the vehicle speed in the medium-speed range. The vehicle is driven at a high speed when traveling on an expressway, for example.Therefore, in the high-speed range, the reduction rate of the target acceleration is also increased relative to the increase in vehicle speed to easily control the vehicle speed. For these reasons, the vehicle can be operated in accordance with the driver's intention depending on the driving condition and vehicle speed. Brief description of the drawings

[0015] Features, aspects, and advantages of exemplary embodiments of the present disclosure will be better understood from the following description and the accompanying drawings, which are not intended to limit the invention in any way. Fig. 1 is a graph showing increasing target acceleration in Sport and Normal modes according to the prior art; Fig. 2 is a schematic diagram showing an example of a structure of the vehicle to which the control system according to the embodiment of the present invention is applied; Fig. 3 is a map determining the target acceleration with respect to a position of an accelerator pedal in the normal mode at the first change rate; Fig. 4 is a map showing the target determination with respect to a vehicle speed in the normal mode at the second change rate; Fig. 5 is a time chart showing temporal changes in the acceleration and speed of the vehicle in the normal mode in which the first acceleration characteristic is used; Fig. 6 is a map determining the target acceleration with respect to a position of the accelerator pedal in the sport mode at the first change rate; Fig. 7 is a map determining the target acceleration with respect to a vehicle speed in the sport mode at the third change rate; Fig. 8 is a time chart showing temporal changes in the acceleration and speed of the vehicle in the sport mode in which the second acceleration characteristic is used; Fig. 9 is a map of characteristics for changing the reduction rate of the target acceleration in a high acceleration range and a low acceleration range; and Fig. 10 is a map of characteristics for changing the reduction rate of the target acceleration in a low speed range, a medium speed range, and a high speed range. Detailed description of the preferred embodiment(s)

[0016] Embodiments of the present invention will now be explained with reference to the accompanying drawings. It should be noted that the embodiments illustrated below are merely examples of the present invention and do not limit the scope of the present invention.

[0017] With reference to Fig. 2, an example of a drive system of a vehicle Ve is shown, to which the control system according to the embodiment of the present invention is applied. Fig. The vehicle Ve shown in Figure 2 has a drive motor (in Fig. 1 referred to as “PWR”) 1, a pair of front wheels 2, a pair of rear wheels 3, an accelerator pedal 4, a detector 5 and a controller (in Fig. 1 referred to as “ECU”) 6.

[0018] The drive motor 1 generates drive torque to produce a driving force for driving the vehicle Ve. For example, an internal combustion engine such as a gasoline engine or a diesel engine can be used as the drive motor 1. An output of the engine can be electrically adjusted, and the engine can be electrically started and stopped as needed. Provided that the gasoline engine is used as the drive motor 1, an opening degree of a throttle valve, an amount of fuel supply or fuel injection, a start and end of ignition, an ignition timing, etc. can be electrically controlled. Otherwise, provided that the diesel engine is used as the drive motor 1, an amount of fuel injection, an ignition timing, an opening degree of a throttle valve of an EGR (Exhaust Gas Recirculation) system, etc. can be electrically controlled.

[0019] Furthermore, a permanent magnet synchronous motor and an induction motor can be used as the drive motor 1. These types of motors can not only serve as a motor for generating torque when driven by the electricity supplied to them, but also as a generator for generating electricity when rotated with torque applied to them. That is, a motor-generator can also be used as the drive motor 1. In this case, the drive motor 1 is switched between a motor and a generator by electrically controlling the drive motor 1, and an output speed and output torque of the drive motor 1 can be electrically controlled.

[0020] In the Fig. In the vehicle Ve shown in Fig. 2, the front wheels 2 serve as drive wheels, and a drive torque generated by the drive motor 1 is transmitted to the front wheels 2 to drive the vehicle Ve. However, the vehicle control system according to the embodiment of the present invention can also be applied to a rear-wheel drive vehicle in which the rear wheels serve as drive wheels, and to a four-wheel drive vehicle in which all wheels are driven by the torque of the drive motor 1. In a case of using the engine as the drive motor 1, a transmission may be arranged downstream of the drive motor 1 to transmit the output torque of the drive motor 1 to the drive wheels via the transmission.

[0021] The vehicle Ve is accelerated in accordance with an operation amount of an accelerator and a vehicle speed. To this end, the vehicle control system controls an output of the drive motor 1 so as to achieve a target acceleration set based on an operation amount of an accelerator and a vehicle speed. Specifically, in the vehicle Ve, an acceleration operation is performed by depressing the accelerator pedal 4, and the drive torque generated by the drive motor 1 is increased in accordance with a position of the accelerator pedal 4. In other words, the drive torque generated by the drive motor 1 is increased in response to an increase in depression of the accelerator pedal 4, thereby increasing the drive force for driving the vehicle Ve.In contrast, the drive torque generated by the drive motor 1 is reduced by reversing the accelerator pedal 4. In other words, the drive torque generated by the drive motor 1 is reduced in response to a reduction in depression of the accelerator pedal 4, thereby reducing the driving force for driving the vehicle Ve. Given that the engine is employed as the drive motor 1, an engine braking force derived from a friction torque and a pumping loss is applied to the vehicle Ve when the accelerator pedal 4 is reversing. In contrast, given that the motor-generator is employed as the drive motor 1, a regenerative braking force derived from a regenerative torque of the motor-generator is applied to the vehicle Ve when the accelerator pedal 4 is reversing.

[0022] Thus, the acceleration of the vehicle Ve is controlled by operating the accelerator pedal 4 to adjust the driving force and braking force. For this purpose, the accelerator pedal 4 is provided with an accelerator position sensor 5a for detecting a position (i.e., depression) and operating speed of the accelerator pedal 4. By detecting an operating speed of the accelerator pedal 4, an operating direction of the accelerator pedal 4 can be estimated. That is, it is possible to determine whether the accelerator pedal 4 is being depressed or released by the driver.

[0023] The detector 5 collects data on the state of the vehicle Ve. Specifically, the detector 5 includes: the aforementioned accelerator position sensor 5a, which detects, for example, a position of the accelerator pedal 4; a wheel speed sensor 5b, which detects a speed of the vehicle Ve; a brake stroke sensor 5c, which detects an operation amount (i.e., a depression or a stroke) of a brake pedal (not shown); an acceleration sensor 5d, which detects a longitudinal acceleration of the vehicle Ve; and a speed sensor 5e, which detects a rotational speed of a drive shaft (not shown) of the drive motor. The detector 5 is electrically connected to an aforementioned controller 6, so that detection values ​​obtained from these sensors are transmitted to the controller 6 in the form of an electrical signal.

[0024] Specifically, the controller 6 is an electronic control unit including a microcomputer. To control the vehicle Ve, the data collected by the detector 5 is sent to the controller 6, and the controller 6 performs a calculation using the event data from the detector 5 as well as the data and formulas stored in advance. Calculation results are transmitted from the controller 6 in the form of a control signal.

[0025] The controller 6 has a calculation section 6a and a control section 6b. For example, a position of the accelerator pedal 4 as an operation amount of the accelerator detected by the accelerator position sensor 5a and a vehicle speed detected by the wheel speed sensor 5b are sent to the calculation section 6a, and the calculation section 6a calculates a target acceleration and a target drive torque Ve of the vehicle based on the data transmitted from these sensors. On the other hand, the control section 6b controls the longitudinal acceleration of the vehicle in accordance with the position of the accelerator pedal 4 so as to achieve the target acceleration calculated by the calculation section 6a. Specifically, the control section 6b transmits control signals for controlling the drive force and the braking force to achieve the target acceleration calculated by the calculation section 6a.

[0026] Thus, the controller 6 sets a target acceleration based on a depression of the accelerator pedal 4 and controls a driving force and a braking force to achieve the target acceleration. Although in Fig. 2 only one controller 6 is shown, a plurality of controllers can be arranged in the vehicle Ve to control the specific devices individually.

[0027] A driving mode of the vehicle Ve, to which the vehicle control system according to the embodiment of the present invention is applied, can be selected from at least a normal mode or a standard mode in which the vehicle Ve is accelerated in a normal manner, and a dynamic mode or a sport mode in which the vehicle Ve is accelerated in a dynamic manner. To select the driving mode, the vehicle Ve is provided with a selection device, such as a select switch or a select lever (neither of which is shown), which is operated by the driver to select the driving mode. The driving mode of the vehicle Ve can also be automatically switched by the controller 6 among a variety of modes, including the normal mode and the sport mode.That is, in the vehicle Ve, a selection mode of the driving mode can be selected from a manual mode in which the driving mode is manually selected by the driver and an automatic mode in which the driving mode is automatically selected by the controller 6.

[0028] The controller 6 is configured to drive a vehicle in accordance with the driver's intention in each driving mode, such as the normal mode and the sport mode. For this purpose, the controller 6 changes the acceleration characteristic between the normal mode and the sport mode. Specifically, in the normal mode, the controller 6 uses a first acceleration characteristic as a default characteristic, and in the sport mode, the controller 6 uses a second acceleration characteristic to drive the vehicle in a dynamic manner.

[0029] The acceleration characteristic is subject to the amount of accelerator operation, the vehicle speed, and the target acceleration. For example, the acceleration characteristic can be determined by a predetermined formula, a control map, a control table, etc. By changing the acceleration characteristic, it is possible to change the driving feel of the vehicle Ve.

[0030] The vehicle control system according to the embodiment of the present invention can be applied to vehicles in which the acceleration is changed by operating an accelerator pedal, a throttle lever, a throttle grip, etc. In particular, the Fig. 2 is accelerated by depressing an accelerator pedal 4. In other words, the vehicle Ve shown in Fig. 2 accelerates the vehicle Ve in accordance with a position of the accelerator pedal 4.

[0031] As described, in the normal mode, the controller 6 uses the first acceleration characteristic as a standard acceleration characteristic. In a case where the first acceleration characteristic is used, a target acceleration is increased in accordance with an increase in the depression of the accelerator pedal 4 at a first rate of change and is decreased in accordance with an increase in a vehicle speed at a second rate of change. Specifically, the first acceleration characteristic is set with respect to the Fig. 3 and Fig. 4 shown characteristic curve fields.

[0032] In particular, Fig. 3 shows a characteristic field that determines the target acceleration in relation to the position of the accelerator pedal 4 in the normal mode at a first rate of change. In Fig. 3, line L1 shows a relationship between the target acceleration and the position of the accelerator pedal 4, assuming that the vehicle speed is a1. Line L2 shows a relationship between the target acceleration and the position of the accelerator pedal 4, assuming that the vehicle speed is b1. Line L3 shows a relationship between the target acceleration and the position of the accelerator pedal 4, assuming that the vehicle speed is c1. Here, the vehicle speed b1 is faster than the vehicle speed c1 (b1>a1>c1). As can be seen from Fig. As can be seen from Figure 3, the slopes of the lines L1, L2 and L3 (i.e. the first rate of change) are identical to each other.

[0033] In case the first acceleration property is used in the normal mode, as in Fig. 3, the target acceleration is increased in accordance with an increase in the depression of the accelerator pedal 4 at a first rate of change. Specifically, the first rate of change is a rate of change in the amount of a position of the accelerator pedal 4 to change the amount of target acceleration, and in Fig. 3, the first change rate is indicated as a slope of each of the lines L1, L2, and L3. According to the embodiment of the present invention, the relationship between the change amount of a position of the accelerator pedal 4 and the change amount of the target acceleration is set to a first change rate as a fixed rate. That is, the target acceleration is increased in accordance with an increase in the depression of the accelerator pedal 4 at a first change rate in both the normal mode and the sport mode. In other words, an increasing rate of the target acceleration with respect to an increase in the depression of the accelerator pedal 4 is not changed even when the driving mode is switched between the normal mode and the sport mode.

[0034] The second change rate used in the normal mode is greater than a third change rate mentioned below, which is selected in the sport mode. In other words, a slope of each line representing the change rate in the following Fig. 4, individually steeper than a slope of each line indicating the third rate of change in the following mentioned Fig. 7. Therefore, the Fig. 3 between the lines L1 and L2 and between the lines L1 and L3 are wider than those shown in the following Fig. 6 shown distances between lines L7 and L8 or lines L7 and L9.

[0035] Fig. 4 is a map of characteristics that determines the target acceleration with respect to the vehicle speed Ve in the normal mode at the second rate of change. Fig. 4, in particular, line L4 shows a relationship between the target acceleration and the vehicle speed, provided that the accelerator pedal 4 is positioned at a position A1, line L5 shows a relationship between the target acceleration and the vehicle speed, provided that the accelerator pedal 4 is positioned at a position B1, and line L6 shows a relationship between the target acceleration and the vehicle speed, provided that the accelerator pedal 4 is positioned at a position C1. Here, depression of the accelerator pedal 4 at position A1 is less than depression of the accelerator pedal 4 at position B1, and depression of the accelerator pedal 4 at position B1 is less than depression of the accelerator pedal 4 at position C1 (A1 <B1 <C1). Wie aus Fig. As can be seen from Figure 4, the slopes of lines L4, L5 and L6 (i.e. the second rate of change) are identical to each other.

[0036] In the case of reducing the target acceleration in the normal mode, as in Fig. 4, the target acceleration is decreased at the second rate of change in accordance with an increase in the vehicle speed. Specifically, the second rate of change is a ratio of a change in the vehicle speed to a change in the target acceleration, and Fig. 4, the second change rate is displayed as a slope of each of the lines L4, L5, and L6. According to the embodiment of the present invention, the relationship between the amount of change in the vehicle speed and the amount of change in the target acceleration is changed depending on the selected driving mode. Specifically, the second change rate is used to decrease the target acceleration in the normal mode, whereby the third change rate, which is smaller than the second change rate, is used to decrease the target acceleration in the sport mode. That is, the third change rate for decreasing the target acceleration with respect to an increase in the vehicle speed is smaller than the second change rate. In other words, a slope of each line showing the second change rate in Fig. 4, individually steeper than a slope of each line indicating the third rate of change in Fig. 7 displays.

[0037] Thus, according to the embodiment of the present invention, each of the lines L1, L2, L3, L4, L5 and L6 indicating the first acceleration characteristic are plotted in the Fig. 3 and Fig. 4. However, the first acceleration characteristic can be changed to vary the target acceleration in a quadratic, logarithmic, or stepwise manner. The first acceleration characteristic can also be determined by a functional formula that defines a relationship between the target acceleration and the depression of the accelerator pedal or the vehicle speed. Instead, the first acceleration characteristic can also be determined by a control table that defines a relationship between the target acceleration and the depression of the accelerator pedal or the vehicle speed.

[0038] With reference to Fig. 5, the acceleration and speed of the vehicle Ve are shown, which are changed in the normal mode in which the values ​​set in the Fig. 3 and Fig. 4 is used. Before point t11, the accelerator pedal 4 is positioned at position A1. The accelerator pedal 4 is depressed by the driver at point t11 ​​such that the position of the accelerator pedal 4 is changed to position B1 at point t12. Consequently, the target acceleration is increased such that the acceleration of the vehicle Ve is increased from point t11 ​​to point t12, and the speed of the vehicle Ve is increased from a1 to b1 during a period from point t11 ​​to point t13. The accelerator pedal 4 is held in position B1 after point t12. When the speed of the vehicle Ve is increased, as indicated by the arrows in Fig. 3 and Fig. 4, the target acceleration is reduced to zero. Therefore, the vehicle's speed Ve stabilizes after point t13.

[0039] Thus, in the normal mode, in which the first acceleration characteristic is used, the vehicle Ve can be driven at the speed b1 by maintaining the position of the accelerator pedal 4 at the position B1 after the accelerator pedal 4 is depressed from the position A1. That is, in the normal mode, the speed of the vehicle Ve is determined by fixing the position of the accelerator pedal 4. This means that the vehicle speed depends more on the position of the accelerator pedal 4 than the acceleration. Therefore, in the normal mode, the driver can easily control the vehicle speed by operating the accelerator pedal 4. For example, in urban areas or on congested roads, the driver is required to frequently change the vehicle speed. However, the operation frequency and an operation amount of the accelerator pedal 4 can be reduced by selecting the normal mode to reduce driver fatigue due to accelerator pedal operation.

[0040] In the sport mode, however, the controller 6 uses the second acceleration characteristic to drive the vehicle Ve in a dynamic manner. In a case where the second acceleration characteristic is used, the target acceleration is also increased in accordance with an increase in the depression of the accelerator pedal 4 at a first change rate, but the target acceleration is decreased in accordance with an increase in the vehicle speed at a third change rate that is smaller than the second change rate. In particular, the third acceleration characteristic is determined with respect to the Fig. 6 and Fig. 7 shown characteristic curve fields.

[0041] In particular, Fig. 6 shows a characteristic map that determines the target acceleration in relation to the position of the accelerator pedal 4 in the sport mode at a first rate of change. In Fig. In Figure 6, line L7 shows a relationship between the target acceleration and the position of the accelerator pedal 4, assuming the vehicle speed is a2. Line L8 shows a relationship between the target acceleration and the position of the accelerator pedal 4, assuming the vehicle speed is b2. Line L9 shows a relationship between the target acceleration and the position of the accelerator pedal 4, assuming the vehicle speed is c2. Here, the vehicle speed b2 is faster than the vehicle speed a2, and the vehicle speed a2 is faster than the vehicle speed c2 (b2>a2>c2). As can be seen from Fig. As can be seen from Figure 6, the slopes of lines L7, L8 and L9 (i.e. the first rate of change) are identical to each other.

[0042] In the case that the first acceleration characteristic is used in the sport mode, as in Fig. 6, the target acceleration is increased in accordance with an increase in the depression of the accelerator pedal 4 at the first change rate. In this case, the first change rate is displayed as a slope of each of the lines L7, L8, and L9. Thus, the ratio of a change amount of a position of the accelerator pedal 4 to a change amount of the target acceleration is also set to the first acceleration change rate as a fixed rate. That is, the target acceleration is increased in accordance with an increase in the depression of the accelerator pedal 4 at the first target acceleration rate in both the normal mode and the sport mode. In other words, an increase rate of the target acceleration with respect to an increase in the depression of the accelerator pedal 4 is not changed even when the driving mode is switched between the normal mode and the sport mode.Therefore, according to the embodiment of the present invention, the vehicle Ve can be driven in a dynamic manner by switching the driving mode from the normal mode to the sport mode while preventing the driver from feeling uncomfortable.

[0043] The third change rate used in the Sport mode to reduce the target acceleration is smaller than the second change rate selected in the Normal mode. In other words, a slope of each line representing the third change rate in the following Fig. 7, individually weaker than the slope of each line representing the second rate of change in the above-mentioned Fig. 4. Therefore, the distances between lines L7 and L8 and lines L7 and L9 shown in Fig. 6 are narrower than the distances between the lines L1 and L2 or the lines L1 and L3 shown in the above-mentioned Fig. 3 are shown.

[0044] Fig. Figure 7 is a map that determines the target acceleration with respect to the vehicle speed Ve in the sport mode at the third rate of change. In particular, Fig. 7, line L10 indicates a relationship between the target acceleration and the vehicle speed, provided that the accelerator pedal 4 is positioned at a position A2, line L11 indicates a relationship between the target acceleration and the vehicle speed, provided that the accelerator pedal 4 is positioned at a position B2, and line L12 indicates a relationship between the target acceleration and the vehicle speed, provided that the accelerator pedal 4 is positioned at a position C2. Here, depression of the accelerator pedal 4 at position A2 is less than depression of the accelerator pedal 4 at position B2, and depression of the accelerator pedal 4 at position B2 is less than depression of the accelerator pedal 4 at position C2 (A2 <B2<C2). Wie aus Fig. As can be seen from Figure 7, the slopes of lines L10, L11 and L12 (i.e., the third rate of change) are identical to each other.

[0045] In the case of reducing the target acceleration in the sport mode, as in Fig. 7, the target acceleration is increased at the third rate of change in accordance with an increase in the vehicle speed. Specifically, the third rate of change is a ratio of a change in the vehicle speed to a change in the target acceleration, and Fig. 7, the third change rate is displayed as a slope of each of the lines L10, L11, and L12. According to the embodiment of the present invention, the relationship between a change amount of the vehicle speed and a change amount of the target acceleration is switched depending on the selected driving mode. Specifically, the second change rate is used in the normal mode to decrease the target acceleration, whereby the third change rate, which is smaller than the second change rate, is used in the sport mode to decrease the target acceleration.

[0046] Thus, according to the embodiment of the present invention, each of the lines L7, L8, L9, L10, L11 and L12 indicating the second acceleration characteristic are plotted in the Fig. 6 and Fig. 7. However, the second acceleration characteristic can also be changed to vary the target acceleration in a quadratic, logarithmic, or stepwise manner. The second acceleration characteristic can also be determined by a functional formula that defines a relationship between the target acceleration and the depression of the accelerator pedal or the vehicle speed. Instead, the second acceleration characteristic can also be determined by a control table that defines a relationship between the target acceleration and the depression of the accelerator pedal or the vehicle speed.

[0047] With reference to Fig. 8 shows the acceleration and speed of the vehicle Ve, which are changed in the sport mode, in which the Fig. 6 and Fig. 7 is used. Before point t21, the accelerator pedal 4 is positioned at position A2. The accelerator pedal 4 is depressed by the driver at point t21 such that the position of the accelerator pedal 4 is changed to position B2 at point t22. Consequently, the target acceleration is increased such that the acceleration of the vehicle Ve is increased from point t21 to point t22, and the speed of the vehicle Ve is increased from a2 to b2 during the period from point t21 to point t22. In this case, as indicated by the arrows in Fig. 6 and Fig. 7, the target acceleration has not yet been reduced to zero and still remains a predetermined positive value. That is, if the position of the accelerator pedal 4 is fixed in this situation, the speed of the vehicle Ve will continue to increase from b2. Therefore, to stabilize the speed of the vehicle Ve, the accelerator pedal 4 is returned from position B2 to position C2 at point t23. Consequently, the target acceleration is reduced to zero, and the speed of the vehicle Ve stabilizes after point t23.

[0048] Thus, in the sport mode, in which the second acceleration characteristic is used, the vehicle Ve can be driven at speed b2 by moving the accelerator pedal 4 from position A2 to position B2 to position C2 after depressing the accelerator pedal 4. That is, in the sport mode, the acceleration of the vehicle Ve changes rapidly in response to the change in the position of the accelerator pedal 4. This means that the acceleration depends more on the position of the accelerator pedal than the vehicle speed. In the sport mode, the driver is thus able to control the acceleration of the vehicle Ve in a more dynamic manner than in the normal mode.For example, if the driver intends to accelerate the vehicle Ve immediately, by depressing the accelerator pedal 4 and then maintaining the position of the accelerator pedal 4, a higher acceleration can be continuously generated to accelerate the vehicle Ve. That is, the vehicle Ve accelerates quickly with a simple operation. Therefore, in the sport mode, the agility of the vehicle Ve can be improved compared to the normal mode.

[0049] Thus, according to the embodiment of the present invention, the speed of the vehicle Ve can be easily controlled in the normal mode by operating the accelerator pedal 4. Whereas, in the sport mode, the acceleration of the vehicle Ve can be quickly changed in a dynamic manner in response to an operation of the accelerator pedal. Therefore, according to the embodiment of the present invention, the vehicle Ve can be operated in accordance with the driver's intention in each driving mode.

[0050] Fig. 9 is a characteristic map used in another embodiment of the present invention to reduce the target acceleration. As shown in Fig. As shown in Figure 9, according to another embodiment, a target acceleration range is divided into a high acceleration range and a low acceleration range using a reference acceleration value. The reference acceleration, as a boundary between the high acceleration range and the low acceleration range, is set to a predetermined positive value based on a result of experiments or simulations.

[0051] According to another embodiment described in Fig. 9, the first acceleration characteristic is used in the normal mode. In the case where the normal mode is selected, in the high acceleration range, the target acceleration is decreased in accordance with an increase in the vehicle speed Ve at a fourth change rate smaller than the second change rate. Whereas, in the low acceleration range, the target acceleration is decreased in accordance with an increase in the vehicle speed Ve at a fifth change rate greater than the fourth change rate. Note that the fourth change rate may be identical to the second change rate.

[0052] Likewise, according to a further embodiment, the Fig. 9, the second acceleration characteristic is used in the sport mode. In the case where the sport mode is selected, in the high acceleration range, the target acceleration is decreased in accordance with an increase in the vehicle speed Ve at a sixth change rate that is smaller than the third change rate. Whereas, in the low acceleration range, the target acceleration is decreased in accordance with an increase in the vehicle speed Ve at a seventh change rate that is greater than the sixth change rate. Note that the sixth change rate may be identical to the third change rate.

[0053] Thus, according to another embodiment described in Fig. 9, in both the normal mode and the sport mode, the rate of change (i.e., reduction rate) of the target acceleration with respect to an increase in the vehicle speed is increased in the low acceleration range and reduced in the high acceleration range. According to a further embodiment shown in Fig. Therefore, as shown in Figure 9, a speed of the vehicle Ve can be easily controlled in the low acceleration range, and an acceleration of the vehicle Ve can be easily controlled in the high acceleration range. For these reasons, the vehicle Ve can be operated in accordance with the driver's intention based on the target acceleration.

[0054] Fig. 10 is a characteristic map used in yet another embodiment of the present invention to reduce the target acceleration. As shown in Fig. As shown in Figure 10, according to yet another embodiment, a speed range of the vehicle Ve is divided into a high speed range, a medium speed range, and a low speed range to reduce the target acceleration. For example, a limit speed between the low speed range and the medium speed range is set between 20 and 30 km / h, and a limit speed between the medium speed range and the high speed range is set between 80 and 100 km / h. These limit speeds are also set based on a result of experiments and simulations.

[0055] According to yet another embodiment disclosed in Fig. 10, the first acceleration characteristic is used in the normal mode. In the case where the normal mode is selected, in the low speed range, the target acceleration is decreased in accordance with an increase in the speed of the vehicle Ve at an eighth change rate that is greater than a second change rate. In the middle speed range, the target acceleration is decreased in accordance with an increase in the speed of the vehicle Ve at a ninth change rate that is smaller than the eighth change rate. In the high speed range, the target acceleration is decreased in accordance with an increase in the speed of the vehicle Ve at a tenth change rate that is greater than the ninth change rate. Note that the eighth change rate may be identical to the second change rate.

[0056] Likewise, according to yet another embodiment described in Fig. 10, the second acceleration characteristic is also used in the sport mode. In the case where the sport mode is selected, in the low speed range, the target acceleration is decreased in accordance with an increase in the speed of the vehicle Ve at an eleventh change rate that is greater than the third change rate. In the middle speed range, the target acceleration is decreased in accordance with an increase in the speed of the vehicle Ve at a twelfth change rate that is smaller than the eleventh change rate. In the high speed range, the target acceleration is decreased in accordance with an increase in the speed of the vehicle Ve at a thirteenth change rate that is greater than the twelfth change rate. Note that the eleventh change rate may be identical to the third change rate.

[0057] Thus, according to yet another embodiment described in Fig. 10, in both the normal mode and the sport mode, the rate of change (i.e., reduction rate) of the target acceleration with respect to an increase in the vehicle speed is increased in the low speed range and the high speed range, and reduced in the medium speed range. According to yet another embodiment shown in Fig. Therefore, as shown in Figure 10, the speed of the vehicle Ve can be easily controlled in the low-speed range and the high-speed range, and the acceleration of the vehicle Ve can be easily controlled in the medium-speed range. For these reasons, the vehicle Ve can be operated in accordance with the driver's intention depending on the driving state and speed of the vehicle Ve.

Claims

[1] Vehicle control system, comprising: a detector (5) which detects an actuation amount of an accelerator (4) and a speed of a vehicle (Ve); and a controller (6) configured to to set an acceleration characteristic which determines a relationship between a target acceleration, the amount of operation of the accelerator (4) and the speed of the vehicle (Ve), to calculate the target acceleration in relation to the amount of operation of the accelerator (4) or the speed of the vehicle (Ve) based on the acceleration characteristic, to control an acceleration of the vehicle (Ve) based on the calculated target acceleration, to select a driving mode of the vehicle (Ve) from a normal mode in which a first acceleration characteristic is used as a standard acceleration characteristic, and a sport mode in which a second acceleration characteristic is used to drive the vehicle (Ve) in a dynamic manner, characterized by , that: the controller (6) is further configured to to increase the target acceleration in accordance with an increase in the operation amount of the accelerator (4) at a first rate of change and to decrease the target acceleration in accordance with an increase in the speed of the vehicle (Ve) at a second rate of change when the first acceleration characteristic is used in the normal mode, and increase the target acceleration in accordance with an increase in the operation amount of the accelerator (4) at the first change rate and decrease the target acceleration in accordance with an increase in the speed of the vehicle (Ve) at a third change rate which is smaller than the second change rate when the second acceleration characteristic is used in the sport mode. [2] Vehicle control system according to claim 1, wherein the controller (6) is further configured to in a high acceleration range that is higher than a reference acceleration value, to reduce the target acceleration in accordance with an increase in the speed of the vehicle (Ve) at a fourth rate of change that is smaller than the second rate of change, and in a low acceleration range that is lower than the reference acceleration value, to reduce the target acceleration in accordance with an increase in the speed of the vehicle (Ve) at a fifth rate of change that is greater than the fourth rate of change when the first acceleration characteristic is used in the normal mode, and in the high acceleration range, to decrease the target acceleration in accordance with an increase in the speed of the vehicle (Ve) at a sixth rate of change which is smaller than the third rate of change, and in the low acceleration range, to decrease the target acceleration in accordance with the speed of the vehicle (Ve) at a seventh rate of change which is greater than the sixth rate of change when the second acceleration characteristic is used in the sport mode. [3] Vehicle control system according to claim 1, wherein the controller (6) is further configured to in a low-speed range that is lower than a lower limit speed, to decrease the target acceleration in accordance with an increase in the speed of the vehicle (Ve) at an eighth rate of change that is greater than the second rate of change, in a medium-speed range that is higher than the lower limit speed but lower than the upper limit speed, to decrease the target acceleration in accordance with an increase in the speed of the vehicle (Ve) at a ninth rate of change that is smaller than the eighth rate of change, and in a high-speed range that is higher than the upper limit speed, to decrease the target acceleration in accordance with an increase in the speed of the vehicle (Ve) at a tenth rate of change that is greater than the ninth rate of change when the first acceleration characteristic is used in the normal mode, and in the low speed range, to decrease the target acceleration in accordance with an increase in the speed of the vehicle (Ve) at an eleventh rate of change that is greater than the third rate of change, in the middle speed range, to decrease the target acceleration in accordance with an increase in the speed of the vehicle (Ve) at a twelfth rate of change that is smaller than the eleventh rate of change, and in the high speed range, to decrease the target acceleration in accordance with an increase in the speed of the vehicle (Ve) at a thirteenth rate of change that is greater than the twelfth rate of change when the second acceleration characteristic is used in the sport mode.

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